JPH0625520Y2 - Fall prevention device for cargo handling equipment - Google Patents

Description

[Detailed Description of the Invention] "Industrial field of application" The present invention is, for example, to prevent a cargo handling machine from falling by elevating a cargo bed supported by an X-link to the ground surface or an appropriate height to load and unload cargo onto a truck cargo bed or the like. Regarding the device.

"Prior Art" Conventionally, there is a technique in which a loading platform supported via a pair of left and right link mechanisms is moved up and down by a pair of hydraulic cylinders, and the hydraulic cylinders are connected to a hydraulic drive unit that drives the hydraulic cylinders via hydraulic hoses. there were.

[Problems to be Solved by the Invention] In the above-mentioned conventional technology, there is a risk that the bed supported by the hydraulic cylinder may suddenly descend due to damage or detachment of the hydraulic hose.

In addition, a valve was also developed to detect pressure oil discharged from the hydraulic cylinder by cutting the hydraulic hose and prevent the pressure oil from being discharged from the hydraulic cylinder. In a case where a hydraulic cylinder is mounted compactly like a working machine, there is a structural problem that a conventional valve installation space cannot be easily secured around the hydraulic cylinder.

"Means for Solving Problems" However, according to the present invention, while the primary side port connected to the hydraulic pump and the oil tank and the secondary side port connected to the hydraulic cylinder are provided substantially parallel to the valve body, A control oil passage of the valve body for controlling the communication between the primary side and the secondary side is provided at each port in an orthogonal manner, and the control oil passage has an opening on one end side closed by a plug to be inside the valve chamber. The ball valve to be installed, the valve seat that abuts the ball valve to shut off each port by the return pressure oil from the hydraulic cylinder, and the valve end that is attached to the opening on the other end side of the control oil passage via the fixing bolt A pressure adjusting bolt for displacing the spool and a return flow spring interposed between the ball valve and the spool are provided, and the plug, ball valve, spring, spool, and pressure adjusting bolt are provided on the valve body in a substantially straight line. It is characterized by that.

"Operation" Therefore, by incorporating a ball valve in the valve body extremely compactly, it is possible to obtain a fall prevention valve with a high performance and a compact external structure that can be easily and safely installed around the hydraulic cylinder of a cargo handling machine. Especially, in this case, it is possible to easily take out and install the ball valve and the pressurizing adjusting bolt separately, and it is convenient for parts replacement and maintenance inspection, and stable performance can be easily maintained. However, it is possible to reduce the number of parts and the number of processing steps to improve the economical efficiency.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings. First
FIG. 2 is a hydraulic circuit diagram, FIG. 2 is a side view of a cargo handling machine, FIG. 3 is a front view of the same, and FIG. 4 is a plan view of the same, and a base having movable wheels (1) ... (2) and a flat loading platform (4) having a foldable ramp (3) (3), fixed fulcrum (5)
(6) and movable fulcrum (7) (8) through the base (2) and the loading platform (4)
A pair of left and right X-shaped links (9) and (10) are connected to the base, and the base can be moved up and down to the ground surface or an appropriate height via the X-shaped links (9) and (10).
(2) The platform (4) is mounted on the platform (2), and a pair of left and right hydraulic cylinders (11) (11) for raising and lowering the platform (4) are provided on the base (2), and the piston (12) of the cylinder (11) is installed. ) The tip is connected to one X-shaped link (10) through the support shaft (13), and the piston (1
2) is moved forward and backward to move the loading platform (4) up and down.

Also, a hydraulic drive unit having wheels (14) (14) for movement
As shown in FIG. 2, an operating box (18) having an ascending switch (16) and a descending switch (17) and a power plug (19) for three-phase alternating current are provided with a conductive wire (20). It is connected to the unit (15) via the (21), and as shown in FIG. 1, the electric motor (22), the hydraulic pump (23), and the hydraulic switching electromagnetic valve (2
4) etc. are internally provided in the unit (15).

Then, the fall prevention valve (2) that is connected and fixed to each of the single-acting hydraulic cylinders (11) and (11) via a hydraulic joint (25).
6), the valve (26) is fixed to the cylinder (11) on one side, and the valve (26) is connected to the secondary side of the electromagnetic valve (24) via a hydraulic hose (27). To connect,
By operating the raising switch (16), the electromagnetic valve (24) is switched to the raising side, the piston (12) of the hydraulic cylinder (11) is advanced to raise the platform (4), while the lowering switch (1
7) By operation, the electromagnetic valve (24) is switched to the lower side, the piston (12) of the hydraulic cylinder (11) is retracted, and the platform (4) is lowered.

Further, as shown in FIG. 1, the hydraulic pump (23) or the oil tank (2
8) via the solenoid valve (24) and hydraulic hose (27) to connect to the primary side port (29) and the hydraulic cylinder (11) via the hydraulic joint (25) to connect and fix the secondary side port (30). ) And the valve body (31) of the fall prevention valve (26), and a plug (33) to the valve chamber (32) of the valve body (31) for controlling the communication of the ports (29) and (30). ), The ball valve (34) is installed inside, and the ball valve (34) is contacted so that the return pressure oil from the hydraulic cylinder (11) shuts off the ports (29) and (30). A valve seat (35) is formed in the valve chamber (32).

Further, the ball valve (34) is opened to open each port (2
9) Return spring (36) for communicating (30), pressure adjustment bolt (39) attached to the valve body (31) through the fixing bolt (37) and lock nut (38), and the pressure adjustment Bolt (39)
And a spool (40) for displacing the screw (37) into and out of the fixing bolt (37), the spool (40) is used as a spring seat to abut one end side of the spring (36), and the other side of the spring (36). The end side is brought into contact with the ball valve (34), the spool (40) is brought into contact with the tip of the pressure adjusting bolt (39), and the spool (40) is displaced by the pressure adjusting bolt (39). A spring (36) on the valve body (31). Then, when the return pressure oil from the hydraulic cylinder (11) has a small hydraulic pressure,
The ball valve (34) is kept open by the spring (36), and the return pressure oil is returned to the oil tank (28) while the hydraulic hose
When the return pressure oil from the hydraulic cylinder (11) is large due to damage and disconnection of (27), etc., the return pressure oil causes the ball valve (34)
Close the spring (36) against the springs (36),
Is shut off by the ball valve (34) and the lowering operation of the hydraulic cylinder (11) is stopped to prevent the loading platform (4) from falling.

In addition, the plug (33), ball valve (34), pressurization adjusting bolt
(39), the spool (40), etc. are provided in a substantially straight line, and the ball valve (34), the spool (40), etc. are arranged in the middle, and the plug (33) and the pressure adjusting bolt (39) are arranged. They are arranged facing each other.

Further, as shown in FIGS. 5 and 6, the valve chamber (3
Spring head to be inserted into 2) and abut against valve seat (35)
(41) and a speed adjusting spring (42) having a smaller spring force than the return spring (36), and the return passage (4) in the axial direction of the spring head (41).
3) is formed, and by opening and closing the plug (33), the ball valve (34) shown in Fig. 1 is taken out, and the spring head (41) and spring (42) are mounted as shown in Fig. 6 and then lowered. It constitutes the speed control valve (44). The hydraulic cylinder (11)
(11) is connected in parallel to the hydraulic joint (25) by a hydraulic hose (25).

Then, when the hydraulic cylinder (11) descends with no load, the spring (36) separates the spring head (41) from the valve seat (35), and returns the return oil from the hydraulic cylinder (11) to the spring head (41). Oil tank through the gap between the valve and the valve seat (35)
Return to (28) and lower the hydraulic cylinder (11) at the set speed.When the load on the hydraulic cylinder (11) is large, the return pressure oil from the hydraulic cylinder (11) resists the spring (36). Contact the spring head (41) with the valve seat (35) and return the return pressure oil from the hydraulic cylinder (11) to the oil tank (28) through the return passage (43) of the spring head (41). The hydraulic cylinder (11) is moved down at a set speed, and the hydraulic cylinder (11) is moved down at a substantially constant speed regardless of the size of the load. Thus, ball valve (34)
By replacing the spring head (41) with the valve body (31) and the like, the fall prevention valve (26) or the descending speed adjusting valve (44) can be configured.

"Effects of the Invention" As is apparent from the above-described embodiments, the present invention has a hydraulic pump (2
3) and the primary side port (29) connected to the oil tank (28),
Connect the secondary port (30) connected to the hydraulic cylinder (11),
A valve body (3) that is provided substantially parallel to the valve body (31) and that controls communication between the primary side and secondary side ports (29) (30).
The control oil passage of 1) is provided orthogonally to each port (29) (30), and the control oil passage has a ball (3) provided inside the valve chamber (32) with an opening on one end side closed by a plug (33). Valve (34) and hydraulic cylinder (11)
The valve seat (35) that abuts the ball valve (34) to shut off each port (29) (30) by the return pressure oil from the valve seat and the fixing bolt (37) at the other end opening of the control oil passage. Pressure adjusting bolt (39) for displacing the spool (40) on the inner end side and the return spring provided between the ball valve (34) and the spool (40).
(36) with these plugs (33), ball valves (34), springs (36), spools (40), and pressure adjustment bolts (39) provided on the valve body (31) in a substantially straight line And the valve body
A ball valve (34), etc. is extremely compactly installed in (31) to achieve high performance and a compact outer shape that can be easily and safely installed around the hydraulic cylinder (11) of the cargo handling machine ( In particular, in this case, the ball valve (34) and the pressurizing adjustment bolt (39) can be easily taken out and installed separately from each other, which is convenient for parts replacement and maintenance inspection. As a result, stable performance can be easily maintained, and the number of parts and processing man-hours can be reduced to improve economic efficiency.

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram showing an embodiment of the present invention, FIG. 2 is a side view of a cargo handling machine, FIG. 3 is a front view thereof, FIG. 4 is a plan view thereof, and FIGS. FIG. 14 is an explanatory diagram of an application example. (11) …… hydraulic cylinder (23) …… hydraulic pump (28) …… oil tank (29) …… primary side port (30) …… secondary side port (31) …… valve body (32) …… Valve chamber (34) …… Ball valve (36) …… Return spring (39) …… Pressure adjusting bolt (40) …… Spool

Claims (1)

[Scope of utility model registration request] 1. A valve body (31) comprising a primary port (29) connected to a hydraulic pump (23) and an oil tank (28) and a secondary port (30) connected to a hydraulic cylinder (11). , And the control oil passages of the valve body (31) for controlling communication between the primary side and secondary side ports (29) and (30) are provided in parallel with each port (29).
A ball valve that is provided orthogonally to (30), and the control oil passage is internally provided in the inner valve chamber (32) by closing the one end side opening with a plug (33).
(34), the valve seat (35) that abuts the ball valve (34) to shut off each port (29) (30) by the return pressure oil from the hydraulic cylinder (11), and the other end of the control oil passage. A pressure adjusting bolt (39) that is attached to the side opening through a fixing bolt (37) to displace the spool (40) on the inner end side, and a return valve provided between the ball valve (34) and the spool (40). Diversion spring (36) and these plugs
(33) -Ball valve (34) -Spring (36) -Spool (40) and pressurization adjusting bolt (39) are provided on the valve body (31) in a substantially straight line. Prevention device.