US1671269A - Electric switch - Google Patents

Description

May 29, 1928.

C. W. BASSETT ELECTRIC SWITCH Filed Oct. 31, 1923 INVENTOR BY M M 1 ATTORNEYS Patented May 29, 1928.

I UNITED STATES PATENT OFFICE.

- CYRUS W. BASSETT, F MAPLEWOOD, NEW JERSEY, ASSIGNOB .IIO ELE VATOR SUP- PLIES COMPANY, INC., A CORPORATION OF NEW JERSEY.

ELECTRIC swircn.

Application filed October 31, 1923. Serial No. 671,841.

The present invention relates to electric switches, and more particularly to a switch adapted to be employed where a rapid and reliable making and breaking of a circuit is desired.

In switches heretofore employed for the purpose of automatically making and breakmg circuits as in elevator operating circuits, for instance, wherein the operating circuit is to be broken when the elevator door is opened, considerable annoyance has been experienced due to relatively poor operation of the switches when the parts become worn, and to the necessity of frequently replacing worn parts in the switches.

It is the primary object of the present invention to provide a switch which shall operate extremely rapidly to make or break a circuit without appreciable sparking, and

to maintain an efficient contact between the parts when the switch is closed whereby the wear and consequently the cost of maintenance of the switches is appreciably diminished.

In the accompanying drawings showing a preferred embodiment of the invention;

Fig. 1 is a view in elevation of the switch mounted so as to turn on and with a with a portion of the cover removed, the

switch being shown in closed position;

Fig. 2 is a cross-sectional view of the switch through line 2-2 of Fig. 1;

Fig. 3 is a cross-sectional view of the switch taken on the line 33 of Fig. 1;

Fig. 4 is a view similar to Fig. 1 showing the switch in open circuit position; and

Fig. 5 is a perspective view of the switch shown in operative position as applied to the toggle levers of an elevator door.

Referring in detail to the drawings, 1 is a casing to which suitable lugs 3, 5, having openings therein, are attached, by means of which the casing may be readily mounted in position. I

Within the casing are-contact blocks or brushes 2, 4 which are mounted upon a block 14 of insulating material such as bakelite, the brushes being held in place by means of metal plates 10, 12, preferably of brass. The plates 10, 12 are fastened to the insulating block 14 by means ofv screws or other suitable means. The contact blocks 2, 4 may be made of any suitable conducting material, but I'prefer to make the blocks of copper graphite and in a form larger at the base than at the top so as to be readily held 111 position by meansof plates havin an opening of a proper size to rigidly hol the said blocks. The plates 10, 12 may have extending portions or terminals 9, 11 to which leads 6, 8, which pass into the casing prefero0 ably through openings 18, 20, may be readily attached. In order to avoid coming into contact with or to interfere with the operation of the switch, one lead, as the lead 6, for example, which is attached to the terminal at the lower end of the casing, is passed through a groove or passage 16 in the block 14. I

e In the lower portion of the casing is a lever or cam member 22 which is preferably ivot 24, which passes through one end 0 the lever. The pivot 24 is mounted in the covers of the casing, and is attached, externally to the casing, to an arm 25, which is 76 operated by a mechanism to which it is attached. If the switch is used in an elevator circuit, for example, the arm 25'may be attached to a connecting arm 27 which in turn i *connected to the toggle lever 29, asshown 80 if; Fig. 5 of the drawings, by the movements ofwhich the switch is opened and closed.

In order to operate the switch, to bring the conducting bar 38 in and out of contact with the blocks 2, 4, the bar 38 is flexibly mounted upon a second lever 30, which is operatively connected to the lever 22. The lever 30, which is preferably made of two similar or corresponding parts or sides, is mounted within the casing upon a pivot 32, and is connected to the lever 22 in any suitable manner to. cause operation thereof. I preferably mount the lever 22 between the two sides of the lever 30 as shown in Fig. 2 and provide grooves 28 in each side of the 96 lever 30 with which a pin 26 in the lever 22 cooperates, and by means of which the lever 30 is directly operated. Between the parts or sides of the lever 30, and near the upper end thereof, I employ ,ablock or bar 33 of 100 suitable insulating material, preferably of bakelite, in which are parallel openings or holes 34, 36, the function of which will be hereinafter explained. The openings are preferably flared toward the ends or have cross sections in the form of arcs, as shown in Fig. 1 of the drawings, by means of which the bar 38 may adjust itself at any angle,

within certain limits, with the lever 30. A conducting member 38 of suitable conducting material, such as brass or copper, and

adapted to bridge the space between the con-- tactblocks, is employed to make and break the circuit through the terminals by bringing the conducting member in and out of ed upon the block 37 or insulated portion of the conducting member are two threaded bolts or screws 40, 42 which are adapted to pass through openings 34, 36 in the block 33, and to slide therein. The movement of the lever on the bolts 40, 42 is limited by means of nuts 44, 46 which are attached to the outer portion of the screws. The nuts may be ad'usted in position upon the screws and held y means of lock nuts 45, 47 as shown in the drawings, whereby contact may be made between the upper surface of the lever and the nuts at any predetermined position of the lever with respect to the conducting member, and thereby control the maki g and breaking of the circuit by con trolling the position of the point of contact of the conducting member 38. Between the blocks 33 and 37 is a spring 48 which is preferably maintained in compression by means of which the conducting member may be' held in contact with the brushes offirmly contact blocks 2, 4 when a lever is moved so as to attain contact. The spring is preferably held in place by inserting it into openings or holes in the blocks 33 and 37. The openings 34, 36 are of such a size with respect to the bolts and in such a position with respect to the lever that when the lever is brought into closed position of the switch the conducting member 38 will be moved longitudinally with respect to the brushes 2, 4 so as to attain a wiping contact between the brushes and the conducting member, whereby'a clean surfaceanda substantially perfect contact may be maintained. Inother words,

when the switch isclosed by means of theswinging of the lever 30 through an are around the pivot 32 the conducting member is brought into contact with the brushes or contact blocks 2, 4 and thereafter as the lever 30 is forced inwardly by the movement of the lever 22 against the force of the spr1ng'48, the vertical component of the are through which the outer end of the lever moves or the component parallel to the brushes is taken up by the movement of the conducting member along the upper surface of the brushes or blocks.

I In order to permit this movement without having the conducting member raise at one end, the diameter of the openings in the lever through which the bolts pass is made slightly larger than that of the bolts, and are flared at the ends in order to provide the necessary clearance.

When the lever 30 is moved away from the conducting member 38 the spring 48 holds the conducting member 38 against the brushes 2, 4'until the upper portion of the lever strikes on the nuts 44, 46 and rapidly pulls the conducting member 38 away from the brushes. The slots 28 in the sides of the lever 30, which by the movement of the pin 26 therein controls the movement of the lever, are so designed that as the lever moves toward the nuts 44, 46, the pin 26 will be in contact with the right hand side of the slot, due to the force of the compression spring 48. At the time the conducting member 38 is ready to leave the brushes 2, 4, or when the upper portion of the lever 30 has reached I the- nuts 44, 46 on the bolts-40, 42, the pin ,26 moves to the other or left hand side of the slot 28 and by its cam action in the slot draws the lever 30 and conducting member 38 rapidly away from the terminals or brushes 2, 4. The movement of the conducting member away from the brushes maybe controlled, as desired, by the form of the slot 28 in the lever 30, but it is particularly desirable that at the moment the conduct-- with the pivot 24 as its center, whereby substantially no movement of the lever 30 takes place after the pin 26 has reached the circular part of the slot. ;It is apparent, therefore, that when the switch is applied to the toggle levers of an elevator door, after the conducting member is drawn away from the brushes at the first part of the movement of the toggle levers, there is no further movement of the lever 30 and conducting member 38 during the remainder of the movement of the toggle levers until the same portion of the door stroke is attained in the closing movement thereof.

While the switch has been described as being adapted particularly for opening and closing an elevator operating circuit, it is to be understood that the switch may be used in any circuit in which the opening and closing thereof is to be made dependent upon the operation of a lever or other device, and that the switch may be used in any place or for any purpose for which it is adapted. It is to be understood also that various modifications in the device may be made without departing from the spirit or scope of the invention as defined in the claims.

Having thus described the invention, what is claimed as new is:

1. In an electric switch, a casing, a pair of terminals, conducting blocks connected to said terminals, means for insulating said conducting blocks from each other andfrom said casing, a conducting member adapted to bridge said conducting blocks, means for moving said member into and out of contact with said blocks, the said means com-- prising a lever pivoted at one side of said blocks, a slot in said lever, a threaded bolt operatively attached to said conducting means and passing through the slot in said lever, a clearance between said slot and said bolt to permit seating of said conducting meanson said terminals in all contacting positions thereof, spring means between said conducting member and said lever whereby said conducting member may be held in contact with said blocks during movement of said lever with respect to said blocks, said bolt cooperating with said lever to move said conducting member longitudinally with respect to said blocks after contact therewith to attain wiping contact between said member and said blocks.

2. In an electric switch, a casing, contact blocks within said casing, insulating means between said casing and said blocks, means for attaching leads to said blocks, a conducting member adapted to make and break a circuit through said blocks, a lever pivoted at one end and connected to said conducting member, a slot in said lever, a second lever having a pin at one end and pivoted at the other end thereof, said pin operating in said slot to move said slotted lever and said conducting member toward and away from said conducting blocks, a pair of threaded bolts connected to said conducting member and passing through openings in said lever, said openings being of sufiicient size to allow play between said lever and said bolts, nuts on said bolts adapted to be placed thereon so as to attain simpltaneous contact with said lever when said conducting member is to be withdrawn out of contact with said conducting blocks, and a spring between said lever and said conducting member adapted to hold said conducting member against said conducting blocks when said lever is moved into position to attain closing of the circuit through said blocks and said conducting member. 7

3. In an electric switch, a current conducting member and means for positively moving said current conducting member into and out of circuit closing position, comprising a pivoted lever, a slotted guide in said lever, a pin movable along Said guide, a rocker arm for angularly moving said pin in said guide, and ,means for relatively disposing said pin and guide so that a uniform rate of angular movement of said rocker arm causes a variable rate of angular movement of said lever and conducting memher, said means comprising a plurality of cam faces of diiferent contours in said guide.

4. In an electric switch, a terminal, a selfadjusting conducting member having a flat continuous face adapted to contact with said terminal, means for positively moving said conducting member into and out of engagement with said terminal, comprising a lever pivoted at one side of said terminal, a slotted cam-shaped guide in said lever, a pin movable along said guide, a rocker arm for angularly moving said pin in said guide, means for relatively disposing said pin and camshaped guide so that a uniform rate of angular movement of said pin causes a variable rate of angular movement of said lever and conducting member, whereby most rapid movement of said conducting member occurs in proximity to said terminals, means for holding said conducting member in pressure contact with said terminal when in engagement therewith, and means for producing transverse sliding contact between said terminal and said conducting member when said lever is operated to move said conducting member into and out of engagement with said terminal. I

5. In an electric switch, a terminal, a selfadjusting conducting member having a fiat continuous face adapted to contact with said terminal, means for positively moving said conducting member into and out of engagement with said terminal, comprising a lever pivoted at one side of said terminal, a slotted cam-shaped guide in said lever, a pin movable along said guide. a rocker arm for angularly moving said pin in said guide. means for relatively disposing said pin and cam-shaped guide so that a uniform rate of angular movement of said pin causes a variable rate of angular movement of said lever and conducting member, whereby most rapid movement of said conducting member occurs in prox mity to said terminal, means for positively withdrawing said conducting means out of contact with said terminal, and means for causing a limited movement of said withdrawing means relatively to said conducting means to attain motion of said withdrawing means before withdrawing said conducting means away from said terminal.

Signed at Maplewood, N. J this 23d day of October, 1923.

CYRUS W. BASSETT.

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