US3470520A

US3470520A - Resistor with strip terminals

Info

Publication number: US3470520A
Application number: US639566A
Authority: US
Inventors: Lionel E Weyenberg
Original assignee: Individual
Current assignee: Individual
Priority date: 1967-05-18
Filing date: 1967-05-18
Publication date: 1969-09-30
Anticipated expiration: 1986-09-30

Description

P 0, 1969 I L. E. WEYENBERG 3,470,520

RESISTOR WITH STRIP TERMINALS Filed May 18, 1967 I f/dtawzava United States Patent 3,470,520 RESISTOR WITH STRIP TERMINALS Lionel E. Weyenberg, N 35, W 23575 Capitol Drive, Pewaukee, Wis. 53072 Filed May 18, 1967, Ser. No. 639,566 Int. Cl. H01c 1/14, 3/00 US. Cl. 338-302 8 Claims ABSTRACT OF THE DISCLOSURE Electrical resistors are generally formed'of wire helically wound on an insulating core. Secured around the core and connected to each end of the Wire coil is a terminal strip, and electrical leads are attached to each terminal strip. The use of slip-on type connectors, which connect the leads to the terminals of the resistor, has increased substantially in recent years. The typical slip-on connector includes a shank that is clamped to the lead wire and a head extends outwardly from the shank. The head of the connector has a flat base, and a pair of curved side members extend outwardly from the base. The connector is adapted to be slipped on to the end of a fiat terminal, with the terminal being inserted between the base and the side members and held within the connector by the frictional engagement.

To provide the necessary terminals for use with slip-on type connectors, a pair of flat prongs are generally welded to the terminal strip after the strip itself has been welded or otherwise secured to the core. A terminal strip of this type has decided disadvantages'in that the strip is diflicult to assemble because it necessitates not only welding the ends of the strip together to clamp the strip to the core, but in addition, the two prongs must subsequently be welded to the strip to provide the terminals. As a further disadvantage of the conventional terminal strip, the current is required to pass through the weld. Furthermore, the wire coil is usually potted or encapsulated in glass or vitreous enamel, and during the firing operation at elevated temperatures to fuse the vitreous enamel, the welds joining the prongs to the terminal strip frequently crack or fracture.

The present invention is directed to an electrical resistance apparatus, such as a resistor or rheostat, in which the terminal prongs which are to be engaged with a slipon type of connector are formed integrally with the terminal strip. According to the invention, the central portion or body of the strip is bent to the contour of the core and intermediate areas of the strip at each end of the body portion are disposed flatwise and welded together to clamp the strip to the core. The ends of the strip project outwardly from the welded area and serve as terminals to be inserted within the slip-on connectors.

The terminal strip construction of the invention is less costly than the conventional type in that only a single part and a single weld are required.

As the terminal prongs are an integral part of the strip, fracture or cracking of the prongs is minimized.

As a further advantage the current will not pass di- "ice rectly through the weld but instead will pass through the strip to the wound coil.

Other objects and advantages will appear in the course of the following description.

The drawings illustrate the best mode presently contemplated of carrying out the invention.

In the drawings:

FIG. 1 is a perspective view of a typical electrical resistor incorporating the terminal strip construction of the invention;

1316. 2 is a transverse section through the resistor showin g the terminal strip construction;

' ,IG. 3 is an exploded plan view of the terminal strip and slip-on connector;

FIG. 4 is an end view of the slipon connector; and

FIG. 5 is a view similar to FIG. 2 showing a modified form of the terminal strip.

The drawings illustrate an electrical resistor 1 having an insulating core 2, and a metal wire 3 is wound over the outer surface of the core in a spiral or helical pattern. Connected to each end of the coil 3 is a terminal strip 4 and both the coil 3 and the terminal strip 4 can be coated or encapsulated with an electrically insulating material 5, such as vitreous enamel, resin or the like.

As best shown in FIG. 2, each terminal strip 4 is provided with a central, generally circular body section 6 which is formed to the contour of the core 2. Located on each end of the body portion'6 is an intermediate section 7, and the intermediate sections 7 are disposed flatwise and welded together to securely clamp the strip 4 around the core 2.

Extending laterally from each intermediate section 7 is a section 8, and each lateral section 8 terminates in an end or prong 9 which is disposed generally parallel to the intermediate section 7 but is offset laterally from the corresponding section 7. Each of the terminal ends or prongs 9 is adapted to be received within a slip-on type of connector 10.

As best illustrated in FIG. 3, the outer corners 11 of each prong 9 are beveled to facilitate insertion of the prong within the connector 10, and each prong 9 is provided with a pair of shoulders 12 which serve as stops and limit the inward movement of the connector 10 on the prong. Located centrally of each prong 9 is a hole 13 which aids in frictionally retaining the connector 10 on the prong 9,

as will be hereinafter described.

The slip-on connector 10.is a conventional type and includes a tubular shank 14 which is claimed around the lead wire 15. Extending outwardly from shank 14 is a head 16 which includes a flat base member 17 and a pair of generally curved lateral sections 18 which extend upwardly from the sides of the base 17. The shank 14 is coated with a suitable electrical insulating material 19.

The flat prong 9 of the terminal strip 4 is adapted to be inserted within the space between the base 17 and the lateral sections 18. To prevent the connector from slipping from the terminal prongs 9, the base 17 is provided with a pair of transverse slots 20 and a central dimple 21 The slots 20 and dimple 21 act to frictionally engage the edges of prong 9 bordering the hole 13 to thereby prevent the connector from freely slipping from the prong.

To fabricate the resistor of the invention, one of the terminal strips 4 is initially applied to the ceramic core 2 and the sections 7 welded to clamp the strip to the core. One end of the resistance wire is then welded to the strip 4 and is wound around the core. Following the winding of the coil, the second terminal strip is applied to the core and the sections 7 of the strip are welded together. The wire coil is then welded to the second terminal strip 4. After the welds have been completed, the coil 3 can be coated or potted with a suitable insulating coating such as vitreous enamel, resin, or the like, and fired, if necessary, to fuse or cure the coating.

FIG. 5 illustrates a modified form of the invention which includes a terminal strip 22, similar to strip 4 of the first embodiment. Strip 22 includes a generally circular body portion 23 which is formed to the contour of the ceramic core 2. Located at each end of the body portion 23 are intermediate sections 24 which are welded flatwise together to firmly secure the strip to the core. Extending outwardly from each intermediate area 24 is a terminal prong 25 which is adapted to receive the slip-on connector 10. The prongs 25 extendat an acute angle to the respective intermediate sections 24 and diverge outwardly.

The terminal strip construction of the invention is relatively inexpensive in that a single part is required and only a single weld is necessary to attach the strip to the core. As only a single weld is required, this substantially reduces the labor cost in fabricating the resistor.

As a further advantage, the terminal strip is substantially more secure than conventional types because the terminal prongs are an integral part of the strip and are therefore less likely to crack or break away during service.

Moreover, the current is not required to pass through the weld with the present terminal strip construction, but instead passes directly through the strip 4 between the connector 10 and the coil 3.

While the drawings illustrate the terminal strip construction as applied to a resistor, it is contemplated that the same construction can also be utilized with rheostats and other electrical apparatus.

Various modes of carrying out the invention are contemplated as being within the scope of the following claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention.

I claim:

1. An electrical apparatus, comprising an electrically insulating core, an electrical conductor disposed around the core, a one-piece terminal strip connected to the conductor and including a central body portion disposed around the core, said terminal strip also including a pair of intermediate sections disposed at the ends of the body section and disposed generally flatwise to each other, said terminal strip also including a pair of end sections formed integrally with the respective intermediate sections and extending outwardly therefrom, said end, sections being spaced apart and disposed to receive slip-on electrical connectors, and connecting means for connecting the intermediate sections together to clamp the strip around said core.

2. The electrical apparatus of claim 1, in which the conductor is a wire coil wound around the core.

3. The apparatus of claim 2, in which the core is gen- 4 erally cylindrical in shape and the body portion of the terminal strip is generally circular in cross section.

4. The apparatus of claim 1 in which said connecting means comprises a weld.

5. The apparatus of claim 1, in which the end sections are generally fiat and are adapted to be received within a recess in said connectors, and stop means associated with said end sections to limit the reception of said end sections with said connectors.

6. The apparatus of claim 1, in which said end sections are disposed generally parallel to each other and each end section is located in generally parallel offset relation to the respective intermediate section.

7. The apparatus of claim 1, in which each end section is disposed at an acute angle to the respective intermediate section and said end sections diverge outwardly from each other.

\ 8. An electrical apparatus, comprising an electrically I insulating core, a resistance wire wound around the core,

a one-piece terminal strip connected to said wire and including, a central body portion disposed aroundthe core, said terminal strip including a pair of intermediate sections disposed at the ends of the body section and disposed generally flatwise to each other, said terminal strip clamp the strip around the core, and frictional means for preventing free removal of the end sections from said connectors.

References Cited UNITED STATES PATENTS 995,435 6/ 1911 Bolling 338-308 1,748,536 2/ 1930 Borden 338-251 I 2,709,211 5/1955 Glynn 338-322 X 2,787,693 4/1957 Razlag 338-322 X 3,358,260 12/1967 Schaecher 338-302 FOREIGN PATENTS 440,812 l/ 1936 Great Britain. 462,499 3/ 1951 Italy.

EQA. GOLDBERG, Primary Examiner US. Cl. X.R.