US2300222A - Switch - Google Patents

Description

Oct. 27,l 1.942.A w. v. HONEY ASWITCH I 'Fed march -11,I 1941 .3 Shawna-Sheet` 1 F@ 5. .rz ff (EJIllllllllllllllllllll'lllllllhm Inventor: WllllamV l-Iohex l)by .X7/Md.

His Attorney loef. 27, 1942.1

w. v. Hom-:Y

swncn Filed March 11, 1941 s sheets-sheet? Inventor: Wil-Ham V Hong. v b JVM 6J s His Attor'ne'y.

Oct. 27, 1942.

SWITCH 'v v Filed uar'cn 11, 194x 3 Sheets-Sheet 3 Inventor: William Hohe 2 His Attorney Patented Oct. 27, 1942 SWITCH William V. Honey, Fortress Monroe, Va., assigner to General Electric Company, a corporation of New York Application March 11, 1941, Serial No. 382,795

(Cl. 20G-1!) 22 Claims.

My invention relates to electric switches, and although not limited thereto, it has application to a hand-operated motor starting and reversing switch.

An object of my invention is to provide an improved switch which will have long life, be easy to operate, and which will have such construction as to facilitate assembly thereof.

Another object of my invention is to provide an improved switch construction of the abovementioned type which will have a minimum of size for a maximum current carrying capacity of its contacts.

A further object of my invention is to provide a switch structure with an improved contact design so as to minimize bouncing and to provide for a rolling action between the contacts when they are being moved into engagement.

A still further object of my invention is to provide an improved latching mechanism for a switch for holding the actuating mechanism thereof in a predetermined position.

A still further object of my invention is to provide an improved locking mechanism for a switch for controlling the direction of movement of the actuating mechanism thereof.

My invention will -be more fully set forth in the following description referring to the accompanying drawings, and the features of novelty which characterize my invention will be pointed out in the claims annexed to and forming a part of this specication.

In the drawings, Fig. 1 is a front view of a double-pole double-throw switch the cover having been partly broken away, which is provided with an embodiment of my invention; Fig. 2 is a side elevation in partial section of the switch illustrated in Fig. l; Fig. 3 is a top View, with the top part of the casing broken away of the switch illustrated in Figs. l and 2; Fig. 4 is a skeleton perspective view of the current carrying members of the switch illustrated. in Figs. l to 3; Fig. 5 is an enlarged view of one of the pairs of contacts and a portion of the operating mechanism thereof, of the switch illustrated in Figs. 1 to 3, the switch contacts being in open circuit position; Fig. 6 is a View of the pair of contacts illustrated in Fig. 5 in a fully closed position; Fig. '7 is a perspective view of two movf" able contacts and a portion of the operating mechanism thereof, of the switch illustrated in Figs. 1 to 3; Figs. 8. 9 and 10 are enlarged side elevations of the locking and latching mechanism employed in the switch illustrated in Figs. 1 to 55 3, the mechanism being shown in a neutral position, in one or a reverse position, and in a second or a forward position, respectively, and Fig. 11 is a perspective View of the locking mechanism illustrated in Figs. 8, 9, and 10.

The switch illustrated in the drawings is a hand-operated motor starting and reversing switch. However, it is to be understood that the improved features of my switch construction may be employed in any other suitable type of switch. The illustrated switch construction includes a plurality of pairs of relatively movable contacts, and an actuating mechanism movable in one direction for closing two pairs of the contacts which may connect the motor across a suitable source of supply to operate the motor in a forward direction, the operating mechanism being movable in a second direction to close the other two pairs of contacts in order to operate the motor in a reverse direction. The operating mechanism includes a contact supporting arm or cross bar upon each end of which is pivotally mounted one of the relatively movable contacts. A contact tip having an arcuate shaped Contact surface extends from one side of the pivot, and the other end is adapted to provide a stop for the contact. Between the stop and the pivot there is provided a spring means for biasing the stop end of the contact into engagement with the supporting arm. Upon movement 'of the actuating mechanism the supporting arm and contact will bodily move until an initial point of engagement obtains between the relatively movable contacts. Further movement of the actuating mechanism will cause the movable tip to roll on the stationary contact until a iinal position of engagement is obtained, the contact pressure being provided through the spring means. The movable contact is held in this latter position by a latching mechanism which cooperates with the operating means. I also provide a locking mechanism which includes a pair of dogs and a locking plate, which when in one position prevents the operating arrangement from being moved in one direction, or in a direction to reverse the operation of the motor, but allow movement of the operating mechanism to close the contacts to rotate the motor in the forward direction. However, upon movement of the locking mechanism to a second position, by any suitable means, such as a key, the actuating mechanism will be allowed to move into a reverse position and at the same time be prevented from moving into a forward position until the locking mechanism is again returned to a neutral or iirst position.

I may also provide improved busbars with slots in the ends thereof for making connection between a pair of relatively stationary perpendicular connecting posts. Thus, by loosening nuts on the posts, the busbars may be removed from the bolts through the slots thereof.

Referring more particularly to Figs. l, 2, and 3, the switch construction shown includes a box or enclosing casing 2D, a removable cover 2|, and a removable dish shape container or oil tank 22, which may be lled with oil if it is desired to have the switch contacts operate in a fluid insulating medium. Thetank 22 is tightly held in a U-shape flange 23 of the enclosing casing in any suitable manner, such as by means of a plurality of bolts and wing nuts 24. A conduit box 25 is provided which may be bolted to the casing 20 through a plurality of bolts 25. The conduit box 25 may in turn be bolted to any suitable support, such as a wall, which will in turn support the entire switch construction. An aperture 21 is provided through which lines or conduits may pass for connecting my improved switch construction with any suitable electric device, such as a dynamoelec tric machine. The conduit box 25 is provided with an insulating plate 28 and any suitable number of busbar studs. Since this switch construction is to be employed as a double-pole double-throw switch, four studs 29, 30, 3|, and 32 are provided. Studs 3| and 32 may be connected to a suitable source of power and 29 and 30 to a suitable device, such as a motor. The studs 29, 3U, 3|, and 32 also are connected to busbars 33, 34, 35, and 35, respectively. The opposite ends of these busbars are adapted to make electrical connection with four contact studs 31, 38, 39 and 40 respectively, which are in turn connected to my improved contact structure which will be described below. Since the busbar studs and contact studs, which are connected together by busbars, are perpendicular to each other, I provide the ends of each of the busbars with U-shaped slots so that the busbars may be conveniently removed by merely loosening the locknuts on each of the studs which are adapted to hold the busbars tightly on the studs. It may also be seen that by removing the two busbars i which are connected to the source of power the switch may be isolated therefrom in a simple and a convenient manner.

In order to provide a relatively stationary support for the contact structure, a base or supporti..

ing plate 4| of insulating material is placed within the enclosing casing and is stationarily mounted thereon through inwardly extending ribs 42, bolts 43 being provided for tightly securing the base 4| to the ribs. Attached to the base 4|, I may provide any suitable number oi stationary contact studs. Since this switch is employed with a double-pole double-throw switch, four stationary contact posts are provided. rIhese include the studs 31 and 33 and studs 44 and 45. These four contact posts 31, 38, 44, and 45 have relatively stationary contacts 46, 41, 48, and 49, respectively, mounted thereon in any suitable manner, such as by bolts 5i) which extend into cooperating threaded holes in the studs. Adapted to cooperate with these relatively stationary contacts, I provide relatively movable contacts 5|, 52, 53, and 54. Thus, there are provided four pairs of relatively movable cooperating contacts. Contacts 5| and 53 are each connected to the stud through a pigtail 55, and relatively movable contacts 52 and 54 are each connected to the stud 39 through a pigtail 55. These connections may be made in any suitable manner, and in the illustrated construction the two similar pigtails each have their mid-points connected to the studs and their ends connected to the contacts through bolts 51, see Fig. '1. Reversing busbars 58 and 59 are connected between studs 31 and and 38 and 44, respectively. The connection between the studs and bars may be made in any suitable manner, suoli as by bolts G9.

The electrical connections may be traced in the skeleton view illustrated in Fig. fi. Assuming that the studs 3| and 32 are connected to a suitable source of supply and that the studs 29 and 35 are connected to a motor. the circuit may be traced from the stud 3| through the busbar 35 to the center stud 33. Let us iurther assume that the Contact operating mechanisin, which will be described below, has been so operated that the motor is to be run in a forward direction. Thus, contacts 49 and 54, and 4B and 53 are respectively in circuit closing position. The center stud 39 is, therefore, connected through the pigtail 55 to contact 54 which contacts the stationary contact 49. This contact is in turn connected through the busbar 58 to the stud 31 which is in turn connected through the busbar 33 to the outgoing stud 29. The other circuit may be similarly traced from the stud 32, busbar 36, stud liil, pigtail 55, contacts 53, 48, busbar 53. stud 33, busbar 34 to the stud 30. It may be seen that when the contact operating mechanism is moved so that contacts 46, 5|, and 41, 52 are moved to circuit closing positions that the current will be reversed through the motor.

The operating mechanism for the movable contacts includes a plurality of contact supporting arms or cross bars 6 Since a relatively movable contact may be pivotally mounted at each end of the supporting arms only two need be provided in order to support four movable contacts.

However, it is to be understood that any other suitable number of contact supporting arms may be provided, depending upon the number of pairs of contacts which the switch need employ, and, if desired, only one movable contact need be mounted on each supporting arm. The movable contacts may be movably mounted on their supporting arms in any suitable manner, and in the illustrated embodiment of my invention I provide knife edge pivots 62 at each of the ends of the arms. Since each of the movable contacts are similarly mounted only the mountings of one will be described, such as that of contact 54. Referring more particularly to Figs. 5, 6, and 7 it will be seen that a V-shape indentation 63 is provided in the lower side of the contact in order to cooperate with the knife edge pivot 62. The contact is provided with a suitable arcuate shape contact tip surface 64 which is adapted to make rolling contact with the surface of the cooperating stationary contact. The contact end having the tip 64 extends on one side of the pivot while the opposite end of the contact is provided with a stop portion 65 which is adapted to overlie a cooperating portion 56 of the Contact supporting plate. The part of the arm 4between the pivot and the portion 6G is undercut at 61, so that the contact will not touch the arm between these points. Operatively connected to the contact supporting arm and the contact, and between the stop 65 and the pivot 63, I provide a suitable biasing arrangement which includes a spring 68 which is compressed between a portion of a sur- -face 69 on the opposite side of the conta-ct supporting arm from the pivot 62 and a dish shape member 16 which is in turn supported by a spring rod 1|. Aligned apertures 12 and 13 are provided in the contact and the contact supporting plate, respectively, and a T-shape end 14 of the spring supporting rod 1| spans the aperture 12 while the opposite end 15 of the spring supporting rod supports the dish shape member 10. It will be seen, therefore, that the movable -contact 54 is biased towards the contact supporting arm 6| by the spring means 68. The other movable contacts are similarly mounted. These contacts are easily removable by removing the screws 51 and pushing up on the spring 68 and rotating the rod 1|, 90 degrees so as to allow the end 14 to drop through the apertures 12 and 13.

In order to support the contact supporting arm or cross bar, there is provided a shaft 16, which may be covered by any suitable type of insulating material 11, the shaft being rotatably mounted at its ends in bearings 18, one being shown in Fig. 1. The bearings 1B are in turn supported through a bearing bracket 19 from the lower side of the base plate 4|. Suitable bolts 88 connect the bearing 18 to one end of the bracket while suitable bolts 8| connect the opposite end 'of the bracket to the lower surface of the plate 4|. The contact supporting arm 6| is mounted on the shaft 16 in any suitable manner, such as by providing a plate member 82 below the shaft and by tightly securing the plate 82 to the opposite side of the shaft from the contact supporting arm 6| by any suitable number of bolts 83 which extend from the plate 82 into cooperating holes in the Contact supporting arm 6|. It may be seen, therefore, that the contact supporting arm is pivotally mounted at its mid-point on an axis which is perpendicular to its longitudinal axis. Each of the contact supporting arms 6| may be similarly mounted on the shaft 16.

Another part of the contact actuating mechlanism includes a contact positioning or rocker arm 84, see Fig. 1 or Figs. 8, 9, and 10, which has one end tightly secured to the shaft 16, in any suitable manner, such as by a pin 85. The opposite end of the contact positioning arm is provided with a pin 86 which extends from one face thereof. The pin 86 is in turn adapted to be moved or operated by a contact operating arm 81 which has a slot 88, see Figs. 8, 9 and 10, which is adapted to receive the pin 86. The operating arm 81 is vrotatably mounted in the enclosing c-asing 29 through a shaft 89 which extends through a suitable hole or is accommodated by a suitable bearing supported by the enclosing casing 26. The operating arm 81 is also provided with an extension 99 which is adapted to coopate with my improved locking mechanism, which will be described hereinafter. The outside end of the shaft 89 is provided with any suitable operating arrangement, such as a handle 9| so that the switch may be manually operated. It is to be understood that the shaft may be automatically operated, if desired.

It will be seen, therefore, that when the handle as viewed in Fig. 1 is pushed away from you, or as viewed in Fig. 2 is rotated clockwise, the contact positioning or rocker arm 84 as viewed in Figs. 5 and 6 will be caused to rotate around the shaft 16 in a counterclockwise direction. Movement of a sufcient amount will cause the conlli tacts 54 and 49 to move from the position as illustrated in Fig. 5 to the fully closed position illustrated in Fig. 6. When the operating handle is moved in the opposite direction the switch parts will move from the neutral position as shown in Fig. 5 to a reverse position or with the contacts 5|, 46, and 52, 41 in contact.

In order to provide an arrangement for latching the operating mechanism in a neutral, or in -a forward, or in a reverse position, I provide a latching mechanism which includes a latching -arm 92 which is pivotally mounted on a bracket 93 which is in turn supported by the plate 4|. The latching arm 92 is provided with a roller -94 which is adapted to cooperate with any one of three notches 95, 96, and 91 on the contact positioning arm 84, since the latching plate is biased towards the contact positioning arm through a spring 98. Therefore, by means of this latching mechanism the contact mechanism will also be held in a stable manner in a neutral, or in a forward, or reverse position, the neutral 'position being shown in Figs. 5 and 8, the forward position in Figs. 6 and 10, and the reverse position in Fig. 9.

It will, therefore, be seen that with the contact construction as described above that a maximum of wipe and wear allowance will be obtained. Referring again to Fig. 5, contacts 54 and 49 are adapted to make initial engagement at any suitable .point such as the points marked a and b. Furthermore, by suitably proportioning the curve of the arcuate shape tip 64 and the position of the pivot point 62 with respect to the center of rotation of the shaft 16 and the tip, the contacts upon further movement after the points a and b touch, may be made to roll and have substantially no slide therebetween. Thus, after the contacts have touched at the points a and b further movement of the actuating mechanism will cause relative movement between the contact 54 and the contact supporting arm 6| around the pivot points 62 and 63, against the force of the biasing means 68. This movement will continue until the contacts 54 and 49 have reached the position as illustrated in Fig. 6, or until points c and d are in engagement, at which time the roller 54 of the latching mechanism will have dropped into the slot 91 to securely hold the contacts in this position, until the roll 94 is forced out of the slot 91 against the force of the biasing spring 98 by the operator striking a blow on the operating arm 92. In order to minimize the possibility of bouncing as the contacts touch when moving to a closed position, the center of gravity of the contact 54 is at any suitable point toward the stop 65 or to the left of the pivot point 62. Switch structure including a relatively stationary contact, a relatively movable contact, and a contact member resiliently connected to a movable arm, the contact member being pivotally connected to the arm between the center of gravity of the contact member and the relatively movable contact which is carried by the member so as to prevent bouncing during closing of the contacts is described and claimed in an application S. N. 420,107, Stimson, led November 22, 1941, and assigned to the same assignee as this present invention.

In order to provide a contact structure which will have a minimum of resistance during normal running conditions and to minimize the possibility of welding during making and breaking, the contact structure 54, 49 is provided with silver inserts at the points c and d which are so situated that they will be tightly pushed together at the moment that the roll 94 of the latching mechanism drops into the slot 9i. The remainder of the contact tip 54 and the cooperating surface of the static-nary Contact 49 may be made of any suitable contact material, such as that described and claimed in Patent 2,178,598 to Ziclzrick, which is also assigned to the same assignee as this present invention. In the arrangement illustrated only the forward contacts 53, t8, and 54, 49 are provided with this silver insert construction. However, it is to be understood that all the contacts may be so constructed, if desired. All the contacts, however, are mounted so as to produce the wiping action and minimise bouncing. It is also to be noted that the contact pressure when the contacts are in their fully closed position, as illustrated in Fig. 6, is determined by the biasing spring 68. This force may, therefore, be varied by changing the characteristics of the spring.

In order to prevent any unintentional closing of the contacts 5|, 46 and 52, 41, or when my improved switch structure is employed as a starting and reversing switch of a dynamo-electric machine, in order to prevent unintentional reversing of the motor, I provide an improved locking mechanism which is illustrated in Figs. 8 to l1. This locking mechanism includes a pair of dogs 99 and |00 which are pivotally mounted on the casing 29 through pins |9| and W2, rcspecfi tively. The dogs 99 and |09 are biased in one direction by springs ID3 and |94, respectively. In order to control the position of the dogs 99 and |00 I provide a locking plate |35 which is pivotally mounted in the casing 2B through a pivot pin |96. The dog 99 is provided with a stop surface |07 which is adapted to cooperate, when in the position as illustrated in Fig. 8, with a cooperating surface |t 8 of the extension 9i) of the operating arm 87. Thus, when the dog 99 is in the position as illustrated in Fig. 8 the operating arm will be prevented from moving in a counterclockwise direct-ion, or the operating arm will be prevented from moving to a second position or to a reverse position, which position is illustrated in Fig. 9. The dog 99, however, is operatively connected to the locking plate |95 through the slot |09 in the locking plate and a pin IG on the dog. The locking plate and dog 99 may be moved from the position illustrated in Fig. 8 to that illustrated in 9, so that the contacts may be closed to reverse the motor, in any suitable manner. In the arrangement illustrated in the drawings a suitable key arrangement is provided having an L-shaped portion which is attached to a shaft i2 and a suitable handle ||3. An aperture H4 is provided in the casing Zi) and a slot ||5 is provided in the locking plate |95 so that when the key is inserted in the aperture M and rotated from the position illustrated in Fig. 8 to the position illustrated in Fig. 9 the locking plate |05 will be rotated around its pivot |96 and through the pin and slot connection |09, |||l the dog 99 will be moved out of the path of movement of the Contact operating arm. Suitable stops H6, |l`| and IIB may be provided for preventing movement of the locking plate and the key beyond predetermined positions. The dog |00 is provided with a pin H9 which cooperates with a shoulder |23 on the side of the locking plate opposite from that in which the slot |69 is placed. When the locking plate m5 is in the position as illustrated in Fig. 8 the dog |30 will be held out of the range of movement of the end of the operating arm El' so that the operating mechanism may be freely moved from neutral into forward position. However, when the locking mechanism is moved so that the actuating mechanism may be moved into reverse position the dog |99 due to the spring bias |04 will move so that the stop surface |21 is provided so that the actuating mechanism may not be moved into a forward position but may only be moved to a neutral position. lIhe spring |93 is made stronger than the spring H34 so that when the key is removed the locking plate |95 may not be accidently moved or jarred into the position as illustrated in Fig. 9 but will remain in the position as illustrated in Fig. 8, since it will be forced against the stop H5. It will be noted that when the key is inserted and rotated to the position shown in Fig. 9, it cannot be removed until it is returned to the neutral position as shown in Fig. 8. It is to be understood that if it is desired, only one dog need be provided so as to prevent the actuating mechanism from being moved in one direction but which will not prevent it from moving in the opposite direction. Thus, the dog 99 or the dog |99 could be dispensed with in some installations.

In view of the foregoing, it will be seen that I have provided an improved switch construction which includes a contact assembly for providing a rolling action so that the contacts may make and break at one point of contact and run at a second position. The movable contact is movably mounted in an improved manner so as to minimize the possibility of bouncing. I also provide an improved latching mechanism for securely holding the contacts in a neutral, or in a first, or a second position. An improved locking mechanism is also provided for preventing movement of the actuating mechanism in one direction when it is in one position, and when in a second position preventing movement of the actuating mechanism in a second direction.

I have described my invention as applied to a double-pole double-throw starting and reversing motor switch. However, it is to be understood that any other suitable number of stationary and movable contacts may be provided, and that the switch construction may be connected in the line connecting any other suitable electric device with a source of power or another device.

Although I have shown and described particular embodiments of my invention, I do not desire to be limited to the particular embodiments described, and I intend in the appended claims to cover all modifications which do not depart from the spirit and scope of my invention.

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

l. In a switch, a first pair of relatively movable contacts, a second pair of relatively movable contacts, means movable from a neutral position to a first position for actuating said rst pair of contacts and movable to a second position for actuating said second pair of contacts, latching means cooperable with said actuating means for holding said actuating means in its neutral or iirst or second positions in order to hold said contacts in a corresponding position, and locking means cooperable with said actuating means and movable from a rst to a second position, said locking means when in its '.Virst position allowing said actuating means to move from its neutral position to its rst position but preventing movement to its second position, said locking means when in its second position allowing movement of said actuating means from said neutral to its second position but preventing movement to its first position.

2. In a switch, a plurality of pairs of relatively movable contacts, means movable from a neutral to a first or to a second position for actuating a first or a second of said pairs of contacts respectively, latching means cooperable with said actuating means for holding said first or said second pair of contacts in a closed position upon actuation by said actuating means, and locking means cooperable with said actuating means and movable from a first to a'second position, said locking means when in its first position preventing movement of said actuating means to its second position, said locking means when in its second position preventing movement of said actuating means to its first position.

3. In a switch, a plurality of pairs of relatively movable contacts, means including a positioning arm movable from a neutral to a first or to a second position for actuating'a first or a second of said pairs of contacts respectively, a latching arm biased towards said positioning arm and cooperable therewith for holding said positioning arm in said neutral or first or second positions in order to hold said pairs of contacts in corresponding positions, and locking means cooperable with said actuating means and movable from a first to a second position, said locking means when in its first position preventing movement of said actuating means to its second position, said locking means when in its second position preventing movement of said actuating means to its first position.

4. In a switch, a plurality of relatively stationary contacts, a plurality of relatively movable contacts cooperable therewith, a contact supporting arm, means for pivotally mounting said relatively movable contacts on said supporting arm, actuating meansl including said supporting arm movable from a neutral to a rst or to a second position for actuating a first or a second of said relatively movable contacts respectively, latching means cooperable with said actuating means for holding said one or another of said movable contacts in a closed position upon actuation by said actuating means, and locking means cooperable with said actuating means and movable from a rst to a second position, said locking means when in its first position preventing movement of said actuating means to its second position, said locking means when in its second position preventing movement of said actuating means to its first position.

5. In a switch, a plurality of relatively stationary contacts, a plurality of relatively movable contacts cooperable therewith, a contact supporting arm, means for pivotally mounting said relatively movable contacts on said supporting arm, a positioning arm, actuating means including said supporting arm and said positioning arm movable from a neutral to a first or to a second position for actuating a first or a second of said relatively movable contacts respectively into engagement with its cooperating stationary contact, a latching arm biased towards said positioning arm and cooperable therewith for holding said positioning arm in the neutral or first or second positions in order to hold said actuated contacts in engagement, and locking means cooperable with said actuating means and movable from a first to a second position, said locking means when in its first position preventing movement of said actuating means to its second position, said locking second of said pairs of contacts respectively,

vlocking means including a rotatably mounted means when in its second position preventing movement of said actuating means to its first position.

6. In a switch, a plurality of pairs of relatively movable contacts, means movable in a first or a second direction for actuating a nrst or a second of said pairs of contacts respectively, latching means cooperable with said actuating means for holding said first or said second pair of said contacts in a closed position upon actuation by said actuating means, and locking means cooperable vvith said actuating means for preventing movement thereof in one direction when in one position and preventing movement of said actuating means in a second direction when in ay second position.

7. In a switch, a plurality of relatively stationary contacts, a plurality of relatively movable contacts cooperable therewith, a contact supporting arm having knife edge pivots upon which said relatively movable contacts are mounted, spring means for biasing said relatively movable contacts tov/'ard said supporting arm, actuating means including said supporting arm movable from a neutral to a first or to a second position for actuating a first or a second of said relatively movable contacts respectively into engagement with its cooperating stationary Contact, said relatively movable contacts upon actuation by said actuating means into engagement with its cooperating stationary contact being movable about said knife pivot so that it will roll from an initial contact position with its cooperable stationary contact to a final closed position, latching means for holding said relatively movable contact in said actuated position, and locking means cooperable with said actuating means and when in one position preventing movement of said actuating means to its second position and when in a second position preventing movement of said actuating means to its first position.

8. In a switch, a plurality of pairs of relatively movable contacts, means including a contact operating arm movable from a neutral to a first or to a second position for actuating a rst or a latching means cooperable with said actuating means for holding said actuating means in its neutral or first or second position in order to hold said contacts in a corresponding position, a

locking plate and two rotatably mounted dogs cooperable therewith, spring means biasing said dogs into engagement with said plate, said lock- .I ing means being movable from a first to a second position, one of said dogs when said locking means is in its first position cooperable with said operating arm to prevent movement of said actuating means to its second position, the other of said dogs when said locking means is in its sec- 'ond position cooperable with said operating arm to prevent movement of said actuating means to its first position.

9. In a switch, a plurality of pairs of relatively movable contacts, means including a contact yoperating arm movable from a neutral to a first or to a second position for actuating a first or a second of said pairs of contacts respectively, a locking means including a rotatably mounted locking-plate and two rotatably mounted dogs cooperable therewith, spring means biasing said dogs into engagement with said plate, said locking means being movable from a first to a second position, one of said dogs when said locking means is in its first position cooperable with said operating arm to prevent movement of said actuating arm to its second position, the other of said dogs when said locking means is in its second position cooperable with said operating arm to prevent movement ci said actuating means to its rst position.

10. In a switch, a plurality of relatively stationary contacts, a plurality of relatively movable contacts cooperable therewith, a contact supporting arm having knife edge pivots upon which said relatively movable contacts are mounted, spring means for biasing said relatively movable contacts toward said supporting arm, a contact operating arm, actuating means including said supporting arm and said op rating arm movable from a neutral to a first or to a second position for actuating a nrst or a second of said relatively movable contacts respectively into engagement with its cooperating stationary contact, said relatively movable contacts upon actuation by said actuating means into engagement with its cooperating stationary contact being movable about its knife edge pivot so that said Contact will roll from an initial engagement position with its cooperable stationary contact to a final engagement position, a locking means including a rotatably mounted locking plate and two rotatably mounted dogs cooperable therewith, spring means biasing said dogs into engagement with said plate, said locking means being movable from a nrst to a second position, one of said dogs when said locking arm means is in its first position cooperable with said operating arm to prevent movement of said actuating means to its second position, the other of said dogs when said locking means is in its second position cooperable with said operating arm to prevent movement of said actuating means to its first position.

11. In a switch, a relatively stationary contact, a relatively movable contact, a contact supporting arm having a pivot upon which said relatively movable contact is mounted, said relatively movable contact having a tip with a curved surface cooperable with said stationary contact on one side of said pivot, spring means on the other side of said pivot for biasing said relatively movable contact toward said supporting arm, a rotatable shaft. means for mounting said supporting arm on said shaft, a contact positioning arm connected to said shaft, an operating arm operatively connected to said positioning arm so that upon movement thereof said Contact supporting arm will be bodily rotated with said shaft, said last-mentioned movement causing relative movement between said pivot and said stationary contact to move to said movable contact into engagement with said stationary contact, continued movement of said supporting arm causing relative movement between said relatively movable ccntact and supporting arm around said pivot against the force of said biasing means, said relative movement between said relatively movable contact and supporting arm causing rolling movement between said relatively movable and stationary contacts from a point of initial engagement to a point of iinal engagement.

l2. In a switch, a relatively stationary contact, a relatively movable contact having a tip with a curved surface, said curved surface having a point of initial engagement with said stationary contact and another point of final engagement upon actuation of said movable contact toward said stationary contact, a contact supporting arm, means for pivotally mounting said movable contact on said supporting arm, said tip being on one side of said pivot, said contact having a stop cooperable with said arm on the other side of said pivot, spring means operatively connected to said relatively movable contact and said arm between said pivot and said stop for biasing said stop against said arm, means for moving said arm and pivot to cause said relatively movable contact to move therewith until initial engagement is made between said tip and said stationary contact, continuation of movement of said arm causing said contact stop to move away from said arm and movement of said relatively movable contact relative to said arm about said pivot against the force of said biasing means in order to cause rolling of said tip on said stationary contact until the position of nnal engagement obtains.

13. In a switch, a relatively stationary contact, a contact supporting arm, a relatively movable contact pivotally mounted on said arm and having a tip with a curved surface on one side of said pivot, said curved surface and said stationary contact having a point of initial engagement and another point of final engagement upon actuation of said movable contact toward said stationary contact, said relatively movable contact having an end remote from said tip extending on the opposite side of the pivot, said extension being of such size relative to the contact tip that the center of gravity of said relatively movable contact is between said end and said pivot, spring means operatively connected to said relatively movable contact and said arm and between said end and the pivot for biasing said end in engagement with said arm, means for moving said arm and pivot to cause said relatively movable contact to move therewith until initial engagement is made between said tip and said stationary contact, continuation of movement of said arm causing said contact end to move away from said arm and movement of said relatively movable contact relative to said arm about said pivot against the force oi said biasing means in order to cause rolling of said tip on said stationary contact until the position of nal engagement obtains.

14. In a switch, a relatively stationary contact, a contact supporting arm having a pivot, a relatively movable contact pivotally mounted on said arm and having a tip with a curved surface on one side of said pivot, said curved surface and said stationary contact having a point of initial engagement and another' point of nal engagement upon actuation of said movable contact toward said stationary contact, said contact having an end remote from said tip extending on the opposite side of said pivot, said extension being of such size relative to' the contact tip that th'e center of gravity of said relatively movable contact is between said end and said pivot, spring means operatively connected to said contact and said arm and between said end and the pivot for biasing said end into engagement with said arm, means for rotatably mounting said contact supporting arm about an axis perpendicular to its longitudinal axis, means for rotating said arm about its rotational axis to cause said contact to move therewith until initial engagement is made between said tip and said stationary contact, continuation of movement of said arm causing said contact end to move away from said arm and movement of said relatively movable contact relative to said arm about said pivot against the force of said biasing means in order to cause rolling of' said tip on said stationary contact until the position of final engagement obtains.

15. In a, switch, a relatively stationary contact, a contact supporting arm, a relatively movable Contact pivotally mounted on said arm and having a tip with a curved surface on one side of said pivot, said curved surface and said stationary contact having a point of initial engagement and another point of nal engagement upon actuation of said movable contact toward said stationary contact, said contact having an end remote from said tip extending on the opposite side of the pivot, said extension being of such size relative to the contact tip that the center of gravity of said relatively movable contact is between said end and said pivot, rod means having one end connected to said contact at a point between said end and said pivot and extending through substantially aligned apertures in said movable contact and said arm, spring means compressed between said arm and the other end of said rod means for biasing said end of said contact into engagement with said arm, means for moving said arm and pivot to cause said contact to move therewith until initial engagement is made between said tip and said stationary contact, continuation of movement of said arm causing said contact end to move away from said arm and movement of said relatively movable contact relative to said arm about said pivot against the force of said biasing means in order to cause rolling of said tip on said stationary contact until the position of iinal engagement obtains.

i6. In a switch, a plurality of pairs of relatively movable contacts, actuating means including an operating arm movable in a first or a second direction for actuating a first or a second of said pairs oic contacts respectively, a locking means including a rotatably mounted locking plate and two rotatably mounted dogs, said locking plate having a slot, one of said dogs having a pin adapted to nt into said slot and a stop portion, spring means biasing said one of said dogs so that said stop portion is in the path of movement of said operating arm so as to prevent movement thereof in a first direction, means for moving said locking plate to a seco-nd position so as to move said dog out of the path of movement of said operating arm so that said arm may move in said first direction, said second dog being movable into the path of movement of said arm when said plate has been moved to said second position so as to prevent movement of said arm in said second direction.

17. In a switch having relatively movable contacts, means for actuating said contacts and movable in a first or in a second direction, locking means including a dog biased to a position to prevent movement lof said actuating means in said first direction, a locking plate having a slot, said dog having a pin adapted to l'it into said slot, said locking plate being movable so as to cause movement of said dog to a second position through said pin and siot connection, said dog When in said second position being out of the path of movement of said actuating means so that said actuating means is movable in said first direction.

18. In a switch having relatively movable contacts, means for actuating said contacts and movable in a rst or in a second direction, locking means including a pair of movably mounted spaced dogs, one of said dogs being biased to a position to prevent movement of said actuating means in said first direction, said other of said dogs being biased to a position to prevent movement of said actuating means in said second direction, means cooperable with said dogs and when in one position adapted to retain said second dog out of the path of movement of said actuating means, said last-mentioned means being adapted to be moved to a second position to retain said first dog out of the path of movement of said actuating means and to allow said second dog to move into the path of movement to prevent movement of said actuating means in said second direction.

19. In a switch having relatively movable contacts, means including a Contact positioning arm and an operating arm for actuating said contacts, an oncle-sing casing, a supporting plate, means for mounting said supporting plate in said enclosing casing, means for movably mounting said positioning arm on said supporting plate, means including a shaft extending through an aperture in said casing for pivotally mounting said operating arm within said casing, an operating handle attached to the end of said shaft extending through said aperture, and a pin and slot connection between said operating arm and positioning arm so that the latter is movable to actuate said contacts upon movement of the former and so that said supporting member may be removed from said casing upon disassembly thereof from said casing without removing said positioning arm from said shaft.

20. In a switch, an insulating base, a contact, a Contact stud having one end connected to said contact and the other end extending from said base, a line stud adapted to be connected to a line and extending in a direction perpendicular to said contact stud, a removable busbar for connecting said contact stud to said line stud, said studs having locknuts threaded thereon for tightly holding said busbars to said studs, and U- shaped slots in said busbar in the portions thereof which make contact with said studs so that loosening of said nuts from said busbars will allow said busbars to be removed from said studs through said U-shaped slots.

21. In a switch, a rst pair of relatively movable contacts, a second pair of relatively movable contacts, means movable from the neutral position to a iirst position for actuating said rst pair of contacts and movable to a second position for actuating said second pair of contacts, and locking means cooperable with said actuating means and movable from a rst to a second position, said locking means when in its rst position allowing said actuating means to move from its neutral position to its first position but preventing movement to its second position, said locking means when in its second position allowing movement of said actuating means from said neutral to said second position but preventing movement to its rst position.

22. In a switch, a plurality of pairs of relatively movable contacts, means movable from a neutral to a first or to a second position for actuating a rst or a second oi said pairs of contacts respectively, locking means cooperable with said actuating means and movable from a iirst to a second position, said locking means when in its first position preventing movement of said actuating means to its second position, removable key means insertable in the switch for moving said locking mechanism to said second position for allowing said actuating means to move to its second position, and means for preventing the removal of said key means with said locking means in said second position.

WILLIAM V. HONEY.

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