US2615101A - Sliding bolt rack mechanism - Google Patents

Description

Oct. 21, s QAS SLIDING BOLT RACK MECHANISM Filed Sept. 19, 1950 v 3 Sheets-Sheet l IE Z I N V EN TOR. firm a4 \7. Kama/z Oct. 21, 1952 A. s. CASWELL SLIDING: BOLT RACK MECHANISM 3 Sheets-Sheet 2 Filed Sept. 19, 1950 ICE--15 -riOJ I N V EN TOR. $127M? 5. dam/5a.

BY WJW Oct; 21, 1952 A. s. CASWELL SLIDING BOLT RACK MECHANISM- 3 Shets-Sheet: 3

Fild Sept. 19, 1950 I N V EN TOR flan/w? .5 Unswaz W #921,

Patented Oct. 21, 1952 SLIDING BOLT RACK MECHANISM Arthur S. Caswell, Philadelphia, Pa., assignor to I-T-E Circuit Breaker Company, Philadelphia, Pa., a corporation of Pennsylvania Application September 19, 1959, Serial No. 185,572

9 Claims.

My present invention is an improvement of the racking mechanism disclosed in the circuit breaker described in application Serial No. 721,648, of Joseph D. Wood, filed January 11, 1947, and application Serial No. 757,356, of Elmer Goessel, filed June 7, 1947, and relates specifically to .the means for securing the racking bar to the stationary cubicle in order to provide an appropriate anchor for the racking mechanism.

My present invention is also an improvement of the racking mechanism described in my application Serial No. 159,598, filed May 2, 1950, relating also to an improvement in the means for securing the racking bar to the cubicle.

In the latter application, a grounding device is shown which is intended to be racked into and out of a cubicle to replace a circuit breaker. The grounding device has a racking bar which is movable by a screw thread with respect to the grounding device.

Thus, when the racking bar of the grounding device is anchored in the cubicle, the relative movement of the racking bar with respect to the grounding device causes the grounding device to move in or out of the cubicle owing to the fact that the racking bar is secured to said cubicle.

The specific method of obtaining this anchor is shown in my aforesaid application Serial No. 159,598 as a pair of movable latching means in the cubicle which engage the ends of the racking bar.

In the above-mentioned applications, Serial Nos. 721,648 and 757,356, no specific means is shown for anchoring the end of the racking bar, but locks of the type shown in application Serial No. 159,598 may be used and have, in fact, been used commercially.

The utilization of such additional locks which require manipulations at the side of the cubicle when the circuit breaker or grounding device, as the case may be, is introduced into the cubicle in order to anchor the racking bar with respect to the cubicle creates some difficulty in that the operator must manipulate these locks on opposite sides and does not operate them from the front.

In addition, the utilization of such additional movable anchoring members in'the cubicle requires the placement of such movable parts on the stationary cubicle element and the exact registry of these movable parts with the racking bar.

My invention is, therefore, directed to a novel racking bar having a sliding bolt interlock at each end arranged to engage a flange of the cubicle. The sliding bolt interlock is so arranged 2 that manipulation of a handle at the front of the circuit breaker, the grounding device, or other element which is to be introduced into the cubicle between the locked and unlocked position will cause the sliding bolt to move out to locking engagement behind the flange or in out of locking engagement behind the flange.

In applying my invention to a circuit breaker of the type disclosed in application Serial No. 721,648, the structure of the circuit breaker therein shown and the structure of the racking in mechanism therein shown need not be changed in any manner.

It only requires a change in the transverse racking bar 400 (Figs. 1, 10, 11 and 12) of the mechanism shown in the said application.

By the utilization of my novel racking bar, the circuit breaker mechanism is interlocked with the racking bar so that the circuit breaker cannot be introduced into the cubicle unless the circuit breaker mechanism is in the test position.

After the circuit breaker has been introduced into the cubicle and the racking bar locked with the cubicle, then and only then may the circuit breaker mechanism be racked into the operating position. After the circuit breaker is racked into the operating position, it cannot be pulled out of the cubicle until it is racked out to the test position.

A primary object of my invention, therefore, is the pro-vision of a novel racking bar so arranged as to enable a circuit breaker, grounding device or other similar piece of electrical apparatus to be racked in and out of the test and operating position in a cubicle.

Another object of my invention is the provision of a novel racking bar with a sliding bolt interlocked with a flange or other retaining element in a cubicle.

Another and corollary object of my invention is the provision of a racking-in mechanism which will co-act with an interlocking means in such a manner as to remove necessity of holding adjustments between stationary structure and removable element to close and exact tolerances. Such an interlocking means is described in a pending application, Serial No. 135,573.

Another object of my invention is the provision of a novel means interlocking the racking bar and the racking mechanism in such manner that the circuit breaker cannot be inserted in the cubicle unless it is in the racked out or test posi tion, and it cannot be withdrawn from the cubicle unless it is in the racked out or test position.

The foregoing and many other objects of invention will become apparent in the following description and drawings in which:

Figure 1 is a view in perspective of my novel racking bar showing the same in unlocked position.

Figure 2 is a View corresponding to that of Figure 1 showing the racking bar in the locked position.

Figure 3 is a view in perspective showing the racking bar of my invention mounted on the circuit breaker of application Serial No. 721,648 with the circuit breaker in a position out of the cubicle and with the racking bar in the unlocked position of Figure 1.

Figure 4 is a top plan view partly in cross-section of the racking mechanism of Figures 1 to 3.

Figure 5 is a front view partly in cross-section of the racking mechanism of Figures 1 to 3.

Referring to the figures, the racking bar 400 corresponds in location and actual function to the racking bar 400 shown in Figures 1, 10, 11 and 12 of application Serial No. 721,648.

Since the racking mechanism which is actually used is shown in the heretofore referred application Serial No. 721,648 and is fully described therein, a separate specific description of the racking mechanism which moves the circuit breaker with respect to its support is not contained herein but rather may be regarded as incorporated by reference herein.

While the specific racking bar 400 of the present invention may cooperate with other racking mechanisms, it is preferred that it be used with the racking mechanism of the said application Serial No. 721,648 and with the circuit breaker shown in the said application.

The racking bar 400 forming a part or" the circuit breaker mechanism as shown in the above identified application is provided with an opening l which is provided with internal screw threads which engages the threads of racking screw I I. Racking screw I I is rotatable and such rotation moves the bar 400 along the racking screw II.

Racking bar 400 and screw I I are supported on the circuit breaker by the engagement of screw II with bearing I2 on the circuit breaker mechanism. The outer end I of screw I I is provided with a handle or with a squared end I5 or other deformation which will enable a handle to be attached for the purpose of rotating the screw I I.

Rotation of end I5 of screw II will, of course, cause the screw I I to rotate and to move the bar 400 longitudinally along the screw II in a direction determined by the direction of rotation of screw II. The bearing i2 is a thrust bearing to provide against the longitudinal forces of the screw II.

The movement of the bar 400 along the screw II causes it to move with respect to the breaker.

Should the racking'bar be held stationary, then rotation of screw II causes the screw II and the circuit breaker mechanism mounted therein to be racked in or out of the operating position.

The racking bar 400 is provided with extensions 20 and 2I on each side, the said extensions having the cylindrical openings 22 and 23, respectively, extending parallel to the racking bar 400.

Sliding bolts 24 and 25 are operable in the openings 22 and 23, each of the sliding bolts 24 and 25 being, respectively, mounted on flange 2! and .28 of the slide members 29 and 30 of the racking bar 400. Slide member 29 is slidably positioned on the racking bar 400 by the head 35 of a bolt secured to the racking bar 400 and 4 holding the slide member 23 through the slot 36 between the head 35 and the racking bar 400.

Slide member 30 is also slidably mounted on the racking bar 400 for longitudinal movement with respect thereto by bolt 40 and the rotatable threeway crank 4! having the bifurcated arms 42 and 43 and the handle 44. The material of the slide member 30 defining the slot 50 is captured be tween the three-way crank 45 and the racking bar 400 so as to position the slide member 30 thereon.

Slide member 20 is thus supported parallel to the racking bar 400 and in substantial surface to surface relation therewith by the bolt 35 at one end and slot 36 while at the other end the sliding bolt 24 in the cylindrical opening 22 of extension 20 of the racking bar 400 supports and aligns the slide 29.

Slide 30 is similarly aligned by bolt 42 and slot 50 and by sliding bolt 25 and opening 23. Slide member 29 has extension 00 secured thereto in any suitable manner as by welding, the said extension being provided with a pin 6| captured in the end of bifurcated crank element 43.

Slide member 30 is provided with a pin 63 captured in the bifurcated element 42 of the crank 4|.

It will thus be seen by a comparison of Figures 1 and 2 that when the handle and pointer assembly 04 is moved from the upper or unlocked position to the lower or locked position, the crank member 4| is rotated clockwise and bifurcated section 42 thereof moves the pin 63 and slide 30 to the right, while bifurcated section 43 thereof moves the pin SI, extension 60 and slide 29 to the left.

This, therefore, moves the bolts 25 and 24 on each side outwardly so that they protrude, respectively, from elements or extensions 20 and 2| of the racking bar 400.

It will thus be seen that after a circuit breaker I00 is placed in the cubicle I02, the movement of handle 44 from the unlocked position of Figure 1 to the locked position of Figures 2 and 5 will extend the bolts 24 and 25 out through openings 22 and 23 so that they extend beyond the ends of extensions 20 and 2 I.

The manner in which my novel racking bar is mounted on the circuit breaker I00 is shown in Figure 3.

The racking mechanism 10 corresponds exactly to the racking mechanism shown in Figs. 1, l0, l1 and 12 of application Serial No. 721,648.

The cubicle I02 is provided on each vertical front edge with a vertical flange I03. When the circuit breaker I00 is wheeled into the cubicle I02, it is moved in until the bolts 24 and 25 are so aligned that when extended they will extend just behind the flange I03 on each side.

An additional flange I04 is provided with each side spaced inwardly from flange I 03 and at a location where it will provide a bearing for bolts 24 and 25 on each side.

When the bolts 24 and 25 are extended as shown in Figures 2 and 4, they will thus register in the space between the vertical flange I03 on each side and the additional flange I04 on each side. The vertical flange I03 (Fig, 3), since it is provided in any event for the cubicle, requires no exact registry with the bolts 24 and 25, while the flange I04 may be made sufficiently long so that no problem of registry will arise with respect thereto.

After the circuit breaker I00 is wheeled into the cubicle I02 then the handle 44 is turned from the unlocked position of Figures 1 and 3 to the locked position of Figures 2 and 5 and bolts 24 and 25 are thereby simultaneously moved as previously described beyond the ends of extensions 20 and 2I where they will engage in the space between flanges I03 and I04 on each side.

This serves to anchor the racking bar 400 in a horizontal direction to make it stationary so that when the racking bar 400 is forced to move with respect to the bearing I2 of the circuit breaker I00, then since the racking bar 400 is anchored relative to the cubicle, the circuit breaker element as a whole must move with respect thereto.

By this means, therefore, a simplified anchoring element is provided for th racking bar 400 which does not require hooks or other manipulating devices in the cubicle but requires only the simple manipulation of handle 44 from the unlocked to the locked position and vice versa.

While the circuit breaker and rocking bar 400 is out of its cubicle, it is possibl for some one to turn screw I I and thus change the relative position of the screw with respect to the circuit breaker and cross bar 400.

It is accordingly desirable that additional interlock means be provided so that the circuit breaker I (Fig. 3) cannot be wheeled into the cubicle I02 unless the racking bar 400 and the circuit breaker I00 are in the appropriat position with respect to each other, that is, with the circuit breaker mechanism racked out or to put it another way, with the racking bar 400 at its innermost position with respect to the circuit breaker.

Also, it is desirable, and in fact, an important safety factor, to provide means whereby the racking bar 400 cannot be disengaged from the cubicle I02 to enable a pulling out of the circuit breaker I00 unless the circuit breaker I00 has first been racked out by the use of the racking means so that it is completely disconnected from any back connection studs which are provided between the circuit breaker and the current conducting members leading to the cubicle.

For this purpose, therefore, the circuit breaker is provided with a platform having downwardly depending flanges 200,20I (see Figs. 1, 2, 4 and 5), the lower ends of each flange 200 and I being provided with the slots 202, 203, respectively.

The slide elements 29 and 30 of the racking bar cannot be moved inwardly toward each other to the unlocked position of Fig. 1 unless the circuit breaker I00 and hence its flanges 200 and 20I are racked out to a position where the slots 202 and 203 register opposite to the slide members 23 and 30 as shown in Figure 1.

This is so because the slide members 29 and 30 are arranged, respectively, to intersect the lower margins of the flanges 200 and 201, and, therefore, they cannot move in from the locked position of Figure 2 to the unlocked position of Fig. 1 unless the circuit breaker has been racked out so that the slots 202 and 203 register with the ends of the slides 29 and 30.

Thus, the racking bar cannot be placed in the unlocked position with the bolts 24 and 25 withdrawn as shown in Fig. 1 unless the entire circuit breaker is in a position equivalent co being racked out. correspondingly, if racking screw I I of the circuit breaker is in a position of being racked-in when the circuit breaker itself is outside the cubicle, then the bolts 24 and 25 must be extended.

These bolts will, therefore, engage the outer surfaces of the vertical flanges I03 (Fig. 3) when the circuit breaker is being moved into the cubicle and will prevent the entry of the circuit breaker I00 into the cubicle I02.

Therefore, before the circuit breaker I00 can be introduced in the cubicle I02, the bolts 24 and 25 must be Withdrawn and to accomplish this operation, the circuit breaker must be racked out or the racking bar 400 must be at its full inward position with respect to the circuit breaker I00 which is the equivalent of the racked-out or test position of the circuit breaker I00.

After the circuit breaker I00 has been properly moved into the cubicle I02 with the bolts 24 and 2-5 withdrawn to permit the entry, the racking" mechanism cannot be operated to move the circuit breaker I00 into the operating position until the racking bar 400 has been locked by the moving down of handle 44.

This is so because any attempt to rack in the circuit breaker once it is introduced into the cubicle but not locked will result in relative movement of the racking bar 400 with respect to the circuit breaker element I00 but because of the relatively greater inertia of the circuit breaker I00 the racking bar will be moved by the rotation of the racking screw I I.

Consequently, before the racking-in movement is begun, the handle 44 must be pressed down to extend the bolts 24 and 25 into a recess or aperture mounted on the track (not shown). This serves to lock and anchor the racking bar 400 with respect to the cubicle I02 and at the same time allows the slides 29 and 30 to emerge freely from the slots 202 and 203.

The screw II may now be turned to rack the circuit breaker I00 in from the test position to the operating position. At the initiation of this racking-in movement, the flanges 200 and 20I move inwardly to the rear of the cubicle and hence slots 202 and 203 therein move inwardly toward the rear of the cubicle so that the solid material at the lower end of the margin of flanges EM and 200 is in the path of movement of the slides 29 and 30.

Consequently, the handle 44 cannot be raised to the unlocked position and bolts 24 and 25 cannot be withdrawn from looking position while the circuit breaker is even partially racked-in owing to the fact that the inward movement of slides 29 and 30 is impeded by the lower margin of the flanges 200 and 20! and also owing to the fact that the slots 202 and 203 have been displaced from the slides 29 and 30.

Thus, while the circuit breaker I00 is racked into operative position or at any position between the operative position and the fully racked out or test position, it cannot be released and the racking bar is fully locked in.

Thus, no accidental withdrawal of the circuit breaker I00 from the cubicle I02 can occur while the circuit breaker I00 is in the operative position and the withdrawal of the circuit from the cubicle I02 cannot occur until the fully racked out position or test position of the circuit breaker is reached.

By this means, therefore, a simplified racking bar is provided with simplified sliding bolt means for connecting the racking bar to the cubicle while at the same time an efficient interlock is provided to prevent the insertion of the circuit breaker in the cubicle unless the circuit breaker is fully racked out to the test position; also to prevent the removal of the circuit breaker from the cubicle unless the circuit breaker is first fully racked out to the test position.

In the foregoing I have described my invention solely in connection with specific illustrative embodiments thereof. Since many variations and modifications of my invention will now be obvious to those skilled in the art, I prefer to be bound not by the specific disclosures herein contained but only by the appended claims.

I claim:

1. In a racking mechanism for circuit breakers; a cubicle for housing a circuit breaker; a racking bar having an opening; a racking screw extending through said opening; a circuit breaker mechanism carrying said racking screw and mountable for movement with said racking screw; said racking screw having screw threads engaging with threads in said opening to permit relative movement of said racking screw and the circuit breaker with respect to said racking bar when said racking screw is rotated; a slide member for each end of said racking bar, each slide member having a slotted end; a bolt extending from each end of said racking bar into the slot of the adjacent slide member; a three-way crank mounted adjacent one of said slide members, said crank having a lock and unlock position and a pair of bifurcated crank extensions thereon, a pin connected to said one of said slide members and extending through one of the bifurcated crank extensions, a connecting rod connected at one end of the other of said slide members and having a pin at its other end extending through the other of said pair of bifurcated cranks, said three way crank when rotated causing movement of said slide bars in a direction longitudinally of said racking bars said slide bars moving in opposite directions; a pin extending from each of said slide bars; a bearing mounted on the side walls of said cubicle for receiving said slide member pins when said slide bars have been moved longitudinally away from said racking bar in response to the rotation of said threeway crank to its locked position; said pins when extended into said bearings acting to anchor said racking bar so that when said screw is rotated. said screw and the circuit breaker carrying said screw is moved relative to said racking bar and cubicle; downwardly extending flanges mounted on said circuit breaker, said flanges being in the path of movement of said slide members; said flanges having slots through which slide bars can move to unlocked position when said circuit breaker has been moved to its racked out position, and a flange on said cubicle for preventing entry of said circuit breaker into said cubicle while said slide members are in extended or locked position.

2. In a racking mechanism for circuit breakers; a cubicle for housing a circuit breaker; a racking bar having an opening; a racking screw extending through said opening; a circuit breaker mechanism carrying said racking screw and mountable for movement with said racking screw; said racking screw having screw threads engaging with threads in said opening to permit relative movement of said racking screw and the circuit breaker with respect to said racking bar when said racking screw is rotated; a slide member for each end of said racking bar, each slide member having a slotted end; a bolt extending from each end of said racking barinto the slot of the adjacent slide member; a three-way crank mounted adjacent one of said slide members, said crank having a lock and unlock posi tion and a pair of bifurcated crank extensions thereon, a pin connected to said one of said slide members and extending through one of the bifurcated crank extensions, a connecting rod connected at one end of the other of said slide members and having a pin at its other end extending through the other of said pair of bifurcated cranks, said three way crank when rotated causing movement of said slide bars in a direction longitudinally of said racking bars, said slide bars moving in opposite directions; a pin extending from each of said slide bars; a bearing mounted on the side walls of said cubicle for receiving said slide member pins when said slide bars have been moved longitudinally away from said racking bar in response to the rotation of said three-way crank to its locked position; said pins when extended into said bearings acting to anchor said racking bar so that whensaidscrew is rotated, said screw and the circuit breaker carrying said screw is moved relative to said racking bar and cubicle; downwardly extending flanges mounted on said circuit breaker, said flan es being in the path of movement of said slide members; said flanges having slots through which slide bars can move to unlocked position when said circuit breaker has been moved to its racked out position.

3. In a racking mechanism for circuit breakers; a cubicle for housing a circuit breaker; a racking bar having an opening; a racking screw extending through said opening; a circuit breaker mechanism carrying said racking screw and mountable for movement with said racking screw; said racking screw having screw threads engaging with threads in said opening to permit relative movement of said racking screw and the circuit breaker with respect to said racking bar when said racking screw is rotated; a slide member for each end of said racking bar, each slide member having a slotted end; a bolt extending from each end of said racking bar into the slot of the adjacent slide member; a three-way crank mounted adjacent one of said slide members, said crank having a lock and unlock position and a pair of bifurcated crank extensions thereon, a pin connected to said one of said slide members and extending through one of the bifurcated crank extensions, a connecting rod connected at one end of the other of said slide members and having a pin at its other end extending through the other of said pair of bifurcated cranks, said three-way crank when rotated causing movement of said slide bars in a direction longitudinally of said racking bars, said slide bars moving in opposite directions; a pin extending from each of said slide bars; an anchor formed in said cubicle walls for screwing said slide member pins when they are in extended lock position for anchoring said racking bar; downwardly extending flanges mounted on said circuit breaker, said flanges being in the path of movement of said slide members, said flanges having slots through which slide bars can move to unlocked position when said circuit breaker has been moved to its racked out position, and a flange on said cubicle for preventing entry of said circuit breaker into said cubicle while said slide members are in extended or locked position.

4. In a racking mechanism for circuit breakers; a cubicle for housing a circuit breaker; a racking bar having an opening; a racking screw extending through said opening; a circuit breaker mechanism carrying said racking screw and 9 mountable for movement with said racking screw; said racking screw having screw threads engaging with threads in said opening to permit relative movement of said racking screw and the circuit breaker with respect to said racking bar when said racking screw is rotated; a slide member for each end of said racking bar, each slide member having a slotted end; a, bolt extending from each end of said racking bar into the slot of the adjacent slide member; a three-way crank mounted adjacent one of said slide members, said crank having a lock and unlock position and a pair of bifurcated crank extensions thereon, a pin connected to said one of said slide members and extending through one of the bifurcated crank extensions, a connecting rod connected at one end of the other of said slide members and having a pin at its other end extending through the other of said pair of bifurcated cranks, said three-way crank when rotated causing movement of said slide bars in a direction longitudinally of said racking bars, said slide bars moving in opposite directions; a pin extending from each of said slide bars; an anchor formed in said cubicle walls for screwing said slide member pins when they are in extended lock position for anchoring said racking bar; downwardly extending flanges mounted on said circuit breaker, said flanges being in the path of movement of said slide members, said flanges having slots through which slide bars can move to unlocked position when said circuit breaker has been moved to its racked out position.

5. In a racking mechanism for circuit breakers, a cubicle for housing a circuit breaker; a racking bar having an opening having internal threads, a racking screw extending through said opening, a circuit breaker carrying said racking screw and mounted for movement with said racking screw, said racking screw having threads engaging with threads in said racking bar opening to permit relative movement of racking screw and circuit breaker with respect to said racking bar when said racking screw is rotated; a lock member connected to said racking bar; a handle for moving said lock member to a lock and unlock position, an anchor on said cubicle for receiving said lock member when moved to its lock position for anchoring said racking bar in said cubicle to permit movement of said circuit breaker into and out of said cubicle, a member mounted on said circuit breaker for preventing movement of said lock member while said circuit breaker is in its racked-in position relative to said racking bar and permitting movement of said lock member when said circuit breaker is in its racked-out position relative to said racking bar, and a member on said cubicle for preventing entry of said circuit breaker in said cubicle when said lock member is in its locked position.

6. In a racking mechanism for circuit breakers, a cubicle for housing a circuit breaker; a racking bar having an opening having internal threads, a racking screw extending through said opening, a circuit breaker carrying said racking screw and mounted for movement with said racking screw, said racking screw having threads engaging with threads in said racking bar opening to permit relative movement of racking screw and circuit breaker with respect to said racking bar when said racking screw is rotated; a lock member connected to said racking bar; a handle for moving said lock member to a lock and unlock position, an anchor on said cubicle for receiving said lock member when moved to its lock position for anchoring said racking bar in said cubicle to permit movement of said circuit breaker into and out of said cubicle, a member mounted on said circuit breaker for preventing movement While said circuit breaker in its relative position with respect to said racking bar corresponds to its racked-in position in said cubicle and for permitting movement of said lock member when said circuit breaker position with respect to said racking bar corresponds to its racked-out position.

7. In a racking mechanism for circuit breakers, a cubicle for housing a circuit breaker, a racking bar, a racking member movable with respect to said racking bar, a circuit breaker carrying said rackin member and movable therewith relative to said racking bar, a slide member for each end of said racking bar, each slide member having a slotted end, a bolt extending from each end of said racking bar into the slot of the adjacent slide member; a three way crank mounted adjacent one of said slide members, said crank having a lock and unlock position and a pair of bifurcated crank extensions thereon, a pin connected to said one of said slide members and extending through one of the bifurcated crank extensions, a connecting rod connected at one end of the other of said slide members and having a pin at its other end extending through the other of said pair of bifurcated cranks, said three way crank when rotated causing movement or said slide bars in a direction longitudinally of said racking bar, said slide bars moving in opposite directions, a pin extending from each of said slide bars; a bearing mounted on the side Walls of said cubicle for receiving said slide member pins when said slide bars have been moved longitudinally away from said racking bar in response to the rotation of said three-way crank to its locked position; said pins when extended into said bearings acting to anchor said racking bar so that when said screw is rotated, said screw and the circuit breaker carrying said screw is moved relative to said racking bar and cubicle; downwardly extending flanges mounted on said circuit breaker, said flanges being in the path of movement of said slide members; said flanges having slots through which slide bars can move to unlocked position when said circuit breaker has been moved to its racked out position, and a flange on said cubicle for preventing entry of said circuit breaker into said cubicle while said slide members are in extended or locked position.

8. In a racking mechanism for circuit breakers, a cubicle for housing a circuit breaker; a racking bar having an opening; a racking screw extending through said opening; a circuit breaker mechanism carrying said racking screw and mountable for movement with said racking screw; said racking screw having screw threads engaging with threads in said opening to permit relative movement of said racking screw and the circuit breaker with respect to said racking bar when said racking screw is rotated; a slide member for each end of said racking bar, each slide member having a slotted end; a bolt extending from each end of said racking bar into the slot of the adjacent slide member; a three-way crank mounted adjacent one of said slide members, said crank having a lock and unlock position and a pair of bifurcated crank extensions thereon, a pin connected to said one of said slide members and extending through one of the bifurcated crank extensions, a connecting rod connected at one end of the other of said slide members and having a pin at its other end extending through the other of said pair of bifurcated cranks, said three way crank when rotated causing movement of said slide bars in a direction longitudinally of said racking bars said slide bars moving in opposite directions; a pin extending from each of said slide bars; a bearing mounted on the side walls of said cubicle for receiving said slide member pins when said slide bars have been moved longitudinally away from said racking bar in response to the rotation of said three-way crank to its locked position; said pins when extended into said bearings acting to anchor said racking bar so that when said screw is rotated, said screw and the circuit breaker carrying said screw is moved relative to said racking bar and cubicle; a member mounted on said circuit breaker for preventing movement of slide members to its unlock position while said circuit breaker in its relative position with respect to said racking bar corresponds to its racked-in position in said cubicle and for permitting movement of said slide members when said circuit breaker position with respect to said racking bar corresponds to its racked-out position, and a member on said cubicle for preventing entry of said circuit breaker in said cubicle when said slide member is in its locked position.

9. In a racking mechanism for circuit breakers, a cubicle for housing a circuit breaker; a racking bar having an opening having internal threads, a racking screw extending through said opening, a circuit breaker carrying said racking screw and mounted for movement with said racking screw, said racking screw having threads en- 12 gaging with threads in said racking bar opening to permit relative movement of racking screw and circuit breaker with respect to said racking bar when said racking bar is rotated; a lock member connected to said racking bar; a handle for moving said lock member to a lock and unlock position, an anchor on said cubicle for receiving said lock member when moved to its lock position for anchoring said racking bar in said cubicle to permit movement of said circuit breaker into and out of said cubicle, a movable member, means including said movable member for preventing movement of said lock member while said circuit breaker is in its racked-in position relative to said racking bar and permitting movement of said lock member when said circuit breaker is in its racked-out position relative to said racking bar, and a member on said cubicle for preventing entry of said circuit breaker in said cubicle when said lock member is in its locked position.

ARTHUR S. CASWELL.

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

UNITED sTATEs PATENTS Number Name Date 1,706,114 Gordon Mar. 19, 1929 1,729,864 Brown Oct. 1, 1929 2,273,002 Mahoney Feb. 10, 1942 2,544,314 Hebbel Mar. 6, 1951 2,554,510 Spicer May 29, 1951

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