US3688395A

US3688395A - Construction method of making electrical connection

Info

Publication number: US3688395A
Application number: US810451A
Authority: US
Inventors: Harold K Cummings
Original assignee: Bunker Ramo Corp
Current assignee: Bunker Ramo Corp
Priority date: 1969-03-26
Filing date: 1969-03-26
Publication date: 1972-09-05
Anticipated expiration: 1989-09-05
Also published as: GB1287335A; DE2014829A1; FR2035905A1

Abstract

A construction and method of making an electrical connection in which a base member having a metal outer surface is provided with cutting serrations for cutting through the immediately adjacent insulation of an insulated wire wound thereon to provide electrical contact therebetween. To increase the reliability of electrical contact, the insulated wire is wound at an initial position on the base member and then slidably moved across the cutting serrations to a final position.

Description

Unite States Patent Cummings 1 Sept. 5, 1972 [54] CONSTRUCTION METHOD OF 3,288,915 11/1966 Hatfield et al. ..339/276 MAKING ELECTRICAL CONNECTION 2,870,241 1/1959 Mason ..339/276 2,759,166 8/1956 Mallina ..29/505 [72] Inventor a? cumm'ngs 3,130,355 4/1964 Younger ..336/192 [73] Assignee: The Bunker-Ramo Corporation, Prim ry xa iner-John F. Campbell Oak Brook, Ill Assistant ExaminerD. M. Heist At -Fd 'kM.Ab kl 22 Filed: March 26,1969 omey re em r e [21] Appl. No.: 810,451 ABSTRACT A construction and method of making an electrical 52 US. (:1. ..29/605, 29/628, 29/606 Connection in which a base member having a metal 51 Int. Cl .1101: 7/05 Outer Surface is Provided with Cutting serrafims for 5 Field f Search 29/ 05 0 2 30 A 432. cutting through the immediately adjacent insulation Of 276 336/192 an insulated wire wound thereon to provide electrical contact therebetween. To increase the reliability of electrical contact, the insulated wire is wound at an in- [56] References Clted itial position on the base member and then slidably UNITED STATES PATENTS moved across the cutting serrations to a final position.

3,445,797 5/1969 Otto ..336/l92 4 Claims, 5 Drawing Figures ill ll lliil! ll ll CONSTRUCTION METHOD OF MAKING ELECTRICAL CONNECTION BACKGROUND OF THE INVENTION This invention relates generally to means and methods for providing an electrical connection between a base member and an insulated wire.

A typical electrical connection situation to which the present invention may advantageously be directed involves the provision of electrical connections to the relatively delicate ends of the wire forming an electrical coil. Such connections can involve a significant expense in the manufacture of electrical and electromechanical devices. For example, an automobile clock typically employs an electromagnetic motor having a solenoid-type multi-layer coil formed of an insulatively coated wire wound on a suitable spool, and through the center of which a cylindrical iron or steel core is provided. A spring-loaded magnetizable armature is disposed so as to oscillate in response to appropriate signals applied to the coil, the oscillating armature being used to provide the driving energy for a clock mechanism. Such a coil ordinarily requires at least two electrical connections to be made thereto, which is conventionally accomplished manually by first stripping the insulation off the relatively delicate ends of the coil, and then soldering or welding or gunwrapping the exposed ends to respective terminals. It will be recognized that significant expense is involved in providing the electrical connections to the coil in this manner, which could amount to a very considerable dollar expense where thousands of these clocks are being manufactured.

Another electrical connection situation to which the invention may advantageously be directed involves the making of an electrical connection between a terminal and an insulated wire provided thereon, such as by gunwrapping.

SUMMARY OF THE INVENTION The present invention provides a novel construction and method for making any electrical connection between a base member and an insulated wire, such as for the purposes exemplified above. In an exemplary embodiment involving a multi-layer solenoid-type coil of an electromagnetic clock driving motor of the type previously mentioned, the cylindrical steel or iron core to be used with the coil is provided with cutting means at appropriate locations on its periphery. The coil is formed of an insulatively coated wire wound directly on the core, such as by using an automatic coil winder. The tension on the wire during winding is such that the cutting means provided on the periphery of the core cuts through the insulation of the wire so as to thereby provide an electrical connection between the core and the adjacent coil wire wound thereon. In order to provide further assurance that a good electrical connection is made, the coil is initially wound a short distance to the side of its permanent location and then slid longitudinally to the permanent location, whereby a sliding cutting action occurs between the coil and the cutting means of the core to insure that the desired electrical connection therebetween is achieved. Having made electrical contact between the core and the inner end of the coil, the metal supporting means to which the core is normally aflixed may, thus, be used to conveniently provide one of the required electrical connections to the coil, thereby eliminating the need for one of the conventionally required soldered or welded electrical connections to the coil. An electrical connection can be provided between a terminal and an insulated wire wrapped thereon in a similar manner to that described for the coil and core.

It is a broad object of the invention to provide improved means and methods for making an electrical connection between a base member and an insulated wire.

A more specific object of the invention is to provide a coil construction and method for making which permits one of the required electrical connections to the coil to be obtained in a simple and convenient manner without requiring soldering or welding to the wire forming the coil.

It is a further object of the invention to provide means and methods for providing electrical connection between a terminal and a wire wrapped thereon.

The specific nature of the invention as well as other objects, uses, features and advantages thereof will become apparent from the following description of an exemplary embodiment taken in conjunction with the accompanying drawing in which:

FIG. 1 is a perspective view of a base member, coil form, or core having cutting serrations in accordance with the invention;

FIG. 2 is a cross-sectional view taken along the line 2-2 in FIG. 1;

FIG. 3 is a side view of the core of FIGS. 1 and 2 with a coil wound thereon at a temporary initial position;

FIG. 4 is a side view similar to FIG. 3 with the coil moved to its final position on the core; and

FIG. 5 is a view of an exemplary motor assembly employing the coil and core of FIG. 4.

Like numerals refer to like elements throughout the figures of the drawing.

Referring to FIGS. 1 and 2, illustrated therein is a cylindrical metal base member, coil form or core 10 having conductive cutting serrations 10a provided on the periphery thereof. For the purposes of the exemplary embodiment being described herein, the base member 10 will be considered to be a steel or iron core, such as used in the coil of an automobile clock. As shown, the core 10 has a shoulder 1012 provided at one end thereof.

As illustrated in FIG. 3, a multi-layer solenoid-type winding or coil 15 is wound on the core 10. The coil 15 is formed of wire having an insulative coating and is wound on the core 10 using any suitable means, such as an automatic coil winder. The inner end of the coil is indicated by 150, and the outer end of the coil 15 is indicated by 15b. The tension provided on the wire during winding is chosen to be such that the cutting serrations 10a provided on the periphery of the core 10 cut through the insulation of the adjacent coil wire wound thereagainst so as to thereby make electrical contact between the core 10 and a portion of the coil wire near the inner end 15a of the coil 15.

In the exemplary embodiment of the invention being considered herein, the position of the coil 15 on the core 10 shown in FIG. 3 is only a temporary initial position. After the coil 15 is wound at this initial position, it is then slid by any suitable means in the direction indicated by the arrow A in FIG. 3 to its final position against the shoulder 10b as shown in FIG. 4. This sliding movement enhances the cutting action between the cutting serrations 10a of the core 10 and the adjacent coil wire wound thereagainst so as to further insure that a good electrical contact is achieved therebetween. It will be understood that when this longitudinal sliding movement is provided, as in the exemplary embodiment being considered herein, it is not necessary that the winding of the coil 15 on the core 10 in the initial position shown in FIG. 3 actually cause piercing of the insulation of the coil wire, as long as sufficient piercing occurs during the sliding of the coil 15 to its final position to permit reliable electrical contact to be achieved. The provision for this sliding movement of the coil 15 from its initial to its final position on the core 10, thus, relieves the requirements on the cutting serrations and the wire tension during winding of the coil, since cutting through the wire insulation to make electrical contact need not be accomplished at that time. It is additionally to be noted with regard to FIG. 4 that the inner end 15a of the coil 15 has been cut off, since the electrical connection to the core 15 provided as described above obviates the need for direct connection to the inner end 15a of the coil. This will become more evident from the next following description of FIG. 5.

With reference to FIG. 5, illustrated therein is a clock motor assembly incorporating the coil 15 and core 10 assembly of FIG. 4. The clock motor assembly of FIG. may typically be used, for example, to provide the driving energy for an automobile clock mechanism (not shown). Obviously, such an illustrated use for the invention is only exemplary, since the invention is subject to use in a wide variety of different applications.

It will be understood from FIG. 5 that the coil 15 and core of FIG. 4 may be secured in a metal bracket 24 by a tight push fit provided between the end 100 of the core 10 and a bore 24a provided in a depending portion 24b at one end of the bracket 24. The bracket 24 is secured to an insulative plate 30, such as one made of plastic, by any suitable means (not shown). In order to provide for application of the required input signals to the coil 15, the outer end b thereof is stripped and soldered in the usual manner to an input terminal 31 suitably secured to the insulative plate 30. However, it is not necessary to directly connect to the inner end 150 of the coil 15, since the assembly of FIG. 4 will already provide electrical contact between the core 10 and the inner end 15a. Accordingly, it is merely necessary, as illustrated in FIG. 5, to provide a suitable input terminal 33 depending from the metal bracket 24. Obviously, the connection to the inner end 15a of the coil 15 could also be accomplished by providing a terminal on any other metal member which is connected to the core 10, either directly or via one or more intervening metal parts.

Continuing with the description of the exemplary embodiment of the clock motor assembly illustrated in FIG. 5, a magnetizable armature 40 is pivotably coupled to the upper side of the bracket 24 (as viewed in FIG. 5) in a conventional manner and spring-biased by a spring 42 coupled therebetween so that the armature 40 oscillates between the illustrated positions in response to appropriate signals applied to the coil 15 via

terminals

31 and 33. The armature 40 is coupled to a clock mechanism (not shown) for providing the driving energy therefor in a conventional manner. l-Ioles 300 are provided in the insulative plate 30 to permit proper aligning of the armature 40 with the clock mechanism when the two are assembled.

Although the invention has been described in connection with a particular exemplary embodiment, it is to be understood that many modifications and variations in construction, arrangement and/or use are possible without departing from the spirit of the invention. For example, it will be recognized from the description herein that the core 10 need not be cylindrical but may have any other desired shape suitable to permit cutting serrations to be provided thereon for cutting into the wire of a coil wound thereon in accordance with the invention.

The invention could also be implemented with a nonmetallic coil form having conductive cutting serrations provided on the periphery of the coil form during winding of the coil along with appropriate conductive means electrically coupled to the serrations to provide for a convenient electrical connection.

Also, as pointed out previously herein, the invention may be advantageously utilized for providing an electrical connection between a terminal and an insulated wire wrapped thereon, such as by gun-wrapping. In such a case, the base member 10 would be a terminal and the winding 15 would be an insulated wire wrapped thereon.

The above examples of possible modifications are merely exemplary of many that could be provided. The present invention, therefore, should be considered as including all possible versions of the invention coming within the scope of the appended claims.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In a method of making an electrical connection,

providing a base member having conductive cutting means on the surface thereof, winding a coil of insulated wire at an initial position on said base member spaced from said cutting means and sufficiently loosely thereon to permit the sliding of said coil relative to said base, and

moving the insulated wire coil wound on the base member to a final position in a manner so as to cause the cutting means to shear the insulation of the insulated wire and make electrical contact therewith.

2. The invention in accordance with claim 1,

wherein said base member has an outer conductive surface on which said cutting means is formed, and wherein said insulated wire is wound to form a coil of the multi-layer type.

3. The invention in accordance with claim 1,

wherein said base member is a terminal to which said insulated wire is to be electrically connected.

4. A method of making a multi-layer electrical coil of insulated wire, the steps of:

providing a generally longitudinal core on which said multi-layer electrical coil is to be wound, said core containing at least one conductive longitudinally extending cutting serration formed on the periphery of said core and serving as one terminal for said coil,

winding said multi-layer coil of insulated wire on said coil over said cutting serration to a final position so core at an initial position longitudinally spaced that the cutting serration cuts the insulation of the from said cutting serration and sufficiently loosely Portion the insulated wire which moves thereon to permit the sliding of said coil longituthereagams} so as to thereby make electrical dinally on said core, and 5 tact therewithlongitudinally moving the thus wound multi-layer

Claims

1. In a method of making an electrical connection, providing a base member having conductive cutting means on the surface thereof, winding a coil of insulated wire at an initial position on said base member spaced from said cutting means and sufficiently loosely thereon to permit the sliding of said coil relative to said base, and moving the insulated wire coil wound on the base member to a final position in a manner so as to cause the cutting means to shear the insulation of the insulated wire and make electrical contact therewith.

2. The invention in accordance with claim 1, wherein said base member has an outer conductive surface on which said cutting means is formed, and wherein said insulated wire is wound to form a coil of the multi-layer type.

3. The invention in accordance with claim 1, wherein said base member is a terminal to which said insulated wire is to be electrically connected.

4. A method of making a multi-layer electrical coil of insulated wire, the steps of: providing a generally longitudinal core on which said multi-layer electrical coil is to be wound, said core containing at least one conductive longitudinally extending cutting serration formed on the periphery of said core and serving as one terminal for said coil, winding said multi-layer coil of insulated wire on said core at an initial position longitudinally spaced from said cutting serration and sufficiently loosely thereon to permit the sliding of said coil longitudinally on said core, and longitudinally moving the thus wound multi-layer coil over said cutting serration to a final position so that the cutting serration cuts the insulation of the portion of the insulated wire which moves thereagainst so as to thereby make electrical contact therewith.