US2803967A - Operating mechanism for electric switches - Google Patents

Description

1957 T. E. CURTIS ET AL 2,803,967

OPERATING MECHANISM FOR ELECTRIC SWITCHES Filed'April 50, 1953 2 Sheets-Sheet l l NV ENTOR S THOMAS E. CURTIS WILLIAM A. GU SOW ATTORNEY A g 27 T. E. CURTIS ET AL OPERATING MECHANISM FOR ELECTRIC SWITCHES 2 Sheets-Sheet 2 Filed April 30, 1953 llllllllv INVENTORS WILLIAM A.GU SOW ATTORNEY United States Patent Q OPERATING MECHANISM FOR ELECTRIC SWITCHES Thomas E. Curtis and William A. Gussow, Hampton,

Ga., assignors to Southern States Equipment Corporation, a corporation of Georgia Application April 30, 1953, Serial No. 352,098

Claims. (Cl. 74-96) This invention relates to operating mechanisms for electric switches and more particularly to an improved motion-limiting and position-indicating means for use in conjunction with mechanisms adapted for operating high voltage electric switches.

The trend toward higher system voltages and as a result toward larger switch structures also tends to result in the imposition of increasingly heavy loads on the mechanisms which are used to operate such switches. For this reason it is necessary in some switch applications to provide reduction gears for use in conjunction with the switch operating mechanism so that the motivating efior't or power which must be applied to the mechanism is of a lower order of magnitude than would otherwise be required. To this end the travel and operating time of certain parts of the switch operating mechanism must necessarily be increased. Where the travel of parts of the mechanism is greater than with presently known arrangements, and particularly where the paths of travel of parts of the mechanism for a switch opening movement overlap a portion of the paths of travel of such parts for a switch closing movement, ordinary motion-limiting means may bodily obstruct and therefore interfere with movement of the mechanism parts.

A principal object of this invention is to provide an improved switch operating mechanism particularly adapted for use in conjunction with high voltage electric switches. I

Another object of this invention is to provide an improved motion-limiting means which is adapted to accommodate movement of certain parts of the operating mechanism toward the closed position even though such movement overlaps or retraces to an extent the movement of such parts toward the open position. 7

Still another object of this invention is to provide stop means for a switch operating mechanism and in addition to provide indicating means controlled by the stop means for affording a readily observable indication as to a condition of the controlled switch.

The invention in one form as applied to the operating mechanism of an air break or disconnecting switch comprises a stop member mounted on a stationary element of the mechanism or its supporting structure and arranged to move between two extreme positions and having an intermediate position toward which it is biased, a stop engaging member movable with a rotatable element of the mechanism and engageable with the stop member to move the stop member to one extreme position during a switch opening operation and engageable with the stop member to move the stop member to the other extreme position during a switch closing operation, the extreme positions of the stop member being determinative of the open and closed positions of the switch and of its operating mechanism. According to one feature of the invention an indicating device is movable with the stop member so as to afford a readily observable indication as to the condition or position of the switch.

The invention will be better understood from the following detailed description taken in conjunction with the accompanying drawings in which Fig. 1 is a side view of an electric switch and its operating mechanism which embodies the invention; Fig. 2 is a top view of the switch and mechanism shown in Fig. 1; Fig. 3 is an enlarged View of a portion of the operating mechanism shown in Fig. 1 and which embodies the invention; Fig. 4 is a side view partially in section of the structure shown in Fig. 3; Fig. 5 is a view partially in section along the line 55 of Fig. 4 and showing the parts in the closed position; Fig. 6 is a view similar to Fig. 5 showing the parts in the open position, and Fig. 7 is a view along the line 7-7 of Fig. 4 7

showing the parts in the closed position.

With reference to Fig. l the numeral 1 indicates a supporting base structure which could be constructed in the form of a metallic channel member. Mounted on the base 1 are a pair of insulators 2 and 3 which are rigidly afiixed to the base 1 by any suitable known means. Rotatably supported by the base 1 is an insulator stack 4. Aflixed to the upper end of the insulator stack 2 is a yoke element 5 which at its left-hand extremity is formed with a collar element through which the operating rod 6 extends. Yoke element 5 is provided with a hinge pivot 7 about which the switch blade 8 is arranged to swing. Suitable known means to facilitate the interchange of current between yoke 5 and blade 8 should be provided. The right-hand extremity of switch blade 8 cooperates with a pair of jaw contacts 9. Electrically connected with jaw contacts 9 is an electric terminal element 10 which is adapted to form an electric connection with an external circuit controlled by the switch. Similarly an electric terminal 11 is arranged to form an electric connection with another lead of the circuit controlled by the switch. Thus the circuit through the switch comprises terminal 11, yoke 5, blade 8, jaw contacts 9, and terminal 10.

Since the switch is of the twist blade type, an operating mechanism is provided for rotating the blade about its longitudinal axis before imparting swinging movement thereto about the pivot 7 in order to perform an opening operation. To this end the upper extremity of the operating rod 6 is provided with a crank element 12 which is pivoted at 13 to an operating rod 14 which in turn is pivoted at 15 to a connector element 16 rigidly secured to the switch blade 8. While the switch described thus far is schematically represented it will be understood that rotation of the operating rod 6 imparts cranking movement to the crank 12 which in turn imparts rotary movement to the blade 8 about its longitudinal axis and sub-- sequently imparts a swinging movement thereto about the hinge pivot 7 to cause the right-hand extremity of the blade 8 to separate from the jaw contacts 9. The switch described above could be of the type disclosed in Patent 2,545,940 Caldwell granted March 20, 1951, and assigned to the assignee of this invention.

Rotary movement is imparted to the operating rod 6 by means of the crank 17 which is rigidly afiixed to the lower extremity of the rod 6 or its extension. Pivotally connected to the extremities of the arm 17 are the operating rods 18 and 19 which at their left-hand extremities are pivotally connected to the crank arm 20. Crank 21 is secured at its center of rotation to the spindle 21. Mounted on the spindle 21 is the gear 22 which meshes with the pinion 23 secured to the upper end of the shaft extension 24 for the vertical shaft 25. The gears 22 and 23 are enclosed within a housing structure 26, suitable support therefor being provided in known manner. The lower extremity of the operating rod 25 is connected by connector means 27 with the spindle 28 on which the by means of a pinion 30 which is mounted for rotation about a shaft 31 and rotary motion is imparted to pinion 30 by the manually operable crank 32. Gears 29 and 30 are enclosed within the housing structure 33 which in turn is supported by suitable structure not shown. From the description thus far it will be understood that rotation of crank 32 in the clockwise direction for example as indicated by the arrow will impart rotary motion to shaft and to operating rod 6 and thereafter will result in opening of switch blade 8. By the same token rotationof crank 32 in the opposite direction will cause the switch blade 8 to swing in a clockwise direction about the pivot 7 to engage the jaw contacts 9 and thereby to establish a closed circuit through the switch.

It will be observed that the gear 23- is smaller than the gear 22. One suitable ratio would be to construct the gear 23 one-half the size of the gear 22 and to pro vide for a ratio of twelve to one between gear and gear 29 thereby to obtain a desirable mechanical advantage of twenty-four to one which would enable smooth operation of the relatively heavy switch with a relatively small force being required at the handle 32.

For the purpose of affording a travel limiting stop arrangement for the switch and its operating mechanism and also to indicate the position or condition of the switch, the structure generally designated at 3311 is provided in accordance with this invention.

Withreference to Figs. 3 and 4, a movable stop member 34- is disposed to be engaged by a stop engaging member 35 securely affixed to the element 25 by means of adjustable setscrews 36. With the stop engaging member 35 in the desired position relative to rotatable element 25, the screws 36 are simply tightened so that the stop engaging element 35 is movable with the movable element or operating shaft 25. The movable stop 34 is pivotally supported by a vertically disposed shaft 37 which extends through openings formed in the upper plate 38 and the lower plate 381; of the box-like structure having its side walls 42 and 42a bolted through the flanged surfaces 39 and 39a respectively to the fixed element in the form of I-beam 40 by means of bolts 41'. As is best seen in Figs. 5, 6, and 7 the flanges. 39. and 39a respectively constitute an integrally formed portion of the side walls 42 and 42a.

The movable stop 34' is mounted for limited movement with respect to the element comprising top wall 38; bottom wall 38a, and the side walls 42 and 42a, the movable stop 34 being provided with a pair of oppositely disposed projections 43 and 43a which are arranged: to

engage the spaced stops 44 and 44a formed on the sidewalls 42 and' 42a along the inner surface thereof. Thus it will be understood that rotation of the handle 32 in one direction as viewed in Fig. l imparts clockwise rotation to the rotatable element 25 as viewed in Figs.

5 and 6 for example to cause the stop engaging ele-- ment 35 to move into engagement with the left-hand extremity of the movable stop 34 so as to cause the projection 43a thereof to engage the stop 44a on side wall 42a as viewed in Fig. 5 thereby to provide a positive limiting means to prevent further clockwise rotation of movable element 25; Fig. 5 represents one extreme. po-

sition for the movable stop 34. Likewise rotation of crank 32 in the opposite direction imparts counterclockwise rotation to element 25 and causes the stopengaging element 34 to move to the position represented,- by

Fig. 6 wherein the projection 43. of the movable stop 34 engages the, stop 44 to limit opening movement, off

the operatingv mechanism and of the controlled switch. Thus the movable element or operating shaft 25 can rotate through 360 or more and still is? provided with suitable means for positively stopping-the rotation-Ahercof in the extreme limits of travel. It will' be observed from Figs. .4 and 7 that themovable stop 34 is biased toward a midposition between. the walls 42. and. 42a by means of'a pair of coiled, springs 45- and 46,.therup.

per extremity of spring 45 being in engagement with thewall 42a and the lower extremity of the spring 46 being in engagement with the opposite wall 42. The

lower extremity of spring 45 and the upper extremity of spring 46 engage the projecting portion 47 of the movable stop member 34.

From Figs. 4-7 it will be observed than an extension 48 is secured to or formed integrally with the lower wall 38a and that this extension is provided with an opening through which the movable element or operating rod 25 extends. At the left-hand extremity of the extension 48 an arcuate masking element 49 is provided and is secured to the extension 48 by means of the screws 50.

From Figs. 4-7 it will be understood that an indicating element 51 is secured to or formed integrally with the movable stop 34 and as is shown in Fig. 3 the words open and "closed are formed on the indicating element 51 to afford a readily observable indication of the condition of the controlled switch. When the switch.

and, its operating mechanism are in the open position asv represented by Figs. 3, 4, and 6, the word open is readily visible as indicated in Fig. 3 and the word closed is not visible since this portion of the indicating element 51 is disposed: behind the masking element 49 mounted on. the extension 48. Likewise, when the switch and its operating mechanism are in the closed position as is represented by Figs- 5' and 7, the word closed is ob servable and the word open is masked by the element 49 so as. notto. be visible. As. the element 35 is. rotated away from. one extreme position toward the other position the springs. 45 and 46 cooperate. to move the stop 34. and member 51 to a midposition and to maintainthese. parts in. that position until the member 35 approaches, the other position. While in the midposition neither theword. open nor the word closed is visible since. the masking element 49 is arranged to obstruct the view of both words while the stop 34 and member 51 are. in the midposition. Thus the indicator is prevented. from affording apremature indication of the position of the switch.

From the above description it will be understood that a suitable meansfor indicating the position or condition of the controlled switch is provided which is associated withthe movable stop member in the form of the element 34.

If desired, the enclosing structure comprising the top plate. 38;, the. bottom plate 38a, and the side walls 42 and 42a, together with the extension 48 could be formed asa single; integral casting or. if. desired these: parts could be formed. separately and secured in position by suitable welding or other techniques.

While; wehave; shown: and described a particular embodiment of the invention, wedo not wish to be limited thereto and intend in the appended claims to cover all such. changes and? modifications as fall within the true spirit and scope of the invention.

What'we claim as new and desireto secureby' Letters Patent of' the United States is:

1. In a switch operating mechanism, a pair of relatively movable elements, a unitary stop member mounted on one of said elements and'. movable with respect thereto between two. extreme positions, and stop engaging means; movable with the other of said elements and engageable with said. stop member to move said stop member bodily tov one extreme. position in response to relative. movement of. said elements. in one direction thereby to arrest further"relative'movement of said elements in. said one direction, said stopi engaging means: being engageable; with said stop' member to move said stopmember? bodily-torthe other extreme position in re sponse to relativeam'o'vement of said elements in another direction: thereby to. arrest further relative movement of said elements in said another direction, said'other element being movable independently of said stop member dur' ing a substantial portion of its operating movement.

2. In a switch operating mechanism, a pair of relatively movable elements, a unitary pair of spaced stops on one of said elements, a stop member pivotally mounted on said one of said elements between said stops and movable with respect thereto between two extreme posi' tions as determined by said stops, and stop engagingmeans movable with the other of said elements and engageable with said stop member to move said stop mem ber bodily to one extreme position in response to rela tive movement of said elements in one direction thereby to arrest further relative movement of said elements in said one direction, said stop engaging means being engageable with said stop member to move said stop member bodily to the other extreme position in response to relative movement of said elements in another direction thereby to arrest further relative movement of said elements in said another direction, said other element being movable independently of said stop member during a substantial portion of its operating movement.

3. In a switch operating mechanism, a pair of relatively movable elements, a unitary stop member mounted on one of said elements and movable with respect thereto between two extreme positions, stop engaging means movable with the other of said elements and engageable with said stop member to move said stop member to one extreme position in response to relative movement of said elements in one direction thereby to arrest further relative movement of said elements in said one direction, said stop engaging means being engageable with said stop member to move said stop member to the other extreme position in response to relative movement of said elements in another direction thereby to arrest further relative movement of said elements in said another direction, and indicating means movable in coordination with movement of said stop member for indicating a condition of the operating mechanism, said indicating means and said stop member being independent of said other element during a substantial part of the operating movement of said mechanism.

4. In a switch operating mechanism, a pair of relatively movable elements, a unitary stop member mounted on one of said elements and movable with respect thereto between two extreme positions, and stop engaging means mounted on the other of said elements and engageable with said stop member in response to relative movement between said elements, said stop member being movable to one of its extreme positions upon engagement with said stop engaging member in response to relative movement between said elements in one direction thereby to prevent further relative movement between said elements in said one direction, said stop member and said other element being independent of each other during relative movement between said elements in said one direction and before engagement between said stop member and said stop engaging means.

5. In a switch operating mechanism, a pair of relatively movable elements, a unitary stop member mounted on one of said elements and movable with respect thereto between two extreme positions and having a midposition intermediate said extreme positions, stop engaging means mounted on the other of said elements and engageable with said stop member in response to relative movement between said elements, said stop member being movable from its midposition to one of its extreme positions upon engagement with said stop engaging means in response to relative movement between said elements in one direction thereby to prevent further relative movement between said elements in said one direction, and said stop member being movable from its midposition to the other of its extreme positions upon engagement with said stop engaging member in response to relative movement between said elements in another direction thereby to prevent further relative movement between said elements in engagement with said stop engaging member in response said another direction, said stop member and said stop engaging means being independent of each other during an intermediate portion of the relative movement between said elements in each of said directions.

6. In a switch operating mechanism, a pair of relatively movable elements, a unitary stop member mounted on one of said elements and movable with respect thereto between two extreme positions and having a midposition intermediate said extreme positions, stop engaging means mounted on the other of said elements and engageable with said stop member in response to relative movement between said elements, said stop member being movable from its midposition to one of its extreme positions upon to relative movement between said elements in one direction thereby to prevent further relative movement betweensaid elements in said one direction, said stop member and said other element being independent of each other during relative movement between said elements in said one direction and before engagement between said stop member and said stop engaging means, and yieldable means biasing said stop member toward its midposition.

7. In a switch operating mechanism, a pair of relatively movable elements, a unitary stop member mounted on one of said elements and movable with respect thereto between two extreme positions and having a midposition intermediate said extreme positions, stop engaging means mounted on the other of said elements and engageable with said stop member in response to relative movement between said elements, said stop member being movable from its midposition to one of its extreme positions upon engagement with said stop engaging member in response to relative movement between said elements in one direction thereby to prevent further relative movement between said elements in said one direction, and said stop member being movable from its midposition to the other of its extreme positions upon engagement with said stop engaging member in response to relative movement between said elements in another direction thereby to prevent further relative movement between said elements in said another direction, said stop member and said stop engaging means being independent of each other during an intermediate portion of the relative movement between said elements in each of said directions, and indicating means movable in coordination with movement of said stop member for indicating a condition of the operating mechanism.

8. In a switch operating mechanism, a pair of relatively movable elements, a unitary stop member mounted on one of said elements and movable with respect thereto between two extreme positions and having a midposition intermediate said extreme positions, stop engaging means mounted on the other of said elements and engageable with said stop member in response to relative movement between said elements, said stop member being movable from its midposition to one of its extreme positions upon engagement with said stop engaging member in response to relative movement between said elements in one direc tion thereby to prevent further relative movement between said elements in said one direction, and said stop member being movable from its midposition to the other of its extreme positions upon engagement with said stop engaging member in response to relative movement between said elements in another direction thereby to prevent further relative movement between said elements in said another direction, said stop member and said stop engaging means being independent of each other during an intermediate portion of the relative movement between said elements in each of said directions, yieldable biasing means tending to hold said stop member in its midposition, and indicating means movable in coordination with movement of said stop member for indicating a condition of the operating mechanism.

9. In a switch operating mechanism, a fixed element,

a w et bl s z ps a ita sto membe iii t o ens of said lem t i m a l w h s e there? between two extreme positions, stop engaging means mounted on the other of said elements ander igageab1e with said stop member to move said stop membei te bne extreme position in response to rotation of said rotatable element in one direction thereby to arrest fu rther rotation of said rotatable element in said one direction, said stop engaging means beingengageable with saidst op member to move said stop member to the other extreme position in response to rotation of said rotatable element in the opposite direction thereby to arrest further rotation of said rotatable element in saidopposite, direction, and indicating means movable in coordination with moi/ement of said stop lber for indicating a condition of e e tatit Q E f L i i e e" l being ide den O 1M e l asi is sw mmediate portion of the relative movement betwemsaid eiernents in each direction. i i 10. In a switchopera ting mechanism, a pair of relafiviy m c em se were: i m em m 'a on one of said elements and movable with respect thereto between two indieating positions and having an intermediaie pqsition between said indicating positions, and engaging means mounted on the other of said elements and ngageable with said indicating member in response to relative movement between said elements, said 'indicating member being movable from its intermediate position to either of its indicating positions upon engagement with said engaging member, and said indieating member being independent of said engaging means during an intermediate portion of the travel of said engaging means.

References Cited in the file of this patent UMTED STATES PATENTS 1,386,065 Lofton Aug. 2, 1921 2,270,866 Gotesworth Q Jan." 27, 1942 2,542,531 Jefirey Feb. 20, 1 951: 2,648,678 Obe'nqnr Apr 10, I951 2,578,042 Ghandler Dec. 11, 1951 2,656,178 HUghESQQQQ Oct. 20, 1953

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