US3738512A

US3738512A - Material handling equipment

Info

Publication number: US3738512A
Application number: US00223224A
Authority: US
Inventors: G Marsden
Original assignee: BARKER R AND CO Ltd
Current assignee: BARKER R AND CO Ltd
Priority date: 1972-02-03
Filing date: 1972-02-03
Publication date: 1973-06-12
Anticipated expiration: 1990-06-12

Abstract

An attachment for a lifting vehicle, particularly a fork lift truck, comprising a rear frame having means for attachment to a vehicle; a mid-frame; a first hinge between the rear frame and mid-frame; means for opening the first hinge to pivot the midframe away from and towards a first lateral side of the attachment, and for closing the first hinge; means for moving the first hinge laterally back and forth across the rear frame; a front plate having attachment points for one or more material handling members; a second hinge between the mid-frame and the front plate; means for opening the second hinge to pivot the front plate away from the mid-frame and towards a second lateral side of the attachment, and for closing the second hinge; and means for moving the second hinge laterally back and forth across the mid-frame. The load handling member may thus be moved to work in a straight-ahead position or a position pointing to either side of a vehicle to which the attachment is fitted.

Description

United States Patent [1 1 Marsden MATERIAL HANDLING EQUIPMENT [75] Inventor: Geoffrey Marsden, Ackworth,

Pontefract, Yorkshire, England [73] Assignee: R. E. Barker & Co., Limited,

Featherstone, Yorkshire, England 22 Filed: Feb. 3, 1972 211 Appl. No.: 223,224

[52] US. Cl. 214/730 [51] Int. Cl 1366f 9/14 [58] Field of Search 214/730, 750, 731

[56] References Cited UNITED STATES PATENTS 2,945,610 7/1960 Wendt 214/730 3,659,733 5/1972 Sinclair et al 214/730 Primary Examiner-Gerald M. Forlenza Assistant Examiner-Lawrence J. Oresky Attorney-Richard K. Stevens et al.

[ 1 June 12, 1973 57 ABSTRACT An attachment for a lifting vehicle, particularly a fork lift truck, comprising a rear frame having means for attachment to a vehicle; a mid-frame; a first hinge be tween the rear frame and mid-frame; means for opening the first hinge to pivot the mid-frame away from and towards a first lateral side of the attachment, and for closing the first hinge; means for moving the first hinge laterally back and forth across the rear frame; a front plate having attachment points for one or more material handling members; a second hinge between the mid-frame and the front plate; means for opening the second hinge to pivot the front plate away from the mid-frame and towards a second lateral side of the attachment, and for closing the second hinge; and means for moving the second hinge laterally back and forth across the mid-frame. The load handling member may thus be moved to work in a straight-ahead position or a position pointing to either side of a vehicle to which the attachment is fitted.

15 Claims, 9 Drawing Figures PATENIEB JUN] 2 ma SHEET 1 [IF 8 PAIENIE JUN 1 2191s sum 2 or a PAIENImJum zms SHEEN; 0F 8 PATENIEB JUN] 2 I973 SHEET 5 0F 8 PATENIED JUN] 2 I973 3 738 5 1 2 SHEET 6 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 directly mounted in the carriage plate which is slidably mounted for vertical movement up and sown 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 lift trucks or attachments therefor which will provide this facility. One proposal has been to provide a rear frame for attachment to the truck, a mid-frame and a front frame bearing the load carrier, the midframe being pivoted at opposite ends thereof respectively to the rear and front frames. The front frame and thus the load carrier could thus be pivoted to either side of the truck. However, the load carrier would always follow an arcuate path, which is a disadvantage, as an aisle in which the truck works would then have to be sufficiently wide to accommodate the width of the truck and the full projection of the load carrier. In other earlier arrangements a rear frame for attachment to the truck has had an element mounted thereon for sliding movement transverse to the truck, the element bearing the load carrier. The load carrier has either been fixed pointing to one side of the truck, or pivoted to move between a straight-ahead position and a position pointing to one side only of the truck. Each such arrangement has limitations in that the load carrier can only work at one side of the truck.

In order to overcome this disadvantage a further proposal has been to provide an attachment comprising a rear frame for attachment to the truck, a mid-frame slidable on the rear frame transversely of the truck and a front frame mounted by releasable pivots at each side of the mid-frame. By releasing the appropriate pivot and leaving the other one locked the front frame could be pivoted about the locked pivot to the respective side of the truck, and could have a limited degree of movement sideways of the truck by sliding the mid-frame on the rear frame. The combined locking and pivot mechanism necessary for such arrangements is cumbersome and complex, and the attachment is accordingly heavy and limited in its operation, particularly as the sliding movement to either side is limited to somewhat less than half the width of the mid-frame.

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; a first hinge between the rear frame and mid-frame; means for opening the first hinge to pivot the mid-frame away from and towards a first lateral side of the attachment, and for closing the first hinge; means for moving the first hinge laterally back and forth across the rear frame; a front plate having attachment points for one or more material handling mem bers; a second hinge between the mid-frame and the front plate; means for opening the second hinge to pivot the front plate away from the mid-frame and towards a second lateral side of the attachment, and for closing the second hinge; and means for moving the second hinge laterally back and forth across the midframe.

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 attach ment means on the rear frame are means for securing that frame to the standard carriage plate of the fork lift truck. The front plate may have attachment points for any contemplated variety of forks, arms and other material handling members.

In use, assuming that the attachment is fitted to the standard carriage plate of a fork lift truck and that the front plate is fittedwith forks, then, when the hinges are closed and in their normal position on the two frames the frames and the front plate are folded flat one immediately ahead of another and within the same lateral confines. The forks on the front plate point directly forward and the truck operates as a conventional fork lift truck. The attachment does not impede this normal operation, or does it impede the conventional side shifting of the forks, and the attachment as a whole, to right or left of the longitudinal center line of the truck while maintaining the forks in a forward pointing direction.

Assume now that, looking forward from the driving position the first hinge is at the left hand side of the rear frame, the second hinge is at the right hand side of the mid-frame and it is desired to side stack to the left of the truck. To do this the first hinge is opened to move the mid-frame and front plate together about the hinge to take up a position projecting forwardly from, and at right angles to, the rear frame. The forks then project to the left of the truck, and by traversing the first hinge across the rear frame from its limit left hand to its limit right hand position the forks can be moved between positions projecting beyond the lateral confines of the rear frame and lying substantially within those confines. If side stacking to the right is required, then the second hinge is opened to move the front plate relative to the mid-frame to take up a position extending forwardly from the mid-frame and at right angles to the mid and rear frames. The forks then project to the right of the truck and can be moved to lie substantially within the lateral confines of the plates by moving the second hinge to the left across the face of the midframe.

The arrangement according to the invention differs from the prior known arrangements in that the hinges are themselves slidably movable on the respective frames and the range of movement of the attachment within the lateral confines of the truck is substantially increased over the previous arrangements, without the need for complex and heavy locking mechanisms. The saving in weight is, of course, of great importance since it reduces the load on the mast of the fork lift truck and allows an increased load weight to be carried. The invention thus provides a more versatile, lighter and simpler arrangement for converting a fork lift truck to have a side-stacking capability.

Preferably the attachment is such that pivotal movement of the mid-frame away from the rear frame occurs simultaneously with lateral movement of the first hinge across the rear frame, and that pivotal movement of the front plate away from the mid-frame occurs simultaneously with lateral movement of the second hinge across the mid-frame.

By carrying out these simultaneous movements it is possible to turn load carrying members secured to the front plate from a forward facing to a side facing position while maintaining the load carrying members entirely within the confines of width of the attachment. Conversion to side-stacking can thus be effected in narrower aisles than was possible in prior constructions Preferably, first and second locks are provided for locking respectively the mid-frame to the rear frame at the second lateral side, and for locking the front plate to the mid-frame at the first lateral side. Conveniently the locks may be linked to the hinge opening means so that the first lock is released before the first hinge is opened and the second lock is released before the second hinge is opened.

Desirably the hinge-opening means, hinge-moving means and locks are all hydraulically operated.

An 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.-l is an end elevation of the attachment with the front plate facing forward;

FIG. 2 is an isometric view of the attachment with the front plate pivoted to one side;

FIG. 3 is an isometric view of the attachment with the front plate pivoted to the other side;

FIG. 4 is a cross section through parts of the rear and mid-frames in the direction of the arrow A;

FIG. 5 shows a detail of a hinge plate;

FIG. 6 is a cross-section through a hinge;

FIG. 7 is a cross section through a hinge detail;

FIG. 8 is a cross section through a locking device; and

FIG. 9 is a fluid circuit diagram.

Referring now to the drawings, and in particular to FIGS. 1 to 3, the attachment comprises a rear frame 1, a mid-frame 2 and a front plate 3. The rear face of the rear frame is provided with mounting members 4 whereby the attachment may besecured to the conventional carriage plate of a fork lift truck. The front plate includes two

bars

5 and 6 having upper and

lower edges

7 and 8 respectively of angle section to form a standard carriage plate on which a load handling member may be mounted, for example a pair of forks 9 as shown in broken lines in FIG. 1.

The mid-frame 2 is formed with

webs

10 and 11 projecting above the upper and lower edges respectively of the frame. The upper edge of the frame and the upper web 10 form a clevis to which is secured a hinge pin 12 passing through a self-lubricating bush (not shown) mounted in a boss 13 carried at the endof a substantially triangular web 14 forming part of a carrier plate 15. The lower edge of the frame and the lower web 11 form'a similar clevis cooperating with a boss 16 carried by a web 17 forming part of the carrier plate 15. Again a hinge pin is secured to the clevis coaxial with hinge 12, the hinge pin being rotatable in a self-lubricating bush within the boss 16. The mid-frame 2 is thus hinged to the carrier plate and can move between a closed position wherein the mid-frame lies immediately in front of the rear frame (as shown in FIG. 1) and an open position with the mid-frame extending forwardly substantially at right angles to the rear frame, as shown in FIG. 2.

Pivotal movement between these positions is effected by two fluid-operated

rams comprising cylinders

18 and 19 pivoted to the carrier plate at 20 and 21 respectively, and pistons having

piston rods

22 and 23 pivoted at 24 and 25 respectively to the mid-frame.

The carrier plate 15 is mounted for movement back and forth across the rear frame 1 in the following manner, shown most clearly in FIG. 4. The rear frame 1 is formed along its upper and lower edges with

tracks

26 and 27 respectively. Rotatably mounted at the upper part of the carrier plate 15 are

rollers

28 and 29 running on the upper face '30 of the track 26. Roller 28 is formed with a flange 31 engaging the front face 32 of the upper track 26, and is rotatably mounted by bearings 33 about a pin 34 secured between

plates

35 and 36 forming part of the carrier plate 15 and lying respectively to the front and rear of the track 26, the

plates

35 and 36 being joined by a web 37. The rear plate 36 has a transverse extension 38 into which is screwed a further pin 39 surrounding which is a further bearing 40 supporting a roller 41 for rotation. The roller 41 runs on the rear face 42 of the track 26. The roller 29 is also flanged and is mounted for rotation in an identical manner to the roller 28. Roller 41 is mounted close to roller 28, and a roller similar to roller 41 is mounted close to roller 29.

The lower part of the carrier plate 15 is formed by a plate 43 welded to the remainder of the carrier plate and rotatably supporting

rollers

45 and 46 running on the lower face 47 of the lower track 27. The

rollers

45 and 46 are mounted on the plate 43 in identical manner. Thus, roller 45 is supported by bearings 48 mounted on a supporting bolt 49 passing through a hole 50 in the plate 43 and secured by a nut 51. A spacing boss 52 is welded to the plate 43, the bolt 49 passing through a bore 53 in the boss, and a spacing washer 54 is positioned between the inner race of the bearing 48 and the head 55 of the bolt to ensure that the head 55 can not engage the roller 45. The roller 45 is formed with a flange 56 engaging the rear face 57 of the track 27.

At two spaced locations between the

rollers

45 and 46 further rollers such as 58 are rotatably mounted on the carrier plate 15 to run on the front face 59 of the lower track 27. To accommodate each such roller 58 the plate 43 is cut away to receive a socket 60 bolted by a bolt 61 to the remainder of the carrier plate 15 and having a tapped bore 62. Received in this bore is the end of a bolt 63 on which is axially secured a bearing 64 supporting the roller 58 for rotation. The roller 58 and the head of the bolt 63 are also accommodated in the cut-away section of the plate.

It will thus be seen that the carrier plate 15 is mounted for free movement across the rear frame. The

rollers

41 and 58 engaging behind and in front of the upper and lower tracks respectively prevent the midframe from pulling away from the rear frame when a load is being carried and ensure smooth movement of the carrier plate 15 and mid-frame across the rear frame even under load. The flanges 31 and 56 on

rollers

28, 29 and 45, 46 respectively prevent the carrier plate 15 from pulling off the

tracks

26 and 27 by a forward movement of the lower part thereof, such as could be caused by accidental contact of the attachment with the ground.

The carrier plate 15 is moved laterally across the rear frame 1 by two single-acting fluid-operated rams. The first of these rams comprises a cylinder 65 mounted on the rear frame and a piston having a piston rod 66. The

second such ram comprises a cylinder 67 mounted on the rear frame below the level of the cylinder 65, and a piston having a piston rod 68. The two cylinders are fixed at opposite lateral sides of the rear frame and the piston rods extend in opposite directions across the frame. The

piston rods

66 and 68 each carry a pulley 69 and 70 respectively at their free ends. A chain 71 is anchored at one end 72 above the cylinder 65, passes round the pulley 69, round the pulley 70 and is anchored at its other end 73 below the cylinder 67. On its run 74 between the two pulleys the chain is anchored to the carrier plate as shown in FIG. 5. Referring to this Figure the plate 15 has a mounting element 75 secured to the rear surface thereof by four set screws such as 76. The two sections of the run 74 of the chain are respectively anchored to an anchor plate 77 of the mounting element 75 by pins 78 passing through bores 79 in the anchor plate and also passing through links of the chain. The chain may be continuous or may be discontinuous, the two parts thus being joined by the anchor plate.

The front plate 3 is mounted for pivotal movement and lateral movement relative to the mid-frame 2 in a manner similar in many respects to that already described for the mounting of the mid-frame relative to the rear frame. Thus the front plate is provided with upper and lower axially aligned

hinge bosses

80 and 81, each surrounding a self-lubricating bush which in turn surrounds a hinge pin secured across the clevis formed respectively between the upper edge of a carrier plate 82 and an upper web 83 projecting therefrom, and between the lower edge of the carrier plate 82 and lower web 84 projecting therefrom. Pivotal movement of the front plate 3 on the carrier plate 82 is effected by two fluid operated

rams comprising cylinders

85, 86 having pistons and

piston rods

87, 88 respectively, the cylinders being pivotally mounted at 89 and 90 to the carrier plate 82 and the piston rods being pivotally mounted at 91 and 92 to the front plate 3.

The carrier plate 82 is mounted for sliding movement across the mid-frame by upper and lower cooperating slides and slideways, the two assemblies being inverted one with respect to the other but otherwise being identical. The upper slide assembly comprises a squaresection member 93 secured along the upper edge of the mid-frame 2, the member 93 being formed with a longitudinally extending cylindrical bore 94 and a longitudinally extending slot 95 directed radially from the bore 94 at the lower extremity thereof. Secured to the carrier plate 82 is a slide carrier 96 carrying either a single cylindrical member extending the length of the slide carrier 96, or two or more shorter, spaced cylindrical members 97. In each case the cylindrical member or members has a surface of self-lubricating material and is a close fit in the slideway formed by the bore 94, the slide carrier 90 extending through the slot 95. Visible parts of the lower slide and slideway, identical to parts of the upper assembly, are shown on the drawings by the same reference numerals as for the parts of the upper assembly, with the suffix a. The disposition of the slides and slideways are such that the carrier plate is held out of all contact with the mid-frame, except for the slide and slideway contact.

Sliding movement of the carrier plate 82 and thus the front plate 2 across the mid-frame is effected by two single-acting

rams having cylinders

98, 99 and

piston rods

100, 101 carrying

pulleys

102, 103 around which passes a chain 104 anchored to the mid-frame at its ends 105, 106 above cylinder 98 and below cylinder 99 respectively, and anchored to the carrier plate in the same fashion as chain 71 is anchored to carrier plate 15 (FIG. 5).

It will now be evident that in order to operate all the fluid-operated rams, fluid must be fed through from the rear frame to the mid-frame, and to both ends of the rams for pivoting the mid-frame and front plate. To allow this fluid feed, the

hinges

20,21, 89 and for the

cylinders

18, 19, 85 and 86 are all constructed as shown in FIG. 6, and hinges 107, 108 coaxial with the main hinges between the carrier plate 15 and the midframe 2 are of similar construction.

FIG. 6 shows, as an example of one of these hinges, the hinge 20 in the position with the cylinder 18 lying against the rear frame 1, Le. with the hinge closed. The carrier plate 15 is formed with two

opposed clevis sections

109, 110 between which there fits a stem 111 formed on the end of the cylinder 18. The stem and the clevis are 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, 116a at their other ends. The cylinder stem 111 is formed with two

fluid passages

117, 118, one opening directly into the fixed end of the cylinder, and the other opening out of the stern 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 aligned with the fluid passage 117. A passage for fluid through the hinge pin from clevis section 109 to cylinder 18 whatever the relative position of the parts. Similarly, groove 126, axial passage 127 and groove 128 from a passage for fluid from clevis section 109 to cylinder 18. 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 form opposite ends of the hinge pin and the open ends closed by

plugs

134 and 135.

Hinges 21, 89 and 90 are identical to that described above.

Hinges

107 and 108 differ therefrom only in detail of the hinge ends and circlip grooves, the other grooves and axial passageways being identical to those described. However, as there is no cylinder such as 20 associated with such hinges an end block 136 as shown in FIG. 7 is mounted between the clevis portions of the hinge, which form part of the mid-frame, and is secured to the carrier plate 15. The end block 136 has

fluid passages

137, 138 aligned with the

grooves

125, 128 of the hinge pin and opening into tapped

holes

139, 140 into which hose connection nozzles may be screwed.

The remainder of the fluid connections will now be described in relation to FIG. 2, 3 and 8. The movements of the attachment are controlled from the drivers position of the fork lift truck by a single lever 141 controlling a three-position valve 142, and a push-button 143 mounted on the end of the lever and operative to complete an electrical circuit to the solenoid of a twoposition solenoid valve 144. The lever 141 is movable from a central position to the left or right of the truck, to control lateral shifting of the frames to the appropriate side of the truck. Power is taken from the standard hydraulic system of the fork lift truck through power and drain conduits 145 and 146, branches 147 and 148 of which lead to valve 144. Two conduits from valve 142 and two from valve 144 are connected by flexible hoses to a mounting block 149 on the rear frame 1 of the attachment, and four corresponding conduits from the valves are connected by flexible hoses to a second mounting block 150 on the rear frame. Each mounting block comprises two sequence valves 151 to 154 each having a non-return valve 155 to 158 in parallel therewith, and appropriate connectors.

From the mounting block 149 rigid conduits 159 and 160 (for example steel tubes) extend respectively to

cylinders

65 and 67. The mounting block is connected to the opposite ends of the

cylinders

18 and 19 by

conduits

161 and 162, which comprise sections of

rigid conduit

161a, 162a leading from the block 149 to a connection box 163, and section of

flexible hose

161b, 162b leading from the connection box 163 to the

clevis sections

109, 110 of binge 20, these clevis sections being interconnected with those of the clevis sections of hinge 21 by rigid conduits 164, 165.

From the mounting block 150 conduits 166 to 169 are connected respectively to

cylinders

98, 99 and to opposite ends of

cylinders

85 and 86. Conduits 166 to 169 each comprise rigid conduit sections 1660 to 1690 leading to a connection block 170; flexible hose sections l66b to 16912 extending from the block 170,

through a hole 171 in the carrier plate 15 to a connection block 172; and rigid conduit sections 1660 to 169C extending from the block 172 to the end blocks 136 of the

hinges

107 and 108. Conduits 166 and 167 are then continued by rigid conduit sections 166d, 167d to

cylinders

98 and 99.

Conduits

168 and 169 are continued from the clevis sections of hinge 108 by

rigid conduit sections

168d, 169d to a connection box 173, and thence by flexible hose sections 168e, !169e to the clevis sections of hinge 90, these clevis sections being interconnected with those of hinge 89 by

rigid conduits

174 and 175.

Referring now to FIGS. 2 and 3

locking devices

176 and 177 are mounted on the rear frame and mid-frame respectively, the device 176 being for locking the rear frame and mid-frame together, and the device 177 being for locking the mid-frame and front plate together in their closed positions. Each lock is fluidoperated, lock 176 being controlled by fluid pressure in conduit 162, and lock 177 by fluid pressure in conduit 169. Each lock is of identical construction, as shown in H0. 8.

Referring to this Figure, each lock comprises a substantially rectangular housing 178 having mounting flanges 179 by way of which it may be bolted to the respective 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 having 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 the tapped bores and connected to the appropriate fluid supply conduit. 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 a catch rail 195 on mid-frame 2. The latching end of the lock 177 is engageable with the bar 6 of the front plate. Thus, when the

rams

18 and 19 are retracted so that the mid-frame lies against the rear frame the two frames are held together by the lock 176. In this position the two frames are substantially contiguous, but the arrangement is such that the pivot axes at 24 and 25 between the

piston rods

22 and 23 and the midframe lie slightly in front of the pivot axes at 20 and 21 between the

cylinders

18 and 19 and the carrier plate 15. This ensures that pivotal movement of the midframe will commence immediately on extension of the rams. Similarly when the rams between the front plate and mid-frame are retracted the front plate lies immediately ahead of and substantially contiguous with the mid-frame and is held in that position by the lock 177. The pivotal axes at 91 and 92 between the

piston rods

87, 88 and the front plate lie slightly in front of the pivot axes 89 and between the

cylinders

85, 86 and the mid-frame, so that pivotal movement of the front plate commences when extension of the rams is started.

Operation of the attachment will now be described. This operation is effected by means of two controls only, the lever 141 which controls lateral shifting and the push-button 143 which controls pivotal movement. Assuming for the moment that pivotal movement is not required, and that the only action necessary is a lateral shifting of the load carrying members projecting in a straight ahead position, then the only control necessary is lever 141, and push-button 143 is not operated. Lateral shifting to the right hand side of the vehicle, facing forwardly (indicated by the arrow 2 in FIG. 9), is effected by moving control lever 14] to the right so that fluid flow through the valve 142 is effected by the connections in the section 142a of this valve. Fluid pressure is accordingly admitted to conduit 167 and, through sequence valve 152, to conduit 160, the pressure in the former conduit having no effect on the piston in cylinder 99. However, the fluid in conduit moves the piston in cylinder 67 towards the right hand side of the attachment, so causing the carrier plate 15 to traverse across the rear frame 1, carrying with it the mid-frame 2. During this movement, fluid exhausts from cylinder 65 through line 159 and the section 142a of the valve 142. For return movement to the left the lever 141 is moved to the left to make the fluid connections in section 14212 of the valve. This applies fluid under pressure to conduit 159 and, via the delay valve 153, to conduit 166. The delay valve 153 will only open when full system pressure is applied to it, which will not happen until the piston in cylinder 65 has been driven back to its full left hand position by the fluid in conduit 159, fluid from cylinder 67 being exhausted through conduit 160, non-return valve 150 and part 142b of valve 142. This movement returns the carrier plate 15 to its position at the left hand extremity of the rear frame 1, and at this stage the rear frame, mid-frame and front plate are again lying one in front of the other within the same lateral confines. If the lever 141 is moved back to its central position at this time then no further movement occurs. However, if the lever is maintained in the left hand position then full system pressure builds up at the sequence valve 153 and pressure fluid passes to cylinder 98 through conduit 166. This has the effect of driving the piston in cylinder 98 to the left so shifting the carrier plate 82 and front plate along to the left hand end of the mid-frame, in the direction of the arrow L in FIG. 9. During this movement fluid exhausts from cylinder 99 through conduit 167 and the section 142b of valve 142. Movement of the lever 141 to the right will commence movement of the front plate back to its central position, where it can be stopped by centralizing the lever 141 at the appropriate time. During such movement sequence valve 152 prevents flow of fluid to cylinder 67. The attachment thus givesthe fork lift truck a conventional side shift facility to either side of the truck.

Assume now that it is desired to work with the load handling members projecting to the left hand side of the truck. With the mid-frame and front plate in their central positions this is achieved by moving the control lever 141 to the right and at the same time pressing the push-button 143. When this is done fluid under pressure is supplied through section 142a of valve 142 to conduits 160 and 167 as already described, and, via conduit 147 to the valve 144, which has been opened by operation of the push-button 143, and from the valve 144 to conduit 168 and, via sequence valve 151 to conduit 162. As before, fluid pressure in conduit 167 has no effect, and also fluid pressure in conduit 168 will have no effect since the pistons in

cylinders

85 and 86 are already fully retracted. However, fluid pressure in conduit 162 first releases the lock 176 and then moves the pistons in

cylinders

18 and 19 to extend these rams, while at the same time the fluid pressure in conduit 160 extends the ram formed by cylinder 67 and piston rod 68. Thus, the mid-frame pivots on the carrier plate 15 into its left-facing position, fluid being exhausted from

cylinders

18 and 19 through conduit 161, valve 144, conduit 148 and valve section 142a, while at the same time the carrier plate 15 traverses to the right across the rear frame 1. The simultaneity of these two actions means that the load carrying member can be brought into its left-facing position without at any time projecting beyond the lateral confines of the rear frame 1. When the full pivotal movement is completed the pushbutton 143 is released so closing valve 144, whereupon the fluid under pressure locks the

rams having cylinders

18 and 19 in their extended position. Movement of the control lever 141 to the left without operation of the push-button 143 will then cause fluid under pressure to pass to cylinder 65 to drive the carrier plate 15 back to the left hand side of the rear frame so that the load carrying elements are moved to a position to the left hand side of the fork lift truck. Thus, traversing of the load carrying members in their left-facing position can be effected by movement of the control lever 141.

To return the attachment to its normal position the mid-frame is first traversed to its right hand position on the rear frame (if not already there) by making connections 142a through valve 142. Then the control lever is moved to its left hand position to make connections 142b and the push-button 143 is operated at the same time. Thus, fluid under pressure is applied to conduit 159, and, through delay valve 153 to conduit 166, and fluid under pressure is also applied through conduit 148 to valve 144. From this open valve, pressure fluid is applied to conduit 161 and, through the delay valve 154 to conduit 169. As already explained this condition, due to the delay valve 153, has no effect on the piston in cylinder 98, but commences a shift to the left of the piston in cylinder 65, so commencing a left traverse of the carrier plate on the rear frame. Similarly, the delay valve 154 effectively prevents operation of the

rams comprising cylinders

85 and 86, the fluid pressure in conduit 161 causing retraction of the

rams having cylinders

18 and 19, and thus pivoting the midframe back to its position against the rear frame. Once again the pivotal and traversing movements take place simultaneously so that the load carrying members turn within the lateral confines of the rear plate. During this movement fluid exhausts from

cylinders

18 and 19 through conduit 162 and the non-return valve 155, open valve 144 and part 142 b of the valve 142. Simultaneously fluid exhausts from cylinder 67 through conduit 160, the non-return valve 156 and connections 14212 of the valve 142.

It will be understood that when the load carrying members are required to project to the right hand side of the truck movement of the control lever 141 to the left to bring section 142b into operation and simultaneous operation of the push-button 143 will cause extension of

rams having cylinders

85, 86 and 98 in a manner analagous to that described above. The pivotal movement of the load carrying members is thus again effected within the natural confines of the rear frame. When fully pivoted, the push-button 143 is released and traversing movement of the front plate on the midframe can then be effected by appropriate movement of the lever 141. To fold the front plate back into its closed position the control lever 14] is moved to the right and the push-button 143 operated whereupon the rams having cylinders and 86 are retracted and the ram having cylinder 99 is extended, again in a manner analogous to that already described.

It will now be evident that the invention provides an attachment which may be used to give a fork lift truck conventional side shifting facility and alsofacility for stacking to the left and right of the fork lift truck. These objectives are achieved by an attachment of simple construction, and the desired effects can be achieved by a single control lever and control button so making operation of the attachment very easy.

What 1 claim is:

1. An attachment for a lifting vehicle, particularly a fork lift truck, comprising a rear frame having means for attachment to a vehicle; a mid-frame; a first hinge between the rear frame and the mid-frame; means for opening the first hinge to pivot the mid-frame away from and towards a first lateral side of the attachment, and for closing the first hinge; means for moving the first hinge laterally back and forth across the rear frame; a front plate having attachment points for one or more material handling members; a second hinge between the mid-frame and the front plate; means for opening the second hinge to pivot the front plate away from the mid-frame and towards a second lateral side of the attachment, and for closing the second hinge; and means for bodily shifting the second hinge laterally back and forth across and along the longitudinal axis of the mid-frame.

2. An attachment according to claim 1 in which the means for attachment to a vehicle comprise means for securing the rear frame to the carriage plate of a fork lift truck.

3. An attachment according to claim 1 and including first and second locks for locking respectively the midframe to the rear frame at the second lateral side, and for locking the front plate to the mid-frame at the first lateral side.

4. An attachment according to claim 3 in which the locks are linked to the hinge opening means so that the first lock is released before the first hinge is opened and the second lock is released before the second hinge is opened.

- 5. An attachment according to claim 4 in which each hinge is mounted on a carrier plate movable laterally tively and hydraulically operated means for moving the catch against the biasing force to move said catch out of locking engagement.

7. An attachment according to claim 5 in which each ram comprises a cylinder pivoted to the carrier plate and a piston with a piston rod pivoted to the mid-frame or front plate respectively, and each cylinder is pivoted by a stern fitting between two sections of a clevis and a hinge pin passing through the stern and the clevis sections, the hinge pin being formed with passages for feeding hydraulic fluid from bores formed in the clevis sections to bores formed in the cylinder stem and vice versa.

8. An attachment according to claim 5 in which the carrier plate of the first hinge is mounted for lateral movement over the rear frame by rollers journalled at the upper and lower parts of the carrier plate and running respectively on upper and lower faces of upper and lower tracks on the rear frame.

9. An attachment according to claim 8 in which the upper rollers have flanges engaging the upper track on the front face thereof and the lower rollers have flanges engaging the lower track on the rear face thereof.

10. An attachment according to claim 8 in which the upper and lower parts of the carrier plate have further rollers journalled thereon with axes of rotation at right angle to said rollers, the upper further rollers engaging the rear face of the upper track and the lower further rollers engaging the front face of the lower track.

11. An attachment according to claim 5 in which the carrier plate of the second hinge has slides engaging slideways on the front face of the mid-frame to allow the carrier plateto slide laterally on the mid-frame, the slide and slideways interlocking to hold the carrier plate out of any further contact with the mid-frame.

12. An attachment according to claim 5 in which the means for moving the hinges laterally back and forth across the respective ones of the rear frame and midframe each comprise fixed pairs of hydraulic rams, each pair comprising a first hydraulic ram having a cylinder fixed at one lateral side of the plate and extending substantially half-way across the frame, a second hydraulic ram having a cylinder fixed at the other lateral side of the frame below the level of the cylinder of the first hydraulic ram and extending substantially halfway across the frame, each ram having a piston and a piston rod extendable in opposite direction across the frame, the piston rods each carrying a pulley at their free end, and a chain anchored at its ends adjacent to the ends of the cylinders nearer the center of the frame and extending around the pulleys and secured in its run between the pulleys to the carrier plate.

13. An attachment according to claim 12, in which is such that pivotal movement of the mid-frame away from the rear frame occurs simultaneously with lateral movement of the first hinge across the rear frame, and that pivotal movement of the front plate away from the mid-frame occurs simultaneously with lateral movement of the second hinge across the mid-frame.

14. An attachment according to claim 13 wherein said simultaneous pivotal movement of the mid-frame and lateral movement of the first hinge is effected by simultaneous extension of the respective pivotally mounted hydraulic ram, and an appropriate one of the respective fixed pair of hydraulic rams, and said simultaneous pivotal movement of the front plate and lateral movement of the second hinge is effected by simultaneous extension of the other respective pivotally mounted hydraulic ram and an appropriate one of the other respective fixed pair of hydraulic rams.

15. An attachment according to claim 14 and including sequence valves for delaying application of fluid under pressure until the pressure is the full system pressure, said sequence valves controlling fluid flow to extend the pivotally mounted rams and controlling fluid flow to those ones of the respective pairs of fixed rams which extend to give lateral movement of the midframe and front plate respectively from their normal positions directly ahead of the rear frame.

Claims

3. An attachment according to claim 1 and including first and second locks for locking respectively the mid-frame to the rear frame at the second lateral side, and for locking the front plate to the mid-frame at the first lateral side.

5. An attachment according to claim 4 in which each hinge is mounted on a carrier plate movable laterally across the respective frame, each hinge opening means comprises a pivotally mounted hydraulic ram operating between the respective carrier plate and the mid-frame or front plate respectively, and the locks are hydraulically operated.

6. An attachment according to claim 5 in which each lock comprises a catch member biased into locking engagement with the mid-frame or front plate respectively and hydraulically operated means for moving the catch against the biasing force to move said catch out of locking engagement.

7. An attachment according to claim 5 in which each ram comprises a cylinder pivoted to the carrier plate and a piston with a piston rod pivoted to the mid-frame or front plate respectively, and each cylinder is pivoted by a stem fitting between two sections of a clevis and a hinge pin passing through the stem and the clevis sections, the hinge pin being formed with passages for feeding hydraulic fluid from bores formed in the clevis sections to bores formed in the cylinder stem and vice versa.

11. An attachment according to claim 5 in which the carrier plate of the second hinge has slides engaging slideways on the front face of the mid-frame to allow the carrier plate to slide laterally on the mid-frame, the slide and slideways interlocking to hold the carrier plate out of any further contact with the mid-frame.

12. An attachment according to claim 5 in which the means for moving the hinges laterally back and forth across the respective ones of the rEar frame and mid-frame each comprise fixed pairs of hydraulic rams, each pair comprising a first hydraulic ram having a cylinder fixed at one lateral side of the plate and extending substantially half-way across the frame, a second hydraulic ram having a cylinder fixed at the other lateral side of the frame below the level of the cylinder of the first hydraulic ram and extending substantially halfway across the frame, each ram having a piston and a piston rod extendable in opposite direction across the frame, the piston rods each carrying a pulley at their free end, and a chain anchored at its ends adjacent to the ends of the cylinders nearer the center of the frame and extending around the pulleys and secured in its run between the pulleys to the carrier plate.

15. An attachment according to claim 14 and including sequence valves for delaying application of fluid under pressure until the pressure is the full system pressure, said sequence valves controlling fluid flow to extend the pivotally mounted rams and controlling fluid flow to those ones of the respective pairs of fixed rams which extend to give lateral movement of the mid-frame and front plate respectively from their normal positions directly ahead of the rear frame.