US2773956A - Front operated disconnect switch - Google Patents

Description

Dec. 11, 1956 D. w. JOHNSON 2,773,955

FRONT OPERATED DISCONNECT SWITCH Filed Oct. 21., 1953 2 Sheets-Sheet l flcm/cdn. JZJUISOTL f/IS ATTORNE Y5 1956 D. w. JOHNSON FRONT OPERATED DISCONNECT swmn 2 Sheets-Sheet 2 Filed Oct. 21, 1953 i 3 j INIENTOR. fitu/tZWJoiurSom Y QM &1, H/I/l TTOR IVE Y United States Patent FRONT OPERATED DISCONNECT SWITCH David W. Johnson, Newington, Conn, assignor to The Arrow-Hart & Hegeman Electric Company, Hartford, Conn., a corporation of Connecticut Application October 21, 1953, Serial No. 387,407

13 Claims. (Cl. 200-73) This invention relates to electric switches. More particularly it relates to switches especially useful as disconnect switches operable from the front but the invention is not limited to such use. in breaking electric circuits, it is frequently desirable to cause the contacts to separate initially with a slow motion for a short distance and thereafter to snap into fully open or off position. That desire is achieved by a novel structural combination in this invention.

Therefore it is an object of this invention to provide an electric switch operated from the front having a pro vision for slow separation of the contacts initially followed by a rapid break in the same direction, the rapid break not being subject to a control of the operator after the snapping action starts. I

Another object of the invention is to provide a switch of the foregoing type which may be economically manufactured and will withstand long continued use and which will have a higher rating than switches normally used in disconnecting electric circuit with a snapping action.

Other objects and advantages of the invention will appear as it is described in connection with the accompanying drawings.

In the drawings:

Fig. 1 is a top plan view of a switch embodying the invention.

Fig. 2 is a longitudinal section view taken along line 22 of Fig. 1.

Fig. 3 is a fragmentary detail sectional view with a section being taken along line 33 of Fig. 2.

Fig. 4 is a fragmentary detail view showing in bottom plan the operating mechanism as appears when the bottom cover plate is removed.

Fig. 5 is a fragmentary detail view illustrating in bottom plan the relation of the actuating member and associated parts removed from beneath the mounting plate, the parts being in the same position as those in Fig. 4.

Figs. 6 and 7 are views similar to Figs. 4 and 5 respectively, but showing the parts in an intermediate position between on and fully off position.

Figs. 8 and 9 are views similar to Figs. 4 and 5 but showing the parts in fully off position. v

Fig. 10 is a fragmentary detail view showing in bottom plan the driven member of the snapping mechanism.

Referring to the drawings, the switch may be mounted in a base 11) made of insulating material and provided with three connected central recesses 12 positioned transversely along the base and running from front to back. Connected with the three recesses 12 are three recesses 13 on each side of the switch base containing terminal members 14, connected with which are pairs of fixed contact members such as 15 and 16 extending from the terminal recesses 13 into the central contact recesses 12. The terminal and contact members may be stamped as one part from sheet metal.

For engaging and disengaging the three pairs of stationary contacts 15 and 16, three similar bridging contacts 25, 26 and 27 stamped from sheet metal in bar form are mounted upon a contact carrier 20. The contact carrier may conveniently be molded from insulating material with a central rectangular spine 21 from the opposite sides of which extend arms 22 and 23 lying within the recess 12. In order to mount the movable contacts resiliently upon the carrier, contact receiving recesses or passages 24 are formed in the carrier, through which passages may extend the bridge contacts 25, 26 and 27. Pressing the bridging contact toward the fixed contacts are coiled compression springs 28, one end of each of which presses upon the back of the movable contact member while the other end presses against the carrier so that when the carrier is moved into switch-closed position, the bridging contacts will engage and automatically adjust themselves against the fixed contact pairs.

In order to move the contact carrier 20, a small notch or recess 29 is formed in the bottom surface thereof to receive a lug 71 bent up at right angles from the end of an actuating member 70 which slides in a guideway 17 formed in the under side of the floor of the insulating base 10. The actuating member or slide 70 may conveniently be stamped from sheet metal in bar form with a recess or spring receiving aperture 74 in one end portion thereof. Said end portion is offset from the other end forming a shoulder 76 which is adapted to be engaged at proper time by an actuating pin 31 on the switch spindle 36 as will hereinafter be more fully described. The actuating member 70 is normally pressed by a hairpin coiled spring 72 toward open circuit position. The hair-pin spring may be seated in a deep spring receiving recess 78 in the under side of the floor of the insulating base with one end 77 pressing against the edge of the recess. The other end of the spring presses against a spring anchor lug 73 struck down from the actuating member 7 0 at one side thereof.

In order to overcome the biasing movement of the hair-pin spring 72, a finger or lug 59 (formed on the driven member 50, of the snapping mechanism as will hereinafter be more fully described) extends into the opening 74 in the slide 70 and is adapted to press against a coil compression spring 75 located within one end of the opening 74. The portion of the opening in which the spring 75 is located preferably is of rectangular shape and of width to receive the spring 75. Expansion of the spring 75 is limited by its abutment against the opposite ends of the rectangular portion of said aperture. As the actuating finger 59 moves with the driven member 50 between the position shown in Figs. 5 and 9 (which are equivalent to positions shown in Figs. 4 and 8) the actuating finger 59 moves from switch oil position as shown in Fig. 9 wherein the finger is entirely out of the engagement with the spring 75 into the position of Fig. 5 wherein the finger pressing against the spring 75 causes the slide 70 to move against the bias of the hair-pin spring 72. This movement causes the contact carrier to move from switch open to switch closed position. Since the coil spring 75 is stronger than the hair-pin spring 72, the bias of the latter is overcome.

The mechanism for manually operating the switch to cause separation of the fixed and movable contacts at first with a slow break and finally with a snap action comprises a switch spindle 30 extending through the switch base 10 from front to back. The spindle may be operated directly by a handle 32 or in any suitable fashion. The opposite end of the spindle from that upon which the handle is mounted extends through a stamped sheet metal mounting plate 18 fitted into a large recessed area formed in the back or bottom surface of the insulating base 10. This mounting plate is secured to the base and upon it is mounted the mechanism actuated by the movement of the switch spindle except for the slide '76 which is located between the mounting plate and the switch base in the longitudinal guideway in which the slide is located.

Fixedly mounted upon the bottom or end of the spindle 36 is a flat disc-like sheet metal stamping forming the outer part 33 of the driving member of the snapping mechanism. At spaced points on the periphery of the driving disc 33 are radial teeth 34 and 35 which are adapted to positively engage a spring anchor lug 55 on a driven member 54) (hereinafter to be more fully described) so that in the event that the snapping spring breaks, the switch can be operated manually "between openand closed-circuit positions.

Secured to and turning as a unit with the outer disc member is aninner stamped sheet-metal disc-shaped driving element 40. It is spaced from the outer disc 33 but secured thereto by arms 44, 45. These arms are bent up from. the plane of the inner disc 40 at diametrically opposite positions into parallel relation with each other and with the spindle axis. On;the ends of the arms 44 and 45 are fingers engaging in radial notches or recesses in the periphery of the outer disc 33, the fingers being bent over to thus secure the outer and inner driving discs in spaced relation. Between these two discs is located a spring which is coiled around the switch spindle with its ends extending substantially radially outward on opposite sides of the arm 45. Between the inner driving disc 40 and the mounting plate 18 and loosely mounted upon the switch spindle 30 is a driven stamped sheet-metal disc having a radially extending arm or lug 55 bent up to lie parallel to the axis of the switch spindle outside the arm 45 and in alignment therewith. The extending ends 36a and 36b of the snapping spring 36 thus engage opposite sides of both the driven arm 55 and the driving arm 45. When the driving member is rotated as a unit with the switch spindle 30, the arm 45 pressing against one end or the other of the spring 36 tends to carry the lug 55 and its disc along with it.

In order to hold the driven disc 50 against movement until the spring has been sufiiciently stressed to cause snapping action, and also until the spindle has moved sufficiently to cause opening or initial separation of the fixed and movable contacts, there are provided a pair of spaced pivotally-mounted stamped sheet-metal latch arms or levers 61 and 60. These levers are mounted upon the mounting plate 18 by pivot pins, 66and 67 respectively located adjacent opposite edges of the. mounting plate, each pin passing through an end of a lever. Formedv on the opposite end of each leverare noses 62 and 63 respectively which are adapted to engage in notches 53 and 54 formed in the periphery of. the driven member 50. The notches are spaced apart around the periphery so that the nose 62 will enter into the notch 53 in the open position of the switch while the nose 63 will enter into the notch 54 in the closed position. For biasingthe noses against the periphery of the driven disc 50, a coiled tension spring 68 is stretched between the latch levers 6t) and 61, its ends being connected to lugs struck up out of the surface of each of the latch arms. In order to cause the noses 62 and 63 to disengage from the notches 53 and 54 respectively, a portion of each of the levers is bent out of the plane thereof into the plane of the inner driving disc 40. These portions 64 and 65 respectively are adapted to function as cam followers, for camming portions 41 and 42 formed upon the driving disc 44). The cam portions 41 and 42 are radial enlargements spaced apart and lying upon opposite sides of the securing arm 44 in position so that when the driving disc has been rotated a predetermined distance, the cam portion 41 will engage the follower portion 64' of the lever 66 or the cam portion 42 will engage the follower portion 65 of the latch lever 61. After such engagement, continued rotation of the driving disc 40 will cause the nose of the latching lever toleave thenotch in thedriven disc50. At

that time the arms 36a and 36b of the snapping spring 36 will have moved apart due to the movement of the arm 45 while the arm 55 remains stationary. Thus as soon as the nose is disengaged from the notch, the driven member will be snapped, by force of the snap spring, from the position it had previously occupied into the new position, i. e., from the position of Fig. 4 to the position of Fig. 8 or vice versa.

As the switch spindle is rotated in switch-opening direction, its initial movement is transmitted to the slide 70 by engagement of the radial pin 31 extending therefrom with the shoulder 76 of the slide. Assuming that the parts are on the positions of Figs. 4- and 5, the operation may be observed by referring to Figs. 6 and 7 in comparison to Figs. 4 and 5. In Figs. 6 and 7 the spindle has rotated about 15 or 20 degrees and the pin 31 now has come into engagement with the shoulder 76. During the next few degrees of movement of the spindle, the pin causes the slide to move from the dotted position to the full line position of Fig. 7, that is to move longitudinally approximately from the dotted line 0-0 to the dotted line dd. This movement of the slide is transmitted by its lug 71 to the contact carrier 20 which in turn causes the bridging contacts to slowly separate from the fixed contacts a very small distance. This slow initial separation of the contacts as will readily be understood by those familiar with switch operation is effective in suppressing arcs incipient upon contact separation.

After that slow initial movement, continued rotation of switch spindle 30 will cause engagement of the cam 42 with the follower portion 65 of the latch lever 61. As this cam continues to press against the follower portion 65, the latch lever has its nose 63 forced out of the notch 54 with the result that the driven member 50 is snapped from the position of Fig. 4 to the position of Fig. 6.

During the rotation of the switch spindle from the position of Fig. 5 to the position of Fig. 7, the actuating finger 59 on the driven member 50 remains stationary but the slide is moved to the full line position of Fig. 7. As a result, the spring 75 is compressed as will be observed in Fig. 7 during the initial slow opening movement of the slide 70. After the cam 42 engages the follower portion 65 of the latch lever 61 and causes the nose 63 to move out of the slot 54 of the driven member, the driven member is then free to move, which it does with a snap action under the force of a spring 36. This snap movement causes the actuating finger 59 to move from the position of Fig. 7 to the position of Fig. 9 permitting the spring 75 to expand. The snapping action is accomplished by the movement of the actuating finger 59. In moving from the position of Figs. 5 and 7 to the position of Fig. 9, it strikes against the end of the slot 74, thus causes the slide 70 to move with a snap motion. The snapping is particularly etfective because at the time that the finger 59 strikes the end of the opening 74, the finger is moving at a high rate of speed. The hair-pin spring 72 is provided mainly for moving the slide to open circuit position in case the snapping spring for any reason should break or become disabled. The hair-pin spring is free to move the slide whenever the nose 63 is disengaged from notch 54.

The springs 28 press against the movable contact members holding them in resilient engagement with the pairs of fixed contacts when the contact carrier is in closed circuit position. Those springs react however to tend to move the contact carrier from closed circuit position. Hence the combined pressure of the contact springs must be overcome by the pressure of a slides coil spring 72 through which the effect of the position of the snapping is transmitted to the slide and contact carrier. It is therefore necessary for the spring. 75.to be stronger than the combined forces of the contact. springs. I

From the foregoing it will be apparent that I have provided a novel structural combination of parts for electric switch particularly useful as a disconnect switch which is operable from the front but which is not limited to use as a disconnect switch. The structure provides for movement of the bridging contact by a carrier which moves to and fro, or in a straight line, to cause engagement with or disengagement from a pair of stationary contacts; moreover the movement of the bridging contact in opening direction is initially with a slow motion to cause a slow break which is followed by movement of the contacts in the same direction at a more rapid motion with a snap action. The slow break is under control of the operator to the extent that if he moves the handle slowly, he can control the slow-breaking action. But, if he moves the handle as is usually the case with a uniform and continuous motion until the snapping action takes place, the slow break will nevertheless be brought about in the desired manner.

Modifications within the scope of the invention will occur to those skilled in the art. Therefore the invention is not limited to the specific form illustrated and described.

What is claimed is:

1. In an electric switch, fixed and movable contacts, a movable contact carrier, manual operating means, means moving with the manual operating means to positively move said carrier causing slow separation of the movable from the fixed contacts, snap-action means operable by said manual operating means and becoming effective automatically on continued movement of said manual operating means after said slow separation then to continue movement of said carrier in the same direction with a snap motion, and means causing said carrier to move with a snap action uninterruptedly on reverse operation of said manual operating means.

2. In an electric switch, fixed contacts and movable contacts, a contact actuating slide member for moving said contacts rectilinearly into and out of engagement, and means to cause said disengagement initially with a slow motion and then to continue with a snap motion in the same direction comprising a rotary shaft, and snap acting mechanism, means on said shaft positively operating said slide in contact separating direction, and means between said slide member and snap-mechanism to cause the latter to become effective only after contact separatron.

3. In an electric switch, fixed and movable contacts, an actuator movable in an undeviating path to and fro for moving said movable contacts, a shaft, means on said shaft and moving therewith and engaging said actuator when said shaft moves in one direction to cause slow separation of said fixed and movable contacts, and other means operable by the shaft after predetermined rotation and when said contacts are separated to complete the movement of said actuator with a snap motion.

4. In an electric switch as claimed in claim 3 having means holding said other means stationary during the slow separation of said contacts.

5. In an electric switch as claimed in claim 3 having means turning with said shaft to disable said holding means after said slow separation of the contacts.

6. In an electric switch as claimed in claim 3 having an extension on said other means having a resilient lost motion connection with said actuator permitting movement into contact separating direction of said actuator while said other means remains stationary.

7. A switch as claimed in claim 4 wherein the holding means comprises a pivoted latch arm engageable with said other means.

8. In an electric switch, fixed and movable contacts, a slidable actuating member for moving said movable contact, rotary snap acting mechanism, a spindle independent of said actuating member, means to transmit the action of said snapping mechanism to said movable contact, and means operated by said spindle to cause movement of said slidable member slowly to separate said contacts before said snapping mechanism becomes effective.

9. A switch as claimed in claim 8 wherein the snap action mechanism has latching means which is normally engaged in both at-rest positions of the switch, and means to trip said latching means after a predetermined degree of rotation of the snapping mechanism.

10. In an electric switch, fixed and movable contacts, a slidable actuating member for moving said movable contact, rotary snap acting mechanism, a spindle independent of said actuating member, means to transmit the action of said snapping mechanism to said movable contact, and means operated by said spindle to cause slow movement of said slidable member independently of said snapping mechanism, and means operated by rotation of said spindle to cause said snapping mechanism to act after the contacts have separated.

11. In an electric switch, fixed and movable contacts, a slidable actuating member for moving said movable contact, rotary snap acting mechanism, a spindle independent of said actuating member, means to transmit the action of said snapping mechanism to said movable contact, and a member moving unitarily with said spindle to cause slow movement of said slidable member independently of said snapping mechanism, said means to transmit the snap action including a lost motion connection permitting separation of the contacts before said snapping mechanism becomes effective.

12. In an electric switch, fixed and movable contacts, a slidable actuating member, driven means to move said slidable member, snap action means to drive said driven member, a spindle to operate said snap action means, means turning with said spindle to move said actuating member and separate said contacts slowly before said snap acting means becomes effective, and means turning with said spindle to positively move said driven means if said snapping mechanism becomes disabled.

13. An electric switch as claimed in claim 12 having latching means to delay action of said snapping means until said spindle has rotated a predetermined distance, and means rotating with said spindle to release said latching means upon said predetermined rotation of the spindle.

References Cited in the file of this patent UNITED STATES PATENTS 1,354,758 Kellner Oct. 5, 1920 2,068,713 Schellenger Ian. 26, 1937 2,163,919 Siegel June 27, 1939 2,625,619 Rigert Jan. 13, 1953 FOREIGN PATENTS 499,496 Great Britain Jan. 24, 1939

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