US2521517A - Electric switch - Google Patents

Description

Sept. 5, 1950 H. E. HELLER ETAL ELECTRIC SWITCH 2 Sheets-Sheet 1 Filed April 16, 1947 Sept- 5, 1950 H. E. HELLER ETAL 2,521,517

ELECTRIC SWITCH Filed April 16, 1947 2 Sheets-Sheet 2 ESAQZ.

Patented Sept. 5, 1 950 Herbert E. Heller, wcst Allis, and Clarence W.

Kuhn, Wauwatosa, Wis., assignorsto Cutler- Hammer, Inc., Milwaukee, Wis., a corporation of Delaware Application April 16, 1947, Serial No. 741,906

6 Claims. (01. 200-82) This invention relates to electric switches. The invention relates more particularly'to switches of the electromagnetically-controlled,

pneumatically-operated type and has amon its objects to provide an improved switch of this type which is exceedingly compact and rugged in construction and highly efficient and reliable in operation.

Another object is to provide a switch of the aforesaid type having a movable contact element which is yieldingly supported upon an associated operating part and also normally held in open position by means of a single spring.

Another object is to provide a switch of the aforesaid type in which the pneumatic operating mechanism and the control mean-s therefor constitutes a. unit which is adapted for mounting upon a supporting panel associated with the switch.

Various other objects and advantages of the invention will hereinafter appear.

The accompanyin drawings illustrate an embodiment of the invention which will now be'described, it bein understood that the embodiment illustrated may be modified in various respects without departing from the spirit and scope of the appended claims.

In the drawings,

Figure 1 is a side view of a switch embodying the invention, the switch being shown in closed position and portions thereof being broken away and shown in section;

Fig. 2 is a front elevational view of the switch shown in Fig. 1;

Fig. 3 is a fragmentary side elevational view illustrating the switch parts shown in Fig, 1 in open position;

Fig. 4 is a sectional view on and Fig. 5 is a sectional view on line 5-5 of Fig. 4.

Referring to Fig. 1, the same illustrates a switch line 4-4 of Fig. 1,

I and an associated operating assembly 2 therefor, I

both of which are mounted upon the front face of an elongated vertically disposed insulating base 3. Switch l is provided with a stationary contact 4 and a cooperating movable contact 5 which is normally held in open position by a spring ii Operating assembly 2 includes a vertically disposed cylinder having an associated piston B which operates upon admission of compressed air into the lower end of said cylinder to move-contact 5 into engagement with its associated stationary contact 4 against the action of spring 6. Operating assembly 2 also includes a control valve unit 9 mounted upon the lower end of cylinder 1 and a magnet II] for operating said valve.

More specifically the switch illustrated is provided with a blowout device of the type disclosed in the patent to T. B. Jochem et al., No. 2,240,654, issued May 6, 1941. Briefly described this blowbracket 23 fixed to base 3. is also provided with a horizontally disposed arm) 24 which extends forwardly from the upper end I bracket 23.

out device includes a pair of stationary arc horns II and I2, the former being mounted upon in sulating panel 3 and having the stationary contact 4 fixed thereto, and the latter being asso- 'ciated with movable contact 5 and being carried by an arc chute l3." Arc chute I3 is detachably secured to panel3 and has a pair of pole pieces l4 secured to opposite'sides thereof which are,

associated with opposite'ends of a blowout coil 1 5. One terminal of blow out coil i5 is connected to are horn H and the opposite terminal thereof is connected by a conductor It to aterminal element l1 mounted adjacent the lower end of base 5.

The operating mechanism for movable contact 5 includes an operating lever l9. and a contact lever 20. Operating lever i9 is provided with a vertically disposed arm 2| havingiitsilowerend pivotally supported upon a pin 22 carried by a of arm 2 I. Contact lever 28 is pivotally supported upon a pin 25 mounted upon the upper end of I arm 2| and said contact lever extends forwardly" over the upper side of arm 24. Contact 5 is fixed to the free end of contact lever 22 and the pivoted end of said contact'lever is provided with a rearwardly extending tail projection 26 and a downwardly extending tail projection 21, the latter being connected by a flexible lead 28 to a terminal element 29 mounted adjacent the lower end of base 3. The front end of contact lever 20 is provided with a stop surface 36 for engagin a stop projection 3! on the upper side of arm 24; tail projection 21 is provided with a stop projection 32 for engaging a stop surface 33 on the rear face of arm 2i and tail projection 26 and bracket 23 are provided with cooperating stop projections 34 and 35.

As hereinbefore stated, contact 5 is normally held in open position by a spring 6 and as shown in Figs. 1' and 3 said spring is held under com-- pression between the tail projection 21 on contact lever 20 and a base portion 35 On bracket 23. As is apparent from Figs. 1 and 3, spring 6 tends to rotate contact. lever 20 in a counterclockwise direction upon its associated pivot pin 25 and also tends to rotate operating lever IS in a clockwise direction upon its associated pivot pin 22. Operating lever I9 is normally held against the action of spring 6 in the angular position shown in Fig. 3 by engagement of its associated stop projection 34 with stop projection 35 on Also contact lever Zli is normally held against the action of spring 6 in the angular position shown in Fig. 3 by engagement of its associated stop projection 32 with the stop surface 33 on arm 2!.

Upon rotation of operating lever 19 in a Said operating lever counterclockwise direction out of the position shown in Fig. 3 contact lever 20 is moved bodily therewith until contact 5 is brought into engagement with its cooperating stationary contact 4. Upon continued rotation of operating lever IS in a counterclockwise direction contact arm 20 is rotated upon its associated pivot pin 25 against the action of spring 6 to yieldingly hold contact 5 in engagement with contact 4 during movement of said operating lever into the position shown in Fig. 1. Upon movement of operating lever l9 into the position shown in Fig. 1 the stop projection 3! on arm 24 engages stop surface 30 on contact arm 20 so that contact 5 is positively held in engagement with contact 4- by the operating force applied to operating lever [9. As is apparent, operating lever 19 and contact lever 20 are both returned to the open position shown in Fig. 3 under the action of spring 6 upon release of said operating lever.

As hereinbefore set forth, the operating assembly 2 for switch 1 includes a vertically disposed cylinder 1 having an associated operating piston 8, a valve unit 9 mounted upon the lower end of said cylinder and a magnet In for operating said valve. Cylinder 1 comprises a metal casting and as shown the same has a pair of supporting arms 38-38 formed on opposite sides thereof which extend rearwardly and are secured to the front face of base 3 -by screws 39. As shown in Fig. 1, cylinder 1 is provided with a straight bore 40 and piston 8 is slidably supported within a bushing 4| mounted in the, upper end of said bore. Piston 8 has a cup washer 42 and an oil retaining washer 43 secured to the lower end thereof, both of which fit snugly within the bore 40 and said piston is biased to move upwardly by a spring 44 held under compression between the lower end of said piston and valve unit 9. Piston 8 has a roller 45 mounted upon the upper end thereof which is held in engagement with an insulated plate 46 mounted on the under side of arm 24 of operating lever I!) under the action of spring 44. As shown in Fig. 1, cylinder 1 is provided with a stop screw 41 which engages within a slot 48 in piston 8 to prevent rotation of the latter;

magnet frame 64 is secured by screws 69 to a support I0 extending between the arms 383l associated with cylinder 1. Armature 58 is pivotally supported upon a pin H mounted upon the front end of upper pole projection 65 and said armature is provided with an upwardly extending tail projection 12 which carries an operating part 13 for valve stem 52. As shown in Fig. 4 operating part 13 is slidably supported within an openingin tail projection 12 and is biased forwardly with respect to said tail projection by a spring 14. Said operating part is normally held in the position shown in Fig. 4 against the action of spring 14 by an associated stop nut 75 which engages the rear face of tail projection 12. Also armature 68 is normally held in the position illustrated by dotted lines in Fig. 1 by a spring 15 which is held under compression between bushing 63 and the front end of operating part 13.

Valve unit 9 is provided with a casing 50 of rectangular shape which is secured to the lower end of cylinder 7 by screws 5|. Said casing is provided with an inlet port 52 and an exhaust port 53, the former port being provided with a ball control valve 54, and the latter with a ball control valve 55. Said casing member is also provided with pasages 56 and 51, the former for supplying compresed air to inlet port 52 from a supply pipe 58 upon opening of valve 54, and the latter for permitting escape of air through exhaust port 53 upon opening of valve 55. Valve 54 is normally held in closed position by a spring 59 and said spring also acts through the medium of a pin 50 to normally hold valve in open position. As shown in Fig. 5, pin 60 extends between the valves 54' and 55 and is slidably supported within an opening 6| in casing 50. Valve 55 has a rearwardly extending operating stem 62 associated therewith which is slidably supported within a threaded bushing 63 mounted within an opening in the rear face of casing 50.

The operating magnet in for valve unit 9 includes a stationary magnet frame 64 having forwardly extending upper and lower pol projections B5 and 66; a magnet winding 61 mounted upon said lower pole projection and a movable armature 68 extending between the front faces of said pole projections. As shown in Fig. 1

The operation of the aforedes'cribed operating assembly will now be more fully set forth. Upon energization of magnet winding 6? armature 68 is moved into the attracted position illustrated by full lines in Fig. 1 and during movement thereof into this position the operating part 13 associated with tail projection 12 is moved forwardly against the action of spring 16 to operate valve stem 62 for opening of inlet port 52 by ball valve 54 and closure of exhaust port 53 by ball valve 55. Compressed air is thus supplied to the lower end of cylinder 1 from supply pipe 58 and piston B is moved upwardly into the position shown in Fig. 1

to efiect closure of switch I against the action of its associated biasing spring 5. with the foregoing it should be noted that upon movement of armature 68 into its attracted position ball valve 55 is' yieldingly held in closed position by the spring '14 associated with oper-= ating part I3.

Upon deenergization of operating winding 51" armature B8 is restored to normal position under the action of spring 16 and ball valves 54 and 55 are restored to the position shown in Fig. 4 under the action of spring 59 to close inlet port 52 and to open exhaust port 53. Spring 6 then acts to move switch I into open position and to also move piston 8 downwardly into normal position against the action of its associated spring 44.

In connection with the foregoing it should be noted that the various parts of switch I and its associated operating assembly 2 can be readily removed and replaced from the front of the switch for inspection or repair. For example, if necessary valve unit 9 can be removed from the under side of cylinder 1 without disturbing the other parts of operating assembly 2 or the entire operating assembly can be removed from panel 3 upon'removal of screws 39. Also upon removal of operating assembly 2 the stop 34 on tail .projection 26 can be released from stop 35 on bracket 23 to permit swinging of the movable switch parts forwardly upon pivot pin 22 from the position shown in Fig. 3 into a position wherein contacts 4 and 5 are exposed for inspection or repair.

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

1. The combination with a vertically disposed insulating support, of a control switch mounted upon the front side of said support and having an operating member extending forwardly with respect thereto, said operating member being biased to move downwardly into a given extreme tion for closure of said switch, and a pneumatic In connection 5 i operating unit for said switch mounted upon the front side of said support, said control switch and said operating unit being electrically isolated from each other and said operating unit including a stationary cylinder, a piston operative therein to abut said operating member for up- .ward movement thereof against its bias into switch closing position, and a spring associated with said piston for yieldingly maintaining the same in engagement with said operating memher.

2. The combination with a vertically insulating support, of a control switch mounted upon the front side of said support andv having an operating member extending forwardly with respect thereto, said operating member being biased to move downwardly into a given extreme position for opening of said switch and being movable upwardly againstits bias into an opposite extreme position for closure of said switch, and a pneumatic operating unit for said switch also mounted upon the front side of said support, said control switch and said operating unit being electrically isolated from each other and said operating unit includinga vertically disposed stationary cylinder, a piston operable within said cylinder to move said operating member upwardly against its bias into switch closing position, said piston having an associated roller for engaging the under side of said operating member, and a spring associated with said piston for biasing the same upwardly toyieldingly hold said roller in abutting engagement with said operating member.

3. The combination with a vertically disposed insulating support, of a control switch mounted upon thefront side of said support and having a pivoted operating member extending forwardly with respect thereto, said operating member being biased to move downwardly into a given extreme position for opening of said switch and being movable upwardly into an opposite extreme position for closure of said switch, and a pneumatic operating assembly for said switch also mounted upon the front side of said sup-port, said operating assembly including a vertically disposed cylinder having a supporting bracket associated therewith for mounting upon said support, a piston movable upwardly within said cylinder to move said operating member into switch closing position, a valve unit detachably secured to the lower end of said cylinder and operable to admit compressed air into said cylinder for upward movement of said piston and to vent said cylinder directly to atmosphere to permit return downward movement of said piston for opening of said switch, and a control magnet for said valve unit mounted upon the supporting bracket associated with said cylinder said control switch and said operating assembly being electrically isolated from each other and said operating assembly constituting a unit which is detachable from said support without disturbing the parts of said control switch.

The combination with a vertically disposed insulating support, of a control switch mounted upon the front side of said support and having a pivoted operating member extending forwardly with respect thereto, said operating member being biased to move downwardly into a given extreme position for opening of said switch and being movable upwardly into an opposite extreme position for closureof said switch, a pneumatic operating assembly for said switch mounted disposed upon the front side of said support and including a vertically disposed cylinder having a supporting bracket associated therewith for mounting upon said support, a piston held in abutting engagement with theunder side of said operating member and movable upwardly within said cylinder to move said operating member into switch closing position, a valve unit detachably secured to the lower end of said cylinder and operable to admit compressed air into said cylinder for upward operation of said piston and to vent said cylinder directly to atmosphere to permit return downward movement of said piston and a control magnet for said valve unit mounted upon the supporting bracket associated with said 0371- inder, said control switch and said operating assembly being electrically isolated from each other and said operating assembly constituting a unit which is detachable from said support without disturbing the parts of said control switch.

5. In an electric switch, the combination with a stationary contact and a cooperating movable contact lever, of a movable operating lever having said contact lever pivotally mounted there on, a spring associated with said contact lever and acting to normally hold the same in a given angular position with respect to said operating lever and to also bias said operating lever toward a given normal position for disengagement of said contact lever from said stationary contact, said contact lever when moved into engagement with said stationary contact being movable with respect to said operating lever against the action of said spring to permit overtravel of said operating lever and said operating lever during overtravel being brought into engagement with said contact lever to positively hold the latter in engagement with said stationary contact.

6. In an electric switch, the combination with a stationary contact and a cooperating movable contact lever, of a pivoted operating lever having said contact lever pivotally supported thereon, a spring associated with said contact lever and acting to normally hold the same in. a given angular position with respect to said operating lever and to also bias said operating lever toward a given normal position for disengagement of said contact lever from said stationary contact, a pneumatic operator associated with said operating lever for moving the same out of normal position for engagement of .said contact lever with said stationary contact, said contact lever when moved into engagement with said stationary contact being movable with respect to said operating lever against the action of said spring to permit overtravel of said operating lever, and said operating lever during such .overtravel being brought into engagement with said contact lever to provide for positive engagement of said contact lever with said stationary contact un-' der the action of said pneumatic operator.

HERBERT E. HELLER. CLARENCE W. KUHN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS

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