US971843A - Electric switch. - Google Patents

Description

L. W. HOR'I'HTG-u ELECTRIC SWITCH.

APPLICATION FILED D3014, 1909.

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LEVI W. HORTING, OF LANCASTER, PENNSYLVANIA, ASSIGNOR OF ONE-THIRD TO CHARLES E. STAUFIEER AND ONE-THIRD TO B. GRANT STAUFFER, OF LANCASTER,

PENNSYLVANIA.

Specification of Letters Patent.

ELECTRIC SWITCH.

Patented Get. 4., 191%.

Application filed December 14, 1909. Serial No. 582,984.

To all whom it may concern:

Be it known that I, LEVI WV. HORTING, a citizen of the United States, residing at Lancaster, in the county of Lancaster and State of Pennsylvania, have invented certain new and useful Improvements in Electric Switches, of which the following is a specification.

As is well known, when the electric current is broken, an arc is formed at the point of break, which, from various causes not necessary in this connection to mention, may be of considerable intensity and magnitude; and it means are not provided for prevention, very destructive burning may occur. This destructive burning or arcing may be reduced to a practical minimum by breaking the circuit very quickly, and one of the means commonly employed for accomplishing this result is to provide a mechanism which will instantly and positively break the current, and which when once set in motion will perform its duty independent of the operator. Also, not only must the mechanism operate as described, when breaking thecurrent, but it must operate similarly when completing the circuit, otherwise the operator by slow or uncertain movement when closing the switch may cause a sustained destructive arc to appear at the of quick break switches that the present invention relates. As, however, there are various cases where it is necessary to vary the current or c ange its distribution after the circuit has been completed, I have found it desirable'to combine the make and break mechanism with a means for producing such variation or change of distribution, and the objects of the present'invention are,first, to

provide an improved switch whose opening and closing movements are quick and pos1-. tive and independent of the operator after being set in motion, and, second, to provide a switch of the character aforesaid which when closed can be set to various other points necessary for current regulation or distribution.

In the accompanying drawings, which are to be taken as a part of thisspecification: Figure 1 is a plan view of a switch embodying my invention. Fig. 2 is a side elevation, looking at the left hand side of Fig. 1. Fig.

It is to this class make electrical contact with the contact 1 points 0 0 -0 of a variable resistance.

B is a earn, as hereinafterdescribed, moving with lever A and which is or may be aiiixed thereto for that purpose.

C is a separately movable contact lever, pivoted on the common pivot K.

Carried on G between guides D D, is a plunger rod E with its line of motion radial to K. The plunger rod, actuated by a spring F, carries at its inner end a roller G which under force of said spring bears against the cam B. The said cam may be described as presenting two oblique surfaces, 2'. 0., oppositely oblique to the lever C. The plunger rod E is titted in the guides D D with suificient play to allow some wabble but no turning. Turning is or may be prevented by a cross-pin on the rod extending into a longitudinal slot in the lever. The spring F, preferably a coiled spring placed upon the-plunger rod between the guides I) D, may operate against the said cross-pin to drive the roller G against the cam.

M is a stop to limit motion of the lever C in a direction toward the lever A.

P is a post with contact point for coaction with a contact point carried by lever C, which completes the circuit when lever C is thrown against it, and which also seryes as a stop to limit motion of said lever in the opposite direction. Besides the contact P, another stop Q is added to prevent the lever C from moving too far when the contact points P and G wear down.

In the practical construction of the switch, the levers A and C, including the parts respectively carried. by them, and the pivot K, are electrically connected. The pivot.K, the contact po1nts O, O, O O the stop M, the contactand stop I, and the sto Q, are all so arately insulated from eac other. The 0 point 0 and the start ing point 0 are electrically connected to prevent arcing at that point if lever leaves 0 before lever C breaks the clrcult.

The operation'will now be described with reference to the diagrammatic view in F 1g.

'3, wherein for the purpose of illustrating an application of my invention, the switch is shown with proper connections for the speed control of a shunt motor by means of variable resistance in the armature circuit. is shown'connected to one armature terminal. The other armature and field terminals are connected together and to the opposite pole of the electrical circuit from P. The drawing in Fig. 3 being diagrammatic, the plunger rod and spring are not'shown. The lever A, cam B, lever C and roller G are shown in full lines in the off position. The dotted lines represent the positions of these parts in the initial starting position, and the dash-and-dot lines indicate the full running position. A represents the main operating lever int-he initial starting position, and A represents the same in the full on position. B and B are the correspond ing positions of the cam. C denotes the le ver C in the on position. G, G G and G represent successive positions taken by the roller G as the switch is moved from off to full running position and back again to off position.

It will be noted that when the operating lever A is in the off position, shown by full lines, the cam B is in such position that the roller G driving against it exerts a force upon the lever C tending to hold the latter against the stop M, and also exerts a force upon the lever A tending to move it in the opposite direction. The friction of the contact between the lever A and the points 0 O O is or may be great enough to over balance the force exerted by roller G or as shown in Fig. 1 the lever A may be restrained by a strap bearing thereon and holding it by frictionin any position; so thus all the force is exerted on lever C, holding it away from P and keeping the circuit open. When now the lever A (operable manually or mechanically) is moved from the off point 0 to the first on point 0 where it is indicated by the dotted lines at A the oblique surface of the cam B moving with the lever forces the roller up to the peak of the cam, to the position G in: asmuch as the roller is prevented from moving laterally with the lever and cam by the stop M which limits the motion of lever C in that direction.

As previously noted, the plunger carrying the roller G is loosely fitted in its guides, al owing it to wabble.

' roller unstable when at the eak of the cam,

as shown in the position therefore, as soon as the cam moving with the lever A reaches the proper point, the roller instantly This makes the drops over the peak and is forced down the other obliquesurface of the cam to the position shown as G This change of motion exerts a force upon the lever C opposite to the stop M, and as said lever C is unrestrained it is forced against contact P in the position C The circuit is thereby closed, allowing current to pass from P through lever C (in the C position) to K and directly through the motor fields, and from P through levers C and A' (in the C and A positions, contact 0 the resistance coils, contact O and through the armature in series with theresistance coils.

Ifnow the lever A be moved from the A position to the contact point 0, where it is indicated by the dash-and-dot lines as A the cam will move with it and take the po sition B The surface of the cam presented to the roller in the various positions from B to B is so shaped that practically the same angle of obliquity in relation to the line of motion of roller G is retained at any position between B and B Therefore, when the cam is in the position B the roller will have moved to the position G also the roller will exert a force upon lever C tending to hold it in contact with P in any of the running positions, with the cam varying in position from B to B With the operating lever in the position A the switch is in the full-on position,-

with all resistance cut out, and the motor running under full-potential. The operating lever may now be moved at will to any point between 0 and O Without disturbing the contact between lever C (in the C position) and P. If, however, it is desired to open the switch, the operating lever is moved back to the off point 0, carrying the cam B to the position shown in full lines a and forcing the roller up to the position G The relation of the partsis such that when lever C is in the C 'position, resting against P, and the cam takes the B position, its peak is carried past the line of motion of the roller at G*. This again presents the first oblique surface of the cam to the roller, which is forced down to the position shown in full lines at G, carrying the contact lever to position C, breaking the current and placing the switch in the off position.

In order to get as unstable aposition as possible when the roller is on the peak of the cam, I have found it desirable to make the roller of as large a diameter as the partic-' ular design will permit. Also, while I have i radial line of motion of the roller. In this connection, referring to Fig. 1, the cam B may be pivoted on K and secured to lever A by a pin or stud b on the lever loosely fitted in a hole therefor in the cam. A screw may be provided for rigidly affixing the cam to the lever, and upon loosening the screw a half turn or so, to release cam fromthe head of the screw, a slight lateral motion is allowed.

lVhile I have in my description used the butt-on contact, at the point of make and break, it is obvious that any form of contact not offering too great a resistance to the plunger spring may be used. Also, I am aware that minor changes may be made in the arrangement, construction and combination of the parts which will not depart from the nature and principle of my invention and among other things, I do not limit myself to the specific contact maker and breaker comprising two make and break contacts as there may be one or more pairs of quick acting make and break contacts used in this mechanism.

I claim as my invention 1. An electric switch including, in combination with a switch-operating lever, a

' contact make-and-break lever, and means for eifecting quick action of the latter comprising a spring-actuated roller carried thereby and a peaked cam against which the roller bears, said cam being movable by said operating lever and formed to present oblique surfaces on opposite sides of its peak to the roller for throwing the contact make-andbreak lever in opposite directions, the said roller traveling down one oblique surface of said cam to operate said make-and break lever in one direction, and down the other oblique surface to operate it in the opposite direction.

2. An electric switch, comprising an operating lever, a cam unstably mounted on said lever, quick-acting make-and-break contacts, and mechanism operated by said cam to operate said contacts.

3. An electric switch, comprising an operating lever, quick make-and-break contacts, a cam operated by said lever, a roller ada ted to engage said cam, a. support on whlch said roller is mounted for wabbling movement relative thereto, a mechanical connection. between said roller support and said quick make-and-break contacts whereby thelatter are operated by said cam.

4. An electric switch, comprising an operating. lever, a plurality of contacts on which the same moves, a cam mounted on said lever, a roller adapted to engage-said cam, a

lever on which said roller is yieldingly mounted, and quick make-and-break contacts operated by said last-named lever.

5. An electric switch, comprising an operating lever, contacts on which same moves, a quick make-and-break lever, separately insulated limiting stops for same, said limiting stops acting as off and on points of the make-and-break lever, a roller supported on said make-and-break lever, a cam in the plane of said make-and-brea'k lever, and moving centrally with it, oblique surfaces on said cam bearing against said roller, said oblique surfaces so shaped that the same angle is presented to said roller in any position of said roller and said cam within the limits of their motion, substantially as described.

6. An electric switch, comprising a series of contacts, an operating lever movable over and controlling said contacts, quick makeand-break contacts, a lever carrying one of said contacts, a cam mounted on the firstnamed lever, a roller mounted on the second named lever and adapted to travel on said cam, and means to force said roller toward said cam, said cam being so shaped as to permit of a limited movement of the firstnamed lever in either direction without imparting movement to said second leverand during such times acting to place said s ring under compression, and at the end 0 said limited movement, to allow accelerated motion of said second lever under the action of said spring in expanding.

7. An electric switch, comprising a series of contacts, an operating lever movable over and controlling said contacts, quick makeand-break contacts, a lever carrying one of said contacts, a cam unstably mounted on the first named lever, a roller unstably mounted on the second named lever and adapted to travel on said cam, a spring acting to force said roller toward said cam, said cam being so shaped as to permit of a limited movement of thefirst named lever in either direction without imparting movement to said second lever and during such times acting to place said spring under compression, and at the end of said limited movement, to allow accelerated motion of said second lever under the action of said spring in expanding.

In testimony whereof I atfix my signature, in presence of two witnesses.

LEVI W. HORTIN G.

\Vitnesses:

EDNA M. CHRIST, HARRY G. MILLER.

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