JPH0221514Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Field of industrial application The present invention relates to a hydraulic jack for vertically adjusting a bed or the like and for moving other heavy objects.

(b) Conventional technology As shown in Fig. 3, a conventional hydraulic jack of this type has a hydraulic pump 2 and a ram cylinder 3 installed side by side in a tank 1, and a control lever 4 (or pedal) is depressed. pump 2 through yoke 5 by
Generally, the ram 6 is extended by operating the ram 6.

In this case, the operating range α centered on the rotation axis 7 of the operating lever 4 is the range for driving the hydraulic pump 2, or when the lever 4 is brought to the operating range β above it, the yoke 5 is The protrusion 5a opens the check valve 9 via the push ball 8. This yoke 5 has a return spring 10
It is always given a tendency to rotate clockwise. Therefore, when the operating lever 4 moves up and down within the operating range α, the hydraulic oil in the tank 1 is sucked into the pump 2 via the filter 11 and the suction check valve 12 of the hydraulic pump 2. The return movement is performed by the return spring 14. On the other hand, the downward movement of the operating lever 4 presses the plunger 13 through the yoke 5, pressures hydraulic oil from the pump 2 to the ram cylinder 3 through the check valve 15, and extends the ram 6.

When the ram 6 is then pushed to its maximum extension position,
Ring stopper 1 fitted into groove 18 of ram 6
6 comes into contact with the locking step 17 of the ram cylinder 3 and is moved slightly within the groove 18 shown in the fourth figure, opening the passage a. As a result, the hydraulic oil passes through the passages a and b and enters the passage of the ram cylinder 3. When the operating lever 4 is stopped, the ring stopper 16 is moved back to its original position to close the passage a, and the ram 6 is at its maximum extension. is maintained. Needless to say, stopping at a desired position during extension can be freely carried out by stopping the operating lever 4.

Next, the release operation for returning the ram 6 can be performed by lifting the operating lever 4 to the operating range β.
The protrusion 5a presses the push pole 8, opens the check valve 9, returns the hydraulic oil in the ram cylinder 3 to the tank 1, and the ram 6 is automatically contracted by the external force being applied. Become.

(c) Problems to be solved by the invention In the conventional product as described above, it is important to note that when the ram 6 is moved back, the check valve 9
It is essential that the operating lever 4 be in the open state, and therefore, it is necessary to hold the operating lever 4 within the operating range β against the return elasticity of the spring 10. Particularly when the ram 6 gradually contracts, it is extremely troublesome and cumbersome to hold the operating lever 4 as it is for a long period of time.

(d) Means for solving the problem Therefore, in the present invention, instead of the conventional return spring 10, a substantially triangular spring plate facing the yoke 5 is provided, and its sloped part allows the yoke to move. The yoke is locked by the flat part provided at the top end, and the pedal operation of the actuating lever 4 is continued in the operating range α, and the yoke is locked in the operating range β. This allows the locking and holding to be performed to avoid the complexity of the release operation.

The gist of the present invention will be explained below based on the embodiments shown in the drawings.

(e) Embodiment FIG. 1 is a partially cutaway side view showing an embodiment of the hydraulic jack of the present invention, and FIG. 2 is a partially cutaway enlarged side view of the return spring plate portion.

The difference between the present invention and the conventional product described above is related to the return spring 10, and the rest is the same as the cited example, so the reference numerals are also the same.

As shown in FIGS. 1 and 2, the return spring plate 20 of the present invention is bent into a substantially triangular shape, and includes a slightly curved inclined portion 21 and a flat portion 22 at the top end.
and a vertical part 23 tightened by a nut, which faces the rotation range of the tip of the yoke 5 as shown in the figure. The tip is a spring plate 20
The yoke 5 facing the inclined portion 21 is given a tendency to rotate clockwise at all times to enable reciprocating movement of the operating lever 4 when operating the pump, and within the operating range β, the tip of the yoke 5 Since the ram 6 rides on the flat portion 22 and is locked, the ram 6 continues to contract without moving back even if the operating lever 4 is released.

(g) Effects of the invention As described above, according to the invention, the return movement of the yoke 5 and the locking of the yoke 5 can be performed by a single spring plate 20, and especially in the release operation, the operation lever There is no need to manually hold the lever 4 in the operating range β or lock it with a separate locking tool, and the yoke automatically opens by simply bringing the operating lever 4 to the release range (acting range β). Since it is designed to be locked, the operation is extremely simple and efficient, and since it is a single spring plate, the structure is extremely simple, and it has the advantage that it can be used directly with conventional products. have,
The practical contribution is extremely significant.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway side view of the hydraulic jack key of the present invention, Fig. 2 is a partially cutaway enlarged side view of the spring plate portion of the same jack, and Fig. 3 is a partially cutaway side view showing an example of a conventional hydraulic jack. , FIG. 4 is a sectional view taken along line A--A in FIG. 3, and FIG. 5 is an enlarged vertical sectional side view of the pilot check valve of the ram cylinder and the vicinity of the ram base. 1...tank, 2...hydraulic pump, 3...ram cylinder, 4...operation lever (or pedal), 5
... Yoke, 6 ... Ram, 20 ... Spring plate for return, 21 ... Inclined part, 22 ... Flat part.

Claims (1)

[Scope of utility model registration request] By operating the pump within a certain range of the operating lever, the hydraulic pump is operated to extend the ram,
In a hydraulic jack equipped with a yoke that opens the hydraulic oil circuit between the ram cylinder and the tank by rotating the operating lever within the release range, a spring plate facing the yoke is provided, and the plate is provided with a spring plate for returning the yoke. A hydraulic jack characterized by forming an inclined part and a flat part for yoke locking, and releasing the yoke and locking the yoke at the same time.