US2248387A

US2248387A - Circuit controlling mechanism

Info

Publication number: US2248387A
Application number: US288110A
Authority: US
Inventors: Theodore F Rosing
Original assignee: Cutler Hammer Inc
Current assignee: Cutler Hammer Inc
Priority date: 1939-08-03
Filing date: 1939-08-03
Publication date: 1941-07-08
Anticipated expiration: 1958-07-08

Description

July 8, 1941. r. F. ROSING ETAL CIRCUIT CONTROLLING MECHANISM Filed Aug. 5, 1939 2 Sheets-Sheet 1 Inventor's am- 3. Q. 56%

Deceased $W Execuirix b .w m.

Attorney Patented July 8, 1941 CIRCUIT CONTROLLING MECHANISM Theodore F. Rosing, Whitefish Bay, Wis., and

- William C. Stevens, deceased, late of Milwaukee, Wis., by Sally M. Stevens, executrix, Milwaukee, Wis., assignors to Cutler-Hammer, Inc., Milwaukee, Wis., a corporation of Delaware Application August 3, 1939, Serial No. 288,110

8 Claims.

This invention relates to electric circuit controlling mechanisms and is particularly applicable to manually operated switches of the trip free overload type.

The invention has among its objects to provide an improved switch of the aforesaid character which operates with a snap action when actuated manually or when tripped under overload conditions.

Another object is to provide a switch of the aforesaid character including a start push buttonfor closing the switch, a stop push button for opening the same, and a trip free overload mechanism which is resettable by the stop push button.

Another object is to provide a rugged, compact and efficient free tripping overload starter for polyphase alternating current motors.

Another object is to simplify and generally improve the construction and operation of starters of the aforesaid type .and to provide a structure which is made up almost entirely of sheet metal stampings and molded insulating parts which are cheap to manufacture and assemble.

Various other objects andadvantages of the invention will hereinafter appear.

The accompanying drawings illustrate an embodiment of the invention which will now be described, it being understood that various modifications may be made in the embodiment illustrated without departing from the spirit and A scope of the appended claims.

In the drawings, Figure 1 is a front elevational view of a starter embodying the invention;

- closed positions;

Fig. 5 is an enlarged fragmentary sectional view on line 5-5 of Fig. 2;

Fig. 6' is an enlarged fragmentary sectional View on line 6-6 of Fig. 1;

Fig. '7 is a sectional view on line' 3--3 of Fig. 1 illustrating the starter when tripped under overload conditions;

Fig. 8 is a bottom view of the switch mechanism shown in Fig. 1 illustrating certain of the parts of the overload mechanism in tripped position, and

Fig. 9 is a sectional view taken substantially on line 9-9 of Fig. 2.

Referring to Fig. l, the same illustrates a manually operated starter for polyphase alternating currentmotors including a switch unit I having a snap operating mechanism associated therewith including a start push button 2 and a stop push button 3. As hereinafter set forth said operating mechanism is of the free tripping type and has a pair of overload

responsive tripping devices

4 and 5 associated therewith, either of which is resettable by the stop push button 3.

Switch unit I is of the type disclosed in the copending application of T. F. Rosing and W. C. Stevens, Serial No. 271,731, filed May 4, 1939, and

includes a pair of stationary contact assemblies 6-6 and a movable contact assembly I. Briefly described the stationary contact assemblies 6-6 are of like construction, each including a molded insulating base 8 having a plurality of stationary contacts 9 mounted upon the front face thereof. Stationary contacts 9 are each provided with a terminal portion having a binding screw l0 associated therewith and the insulating bases 8--8 are vertically spaced and are removably mounted between forwardly extending side arms II of a U-shaped bracket I2 which is secured to a back plate I3 by screws I l.

. Movable contact assembly 1 includes an elongated flat insulating support l5 which is slidably supported between the insulating bases 88 and carries a plurality of bridging contacts I6 each of which cooperates with a pair of vertically alined stationary contacts 9. Insulating support I5 comprises arear section I! and a front section I8 which are secured together by hollow rivets I9, one of which is shown in dotted lines in Fig. 7 and bridging contacts I6 are yieldingly mounted in slots formed in the rear face of front section l8.

Insulating support I5 is secured to a. U-shaped bracket 20 by screws 2|, a plurality of removable shims 22 being interposed between said bracket and said support. As shown in Fig. 3 the shims 22 project beyond opposite sides of insulating support I5 to provide shoulders which cooperate with ledges formed on the insulating bases 8-8 to limit outward movement of contact assembly 1 beyond the position shown in Fig. 3.

Also as shown in Fig. 4 the side arms of bracket vided with a snap operating mechanism including a start push button 2 and a stop push button 3. Said push buttons are slidably mounted within openings in the front end of a forwardly extending U-shaped bracket 21 having spaced side walls 28. The inner ends of walls 28 are bent outwardly as shown in Fig. 8 to provide base portions which are secured to back plate |3 by screws 28 shown in Fig. 3.

Push buttons

2 and 3 are secured to forked

stems

38 and 3|, respectively, which are operatively connected by a pair of links 32-32 disposed on opposite sides of said stems. Links 32 are rotatably mounted upon a pin 33 which is located midway between the

stems

30 and 3| and is supported at opposite ends within openings in the side walls 28 of bracket 21. The upper ends of the links 32 are pivotally connected to stem 38 by a pin 34 while the lower ends of said links are pivotally connected to stem 3| by a pin 35. The

stems

38 and 3| are thus operatively connected to provide for movement of

push buttons

2 and 3 in opposite directions when either of the same is moved inwardly.

Push buttons

2 and 3 are operatively connected to movable contact assembly 1 through the medium of a cam 31 and a rocker arm 38. Cam 31 is pivotally mounted upon a pin 33 carried by bearing parts 40-40 which are located on opposite sides of said cam and are secured to the rear face of the connecting portion of bracket 20. The lower edge of cam 31 is shaped to provide a cam surface having a crest 4| and inclined faces 42 and 43 located on opposite sides of said crest, and said cam is also shaped to provide a stop projection 44 which extends downwardly from pivot pin 39 and is adapted to engage the rear face of bracket 20. Cam 31 is biased to move downwardly under the action of a pair of tension springs 45--45. As shown in Fig. 9 the upper ends of springs 45 are secured to parts 46-46 which are mounted on opposite sides of cam 31 and the lower ends of said springs are secured within openings in projections 41- 41 on the side Walls 28 of bracket 21.

Rocker arm 38 comprises a bifurcated element which is rotatably mounted upon a pivot pin 48 located intermediate the ends thereof. Pivot pin 48 is slidably mounted within vertically arranged slots 49 in projections 41 of bracket 21 and the upper end of rocker arm 38 carries a roller 50 for engaging the surface on the under side of cam 31, while the lower end of said rocker arm is provided with a slot for receiving a pivot pin 52 carried by the stem 30 of push button 2.

As shown in Fig. 3, pivot pin 48 is normally held against downward movement within the slots 43 in bracket 21 by a collapsible toggle 53 including a vertically arranged U-shaped link 54 and a pair of vertically arranged straight links 55. As shown in Fig. 9, link 54 is arranged between the side arms of stem 3| and the lower end thereof is pivotally mounted upon a pin 56 which is supported at opposite ends within openings in the side walls 28 of bracket 21. The lower ends of links 55 are pivotally connected to the upper end of link 54 by a pin 51 and the upper ends of links 55 are provided with openings for receiving the pivot pin 48 associated with rocker arm 38. As hereinafter set forth the links of toggle 53 are normally held against movement toward the; left beyond the position shown in Fig. 3, and as is apparent said toggle thus acts to normally hold rocker arm 38 against bodily movement in a downward direction.

The operation of the aforedescribed operating mechanism will now be more fully described. Cam 31 is normally held in engagement with the roller 50 on rocker arm 38 under the action of springs 45. Assuming that the aforedescribed parts are in the position shown in Fig. 3, upon depression of push button 2, stem 38 is moved inwardly to effect rotation of rocker arm 38 in a clockwise direction upon pivot pin 48. The roller 50 associated with rocker arm 38 is thus moved outwardly over the cam surface 42 on the under side of cam 31. During final movement of push button 2 into the position shown in Fig. 4 roller 50 assumes a position to the right of the crest 4| on cam 31 whereupon cam surface 43 coacts with said roller under the action of the spring 45 to move contact assembly 1, with a snap action into the closed position shown in Fig. 4. Assuming that the parts are in the position shown in Fig. 4, upon depression of stop push button 3 stem 3| is moved inwardly and stem 38 is moved outwardly through the medium of the links 32. Rocker arm 38 is thus rotated in a counterclockwise direction upon its associated pivot pin 48. During final movement of push button 3 into the position shown in Fig. 3 roller 50 assumes a position to the left of the crest 4| on cam 31 and the cam surface 42 then coacts with said roller under the action of springs 45 to return the movable contact assembly 1 with a snap action into the open position shown in Fi 3'.

As will now be set forth, when the above described switch mechanism is moved into circuit closing position the

aforementioned overload devices

4 and 5 are responsive under given overload conditions and when either or both of said devices respond the toggle 53 is tripped to permit opening of the switch with a snap action. Also as will now be set forth depression of push button 3 effects resetting of either of the overload devices upon response thereof and also effects resetting of toggle 53.

Each of the

overload devices

4 and 5 is provided with a supporting base 60 formed of molded insulation and as shown in Figs. 1 and 8 said bases are arranged on opposite sides of bracket 21 and are secured to the base portions of said bracket by the screws 29, shown in Figs. 3, 5 and 8. As shown in Figs. 5 and 9 each of the overload devices includes an overload responsive element 6| having a tripping member 52 associated therewith. Each of the overload responsive elements 6| includes a heater 63 of helical form arranged within a recess 64 in the outer face of its associated insulating base 68, a tubular member 65 surrounded by said heater and fixed within an opening in said base and a pin 68 located within said tubular member and normally held against rotation with respect thereto by a soldered connection 61. Each of the heaters 63 is connected to a pair of

terminal plates

63 and 53 mounted upon the front face of its associated base 50 and each of the pins 55 has a ratchet wheel 10 fixed to the inner end thereof to be engaged by a spring latch 1| fixed to its associated tripping member 62.

The switch tripping members 52 are preferably formed of molded insulation and are provided with elongated hub portions 12 which are rotatably mounted upon a pin 13 supported at opposite ends within openings in the inner faces of insulating bases 53. As shown in Fig. 3 the hub portions of said tripping members act as an abutment to limit inward movement of the

links

54 and 55 of toggle 53 beyond the position illustrated in Fig. 3. Tripping members 62 are provided with forwardly extending arms 14 whichcarry the spring latches H and the side walls 28 of bracket 21 are provided with openings for accommodating said members. The arms 14 of tripping members 62 are'both biased to move upwardly'under the action of a spring 15. As shown in Fig. 3 the front end of spring 15 is connected to the pivot pin 33 associated with links 32 and the rear end of said spring is con: nected to a pin it which is located to the rear of toggle link 54 and is loosely supported at opposite ends within openings in arms ll of tripping members 62.

The switch tripping members 62 are each normally held in a retracted position shown in full lines in Fig. 6 against the action of spring I5 by engagement oftheir associated latches II with ratchet wheels 18 of the overload responsive elements 6!. Each of the overload responsive elements 6i acts upon given overload conditions in its associated heater 63 to release its associated ratchet wheel and upon release of either ratchet wheel the tripping member 62 associated there'- with is rotated in a counterclockwise direction (Fig. '1) under the action of spring 15. Upon release of either or both of the tripping members 62 pin 76 moves forwardly to trip the toggle 53 and rocker arm 38 is then released to permit downward movement thereof into the position shown in Fig. "I. As is apparent from Figs. 3 and 4 the springs 45 are arranged to bias the movable contact assembly I toward open position and upon downward movement of the rocker arm 38 out of the position shown in Fig. 4 roller 50 disengages cam 3'1 to permit movement of said movable contact assembly into circuit opening position with a snap action.

The tripping members 62 and toggle 53 are reset by inward movement of stop push button 3. As is apparent from Fig. 7 upon inward movement of stop push button 3, the rear end of stem. 3| engages pin to move the same rearwardly for resetting of the tripping members 62 in normal position. As is shown in Figs. 8 and 9 stem 3| is provided with inwardly extending projections 1L4? which are arranged in front of the U-shaped toggle link 54, and upon inward movement of stop push button 3 said projections engage said link to effect resetting of toggle 53. As is apparent from Fig. 7 during resetting movement of push button 3 rocker arm 38 is Fotated in a counterclockwise direction and is also moved' upwardly by the toggle 53 to effect engagement of roller 50 with the cam surface 42. The switch operating mechanism is thus reset in the position shown in Fig. 3 to render the start push button 2 operable to efiect reclosure oi the switch.

The above described switch mechanism is provided with a mechanism for locking the same in circuit opening position. Such mechanism comprises a vertically arranged lever 18 having its lower end pivotally mounted upon the pivot pin 56 associated with the toggle link 54. As shown in Figs. 6 and 8 the upper end of lever 18 is provided with a lateral projection 18 which extends outwardly through a slot 88 in the left hand side wall 28 of bracket 21 and said lever is also provided with an inwardly extending projection 8| intermediate the ends thereof for engaging a projection 82 on the lower end of one of the links 32 associated with stems 38 and 3|. When the switch mechanism is in open position projection 19 may be moved upwardly in slot to move projection 8! into the path of projection 82 and as is apparent the switch operating mechanism is then looked in circuit opening position. In the embodiment illustrated lever 18 is releasably held in looking position by a spring latch 83 mounted upon the left hand side wall 28 of bracket 21.

The switch illustrated in the drawings is of the 3 pole type and may be connected in the conventional manner to eflfect control of a three phase alternating current motor. Also the above described switch mechanism may be mounted within an enclosing casing in the manner disclosed in our aforementioned copending application.

What we claim as new and desire to secure by Letters Patent is:

'1. The combination with a movable switch element biased toward open position, of a snap operating mechanism therefor having manual actuating means associated therewith, said snap operating mechanism including cooperating parts which are relatively movable to effect snap operation of said switch element and are disengageable to render said mechanism ineffective to hold said switch element in closed position, a toggle normally set to hold said parts in engagement and adapted to be tripped to effect disengagement of said parts and an overload mechanism responsive to trip said toggle, said overload mechanism and said toggle being resettable by said manual actuating means upon movement of the latter into switch opening position.

2. The combination with a movable switch element biased toward open position, of a snap operating mechanism therefor, including a start push button for effecting closure of said switch element and a stop push buttonufor effecting opening thereof, said snap operating mechanism also including cooperating parts which are relatively movable to effect snap operation of said movable switch element and are disengageable to disconnect said switch element from said push buttons. a mechanism normally set to maintain said parts in engagement and adapted to be tripped to permit disengagement of said parts and an overload device responsive to trip said mechanism, said overload responsive device and said mechanism being resettable by said stop push button.

3. The combination with a movable switch element biased toward open position, of a snap operating mechanism therefor, including a start push button for closing said switch element and a stop push button for opening the same, said mechanism also including cooperating parts which are diseng'ageable to render said mechanism ineffective to hold said. switch element in closed position, a collapsible toggle normally set to hold said parts in engagement and adapted to be tripped to effect disengagement thereof, and an overload mechanism responsive to trip said toggle, said toggle and said overload mechanism being resettable by depression of said stop push button.

4. The combination with a switch element biased-toward circuit opening position, of a start push button and a stop push button for operating said switch-,said push buttons being operatively connected to move in opposite directions, an operating mechanism between said push buttons and said switch element including a cam andan associated part for engaging said cam to render said push buttons operative to effect snap movement of said switch element in opposite directions between circuit closing and circuit opening positions, means normally set'to hold said cam and its associated part in engaging relation and adapted to be tripped to disengage said parts and thereby render said operating mechanism ineffective to hold said switch element in circuit closing position and an overload device responsive to trip said means, said overload device and said means being resettable by said stop push button upon movement thereof into circuit opening position.

5. The combination with a movable switch element biased toward circuit opening position, of a stop push button and a start push button for operating said switch, said push buttons being operatively connected to move in opposite directions, a cam element mounted upon said switch element, a part operable by said push buttons for engaging said cam to effect snap movement of said switch element in opposite directions between circuit opening and circuit closing positions, a toggle normally set to hold said operating part in engagement with said cam and adapted to be tripped to permit disengagement of said part from said cam and an overload device responsive to trip said toggle, said overload device and said toggle being resettable by said stop push button.

6. The combination with a switch element movable between circuit opening and circuit closing positions, a stop push button and a start push button for operating said switch element, said push buttons being operatively connected to move in opposite directions, a cam element pivotally mounted upon said movable switch element and having spring means associated therewith for biasing the same against pivotal movement in one direction and for also biasing said switch element toward circuit opening position, an operating part for engaging said cam, and movable with respect thereto to render said spring means operative to effect snap movement of said switch element between circuit opening and circuit closing positions, said part being operatively connected to said push buttons, a collapsible toggle normally set to hold said operating part in engagement with said cam and adapted to be tripped to effect disengagement of said part from said cam to thereby permit movement of said switch element into circuit opening position and an overload device responsive to trip said toggle, said overload device and said toggle being resettable by said stop push button.

7. The combination with a switch element movable between circuit opening and circuit closing positions, a cam pivotally mounted upon said movable switch element and having spring means associated therewith for biasing the same against pivotal movement in one direction and for also biasing said switch element toward circuit opening position, an operating part for engaging said cam and movable with respect thereto to render said spring means operative to effect snap movement of said switch element between circuit opening and circuit closing positions, said part having manual operating means associated therewith, a collapsible toggle normally set to hold said operating part in engagement with said cam and adapted to be tripped to effect disengagement of said operating part from said cam to thereby permit movement of said switch element into circuit opening position, and an overload device responsive to trip said toggle, said overload device and said toggle being resettable by said manual operating means upon movement thereof into switch opening position.

8. The combination with a movable switch element biased toward open position, a snap operating mechanism therefor including a start push button for closing said switch element and a stop push button for opening the same, said mechanism also including cooperating parts which are disengageable to render said mechanism inefiective to hold said switch in closed position, a collapsible toggle normally set to hold said parts in engagement and adapted to be tripped to efiect disengagement thereof, a plurality of electro-thermally controlled devices of the solder type, each of said devices including a heater to be energized upon movement of said switch element into closed position and a spring biased tripping part releasable automatically under given electrical conditions in said heater to trip said toggle and means associated with said stop push button for resetting any or all of said spring biased tripping parts upon release thereof and for also effecting resetting of said toggle.

THEODORE F. ROSING.

SALLY M. STEVENS, Executria: of the Estate of William C. Stevens,

Deceased.