US2897255A

US2897255A - Shock absorbers for electrical devices

Info

Publication number: US2897255A
Application number: US585858A
Authority: US
Inventors: Robert A Gesellschap
Original assignee: James R Kearney Corp
Current assignee: James R Kearney Corp
Priority date: 1956-05-18
Filing date: 1956-05-18
Publication date: 1959-07-28
Anticipated expiration: 1976-07-28

Description

July 28, 1959 R. A. GESELLSCHAP 2,

SHOCK ABSORBERS FOR ELECTRICAL DEVICES Filed May 18, 1956 IN VEN TOR. ROBERT A. GEJELLJc/MP United States Patent 2,897,255 SH'OCK ABSORBERS FOR ELECTRIC-AL DEVICES Robert A. Gesellschap, Floriss'ant, Mo.-, assignor to James R. Kearney Corporation, St. Louis, Mo., a cor porationof Missouri Application May 18, 1956, Serial No. 585,858

'5 Claims. (Cl. '174"-'163) This invention relates generally to electrical protective devices and more specifically to shock absorbers for electrical cutouts and switches. Electrical devices of the character mentioned are used to automatically open electrical circuits upon the occurrence of abnormal conditions. On short-circuits and other severe circuit abnormalities, the automatic operation of such devices is frequently attended by mechanical shocks of such magnitude as to damage the device as by breaking insulators and bending or breaking metallic parts. Such breakage or bending not only necessitates replacement of the device but may initiate a chain of events which will adversely affect adjacent devices or circuits. Any such device must be so hung on a pole or other support that it isfirmly sustained in adequately spaced relationship, with reference to neighboring devices and conductors, that no part of it can, even under the expected abnormalities, move close enough to affect the operation of neighboring devices. These circumstances dictate rigidity, rather than flexibility, of mounting.

The object of the present invention generally stated is to provide such electrical devices with a shock absorber of a character such as to firmly sustain the device in proper fixed relationship during normal operation and yet permit limited movement to cushion the mechanical shock under abnormal conditons without endangering neighboring devices and conductors. A more specific object of the invention is to provide an electrical fuse cutout or fuse switch which will absorb mechanical shocks caused by rupture of fuses in the operation of the cutouts or switches, and thus avoid bending or breaking portions of the hangers insulators or other parts of said cutouts or switches.

The invention contemplates that electrical devices of the character mentioned be supported by a series of members so inherently rigid and so rigidly connected together that they do not bend or move relatively under the forces to which they are subject in normal operation; and do not bend under the mechanical shock which attends abnormal conditions but do move relatively to a limited extent when subjected to such shocks, and then only in a controlled direction such as to absorb the force of the shock without encroaching upon the air gap between the device and adjacent electrically-live members.

In the accompanying drawings an embodiment of the invention is illustrated in connection with a fuse cutout of the characterdiscl'osed in my co-pending application Serial No. 585,897, filed May '18, 1956. In the drawings:

Fig. 1 is a fragmentary side elevation showing a portion of an insulator of an electrical cutout supported in accordance with the invention.

Fig. 2 is a sectional view taken on line 2-2 of Fig. 1.

Fig. 3 is an enlarged sectional view taken on line 3--3 of Fig. 1.

Fig. 4 is a sectional view similar to Fig. 3 but with the parts of the shock absorbing structure in incompletely assembled position.

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In the drawing the shock absorbing means of the present invention is shown in a form adapted for interconnecting a rigid hanger with an insulator of the type usually employed with fuse cutouts. In such cutouts, as well as many similar devices, an insulator serves as the mounting base for the parts which move to interrupt the circuit (under abnormal conditions) as well as for the fixed contacts and their associated terminals. Usually the arrangement is such that the mechanical shock to which the device is subject upon opening is in the direction indicated by the arrow A, and hence the invention, as shown, is primarily intended to absorb shocks in that direction; but the form shown is equally applicable in cases when the shock is in the direction indicated by the arrow B.

In theembodiment shown, a generally L-shaped hanger 1 is rigidly secured by means of fastening elements 2 to a cross arm or other appropriate support (not shown). The hanger 1 is formed of material and in a manner such as to resist bending in any direction as a result of the forces towhich it will be subject in use, and as shown is of channel section having a web 1 and side flanges 1 In Figs. 1 and 2 of the drawing 3 designates an insulator which forms a part of the cutout, said insulator preferably being of the petticoat type and having formed between adjacent ribs thereof a smooth, annular face 4. Surrounding said insulator 3 at said smooth, annular face 4 thereof is a partially circular portion 5 of a member 5, said member 5 having opposed and spaced legs 6 extended from opposite ends of said partially circular portion 5, the outer end portions 7 of said legs 6 extending inwardly at approximately right angles relative to the legs 6 into lapping relation with respect to each other, as shown to good advantage in Fig. 2. The portions 7 of the legs 6 extend for a distance sufficiently less than the distance between flanges 1 that the two legs 6 may be readily received between said flanges with but little play however. In order to clamp the partially circular portion 5' of the member 5 closely about the insulator 3 and to retain the legs 6 of said member 5 in their proper positions a bolt and nut assembly is employed, the shank of the bolt 8 of said assembly extending through apertures formed through the spaced legs 6, and washers 9 are interposed one between the head 3* of the bolt and one of the legs 6, and the other between the nut and the other of the spaced legs 6. A U-shaped support 10 is interposed between legs 6 with its bight adjacent insulator 3 and its free arms addressed toward end portions 7; and bolt 8 extends through openings in the opposite free arms. The free arms of support 10 thus constitute a stiff spring for absorbing the tension of bolt 8, while the bight portion of support 10 prevents the legs 6 from being drawn together so tightly, adjacent insulator 3, as to break the same.

Thelegs 6 are nested between the flanges 1' at the lower end of hanger 1 and retained therein by means of a cap 11 of channel section having a top wall 11 and a pair of downwardly extended flanges 11 at spacing corresponding substantially with flanges 1 The top wall 11 of the cap 11 is spaced upwardly from the bottom wall 1 of the substantially horizontal leg of the hanger 1 and the side flanges 11 of said cap 11 are in approximate alignment with respect to the side flanges 1 of the substantially horizontal leg of the hanger 1, as shown in Fig. 4. The top wall 11* of the cap 11 and the bottom wall 1 of the substantially horizontal leg of the hanger 1 are provided with apertures 12 which align with each other, and extended through said apertures 12 is the shank of a bolt 13. The shank of the bolt 13 is embraced throughout a predetermined part of its length by a tubular member 14 and the apertures 12 are of size such as to accommodate said tubular member.

A resilient cushion which may be a spring, but is shown as a block 15 of rubber or the like is provided above cap 11, and said rubber block has a central aperture for accommodating tubular member 14, a rigid washer 16 overlyin the top face of said block of rubber 15 and the top end of said tubular member 14, and being interposed between them and the head 13' of the bolt 13. Also a second rigid washer 17 is interposed between the bottom face of the bottom wall 1 of the substantially horizontal leg of the hanger 1 and a nut 18.

In the drawing Fig. 4 illustrates the shock absorber of this invention before it has been drawn down taut into its operative position shown in Fig. 3. It will be noted that in Fig. 4 the block of resilient material 15 is in an expanded condition, and that the cap 11 is raised slightly with respect to the substantially horizontal leg of the hanger 1. To complete the assembly, the nut 18 is screwed up on the shank of the bolt 13 thereby moving said bolt 13 and washer 16 downwardly and compressing the block of resilient material 15 as shown in Fig. 3, the tubular member, which contacts with the under face of the washer 16, moving downwardly with said washer 16 until it abuts against and is stopped by contacting with the top face of the washer 17 (see Fig. 3) thereby arresting the compression of the block of resilient material 15. As the bolt 13 and washer 16 move downwardly as described, the cap 11 is likewise moved downwardly to confine the spaced legs 6 of the member 5 between said cap and the substantially horizontal leg of the hanger 1.

With the construction described the dimension (circumferentially of the insulator) of the bight portion of support is such as to prevent the legs 6 from being drawn so close together, adjacent the insulator, as to impose a strain on the insulator; yet the resilience of the free arms of the support 10 is such as to permit bolt 8 to be drawn up so tightly that the legs 6 are slightly bowed.

With the construction described, the length of tube 14 limits the extent to which the nut 18 may be threaded on bolt 13 and thereby limits the degree to which block 15 may be thereby compressed. Thus by coordinating the resilience of block 15 with the length of tube 14 the magnitude of the force required to flex the connection may be predetermined, and this assures that the con- 7 nection will have the desired rigidity against forces less than that magnitude, provided the nut 18 be threaded up to the point where tube 14 abuts washer 16 at the top and washer 17 at the bottom. Mechanical shock (created by rupture of the fuse link of the electrical cutout or switch) of magnitude such as to break the insulator or other parts, is thus absorbed by the block of resilient material 15 whereas the connection remains rigid against lesser forces. When subjected to shocks which cause the connector to flex, however, the relative movement between hanger 1 and member 5 is limited both in degree and direction. The degree of such movement is limited by the compressibility of block 15 beyond the position shown in Fig. 3 which in any event is insufficient to un-nest arms 6 from between the flanges 1 and 11 Moreover, the direction of such movement is directionally limited by flanges l and 11 together with arms 6 which are held adjacent said flanges by angular portions 7. By limiting both the degree and direction of flexing movement, the hazard of adversely affecting adjacent devices or conductors is minimized.

Having thus described the invention, what is claimed and desired to be secured by Letters Patent is:

1. The combination with an electrical device having a relatively rigid hanger for supporting the same in place for use, of a member rigidly fixed to a part of said electrical device, a channel-shaped portion formed on said hanger, a cap arranged in spaced relation with respect to said portion of said hanger, said cap being in the shape of a channel inverted with respect to and aligned with said portion of said hanger, parts of said member being compressedly held between said portion and said cap, a resilient element, and means extending through openings formed through said cap and through said portion of said hanger and extending through said resilient element for compressing said resilient element.

2. The combination with an electrical device having a relatively rigid hanger for supporting the same in place for use, of a member rigidly fixed to a part of said electrical device, a channel-shaped portion formed on said hanger, a cap arranged in spaced relation with respect to said portion of said hanger, said cap being in the shape of a channel inverted with respect to said portion of said hanger, parts of said member being compressedly held between said portion and said cap, a resilient element, means extending through openings formed through said cap and through said portion of said hanger and extending through said resilient element for compressing said resilient element, and means for limiting the compression of said resilient element by said first mentioned means.

3. The combination with an electrical device having a relatively rigid hanger for supporting the same in place for use, of a member rigidly fixed to a part of said electrical device, a channel-shaped portion formed on said hanger, a cap arranged in spaced relation with respect to said portion of said hanger, parts of said member being compressedly held between said portion and said cap, a resilient element, and means extending through openings formed through said cap and through said portion of said hanger and extending through said resilient ele ment for compressing said resilient element, said member being internested in said channel-shaped portion of said hanger and retained therein by said means irrespective of the condition of said resilient element.

4. The combination of claim 3 wherein said member has a pair of legs extending adjacent the flanges of said channel-shaped portion, and means for maintaining said legs spaced apart toward said flanges respectively.

5. The combination of claim 4 wherein said member embraces an insulator portion of said electrical device and said means for maintaining said legs spaced apart is located both adjacent said insulator portion and outwardly therefrom at a position embraced by said flanges.

References Cited in the file of this patent UNITED STATES PATENTS 1,814,831 Covey July 14, 1931 2,139,332 Pittman et al. Dec. 6, 1938 2,160,808 Bradley June 6, 1939 2,308,969 Riesing Jan. 19, 1943 2,331,258 White et a1. Oct. 5, 1943 2,399,414 Wells et al. Apr. 30, 1946 2,589,726 Neufeld Mar. 18, 1952 2,673,059 Lustig Mar. 23, 1954