US 3822803 A
An attachment for a lifting vehicle, comprising a rear frame having means for attachment to a vehicle, a mid-frame rotatably mounted on the rear frame for rotation relative thereto about an axis substantially perpendicular to the plane of the rear frame, a front plate hinged at one side thereof to the mid-frame, means for opening and closing the hinge to pivot the front plate away from and towards the mid-frame, means for moving the hinge longitudinally of the mid-frame from side to side thereof and mounting means at both opposite longitudinal edges of the front plate to which material handling members may be attached.
Claims available in
Description (OCR text may contain errors)
States Patent Marsden 214/730 Thompson July 9, 1974 MATERIAL HANDLlNG EQUIPMENT Primary Examiner-R0bert J. Spar  lnventor' g iggg Davls Thompson F Attorney, Agent, or Firm-Stevens, Davis, Miller &
Mosher  Assignee: R. E. Barker & C0., Yorkshire,
England 57 ABSTRACT  Flled: 1973 An attachment for a lifting vehicle, comprising a rear  Appl. No: 343,941 frame having means for attachment to a vehicle, a
. mid-frame rotatably mounted on the rear frame for rotation relative thereto about an axis substantially 2% g g g/zj perpendicular to the plane of the rear frame, a front 6 731 plate hinged at one sidelthereof to the mid-frame, 1 0 earc means for opening and closing the hinge to pivot the 56 R f d front plate away from and towards the mid-frame, 1 e erences means for moving the hinge longitudinally of the mid- UNITED STATES PATENTS frame from side to side thereof and mounting means 2,780,377 2/1957 Glenn, Jr. et al. 214/620 X at both opposite longitudinal edges of the front plate ,096,896 7/1963 Norton et al. 214/620 X to which material handling members may be attached. 3,106,305 10/1963 G h 214/620 X 3,738,512 6/1973 8 mg 10 Claims, 9 Drawing Figures PATENTEDJUL 1914 SHEET 1 [IF 8 mww QNN mmw 2N mww @NN PATENTEUJUL 3,822,803
SHEET 2 BF 8 I PAT ENTEU JUL 91914 snm 3 0r 8' I PATENTED JUL 91914 SHEEI 5 OF 8 PATENTED JUL 91974 I 3.822 8 O3 SHEEI 7 [IF 8 188 f \El PATENTED JUL 91974 sum 8 OF 8 MATERIAL HANDLING EQUIPMENT This invention relates to material handling equipment, and more particularly to an attachment for fork lift trucks and other lifting vehicles and to vehicles equipped with such an attachment.
The load carrier of a fork lift truck is generally di rectly mounted in the carriage plate which is slidably mounted for vertical movement up and down the mast. On such trucks there is no provision for pivoting the load carrier out of its straight-ahead position to project toward either side of the truck. Such a facility is useful for handling loads to each side of a narrow aisle along which-the truck can move only forwards and backwards.
A number of attempts have been made to provide fork lifttrucks or attachments therefor which will provide this facility. These have generally relied upon frames placed one in front of another and pivotally connected one to another so that the more forward frames may be pivoted on the more rearward ones from a position pointing straight ahead of the truck to positions pointing to either side of the truck. The present invention proposes an alternative construction for the attachment which has certain advantages over the known attachments.
According to the present invention an attachment for a lifting vehicle, particularly a fork lift truck, comprises a rear frame having means for attachment to a vehicle, a mid-frame rotatably mounted on the rear frame for rotation relative thereto about an axis substantially perpendicular to the plane of the rear frame, a front plate hinged at one side thereof to the mid-frame, means for opening and closing the hinge to pivot the front plate away from and towards the mid-frame, means for moving the hinge longitudinally of the mid-frame from side to side thereof and mounting means at both opposite longitudinal edges of the front plate to which material handling members may be attached.
The invention also includes a vehicle having an attachment as aforesaid fitted thereto. The vehicle may preferably be a fork lift truck, in which case the attachment meanson the rear frame are means for securing that frame to the standard carriage plate of the fork lift truck. The front plate'may have mounting means for any contemplated variety of forks, arms and other material handling members.
In normal use, assuming that the attachment is fitted to the standard carriage plate of a fork lift truck, the front plate is folded back to lie parallel with and ahead of the mid-frame, with the hinge positioned at one edge of the mid-frame and the mid-frame and front plate lying substantially within the same confines when viewed forwardly from the truck. The front plate has first and second longitudinal edges respectively uppermost and lowermost and extending substantially horizontally, and material handling members are fixed to the mounting means associated with the second (lowermost) edge. The truck can thus operate as a conventional fork lift truck.
Assume now that, looking forward fromthe driving position, the hinge is at the right hand side of the midframe and it is desired to side stack to the right of the truck. To do this the hinge is opened to move the front plate to take up a position projecting forwardly from, and at right angles to, the mid-frame. The load handling members then project to the right of the truck, and by traversing the hinge across the mid-frame from its'limit right hand to its limit left hand position the load handling members can be moved between positions projecting beyond the sides of the mid-frame or lying within the limits of the mid-frame.
To side stack to the left of truck, from the normal operating position described, the mid-frame is first rotated through 180 on the rear frame to invert the midframe and front plate and position the hinge at the left hand side of the mid-frame. The load handling members on the second (now the uppermost), longitudinal edge of the front plate are removed or rendered inoperative, and load handling members on the first (now the lowermost) longitudinal edge of the front plate are fit ted or rendered operativeaopening of the hinge will thus pivot the load handling members to the left of the truck, and traversing of the hinge on the mid-frame may again be effected.
Preferably the attachment is such that pivotal movement of the front plate away from the mid-frame occurs I simultaneously with longitudinal movement of the hinge across the mid-frame. Thus, the load handling members can be turned from a front facing to a side facing position within the confines of the length of the attachment. Conversion to side-stacking can thus be effected in narrow aisles.
When a load is being handled in a side stacking position it is desirable for the load to be tilted towards the attachment to imp'rovestability, and it will be seen that a small rotational movement of the mid-frame on the rear frame can readily achieve this effect.
Conveniently the mounting means for the load handling members include hinges to which the load handling means are secured so that when the hinges are on the uppermost edge of the front plate the load handling members hang down substantially parallel to and in contact with the front plate, and when the hinges are on the lowermost edge of the front plate the load han dling members project forwardly from the front plate and substantially normal thereto. Thus, as the attachment is rotated from a right side stacking form to a left side stacking form or vice versa one set of load handling members will fall by gravity about their hinges to an out of use position, and the other set will fall by gravity about their hinges to an in use position.
In order that the invention may be fully understood a specific embodiment of an attachment according to the invention will now be described in more detail, by way of example only, with reference to the accompanying drawings in which:
FIG. 1 is a front elevation of a fork lift truck attachment according to the invention;
FIG. 2 is a side elevation of the attachment;
FIG. 3 is a plan view of the attachment;
FIG. 4 is a part side elevation, part section of a rotator used in the attachment;
FIG. 5 is a front elevation of the attachment with parts removed;
FIG. 6 is a cross-section through a detail part of the attachment;
FIG. 7 is a cross-section through a hinge;
FIG. 8 is a cross-section through a locking device; and
FIG. 9 is a fluid circuit diagram.
As shown in the drawings the attachment comprises a rear frame 1 provided with mounting members 2 for mounting on the conventional carriage plate of a fork lift truck. Secured to the rear frame by bolts 3 is a back plate 4 of a rotator assembly 5, and secured to the back plate 4 is the outer race 6 of a large diameter ball bearing slewing ring having balls 7. The inner race 8 of this ring is fixed to an annulus 9 which is bolted by bolts 10 to a front member 11 of the rotator assembly.
The rotator assembly includes two hydraulic ram units 12, 13 each secured to the back plate 4 by mounting strips 14 and bolts 15. The two ram units are identical, and only unit 12 will be described in detail, identical components of unit 13 being shown by the same reference numerals with the suffix a. Unit 12 includes two opposed single-acting cylinders 16, 17 in each of which there is a piston 18, 19, the two pistons being joined by a common piston rod 20, part of which is formed with teeth to constitute a rack section 21.
Passing between the two ram units 12, 13 is a hollow shaft 22 carrying at one end a disc 24 secured by bolts 26 to the front member 11 and carrying at the other end a pinion 27 which is in mesh with the two rack sections 21, 21a. The rack sections are shown in their midpositions in FIGS. 5 and 9 but it will be understood that they will normally lie one at an extreme left-hand position and one at an extreme right-hand position. The hollow shaft 22 can rotate about a pin 30 (FIG. 5) having four axial channels 31 to 34 formed therein for carrying hydraulic fluid. The four channels are connected to respective ones of four pipes 35 to 38 which are in turn connected to pipes 39 to 42 leading to a connection block 43 mounted on the rear frame.
The four channels 31 to 34 each open into an annular groove 44 to 47 formed around the pin 30 and communicating with channels 48 to 51 formed in the inner surface of the hollow shaft 22. These channels communicate with axial passages 52 to 55 through the shaft 22, hose connection nipples being provided at the ends of these passages.
Hydraulic fluid lines and 61 are connected to the cylinders 16 and 17a, these lines being connected and passing to a surge prevention valve 64 and thence to the connection block 43. Hydraulic fluid lines 62 and 63 are connected to the cylinders 17 and 16a, these lines being connected and passing to the valve 64 and connection block 43. It will be understood that when hydraulic fluid is admitted into opposite cylinders of the ram units the rack sections 21, 21a will move and will rotate the pinion 27, so causing the front member 11 to rotate relative to the back plate 4.
Secured to the front member 11 of the rotator assembly is a mid-frame 70, and secured to the mid-frame is a front plate which is hinged about an axis 76 to a carrier plate 77. The front plate 75 thus may be pivoted away from and towards the mid-frame 70 by two vertically spaced hydraulic rams 81 and 82, each comprising a cylinder 83, 84 pivoted to the carrier plate 77 and a piston rod 85, 86 pivoted to the front plate 75.
The cylinders are identical, and each cylinder terminates in a stem 11 1 (FIG. 7) which fits between two opposed clevis sections 109, on the carrier plate 77, the stem and clevis being drilled to receive a hinge pin 112 formed to have lands and grooves and also formed to have axial passages for fluid transmission. The clevis sections 109, 110 are each drilled to form a fluid passage 113, 114, the passages being tapped at 115, 116 to receive hose connections, and being closed by plugs 115a, 1160 at their other ends. Passages 115 and 116 are connected respectively by flexible hose, 140, 141
to the hose connection nipples at the ends of passages 52 and 53. The cylinder stem 111 is formed with two fluid passages 117, 118, one opening directly into the flxed end of the cylinder, and the other opening out of the stem into a conduit 121. The passages 117, 118 are drilled through from the exposed edge of the stem and these ends are then plugged by plugs such as 120. The conduit 121 is secured externally of the cylinder and leads to the rod end of the cylinder where it is connected to a port in the cylinder wall opening into the rod end of the cylinder.
The passage 113 in clevis section 109 is aligned with and opens into a groove 123 in the hinge pin, and this groove communicates by an axial passage 124 with a further groove 125 sligned with the fluid passage 117. A passage for fluid through the hinge pin from clevis section 109 to cylinder 83 is thus formed whatever the relative position of the parts. Similarly, groove 126, axial passage 127 and groove 128 form a passage for fluid from clevis section 109 to cylinder 83. Other grooves formed round the hinge pin house O-ring seals 129 for preventing fluid leakage along the outside of the pin. The pin is also formed with grooves 130, 131 receiving circlips 132, 133 for properly locating the pin and holding it in position relative to the clevis sections 109 and 110. The axial passages 124 and 127 are drilled in from opposite ends of the hinge pin and the open ends closed by plugs 134 and 135.
The carrier plate 77 is fitted with upper and lower pairs of rollers and 146 which run on tracks 147 and 148 respectively formed on the mid-frame 70. The carrier plate also has key sections 149 and 150 engaging in parallel keyways 151 and 152 formed on the midframe 70.
Secured to the mid-frame 70 are two hydraulic rams 218 and 219 each having a piston rod with a chain wheel such as 220 mounted on the end thereof. A chain 221 extends from a fixed point 222 above ram 218, around the chain wheel of ram 218 from this chain wheel to the chain wheel 220 of ram 219 and is anchored at 223 below the ram 219. At a point on its run 224 between the two chain wheels the chain is anchored to the carriage plate 77. Thus by extension and retraction of the rams 218 and 219 the carriage plate 77 can be driven longitudinally along the mid-frame 70. The cylinders 218 and 219 are connected respectively by pipes 142, 143 to the hose communication nipples at the ends of passages 54 and 55.
Secured to a first longitudinal edge 225 of the front plate 75 are two clevis mounting members 226 and 227 between which fit bosses of load handling forks 228 and 229 respectively, hinge pins passing through the associated clevises and bosses to pivotally mount the forks on the front plate 75. A similar arrangement of clevises 228a and 229a is provided on the second longitudinal edge 230 of the front plate 75 and in these clevises are pivotally mounted bosses of further forks 231 and 232. The pivotal axes of the forks on the clevises 226, 227, 228a and 2290 are inclined to the longitudinal edges 225, 230 of the front plate 75 so that forks 228 and 231 will not contact each other when moving about their pivots and similarly forks 229 and 232 will not contact each other during pivotal movement.
A locking device 176 is mounted on the mid-frame 70 for locking the front plate 75 to the mid-frame. The lock is fluid-operated, being controlled by fluid pressure in conduit 140. The lock comprises a substantially rectangular housing 178 having mounting flanges 179 by way of which it may be bolted to the mid-frame. Slidably mounted in a chamber 180 in the housing is a plunger 181 having a latching end 182 normally projecting through a slot 183 in one end of the housing. The other end of the housing is closed by a cover plate 184 secured by bolts 185, the cover plate having a slot 186 through which a stern 187 of the plunger projects. A compression spring 188 surrounds that part of the stem 187 that lies within the housing and biases the plunger so that the latching end 182 projects. Formed in the housing are two cylinders 189 and 190, each hav ing a piston 191, 192 slidable therein. Tapped bores 193, 194 open into the cylinders and fluid conduit connectors (not shown)are screwed into the open ends of thetapped bores and connected to the fluid supply conduit 100. It will be evident that when fluid under pressure is admitted into the cylinders 189, 190, the plunger will be moved against the spring 188 to withdraw the latching end 182 into the housing. The latching end 182 of the lock 176 is engageable with the edge of the front plate 75.
Operation of the attachment will now be described. This operation is effected by three controls, a lever 250 controlling a valve 251 for fluid to the rotator cylinders 16, 16a, 17, 17a, a lever 252 controlling a valve 253 for fluidto the cylinders 218, 219 controlling traversing movement of the carrier 77 and front plate 75, and a push-button 254 controlling a valve 255 for fluid to the cylinders 81 and 82 for pivoting the front plate on the carrier.
In operation when a fork lift truck to which the attachment is fixed is operating in its normal state with the forks pointing straight ahead then the attachment appears as shown in solid lines in FIGS. 1 to 3. If it is desired to handle a load to the right hand side of the fork lift truck looking forward from the driving seat then lever 252 is moved to the right to allow fluid to, flow through valve 253 to lines 42 and 143 to move the piston in cylinder 219 to the left hand side of the attachment, so causing'the carrier 77 to traverse across the mid-frame 70, carrying with it the front plate 75. During this movement, fluid exhaustsfrom cylinder 218 through lines 142 and 41.'Simultaneous operation of button 254 will allow fluid to flow through valve 255 to lines 39 and 140 to extend the pistons in cylinders 81 and 82 and so pivot the front plate 75 forwardly on the carrier 77, fluid exhausting from behind the pistons in cylinders 81 and 82 through lines 141 and 40. Carrying out these traversing and pivotal movements simultaneously ensures that the forks 231 and 232 will turn within the longitudinal confines of the attachment and will finally take up the positions shown as 231a and 232a in FlG. 3. When in this position the forks can be moved to project to the right hand side of the truck by moving lever 252 to the left to change over valve 253 and cause fluid to extend the piston in cylinder 218 while fluid is exhausted from cylinder 219. This causes traversing of the carrier frame 77 across the mid-frame 70 back to the right hand side thereof to place the forks in positions 231b and 232b as shown in FIGS. 1 and 3. A load can thus be engaged by the forks in this position and after engagement of the load this may be tilted towards the attachment by a small rotational movement of the mid-frame 70 relative to the rear frame in a clockwise direction as shown in FIG. 1 to raise the forks to the position 232C shown in FIG. 1. The rotation is effected by moving lever 250 to the right so that valve 251 directs fluid into cylinders 16 and 17a, and allows exhaust of fluid from cylinders 17 and 16a.
To convert the attachment to a left side stacking arrangement any load on the forks 231 and 232 is deposited and the front plate 75 is moved to lie parallel with and immediately ahead of the mid-frame if not already in this position.
The lever 250 is then moved to the right so that valve 251 directs fluid into cylinders 16 and 17a, and allows exhaust of fluid from cylinders 17 and 16a. The rack sections 21, 21a thus drive the pinion 25 and so the front plate anticlockwise as seen looking forward from the driving seat, and such rotation is allowed to continue for As the front plate passes'the dead centre position the surge prevention valve 64 acts to prevent any surge of fluid, and allows smooth rotation of the front plate to continue. After inversion it will be seen that the pivotal axis 76 has been moved from the right hand side to the left hand side of the attachment and the front plate has been inverted to place the longitudinal edge 225 lowermost and the longitudinal edge 230 uppermost. During inversion the forks 231 and 232 fall under gravity about their pivotal axes in clevises 228a and 229a to take up a vertical position against the front plate and the forks 228 and 229 fall under gravity about their pivotal axes to take up a horizontal operative position. After the inversion, side stacking to the left may be effected by operation of rams 81, 83 to pivot the front plate away from the mid-frame and operation of rams 218 and 219 to move the carrier plate 77 across the mid-frame. Thus, forks 228 and 229 can be moved to the positions 2280 and 229a shown in FIG. 3. Once again any load on the forks may be tilted towards the centre of the attachment, this time by a small clockwise movement of the mid-frame on the rear frame.
Conversion to right side stacking is of course carried out in similar manner to that described, but controlling valve 251 so that fluid is admitted to cylinders 16a and 17 and exhausted from 16 and 17a so that the midframe rotates through 180 clockwise on the rear frame. v
The attachment thus provides facilities for stacking to left or right of the fork lift truck without impeding normal forward position operation of the truck. The attachment also allows loads to be tilted towards the centre of the attachment to improve stability.
Although a rotator using racks and a central pinion has been described, it will be understood that other types of rotator may be used. For example the midframe may carry an externally toothed ring engaging a pinion rotatably mounted on the rear frame, the pinion being driven directly or through a reduction gear box from an hydraulic motor.
What I claim is:
1. An attachment for a lifting vehicle, comprising a rear frame having means for attachment to. a vehicle, a mid-frame rotatably mounted on the rear frame for rotation relative thereto about an axis substantially perpendicular to the plane of the rear frame, a front plate hinged at one side thereof to the mid-frame, means for opening and closing the hinge to pivot the front plate away from and towards the mid-frame, means for moving the hinge longitudinally of the mid-frame from side to side thereof and mounting means at both opposite longitudinal edges of the front plate to which material handling members may be attached.
2. An attachment according to claim 1 in which the attachment means are means for securing the rear frame to the standard carriage plate of a fork lift truck.
3. An attachment according to claim 1 in which first fluid-operated means are mounted on the rear frame, rack sections are operatively connected to said first fluid operated means to be driven longitudinally across the rear frame, a pinion engages said rack sections and is secured to said mid-frame whereby longitudinal movement of said rack sections causes said rotation of said mid-frame relative to said rear frame.
4. An attachment according to claim 3 in which the means for opening and closing the hinge are second fluid-operated rams having cylinders pivotally secured to a carrier plate movable longitudinally of the midframe from side to side thereof, and piston rods pivotally secured to the front plate.
5. An attachment according to claim 4 in which the carrier plate is moved longitudinally of the mid-frame by third fluid-operated rams.
6. An attachment according to claim 5 in which the third fluid-operated rams comprise two oppositely extending rams one above and longitudinally offset from the other, each having a cylinder secured to the midframe and a piston rod carrying a pulley at its free end, and a flexible element extends from an anchorage above the upper cylinder, around the pulley of the upper piston rod, between the levels of the piston rods, around the pulley of the lower piston rod and to an anchorage below the lower cylinder, the flexible element being secured to the carrier plate in its run between the two pulleys.
7. An attachment according to claim 5 in which the pinion is fixed to a hollow shaft rotatably mounted about a pin secured to the rear frame, and fluid for the second and third fluid-operated rams is transmitted from conduits on the rear plate to conduits on the midframe by communicating axial and radial channels formed in the pin and the hollow shaft.
8. An attachment according to claim 5 in which supply of fluid to the second and third fluid-operated rams is controlled so that whenever there is pivotal movement of the front plate away from the mid-frame there is simultaneous longitudinal movement of the carrier plate on the mid-frame.
9. An attachment according to claim 1 in which the mounting means for the load handling members include hinges to which the load handling means are secured so that when the hinges are on the uppermost edge of the front plate the load handling members hang down substantially parallel to and in contact with the front plate, and when the hinges are on the lowermost edge of the front plate the load handling members project forwardly from the front plate and substantially normal thereto.
10. An attachment according to claim 9 in which the pivotal axes of the hinges are inclined to the longitudinal edges of the front plate so thatload handling members mounted on the hinges will not contact each other when moving about their hinges.