US3812443A

US3812443A - Stapled coil construction

Info

Publication number: US3812443A
Application number: US00363548A
Authority: US
Inventors: C Schroeder
Original assignee: Coilcraft Inc
Current assignee: Coilcraft Inc
Priority date: 1973-05-24
Filing date: 1973-05-24
Publication date: 1974-05-21
Anticipated expiration: 1991-05-21

Abstract

A coil assembly comprising a tubular coil form with a self-lead winding thereon, the leads of said winding extending axially beyond the end of the form, a sleeve telescopically inserted over the form and inside the leads at the end of lead extension, and staples securing the leads through the sleeve to the overlapped portion of the form, characterized by low cost and high versatility as to the pin circle described and the angular relation of the pins on the pin circle.

Description

United States Patent 11 1 Schroeder May 21, 1974 [5 STAPLED COIL CONSTRUCTION l,935.l69 11/1933 Williams 336/208 3,355,687 11/1967 Adams t 1 .1 336/192 X [751 m Charles schmedel" Cary 3,609,833 10/1971 Fry et a1. 336/192 x [73] Assigneet Conn-aft Inc" Cary, L 2,836,805 5/1958 Goldsmith 336/192 X 1 1 Filedi y 24, 1973 Primary Examiner-Thomas J. Kozma 1211 Appl. No.2 363,548

[57] ABSTRACT us. c1. 336 192 336 208 A coil assembly Comprising a tubular formfmh 1m. 01. 111111 1 s/10 self'lead Winding thereon the leads Ofsaid windmg Field of Search 336/192 198 20s tending axially beycmd the end 0f the form? a Sleeve telescopically inserted over the form and inside the [56 1 References cued leads at the end of lead extension, and staples securing UNITED STATES PATENTS the leads through the sleeve to the overlapped portion 7 I of the form, characterized by low cost and high versa- 22 35 tility as to the pin circle described and the angular re- 2:875:45) 2/1959 Hofer 6111131111111: I: 336/192 of the pm on the pm clrde' 3.355.688 11/1967 Adams 336/192 5 Claims, 7 Drawing Figures STAPLED COIL CONSTRUCTION BACKGROUND OF THE INVENTION Description of the Prior Art In U. S. Pat. No. 3,169,234 to Renskers dated Feb. 9, 1965, and U. S. Pat. No. 2,941,172 to Sutton dated June 14, 1960, there are shown self-lead coils mounted to fonnsconsisting of a tubular body with a flange at one end thereof. A helical self-lead winding or a winding of wire sufficiently stiff such that the ends of the wire can constitute the support of the coil and withstand the forces involved in inserting the coil into a printed circuit board, for instance, is deposited over the tubular body. The ends of the winding are bent to extend axially through preformed openings in the flange and beyond to constitute the leads or terminals for the coil. The difficulty with this construction is that the flange must be formed with the preformed openings to receive the coil leads, and thus, for every pin circle size or for every angular spacing of the pins within the pin circle, a different form, and, therefore, a different mold, must be provided, and molds are notoriously expensive.

SUMMARY OF THE INVENTION The present invention contemplates a tubular form without any such flange as is shown in the Renskers or Sutton patents. A collar or sleeve of any desired thickness may be slidably inserted over one end of a relatively simple tubular form and the integral leads of the winding stapled to and through the collar to the enclosed portion of the form. Thus, the collar serves to locate and reinforce the terminals and define the pin circle.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation of a transformer construction embodying the present invention;

FIG. 2 is a side elevation of the parts thereof in exploded relation; I

FIG. 3 is an enlarged section through the lower portion of FIG. 1 taken along the line 33 of FIG. 1 looking in the direction of the arrows;

FIG. 4 is a section along the line 44 of FIG. 1;

FIG. 5 is an enlarged diagrammatic fragmentary view of one of the leads of FIG. 4 and associated parts showing one mode of staple formation;

FIG. 6 is a view similar to FIG. 5 showing an optional mode of staple formation; and

FIG. 7 is a view similar to FIG. 3 showing an optional form of stapled coil construction.

DESCRIPTION OF A PREFERRED EMBODIMENT In FIG. 2 is shown a simple tubular plastic coil form 10 of nylon or the like which is entirely conventional in cross section. Adjacent, but spaced from its bottom end 12, an annular protruding rib 14 is molded thereinto.

The device also includes a simple paper or plastic collar 16 having an interior diameter adapted to fit snugly over the lower end 12 of the coil form 10 in telescoping relationshp and abut against the rib'l4. The length of the collar should be equal to or greater than the lower end portion 18 of the coil form and will be of various optional thicknesses. Since the collar deter- 2 mines the diameter of the pin circle, the thickness'will be determined by the pin circle size desired.

Inner and

outer windings

20 and 22 are likewise shown of the same general character as that shown in the above-referred-to patent to Renskers of relatively rigid wire, the end portions 24 of which are bent to extend axially with respect to the coil form below the bottom of the coil form and the free edge of the collar 16 when the coils are assembled to the form. The leads 24 of the inside coil 22 are carried out substantially from the helical body thereof so as to accommodate the outside winding in the space between.

Finally, the assembly includes wire staples 26 which are narrow to embrace the diameter of the wire terminals 24 closely.

The assembly of the device will be readily appreciated from the foregoing. The collar 16 will be seated on the lower end 18 of the coil form 10 and the prewound coils dropped on the portion of the coil form above the annular rib 14 with the leads thereof overlapping the collar 16. In such position the leads extend well beyond the collar. A staple will then be driven embracing each lead through the collar 16 and the wall of the lower end 18 and clinched against the inside tubular surface of the coil form. 1

FIGS. 5 and 6 illustrate alternative ways of clinching the staple. A driving element 28 of an ordinary stapling head will drive the staple 26 through the collar and form and against a cylindrical anvil 30 fitting within the form. The anvil may be smoothly cylindrical-as illustrated in FIG. 6 in which case the ends of the wires will be splayed outwardly as at 32. The anvil also may have a concavity 34 opposing the driver 28 and the lines of entry of the staple legs 36 which will clinch the staple legs inwardly as shown in FIG. 4, for instance.

It will be appreciated from the foregoing that the coil construction described is both versatile as to pin circle size and pin angularity, and inexpensive. The construction has yet another advantage. Wall sections of coil forms may be very thin where a high level of coupling with a tuning slug may be desired. The stapled collar will provide substantial reinforcement for the form in the area most subject to stress.

It will further'be appreciated that the part of the form over which the collar fits may have a diameter different from that enclosed by the coil.

It will be further appreciated that this invention may be practised without the sleeve. The reinforcement value and the variable pin circle size is sacrificed, but

the capability of varying the angular relation of the leads is retained and the stapling technique provides a strong, inexpensive and positive way of assembling the coil to the coil form and fixing the angular relationship of the leads without the high tooling costs involved in a flanged coil form. FIG. 7 illustrates such a structure.

In that figure a coil form 40 is shown having an upper coil mounting portion 42 of less diameter and a lower lead mounting portion 44 of greater diameter belling out therefrom. Pin circle sizes have been generally standardized through the television industry, and the lower end or hell 44 will generally be formed to conform to one of these sizes.

The

windings

46, 48 will be emplaced on the form portion 42 above the bell 44 with the leads 50 thereof extending longitudinally adjacent and across the bell and are stapled 52 directly thereto. This same teaching would be applicable to a coil form of uniform diameter, should such be desired.

It will be further appreciated that although this invention has been described in terms of a transformer characterized by two windings, it applies equally to simple coils. Likewise, the winding or windings may be located on the coil form in positions other than directly against the bead, or a plurality of coils may be longitudinally spaced over the length of the form.

I claim:

1. A mounted coil comprising a tubular coil form, a coil consisting of a plurality of turns of relatively stiff heavy wire mounted on said form away from one end thereof, the ends of said coil being bent to extend axially beyond said end of said form to define the leads of said coil, and staples embracing said leads and extending into said end of said form to fix the angular relationship of said leads.

2. The combination of claim 1 wherein the end of said form to which said leads are stapled has a larger diameter than that portion of said form mounting said turns of said coil,

3. The combination of claim 1 including additionally a sleeve mounted telescopically over said coil form end inside'said leads and said staples extend through said sleeve and into said ends to hold said leads against the outer surface of said collar whereby said collar determines the pin circle size of said coil.

4. The combination of claim 3 wherein one of said means as between said form and said sleeve'possesses means to limit the telescoping of said sleeve to said form.

5. The combination of claim 4 wherein said form has a circumferential bead thereabout to engage the end of

Claims

2. The combination of claim 1 wherein the end of said form to which said leads are stapled has a larger diameter than that portion of said form mounting said turns of said coil.

3. The combination of claim 1 including additionally a sleeve mounted telescopically over said coil form end inside said leads and said staples extend through said sleeve and into said ends to hold said leads against the outer surface of said collar whereby said collar determines the pin circle size of said coil.

4. The combination of claim 3 wherein one of said means as between said form and said sleeve possesses means to limit the telescoping of said sleeve to said form.

5. The combination of claim 4 wherein said form has a circumferential bead thereabout to engage the end of said sleeve.