JPH079902Y2 - Hydraulic jack - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic jack exclusively used for repair, which temporarily receives a bridge girder portion when repairing or replacing a gear seat portion supporting the bridge girder portion on a pier.

[0002]

2. Description of the Related Art A hydraulic jack dedicated to repairing a bridge girder part that temporarily supports the bridge girder part that supports the bridge girder part on a pier makes a plate lift by driving a wedge-shaped object. As shown in FIG. 4 and a type (hereinafter referred to as A type), a disc-shaped piston portion 2a in sliding contact with the cylinder portion 1 and a screw shaft portion continuous with the piston portion 2a are provided in the cylinder portion 1. There is a type (hereinafter referred to as B type) in which a ram portion 2 composed of 2c is provided, and a safety nut portion 5 is screwed to a screw shaft portion 2c portion thereof protruding from the cylinder portion 1.

[0003]

However, since the above-mentioned type A has a structure for driving a wedge-shaped object, not only the device itself is large and heavy, but also work for driving a wedge-shaped object is required. There is a case where the bridge girder part cannot be temporarily received on the pier where the work space is limited because it requires a separate space. In addition, in the B type, the safety nut part 5 is screwed after the bridge girder part is temporarily received. Since the ram portion 2 is structured so as to be lowered along the shaft portion 2c and tightened so as to come into contact with the upper surface of the cylinder portion 1 to prevent the ram portion 2 from loosening, in order to secure an adjustment allowance of a predetermined height, a safety nut is used. Due to the thickness of the part 5, there is a constraint that the height of the device must be increased. Furthermore, the workability is inevitable because the support of the bridge girder is released after the completion of repair / replacement of the gear seat. Remarkably bad. There are problems such as.

The present invention has been made in view of the above-mentioned conventional circumstances, and its purpose is to make it compact and lightweight without occupying the installation space and installation height, and after repairing or exchanging the rear seat part. To provide a hydraulic jack capable of smoothly returning the ram.

[0005]

[Means for Solving the Problems] The technical means taken to achieve the above-mentioned object is, in a hydraulic jack supporting a bridge girder portion on a pier, sliding contact of a ram portion with a cylinder portion into which pressure oil is injected. A piston part at the base end that fits as much as possible and the ram part fits into the cylinder part, and a rod part with a small diameter connected to the piston part, and a pressure accumulating chamber is provided in the rod part. A peripheral chamber is formed between the outer periphery and the inner periphery of the cylinder part, and the pressure accumulating chamber and the peripheral chamber are communicated with each other so that gas is enclosed in the pressure accumulating chamber and the peripheral chamber. A gist is that a thrusting head portion for lifting is mounted, and a safety nut portion that abuts a lower surface of the thrusting head portion for lifting is screwed on the outer periphery of the cylinder portion so as to be vertically movable. Further, it is effective that the thrust head portion for uplifting has a cushioning portion on its lower surface that abuts against the outer periphery of the safety nut portion.

[0006]

According to the above technical means, there are the following actions. (Claim 1) ・ The ram portion is raised by the pressure oil to bring the thrusting thrust head portion into contact with the bridge girder portion, and the outer peripheral surface of the cylinder portion is screwed so as to contact with the lower surface of the thrusting thrust head portion. Tighten the safety nut to prevent the ram from loosening and support the bridge girder stably.・ By releasing the hydraulic pressure of the cylinder part from the so-called bridge girder support state where the gas in the peripheral chamber was pressed into the pressure accumulator chamber due to the rise of the ram part, the high pressure gas accumulated in the pressure accumulator chamber was released to the peripheral chamber and automatically Return to the original position. (Claim 2) ・ By lifting the thrusting thrust head portion so that the inner surface of the buffer portion provided on the lower surface of the thrusting head portion for lifting and the outer peripheral surface of the safety nut portion are brought into contact with each other, The center position for the rod part of the thrust head is automatically set.・ External conditions (outside temperature, weight of running vehicle, etc.)
The deformation force such as expansion and contraction acting on the bridge girder is absorbed by the buffer portion interposed between the lifting thrust head portion and the safety nut portion.

[0007]

Since the present invention is the hydraulic jack constructed as described above, in the first aspect, a part of the height adjustment allowance between the cylinder portion and the supported bridge girder portion is a safety nut portion. Since the ram portion is not occupied by the ram portion and the ram portion protrudes by a predetermined amount, the hydraulic pressure in the cylinder portion is released so that the high pressure gas in the pressure accumulating chamber escapes to the same pressure in the peripheral chamber and the ram portion returns. It is possible to provide a compact and convenient hydraulic jack that does not require any space other than the installation space to automatically return the ram to its original position without resorting to manual operation. Moreover, since the ram part is notched inside to form a pressure accumulating chamber, and the rod part has a small diameter to form a peripheral chamber between the cylinder part and the inner surface of the cylinder part, it is possible to reduce the weight and, in turn, to reduce the labor of installation work. You can

According to another aspect of the present invention, the cushioning portion provided around the lower surface of the thrusting head portion for lifting is used as a positioning portion for automatically setting the center position of the thrusting head portion for lifting to the ram portion. Therefore, it is possible to promise a stable lifting force without unevenness over the entire thrust head part for lifting, and moreover, it occurs under external conditions on the bridge girder and roads supported by the bridge girder. Even if expansion deformation or contraction deformation is transmitted to the thrust thrust head portion, the deformation is not absorbed by the buffer portion interposed between the outer periphery of the safety nut portion and transmitted to the ram portion. Accident such as deformation of the head does not occur.

[0009]

Embodiments of the present invention will now be described with reference to the drawings. 1 to 3 show a hydraulic jack of the present embodiment, reference numerals A are a hydraulic jack, 1 is a cylinder portion, 2 is a ram portion, 3 is a pressure accumulating chamber, 4 is a peripheral chamber, 5 is a safety nut portion, and 6 is This is the thrust head for lifting.

The cylinder portion 1 is a cylindrical body having a closed bottom portion, and the male screw portion 1 is provided on the outer peripheral surface except the outer peripheral surface near the bottom portion.
a around the bottom, and the oil inlet 1b is provided on the side wall near the bottom.
And an oil supply hose 1c is connected to the oil supply port 1b.

The ram portion 2 is slidably fitted to the inner peripheral surface of the cylinder portion 1 via a piston portion 2a at the base end, and a rod portion 2b having a diameter smaller than that of the piston portion 2a is provided at the upper end of the cylinder portion 1. It is possible to appear and disappear from the open part.

The piston portion 2a is initially in contact with the bottom portion of the cylinder portion 1, and is separated from the bottom portion by the projecting operation of the rod portion 2b from the cylinder portion 1, as shown in FIG. When is protruded by a predetermined amount, it is brought into contact with and locked by a flange portion 1d that is provided around the open portion of the cylinder portion 1, and is controlled so that it cannot be further raised.

The pressure accumulating chamber 3 is secured over the central portion of the ram portion 2, specifically, the entire rod portion 2b.

The peripheral chamber 4 is secured between the outer circumference of the rod portion 2b and the inner peripheral surface of the cylinder portion 1, and is communicated with the pressure accumulating chamber 3 through a through hole 8.

The pressure accumulating chamber 3 and the peripheral chamber 4 are filled with an inert gas such as nitrogen gas at a predetermined pressure.

The safety nut portion 5 is formed by screwing a screw portion 5a which is screwed to the male screw portion 1a screwed on the outer peripheral surface of the cylinder portion 1, and means such as welding at an appropriate interval or disc shape on the peripheral surface. It is designed to move up and down by artificially rotating the operation handle 5b fixed at.

The thrusting head portion 6 for lifting has a substantially disc shape and is mounted so that its center is located on the rod portion 2b of the ram portion 2, and the thick portion formed at the peripheral end portion. 6a
A buffer portion 7 having a cross-sectional shape that just fits between the safety nut portion 5 and the outer peripheral surface of the safety nut portion 5 is integrally fixed to the lower surface thereof.

The cushioning portion 7 does not deform the thrust head 6 for lifting in accordance with, for example, the outside air temperature of the bridge girder B or the expansion and contraction deformation of a vehicle traveling on a road supported by the bridge girder B. As described above, it has a function of buffering the thrusting head 6 for uplifting so that it can move horizontally, and a function of setting the center position of the thrusting head 6 for uplifting with respect to the rod portion 2b.

The method of using the hydraulic jack of this embodiment will be briefly described below. As shown in FIG. 1, the pier C and the bridge girder B are connected to each other.
At the time of repairing or exchanging the gear seat portion D that supports the space between and, the hydraulic jack A of this embodiment is installed on the upper surface of the pier C adjacent to the gear seat portion D. Then, by supplying pressure oil from the oil filling port 1b through the oil filling hose 1c into the cylinder portion 1, the ram portion 2 rises and the thrusting head portion 6 for uplifting in which the center position is aligned with the rod portion 2b. The thrusting head 6 for lifting is brought into contact with the lower surface of the lifting bridge girder B. At this time, the volume of the peripheral chamber 4 is reduced and
Gas flows out to the pressure accumulating chamber 3, and the pressure in the pressure accumulating chamber 3 becomes high.
Next, the safety nut portion 5 is rotated and raised so as to come into contact with the inner peripheral surface of the buffer portion 7 fixed to the lifting thrust head portion 6 and tightened to prevent the ram portion 2 from loosening. As a result, the bridge girder B is permanently supported by the hydraulic jack A of this embodiment. Cylinder part 1 after repair / replacement of gear seat D
When the hydraulic pressure acting on the inside is released, the ram portion 2 is automatically lowered by the pressure of the gas stored in the pressure accumulating chamber 3 and returns to the original position. Incidentally, the gas returns from the pressure accumulating chamber 3 to the peripheral chamber 4 through the through hole 8.

[Brief description of drawings]

FIG. 1 is a cutaway front view showing a use state.

FIG. 2 is a vertical cross-sectional view of the hydraulic jack of this embodiment.

FIG. 3 is a vertical sectional view of the hydraulic jack showing a state in which a ram portion is raised.

FIG. 4 is a vertical sectional view of a conventional hydraulic jack.

[Explanation of symbols]

A: Hydraulic jack 1: Cylinder part 2: Ram part 2a: Piston part 2b: Rod part 3: Accumulation chamber 4: Peripheral chamber 5: Safety nut part 6: Thrust head part for lifting 7: Buffer part B: Bridge girder part C : Pier D: Crane seat

Claims (2)

[Scope of utility model registration request] 1. A hydraulic jack for supporting a bridge girder portion on a pier, wherein a ram portion is slidably fitted to a cylinder portion into which pressure oil is injected, and the ram portion is fitted to the cylinder portion. It is composed of a piston part at the end and a small diameter rod part connected to the piston part, and a pressure accumulating chamber is formed in the rod part, and peripheral chambers are formed between the rod part outer circumference and the cylinder part inner circumference, respectively. The pressure accumulating chamber and the peripheral chamber are communicated with each other to enclose gas in the pressure accumulating chamber and the peripheral chamber, and the thrust head part for lifting the bridge girder part is mounted on the rod part, and the thrust head part for supporting the bridge part is mounted on the rod part. A hydraulic jack characterized in that a safety nut portion that comes into contact with the lower surface of the lifting thrust head portion is screwed around the outer periphery so as to be vertically movable. 2. The hydraulic jack according to claim 1, wherein the thrust head portion for uplifting has a buffer portion on its lower surface that is in contact with the outer periphery of the safety nut portion in a protruding shape.