US1741824A

US1741824A - Electric switch and closing mechanism therefor

Info

Publication number: US1741824A
Application number: US11885A
Authority: US
Inventors: George A Burnham
Original assignee: Condit Electrical Manufacturing Corp
Current assignee: Condit Electrical Manufacturing Corp
Priority date: 1925-02-26
Filing date: 1925-02-26
Publication date: 1929-12-31
Anticipated expiration: 1946-12-31

Description

Dec. 31, 1929. G. A. BURNHAM ELECTRIC SWITCH AND CLOSING MECHANISM THEREFOR Filed Feb- 26, 1925 2 Sheets-Sheet l Dec. 31, 1929. G. A. BURNHAM ELECTRIC SWITCH AND CLOSING MECHANISM THEREFOR Filed Feb. 26, 1925 2 Sheets-Sheet 2 Wm HF R ia Patented" Dec. 31, 1929 UNITED STATES 'PAT ENT OFFICE ononen a numvnm, or saucus, uassacnusn'r'rs, assrenon TO 001mm ELECTRICAL manuracruame coarona'rron, or BOSTON, MASSACHUSETTS, A conroaarron or MASSACHUSETTS v ELECTRIC SWITCH AND OLOSING HECHAHISM THEREFOR Application filed'lebruary 26, 1925. Serial No. 11,885.

actuated mechanism which is common to all.

of the switches and which may be called u on to close all of them simultaneously, or ut one of them. The reclosing mechanism is provided with suflicient power to close positively all of the switches of the gang and,

' therefore, has excess power when operated to close but one switch and so may close it with unnecessary speed and force; and the switch may be soviolently jarred that the latch will not engage to hold the switch closed and the switch may thereby open and draw a disastrous are between its switch members.

An object of thisinvention is the provision of means to govern the speed and force of the reclosing operation and, particularly, to provide means to decelerate the switch mechanism during the latter part of the closing movement, so that the switch will be closed positively but without unnecessary force.

While the ran e of movement of the movable switch mem er, between open and closed positions, may vary in different types or sizes of switches, the range .of movement of the switch-closing member of the reclosing mechanism is usually fixed or, at least, cannot readbe varied. Consequently, a further ob ect 11g o the invention is the provision of means, in-

terposed between the reclosing mechanism and the switch, to adjust the effective range of movement of the reclosing member to the range of movement of the actuating member of the switch, so that the switch may be closed without undue jar and also so that the switch will be moved into full closed position.

A, switch well adapted for automatic reclosing may include an actuating member for the switch mechanism, a latch or equivalent to lock the switch mechanism to the actuating member and a second latch to lock the actuating member to the face plate or other fixed support. While the reclosing mechanism may move the actuating member rapidly into closed position, the return movement of the reclosmg mechanism is relatively slow and, if the latch for the actuating member fails to lock, the actuating member may be moved slowly away from closed position and thereby gradually separate the switch contacts, which may result in harmful arcing. As a precaution against such action, it is a further object of this invention to provide means to trip the switch when the actuating member moves appreciably away from closed position.

A further object is generally to improve the construction and operation of electric switches and operating mechanism therefor.

Fig. 1 is a more or less diagrammatic representation of the invention associated with a gang of electric switches and an automatic reclosing mechanism therefor.

Fig. 2 is a fragmentary side elevation of the face plate of an electric switch associated with the invention. v

Fig. 3 is a plan sect-ion taken along the line 33 of Fig. 2.

Fig. 4 is a sectional view taken along the line 44 of Fig. 3. v s

Fig. 5 is a detail illustrating the disposition of the elements of the decelerating and stroke-limiting means in position to be opplate by the pivot pin 14 and a switch-operating rod 16 is pivotally connected with the upper end of said lever and extends to the switch not shown. An actuating member 18 is also pivotally mounted on sald pivot (pin 14 and carries a latch 20 whichis adapte to engage a latch-roller 22 carried by the upper end of said lever 12, whereby to lock said lever and actuating member releasably for conjoint operation. A second latch 24 is pivoted to the face plate and is arranged releasably to engage a latch-roller 26 carried by said actuating member whereby to lock said actuating member to the face plate and hold the switch closed. Said latch 24 is adapted to be actuate'd and disengaged from the actuating memher by an electro-magnet illustrated diagrammatically at 28 and controlled by the reclosing mechanism in a manner not important to this invention, for the purpose of causing the reengagement of said actuating member and lever after the switch has been tripped open by an overload or otherwise. Said latch 20 is adapted to be tripped whereby to cause the switch to open independently of a corresponding movement of said actuating memher by means including a tripping plate 30 disposed beneath the free end of said latch. Said tripping plate is supported loosely on and between three fulcrum supports 32, any one or all of which is adapted to elevate the plate to engage and trip the latch. Said fulcrum supports are actuated by solenoids 34 contained within the housing 86 of the face plate.

' As thus arranged, the switch may be opened and the lever 12 will move toward the left, Fig. :2, without a corresponding movement of the actuating member 18 and said actuating member subsequently is adapted to be released from the face. plate and moved toward the left to be again latched to said lever before the switch can be reclosed.

The switches are adapted to be reclosed by means including the bar 38. Said bar is disposed horizontally beneath the face plates of the switches and is pivotally-connected with the lower arms of bell-crank levers 40. Said bell-crank levers are pivoted at 42 to the upper ends of pedestals 44; and said pedestals are supported in line on a suitable base 46. Said bar 38 is adapted to be reciprocated in the direction of its length, whereby to reciprocate said bell-crank levers and efi'ect the closing of the switches. Yokes 48 are pivoted to the upper arms of said bell-crank levers and rods 50 are screw-threaded adjustably in said yokes. The upper ends of said rods are disposed slidably in cylinders 51. Helical compression springs 52 are disposed in said cylinders about said rods and between the enlarged heads 54 of said rods and abutments 56 of said cylinders, whereby to form lost motion connections between said bar 38 and the switches. Caps 58 or the equivalent are screw-threaded on the upper ends of said cylinders and. are pivoted at 60 to arms 62, which arms are fixed to and are extended forwardly of the actuating members 18 of the member 74 is pivoted'to one end of said lever 64 and the lower toggle member 76 is pivoted to a fixed support 78. Said spring, through said toggle, tends constantly to urge said lever 64 for movement in a clockwise direction. The action of said spring is controlled, and the spring is placed under stress, by a cam 80, which cam is fixed to a shaft 82. The free end of said lever 64 is provided with a roller 84 which is adapted to ride upon the cam. Said cam is provided with a cam face of more or less spiral formation and an abrupt drop-portion 80 and is so arranged that it operates gradually to raise the end of said lever 64 and thereby stress said spring 68 and then suddenly release the lever, whereupon the spring serves to move the lever over the distance provided by the drop-portion 80 and effect the closing of the switches. The normal position of the cam and lever are illustrated in dotted lines, in which position a relatively slight rotation of the cam in a clockwise direction serves to release the lever 64 and effect the closing of the switches. The drop-portion 80 of the cam is formed or provided with a more gradually inclined lower face 8O which is arranged to decelerate the movement of the lever 64 at the lower end of its stroke, and thereby decelerate the closing movement of the switch mechanism during the final part of such movement.

The cam is rotated by an electric motor 85 through suitable speed-reducing gearing 86 and is adapted to be. set in operation in any suitable manner, not necessarily shown, by the opening of a switch. The first operation of the mechanism is to effect the closing ofthe switch and the further movement of the cam serves to restress the spring 68 and rc-condi' tion it for a second switch-closing operation. Means, not shown, are provided to stop the motor with the cam in its dotted line position.

In accordance with this invention, means are interposed between the reclosing mechanism and the switch to decclerate the closing movement and also to limit such movement, whereby to close the switches without undue shock. Said means includes a toggle mechanism one member of which comprises the arm 90 of a bell-crank lever 91. Said bell crank lever is pivoted to a fixed support 92 at A link 93, comprising the other member of the toggle mechanism, is pivoted to the upper arm of a bell-crank lever 94, the lower arm of which lever is pivoted to the bar 38. The lever 64 of the reclosing mechanism is connected with the other arm 95 of said bell crank lever 91 by means including a link 102 which is pivotally connected to said lever 64 and to the upper end of a rod 104, the lower end of which rod is pivotally connected, at 106, with the arm 95 of said bell crank lever 91.

VVhen'the reclosing mechanism is in con-- dition for switch-reclosing, and the cam and lever thereof are in the dotted line position, said toggle is about in the position illustrated in Fig. 5. When one or more switches open and the reclosing apparatus is operated to reclose them, the upward movement of said rod 104 is transmitted through said toggle to the bar 38 and moves sa1d bar toward the left and the toggle, during this movement, straightens out. Due to the increasing angle between the toggle members,

during the closing operation, the closing movement of the operating parts is decelerated uniformly and smoothly so that the switches may be closed without undue mechanical shock. The maximum throw of the bar 38 ina closing direction is restricted by the length and arrangement of the toggle members which, when the three pivot points 92 98 and 99 are in line, restrain the bar against further movement in a closing direc- 2 tion. While the toggle decelerates the final part of the closing movement of the switch mechanism, it also acts to increase the force of reclosing, so that theswitches are finally closed with increased power and yet without shock. If the dimensions of the cam 80 of the reclosing mechanism are such that the lever 64 is not in. contact with the bottom of the drop-portion 80 when the toggle members are on center, the closingspring 68 serves merely to move the toggle members beyond center until the cam restricts further movement. Such movement of the toggle members serves merely to move the bar 38 in the reverse direction but suchmovcment does not affect the switches as they will have been latched closed previously and the movement is taken up in the lost motion connections between the switches and bar. The dimen- :sionsand arrangement of the toggle members :40 may be varied to the extent of travel of the switch mechanism between open and closed positions whereby tolimit the extent of movement of the bar 38 regardless of the movement that ordinarily would be imparted to the bar by the closing cam 80.

The first part of the rotary movementof the cam 80 serves to effect the switch-closing operation' and the remaining movement is utilized to re-stress the closing spring 68. The movement of the cam is relatively slow and the movement of the bar 38 and associated mechanism is correspondingly slow. If, during the reclosing operation, a latch 24: for an actuating member 18 of a switch fails to hold the actuating member in closed position, said member may slowly move out of closed'position, following the spring re-stressing movement of the mechanism, and draw a disastrous are between the contact members of the switch. As a precautionary measure, therefore, means are provided to trip the latch 20 and thereby cause the switch to open at opening speed if said actuating member moves appreciably away from closed position. Said meansin'cludes a relatively flexible finger 110 which is attached to and movable with the actuating member 18 and projects rearwardly therefrom and over the tripping plate 30. Said tripping plate 1s provided with an upstanding arm 112 which terminates in a hook 114. WVhenthe actuating member is moved into closed position said linger 110 is moved to ride over the upper face of the hook and occupy a position beneath the hook, see Fig. 4. When the actuating member is moved away from closed position, said finger serves to raise the tripping plate and cause it to engage and trip the latch 20, thereby causing the opening movement of the switch. Said finger 110 is formed with a cam face 116 which isadapted to engage said hook 114 for such purpose.

The structure may be otherwise modified without departing from the spirit of the invention.

I claim:

1. The combination of a gang of electric switch mechanisms adapted for conjoint and also for independent closing, normallystressed, quick-acting closing mechanism arranged to close any switch mechanism that may be open and also all of said mechanisms conjointly, and operative connections between said switch mechanisms and said normallystressed closing mechanism including decelerating means in said connections? 2. The combination of electric switch mechanism, normally-stressed, quick-acting closing mechanism therefor, and means connecting said switch and closing mechanisms including means arranged to progressively reduce the closing speed of said switch mechanism relative to the speed of said closing mechanism during the switch closing movement thereof.

3. The combination of electric switch mechanism, closing mechanism therefor having an actuating member, a normally stressed spring for actuating said member, a cam for stressing and controlling the action of said spring, an operative connection between said actuating member and switch mechanism, and means interposed in said connection arranged to progressively reduce the closing speed of the switch mechanism relative to the closing speed of the closing mechanism.

4. The combination of electric switch mechanism, normally-stressed, quick-acting closing mechanism therefor including an actuating member having a rapid movement from switch open to switch closed position, and an operative connection between said actuating member and saidswitch mechanism including an interposed toggle arranged to be moved by said actuating member into approximately on-center position when the switch is in closed position. 5. The combination of mechanism, ed closing electric switch normally stressed power-actuatmechanism therefor including a.

reciprocatory member, a normally stressed spring for actuating said reoiprocatory memher and moving said switch mechanism into completely closed position, and an operative connection between said switch mechanism and reciprocatory member including a motion-decelerating toggle free to move on both sides of a center position and move the switch mechanism into switch-closed position, in which position, the toggle is arranged to be approximately on center position.

6. The combination of a gang of electric switch mechanisms each including means to hold its mechanism in switch-closed position, said mechanisms arranged to open independently of each other, power-actuated closing mechanisms for the switch mechanisms, means operatively connecting said switch mechanisms with said closing mechanism including a lost-motion connection between each switch mechanism and said closing mechanism arranged to provide for the operation of said closing mechanism when one or more of said switch mechanisms are closed,

anda toggle between said closing mechanism and said lost-motion connections movable on both sides of center position and constructed and arranged to move the switch mechanism into switch-closed position when approximately on center position.

7. The combination of electric switch mechanism including means to hold the mechanism in switch-closed position, normally stressed power-actuated closing mechanism for the switch mechanism including a movable member, means operatively connecting said movable member and switch mechanism including a lost-motion connection and a toggle governing the extent of movement of said switch mechanism and arranged for movement on both sides of an on-center position.

8. The combination of electric switch mechanism, power actuated mechanism thereior including a cam-governed lever, an

operative connection between said lever and switch mechanism including a longitudinally-movable bar, a lost-motion connection between the switch mechanism and said bar, and a toggle connecting said bar and camactuatcd lever.

9. The combination. of electric switch mechanism, power-actuated closing mechanism therefor including a cam-governed lever, an operative connection between said lever and switch mechanism including a longitudinally-movable bar, supporting means for said bar including pivoted bellcrank levers, a lost-motion connection between said bar and switch mechanism, togglemembers pivotally connected with one of said bell-crank levers, and a connecting rod pivotally connected with one of said toggle members and with said cam-governed lever.

10. Electric switch mechanism including ving sai a pivoted lever movable in opposite directions to close and open the switch, an actuating member movable between switch-open and closed positions, means releasably connecting said lever and actuating member, means to hold said actuating member and consequent ly the switch mechanism in closed position, and means operated upon the failure of said holding means to release the connection between said actuating member and lever and permit said lever and consequently the switch to open rapidly independently of said actuating member.

11. Electric switch mechanism including a pivoted lever movable in opposite directions to close and open the switch, an actuating member movable between switch-open and closed ositions, means releasably connect d lever and actuating member, power actuated means to move said actuating member to switch closed position and subsequent- 1y to bias it for switch opening movement,

holding means for said actuating member normally resisting such movement and tripping means for said connecting means actuated by a movement of said actuating member away from switch closed position due to failure of said holding means, whereby to open the switch rapidly independently of said power-actuated means.

12. The combination of electric switch mechanism including a switch-operating member movable in opposite directions to open and close the switch, an actuating member movable between switch-open and closed positions, means releasably connecting said actuating member and switch-operating member, a latch arranged releasably to hold said actuating member in switch-closed position, power actuated closing means for said switch mechanism including means biasing said actuating member for switch-opening movement, and means actuated upon failure of said latch to break said connecting means and effect the opening of the switch independently of said actuating member.

13. The combination of electric switch mechanism including a switch-operating member movable in opposite directions to open and close the switch, an actuating member movable between switch-open and closed positions, means releasably connecting said actuating member and switch-operating member, power-actuated closing mechanism for said switch mechanism including means associated with said actuating member and arranged to move rapidly in a switch-closing direction and slowly in a switch-opening direction, and means actuated by a movement of said actuating member away from closed position to break said connecting means and efiect the opening of the switch independently of said actuating member.

14. Switch mechanism including a pivoted switch-operating lever, an actuating member therefor, movable between switch-open and closed positions, a latch arranged releasably to connect said lever and actuating member, a tripping plate for said latch, and means governed by a movement of said actuating member away from switch-closed position to trip said latch including a finger carried by v and extended rearwardly from said actuating member and terminated in a cam-face, and a hook carried by said tripping plate arranged to be engaged by said cam-face to move said tripping plate and trip said latch.

15. Switch mechanism including a pivoted switch-operating lever, an actuating member therefor movable between switch-open and closed positions, a latch arranged releasably to connect said lever and actuating member, a tripping plate for said latch, and means governed by a movement of said actuating member away from switch-closed position to trip said latch including a finger carried by and extended rearwardly from said actuating member and terminated in a cam-face, and a hook carried by said tripping plate arranged to be engaged by said cam-face to move said tripping plate and trip said latch, said finger arranged to ride over said hook in a switch member closing movement of said actuatin without efi'ectively actuating said plate.

16. The combination of a plurality of independent electric switch mechanisms including means for locking them independently in switch closed position, a common power-actuated mechanism for closing any switch mechanism that may be open and also all of said switch mechanisms collectively, and decelerating means operatively connecting said closing mechanism with said switch operating mechanisms, said means including a toggle adapted to move to center position at the end of the switch closing movement.

17 The combination of a switch closing mechanism adapted to move from normal position to close a switch and thence to return slowly to normal position, a switch mechanism associated with said closing mechanism and capable of moving therewith between closed and open positions, means to hold the switch mechanism in closed position, and means rendered operative upon the failure of said holding means to effect the rapid open: ing of said switch mechanism independently of a corresponding movement of said closing mechanism. r

In testimony whereof, I have signed my name to this specificatio GEORGE A; BURNHAM.