US3851772A

US3851772A - Device for transferring objects

Info

Publication number: US3851772A
Application number: US00367077A
Authority: US
Inventors: R Williamson; S Porter; K Shotting
Original assignee: Combustion Engineering Inc
Current assignee: Premier Refractories and Chemicals Inc
Priority date: 1972-05-15
Filing date: 1973-06-04
Publication date: 1974-12-03
Anticipated expiration: 1991-12-03

Abstract

A transfer device for transferring an object at a first location in a first position to a second location in a second position. The device comprises two spaced arms, arm rotating means for rotating the two spaced arms, gripping means for each of the arms for picking up the object, and an object rotating means for controllably rotating the object relative to the arms as the arms are rotated from a first location to a second location. At least one of the gripping means is a rotating gripper rotatably mounted on one of the arms, and the object rotating means includes a sprocket mounted on the rotating gripper; a spring means on the one arm having the rotating gripper, and a chain adapted to engage the sprocket and having one end fixed to the spring and the other end fixed to a mounting point separate from the arms. The position of the mounting point is such that, upon rotation of the arms, the distance along the chain between the sprocket and the mounting point changes and thereby causes the sprocket to rotate the rotating gripper. This in turn causes the object to be rotated from a first position to a second position.

Description

United States Patent 1 [111 3,851,772

Williamson et al. I Dec. 3, 1974 DEVICE FOR TRANSFERRING OBJECTS [57] ABSTRACT [75] Inventors: Ronald Eugene Williamson, A transfer device for transferring an object at a first Hammonsville; Sidney Clark Porter, location in a first position to a second location ina Jr., East Liverpool, both of Ohio; second position. The device comprises two spaced Kenneth Frederic Shotting, arms, arm rotating means for rotating the two spaced Coraopolis, Pa. arms, gripping means for each of the arms for picking up the object, and an object rotating means for controllably rotating the object relative to the arms as the arms are rotated from a first location to a second loca- [22] Filedz June 4, 1973 tion. At least one of the gripping means is a rotating gripper rotatably mounted on one of the arms, and the [211 Appl' 367077 object rotating means includes a sprocket mounted on [73] Assignee: Combustion Engineering,lnc.,

Windsor, Conn.

Related U.S. Application Data the rotating gripper; a spring means on the one arm [62] Division of Set. No. 253,546, May 15, 1972, Pat. No. having the rotating pp and a Chain adapted t0 3,757,484. gage the sprocket and having one end fixed to the 7 spring and the other end fixed to a mounting point [52] U.S. Cl. 214/1 Q separate from the rms. The position of the mounting [51] Int. Cl. 865g 7/08 point is such that, upon rotation of the arms, the dis- [58] Field of Search 214/1" BV, 1 BD, 1 Q, 1 H, tance along the chain between the sprocket and the 214/13() R, 147 R, 147 G, 147 T, 1 QA, 653 mounting point changes and thereby causes the sprocket to rotate the rotating gripper. This in turn [56] R f ences Cit d causes the object to be rotated from a first position to UNITED STATES PATENTS a second posmom 2,697,529 12/1954 Hubbell et al 214/147 T 3,758,365 9/1973 Schilling 2:4 1 o x 6 Clams, 16 Drawing Figures Primary ExaminerFrank E. Werner Attorney, Agent, or Firm-John R. Nelson PATENTELBEB sum i on or 11 vow 9N wt oh wow m2 92 v9 NON mom OON MIN 2N PATENmm- 31974 I 3,851,772

sum #05 any PATENTLLUEC 3mm 3.851.772

sum '88 0F 11 FIG. 9

PATENTLU 313 31974 SHEET (09 0F 11 DEVICE FOR TRANSFERRING OBJECTS This is a division of application Ser. No. 253,546 filed May 15, 1972, now US. Pat. No. 3,757,484 and entitled Automated Bricklaying Device.

BACKGROUND OF THE INVENTION The above-identified parent application relates to an automated bricklaying device for laying of refractory bricks within a metal pouring ladle to serve as the working lining thereof. In the preferred form of that invention, the refractory bricks are first delivered on a conveyor to a location adjacent the circumference of the ladle, the bricks being oriented in an upright position. It is then necessary to provide a means for transferring the bricks from this location and in this position (upright) to a second location (circumference of ladle) and in a second position (horizontal). That is, the bricks have to be transferred to the ladle circumference and oriented in a horizontal position. It is to an apparatus for accomplishing this transfer that the present invention is directed.

SUMMARY OF THE INVENTION The transfer device of the present invention is operable to transfer an object at a first location in a first position to a second location in a second position. Although the invention is disclosed and described as being usable in a bricklaying machine, this is not meant to be limiting of the scope of the invention. The transfer device comprises two spaced arms, means for rotating the two spaced arms, gripping means for each of the arms for picking up the object, and an object rotating means for controllably rotating the object relative to the arms. At least one of the gripping means is a rotating gripper rotatably mounted on one of the arms. The object rotating means includes a sprocket mounted on the rotating gripper, a spring means mounted on the arm having the rotating gripper. and a chain adapted to engage the sprocket and having one end fixed to the spring and the other fixed to a mounting point which is separate from the'arms. The mounting point is positioned separate from the arms such that, upon rotation of the arms by the arm rotating means, the distance along the chain between the sprockets and the mounting point changes, this in turn causing the sprocket to rotate the rotating gripper. This rotation causes the object to be rotated .from its first position to its second position.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation view of the automated bricklaying device according to the present invention positioned within a ladle shell;

FIG. 2 is a front elevation view, partly in section, 7

taken along line 2-2 of FIG. I with a portion thereof removed;

FIG. 3 is a top view of the automated bricklaying device taken along line 33 of FIG. 1;

FIG. 4 is an elevation view, partly in section, taken along line 4-4 of FIG. 3;

FIG. 5 is a detailed section view of the conveyor indexirig mechanism according to the present invention taken along line 55 of FIG. 3;

FIG. 6 is a perspective view of the brick gripper according to the present invention;

FIG. 7 is an elevation view of a portion of the conveyor assembly taken along line 7-7 of FIG. 11;

FIGS. 8A and 8B are diagrammatic representations showing the operation of the brick gripper according to the present invention;

FIG. 9 is a front elevation view of the conveyor assembly taken along line 9-9 of FIG. 10;

FIGS. 10, 11 and 12 are detailed plan views of a portion of the conveyor assembly showing the sequential operations according to the present invention in laying a brick in the lining of the ladle;

FIG. 13 is a detailed view showing the actuation of a limit switch utilized in the control of the present invention;

FIGS. 14A and 14B are diagrammatic representations of the control system according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, FIGS. 1 and 2 show an automated bricklaying device positioned within a metal pouring ladle 22. The ladle 22 is comprised of a steel shell 24 with a safety lining 26 forming the interior thereof. Within the safety lining 26 is a working lining 28 which is periodically damaged and eroded during the steel-making process and needs to be replaced. It is the replacement of this working lining 28 to which the particular bricklaying device 20 of this invention is concerned.

The automated bricklaying machine is comprised of three separate assemblies such that it may be installed and removed from the ladle in three pieces or sections, or alternatively it may be installed or removed as a unit.

'These three assemblies are the support assembly 30,

the elevator frame assembly 64, and the carriage assembly 90. The support assembly 30, as depicted in FIGS. 1 and 2, is a turntable mechanism comprised of a lower platen 32 supported on the floor of the ladle 22 by means of leveling screws 40 mounted in flanges 38 spaced about the periphery of the platen 32 and an upper platen 34 having a central downwardly extending shaft 36 journaled in bearing 35 on the lower platen 32. The upper platen 34 is supported from the lower platen 32 for rotation relative thereto about the shaft 36 by a plurality of rollers 44 intermittently spaced about and journaled in an upright ring 42 positioned at the periphery of the lower platen 32. An annular gear ring 46 having outwardly extending gear teeth is centrally located on the lower platen by an inner locating ring 48 for engaging a pinion gear 50 having a shaft 52 journaled in a bearing 54 of the upper plate 34. A sprocket 56 is rigidly fixed to the shaft 52 above the platen 34 and is connected to a rotary air motor 60 by a chain 58 for rotating the pinion gear 50 which in turn will rotate the upper platen 34 relative to the lower platen 32.

The elevator frame assembly 64 is comprised of two spaced T-shaped standards 65 formed by joining together a rectangular beam 66 and a flat plate 67 as shown in FIGS. 1, 2 and 3. Each of the standards 65 has integrally attached thereto at its lower end a connecting couple 68 whose inner surface conforms identically to the outer surface of lugs 62 provided on the platen 34, the lugs 62 serving to support the elevator frame assembly at an angle conforming to the slope of the ladle wall 24. A pin 69 passes through the lugs 62 and the connecting bases 68 to hold the standards in place. Standards are interconnected and held in spaced relation by a tie bar 70 at the bottom, an X-brace 72 near the top and a tie bar support at the top, the support 80 having lifting holes 88 for introducing into or removing from the ladle 22, either the elevator frame assembly 64 or the entire bricklaying device 20. A hoist motor support 76 integrally attached to the standards 65 extends laterally outward from the elevator frame assembly and supports a rotary air actuated hoist motor 78 thereon. A cable 86 extending from the hoist motor 78 passes over sheaves 81 separated by sheave spacers 83 of the upper and

lower hoist blocks

82 and 84, the upper hoist block 82 being supported from the tie bar support 80 and the lower hoist block 84 being supported by the cable 86. Actuation of the hoist air motor 78 will effectuate either a lowering or raising of the lower hoist block 84.

The carriage platform assembly is carried by the elevator frame assembly 64 in such a manner so as to be vertically movable within the ladle 22. The carriage assembly 90 has horizontal base members 94 supporting a platform 92-. Two carriage upright supports 96 extend upward from the base members 94 inclined relative to the plate at an angle substantially equal to the incline angle of the ladle and elevator frame assembly 64. The upper portion of the uprights 96 are interconnected by cross support 98 having integrally attached thereto a downwardly extending pin 108. As best seen in FIG. 4, the cross support 98 and thus the carriage assembly 90, is supported from the elevator frame assembly 64 by the lower hoist block extension 84, the pin 108 passing through a hole in the extension 84 and being retained in place by a cotter pin extending through a transverse hole in the pin 108. This manner of supporting the carriage assembly is advantageous in that the lower hoist block 84 remains coupled to the elevator frame assembly 64 upon removal of the carriage assembly 90 therefrom.

A plurality of

rollers

100, 104 and 106 are rotatably mounted from the upright supports 96 so that the carriage platform assembly 90 will be guided in its vertical movement within the ladle 22 by the elevator frame assembly 64. The upper set of rollers 100 ride on the rear surface of the plate 67 of the elevator standard 65 and are journaled in plates 102 extending outward from the uprights 96 on either side of the standards 65 while the lower rollers 106 are journaled in the uprights 96 to ride along the front surface of the plate 67. The combination of these two sets of

rollers

100, 106 provides the necessary stability to insure that the carriage assembly 90 remains in position as it is moved up and down the standards 65. Lateral stability is provided for the carriage assembly 90 by the rollers 104 which pass along the outside edges of the flat plate 67. There are two rollers 104 positioned at the upper portion of the uprights 96 and two positioned at the lower portion.

A boom mechanism 118 is supported from the cross support 98 for lifting bricks 144 from the pallets of bricks on the platform 92 and placing them on a delivery means or conveyor assembly 146 to be described hereinbelow. A support member 120 attached to the cross support member 98 carries pivot pin 126 to which is mounted for pivotal movement in a horizontal plane a first beam 122. A second beam 124 is pivotally connected by pin 128 to the first beam 122. A hoist motor 130 is attached to the distal end of the second beam 124 and a cable 131 extends downward therefrom to carry ice tong grippers 132. The ice tong grippers are comprised of two hollow tubes 134 into which extend bars 136 having gripping surfaces 138 at the distal ends, the tubes 134 being pivotally connected by pin 140. Screws 137 tightly hold the bars 136 in place within the tubes 134. The cable 131 is attached to lugs 142 of the tubes 134 such that upon actuation of the air hoist 130 to retract the cable 131, the hollow tubes 134 pivot about pin to grip a series of bricks 144, the bricks then being lifted from the pallet and placed on the conveyor assembly 146.

As best seen in FIGS. 2, 3, 4 and 9, the platform 92 has been cut away between the horizontal support braces 94 so as to provide a channel opening 112 into which extends the conveyor assembly 146. Upper and lower flange means 114 and 116 provided on the horizontal support braces serve to support the conveyor assembly 146.

The conveyor assembly 146 is comprised of two spaced

frame members

148 and 150, interconnected by cross support 152, end plate 154 and back and

front plates

156 and 158. Support rollers 160 are journaled in the sides of the

frame members

148 and 150 and engage the upper and lower flange means 114, 116 to support and allow free lateral movement of the conveyor assembly 146 within the channel opening 112. The frame member 150 has four rollers journaled therein while the frame member 148 has only two since frame member 150 will necessarily have to support a greater weight than member 148, as described hereinbelow. An axial air motor 162 is attached to the inner surface of the frame member 150 with one end connected to a push plate 164 and the other end connected to the end plate 95 of the carriage assembly 90. The air motor 162 serves the purpose of extending the conveyor assembly 146 outward toward the lining of the ladle or retracting it inward into the carriage assembly 90.

Two chains 166, provided between the

frame members

148 and 150, serve as a conveyor to deliver bricks to the front end of the conveyor assembly 146. The chains 166 are mounted on two sets of sprockets 168, 174, the rear sprockets 168 being interconnected by a common shaft 172 journaled in support on the rear plate 156 and the front sprockets 174 being interconnected by common shaft 175 journaled in support 176 attached to the cross support 152. The chains 166 are driven, in one direction only, by a conveyor indexing means 178 which is best seen in FIG. 5. The indexing means 178 comprises a one-way friction clutch sprocket 182 having an outer sprocket 184 with inner cam surfaces 190, an inner cylinder 186 mounted on the common shaft 172 of the rear sprockets 168 and a plurality of balls 188 located therebetween. A forward indexing sprocket 181 and an axial air motor 192 with piston rod 194 are mounted to a forward sprocket mount attached to frame member 148. The piston rod 194 has attached thereto a chain connector 198 which in turn is connected to the ends of a chain 196 passing over the forward indexing sprocket 181 and the one-way friction clutch sprocket 182. Extension of the piston rod 194 will effect a clockwise rotation of the outer sprocket 184 which will cause the balls 188 to become tightly engaged between the cam surfaces 190 and the inner cylinder 186 so that the inner cylinder 186, and in turn the shaft 172, will rotate clockwise. This action causes the chains 166 to move bricks forward toward the front of the conveyor assembly 146. Upon retraction of the piston rod 194, however, the outer sprocket 184 rotates counterclockwise and the balls 188 disengage the inner cylinder 186, thereby imparting no counterclockwise rotation to the common shaft 172. Instead, the chains 166 remain stationary.

Located in the forward portion of the conveyor assembly 146 are three devices for placing and properly positioning the bricks in the wall of the lining 28 as they are delivered along the chains 166: a conveyor positioning mechanism 200, a brick pusher 236 and a brick gripper 264. The conveyor positioning mechanism 200, as best shown in FIGS. 4, 10, 11 and 12, serves a dual function of orienting the extension of the conveyor assembly 146 and also the height of the system relative to the lining of the ladle. A wheel holder 202 is attached to the conveyor assembly 146 in a dog leg connection by a pin 204 so as to allow pivotal movement of the wheel holder 202 thereabout. A support arm 210, pin connected to the wheel holder 202 by pivot pin 212, has journaled inits distal end a conveyor extension wheel 208 for riding along the interior surface of the lining 28. The conveyor extension wheel 208 controls actuation of the conveyor extending motor 162 so as to maintain a constant outward force against the interior of the ladle as bricks are being laid in place. Adjustment of the orientation of the conveyor extension wheel 208 is controlled by a pin 215 on support arm 210 passing through an adjusting slot 214 in the wheel holder 202 and held in place by a nut 216. A support cam follower wheel 206 is journaled in the front face of the wheel holder 202 for riding along the top row of bricks 144 in the lining 28 to control adjustment of the height of the carriage assembly 96. This is accomplished by means of a pressure regulator mounted in housing 220 on frame member 150. A pusher block 230 having a regulator plunger 232 adapted to enter the regulator is threaded on a screw 228 attached to the rear support plate 218 of the wheel holder 202. As the cam follower wheel 206 rides on the lining 28, the wheel holder will pivot about pin 204 to force the plunger 236 into the regulator causing the air hoist 78 to actuate and raise the carriage assembly 90. A spring 222 shown in FIG. 4 is attached between a stop 226 and the support plate 218 to bias the wheel holder outward to force the plunger 236 out of the regulator, thereby causing the air hoist to stop. Generally the spring force is sufficient to allow the cam follower wheel 206 to support about 5 percent of the weight of the carriage assembly 90. Thus it is apparent that an extra set of rollers 160 are necessary for supporting frame member 150 in the carriage assembly 90.

The brick pusher 236 as best shown in FlGS. 7 and 10-12 is attached to the other frame member 148 by means of an upright mounting plate 239 which supports a rotary air actuator 238 with a substantially vertically extending shaft 240. The shaft 240 has attached thereto at its lower end a linkage system comprised of a drive arm 242 having a drive arm extension 244 pinned at its distal end by pin 243. A drive arm wheel holder'246 having a drive wheel 250 pinned thereto by pin 252 is integrally attached at an angle to the drive arm extension 244 such that the wheel 250 will rotate in a plane parallel to the upper surface of the lining 28. A linkage arm 248 pinned to the air motor 238 by pivot pin 247 and pinned to the drive arm extension 244 by pivot pin 249 controls the relative motion of the arm 244. As can be seen in the sequential views of FIGS. 10-12 as the shaft 240 is rotated in a counterclockwise rotation the drive wheel 250 travels along a fixed path to engage the lastly laid brick and push it into place in the lining 28.

Operation of the brick pusher 236 is controlled by two

limit switches

257 and 261 positioned on a mounting plate 256 and the top surface of the air motor 238 respectively. A shaft block 254 attached to shaft 240 has adjustably positioned thereon two actuating

members

258 and 262. Upon actuation of the air motor 238, the shaft 240 will rotate in a counterclockwise motion, forcing the lastly laid brick 144 against the next to lastly laid brick in the lining 28 until the forward limit switch 261 is actuated by the plate 262. A signal will then be sent to reverse the motion of the shaft 240 to return the brick pusher to its retracted position, the operation of the air motor 238 ceasing when the block 258 actuates the return limit switch 257.

The brick gripper 264 for placing a brick 144 in the lining 28 is positioned on two base pads 270 on the front of the front plate 158, and comprises an air motor 266 which rotates a shaft 268 extending outward from both sides thereof as best seen in FIGS. 6 and 10-12. Two spaced

arms

272 and 282 are attached to the protruding ends of the shaft 268. Swing arm 272 is attached to the shaft 268 by means of two spaced flanges 274 engaging a block 276 rigidly fixed to the shaft 268 and a pivot pin 278 passing therethrough. The distal end of the swing arm 272 is provided with a gripping pivot point 280 for gripping one end of the brick 144 and allowing the brick to rotate thereabout. The positioning arm 282 is rigidly fixed to the shaft 266 so as to only rotate therewith. The distal end of the positioning arm 282 is provided with a rotating gripper 284 and a sprocket 288 interconnected by a shaft 286 journaled in the arm 282. A clamping axial air motor 308 is pin connected to the positioning arm 282 by pin 3.12, and has a piston rod 310 connected to the swing arm 272 by pivot pin 314. Retraction and extension of the piston rod within air motor 308 will cause the swing arm 272 to pivot about the pin 278 to grip r0 release, respectively, a brick 144 between the gripping point 280 and the rotating gripper 284.

As best shown in FIGS. 6, 7 and 10, a fixed sprocket 290 is rotatably mounted on a shaft 291 which is adjustably fixed within a slot 293 in a mounting bracket 292 affixed to the front plate 158 in spaced relation from the air motor 266. The vertical elevation of the shaft 291 is substantially the same as that of the shaft 268 of the air motor 266. Positioned on the rear of the mounting bracket 292 is an axial air motor 294 with a piston rod 296 extending outward therefrom toward the fixed sprocket 290. A chain 298 is mounted around a roller 302 journaled in the side of the positioning arm 282, and the two

sprockets

288 and 290, one end of the chain being mounted to the piston rod 29.6 and the other end being fixed to a spring 300 attached to the side of the positioning arm 282 by pin 304.

The bricks 144 are delivered in what is termed an upright position lying on a longitudinal edge to the front of the conveyor assembly 146 where the brick gripper 264 grasps the bricks and translates them to the wall of the ladle 22 to form the lining 28 thereof. The bricks must be reoriented from the upright position to a horizontal position since the bricks of the lining 28 lie on one side wall surface with one of the longitudinal edges abutting the safety lining 26 and the other longitudinal edge facing inward toward the center of the ladle, As previously noted, the bricks are standard refractory bricks generally described in Us. Pat. No. 3,140,333 with one of the longitudinal edges being longer than the other. Normally, in a circular ladle, the longer of the two longitudinal edges is placed against the safety lining 26 so that successive bricks in the lining naturally are or bend to conform to the circular surface of the ladle. Often, however, the size of the ladles used in steel shops is increased by making the ladles elliptical in fashion with flat spots or regions on the circumference of the ladle. In this situation, it is necessary along the flat region to alternately reverse the orientation of the bricks so that the short longitudinal edge is alternately placed against the ladle safety lining 26 to form a straight region of lining. This is shown at flat region 29 on FIG. 3, the S denoting a short longitudinal edge and L denoting a long longitudinal edge. It is this dual reorientation of the bricks with which the chain 298 and

sprockets

288, 290 are concerned, the operation of which is best seen in FIG. 8A and 8B.

The center of the fixed sprocket 290 is positioned behind the pivot point of the gripper arm 282 so that rotation of the arm 282 will cause a change in the distance along the path of the chain 298 between the end of the piston rod 296 and the sprocket 288 on the arm 282. The spring 300 connected to the end of the chain 298 either extends or compresses to accommodate this change in distance and in turn causes the sprocket 288 to rotate relative to the arm 282. For rotation of the arm 282 from position A to position C in FIG. 8A, the distance becomes less and the spring 300 compresses to pull the chain 298 around the sprocket 288 thereby causing a clockwise rotation of the sprocket and brick relative to the arm 282. For example, in position A, the arm 282 is oriented at an angle of 26- /2" and picks up a brick 144 lying on its short longitudinal edge (denoted by S). The initial length of spring 300 is d, and the center of the fixed sprocket is spaced a distance p behind the pivot point of the arm 282. When the rotary air motor 266 is actuated, the arm 282 rotates counterclockwise 159 through position B to position C where the bricks 144 are released, the arm 282 being 5- /2 below the horizontal, and the brick 144 having rotated clockwise 63-" so that it is roughly parallel to the top surface of the lining 28. The spring 300 has compressed to a length d The distance p between the center of the sprocket290 and the pivot axis of the arm 282 depends on the size of the

sprockets

288 and 290 and the amount of rotation of the arm 282 and may be determined empirically in order to effectuate the desired rotation of the brick 144.

For the situation where the brick 144 is to be laid in the lining 28 in a reverse orientation, (i.e., the short longitudinal edge abutting the safety lining 26) the piston rod 296 of the air cylinder 294 is retracted to rotate the brick 144 counterclockwise during rotation of the arm 282 by the air motor 266. Using the same example as above for FIG. 8A, the brick 144 is initially grasped when the arm 282 is in position A with the spring 300 having a length d,, and the piston rod 296 extended fully. However, as the arm 282 is rotated from position A through B to C, the piston rod 296 is retracted a distance r, causing the brick 144 to rotate counterclockwise I l6- /2 relative to the arm 282 such that the short longitudinal edge is adjacent the lining 26. In this situation, the spring 300 stretches from d, in position A to d in position C. Again the distances p and r are dependent on the size of the

sprockets

288, 290 and the amount of rotation of the arm 282 and may be determined empirically.

Of course it should be understood that there are other ways of combining the spring 300, the chain 298, and the two

sprockets

288, 290 to properly reorient the brick 144 before it is placed in the lining 28 of the ladle 22. This may be accomplished simply by wrapping the chain 298 in the opposite direction around the sprocket 288, that is, first passing the chain 298 underneath and then around the top of the sprocket 288 to the spring 300. In this situation the spring 300 would stretch and the sprocket 288 would rotate clockwise during the rotation of the arm 282 for laying both a normal oriented and a reverse oriented brick 144. Or the size of the

sprockets

288, 290 could be varied and the separation between the center of the fixed sprocket 290 and the center of rotation of the arm varied, or even the position of the fixed sprocket 290 could be changed. The only thing necessary in making these changes is to ensure that it is possible to effectuate two different amounts of angular rotation of brick 144 as the arm 282 is rotated from position A (picking brick up) to position C (releasing brick).

Also provided on the front plate 158 of the conveyor assembly are several mechanisms for controlling the operation of the brick laying machine 20. As shown in FIGS. 6 and 7, an arm stop slide 340 is adjustably positioned along a bracket 342 by means of a screw 344. An upward protruding member 341 is provided on the arm stop slide 340 for controlling the height ofthe

gripper arms

272, 282 when picking up a brick 144. Forward motion of the

arms

272, 282 is controlled by a limit switch 306 which in the preferred embodiment in FIG. 6 is shown to be attached to the front of the air motor 266. Upon actuation of limit switch 306, the

arms

272, 282 stop rotating and the brick 144 held therebetween is released with the arms then returning to pick up another brick. The advancement of the bricks 144 along the chains 166 is controlled by a brick limit switch 346 attached to a bracket 348 adjustably locatable on the front sprocket support 176 by means ofa screw 350 as shown in FIGS. 7 and 10. Upon actuation of the limit switch 348, the bricks are stopped and remain stationary until the forwardmost brick is picked up by the gripper 264.

A brick aligner mechanism 316 for ensuring alignment of the bricks 144 on the conveyor chains 166 comprises an axial air motor 318 adjustably mounted on a bracket 320, positioned on the frame member as shown in FIGS. 6, 7, 9 and 10. The axial air motor 318 has a piston rod 322 to the end of which is attached a disc 324. As the bricks 144 are advanced along the chain 166, the air cylinder 318 is periodically actuated to extend the disc 324 to push the bricks transversely on the chain 166 thereby aligning them for pickup by the gripper mechanism 264.

Also positioned on the conveyor assembly 146 is a mortar bucket 326 supported by a cross support 330 connected to two uprights 328 mounted on

frame members

148 and 150 as shown in FIGS. 1, 2 and 7.

The mortar bucket 326 contains a slurry type mortar delivered to the lining 28 by gravity in a flexible hose 334, one end of which is connected to the lower nozzle 332 of the mortar bucket 326 and the other end of which is positioned in a nose support 338 extending outward from the air motor 238. A control valve or clamp means 336 having an actuator 337 is provided for controlling the flow of mortar to the lining. It should be noted that the use of mortar is not necessary due to the interlocking action of the bricks 144, but is merely shown for the situation where it is desired to supplement the holding of the bricks in place in the lining.

The operation of the automated bricklaying device is as follows. The ladle 22 is cleaned of excessive slag and dirt accumulation and inspection and repair of the bottom and the safety lining 26 is undertaken in the conventional manner. The bottom brick lining and well block are laid up as is the skew brick ring which is comprised of one tapered starter set 27 and several spiraling courses of semi-universal refractory brick 144, also in the conventional manner. The tapered starter set is necessary to provide that the working lining 28 is built up by spiraling courses.

The automated bricklaying device 20 is then lowered into the ladle, either as a whole unit or in components as previously noted and leveled by screw jacks 40 on turntable 30 to rest on the bottom brick lining. The bricklaying machine may then be connected to a power source and operated in a manner to be described hereinbelow.

As previously noted, the bricklaying device 20 in the preferred embodiment is a totally air operated device as opposed to, for example, an electrically operated device. This is merely a matter of preference, depending on the type of shop in which the bricklaying machine will be used and the capabilities thereof, and it makes no major difference what type of power source is employed. It is conventional in most steel shops to use air as a source of power to operate various devices for operation therein and, as such, air was initially chosen to supply the power for operation.

The particular control diagram 400 for the preferred embodiment is depicted diagrammatically in FIGS. 14A and 148. As a key to aid in understanding the diagrammatic representation, the following should be noted. The

numbers

412 and 414 on FIG. 14A represent typical main air supply lines for operating the various air motors and air cylinders of the bricklaying machine 20; the

numbers

428 and 442 on FIG. 14A represent typical pilot lines for switching control valves from one position to another; the number 476 on FIG. 14A represents a typical check valve which permits air to flow in the line 478 in one direction (to the right) and prohibits air flow in the other direction (to the left); the number 594 of 148 represents a typical adjustable flow control valve to control the flow of air therethrough; the number 474 on FIG. 14A represents a typical pressure regulator which controls the amount of air pressure delivered to the left-hand portion of the line 414; the number 424 on FIG. 14A represents a typical mechanically actuated control valve with a spring return which will return to its normal position upon release of the operator; the number 518 on FIG. 14B represents a typical air actuated control valve whose position is changed by providing air to one of the chambers A or B, the valve remaining in that position until air is pro vided to the other of the chambers; and the numbers 408 on FIG. 14A and 538 on FIG. 14B represent typical manually actuated control valves whose position is changed manually and maintained thereat by detents.

With the above brief description of the diagrammatic representation in FIGS. 14A and 14B, the operation of the bricklaying machine 20 is as follows. The main supply of air to the machine is provided from a compressor (not shown) by the supply line 402, a filter 404 and lubricator 406 being provided in the line 402 so that the air to the system is clean and lubricated. Air is supplied by branch line 416 to the control valve 418 to operate the air hoist 130 of the boom mechanism 118 independent of the rest of the system. The control valve 418 is a three-position valve for controlling the air motor 130 to raise, to lower, or to stop the cable 131. Actuator 419U shifts the valve 418 to supply air from line 416 to line 420 to raise the cable 131, with air in down line 422 exhausting through vent line 421 while the actuator 419D shifts the valve 418 to the other side so that air is delivered to the down side of the air motor 130 to lower the cable 131.

The remainder of the operation of the bricklaying machine is controlled by the three-position manuallyactuated valve 408 which, in FIG. 14A, is shown in a neutral position sending no air to the system. Initially the valve 408 is placed in the manual" position so that air will be provided from the branch line 410 to the main manual control line 412, and the air in the automatic line 414 will exhaust to the atmosphere through vent line 413. The main hoist valve 434, as with the valve 408, is a three-position valve to which air is delivered via

lines

412, 415, 430 and 436 to control the air hoist 78 for raising and lowering the carriage platform assembly 90 on the elevator frame assembly 64. The control system is also provided with a conventional spring biased brake 450 and a slack cable limit switch 426 for restricting operation of the air hoist 78. The

brake 450 automatically locks the air hoist 78 in place if no air is sent to it along pilot line 452 and the slack cable limit switch releases the air in

line

429, 452 if the cable 81 of the hoist 78 is slack, the slack position being shown in FIG. 14A. If the cable 81 is'not slack, the valve 426 is depressed so that no air will be released from line 429 as described hereinafter. Pilot air is delivered for manual operation by

pilot lines

442 and 446 joined to the air hoist up and down

lines

438 and 440 respectively. Check valves 444 and 448 are positioned in

pilot lines

442, 446 to prevent a reverse flow from one pilot line to the other, which would prevent release of the brake 450.

Lowering of the cable 86 of the hoist 78 and thus the carriage assembly 90, is accomplished by placing valve 434 in the down" position so that air will be provided from line 436 through line 440 to both the brake 450 and the down side of the air hoist 78. Air is released from the up" side of the motor 78 through the up" line 438 to vent line 439. The carriage assembly 90 is lowered until it is at the approximate height necessary to start laying bricks in the lining, in which case the valve 434 is placed back in its neutral position (see FIG. 4). Next, the conveyor assembly 146 is extended from beneath the carriage assembly 90 so that the conveyor extension wheel 208 rides against the inner surface of the lastly laid bricks in the lining 28. The conveyor extension valve 464 is placed in the out position and air is delivered to the extension air motor 162 i by

lines

412, 415, 458 and 466. A pressure regulator 460 in the line 458 controls the amount of air pressure in line 458 to the right of the regulator 460 and as such the amount of pressure delivered to the extension motor 162. Normally the regulator 460 is set so as to provide a sufficient force on the conveyor extension wheel 208 to properly set the bricks 144 in the lining 28 against the safety lining 26, this occurring as the conveyor assembly 90 revolves around the circumference of the ladle, notwithstanding the fact that the turntable assembly is not positioned in the center of the ladle and notwithstanding the fact that the ladle may be elliptical. As air is delivered to the extension motor 162 by line 466, air in the in line 468 is controllably released to the atmosphere through the vent line 470 and flow control valve 472 situated therein.

After the conveyor assembly 146 has been properly positioned against the lining 28, the carriage assembly is again lowered until the cam follower wheel 206 rests on the top surface of the lining 28. A manual override valve 424 has been provided where it is desired to release the brake 450 when the cable 86 on the air hoist 78 is slack, such as might occur if the hoist 78 were lowered too far when the cam follower wheel 206 rested on the lining 28. When the valve 424 is actuated, air passes from branch line 423 to pilot line 428 to actuate the slack cable limit switch 426 so that air in line 429 is not released to the atmosphere through vent line 427, but instead passes to release the brake 450. Although the valve 426 is positioned to pass air from line 429 through line 484 to line 480, no such passage occurs due to the check valve 482 being situated in line 480. Normally the manual override valve 424 is positioned so that any air in pilot line 428 is released to the atmosphere through vent line 425.

After the carriage assembly 90 is properly positioned within the ladle the main control valve 408 is shifted to provide air to the automatic line 414 and drain air in the manual line 412 through vent line 413. The air pressure in the automatic line 414 is controlled by the pressure regulator 474, a bypass line 478 with check valve 476 being provided in parallel to allow drainage of the automatic line 414 when the valve 408 is in a manual" position. For automatic operation, the main hoist valve 434 is placed in an up position and a pilot line 484 from line 480 provides air to release the brake 450 if the cable 86 is not slack. A pressure regulator 488 in line 480, controlled by the conveyor positioning mechanism 200 as described hereinabove, serves to provide air to the hoist 78. If the plunger 232 (see FIG. 4) is not depressed into the regulator due to the force exerted by spring 222 being greater than that exerted on the cam follower wheel 206, then no air is allowed to pass through the regulator to line 436 to actuate the hoist 78 to' raise the carriage assembly 90. Instead, since the brake 450 is released, the carriage assembly 90, and thus the conveyor assembly 146, will start to move downward along the elevator frame assembly 64. As the force on the cam follower wheel 206 forces the plunger into the regulator 488, air from line 480 is allowed to pass through the regulator to the main hoist valve 434 to actuate the hoist mechanism 78. As the hoist mechanism is actuated, the conveyor assembly 146 is raised, relieving the weight which the cam wheel 206 supports until the spring 222-forces the regulator plunger 232 out of the regulator 488 to stop the flow of air therethrough. The conveyor assembly 146 continues to oscillate, falling downward since the brake 450 is released and rising since the plunger 232 is inserted, until a balance of forces is maintained in which the conveyor assembly rests at the proper height. The air hoist 78 is periodically actuated as the cam wheel 206 rides on the spiraling courses of bricks built up in the lining 28 and thus this type of mechanism provides a self-regulating control of the height of the carriage assembly in the ladle 22. Alternatively, a limit switch could be used in place of the pressure regulator 488 if precise modulating control of the height of the platform is not required.

Air from the automatic line 414 is provided to the extension motor 162 by branch line 492 which connects to the line 458, the operation of the extension motor 162 being as previously described for manual operation with the valve 464 in an out position. Check

valves

490, 432, 494 and 456 are provided in

branch lines

480, 430, 492 and 415 respectively so that the air in these lines will not be released to the atmosphere during either automatic operation or manual operation. These check valves are necessary since both the automatic and manual lines are commonly connected to the branch lines 436 of the main hoist

valve

434 and 458 of the main conveyor extension valve 464.

With the conveyor assembly 146 properly positioned relative to the circumference of the ladle 22 and ready for operation to lay bricks, the boom mechanism 118 is operated to place bricks 144 on the conveyor chains 166. The stop-start switch 538 is then placed in a start position (as shown in FIG. 14B allowing air to pass between pilot lines 532 and 540) and the manual operator 500 on the front index switch 498 is actuated. Air passes from line 508 through the valve 498 to the pilot line 510 into chamber B of conveyor indexing valve 518 to switch valve 518 so that air passes from branch line 520 to return line 524 to retract the piston rod 194 of the indexing motor 192, air from the other side of the motor 192 being exhausted through extension line 522 and vent line 519. Pilot air from line 510 is also provided to chamber A of the brick aligner valve 544 by line 516 so that air from line 548 passes through valve 544 to line 550 to extend the piston rod 322 of the brick aligner motor 318 to align the bricks 144 on the chains 166. The piston rod 194 of the conveyor indexing motor 192 is retracted until the rod actuator 504 engages the operator of the rear indexing switch 530 to allow pilot air in line 528 to pass through valve 530 into pilot line 532. Pilot air is initially delivered to pilot line 528 from pilot line 508 via line 526 which passes through the brick limit switch 346 as long as a brick 144 does not engage the operator of the valve 346. The air in line 532 passes through the stop-start switch 538 into chamber A to switch valve 518 to extend the piston rod 194 of the conveyor indexing motor 192. At the same time, pilot air in line 532 is delivered by line 536 to chamber B of the brick aligner valve 544 causing the valve to change positions to retract the piston rod 322 of the brick aligner cylinder 318. The piston rod 194 is extended until the rod actuator 504 engages the operator 502 of the valve 498 to return the rod as previously described by manual actuation of operator 500.

This sequence of operation of advancing bricks 144 along the length of the conveyor assembly 146 continues until a brick 144 actuates the operator of the brick limit switch 346 to switch the valve 346 to pass air therethrough from line 526 to line 556. Pilot air is then delivered by line 558 into a chamber in valve 498 to actuate the valve 498 for returning the piston rod 194 in the indexing cylinder 192. However, when the rod actuator 504 engages the operator of valve 530, the valve 518 will not switch to extend the rod 194 until the brick 144 is removed to release the brick limit switch 346 since air is not then being delivered to line 528. As thus far described, each of the valves and

limit switches

498, 530 and 346 are provided with

vent lines

512, 531 and 554 respectively so that any air in the connecting lines is released to the atmosphere. This is necessary since the air in either chamber A or B of

valves

518 and 544, if not released, would oppose the air sent to the other of the chambers and would thus prevent switching of the

valves

518 and 544.

After a brick 144 has actuated the valve 346, the air in line 556 passes valve 257 of the brick pusher mechanism 236 which is actuated to allow air into line 564 only when the brick pusher mechanism is in a return position. The air in line 564 then passes to chamber B of the gripper control valve 568 to switch the valve to allow air to pass therethrough from line 506 to line 570. The air in chamber A of valve 568 is exhausted through vent line 601 via

lines

612, 602. From line 570, the air is delivered to the clamp cylinder 308 by line 580 which has a pressure regulator 586 positioned therein for controlling the clamping force applied by the motor 308 in order not to crush or crack the bricks grasped 1 by the

arms

272, 282. A bypass line 582 with check valve 584 is connected in parallel across the pressure regulator 586 to provide a quick exhaust of air from the clamp motor 308 when the signal is given to release the brick. Line 570 also delivers air to the rotary air motor 266 by line 572 to take the brick 144 from the chains 166 and place it in the wall of the ladle 22, the motion being clockwise as shown in FIG. 148. A check valve 576 in bypass line 574 is connected in parallel across a flow control valve 578 in line 572, the check valve 576 passing air quickly to the air motor 266 while preventing back flow therefrom and the flow control valve 578 controlling the air released from the air motor 266 during the return thereof to pick up another brick.

The air in line 570 also passes through the valve 354 located on the base of the connecting couple 68 of the elevator frame assembly 64 to control the operation of the

sprockets

288, 290 and chain 298 on the gripper arm 282. If the operator on the valve 354 has not been actuated, then air is delivered to line 588 to keep the piston rod extended in the air motor 294. Actuation of the operator on the valve 354 can best be seen in FIG. 13 wherein the upper platen 34 has rotated relative to the lower platen 32 such that the limit switch 354 is located adjacent to the cam trippers 356 supported by supports 358 from the bottom platen 32. As the upper platen 34 continues to rotate relative to the lower platen 32, the operator of the limit switch 354 will be depressed by the cam tripper 356 thus causing the valve 354 (see FIG. 14B) to shift positions so that air in line 570 is delivered to line 590. The air in line 590 passes through a flow control valve 594 to the air cylinder 294 to controllably retract the piston rod 296 as the

gripper arms

272, 282 rotate to lay a brick in the lining 28. A bypass line 596 with check valve 598 is provided in parallel to control valve 594 so that air will be exhausted quickly through line 590 to vent line 592 when the valve 354 is not actuated by the cam tripper 356.

As the

gripper arms

272, 282 rotate to deliver the brick 144 to the circumference of the ladle 22, the arm 282 engages and actuates a limit switch 306 as best seen in FIG. 6. Referring again to FIG. 143, when the limit switch 306 is actuated, air is provided from pilot line 600 to line 602 and, in turn, to

lines

612 and 604. Pilot air in line 604 enters chamber A of valve 566 to shift the valve to release the air in chamber B of valve 568 through vent line 567, and pilot air in line 612 enters chamber A of valve 568 to shift the valve 568 so air is supplied from line 506 to line 614. Flow control valve 606positioned in line 604 restricts the release of air from chamber A of valve 566 in order to provide a time delay before air may again be delivered to chamber B of valve 568 to cause actuation of the motor 266 to lay a brick. Bypass line 608 with check valve 610 is provided in parallel to the flow control valve 606 in order to effect a quick shifting of valve 566. The air in line 614 is passed to extend the piston rod of the clamp motor 308 to release the brick held thereby and is also sent, via branch line 620, to return the

brick gripper arms

272, 282 to pick up another brick 144. A bypass line 624 with check valve 626 is connected in parallel fashion across the flow control valve 622 in line 620 so that air will be quickly sent to the air motor 266 to return the

arms

272, 282, and will be released through the flow control valve 622 upon actuation of the air motor 266 to lay a brick. The pressure regulator 618 in line 614 is set so that only a small amount of air, which is all that is needed to effect the return of the brick gripper and release of the brick, is delivered to the air motor 266 and the clamp motor 308. A check valve 616 is placed in line 614 so as to allow a build-up of air on the return side of the motor 266 when laying a brick in order that the brick is not slammed into the lining. When the valve 568 is in the position shown in FIG. 14B, air in line 570 is released to the atmosphere by vent line 569.

Pilot line 602 also delivers air to chamber A of the brick pusher valve 628 to switch the valve to allow air to pass from line 630 into line 634 to the push side of the air motor 238, thus actuating the brick pusher mechanism 236 to push the brick 144 into place against the lastly laid brick in the lining 28. A pressure regulator 636 is provided in line 634 in order that the force of the brick pusher 236 does not become too great so as to crush bricks. Air in the return side of the motor 238 is quickly exhausted through vent line 629. As the brick pusher 236 is actuated, air is also sent to actuate the turntable air motor 60. Pilot line 644 continuously delivers air through the normally unactuated control valve 648 to line 652 into chamber A of turntable control valve 654 to force the valve into position to allow air to pass from line 662 into line 664, thereby actuating air motor to turn the turntable 30 clockwise. The valve 654 is a three-position air actuated, spring biased valve such that when air is not being continuously provided to chamber A or B, then the spring bias will force the valve 654 into a neutral position as shown in FIG. 148. The brick pusher mechanism 236 is more quickly actuated than the turntable air motor 60 since a flow control valve 670 is positioned in line 666 to controllably exhaust the air in the other side of the air motor 60 through the vent line 668. A bypass line 672 with check valve 674 is connected in parallel across the flow control valve 670 to allow air to pass quickly in line 666 to the counterclockwise rotation side of the air motor 60 if the valve 668 were in position to deliver air from line 662 to line 666.

The brick pusher 236 continues to rotate, due to actuation of both the

air motors

238 and 60, until the limit switch 261 is actuated, thus indicating occurrence of a predetermined amount of rotation which is sufficient to allow placement of the next brick in the lining 28. When this occurs, valve 261 shifts to allow air in line 638 to pass to line 642 into chamber B of valve 628 to switch the valve to return the brick pusher 236 to its return position. The air in chamber A is exhausted through vent line 601 of valve 306, the valve 306 being in its unactuated state since the gripper arms on the brick gripper 264 have returned to their return position. When the brick pusher valve 628 changes positions upon air entering chamber B, the air in line 634, and thus in line 644, is released to the atmosphere to the vent line 629. The valve 654 then returns to its neutral position due to the spring bias and also due to momentarily air being sent to chamber B by pilot line 646.

During operation of the brick gripper 264 and the operation of the brick pusher 236, the conveyor indexing mechanism 192 has been actuated (due to release of valve 346 when the brick gripper 264 picked up the brick 144) to deliver the next to be laid brick along the conveyor chains 166, thus actuating the valve 346 and sending air from line 526 to line 556. When the brick pusher 236 returns, valve 257 will be actuated and air will be delivered from line 556 to line 564 and another brick will be laid in place in the manner described above.

When initially orienting the conveyor assembly 146 relative to the circumference of the ladle 22, it may be necessary 'to actuate air motor 60 in order to turn the conveyor assembly. This is accomplished by placing the main control valve 408 in the manual position and using

push button valves

648 and 656. If the air motor 60 is to be operated to turn the turntable 30 clockwise, valve 648 is continually depressed to deliver air from lines 680, 676 to chamber A of valve 654. The operation for counter-clockwise rotation of the turntable 34 is accomplished by actuation of valve 656 in a similar manner to that done for clockwise rotation. Check

valves

682 and 684 are provided in lines 546 and 415 respectively so that air will not be fed into the manual line during automatic operation or fed into the automatic line during manual operation.

From the foregoing it is apparent that there is herein provided an automated bricklaying device 20 which permits the rapid buildup of the spiraling courses of refractory brick 144 necessary to form the working lining 28 ofa metal pouring ladle 22. The shell of the ladle 22 provides a circumferential guidance while the spiraling brick courses themselves provide the necessary height guidance so that the bricks are properly placed to form the working lining 28. A conveyor indexing mechanism 178 operates to deliver a series of refractory bricks 144 to the front of a conveyor assembly 146 wherein a brick gripper mechanism 264 grasps the bricks one at a time and lays them in the lining 28 of the ladle 22. A brick pusher mechanism 236 and a conveyor extension wheel 208 attached to the front of the conveyor assembly 146 ,serves to firmly secure and set each brick against the previously laid brick and causes actuation of a turntable motor to index the device 20 to the proper position for laying the next brick in the lining. During operation of the pushing cycle and indexing cycle, if it is desirous mortar may be provided to be placed in the working lining so as to ensure a proper seating and holding. of the bricks within the ladle.

It will be understood that various changes in the details, materials and arrangements of parts which have been herein described and illustrated in order to explain the matter of the invention may be made by those skilled in the art within the principle and scope of the invention as expressed in the appended claims.

What is claimed is:

l. A device for transferring an object at a first location in a first position to a second location in a second position comprising:

two spaced arms; arm rotating means for rotating said two spaced arms about a pivot axis; gripping means for each of said arms for picking up said object on a common axis therethrough, at least one of said gripping means being a rotating gripper rotatably mounted on one of said arms and adapted to impart rotation to said object upon rotation of said rotating gripper; and object rotating means for controllably rotating said objects relative to said arms including a sprocket mounted to said rotating gripper and rotatable relative to said one arm, a spring means on said one arm, a chain adapted to engage said sprocket and having one end fixed to said spring, and a mounting point to which the other end of said chain is fixed, said mounting point being positioned separate from said arms such that, upon rotation of said arms about said pivot axis, the distance along said chain between said sprocket and said mounting point changes, said spring means thereby changing length and said sprocket thereby rotating said rotating gripper to rotate said object from said first position to said second position as said arm rotating means rotates said arms from said first location to said second location. 2. The apparatus of claim 1 wherein said mounting point is movable relative to said pivot axis such that a first amount of rotation is imparted to said object as said arms rotate when said mounting point is in a first position and a second amount of rotation is imparted to said object as said arms rotate when said mounting point is moved to a second position.

3. The apparatus of claim 2 wherein said object rotating means further includes a second sprocket for said chain, said second sprocket being rotatably mounted separate from said arms such that the center of rotation of said second sprocket is positioned different from said pivot axis.

4. The apparatus of claim 3 wherein said object rotating means further includes a drive means to move said mounting point.

5. The apparatus of claim 4 wherein said arm rotating means is a rotary motor.

6. The apparatus of claim 5 wherein there is a reciprocal drive means for moving said spaced arms to grasp said object and for moving said spaced arms to release said object held thereby.

Claims

1. A device for transferring an object at a first location in a first position to a second location in a second position comprising: two spaced arms; arm rotating means for rotating said two spaced arms about a pivot axis; gripping means for each of said arms for picking up said object on a common axis therethrough, at least one of said gripping means being a rotating gripper rotatably mounted on one of said arms and adapted to impart rotation to said object upon rotation of said rotating gripper; and oBject rotating means for controllably rotating said objects relative to said arms including a sprocket mounted to said rotating gripper and rotatable relative to said one arm, a spring means on said one arm, a chain adapted to engage said sprocket and having one end fixed to said spring, and a mounting point to which the other end of said chain is fixed, said mounting point being positioned separate from said arms such that, upon rotation of said arms about said pivot axis, the distance along said chain between said sprocket and said mounting point changes, said spring means thereby changing length and said sprocket thereby rotating said rotating gripper to rotate said object from said first position to said second position as said arm rotating means rotates said arms from said first location to said second location.

2. The apparatus of claim 1 wherein said mounting point is movable relative to said pivot axis such that a first amount of rotation is imparted to said object as said arms rotate when said mounting point is in a first position and a second amount of rotation is imparted to said object as said arms rotate when said mounting point is moved to a second position.

5. The apparatus of claim 4 wherein said arm rotating means is a rotary motor.