US2157050A

US2157050A - Igniter coil manufacture

Info

Publication number: US2157050A
Application number: US160046A
Authority: US
Inventors: Henry W Bilger; Karl T Kessel
Original assignee: Cuno Engineered Products Inc
Current assignee: Cuno Engineered Products Inc
Priority date: 1937-08-20
Filing date: 1937-08-20
Publication date: 1939-05-02
Anticipated expiration: 1956-05-02

Description

1939- H w. BILGER ET AL IGNITER COIL MANUFACTURE Filed Aug. 20, 1937 INVENTORS Patented May 2, 1939 rom'rnn con. MANUFACTURE Henry w. Bilger and Karl 'r. Kessel, Meriden,

Conn., assignors to The Cuno Engineering Corporation, Meriden', ml" a corporation of Connecticut "Application August 20, 1937, Serial No. 160,046

. v 6 Claims. (Cl. 29-1555) Our invention relates to a method and means for forming a resistance coil for cigar lighters and the like and especially coils of flat wire or ribbon wound in spiral form.

These coils "are commonly formed by winding the ribbon on a hand operated, hand controlled or automatic machine in which the wire is fed onto a mandrel of proper diameter to form the central turn. The ribbon is then wound coil upon 10 coil to form a spiral with all of the turns substantially in one plane. Qne disadvantage of this method is that it requires wire of a definite temper so that the coil is wound and released the normal spring of the wire is suficient to cause 15 the turns to space themselves from one another so as to prevent short circuiting. Another disadvantage of this method is that when the wire has sufiicient temper to properly space itself when released after winding and the twoends of the 20 coil are fixed to rigid-conducting members in the assembled heating unit, the coils when heated,

as in use, tend to shift somewhat and they leecome annealed into irregular relation with respect to one another. Some of the coils are too too far apart.

We have sought to provide a method of manufacture which will obviate these difdculties and produce a coil the turns of which will be uniformly 3 spaced.

For this purpose we provide an arbor, the end of which is approximately conical but provided with steps arrangedin the form of a combined helix and spiral. We use a dead soft or an- 35 nealed wire or ribbon. Since this has no itendency to spring it takes and retains the size and spacing given it on the arbor and no shifting of coils takes place when heated in use. As these coils are usually flat or only slightly convex,

40 we bring the helico spiral coil into the flat or substantially fiat form by compressing it between dies. The-resulting coil is a substantially fiat spiral of regularity and uniformity and its form is held I indefinitely in use.

45 Fig. 1 is an enlarged side view of the arbor showing acoil in section formed upon it.

Fig. 2 is an end view 01 the arbor.

Fig. 3 is v a fragmentary section on a much enclose and tend to short circuit and others are in the terminal or contact cup of an igniter element. v

Fig. 7 is a perspective view of "a fragment of the. 'end of the ribbon to form the central part of the coik. The mandrel or arbor 8 is formed of suitable metal and adapted to be rotated in a suitable type lathe etc. The end 9 of the arbor is in general conical and provided with a series of steps increasing in'diameter spirally and progressing ax- 10 ially at the same time at a uniform pitch.

The ribbon in has its tip ll bent overat an angle to fit in the slot E2 in the extreme end of the arbor. The central part it of the arbor may be formed separately from a rod and insorted and held adjustable in the body of the arbor. At each turn of the steps the radiusincreases by the amount it enough more than the thickness of the ribbon to allow for the space required between adjacent turns of the ribbon in the -finished. coil. The axial width id of each step is less than the Width of the ribbon so that each turn overlaps the preceding turn as shown in Fig. 3. This makes it mucheasier to flatten or collapse the coil to the position of Figs. 4 and 6.

The ribbon or fiat wire is made dead soft or highly annealed so that when the arbor is rotated the ribbon will lie smoothly upon the helicov spiral steps. As the wire has no resiliency or tendency to spring, it takes and retains its shape with the size and spacing of the turns determined by steps on the arbor on which it is wound.

If the coil is to be made more shallow axially it is a simple matter to shape it between dies to the slightly convex or concave form shown in Fig. 4.

' The greatest number of cigar lighter coils are substantially fiat as shown in Fig. 6 which form is fixed by setting the coil in a press or between 40 flat dies.

These coils are used in shallow cups it such as shown in Figs. 5 and 6. The outer end of the coil is usually welded to the inner wall of the cup and the inner end of the coil is secured by welding, brazing, riveting, etc. in the central stud ll of the igniter element.

As the wire ribbon isv completely annealed before, the coil is formed, no shifting of the coils' takes place when the device is heated in use.

The coil produced in this way is much more uniform in turns and 'in spacing than those formed in any other known manner.

The use of a cup type receptacle of the general shape indicated on the drawing is of advantage to in its assistance in holding the coil in position before the welding operation. As shown in the drawing the radial separation of the convolutions of the finished coil is substantially uniform and not greater than about twicethe thickness of the metal ribbon.

We claim: y

l. The method of making an igniter coil which comprises winding a flat ribbon into a helicospiral form with each convolution partially overlapping the preceding convolution in an axial direction and spaced radially therefrom and then pressing and thereby permanently setting all convolutions in a substantially common plane.

2. The method of forming an igniter coil which compriseswinding a dead soft ribbon of metal upon an arbor having a helicoidal step, the width of the step axially of the arbor being less than the width of the ribbon and the height of the step radially'of the arbor axis being greater than the thickness of the ribbon and then pressing and thereby permanently setting all of the convolutions of the coil into approximately the same general plane. l

3. The method of forming a spiral resistance coil having a plurality of spaced convolutions, which comprises winding a soft fiat strip of resistance wire on a stepped conical arbor beginning near the axis and gradually increasing in diameter, each succeeding convolution being spaced from but partially overlapping the next inner convolution, then removing the coil from the arbor and compressing the coil between dies and thereby permanently setting the convolutions into a substantially common plane.

4. The process of making an ignition coil for al, removing the coil from said arbor by relative translation therebetween, shortening the axial length of said coil by pressure applied in the general direction of the 'coil axis.

5. The process of forming a cigar lighter heating coil which comprises winding substantially flat dead soft electric resistance ribbon on. an

arbor provided with substantially fiat steps of approximately uniform height and of roughly v not more than abouttwice the thickness of the ribbon to form a conical helical coil with the convolutions radially spaced, removing the entire coil from the arbor without substantially expanding or contracting the convolutions, by relative translation between the arbor and all coni volutions of the coil.

6. The process of forming a generallyspiral heating coil for a cigar lighter which includes winding soft fiat electric resistance. metal into a conical helical form with the convolutions radially spaced, compressing the coil in the general direction of its axis to very substantially shorten the axial length of the coil by pressure applied to the side edges of the metal until the side edges of the convolutions and the inner end of the metal are substantially alined from the center of the coil outwardly.

HENRY W. BILGER. KARL T. KESSEL.