US3110279A

US3110279A - Double ended work positioner

Info

Publication number: US3110279A
Application number: US751453A
Authority: US
Inventors: Jr Turner G Brashear
Original assignee: L AND B WELDING EQUIPMENT Inc
Current assignee: L AND B WELDING EQUIPMENT Inc
Priority date: 1958-07-28
Filing date: 1958-07-28
Publication date: 1963-11-12
Anticipated expiration: 1980-11-12

Description

1963 T. G- BRASHEAR, JR

DOUBLE ENDED WORK POSITIONER 4 Sheets-Sheet 1 Filed July 28, 1958 3 R n OR N Ta R H m mm 3 m a M f M, R 6 7 T w Nov. 12, 1963 T. a. BRASHEAR, JR 3,110,279

DOUBLE ENDED WORK POSITIONER 4 Sheets-Sheet 2 Filed July 28, 1958 INVENTOR 6. BRASHEAR, JR.

ATTORNEYS.

Nov. 12, 1963 BRASHEAIIR, JR 3,110,279

DOUBLE ENDED WORK POSITIONER Filed July 28, 1958 4 Sheets-Sheet 3 I INVENTOR 5 TURNER QBRA$HEAR,JR-

BY Y

ATTORNEYS 1963 T. e. BRASHEAR, JR

DOUBLE ENDED WORK POSITIONER 4 Sheets-Sheet 4 Filed July 28, 1958 INVENTOR TURNER 6. BRASHEAR, JR.

ATTORNEYS.

United States Patent 3,110,279 DGUBLE ENDED WGRK POSEIIGNER 'In ne r G. llrashear, in, El (Jen'ito, Galii, assignor to a ll: Welding Ec uipment, Ina, Berkeley, Calif., a corporation of Qalifornia riled July 28, 1953, Ser. No. 751,453 3 Claims. (1. 113-130) My invention relates primarily to the field of welding and more particularly to a work positioner for supporting work to be operated on.

Among the objects of my invention are:

t (1) To provide a novel and improved work posiloner;

(2) To provide a novel and improved work positioner having increased capacity for supporting work;

(3) To provide a novel and improved work positioner in which strains and stresses due to work loading may be partially or completely balanced;

(4) To provide a novel and improved work positioner having considerable flexibility as to adjustments;

(5) To provide a novel and improved work positioner which lends itself to continuous welding operatrons;

(6) To provide a novel and improved work positioner of comparatively light compact construction.

Additional objects of my invention will be brought out in the following description of a preferred embodiment of the same, taken in conjunction with the accompanying drawings, wherein:

FIGURE 1 is a front view in elevation of the work positioner of the present invention;

FIGURE 2 is a side view in elevation of the work positioner of FIGURE 1;

FIGURE 3 is a rear view in elevation of the central 9 portion of the positioner of FIGURE 1;

FIGURE 4 is a view in section taken in the plane i-".- of FIGURE 1;

FIGURE 5 is a fragmentary plan view looking down on the upward end of the positioner of FIGURE 1;

FIGURE 6 is a fragmentary side view in elevation of the right side of the work positioner of FIGURE 1;

FIGURE 7 is a view in section taken in the plane 7-7 of FIGURE 6;

FEGURE 8 is a viev. in section taken in the plane 83 of FIGURE 7;

FIGURE 9 is a detailed view of an angular adjustment for a Welding head in the Work positioner of FIGURE 1;

FIGURE 10 is a view depicting a detail of the structure of the present invention.

Referring to the drawings for details of my invention in its preferred form, the same comprises a frame 1 including a base 3, a pair of spaced columns 5, 7 anchored to and extending upwardly from the base and stabilized by a cross member 9 at the upper ends of the columns.

Spanning the upright columns is a mounting plate which is slidably supported on the columns by a pair of upper rollers 17 and a pair of lower rollers 19. The upper rollers are each disposed behind a column in proximity to an upper corner of the mounting plate, such roller being carried by a bracket 21 extending rearwardly from such mounting plate.

The lower rollers 19, on the other hand, are carried by brackets 23 on the mounting plate, in contact with the front edge of the columns.

The mounting plate 15 is formed with a central recess 29 in which to position a ball bearing assembly 31, the inner race of which constitutes a bearing sleeve 33 extending both to the front and to the rear of the mounting plate.

The mounting plate rollers 17 and 1-9 will be maintained in contact with the upright columns by the load carried arrears Patented Nov. 12, 1963 ice by the mounting plate, which in the present instance, will be the work supporting means 37. Such Work supporting means involves an elongated flanged housing 39 to the flanged end of which is afiixed a circular end plate 41 having a flanged central opening for assembly ove the exposed end of the bearing sleeve 33 and to which the ciroular end plate will be keyed.

Upper thrust rollers 47 carried by brackets 49 mounted on the front face of the mounting plate 15, bear against the front surface of the circular end plate 41 to hold the upper portion of this end plate against movement away from the mounting plate, while lower bearing rollers 51 mounted on the back of the mounting plate and protruding through slots in the mounting plate, engage the rear surface of the lower half of the circular end plate, and in cooperation with the upper bearing rollers '47, serve to maintain the circular end plate in a plane substantially paralleling the plane of the mounting plate 15 while still permitting rotation thereof.

Adjacent the opposite end of the elongated housing 39, a cross shaft 57 is journalled in opposing walls of the housing, and at each exposed end of this cross shaft is mounted a work supporting platform 59. Each such work supporting platform is preferably of disk shape and provided with a plurality of radial slots 61 for the mounting of work thereon.

From the foregoing construction, the work supporting means 37 involving the housing 39 and work supporting platforms 5% is capable of rotation as a unit, while the work supporting platforms are capable of rotation independently of the housing.

To ef ect rotational movement of the entire work supporting means, we provide a large diameter sprocket 65 on the rearwardly extending end of the bearing sleeve 33, this sprocket being connected by a drive chain 6-7 to a smaller sprocket 69 which is mechanically connected to the last stage of the gear reduction assembly 71 coupled to a suitable electric motor 73, the motor and reduction gear assembly being supported on a shelf 75 car ried by the mounting plate 15 on the rear side thereof.

The drive to the work supporting platforms 59 to effect rotation thereof independently of the housing, includes a separate drive motor 81 supported from a separate shelf 83 on the rear side of the mounting plate' A drive shaft 85 from this motor through the bearing sleeve 33, connects to a gear reduction assembly 87 mounted within the housing and terminating in a sprocket 89 which is connected by a chain 91 to a sprocket 93 mounted on the cross shaft 57.

An electrical ground is provided by a copper ring 9 5 held by a compression spring 95 against a metal disc 96 mounted on the shaft 57. The copper ring is connected to the housing 39 by a braided wire connection 97.

Elevational adjustment of the work supporting means 37 is accomplished through the raising and lowering of the mounting plate 15 which carries the work supporting means. For this purpose, I provide a drive motor 151 and reduction gear assembly which are installed on the second mentioned shelf 83 behind the mounting plate. This gear assembly terminates in a small sprocket 1&5 which is connected by a chain 167 to a larger sprocket 1%9 rotatably mounted on a stub shaft extending from the rear of the mounting plate, on which stub shaft is also mounted a small driven sprocket to obtain a further reduction in speed. A chain 115 is connected at one end to the cross beam '9 of the frame, and passing under this small sprocket 1.13 and over an idler sprocket 117 mounted on the rear of the mounting plate adjacent a vertical edge thereof, and anchored at its other end to a point lower down on the proximate column 7, will cause the mounting plate 15 to move up or down the columns, depending on the direction of rotation of the drive motor it'll associated therewith.

Overheat and extending transversely of the work supporting means 37 is an overhead track assembly 121 comprising a pair of brackets 123 each mounted at the upper end of one of the columns and extending from a point slightly to the rear of such column to a position above the work supporting means, and a track carried by such bracket at the forward ends thereof.

in the preferred embodiment of such track is a monorail preferably in the form of a length of pipe 125'. This track constitutes the sole support for a welding assembly 33-1 from which track the welding assembly is suspended.

The welding assembly 131 includes a carriage involving a pair of side panels 135 with each side panel formed so as to provide a forwardly extending upwardly di rected hook 137 which in turn is provided with a pair of angularly spaced rollers 139 enabling the carriage to be suspended from the rail in sliding engagement therewith.

Along the lower edge of each panel is a sleeve bearing 141. In the foreward end of each of these sleeve bearings there is slidably positioned an internally threaded sleeve 142. In the rear end of each bearing 141 is a ball bearing assembly 143. Threaded through each sleeve 142 is an adjusting screw 148, which at its rearward end is journalled in the ball bearing assembly 143 and extends sufiiciently beyond to mount a sprocket 144-. A chain 145 connects the two sprockets in a drive connection.

Carried by the sleeves 142 is a welding head subassembly including a pair of welding heads 1, slidably mounted on a pair of

slide rods

157, 159 which are anchored in and maintained in proper spaced relationship by end blocks .161, 163, each of which is fixed about the forward end of one of the internally threaded sleeves 142.

At a forward exposed end, one of the adjusting screws carries hand wheel 179, the rotation of which will, by reason of the chain drive connection, cause forward or rearward movement of the welding head sub-assembly, depending on the direction in which the hand wheel is rotated.

Extending between and journalled in the end blocks 161, 163, is a pair of spaced apart screws I85, 187. One of these screws passes through both welding heads but threadedly engages but one of them, while the other passes through both welding heads but threadedly engages only the other of the welding heads, whereby the rota- 'tion of one screw will horizontally shift its associated welding head along the slide bars in a direction depend ing upon the direction of rotation of such screw, while similar movements of the other welding head may be established by rotation of the other screw.

By simultaneously rotating both screws, simultaneous shifting movement of both welding heads may be realized. Whether such simultaneous movement involves movement toward or away from each other depends upon the relative direction of rotation of the two screws.

Rotation of the screws either simultaneously or one to the exclusion of the other and their relative directions of rotation are controllable by means of a drive motor 91 and intervening gear shift assembly 193. Toward this end, a. gear shift housing 195 is mounted adjacent the end block 163 and has a cover which may be provided with an integral mounting bracket for the drive motor 191.

The upper of the screws 187 has an unthreaded extension 199 which passes through the gear shift housing and terminates externally thereof in a worm gear 2&1 which meshes with a worm 2% driven by the motor 191, thus resulting in a direct drive connection from the motor to the upper of the screws.

Within the gear shift housing, this'extension =l9 of the upper screw has a gear 265 splined thereon.

The lower of the screws, 185, is similarly provided the present invention,

with an unthreaded extension 209 passing through the gear shift housing, and to the exposed end of this extension is afixed a hand knob 2.11 for manual rotation of the lower screw. Within the housing, this latter extension, like the one above, also carries a gear 213 splined thereto and in line with but not of suflicient diameter to mesh with that above it. Thus each of the threaded rods may be rotated independently of who other, the upper one by means of the motor 191 and the lower by means of the hand knob 211.

Loosely mounted on the upper extension 199; within the gear shift housing, is a gear shift in the form of a bell crank lever 219, one arm 221 of which extends up through arr opening in the housing (to provide a hand grip for shifting, while the other arm 223 is in the form of a plate on which are mounted two small meshing gears or pinions 225, 2-27. These are so disposed with respect to the splined gears 2595, 213 that in one position of the shift lever, only the gear 225 may be brought into mesh with the splined gears, while in another position of the shift lever, the splined gears may be coupled through both of the shift gears 22 5, 227 in series, while in an inter-' mediate or neutral position of the shift lever, neither of the shif gears will mesh with the lower splined gear.

Thus, in the first position mentioned, both

screws

185, 187 will rotate in the same direction, while in the second position referred to, these screws will rotate in opposite directions, while in the third or neutral position, only the upper screw will rotate. In ing head will be in use, while in the preceding positions of the gear shift, both welding heads will be in use, though in the one case they will move away from each other, While in the other case, they will be moving toward each other.

The hand knob 211 may be employed to adjust the starting position of one welding head with respect to the other and when such adjustment is being made, the gear shift will be in its intermediate or neutral position.

A latch pin arrangement 231 may be relied on to determine -the respective positions of the gear shift handle for l e various gear shifted operational adjustments mentioned.

Each of the welding heads involves a rear mounting section 237 for mounting the head on the slide rods and adjusting screws, said rear mounting section constituting a bracket to which a frontal section 239 may be supported for vertical adjustment in response to manual rotation of a control knob 241. I

The frontal section at its lower end terminates in a horizontal bearing 243 in which is journalled a holder 245 for the wire guide 247 of the head. Angular adjustments of the holder are. provided for by a lever 249 mounted at one end on the holder and connected at its other end to an adjusting screw 251 threadedly engaging a nut 253 mounted on the front surface of the frontal portion of the welding head.

The side panels of the welding assembly carriage are interconnected by a flux bin assembly constructed to provide two

hoppers

257, 259 for the holding of welding flux, with each hopper having a discharge spout connected by a flexible hose 261 to a welding head for depositing flux on the Work at the point of welding. A window 253 in each housing permits observation of the flux level therein.

Between the two hoppers, provision is made for supporting the electrical welding circuits and controls 267 which may be conventional, and when so located, are within easy reach of an operator in charge of the equip ment.

Extending rearwardly from the upper rear edge of the hopper assembly is a platform 269 which supports a pair of reels 271 of welding wire and a motor feed assembly 273 for each reel to feed the Wire to one of the welding heads through a guide sleeve 2'75 extending from the motor feed to the welding head.

the latter case, only one Weld- The contruction of the welding assembly including the carriage and the equipment carried thereon is such as to locate the center of gravity thereof to the rear of the monorail track 125 so that, when suspended from the track, the rear end of the platform 2.69 will pressure engage a rail 279 extending across and ahixed to the rear ends of the arms which support the monorail. Thus the welding assembly becomes stably positioned on the track merely by suspending the same therefrom, While at the same time leaving the welding assembly free for movement along the track, and to facilitate such movement, 1 prefer to interpose a roller or a plurality of rollers 281 bewteen the rear end of the platform and the rail engaged thereby.

Sliding adjustment of the welding assembly on the monorail is preferably manual, and an extremely simplitied and efficient control for such adjustment is provided for. This involves a sleeve type bearing 285 affixed to one of the panels constituting a side of the carriage, this sleeve carrying a shaft 287 which terminates at one end in a friction wheel 289 of rubber or the like in frictional engagement with the lower side of the monorail, while at its other end, the shaft carries a hand Wheel 29 Within convenient reach of an operator.

By pivotably mounting this sleeve bearing at one point 293 on the side panel and angularly adjusting the same at another point by a bolt connection 295 through an arcuate slot 297 in the side panel, the pressure between the track and the friction drive roller may be adjusted.

A stop pin 299 or the like provided at each end of the track, will protect the Welding assembly from running oif the track.

in utilizing the positioner of the present invention for welding purposes, both Work supporting platforms may be loaded with work to be welded. Under these conditions, the stresses and strains set up by the work on one of the supporting platforms will be balanced out by similar and corresponding stresses set up by the work on the otner platform. This becomes important in relieving the strains and stresses which in a conventional type positioner would be placed on the drive mechanism which adjusts the angular position of the platform.

With both work supporting platforms loaded, the Welding heads may be spaced so that the work on both platforms may be operated on simultaneously, or if the nature of work makes it desirable, both welding heads may be moved to one side of the machine for operation on the work on one of the supporting platforms. This may be desirable in refacing rollers or the like. While this is in process, the other platform may be made ready so that time lost may be reduced to a minimum.

it will be apparent from the foregoing that my invention, as illustrated and described, will fulfill all the objects of my invention, and While I have disclosed the same in its preferred form and in considerable detail, the same is subject to alteration and modification Without departing from the underlying principles involved, and I accordingly do not desire to be limited in my protection to the specified details so illustrated and described, except as may be necessitated by the appended claims.

I claim:

1. A double ended work positioner comprising a frame including a base, a pair of spaced upright columns anchored to said base and extending upwardly therefrom; a mounting plate spanning said upright columns; means slidably supporting said mounting plate to said upright columns; a housing having a circular plate at one end thereof, said circular plate having a bearing hole therein, a pair of work supporting paltforms, at oppositely disposed points of said housing adjacent the other end thereof to form an assembly; means rotatably mounting said housing and supporting platform assembly on said mounting plate, said rotatably mounting means including a bearing located in said mounting plate and having a bearing sleeve extending beyond both the front and rear surfaces of said mounting plate, said housing being assembled to said mounting plate with the front end of said bearing sleeve entering said housing through the bearing hole of said circular end plate, at least one bracket on the front surface of said mounting plate and overhanging the upper edge of said circular end plate and roller means carried by said bracket in engagement by said circular end plate, at least one bracket on the rear surface of said mounting plate in line with the lower portion of said circular end plate, and a roller carried by said last mentioned bracket, said last mentioned roller extending through a slot in said mounting plate for engagement by said circular end plate; means for rotatably adjusting said housing about its axis whereby to swing said Work supporting platforms to selected angular positions of adjustment; means for rotatably driving said work supporting platforms independently of said housing rotatable means; and means for adjusting the elevational position of said mounting plate on said upright columns.

2. A double ended Work positioner comprising a frame including a base, a pair of spaced columns anchored to said base and extending upwardly therefrom, and a cross beam interconnecting said columns at the upper ends thereof; a mounting plate spanning said upright columns; means slidably supporting said mounting plate to said upright columns, said means including a bracket extending rearwardly from each upper corner of said mounting plate, a roller carried by each of said brackets in contact with the rear side of the proximate column, and a roller carried by said mounting plate at each lower corner thereof and in contact with the front side of the proximate column; an elongated housing having a circular plate at one end thereof, said circular plate having a bearing hole therein; a pair of work supporting platforms; means rotatably mounting said work supporting platforms at oppositely disposed points of said elongated housing adjacent the other end thereof, to form an assembly, said means including a shaft journailed in opposing walls of said housing at such oppositely disposed point, and a Work supporting platform affixed to each of the ends of said shaft; means rotatably mounting said housing and supporting platform assembly on said mounting plate, said means including a bearing symmetrically located in said mounting plate and having a bearing sleeve extending beyond both the front and rear surfaces of said mounting plate, said elongated housing being assembled to :sm'd mounting plate with the front end of said bearing sleeve entering said housing through the bearing hole of said circular end plate, a pair of brackets on the front surface of said mounting plate and overhanging the upper edge of said circular end plate and rollers carried by said brackets in engagement by said circular end plate, a pair of brackets on the rear surface of said mounting plate in line with the lower portion of said circular end plate and roliers carried by said last mentioned brackets, said last mentioned rollers extending through slots in said mounting plate for engagement by said circular end plate; means for rotatably adjusting said housing about its axis whereby to swing said work supporting platforms to selected angular positions of adjustment, said adjusting means including a drive motor mounted behind said mounting plate and a speed reduction drive connection from said motor to said bearing sleeve; means for rotatably driving said work supporting platforms independently of said housing to tating means, said platform rotating drive means including a drive motor mounted behind said mounting plate, a drive shaft jorunalled in said bearing sleeve and extending into said housing, a drive connection from said last mentioned motor to said drive shaft, a speed reduction gear assembly in said housing and coupled to said drive shaft, and a drive connection from said speed reduction gear assembly to said platform supporting shaft; and means for adjusting the elevational position of said mounting plate on said upright columns.

3. A double ended work positioner comprising a frame upright columns, said means including a bracket extending V rearwardly from each upper corner of said mounting plate, a roller carried by each of said brackets in contact with the rear side of the proximate columns, and a roller carried by said mounting plate at each lower corner thereof and in contact with the front side of the proximate colurnn; an elongate housing having a circular plate at one end thereof, said circular plate having a bearing hole therein; a pair of Work supporting platforms; means rotatably mounting said work supporting platforms at oppositely disposed points of said elongated housing adjacent the other end thereof to form an assembly, said means including a shaft journalled in opposing Walls of said housing at such oppositely disposed points, and a work supporting platform afiixed to each of the ends of said shaft; means rotatably mounting said housing and supporting platform assembly on said mounting plate, said means including a bearing symmetrically located in said mounting plate and having a bearing sleeve extending beyond both the front and rear surfaces of said mounting plate, said elongated housing being asesmbled to said mounting plate with the front end of said bearing sleeve entering said housing through the bearing hole of said circular end plate, a pair of brackets on the front surface of said mounting plate and overhanging the upper edge of said circular end plate and rollers carried by said brackets in engagement by said circular end plate, a pair of brackets on the rear surface of said mounting plate in line with the lower portion of said circular end plate and rollers carried by said last mentioned brackets, said last mentioned rollers extending through slots in said mounting plate for engagement by said circular end plate; means for rotatably adjusting said housing whereby to swing said work supporting platforms to selected angular positions of adjustment, said adjusting means including a drive motor behind said mounting plate and a speed reduction drive connection from said motor to said bearing sleeve; means for rotatably driving said work supporting platforms independently of said housing rotating means said platform rotating drive means including a drive motor mounted behind said mounting plate, a drive shaft ournalled in said bearing sleeve and extending into said housing, a drive connection from said last mentioned motor to said drive shaft, a speed reduction gear assembly in said housing and coupled to said drive shaft, and a drive connection from said speed reduction gear assembly to said platform supporting shaft; and means for adjusting the elevational position of said mounting plate on said upright columns, said means including a drive motor mounted behind said mounting plate, a driven sprocket rotatably mounted on the rear of said mounting plate at a location approximately on the center line of said mounting plate, an idler sprocket rotatably mounted on the rear of said mounting plate adjacent a vertical edge thereof, a drive connection from said last mentioned motor to said driven sprocket, and a sprocket chain anchored at one end to said frame cross beam, said chain extending under said driven sprocket, then over said idler sprocket and anchored at its other end to the proximate column at a point at all times below saididler sprocket.

References Cited in the file of this patent UNITED STATES PATENTS 897,808 Wolfensberger Sept. 1, 1908 1,702,835 Lindemann Feb. 19, 1929 1,891,140 Chapman Apr. 14, 1931 2,359,531) Rose Oct, 3, 1944 2,445,016 Bentley July 13, 1948 2,577,306 Browne Dec. 4, 1951 2,647,483 Price Aug. 4, 1953 2,664,843 Turner Jan. 5, 1954 2,680,182 Chambers June 1, 1954 2,783,531 Eisler Mar. 5, 1957 2,787,826 Aronson Aug. 4, 1957 2,835,964 Yarwood May 27, 1958 FOREIGN PATENTS 965,107 France Feb. 8, 1950 749,610 Great Britain May 30, 1956

Claims

1. A DOUBLE ENDED WORK POSITIONER COMPRISING A FRAME INCLUDING A BASE, A PAIR OF SPACED UPRIGHT COLUMNS ANCHORED TO SAID BASE AND EXTENDING UPWARDLY THEREFROM; A MOUNTING PLATE SPANNING SAID UPRIGHT COLUMNS; MEANS SLIDABLY SUPPORTING SAID MOUNTING PLATE TO SAID UPRIGHT COLUMNS; A HOUSING HAVING A CIRCULAR PLATE AT ONE END THEREOF, SAID CIRCULAR PLATE HAVING A BEARING HOLE THEREIN, A PAIR OF WORK SUPPORTING PLATFORMS, AT OPPOSITELY DISPOSED POINTS OF SAID HOUSING ADJACENT THE OTHER END THEREOF TO FORM AN ASSEMBLY; MEANS ROTATABLY MOUNTING SAID HOUSING AND SUPPORTING PLATFORM ASSEMBLY ON SAID MOUNTING PLATE, SAID ROTATABLY MOUNTING MEANS INCLUDING A BEARING LOCATED IN SAID MOUNTING PLATE AND HAVING A BEARING SLEEVE EXTENDING BEYOND BOTH THE FRONT AND REAR SURFACES OF SAID MOUNTING PLATE, SAID HOUSING BEING ASSEMBLED TO SAID MOUNTING PLATE WITH THE FRONT END OF SAID BEARING SLEEVE ENTERING SAID HOUSING THROUGH THE BEARING HOLE OF SAID CIRCULAR END PLATE, AT LEAST ONE BRACKET ON THE FRONT SURFACE OF SAID MOUNTING PLATE AND OVERHANGING THE UPPER EDGE OF SAID CIRCULAR END PLATE AND ROLLER MEANS CARRIED BY SAID BRACKET IN ENGAGEMENT BY SAID CIRCULAR END PLATE, AT LEAST ONE BRACKET ON THE REAR SURFACE OF SAID MOUNTING PLATE IN LINE WITH THE LOWER PORTION OF SAID CIRCULAR END PLATE, AND A ROLLER CARRIED BY SAID LAST MENTIONED BRACKET, SAID LAST MENTIONED ROLLER EXTENDING THROUGH A SLOT IN SAID MOUNTING PLATE FOR ENGAGEMENT BY SAID CIRCULAR END PLATE; MEANS FOR ROTATABLY ADJUSTING SAID HOUSING ABOUT ITS AXIS WHEREBY TO SWING SAID WORK SUPPORTING PLATFORMS TO SELECTED ANGULAR POSITIONS OF ADJUSTMENT; MEANS FOR ROTATABLY DRIVING SAID WORK SUPPORTING PLATFORMS INDEPENDENTLY OF SAID HOUSING ROTATABLE MEANS; AND MEANS FOR ADJUSTING THE ELEVATIONAL POSITION OF SAID MOUNTING PLATE ON SAID UPRIGHT COLUMNS.