US1768461A - Switch-operating mechanism - Google Patents

Description

June, 24, 1930. c. F.CARPENTER swn'c'n OPERATING MECHANISI Filed April '13. 1928* W Inventor-z Charles F'Ca #065 His Attorneg. I

Patented June 24, 19301 UNITED ST TES PATENT orrlca CHABLES I. CARPENTER, OI AIDY, NEW YORK, ASSIGNOR TO GENERAL ELEC- TRIO comm, A OOBP OBATIOH 01' NEW YORK SWITCH-OPERATING IECKANISH Application fled April 13,

My invention relates to electric switches and more particularly to operating mechanism there or. I

Although it obviously has other applicaul in 6 tions, my invention is particularly use connection with controlling apparatus for electric motors.

A great majority of certain types" of electric motors as for instance, squirrel cage in- 1 duction motors, are started by connecting them to a reduced primary volta during the starting interval, the redu primary voltage beingobtained by the use of transformer methods or by the use of primary resistances. After-a certain time interval has elapsed to allow the motorto accelerate, the motor is directly connected to the full line voltage. Starters comprising-switches having two sets of contacts are ordinarily provided, first, to connect the motor to the remf ing handle or lever and it is very desirable in as the contacts touch, and therefore ny'invention in one of its aspects contemplates the provision of a switchin mechanism, the contacts of which are positively forced into a mechanical and electrical engagement without the necessity of employing excessive actuating forces.

Controllers provided with two such sets of contacts are generally operated by a startstoppin the motor that when the handle is moved m the running position at which full voltage is applied to the motorto the neutral position it does not or is not swung past the neutral position to the starting posi tion at which low voltage is applied to "the motor. Another aspect of my invention is the provision of a starting mechanism of the type utilizing two sets of contacts and an operating lever therefor'in which the lever is me. semi 10. 20am.

preventing rapid movement" of the actuating mechanism from the running to the starting position.

For a more complete understanding of my,

invention reference should be had to the accompanying drawing in which Figure 1 is a perspective view of the switching mechanism with portions broken awa to illustrate certain structural details; igure 2 is a front elevation ofthe switching mechanism showing it in its starting position; Figure 3 is a front elevation of the switching mechanism showing it in its running position; and F1gure 4 is a detail of a portion of the latchm mechanism.

ferring to the drawing, I have shown my invention in one form as applied to a motor controller in which two sets of contacts are employed, one set for connecting the motor to a low voltage source and one set for connecting the motor to a high voltage source. As shown, a suitable framework 10 is provided for supporting a platform or plate 11 to which the elementsthat make up the switching mechanism are attached. Two

sets of stationary contacts 12 and 13 are pro I vided, the contacts 12 leading to a source of low voltage, and the contacts 13 leading to a source of higher voltage. Two sets of movable contacts 12" and 13 are provided for engaging the contacts 12 and 13 respectively w ereby the circuits may be comletedfrom the voltage sources of the motor. it will be understood that the numberof contacts in each set depends upon the type of motor to be controlled and upon the method employed to obtain the reduced voltage. For instance, in controlling a three p ase induction motor where the reduced voltage is secured by the use of a transformer, five pairs 0 starting contacts 12 and 12" are providedfor connecting the moloo tor to the low voltage source and three pairs of running contacts 13 and 13 are provided for connecting the motor to the high voltage source. A contact supporting member or switch arm 14 is provided, the switch arm having two sets of spaced arms 15 and 16 to which the move is contacts 12 and 13 are respectively pivoted. The lower portion of the contact carrying member 14 is provided with rigid cross member 17 between the ends of which and the movable contacts 12 and are inserted springs 18, this construction permitting the contacts to be swung about their pivots relative to the switch arm 14 as they move into engagement with their cooperating stationary co tacts.

An insulated shaft 20 suitably supported at each end from the plate 11, as by means of a bearing member 21, is provided for rotatabiy supporting the switch arm 14. A fever member 23 is rigidly secured to the shaft 20 and mechanism cooperating with the lever 23 is provided for biasing the shaft 20 to its neutrai position, that is, the position in which both sets of contacts are held out of engagement. As shown two levers 24 and 25 are pivoted to the bearing bracket 21, these members being disposed on opposite sides of a crank arm 23 projecting from the lower end of the lever 23. A tension spring 26 is connected at its ends to each of the -levers 24 and 25, thereby urging the levers towards each other. Suitable pins 27 mounted upon the bracket 21 limit the inward position to which these levers may be swung. Thus, it will be observed that in the absence of any actuating force upon the lever 23, the lever will be held in its neutral position by the spring actuated levers.

Suitabie operatingtmechanism is provided for causing the sha 20 to rotate within its bearings whereby either set of the movable contacts 12- or 13 may be moved into engagement with its corresponding set of stationary contacts. As shown, the actuating mechanism comprises a rotatable shaft 30 mounted upon the plate 11, the shaft 30 carrying an actuator or lever 32 keyed thereto and depending therefrom. The actuator 32 at its lower end is provided with a pair of spaced arms 33 which pivotally support a roller 34 between them. The upper end of the lever 23 is provided with a fork 35 comprising, as shown, a pair of oppositely disposed surfaces, which in any position of the lever, embrace the roller 34. Thus, it will be observed that upon swin ing motion being imparted to the depen in lever 32 in either direction, the lever 23 an consequently the shaft 20 are caused to rotate in one direction or the other as the case may be. Obviously the roller 34 may be eliminated and a stationary follower member substituted therefor, the roller however being provided to reduce .wear to a minimum. It will be further observed that as the levers 23 and 32 move from their aligned position, that the leverage between the two gradually increases, so that the force with which either set of the contacts 12 or 13 is moved into engagement with its corresponding set of stationary contacts increases gradually as the levers are so moved. In some cases it is desirable that the change of leverage be accentuated at the moment the contacts touch so that the force urging them together be increased, the fork 35 therefore is provided at its outer ends with flared surface 36, these surfaces being arranged at such an angle with the parallel surfaces 3? as to transmit this desired increase of which the roller 34'is adapted to engage.

Obviously the fork 35 may be designed to cause this abrupt change in leverage at any particular point in the path of movement of either of the moving contacts, and furthermore may be designed to cause a force of greater or less degree within wide limits to be applied to the moving contact. Any suitable means may be provided for rotating the shaft 30 whereby motion is in turn transmitted to the shaft 20, for example, a hand operated lever or handle 38 may be employed for this purpose.

In order that the lever 38 may not be initially moved from its neutral to its running position, suitable latching means is provided therefor. This latching means comprises a member 40 pivotally mounted upon the plate 11 and provided with two arced shaped recesses 41 and 42. A suitable member 43 is mounted upon the shaft 30 for cooperating with the latch 40. This member as shown is provided with 9. rectangular bore corresponding in cross section with that of the shaft 30 whereby it is keyed thereto. One end of the member 43 is provided with a projecting arm 45 and the other end is provided with a projecting plate 46, the arm 45 and the plate 46 forming bearing members for a pin 47 which is of such proportions that it may be engaged by either of the recesses 41 or 42 -within the latch 40. When the handle 38 is in its neutral position, as shown in Figure 1, the notch 41 engages the pin 47 preventing ahy movement ofthe lever 38 toward the left as viewed in Figures 2 and 3, that is, toward the running ition, but allowing movement towards t e right as viewed in those figures, that is, toward the starting position, because of the gradually inclined edge 41 of the recess, clearly shown in Figure 4. The lever 38, however, may be rapidly moved from the starting to the running position without interference by the latching member 40. It will be understood thatthe latch 40 due to its inertia falls with sufficient rapidit to cause'its notch 41 to enga e the pin 47 uring the rapid movement 0 the lever 38 from starting to running position. Thus, it will be observed that although the starting member may not be moved initially from the neutral to the running position it may be thrown directly from the starting to the runni position provided this movement is e ected at high speed. \Vhen the lever 38 is in its running position thepin 47 rests within the recess 42 of the latching member 40.

toggle so that-it may be ali of the lever from neutral to starting lever has been moved into its running rgized b Suitable lockin means is provided for the latch 40 so t at the lever 38 may be securely locked in its running position. As

shown, the locking means comprises a tog-.

it as the arm 50 is swung about the fixed pin Y 49 in a counterclockwise direction, as viewed in Figures 2 and 3. An electromagnet 52 is operably connected to the arm 50 by means of links 53 and 54 so that when the magnet is 'deenergized the arm is moved. about its pivot to break the toggle and when the ma net is energized the arm is withdrawn %rom the path of movement of the gned. It will be observed that when the lever 38 is in its neutral or starting position, the toggle will be broken whereby unobstructed movement P091 t1on and thence to runni mitted. However, when t e lever 38 is in its running ition, the toggle 48 will be aligned, as sii svn in Figure 3, thereby venting any upward movement of the 40. It will be understood that after the tion, the magnet 52 will be ene y some means either automatically or manually actuated so that the toggle m then ali 11 itself to lock the lever 38. Wlnen it is esired to move the lever 38 to its neutral position, the m net is deenergined and the to gle thereb broken. The lever 38 may t en be rea ily moved to its neutral position, the latch 40 permi unobstructed movement because of the gradually inclined edge 42' of the notch 42.

A latching mechanism is also provided for preventing rapid movement of the lever 38 from the running position through the neutral to the starting position, this latching mechanism however, rmitting the lever 38 to be moved slowly t rou h the neutral position. This latching mec anism comprises a latch 56 pivoted at a point near its center to the plate 11 and provided with a U shaped recess 57 in its forward end, the

runni the switch in its neutral positionf position is perrecess accommodating the pin 47 and being of sufiicient depth to allow the lever 38 to be fully moved to its starting position. A pin 58 supported between the arm 45 and the plate 46 serves to engage the latching member 56 as the lever 38 is moved to its position, thereby raising the latch upwar ly and holding it out of engagement with the pin 47. When the lever 38 18 mp idly moved from its running position toward its starting position through the neutral point, the pin 47 instead of being received within the recess 57 engages the end of the lower leg 59 of the U shaped recess, whereby further movement in that direction is arrested after which the latch falls to a position which does not interfere with further motion of the lever. the lever 38 be moved slowly through its neutral position, the bar 56 will slowly follow the in 58 in its downward movement and receive the pin'47, permitting uninterrupted movement of the lever 38 in this direction, the elongated upper leg 59 of the U shaped recess resting upon the pin 47 during this movement. It will be understood that the pin 58 is so positioned upon the plate 46 relative to the pin 47, and that the inertia of the latch 56 as governed by its mass and the osition of its pivot adjacent to its center is such, that the latch cannot rapidly follow the pin 58 in its .downward movement when the lever 38: is quickly moved. Thus, the latch functions" to provided it is being moved at ahigh rate 0 speed, consequent! preventing any danger of overtravel 0 the switching member.

In operation of the starting device, the lever 38 is moved from its neutral sition shown in Figure 1, toward its starting po- However, should I sition, that is, toward the right as viewed 7 in Figures 1 and 3, imparting motion to the lever 32 and con uently to the shaft 20. As the shaft 20 is t us rotated, the moving contacts 12. are moved toward their stationary contacts 12, the force by which they are i moved into engagement increasing rapidly because of the peculiar shape given to the l e ork member cam surfaces provided on 35. 'The lever 38 is then moved toward the left as viewed in Figures 2 and 3, through its neutral position and over to its running position, the contacts 13' likewise being moved forcibly into engagement with their stationary contacts 13, in which position the switching mechanism is locked by the interand perhaps cause engagement between the starting contacts, which action is prevented by the latch 56, which precludes any such rapid movement of the lever 38 through its neutral position.

While I have described my invention as embodied in concrete form and as operating in a specific manner in accordance with the provisions of the patent statutes, it should be understood that I do not limit my invention thereto since various modifications thereof will suggest themselves to those skilled in the art without departin from the spirit of my invention the scope c which is set forth in the annexed claims.

\Vhat I claim as new and desire to secure by Letters Patent ot the United States is:

1. A switch comprising, a plurality of stationary contacts, a plurality of movable contacts cooperating with said stationary contacts, an operating member for said movable contacts provided with a plurality of cams, one for each of said movable contacts, and an actuator member for selectively engaging said cams so as to cause said operat ing member to move the corresponding movable contact into engagement with its stationary contact.

2. A switch comprising, a stationary contact and a movable contact, a lever operably connected to said movable contact and having a cam surface thereon, means biasing said lever to normally maintain said movable contact out of engagement with said stationary contact, and means for engaging said cam surface for causing movement of said movable contact, said cam surface being arranged to cause aforce of increasing magnitude to be applied to said movable contact as the contacts move into engagement.

3. A motor controllin mechanism comprising, low voltage and ull voltage stationary contacts, movable contacts for cooperating therewith, a lever operably connected to said movable contacts for causing interengagement of either the low or high voltage contacts upon movement of said lever in one direction or the other, means biasing saidlever to a neutral position, and means for causing said lever to moi e in one direction or the other against said biasing means with a force of increasing magnitude.

4. A switch comprising, a stationary contact and a movable contact cooperating therewith, a switch arm supporting said movable contact, a shaft upon which said switch arm is mounted, an actuating shaft for imparting motion thereto, and means for transmitting motion from said actuating shaft to said first mentioned shaft arranged to cause said movable contact to be moved with a force of increasing magnitude as it engages said stationary contact.

5. A switch comprising, a stationary contact and a movable contact for cooperating therewithfa pivoted switch arm carrying said movable contact, a lever operably connected to said switch arm and having a cam surface at one end thereof with a portion parallel to the length of said lever and a portion disposed at an angle thereto, and an actuator for engaging said cam surface whereby said contacts are caused to move into engagement with a force of increasing magnitude.

6. A motor controlling mechanism comprising, low voltage and full voltage sta tionary contacts, movable contacts for cooperating therewith, a lever operably connected to said movable contacts and having opposed cam surfaces at one end thereof, an actuating lever having a portion disposed between said cam surfaces whereby said lever upon being moved in one direction causes interengagement of said low voltage contacts and upon being moved in the opposite direction causes interengagement of said full voltage contacts.

7. A controlling device comprising, an arm movable in either direction from a normal position of rest, and gravity actuated means for preventing rapid movement of said arm in one direction throu 11 its position of rest but permitting rapi movement therethrough in the opposite direction.

8. A controlling device comprising, a lever having a normal position of rest, gravity actuated latching means for said lever, and means. operated by said lever for controlling the movement of said latching means whereby said lever is prevented from being rapidly moved in one direction through its position of rest.

9. controlling device comprising, a lever having a neutral position, and a gravity actuated latching member therefor pivoted adjacent said lever and controlled by the motion thereof, said latching member permitting uninterrupted movement of said lever in one direction and engaging said lever to limit its movement in the opposite direction when said lever is moved with a predetermined speed.

10. Motor control means comprising, switching means movable in opposite directions from a neutral position to starting and running positions, means for biasing said switching means to said neutral ition, latching means for holding said switching means in said running position in opposition to its bias, and gravity actuated means for preventing movement of said switching means through the neutral ition to the starting position when said atching means is released.

11. A control device comprising, a lever having a neutral position, a pin' mounted upon said lever, a gravity actuated latch provided with a. U-shaped recess in one end thereof pivoted adjacent said lever, and

means carried by said lever for controlling the movementof said latch whereb when said lever is slowly moved toward its neutral position said pin is received within said U-shaped recess permitting unobstructed movement of the lever and whereb when said lever is rapidly moved toward its neu- I tral position said pin is engaged by a leg of the U-sha ed recess preventing continue movement 0 the lever.

In witness whereof, I have hereunto set my hand this 12th da of A ril, 1928. 1 CHARLE FL ARPENTER.

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