US2323088A - Mechanical arm - Google Patents

Description

N. F. FONER MECHANICAL ARM June 29, 1943.

Filed Dec. 28, 1940 -5 Sheets-Sheet 2 June 29, 1943. N FONER 2,323,088

MECHANICAL ARM Filed Dec. 28, 1940 5 Sheets-Sheet 3 lizveizzar: Warm/v F F /VEB,

N. F. FONER MECHANICAL ARM Filed Dec. 28, 1940 June 29, 1943.

5 Sheets-Sheet 4 NEWTON F FOA E/Q June 29, 1943. Q N, F. FONER I 2,323,088

MECHANI CAL ARM Filed Dec. 28, 1940 5 SheetsSheet 5 Patented June 29, 1943 I UNITED STATES PATENT orrics- 2,323,088 MECHANICAL ARM Newton F. Foner, Pittsburgh, Pa. Application December 28, 1940, Serial No. 372,130

11 Claims.

This invention relates to an improved apparatus and method for automatically handling material with safety, particularly very heavy pieces of metal at high temperatures, as a continuous series of operations and movements without requiring the intervention of Judgment or manual skill on the part of the operator, after the first of a series of steps and coordinated movements have been initiated. It relates more particularly to a device in the nature of an automatic mechanical arm and load handling mechanism by means of which an object may be engaged, automatically lifted to a position for safe transport from one location, and transported and discharged at a predetermined second location, I

In manufacturing operations, it is frequently necessary to transport heavy workpieces from one processing location to another. Plant layout arrangements and building construction often cause such locations to be congested or in closely restricted spaces such that the usual crane facilities cannot be employed.

This is particularly true in steel mill plant layout and operations which involve the placement of heavy processing machinery, i. e., rolling mills, shears and conveyor tables, in close proximity, in operating upon objects having large mass, great weight, and, at times, high temperatures involved. When such objects are processed at elevated temperatures, their handling becomes I more diflicult due to the safety hazard considerations which must be observed for the safety and protection of the workmen, as well as the mechanical and physical problems incident to the time and temperature factors involved.

For example, in the production of steel slabs feet in width by a rolling operation, it is necessary, from time to time, to obtain a transverse test piece of the hot rolled slab for analytic testing. Accordingly, a test piece, having dimensions of about 8" x 8" x 60" and a weight of about 1000 pounds is sheared from the end of a hot rolled slab, at a temperature of about 1600" F. (870 C.) and this test piece, after being removed from the rolling and shearing location, is allowed to cool and then subjected to various tests.

Due to the conventional close proximity of the shear to the slab conveyor table and to the lack of overhead clearance, it is impossible to utilize crane or other conventional facilities for rapidly engaging, removing, transporting and discharging this heavy mass of hot metal. It is, therefore, necessary to design a device for this purpose. This invention involves the problem of providing a means for handling a test piece of the 55 of above character under the conditions stated in a humanly efficient and eflective manner.

It is understood, however, that the use and employment of the invention is not limited to test pieces, but may have other applications without change in different environment or by making such changes in detail within the competence of those skilled in the art without departing in essential respects from this invention.

It is the primary object of my invention to provide a new and improved method and an automatic mechanism which may be used flexibly, in closely confined or recessed spaces, and adjacent obstructions, to receive and transfer heavy objects rapidly and safely to a second predetermined location.

It is another object of my invention to provide a mechanism and method which, by use of a single prime mover will, after the initial start, automaticallyprovide several and various types of correlated steps, functions and transporting motions without the necessity for control or intervention of the judgment or skill of the operator in transport between two stations.

These and other objects of my invention will become apparent from a consideration of the following specification when considered in coniulililctilon with the accompanying drawings, in w c Figure 1 is a plan view of the specimen handling arm, showing its general relation to surrounding restricting and intervening obstructing apparatus, and indicating the path traversed by the arm in transporting a massive and heavy red hot transverse test piece which has been sheared off, to a station where it may be handled for various test purposes;

Figure 2 is a sectional elevation taken on the line and looking in the direction of the arrows II-II of Figure 1, showing the master cam in section, in load receiving relation with a cam lever, and showing in phantom dot and dash line the closely adjacent apparatus surrounding the sheared test piece, and also showing the pusher arm for moving the test specimen upon the work or load carrier at the end of the transporting arm;

Figure 3 is a vertical section showing the arm and its method of support and the drive means actuating the work or load handling head at the end of the arm, and also the drive means for moving the main girder arm; the relative position the adjacent apparatus which hedges in and in adapting it thereto, I

renders diflicult the handling of the test piece is indicated in phantom dot and dash position;

Figure 4 is a sectional assembly of the master cam and pivoted lever cam showing the shock absorber, and the work or load receiving head in position for receiving the test specimen as it is pushed from the table of the shearing machine by the pusher bar. The successive positions or path of travel of the test piece is indicated by the dotted line positions of the test piece and, by the path indicated by the arrows on the dot and dash line, as the main girder arm is rotated and is accompanied with simultaneous change in the relation of the coacting faces of the master cam and the cam face of the pivoted lever cam, which raises the work holder at the end of the lever cam and causes the work specimen to be securely and safely retained in position on the work head or load carrier which has been moved to a position where its sides form a valley-like gutter or pocket. In this position the initial movement of the coacting cam and cam lever has been such that they occupy the relative positions as shown in the dotted line position to the rightof Figure 4;

Figure 5 is a view on reduced scale similar to Figure 4 but showing the work' carrying head and the cam faces of the cam and lever cam in two different positions corresponding to the two positions of the load carrying arm, the dotted line position representing the raised carrying position of the arm, and the full line position representing the load dumping or releasing position at the end of the travel of the main girder arm at its limit of travel at the second station; and

Figure 6 is a vertical section showing the fixed post and the outer telescoping rotatable column or post, together with its means for rotatably supporting the same at top and bottom and showing the worm and gear driving connection.

Before starting a detailed description of the method and apparatus comprising the subject matter of this invention, general reference will be made to the surrounding apparatus and mechanism which is immediately adjacent the load to be transported, the transversely sheared test piece in this illustrative instance and other mechanism which is disposed in the environs between the two fixed predetermined stations. As before stated, it is such a crowded and congested disposition of apparatus adjacent the load to be transported which makes it difilcult, if not impossible, to employ the usual and conventional means and mode of effecting material transportation between two predetermined points, such for example as by cranes, conveyors, chutes and the like.

Throughout the drawings the appurtenant environmental apparatus forming no immediate or primary part of this invention is represented in a phantom-like manner by dot and dash line.

In the drawings the apparatus shown by dot and dash line includes the following-the shear blades SB, the shear housing SH, and the pusher arm PA for pushing the sheared hot metal test piece from the shear table ST onto the horizontal base or floor of the load receiver LR. The roller conveyor RC having the adjustable guards AG serves as a means of conveying the large hot metal slab MS to and from the shears. The operator for the shear control mechanism is in the. control room CR located between the two stations. The gage is indicated as G (see Figure 2). The general 90 path of movement followed by the arm is indicated by the curved dash line and arrows in Figure 1, and is designated travel of arm.

Other conventional representations in Figure 1 are the motor M, speed reduction mechanism SR, brake Br, coupling C and a conventional or well known type of limit switch LS which serves to automatically stop the arm at the limits of travel in each direction. The cam mechanism later to be described, serves as the mechanical means which automatically controls and determines the predetermined points or positions in the path of travel of the girder arm ill from one station to the other at which the load receiver LR shall be at any one of three different heights for either First, the load or slab receiving position (the intermediate position as to height-see Figures 1', 2, 3 and a);

Second, the raised position during movement or transport from one station to the other (see the dotted line position of Figures 4 and 5) and Third, the lowest position for discharge of the test slab at the second station for test purposes.

In view of the fact that mechanical actuation of the automatic cam control mechanism is directly dependent upon relative rotation of arm, relative a stationary member (more fully considered at a later point) the general system embodies a combination electromechanical method of automatic control, which eliminates the necessity for judgment and manual skill and dexterity in a series of steps and operations in transporting the load between two predetermined stations.

In the selected embodiment chosen for purposes of illustration, the L -shaped receiver LR is shown as comprising a horizontal platform and vertical back portion, angularly disposed in substantially normal relation to each other (see Figures 2, 4 and 5). At the first load receiving station the load receiver LR is brought to a position in which the horizontal platform portion of the load receiver LR is aligned with shear table ST on which the sheared test specimen slab TS is resting. The pusher arm PA (actuated in a manner not necessary to disclose herein) moves the test specimen upon the horizontal platform portion of the load receiver LR which is mounted at th end of a pivoted carrier arm, generally identified as l0, and to be hereinafter more specifically described. It is understood that other types of load carriers may be employed, better suited to th character of the load, if the nature of the load is modified or the method or apparatus is used for other purposes in diilerent environment.

In the preferred form shown in the drawings, the main girder portion ll of the transporting arm is mounted intermediat it ends, in rigid relation, by any suitable construction, with the upper end of the hollow post Ila, and is horizontally rotatable with the hollow post l'la, about a fixed vertical shaft I! (Figure 6) and, simultaneously, the carrier Ill is rotatable about the pivot l3 to elevate the load carrier LR so that its L-shaped receiving position is changed to a V-shaped transporting position. The resultant of the simultaneou horizontal and elevating motions is a parabolic motion (see Figures 2 and 4) away from the shear which clears the various obstructions between this point and the point of delivery of the test piece. The elements, by means of which this result is accomplished, will now be described.

.A structural steel platform generally identified as ll (see Figures 3 and 6), supported upon a.

concrete foundation, provides a mounting for a geared reversible motor M having dynamic braking arrangements and a pair of limit switches LS (see Figure l). The vertical main shaft I2 is fixed to the platform 14 and carries at its lower and upper ends bearing housings II which encircle the fixed shaft I2 (see Figure 6). The lower bearing housing I1 carries a worm gear I3. A worm shaft I 9 provided with a worm 26 is connectedwith the reversible motor M through a flexible coupling C (Figure 1) and being engaged with the worm gear It operates to turn the arm girder II horizontally, either clockwise or anticlockwise about the fixed shaft I2. The bearing housing I1, I1 spaced widely apart along the fixed post I2, contributes greatly to the stability and support of the fixed and varying loads.

At its upper end (see Figures 1, 3 and 6), the vertical fixed shaft I2 carries a fixed (dead) bevel gear 22 and is held to the arm girder I I by the bearing housing '23. A keyed shaft 24 supported in a bearing 25 in the bearing housing 23 and mounted upon the horizontal portion of the arm girder II, at its inner end, carries a bevel pinion 26 which meshes with the fixed bevel gear 22 and also carries at its outer end a bevel gear 21 (Figures 1 and 3). A shaft 29 mounted upon the inclined portion of the arm girder II carries, at its upper end, a bevel gear 29 and at its lower end a bevel gear 39 (see Figures 1 and 3).

At its outer end, arm girder II terminate in a horizontally extending portion upon which is mounted a cam shaft 3| (see Figure 3). This cam shaft carries, at its inner end, a bevel-gear 32 and, at its outer end, a cam 33 havingworking cam faces 33, 33, 33 and 33 of special design which cooperate with cam faces 34, 34 of lever cam 34. The lever cam 34 is pivoted at I3 and press fitted at the end 34. (Figure 4) to a bushing 36 which constitutes the cylinder 31 (Figures 1, 2, 4 and 5) of a shock absorber assembly designed to provide for a light contact of the forward edge of the test piece carrier I0 with the delivery side of the shear table ST without damage due to overtravel of the arm or to overpushing of the test piece by the pusher arm PA.

The upper end of the test piece carrier I0 constitutes the plunger 38 (Figure 4) which operates in the cylinder 31. This plunger 38 is provided with a transverse slot 39 to accommodate a pin 43 which is positioned and fixed horizontally in the side wall of the cylinder 31. A compression spring 4| is disposed within the cylinder 31 between the lower end 34 of the lever cam 34 and the upper end 33 of the test piece plunger 38.

The operation of the mechanism is as follows:

The motor M acting through a conventional gear reduction unit SR turn the worm and worm shaft I9 (see Figures 1 and 6). The latter being engaged with the worm gear I3 causes the bearing housing I1 and hollow post H to rotate. The arm girder II keyed to the worm gear I3 is caused to rotate through the hollow post surrounding the fixed main vertical shaft I2. 7

When the arm girder II is caused to rotate through the upstanding hollow post or columnar post I1, the bevel pinion 26 mounted upon the girder and engaged with the fixed bevel gear 22 is likewise caused to rotate. The shaft 24 upon which the bevel pinion 26 is keyed is rotated by this bevel pinion 26 and the rotation is communicated through bevel gears 21, 29, 36 and 32 to the cam shaft 3| and thence to cam 33 which cooperates with lever cam 34 to elevate and to lower the test piece TS on the carrier II.

Prior to the shearing of the desired test piece TS by the shear blades SB, the mechanical arm assembly is positioned as shown in Figures 1, 2 and 3, the forward edge of the test piece carrier or load receiver LR abutting the delivery side of the shear table ST. Owing to the provision of the shock absorber assembly, the operator located in the pulpit may quickly and safely move the ponderous mechanism to this position without the exercise of undue skill in this operation. After the test piece has been sheared, the pusher arm PA is operated to move the piece forward onto the carrier III (see Figure 3). The motor M is then operated to begin rotation of the arm girder II. By its initial movement, this arm causes rotation through the medium of bevel gears 22, 26, 21, 29, 30 and 32 of the cam 33. Cam 33 has a working face portion 33 (see Figur 4) for elevating the loaded carrier LR, a portion 33 for the elevated transfer motion of the loaded carrier, and a portion 33" for lowering the loaded carrier to the desired level at a delivery point. If the initial movement of the arm girder I I is, for example, in a clockwise direction (see Figure 1), the portion 33 of cam 33 will cooperate with the working face 34 (see Figure 4) of the lever cam 34 to elevate the carrier III. The cam face portion 33 has a contour such as will give a rapid elevating movement during the initial 5 of rotating travel of the arm II. The parabolic path thus described by the carrier as the resultant of its two motions, elevating and horizontally rotating (see Figures 2 and 4) is such as will permit the extraction of the test piece from the closely confined spaces in the vicinity of the shear.

At such time as these two movements have progressed sufiiciently to clear obstructions adjacent the shear, the rotation of cam 33 has progressed so that transfer portion 33 thereof is in cooperation with the lever cam face 34 to maintain the carrier III in its elevated position until it nears the delivery point. At the time the carrier approaches this point, the cam 33 has progressed so that its lowering cam face 33 is in cooperation with the lever cam face portion 34. As the cam surfaces in contact progress through the lowering motion, the test piece TS is subjected to a rapid dumping action.

Reversal of the motor M causes a reversal of these actions and the test piece carrier I0 may be returned to its original loading position or, if desired, it may be arrested at some mid-point to permit production shearing of the test piece slab lengths in the conventional manner.

To prevent overtravel of the arm mechanism at either the loading or the delivery point, limit switches LS, operated by the gear reduced drive GR (see Figure l) of the main motor, are employed. With conventional speeds employed in the drive motor and in gear reduction, the overtravel of the arm girder may be held to a maximum value of a few degrees of arc.

Counterbalance weights are employed on the rotating girder arm (arranged in any suitable manner thereon) on the end thereof which extends on the side of the central axis about which the girder arm II rotates; this would be the fixed post I2 and the hollow rotating post I1. Such counterbalance materially reduces and minimizes the turning moments in a vertical plane of theloaded girder arm as carried to the bearings I1 at top and bottom of the posts I2 and I1.

Such counterweight may be varied with loads and the degree of loaded or unloaded counterbalance desired.

From the foregoing description, it should be apparent that my invention provides an automatic mechanism which may be used flexibly, in closely confined spaces and between obstructions. to receive heavy industrial loads at one point and to transfer and deliver them to a sec-- and point rapidly and safely.

I claim:

1. A mechanical arm including a base, a fixed post, a fixed bevel gear mounted at the upper end of said post and held against rotation, a hollow post rotatably mounted and surrounding the fixed post, a bevel gear pinion rotatably mounted on said hollow post and meshing with said fixed bevel gear whereby said bevel pinion isrotated upon rotation of said hollow post, means for rotating said hollow post, a girder arm rigid with said hollow post and extending outward to one side of said hollow post from the upper end thereof, a load supporting arm pivotally carried at the end of said girder arm and extending outward to one side of said girder arm, actuating means for raising andlowering said pivoted load carrying arm in predetermined timed relation at predetermined points to any one of a number of positions and for predetermined periods in the path of movement of said girder arm between stations, said actuating means for said pivoted load supporting arm including a driving connection between the fixed post and the hollow rotatable positively driven post and dependent upon relative movement between the fixed post and the rotatable positively driven post for the actuating means and driving connection for effecting and controlling the movement and position of said pivotally supported load carrier arm.

2. Amechanical arm including a base, a fixed post, a fixed bevel gear mounted at the upper end of said post and held against rotation, a hollow' post rotatably mounted and surrounding the fixed post, bearings between said fixed and rotatable posts at the upper and lower portions thereof for rotatably supporting said hollow post, a bevel gear pinion rotatably mounted on said hollow post at the upper end thereof and meshing with said fixed bevel gear whereby said bevel pinion is rotated upon rotation of said hollow post, means for rotating said hollow post including a worm and gear drive at the base of said post, a girder arm in rigid relation with said hollow post and extending outward to one side of said hollow post from the upper end thereof and means thereon adapted to support and transport a load at the end thereof, said means including a load supporting arm mounted for pivotal movement about a line extending radially of the axis about which th main girder arm rotates and in a transverse plane substantially normal to said radial line, actuating means for controlling movement of said pivoted load carrying arm to any one of a number of positions including load receiving position, safety transport position, and unloading position at predetermined points in the path of movement of said girder arm between stations, said actuating means for said pivoted load supporting arm including cam mechanism and driving mechanism therefor arranged between said rotatably mounted bevel gear and said pivoted load carrier arm.

3. A mechanical arm including a base, a fixed post, a fixed bevel gear mounted at the upper end of said post and held against rotation, a hollow post rotatably mounted and surrounding the fixed post, bearings between said fixed and rotatable posts at the upper and lower portions thereof for rotatably supporting said hollow post, a bevel gear pinion rotatably mounted on said hollow post at the upper end thereof and meshing with said fixed bevel gear whereby said bevel pinion is rotated upon rotation of said hollow post, means for rotating said hollow post, a girder arm in rigid relation with said hollow post and extending outward to one side of said hollow post from the upper end thereof and means thereon adapted to support and transport a load at the end thereof, said means includin a load supporting arm pivotally carried at the end of said girder arm and extending outward to one side of said girder arm,

actuating means for raising and lowering said pivoted load carrying arm toany one of a number of positions in the path of movement of said girder arm between stations, said actuating means for said pivoted load supporting arm including cam mechanism and driving mechanism therefor arranged between said rotatably mounted bevel gear and said pivoted load carrier arm, said cam mechanism including a cam drum and a cam face on said pivoted load receiving arm, said cam drum and .cam face on said pivoted arm having their respective cam faces so arranged and disposed as to move the load receiver into three different elevations, in succession as the girder arm is rotated from one station to the other.

4. A mechanical arm including a base, a fixed post, a fixed bevel gear mounted at the upper end of said post and held against rotation, a hollow post rotatably mounted and surrounding the fixed post, bearings between said fixed and rotatable posts at the upper and lower portions thereof for rotatably supporting said hollow post, a bevel gear pinion rotatably mounted on said hollow post and meshing with said fixed bevel gear whereby said bevel pinion is rotated upon rotation of said hollow post, means for rotating said hollow. post, a girder arm in rigid relation with said hollow post and extending outward to one side of said hollow post from the upper end thereof, a load supporting arm mounted for pivotal movement in a transverse plane substantially normal to said radial line, actuating means for raisin and lowering said pivoted load carrying arm, cam mechanism and driving mechanism therefor arranged between said rotatably mounted bevel gear and said pivoted load carrier arm, said cam mechanism includingfa cam drum rotatably support at the end of the girder arm and a cam face on said pivoted load receiving arm, said cam drum and cam face on said pivoted arm having their respective cam faces so arranged and disposed as to move the load receiver into three difierent elevations in succession as the girder arm is rotated from one station to the other, said three positions including first an intermediate height at a load receiving position adjacent the shear slab table in which position the base of the load receiver is substantially horizontal, second.

a top elevated transporting position in order to I port a heavy load at the end thereof, a base, a fixed post, a fixed bevel gear mounted at the upper end of said post and held against rotation, a hollow post rotatably mounted and surrounding said fixed post, a girder arm fixed intermediate its ends in rigid relation with the upper end of said hollow post, bearings between said fixed and rotatable post at the upper and lower portions thereof for rotatably supporting said hollow post, a bevel gear pinion rotatably mountedon said girder arm and meshing with said fixed bevel gear, whereby said bevel pinion is rotated upon rotation of said hollow post, and means for rotating said hollow post including a worm and gear drive at the base of said post.

6. A mechanical girder arm adapted to transport a heavy load at the end thereof, including, a base, a fixed post, a fixed bevel gear mounted at the upper end of said post and held against rotation, a hollow post rotatably mounted and surrounding said fixed post, a girder rigid with the upper end of the hollow post, bearings between said fixed and rotatable post at the upper and lower portions thereof respectively, for rotatably supporting said hollow post and resisting the turning moments about said fixed Post in a substantially vertical plane resulting from the heavy load at the end of the girder arm, a bevel gear pinion rotatably mounted on said girder arm and meshing with said fixed bevel gear whereby said bevel pinion is rotated upon said hollow post,

and means for rotating said hollow post.

'7. A mechanical arm including a fixed post and base, a fixed bevel gear mounted at the upper end of said post and held against rotation, a hollow post rotatably mounted and surrounding the fixed post, bearings between said fixed and rotatable posts at the upper and lower portions thereof for rotatably supporting said hollow post, a bevel gear pinion rotatably mounted on said hollow post and meshing with said dead fixed bevel gear, means for rotating said hollow post, a girder. arm in rigid relation with said hollow post and extending outward to one-side of said hollow post from the upper end thereof, and means thereon adapted to support and transport a load at the end thereof, said means including a load supporting arm pivotally carried at the end of said girder arm, actuating means for controlling movement of said pivoted load carrying arm, and cam mechanism including driving mechanism therefor arranged between said rotatably mounted bevel gear and said pivoted load carrier arm.

10. Apparatus as defined in claim 7, including shock absorbing means for said pivotally supported load carrier arm interposed between the point oi pivotal support and the load carrier at the end of said arm. said shock absorber including a cylindrical housing, a plunger slidable therein, and a cushioning means interposed between one end of the cylinder and the movable plunger, a stop limiting the outward movement of said plunger, said cushioning means being normally 'eifective to urge the plunger outward against said limiting stop, whereby contact of the load carrier with an obstructing object causes compression of the cushioning means.

11. Apparatus as defined in claim 3, in which the relation between the coacting cam surfaces is such that when the load carrier end of said pivoted carrier arm is in its highest position said arm will assume a substantially horizontal position, whereby any substantial downward and outward thrust of, the plunger is eliminated or minimized during transport of the load.

NEWTON l".

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