US3264443A

US3264443A - Explosion-proof switch box assembly including reciprocal external actuator means

Info

Publication number: US3264443A
Application number: US324398A
Authority: US
Inventors: Joseph J Farina; Marshall G Zavertnik; James A Kelly
Original assignee: Killark Electric Manufacturing Co
Current assignee: Killark Electric Manufacturing Co
Priority date: 1963-11-18
Filing date: 1963-11-18
Publication date: 1966-08-02
Anticipated expiration: 1983-08-02

Description

Aug. 2, 1966 J. J. FARINA ETAL 3,264,443

EXPLOSION-'PROOF' SWITCH BOX ASSEMBLY INCLUDING RECIPROCAL EXTERNAL ACTUATOR MEANS Filed Nov,. 18, 1963 7 @l ,3 o f HTTORNEY United States Patent O 3,264,443 EXPLOSION-PROOF SWITCH BOX ASSEMBLY IN- CLUDING RECIPROCAL EXTERNAL ACTUA'IOR MEANS Joseph J. Farina, Bridgeton, Marshall G. Zavertnik, Manchester, and James A..Kelly, St. Louis, Mo., assignors to Killark Electric Manufacturing Company, St. Louis, Mo., a corporation of Missouri Fiied Nov. 18, 1963, Ser. No. 324,398 10 Claims. (Cl. 200-172) The present invention relates to a switch box assembly and particularly one that is designed to be explosionproof and weather-proof.

In general, the assembly includes an explosion-proof box in which electrical switches are mounted, with linearly operating actuators on the outside of the box and extending through a wall by explosion-proof bushings, The box can be made of an aluminum casting of appropriate wall thickness to prevent and contain explosions. The box has the necessary number of threaded ports for conduits through which wire connections can be brought into the box. Within the box are a plurality of switch mounting clips that can be easily attached to an inside wall of the box, and can hold the electrical toggle switches all in a line so that their actuating means operate linearly in parallel directions. Consequently, the portions of the actuating means that extend from the inside to the outside of the box are all parallel. The actuating means are identical. The actuating means can be locked in either position of the toggle switches.

A principal object of the invention is to provide an assembly of this kind that has maximum flexibility so that it can take a maximum number of different combinations and arrangements of switches with a minimum number of parts. Specically, it is an object of the invention to provide an assembly of this kind in which conventional toggle switches may be used and actuated from outs-ide of an explosion-preventing receptacle or box. In this connection, it is an object to provide actuators that can pass from the outside of the box to the interiorly mounted toggle switches, which actuators are of simple construction and yet which are dependable -in operation as well as fire-proof and explosion-proof. Another object is to provide such an arrangement in which any number of actuators can be applied to a given sized box provided with any number of switches mounted within the box by the simple expedient of filling and tapping the box for the appropriatae number of actuators and switch mountings. A further object is to provide an assembly that can be put togther and taken apart with ease.

Other objects will appear from the description to follow.

Referring to the drawings:

FIGURE l is a plan view of the switch box assembly;

FIGURE 2 is a similar plan view, but with the cover removed, exposing the toggle switches within the box;

FIGURE 3 is an end view taken from the right end shown in FIGURES l and 2;

FIGURE 4 is a transverse section taken approximately on the line 4-4 of FIGURE 1 show-ing one of the switches in its outer position;

FIGURE 5 is a somewhat enlarged fragmentary view of the switch-operating means shown in FIGURE 4, but with the switch operating means in its inner position;

FIGURE 6 is a top view of one of the switch-locking brackets; and

FIGURE 7 is a bottom view of the bracket.

The box 10 is here illustrated as being made of an aluminum casting with walls approximately one-half inch thick, so as to withstand explosions. Preferably the entire box is made in a single casting, with an upstanding ice round cover opening 11 that is internally threaded to receive a round and threaded cover 12 that screws into the opening 11. The cover has a flange 13 projecting outwardly from its threaded portion, the flange engaging over a gasket 14. By this arrangement the cover may be threaded in place, compressing the gasket that with the threads forms an explosion-proof joint. The cover can have appropriate radial ribs 15 forming means by which it can be turned to screw it or unscrew it. The box also can be provided with integrally cast attaching ears or lugs 17 to receive screws by which it can be attached to an appropriate support. It may also have an appropriat-e number of threaded

openings

18, 19 and 20 into which wire-containing conduits may be screwed so that wires maybe brought to the interior of the box for attachment to the switches.

In FIGURE 2, four

switches

22, 23, 24 and 25 are illustrated as mounted in the switch box. Other numbers, of course, may be used as needed.

The switches are identical, so that a description of the switch 23 will suice for all. It is provided with

anges

27 and 28 at opposite ends adjacent its bottom. A spring clip 31 is secured by drive screws or the like to the bottom of the box 10. This spring clip 31 has a hook end 32 at one end and a similar hook end 33 at the other. However, the hook 33 has an outwardly-extending linger grip end 34, that is joined to the hook end 33 by a hairpin bend, somewhat rounded to facilitate installation of the switch as will be evident. Pressing the linger end 34 rmly toward the bottom of the box releases the hook from the iiange 27 and permits the switch to be removed or installed. The switch has a conventional toggle arm 37 projecting out of its top side.

Thus it can be seen that the desired number of spring clips 31 can be mounted on the bottom floor of the box 10 by self-tapping screws and then the switches can be readily clipped into place, aided if necessary by depressing the outstanding finger'ends 34 on the clips. Once the switches are in place, the overhanging ends of the clips hold them securely. Access to the interior of the box for all of the foregoing is readily available because of the large size of the threaded opening when the cover 12 is removed.

Actuating means 38, 39, 40 and 41 are provided for actuating the

respective switches

22, 23, 24 and 25 from the exterior of the box. These are all the same and description of the actuator 40 illustrated in FIGURES 4 and 5 will suffice for all of them.

The toggle arm 37 of the switch 23 moves to the left and right in the drawings. An actuator rod 43 is slidably mounted in an elongated bushing 44 that is threaded tightly into an opening in the wall of the box. These parts, as illustrated, are in a line to accord with the line of operating movement of the toggle arm 37. The bushing is of sufficient length to provide flame suppression around the rod 43.

Inside the box, the rod 43 has a ilattened end 45, onto which a flat toggle bracket 46 is attached by a screw 47. The bracket 46 has a rectangular hole 48, through which the toggle arm 37 extends. The edges of the hole 48 that may Ialternately engage the toggle arm, are depressed somewhat for better engagement of the toggle arm.

To reciprocate the rod 43 in and out, a handle 50 is attached onto a reduced outer end portion of the rod 43, and retained by a snap-ring 51 applied transversely to the rod, as indicated. A Walds Tru-Arc Bowed E type retainer is satisfactory, and provides a secure, rigid, connection of the handle.

The handle 50 tits through a hole S4 in a shelf 5S of a locking bracket 56 show-n separately in FIGURES 6 and 7. The bracket has a vertical end wall secured against the outside of the wall of the box lll by the flange on the bushing 44, the mounting being stabilized against twisting by a screw 57. The bracket also has side walls S8 and 59 for giving is stability. In `addition to the large hole 54, through which the handle t) extends, the shelf 55 has a small hole 60. The handle 50 has a projecting ledge 61 overlying the shelf 55, and provided with a hole 62. In assembling the present assembly, a box 10 of suicient size to receive the desired number of switches is chosen. Usually the same box can be used for a number of switches such as one to four. The box can be drilled and tapped as at 18, 19 and 20 for the appropriate arrangement of the conduits that are to bring the wires to the switches. Normally each box `will have at least two such tapped holes in it, the ones not to be used being plugged by threaded plugs that eliminate the flame hazard.

A mounting spring bracket 31 is fastened to the bottom of the box for each of the switches to be employed. Then the switches are snapped into place, being retained by the clips 31. The wire connections should be attached to the switches before the actuators are mounted.

An appropriate number of actuators 39 are provided, the box being readily drilled and tapped for each desired actuator bushing 44. A locking bracket 56 is placed onto each bushing 44 to he held in place when the latter is screwed in tightly. The bracket is stabilized by a screw 57. The rod 43, tting through the bushing 44, with its handle 5t) in place, can then have its toggle bracket 46 secured on by the screw 47.

If it becomes necessary to replace a switch, the operator removes the toggle bracket 46, depresses the tongue 34 to release the spring clip, and then can remove the switch. It may be necessary to remove the middle switches to get at the ones at the side. Replacement is equally easy, since a switch can be hooked under the Clip hook 32 and then-pressed against the hook 33, which yields to enable the switch to lock in place.

. In use of the equipment, the switches can be locked in either inner or outer positions. A lock can be passed through the aligned

holes

60 and 62 as shown in FIG- URE 4, to retain the switch in outer position. A lock can be passed through the aligned

holes

54 and 62 as shown in FIGURE 5, to retain the switch in inner position.

The opening 54 has a generally rectangular shape, as shown in FIGURES 6 and 7. It can limit reciprocal movement of the handle 50, thereby preventing injury to the switch by excessive force against the toggle arm 37.

One of the features of the present invention is that -the parts are extensively standardized. All of the actuators can be identical, and this is true whether the toggle switches be single-throw or double-throw siwtches, or what combinations are employed. Also the arrangement lends itself to the use of toggle switches, rather than torque' switches, which is an advantage from the standpoint of simplification of equipment.

Various changes and modifications may be made within the process of this invention as will be readily apparent to those skilled in the art. Such changes and modifications are within the scope and teaching of this invention as defined by the claims appended hereto.

What is claimed is:

1. In an explosion-proof box assembly: a box having an access opening in one side, and a cover removably mounted on the box to close the opening; at least one switch mounted in the box, removal of the cover from the opening giving access to the interior of the box for the securing of the switch therein; the switch having an element adapted to be actuated by reciprocal movement; an actuator for the switch extending across the-switch between it and the opening in the box, including a rod extending through a hole in the wall of the box and movable into and out of the box; a handle on the rod, outside the box, larger than the hole, by which the rod may be' pressed into and withdrawn out of the box in a straight-line movement; means normally limiting the withdrawal movement of the rod, comprising a switchelement-engaging member removably secured to the end of the rod adjacent the switch, and adapted to embrace the switch element to enable reciprocal movement of the handle and rod both Ways, to actuate the switch, and being removable to permit the switch to be removed or installed in the box.

2. The assembly of claim 1, wherein there is a locking bracket on the outside of the wall of the box adjacent the hole, and the bracket and handle have cooperating means to receive a lock when the handle is in each of its inner and outer positions. 3. The assembly of claim 2, wherein the locking bracket is removable from the `box to facilitate removal of the rod from inside the box.

4. The assembly of claim 3, wherein the locking bracket has means limiting inward and outward movement of the rod, and cooperating means with the handle for receiving a lock for locking the handle in inner or outer position.

5. The assembly of claim 2, wherein a bushing is threaded into the hole in the box from the outside surrounding the rod, and has a flange engageable with the locking bracket to clamp the locking bracket against the wall of the box.

6. The assembly of claim' l, wherein the switch has ledges adjacent its bottom, and the means for holding it in place comprises a spring clip secured to the box, the clip having spring-like overhanging ends releasably engageable over the ledges of the switch.

7. In a switch assembly, a box, a switch in the box having an operating member operable by back and forth movement; a rod slidably mounted through a wall of the box, means on the inner end of the rod engageable with the switch operating member to move it back and forth upon reciprocation of the rod back and forth; a handfe on the rod outside the box; a bracket on the box adjacent the handle, the bracket having limiting means limiting inward and outward movements of the handle and rod, and openings in the handle and bracket to receive a lock to lock the handle, and therefore the switch, in inner or outer position.

8. In a switch assembly, a box, a spring clip having a first hook at one end and a second hook at the other end, the second hook having a depressible tongue that can be depressed to spread the hooks apart; the clip being secured to an inner wall in the box with the ends outstanding from the wall; a switch having opposite ledges, one engageable under the iirst hook, and the other engageable under the second hook to hold the switch securely in place in the box, the second hook having a curved tongue that cams the second hook around the ledge on the switch when the switch is pressed against the second hook; and actuating means for the switch including a member movably mounted through the wall of the box and projecting outside the same to be accessible for operating the switch.

9. In a switch assembly, a switch box, a switch actuator including a rod; the box having a hole through a wall through which the rod passes, a bushing surrounding the rod and holding it for reciprocating movement, the bushing having threads on its outer surface threaded into the hole and an enlarged flange at one end; a locking bracket mounted over the bushing, having a hole receiving the bushing but smaller than the flange, whereby the bushing holds the bracket against the box, the bracket having a ledge with a main hole through it, a switch actuator handle having a portion extending through the hole to below the ledge and there attached to one end of the rod; the hole being larger than the part of the handle passing through it and the handle movement being limited by th-e ends of the hole in the ledge;

in place.

UNITED References Cited by the Examiner STATES PATENTS Brachti 200-172 Hardage 20G-168 Blood 200--172 Bissell ZOO-168 McKitrick ZOO-169 X Taylor 200-172 X Kobryner 317-119 X Lasar 20G-*172 Johnson 317-120 X OTHER REFERENCES Millerwise, German printed application No. 1,147,287,

10 ROBERT K, SCHAEFER, Primary Examiner.

BERNARD A. GrLHEANY, KATHLEEN H. CLAFFY,

Examiners.

H. O. I ONES, Assistant Examiner.

Claims

7. IN A SWITCH ASSEMBLY, A BOX, A SWITCH IN THE BOX HAVING AN OPERATING MEMBER OPERABLE BY BACK AND FORTH MOVEMENT; A ROD SLIDABLY MOUNTED THROUGH A WALL OF THE BOX, MEANS ON THE INNER END OF THE ROD ENGAGEABLE WITH THE SWITCH OPERATING MEMBER TO MOVE IT BACK AND FORTH UPON RECIPROCATION OF THE ROD BACK AND FORTH; A HANDLE ON THE ROD OUTSIDE THE BOX; A BRACKET ON THE BOX ADJACENT THE HANDLE, THE BRACKET HAVING LIMITING MEANS LIMITING INWARD AND OUTWARD MOVEMENTS OF THE HANDLE AND ROD, AND OPENINGS IN THE HANDLE AND BRACKET TO RECEIVE A LOCK TO LOCK THE HANDLE, AND THEREFORE THE SWITCH, IN INNER OR OUTER POSITION.