JP3211801U - forklift - Google Patents

Abstract

A forklift that improves the efficiency of transportation work is provided. A forklift 10 supports a lift bracket 23 supported by a mast 13 so as to be movable up and down, a shaft 25 supported rotatably by the lift bracket and having a rotation axis L1 extending in a vertical direction, and a fork 11. And a fork bracket 26 that can pivot about the rotation axis of the shaft as the shaft rotates. Further, the forklift is interposed between the lift bracket 23 and the fork bracket 26, and expands and contracts as the fork bracket rotates, and oil flows to and from the hydraulic cylinder based on an external force applied to the fork. And a switching valve 30 that can be switched between a first switching state that allows oil flow in the hydraulic circuit and a second switching state that restricts oil flow. [Selection] Figure 2

Description

  The present invention relates to a forklift.

  Generally, forklifts, as disclosed in, for example, Patent Document 1, a lift bracket is supported by a mast standing on a front portion of a vehicle body so as to be movable up and down. The lift bracket is equipped with a fork for loading a load. The fork can be lifted and lowered together with the lift bracket by driving the lift cylinder. Further, the fork can be tilted back and forth together with the mast by driving the tilt cylinder.

JP 2009-57161 A

  By the way, in a forklift, since the lift bracket to which the fork is mounted is supported by the mast, the angle of the fork in the horizontal direction with respect to the traveling direction of the vehicle body does not change, and there is no degree of freedom of the fork. Therefore, for example, the angle when the fork is inserted into the pocket of the pallet (conveyed material) into which the fork is inserted depends on the traveling direction of the vehicle body. At this time, if the traveling direction of the vehicle body is tilted with respect to the pallet, it is necessary to change the traveling direction of the vehicle body or when the passage width is narrow so that the traveling direction of the vehicle body cannot be changed. Since it becomes difficult to insert the fork into the pocket of the pallet, the efficiency of the transportation work is deteriorated.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a forklift capable of improving the efficiency of transportation work.

  A forklift that solves the above-described problem is a fork that loads a transported object, a mast that is erected on the front of a vehicle body, a lift bracket that is supported by the mast so as to be movable up and down, and is rotatably supported by the lift bracket. Between the lift bracket and the fork bracket, a shaft extending in the vertical direction with a rotation axis, a fork bracket that supports the fork and is rotatable about the rotation axis of the shaft as the shaft rotates. And a hydraulic circuit that expands and contracts as the fork bracket pivots, a hydraulic circuit that moves oil back and forth based on an external force applied to the fork, and a flow of oil in the hydraulic circuit A first switching state to be permitted and a first switching state that regulates an oil flow in the hydraulic circuit. A switching valve capable of switching to the switching state, with a.

  According to this, the flow of oil in the hydraulic circuit is allowed by setting the switching valve to the first switching state, and the hydraulic circuit can move oil back and forth with respect to the hydraulic cylinder based on the external force applied to the fork. It becomes. Thereby, turning about the rotation axis of the shaft in the fork bracket is permitted by expansion and contraction of the hydraulic cylinder, and the fork can turn around the rotation axis of the shaft together with the fork bracket. Therefore, since the fork turns around the rotation axis of the shaft by the external force applied to the fork, the angle of the fork in the horizontal direction with respect to the traveling direction of the vehicle body changes, so the degree of freedom of the fork increases.

  In the state where the fork is loaded on the fork, when the switching valve is set to the second switching state, the flow of oil in the hydraulic circuit is restricted, the hydraulic cylinder is not expanded and contracted, and the shaft rotation axis of the fork bracket is centered. The turn is no longer performed. Therefore, since the fork does not turn around the rotation axis of the shaft in the state where the transported object is loaded on the fork, the fork is prevented from turning due to vibration during traveling of the vehicle body and is loaded on the fork. It can suppress that the conveyed material which falls is falling from a fork. As a result, it is possible to improve the efficiency of carrying work using a forklift.

  According to this device, the efficiency of carrying work can be improved.

A side view of a forklift in an embodiment. The partial top view of a forklift. The partial side view of a forklift. The schematic diagram which shows the positional relationship of a forklift and a conveyed product.

Hereinafter, an embodiment embodying a forklift will be described with reference to FIGS.
As shown in FIG. 1, the forklift 10 includes a pair of left and right forks 11 on which a transported article W1 is loaded. The transported object W1 is formed by loading a load W2 on a pallet P1, for example. The forklift 10 inserts the fork 11 into the pocket P2 of the pallet P1 loaded with the load W2 and picks up the pallet P1 to load the transported material W1 on the fork 11 and then loads the transported material W1 on the fork 11 in a predetermined state. After traveling to this place, the carrying work for placing the article W1 is performed.

  The forklift 10 includes a mast 13 erected on the front portion of the vehicle body 12. The mast 13 can be tilted back and forth by driving a tilt cylinder 14 connected to the mast 13. Further, the forklift 10 includes a drive wheel 15 (front wheel) provided at the front lower portion of the vehicle body 12 and a steering wheel 16 (rear wheel) provided at the rear lower portion of the vehicle body 12. The vehicle body 12 is provided with a traveling motor 17 that drives the drive wheels 15. Further, a battery 18 is mounted on the vehicle body 12. The traveling motor 17 is driven by electric power supplied from the battery 18. The forklift 10 travels when the driving wheels 15 are driven by the driving motor 17.

  As shown in FIG. 2, the mast 13 has a pair of left and right outer masts 19 and a pair of left and right inner masts 20 disposed inside the pair of outer masts 19. The pair of left and right outer masts 19 are connected to each other in parallel by an outer mast support 21. The pair of left and right inner masts 20 are connected in parallel to each other by an inner mast support 22. A lift bracket 23 is supported on the pair of left and right inner masts 20.

  The mast 13 has a pair of left and right lift cylinders 24. Piston rods 24 a of both lift cylinders 24 are connected to both ends of the inner mast support 22. The pair of left and right inner masts 20 moves up and down via the inner mast support 22 by the movement of both piston rods 24a in the vertical direction (vertical direction). Thereby, the lift bracket 23 moves up and down together with the pair of left and right inner masts 20. Therefore, the lift bracket 23 is supported by the mast 13 so as to be movable up and down.

  As shown in FIG. 3, the lift bracket 23 has a main body portion 23a supported by a pair of left and right inner masts 20 and a pair of upper and lower support portions 23b projecting on the opposite side of the mast 13 in the main body portion 23a. doing. The pair of upper and lower support portions 23b has a flat plate shape.

  A shaft 25 is rotatably supported between the pair of upper and lower support portions 23b. One of the pair of upper and lower support portions 23b rotatably supports one end portion of the shaft 25, and the other of the pair of upper and lower support portions 23b rotatably supports the other end portion of the shaft 25. Therefore, the shaft 25 is rotatably supported by the lift bracket 23. A rotation axis L1 of the shaft 25 extends in the vertical direction.

  As shown in FIGS. 2 and 3, the forklift 10 includes a fork bracket 26 that supports a pair of left and right forks 11. The pair of left and right forks 11 are attached to the fork bracket 26. The fork bracket 26 is disposed in front of the lift bracket 23 with a space in the front-rear direction of the vehicle body 12 with respect to the lift bracket 23.

  The fork bracket 26 is fixed to the outer peripheral surface of the shaft 25 via a fixing portion 27. The fixing portion 27 is, for example, a welding portion that fixes the outer peripheral surface of the shaft 25 and a portion of the fork bracket 26 on the lift bracket 23 side by welding. The shaft 25 is disposed between the lift bracket 23 and the fork bracket 26 in the front-rear direction of the vehicle body 12 and at the center in the left-right direction of the lift bracket 23 and the fork bracket 26. The fork bracket 26 can turn around the rotation axis L <b> 1 of the shaft 25 as the shaft 25 rotates.

  The fork 11 can be lifted and lowered together with the lift bracket 23 and the fork bracket 26 by driving a pair of left and right lift cylinders 24. Further, the fork 11 can tilt forward and backward together with the mast 13, the lift bracket 23 and the fork bracket 26 by driving the tilt cylinder 14.

  The forklift 10 includes a hydraulic cylinder 28 that is interposed between the lift bracket 23 and the fork bracket 26 in the longitudinal direction of the vehicle body 12 and that expands and contracts as the fork bracket 26 turns.

  Further, the forklift 10 has a hydraulic circuit 29 that moves oil back and forth with respect to the hydraulic cylinder 28 based on an external force applied to the fork 11, a first switching state that allows the oil flow in the hydraulic circuit 29, and the oil in the hydraulic circuit 29. And a switching valve 30 that can be switched to a second switching state that regulates the flow. The switching valve 30 is an electromagnetic valve provided in the hydraulic circuit 29. The switching between the first switching state and the second switching state in the switching valve 30 can be switched by, for example, a switch operation of a driver's switching switch. The hydraulic circuit 29 is provided with an accumulator 31.

  As shown in FIG. 3, the hydraulic circuit 29 includes a first flow path 29a that connects the hydraulic cylinder 28 and the switching valve 30, a second flow path 29b that connects the switching valve 30 and the accumulator 31, an accumulator 31, and a hydraulic cylinder. And a third flow path 29c that connects the second flow path 28 and the second flow path 29c.

  As shown in FIG. 2, when the switching valve 30 is in the first switching state, a force is applied to the fork 11, and for example, the fork bracket 26 is rotated by the shaft 25 and the arrow shown in FIG. When trying to turn about the rotation axis L1 of the shaft 25 in the direction of R1, the flow of oil in the hydraulic circuit 29 flows in the direction indicated by the arrow A1, for example. Then, the hydraulic cylinder 28 is extended by the oil flowing back and forth with respect to the hydraulic cylinder 28, and the fork bracket 26 is rotated about the rotation axis L1 of the shaft 25 in the direction of the arrow R1 shown in FIG. Turn. Therefore, the fork 11 turns in the direction of the arrow R1 shown in FIG. 2 about the rotation axis L1 of the shaft 25 by the external force applied to the fork 11, and the horizontal angle of the fork 11 with respect to the traveling direction X1 of the vehicle body 12 is Change.

  Further, when the switching valve 30 is in the first switching state, a force is applied to the fork 11, and for example, the fork bracket 26 rotates in the direction of the arrow R2 shown in FIG. When trying to turn around the rotation axis L1 of 25, the oil flow of the hydraulic circuit 29 flows in the direction indicated by the arrow A2, for example. Then, the hydraulic cylinder 28 is contracted by the oil flowing back and forth with respect to the hydraulic cylinder 28, and the fork bracket 26 is rotated about the rotation axis L1 of the shaft 25 in the direction of the arrow R2 shown in FIG. Turn. Accordingly, the fork 11 turns in the direction of the arrow R2 shown in FIG. 2 around the rotation axis L1 of the shaft 25 by the external force applied to the fork 11, and the horizontal angle of the fork 11 with respect to the traveling direction X1 of the vehicle body 12 is increased. Change.

The accumulator 31 has a function of adjusting the pressure in the hydraulic circuit 29.
Next, the operation of this embodiment will be described.
As shown in FIG. 4, when the traveling direction X1 of the vehicle body 12 is inclined with respect to the insertion direction Y1 of the pocket P2 of the pallet P1, if the fork 11 is forced to be inserted into the pocket P2 of the pallet P1, the fork 11 External force is applied to 11.

  At this time, by setting the switching valve 30 to the first switching state, the flow of oil in the hydraulic circuit 29 is allowed, and the hydraulic circuit 29 moves oil back and forth with respect to the hydraulic cylinder 28 based on the external force applied to the fork 11. It becomes possible. Thereby, turning about the rotation axis L1 of the shaft 25 in the fork bracket 26 is allowed by expansion and contraction of the hydraulic cylinder 28, and the fork 11 turns about the rotation axis L1 of the shaft 25 together with the fork bracket 26. Therefore, the fork 11 turns around the rotation axis L1 of the shaft 25 by the external force applied to the fork 11, and the horizontal angle of the fork 11 changes with respect to the traveling direction X1 of the vehicle body 12. This makes it possible to smoothly insert the fork 11 into the pocket P2 of the pallet P1 even in an environment where the width H1 of the passage T1 is such that the traveling direction X1 of the vehicle body 12 cannot be changed.

  Then, when the transported object W1 is loaded on the fork 11, when the switching valve 30 enters the second switching state, the flow of oil in the hydraulic circuit 29 is restricted, and the expansion and contraction of the hydraulic cylinder 28 is not performed. The turning about the rotation axis L1 of the shaft 25 is not performed. Therefore, in the state in which the transported object W1 is loaded on the fork 11, the fork 11 does not turn around the rotation axis L1 of the shaft 25, so that the fork 11 is prevented from turning due to vibration during travel of the vehicle body 12. Thus, the transported article W1 loaded on the fork 11 is prevented from falling from the fork 11.

In the above embodiment, the following effects can be obtained.
(1) Since the fork 11 turns around the rotation axis L1 of the shaft 25 due to an external force applied to the fork 11, the horizontal angle of the fork 11 changes with respect to the traveling direction X1 of the vehicle body 12. The degree of freedom increases. When the transported object W1 is loaded on the fork 11, the fork 11 does not turn around the rotation axis L1 of the shaft 25, so that the fork 11 is prevented from turning due to vibration during travel of the vehicle body 12. Thus, it is possible to suppress the transported article W1 loaded on the fork 11 from falling from the fork 11. As a result, it is possible to improve the efficiency of the transporting work of the transported material W1 using the forklift 10.

In addition, you may change the said embodiment as follows.
In the embodiment, switching between the first switching state and the second switching state in the switching valve 30 is, for example, control of the forklift 10 based on a detection signal of a sensor that detects whether or not the load W1 is loaded on the fork 11. The device may be switched automatically. For example, the control device switches the switching valve 30 to the first switching state when it is determined that the fork 11 is not loaded with the load W1 based on the detection signal of the sensor. Further, when the control device determines that the fork 11 is loaded with the transported material W1 based on the detection signal of the sensor, the control device switches the switching valve 30 to the second switching state.

  In the embodiment, the transported material W1 is not limited to a product in which the load W2 is loaded on the pallet P1 having the pocket P2, and may be a load having a hole into which the fork 11 is inserted, for example.

In the embodiment, the mast 13 may be a three-stage type including an inner mast, a middle mast, and an outer mast.
In the embodiment, the forklift 10 may be an engine type.

  W1 ... transported goods, 10 ... forklift, 11 ... fork, 12 ... vehicle body, 13 ... mast, 23 ... lift bracket, 25 ... shaft, 26 ... fork bracket, 28 ... hydraulic cylinder, 29 ... hydraulic circuit, 30 ... switching valve.

Claims (1)

A fork for loading the goods,
A mast erected at the front of the car body,
A lift bracket supported by the mast to be movable up and down;
A shaft that is rotatably supported by the lift bracket and whose rotation axis extends in the vertical direction;
A fork bracket that supports the fork and is rotatable about the rotation axis of the shaft as the shaft rotates;
A hydraulic cylinder interposed between the lift bracket and the fork bracket and extending and contracting as the fork bracket pivots;
A hydraulic circuit that moves oil back and forth with respect to the hydraulic cylinder based on an external force applied to the fork;
A forklift comprising a switching valve that can be switched between a first switching state that allows oil flow in the hydraulic circuit and a second switching state that restricts oil flow in the hydraulic circuit.