US2015543A - Interlocked explosionproof switch housing and plug receptacle - Google Patents

Description

Sept. 24, 1935. c. H. BISSELL 2,015,543

INTERLOCKED EXPLOSIONPROOF SWITCH HOUSING AND PLUG RECEPTACLE Filed July 21, 1933 Patented Sept. 24, 1935 UNITED STATES PATENT OFFICE INTERLOCKED EXPLOSIONPROOF SWITCH HOUSING AND PLUG RECEPTACLE poration of New York Application July 21, 1933, Serial No. 681,547

3 Claims.

This invention relates to an explosion proof switch housing provided with a plug receptacle with means for preventing operation of the switch when the plug is withdrawn from the receptacle, and means for preventing withdrawal of the plug from the receptacle after the switch has been actuated to the on position.

The invention consists in the novel features and in the combinations and constructions hereinafter set forth and claimed.

In describing this invention, reference is had to the accompanying drawing in which like characters designate corresponding parts in all the views.

Figure 1 is a lengthwise, sectional view of the explosion proof switch housing, parts in elevation, and the plug withdrawn from the receptacle.

Figure 2 is an end elevation of the switch housing cover and part of the switch operating mechanism.

Figure 3 is an end elevation of the receptacle housing, partly in section.

Figures 4 and 5 are partial sectional views, similar to Figure 1, showing the position of the locking mechanism when the plug is inserted in the receptacle, and the switch operating mechanism is in the off and on positions respectively.

Explosion proof fittings are designed particularly for use in hazardous locations. That is, where, on account of the surrounding atmosphere containing inflammable gases, a spark from an electrical apparatus would be likely to cause an explosion. As a caution against such explosions, explosion proof fittings are so constructed that the contact mechanism of the fitting is enclosed in a tight housing which is of such structure that should any gases explode within the housing they will be cooled below the ignition point before reaching the outer atmosphere. Obviously, in the use of plug and receptacles, it becomes necessary to provide some means whereby the circuit will not be closed, or opened, by the separation of the plug and receptacle contacts.

This invention comprises generally, the combination of an explosion proof switch housing and a receptacle housing, a receptacle mounted in the receptacle housing and connected to and controlled by the switch in the switch housing, the switch housing being provided with switch operating mechanism to shift the switch into on and. off positions, and means coacting with the plug and the switch operating mechanism and being operable upon withdrawal of the plug from the receptacle toprevent operation of the switch operating mechanism, and to prevent withdrawal of the plug after the switch operating mechanism has been shifted to on position.

Referring to the drawing, Ill designates the explosion proof switch housing which may be of any suitable form. As here shown, it comprises 5 a rectangular box with base H, and end wall l2 perpendicular to the base and provided with a threaded opening l3 to receive the conduit carrying the electrical circuits. The opposite end projects outwardly from the main portion of the 1g housing at a substantial angle to the base H. The side opposite the base I l is open, and is provided with a cover or cap I 4, and is secured to the housing l2 by a plurality of screws 15. The coacting marginal faces of the housing and the cap 35 M are generally ground to a true accurate surface.

The angular end portion IB is provided with a receptacle housing l8 which is secured to the end portion 15 in a manner similar to the attach- 20 ment of the cap I4 to the housing, namely by screws extending through the holes l9 and threading into bosses formed in the angular end portion [6.

A plug receptacle 20 is secured to a plate 2| 25 which is clamped between the receptacle housing 18 and the end portion l6 of the switch housing. These coacting surfaces are also ground true so as to limit the. escape of any gases ignited within the switch housing. The receptacle 20 is pro- 30 vided with a plurality of terminals or contacts 22 which are in turn electrically connected to and controlled by a switch 23 by means of the wires or conductors 24. The switch 23 is secured in the housing [2 in any suitable manner. As 35 here shown, the switch 23 is secured to a plate 23 which extends across the open side of the housing, and its ends are secured in recesses 25 by screws, or other fastening means.

After the receptacle housing 58 has been se- 40 cured to the end !6 of the switch housing, and the receptacle 253 and plate 2| secured in place, the end it of the switch housing is filled with a suitable sealing compound, as indicated in Figure 1 of the drawing. This establishes a tight joint be- 45 tween the receptacle 29 and the conduit line entering the switch housing through the passage 23. The switch 23 is provided with an operating member 26 which is pivotally mounted in the switch proper and shiftable crosswise of the hous- 50 ing to operate the switch into on and off positions.

The switch housing is provided with switch operating mechanism operable from the outside of the housing. This mechanism comprises a shaft 55 30 journalled in a boss 3| formed in the upper portion of the cover I4. To the inner end of the shaft 33 is secured a yoke member 32, the fingers of which cooperate with the switch operating element 26 in such a manner that upon rocking the shaft 30, the element 26 is actuated to shift the switch into its on or off position. The outer end of the shaft 30 is provided with an operating manual 33 having a hub 34. The hub 34 is provided with a slot or recess 35 extending perpendicular to the axis of the shaft 30 and so formed relative to the yoke 32 that it assumes a perpendicular position when the switch is actuated to the off position.

The receptacle housing I8 is provided with an arcuate portion 36 which terminates in a plane parallel with the face of the hub 34, and is formed with a passage or chamber 38. A look member 40 is pivoted in the chamber 38 upon the shaft 4| which extends crosswise thereof. A coiled spring 42 surrounds the shaft 4| and has one end connected to the member 40, and the other end to the portion 36, and normally rotates the member 40 clockwise in the position shown in Figure l.

The lock member 40 is so arranged relative to the shaft 30 that it rotates in a plane perpendicular to the axis of the shaft 30, or so that the inner end travels, upon rotation, through the slot 35 formed in the hub of the manual 33. The bottom of the slot 35 is formed arcuate and concentric with the axis of the shaft or pin 4|. The inner end of the member 40 is generally arcuate in shape, being truncated, or flattened oif, as at 46 so when it assumes the position shown in Figures 4 and 5, the end 44 does not extend into the slot 35. It will be observed that normally the shaft 30 can not be rotated to actuate the switch into the on position due to the engagement of the locking member 40 with the hub 34 of the manual.

50 designates generally, the plug which is formed with a cast body 5|, and a suitable cable clamp 52, a shell 53 in which is secured a terminal block 54 provided with a plurality of terminals 55 complemental to the terminals 22 of the receptacle 20. The plug thus described forms per se no part of this invention, and may be of any suitable design or construction.

The shell 53 is provided with a boss 51, and the receptacle housing I8 is provided with a groove 58. The boss 51 and the groove 58 aline the plug with the receptacle so that the proper contacts 55 will coact with the terminals 22. The inner end of the shell 53 is provided with a. notch 60 and with a slot 6| in axial alinement with the notch 60, and so arranged relative to the boss 51 when the plug is inserted into the receptacle housing the notch and slot cooperate with the outer end of the lock member 40 which is notched, or bifurcated at 62 forming projections 63, 64.

When the plug is inserted into the receptacle housing and the contacts 55 engage the terminals 22, the partition engages the projection 63 of the member 40 rotating the member in a counterclockwise direction,at which time the projection 64 of the member 40 extends into the slot 6| as shown in Figures 4 and 5. In this position, the inner end 44 of the member 40 has traveled out of the slot 35 whereupon the manual 33 may be actuated to shift the switch 23 into the on position. The actuation of the manual 33 in the counter-clockwise direction, Figure 2, to shift the switch into on position, shifts the slot 35 out of alinement' with the fiat surface 46 of the end 44 of the lock member 40, as indicated in Figure 5. If an attempt is now made to withdraw the plug from the receptacle, the partition 65 coacts with the projection 64 of the lock member and tends to rotate the lock member in a clockwise direction, Figures 1, 4, and 5. However, due to the fact that the slot 35 is now out of alinement with the surface 43 of the member 40, Figure 5, the rotary movement of the latter will be prevented and it is impossible to withdraw the plug.

By the mechanism above described, I have provided a simple, durable locking mechanism for the combination explosion proof switch housing and plug receptacle which is impossible to get out of order, and foohproof. It will be observed that should the cover l4 be removed from the switch housing and replaced with the manual 33 actuated in the on position, the device could not be used due to the fact that it would be impossible to insert the plug into the receptacle. In such instance, the portion or partition 65 would engage the projection 64 of the lock member 40, and the plug could not be inserted into the receptacle until the operating mechanism had been properly alined.

What I claim is:

l. The combination of an explosion proof switch housing provided with a detachable receptacle housing, a receptacle mounted in said receptacle housing and a plug slidable axially into and out of said receptacle housing into and out of engagement with said receptacle, a switch mounted in the switch housing, a cover detachably secured to the switch housing, a switch actuating member journalled in the cover and having one end extending outwardly through the cover toward the receptacle housing, and being operable to actuate the switch to on and off positions, the receptacle housing being provided with an extension on one side, a latch member rotatably mounted in said extension on an axis extending transversely of the plug and receptacle, one end of said latch member extending into the receptacle housing and being engageable by the plug when inserted in the housing, the outer end of said latch member cooperating with the outer end of the switch actuating member to prevent actuation of the same after the plug has been Withdrawn from the receptacle, and to prevent withdrawal of the plug from the receptacle after the switch actuating mechanism has been actuated into on position.

2. The combination of a switch housing provided with a receptacle housing, a receptacle mounted in the receptacle housing, and a plug slidable into and out of the receptacle housing into and out of engagement with the receptacle,

a switch mounted in the switch housing, a cover detachably secured to the switch housing, a switch actuating member rotatably mounted in the cover and having one end extending outwardly therefrom, the receptacle housing being formed with an arcuate extension abutting the outward end of the switch actuating member, a latch member rotatably mounted in said extension on an axis extending transversely of the plug and receptacle and having one end extending into the receptacle housing and being engageable by the plug, the other end of said latch cooperating with the outward end of the switch actuating mechanism to prevent rotation of the same after the plug has been withdrawn from the receptacle, and to prevent withdrawal of the plug from the receptacle after the actuating member has been rotated into on position.

3. The combination of a switch housing provided with a receptacle housing, a receptacle mounted in the receptacle housing, a plug slidable into and out of said housing into and out of engagement with the receptacle, a. switch mounted in the switch housing, a cover detachably secured to the switch housing, a. rock shaft journalled in said cover and having its inner end coacting with the switch to operate the same into on and off positions, and its outer end extending toward the receptacle housing, the receptacle housing being provided with an arcuate portion extending toward the outer end of the rock shaft and housing the same, a latch member rotatably mounted in said projection upon an axis transverse to the plug and receptacle having its inner end extending into the receptacle housing and being engageable by the plug when the same is inserted in the housing, the outer end of the rock shaft being provided with a slot, and the outer end of the latch member being arranged to move into and out of said slot upon rotation about its axis, the latch member cooperating With the rock shaft to prevent rocking movement thereof after the plug has been withdrawn from the receptacle, and to prevent withdrawal of the plug after the rock shaft has been rocked to actuate the switch in on position.

CARL H. BISSELL.

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