US2974812A - Load-handling apparatus for building blocks and the like - Google Patents

Description

March 1961 c. w. BOPP 2,974,812

LOAD-HANDLING APPARATUS FOR BUILDING BLOCKS AND THE LIKE Filed Aug. 21, 1958 3 Sheets-Sheet 1 6 I 0 U A 2 INVENTOR.

C. W. BOPP ATTORNEY March 14, 1961 c. w. BOPP 2,974,812

LOAD-HANDLING APPARATUS FOR BUILDING BLOCKS AND THE LIKE Filed Aug. 21. 1958 3 Sheets-Sheet 2 64 INVENTOR. C. W. BOPP BY l 4- q ATTORNEY c. w. BOPP 2,974,812

3 Sheets-Sheet 3 HHIIII INVENTOR. C. W. BOPP I36 Isa v Ill: lllllllll I36 I50 I ATTORNEY March 14, 1961 LOAD-HANDLING APPARATUS FOR BUILDING BLOCKS AND THE LIKE Filed Aug. 21, 1958 FIG.

United States Patent LOAD-HANDLING APPARATUS FOR BUILDIYG BLOCKS AND THE LIKE Cecil W. Bopp, Waterloo, Iowa, assignor to Bopp Mfg Inc., Waterloo, Iowa, a corporation of Iowa Filed Aug. 21, 19 58, Ser. No. 756,433

14 Claims. (Cl. 214"6) This invention relates to load-handling apparatus and more particularly to the handling, palleting and preparation for transport of building blocks of conventional type made of concrete, cinder or equivalent aggregates and having apertures therethrough.

As is known to those versed in the art, typical building blocks for foundations, Walls, etc. are furnished in various sizes and types, the twoor three-hole 8 x 8" x 16" being a popular style and size wherein the two or three holes or apertures therethrough are commonly provided for purposes of insulation, material savings and so forth. It has become common in the industry to handle these blocks in what are known as cubes, usually consisting of, say, five or six layers of blocks arranged to form a cube six blocks deep, three blocks wide and five or six blocks high; although, these dimensions may be varied, being given here merely by way of example.

It is also common practice to handle these cubes either by placing each cube on a plate or pallet or by utilizing the lowermost layer as a pallet so that the tines on a fork lift truck, for example, may be received in the apertures of the lowermost layer. The latter system is by far the more desirable, for obvious reasons, but heretofore construction of the cubes in such manner as to make that method feasible has been difficult, expensive and time consuming. The greatest obstacle to the successful practice of that system is that the blocks are conventionally manufactured by casting, molding, etc. in such manner and position that they are discharged with their apertures upright and it is therefore necessary to turn the blocks '90 to dispose their apertures horizontally if they are to serve as elements of the pallet. The usual block grab or similar equipment used to remove the blocks from the manufacturing equipment is not capable of turning the blocks as desired and hence'turning has heretofore been accomplished manually, at considerable cost in time and effort.

According to the present invention an improved apparatus and system for handling, cubing, and palleting blocks and the like is afforded, featuring the provision of means whereby a plurality of'upright layers of blocks are received from the block grab and are then turned bodily to a horizontal posit-ion to achieve alike plurality of stacked pallets, each having its' block aperture horizontal, since the block-receiving means turns the blocks through approximately 90. Thereafter additional blocks are stacked on the pallet layers and a cube may be built in usual fashion on the uppermost pallet, irrespective of the positions of the'apertures in the added blocks. This cube, with the upper pallet layer as a base, may he removed, as by' a'fork lift truck, from the remaining pallet layers and the'process'repeated by adding blocks to each succeeding pallet layer as long as stacked pallet layers remain, after which the apparatus is'operatedas before to form and'accumulate other'palletlayers and so 'on.

2,974,812 Patented Niel, 14, 1961 ice regulating means for the control means, means for automatically returning the element to loading position after it is unloaded, latch means for retaining the down or unloading position of the element, novel fluid chamber and reservoir means and valve means therefor, coordinated control means for the valve and latch means, movable or foldable parts on the palleting element facilitat ing cubing and unloading, a simple and inexpensive de-- sign and construction, and other features and advantages: as will appear from the ensuing disclosure of a pre-- ferred embodiment of the invention as illustrated in the accompanying sheets of drawings, the several figures of which are described below.

Figure l is a side elevation of the a paratus in its loading position.

Figure 2 is a side elevation of the apparatus in its unloading or palleting position.

Figure 3 is a fragmentaiy view showing the folded position of part of the rack or 'palleting element.

Figure 4 is a plan of the apparatus in its Figure 2 position.

Figure '5 is a front view of the apparatus in its Figure 2 position.

Figure 6 is a slightly enlarged view as seen on the line 6-6 of Figure 5.

Figure 7 is an enlarged view of the fluid reservoir, partly in section as seen along the line 7'7 of Figure 4.

Figure 8 is a section on the line 88 of Figure 7.

Figure 9 is a section, enlarged, on the line 9-9 of Figure 4.

Figure '10 is a section on the line EAL-1t? of Figure 8.

Figure 11 is a side view on a reduced scale, showing receipt of the generally upright layers of blocks.

Figure 12 is asimilar view but shows the apparatus in its down position so that the layers become pallets for the building of as many cubes as there are layers.

The apparatus comprises a base or support means 20 having front and rear ends 22 and 24 respectively and a load-receiving or block-palleting element in the form of an L-shaped frame or rack 25 including a first or long leg 28 and a-second or short leg 30. The base is suitably constructed of rigid laterally spaced fore-andaft members 32 and cross members 34, rigidly secured together to form a generally rectangular structure adapted to rest on the ground or door, and this structure is provided at its front end with laterally spaced apart short uprights 36 respectively having transversely coaxial trunnions 38 which establish a transverse Pivot for the rockable mounting of the rack 26at'the lower front corner thereof or generally at the junction of the rack legs 26 and 28.

The short leg'30 of the'rack is of two-piece construction, as will be described below, and each piece is relatively wide to conform to the overall 'width of the rack, which, like the base, is constructed of suitable fore-andaft members '40 and cross members 42 rigidly united to afford the necessary strength and area for supporting the load, here represented in part by a plurality of layers A, B, C of hollow or apertured building blocks of the character already'referred to. "When the rack 26 is in its up or loading position,Figures 1 and 11, the leg 28 is layers.

facturing apparatus (not shown since it is conventional) in the generally upright positions shown, and therefore the apertures a, b, c of the blocks will also be upright. This result is due to the manner in which the blocks are cast or molded and also due in part to limitations on the operation of the means, such as a block grab (likewise not shown, since it is conventional) used to remove the blocks from the manufacturing machine. As will be seen, handling of the blocks in their upright positions does not lend itself to the palleting operation unless the blocks are first turned to horizontal positions. This task, heretofore performed manually and at considerable cost in time and labor, is achieved simply and rapidly by the present apparatus by merely rocking the loaded rack 26 rearwardly and downwardly about the base pivot 38 to the palleting or unloading position of Figures 2 and 12. Hence the layers A, B, C now are horizontal and are used as successive pallet layers for the building of as many block cubes as there are pallet layers, here three. Figure 12 shows four added layers D, E, F, G of blocks resting on the uppermost pallet layer A to form a cube H. These added blocks have been transferred in their original upright positions and therefore their apertures d, e, f, g are upright, which is immaterial in view of the fact that the cube H thus established is based on the pallet layer A in which the horizontal and alined apertures of the pallet layer blocks are adapted to receive the load-engaging means of cube-handling equipment, represented here as the fork or tine means T of a conventional fork lift truck. The full-line position of the fork T in Figure 12 shows how the cubeH, including the pallet layer A, can be removed from the two remaining pallet layers B and C. Next, another cube is built on the pallet layer B and removed by the means T (next lower dotted line position) in the same manner as the cube H, and the process is repeated by building another cube on the layer C and removing same by the means T (lowest dotted line position), after which the now empty rack is returned to its up position for another load of pallet It will be recognized, of course, that the size of the apparatus may be varied to acommodate fewer or more pallet layers than shown and that smaller or larger cubes of the same or larger or smaller blocks can be erected successively on the pallet layers. The example illustrated here is based on highly successful current experience with block handling by the disclosed apparatus and method.

As previously indicated, the rack leg is of two-piece construction, including a fixed part 44 rigid on the rack and a movable part 46 pivoted to the fixed part 44 at 48, thus making the leg 30 a foldable structure. In the loading position of the rack (Figures 1 and 11) the two parts 44-46 are extended as a rigid support for the blocks, and they are retained in this position by releasabletoggle means including a lever 50 and link 52. The lever is'fulcrumed at 54 on a rigid forward arm 56 on the rack and the link is connected atone end at 58 to the lever and at its other end at'60 to the leg part 46 in spaced relation to the pivot 48. A tension spring 62 is connected to the toggle at the link-to-lever pivot 58 and to the fixed leg part 44 and draws the toggle upwardly (Figure 1) so that the pivot 53 is over-center as respects the points 54 and 6t) and the joint between the link 52 and lever 50 abuts the front edge of the fixed leg part'44, thus locking the toggle against collapse and therefore rigidity.- ing themovable leg part 46. e

The advantage of the foldable leg construction for the leg 30 is that the upper or movable part 46 may be folded downwardly and out of the way (Figure 3) so as to shorten the height of the legin the unloading or down position of the rack 26, thus making it unnecessaryto lift blocks as high as would berequired were the leg of perinenent height. This 'becomes importantwhen building cubm on the lower pallet layers B and'C. Movement of the leg part 46'to its Figure 3 position is accom plished manually following automatic release of the toggle 50-52 responsive to attainment by the loaded rack of its palleting or down position. This action is best seen in Figure 2 and follows from the fact that a tail 64 on the lever 50 engages a stop 66 on the base 20, resulting in breaking the toggle so that the point 58 moves overcenter forwardly as respects the points 54 and 60. The spring 62 tends to retain the positions of the parts but since the toggle is released as already described, the user may readily swing the leg part 46 forwardly and downwardly to the Figure 3 position. When the rack is ready for return to its up position, the leg part 46 is manually returned to its Figure 2 position and as the rack swingsupwardly and forwardly the tail 64 on the lever 50 is freed of the stop 66 and the spring 62 re-locks the toggle 5%52. It will be clear that the toggle and control means is duplicated at both sides of the front of the apparatus (Figures 4 and 5). p

The mounting of the rack 26 on the base 20 via the pivot 38 is effected by short rigid arms 68 fixed to the lower front corner of the rack and crosseconnected by a vertical plate 70. These arms extend downwardly and forwardly and each has a transverse pivot pin 72 connected to the front end of a piston rod 74 for a piston 76 carried in a cylinder 78. Each piston-cylinder unit extends fore-and-aft and lies closely alongside the proximate side member 32 of the base 20 and is supported at its rear end by a long bolt 80 which is ar-ticulately anchored at 82 to the rear cross member 34 of the base. The front end of each bolt is threaded into a blind tapped bore 84 in the rear end of its cylinder and the interior of the cylinder has a shoulder which forms a stop against which the rear of the piston 76 abuts. A jam nut 86 secures the position of the bolt relative. to .the cylinder. The purpose of the adjustment just described at 84 is to regulate the range of forward and upward swinging of the rack to such up or loading position, as depicted in Figures 1 and 11, that the rack leg 28 inclines slightly rearwardly to achieve a position in whichthe loaded rack just overbalances rearwardly against biasing means in the form of a tension spring 88 anchored to the base 20 at 90 and connected to the front lower part of the rack 26 by a chain 92 and arcuate segment 94 rigidly welded to the .rack and reenformed by a pair of angles 96 (Figures 5 and 6).

The spring 88 tends to return the empty rack 26 to its loading position by the energy stored therein when the rack descends to its palleting position, in which position it is releasably retained by latch means comprising a latch 98 pivoted at 100 to the base 20. and a latchengaging pin 102 on the rack. The top of the latch is so shaped that latch means automatically latches when the rack reaches its down or palleting position, the latch being biased by, a tension spring 104.anchored at 106 to the base and connected to an arm 108 (Figure 5) rigid on a transverse rockshaft or operating member 110 which is journaled on the base in any suitable fashion. This 'rockshaft is equipped at each end with control members or pedals 112 and intermediate its ends rigidly carries an arm 114 linked at 116 to the latch 98. Depression of either pedal 112 rocks the rockshaft 110 counterclockwise and releases the latch 98. When pressure is released from the pedal, the spring 104 returns the latch 98 toposition to again engage the latch pin 102 on the rack when the rack descends to its down position.

The pedal and rockshaft asan operating mearn also controls or regulates the fluid-control effect of the cylinders 78 on the lowering of the rack, since these cylinders operate as part of regulating means acting to retard descent of the rack so that the operation of the apparatus occurs speedily but without undue shock and noise. For this purpose, the cylinders 78 are associated with a reservoir 118, here centrally disposed between the cylinders (Figures 4 and 5) and mounted at its rear end as by a long bolt 120 and mounted at its front by a strap 122 (Figure 7) loose on the rockshaft 110. The rear end of the reservoir may be mounted in any other manner and the bolt 120 as a mounting expedient may be dispensed with if desired, the strap 122 being relied upon to locate and confine the reservoir as it rests on the ground or floor. The reservoir afiords one fluid-containing chamber and each cylinder affords another, and the three members 118 and 78-78 are interconnected by front and rear fluid lines 124 and 126 for the interchange of fluid under control of valve means denoted as a whole by the numeral 128 (Figures 7-10). Thus, each cylinder 78 and its piston 76 comprise relatively movable members, one of which (the cylinder) includes a chamber, and the other of which (the piston) acts on the fluid in the chamber. The connections of the rear hose lines 126 between the rear ends of the cylinders and the rear end of the reservoir is a matter of expedience in eliminating air and accommodating leakage in the system and these units at their rear ends have free fluid interchange without the use of valve means.

The valve means 128 comprises a valve housing 130 rigidly aflixed to the front of the reservoir 118, as by a forward eXtension of the bolt 126 (Figure This housing has opposite tapped bores 132 for receiving the front hose lines 124 and these bores lie at opposite ends of a cross passage 134. A central valve bore 136, normal to and below the passage 134, is connected by a short vertical passage 138 to the passage 134 and is further connected by a transverse passage 141 and a rearward passage 142 to the interior of the reservoir. The lateral passage 140 is enlarged and tapped at 144 to carry an adjustable needle valve 146 for regulating the rate of fluid flow past a seat 148 in the passage 140 and thus controls the rate of fluid flow through the passage means 134-138-136-148-142 when this passage means is opened by a normally closed valve plunger 150 which controls communication between the passages 138 and 140 via the valve bore 136.

The valve plunger 150 has a coaxial rigid forward extension or stem 152. which passes loosely through an apertured valve control arm 154 rigid on the rockshaft 110 and bifurcated (Figure 5) to straddle the mounting strap 122. The stem is headed at 156 and carries front and rear washers 153 respectively ahead of and behind the arm 154, which is shaped as shown in Figure 7 to afford smooth operation. A coiled compression spring 168 encircles the stem and acts between the plunger 150 and the rear washer 158 to aiiord a yielding force-transmitting connection between the arm and the plunger in the direction (rearward) of vaive plunger closing. The head 156 and front washer 158 afford a positive oneway force-transmitting connection between the control arm 154 and plunger 150 in the direction (forward) of valve plunger opening. The plunger 150, once opened by depressing the pedal 112, may remain open even though the pedal is released and arm 154 is consequently rocked clockwise or in the direction of valve closing by the rockshaft spring 104, previously described, since the spring 168 may be compressed by the arm 154 While the plunger 15% is still forwardly or in open position. This will become clearer below.

When the rack 26 is in its loading position, it tends to remain there, at least while empty, because of the bias in the rack control spring 88, and the position of the rack when loaded and lowered is determined by the adjustment of the cylinder at 84, plus the latch. As already suggested, these bolts have been adjusted to secure the described position, which is one inwhich the loaded rack just overbalances rearwardly when raised. However, at this time the valve plunger 158 is closed and fluid trapped in the cylinders 78 ahead of the pistons 76 cannot flow to the reservoir via 134-138-136140- 142, since the plunger 150 blocks 138 from 136 (Figme, 10).

Nor can fluid escape from the fronts of the cylinders via by-pass means, since this by-pa'ss means is effective to transmit fluid only from the reservoir to the cylinders. For this purpose, the valve housing has a second reservoir passage 162, a lateral passage 164 and a ver tical passage 166 leading to the cross or hose line passage 134 (Figure 9), but the passage 166 is closed to cylinder to-reservoir flow by a spring-loaded ball check valve 168. This check valve can, however, open in the direction of reservoir-to-cylinder flow, which will occur when the rack rises.

The loaded rack is retained in its up position until the rockshaft 110 is rocked by depression of one of the pedals 112, which opens the plunger bore 136 as the arm 154 retracts the plunger 150. Fluid flow from the front ends of the cylinders 78 as the pistons 76 move forwardly is via 124, 134, 138, 136, 148 and 142 and past the needle valve 146, which is set to regulate the rate of flow and hence the rate of descent of the loaded rack.

It is at this point that the significance of the yielding force-transmitting connection 152-160 between the arm 154 and plunger 158 will be appreciated, since it eliminates the need for keeping the pedal 112 depressed while the rack descends. Since the pedal can thus be released, the latch 98, which is rocked in its release direction by rocking of the rockshaft 110 to open the valve bore 136, can be returned to latching condition by the return spring 104 without effect on the valve means. When the plunger is retracted forwardly to its open position, its rear end moves ahead of the passage 138 and fluid flowing past the plunger end acts to keep the plunger open against the spring even though the pedal 112 is'released and the return spring 104 rocks the rockshaft 118 clockwise.

.When the rack reaches its down position, the conditioned latch 98 secures it there and since fluid flowthrough the valve now ceases, the spring 160 closes the valve by shifting the plunger rearwardly to closed position. As the latch 98 is nudged forwardly by the latch pin when the rack attains its down position, the link 116 will transmit force to the rockshaft 110 but this has no adverse effect on the valve plunger.

When the rack is empty in its down position, the rack return spring 88 is fully loaded or tensioned, but the latch 98 retains the down position of the rack. Depression of either pedal rocks the rockshaft 110 to release the latch 98 and the rack automatically moves to its up position. As it does so, the pistons 76 move rearwardly in the cylinders 78 and draw fluid from the reservoir 118 via 124-134-166 (past the check valve 168), 164-162 and, although some fluid may return past the presently opened valve bore 136, this amount is of little import, because as soon as the latch 98 is released to enable upward movement of the rack, the pedal is released and the return spring 104 acts to turn the rockshaft clockwise and the arm 154 thus acts through the spring 160 to move the valve plunger 150 rearwardly to its closed position, the fluid flow past the plunger at 138 being insuflicient to achieve the results that occur when the rack descends.

As will be clear from the foregoing, without further elaboration, the apparatus disclosed is of novel construcmay be achieved without departure from the spirit and scope of the invention.

What is claimed is:

1. Apparatus for use in the palleting of aperture d building blocks and the like, comprising: a base having. front and rear ends and including a transverse horizontal pivot at said front end; a block-receiving rack of L-shape having first and second angularly related legs and mounted on said pivot generally at the junction of said legs for rocking downwardly from a block-receiving loading position in which the first leg extends generally upright and the second leg extends forwardly to an unloading position in which the first leg extends generally horizontally rearwardly and the second leg extends upwardly whereby the blocks are turned approximately 90; a pair of fore-andaft cylinder and piston units disposed generally horizontally and laterally spaced apart and connected between the base and rack; a fluid reservoir disposed centrally between said units; fluid lines connecting the reservoir to thetunits for transfer of fluid between said units and reservoir during rocking of the rack; valve means closing the fluid lines off from the reservoir in the loading position of therrack so as to retain said loaded position by trapping fluid in the units; operating means for opening the valve means to enable fluid flow from the units to the reservoir during descent of the rack; means for regulating Said fluid flow to the reservoir; biasing means connected between the rack and base and loaded to store energy during descent of the rack for returning the rack to its loaded position; latch means for releasably retaining the rack in its unloading position; means for releasing the latch means to effectuate the biasing means when the'rack is unloaded; and fluid by-pass means between the reservoir and the units and bypassing the valve means during return of the rack to its loading position to enable the units to draw fluid from the reservoir, said by-pass means including check valve means preventing fluid flow from the units to the reservoir. 7

2. The invention defined in claim 1, in which: the rack is constructed and arranged so that in its loading position the first leg extends rearwardly as well as upwardly whereby the rack when loaded is overbalanced toward itsunloading position but is retained by the closed valve.

'3. The invention defined in claim 1, in which: the second leg of the rack includes a movable part movable relative to the rack to enable shortening of the height of said second leg in the unloading position of the rack.

4. The invention defined in claim 1, including: a rockshaft carried by and extending transversely of the base; and the means for operating the valve means and the means for releasing the latch means are operatively connected to said rockshaft. r

5. Apparatus for use in the palleting of apertured building blocks and the like, comprising: a base having a pivot on a horizontal axis; an L-shaped block-receiving rack having first and second angularly related legs and mounted on said pivot generally at the junction of said legs for rocking of said rack downwardly from a'blockreceiving loading position in which the first. leg extends generally upwardly and the second leg extends normal to said first leg to an unloading position in which said first leg is generally horizontal and said second leg extends upwardly whereby rack-received blocks are turned approximately 90; means for regulating descent of the loaded'rack to its unloading position, including a pair of a efiect regulated descent of the rack to its unloadingsposi- 7 tion; biasing means connected between the base and rack and loaded by descent of the rack to store energytfor returning the rack to its loading position;-latch means releasably retaining the rack in its; unloading position; means for releasing the latch to elfectuat'e the loaded 7 biasing means; and one-way fluid-conducting means connectedto the chamber and by-passing the valve means to enable reverse movement of fluid in the chamber during return of the rack to its loading position.

6. The invention defined in claim 5, including: a common control element for the valve means and the latch means; means interconnecting said element and the valve means and latch means; means biasing the control element to a position incurring latching of the latch means and closing of the valve means; said valve means having a pressure-receivable area subject to fluid flow through the passage upon opening of said valve means to retain the valve means open as long as fluid flows through said passage irrespective of the position 'of the control element; and said means interconnecting the control element and valve means including a yielding means enabling return of the control element to its aforesaid position while the valve means remains open as aforesaid because of fluid flow through said passage.

7. Apparatus for use in the palleting of apertured building blocks and the like, comprising: a base having a pivot on a horizontal axis; an L-shaped block-receiving rack having first and second angularly related legs and mounted on said pivot generally at the junction of said legs for rocking of said rack downwardly from a blockreceiving loading position in which the first leg extends generally upwardly and the second leg extends normal to said firstleg to an unloading position in which said first leg is generally horizontal and said second leg extends upwardly whereby blocks received by the rack in the loading position thereof have their apertures disposed generally vertically and are turned during descent of the rack to its unloading position so that said apertures are horizontal; and said second leg including a first part rigid with the rack and projecting generally normal thereto and a second part normally serving as an extension of said first part but movable relative to said first part to a retracted position to enable shortening of the height of said second leg in the unloading position of said rack.

8. Apparatus for use in the palleting of apertured building blocks and the like, comprising: a base having a pivot on a horizontal axis; an L-shaped block-receiving rack having first and second angularly related legs and mountedton said pivot for rocking of said rack downwardly from a block-receiving loading position in which the first leg extends generally upwardly and the second leg extends normal to said first leg to an unloading position in which said first leg is generally horizontal and said second leg extends upwardly whereby blocks received by the rack in the loading position thereof have their apertures disposed generally vertically and are turned during descent of the rack to its unloading position so that said apertures are horizontal; and said second leg including a first part rigid with the rack and projecting generally normal thereto and a second part normally serving as an extension of said first part but movable relative to said first part to a retracted position to enable shortening of the height of said second leg in the unloading position of said rack. 7

9. The method of palleting apertured building blocks and the like in which such blocks are conventionally manufactured with their aperturesrupright, comprising the steps of receiving simultaneously a plurality of layers of such blocks with their apertures upright; turning the plurality of layers approximately to form as many horizontal pallets as there are layers and wherein. all apertures are horizontal and the apertures in each pallet run-inthe same direction; adding blocks to the uppermost pallet; removing said uppermost pallet and added blocks; adding other blocks to the next uppermost pallet; removing said next uppermost pallet and other blocks; and repeating the addition of blocks and removal of pallets as often as there are pallets.

10.-Apparatus of the'class described, comprising: a base; a load-receiving 'element mounted on the base for movement downwardly under load from a loading posi-' tion to an unloading position and; return; a pair of relatively movable members connected respectively to the base and element, one member comprising a fluid chamher and the other comprising a piston in said chamber, said chamber having a fluid passage and said piston being movable upon descent of the element to exhaust fluid from the chamber via said passage; a valve closing said passage in the loading position of said element; manually controlled operating means for opening said valve to enable fluid flow through said passage; means for returning the element to its loading position; one-way fluid conducting means by-passing the valve to enable the chamber to take in fluid during return of the element to its loading position irrespective of the open or closed condition of the valve; fluid-receivable means on the valve operative to automatically retain the open position of the valve as long as fluid flows through the passage means; and biasing means in said operating means and operating on the valve to close said valve when fluid flow through said passage means ceases.

11. Apparatus of the class described, comprising: a base; a load-receiving element mounted on the base for movement downwardly from a loading position to an unloading position and return; a pair of relatively movable members connected respectively to the base and element, one member comprising a fluid chamber and the other comprising a piston in said chamber, said chamber having a fluid passage and said piston being movable upon descent of the element to exhaust fluid from the chamber via said passage; a valve closing said passage in the loading position of said element; a manually controlled operating member movable between first and second positions and biased to its first position; a one-way force-transmitting connection between the operating member and valve for opening the valve when said operating member is moved to its second position and enabling return of said operating member to its first position independently of said valve; means responsive to fluid flow through the passage for retaining the open position of the once-opened valve irrespective of return of the operating member to its first position; and yielding means for closing the valve when fluid flow through said passage ceases.

12. The invention defined in claim 11, including: means biasing the element toward its loading position when unloaded; latch means for retaining the element in its unloading position against the action of said biasing means; and means operatively connecting said latch means to the operating member.

13. Apparatus for use in the palleting of apertured building blocks and the like, comprising: a base having a pivot on a horizontal axis; an L-shaped block-receiving rack having first and second angularly related legs and mounted on said pivot generally at the junction of said legs for rocking of said rack downwardly from a blockreceiving loading position in which the first leg extends generally upwardly and the second leg extends normal to said first leg to an unloading position in which said first leg is generally horizontal and said second leg extends upwardly wherebyblocks received by the rack in the loading position thereof havetheir apertures disposed generally vertically and are turned during descent of the rack to its loading position so that said apertures are horizontal; said second leg including a part pivoted to the rack for swinging downwardly relative to the rack between up and down positions; toggle means between said part and the rack for retaining the up position of said part in the loading position of the rack; and means engaging the toggle means and operative responsive to attainment by the rack of substantially its unloading position for changing the toggle means so that said part may move to its down position.

14. Apparatus for use in the palleting of apertured building blocks and the like, comprising: a base having a pivot on a horizontal axis; an L-shaped block-receiving rack having first and second angularly related legs and mounted on said pivot generally at the junction of said legs for rocking of said rack downwardly from a blockreceiving loading position in which the first leg extends generally upwardly and the second leg extends normal to said first leg to an unloading position in which said first leg is generally horizontal and said second leg extends upwardly whereby blocks received by the rack in the loading position thereof have their apertures disposed generally vertically and are turned during descent of the rack to its unloading position so that said apertures are horizontal; said second leg including a part pivoted to the rack for swinging downwardly relative to the rack between up and down positions; release means connected between the rack and said part for retaining the up position of the part in the loading position of the rack; and means engaging the release means and operative responsive to attainrnent by the rack of substantially its unloading position for operating the release means so that said part may move to its down position.

References Cited in the file of this patent Thomas Sept. 3, 1957

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