US3563102A

US3563102A - Spiral spring operating mechanism for high voltage switch

Info

Publication number: US3563102A
Application number: US846694A
Authority: US
Inventors: Joseph Bernatt; Benjamin L Gelfand
Original assignee: S&C Electric Co
Current assignee: S&C Electric Co
Priority date: 1969-08-01
Filing date: 1969-08-01
Publication date: 1971-02-16
Anticipated expiration: 1988-02-16
Also published as: GB1277722A

Abstract

A SPIRAL SPRING INTERCONNECTS A MANUALLY OPERATED DRIVE LEVER AND A TOGGLE LEVER CONNECTED TO A SWITCH. THE TOGGLE LEVER IS HELD IN SWITCH-CLOSED OR SWITCH-OPEN POSITON BY SPRING-BIASED TRIP LATCHES WHICH PERMIT THE SPRING TO BE STRESSED BY THE DRIVE UNTIL CAMS THEREON RELEASE THE LATCHES. THE SPRING PIVOTS THE TOGGLE LEVER TO THE ALTERNATE

POSITION WHERE IT IS STOPPED BY BUMPERS CARRIED BY A FRAME THAT SUPPORTS THE LEVERS ON AN OPERATING SHAFT ON WHICH THE SPRING IS MOUNTED.

Description

Feb. 16, 1971 v R A ETAL 3,563,102

SPIRAL SPRING OPERATING MECHANISM FOR HIGH VOLTAGE SWITCH Filed Aug. 1, 1969 4 Sheets-Sheet 1 N i 1 i 9;

3,563,102 SPIRAL SPRING OPERATING MECHANISM FOR HIGH VOLTAGE SWITCH Fild Aug. 1,

Feb. :16; 1971 'f-r' ETAL 4 Sheets-Sheet 2 Feb. 16,1971 R T ETAL SPIRAL SPRING OPERATING MECHANISM FOR HIGH VOLTAGE SWITCH Filed Aug, 1

4 Sheets-Sheet 3 hvi bNN Jv BERNATT E AL Feb. 16, 1971 SPIRAL SPRING OPERATING MECHANISM FOR HIGH VOLTAGE SWITCH Fil ed Aug. 1,

4 SheetsSheet 4.

wwO

United States Patent Office 3,563,102 Patented Feb. 16, 1971 3,563,102 SPIRAL SPRING OPERATING MECHANISM FOR HIGH VOLTAGE SWITCH Joseph Bernatt, Arlington Heights, and Benjamin L.

Gelfand, Chicago, Ill., assignors to S & C Electric Company, Chicago, III., a corporation of Delaware Filed Aug. 1, 1969, Ser. No. 846,694 Int. Cl. F16h 21/54; H01h 3/00 US. Cl. 74100 14 Claims ABSTRACT OF THE DISCLOSURE A spiral spring interconnects a manually operated drive lever and a toggle lever connected to a switch. The toggle lever is held in switch-closed or switch-open position by spring-biased trip latches which permit the spring to be stressed by the drive lever until cams thereon release the latches. The spring pivots the toggle lever to the alternate position where it is stopped by bumpers carried by a frame that supports the levers on an operating shaft on which the spring is mounted.

This invention constitutes an improvement over the construction disclosed in Harner et al. US. Pat. No. 3,339,118, issued Aug. 29, 1967 particularly with respect to the switch-operating mechanism disclosed therein and the disclosure thereof is incorporated by reference herein. In the patent over-center spring operating mechanisms are provided for shifting a switch between switch-closed and switch-open positions. They have the disadvantage that they may be rendered inoperative at about the center position resulting in failure to effect proper switch operation.

Among the objects of this invention are: To employ a spiral spring for operating a switch between closed and open positions in a new and improved manner; to wind the spring from one end or the other end depending upon the next switch operation; to interconnect a manually operated drive lever and a toggle lever connected to the switch by the spiral spring; to release the spring on operation of the drive lever through a predetermined extent after predetermined stressing of the spring; to latch the toggle lever in either the switch-closed or the switch-open position and to release the latches on pivoting of the drive lever; to limit the pivotal movement of the toggle lever in either direction at the end of the operating stroke; to directly interconnect the levers in the event that the switch should be stuck in the closed position; to arrange for tensioning the spring through different extents for the same angular movement of the drive lever in opposite directions; and to mount the spiral spring, levers and related operating parts in a frame, thus providing a unitary construction.

According to this invention the switch to be operated between open and closed positions is connected by a linkage to a mechanism drive arm which, together with a toggle lever, is pivoted on an operator comprising a manually operated shaft that is pivoted at its ends centrally of upper and lower frame members of a spiral spring operating mechanism. A hexagonal head on one end of the shaft receives a suitable tool for pivoting it. Other arrangements can be made for operating the shaft. Two latches on the lower frame member are biased toward the periphery of the toggle lever, which is generally circular with one or the other latch engaging a notch in the lever to hold it in either operated position. A drive lever secured to the shaft also is generally circular and carries cams for releasing the latches at the ends of the operating strokes. The spiral spring interconnects the levers through a spring arbor and a spring anchor, both pivoted on the shaft. A tang on the spring arbor extends through congruent arcuate slots in the levers for reaction against the ends of the slots to wind or discharge the spring. Tangs on. the levers react against the distal end of the spring anchor also to wind or discharge the spring. The latches are L-shaped with one arm of each latch pivoted on the lower frame member and the other arm of each latch overlying the peripheries of the circular portions of the levers for engaging the notch in the toggle lever and to be engaged by the cams on the drive lever. Bumpers carried by the lower frame member are engaged by the tang of the toggle lever to limit its movement in either direction.

In the drawings: FIG. 1 is a top plan of a three-phase switch module provided with a spiral spring operating mechanism embodying this invention. FIG. 2 is a view, in end elevation, of the switch module shown in FIG. 1. FIG. 3 is a view, in side elevation, of the switch module shown in FIG. 1. FIG. 4 is a view, partly in side elevation and partly in section and at an enlarged scale, of the spiral spring operating mechanism, the spring arbor being shown rotated through from the illustration thereof in FIG. 5. FIG. 5 is a horizontal sectional view taken generally along line 5-5 of FIG. 4 and looking in the direction of the arrows. FIG. 6 is a bottom plan view of the drive lever and toggle lever in offset relation, showing their relationships in the switch-closed position. FIG. 7 is a view, similar to FIG. 6, showing the drive lever and toggle lever in the positions that they occupy when the spiral spring operating mechanism has been operated so that the switch is ready to open. FIG. 8 is a view, similar to FIGS. 6 and 7, showing the positions of the drive lever and the toggle lever in the switch-open position. FIG. 9 is a view, similar to FIG. 8, and shows the relation of the drive lever and the toggle lever and the positions that they occupy when the spiral spring operating mechanism has been operated with the switch ready to close.

In FIGS. 1, 2 and 3 the reference character 10 designates, generally, a three-phase switch module which can form a part of 14 kv. pad-mounted gear, for example. It can be used for operating switches connected in circuits operating at higher or lower voltages. The switch module 10 is provided with a module frame that is indicated, generally, at 11 and it carries along one side insulated terminals 12 at the inner ends of which switch contacts, indicated generally, at 13, are mounted. Arc interrupting devices 14 can be provided for each of the switch contacts 13, for example as indicated in Jeffries application Ser. No. 813,541, filed Apr. 4, 1969. Associated with the switch contacts 13 are switch blades 15 that are separated by insulators l6 and pivotally mounted at the ends at 17 and 18 on upper and lower

module frame members

19 and 20. Shock absorbers 21 and 22 are mounted on the

frame members

19 and 20 respectively, for cushioning the opening and closing pivotal movements of the switch blades 15 and insulators 16. Collectively the switch contacts 13 and switch blades 15 are indicated, generally, at 23 and comprise a switch which is typical of the switch that can be operated by the spiral spring operating mechanism in which this invention is embodied.

The switch blades 15 of the switch 23 are shown in the switch closed position in FIGS. 1, 2 and 3. For pivoting them between the switch closed and the switch open positions, a driven switch operating arm 26 is employed which is pivotally connected at 27 to one end of a connecting link 28 the other end of which is pivotally connected at 29 to a mechanism drive arm 30 which is pivoted by a spiral spring operating mechanism, shown generally at 31. It will be understood that other switch constructions than the switch construction indicated at 23 can be employed in conjunction with the spiral spring operating mechanism 31.

The spiral spring operating mechanism 31 is mounted at the top of a side frame member 32 of the module frame 11 and at one end of the upper frame member 19. It includes a mechanism frame, indicated generally at 33, which is formed by upper and lower

mechanism frame members

34 and 35 that are shown more clearly in FIG. 4. Bolts 36 are arranged to hold the upper and lower

mechanism frame members

34 and 35 together and provide a unitary frame construction with the lower mechanism frame member 35 being suitably secured to the module frame 11 so that it is essentially rigid therewith. The spiral spring operating mechanism 31 includes an operator that is indicated, generally at 37 which has a hexagonal head for receiving a suitable tool for manual operation. It will be understood that other means can be employed for pivoting the operator 37 between the switch closed and switch open positions. As shown in FIG. 1 the switch blades 15 are arranged to be pivoted from the switch closed position, as shown by full lines, through an are 39 of the order of 75 to the switch open position indicated by broken lines. In order to effect this movement the mechanism drive arm 30 swings through an arc, indicated at 40, of the order of 120". Other relationships can be established as may be desired.

In FIG. 4 the mechanism drive arm 30 is secured at 45 to a toggle lever sleeve 46 which is journaled in a bearing bushing 47 that extends through and is carried by the lower mechanism frame member 35. Here it will be observed that the operator 37 comprises a shaft 49 having the hexagonal head 38 integral therewith at the upper end. The lower end of the shaft 49 is threaded to receive a nut 50 which bears against a washer 51 underlying the mechanism drive arm 30 and permitting relative pivotal movement. A bearing bushing 52 journals the upper end of the toggle lever sleeve 46 on the shaft 49. The upper end of the shaft 39 is journaled in a bearing bushing 53 that is carried by the upper mechanism frame member 34. Overlying it is a washer 54 that extends underneath the hexagonal head 38. If desired, the shaft 49 can be reversed with the head 38 at the lower end to which a manually operable lever can be attached.

The upper end of the toggle lever sleeve 46 is secured at 55 to a toggle lever 56 the outline of which is shown more clearly in FIG. 5. The toggle lever 56 is arranged to rotate about a vertical axis 57 which extends through the center of the shaft 49 and is indicated diagrammatically by the broken lines in FIGS. 6, 7, 8 and 9. The toggle lever 56 has a circular peripheray 58 for the major portion of its circumference and is provided centrally with a rectangular notch 59 having a bottom wall 60. The notch 59 is provided for cooperation with an arm 61 of an L-shaped trip latch, indicated generally at 62 and referred to in the claims as a first trip latch. It is employed for holding the toggle lever 56 in the position shown in FIGS. 5, 6, and 7 for example, corresponding to the closed position of the switch 23. The other arm 63 of the trip latch 62- is pivoted at 64 about a bearing bushing 65 which is carried by a latch support pin 66 that extends upwardly from and is secured to the upper side of the lower mechanism frame member 35. A torsion spring 67 reacts between the lower mechanism frame member 35 and the trip latch 62 for the purpose of biasing the latter in a counter-clockwise direction to bring the arm 61 into engagement with the circular periphery 58 of the toggle lever 56 and into the rectangular notch 59.

When the switch 23 occupies the open position, the toggle lever 56 occupies the position shown in FIGS. 8 and 9. Here the rectangular notch 59 is arranged to receive an arm 71 of an L-shaped trip latch that is indicated, generally, at 72 and is referred to in the claims as the second trip latch. The other arm of the trip latch 72 is pivoted at 7-4 in a bearing bushing 75 that is carried by a latch support pin 76, as shown in FIG. 4 and is mounted on and carried by the lower part of the lower mechanism frame member 35. A torsion spring 77 re- 4 acts between the lower mechanism frame member 35 and the trip latch 72 to bias it in a clockwise direction and the arm 71 into the notch 59.

For a purpose that will be set forth hereinafter, the toggle lever 56 is provided with an arcuate slot 80 having ends 81 and 82 that are about 150 apart.

Diametrically opposite the rectangular notch 59 the toggle lever 56 has a radial extension 83- provided with an upstanding tang 84 that is shown more clearly in FIG. 4. The toggle lever 56 is arranged to pivot between limits one of which is established by the tang 84 engaging bumper pad 85 of suitable resilient material which is carried by a lug 86 that is struck from the lower mechanism frame member 35. The other limit is established by engagement of the tang 84 with a bumper pad 87, FIG. 8, which is carried by a lug 88 that is truck from the lower mechanism frame member 35.

In FIGS. 4 and 5 the upstanding tang 84 is shown as engaging an out turned end 89 of a spiral spring that is indicated, generally, at 90. It is stressed and discharged to effect pivotal movement of the toggle lever 56 in a manner to be described. The out turned end 89 of the spiral spring 90 is secured by a rivet 91 to a down turned end 92 of a spring anchor 93 which is journaled on the shaft 39 by a bearing bushing 94. The other end of the spiral spring 90 is in turned, as indicated at 97, and it hooks over a wall 98 of a spring arbor that is indicated, generally, at 99. Bearing bushings 100 journal the arbor 99 on the shaft 49. The spring arbor 99 has a down turned tang 101 that is arranged to extend through the slot 80 in the toggle lever 56.

From the foregoing it will be observed that the mechanism drive arm 30, toggle lever sleeve 46 and the toggle lever 56 are secured together so that they can pivot conjointly on the shaft 49. The spring anchor 93 and the spring arbor 99 are independently journaled on the shaft 49 and are interconnected by the spiral spring 90.

Intermediate the ends of the shaft 49 there is a pin 102, FIG. 4 which extends into diametrically opposite slots 103, FIG. 6, in a drive lever that is indicated, generally, at 104. Thus the drive lever 104 rotates conjointly with the shaft 49 and about the axis 57 of rotation of the toggle lever 56 and parts secured thereto. The drive lever 104 has a circular periphery 105 for the major portion of its circumference the radius of which is not greater than the radial distance to the bottom wall 60 of the rectangular notch 59. This is shown more clearly inFIG. 5.

Radially extending cams

106 and 107, integral with the drive lever 104, are arranged to engage the trip latches 62 and 72 for disengaging one or the other of the

arms

61 or 71 from the rectangular notch 59 depending upon the last position of the operating mechanism 31 and of the switch 23. The drive lever 104 has an arcuate slot 110 therein the ends of which are indicated 111 and 112. The arcuate slot 110 is congruent with the arcuate slot 80 in the toggle lever 56. It will be noted in FIGS. 4 and 6 that the down turned end 101 from the spring arbor 99 extends first through the arcuate slot 110 in the drive lever 104 and then into the arcuate slot 80 in toggle lever 56. As shown more clearly here, the drive lever 104 has a radial extension 115 between the

cams

106 and 107 from which there is an upstanding tang 116 which is positioned to pivot inside the upstanding tang 84 on the toggle lever 56. The upstanding tang 116, like the tang 84, is arranged under certain circumstances to engage the out turned end 89 of the spiral spring 90 which is carried by the down turned end 92 of the spring anchor 93.

As pointed out, the ends 89 and 97 of the spiral spring 90 are connected respectively to the downturned end 92 of the spring anchor 93 and to the wall 98 of the spring arbor 99. Since the

upstanding tangs

84 and 116 react against the end 89 of the spring 90 while the tang 101 from the spring arbor 99 reacts against one or the other of the ends of the

arcuate slots

80 and 110, the spiral spring 90 is stressed mechanically between the toggle lever 56 and the drive lever 104. Preferably it is under substantial initial stress with the toggle lever 56 being held against pivotal movement by one or the other of the

latches

62 or 72

havingthe arm

61 or 71 in the notch 59, depending upon the pivotal position of the toggle lever 56.

In describing the operation of the spring operating mechanism 31 it will be assumed, first, that the switch 23 occupies the closed position shown in FIGS. 1, 2 and 3 and that the mechanism 31 is positioned as illustrated in FIGS. 4 and 5 and diagrammatically as indicated in FIG. 6. Here the toggle lever 56 is prevented from pivoting under the influence of the spiral spring 90 by arm 61 of the trip latch 62 engaging the notch 59. Pivotal movement of the toggle lever 56 in a clockwise direction also is prevented by engagement of the upstanding tang 84 with the bumper pad 85 carried by the lug 86 which is struck from the lower mechanism frame member 35. The spiral spring 90 is preloaded and the end 97 is prevented from moving in a counter-clockwise direction since it is hooked over the wall 98 of the spring arbor 99 and the downturned tang 101 thereof engages the end 82, FIG. 5, of the arcuate slot 80- in the toggle lever 56 which is held against movement in the manner above described. The out turned end 89 of the spiral spring 90 is prevented from moving in a clockwise direction since it bears against the upstanding tang 84 from the toggle lever 56. The drive lever 104 is partially held against counter-clockwise movement by the cam 107 bearing against arm 71 of the trip latch 72. The drive lever 104 is held against clockwise movement since the tang 101 from the spring arbor 99 bears against the end 112 of the arcuate slot 110, FIG. 6.

In order to open the switch 23, a suitable tool is applied to the hexagonal head 31 of the shaft 49 or other torque applying means is employed. It is shifted to pivot the drive lever 104 in counter-clockwise direction as viewed in FIG. 6. Cam 107 passes underneath the arm 71 of the trip latch 72 and the upstanding tang 116, integral with the drive lever 104, passes inside the upstanding tang 84 that is integral with the toggle lever 56 until the tang 116 engages the out turned end 89 of the spiral spring 90 which is secured to the down turned end 92 of the spring anchor 93. Continued pivotal movement of the drive lever 104 in a counter-clockwise direction winds up or stresses the spiral spring 90 since the other end 97 is held stationary by the spring arbor 99 acting through the tang 101 against the end 82 of the arcuate slot 80 in the toggle lever 56 which is held against movement by the engagement of the arm 61 of the trip latch 62 in the notch 59. As the counter? clockwise movement of the drive lever 104 continues, the

force exerted by the tang 101 on the end 82 of the arcuate solt 80 in the toggle lever 56 continues to increase until near the end of the cycle, which is illustrated in FIG. 7, where the cam 106 is approaching the arm 61 of the trip latch 62. On further counter-clockwise movement of the drive lever 104, the cam 106 pivots the trip latch 62 in clockwise direction, as viewed in FIG. 7, and lifts the arm 61 out of the notch 59 in the toggle lever 56. When the arm 61 is moved out of the notch '59 in the toggle lever 56, the spiral spring 90 drives through the tang 101 against the end 82 of the arcuate slot 80 to pivot the toggle lever 56 and therewith the switch 23 to the open position.

FIG. 8 shows the positions of the toggle lever 56, the drive lever 104 and the associated parts in the switch open position. Here it will be observed that the arm 71 of the trip latch 72 engages the notch 59 in the toggle lever 56 and thereby prevents counter-clockwise rotation. The shock incident to the opening movement of the switch 23 is absorbed to some extent by shock absorber 21. Also the tang 84 engages the bumper pad 87 to absorb additional energy incident to the opening of the switch 23.

In the switch open position, the toggle lever 56 is prevented from pivoting in a counter-clockwise direction, as viewed in FIG. 8, by engagement of the tang 84 with the bumper pad 87 as just noted. The toggle lever 56 is held against clockwise rotation since the arm 71 engages the notch 59. The spiral spring 90 is held against counterclockwise movement by tang 101 in continued engagement with the end 82 of the arcuate slot 80. The spiral spring 90 is held against clockwise movement since its out turned end 89 reacts against the upstanding tang 84 of the toggle lever 56. The drive lever 104 is prevented from movement in a counter-clockwise direction since tang 116 bears against the out turned end 89 of the spiral spring 90. The drive lever 104 is partially held against clockwise rotation by cam 106 in the path of the arm 61 of the trip latch 62.

If the switch blades 15 of the switch 23 should be welded to the contacts 13 or the switch 23 otherwise prevented from opening in the manner described solely under the control of the energy of the spiral spring 90, then continued application of torque to the hexagonal head 38 of the shaft 49 exerts a pryout action. Under these conditions the drive arm 30, through its pivotal connection to the connecting link 28 and thereby to the driven switch operating arm 26, holds the toggle lever 56 in the closed position shown in FIG. 7 while the drive lever 104 0ccupies the position shown in FIG. 8 since the cam 106 has released the arm 61 of the trip latch 62 from the notch 59. The torque of the spiral spring 90 exerted in a clockwise direction is resisted by the manual torque applied to the shaft 49 for opening the switch 23. Continued movement of the drive lever 104 in a counter-clockwise direction brings the end 111 of the arcuate slot 110 against the side of the tang 101 opposite its side engaging the end 82 of the arcuate slot in the toggle lever 56. When this occurs the shaft 49 is directly mechanically coupled through the drive lever 104, tang 101, and toggle lever 56 to the switch 23. The manual application of additional torque to the shaft 49 through the toggle lever sleeve 46 to the mechanism drive arm 30, connecting link 28 and the switch operating arm 26 is sufiicient to break the switch blades 15 away from the respective switch contacts 13 whereupon the spiral spring then is effective to pivot the toggle lever 56 in a switch opening direction until the tang 84 engages the bumper pad 87 as shown in FIG. 8. Latch 72 then engages the notch 59 in the manner previously described to hold the toggle lever 56 in the switch open position here shown.

In performing the pryout operation the drive lever 104 is pivoted past the normal switch open position shown in FIG. 8. This places the tang 116 beyond the tang 84 of the toggle lever 56 in a counter-clockwise direction. The end 89 of the spiral spring 90 and the spring anchor 93 then react against the tang 116 instead of the tang 84 as is the case for normal operation. The spring torque from the spiral spring 90 on the tank 116 under these circumstances then restores the drive lever 104 to the position shown in FIG. 8 as soon as the manually applied torque to the shaft 49 through the hexagonal head 38 is relaxed.

The switch 23 is closed by pivoting the drive lever 104 in a clockwise direction as view in FIGS. 8 and 9. Cam 106 passes underneath the arm 61 of the trip latch 62. The end 112 of the arcuate slot in the drive lever 104 engages the tang 101 of the spring arbor 99. Continued pivotal movement of the drive lever 104 in a clockwise direction by the shaft 49 as a result of torque manually applied to the hexagonal head 38% shifts the drive lever 104 to the position shown in FIG. 9 and the spiral spring 90 is correspondingly wound from the inside through the spring arbor 99. The outer end 89 of the spiral spring 90 attached to the down turned end 92 of the spring anchor 93 is held in the position shown in FIG. 9 by the tang 84 which is integral with the toggle lever 56 that, at this time, is held by the arm 71 of the trip latch 72 in the notch 59. The continued pivotal movement of the drive lever 104 in a clockwise direction from its position shown in FIG. 9 causes the cam 107 to pivot the trip latch 72 in a counter-clockwise direction and to move the arm 71 thereof out of the notch 59. Thereupon the toggle lever 56 is pivoted by the spiral spring 90 to the position shown in FIG. 6 as a result of spring torque exerted against the tang 84. In the switch open position the tang 84 engages the bumper pad 85 and further pivotal movement thereof is prevented and some of the shock incident to this action is absorbed. In addition, the shock absorber 22, engaged by arm 119 from the stack of insulators 16 cushions the closing movement of the switch 23.

It is possible to establish a definite driving torque for closing the switch 23 and establish a greater or lesser torque for opening it. The torques in each direction are independent of each other. Assume that it is desired to reduce the driving torque when opening the switch 23. The drive lever 104 is changed so that the cam 106 is positioned several degrees counter-clockwise from the position shown in FIG. 7, for example. Consequently, the counter-clockwise movement of the drive lever 104 movement will cause cam 106 to release latch 62 by a lesser angular movement of the drive lever 104. This will release toggle lever 56 at an instant when the spiral spring 90 has less windup or stress and consequently less torque. The toggle lever 56 then will be driven with lesser power and at a slower speed. Locating the cam 106 in a clockwise position with respect to that shown will, of course, produce the opposite effect. The driving torque for the closing cycle can be altered by re-positioning the angular relationship of cam 107 with respect to the drive lever 104. A clockwise movement of the cam 107 will advance the release point for the latch 72, thereby producing a lesser windup and delivered torque for the spiral spring 90. A counter-clockwise re-positioning will produce the opposite effect.

The total angular travel of the drive lever 104, whether opening or closing the switch 23, is equal and constant. Since the effective winding movement may be different in the opening cycle from the closing cycle due to desired power and speed differences, an element of pretravel is introduced. In counter-clockwise movement of drive lever 104 windup of the spiral spring 90 does not begin until tang 116 engages the out turned end 89 of the spiral spring 90. In clockwise movement of the drive lever 104 windup of the spiral spring 90 is delayed until end 112 of arcuate slot 110 engages 101. These preliminary angular motions, called pre-travel, are the remainders after subtracting the desired windup movement of the drive lever 104 from the total angular travel. Pre-travel plus wind-up travel equals total travel which is constant. This arrangement ensures that, upon releasing the energy of the spiral spring 90, no force or shock is imparted to the drive lever 104 and to the manual tool receiving head 38 in the event that the toggle lever 56 should catch up to the drive lever 104 before it reaches its final position where one or the other of the

springs

122 or 123 engages its

tooth

120 or 121. For holding the drive lever 104 in predetermined positions at the ends of its stroke,

teeth

120 and 121 extend radially therefrom as shown in FIG. 5.

U-shaped leaf springs

122 and 123, secured at 124 and 125 to the upstanding ends of the lower frame member 35, frictionally engage at their distal ends 126 and 127 the

teeth

120 and 121. In the switch closed position, shown in FIG. 5, the distal end 127 of the spring 123 engages the tooth 121. In the switch open position the tooth 120 is shifted to the position shown in FIG. 8 where the distal end 126 of the spring 122, FIG. 5, engages the tooth 120.

What is claimed as new is:

1. Mechanism for operating a switch between open and closed positions comprising:

a toggle lever for connection to said switch,

a drive lever pivoted about the pivot axis of said toggle lever,

a spiral spring coaxial with and interconnecting said levers,

a first trip latch for holding said toggle lever in switch closed position,

a second trip latch for holding said toggle lever in switch open position,

a first cam on said drive lever for releasing said first trip latch to cause said spiral spring to pivot said toggle lever and open said switch,

a second cam on said drive lever for releasing said second trip latch to cause said spiral spring to pivot said toggle lever and close said switch, and

an operator connected to said drive lever to pivot it in one direction to tension said spiral spring from one end or the other depending upon whether said switch is to be opened or closed.

2. Mechanism according to claim 1, wherein:

a spring arbor is pivoted about said axis,

one end of said spiral spring is connected to said spring arbor,

a tang on said spring arbor extends through arcuate slots in and coaxial with said levers,

a spring anchor is pivoted about said axis and is connected to the other end of said spiral spring, and tangs on said levers are arranged to react against said other end of said spring.

3. Mechanism according to claim 2 wherein a pair of bumpers in the path of a portion of said toggle lever limit pivotal movement thereof in opposite directions.

4. Mechanism according to claim 3 wherein:

upper and lower frame members pivotally mount said operator along said pivot axis, and

said toggle lever and said spring arbor are pivoted on said operator.

5. Mechanism according to claim 1 wherein:

said levers are generally circular plates,

said toggle lever has a notch in its periphery for receiving one or the other of said trip latches,

the major portion of the periphery of said drive lever extends below the bottom of said notch in said toggle lever,

said trip latches are generally L-shaped with one arm extending across the peripheries of both levers,

said cams on said drive lever extend radially beyond that portion of said toggle lever containing said notch,

means pivotally mount the other arms of said trip latches, and

spring means bias said trip latches toward the peripheries of said levers.

6. Mechanism according to claim 5 wherein:

said toggle lever is pivoted on said operator, and

said other arms of said trip latches are mounted on said lower frame member.

7. Mechanism according to claim 5 wherein:

a spring arbor is pivoted about said axis,

one end of said spiral spring is connected to said spring arbor,

8. Mechanism according to claim 7 wherein a pair of bumpers in the bath of a portion of said toggle lever limit pivotal movement thereof in opposite directions.

9. Mechanism according to claim 8 wherein:

upper and lower frame members pivotally mount said operator along said pivot axis,

said toggle lever and said spring arbor are pivoted on said operator, and

means mount said bumpers on said lower frame member.

10. Mechanism according to claim 9 wherein tool receiving means on said operator provide for manual pivoting thereof.

11. Mechanism according to claim 1 wherein spring means frictionally engage said drive lever to hold it in one or the other of its end positions depending upon whether the switch is open or closed.

12. Mechanism according to claim 11 wherein teeth on said drive lever adjacent said cams are engaged by said spring means.

13. Mechanism according to claim 1 wherein means pivoted by said drive lever operatively engage means connected to said spiral spring to tension it from either end after limited pre-travel of said drive lever in either direction.

14. Mechanism according to claim 2 wherein:

said tang on said drive lever has driving engagement with said other end of said spiral spring after limited pre-travel of said drive lever in one direction, and said tang on said spring arbor has driving engagement with one end of said slot in said drive lever after limited pre-travel of said drive lever in the opposite direction.

References Cited UNITED STATES PATENTS FREDERICK L. MATIESON, 111., Primary Examiner 15 W. S. RATLIFF, 1a., Assistant Examiner ZOO-153.7

US. Cl. X.R.