US3081890A

US3081890A - Material handling machine

Info

Publication number: US3081890A
Application number: US178531A
Authority: US
Inventors: Daniel M Schwartz; Theodore N Hackett; Laurette C Mccallum
Original assignee: Eimco Corp
Current assignee: Eimco Corp
Priority date: 1962-03-07
Filing date: 1962-03-07
Publication date: 1963-03-19
Anticipated expiration: 1980-03-19

Description

March 1963 D. M. SCHWARTZ ETAL 3, 0

MATERIAL HANDLING MACHINE 7 Sheets-Sheet 1 Original Filed March 29, 1955 DA NIEL M .SCHWARTZ THEODORE N. HACKE TT, DUNCAN l. McCALLUM March 1963 D. M. SCHWARTZ ETAL 3,

MATERIAL HANDLING MACHINE Original Filed March 29, 1955 '7 Sheets-Sheet 2 :f I24 I30 "2 II I53" I22 I30 I34 I20 I H8 I25 "6" 5 I l i 5 if z 1 I26 IIO r i Z i i g I I48 I40 I42 [54 IN VENTORS DANIEL M SCHWARTZ THEODORE N.HACKET'T, DUNCAN I. McCALLUM ATTORNEY March 1963 D. M. SCHWARTZ ETAL 3,

MATERIAL HANDLING MACHINE 7 Sheets-Sheet 3 Original Filed March 29, 1955 m! w! v2 3mm DANIEL M. SCHWARTZ THEODORE N. HACKET'T,

DUNCAN I. McCALLUM. i M TM March 1963 D. M. SCHWARTZ ETAL 3,

MATERIAL HANDLING MACHINE Original Filed March 29, 1955 '7 Sheets-Sheet 4 awe/Mow DANIEL M.SCHWARTZ THEODORE N.HACKETT, DUNCAN I. MCCALLUM.

e AMQ/ TM March 1963 D. M. SCHWARTZ ETAL 0 MATERIAL HANDLING MACHINE 7 Sheets-Sheet 5 Original Filed March 29, 1955 INVENTOR$ DANIEL M. SCHWARTZ THEODORE N. HACKETT, DUNCANII. McCALLUM. BY /MW ATTORNEY March 19, 1963 D. M. SCHWARTZ ETAL 3,081,890 MATERIAL HANDLING MACHINE Original Filed March 29,

ts-Shee 6 Ire INVENTORS DANIEL M. SCHWARTZ. THEODORE .HACKETT, DUNCAN LMgCALLUM.

ATTORNEY March 19, 1963 D. M. SCHWARTZ E TAL 3,081,890

MATERIAL HANDLING MACHINE '7 Sheets-Sheet '7 Original Filed March 29, 1955 wmm NNNJ mom ONN mmm

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INVENTORS DANIEL M. SCHWARTZ THEODORE N. HACKET l. Mc CALLUM DUNCAN BY A/M 7.14M

ATTORNEY United States Patent 3,681,890 MATERIAL HANDLING MACWE Daniel M. Schwartz and Theodore N. Hackett, Sait Lake City, Utah, and Duncan I. Me'Callum, deceased, late of Mud Lake, Idaho, by Laurette C. Metlallum, administratrix, Montreal, Quebec, Canada, assignors, by mesne assignments, to The Eimeo (Importation, Salt Lake City, Utah, a corporation of Delaware Continuation of application Ser. No. 497,754, Mar. 29, 1955. This application Mar. 7, 1962, Ser. No. 178,531 7 Claims. (Cl. 214-131) This invention relates to a mobile material handling machine that is characterized by its compactness, mobility and ease of control. The invention will be particularly described with reference to such a machine including an overhead bucket supported on a main frame having individually operated crawlers or self-laying tracks.

This application is a continuation of our copending application Serial No. 497,754, now abandoned.

It is an object of the invention to provide such a machine having a centrally positioned prime mover, with a rear power take-off connected to a material handling structure actuating mechanism.

A further object is to provide a bucket transmission which is of the constant mesh hydraulically controllable type.

Another object is to provide such a device having an overhead bucket material handling means wherein the overhead bucket mechanism is automatically disconnected from the power supply and its travel reversed and/or stopped at substantially any predetermined bucket position whereby the discharge distance of the bucket may be readily controlled.

Another object is to provide brake mechanism for the overhead bucket material handling device which is automatically applied and prevents further travel of the bucket when the bucket control lever is released intentionally or accidentally.

A further object is to provide a two-speed drive mechanism for the overhead bucket device whereby extremely high digging force may be obtained in a low gear position, and high speed material discharge may be obtained in the high speed gear position.

These and other objects and advantages of the invention will appear more clearly from the detailed description in conjunction with the illustrative embodiments shown in the accompanying drawings in which:

FIG. 1 is a right front perspective view of the overhead material handling machine of the invention with the cab and the motor, and transmission covers, and one of the rocker arms removed;

FIG. 2 is an enlarged fragmentary section of the over head bucket drive mechanism for clarity;

FIG. 3 is a view similar to that shown in FIG. 2 in partial section with the control valve and cam actuating mechanism therefor rotated 90;

FIG. 4 is a view similar to that shown in FIG. 3 with the drive clutches in the bucket-up low speed position;

FIG. 5 is an enlarged detailed view in partial section of the bucket power cut-elf mechanism;

FIG. 6 is an enlarged framentary sectional view substantially on line 6--6 of FIG. 5;

FIG. 7 is a fragmentary view substantially on line 77 of PEG. 6;

FIG. 8 is a diagrammatic representation of the hydraulic system of the material handling machine.

With particular reference to FIG. 1 of the drawings, there is shown a material handling apparatus generally embodying the principle of the invention. While the 3,081,890 Patented Mar. 19, 1963 material handling machine shown in the drawings and described hereinafter has endless chain type traction units, it will be evident that other forms of traction units such as wheels could be used on the machine without loss of the objects and advantages of this invention. The machine has a main frame consisting of three individual and separable sections comprising a forward section 10, a center section 12 and a rear section 14-.

The forward section 10 carries the constant mesh hydraulically actuated transmission 16 for the rear drive, endless track type traction units 18.

The center section 12 carries a single prime mover 20, centrally positioned therein, a hydraulic torque converter 22, and a pair of torque shafts, one of which is designated 24 in FIG. 2, which are positioned on either side of the prime mover 20.

The rear section 14 carries the opposed dual drives for the individually operated crawlers in the lower section and an overhead bucket actuating mechanism including a constant mesh hydraulically actuated bucket transmission, generally designated 32, positioned above the dual drives.

The forward transmission, as to be more fully described in our application Serial No. 377,125, is connected to the prime mover through a universal coupling 34 to the torque converter 22, while the rear or bucket transmission 32 is connected to the same prime mover by means of a rearwardly extending power take-off 36, belts 37 and belt sheaves 38 and 40. A rear power takeoif shaft 41 extends rearwardly from shaft 36 and rotates with sheaves 40.

On installations where the prime mover is of the Diesel or Otto cycle internal combustion type, a coolant heat exchanger 42 for the engine is positioned between the rearward extremity of the engine and the forward extension of the bucket transmission.

As more clearly shown in FIG. 3, the bucket drive mechanism and transmission is in itself a separate unit which merely bolts to the rear section of the main frame. It will also be seen that the crawler drives 28 and 3%) are each separate units which are bolted to a spacer frame 44 to form the lower portion of the rear section 14.

The main frame of the material handling machine supports an overhead bucket assembly upon parallel tracks or rails 78 secured along each side of the main frame,

The overhead bucket structure is of the overhead rocker type. The side frames 80, only one of which is shown in the drawings, of the rocker structure have curved outer surfaces for rolling engagement with the parallel rails 78, the radius of curvature of the surfaces generally increasing from the forward to the rearward ends of the curved sections.

Between the lower ends of the curved rocker arms is supported a shovel bucket 82 and each arm is also provided with a shock absorbing bumper member 84 having a spring loaded piston 86 slidably mounted therein. Each piston contacts a corresponding plate 83 secured to a rigid bumper frame 90 mounted at the rear end of the main frame when the bucket is in the dumping postion.

Flat cable chains 92, one for each rocker arm, are attached at one end to the rocker arms, as at 94, just above the bumper members 84 and the other ends are secured to their respective bucket reels 96 of the bucket transmission assembly 32. Rotation of the reels 96 raises the bucket from its forward low digging position as the rocker arms roll rearwardly along tracks 78 to an upward and rearward discharge position.

The bucket transmission 32 will be described with reference to FIGS. 2 through 8.

The bucket reels 96 are keyed to the outer ends of cross shaft which shaft is journalled for rotation in bearings 112 carried by the transmission housing 116. Also keyed to the cross shaft is a large gear wheel 118. The gear 118 is in driving relation to gear 120 on the intermediate shaft 122. The intermediate shaft 122 is journalled in bearings 124 carried by the housing 116. Also rotatable with the intermediate shaft 122 is a bevel gear 125 and a stub shaft 126; the function of the latter shaft will be described with reference to the novel power cutoff mechanism of the invention. A pinion gear 128 on shaft 130 engages the bevel gear 125. The pinion shaft is journalled in bearings 132 carried by the housing 116. Keyed to the forward end of the pinion shaft 130 is a brake disc 134 of a brake assembly generally designated 136.

A compound gear 138 having two sets of gear teeth 138' and 13$" is keyed to the pinion shaft 130 between the shaft support bearings 132. Gear teeth 133 are in constant mesh with the gear teeth of gear 140 and gear teeth 138" are in constant mesh with the gear teeth of gear 142.

Gear

140 and 142 are rotatably mounted on shaft 144, to the forward end of which is keyed the belt drum 38 hereinbefore described.

Alternate radially extending clutch discs of multiple disc clutch 146 are secured to and rotate with gear 140'. The other discs of clutch 146 are secured to the clutch housing 148, which housing is keyed to and rotates with shaft 144. Within the clutch housing is a ring shaped piston 150, spring urged out of engagement with the clutch discs. The rear portion 151 of the piston forms a presser plate for the clutch discs.

Pressure fluid is directed to the head of piston 150 through a conduit 152, a portion of which is provided by an internal passage in the shaft 144. If pressure fluid is directed into conduit 152 in the direction of the arrows in FIG. 4, the piston 150 urges the discs of clutch 146 into engagement so that gear 140 will rotate with the clutch housing 148 which is attached to shaft 144.

Alternate radially extending clutch discs of multiple disc clutch 154 are secured to and rotate with gear 142. The other discs of clutch 154 are secured to the clutch housing 156, which housing is keyed to and rotates with shaft 144. Within the clutch housing 156 is a ring shaped piston 158 spring urged out of engagement with the clutch discs. The rear portion 158 of the piston forms a presser plate for clutch discs.

Pressure fluid is directed to the head of piston 158 through conduit 160, a portion of which is provided by an internal passage in the shaft 144. If pressure fluid is directed into conduit 160 in the direction of the arrows in FIG. 3, the piston 158 urges the discs of clutch 154 into engagement so that gear 142 will rotate with the clutch housing 156 attached to shaft 144.

A third conduit 162, a portion of which is provided by an internal passage in the shaft 144, supplies lubrication for the clutches, bearings and gears of the assembly. A pressure fluid return line 364 connects the valve 164 and the transmission housing 32. The lubricating oil and the pressure fluid are drained from the lowermost portion of the transmission housing by return line 376 shown in FIG. 8 and to be more fully described hereinafter.

Conduits

152 and 160 are connected to a three spool pressure fluid control valve 164. The valve 164 is connected to a source of pressure fluid, as to be more fully described hereinafter, through conduit 166.

Spool 168 of the valve is the high-speed low-speed selector spool and is manually controlled by the machine operator through suitable control levers, a portion of which is shown at 170. Valve spool 172 is a three position spool having a bucket hold center position, as shown in FIG. 8, a bucket up position as shown in FIG. 3 and a bucket down position when the spool is in its most inwardly position. Valve spool 174 is a two position spool which is automatically actuated by the bucket power cut-off mechanism.

The power cut-off mechanism, as more clearly shown in FIGS. 3-7, comprises a cam wheel 176 adjustabiy mounted on sleeve 173 secured to shaft 184 by means of plate 1&1) and nut 122. The shaft 184 has a tapered serrated outer surface which matches internal serrations in the hub of sleeve 178. For the initial setting of the cam, the sleeve 178 is removed from the shaft 184 and relocated for the approximate position on the cooperating serrations. The final fine adjustment of thecam is made by the set screws 176' carried by sleeve 178 and which bear against the cam 176. Thus by tightening one set screw and loosening the other, cam 176 is rotated on sleeve 178 as more clearly shown in FIG. 7 of the drawings. Reference indicia may be provided on the sleeve and the cam wheel as shown at 186.

The shaft 184 is drivably connected to intermediate shaft 122 through shaft 126, worm gear 183 secured thereto, and gear keyed to the shaft 184. The ratio between the worm gear 188 and gear 191) is such that as the bucket moves from a forward digging position to an elevated dumping postion the shaft 184 makes not more than one complete revolution.

A cam arm 1*)2, having a cam engaging roller 194 at one end is pivotally mounted to the housing 116 by bolt 196.

A lever arm 198 is also pivotally mounted at one end to the housing by bolt 196. The lever arm 198 is bifurcated at its other end.

Furcation 202 is connected to one end of valve spool 174 by means of a slot and pin lost motion arrangement 204, while the other furcation 200* is pivotally mounted at the head end of a cylinder 206.

A cylinder 208, having a smaller bore than cylinder 206, is slidably mounted within the cylinder 206. A piston 210, slidably carried on piston rod 212, which extends axially through the piston, is slidably mounted in cylinder 206. A cap 207 screwed to the cylinder limits the travel of piston 210 in a direction away from the cylinder head. The inner end of pistonrod 212 is provided with a head portion 214 which is slidably mounted within the inner cylinder 208. A coil spring 216 engages the base of the inner cylinder 208 at one end and the piston 210 at the other end and urges the piston 210 and the cylinder 208 into an extended position substantially as shown in FIG. 5 of the drawings. The outer end of piston rod 212 is pivotally connected to the cam arm 122 as at 218.

In operation of the novel bucket power cut-off mechanism, the cam wheel 176 is rotated in the direction shown by the arrow as the bucket moves from a digging to a dumping position. As the bucket approaches the dumping position, cam arm 1112 is pivoted toward the cylinder 206. The initial movement of the cam arm rocks cylinder 206 and lever arm 1% downwardly which moves the valve spool 174 into a position as shown in broken lines in FIG. 5. When the spool 174 reaches its position of maximum outward travel any further movement of cam arm 192 merely compresses the spring 216 which permits the pistons 210 and 214 to slide within their respective cylinders. The pistons, cam, lever arm, and valve spool are returned by spring 216 and spring 220 at the end of spool 174 as to be more fully described hereafter.

When the shovel bucket returns from the dumping position to the digging position, cam wheel 176 rotates in a direction opposite to that shown by the arrow in FIG. 5, moving the cam arm 192 away from the spool 174. With the spool in its innermost position, as shown in the drawing, all rearward movement of the cam arm 192 is taken up by coil spring 216 as the cylinder 208 is urged away fromthe head of cylinder 206 against the force of the spring.

The position of the bucket at the time the spool 174 cuts off power to the bucket elevating transmission may be varied as hereinbefore pointed out by merely rotating the cam wheel 176 relative to the stub shaft 126.

A cycle of operation of the bucket transmission will be described in reference to FIGS. 3, 4 and 8 of the drawings.

A pump 222, driven by the prime mover 20, provides pressure fluid which is directed by conduit 166 to the valve 164. Conduit 166 is preferably provided with a pressure gauge 351 and a check valve 353. The check valve 353 prevents the flow of pressure fluid in line 166 toward the conventional torque converter 22 which as disclosed in application Serial No. 377,125 is connected to the crawler drive mechanism. The check valve 353 thus prevents pressure fluid from being robbed from the overhead bucket transmission when the bucket is raising with a load and the crawler clutches are operated to steer the machine or to reverse the direction thereof. With the spool 1'72 in the position shown in FIG. 8, the bucket will not move as the ports controlled by this spool are closed. Thus no pressure fluid can flow to

conduits

152 and 160 or to conduit 224' which connects the valve 164 and the brake actuating cylinder 226. The brake cylinder is spring urged into the brake on position and the brake is released by pressure fluid forcing the piston 227 into the brake release position against the force of spring 230 within the brake release cylinder.

When the spool 172 is moved outwardly from its neutral position to that position shown in 'FIG. 3, pressure fluid flows through conduit 224 and releases the brake 136 and a simultaneous flow of pressure fluid is directed through the

internal valve passages

228 and 229. At this point the position of valve spool 168 determines if the bucket is to be raised by means of the high speed gear 142 or the low speed gear 140.

If high speed is desired, the spool 168 is moved inwardly to the position shown in FIG. 3 and pressure fluid is directed to conduit 160 and is vented from piston 150 through conduit 152 to the valve and then through conduit 364 to the gear housing. Line 376 (FIG. 8) connects the gear housing 32 to the sump 284 from which the pump 222 sucks the liquid through conduit 386 and filter 388.

If low speed is desired, the valve spool is moved outwardly from the position shown in FIG. 3 and the flow of pressure fluid in conduits 152 and 169 is reversed.

When the bucket reaches a predetermined position, the cam actuated power cut-01f mechanism described above pulls valve spool 174 outwardly. When the spool 174 is in its outermost position, flow of pressure fluid through internal valve passage 229 is cut off stopping the flow of pressure fluid to the

piston

150 or 158 whichever the case may be, and venting the fluid in the clutch to the sump line 364, disengaging the drive to the bucket.

In order to prevent spring 220 from immediately returning the valve spool 174 to its original position the outward movement of the spool 174 opens the passage 232 so that pressure fluid is directed through duct 234 to the head of piston 236 which holds the spool 174 in the power otf position and blocks the passage 232 to the sump line 364. With the valve spool in the above described position, the bucket is free to return to the digging position by gravity.

The cam arm 192 and cam roller 194 are also held away from cam 176, so that as the bucket returns by gravity to the digging position and the cam turns in the opposite direction to the arrow shown, plunger 174 can not follow the cam movement and return pressure to the bucket clutch. The piston 236 holds the spool 174 out, permitting the bucket to fall freely to the digging position.

In order to permit valve spool 174 to return to the position shown in FIGS. 3, 4 and 8, valve spool 172 is moved to its maximum inward or bucket down position or to the center or bucket hold position. With spool 172 in either of these positions, the flow of pressure fluid to the internal valve passage 229 is cut off which prevents the flow of pressure fluid through duct 234 to the head of piston 236, thus permitting spring 220 to return valve spool 174 to its normal position. The bucket may then be raised again by moving spool 174 out to the bucket up position.

Pump 222, besides supplying pressure fluid for the operation of the crawler and bucket transmission, also supplies pressure fluid for the tractor torque converter 22, and lubricant for the crawler and bucket transmissions.

The pressure fluid from pump 222 passes through relief valve 355 which prevents excessive pressures in the bucket transmission circuit. The relief valve supplies fluid at pressure of about pounds per square inch to conduit 166 of the bucket transmission. The by-pass 357 from valve 355 supplies pressure fluid to a second relief valve 359, which supplies pressure fluid at about 70 pounds per square inch through line 361 to the torque converter 22. Fluid at any pressure in excess of 70 pounds per square inch is by-passed through line 363 to line 386 on the suction side of pump 222. A drain line 365 for the torque converter is connected to the sump line 376. The excess of pressure fluid supplied to the torque converter is filtered by filter 371 provided with a by-pass valve 372 normally set to open at a pressure of 20 pounds per square inch.

From filter 370, pressure fluid for lubrication is conducted by conduit 374 to line 162, a portion of which, as hereinbefore described, is provided by an internal passage in shaft 144 of the bucket transmission. Conduit 374 is provided with an orifice restrictor 367 to restrict the flow of lubricant to bucket transmission. An excessive flow of lubricant to the clutches of the bucket transmission has a tendency to cause a drag in the clutches resulting in a tendency to raise the bucket. With pressure at about 70 pounds per square inch, and conduit 374 having a diameter of about 4 inch a .052 inch diameter orifice was found to maintain flow at less than /2 gallon per minute which provided very satisfactory results. The lubrication rafter seeping through the bearings, clutch discs and the like is conducted by sump line 376 to the reservoir 284.

From the foregoing description of the bucket transmission, it will be seen that the bucket brake mechanism is automatically applied when the bucket control spool 172 is released by the operator. The centering spring 172' returns the spool 172 to the neutral position and in this position the pressure to the bucket brake cylinder 226 is evacuated and the springs immediately apply to the brake, holding the bucket with its load. Since the bucket brake is released by fluid pressure, it has been found that it is convenient to have a manual brake release in case a hydraulic line should break or if the prime mover should fail while the bucket is in the up position. In order to accomplish the manual release of the brake, levers 117 and 119 are suitably connected to a brake release handle not shown in the drawings.

The two speed bucket transmission provides a further multiplication of the torque advantage obtained by the combination of chain reels and rocker arm shape. EX- tremely high digging force may be obtained in low gear when the bucket is down in the digging position. As the bucket is moving over to the discharge position, the operator may change the transmission to high speed without dropping the load or slowing down the travel of the bucket. The high speed drive then gives the maximum discharge velocity to the bucket to throw the load a substantial distance. However, if desired, the bucket may be left in the low speed range and the bucket will discharge slowly for placing the load close to the rear of the machine.

While only a preferred embodiment of the present invention has been described in detail with reference to the drawings, it will be evident to those skilled in the art that various modifications may be made in the various components of the machine as defined in the appended claims.

This application is a continuation of our co-pending application Serial No. 497,754, filed March 29, 1955 which is a continuation-in-part of Serial No. 377,125, filed August 28, 1953, now Patent No. 2,843,213; and similar subject matter is disclosed and claimed in application Serial No. 361,601, filed June 15, 1953, now Patent No. 2,792,140.

We claim:

1. A material handling machine including a material handling structure, dnive means for actuating said material handling structure, said drive means including a power source, a driven shaft, fluid pressure operated clutch means between said power source and said driven shaft, a source of pressure fluid, means for selectively connecting the source of pressure fluid and the fluid pressure operated clutch, means actuated by the drive means for disconnecting the source of pressure fluid from the fluid pressure operated clutch and auxiliary pressure fluid actuated means for holding said disconnecting means in the disconnecting position after said drive means has actuated said disconnecting means.

2. A material handling machine including an overhead material handling structure, drive means for actuating said overhead material handling structure from a low forward digging position to an elevated rearward material dumping position, said drive means comprising a motor driven shaft, high and low speed gears drivably connected to said driven shaft, fluid pressure operated clutch means releasably connecting said high speed and said low speed gears with said driven shaft, a source of pressure fluid, means for selectively connecting the source of pressure fluid and the fluid pressure .operated clutches, a reel mounted for rotation on the machine, flexible draft me ans 1 connecting the reel and the overhead material handling structure, a gear train connecting the reel and said high and low speed gears, a cam drivably connected to the gear train, a cam arm engaging said cam, means connected to said cam arm for disconnecting the source of pressure fluid from the fluid pressure operated clutches said lastnamed means including a control valve having a shiftable valve spool, and pressure fluid responsivetmeans for selectively maintaining the valve spool in the power-oif position.

3. The invention as defined in claim 2 including brake means for the overhead material handling structure comprising a brake actuating cylinder, l3. piston in said cylinder, spring means normally urging the brake actuating piston into the engaged position, a fluid pressure conduit connecting the source of pressure fluid to the brake actuating cylinder, valve means in said conduit controlling the flow of pressure fluid to and from said brake actuating cylinder.

4. A material handling machine including an overhead material handling structure mounted for rolling engagement from a low forward digging position to an upward and rearward dumping position, drive means for actuating said overhead material handling structure comprising a motor driven shaft, high and low speed gears rotatably mounted on said driven shaft, fluid pressure actuated clutch means carried by said driven shaft releasably connecting said high speed and said low speed gears to said driven shaft, a reel, a cross shaft rotatably mounted on the machine and connected to the reel, flexible draft means connecting the reel and the overhead material handling structure, a gear train including at least one intermediate shaft connecting the said high and low speed gears to the cross shaft, friction brake means operatively connected to said shaft, said brake means including a brake actuating cylinder, a piston in said cylinder spring urged into the brake engaged position, a source of pressure fluid, a pressure fluid control system comprising first, second and third pressure fluid control valves, conduit means connecting the source of pressure fluid to said first control valve, conduit means connecting said first control valve with the brake actuating cylinder and the second control valve, conduit means connecting said second control valve with said third control valve, and conduit means connecting said third control valve with said clutch means carried by said driven shaft, and means connecting said drive means with said second control valve for stopping the flow of pressure fluid to said third control valve.

5. The invention as defined in claim 4 wherein said means connecting said drive means to said second control valve comprises a cam drivably connected to said intermediate shaft, a cam arm engaging said cam, and means connected to said cam arm for actuating said second control valve.

6. A material handling machine including an overhead material handling structure, drive means for actuating said material handling structure, said drive means comprising a motor, a driven shaft, fluid pressure operated clutch means between said driven shaft and said motor, a source of pressure fluid, valve means for selectively connecting the source of pressure fluid and the fluid pressure operated clutch, a reel mounted for rotation on the machine, flexible draft means connecting the reel and the overhead material handling structure, means drivably connecting said reel and said driven shaft, fluid pressure actuated brake means for said overhead material handling structure, conduit means connecting said brakemeans and said valve means whereby when said fluid pressure operated clutch is engaged the brake is disengaged and when said clutch is disengaged said brake is engaged and pressure fluid flow control means interposed between said valve means and saidclutch means for disengaging said clutch means while said brake is disengaged, means actuated by said driven shaft for moving the pressure fluid flow control means to disengage the clutch means, and auxiliary pressure fluid responsive means for holding said pressure fluid flow control means in the clutch disengaged position.

7. The invention defined in claim 6 wherein said flow control means is actuated when the material handling structure is in the material discharge position.

References Cited in the file of this patent UNITED STATES PATENTS 2,108,959 Brown Feb. 22, 1938 2,652,855 Wright Sept. 22, 1953 2,729,348 Hackett et al. Jan. 3, 1956 2,752,053 Schwartz June 26, 1956

Claims

1. A MATERIAL HANDLING MACHINE INCLUDING A MATERIAL HANDLING STRUCTURE, DRIVE MEANS FOR ACTUATING SAID MATERIAL HANDLING STRUCTURE, SAID DRIVE MEANS INCLUDING A POWER SOURCE, A DRIVEN SHAFT, FLUID PRESSURE OPERATED CLUTCH MEANS BETWEEN SAID POWER SOURCE AND SAID DRIVEN SHAFT, A SOURCE OF PRESSURE FLUID, MEANS FOR SELECTIVELY CONNECTING THE SOURCE OF PRESSURE FLUID AND THE FLUID PRESSURE OPERATED CLUTCH, MEANS ACTUATED BY THE DRIVE MEANS FOR DISCONNECTING THE SOURCE OF PRESSURE FLUID FROM THE FLUID PRESSURE OPERATED CLUTCH AND AUXILIARY PRESSURE FLUID ACTUATED MEANS FOR HOLDING SAID DISCONNECTING MEANS IN THE DISCONNECTING POSITION AFTER SAID DRIVE MEANS HAS ACTUATED SAID DISCONNECTING MEANS.