US1671615A - Electric switch - Google Patents

Description

May 29,1928.

v 1,671,615 H. A. SPAHR ELECTRIC SWITCH Filed Nov.24, 1926 2 Sheets-Sheet 1 %1/am qffa'a r May 29, 1928. 1,671,615

, H. A. SPAHR ELECTRI C SWITCH Filed Nov.24, 1926 2 $7?ts-$heet 2 Patented May 29, 1928.

UNITED STATES PATENT OFFICE.

ELECTRIC swrrcn.

Application filed November 24, 1926. Serial No. 150,553.

This invention relates toelectric switches.

Objects of this invention are to provide a novel form of electric switch which is adapted for actuating by means of a cam, such for example, as a cam carried by the car of an elevator and in which the operating mechanism is completely housed with only the pro- 'ecting cam follower located outside of the ox, the springs, of this type being protected against mechanical injury and from dust by means of the housing.

Further objects are to provide a novel form of a switch in which the plunger or rod may be readily displaced by the cam, such rod having both a sliding and a rocking motion to thus permit the utmost ease in operation and reduce the wear to a minimum.

Further objects are to provide an electric switch of the above type in. which means are provided for limiting the throw or stroke of the rod and in which a novel form of restoring or repositioning mechanism is provided for returning the switch to its neutral or normal position.

Further objects are to provide a simple, practical, durable switch and one in which 8. wi ing contact is secured so .that the switc is in effect self-cleaned.

In elevator work, it is occasionally happens that the car overuns and with the usual type of limit switch, it is necessary to operate the winding mechanism manually to reposition the car and to restore the electric circuit. 'However, this invention has for its further ob'ect the provision of a novel form of switch m which the switch may be again closed after it has been opened, by a very small movement of the car in a reverse direction, so that the complete travel of the cam away from the switch is not required and thus the labor of repositioning the .car is reduced to a minimum.

Embodiments of the invention are shown .in the accompanying drawings in which Figure 1 is a sectional view through the switchsuch view corresponding to a section on the line 1-1' of Figure 2; "Figure 2 is a horizontal sectional view on the'line 2-2 of Figure 1; Figure 3 is a sectional view on the line of Figure 1;

contacts, and other parts- Figure 4 is asectional view on the line H of Figure 1;

Figure 5 is a sectional view corresponding to Figure 1 showing a modified form;

Figure 6 is a sectional view partly broken away on the line 6-6 of Figure 5;

. Figure 7 is a view of a further form of switch such view being partly in section;

Figure 8 is a sectional view on the line 88 of Figure 7 Figure 9 is a view showing the relation of the cam and switch.

Referring to the drawings, particularly the first form illustrated imFigures 1 to 4:, it will be seen that the switch comprises a housing 1 which is preferably formed of metal and is of box-like contour. The body portion of this housing may conveniently be open at the top, such opening being closed by a removeable cover 2. The front wall of the housing is provided with an aperture, preferably rectangular, as indicated by the reference character 3. Through this aperture, a reciprocatory and rocking rod or plunger 4 passes. This plunger is forked at its outer end and carries a cam follower which may' take the form of a roller, as indicated by the reference character 5. This roller is adapted to be actuated by means of a cam hereinafter described. The rod 4 carries a cross head, indicated generally by the reference character 6. This cross head'is located interiorly of the front wall of the casing, as shown in Figure 1, and is provided with an upper and a lower bearin I, portion 7, such portions contacting with tile inner face of the frontwall. The parts are'urged into their normal position,

-as shown in full lines in Figure 1, by meansof springs, such for example, as those indicated by the reference character 8 in Figure 2. These springs may be attached to the front wall as shown in this figure, or may be attached to other portions ofthe casing, if desired, one of the other possible modes of attachment being subse uently described.

The cross head. 6 may take various shapes provided it is equipped with the bearing surfaces or extensive, upper and lower portions, as described above. For example, as shown in Figures 1, 2, and may be substantially T-shape.- Preferably, a guiding member such as the triangular 4, this cross head in any suitable manner,

plate 9 is secured transversely of the bar 4 as illustrated particularly in Figure 2. This plate loosely contacts with the side walls of the casing and prevents any possibility of lateral dislacement of theinner free end of the rod. l lowever, the extensive bearing faces under normal conditions produce this result as well as the plate 9. In the event that the cam becomes excessively worn on one side, so that it presents a tilted face to the roller, the tendency would be to rock the rod 4 horizontally as well as vertically. This rocking although resisted by the extensive bearing portions 7 is completely stopped by the plate 9. This plate 9 may contact with upper and lower lugs or stops 10 formed on the inner face of the casing to thus limit the throw of the switch.

The end of the rod is preferably turneddown to provide a bearing pin 11. Upon this pin a roller is mounted such roller consisting of an insulating central portion 12 surrounded by a metal shell 13. The roller is adapted to travel between the upper and lower pair of contacts 14, as shown in Figure 3. These contacts are preferably carried by U-shaped spring arms 15 which have their central portions secured to the casing. If desired, the contact 14 may have integrally formed rearwardly extending threaded pins 16 which are locked in place by means of nuts 17 additional nuts being employed to secure the conductors to the contacts, such conductors and additional nuts being omitted for the sake of clearness.

When the cam is travelling downwardly,

' it deflects the roller and bar into the dotted line position shown in Figure 1. It is to be noted that the bar not only travels inwardly but also rocks at the same time and thus conforms more nearly to the direction of motion naturally imparted to the roller by the downwardly travelling cam. Of course, the cam in its upward travel defleets the-,bar in a reverse manner. This rocking ofrthe bar causes the roller to move between'one or the other of the pairs of contact faces and to complete the circuit. The roller, it will be noted, has its metal sheath insulated from the remaining p0rtion of the apparatus and further it will be noted that the roller is given a slight turn by contacting more or less with one or the other of the contact members. This causes a wiping action to occur and presents a clean face for contact purposes under all conditions.

Referring to Figures 5 and 6 which show a further form of the invention, it will'be seen that the same general idea is carried out in this form. A casing 18 is provided with a removable cover 19 and a plunger or rod 20 is employed in a manner similar to that previously described/ This plunger may be spring urged towards neutral position as previously described, or the springs 21 may be attached to other portions of the device, such as shown in Figure 5, for instance, the springs acting to urge'the cross head 22 into contact with the front face of 7 the box. However, it will be noted that the front face is provided with an aperture 23 which may be circular, if desired, and which does not function to guidethe rod 20. Instead, the rod is provided with a slot 24 which cooperates with a transverse bar 25. This provides the guiding for the rod and permits its reciprocatory and rocking mo tion. The usual roller 5 may be employed for the outer end of the rod.

It is to be noted that the guiding pin 25 may have its ends flattened, as indlcated at 26 in Figure 6. These ends maybe passed through slots 27 formed in the front face of the box and then clamped in place. provides a simple means of attaching the pin or guiding bar 25.

The roller 28 is constructed in a manner similar to that previously described; However, the'stop or limiting means for arresting the roller at opposite ends of its stroke consists of a disc or large washer 29 carried adjacent the inner free end of the rod 20. This disc or washer contacts with the top or the bottom of the box and thus limits the rocking motion of the rod and holds the roller out of contact with the metal parts of the box.

In the form shown same general idea is employed. A reciproin Figures 7 and 8, the

This

catory and rocking rod 30 carries the roller upright gui'dingstrip 33. If desired, the.

same type of roller and contacts may be employed. However, as illustrated in these figures, an insulating double wedge shape member 34 is employed to separate the normally closed contacts 35 (See Figure 8). This insulating member moves upwardly between the contacts and separates them and interposes itself between the active faces of the contacts, thus extinguishing any are that might be instantaneously formed. Further, to aid in-this operation the opposedfaces of the contacts are preferably bevelled, as indicated at 36.. This aids in the entrance of the wedge shape ends of the separating member 34.

It is to be separating insulating member may be substituted for the roller in any of the forms illustrated or that the roller and its corresponding contacts may replace this separating insulating member in the last described form.

Referring to F igure 9, it will be seen that the relation of the cam and switch is illustrated. The cam 37 may be carried by the car of the elevator and may be elongated and provided with tapered ends, as shown.

Assuming that the cam. is moving down, it will force the roller 5 inwardly and downwardly. This is an easier movement for the movable parts of the switch to execute than a direct inward reciprocatory mot-ion and, consequently, less stressand less wear are occasioned. Further, a reverse direction of travel of the cam operates the mechanism in the reverse manner causing the roller to move upwardly and inwardly.

It occasionally happens in elevator practice that thelimit switch is opened by excessive travel of the car, and when this limit switch is employed to cut off the entire current from the motor, it is apparent that the car must be restored to its normal position by manual means. This is-a slow and laborious operation as it requires the car to be moved a distance equal to .the distance of travel of the cam from its initial point of en agement with the switch.

owever, with this invention, such extensive travel of the car is not required in restoring the switch. It is apparent from considering Figure 9 that only a very slight upward motion ofthe car is needed to restore this switch in the full travel of the cam. In other words, a slight upward motion of the cam 37 will cause the roller to rock upwardly into normal position as the springs and the arrangement of parts of the switch aid in this restoring movement.

It is to be distinctly understood that other shapes of cross heads and other shapes of contact members or se arating members and guiding members can he employed and that the springs may 'be attached to any desired part of the apparatus so long asthey exert a yielding restoring pressure upon the rocking and reciprocatory bar.

It is to be understood that if desired any of the forms of switch shown may be made as a single switch by merely omitting one set of contacts and repositioning the stops.

It is to be understood further that although the switch has been described as carried by an elevator car and the cams as stationary, it-is clear that the cam may be carried by the car and a mounted at each of the landings.

Although the invention has been described in considerable detail, such description is intended as illustrative rather than limiting as the invention maybe variously embodied and the scope of such invention is to be determined as claimed.

I claim:

'1. An electric switch comprising an enclosing casing having stationary contacts therein, a reciprocatory and rocking rod passing through the front of the casing and having means at its inner free end cooperatseparate switch.

ing with the contacts, a pair of springs associated with the rod and with the casing and tending to hold the rod in neutral position irrespective of its direction of displacement, said springs being located on opposite sides of said rod a cross head carried by said rod and bearing against the front inner face of the casing, and means carried by the outer end of the rod and adapted for actuation by a cam. 2. An electric switch comprising an enclosing casing having stationary contacts therein, a reciprocatory and rocking rod passing through the front of the casing and having means at its inner free end cooperating with the contacts, a pair of springs associated with the rod and with the casing and tending to hold the rod in neutral position irrespective of'its direction of displacement, a cross head carried b said rod and bearing against the front inner face rigidly carried by the rod and having spaced upper and lower feet providing extensive bearing surfaces contacting with the inner face of the front wall of the casing, anda pair of springs positioned within said casing and secured at their front ends thereto, said springs bein located on opposite sides of said rod an having their rear ends attached thereto.

4. An electric switch comprisin a casing, a rod projecting through the ront wall thereof and provided with a cam follower at its outer end, means carried by the inner end of the rod for engaging contacts, a pair of stationary contacts mounted within the casing and adapted to be engaged by said means when said rod is rocked, a crosshead rigidly carried by the rod and having spaced upper and lower feet providing extensive bearing surfaces contacting with the inner face of the front wall of the casing, and a pairof springs positioned within said casing and'secured at their front ends thereto, said springs being located on opposite sides of said rod and having their rear ends attached thereto, and means for limiting the rocking motion of said rod, said means controlling the inner free end of said rod.

5. An electric switch comprising a casing having a front wall provided with an aperture, a rod slidably and pivotally passing through said aperture and having a cam said rod is moved inwardly and rocked, a

cross head carried by said rod and having a pair of elongated bearing faces contacting and resiliwith the inner face of the casing,

faces into 10 cut means urging said bearing contact with said casing.

In testimony that I claim the foregoing I have hereunto set my hand at Milwaukee in the county of Milwaukee and State of Wisconsin.

HOWARD A. SPAHR.

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