US1851249A - Terminal for inclosed fuse cut-outs - Google Patents

Description

March 29, 1932.. H, J, HAMMER 1,851,249

TERMINAL FOR INCLOSED FUSE CUT-OUTS- Filed D80. 12, 1930 INVENTOR Patented Mar. 29 1932 UNITED STATES PATENT OFFICE PZEBML'N J. HAMMERLY, OF WALLINGFORD, CONNECTICUT, ASSIGNOR TO THE TBUIMBULL ELECTRIC MANUFACTURING COMPANY, OF PLAINVILLE. CONNECTI- CUT, A CORPORATION OF CONNECTICUT 'rnaiunmnron iwonosnn FUSE cur-ours Application filed December 12, 1930. Serial No. 501,779.

My invention relates to means for clamping the terminals of inclosed fuses in position in co-related fuse jaws.

It relates particularly to means for insuring a positive electrical connection between the fixed and removable members for positively maintaining the fuses in operable position,

The form I have chosen to illustrate applies particularly to the type of fuses which is provided with terminals of the knife blade type,-

although it is applicable to other types.

It has been the practice to provide a pair of spaced jaws to receive each terminal of fuses of this type, the jaws often being soldered in position and mounted so as to project from a suitable foot block. In this usual type they have their projecting ends slightly bent orsprung together so as to provide a resilient engagement with the fuse terminals.

Fuse jaws of this type are usually made of copper or copper alloys, because of their high electrical conductivity, but the resilient property of these metals is limited and easily destroyed in case of continued and/or excessive heat arising from poor electrical contact while in service, or other causes. It is possible to mount and assemble the various parts of the fuses and the contact jaws at the factory so that the contacting engagementwill be substantially perfect but, in shipping and subsequent handling, the jaws are uite likely to become more or less bent and t e' terminals of the fuses are V apt to be bent considerably out o alignment,

. so that by the time the fuse is put into service it is often the case that the co-related parts will make a very poor electrical connection. Due to im erfect contacts it often arises that such conditions will result in one or more 40 of the following undesirable conditions:

An undue resistance is set up in the circuit resulting in a drop in voltage and a consequent loss of ower. v I The so may blow at a point far below its rated capacity, due to this waste dpower appearing asheat which may be,con ucted into the fusible element of the fuse and thus cause an unnecessary shut down of the power and heavy pecunia loss. I

Because of t e undue heating of the fuse particularly terminals the fuse strips may blow at the point where they are secured to the blade terminals instead of at the center of the strip which is usually notched to insure the blowing or fusing at a point or points substantially midway between the knife blade terminals where the strip is usually surrounded by granular insulating material and this condition often causes the burning of the fuse caps and terminals as well as the detachable fastening means which are used in fuses of the renewable type.

The are caused by an imperfect contact tends to pit or corrode and oxidize the parts, thus destroying their mechanicalfitting as well as their electricalconductivity.

The undue heat tends to draw the temper and destroy the resiliency of the contact jaws which is usually relied upon to maintain a good contact and to hold the fuse in position.

Fuse jaws of some types are sweated or soldered into corresponding slots in the supporting foot blocks and undue heating of the jaws tends to melt the solder and results in a dangerous condition. 7

In fuse terminals of the type which includes copper jaws, the jaws are necessarily comparatively thin in order to provide the required resiliency but these thin jaws are much more quickly heated and transmit the heat to the fuse body much more readily than is desirable.

A principal object of my invention isto overcome or minimize these difficulties of the common-types of fuse terminals which have just been pointed out.

Another object of this invention is to minimize the generation of heat at the point of contact between the fuse blades and the contact jaws or clips, and to provide good thermal conductivity and dissipative capacity for radiating such heat as may be generated.

Another object is to prevent undue rise of temperature of the fusible strip of the fuse, by the conduction of heat thereinto because of defective contacts.

A further object is to prevent fuses from blowing out below their rated capacity, by

reason of surplus heat being conducted thereinto and exerting upon the fusible member of the fuse a melting action additive to the normal action due to the passage of current therethrough.

Another object of my invention is to confine the fusion of the conducting member therein substantially to the portion thereof which is designed to dissipate the energy liberated upon rupture of the same by excessive current.

Another object is to protect a fuse from having its fusible link melt adjacent to either of its end terminals.

A further object is to prevent pitting of contact by circuit ruptures occurring at portions of the fuse closely adjacent thereunto.

A further object of my invention is to provide a form of fuse terminal in which the contact ends of the fuse may be securely clamped to insure positive contact and to secure the fuse in position and yet may be easily and quickly removed by means of a common screw-driver.

Another object is to provide a fuse clamping means including angularly disposed'jaws from which the fuse is entirely freed for ready removal when the clamping member is released.

Another object is to provide a fuse terminal which is entirely free of soldered or pinned-together parts.

Another object is to provide an unusually rugged one-piece fuse terminal which may be depended upon for long service and to safely carry the current up to the full rated capacity of the fuses.

Another object is to provide a fuse clamping means which is capable of correctly ali ing the contact blades of a fuse with the use jaws even though these blades were not properly aligned at the factory or have become disarranged in handling.

Another object is to provide a fuse terminal having a one-piece jaw member so designed as to provide an unusual amount of metal and surface for absorbing and for radiating any heat caused by abnormal conditions in the electrical circuit.

Another object is to provide a fuse clamping means including a roll or cam member which is loosely mounted at its center so that it is free to adjust or align itself with respect to the contact end of the fuse and to allow for a considerable wear of the cam itself or of the angular surface of the co-related jaw member.

Fig. 1 is a front view of a cartridge type fuse mounted in supports involving my invention.

Fig. 2 is a fragmentary sectional view on the plane of the line 22 of Fig. 1 and showing an end view of one of the supports.

Fig. 3 is a similar view of a modification.

A typical cartridge type fuse 5 has the usual terminal blades 6-6.

The support 7 is secured to the base or panel 8 by screws such as 9 and 10 and the latter may also serve as an anchorage for the conductor terminal 11 The supporting member 7 has two flanges 12 and 13 which are integral with the base of the su port and spaced sufliciently apart to receive etween them the blade 6 of the fuse and a wedging member 14.

In the form shown in Figs. 1 and 2, the wedging member 14 is cylindrical and mounted on a screw threaded adjusting member 15 which is adjustable in the base of the support by mere rotation of the screw, so as to move the wedging member in or out as the case may be. The inner walls of the flanges 12 and 13 in this form are tapered or inclined and converge toward each other and toward the bottom of the space between them.

By properly proportioning the parts it will be seen that the blade 6 can be forcibly pressed against the flange 13 by the simple expedient of tightening the screw 15 which draws the mem port.

In View of the fact that the two flanges 12 and 13 are substantially rigid it will be seen that there is practically no limit to the pressure which can be applied to produce contact between the blade 6 and the flange 13. The only part upon which there is any wear is the screw 15 which can be readily replaced.

As the device is not dependent upon the resiliency of the usual spring jaws or clips it will be obvious that heat will have but little if any effect upon the contacts.

It is also obvious that there is no danger of the fuse being accidentally disengaged. No amount of vibration will loosen the fuse when it has once been properly inserted.

In the form shown in Fig. 3 the su port or holder has two flanges 12 and 13'. e inner wall of the flange 12 is inclined and the other flange is at right angles to the base 7. In this case I have shown a wedge shaped member 14' inserted between the inclined face of the flange 12 and the base 6. This member 14 can be forced into place in any suitable manner so as to produce an increased area of contact.

While it is desirable to employ a. wedging member which is of conducting material it should be understood that some of the advantages of m invention might be attained with a non-con ucting wedge which can be forced or expanded into the space between the fuse blade and the opposite rigid wall or flange of the holder.

I claim:

1. A fuse holder including a metallic base having two flanges spaced apart from each other and projecting perpendicularly from the base, an adjustable wed ing member between said flanges, a screw aving a threaded engagement with the base and passing freely t er 14 into the narrow throat of the suprough said wedging member and 2. A fuse holder including a metallic base.

member having two flanges projecting perpendicularly therefrom and spaced apart from each other to receive between them the terminal blade of a fuse, at least one of said flanges having its inner face inclined with respect to the opposing face of the other L flange, a loosely mounted wedging member movable toward and from the base, and means accessible from a point adjacent the outer ends of the flanges for operating the wedging member to clamp the terminal blade of a fuse.

8. A fuse terminal clamp including a metal base having two perpendicularly projecting spaced walls to receive between them a fuse blade, a self-aligning wedging means 1 located between said walls for clamping a fuse blade against one of said walls, said wedging means including a member having convex side walls, said member being movable toward and from the base and laterally with respect to said walls and adapted to tilt endwise, and means accessible adjacent the outer ends of said walls for operating said wedging means.

4. A fuse terminal clamp including a metal base member havin two spaced flanges projecting therefrom an having oppositely disposed faces, the opposing face of one flange having a flat fuse terminal clamping surface and the opposing face of one of said flanges projecting angularly from said base with respect to the opposing face of the other flange, a projecting screw seated in said base with its head between the opposing faces of said flanges, a substantially cylindrical clamping bar having a rockable engagement with said screw and movable to clamp the terminal of a fuse against the opposing'face of one of said flanges.

5. A fuse clamp including a metal base plate having two spaced flanges projecting perpendicularly from said plate, each of said flanges having a flat face opposed to the face of the other flange and' the face of one of said flanges being inclined with respect to the face of the other flange, a clamping screw having a threaded engagement in said base plate between said flanges and projecting from said base plate, a clamping bar positioned between the opposed faces of said flanges and means of connection between said bar and said screw for causing the clamping or unclamping movement of said bar by the rotary movement of said screw.

6. A fuse terminal clamp including a metal base having two integral spaced flanges projecting perpendicularly therefrom, said flanges having opposing faces, one of said faces having a flat surface and one of said faces being inclined with respect to the face of the other flange, a clamping screw seated in said base with its head between said flanges and projecting from said base, a clamping bar tiltably engaged by said screw and movable between said flanges by the turning movement of said screw to clamp the terminal of an inclosed fuse between said flanges.

7. A fuse terminal clamp including a metal base having two spaced flanges pro] ecting therefrom and having opposed faces, the opposed face of one of said flanges being adapted for electrical engagement with a terminal of an inclosed fuse, the opposed face of the second flange being spaced apart from the said face of the first defined flange with a socket between the flanges to receive the terminal end of a fuse, and screw means projecting substantially perpendicularly from said base between said flanges and laterally movable by engagement with one of said flanges and having a laterally projecting portion to extend over a part of and force a terminal of an inclosed fuse into engagement ylvith the opposite face of said first defined ange.

8. A fuse terminal clamp including a metal base having two spaced flanges projecting substantially perpendicularly therefrom and with a socket between them for reception of the terminal end of a fuse, one of said flanges having a face adapted to make electrical contact with the terminal of an inclosed fuse, the other flange having a face angularly inclined with respect to the said face of the first defined flange and screw means projecting perpendicularly from said base adjacent to said inclined flange and positioned between the respective flanges, said screw means having an operating-end accessible at the front of the socket and being movable laterally by engagement with said inclined flange toclamp a terminal of an inclosed fuse against said face of the first defined flange.

HERMAN J. HAMMERLY.

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