US2186818A - Electric switch - Google Patents

Description

Jan. 9, 1940. 54 BROWN 2,186,818

ELECTRIC SWITCH Filed Nov. 11, 19:57

Inventor: Geor e R. Brown,

Hus Attorney 7 Patented Jan. 9, 1940 UNITED STATES PATENT OFFICE ELECTRIC SWITCH New York Application November 11, 1937, Serial No. 173,954

10 Claims.

This invention relates to electric switches of the type employing liquid contact circuit closers which are rotated to control the flow of current.

It is an object of the invention to provide an 3 improved construction and arrangement of switches of this type in which the circuit closer may be reversed in position to form a switch which is either normally open or normally closed.

Referring to the drawing Fig. l is an illus-' l tration of the switch applied to a door jamb; Fig. 2 is a plan view of the switch with the housing broken away; Fig. 3 is a cross-sectional view through the switch structure; Fig. 4 is an exploded view of the clamping means for the 5 connecting cable; Fig. 5 is an exploded view of the switch elements; and Figs. 6 to 9, inclusive, illustrate the liquid circuit contact closer and the various positions taken by the circuit closer during operation of the switch as a normally m open or a normally closed switch.

The switch comprises a cylindrical housing III which may be lined with an insulating shell II in order to insulate the switch elements from the housing and the surrounding structure. The 25 housing is made in-cylindrical form for ease in mounting the switch. With an ordinary rectangular switch housing it is necessary to mortise the mounting board; with a cylindrical-housing, however, it is only necessary to bore a hole N- and insertithe housing in order to mount the switch in operative position thereby effecting a considerable saving in labor costs. Within the housing III a base l2 of insulatingmaterial is provided having a rearwardly extending projec-.

36 tion 13 which serves to separate the terminal angle strips l4 and 'I5. In order to connect the terminal strips to the conducting wires, terminal screws I6 and I! are provided. The terminal wires may comprise part of a BX cable 40 having conductors l8 and I8 and a protective armor l8". In order to clamp the armor, to the casing and thus prevent the connections between the conductors and terminals from becoming loosened, opposed clamping members 19 and 20 45 are placed about the armor immediately adjacent the housing 10. The clamping plates have prongs or projections 2| and 22 extending within slots 23 and 24 formed upon opposite sides of the opening 25 placed in the end of the housing.

60 The clamping prongs grip the end of the housing as the clamping members are tightened about the armor by means of the screws 26 and 21 threaded through openings l9 and 20' formed in the clamping members. In order to hold a liquid circuit closer in operative position, two contact members 28 and 29 are mounted upon the base 12 and are secured to the terminal strips l4 and I6, respectively, by means of rivets 36 and 3|. The contact member 28 is U-shaped, one end of the U being inserted in a recess 32 formed 5 in the base l2 where it is secured to the terminal l5 by the rivet 3|. An insulating plate 33 overlies the recess to protect the end of the contact member and is secured to the base by the rivet 30 which connects the contact arm 29 to the terminal strip I4, the contact arm overlying the insulating plate. The contact member 29 and insulating plate 33 are set into a recess-34 formed v upon the base, as best shown by Fig. 5. The contact members 28.and 29 are formed with projections 35 and 36 which extend toward each other to engage and hold the liquid circuit close 31.

The liquid circuit closer 31 comprises a pair of cup-shaped- metal terminals 38 and 39 which are separated by an insulating diaphragm 40 which may be for-med of refractory material such as a ceramic material. In order to seal the edges of the terminals a glass bead 4| is formed between the metal terminals 38 and 33 and seals the junctions between these terminals and the insulating diaphragm 40. Within the space enclosed by the terminals is a quantity of mercury 42 which forms the conductive medium between the two terminals. In the manufacture of the 80 circuit closer the space enclosed by the terminals is evacuated and filled with hydrogen gas at a pressure of one or more atmospheres, so that the current-carrying capacity of the circuit closer is increased. The insulating diaphragm 40 is provided with an opening 43 shown by Figs. 6 to 9, inclusive, which is submerged in the mercury when the circuit closer is in current-carrying position and which is moved to a position above the mercury when the circuit closer is in open position. The terminals 38 and 39 of the circuit breaker are provided with depressions 44 and 44' which are placed at the same angular position on the circumferences of the terminals. For the purpose of mounting the circuit closer on the contact members, the terminals are provided with depressions 45 and 46 which are engaged by the projections 35 and 36 formed on the contact members. In this manner the circuit closer is mounted for free pivotal movement about the contact members which at the same time make contact with the terminal members of the circuit closer so that the merciu'y will close the circuit through the contact niembers as the opening in the diaphragm is inserted in the mercury. I

In order to operate the circuit closer, a cylinupon the projection 41' a rectangular plunger 52 is provided with keys 53 which ride in the grooves 50 and formed in the cup member 49. The plunger is guided and supported upon bearing surfaces 54 formed in'a sleeve 55 which is mounted in recesses 56 formed on the front of the housing member. The guiding surfaces 54 take the form of a rectangular opening formed in the sleeve 55 and are adapted to prevent the rectangular plunger 52 from rotating as the keys 53 engage the grooves in the cup-shaped member, as well as providing a support for the plunger. The plunger is held in an extended position by means of a spring 5'! which engages the rear of the cup member 49 at one end and bears against a washer 58 at the other end. An antifriction ball 59 is locked between the washer 58 and the end 60 of the plunger to provide for free relative movement between an operating means and the plunger. The keys 53 engage the inner edges 54 of the bearing surfaces 54 and prevent the plunger from being expelled from the sleeve under the action of the spring 51. To hold the switch elements in assembled relationship, the sleeve 55 is provided with rearwardly extending arms 6| and 62 which coact with the beveled faces 63 and 64 formed on the base member and which are provided at their ends with locking prongs 65 and 66 which engage the recesses 61 and 68 formed in the base member I2. The assembled switch structure is clamped to the housing by a face plate 69 which retains the sleeve 55 in position in the recesses 56 by means of the locking screw 10. In order to mount the housing on a supporting wall or panel, grooves H are provided in the extension 12 formed on the housing member In. These grooves are adapted to be engaged by supporting screws (not shown).

In assembled relationship the spring acts to hold the plunger in extended position. Depression of the plunger will cause rotation of the cylinder and circuit closer and compression of the spring. As the spring is compressed it will exert a force on the rear of the cylinder causing the projection 41' to press the contact 28 toward the contact 29 thereby insuring a good electrical contact between the circuit closer and the contact members as the switch is operated.

One use of the switch is as a door switch to control an electric circuit in response to the opening and closing of a door. This use is illustrated by Fig. 1, the switch being mounted in the door jamb J by means of the extensions 12 formed on the housing. The door D is provided with an abutment plate 13 for cooperation with the plunger 52. Opening and closing of the door will cause the plunger 52 to be extended and depressed, alternately, and thereby cause rotation of the liquid circuit closer. The circuit closer is keyed to the cylinder 41 by means of the key 48' and one of the depressions 44 and 44'.

By properly positioning the depressions 44 and 44' and the opening 3 formed in the diaphragm. it is possible to reverse the liquid circuit closer to provide a switch which is either normally open or normally closed.

Referring to Fig. 6 it will be seen that the depression 44 is formed on a linesubstantially 60 degrees to the left of the vertical, while the opening 43 is formed on a line substantially 60 degrees to the right of the vertical. The pitch of the spiral grooves 50 and 5| is so designed that depression of the plunger will rotate the cylinder 4! and thereby the circuit closer through an angle of 120 degrees. If now the circuit closer is inserted in the switch to take the position shown by Fig. 6 and the plunger is in extended position, the switch will be normally open. It will be apparent that upon depression of the plunger the circuit closer will move clockwise in the direction shown by the arrow through an angle of 120 degrees to a final position illustrated by Fig. '7. In this position the switch is closed with the opening 43 immersed in the mercury and the plunger is depressed completely within the cup 49. In the event that it is desired to have a switch which is normally closed the circuit closer is removed from between the contacts and is reversed to a position illustrated by Fig. 8, so that the depression 44' on the opposite terminal will be engaged by the key 48 when the switch is in normal position with the plunger extended. It will be apparent that if the switch is now operated by depression of the plunger the circuit closer will be rotated clockwise in the directionshown by the arrow through an angle of 120, so that the circuit closer will take the position shown by Fig. 9 with the opening in the diaphragm removed from contact with the mercury and the switch in open position. It will thus be apparent that by providing the circuit closer with two depressions 44 and 44' and by placing the diaphragm opening at an angle of 120 from the depressions that a switch is devised which may be operated as a normally open or a normally closed switch by reversing the position of the circuit closer.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In an electric switch, a liquid contact circuit closer, contact means pivotally supporting said circuit closer, a cylinder keyed to said circuit closer, a cup having a spiral groove connected to said cylinder and a plunger having means cooperating with said grooves whereby reciprocation of said plunger will cause rotation of said circuit closer.

2. In an electric switch, a liquid circuit closer haying terminal portions, one of said terminal portions having a depression formed therein, a rotatable member having a key engaging said depression, opposed contact means mounting said circuit closer for rotation, an element having a spiral groove engaging said member, and a plunger having means engaging said groove whereby reciprocation of said plunger causes rotation of said circuit closer.

3., In an electric switch, a liquid circuit closer, opposed contacts mounting said circuit closer for rotation about its axis to open or close a circuit. a cylindrical member keyed to said circuit closer, a cup having a spiral groove inserted in said member, a plunger having a projection inserted in said groove. and a spring between said cup and plunger.

4. In an electric switch, a liquid circuit closer, opposed contact members, said contact members having means pivotally mounting said circuit closer for rotation to open or close a circuit, a cylindrical member keyed to said circuit closer, means having a spiral groove inserted in said cylindrical member, and a plunger having a key coacting with said groove whereby said circuit closer may be rotated upon reciprocation of said plunger.

5. In an electric switch, a liquid circuit closer having terminal portions, angularly aligned depressions formed in said terminals, contact means mounting said circuit closer for rotation to open or close a circuit, rotatable means having a key engaging one of said depressions, a reciprocating plunger, means to translate reciprocation of said plunger into rotation of said means to operate said circuit closer, said circuit closer being reversible in said contacts with said key engaging the other of said depressions whereby said switch may be operated as a normally open or anormally closed switch.

6. In an electric switch, a liquid circuit closer operable upon rotation to open or close a circuit, contacts pivotally mounting said circuit closer, a rotatable member connected to said circuit closer, an element having a spiral groove secured to said member and a plunger having means cooperating with said groove whereby longitudinal movement of said plunger causes rotation of said circuit closer, said circuit closer being connected to said member when said plunger is in normal position so that the circuit through said contacts and circuit closer is in open position, said circuit closer being adapted to be reversed in position so that when saidplunger is in normal position the circuit through said contacts and circuit closer is in closed position.

7. In an electric switch, an elongated housing, a base positioned within said housing, a. liquid circuit closer, opposed contacts supported by said base and mounting said circuit closer for rotation about its axis to open or close a circuit, a

rotatable member mounted within said housing in axial alinement with said circuit closer and being operatively connected therewith, a reciprocable element mounted in said housing and movable in a direction parallel to the axis of said circuit closer and having a portion extending beyond the confines of said housing, and means interconnecting said element and member whereby movement of said element operates said circuit closer.

8. In an electric switch, a liquid circuit closer having terminal portions, angularly alined connecting means formed on said terminals, contact means mounting said circuit closer for rotation to open or close a circuit, rotatable means engaging one of said connecting means, a reciprocating element, means to translate reciprocation of said element into rotation of said rotatable means to operate said circuit closer, said circuit closer be- 6, ing reversible in said contacts with said rotatable means engaging the other of said connecting means whereby said switch may be operated as a normally open or a normally closed switch.

9. In an electric switch,a liquid circuit con- J troller, opposed contacts mounting said circuit controller for rotation about its axis to open or close a circuit, means provided with a spiral groove connected to said circuit controller for rotation therewith and a plunger having means I engaging said groove whereby reciprocation of said plunger causes rotation of said first-mentioned means and said circuit controller.

10. In an electric switch, a liquid circuit controller, opposed contacts mounting said circuit controller for rotation about its axis to open or close a circuit, an element keyed to said circuit controller and being provided with a spiral groove and a plunger havinga projection engaging said groove whereby reciprocation of said plunger causes rotation of said circuit controller.

GEORGE R. BROWN.

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