US 506092 A
Description (OCR text may contain errors)
' (No Model.) 2 Sheets-Sheet 1.
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ELHGTRIGAL SWITCH. No. 506.092. Patented Oct. 3, 1893.
Inventor: Ca/rZ 0 GB 5 his ya v %W/M v 2 Sheets-Sheet 2. O. 0. 0. BILLB ELECTRICAL-SW1 No. 506,092. Patented Oct. 3,1893.
Jldarlwys UNITED STATES PATENT ()FFICE.
CARL O. C. BILLBERG, OF PHILADELPHIA, PENNSYLVANIA.
SPECIFICATION forming part of Letters Patent No. 506,092, dated October 3, 1893.
Application filed July 23, 1892- Serial No. 441,033. (No model.)
To all whom it may concern:
Be it known that I, CARL O. O. BILLBERG, a subject of the King of Sweden and Norway, and a resident of Philadelphia,Pennsylvania, have invented an Electrical Switch, of which the following is a specification.
My invention has more particular reference to rheostat switches which are especially applicable for use in connection with electric motors, although certain features of my invention are applicable to other forms of switches.
The main object of my invention is to so construct an electrical switch, as to lessen, as far as possible, the troubles and evil effects arising from the sparking such as occurs in the manipulation of switches as ordinarily constructed, and this without lessening the current capacity of the switch when it is on closed circuit.
In the accompanying drawings, Figure l is a section on the line 1-2, Fig. 2. Fig. 2 is a face view of the switch. Fig. 3 is a view illustrating the spring latch which may be employed to hold the switch lever in position for the closing of the circuit. Fig. 4 is a detached perspective view of the stop plate shown. Fig. 5 is a section on the line 3-4, Fig. 2. Fig. 6 is a section on the line 56, Fig. 2. Fig. 7 is a perspective View of one of of the contact carbons. Fig. 8 is a sectional View, illustrating a modification of my invention; and Fig. 9 is a face view of the switch shown in Fig. 8.
The several features of my invention hereinafter set forth may be applied to various forms and constructions of electrical switches, but in the drawings I have shown it applied to a form of switch in which the contact plates are arranged in a circle and the contact lever A is a transverse bar adapted to turn around a central axis within the ring of contact plates. The several contact plates are arranged on a board B or other suitable base of insulating material, or if it is of conducting material, the contact plates are to be insulated therefrom. The axis or pivot a for the contact lever A is also secured to the same base, and a spring a is provided and so combined with the lever as to tend to turn the latter in a direction contrary to that pointed out by the arrow in Fig. 2.
I have shown the spring a as a spiral spring inclosed with a recess in the lever and coiled around the fixed pivot a, and having one end fastened to the pivot and the other attached to the lever (Fig. 3). As shown in Fig. 2 the lever is in a position with both its contacts resting upon insulating material or insulated parts of the switch, so that the circuit is broken, as will be hereinafter described.
As shown in Figs. 1 and 2, there are two contact rings, one within the other, the inner ring consisting of a segmental metal plate D and a short piece of insulation E separating adjacent ends of the segment which is connected to one terminal 11 of the electrical circuit. The other terminal 10 of the circuit is connected to the plate D of the outer ring which is mainly composed of a series of segmental plates d insulated from each other, as clearly shown in Fig. 2. This insulating material m may consist of mica with plaster of paris or other suitable material. The plates are preferably undercut as shown in Fig. 6, and the number of these plates may be varied in accordance with the varying resistances required where the switch is to be used. These several plates are electrically connected with each other through resistances to permitof throwing on and off the current comparatively gradually instead of instantly as would be the case if these contact plates and resistances were not employed. IVhen the contact lever A is in the position shown in Fig. 2, the contact O rests upon the insulating surface E of the inner ring, while the contact 0 rests upon an insulating or insulated surface of the outer ring.
I provide the switch lever A with carbon contacts to bear upon the contactplates of the rheostat. There are two sets of carbon contacts in the present instance, one contact 0 traveling over the inner ring D, and the other (consisting preferably of two contacts 0) traveling over the outer ring. The contact G is cylindrical in form, and is adapted to an opening in the lever A, a spring 3 being mounted within a cup 8 and so situated as to force the carbon upon the ring D.
I prefer to mount two carbons C in the lever to travel over the outer ring, although one carbon may be used. These carbons are so shaped as to fit over one of the segments cl, being tapered in form, as shown in Fig. 7. These carbons fit in pockets a formed in the lever A and are pressed against the partition plates a by side springs a, and are pressed down upon the outer ring by springs a These springs are secured to the lever A by screws or other fastenings. Thus by this arrangement a good contact is insured, not only between the outer ring and the carbon, but also between the carbon and the lever.
The contact blocks may be'of hard carbon, plumbago, or other equivalent material, but I will simply use the term carbon as applicable to all. By the use of these carbon contacts the injurious ettects of sparking in the movement of the switch levers over the contact plates of therheostat islargely avoided, but in order to still further lessen the wear of these contacts, and of the contact plates, I provide metal contacts y y, (Figs. 1, 2, and 5,) one projecting from the last of the contact plates 61', and the other projecting from the leaving point of the contact plate D, so that the extensions w, :10 of the lever A in breaking the circuit may make contact with these plates 3 y, and the sparking will be produced at theplatesinsteadofatthecarbonoontacts, thus preventing the rapid destruction of the carbon and the contact plates of the rheostat as the plates y,y' can be readily repaired or removed, if necessary with the least amount of cost. A stop X of bent sheet metal, shown in Fig. 4:, is provided to receive the extension at: of the lever A, and hold the latter in the position shown in Fig. 2 against the action of the spiral spring a to keep the circuit normally open. To close the circuit the lever A is turned by hand in the direction of the arrow Z, Fig. 1, gradually cutting on the current through the resistances of the rheostat and tensioning the spring a until the extension w of the lever is received into and engages with the metal contact stop (Z. This metal contact stop d is provided to act in conjunction with the extension 00 of the lever in order that when the circuit is closed there will be less resistance offered to the current than if it had to pass through only the less conductive carbon contacts. A pin ac on this extension 00 engages with a spring latch F pivoted at f, and acted upon by a spring f as shown in Fig. 3. This latch holds the lever in the closed circuit position against the action of the spring a.
\Vhen ever it is desired to open orbreak the circuit again, it will suffice to press back the spring latch F, whereupon the lever A will be released, and the spring a will turn the lever back to the position shown in Fig. 2, and in doing so will cut ofi the current gradually through the resistances.
In Figs. 8 and 9, I have shown a modification of my invention; the device therein shown is intended mainly for small switches, and in this instance only one contact ring is used,one half of the ring comprising the contact D, and the other half of the ring comprising the segments cl. In place of the tapered carbons I have shown cylindrical carbons mounted in spring cups .9, and between the cups and the carbons are springs s which force the carbons down upon the contact plates. In other respects the construction and operation of this device are similar to those already described.
I claim as my invention- 1. An electrical rheostat switch havinga series of contact plates connected through resistances and a metal contact stop, with a switch lever carrying carbon contacts for the rheostat contact plates and having a metal extension to engage with said contact stop to lessen the resistance for the closed circuit, substantially as and forthe purpose described.
2. An electrical rheostat switch having electrical contacts, and a switch lever carrying carbon blocks to bear on said contacts, and having extension pieces with metallic plates at the leaving points of the said contact plates to engage with the said extension pieces in breaking the circuit.
3. The combination in a switch, of the ring composed of a series of segments, a lever centrally pivoted in respect thereto, said lever having pockets with carbon contact blocks adapted to said pockets, a partition separating the pockets, springs for forcing the carbons against the partition, and springs for forcing the carbons down on the ring, substantially as described.
In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.
CARL O. O. BILLBERG.
WILLIAM D. CONNER, HARRY SMITH.