AU618678B2 - Push-pull assembly and its platen unit for forklift trucks - Google Patents

Description

Tokyo Jap 4th June90 D eclared at.. th i d ay o f 19 Signed -Status. General Manager S ig n e d S ta t us Hirosuke Imai NIPPON PETROCHEMICALS CO., LTD.

D eclaran t's N a m C' -Bc" I i COMMONWEALTH OF AUSTRALIA Patents Act 1952 COMPLETE SPECIFICATION

(ORIGINAL)

Class Int. Class Application Number Lodged Complete Specification Lodged Accepted Published Priority 13 JUNE 1989, SE£PT lqvi Related Art I a- Name of Applicant Address of Applicant I I NIPPON PETROCHEMICALS CO.LTD and YAMAKAWA ENGINEERING CO LTD 1-3-1, UCHISAIWAI-CHO CHIYODA-KU,TOKYO, JAPAN, and 1265-24, UEKI,SUE-MACHI,

KASUYA-GUN,FUKUOKA-KEN,

JAPAN, respectively.

TADAO SATOH, YOSHIAKI HENMI, RYOZO MATSUMOTO, SHIN SASAKI, and NAOYUKI FUKUSHIMA.

RICE CO., Patent Attorneys 28A Montague Street BALMAIN NSW 2041 Actual Inventor(s) Address for Service Complete Specification for the invention entitled: "PUSH-PULL ASSEMBLY AND ITS PLATEN UNIT FOR FORKLIFT TRUCKS" The following statement is a full description of this invention including the best method of performing it known to us/p i t :i 1 i: r la- This invention relates to a push-pull assembly for use on forklift trucks in transporting sheet pallets and loads deposited thereon. The invention is further 0o concerned with a platen section adapted for attachment to such assembly.

000 0 A push-pull device of the character mentioned is known as seen at 10 in Figure 8. Designated at 11 is a ooo0 fixed frame mounted vertically movably on a mast of a oforklift truck not shown. A platen 13 is firmly secured 00 on one side to the fixed frame 11 at its lower end so as to support thereon a sheet pallet not shown and a load carried thereon. A movable frame 9 held in vertically bo, movable relation to the fixed frame 11. To the movable frame 9 are connected the rear couplings of a pantographic linkage 14. Up-and-down motion of the movable frame 9 provided by a first cylinder 15 allows the linkage 14 to ascend and descend in unison with the frame 9.

A push plate 12 is connected to the front 3nrm3C*~-I 2 couplings of the linkage 14. The push plate 12 is thus movable toward and away from the fixed frame 11 in response to retrac' ion and extension of the linkage 14 powered by a second cylinder not shown. The push plate 12 includes a pallet clamper 16 which has a first jaw 19 fixed to a lower edge of the plate 12, a third cylinder 17 underlying the plate 12 and a second jaw 20 secured to a piston rod 18 of the cylinder 17. The jaws 19, o0 cooperate with each other in grasping therebetween the no 10 sheet pallet.

oa Designated at 21 is a presser fixedly connected to 0 a bottom portion of the movable frame 9 so as to press the pallet against the platen 13.

In transporting the load carried on the sheet 15 pallet, the pallet is arrested by the clamper 16, 0o991o whereupon the push plate 12 is caused to cearwardly move 6O 0 .so that the load is pulled onto the platen 13 together with the pallet. By subsequent actuation of the cylinder 15, the frame 9, the linkage 14, the plate 12, 4 1*I 20 the presser 21 and the clamper 16 in their entireties are raised while the cylinder 17 is manipulated to disengage the pallet from the clamper 16. The cylinder is again actuated to lower the frame 9, the link 14, the plate 12, the presser 21 and the clamper 16 with the result that the pallet is urged by the presser 21 against the platen 13. The plate 12 is allowed to move forwardly to remove the load alone. The pallet is thus L. -i 3 shifted back.

The above push-pull device, however, is literally energy-consuming as it is necessary to raise of the frame 9, the linkage 14, the plate 12, the presser 21 and the clamper 16. Vertical movement of the pantoghraphic linkage involves complicated construction.

The present invention therefore seeks to provide a S"0 new push-pull assembly for forklift trucks which is o 10 simple in construction and capable of efficient pallet recovery with reduced power. The invention also seeks 0o to provide a platen unit for use on the push-pull assembly.

One aspect of the invention provides a push-pull 15 assembly for use on forklift trucks which comprises: a carriage mounted vertically movably on a mast of a forklift truck and provided at a lower end thereof with a platen having a surface for supporting thereon a sheet pallet and a load deposited on the pallet; retractable and extensible means comprising a rear coupling portion 4I mounted on the carriage and a front coupling portion movable rearwardly and forwardly with respect to the rear coupling portion; face means connected to the front coupling portion of the retractable and extensible means and comprising a face member supportive of the load and grip means movable between a first position in which it is close to the load-supporting surface of the platen 4 and a second position in which it is remote from the load-supporting surface, the grip means capable of clamping the sheet pallet in the first position; and press means for pressing the sheet pallet against the lift means, the press means comprising means movable between the first and second positions and rotatable to press the sheet pallet against the carriage in the first position and rotatable to move the grip means into the second position, and means for selectively actuating the Ott.

~1oo 0 rotating means between the first and second positions.

0o 0 Another aspect of the invention provide a platen o0 section adapted to be releasably mounted on a push-pull assembly for use on forklift trucks, which comprises: a frame mounted vertically movably on a mast of a forklift ooo0 15 truck; a platen unit removably attached to the frame and 0000 o comprising a platen having a load-supporting surface to support thereon a sheet pallet and a load carried on the pallet, and press member movable between a first position in which it is adjacent to the load-supporting 0A0I .oat 20 surface of the platen and a second position in which it 0* I is remote from the load-supporting surface, the press means capable of pressing the sheet pallet against the platen in the first position, the press means including actuating means for selectively moving the press member between the first and second positions; and means for holding the platen unit in interengaged relation to the frame1 f ame, I; L 5 Many other objectives and advantages of the invention will become readily apparent upon reading the following description in conjunction with the accompanying drawings in which like reference numerals refer to like or corresponding parts.

Figure 1 is a schematic view of the whole forklift truck to which a first embodiment of the present invention has been applied; Figure 2 is a side elevational view showing the 4 t push-pull assembly with its pantographic linkage shown .fully extended; Figure 3 is a side elevational view showing the pantographic linkage in fully retracted position; Figures 4 is a segmentary elevational view of the 15 pantographic linkage showing the manner in which second and third sliders are positionally associated with first and second stoppers when the linkage has been extended; Figure 5 is a segmentary elevational view of the pantographic linkage showing the manner in which second *'er 20 and third sliders are positionally associated with first and second stoppers when the linkage has been retracted; Figure 6 is a side elevational view of a platen section according to the invention shown integral with the push-pull assembly of Figure 1; Figure 7 is a perspective view of the platen section; and i 6 Figure 8 is a side elevational view showing a prior art device.

Referring now to Figures 1 to 5, a push-pull assembly constructed in accordance with a first embodiment of the present invention will be described.

Shown at M in Figure 1 is a mast of a forklift truck on which a carriage 100 is mounted. The carriage 100 comprises a frame 101 arranged to move vertically .o along the mast M, and a platen 104 fixedly attached at 4oP 10 one end to a lower end of the frame 101 and adapted to o 0 Oo support thereon a sheet pallet P and a load L carried on a o that pallet. To the frame 101 are connected two couplings 105a, 105c of a retractable and extensible pantographic linkage 105 as shown in Figure 2. Two ^o t 15 front couplings 105b, 105d of the pantographic linkage 105 are held in engagement with a push mechanism 102 at 0 its push plate 103. The push plate 103 moves into a position shown in solid line in Figure 1 on retraction of the linkage 105 and into a position shown in phantom 20 line on extension of the linkage 105. The frame 101 has a pair of vertical guide grooves 110, only one shown in Figure 2, in which a slider 111 is guidedly received.

The lower rear coupling 105c of the pantographic linkage 105 has a connecting pin 112 pivotally mounted adjacent to a bottom portion of the frame 101, while the upper rear coupling 105a has a connecting pin 113 pivotally connected to the slider 111. To the pin 112 -7- 7- is interconnected one end of each of a pair of arms 105g, only one shown, and to the pin 113 is interconnected one end of each of a pair of arms 105e, only one shown-, both arms being interconnected at a mid-portion at a pivot 106 in crossed relation to eachother. The arm 105g at the opposite end is interconnected to one end of each of a pair of arms 105h, only one shown, via a pivot 107, and the arm 105e is connected to one end of each of a pair of arms 105f, only one shown, via a pivot 108. The o^ 10 arms 105h, 105f are provided at their respective opposite ends with connecting pins 114 and 115, o respectively. Located in close proximity to the pin 114 is a pivotally movable connecting pin 116 to which is connected one end of a cylinder 117 provided at the 0000o 15 opposite end with a piston rod 118 interconnected via a apivot 109 to an arm 105i. The cylinder 117 is actuated to retract and extend the pantographic linkage 105.

The push plate 103 is provided therein with a pair of vertical guide grooves 120, only one shown, in which 20 two sliders 121, 122 are movably received. To the slider 121 is pivotally connected the pin 114, and to the slider 122 is pivotally connected the pin 115 so that the plate 103 is vertically n'ivable relative to the pantographic linkage 105.

As illustrated in Figures 4 and 5, the guide groove 120 is arranged to receive a stopper 124 for restricting downward movement of the push plate 103 and another stopper 125 for restricting upward movement of the plate 103, respectively, relative to the linkage 105. The sliders 121, 122 are positioned outwardly of the stoppers 124, 125 in the guide groove 120. With this construction, the slider 121 is brought into contact with the stopper 124 and the slider 122 with the stopper 125 when the pantographic linkage 105 is fully extended, as shown in Figure 4, so that the push plate 103 is held immovable in either direction. On full 040, I 0* 10 retraction of the linkage 105, the slider 122 is displaced upwardly as shown in Figure 5 so that the O plate 103 can freely ascend. In each instance the stopper 324 acts to arrest the plate 103 tending to move downwardly by its own gravity thereby preventing the .j°o 15 plate 103 from inadvertently descending beyond the lower S0"o limits shown in Fiaures 4 and A gripper mechanism 123 is fixedly mounted on a lower end of the push plate 103 of the push mechanism 102, as shown in Figure 2, for gripping the pallet P.

20 The gripper 123 integral with the plate 103 is vertically movable in response to retraction of the Spantographic linkage 105 so that the gripper is displaceable from a first position in which it is located close to a load-supporting surface 104a of the platen 104 to a second position in which it is remote from the surface 104a. The gripper 123 is made up of a first jaw 126 firmly secured to the push plate 103 at 9 its lower end by means of connectors 126a, 126b as better shown in Figure 3, a cylinder 127 fixed to the plate 103 via connectors 127a, 127b as better shown in Figure and a second jaw 129 vertically movably connected via connectors 129a, 129b to a piston rod 128 of the cylinder 127. The jaws 126, 129 serve to clamp therebetween the pallet P upon actuation of the cylinder 127.

.a o A presser mechanism 130 is mounted on a bottom 10 portion of the frame 101 so as to press the pallet P 0 against the platen 104. Included in the presser 130 is So" a pressing member 132 pivotally connected to the frame Q 00 a s 101 through a connecting pin 131. Designated at 134 is a cylinder pivotally connected to the frame 101 by a connecting pin 133. The pressing member 132 is secured 0o4 to the cylinder 134 at its piston rod 135 via a connecting pin 136. The pressing member 132 on 0 0 clockwise rotation in Figure 3 moves into a first position in which it presses the pallet P against the 20 platen 104 and on counterclockwise rotation moves into a second position in which it unclamps the pallet P and engages the first jaw 126 when the pantographic linkage retracts rearwardly, elevating the gripper mechanism 123 together with the push plate 103.

In handling the load L deposited on the sheet pallet P, the pantographic linkage 105 is extended to move the push plate 103 forwardly. This movement can be o.

10 effected substantially at constant speed on account of the cylinder 117 being located between the plate 103 and the pivot 109. At the foremost, fully extended location the plate 103 is restricted in its vertical movement on abutting engagement with the stoppers 124, 125. The pallet P is then clamped by the gripper mechanism 123, while the plate 103 begins to retract. In response to rearward movement of the plate 103, the pallet P with o the load L supported thereon is pulled onto the platen 10 surface 104a. In such instance the plate 103 is movable a o* upwardly because the distance between the two sliders 121, 122 is larger than that between the two stoppers 124, 125.

The cylinder 127 is thereafter actuated to raise 15 the second jaw 129 thereby unclamping the pallet P.

o Subsequent manipulation of the cylinder 134 causes the pressing member 132 to rotate into the second position f in which the member 132 comes into engagement with the first jaw 126 thereby elevating the gripper mechanism 123 and the cooperating plate 103 and resting the pallet P at one end on the platen 104.

Actuation of the cylinder 117 allows tie pressing member 123 to rotate into the first position in which the pallet P is pressed against the platen 104. The pantographic linkage 105 extends to allow for forward movement of the plate 103 so that the load alone is pushed out of the pallet and the pallet is recovered as 1: 11 unloaded.

In the push-pull assembly of the invention, the push plate 103 is arranged to move vertically with respect to the pantographic linkage 105. To recover the sheet pallet unloaded, the pressing member 132 is rotated into the second position so as to ascend the gripper mechanism 123 together with the plate 103. This arrangement is not requiste of elevating the linkage 105 Sand hence advantageous in that pallet recovery is 10 achieved with energy held to an absolute minimum and 0096 000o o with construction simplified and further in that the 0o cooperative action between the first and second jaws 126, 129 is effected independently of shifting the pressing member 132 to the second position. It is thus made possible to easily adjust the timing in which the 0 0 00o pallet P is unclamped from the gripper mechanism 123 and 0 t S the timing in which the pressing member 132 is displaced ii' into the second position to elevate the plate 103. The plate 103 can be restricted in its vertical movement when the pantographic linkage 105 is fully extended and can move upwardly when the linkage 105 is fully retracted. The plate 103 can therefore support the load L stablly in place upon extension of the linkage 105, and the pallet recovery is efficiently made on retraction of the linkage 105. Because the cylinder 117 is positioned forwardly of the pivot 109, the sight is clear forwardly of the plate 103 even when the linkage 12 105 is fully retracted, while the plate 103 can be forwardly and rearwardly moved at constant speed.

Certain modifications may be made in the structure specified above. For instance, a push plate may be mounted to a tip end of a pantographic linkage and provided with a vertically or rotatably movable gripper mechanism such that a pressing member is moved to displace a gripper mechanism without the push plate °r ,being displaced; that is, it is convenient to displace a gripper mechanism on rotation of a pressing member.

Turning to Figures 6 and 7, there is shown a platen section according to a second embodiment of the o <O invention in which it is releasably mounted in the above push-pull assembly.

The platen section of the invention comprises a *o0 pair of upper and lower engaging members 300, 301 located respectively on the right and left sides of the frame 101, only the right members being shown in Figure 6. The upper engaging member 300 has at its top front end an upwardly extending protrusion 300a, and the lower engaging member 301 has at its bottom front end a downwardly, extending protrusion 301a. To the engaging members 300, 301 is connected a platen unit 303 which includes a platen 104, a pressing member 132 and a cylinder 134.

The platen 104 includes a load-supporting surface 104a having a flat extension 104b and an upright portion 13 104c extending from one end of the extension 104b. At the lower end of the upright portion 104c is provided an engaging member 304 movable horizontally into engagement with the lower engaging member 301 by means of interconnection of the downward protrusion 301a of the member 301 with an upwardly extending protrusion 304a of the member 304. Disposed above the upright portion 104c is an engaging member 305 movable horizontally into oe engagement with the upper engaging member 300. The 10 member 305 has a downwardly extending protrusion 305a engageable with the upward protrusion 300a of the member o 300.

i 3 o o The engaging member 305 is provided centrally with a female threaded opening not shown for receptive engagement with a male screw 306 so as to prevent the ooo platen 104 against accidental sliding movement.

Designated at 307 is a female screw held in threaded 1 0 engagement with the male screw 306 to hold the latter in place.

The pressing member 132 is pivotally connected to the platen portion 104c by means of a pin 201 on a bracket 200 secured to a lower front surface of the portion 104c.

The cylinder 134 is pivotally connected to the platen portion 104c by means of a pin 203 on a bracket 202 secured to an upper front surface of the portion 104c. The cylinder 134 is pivotally connected at its I -14piston rod 135 to the pressing member 132 through a connecting pin 136.

Operation of the pressing member 132 and the cylinder 134 is similar to what has been described in connection with the first embodiment.

To detach the platen unit 303 from the push-pull assembly, the male screw 306 is loosened to move the platen 104 thereby disengaging the engaging members 300, 301 from the engaging members 305, 304, respectively.

S' 10 Just the opposite is done to assemble the platen unit.

0 oi With this construction, the platen 104, the 00 Spressing member 132 and the cylinder 134 are releasably o integral. Assembly and disassembly are rather simple, and maintenance is easy.

In the second embodiment the platen 104 of the platen unit 303 is mounted releasably on the frame 101 so as to attach and detach the platen unit 303. The 00' cylinder 134 may be releasably mounted on the frame 101.

Two pressing members 132 of a pair of laterally spaced platen units may also be integrally connected as by a suitable rod. A pressing member of a vertically movable type may also be used.

A

Claims (6)

1. A push-pull assembly for use on forklift trucks which comprises: a carriage mounted vertically movably on a mast of a forklift truck and provided at a lower end thereof with a platen having a surface for supporting thereon a sheet pallet and a load deposited on said pallet; 0o 0 retractable and extensible means comprising a rear coupling portion mounted on said carriage and a *POO 10 front coupling portion movable rearwardly and forwardly with respect to said rear coupling portion; face means connected to said front coupling portion of said retractable and extensible means and ooaoo comprising a face member supportive of said load and o o t 6 grip means movable between a first position in which it is close to said load-supporting surface of said platen and a second position in which it is remote from said load-supporting surface, said grip means capable of clamping said sheet pallet in said first position; and i 20 press means for pressing said sheet pallet against said lift means, said press means comprising means movable between said first and second positions and rotatable to press said sheet pallet against said carriage in said first position and rotatable to move said grip means into said second position, and means for selectively actuating said rotating means between said 16 first and second positions.

2. A push-pull assembly according to claim 1 wherein said face means comprises means for vertically movably connecting said face member to said front couplings of said retractable and extensible means, and means for mounting said grip means on said face member.

3. A push-pull assembly according to claim 2 wherein said face means comprises means for restricting Sdownward movement of said face member. 04:4 10

4. A push-pull assembly according to claim 3 wherein said face means comprises means for restricting I 4 o upward movement of said face member upon forward I o "extension of said front coupling portion of said retractable and extensible means and allowing said upward movement upon retraction of said front coupling portion of said retractable and extensible means.

A platen section adapted to be releasably '4o4 mounted on a push-pull assembly for use on forklift trucks, which comprises: 20 a frame mounted vertically movably on a mast of a forklift truck; a platen unit removably attached to said frame and comprising a platen having a load-supporting surface to support thereon a sheet pallet and a load carried on said pallet, and press member movable between a first position in which it is adjacent to said load- supporting surface of said platen and a second position between the first and second positions; and means for holding the platen unit in interengaged relation to the frame. 17 in which it is remote from said load-supporting surface, said press means capable of pressing said sheet pallet against said platen in said first position, said press means including actuating means for selectively moving said press member between said first and second positions; and means for holding said platen unit in interengaged relation to said frame.

6. A platen section according to claim 5 wherein 10 said holding means comprises means for releasably attaching said platen on to said frame, and said platen unit comprises means for mounting said press means and said actuating means on said platen. o o oof o 0 0000 0 0 CO 00 o Ob 000 o 00 0 0 00 OI Dated this 24th day of August 1990 NIPPON PETROCHEMICALS CO. LTD and YAMAKAWA ENGINEERING CO. LTD BY: Patent Attorneys for the Applicant F. B. RICE CO. L