JP2508444Y2 - Load balancer - Google Patents

Description

[Detailed description of the device]

[0001]

[Industrial application] The present invention relates to a load balancer,
The present invention relates to a load balancer capable of transporting and moving a heavy load to a desired place with a slight force.

[0002]

2. Description of the Related Art When a heavy object such as an engine part is conveyed, a reaction force commensurate with the weight of the load is generated in advance, and a force corresponding to the load fluctuation caused by the operator's operation force is generated to lighten the heavy object. There is known a load balancer that can be transported and moved.

A conventional load balancer of this type is disclosed in Japanese Utility Model Laid-Open No. 61-197079. This is provided with an arm that can be freely moved by placing a heavy object,
The load transmitted through this arm is received by the pneumatic balance cylinder, and the entire load including the balance cylinder is received by the hydraulic weight sensing cylinder. The balance cylinder is connected to an air pressure source via a precision pressure reducing valve, and the weight sensing cylinder transmits the initial load due to the sensing load to the precision pressure reducing valve as pilot pressure.

According to such a load balancer, when a heavy object is first placed on the arm, a reaction force commensurate with the load is received by the weight sensing cylinder, and this is introduced into the precision pressure reducing valve as pilot pressure. The air pressure is introduced into the balance cylinder by opening and closing the precision pressure reducing valve to adjust the load reaction force commensurate with the operation fluctuations caused by performing the arm operation. is there.

[0005]

However, in the above-mentioned conventional load balancer, the working fluid in the balance cylinder is air, and when the stop mode is set because of its compressibility, the rod to which the load of the balance cylinder is applied is mechanically operated. Need to be restrained and fixed. A mechanical brake was usually used for this, and it was attached around the rod of the balance cylinder. Further, since the weight sensing cylinder needs to detect the load weight including the balance cylinder, it is necessary to make both cylinders a vertically integrated structure. For this reason, in the conventional load balancer, a mechanical brake must be provided in the cylinder part for the stop mode, and at the same time, the balance cylinder and the weight sensing cylinder are integrated, and the device must be enlarged. However, the degree of freedom in design was also limited, and there was a cost disadvantage.

The object of the present invention is to focus on the above-mentioned conventional problems, to simplify the structure of auxiliary equipment of the load balancer, to greatly improve the degree of freedom in design, and to realize a cost reduction. To provide a load balancer.

[0007]

In order to achieve the above object, a load balancer according to the present invention comprises a balance cylinder that receives a load as an oil pressure, an oil layer portion hydraulically connected to the balance cylinder, and a free surface of the oil layer portion. And a hydraulic / pneumatic cylinder in which an air layer portion in contact with is formed, and the air layer portion of this hydraulic / pneumatic cylinder is connected to an air pressure source via a precision pressure reducing valve, and the pilot pressure of the precision pressure reducing valve is connected. It is introduced through a hydraulic pipe connected to the balance cylinder, and an opening / closing valve is interposed between the hydraulic connecting pipe portion of the balance cylinder and the hydraulic / pneumatic cylinder and the pilot pressure introducing pipe.

[0008]

According to the above construction, the initial load is set through the hydraulic pipe extending from the balance cylinder to the precision pressure reducing valve. Then, the fluctuating force with respect to the set load is transmitted from the balance cylinder to the hydraulic / pneumatic cylinder by hydraulic pressure, and is detected as a pressure fluctuation in the air layer portion. This fluctuation is adjusted by the precision pressure reducing valve, pressurized air corresponding to the fluctuation is supplied from the pneumatic source to the hydraulic / pneumatic cylinder, the balance load is transmitted to the balance cylinder as hydraulic pressure, and the load is received by the hydraulic reaction force. Can be done. Then, by closing the on-off valve installed in the balance cylinder and the hydraulic pipe of the hydraulic / pneumatic cylinder pipe, the rod inserted in the balance cylinder is constrained and functions as a braking force. No need to equip. Further, since the balance cylinder and the hydraulic / pneumatic cylinder are connected by a hydraulic pipe, the routing of this pipe can be set freely, and both can be structurally arranged freely. Therefore, it is not necessary to provide a special weight sensing cylinder, and the structure can be simplified.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the load balancer according to the present invention will be described in detail below with reference to the drawings.

FIG. 2 shows an external configuration of the load balancer according to the embodiment. The load balancer includes a main arm 12 pivotally mounted on the carriage 10, and a lift cylinder 14 is attached between the main arm 12 and the carriage 10 so that the main arm 12 can be tilted. Further, a lift arm 16 is pivotally connected to the tip of the main arm 12, and the lift arm 16 can be bent with respect to the main arm 12 so as to be able to move up and down. A mounting table 20 on which a heavy object 18 is placed is attached to the tip of the lift arm 16. The mounting table 20 is designed to always maintain a horizontal plane regardless of the operation of the main arm 12 and the lift arm 16. Therefore, the main arm 12 and the lift arm 16 are constituted by a horizontal link mechanism.

In such a structure, the carriage 10 is equipped with a drive means 22 for controlling the lifting operation force of the lift arm 16 in order to convey the heavy load 18 in an unloaded state. A balance cylinder 24 forming a part is connected between the main arm 12 and the lift arm 16. The concrete structure of the driving means 22 is shown in FIG.

A piston 26 is slidably inserted into a balance cylinder 24 connected between the main arm 12 and the lift arm 16, and hydraulic oil is provided in a lower chamber defined by the piston 26. Is a hydraulic chamber 28 filled with. The other chamber is an atmosphere open chamber, and a rod 30 that receives the load from the heavy object 18 and the lift arm 16 as an axial force is inserted into the piston 26 to connect the piston 26 and the lift arm 16. are doing. Therefore, the balance cylinder 24 receives the load from the lift arm 16 side including the heavy object 18 as hydraulic pressure.

Further, a hydraulic / pneumatic cylinder 32 is installed in the bogie 10, and an oil layer portion 34 and air contacting the oil layer portion 34 on its free surface are filled by filling the inside thereof with a working oil having a volume of about 1/2. The layer portion 36 is formed. The oil layer portion 34 of the hydraulic / pneumatic cylinder 32 and the hydraulic chamber 28 of the balance cylinder 24 are connected by a hydraulic pipe 38 so that hydraulic oil can flow between the two cylinders 24 and 32. I have. An electromagnetic opening / closing valve 40 is provided in the middle of the hydraulic pipe 38 to shut off the flow. A compressed air source 44 is connected to the air / pneumatic cylinder 32 via an accurate pressure reducing valve 42 with respect to the air layer 36, and the operation of the precision pressure reducing valve 42 supplies and discharges compressed air to / from the hydraulic / pneumatic cylinder 32. Is performed.

By the way, the precision pressure reducing valve 42 compares the pressure of the air supplied from the compressed air source 44 to the hydraulic / pneumatic cylinder 32 with the pilot pressure, and supplies or discharges the compressed air according to the pressure fluctuation of the air layer portion 36. Make up. This pilot pressure is adapted to introduce the pressure in the hydraulic chamber 28 of the balance cylinder 24, so that the hydraulic pipe 46 is provided between the balance cylinder 24 and the pilot pressure introducing portion of the precision pressure reducing valve 42.
Is connected. An electromagnetic opening / closing valve 48 is interposed in the hydraulic pipe 46, and after the initial setting, the circuit is closed and the initial pressure is set as the pilot pressure in the precision pressure reducing valve 42.

The operation of the load balancer having such a configuration is as follows. The heavy object 18 to be conveyed is placed on the placing table 20 in a state where the open / close valve 40 connecting the balance cylinder 24 and the hydraulic / pneumatic cylinder 32 is shut off in advance. As a result, the initial load acts on the rod 30 of the balance cylinder 24 as an axial force, and a hydraulic pressure commensurate with this axial force is generated in the hydraulic chamber 28. This hydraulic pressure is transmitted to the precision pressure reducing valve 42 via a hydraulic pipe 46 and is set as a pilot pressure. After that, the opening / closing valve 48 is closed to fix the pilot pressure, and the opening / closing valve 40 connecting the cylinders 24 and 32 is opened. By this opening, the hydraulic pressure of the balance cylinder 24 is transmitted to the hydraulic layer 34 of the hydraulic / pneumatic cylinder 32, and compressed air is supplied from the compressed air source 44 so that the pressure of the air layer 36 is balanced with the initial load inside. You. When an operator lifts or pushes down the mounting table 20 from such a state, the fluctuation appears as a hydraulic pressure of the balance cylinder 24 as a pressure fluctuation of the air layer portion 36 in the hydraulic / pneumatic cylinder 32, and the fluctuation is compensated for. The precision decompression valve 42 operates, and the heavy object 18 can be moved easily to an arbitrary position.

In such a structure, particularly the cylinder 24,
By closing the on-off valve 40 provided in the hydraulic pipe 38 between 32, the piston 2 without the balance cylinder 24
6. As a result, the drive of the lift arm 16 can be stopped. Therefore, it is not necessary to employ a mechanical brake, and the equipment can be simplified.

Further, since the pilot pressure to the precision pressure reducing valve 42 directly introduces the hydraulic pressure generated in the balance cylinder 24, it is not necessary to attach a weight sensing cylinder to the balance cylinder 24, and the balance cylinder 24 portion can be made longer. It can be prevented. Moreover, the hydraulic / pneumatic cylinder 32 is mounted on the carriage 10.
Since it can be installed at any position of, there is an advantage that the degree of freedom in design is increased.

In the above embodiment, the presence or absence of the heavy load 18 is detected by a sensor such as a load cell installed on the mounting table 20.
Open / close valve 4 between cylinders when a drop of 8 etc. is detected
The logic may be incorporated so that the emergency shutoff operation of 0 is performed. With such a configuration, safety is improved in the case where the heavy object 18 falls during transportation.

[0019]

As described above, according to the load balancer of the present invention, a balance cylinder that receives a load as an oil pressure, an oil layer portion hydraulically connected to the balance cylinder, and an air layer contacting the oil layer portion with a free surface thereof are provided. And a hydraulic / pneumatic cylinder in which the air pressure portion of the hydraulic / pneumatic cylinder is connected to a pneumatic pressure source via a precision pressure reducing valve, and the pilot pressure of the precision pressure reducing valve is applied to the balance cylinder. Since it is introduced through connected hydraulic piping, an opening / closing valve is provided between the hydraulic connection piping section of the balance cylinder and the hydraulic / pneumatic cylinder and the pilot pressure introduction piping, thus simplifying the structure of auxiliary equipment of the load balancer. In addition to the above, it is possible to obtain the effect of significantly improving the degree of freedom in design and thus achieving cost reduction.

[Brief description of drawings]

FIG. 1 is a control circuit configuration of a load balancer according to an embodiment.

FIG. 2 is a perspective view showing an external configuration of a load balancer according to an embodiment.

[Explanation of symbols]

 10 dolly 12 main arm 16 lift arm 18 heavy goods 22 drive means 24 balance cylinder 28 hydraulic chamber 32 hydraulic / pneumatic cylinder 34 hydraulic layer section 36 air layer section 38, 46 hydraulic piping 40, 48 opening / closing valve 42 precision reducing valve 44 compressed air source

Claims (1)

(57) [Scope of utility model registration request] 1. A balance cylinder that receives a load as an oil pressure, and an oil-pneumatic cylinder in which an oil layer portion hydraulically connected to the load cylinder and an air layer portion that is in contact with the oil layer portion at its free surface are formed. The air layer portion of the pneumatic cylinder is connected to an air pressure source via a precision pressure reducing valve, and the pilot pressure of the precision pressure reducing valve is introduced through a hydraulic pipe connected to the balance cylinder. A load balancer characterized in that an opening / closing valve is provided between the hydraulic connection piping of the pneumatic cylinder and the pilot pressure introducing piping.