US2909209A - Apparatus for making helical electric resistance heating wire coils and provided with a rotary mandrel and a pressing roll having an elastically deformable coil embracing surface - Google Patents

Description

20, 1959 P. CICCONE ETAL 2,909,209

APPARATUS FOR MAKING HELICAL ELECTRIC RESISTANCE HEATING WIRE COILS AND PROVIDED WITH A ROTARY MANDREL AND A PRESSING ROLL HAVING AN ELASTICALLY DEFORMABLE COIL EMBRACING SURFACE Filed May 24 1954 g 6% 5 m f APPARATUS FOR MAKING HELICAL ELECTRIC RESISTANCE HEATING WIRE COILS AND PRO- VIDED WITH A ROTARY MANDREL AND A PRESSING ROLL HAVING AN ELASTICALLY DEFORMABLE COIL EMBRACING SURFACE Patsy Ciccone, Cranford, and William WalterWallin, Kearny, NJ., assignors to Driver-Harris Company, Harrison, N.J., a corporation of New Jersey Application May 24, 1954, Serial No. 431,791

1 Claim. c1. ass-s4 gauges of wire, such as 30 B. &- S. gauge, in an automatic manner with the resulting coils having their convolutions strained so uniformly that when a coil is pulled apart or extended longitudinally each convolution separates from the other substantially equal amounts throughout the coils length. This is important because such coils are frequently operated very close to their melting temperatures and if two adjacent convolutions fail to separate as much as the others, these convolutions overheat and result in destruction of the coil as a useful heating element. For a similar reason it is important that the wire be coiled without nicking it or otherwise locally reducing its diameter.

Such automatic wire coiling became possible because of the development of the invention disclosed and claimed by the Stephen A. Platt application Serial No. 251,053, filed October 12, 195 1, and now abandoned. A machine constructed in accordance with the said Platt invention features a rotatively powered rotary mandrel having a smooth cylindrical surface terminating with a free end. Means are provided for feeding wire transversely to a portion of the mandrels surface spaced from its free end and at least one rotary roller is provided which has a free end extending in the direction of the mandrels free end and having a peripheral surface positioned to bear in a rolling manner on thewire when it is helically wound on the mandrels mentioned portion; This rolling surface is contoured so as to be spaced free from the mandrel when bearing on the wire wound thereon and the surface of this roller, like that of the mandrel, extends in an axially smooth fashion to the rollers free end. The wire is coated with a liquid lubricant and is wet with this lubricant while it is wound on the mandrel, the desired helicalcoil growing from its point of feed and sliding therefrom axially past the free ends of the mandrel and roller and away therefrom as a continuously traveling coil. At least one other rotary roller provides a rigid rotary abutment surface extending radially.

with respect to the mandrel and located adjacent to the end of the mandrel portion carrying the convolutions which is most remote from the mandrels free end; This abutment surface is arranged to abut the first of the convolutions formed by the wire fed to this mandrel portion, whereby to prevent the coil from backing up oppositely to the growing direction of the coil.

Due to the above arrangement the rollers and mandrel may be rotated at different relative speeds and this to gether with the use of liquid lubrication and the other contributing features has permitted the coiling of electric resistance wire coils when using wire gauges down to the 30 B. & S. gauge mentioned.

J Un d St f P re MC? In the case of finer wires these automatic coiling ma chines have experienced operational troubles. In some instances such fine wire could be coiled but the machine. could be set up initially only with considerable difficultyl These machines are familiar to everyone skilled in the coiling of electric resistance heating wire coils and, as is. well known, they must be adjusted by varying roller angularities, roller speeds and pressures, as related'to the mandrel and the wire coiling thereon, and the like. These usual adjustments have been very ditficult or impossible to make in the case of very fine wirecoiling.

One of the objects of the present invention is to prove on the machines incorporating said Platt invention of the mentioned application, in such a fashion as to' permit that type of machine to be satisfactorily used in the case of the very fine wire gauges. Another, object is to provide a method of Wire coiling permitting the coiling of helical coils from such fine gauge wire. The present invention has commercially proven itself to be fully capable of satisfactorily attaining these objectives;

The accompanying drawings illustrate a specific ex-,

. ample of the described kind of wire coiling machine which has been improved by the incorporation of the present invention, the various figures being as follows:

Fig. 1 is an end elevation showing the end of the machine away from which the coil feeds;

Fig. 2 is a top view of the machine;

Fig. 3 is an enlarged view showing the coiling action; Fig. 4 is a horizontal section taken centrally through Fig. 3; and

Fig. 5 shows an important element used in connection T with the improvement.

. maintained in a pan 19. This coats the entire surface These drawings are somewhat schematic in character and they show a rotating chuck 1 which extends through. a housing 2 to an external pulley 3 which may be connected by a belt to an electric motor. The shaft mounting the chuck 1 is journaled in the housing 2 so as to rotate very smoothly. The described mandrel 4 is gripped by the chuck 1 and extends forwardly therefrom in an axially smooth manner and so as to terminate with, the free end 5. The usual two rollers 6 and 7 are journaled in brackets 8 and 9, respectively, these brackets having inwardly extending arms 10 and 11, respectively, which mount the brackets on a pivot 12. The weight of the rollers and of the arms causes outward motion but this weight is overbalanced, so that the rollers may be moved together, by a tension spring 13 provided with a tension adjusting screw 14. This spring extends trans versely so as to interconnect the two brackets 8 and 9.

These rollers are rotatively powered so as to turn in synchronous speeds, this being done through the flexible shafts 15 which extend through openings in the housing 2 and which are appropriately rotatively powered by equipment inside of the housing 2. The rotation of the shafts '15 and. hence of the rollers 6 and 7, is entirely independent of the mandrel 4 which is rotated by driving the pulley 3. Of course, the directions of rotation are such as to wind or coil the wire.

As iswell known to all commercial users of this kind of machine, the rollers 6 and 7 are constructed so as to mount various annular tools or rings which are used in connection with the coiling operation. I

The wire 16 is continuously drawn from an unillus trated supply reel downwardly and is bent around the bottom of a sheave 17 which is journaled so that its bottom runs beneath the level of a liquid lubricant 18' of the wire with the liquid lubricant, the wire then feeding upwardly and transversely on a portion of the spindle 4 which is spaced from the spindles free end 5.

Various liquid lubricants may be used, asoap and water solution, a water emulsion of a lubricating oil and;

Patented Oct. 20,

3 the like being suitable. Lubricants of this type are often used in the wire working art in general. This total or complete lubrication of the. wire has the advantage of causing the convolutions of the coil produced by the machine, to be uniformly strained was to get the desired kind of uniform extension when the coil is placed in. service. The lubrication prevents the formation of nicks. or other localized deformations such as might be caused, in the absence of the lubrication, because of the independence between the mandrel 4 and the rollers 6 and 7. The use of this lubrication is characteristic of the: describedtype of machine.

Heretofore the tools or rings used on the rollers 6 and 7 have been made of metal and, therefore, rigid.

This was thought to be necessary to obtain a proper drive on. the. wire during its coiling, the lubricated metal-tometal surfaces smoothly urging the wire to coil.

The present invention diverges from what was Previously known and uses an elastically deformable ring 20 which is mounted on the roller 6. This roller is connected to its shaft so as to be rotatively powered thereby. The surface of this roller is cylindrical and smooth, the surface, of course, terminating with a free end 21 extending in the direction of the free end 5. As is illustrated, the elastically deformable part is in the form of a tire 22 having a fiat, cylindrical tread forming the surface 20, and mounted firmly on a rigid supporting ring 23. This permits the unit to be mounted on the roller 6 in the usual manner. The elastic deforrnability should be sufficient to provide for a cushioning effect when acting on the coiled wire but it should not be so softly elastic as to contact the mandrel 4 by deforming or bulging, when the roller 6 has proper operating force or pressure applied to it by the spring 13. The elastic deformable ring 20 on the roller 6 is positioned in such a manner that the tire 22 extends beyond the rear of the first convolution. The forming of the first convolution is controlled by the rolling action of the elastically deformable ring 20 which partially embraces the rear side of the first convolution without contacting the mandrel (see Fig. 4).

The other roller 7 is provided with only the back-up ring 24 which prevents the helically coiled wire from backing up in a direction opposite to the growing direction of the coil. This ring provides a rigid rotary abutment surface 25 extending radially with respect to the mandrel 4 and located adjacent to the end of the mandrels portion to which the wire is transversely fed and which end is the one most remote from the mandrels free end. This ring 24 is arranged so that its surface 25 abuts the first of the convolutions formed by the wire fed to this portion of the mandrel and to thus prevent the coil from backing backwardly along the mandrel 4. Since the pan 19 containing the lubricant 18 is located so as to coat the wire before it reaches the surface '25, there is plenty of liquid lubricant between this wire and the surface at all times.

With this new improvement very fine gauge electric resistance heating wire may be helically coiled in the precision manner required for the reasons previously explained.

The wire 16 is fed transversely to the axially elongated rotating surface, provided by the mandrel 4, and is wound helically around this mandrel for a plurality of convolutions so as to form the helical coil, shown at 2-6 growing axially away from the location to which the Wire is transversely fed. The elastically deformable rotating surface 20 is pressed rollingly against the outside of the convolu tions so that the latter are radially engaged between the surfaces. Everything is soaked with slippery lubricant and it would ordinarily be supposed that rubber, deformable plastics, and other similar elastically deformable material such as must be used to provide the described type of surface, would be so slippery as to be ineffectiveas adriving element. However, actual practical experience has shown that a proper drive is easily effected.

The elastically deformable surface causes even fine wire to coil properly when gripped between the clastically deformable surface and the mandrel 4. Depending on the rotative speeds of the mandrel and of the elastic surface, the coil is more or less larger in diam eter than the mandrel 4. The rigidly positioned rigid surface 25 prevents the Wire coil from going backwards and forces it to grow or feed forwardly while sliding relative to the mandrel 4 and in many cases relative to the surface 20.

As the described kinds of machines are ordinarily constructed, the ring 24 will peripherally engage the mandrel 4 when used without a pressure rolling ring as is contemplated by the present invention. Because of the large amount of liquid lubrication existing everywhere throughout the coiling zone, this need not prevent the operation of the roller 7 at a peripheral speed different from that of the mandrel 4. In some instances the roller 7 may be unkeyed or disconnected so that it is not driven by its shaft 15. As shown by the drawings, the bracket 9 may be provided with an extension 27 which mounts an adjustable stop 28 which engages the housing '2 so as to space the periphery of the ring 24 from the mandrel 4 in the manner shown by Fig. 4.

It is to be noted that the present improvement permits the coiling of such fine wire so as to make satisfactory electric heating resistance coils because the wire is in effect spun on the mandrel 4 with the elastic surface 20 serving to hold the very fine wire more gently than before and while gently urging the wire to coil. As indicated, the tire 22 may be made of rubber or the like. Although everything is coated with liquid lubricant there is still sufficient drive, perhaps in a sliding or skidding manner, to urge the wire to coil. In any event, it is' a matter of fact that with the use of the present inven'-' tion it is now possible to automatically coil even finer gauge wire than could be handled by the machine made available to industry by the invention of the previously: mentioned Platt application. The coils produced have all the characteristics required for use as electric resistance heating coils and the coiling is carried out continuously and without interruptions once it has been started properly. It is to be understood that a suitable knife cuts the continuously growing coil into the desired lengths at the delivery end of the coiling machine.

As indicated, the mandrel and the deformable roll otfer substantially no impedance to the growing coil in its growing direction. The elastic surface deforms slightly but not so much as to contact the mandrel.

We claim:

A helical wire coil winding machine including a rotary mandrel having a free end, means for feeding wire transversely to a portion of the mandrels surface spaced from its said end, at least one rotary roller having a free end extending in the direction of the mandrels free end and having an elastically deformable peripheral surface positioned to bear in a rolling manner on at least the first convolution of the wire and extending rearwardly of said convolution as it is helically wound on the mandrels said portion, said elastically deformable surface being contoured so as to be spaced free from the mandrel when bearing on the wire wound thereon and to partially embrace the rear side of said convolution all of said surfaces extending to said free ends so that as the wire is continuously wound on the mandrels said portion the resulting helical coil growing thereon may slide therefrom axially past said free ends and away therefrom as a continuously traveling coil, and means for wetting the wire with liquid lubricant so that the wire is wet therewith while wound on said mandrel and While contacted by the rollers saidsurface, and at least one other rotary roller providing a rigid rotary abutment surface extending radially with respect to said mandrel. and located ad' 5 jacent to the end of the mandrels said portion most remote from the mandrels free end so as to abut said rear side of said first convolution formed by the wire fed to this portion and prevent the coil from backing up oppositely to the growing direction of the coil.

References Cited in the file of this patent UNITED STATES PATENTS 121,831 Weber Dec. 12, 1871 372,423 Mallet-Guy Nov. 1, 1887 1,243,179 James Oct. 16, 1917 1,953,502 Reimers Apr. 3, 1934

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