Mast buffer system for reach trucks

Abstract

This invention discloses a mast buffer system for a reach truck. The system includes an oil tank and an oil pump mounted on the truck body. The oil pump is connected to the oil tank and driven by a motor. The oil pump outlet is connected to a multi-way directional valve, which is connected to a reach cylinder. The return ports of the multi-way directional valve and the reach cylinder are connected to the oil tank. The system also includes a sensor switch and a solenoid valve. The sensor switch is mounted on the mast and electrically connected to the solenoid valve. By incorporating a buffer cylinder and a sensor switch on the mast, the system activates when the mast is raised, resulting in energy savings. It eliminates the need to trigger any switch to control the two-position four-way solenoid valve. Stopping the mast at any point within its full travel range reduces mast sway. Furthermore, the built-in spring in the buffer cylinder significantly enhances the damping effect on the mast.

Description

Technical Field

[0001] This invention relates to the field of forklift mast buffer equipment technology, specifically a mast buffer system for reach trucks. Background Technology

[0002] Chinese Patent Publication No. CN102515064B discloses a vibration damping system for an electric reach forklift mast. The system includes an oil tank with an inlet and return oil pipe connected to it. The inlet and return oil pipes are connected to a multi-way control valve, which is externally connected to a reach cylinder. A gear pump is installed in the inlet pipe, and an electric motor is externally connected to the gear pump. A two-position four-way solenoid valve is installed in the connecting pipe between the multi-way control valve and the reach cylinder. A limit switch is installed on the outside of the piston rod of the reach cylinder, and the limit switch is controlled by the two-position four-way solenoid valve. When the two-position four-way solenoid valve is energized, its two ports are connected. However, in actual use, the following drawbacks still exist: the vibration damping system can only be activated when the reach cylinder triggers the limit switch, and it cannot achieve vibration damping at any position during the mast's movement, resulting in limited vibration damping. Summary of the Invention

[0003] The purpose of this invention is to provide a mast buffer system for reach trucks to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] A mast buffer system for a reach truck includes an oil tank and an oil pump mounted on the truck body. The oil pump is connected to the oil tank and driven by a motor. The oil pump outlet is connected to a multi-way directional valve, which is connected to a reach cylinder. The return ports of the multi-way directional valve and the reach cylinder are connected to the oil tank. The system also includes a sensor switch and a solenoid valve. The sensor switch is mounted on the mast and electrically connected to the solenoid valve for detecting mast lifting. The solenoid valve is connected to the multi-way directional valve, the reach cylinder, and the buffer cylinder. Springs are installed in the rod-side chamber and the rodless chamber of the buffer cylinder.

[0006] Preferably, the solenoid valve is a two-position four-way solenoid valve.

[0007] Preferably, the buffer cylinder and the forward moving cylinder have the same cylinder diameter and rod diameter.

[0008] Compared with the prior art, the beneficial effects of the present invention are:

[0009] This invention incorporates a buffer cylinder and an inductive switch on the gantry. When the gantry is raised, the inductive switch is triggered, thereby activating the buffer system. This results in energy saving and reduced consumption. It eliminates the need to trigger any switch to control the two-position four-way solenoid valve. That is, stopping the movement at any point within the entire stroke of the gantry's forward and backward movement can reduce gantry sway. At the same time, the buffer cylinder has a built-in spring, which significantly improves the damping effect on the gantry. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of the hydraulic system of the present invention;

[0011] Figure 2 This is a schematic diagram of the forklift structure of the present invention;

[0012] Figure 3 A graph showing the swing amplitude of the top of the gantry during forward stacking operations without a buffer system.

[0013] Figure 4 This is a graph showing the swing amplitude of the top of the gantry during a forward stacking operation with an installed buffer system.

[0014] In the diagram: 1. Vehicle body, 2. Fuel tank, 3. Oil pump, 4. Motor, 5. Multi-way directional valve, 6. Forward moving cylinder, 7. Solenoid valve, 8. Mast, 9. Buffer cylinder, 10. Spring. Detailed Implementation

[0015] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] Please see Figure 1-4 The present invention provides a technical solution:

[0017] A mast buffer system for a reach truck includes an oil tank 2 and an oil pump 3 mounted on the truck body 1. The oil pump 3 is connected to the oil tank 2 and driven by a motor 4. The oil outlet of the oil pump 3 is connected to a multi-way directional valve 5. The multi-way directional valve 5 has an oil inlet (P port), an oil return port (T port), and an A port for mast lifting. The valve cores of the solenoid valves corresponding to A1 and B1 have the same function as those of the solenoid valve cores corresponding to A and B. The A1 and B1 ports are connected to other auxiliary hydraulic functions of the forklift. When the solenoids a1 and a2 in the multi-way directional valve 5 are not energized, the valve core is in the O position and is in a non-operating state, with no hydraulic oil output or return at ports A and B. When solenoid a1 is energized, the valve core is in the Y1 position. At this time, hydraulic oil with a certain pressure enters port A from port P, thereby pushing the reach cylinder 6. The corresponding hydraulic oil at port B flows back to port T and returns to the oil tank 2. When electromagnet a2 is energized, the valve core is in position Y2. At this time, hydraulic oil with a certain pressure enters port B from port P, which in turn pushes forward cylinder 6. The corresponding hydraulic oil at port A flows back to port T and returns to oil tank 2.

[0018] The multi-way directional valve 5 is connected to the forward-moving cylinder 6. One end of the forward-moving cylinder 6 is fixed to the forklift body 1, and the other end is fixed to the bottom of the mast 8. The return ports of the multi-way directional valve 5 and the forward-moving cylinder 6 are connected to the oil tank 2. It also includes an induction switch and a solenoid valve 7. The solenoid valve 7 is a two-position four-way solenoid valve. The induction switch is set on the mast 8 and electrically connected to the solenoid valve 7. It is used to detect the lifting of the mast 8. The solenoid valve 7 is connected to the multi-way directional valve 5, the forward-moving cylinder 6 and the buffer cylinder 9 respectively. The rod chamber and the rodless chamber of the buffer cylinder 9 are respectively equipped with springs 10. The cylinder diameter and rod diameter of the buffer cylinder 9 are the same as those of the forward-moving cylinder 6.

[0019] The mast 8 is equipped with a sensor switch to detect when the mast 8 is not extended. When the mast 8 is not extended, the sensor switch controls the two-position four-way solenoid valve to be in position a. At this time, the multi-way directional valve 5 performs forward or backward movement. The oil ports A of the multi-way directional valve 5, A1 and A2 of the two-position four-way solenoid valve, and A3 of the forward movement cylinder 6 are interconnected. The oil ports B of the multi-way directional valve 5, B1 and B2 of the two-position four-way solenoid valve, and B3 of the forward movement cylinder 6 are interconnected. When the cylinder rod of the forward movement cylinder 6 extends or retracts, the mast 8 moves forward or backward accordingly. When the mast 8 moves forward or backward, the multi-way directional valve 5 stops operating, and the forward movement cylinder 6 stops moving. At this time, the bottom of the mast 8 stops moving, while the top of the mast 8 swings back and forth due to inertia. Since the mast 8 is not extended, it does not affect the operation of the forklift.

[0020] Springs 10 are respectively installed in the rod chamber and the rodless chamber of the buffer cylinder 9. When oil enters one side of the oil chamber, it compresses the spring 10 in the other side of the oil chamber. The spring 10 generates an energy storage effect. When the hydraulic system stops providing pressure, the compressed spring 10 is released and pushes the piston in the buffer cylinder 9 to move. When the gantry 8 extends, the inductive switch controls the two-position four-way solenoid valve to be energized, and the valve core is in position b. When the multi-way directional valve 5 performs forward or backward movement, the oil ports A of the multi-way directional valve 5, A1, A2, and A4 of the two-position four-way solenoid valve, A3 of the forward movement cylinder 6, and A5 of the buffer cylinder 9 are interconnected. The oil ports B, B1, B2, and B4 of the multi-way directional valve 5, B3 of the forward movement cylinder 6, and B5 of the buffer cylinder 9 are interconnected. When the cylinder rod of the forward movement cylinder 6 extends or retracts, the gantry 8 moves forward or backward accordingly. At the same time, the oil inlet pressure of the buffer cylinder 9 is the same as that of the forward movement cylinder 6, and the return oil pressure is also the same. The oil inlet pressure of the buffer cylinder 9 is greater than that of the return oil chamber, and the spring 10 in the return oil chamber is compressed. When the gantry 8 moves forward or backward, the multi-way directional valve 5 stops operating, and ports A and B of the multi-way directional valve 5 disconnect. The two-position four-way solenoid valve, buffer cylinder 9, and forward cylinder 6 form a closed system. Within this system, because the multi-way directional valve 5 no longer provides pressure, the buffer cylinder 9 is released from its return chamber by the compression spring, pushing the piston rod of the buffer cylinder 9 to move, which in turn pushes the forward cylinder 6 to continue moving in the original direction. Simultaneously, it begins to compress the other side of the buffer cylinder 9's chamber. This repeated motion, with the springs 10 on both sides continuously being compressed and released, produces a continuous damping effect on the forward cylinder 6. When the gantry 8 moves forward or backward, the multi-way directional valve 5 stops operating, and the forward cylinder 6 stops moving accordingly. At this time, the bottom of the gantry 8 stops moving, while the top of the gantry 8 swings back and forth due to inertia. The direction of this swing is the same as the extension and retraction direction of the forward cylinder 6. The damping effect of the buffer cylinder 9 on the forward cylinder 6 counteracts the swing of the top of the gantry 8, resulting in a reduced swing amplitude and shorter swing time for the top of the gantry 8.

[0021] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A mast buffer system for a reach truck, comprising an oil tank (2) and an oil pump (3) mounted on a vehicle body (1), the oil pump (3) being connected to the oil tank (2) and driven by a motor (4), the oil outlet of the oil pump (3) being connected to a multi-way directional valve (5), the multi-way directional valve (5) being connected to a reach cylinder (6), and the return ports of the multi-way directional valve (5) and the reach cylinder (6) being connected to the oil tank (2), characterized in that: It also includes an induction switch and a solenoid valve (7). The induction switch is installed on the gantry (8) and is electrically connected to the solenoid valve (7) for detecting the lifting of the gantry (8). The solenoid valve (7) is connected to the multi-way reversing valve (5), the forward moving cylinder (6) and the buffer cylinder (9) respectively. The rod chamber and the rodless chamber of the buffer cylinder (9) are respectively provided with springs (10). The solenoid valve (7) is a two-position four-way solenoid valve; The buffer cylinder (9) has the same cylinder diameter and rod diameter as the forward moving cylinder (6); Among them, the multi-way directional valve (5) has oil inlet at port P and oil return at port T. Port A is the mast lifting oil circuit. The valve cores of the solenoid valves corresponding to A1 and B1 have the same function as the valve cores of the solenoid valves corresponding to A and B. Ports A1 and B1 are connected to other auxiliary hydraulic functions of the forklift. When the solenoids a1 and a2 in the multi-way directional valve (5) are not energized, the valve core is in position O and is in a non-operating state. There is no hydraulic oil output and return at ports A and B. When solenoid a1 is energized, the valve core is in position Y1. At this time, the pressurized hydraulic oil enters port A from port P and pushes the forward cylinder (6). The corresponding hydraulic oil at port B flows back to port T and returns to the oil tank (2). When solenoid a2 is energized, the valve core is in position Y2. At this time, the pressurized hydraulic oil enters port B from port P and pushes the forward cylinder (6). The corresponding hydraulic oil at port A flows back to port T and returns to the oil tank (2). When the mast (8) is not extended, the induction switch controls the two-position four-way solenoid valve to be in position a. At this time, the multi-way directional valve (5) performs forward or backward movement. The oil port A of the multi-way directional valve (5), the oil port A1 of the two-position four-way solenoid valve, the oil port A2 of the two-position four-way solenoid valve, and the oil port A3 of the forward movement cylinder (6) are connected to each other. The oil port B of the multi-way directional valve (5), the oil port B1 of the two-position four-way solenoid valve, the oil port B2 of the two-position four-way solenoid valve, and the oil port B3 of the forward movement cylinder (6) are connected to each other. The cylinder rod of the forward movement cylinder (6) extends or retracts, and the mast (8) moves forward or backward accordingly. When the mast (8) moves forward or backward, the multi-way directional valve (5) stops operating, and the forward movement cylinder (6) stops moving accordingly. At this time, the bottom of the mast (8) stops moving, while the top of the mast (8) swings back and forth due to inertia. Since the mast (8) is not extended, it does not affect the operation of the forklift. When the gantry (8) extends, the inductive switch controls the two-position four-way solenoid valve to be energized and the valve core is in position b. When the multi-way directional valve (5) performs forward or backward movement, the oil ports A of the multi-way directional valve (5), A1, A2, and A4 of the two-position four-way solenoid valve, A3 of the forward movement cylinder (6), and A5 of the buffer cylinder (9) are interconnected. The oil ports B of the multi-way directional valve (5), B1, B2, and B4 of the two-position four-way solenoid valve, B3 of the forward movement cylinder (6), and the buffer cylinder (9) are also interconnected. The oil ports B5 of the hydraulic cylinder (9) are connected to each other. The cylinder rod of the forward moving cylinder (6) extends or retracts, and the mast (8) moves forward or backward accordingly. At the same time, the oil inlet pressure of the buffer cylinder (9) is the same as that of the oil inlet pressure of the forward moving cylinder (6), and the oil return pressure is also the same. The oil inlet pressure of the buffer cylinder (9) is greater than that of the oil return chamber, and the spring (10) of the oil return chamber is compressed. When the mast (8) moves forward or backward, the multi-way reversing valve (5) stops operating, and the oil ports A and B of the multi-way reversing valve (5) are disconnected. The two-position four-way solenoid valve, the buffer cylinder (9), and the forward moving cylinder (6) form a closed system.

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