US3261948A

US3261948A - Multiposition fuse carrier

Info

Publication number: US3261948A
Application number: US336948A
Authority: US
Inventors: Herman H Kobryner; Alexander R Norden
Original assignee: Murray Manufacturing Corp
Current assignee: Cooper Industries LLC; Murray Manufacturing Corp
Priority date: 1964-01-10
Filing date: 1964-01-10
Publication date: 1966-07-19
Anticipated expiration: 1983-07-19

Description

2 Sheets-Sheet 1 IN VEN TOR.

mm M x y w July 19, 1966 H. H. KOBRYNER ETAL MULTIPOSITION FUSE CARRIER Filed Jan. 10, 1964 PANEL BOARD 5A8:

United States Patent 3,261,948 MULTIPOSITION FUSE CARRIER Herman H. Kohryner, Forest Hills, and Alexander R.

Norden, New York, N.Y., assiguors to Murray Manufacturing Corporation, Brooklyn, N.Y., a corporation of New York Filed Jan. 10, 1964, Ser. No. 336,948 10 Claims. (Cl. 200-114) This invention relates generally to niulti-position threaded fuse carriers and more particularly to improved line contact elements and load contact elements for multiposition threaded fuse carriers.

Fuse carriers are generally rectangular structures which are adapted to receive fuses and to be mounted in a panel board to connect the fuses to a bus bar or line conductor within the paned board. In the case of multiposition threaded fuse carriers, a plurality of recesses are provided in the fuse carrier, and each recess is fitted with a threaded shell and a line contact element at the bottom of the recess to make cont-act with the button or line contact on the bottom of a threaded fuse when it is screwed into the threaded shell. Each of the line contact elements are connected by means of conductors to a connector which is adapted to make contact with a bus bar or line conductor within the panel board. In addition, each of the threaded shells is connected to a load contact element which is insulted from the line contact element (in prior devices the load contact element underlays the line contact element, with fibrous insulation being present between the two). Each load contact element is connected to'a corresponding load connector which is mounted on the fuse carrier to receive a conductor from the load circuit to be controlled by the corresponding fuse. When the mul-ti position fuse carrier is mounted in a panel board, and connected to the appropriate line and load circuits, current flows from the bus bar to the line contact of each fuse, then through the fuse element to the corresponding load contact, and from the load contact to the corresponding load circuit.

This invention is directed to improvements in threaded fuse carriers of the above described type, and more particularly to improvements in the line contact and load contact portions of the structure. In accordance with one aspect of this invention, there is provided a novel unitary line contact structure which is capable of simultaneously connecting a plurality of fuse line contacts to a bus bar. Furthermore, this unitary line contact structure is adapted to automatically make Wiping contact with an upstanding bus bar when the fuse carrier is plugged into a panel board. In accordance with another aspect of this invention, there is provided a novel unitary load contact structure which is capable of being connected to its corresponding fuse shell without connectors or insulators, laterally offset relative the axis of the fuse shell. In accordance with a further aspect of this invention, there is provided a multi-position threaded fuse carrier which is simple, reliable, inexpensive, easy to assemble, easy to install, and capable of being made by mass production techniques. Other improvements provided by this invention will become apparent to those skilled in the art from the following description of one specific embodiment thereof, as illustrated in the attached drawing, in which:

FIG. 1 is a plan view of a portion of one fuse carrier of this invention;

FIG. 2 is an elevation section of the embodiment shown in FIG. 1;

'FIG. 3 is a bottom view of the embodiment shown in FIG. 1;

FIG. 4 is a perspective view of a first line contact structure of this invention;

FIG. 5 is a perspective view of a second line contact structure of this invention;

Y line contact buttons.

FIG. 6 is a perspective view of a first load contact structure of this invention;

FIG. 7 is a perspective view of a second load contact structure of this invention.

FIG. 8 is a side, partial sectional view of the carrier and sections of the bus bars; and

FIG. 9 is a bottom View of the carrier shown in FIG. 8.

Referring to FIGS. 1, 2, 3, 8 and 9, one illustrative fuse carrier of this invention comprises a carrier body member 10 containing at least two, and preferably four, fuse sockets which comprise recesses 12 and 14 (F161), and 13, 15 (FIG. 8), and corresponding threaded

fuse shells

16 and 17, 18 and .19. Body member 10 is made of a suitable insulating material, and the threaded fuse shells 16 through 19 are made of a suitable conducting material. For simplicty, we shall hereinafter refer to half the carirer as shown in FIGS. 1-3.

Fuse shells

16 and 18 areheld in their respective recesses by means of the novel load contact structure of this invention, as will be explained in detail in later paragraphs. At the bottom of the recesses are

line contact elements

20 and 22, repectively, which form part of an integral line contact structure which also includes a bus bar contact 24 which is adapted to make wiping contact with an upright bus bar 26 (both bus bars are shown in FIG. 8). Bus bar 26 is conventionally secured by a connector, and other means not shown, to a panel board body member 28. A sliding lock bar 30 having openings formed therein to receive toes 32 cooperates with lugs 31 on the opposite side of the fuse carrier 10 as shown in FIG. 8. Bus bar contact 24 automatically makes wiping contact with bus bar 26 when the fuse carrier body member is properly located in the panel board 28.

The unitary line contact structure of this invention is approximately Y shaped, as better shown in FIGS. 4 and 5, which illustrate two different configurations of the basic shape. The upwardly projecting

arms

19 and 21 of the Y are shaped and dimensioned to extend into the base of their respective fuse sockets and in position to engage the button of the corresponding fuse on the

angled ends

20 and 22 which comprise the line contact elements. The depending portion 23 of the Y is shaped and located to make wiping contact with an upstanding bus bar at end 24. The difference between the configurations shown in FIGS. 4 and 5 relates to the position of the fuse sockets relative to the bus bars. In the preferred form of the novel fuse carrier (FIG. 8), the line contacts are asymmetrically located relative to the bus bar-s so that two

fuse shells

17, 19 are on opposite sides of one bus bar, and the other two

fuse shells

16, 18 are to one side of the other bus bar.

The line contact structure is attached to the bottom of the fuse carrier 10 by means of a screw 29 fitting in a tapped hole formed in the fuse carrier. As best shown in FIGS. 4 and 5, the line contact

arms

19 and 21 are normally bent inwardly toward each other by a curve in the base 25 of the contact structure as indicated by the dotted lines in FIG. 2. The element is made of resilient material and the inward flexure of the arms allows the

angled contact ends

20 and 22 to be easily inserted in the corresponding openings 20' and 22' in the bottom of the fuse sockets. .When the screw 29 is tightened to secure the line contact structure to the fuse carrier 10, the curve in the base of the structure is straightened out and the contacts 2t and 22 move outwardly, thereby extending over the edges of the corresponding openings as indicated by the solid lines in FIG. 2. This places a solid support under the

angled contact ends

20 and 22 to support the contact pressure necessary to produce a good. electrical connection between the contacts and their respective fuse Thus, the bend in the contact structure allows it to be easily inserted in place without any sacrifice in the quality of the electrical contact. An ancillary advantage of the uniquely shaped element is that when the curved base is straightened it also serves as a lock washer for the screw 29. It should be noted that the screw 29 could be eliminated by recessing the molded support block 10 so that base 25 can be urged from its initial convex form, slightly past straight, to a somewhat concave shape. If desired, the relationship of bus bar 26 and contact 24 may be reversed (the opposite surfaces from those shown in FIG. 2 being employed) to aid in retaining the concave shape.

The advantages of this invention can be better appreciated by noting that to perform the same function, the prior art structures used at least three separate elements connected together. Each of these prior art contacts was secured by separate fasteners to the fuse carrier member. In contrast, the novel line contact structure of this invention reduces the number of parts required to one. The line contact structure of this invention makes an even more significant reduction in the time required to assemble the device, since it entirely eliminates connections between the contacts. In addition, this novel line contact structure is mechanically and electrically more reliable than the prior art devices, since it does not contain any connections which could become corroded or loosened by vibration. Furthermore, as mentioned previously, the curve in the base of the structure eliminates the need for a lock washer if a screw be used, and also lends itself to a fastener-less assembly. Also, the wiping contact between the bus bar and bus bar contact member significantly expedites the connection and removal of the fuse carrier assembly.

It should be understood that the above described line contact structure is by no means limited to the disclosed embodiment, since modifications can be made without departing from the basic teaching of the invention. For example, the contact element is not limited to two line contacts, as three or more contacts can be provided if desired. Furthermore, the line contact structure is separable from the other aspects of this invention in the sense that it can be used in other fuse carriers, as shown, for example, in copending U.S. patent application Serial Number 291,- 77-1, filed on July 1, 1963, in the names of George H. Phelps et al., for a Fuse Mounting Assembly. This copending patent application shows the above described line contact structure as used in a different multi-position fuse carrier.

The unitary load contact structure of this invention is most clearly illustrated in FIGS. 6 and 7, which show two different configurations of the same basic structure. The load contact structure comprises a single piece of conducting material which is adapted at one end to receive a wire clamping screw and adapted at the other end to be inserted through slots formed in the associated threaded shell. The slots in the threaded shell are formed in the lowermost portion of the side wall, adjacent the bottom, and offset relative to the center of the shell to avoid touching the line contact, which is approximately centered in the bottom of the shell. FIG. 6 shows load contact member 36, which is shaped and dimensioned at one end to enter slots formed in shell 18 and shaped and dimensioned at the other end to receive a connector screw 38. FIG. 7 shows load contact member 49 which is shaped and dimensioned at one end to enter slots formed in shell 16 and shaped and dimensioned at the other end to receive a wire clamping screw 42. Load. contact member 40 is also offset upward at the end nearest shell 16 so that the other end will pass underneath shell 14 with out contacting it, as indicated by the dotted lines in FIG. 2. Both of the load contact members of this embodiment are fitted with

spurs

37 and 41, which are adapted to engage

abutments

44 and 46 of body member 10, as shown in FIG. 3, when the load contact members are inserted through the slots in their respective fuse shells. These spurs are not essential to the invention, but they are desirable, since they help to hold the load contact members in place. When the spurs are used, they are initially for-med parallel with the surface of their respective load contact members, and are bent to engage the associated abutment after the load contact member has been inserted into the slots in the corresponding fuse shell. This operation is very easy to perform, since the spurs are easily accessible from the bottom of the fuse carrier, as shown in FIG. 3.

It should be noted that both load contact members are shaped and dimensioned to completely bypass the openings 16 and 18' in the bottom of their

corresponding fuse shells

16 and 18. This insures that the load contact members will not touch the line contacts within the openings 16' and 18.

The above described load contact members have the obvious advantages of simplicity, reliability, and ease of assembly. They also have several other important advantages in that they eliminate the need for insulators or fasteners for the fuse shell, or insulators between the line and load contact elements. When a fuse is screwed into the fuse shell, it will force the screw shell upward after the button on the bottom of the fuse touches the line contact mounted in the bottom of the fuse socket. This, of course, presses the bottom of the fuse shell against the load contact member extending through the slots therein and provides the pressure to insure good electrical contact between the fuse shell and its load contact member. The load contact member also secures the fuse shell against rotation when the fuse is screwed into thre fuse shell.

The fuse carrier of this invention also contains other improvements which simplify the structure and make it more convenient to assemble. These include the noncircular openings 16' and 1% formed in the bottom of

fuse shells

16 and 18 and the matching non-circular abutments 4% and Sit which project upwardly from the bottom of fuse recesses 12 and 14 and which extend through openings 16 and 18' when the fuse shells are inserted in the recesses. These non-circular abutments and their corresponding non-circular openings key to the slots in the fuse shell so that they will be aligned with the corresponding load contact member when the fuse shell is inserted in its recess. In addition, the abutments 48 and 5t serve as supports for

line contact members

20 and 22 and also as insulating spacers which help insure that the line contact members will be spaced from the load contact members and from the fuse shells. They also help secure the fuse shell against rotation when the fuse is screwed in.

Taken together, the foregoing novel features provide a multi-position threaded fuse carrier which is simple, reliable, inexpensive, easy to assemble, easy to install, and capable of being made by mass production techniques. In the manufacture of the invention, the carrier body member 10which includes sides 34, toes 32,

abutments

44, 46, 48 and 50, the hole for screw 29 (which may be self-tapping), and suitable ledges for holding the contact end of the load contact members in place-is preferably molded in a single piece from a suitable insulating material such a Bakelite or the like. The screw shells can be formed from brass in accordance with well known prior art manufacturing techniques, and the line contact structures can be formed from any suitable resilient conducting material by a simple stamping operation. The load contact elements are preferably made of copper or some other malleable conducting material to expedite the bending of the spurs which help to secure the load contact elements in place. To assemble the fuse carrier, the fuse shells are simply dropped into their respective recesses in the body member, and the load contacts are slid into place through the slots of their respective fuse shells to hold the fuse shell in place. Then the fuse carrier is turned over, and the line contact assemblies are simply dropped into place and secured by their respective screws. This completes the assembly process except for the immobilization of the load contacts. When spurs are used, they are bent to engage their respective abutments either before or after the line contact screws are tightened. If the load contacts are made of a relatively soft metal, this bending operation can be performed by hand pressure with the screw driver which is used to tighten the line contact screws. Alternatively, or even in conjunction with the spurs, screws 50-53 (FIG. 9) may be passed through holes in the fittings and threaded into the Bakelite body. Other arrangements, for immobilizing these fittings, will be apparent to those versed in the art.

From the foregoing description, it will be apparent that this invention provides an improved line contact structure and an improved load contact structure for fuse carriers or the like. It will also be apparent that this invention provides a multiple position threaded fuse carrier which is simple, reliable, inexpensive, easy to install, and capable of being made by mass production techniques. And it should be understood that this invention is by no means limited to the specific structures disclosed herein, since many modifications can be made in the disclosed structure without departing from the basic teaching of this invention. For example, the improved load contact structure of this invention is not limited to use in a plug-in fuse carrier such as disclosed herein. It can be used in any structure which is adapted to receive one or more threaded fuses. Furthermore, the load contact member is not necessarily limited to the particular shape disclosed herein or to the particular material disclosed herein. Many other shapes and materials can be used without departing from the spirit of the invention taught herein. These and many other modifications will be apparent to those skilled in the art, and this invention includes all modifications falling within the scope of the following claim-s.

What is claimed is:

1. In a multiposition fuse carrier having an insulator body containing a plurality of annular recesses, and a plurality of cylindrical threaded conducting shells partially closed at one end to a defined aperture in the center thereof, each axially displaceably mounted in a corresponding recess for accepting a threaded fuse of the type having a load contact on the periphery thereof and a line contact centered at the bottom thereof, the improvement therein comprising: an elongated load contact associated with each said shells, each said contact being adapted at one end thereof to receive a load conductor, the other end extending through the wall of said shell adjacent the base and laterally offset relative the shell axis, said other end further extending through the corresponding recess Wall for limiting the axial displacement of said shell out of said recess; a line contact extending through said shell aperture; and means for limiting the displacement of said line contact in the direction of fuse travel into said shell for transferring the force of a bottoming fuse to an upward urging of said shell against said load contact.

2. The improvement claimed in claim 1 in which said shell has a slot arrangement on the periphery thereof for receiving said line contact therethrough, said improvement further comprising keying means for aligning said shell slot arrangement in a predetermined attitude with respect to said carrier.

3. The improvement claimed in claim 2, in which said keying means comprises a non-circular abutment at the bottom of each said recesses, said shell apertures being correspondingly non-circular to admit said abutment.

4. The improvement claimed in claim 3 in which a portion of said abutment serves as said displacement limiting means, said line contact overlaying said abutment portion.

5. The improvement claimed in claim 1 in which a plurality of line contacts are formed of a unitary structure having a plurality of arms extending into a corresponding plurality of recesses, a common base, and a contact leg emanating from said base in a direction opposite said arms.

6. A line contact structure for fuse mounting assemblies and the like, said line contact structure comprising two line contact members projecting in one direction from a common base and a bus bar contact member projecting in an opposite direction from said common base, said line contact members, bus bar contact member, and common base being formed from a single piece of conducting material, each of said line contact members projecting approximately at right angles to said common base, said common base being curved in a direction which inclines said two line contact members toward each other, said two line contact members having angled ends, a hole formed in said base member to receive an attachment means, two openings formed in said fuse mounting assembly to receive the angled ends of said two line contact members, a flat surface on said fuse mounting assembly to receive said attachment means extending through the hole in said curved base member, said angled end-s being oriented away from each other for overlapping the edge of the corresponding openings in said fuse mounting assembly when said two line contact members are moved from their inclined position to a parallel position, and the securing of said attachment means being operable to flatten the curve in said base member and to move said two line contacts from their inclined position to a parallel position, thereby moving said angled ends over the edges of the corresponding openings in said fuse mounting assembly.

7. A line contact element for a multiposition carrier having receptacles for fuses of the threaded periphery bottom button type comprising a unitary structure including two. arms, the ends of which are flared outwardly from each other and a common base flexibly coupling the other two ends, said flared ends normally being spaced a distance corresponding to the distance between apertures located at the bottom of adjacent receptacles and means for spreading of said arms upon insertion of the flared ends into the corresponding apertures for preventing retrograde thereof.

8. The element claimed in claim 7 in which said arms lie at substantially right angles to said base and the base is curved to incline said arms toward one another.

9. The line contact element claimed in claim 8 in combination with a multiposition carrier having a portion between adjacent receptacles curved opposite the curve in said base; said spreading means including means for forcing said base curve to conform to said carrier portion curve, whereby when the base is flexed to conform with the carrier portion, said arms are forced outwardly, the flared ends thereof overlying the portion of said receptacles adjacent the corresponding apertures.

10. The element claimed in claim 8 further comprising a bus bar contact member projecting from said base in a direction opposite that of said arms, said bus bar contact member, said common base and said arms being formed from a single piece of conducting material.

References Cited by the Examiner UNITED STATES PATENTS 826,152 7/1906 Dale 339162 X 1,158,534 11/1915 Murray. 2,899,521 8/1959 Salomone 200-133 2,961,512 11/1960 Stanback et al. 200-133 X 3,020,373 2/1962 Kobryner et al 200-433 FOREIGN PATENTS 1,124,293 5/ 1955 France. 1,128,433 3/1955 France.

BERNARD A. GILHEANY, Primary Examiner.

A. LEWTTIER, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3 ,261 ,948 July 19, 1966 Herman H. Kobryner et a1.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 5, line 61, for "line" read l oad Signed and sealed this 26th day of September 1967.

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Attesting Officer Commissioner of Patents

Claims

7. A LINE CONTACT ELEMENT FOR A MULTIPOSITION CARRIER HAVING RECEPTACLES FOR FUSES OF THE THREADED PERIPHERY BOTTOM BUTTOM TYPE COMPRISING A UNITARY STRUCTURE INCLUDING TWO ARMS, THE END OF WHICH ARE FLARED OUTWARDLY FROM EACH OTHER AND A COMMON BASE FLEXIBLY COUPLING THE OTHER TWO ENDS, SAID FLARED ENDS NORMALLY BEING SPACED A DISTANCE CORRESPONDING TO THE DISTANCE BETWEEN APERTURES LOCATED AT THE BOTTOM OF ADJACENT RECEPTACLES AND MEANS FOR SPREADING OF SAID ARMS UPON INSERTION OF THE FLARED ENDS INTO THE CORRESPONDING APERTURES FOR PREVENTING RETROGRADE THEREOF.