JPH08113145A - Low lift - Google Patents

Abstract

PURPOSE: To improve the inserting workability of a fork to a pallet by providing an energizing means to pull a push rod to a lift arm side after an auxiliary wheel is grounded, and to make a road wheel fall to the storing position inside the fork so as to float up from the road surface. CONSTITUTION: When an auxiliary wheel 9 is grounded, the contructing operation of a cylinder device 2 contructed by the weight of a board 5 and a fork 6 is eliminated, but a push rod 8 is energized in the direction of a lift arm 4 by a coil spring S1, the lift arm 4 is rotated further by the push rod 8, so as to contruct the cylinder device 2, and the board 5 and the fork 6 are inclined a little to a driver 1 side by making the auxiliary wheel 9 as the fulclum. And the road wheel 7 is stored inside the fork 6 while lifting up the tip of the fork 6, so as to float up the road wheel 7 from the road surface. Consequently, the road wheel 7 does not interfere with the board at the road surface side, and the fork 6 can be inserted smoothly to a pallet.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low lift for carrying a load placed on a pallet, and more particularly to a low lift for lifting a pallet using a single-acting cylinder device.

[0002]

2. Description of the Related Art A low lift is used for carrying work in factories and warehouses, for loading cargo on pallets and carrying the pallets together. As shown in FIG. 5, a low lift generally includes a drive unit 1 including a single-acting cylinder device 2 and a drive wheel 3, and a base unit 5 to which a pair of left and right forks 6 inserted into a pallet or the like is fixed. , And has a basic structure connected through a pair of left and right lift arms 4. At the tip of the fork 6, a road wheel 7 is attached to a support arm 7
It is mounted so as to be capable of undulating via 1 and is connected to the lift arm 4 by a push rod 8. Therefore, due to the expansion and contraction of the cylinder device 2, the base portion 5
Moves up and down together with the fork 6, the lift arm 4 rotates, and the road wheel 7 undulates via the push rod 8.

In the low lift described above, when the fork 6 is inserted into the pallet, when the pallet is transported, and when the pallet is lowered, the road wheel 7 is grounded on the road surface and when the fork 6 is inserted into the pallet. If the pallet is a double-sided pallet, when the road wheel 7 gets over the roadside board, the pallet escapes due to the pressing force, and the workability of inserting the fork 6 is poor.

On the other hand, as shown in FIG. 6, an auxiliary wheel 9 is provided in the vicinity of the base end of the fork 6 of the base part 5, which floats when the base part 5 rises and grounds during the lowering operation. , There is a structure in which the fork 6 is held at a predetermined floating position (Act No. 1-16695). This low lift is based on the base 5
In the descending operation of, even after the auxiliary wheels 9 are in contact with the ground and the lowering of the base portion 5 is completed, the cylinder device 2 is contracted, the load wheel 7 is laid down to the retracted position and floated from the road surface, and the fork 6 is moved to the pallet P. insert. Therefore, a double-acting cylinder device that is forcibly contracted after the auxiliary wheel 9 is grounded is required, which is disadvantageous in terms of cost and complicated to operate.

[0005]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to realize a low lift with a good workability of inserting a fork into a pallet by using a single-acting cylinder device which is advantageous in cost and easy to operate. It was made.

[0006]

According to the present invention, as shown in FIG. 1, a drive unit 1 having a single-acting cylinder device 2 and a drive wheel 3 is connected to the drive unit 1 via a lift arm 4. A base portion 5 that moves up and down as the cylinder device 2 expands and contracts; a fork 6 that extends forward from the base portion 5 and is inserted into a pallet or the like; In a low lift equipped with a load wheel 7 which is movably attached and is connected to the lift arm 4 via a push rod 8 so as to raise and lower the fork 6 by the rotation of the lift arm 4 as the cylinder device 2 moves up and down, The base portion 5 is provided with an auxiliary wheel 9 near the base end portion of the fork 6 that floats above the road surface when the base portion 5 rises and grounds while the base portion 5 is descending.
Further, after the grounding of the auxiliary wheel 9, the push rod 8 is pulled to the lift arm 4 side, and the biasing means is provided to make the road wheel 7 fall down to the storage position inside the fork 6 and float above the road surface.

As the urging means, as shown in FIGS. 1 and 2, a coil spring S1 having one end locked to the push rod 8 and the other end locked to the fork 6 at the lift arm 4 side is provided, A pulling force is applied to the push rod 8.

As the urging means, a torsion spring S2 is provided around the support shaft 41 of the lift arm 4 as shown in FIG. 3, and a rotational force is urged to the lift arm 4 to move the push rod 8 into the lift arm 4. Give a pulling force to the side.

As the urging means, a coil spring S3 having one end fixed to the piston rod 21 of the cylinder device 2 and the other end fixed to the cylinder 22 side is provided as shown in FIG. A force is applied to rotate the lift arm 4 to give a pulling force to pull the push rod 8 toward the lift arm 4.

[0010]

When the base 5 is lowered, the auxiliary wheel 9 is grounded before the cylinder device 2 reaches the bottom dead center. At this point, the road wheel 7 is still in contact with the ground, but the biasing means S1,
The lift arm 4 is rotated by S2 or S3, and the rotation of the lift arm 4 causes the cylinder unit 2 to contract to the bottom dead center while the base 5 inclines with the auxiliary wheel 9 as a fulcrum. When the push rod 8 is pulled toward the lift arm 4, the road wheel 7 further falls and floats above the road surface, and the fork 6 is inserted into the pallet without resistance.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the low lift includes a drive unit 1 and a base unit 5 connected to the drive unit 1 by a lift arm 4.
And a fork 6 extending forward from the lower end of the base 5 and inserted into the pallet. The drive unit 1 includes a cylinder device 2, a drive wheel 3, and an operation handle H. The cylinder device 2 is a single-acting cylinder device that is expanded by fluid pressure and contracts by the load applied to the piston rod 21, and the base end of the cylinder 22 is supported by the drive wheel 3, and the tip of the piston rod 21 is the base part. 5 is connected to a protrusion 51 at the rear of the upper end.

Inside the base 5, a control device for controlling the cylinder device 2 and the drive wheel 3, a battery and the like are housed. The base portion 5 has a lower portion formed by a pair of left and right lift arms 4 for supporting the drive wheel 3.
It is connected to 1. The lift arm 4 is substantially L-shaped, and one end of the lift arm 4 is rotatably supported by the support shaft 32 of the support 31, and the support shaft 41 provided in the bent portion of the L-shape is supported by the base 5. .

On the left and right sides of the lower end of the base 5, there are provided forks 6 extending forward and having a groove-shaped cross section open downward. A road wheel 7 is rotatably provided on a lower surface of the tip of the fork 6 by a support shaft 61 via a support arm 71. A push rod 8 is provided along the lower surface of the fork 6 along the same. The shaft 82 provided at one end is attached to the support arm 7
1 and the other end is connected to the other end of the lift arm 4. Therefore, when the lift arm 4 rotates, the support arm 71 rotates about the support shaft 61, and the road wheel 7 undulates with respect to the fork 6.

Auxiliary wheels 9 are provided at the lower left and right sides near the base end of the fork 6 of the base 5. The auxiliary wheel 9 is attached to a bracket 52 protruding from the base 5 so as to be adjustable in vertical position via an adjusting screw shaft 91 and a nut 92. As shown in FIG. 1 (A), the auxiliary wheel 9 floats up from the road surface when the fork 6 rises.
As shown in (B), the height position of the fork 6 is determined so as to contact the road surface when the fork 6 descends.

On the other hand, inside the pair of left and right forks 6,
A coil spring S1 for urging the push rod 8 toward the lift arm 4 is provided. As shown in FIG. 2, a pair of coil springs S1 are provided on both sides of the push rod 8, one end of which is locked to a bracket 81 fixed to the tip of the push rod 8, and the other end of which is lifted more than the bracket 81. It is locked to a bracket 62 fixed to the fork 6 on the arm 4 side.

In the above low lift, the base 5 is raised by extending the cylinder device 2.
Therefore, the support shaft 41 of the lift arm 4 is pulled up, and the lift arm 4 rotates upward about the support shaft 32. By this rotation, the push rod 8 is pushed out toward the tip of the fork 6, and the support arm 71 of the road wheel 7 is rotated downward about the support shaft 61 to erect the load wheel 7, whereby the base portion 5 And the fork 6 is raised (FIG. 1 (A)).

Next, when the pressure valve (not shown) of the cylinder device 2 is opened to lower the fork 6, the cylinder device 2 contracts due to the weight of the base 5 and the fork 6, and the base 5 descends. . Therefore, the support shaft 41 of the lift arm 4 is pulled down, and the lift arm 4 rotates downward about the support shaft 32. Then, the push rod 8 is pulled to the lift arm 4 side, the support arm 71 rotates upward about the support shaft 61, and the road wheel 7 is tilted to lower the base portion 5.
And the fork 6 is lowered and the auxiliary wheel 9 is grounded (FIG. 1 (B)).

When the auxiliary wheel 9 comes into contact with the ground, the contracting operation of the cylinder device 2 which contracts due to the weight of the base 5 and the fork 6 disappears, but the push rod 8 is urged toward the lift arm 4 by the coil spring S1 and pushed. The lift arm 4 is further rotated by the rod 8 to contract the cylinder device 2, and the base 5 and the fork 6 are slightly tilted toward the drive unit 1 with the auxiliary wheel 9 as a fulcrum. Then, while lifting the tip of the fork 6, the road wheel 7
Is stored inside the fork 6, and the road wheel 7 floats above the road surface (FIG. 1 (C)).

Since the low lift of this embodiment operates as described above, if the fork 6 is lifted from the road surface and the fork 6 is inserted into the pallet while the fork 6 is lifted as shown in FIG. 1 (C), The fork 6 is smoothly inserted into the pallet without the road wheel 7 interfering with the roadside board of the pallet. Then, as shown in FIG. 1 (A), the pallet loaded with the loads is lifted by the extension of the cylinder device 2 and the standing of the load wheel 7, and by operating the handle H, the drive wheel 3 and the load wheel 7 are rotated and transported. To be done. After transporting to a predetermined place, the fluid pressure of the cylinder device is released to lower the base part 5 and the fork 6, and
As shown in (B), the auxiliary wheel 9 comes into contact with the ground, and the action of the coil spring S1 brings about the state shown in FIG. 1 (C), so that the fork 6 can be smoothly pulled out from the pallet.

FIG. 3 shows an essential part of a second embodiment of the present invention, in which a support shaft 41 for supporting the lift arm 4 on the base 5 is provided.
Around it, a torsion spring S2 for urging a rotational force on the support shaft 41 is provided. The support shaft 41 is pierced and fixed to the bent portion of the arm 4 so as to extend over the left and right lift arms 4 (only one of which is shown in the figure), and both ends are rotatably supported by the base 5. There is. The torsion spring S2 provided around the support shaft 41 has one end locked to the base portion 5 and the other end locked to the support shaft 41, and biases the support shaft 41 in the direction of arrow A.

When the base 5 and the fork 6 are lowered, after the auxiliary wheels 9 are grounded, the lift arm 4 is rotated by the rotational force of the support shaft 41 to contract the cylinder device 2 and the auxiliary wheels 9 are rotated.
With the fulcrum as a fulcrum, the base 5 and the fork 6 are slightly tilted toward the drive unit 1. As a result, the push rod 8 connected to the tip of the lift arm 4 is pulled, and the road wheel 7 is stored in the fork 6 and floats above the road surface. Therefore, the same effect as that of the previous embodiment is produced. That is, the torsion spring S2 has the same function as the coil spring S1 provided on the fork 6 in the previous embodiment.

FIG. 4 shows an essential part of a third embodiment of the present invention. A coil spring for urging the cylinder device 2 in the contracting direction is provided between the cylinder 22 of the cylinder device 2 and the piston rod 21. S3 is provided. The coil springs S3 are provided in a pair on the left and right sides of the cylinder device 2. One end of the coil spring S3 is locked to the protruding portion 51 of the base portion 5 to which the piston rod 21 is connected, and the other end of the coil spring S3 is protruded from the cylinder 22. It is locked to a bracket 221 that connects the operation handle H.

When the base 5 and the fork 6 are lowered, the coil spring S3 continues the contracting action of the cylinder device 2 after the auxiliary wheel 9 is grounded, and the base 5 and the fork 6 are supported by the auxiliary wheel 9 as a fulcrum. It is slightly tilted toward the drive unit 1 side. As a result, the lift arm 4 rotates downward, the push rod 8 connected to the tip is pulled, and the road wheel 7 is stored in the fork 6 and floats from the road surface.
Therefore, the same effect as that of the previous embodiment is produced. That is, the coil spring S3 has the same function as the coil spring S1 provided on the fork 6 in the first embodiment.

[0024]

INDUSTRIAL APPLICABILITY The present invention, in a low lift for raising a fork by using a single-acting cylinder device, automatically inserts the fork into the pallet and removes the fork from the pallet after carrying a load without any special operation. Since the fork is located at the height of insertion into the pallet and the road wheel at the tip of the fork is floated above the road surface, the workability of carrying the load is greatly improved.

[Brief description of drawings]

1 (A) is a side view of a low lift according to the present invention when a fork is raised, and FIG. 1 (B) is a side view showing a state where auxiliary wheels are grounded while the low lift of FIG. 1 (A) is being lowered. FIG. 1C is a side view showing the low lift road wheel of FIG.

2 (A) is an enlarged perspective view of an essential part showing a biasing means of the present invention, and FIG. 2 (B) is a sectional view taken along a line IIB-IIB in FIG. 2 (A).

FIG. 3 is an enlarged perspective view of essential parts showing another urging means of the present invention.

FIG. 4 is an enlarged perspective view of essential parts showing still another urging means of the present invention.

FIG. 5 is a side view showing a conventional low lift.

FIG. 6 is a side view showing a low lift provided with a conventional auxiliary wheel.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Drive part 2 Single-acting cylinder device 3 Drive wheel 4 Lift arm 5 Base part 6 Fork 7 Road wheel 71 Support arm 8 Push rod 9 Auxiliary wheel P Pallet S1, S3 Coil spring (biasing means) S2 Torsion spring (with Means)

Claims (4)

[Claims] 1. A drive unit including a single-acting cylinder device and a drive wheel, a base unit connected to the drive unit via a lift arm, and a base unit that moves up and down as the cylinder device expands and contracts, and a base unit. A fork extending forward from the fork to be inserted into a pallet or the like, and the lift arm attached to the tip of the fork so as to be able to rise and fall via a support arm and connected to the lift arm via a push rod as the cylinder device moves up and down. In a low lift equipped with a road wheel that lifts and lowers the fork by rotating the base, the base part floats above the road surface near the base end of the fork when the base part rises, and touches the ground while the base part is descending. Auxiliary wheels are installed, and after the auxiliary wheels have touched down, pull the push rod toward the lift arm to collapse the road wheel to the stowed position inside the fork. A low lift characterized in that it is provided with a biasing means that allows it to float above the road surface. 2. A coil spring, one end of which is locked to a push rod and the other end of which is locked to a fork at a position on the lift arm side, is provided as the biasing means, and a pulling force is biased to the push rod. The low lift described in 1. 3. The low lift according to claim 1, wherein a torsion spring is provided around the support shaft of the lift arm as the urging means, and the push rod is pulled toward the lift arm by urging a rotational force on the lift arm. 4. A coil spring having one end fixed to a piston rod of a cylinder device and the other end fixed to the cylinder side is provided as the urging means, and a contracting force is urged to the cylinder device to rotate the lift arm. The low lift according to claim 1, wherein at least the push rod is pulled toward the lift arm.