US2832860A

US2832860A - Disconnect mechanism

Info

Publication number: US2832860A
Application number: US602245A
Authority: US
Inventors: Lynn H Matthias
Original assignee: Allen Bradley Co LLC
Current assignee: Allen Bradley Co LLC
Priority date: 1956-08-06
Filing date: 1956-08-06
Publication date: 1958-04-29
Anticipated expiration: 1975-04-29

Description

April 29, 1958 L. H. MATTHIAS 2,832,860

DISCONNECT MECHANISM Filed Aug. 6, 1956 4 Sheets-Sheet 1 v INVENTOR ATTORNEY April 29, 1958 H. MATTHIAS 2,832,860

DISCONNECT'MECHANISM Filed Aug. 6, 1956 4 Sheets-Sheet 2 M /K M ATTORNEY April 1958 H. MATTHIAS 2,832,860

DISCONNECT MECHANISM Filed Aug. s, 1956 4 Sheets-Sheet 4 INVENTOR ATTORNEY United States Patent tvcl DISCONNECT MECHANISM Lynn H. Matthias, Fox Point, Wis., assignor to Allen- Bradley Co., Milwaukee, Wis., a corporation of Wisconsin Application August 6, 1956, Seriai No. 692,245

12 Claims. (Cl. 200-(l) gaged with the movable contact means upon closure of I the cover, which handle may occupy three positions comprising an on position wherein the contact means are placed in circuit closing position, on oil position in which the contact means are placed in circuit interrupting position and an open position wherein the contact means are placed in the visual observation position, the invention further providing that in normal operation the cover can neither be closed nor opened unless the handle be in open position and the contact means be in the visual observation position.

Disconnect switches are commonly placed between power lines and motors and motor controls, to provide a means for disconnecting the motor and controls from the line. As such, disconnect switches are manually operated, and are usually left in a circuit closing position unless inspection or service work upon the apparatus powered through the switch is to be performed. At such times the disconnect switch is opened, and reliance is thus placed upon the disconnect to render the equipment to be serviced harmless and free of line voltage.

Occasions arise where overload currents cause the dis connect contacts to weld, and a manual operation of the disconnect actuating handle is not accompanied by a circuit interruption. Since disconnect contacts are usually housed within arc extinguishing chambers, personnel may be unaware of any malfunction, and may then be dangerously exposed to line voltages. It is an object of this invention to have a contact position in which contact condition may readily be observed, after the actuating handle has been moved for circuit interruption, to permit a person to assure himself of the circuit condition. In this manner the disconnect switch more fully plays its function as a safety switch in the circuit.

It is another object of this invention to provide a disconnect switch having an arc extinguishing chamber for the contacts wherein circuit interruption is accomplished with the contacts being housed within the chamber and wherein contacts may be removed from the chamber after circuit interruption to permit visual inspection.

It is another object of this invention to provide an actuating handle on the exterior of a housing for a disconnect wherein both the handle and the disconnect contacts have three normal positions of rest, one of the positions placing the disconnect contacts beyond circuit interrupting position for visual observation.

'ice

It is another object of this invention to provide a disconnect switch With an enclosure wherein the enclosure may normally be opened or closed only when the switch contacts are in a position beyond circuit interrupting position.

It is another object of this invention to provide a disconnect switch having additional safety features to give greater protection to personnel.

It is another object of this invention to provide a disconnect switch in which a pivotal movement of an actuating handle effects a linear movement of an intermediate member to operate the switch contacts with a smooth operation minimizing wear of contacts.

The foregoing and other objects and advantages of this invention will appear from the description to follow. In the description reference is made to the accompanying drawings, which form a part hereof, and in which there is shown by way of illustration and not of limitation a specific form in which the invention may be embodied.

in the drawings:

Fig. l is a front view in elevation with parts broken away of a disconnect and enclosure embodying this inven tion,

Fig. 2 is a side view in elevation with parts broken away of the disconnect and enclosure shown in Fig. 1,

Fig. 3 is a fragmentary view of actuating apparatus on the interior side of the cover of the enclosure viewed from the rear,

Fig. 4 is a fragmentary view of the cover and elements mounted thereon taken on the plane 44 indicated in Fig. 1,

Fig. 5 is a front view of a hub on the front of the cover for supporting the actuating handle, with the nave of the handle removed,

Fig. 6 is a front view in elevation with parts broken away of the contact assembly mounted within the enclosure.

Fig. 7 is a view in section of the contact assembly taken on the plane 7-7 indicated in Fig. 6,

Fig. 8 is a View of contact actuating elements taken on the plane 8-S indicated in Fig. 6, and

Fig. 9 is a view of the elements shown in Fig. 8 in a position differing from that of Fig. 8.

Referring now to the drawings, there is shown in Figs. 1 and 2 a cabinet 1 that comprises a shell 2 open at the front and a cover 3 hinged to the shell so that it may be swung between open and closed positions. Suitable screws 4 are provided on the cover 3 for securing the cover 3 in its closed position. The cabinet 1 encloses three distinct circuit elements. Mounted in the top or" the shell 2 is a disconnect switch 5, intended for connection to power lines introduced within the cabinet 1. Beneath the disconnect 5 is a fuse block 6, and beneath the block 6 is an electromagnetic switch 7. The combination of the

elements

5, 6 and 7 is commonly employed in the control of an electric motor, for a machine tool or other form of power apparatus, requiring frequent switching of themetor. The fuse block 6 and electromagnetic switch 7 are shown in dotted lines as they do not play a part of this invention and are included in the description by way of illustration of one form of apparatus in connection with the disconnect of this invention may be employed.

On the outer face of the cover 3 is mounted a hub 8, more clearly shown in Figs. 4 and 5, that has an open center and which is secured in place by a set of three mounting screws 9 threadedly received by the cover 3. A spacer washer it) and position indicating plate 11 are held between the hub 3 and cover 3. As indicated in Fig. 1 the plate 11 carries the markings designated C011,! fi6ofii,$ locki iopen.7! I

A central boss 12 at the rear of the hub 8 extends eral side of the hub 8 is a plurality of inclined grooves 13. As shown in Figs. 4 and 5, one of the grooves 13 is out directly rearward to partially encircle a pivot post 14 that has a head end visible from the front of the cabinet 1, and which extends through the spacer washer 10, the position indicating plate 11 and the cover 3 to the interior of thecabinet 1. The outwardly facing head end of the pivot post 14 is provided with a slot so that it maybe pivoted by a screw driver or similar instrument. As is also shown in Figs. 4 and 5, a thin flat ring 15 may be inserted in a complementary groove 16 in the front face of the hub 8. The ring 15 is provided with a pair of radially extending ears 17 that cover a pair of the slanting grooves 13. The purpose of this construction will be more fully explained hereinafter.

Mounted upon the hub 8 is an actuating handle 18 having a nave 19 covering the hub 8, from which depends a shank 20 formed to be grasped by the hand. integrally formed with the actuating handle 18 is a stub shaft 21, shown in Figs. 4 and 5, that is extended through the open center of the hub 8 to within the interior of the cabinet 1. The nave 19 is provided on its face with three slotlike openings 22 located to form extensions of the grooves 13 of the hub '8, upon placement of the handle 18 in a position of alignment. The nave 19 is also formed with three recesses 23 in its side, that correspond with the openings 22 to provide three sets of openings and recesses. The recesses 23 also form continuations of the slanting grooves 13, so that upon placement of the handle 18 in a position aligning an opening 22 and its corresponding recess 23 with a groove 13 there will be provided a passage through which the shank of a. padlock may be passed, for the purpose of locking the handle in fixed position. In the illustration of the invention the handle may be placed in the position identified as lock on the position indicating plate 11, for alignment of the three sets of openings 22 and recesses 23 with the slanting grooves 13. Thus, there is provision for securingthe handle .with three separate padlocks, as is a commonly observed'practice in the manufacture of disconnects. If the handle be moved to the 011" position two sets of the openings 22 and recesses 23 will align with a pair of the slanting grooves 13. If the ring 15 be in place these particular grooves 13 will be masked, to preclude insertion of padlocks. However, if it is desired to permit locking of the handle in the on position the ring 15 may be removed, through a partial disassembly. Upon placement of the handle 18 in the on position the third set of openings 22 and recesses 23 aligns 1 with the pivot post 14, to allow a screw driver to be engaged with the pivot post 14, for a purposeto be described.

The inner end of the stub shaft 21 has a rectangularlike end boss 26, shown in dotted lines in Figs. 3 and 5, and an arm 25 fits over the end boss 26 for rotation therewith. The arm 25 narrows as it extends radially outward, and at the end there are formed two spaced turned ears that extend rearwardly, when the cover 3 is closed. A shallow circular neck piece 28 including a pair of spaced circular flanges 29 is fixed on the arm 25 in a position concentric with the axis of the stub shaft 21. A bolt 24, threadedly received by the inner end of the shaft 21, retains the arm 25 and neck piece 23 in place. A spring washer 27 is inserted between the inner face of the cover 3 and the arm 25.

A plate 31 having an arcuate slot 32 encircles the shallow neck 28 of the arm 25 and has a close fit between the flanges 29, that form a part of the neck piece 28. The plate 31 extends to both sides of the slot 32, and spaced close to the slot 32 is a generally horizontal slot 33 in which the ears 3! of the arm 25 are received. The side of the plate 31, opposite that in which the slot 33 is located, tapers and terminates with a recess 34. The recess 34 fits about a fixed pin 35 secured to, the inside of the cover 3. The pin 35 acts as a pivot point for the plate 31, so that upon a rotation of the actuating handle 18 the coupled arm 25 will swing the cars 36 to impart a rotational movement to the plate 31 about the pin 35. Also, the curvature of the slot 32 is selected so that its interaction with the neck piece 23 causes a generally horizontal sliding movement of the plate 31, in addition to the swinging movement about the pin 35. This dual movement causes the end 36 of the plate 31, which is opposite the end of the recess 34, to have a compound movement. The end 36 of the plate 31 is provided with two spaced rearwardly extending ears 37 with a gap 38 therebetween. A pin 39 riveted to one of the upstanding ears 37 completes the plate 31. The compound movement of the plate 31 causes a pronounced vertical travel at the end 36 with a minimum or horizontal shift. The apparatus is dimensioned so that this vertical travel at the center of the gap 38 assumes nearly a straight line upon pivot of the actuating handle 13.

A member 40, formed of fiat stock, is attached on the inside of the cover 3 to the pivot post 14. The member 43 comprises a leg portion 41, attached at one end to the post 14 by a screw 44 as shown in Fig. 3, which widens from the leg 41 and is then turned rcarwardly to form a flange 42 at the opposite end. The flange 42 is turned at its rear edge to present a blocking lip 43 of substantial vertical extent. The member 43 is free to pivot with the pivot post 14- and a bias spring #35 urges the member 49 upwardly against a stop 46, standing inwardly from the cover 3. By means of rotation of the pivot post Ed the member may be rotated downwardly against the spring 45 to place the blocking lip 43 in the position shown in phantom in Fig. 3.

Referring now in particular to Figs. 6 and 7, the disconnect 5 is provided with a pair of left side and right side base brackets 47 and mounted at the back of the shell 2. A set of mounting bolts 49 pass through and secure a molded terminal block 5% to the

base brackets

47, 48. The terminal block 5% is formed with thr e contact receiving cavities 51, and in each of the cavities 51 is disposed a pair of stationary contacts 52 secured to terminal strips 53 leading outwardly from the cavities 51 to terminate in exposed ends carrying terminal screws 54. The terminal strips 53 are clearly shown in Figs. 6 and 7. Along the rear of the block 59 and behind each of the cavities 51 extends a cross bar 56 molded insulating material which has three integral legs 55. Each leg 55 runs forwardly through an opening in the block 5-) into a cavity 51, and a thin metallic finger .59 extends from each leg 55. A bridging contact 57 and a contact spring 5 3 is mounted upon each leg 55, by being passed over the associated finger 59. Caps 6%) hold the springs 53 and bridging contacts 5'. in place. The cross bar 56 has a fore and aft path of movement that carries the contacts 57 into and outwardly from the respective cavities 51, and as may be observed from Fig. 7 each cavity 51 is open at thefront side, opposite the stationary contacts 52, to permit entry and exit of the contacts 51. Thus, the bridging contacts 57 may occupy three distinct positions, the first being a position of engagement with the stationary contacts 52 for closing a circuit, the second being a circuit interrupting position spaced from the stationary contacts 52, but within the cavities 51, and the third being beyond the circuit interrupting position to a position outside the terminal block 50, as shown in 'Figs. 2 and 7, whereby visual observation of contact position may be readily made.

The terminal block is molded from a material se lected for its. arc quenching charactreistics, and for interrupting the arc upon opening the circuit the bridging contacts 57 are retained within the cavities 51. Maximum advantage is thus taken of the are extinguishing ability of the material of the terminal block 50, and the cavities 51 may be termed arc extinguishing chambers. The circuit interrupting position, wherein the movable contacts are retained within the cavities 51, is shown in'phantom in Fig. 7. Upon occasion, however, the movable contacts of a disconnect become welded to the stationary contacts, and do not separate to open the circuit. Personnel are then exposed to line voltages upon entering the cabinet, or working upon the circuit serviced through the disconnect. It is a purpose of this invention to insure protection of personnel by providing a position for the movable contacts in which they may be visually observed upon opening. the cabinet, to permit positive identification of the contact condition. This has not been possible in constructions burying the contacts within arc extinguishing chambers. To accomplish the foregoing purpose the cavities 51 are open ended, as has been described, and introduction of a readily observable contact position beyond the circuit interrupting position is introduced.

To operate the movable contacts 57 the cross bar 56 is mounted upon a rod 61 carried by a pair of supporting levers 62 pivoted to a shaft 63 extending between the

base brackets

47, 48. One end of the rod 61 is attached to an index plate 64 pivoted upon an end of the shaft 63. The index plate 64 has a set of three

detents

65, 66 and 67 clearly illustrated with reference to Figs. 8 and 9. A roller 68 is mounted on a flange shaped arm 69 that rotates about a shaft 70, secured by and extending between the

base brackets

47, 48. The roller 68 rides on the index plate 64 for engagement with the detents 65-67. A wound torsion spring 71 encircles the shaft 76, and has one end fixed by engagement with the bracket 48 with the other end acting upon the arm 69 to firmly seat the roller 68 in a detent 65-67. The index plate 64 is thus held in one of three positions, depending upon the particular detent 65-67 brought beneath the roller 68.

As the index plate 64 is pivoted about the shaft 63, to move one of the detents 65-67 from beneath the roller 68 and to bring another detent 65-67 into position for engagement by the roller 68, the rod 61 is moved forwardly and rearwardly to impart movement to the cross bar 56, and hence to the bridging contacts 57. When the roller 68 rests within the detent 65 the bridging contacts 57 are moved into circuit closing position, in which they engage the stationary contacts 52. When the index plate 64 is rotated to bring the detent 66 into engagement with the roller 68 the bridging contacts 57 are moved to the circuit interrupting position, in which they are still housed within the arc extinguishing chambers formed by the cavities 5'1. Upon movement of the index plate 64 into the position in which the etent 67 is engaged by the roller 68 the bridging contacts 57 are moved tothe visual inspection position shown in Figs. 2 and 7.

An operating lever 72, formed from fiat stock, is pivotally mounted on the shaft 63 immediately adjacent the index plate 64. The lever 72 has a head portion 73 presenting a forward edge 74, and secured to the head portion 73 is a roller 75 adapted to fit within the gap 38 formed by the spacing of the ears 37 on the end 36 of the plate 31. A Window 76 is cut in the operating lever 72 and a similar adjacent window 77 is formed in the index plate 64. A compression spring 73 is inserted within the two

windows

76, 77, so that upon a movement of the operating lever 72 the compression spring 78 will be loaded in compression to urge the index plate 64 to follow the movement of the operating lever 72. The operating lever 72 is further formed with a pry 79, shownv in Figs. 6, 8 and 9, disposed to engage the roller 68 and lift it out of a detent 66-67 when the lever 72 is moved to shift the bridging contacts 57 into or away from the visual observation position. To complete the structure a pin it stands out from the side of the index plate 64 in the path of the operating lever 72, and abutment edges 81 and 82 are provided on the operating lever 72 to strike the pin 80, for moving the index plate 64 with the operating lever 72, after loading of the spring 78, as will hereinafter be discussed.-

To close the cover 3, when it is open, the actuating handle 18 must be moved to its open position, and the operating lever 72, of the disconnect 5, must be moved to its lowermost position, corresponding to the visual observation position of the bridging contacts 57, in which the detent 67 is engaged by the roller 68. Upon closure of the cover 3 the roller 75, of the lever 72, is received within the gap 38 of the plate 31. If the actuating handle 18 be in a position other than its open position, the pin 39 on the end 36 of the plate 31 will strike the forward edge 74 of the head portion 73 of the operating lever 72, thereby precluding full closure of the cover 3. If the operating lever 72 be in a position other than the one of engagement of the detent 67 with the roller 68 the roller '75 will be struck by the blocking lip 43 on the member 46, again precluding full closure of the cover 3. T has, the cover 3 may be closed only when the bridging contacts 57 of the disconnect 5 are in the visual observation position, insuring that line voltages may not be applied to apparatus serviced through the disconnect 5, until the cover 3 is fully closed.

With the cover 3 closed, the actuating handle 18 may be moved to its off position. This causes an upward movement of the end 36 of the plate 31, whereby the roller 75 of the operating lever 72 is likewise carried upwardly. As the operating lever '72 is moved the pry 7%, which at this point in the operation is immediately adjacent the underside of the roller 63 as shown in Fig. 6, moves the roller 63 out of the detent 67. The coupling of the index plate 66 with the operating lever 72, through the compression spring 78, causes the index plate 64 to rotate with the lever 72 and bring the detent 66 beneath the roller The pry 79 passes to the rear of the roller 63, and the wound torsion spring 71 will then move the roller 63 into en agement with the detent 66 with a snap action. The index plate 64 is now held in the position in which the bridging contacts 57 are in the circuit interrupting position, spaced from the stationary contacts 52, but within the cavities 51. This position is shown in phantom in Fig. 7. r

If the actuating handle lid now be moved to its on position the bridging contacts 57 will be brought into engagement with the stationary contacts 5'2. The movement of the operating lever '72, occasioned by movement of the handle i8, loads the compression spring 78, since the roller 68 inhibits the index plate 64 from following the initial movement of the operating lever 72. Upon loading the compression spring 76 the abutment edge 31 of the operating lever 72 strikes the pin 81?, to carry the index plate 64 with the operating lever 72 and raise the rolier 63 out of the detent 66. In Fig. 9 the elements are shown at the point of operation where the index plate 64 has been moved to raise the roller 68. At this point the loaded compression spring 78 abruptly moves the index plate 64 and imparts a rapid circuit closing movement to the contacts 57. The detent 65 is moved beneath the roller 6%, and the wound torsion spring 71 then drives the roller 63 into engagement with the detent 65 to firmly retain the index plate 66in position.

In moving the actuating handle 18 in the reverse direction, that is from its on position through the off to the open position, the bridging contacts 57 will be moved in reverse sequence, from circuit closed position to circuit interrupting position and then to the visual inspection position. The movement of the bridging contacts 57 from the circuit closed position to the circuit interrupting position is accomplished by an initial loading of the compression spring '78, followed by the abutment edge 32 striking the pin 89 and then a movement of the index plate 64 to raise the roller 68 from the detent 65. The loaded spring 76 causes a rapid contact separation and the roller 68 engages the detent 66 to hold the contacts 57 from the stationary contacts 52, but within the arc extinguishing cavities 51.

Uponreturning the bridging contacts 57 to the visual inspection position the pry 7? is again brought into operation. The pry 79 is adjacent the roller 68, as shown in Fig. 8, and movement of the lever 72, in response to the actuating handle 18 being moved to open" position. carries the pry 79 against the roller 68. The roller (58 is raised out of the detent 66, and the compression spring 78 will, without being fully loaded, cause the index plate 64 to follow the lever 72. The detent 67 is then engaged by the roller 68 and the bridging contacts are moved into a visual inspection position whereby they may be readily observed, upon opening the cover 3, to determine that the circuit is open. The pry 79 is utiiized when the bridging contacts 57 are moved into or out of the visual inspection position. For these movements of the bridging contacts 57 rapid snap action, necessary during switching, is not required, and hence full loading of the compression spring '78 is dispensed with.

It should be observed that movement of the open-ding lever 72 away from the position ccrresponi visual inspection position of the bridging cont ries the roller '75 upwardly in front of the blocking lip 43 of the member 4%. Opening of the cover 3 is then precluded, since the blocking lip 4-3 will strike the roller 75. Provision, however, is made to permit opening of the cover 3 when the bridging contacts 57 are in circuit closing position by informed personnel particularly acquaintcd with the construction of the apparatus. When the handle 18 is in on position a screw driver may be engaged with the pivot post 14, and rotated to turn the post 14 and the member 49 to the position shown in phantom in Fig. 3. in this position, the blocking lip 43 is moved from behind the roller 75, to free the cover 3. Special service personnel may thereby have access to the interior of the cabinet 1, when the circuit serviced by the disconnect 5 is closed, in the event occasion should arise for such an inspection.

When servicing and repairing equipment connected to power lines through apparatus of the invention, it is often desirable to lock the disconnect 5 in the circuit interrupting position. This is accomplished by movement of me actuating handle 13 to the oii position, and then slightly beyond the off position to bring the openings and recesses 22-23 into alignment with the slanting grooves 13 of the hub 8. Insertion of the shank or a padlock may then be made to secure the cover 3 closed with the disconnect 5 in circuit interrupting position. As has been heretofore noted provision is made for three such padlocks. Also, if the ring 15 be removed the handle may be locked in the on position, with the contacts in the circuit closing position.

The invention provides for a disconnect in which the contacts have an additional position beyond a circuit interrupting position in which their physical position may readily be identified. An actuating handle is cooperatively related with the contacts, and a cabinet for the contacts may normally not be entered until both the handle and contacts are moved to positions beyond the positions for circuit interruption.

I claim: I

1. In a disconnect mechanism the combination comprising stationary contact means; movable contact means engageable with and disengageable from said stationary contact means; and indexing operating means in me chanically movable connection with said movable contact means and being adapted to actuate said movable contact means to occupy three index positions including a circuit closing position in engagement with said stationary con tact means, a circuit interrupting position spaced from said stationary contact means, and a visual inspection position beyond the circuit interrupting position.

2. In a disconnect mechanism the combination comprising stationary contact means; movable contact means engageable with and disengagcable from said stationary contact means; and operating means for saidmow able contact means adapted to cause said movable contact means to occupy a circuit closing position in engagement with said stationary contact means, a circuit interrupting position spaced from said stationary contact, and a visualv inspection position beyond the circuit interrupting position, wherein said operating means comprises an index plate cooperatively engaged with said movable contact means for moving the same and having a set of three detents; a retaining member adapted to move into engagement with a detent for retaining the index plate in a fixed position; an operating lever for moving said index plate whereby the detents may be successively moved into engagement with the retaining member to define three index plate positions corresponding to said contact positions; resilient means interposed between said index plate and operating lever whereby movement of the lever loads the resilient means and urges the index plate toward a successive position; abutment means interposed between the index plate and lever to carry the index plate with the lever upon loading the resilient means to initially move the index plate against the retaining member when moving the index plate for causing engagement or disengagement of said stationary and movable contact means; and a pry on said lever that dislodges said retaining member from a detent upon moving the lever to alter the index plate position to or from the position corresponding to visual inspection position of said movable contact means.

3. In a disconnect mechanism the combination com prising stationary contact means; an arc extinguishing chamber disposed about said stationary contact means and having an opening opposite the stationary contact means; movable contact means engageable with and disengageable from said stationary contact means which has a movement extending from within said arc chamber through said opening to the exterior of the arc chamber; and indexing operating means in mechanically movable connection with said movable contact means and being adapted to actuate said movable contact means to occupy three index positions including a circuit closing position in engagement with said stationary contact means, a circuit interrupting position within said are chamber spaced from said stationary contact, and a visual inspection position beyond the circuit interrupting position that is outside said are chamber.

4. In a disconnect mechanism the combination comprising stationary contact means; an arc extinguishing chamber disposed about said stationary contact means and having an opening opposite the stationary contact means; movable contact means engageable with and disengageable from said stationary contact means which has a movement extending from within said are chamher through said opening to the exterior of the arc chamber; and operating means for said movable contact means adapted to cause said movable contact means to occupy a circuit closing position in engagement with said stationary contact means, a circuit interrupting position within said are chamber spaced from said stationary contact, and a visual inspection position beyond the circuit interrupting position that is outside said are chamber wherein said operating means comprises an index plate cooperatively engaged with said movable contact means for moving the same and having a set of three detents; a

ctaining member adapted to move into engagement with a detent for retaining the index plate in a fixed position; an operating lever for moving said index plate whereby the detents may be successively moved into engagement with the retaining member to define three index plate positions corresponding to said contact positions; resilient means interposed between said index plate and operating lever whereby movement of the lever loads the resilient means and urges the index plate toward a successive position; abutment means interposed between the index plate and lever to carry the index plate with the lever upon loading the resilient means to initially move the index plate against the retaining member when moving the index plate for causing engagement or disengagement of said stationary and movable contact means; and a pry on said lever that dislodges said retaining member from a detent upon moving the lever to alter the index plate position to or from the position corresponding to visual inspection position of said movable contact means.

5. In a disconnect mechanism the combination comprising stationary contacts; an arc extinguishing chamber disposed about said stationary contacts having an entrance opposite the stationary contacts; movable contacts engageable with and disengageable from said stationary contacts which have a movement extending through said entrance; indexing operating means in mechanically movable connection with said movable contacts and being adapted to actuate said movable contacts to occupy three index positions including a circuit closing position in engagement with said stationary contacts, a circuit interrupting position within said arc chamber that is spaced from said stationary contacts, and an inspection position outside the entrance of said are chamber; an enclosure with a cover housing said contacts and operating means; an actuating handle on the exterior of said enclosure having an on position, an cit position and an open position, said handle being cooperatively engaged with said indexing operating means to actuate the same whereby handle on position corresponds to circuit closing position for said movable contacts, handle cit position corresponds to circuit interrupting position, and handle open position corresponds to inspection position; and interlock means precluding opening of said cover unless said handle is in open position.

6. A disconnect mechanism in accordance with claim having blocking means precluding full closure of said cover unless said handle is in open position and said indexing operating means is placed to move said movable contact means to said inspection position.

7. In a disconnect mechanism the combination comprising an enclosure having a mounting shell and a cover; a disconnect switch within said mounting shell having stationary contacts and movable contacts, which movable contacts have a closed position with said stationary contacts, an open position spaced from the stationary contacts, and an inspection position beyond the open position; an operating mechanism in mechanically movable connection with said disconnect switch having three positions of index for causing movable contacts to occupy said closed, open and inspection positions, and ineluding an operating lever extending toward said cover; an actuating handle on the outer side of said cover having three positions corresponding to the positions of said movable contacts; and intermediate means on the inner side of said cover cooperatively connected to said handle and engageable with said operating lever when said cover is closed to transmit motion from the handle to the lever.

8. An apparatus in accordance with claim 7 wherein said actuating handle is pivotally mounted on the outer side of said cover with a shaft extending through the cover; and said intermediate means comprises: an arm mounted on said shaft on the inner side of said cover for turning movement with said handle; a guiding neck coaxial with said shaft located 011 the inner side of said cover; a plate having an arcuate slot encircling said neck and extending to both sides of the slot with a lever engaging end at one side; a sliding connection between the end of said arm and said plate; and a stationary pivot it) slideably engaging said plate at the end thereof opposite said lever engaging end.

9. In a disconnect mechanism the combination C0111- prising an enclosure having a mounting shell and a cover; a disconnect switch within said mounting shell having a first set of contacts and a movable set of contacts, which movable contacts have a closed position with said first set of contacts, an open position spaced from the first set of contacts and an inspection position beyond the open position; an arc extinguishing chamber for said contacts surrounding both the first set and the movable contacts when the movable contacts are in open position and receding from a surrounding position of the movable contacts for the inspection position of the movabie contacts; and an operating mechanism for said movable contacts including contact indexing means operatively engaged with said contacts, an actuating handle on the outer side of said cover having an on position, an off position and an open position beyond the OE position, and intermediate means on the inner side of said cover operable by said handle and engageable with said indexing means to move said movable contacts in response to actuating handle movement whereby the contact positions of closed, open and inspection corre spond respectively to on, off and open positions of said handle.

10. An apparatus in accordance with claim 9 having a blocking member within said enclosure attached to said cover and a catch member attached to said intermediate means movable into alignment with the blocking member when said handle is moved to on" or off position thereby blocking opening of said cover, and said catch member being moved from a position of alignment with the blocking member when said handle is moved to open position to permit opening and closing of said cover.

11. In a switch the combination comprising a first contact; a movable contact engageable with and disengageable from said first contact; an index member cooperatively engaged with said movable contact to impart motion thereto which motion is toward and from engagement with said first contact; a retaining member adapted to engage with the index member to define a plurality of determined positions for the index member and hence for the movable contact; an operating lever for moving said index member between said determined position; resilient means interposed between said lever and said index member whereby movement of the lever loads the resilient means thereby urging the index memher to a successive determined position; and abutment means between the lever and the index member adapted to make an initial movement of the index member toward the successive determined position after a loading of the resilient means whereby the resilient means causes completion of movement to such successive determined position.

12. A switch in accordance with claim 11 wherein the lever has a pry that moves the retaining member with respect to the index member to permit movement of the index member with a reduced loading of the resilient means upon moving the index member into one of said determined positions.

References Cited in the file of this patent UNITED STATES PATENTS 2,383,296 Dorfman Aug. 21, 1945 2,504,775 Wood Apr. 18, 1950 2,673,260 Lester et a1. Mar. 23, 1954 2,695,934- Wills Nov. 30, 1954