Fixing a Distorted coiled Handset Cord, Improved method

[TelePlay]

I came up with a better mousetrap to fix a distorted coiled cord.

The first device I built worked but was too complex, complicated, slow and unable to monitor cord temperature. That "oven" is discussed in this forum topic:

https://www.classicrotaryphones.com/forum/index.php?topic=202.msg193428#msg193428

Threw that one out a few years ago when I came up with the idea for a better, faster and temperature monitor-able device. It's simple in design, easy to load the cord and cuts the heating time down to less than 5 minutes.

I just restored another cord which was almost completely stretched out.



After cleaning the cord with soapy water and allowing it to dry, I tightly wrapped the cord around a 3/8" diameter by 3' long aluminum rod (aluminum conducts heat quickly allowing the inside of the coil to be exposed evenly to about the same temperature as the exterior of the cord coil during heating.

I use an Infrared digital Thermometer to measure the cord temperature during the restoration process. To restore a coiled cord to its near original shape and function, the cord must be heated to 190-200 degrees F. Over 200 and the plastic cord will begin to melt, to deform. Under 190 and the cord will not be restored to its original elasticity. I check the cord at 4 or 5 locations every few minutes to make sure I get up to and stay in that range.

Once the cord temperature is in that range, it's done. Heat is turned off. In this instance, this is the coiled cord after restoration:





When approaching 200 degrees, the exterior surface of the cord begins to shine, the plastic begins to flow a bit turning the un-restored slightly dull surface to a more shiny surface. As soon as I see the shine start in part of the cord, I turn off the heat and check the temperature along the cord. Sections under 190 degrees receive a bit more heat to get a uniform heating over the full length of the coiled cord. You can see the difference in shine in the before and after images.

The heat gun I use is an industrial type used for shrinking heat wrap on pallets and other uses. The heat available is 4 to 5 times greater than a regular hair dryer. This is similar to the heat gun I use, I like the design in that the housing is flat, or straight, and makes it easy to mount it onto my heating rig with great stability. This heat gun comes with 4 attachments, one of which I bent into a semi-circular shape so that heat being blown out of the gun circles around the coiled cord.



This one is at this link, but links change over time. Searching eBay for "1500 W Heat Gun" brings up a lot of options, all about the same price.

https://www.ebay.com/itm/171241779932

This is the cord heating design I used and have used successfully many times. You can see the heat gun firmly mounted to a sled that slides back and forth along the aluminum rod with the bent attachment of the end of the heat gun surrounding half of the cord.



The bottom of the sled has 4 metal posts that ride in the two "U" channel guided and the sled moved on 4 wheels (plastic wheels removed and replaced with 2 washers on each wheel. I strip of A60 rubber was glued onto the board next to the "U" channels to provide a soft, grabbing "floor" for the metal wheels.

[TelePlay]

The proper use of this setup is critical to successful restoration of a distorted cord.

With the heat gun on, the sled is moved back and forth the full length of the rod and direction must be quickly changed at the end of each pass, less than 1/10 of a second. The change of direction "double heats" the cord on the ends so the ends will heat up twice as fast as the center section.

I move the sled about 1 foot a second and at the end of each pass, I rotate the rod 66 degrees. In 3 passes, the cord will have had an even amount of heat applied to it.

Reaching the end of each pass, the stopping of one direction and reversing the movement to the other means more heat is applied to the ends during direction change than applied to the rest of the cord during each pass. This can easily overheat the ends and ruin the cord. The ends will reach 200 degrees first, the "shiny" effect will be seen on the ends first.

At this point it is best to turn off the heat and take a temperature measurement on the ends and two or three spots along the rod. If the "center" of below 190 degrees, more heat must be applied to those areas to get the cord up to 190-200 degrees.

When done heating the cord to temperature, let it cool completely before removing the cord from the rod. If the cord was heated to 190-200 degrees, the inside of the coils will be slightly stuck to the aluminum rod, a good thing, and easily unstuck by rotating the coils.

If the is to be moved after heating, the entire length of the aluminum rod will be hot, 190-200 degrees. I remove the rod and place it in a cool corner of my basement to reach room temperature more quickly.

Finally, the sled is essential to keep the hot metal of the heat gun and end deflector from touching the plastic cord. If that happens, it will cut into and damage the cord.

[Stormcrash]

Did you still have to do the twist direction reversal to get the cord to spring together instead of apart? Neat rig otherwise

[TelePlay]

Did you still have to do the twist direction reversal to get the cord to spring together instead of apart? Neat rig otherwise

No, coiled the original cord tight on the rod and applied heat. Replicates how the cord was originally coiled. The heat allows the plastic to regain its original form. Goes on the rod as shown in the before image, comes off the rod as shown in the after images.

These were originally made by tightly winding a round cord on a rod and the rod was then heated electrically (something like a nichrome metal rod with its innate resistance) to around 200 degrees, allowed to cool and removed from the rod. Heading the rod caused the round cord to become flat against the rod. You can see that if you look at the inside of any coiled cord and between the coils. The way I heat it returns it to its original condition, as originally "melted."

I looked into buying a 3 foot nichrome 3/8" diameter rod to electrically heat the cord from the inside to fix coil distortion. That would allow an exact temperature over the entire rod and eliminate the risk of damaging the outside of the coil (the inner coil would always be hotter than the outer surface of the coil - my method makes the exterior of the coil warmer then the inner coil. I am not willing to spend a couple hundred bucks when I can about duplicate the restoration with less than $40 in equipment.

I am always amazed how good the restored coiled cord looks and feels when removed from the aluminum rod, regardless of how distorted and/or stretched the cord has become.

[TelePlay]

Neat rig otherwise

Thanks, works well but must pay close attention to the heat gun when it's turned on. The 1500W gun in high puts or 500-600 degree heat. If the sled stops with the heat on, the cord would melt in a second or two, that works ruin the cord in the spot the sled stopped.

I use a two temp gun but low temperature is 400 degrees, same danger, just takes longer to achieve the same results.

I see they now sell heat guns with a variable temperature option (about the same price) with a range from 122 to 1,024 degrees. If the heat gun could be set to 195 degrees, the cord would never get hot enough to melt and it would make the process easier to do. I don't need another industrial heat gun.

I always make sure I am wide awake and fully aware of all moving parts when heating a cord. Haven't ruined one yet.

[HarrySmith]

Nifty setup! That cord looks brand new.

[Stormcrash]

No, coiled the original cord tight on the rod and applied heat. Replicates how the cord was originally coiled. The heat allows the plastic to regain its original form. Goes on the rod as shown in the before image, comes off the rod as shown in the after images.

These were originally made by tightly winding a round cord on a rod and the rod was then heated electrically (something like a nichrome metal rod with its innate resistance) to around 200 degrees, allowed to cool and removed from the rod. Heading the rod caused the round cord to become flat against the rod. You can see that if you look at the inside of any coiled cord and between the coils. The way I heat it returns it to its original condition, as originally "melted."

I looked into buying a 3 foot nichrome 3/8" diameter rod to electrically heat the cord from the inside to fix coil distortion. That would allow an exact temperature over the entire rod and eliminate the risk of damaging the outside of the coil (the inner coil would always be hotter than the outer surface of the coil - my method makes the exterior of the coil warmer then the inner coil. I am not willing to spend a couple hundred bucks when I can about duplicate the restoration with less than $40 in equipment.

I am always amazed how good the restored coiled cord looks and feels when removed from the aluminum rod, regardless of how distorted and/or stretched the cord has become.

Interesting. I remember reading that the original manufacture process still involved reversing the coil direction as the last step, there's even a how it's made video showing them using a drill to do it on the "oh this is not the real machine/rig trust us" rig. Might still have issues of spreading out/loosening over time that the reversal helps counteract, but if it's properly springy right now then that's awesome.

[TelePlay]

I remember reading that the original manufacture process still involved reversing the coil direction as the last step, . . .

A link to that process would be great. And what type of cords they were taking about, cloth, original rubber, modern rubber, other would be of importance in the reverse coiling process.

The cords I heat restore are on post 302 phones. These handset cords have a flat inner side created by flowing the cord material during coiling. Looking at the inside of a coil not only shows the heat molded flat surface which sits on the metal rod but also a slight flattening of the coil sides, between coils, where the heated material slightly bonded/flattened against its adjacent coils. Only the outer coil is truly round.

Now, even more modern coiled cords appear to have started as a straight flat cord that is thinner and does not have a round outer coil. These can also be restored using this process.

The original coiled handset cords on F1 handsets started out as a much thicker  (fat) straight cord. The inner coil is only slightly flattened on these and there is very little flattening between the coils. The larger diameter rubber cord (that stiffens/hardens/deteriorates over time) was one of the first cord types they coiled. Being thicker, it might have required a lot more heat to get a strong coil and that might have damaged the inner conductors so if they didn't apply as much heat they might have had to reverse the coils to get a better spring. These are usually hard wired black coiled cords which do not restore well.

I don't know what they did. Observation and working with the different cords is all I have to go on - think about the problem, design a fix and see if it works, if not redesign the fix and see if it works.

And I've never worked on a cloth coiled cord, most of those I've seen don't hold their coil.

This heating restoration is intended for coiled handset cords produced after 1950 (introduction of the 500 and similar phones).

Finally, even if they reversed the coil during original production (which to me would seem like a lot of extra time to do that to the millions of cords produced each year on modern machinery), it would make sense NOT to reverse the coil during my heat restoration and thereby undoing what was done when originally created.

What I offer in my posts are reports of what I have found to work to resolve issues as a hands on, creative hobbyist - my opinions of the issue and the fix I found works. I have no idea of which BSP or WE patent or other documents would provide original processes. I offer ways in my restoration topics that I have found to fix/help restore a phone that I am then willing to sell to another person. I do this to pass on the information to others who may still be in the hobby of restoring undesirable "as found" phones. I doubt anyone is doing this these days so I'm posting my finds for possible future interest.

[Stormcrash]

A link to that process would be great. And what type of cords they were taking about, cloth, original rubber, modern rubber, other would be of importance in the reverse coiling process.

The cords I heat restore are on post 302 phones. These handset cords have a flat inner side created by flowing the cord material during coiling. Looking at the inside of a coil not only shows the heat molded flat surface which sits on the metal rod but also a slight flattening of the coil sides, between coils, where the heated material slightly bonded/flattened against its adjacent coils. Only the outer coil is truly round.

Now, even more modern coiled cords appear to have started as a straight flat cord that is thinner and does not have a round outer coil. These can also be restored using this process.

The original coiled handset cords on F1 handsets started out as a much thicker  (fat) straight cord. The inner coil is only slightly flattened on these and there is very little flattening between the coils. The larger diameter rubber cord (that stiffens/hardens/deteriorates over time) was one of the first cord types they coiled. Being thicker, it might have required a lot more heat to get a strong coil and that might have damaged the inner conductors so if they didn't apply as much heat they might have had to reverse the coils to get a better spring. These are usually hard wired black coiled cords which do not restore well.

I don't know what they did. Observation and working with the different cords is all I have to go on - think about the problem, design a fix and see if it works, if not redesign the fix and see if it works.

And I've never worked on a cloth coiled cord, most of those I've seen don't hold their coil.

This heating restoration is intended for coiled handset cords produced after 1950 (introduction of the 500 and similar phones).

Finally, even if they reversed the coil during original production (which to me would seem like a lot of extra time to do that to the millions of cords produced each year on modern machinery), it would make sense NOT to reverse the coil during my heat restoration and thereby undoing what was done when originally created.

What I offer in my posts are reports of what I have found to work to resolve issues as a hands on, creative hobbyist - my opinions of the issue and the fix I found works. I have no idea of which BSP or WE patent or other documents would provide original processes. I offer ways in my restoration topics that I have found to fix/help restore a phone that I am then willing to sell to another person. I do this to pass on the information to others who may still be in the hobby of restoring undesirable "as found" phones. I doubt anyone is doing this these days so I'm posting my finds for possible future interest.

Found it
https://youtu.be/qWoGHc8yhOE?si=HOGnePSsU8z1NnDQ&t=231

Link goes to the part right before when it's being taken off of the rod.

As far as I know this goes for both hardwired and modular vinyl cords for phones, and I know it also applies to making or repairing coiled cords for computer keyboards

[TelePlay]

Using Google AI search, it came up with this.

"Western Electric's coil handset cords were made possible by a process that involved heating a straight cord and winding it around a mandrel or coil former to achieve the spiral shape.

This process, combined with the use of flexible materials like PVC or polyurethane, allowed the cords to stretch and retract without tangling or breaking, providing more flexibility for users.

Here's a more detailed explanation:

Materials:

The cords typically contained two or four copper conductors (wires) inside, insulated and then jacketed with a flexible plastic material like PVC or polyurethane.

Coiling Process:

The key to the coiled shape was the heating and winding process. The straight cord was heated and then tightly wrapped around a cylindrical tool called a mandrel or coil former.

Retraction and Flexibility:

When the cord cooled, it retained the spiral shape, allowing it to stretch and retract. This design addressed the issue of cable slack and tangling, giving users more freedom to move around while on the phone.

Western Electric and the 500 Series:

The coiled handset cord became standard on models like the Western Electric Model 500 and other business desk phones, making them a common feature of mid-20th-century telephones, according to Autac Inc."

I can see heating the straight cord before or just as it's wrapped around a mandrel. That's what I would expect from WE mechanical engineers designing the manufacturing process for continuous production of many cords. A much quicker process than heating the mandrel after the cord is wrapped around it.

I still don't see the step of reversing the coil to be necessary or cost effective on >1950 cords produced this way.

I do remember members who tried to restore a coiled cord with a lower heat (hairdryer) device got some results and discovered reversing the coil improved the coiled cord features. I've found that heating the cord to 190-200 F does not require reversing the coil.

[TelePlay]

Found it
https://youtu.be/qWoGHc8yhOE?si=HOGnePSsU8z1NnDQ&t=231

Link goes to the part right before when it's being taken off of the rod.

Thanks! Interesting.

They heat the cord to 90C or 194F, what I discovered by trial and error.

But I would say this is a modern production facility designed and built well after WE stopped making telephone and parts for them.

The cords they are producing are not the same (interior components) as those used in WE cords.

I do know there are many facilities out there today that produce coiled and cloth covered cords for companies needing whatever to build the product. A machine to weave a cloth cover over 1 to 8 conductors is a marvel to watch.

This video you found is equally interesting and informative.

It may be their heating the cord on a mandrel in an oven would be the reason reversing is needed. If WE wrapped hot wire around a cold mandrel, that may have eliminated the need to reverse - their coiled cord was tight to begin with.

It would be interesting to see a video from the 50s showing how WE heated the round wire to around 200 F as it was wrapped on a cold mandrel.

[TelePlay]

This is a comparison of coiled cords: F black, G Black, G red and modern repro yellow.

This would support the idea that WE first heated the G cords to around 200 F and then wound them around a mandrel. Pulling a hot cord around a round rod would cause the thickness of the original round cord to be less than the width of the cord (coil thickness vs coil width in the chart). Pulling a heated cord around a mandrel while pressing the sides together would result in the full flat inner side and about a half flat inner side (the place where the coils touch together) of G coiled cords. I doubt these "heated first" cords would need a reverse twist.

The F cord is much larger and due to what it is make of, may not have been heated before wrapping in that not as much deformation occurred and the sides between the coils show 1/10th of the flatness seen on G coiled cords. The coil itself of an F coiled cord is not as tight as the G coiled cords and would possibly benefit from a reverse twisting.

The repro yellow modular cord in the chart is just different but can be heat restored, carefully in that the cord is so much thinner and will heat up faster. These cords are those that are found for sale at many stores and other places today.

There are other varieties of coiled cords out there, I just looked at these that I had readily available and had heat restored (excluding the F cord).

There are quite a few videos on YouTube from DIY engineers who have tried to coil all sorts of straight cords. They all use the "wrap and heat" process. None of their coiled cords are as tight as a WE G cord either NOS or restored. These basement hobbyists have the idea but not the equipment used by the commercial cord producer (wrap and then heat process) shown in the YouTube video above.

I can not find a vintage video of WE making coiled cords. The first coiled cords were said to have been produced in the 1930s. By the time WE got to the G handset, I'm sure their engineers came up with the best, cheapest, fastest and highest volume equipment to make the best quality coiled cords. That's the equipment or process I have yet to find. Even a Patent filing would help.

[TelePlay]

Found this 1942 Patent given to Western Electric which does include reversal of the coils to create a tighter coil (paragraphs 6 & 7). What is not stated is what cord this would be used on, a fatter F handset cord or the newer material G handset cord.

This posted text seems to be from a scanned document so plenty of spelling issues and many difficult to interpret words, especially at the end. Fortunately, the original document and supporting image are attached below in a pdf file. The image in the pdf file shows a flat cord



design so which cordage this process was used on is not known. Also not stated is how the material was heated to create the helix.

===================

Retractile Conductor Cord And Method Of Making Such A Cord

Document ID:  US 2271057 A
Date Published:  1942-01-27

Inventor Information
Name:  BARRANS WILLIAM T

US Class Current:
264/171.16,264/339,267/69,264/281,174/69,264/285

CPC Current
Type:  CPCI
CPC:  H 01 B 7/06
Date:  2013-01-01

Description

UNITED STATES PATENT OFFICE

(1) 2,271,057  RETRACTILE CONDUCTOR CORD AND METHOD OF MAKING SUCH A CORD

(2) Wvilliam T. Barrans, Towson, Md., assignor to Western Electric Company, Incorporated, New York, N. Y., a corporation of New York Application May 12, 1939, Serial No. 273,174 3 Claims. (Ci. 174--09) This invention relates to a retractile conductor cord and method of making such a cord, and more particularly to a retractile cord of helically coiled form and method of making such a cord.

(3) In the telephone and other arts it is frequently desirable to connect electrically operated devices by a compact cord whose length may be extended by a slight tension and returned to a compact form when the tension is released.

(4) Objects of the invention are to provide an effective and efficient retractile cord and a method of making such a cord.

(5) In accordance with one embodiment of the in- vention, a plurality of conductors are encased in a rubber sheath and vulcanized into a helical coil, after which the convolutions of the coil are inverted or reversed to increase the retractility of the coil.

(6) A complete understanding of the invention may be had by reference to the following de- scription, taken in conjunction with the- accompanying drawing, in which- Fig. 1 is a detail view of a retractile cord with a rubber sheath in the form in which it appears immediately after vulcanization of the sheath;
and

(7) Fig. 2 is a similar view of the same cord after the convolutions have been reversed.

(8 ) Referring now more in detail to the drawing, a retractile cord is shown having one or more conductors 5 which are encased in a sheath 6 of rubber or other suitable material. The rubber sheath 8 may be extruded upon the conductors in any well-known manner, after which the sheathed conductor is wound upon a mandrel in helical form. It is to be understood that the term helical is used in its broadest sense and will represent a coil or spiral produced when a strand is wrapped about a mandrel the transverse cross section of which may be triangular, square, rectangular, circular, oval or a modification of any of these. The rubber sheath of the cord is then vulcanized on the mandrel. When a cord thus made is suspended from one end the convolutions tend to separate due to the weight of the cord, Indicating thnt ,re initil ret.ractiiity is+ not very high. 1me tendency for the coil to ret" pct into cltsely oilzii convn1lutionn cnn? 1;: areatly 1nrca by revf.-ing "'te con..

(9) volutions,! ane 5reater the uao -ng+ bztw -cn con?- volutions within reasonable limits the greater will be the retractility of the cord. This inverting of the convolutions may be accomplished by beginning at one end and inverting each convolution separately. However, a more effective way of reversing the convolutions is by taking a rod 7 in the form of an enlarged needle having an eyelet 8 at one end, proj ecting it through the coil, and inserting the ends of the conductors 6 t i through the eyelet. Then by drawing the needle through the coil all of the convolutions of the coil may be inverted from right-hand convolu- tions, as shown in Fig. 1, to left-hand convolu- tions, as shown in Fig. 2. If it be desired that i5 the final form of the coil have right-hand convo- lutions, the coil is originally made with left-hand convolutions and then inverted. By this mheans a closely coiled cord having a high degree of retractility may be made.

(10) 20U While the invention has been described in connection with a retractile coil having a vulcanized rubber sheath, it will be understood that the invention is applicable to other types of cords, and many modifications and changes may be made 23 in the specific embodiment described without departing from the spirit and scope of the invention.

Claims

1. A method of making a retractile cord which' comprises extruding a continuous unvulcanized rubber sheath on a flexible conducting core, forming the resulting product into helical form; vulcanizing the sheath on the core to form a retractile cord and inverting the helix to increase 33 the retractility of the cord by drawing one end of the cord through the helix.

21. A method of making a retractile cord which comprises applying a continuous unvulcanized rubber sheath directly on a flexible conducting core, thereafter forming the resulting product into helical form, vulcanizing the sheath on the core to form a retractile cord and inverting the helix to increase the retractility of the cord by drawing one end of the cord through the helix. 43 3. A method of making a retractile cord which comprises coating a conductor with thermoreac-tive umaterial, for=Wing the coated cord into retractile forui, se'tting sA1d thernnoracilte .:ate-ritIt in the formn Of a he!lix, and drawing One end of the cord through the he~i~z to Invert ±shO cor w; rrT TATS Z, MA.A1 ,

[TelePlay]

Then there is this Patent given to Kellogg Switchboard in 1946 for the creation of a continuous length of coil cordage with, as seen in the patent drawings, a "hump" at times that is used to cut the continuous length apart and provide a bit of straight cordage to affix a proper end connector.



This patent description does not include a step to reverse the helical coils. The patent doesn't say much about how the cordage is heated to create the coiled cord, vulcanizing the cordage on the mandrel.

The original pdf format patent with images is attached in that the following text again contains numerous scanning errors.

=================

Method Of Making Elastic Coil Cables

Document ID:  US 2394762 A

Date Published:  1946-02-12

Inventor Information

Name:  GERATY PAUL C

US Class Current:  264/139,29/868,174/69,174/113R,264/DIG.40,264/281

CPC Current

Type:  CPCI, CPCA, CPCA

CPC:  H 01 B 13/008, Y 10 S 264/40, Y 10 T 29/49194

Date:  2013-01-01, 2013-01-01, 2015-01-15

Description

UNITED STATES PATENT OFFICE

(1) 2,394,782

METHOD OF MAKING ELASTIC COIL CABLES

(2) Paul C. Geraty, Chicago, Ill., assignor, by mesne assignments, to Kellogg Switchboard and Supply Company, Chicago, Il. a corporation of Illnois, and to Ralph D. Collins, Beverly Hills, Calif.

(3) Applcation August 25, 1944, Serial No. 551,246 2 Claims. (CI. 18--47.5) The present invention relates to a method of making elastic coil cables.

(4) It is flow well known that retractile and extensible extension cords or cables, for various pur- poses, principally electrical, may be satisfac- b torily constructed by providing a conductor or a plurality of conductors with a covering or sheath of incompletely vulcanized rubber or the like, then closely coiling it into the form of a helix, and then vulcanizing it, after which the cable will be 1C readily extensible, as, for example, for extension cord purposes, without damage thereto while being automat~cally retracted by its own resilience to closely coiled helical formation when released. Is For certain broader aspects of the subject- matter" here disclosed see Collins application Serial No. 577,111, filed February 9, 1945, and for certain other aspects see Arnold application .Serial No. 551,245, flied August 25, 1944. Zi] The present invention aims to set forth improvements in methods of making cables of this class, and will be understood by reference to the following description, taken together with the accompanying drawing, showing illustrative em- 28 bodiments of the invention, and in which:

(5) Figure 1 is a view of a. plurality of preliminarily interconnected lengths of cordage of this type before the lengths are severed to provide a plurality of individual cables, and as the, unsevered preliminarily continuous lengths may be pre- pared, in accordance with the present invention, for curing, and showing in this instance three humps formed in the cable separating the respective lengths; 353 Figure 2 is an enlarged view showing a portion of the structure of Figure 1 at one of the humps and in this instance the middle one;

(6) Figure 3 is a cross-section taken on the line 3-3 of Figure 2; - Figure 4 is a further enlarged fragmentary view of a portion of the cable with the outer covering broken away and showing the individual, enclosed conductors;

(7) Figure 5 is a view on the scale of Figure 1 show- 4b ing an individual length of cable after the humps at each end of such length have been severed, the cable being in retracted condition; and r igure shows the cable of r'igure 5 in sorme- what extended or stretched condition.

(8 ) Rieferring iin detail to the drawing an~d looking Iirst at Figure 4 thereof, it will be seen that the cable or conductor cord to which the present invention prrain.s is here shown as coiprising three separately insulated wire electrical conduc- '-'- tors 10, ! I and I2 which are each Provided with the usual insulation 1 3, 14 and 15, respectively, and which furthermore are braided or twisted together to form a joint helix !16, each of the separate insulated conductors 10, ! I and i 2 being also individually in the form of a helix..

(9) The joint helix 16 thus formed is encased as by extruding thereupon a uniform coating or sheath of somewhat pliable vulcanizable material " 1, psuch as a rubberlike substance either of conventional somewhat raw rubber or of a synthetic elastomer of whl~h there are many now on the market. The continuous sheath I1 say of rubber may be preliminarily cured to the extent in this binstance so that the ruhber will rot be readily distorted or adhere to adjacent rubber surfaces upon further vulcanization.

(10) Next the whole is coiled again into another exterior helix 18, with, desirably, the convolutions Sof the exterior helix ! 0 rotating in the same direction as those of the interior helix 6S. By this is meant that if one were to look at either end of the helix, the direction of rotation of the convolutions or pitch is somewhat similar to a right- bhand thread on a screw in that it proceeds clockwise about the common axis as the convolutions lead away from the eye of the beholder.

(11) The formation of the braided helix 16 and its sheath 17 of vulcanizable material is not a Part of the present invention, but this invention begins with the intermediate product thus formed and with the Production thereof into the exteriorly coiled helix 1 8 and the subsequent treatment thereof to produce the readily extensible and retractile elastic coil cables first herein above men- tioned, the details of which as here specifically set forth and following the present invention will next be described.

(12) For producing the exteriorly helically coiled cables, a mandrel may be provided in the form, as here shown, of a metal rod 19 upon which the cable initially in somewhat straight continuous formation as at 1 1, may be coiled and later may be placed in an oven or the like for vulcanizing as here subsequently more particularly referred to. For coiling purposes, the rod 19 may be mounted in any suitable chuck-like supports for rotation on its longitudinal axis, which supports and I1leans~ of rotation fori'i no part of the present invention and are therefore not here shown, It being suijicient for the present purposes to state that thre mandlrel or rod !19 3_c suitably rotated and the cable iiiay be inrtroduced mnanu~ally thereupdnn for coiling.

(13) It will be observed that the coiling of the cable on the rod 19 is in a direction to produce the clockwise or righthand thread convolutions i 0 already referred to, it having been found that this coiling of the outer helical in the same direction as the coils of the inner helical 16 of the separate conductors causes these helices to work together instead of against each other, particularly in that when the cable is manipulated the inner helices {16 do not tend to become untwisted, wvhen retracted or extended as in the final product shown in Figures 5 and 6.

(14) It is desirable that a particular length of such cable 20, individually shown in Figure 5, should have at each end a connecting tall 21, for any desired extension cord purposes, as, for example, for attachment at one end to the base of a so- called cradle-type telephone, and, at the other end, to- the receiver-transmitter of the telephone, and, furthermore it is advantageous, for speed and economy of manufacture, that a plurality of the individual cable lengths shown in Figure 5 be preliminarily connected together prior to and during curing.

(15) In accordance with the present invention both of these objects, that is, the formation of the connecting tails and the economy of production are accomplished by using a rod I9 which is long enough, as shown in Figure 1, to accommodate a plurality of preliminarily interconnected cable lengths 22, two such lengths being here shown merely by way of example, it being understood that three or four such interconnected preliminary lengths of cable as at 22 might be disposed on a single rod 19. the rod being made any length for that purpose within limits affording feasibility of rotation of the rod and the handling of the rod with the coiled cable thereupon.

(16) As here illustrated, beginning say at the left- hand end of the rod 19, a relatively short portion of the cable as at 23 may be manually wound about the rod 19 to effect an anchorage of the cable thereto for subsequent mechanical rotation. After winding the lead 22 of the cable on the rod, a portion of the cable is then formed uncoiled, as, in this instance by forming a hump 24 in the cable which is here formed by means extending transversely of the rod fI9, such as the post or peg 25. As best shown in Figures 2 and 3, the peg 25, conveniently made say of wood, may be a simple straight piece of slightly greater width than thickness and arcuately recessed at each end. The peg is placed in engagement with t' rod 19, the arcuate recess 20 at this end accommodating the curvature of the rod, the peg having its dimension of width crosswise of the rod. At its other or outer end, the peg is similarly arcuately recessed or concaved as at 21 and the cable led thereover to provide the hump 24 as at A, Figure 1, the hump thus being of V-shape and having the legs 29 and 29 and the concavity 21 receiving the cable to avoid slippage therefrom.

(17) As the leg 29 continues into the helical coil 22, to produce which the rod 19 may now be mechanically rotated, the peg 25 is maintained in position by the cable extending transversely of the rod and at the samie time the peg masintains the humip formation 24 in the cable. Ma the helical coiling of the cable on the rod continues and when sufincient cable hns been coiled to make any desired predetermcined length of individual cable, another peg 25 is Interposed As at H and another hunip 24 produced in the cable. Thereupon coiling is again continued to provide another preli~iinary cable length 22 and, 1n thtà instance, to effect a third hump 24 as at C.

(18) Finally a short length of the cable as at 20 may be manually coiled to effect an anchorage at this end of the rod.

(19) ;; The rod 19, with the coiled cable thereon, may now be removed from whatever mechanical support may have been employed for mechanically rotating the rod and the whole placed in the oven for curing, but before doing so, it is desirable to perform another of the steps of the present invention next referred to.

(20) It has been found that bubbles of air" or other gas are likely to be created within the interior of the cable during baking at the places where 1b the humps 24 occur unless means are provided for preventing this, and which would otherwise impair the cable. To prevent this, I desirably vent the cable where the humps are formed, as in this instance by cutting through the sheath 11, with a scissors or knife to effect a notch 21 in the cable advantageously at the apex of the hump 24 where it passes around the outer end 21 of the peg 25 and on the outer side of the cable, thus permitting gas or air which expands at the hump during baking to escape without causing the creation of bubbles, or gas pockets.

(21) After vulcanization of the cable on the rod I1S to any desired degree to produce a permanent set of the cable in helical form and to a degree which makes the vulcanizable material I1 springy and resilient, the rod 18 with the cable thereon is removed from the oven and the humps 24 are then completely severed conveniently at the places where the notches 31 occur, and the cable is then slipped from the rod 19.

(22) It will now be understood that, as here illus- trated, there will have been formed two individual lengths of cable 20, as shown in Figure 5, from each of the preliminary lengths 22 shown in Figure 1, and that the hump legs 29 of the humps A and B at one end of each of the preliminary cable lengths 22 now provide a connecting tail or tangent as at 21 at the left-hand side of Figure 5 for the final individual cables 20, and that ib the legs 28 of the humps B and C provide the other connecting tail or tangent at the right- hand side of Figure 5 for the individual cables 20. The leg 28 of hump A and the leg 29 of hump C, which remain integral respectively with lead- bing end 23 and the trailing end 30 of the cable, are discarded with these anchorage portions 22 and 20.

(23) As suggested in Figure 6 the helically coiled cable 20 is readily extensible, Figure 6 being bb merely suggestive of this and the cable in fact being extensible to a much greater extent than shown in Figure 6 to in fact almost, say, somewhat flatten out the coils while still being readily retracted automatically by its own resilience to closely compacted helical formation as at 20, when released, and thus having many useful applications where the requirements call for a well insulated and durable electric cable which is extensible and automatically retractile so as to avoid becoming entangled with other objects or being in the way of the user.

(24) It is to be understood that the tern'i helical is used here in its broadest sense and represents a coil or spiral produced when a strand is flexuously compacted about a xiandrel or a plurality of miandrels the transverse cross-section of which mnay be triangular, square, rectangular, circular, oval or any mrodification or comibination of these shape s produced with or without a xziandrel.

(25) 7f IHy elastomcer is meant any natural or synthetic rubber, plastic or rubber substitute exhibiting suitable characteristics of toughness, elasticity, extensibility and resilence, the product known as Buna 8, for example, being suitable.

(26) The reference to a vulcanizable material is intended to cover any rubberlike material, such as so-called Buna 8, which is capable of being set to a springy, resilient condition by suitable treatment and also the reference to vulcanizing the material is intended to cover the curing or the like of a rubberlike material by heat or any suitable treatment for the purpose.

(27) It Is furthermore to be understood that the invention is not intended' to be limited to details of sequence of operation of the methods here disclosed to exemplify the practice thereof, and such changes may be made as fall within the scope of the appended claims without departing from the invention.

(28) The invention having been described, what Is here claimed is:

(29) 1. The method of making elastic coil cables rendered elastic by having a covering of rubberlike material which is characterized by the steps of coiling a plurality of separately insulated conductors together each in the form of a helix and braided together forming a joit helix, ,encasing the conductors in a sheath of vulcanizable elastic material to form a cable, coiling the cable in another exterior helix, with the convolutions of said exterior helix rotating in the same direction bas the coils of the helices of said conductors.

(30) discontinuing said exterior helix, forming a hump in the cable where said exterior helix is discon- tinued, notching the sheath adjacent the apex of said hump to provide a vent, vulcanizing the cable, and severing the hump to provide an uncoiled end for the cable, whereby said uncoiled end is adapted to serve as a connecting tangent for the cable.

(31) 2. The method of making elastic" coil cables of the class described which Is characterized by encasing a conductor in a sheath of vulcanizable material to form a cable, comprising the steps of coiling the cable in a helix, discontinuing, the helix in the form of a hump including a pair of 0 legs and an apex, cutting into the sheath adjacent the apex of said hump and on the exterior of said hump to provide a vent, vulcanizing the material, and severing the hump adjacent said vent whereby one of said Legs provides an uncoiled end for the cable, said uncoiled end being adapted to serve as a connecting tangent tall for the cable, PAULh C. CGERATY.

[TelePlay]

Last one, a Patent given to Kellogg Switchboard in 1949 for the machine used to create coiled cords. The machine take cordage right out of an extruder and coils it into a continuous length. The process does not include reversing the coils.





There may be other patents out there given to other companies around this same time period but I am stopping my search having found an older patent reverses the coils and the newer patents do not. Don't know for sure but it might be the early 40s cordage material did not work as well as modern thermoplastic materials in producing and maintaining a coiled cord.

The original patent document in pdf format are attached. The following text is again filled with scan errors.


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Device For Feeding And Tensioning Raw Cordage In The Production Of Coiled Cords

Document ID:  US 2478454 A

Date Published:  1949-08-09

Inventor Information

Name:  BOSH JAMES E

US Class Current:  425/328,425/391,242/447.3,242/151,264/DIG.40

CPC Current

Type:  CPCI, CPCI, CPCA, CPCA, CPCA

CPC:  B 29 C 48/355, H 01 B 13/008, B 29 C 48/05, Y 10 S 264/40, B 29 C 48/06

Date:  2019-02-01, 2013-01-01, 2019-02-01, 2013-01-01, 2019-02-01

Description

(1) U LU vXOX

UNITED STATES PATENT OFFICE

(2) 2,478,454

DEVICE FOR FEEDING AND TENSIONING

(3) RAW$ CORDAGE IN THE PRODUCTION OF COIL.ED CORDS James E. Bosh, Berwvyn, Ill., assignor, by direct and mesne assignments, to Kellogg Switchboard and Supply Company, Chicago, Ill., a corporation of Illinois Application May 26, 1945, Serial No, 595,952 10 Claims. (Cl. 18-19 ) 1 This invention relates to apparatus for producing coiled cords for use, for example, in connection with telephone instruments, and is par- ticutlarly concerned with a device for feeding raw cordage to a winding arbor and for applying tension to the raw cordage on its passage to the arbor.

(4) A cord of this type comprises a plurality of insulated electrical conductors encased or enveloped in a flexible protective sheath or cover- ing, for example, a covering of a suitable plastic or rubber composition. The raw cordage, i. e., the conductors encased in the plastic covering, is extruded from a forming nozzle and is then wound around an arbor to form a tubular structure with the coils disposed close to each other.

(5) The plastic or rubber material of the coiled structure is then vulcanized so as to set the material in close coiled condition. A desired length of such coiled cord is employed for interconnecting telephone instruments, e. g., a receiver with a desk or a wall set. The cord is normally retracted by the' tendency of the coils to assume their close-coil positions and is extended during the use of the telephone instrument to form an open spiral-like structure so as to permit manipulation of the receiver. Upon replacing the receiver, the coils of the cord again retract to normal close-coil position. -In other words) th~e structure functions in the manner of a coiled spring. The use of such a coiled cord eliminates the necessity of employing auxiliary devices for keeping the cord tidy and unraveled, and thus reduces to a minimum annoyance-to the user of the telephone instrument as well as wear and tear on the cord.

(6) The invention furnishes a simple and efficient device comprising pressure rollers for engagement with the raw cordage and means for ad- JTlstiog such rollers to apply desired pressure on the raw cordage as it passes from the extrusion and forming nozzle to the winding arbor or mandrel. The cordage is thus tensioned with respect to the arbor. Tihe new tensioning device contributes toward uniformity of the cord throughout its length and toward uniformity of the coils formed on the winding arbor.

(7) An embodiment of the invention is shown in the accompanying drawings, wherein tig. i shows a diagrammatic front view of the device;

(8 ) rig. 2 illustrates the device in side view as seen from the left in r'ig. 1;

(9) rig. 3 is a top view; and 2 Fig. 4 represents a section taken approximately along lines 4-4 in Fig. 2 to show details.

(10) The drawings are more or less diagrammatic and are intended for illustrative purposes only.

(11) Known elements will be described merely to the extent required for an understanding of what is considered new. Identical parts are indicated by identical reference numerals throughout the drawings.

(12) Numeral I I indicates a base plate having at one end an upright 12. A similar upright is provided at the other end of the base plate. Jour- nalled in these uprights is the winding arbor or mandrel £ 3. A drive for the arbor 13 is schema cally indicated in the form of a V-pulley  driven by belt 1 5. Any other suitable and approved driving means for the arbor may, of course, be used.

(13) Also mounted in the uprights 12 is a supporting member shown as a shaft I6 for holding the new tensioning device which is generally indicated by the numeral 17. This tensioning device is longitudinally movable on the supporting mem- 25ber 15 and is angularly rotatable thereon.

(14) 25The tensioning device comprises a pair of cord guide rollers 18I and 28 which are rotatably disposed between two forwardly projecting frame members, shown as strips or bar-like members 1 9 and 20. The frame members £9 and 20 w the guide roller £8 are rotatably disposed an supporting shaft 16. Attached to the frame member I9 is a downwardly depending bar-like mounting member 21, and attached to the frame member 20 is a similar downwardly depending : bar-like mounting member 22. Each of these downwardly depending mounting members is angularly formed at its lower end, to provide brackets 23-24 for rotatably journalling guide rollers 25-25, respectively. The latter ride along the forward edge 21 of the base plate 11, which edge is disposed in a plane extending in -parallel with the axes of the arbor 13 and shaft ÂÂ The supporting structure of the tensioning device is thus rotatable about the shaft IS and is also movable along the shaft IS longitudinally thereof and in parallel with the axis of the arbor ÂÂ Angular brackets 28 30 are attached to the downwardly depending bar-like members 2£ respectively, forming supports for the downwardly extending holders 33 -34 which are provided with grooved pressure or tensioning rollers 3£ 32. 'he roller 31 is rotatably mounted the lower end of the holder 33 which is fixedly attached, e. g., by welding, to the angular bracket 29, and the roller 32 is rotatably mounted on the holder 34 which is hingedly or pivotally attached to the angular bracket 3®, for example, by me of a pivot screw 35.

(15) The pressure and tensioning rollers 3 Q-32 thus form a channel for receiving and guiding the raw cordage. The pressure or tensioning roller 31 is mounted in a fixed or stationary position, and the roller 32 is relatively movable thereto around the pivot point formed by the screw 35.

(16) The holder 33, as particularly shown in Figs. 2 and 4, is provided with a rearwardly extending boss 401 which is attached thereto by suitable means, for example, a screw 4!. Secured to the boss 40 is a pin 42 extending horizontally in back of the holders 33-34. The holder 34 carries a similar boss 43 which is secured thereto bay means of the screw 44. The boss 43 is provided with a boring for accommodating the pin 42 which extends therefrom, as shown, and is threaded at its free-end for receiving the adjusting nuts A5-46.

(17) A spring 47 is disposed on the pin 42 between the boss 43 and the nut 4+5. The pressure of the spring 47 .tensions the pivotally mounted holder 34 against the stationary holder 33, th~ereby pressing the roller 32 elastically against the roller 31.

(18) The pressure of the spring 41 may be adjusted by -means of the nuts 45-48, as desired. The pressure exerted by the roller 32 in the direction of the roller 31 is effective on the raw cordage 48 -moving in the channel defined by the rollers, thus -determining the tension thereon. Pressure from a few ounces to several pounds may be produced as desired, by using suitable springs and proper adjiustment of the nuts 45-46.

(19) 'The raw cordage 48, comprising a plurality of conductors enveloped or encased ir' a plastic sheath, for example, a rutbber cormposition, is extruded from the forming nozzle indicated in dotted lines at 49.

(20) The operation of the device is as follows:

(21) The -free end of the raw cordage 8, as it -emerges from the extrusion and formin~g nozzle 49, is
initially- threaded through the channel formed by the pressure rollers 31-32 an.d is then placed on the cord guide rollers 22 , 13, and finally attached to the arbor @3. At the start -of the operation, the tensioning device is positioned substantially in line with the extrusion nozzle A9; that is to say, the channel formed by 'the pressure- rollers 31-32 is positioned above =the extrusion nozzle with the median center line approximately in alignment therewith. The nuts 45-46b are adjusted to hold the rollers 31-32 with desired pressure against the raw cordage. The drive for rotating the arbor !13 is -now started and adjusted to proper speed in accordance with the speed of extrusion of the raw cordage from the nozzle 49.

(22) The raw cordage is wound on the arbor ! 3, forming the close-coil structure indicated in Figs.

(23) 2 and 3 at 50. The forming of the coil structure on the arbor proceeds from left to right, as seen in Fig. 1. The tensioning device accord- iigly follows from left to right in the direction of the winding of the cord coil, being guided in its displacement on the shaft !16 which is disposed in parallel with the axis of the arbor 13.

(24) TIhe rollers 25 -26 carried by the brackets 23 -24 at the lower end of the downwardly dependin g mlounting rmermbers 21-=22, respectively, guide the displacement of the device along the surface formed by the forward edge 27 of the base plate .11I,-which surface extends in parallel with the axes-of-the supporting shaft 16 and the arbor !3.

(25) The median center line extending through the channel formed by the pressure and tensioning rollers 31-32 is thus progressively shifted or displaced with respect to the extrusion and forming nozzle 49, as seen in Figs. 1 and 3. The plastic raw -cordage extruded from the nozzle 49 follows the displacement of the tensioning device.

(26) The entire structure is thus elastically and yieldably mounted for sliding displacement in parallel with the axis of the shaft 16 and is rotatable about the shaft 16 to prevent any interference with =the winding operation and undesired stresses "on the cordage. The adjusted tension supplied by the pressure rollers 31-32 is uniformly effective throughout the winding of the cord coil.

(27) The primary function of the pressure rollers 31-32 is, of course, to supply the tension required for winding the cordage on the arbor.

(28) The raw cordage extruded from the nozzle 46 is, however, _in a somewhat plastic condition, and the pressure exerted thereon by the rollers 3l-32 contributes to the final forming of the cordage or, rather to say, it secures the form of the cordage determined by the forming nozzle. If de- sired, the tension of the pressure rollers 3 1-'a2 may be adjusted so as to supply a forming pressure on the cordage.

(29) Control means for signalling the end of the winding operation and, if desired, for automatically stopping .the operation-when the coil on the arbor has reached a certain point, may be provided as desired or necessary.

(30) Changes may be made within the spirit and scope of the appended claims.

Claims

1. In a machine for winding raw cordage which consists of a plastic sheath containing conduc-tors, to form a coiled cord of the type used for interconnecting telephone instruments, a positively driven -rotatable arbor for winding said cordage, a guide frame, a pair of freely rotatable grooved tensioning .rollers carried by said guide ,5 frame -for engagement with the raw cordage on its passage to said arbor, means -for adjusting the pressure .of said- tensioning rollers on said cordage for the purpose of tensioning the cordage with respect to the arbor, a pair of serially 5t) related freely rotatable grooved guide rollers carried by said guide frame for guiding the cordage on its passage from said tensioning rollers to said arbor, means for mounting said guide frame for free sliding displacement in parallel ,55. with the axis- of said arbor, and roller means carried by said guide frame for guiding the sliding displacement thereof.

2. In a machine for winding raw cordage which consists of a plurality of conductors encased in 00 a plastic sheath, to form a coiled cord of the type adapted for interconnecting telephone instru-ments, a rotatable positively driven arbor for winding said cordage, a supporting member disposed in parallel with the axis of said arbor, a B5 par of arms pivotally and longitudinally slidably disposed on said supporting member, means rigidly connected with one of said arms forming a stationary holder extending therefrom , means pivotally secured "on the other arm forming a movable holder extending therefrom, a grooved roller carried by each- of said holders for engagement with the raw cordage on its passage to said arbor, spring-controlled means for resil-iently coupling said stationary holder with said pivotally secured holder, means .for adjusting said spring-controlled means to determine the pressure exerted on the cordage by the rollers carried by said holders, means forming a bracket extending from each of said arms, a guide roller carried by each of said brackets, and means forming a stationary guide extending in parallel with the axis of said arbor for engagement witb said guide rollers.

3. Inl combination, a positively driven rotatable arbor for winding thereon a member fed thereto to form a coil thereof, means forming a guide frame, means for mounting said guide frame for free sliding displacement parallel to the axis of said arbor and for angular displacement relative thereto, means carried by said guide frame forming a stationary holder and a movable companion holder thereon, a grooved roller carried by each holder for free rotation thereon, said rollers forming a channel for receiving said member, maeans for resiliently pressing the roller carried by said movable holder against the roller carried by said stationary holder for the purpose of exerting pressure on said member to tension it on its passage to said arbor, a freely rotatable guide roller on said frame for guiding said tensioned member on its passage from said channel to said arbor, means forming a guide surface extending in parallel with the axis of said arbor, bracket means carried by said guide frame, and roller means carried by said bracket means for guiding engagement with said guide surface.

4. In combination with a rotatable mandrel for winding a member fed thereto to form a coil thereof, a device for feeding said member to said mandrel and for tensioning it during such feed-ing, said device comprising a stationary shaft disposed in parallel with said mandrel, a pair of frame members carried by said stationary shaft, said frame members extending generally radially fromn said stationary shaft and being angularly and axially freely movable relative thereto, a mounting member extending angularly from each frame member, a guide roller carried by each mounting member, means forming a guide surface for engagement by said guide rollers which extends in parallel with said stationary shaft, a pair of tensioning rollers one carried by each of said mounting members, said tensioning rollers forming a channel for the passage of said member to said mandrel, and a roller journalied on said stationary shaft between said frame members for guiding said member on its passage from said tensioning rollers to said mandrel.

5. The structure and combination defined in claim 4, together with a holder for each tension-ing roller, means for firmly securing one of said holders in connection with one of said mounting members, means for pivotally securing the other holder in connection with the other mounting member, and spring-controlled means for re-siliently adjustably interconnecting said holders.

6. The structure and combination defined in claim 4, together with a roller journafled between said frame members at the free end thereof for connection with the roller journalled on said stationary shaft between said frame members to guide said member on its passage to said mandrel.

7. in combination with a rotatable mandrel for winding a member fed thereto to form a coil thereof, a device for feeding said n ieniber to said mandrel and for tensioning it during such feed-ing, said device comprising a stationary shaft disposed in parallel with said mandrel, a pair of frame members pivotally secured to said stag tionary shaft and generally radially extending therefrom for substantially unimpeded angular and longitudinal displacement relative thereto, a mounting member depending from each frame member, a guide roller carried by each mounting member at the free end thereof, means forming a guide surface for engagement by said guide rollers which is disposed underneath said stationary shaft and which extends in parallel there-with, a bracket carried by each mounting mem-1J ber, a first holder relatively firmly secured to one of said brackets and depending therefrom, a second holder pivotally secured to the other bracket and depending therefrom, a tensioning roller carried by each holder at the free end thereof, said tensioning rollers forming a channel for the passage of said member to said mandrel, and means associated with said holders for resiliently adjustably biasing said pivotally secured holder with respect to said firmly secured holder to press said tensioning rollers against said member during passage thereof through the channel formed thereby.

8. The structure and combination defined in claim 7, together with a roller journalled rotata-bly between said frame members to guide said member on its passage from said tensioning rollers to said mandrel.

9. In combination with a rotatable mandrel for winding a member fed thereto to form a coil thereof, a device for feeding said member to said mandrel and for tensioning it during feeding, said device comprising a pair of frame members disposed in spaced parallel relationship, means for mounting said frame members for substantially unimpeded displacement longitudinally and angularly relative to said mandrel, means forming a guide surface extending in parallel with the axis of said mandrel, a guide roller associated with said frame members for engagement with g5 said guide surface to guide the displacement of said frame members longitudinally relative to said mandrel, a holder extending from each frame member, and a tensioning roller carried by each holder for coacting pressure engagement with said member on its passage to said mandrel, the axes of said tensioning rollers being disposed perpendicular to the axis of said mandrel.

10. The structure and combination defined in claim 9, together with a freely rotatable roller disposed between said frame members for guiding said member on its passage from said tensioning rollers to said mandrel, the axis of said roller extending in parallel with the axis of said mandrel. JAMES E. BOSH, REFERENCES CITED The following referenuces are of record in the file of this patent: Hl :_ H UNIT.W ST1Al' s k'T_ N'' Number Namie mate 1,139,872 James-----------__May 18, 1915 1,797,331 Jpale------------__Mar. 24, 1931 2,021,276 Weinhart---------__Nov. 19, 1935