US3800263A

US3800263A - Combination terminal and fuse holder arrangement for an electrical circuit

Info

Publication number: US3800263A
Application number: US00249791A
Authority: US
Inventors: G Ammerman; W Mcfarlane
Original assignee: Heatcraft Inc
Current assignee: Heatcraft Inc
Priority date: 1972-05-03
Filing date: 1972-05-03
Publication date: 1974-03-26
Anticipated expiration: 1991-03-26
Also published as: FR2182847B3; FR2182847A1; IT979069B; JPS4922542A; DE2312433A1

Abstract

A combined terminal and fuse holder arrangement utilized in an electrical circuit, such as an open coil heater assembly. The terminal includes an insulator which supports a projecting arm having an aperture to receive a screw. The end of a circuit element is formed in a loop to hook about the body of the screw, the screw holding the element in electrical connection with the arm. The arm is bridged electrically through a fuse to a terminal contact which is also supported by the insulator.

Description

United States Patent 119 Ammerman et a1.

COMBINATION TERMINAL AND FUSE HOLDER ARRANGEMENT FOR AN ELECTRICAL CIRCUIT Inventors: George Edward Ammerman;

' William McFarlane, both of Murfreesboro, Tenn Assignee: Heatcraft, Inc., Murfreesboro,

Tenn.

Filed: May 3, 1972 Appl. No.: 249,791

US. Cl 337/237, 219/517, 337/231, 1 337/235, 337/253 Int. Cl. HOlh 85/16 Field of Search 219/517, 532, 523, 253, 219/541, 536; 337/202, 203, 231, 237, 235, 253, 9, 181

References Cited UNITED STATES PATENTS l/l949 Harlow 337/9 1451 Mar. 26, 1974 2,211,520 8/1940 Smith .Q. 219/517 x FOREIGN PATENTS OR APPLICATIONS 743,205 1/1933 France 337/181 Primary Examiner-Bernard A. Gilheany Assistant Examiner-Fred E. Bell Attorney, Agent, or FirmCushman, Darby & Cushman 5 7] ABSTRACT A combined terminal and fuse holder arrangement utilized in an electrical circuit, such as an open coil heater assembly. The terminal includes an insulator which supports a projecting arm having an aperture to receive a screw. The end of a circuit element is formed in a loop to hook about the body of the screw, the screw holding the element in electrical connection with the arm. The arm is bridged electrically through a fuse to a terminal contact which is also supported by the insulator.

4 Claims, 4 Drawing Figures The invention generally relates to an improved construction for servicing a fused electrical circuit, such as an open coil heater assembly. In such assemblies, fuses frequently require replacement. Conventionally, the fuse is connected in the circuit such that the entire heater assembly must be removed from its operative position and the fuse replaced by breaking one or more mechanical connections, removing the defective fuse, attaching the new fuse in place, and relocating the entire assembly in its operative position. Such steps are inconvenient and costly.

In an effort to avoid entire assembly removal, heater assemblies have been developed which utilize separate terminals for supporting the fuse and the heater coil. Besides being uneconomical, such arrangements suffer the further shortcoming of occupying considerable space on the base plate of the assembly and requiring a jumper from one terminal to the other. These factors are of substantial importance in multicoil assemblies which usually include control elements, such as relays and temperature responsive devices, the proper positioning of which is complicated by the presence of a considerable number of terminals. I

Briefly, the invention relates to the latter type of system wherein the entire assembly need not be removed but wherein the number of terminals is reduced and replacement of defective parts is facilitated by combining the fuse supporting and coil end holding functions in a single terminal. The terminal includes an insulator for supporting an arm which projects towards the heating coil. The arm has an aperture for receiving a screw, and the end of the heating coil loops about the screw and is electrically connected to the arm when the screw is tightened. A fuse electrically bridges the arm to a terminal contact which also is supported by the insulator.

The invention will be described in further detail by reference to the accompanying drawings, wherein:

FIG. 1 illustrates a conventional prior art arrangement for connecting a fuse and a coil in an open coil heating assembly, the arrangement being of the type in which the entire heating assembly need not be removed from its operative position in order to replace the fuse;

FIG. 2 is an elevational view of an open coil heating element assembly incorporating the present invention;

FIG. 3 is an elevational view of the assembly taken at 90 to that view shown in FIG. 2; and

FIG. 4 is a view in section of the insulator portion of the terminal taken along line 4-4 of FIG. 3.

Referring to FIG. I, there is disclosed a known mannor of securing a fuse and a heater coil end in an open coil heater assembly. A plate serves as a base for supporting a pair of terminals having insulators I2 and l4. Insulator 12 is a two-piece construction held together by a screw 16 passing along the axes of the pieces and cooperating with a pair of nuts 18. The heater coil 20 is soldered to the head of screw 16. Insulator 14 is connected to the base plate by means of a screw 22 passing through an ear 24 projecting from the insulator. A pair of

contacts

26 and 28 are provided at one end of insulator l4, and

arms

30 and 32 project from the opposite end. Contact 26 and arm 30 are in electrical connection as are contact 28 and arm 32. A fuse 34

bridges arms

30 and 32, and the fuse is electrically joined to coil 20 by a jumper 36 joined between contact 28 and the screw 16. The nuts 18 secure the 5 jumper in electrical contact with the screw.

With the arrangement just described, it is often the practice in replacing the fuse to discard the entire insulator-fuse assembly (14, 34) in favor of a new one. This constitutes an economical disadvantage for the FIG. 1 arrangement.

However, more important than the expense of replacing the several parts in the arrangement of FIG. 1 is the serious disadvantage of their taking up a substantial amount of space on the surface of base plate 10. The necessity of two terminals hinders the placement on the base plate of other important components of an open coil heater system such as relays, temperature responsive devices, etc. The problem increases as the number of heater coils becomes greater.

The shortcomings of prior art systems are overcome by the present invention as disclosed in FIGS. 24. Referring to FIGS. 2 and 3, there is illustrated the base plate 10 and support structure, generally indicated as 40, for the open coil heater 20. The support structu e, which is fully described in US. Pat. No. 3,641,312 granted on Feb. 8, 1972, forms no part of the present invention.

A single terminal is used to support a fuse 34 and the end of heater coil 20. The terminal includes an insulator which is preferably ceramic formed with an exterior shoulder 44 (FIG. 4) which abuts the base plate 10 when the insulator is properly positioned to project through an aperture in the base plate. The insulator includes an car 46 through which a screw 48 extends to secure the insulator 42 to the base plate.

The interior of the insulator 42 is provided with passages (FIG. 4) to receive electrically conductive elements. One of these elements is an arm 50 which has a U-shaped cross-section; Arm 50 abuts an internal shoulder 52 formed within a first passage 54, and coextensive with arm 50 is a projection 56 having ears 58 which are bent to engage the outer surface of insulator 42 thereby maintaining arm 50 in fixed position with respect to the insulator. Similarly, a shorter arm 60 abuts shoulder 62 formed within a second passage 64. Coextensive with arm 60 is a projection 66 which extends beyond the insulator 42 to serve as a contact 68. Again, arm 60 is held in fixed position by ears 70 which engage the outer surface of insulator 42.

A fuse 34 has its ends attached to

arms

50 and 60. The flat surface of the U-shaped arm 50 is provided with an aperture to receive a screw 72. The end of coil 20 is bent in a loop 74 to be hooked about the body of screw 72 so that when the screw is tightened, an electrical circuit is assured from contact 68, through projection 66, arm 60, fuse 34 and arm 50 to the heater coil 20.

Preferably the end of loop 74 of the heater coil is arranged to extend beyond the end of arm 50. Thus, when a fuse is found defective, the screw 48 is undone to permit the insulator 42 to be disconnected from base plate 10. The insulator is then withdrawn from the base plate against the spring tension of coil 20. At a point when the loop 74 projects through the aperture in base plate 10, the loop end is hooked on the surface of the base plate. The screw 72 is then disconnected to separate the coil 20 from the insulator assembly. A new assembly can then be substituted and the coil attached thereto by means of screw 72. When the loop end of coil is unhooked from the base plate, the spring tension snaps the insulator into place against the base plate, where it is firmly affixed by screw 48.

From the foregoing it can be appreciated that the invention resides in a structural arrangement for a combination fuse holder and terminal for an electrical circuit employing a single element which is attached to a base plate. The arrangement disclosed permits ease of replacement of components and occupies much less space than conventional replaceable fuse holder arrangements. While the embodiment shown is that used for a single coil, it should be appreciated that the insulator 42, which comprises a principal part of the terminal, may be formed with additional passages so as to permit termination of plural circuits in a manner such as that just described for a single circuit.

What is claimed is:

l. A combined terminal and fuse holder adapted to project through an aperture of a supporting plate associated with an electrical circuit arrangement, such as an open coil heater assembly, comprising:

I an insulator element havinga pair of passages extending therethrough;

a first arm positioned within one of said passages and having an electrical contact extending beyond one side of the insulator element;

a second arm positioned within the other of said passages and projecting beyond the opposite side of the element;

a fuse connected between the projecting portion of said second arm and said first arm to complete an electrical path from the contact through said first passage and the fuse to said projecting portion of the second arm;

means for securing said arms within their respective passages, said securing means for at least the second arm including fastening means integral with said arm and engaging a surface of the insulator element to hold said arm in fixed position within its passage with a portion of the arm abutting a shoulder defined by the passage internally of said element; and

means on the projecting portion of the second arm for removably securing an end of said electrical circuit to said arm whereby the terminal and fuse holder are separated from the circuit arrangement when the end of said circuit is disconnected from said second arm.

2. A combined terminal and fuse holder as set forth in claim 1, wherein said fastening means includes cars bent to engage said insulator element surface.

3. In an electrical circuit assembly, a combined terminal and holder for a thermal fuse adapted to project through an aperture of a supporting plate associated with said electrical circuit to removably locate said fuse adjacent to and in thermally operative relationship with a second arm joined to said insulator element and projecting beyond the opposite side of the element whereby said second arm is accessible from the opposite side of the plate;

said thermal fuse being positioned on the opposite side of the element and connected between the projecting portion of the second arm and said first arm; and

4. In an electrical circuit assembly as set forth in claim 3, the combined terminal and fuse holder further comprising:

an additional passage extending through said insulator element and defining a shoulder internal of said element, the second arm being positioned within said additional passage; and

fastening means integral with said second arm and engaging a surface of the insulator element to join said arm to the element by holding said arm in fixed position within its associated passage with a portion of the arm abutting the internal shoulder.

Claims

1. A combined terminal and fuse holder adapted to project through an aperture of a supporting plate associated with an electrical circuit arrangement, such as an open coil heater assembly, comprising: an insulator element having a pair of passages extending therethrough; a first arm positioned within one of said passages and having an electrical contact extending beyond one side of the insulator element; a second arm positioned within the other of said passages and projecting beyond the opposite side of the element; a fuse connected between the projecting portion of said second arm and said first arm to complete an electrical path from the contact through said first passage and the fuse to said projecting portion of the second arm; means for securing said arms within their respective passages, said securing means for at least the second arm including fastening means integral with said arm and engaging a surface of the insulator element to hold said arm in fixed position within its passage with a portion of the arm abutting a shoulder defined by the passage internally of said element; and means on the projecting portion of the second arm for removably securing an end of said electrical circuit to said arm whereby the terminal and fuse holder are separated from the circuit arrangement when the end of said circuit is disconnected from said second arm.

2. A combined terminal and fuse holder as set forth in claim 1, wherein said fastening means includes ears bent to engage said insulator element surface.

3. In an electrical circuit assembly, a combined terminal and holder for a thermal fuse adapted to project through an aperture of a supporting plate associated with said electrical circuit to removably locate said fuse adjacent to and in thermally operative relationship with said circuit, the combined terminal and fuse holder comprising: an insulator element adapted to be removably secured to said plate and to project through said aperture, said insulator having a passage extending therethrough; a first arm positioned within said passage, said arm having an electrical contact extending beyond one side of the insulator element to permit access thereto from one side of the plate; a second arm joined to said insulator element and projecting beyond the opposite side of the element whereby said second arm is accessible from the opposite side of the plate; said thermal fuse being positioned on the opposite side of the element and connected between the projecting portion of the second arm and said first arm; and means on the projecting portion of the second arm for removably securing an end of said electrical circuit to said arm whereby the terminal and fuse holder are separated from the circuit arrangement when the end of said circuit is disconnected from said second arm.

4. In an electrical circuit assembly as set forth in claim 3, the combined terminal and fuse holder further comprising: an additional passage extending through said insulator element and defining a shoulder internal of said element, the second arm being positioned within said additional passage; and fastening means integral with said second arm and engaging a surface of the insulator element to join said arm to the element by holding said arm in fixed position within its associated passage with a portion of the arm abutting the internal shoulder.