US2068553A - Operating mechanism - Google Patents

Description

Jan. 19, 1937. J. LINDE 5 OPERATING'MECI-IANISM Filed Dec. 28, 1934 Fig.2.

Inventor: Leonar'dlLinde,

is Attorn ey.

DISTANCE Patented Jan. 19, 1937 PATENT OFFICE OPERATING MECHANISM Leonard J. Linde, Aldon, Pa., assignor to General Electric Company, a corporation of New York Application December 28, 1934, Serial No. 759,555 11 Claims. (01. 200-89) My invention relates to operating mechanisms, more particularly to operating mechanisms of the trip-free type wherein means are provided for rendering ineffective the operating force during any part of the operating stroke, and has for its principal object the provision of an improved operating mechanism of the aforesaid type which is efficient and positive in operation,

simple and compact in design, and inexpensive.

in construction.

My invention will be more fully set forth in the following description referring to the accompanying drawing, and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming apart of this specification.

Referring to the drawing, Fig. 1 illustrates a preferred embodiment of my invention as applied to a switch or circuit breaker with the mechanismin the reset and open circuit position; Fig. 2 is a view of the mechanism during the operating stroke; Fig. 3 illustrates the mechanism in the operated or closed circuit position; Fig. 4 illustrates the mechanism in the tripped or nonoperative position, Fig. 5 illustrates graphically the design of the mechanism cam for approximating the operating characteristics of the means to be actuated, and Fig. 6 illustrates a. modified form of my invention.

'I'hemechanism illustrated by Fig. 1 comprises suitable actuating means as a solenoid l which in the present instance is operatively connected to a movable cam member 2. The solenoid may be of any suitable type and comprises energizing windings 3 and amov'able armature 4 of the plunger type to which, as at 5, is pivotally connected the cam member 2. The pivotal connection 5, which constitutes a floating pivotal mounting for the cam member, includes a roller which is guided for reciprocal movement in a slot 6 formed in a fixed guide I mounted on the frame 8 of the solenoid. v

The cam member 2 is provided with oppositely disposed operating faces 9 and ID for coacting respectively with means to be actuated and the tripping means as presently described, the arrangement being such that as the solenoid armature pulls the cam member upwardly the tripping means at the operating face I0 guides the cam member and holds it in operative engagement with the means to be actuated at the operating face 9.

To this end the means to be actuated, comprising in the present instance a switch element as a movable contact arm II, is provided with a roller i2 arranged to engage the cam operating face 9. The switch arm which is pivotally mounted at l3 carries at its upper end a contact H for cooperation with a fixed contact 15 and is normally biased in open circuit position as by a tension spring IS. The circuit between the breaker terminals-at i1 and I8 is completed in the closed circuit position by the contacts l4 and I5, switch arm II and flexible conductor IS.

The tripping means coacting with the cam face I!) comprises a roller 20 carried by a bellcrank 21 having a fixed pivot at 22. The crank arm 23 forms with a second bellcrank 24 a restraining toggle. The toggle is held in restraining position by a latch 25 coactingwith a roller carried by the crank arm 26. The toggle is held in an underset position by a fixed stop pin 21 as illustrated. The tripping force may be applied in any desired manner as by a tripping solenoid 28 having a movable armature 29 arranged to engage the latch 25 and rotate the same in a counterclockwise direction so as to release the crank 24 and permit collapse of the toggle.

In the position illustrated by Fig. 1 the solenoid is in the deenergized position, the cam member 2 being at its lower position, and the tripping means is reset, i. e., the tripping toggle held in restraining position by the latch 25. The switch arm spring l6 normally biases the roller 12 into engagement with the cam face 9.

The operating or closing stroke of the mechanism is initiated by energization of the solenoid I which results in movement of the armature 4 upwardly into the solenoid winding drawing with it the cam member 2. Since the tripping means acting on the cam face l0 guides, by means of the roller 20, the cam member and restrains the same with respect to counterclockwise rotation about its pivot at 5, relative movement between the cam operating face 9 and the roller I2 is effective to move the switch arm l2 in a direc tion' and at a rate dependent on the design of the cam face 9. As illustrated by Fig. 2, the contacts i4 and I5 are in engagement before the armature 4 is moved completely into the solenoid coilwinding, the cam member during'the operating stroke moving longitudinally between the rollers i2 and 20 and assuming varying angular positions by reason of its pivotal mounting 5.

The final part of the operating stroke presses the contacts i4 and I5 into high pressure contact engagement for minimizing resistance at the con. tacts, this part of the stroke being completed in the position illustrated by Fig. 3. x

The opening operation wherein the mechanism is returned to its inoperative reset position illustrated by Fig. 1 is effected by energizing the tripping solenoid 28. This results in releasing movement of the latch 25 and collapse of the toggle 23-24 which no longer restrains the cam member 2 in operative engagement with the roller l2. Accordingly, the cam member 2 is permitted to swing transversely or counterclockwise under the bias of the switch spring I! resulting in opening of the switch as illustrated by Fig. 4.

It will be noted, referring more particularly to Fig. 3, that the cam operating face a is provided with a reverse sloping surface at 3' arranged so that the roller II, under bias of spring It, serves to hold the cam member and the armature 4 in the upper or operated position at the end of the closing stroke. After the mechanism is tripped, as illustrated by Fig. 4, the cam member 2 and armature 4 drop to the lower position and the tripping toggle and latch reset, either under the influence of gravity or suitable springs, as illustrated by Fig. 1. The mechanism is now in its reset position in readiness for another cycle of operation.

It will be noted that the m is trip-free in operation, i. e., the tripping means can be released at any time during the closing stroke so as immediately to render ineffective the operat ing force on the means to be actuated. In other words. actuation of the tripping means during the middle of the closing stroke permits the cam member 2 immediately to move in a linear direction and swing coimterclockwise out of operative engagement with the roller I! so that the reenergy output of the actuating solenoid, the cam face I is so that the combined operating characteristics of the solenoid and cam face approximate those of the means to be actuated. This will be more clearly understood by reference toFlg.5whereintheareaunderthe curveAof the force-distance chart represents the work required in effecting the operating stroke on the means to be actuated. In the present instance the closing characteristics of a switch or circuit breaker are involved. During the first part of the clomng stroke only the frictional forces and spring resistance have to be overcome. This part of the stroke is represented up to the point m. At this point the contacts first engage and the opposing ruistance increases greatly as to the point a: due to flexingof the contacts, as in the case of laminated contacts, and the supporting contact structure in order to insure high pressure contact engagement. The completely closed position of the contact structure is represented at the point on.

After determination of the amount of work to be done, as represented by the area under curve' A, a solenoid is chosen the output of which is preferably of the order of 25 per cent in excess ofthe work required for the operating stroke. The operating characteristics of a plunger type solenoid of the character illustrated. are represented by curve B. The solenoid plunger travel point b to the end of the stroke represents overtravel of the plunger after the contacts are completely closed and movement of the cam surface I into et with the roller I! as illustrated in Fig. 3 for holding the cam member and phmger in the upper position.

The curve 0 represents the desired operating characteristics of the mechanism since it anticipates curve A. The area beneath the curve C is of course equal to the area beneath the curve B to the point I). The curve C preferably provides for a large initial accelerating force for overcoming the inertia of the mechanism.

From thesecurves and by using well known mechanical design methods the cam operating face may be plotted for each increment of travel of the cam member.

In regard to the cam face it cooperating with the tripping means, the design preferably is such that the force required to actuate the latch 25 is substantially constant. This is generally desirable in view of the fact that the tripping solenoid 28 may deliver a comparatively small tripping force.

Fig. 6 illustrates a modified form of my invention involving a reversal of the roller and cam members. In this arrangement a roller III is carried at the end of a link 3i which is in turn pivotally connected to the guide roller 5. The switch arm II is operatively connected to a cam member 32 having an operating face I! for coacting with the roller Ill. The roller and cam members are held in operative engagement by the tripping means comprising, in the present case, a toggle including a link I! and a pivoted member 34. The members 33 and N are pivotally connected at 35 and the link 33 is pivotally connccted at the roller to the roller actuating link iii. The free end of the pivoted member 34, as in the previous case, is adapted to be engaged by the tripping latch 25 which is actuated by the plunger 29 of the tripping solenoid 2|.

When the mechanism is reset with the latch 25 in restraining position (as illustrated by the dotted line position), actuation of the solenoid l is effective to pull the roller Jll upwardly through an are having as its center the pivot so as to cam the switch arm H counterclockwise towards closed circuit position illustrated by complete lines.

It will be apparent that the mechanism is tripfree in operation since release of the latch 25 during any part of the operating stroke will cause collapse of the toggle 3344, which is shown in an underset position, and swinging of the link II and roller 3|! in counterclockwise direction away from the cam member 32. As in the previous case, the cam operating face I! is preferably designed so as best to anticipate the operating characteristics of the means to be actuated.

It should be understood that my invention is not limited to specific details of construction and arrangement thereof herein illustrated, and that changes and modifications may occur to one skilled in the art without departing from the spirit of my invention.

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

1. Operating mechanism comprising actuating means and means to be actuated, a cam member, a roller member coacting'with said cam member. and tripping means for holding said roller and cam members in operative engagement, said tripping means operatively engaging one of said members, the other of said members being separately connected to said means to be actuated, said actuating means effecting relative linear movement between said roller and cam members for operating said means to be actuated.

2. Operating mechanism comprising actuating means and meanstobe actuated.'acammem- 7 aoeasss 3 her movable bodily in a linear direction, an element coacting with an operating face of said cam member, said actuating means effecting relative movement of said element and operating face in a substantially linear direction so that said means to be actuated is moved to an operated position, and tripping means for holding said element and cam member in operative engagement.

3. Operating mechanism comprising actuating means, a cam member bodily movablein a substantially linear direction operativcly connected to said means, means arranged to be actuated by movement of said member in said linear direction, and tripping means for maintaining said cam member in operative engagement with said actuated means during said movement and for restraining by means of said cam member said actuated means in an operated position, release of said tripping means causing movement of said cam member away from its actuating and restraining positions.

4. Operating mechanism comprising actuating means, a cam member pivotally connected to said means, means arranged to be actuated by said member, and tripping means for maintaining said cam member in operative engagement with said actuated members, release of said tripping means causing pivotal movement of said cam member away from said actuated means.

5. Operating mechanism comprising actuating means, a cam member movable in a substantially linear direction by said means, said cam member likewise movable transversely of. said direction, means arranged to be actuated by said cam memher during its movement in said linear direction,

and tripping means for restraining said cam member with respect to transverse movement in one direction and for maintaining said member in operative engagement with said actuated means, release of said tripping means causing transverse movement of said cam member away from its actuating and restraining positions.

6. Operating mechanism comprising actuating means, a cam member, means to be actuated including a roller arranged to bear on an operating face of said cam member, said actuating means effecting relative movement of said roller and cam operating face in a substantially linear direction so that said means to be actuated is moved to an operated position, said cam member movable in a direction away from said roller, and tripping means for restraining movement of said cam member in said direction and for maintaining said cam member in operative engagement with said roller, release oi said tripping means causing movementof said cam member away from its restraining position with respect to said roller.

7. Operating mechanism comprising actuating means, a cam member movable by said means in a given direction, said cam likewise movable in a direction transversely of said given direction, said cam member having oppositely disposed operating faces, means to be actuated including a roller arranged to bear on one of said operating faces, and tripping means including a roller arranged to bear on the opposite operating face for restraining movement of said cam member in a direction away from said first-named roller and for maintaining said cam member in operative engagement therewith, release of said tripping means causing transverse movement of said cam member away from its operating and restraining positions.

8. Operating mechanism comprising a solenoid, a cam member movable in a given direction by said solenoid, means to be actuated, said cam member having an operating face coacting with said means to be actuated characterized in that the combined operating characteristics of said solenoid and cam face approximate those of said means to be actuated, said cam member likewise movable in a directionaway from its operating position with respect to said means to be actuated, and tripping means for restraining movement of said cam member in said last named direction, said cam member likewise having an operating face coacting with said tripping means characterized in that the tripping force at said tripping means is substantially constant.

9. Operating mechanism of the trip free type comprising a solenoid, a cam member movable by said solenoid in a given direction, said cam member having operating faces at opposite sides thereof, means to be actuated including a roller arranged to bear on one of said operating faces, and tripping means including a roller arranged to bear on the opposite operating face of said cam member for maintaining said cam member and first named roller in operative engagement, actuation of said solenoid causing longitudinal movement of said cam member between said rollers, release of said tripping means at one side of said cam member permitting movement of said cam member out of operative engagement with respect to said first named roller.

10. Operating mechanism of the trip-free type comprising a solenoid, a cam member pivotally connected to said solenoid, said cam member having operating faces at opposite sides thereof, tripping means including a roller arranged to bear on one of said operating faces, said tripping means normally guiding in a given direction said cam member when the same is actuated by said solenoid, and means to be actuated including a roller arranged to bear on the opposite operating face of said cam member movement of said cam member in said guided direction causing movement of said means to be actuated to an operated position, release of said tripping means causing movement of said cam member to a non-operating position.

11. Switch operating mechanism of the tripfree type comprising a solenoid having a plunger, a cam member connected to and bodily movable in a given direction with said plunger, a switch element movable to open and closed circuit positions, said cam member having an operating face coasting with said switch element characterized in that the combined operating characteristics of said solenoid and cam member approximate those of said switch element, said cam member likewise movable independently of. said plunger in a' direction away from its operating position with respect to said switch element, and tripping means for normally engagin and restraining movement of said cam member in said last-named direction.

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