US3789480A

US3789480A - Method of and apparatus for applying insulating discs to conductors

Info

Publication number: US3789480A
Application number: US00225100A
Authority: US
Inventors: R Iyengar; B Zuber
Original assignee: Northern Electric Co Ltd
Current assignee: Nortel Networks Ltd
Priority date: 1971-11-29
Filing date: 1972-02-10
Publication date: 1974-02-05
Anticipated expiration: 1991-02-05
Also published as: CA956442A

Abstract

A method of and apparatus for applying insulating discs upon a continuously advancing conductor comprises advancing a continuous chain of discs towards a disc applicator station. First and second means carried by an applicator wheel sever individual discs from said chain and advance the discs along a predetermined path. Slitting means mounted in said predetermined path impart a slit to the disc and an arcuate guide member extending from the slitting means to the conductor enters the slit in the disc and gradually expands the slit to facilitate application of the disc upon the conductor.

Description

United States Patent Iyengar et al. Feb. 5, 1974 METHOD OF AND APPARATUS FOR 2,544,280 3/1951 Sabine 29/203 c APP INSULATING DISCS o 2,677,879 5/1954 Beueridge 29/203 C 2,579,487 12/1951 Frankwich 29/203 C CONDUCTORS 3,002,547 /1961 Cootes 29/200 X [75] Inventors: Rama Iyengar, Dollard des 3,051,213 8/1962 Batcheller... 29/200 8 X ormeaux Quebec; Brefislay Paul 3,070,144 12/1962 Evans 29/200 B X zuber, Montreal, Quebec both of 3,348,286 10/1967 Busler 29/203 D Canada 73 A z N "h El t C d, Primary Examiner-Charles W. Lanham sslgnee g; f gg 32:23: mu e Assistant Examiner-Joseph A. Walkowski, Jr.

Attorney, Agent, or Firm-Philip T. Erickson [22] Filed: Feb. 10, 1972 [21] Appl. No.: 225,100 ABSTRACT Foreign Application Priority Data A method of and apparatus for pp y insulating Nov 29 I97] Canada 128860 discs upon a continuously advancing conductor comprises advancing a continuous chain of discs towards a l 52] U S Cl 29/203 C 29,624 174/28 disc applicator station. First and second means carried 333/96 by an applicator wheel sever individual discs from said [51] In C H0") 13/20 chain and advance the discs along a predetermined [58] Field of search29/203'C 1935 P 200 D path. Slitting means mounted in said predetermined 29/200 P 624, 156/47 264/138 path impart a slit to the disc and an arcuate guide 1 1 174/28 3 3 l9 member extending from the slitting means to the conductor enters the slit in the disc and gradually expands [56] References Cited the slit to facilitate application of the disc upon the conductor.

15 Claims, 7 Drawing Figures Patented Feb. 5, 1974 (i Shoots-Sheet 1 E 5 a 5 r Patented Feb. 5, 1974 6 Sheets-Sh g 6 Sheets-Sheet 3 Patented Feb. 5, 1974 6 Sheets-$heet L FIG. 4

Patented Feb. 5, 1974 6 Sheets-Sheet 5 Hll (III! Patented Feb. 5, 1974 6 Sheets-Sheet 6 METHOD OF AND APPARATUS FOR APPLYING INSULATING DISCS TO CONDUCTORS This invention relates to a method of and apparatus for feeding and applying insulating discs in spaced relationship on a central conductor in the manufacture of a coaxial cable.

A coaxial cable usually comprises a solid conductor centrally spaced within a tubular outer conductor by means of wafer-like spacing and insulating discs. Various methods and apparatus have been used in the past for applying the insulating discs to such a cable. One such way consisted of moulding plastic discs directly on the central conductor. This method required complicated and expensive apparatus and production speeds were usually very slow.

Another method of making such a cable is described in Canadian patent 488,046 which issued 11 Nov. 1952 to Samuel E. Brillhart, wherein individual discs are gravity fed through guide chutes from hoppers to transfer devices. The transfer devices move the discs into oriented positions in notches formed in the applicator wheels which in turn advance the discs over knives positioned to slit the discs radially. The discs then pass over guides which enter the slit in the discs and keep it open. The applicator wheels then move the discs from the guides onto the central conductor with a wiping action.

One of the major difficulties encountered with methods and apparatus heretofore known has been the handling of the discs from the time they were fed from the hopper to the time they were placed on the conductor. In order to feed the discs through a guide chute in an oriented position, the hopper was usually agitated. Sometimes the discs were agitated so much that they acquired static charges which prevented them from feeding freely through the guide chutes. The problem of maintaining the discs in an oriented position created difficulties because they sometimes became displaced from their position in notches in the applicator wheel and consequently when they were advanced over the slitting knife, the knife formed non-radial slits therein. This prevented proper application of the discs onto the central conductor and usually caused tie-ups in the apparatus. Such tie-ups or jams required stopping the whole apparatus for forming the cable with which the disc feeding, slitting and applying devices are associated.

In order to overcome these difficulties, it was necessary to provide improved means for feeding discs to an applicator wheel, means for maintaining the discs in an oriented position, means for cutting radial slits in the discs, means for holding the slits open so that the central conductor may be passed therethrough into the central aperture without damaging the discs and means for applying the discs to the central conductor with a wiping action.

The present invention resides in a method of and apparatus for handling discs joined together in continuous chains rather than in loose form as in the prior art. The chains of discs are fed to applicator wheels which sever the discs from the chains, pass them over knife edges which form and open radial slits therein, and then position the discs on an advancing conductor at spaced intervals.

A clear understanding of the invention may be had from the following description of an apparatus and a method of a particular embodiment thereof when read in conjunction with the accompanying drawings, in which:

FIG. 1 is a perspective view of an apparatus for applying insulating discs to a conductor in accordance with the present invention;

FIG. 2 is an enlarged, fragmentary sectional view taken along line 22 of FIG. 1;

FIG. 3 is an enlarged, fragmentary view in perspective taken along line 3-3 of FIG. 1 showing the steps of cutting, slitting, expanding and advancing the disc to the conductor;

FIG. 4 is a side elevation view of the apparatus of FIG. 1, part of the base being broken away to illustrate the synchronized driving mechanism;

FIG. 5 is a front elevation view of the apparatus of FIG. 1, part of the base being broken away to further illustrate the synchronized driving mechanism;

FIG. 6 is an enlarged view in perspective of a continuous chain of discs employed in the practice of the present invention; and

FIG. 7 is an enlarged view in perspective of a disc insulated conductor made in accordance with the present invention.

Referring to the drawings, FIG. 1 shows an apparatus for cutting individual discs 10 from a continuous chain of discs 12 and applying them at uniform intervals on a continuously advancing conductor. The apparatus comprises a vertically fed chain of discs and a disc applicator disposed on either side of an advancing horizontal conductor. For purposes of clarity, only one side will be described in detail. It is to be understood, however, that the discs applied to the conductor emanate alternatively from either side.

A chain of discs 12 is fed from a supply spool (not shown) through a set of pressure rolls l6 and 18. Roll 16 is rigidly mounted to shaft 20 by means of nut 22; shaft 20 being rotatably mounted in bearing housing 24 and projects therethrough as seen in FIG. 4. Bearing housing 24 is mounted on support plate 26 which is rigidly secured to main base member 28. A pulley 30 is affixed to the end of shaft 20 which extends rearward from support plate 26. Shaft 20 is belt driven from a main drive shaft 90. This feature is described below. At the front end of bearing housing 24 there is rigidly mounted an auxiliary bracket 32 to which is pivotly mounted a free rolling roll 18 by means of a pivot arm 34 and a pin 36. The free rolling roll 18 is spring loaded by means of a compression spring 38 mounted on a tie rod 40 rigidly secured at one end to bracket 32 by means ofanchor 42, the spring being secured against pivot arm 34 by means of a nut 44 to provide pressure of roll 18 against roll 16 in the direction of arrow 46 as seen in FIG. 5. Nut 44 also serves to adjust the pressure of roll 18 against roll 16. In order to enhance the alignment of the chain of discs 12 as it is fed between the rolls, roll 16 may be provided with a groove 48, the width of the groove being substantially the same as the width of the chain 12 and the depth being slightly less than the thickness of a disc.

Driven roll 16 in conjunction with pressure roll 18 advances chain 12 through a guide chute 50 which is mounted to a base plate 52 directly below and in alignment with groove 48 in roll 16 until the chain reaches a stopper block 54 (see FIG. 3).

The chain of discs 12 comprises a series of discs 10 joined together in coplanar fashion as shown in FIG. 6.

Such a chain may be punched from a strip of suitable material, such as polyethylene, and wound on spools. Each disc is provided with a central aperture 13, the size of which is substantially the same or slightly smaller in diameter than that of the conductor 14 upon which it is to be applied. As a result, conductor 14 tends to spread open slits 13 in discs 10, as is shown in FIG. 7. The natural resiliency of the discs causes them to' firmly engage the conductor.

A disc applicator wheel 56 is rotatably mounted on the platen 58 of main base member 28 and is provided with a series of knives 60 and retaining teeth 62 mounted at the periphery of applicator wheel 56. As can be seen in FIGS. 1 and 4 applicator wheel 56 is rigidly mounted to a shaft 66 by means of a nut 68, the description of the shaft portion on the underside of platen 58 is described below.

Knives 60 are secured to the periphery of wheel 56 and are positioned thereon such that they extend into the path of chain 12. Retaining teeth 62 are secured to the periphery of wheel 56 and are disposed such that each tooth 62 is adjacent to and immediately behind each knife 60. Teeth 62 are provided with a groove 64 (see FIG. 3) to permit passage of the teeth over a knife edge and guide in the arcuate path of the teeth as well as over conductor 14 when the disc is wiped thereon.

As applicator wheel 56 rotates in the direction of arrow 70, knife edge 60 is passed through the chain of discs 12 and one disc 10 is severed therefrom. A guard 61, mounted at the bottom of guide chute 50 prevents the severed disc 10 from being twisted out of orientation due to the severing action of knife edge 60. The disc 10 is then advanced facewise by means of retaining tooth 62, past a knife edge 72 where a slit 74 is imparted thereto (see FIG. 3). Knife edge 72 is mounted to the leading edge of an arcuate guide 75 having a gradually increasing thickness, knife edge 72 being mounted in a predetermined path to cause slit 74 to be imparted to one-half of the disc 10, for example from the central aperture 13 to the outer periphery thereof. The arcuate guide 75 extends from knife edge 72 to a point tangent with central conductor 14 and it is preferred that the thickness of the guide 75 at the tangent point be at least as thick as the diameter of the conductor 14 upon which the discs 10 are being applied.

The slit disc 10 is advanced over the arcuate guide 75 and slit 74 is gradually opened until it reaches the end of the guide and is wiped onto advancing conductor 14 at uniformly spaced intervals by means of retaining tooth 62. This allows conductor 14 to enter slit 74 readily and to slide easily through the slit into central aperture 13 of the disc. Since arcuate guide 75 terminates at a point adjacent conductor 14, slit 74 is released as the disc is applied and is free to close about and substantially surround the conductor in the manner shown in FIG. 7. The natural resiliency of disc 10 causes it to engage conductor 14 firmly and ensures the retention of the disc in its proper place on the conductor.

After receiving discs 10, conductor 14 is guided by guide pulleys 76 and 76' rotatably mounted on platen 58.

Pulleys

76 and 76 are secured a predetermined distance apart by means of

nuts

80 and 80 on shafts 78 and 78', respectively.

Shafts

78 and 78 are mounted in bearing housings 82and 82', respectively, (see FIG. 5)

which in turn are secured to the underside of platen 58.

As seen in FIG. 1, pulleys 76 and 76' are provided with teeth 84 and 84' equally disposed about the periphery of each pulley. The size of teeth 84 and 84' is equal to at least one-half the diameter of a disc 10, with the spacing between consecutive teeth slightly more than the thickness of a disc 10. The width of these teeth must not be greater than the distance between any two discs 10 after they have been placed on conductor 14. Since the purpose of

pulleys

76 and 76 is to guide central conductor 14, as well as preventing any lateral movement thereof, they are securely and specifically placed to accomplish this end. In the preferred embodiments,

teeth

84 and 84 are provided with semicircular grooves 88 and 88' to further control the path of conductor 14. The diameters of grooves 88 and 88' are substantially equal to the diameter of conductor 14. In operation, the entire apparatus is synchronized by means of a combination gear and belt drive mechanism. A typical dirving mechanism is shown in FIGS. 4 and 5. In FIG. 4, a main drive shaft 90 driven by a single motor (not shown), is rotatably mounted in a main bearing housing 92 rigidly secured to base member 28. A drive pulley 94 is secured to shaft 90 and a belt drive 96 connects

pulleys

94, 30 and 30' respectively, to drive pressure rolls l6 and 16'. A miter gear 98 is secured to the interal end of shaft 90 and engages a second miter gear 100 securely mounted to shaft 66. The synchronized rotation of applicator wheels 56 and 56' is obtained by means of meshing

spur gears

102 and 102 mounted on

shafts

66 and 66, respectively. Pulleys 76 and 76' are synchronized by means of meshing

spur gears

104 and 104 respectively mounted to shafts 78 and 78'. Synchronized rotation of

pulleys

76 and 76 with

applicator wheels

56 and 56 is assured by means of a belt drive 106 linking

shafts

78 and 66 respectively.

Since discs 10 are applied to conductor 14 alternately from opposite sides, retaining teeth 62-62', which advance the discs over arcuate guide 75 when applicator wheels 56-56 are rotated, are arranged so that when one of the discs 10 is being forced onto conductor 14 by a tooth 62 on applicator wheel 56, a tooth 62 on applicator wheel 56' picks up a disc 10 as it is being severed from chain 12.

. Similarly, pulleys 76-76 are preset such that tooth elements 84-84 are aligned one with respect to the other. In this manner, the tooth elements will guide conductor 14 at the spaces between the discs 10 mounted thereon. Likewise, as a disc on the conductor approaches the pulleys, it will be located in spaces 86-86 between tooth elements 84-84 as clearly shown in FIG. 1.

Although with the present apparatus it is preferred to slit the discs as they are advanced toward the conductor, it may be advantageous to slit the discs while they are in a continuous chain. The slits could then easily be opened by means of an arcuate guide placed in the path of the advancing disc after it has been severed from the chain. It may also be advantageous to use more than one such apparatus in tandem to provide increased speed in the application of the discs 10 to conductor 14.

What is claimed is:

1. An apparatus for placing insulating discs at intervals on a continuously advancing conductor comprising:

rotatable feed means for advancing individual discs in succession along an arcuate path to the conductor from a location spaced therefrom and for placing the discs on the conductor,

means for advancing a continuous chain of discs to said location,

means carried by said rotatable feed means for severing individual discs from said chain of discs; and means for opening a slit in each disc as it is advanced toward the conductor from said location.

2. An apparatus as defined in claim 1 wherein said means for opening a slit in each disc comprises a knife edge mounted at a predetermined point in the path of the disc as it is being advanced towards the conductor.

3. An apparatus as defined in claim 2 further comprising guide means adjacent said knife edge for entering the slit to keep it open and to guide the disc,

said guide means extending from the knife edge substantially to the conductor to facilitate placement of the disc on the conductor by means of the slit.

4. An apparatus as defined in claim 3 wherein said guide means is tapered outwardly from the end adjacent the knife edge to the other end and serving to gradually open the slit in the disc as the disc is advanced over the guide.

5. An apparatus as defined in claim 4 wherein said means for advancing the severed discs comprises a rotatable feed wheel positioned with one portion of the periphery thereof adjacent said location where the individual discs are severed from the chain of discs and with another portion of the periphery adjacent the-path of the advancing conductor, said feed wheel having at least one disc retaining means at the periphery thereof for transporting severed discs individually from said location to the conductor, said guide means extending arcuately along the periphery of said feed wheel.

6. An apparatus as defined in claim 5 wherein said means for severing individual discs from said chain of discs comprises a knife edge mounted at the periphery of said feed wheeljust in advance of each said retaining means in the direction of rotation of said feed wheel.

7. An apparatus as defined in claim 6 wherein said retaining means comprises a retaining tooth mounted on the periphery of said feed wheel,

said retaining tooth being grooved to permit passage over said guide means while advancing the disc to the conductor.

8. An apparatus as defined in claim 1 wherein said means for advancing the chain of discs toward a disc applying station comprises:

means for guiding the chain of discs toward said location where individual discs are severed therefrom, and

pressure roller means for urging the chain of discs along said guiding means.

9. An apparatus as defined in claim 8 wherein said guiding means comprises a channel member having a stop at said location where the individual discs are severed from the chain, and said pressure roller means comprises a constantly rotating drive roller and a pressure roller resiliently urged toward the drive roller to releasably grip the chain of discs therebetween whereby the chain is advanced by the drive roller until thelead disc thereof engages the stop of the channel member whereupon the chain of discs ceases to advance and the drive roller rotates slidably thereagainst until said lead disc is severed and removed from the chain of discs which again advances under the influence of the drive roller.

10. An apparatus as defined in claim 9 wherein said means for advancing the severed discs comprises a rotatable feed wheel positioned with one portion of the periphery thereof adjacent said location where the individual discs are severed from the chain of discs and with another portion of the periphery adjacent the path of the advancing conductor, said feed wheel having at least one disc retaining means at the periphery thereof for transporting severed discs individually from said location to the conductor, said means for severing individual discs successively from said chain of discs comprising a knife edge mounted at the periphery of said feed wheel just in advance of each said disc retaining means in the direction of rotation of said feed wheel.

11. An apparatus as defined in claim 10 wherein said means for opening a slit in each disc comprises a knife edge mounted at a predetermined point in the path of the disc as it is being advanced towards the conductor.

12. An apparatus as defined in claim 11 further comprising guide means adjacent said knife edge for entering the slit to keep it open and to guide the disc,

13. An apparatus as defined in claim 12 wherein said guide means is tapered outwardly from the end adjacent the knife edge to the other end and serving to gradually open the slit in the disc as the disc is advanced over the guide.

14. An apparatus as defined in claim 13 wherein said retaining means comprises a retaining tooth mounted on the periphery of said feed wheel,

15. An apparatus for placing insulating discs at intervals on a continuously advancing conductor comprising:

means for advancing a continuous chian of discs toward a disc applying station,

means for severing individual discs from said chain of discs at a location spaced from the path of said advancing conductor,

means for advancing the severed discs in succession from said location to the conductor and for placing the discs thereon comprising a rotatable feed wheel positioned with one portion of the periphery thereof adjacent said location where the individual discs are severed and with another portion of the periphery adjacent the path of the advancing conductor, and

means for opening a slit in each disc as it is advanced toward the conductor from said location,

said feed wheel having at least one disc retaining means at the periphery thereof for transporting severed discs individually from said location to the at the periphery of said feed wheel just in advance conductor, of each said disc retaining means in the direction said means for severing individual discs successively of rotation of said feed wheel. from said chain comprising a knife edge mounted

Claims

1. An apparatus for placing insulating discs at intervals on a continuously advancing conductor comprising: rotatable feed means for advancing individual discs in succession along an arcuate path to the conductor from a location spaced therefrom and for placing the discs on the conductor, means for advancing a continuous chain of discs to said location, means carried by said rotatable feed means for severing individual discs from said chain of discs; and means for opening a slit in each disc as it is advanced toward the conductor from said location.

3. An apparatus as defined in claim 2 further comprising guide means adjacent said knife edge for entering the slit to keep it open and to guide the disc, said guide means extending from the knife edge sUbstantially to the conductor to facilitate placement of the disc on the conductor by means of the slit.

5. An apparatus as defined in claim 4 wherein said means for advancing the severed discs comprises a rotatable feed wheel positioned with one portion of the periphery thereof adjacent said location where the individual discs are severed from the chain of discs and with another portion of the periphery adjacent the path of the advancing conductor, said feed wheel having at least one disc retaining means at the periphery thereof for transporting severed discs individually from said location to the conductor, said guide means extending arcuately along the periphery of said feed wheel.

6. An apparatus as defined in claim 5 wherein said means for severing individual discs from said chain of discs comprises a knife edge mounted at the periphery of said feed wheel just in advance of each said retaining means in the direction of rotation of said feed wheel.

7. An apparatus as defined in claim 6 wherein said retaining means comprises a retaining tooth mounted on the periphery of said feed wheel, said retaining tooth being grooved to permit passage over said guide means while advancing the disc to the conductor.

8. An apparatus as defined in claim 1 wherein said means for advancing the chain of discs toward a disc applying station comprises: means for guiding the chain of discs toward said location where individual discs are severed therefrom, and pressure roller means for urging the chain of discs along said guiding means.

9. An apparatus as defined in claim 8 wherein said guiding means comprises a channel member having a stop at said location where the individual discs are severed from the chain, and said pressure roller means comprises a constantly rotating drive roller and a pressure roller resiliently urged toward the drive roller to releasably grip the chain of discs therebetween whereby the chain is advanced by the drive roller until the lead disc thereof engages the stop of the channel member whereupon the chain of discs ceases to advance and the drive roller rotates slidably thereagainst until said lead disc is severed and removed from the chain of discs which again advances under the influence of the drive roller.

12. An apparatus as defined in claim 11 further comprising guide means adjacent said knife edge for entering the slit to keep it open and to guide the disc, said guide means extending from the knife edge substantially to the conductor to facilitate placement of the disc on the conductor by means of the slit.

14. An apparatus as defined in claim 13 wherein said retaining means comprises a retaining tooth mounted on the periphery of said feed wheel, said retaining tooth being grooved to permit passage over said guide means while advancing the disc to the conductor.

15. An apparatus for placing insulating discs at intervals on a continuously advancing conductor comprising: means for advancing a continuous chian of discs toward a disc applying station, means for severing individual discs from said chain of discs at a location spaced from the path of said advancing conductor, means for advancing the severed discs in succession from said location to the conductor and for placing the discs thereon comprising a rotatable feed wheel positioned with one portion of the periphery thereof adjacent said location where the individual discs are severed and with another portion of the periphery adjacent the path of the advancing conductor, and means for opening a slit in each disc as it is advanced toward the conductor from said location, said feed wheel having at least one disc retaining means at the periphery thereof for transporting severed discs individually from said location to the conductor, said means for severing individual discs successively from said chain comprising a knife edge mounted at the periphery of said feed wheel just in advance of each said disc retaining means in the direction of rotation of said feed wheel.