JP3019390U - Safety valve structure of jack - Google Patents

Abstract

(57) [Summary] [Purpose] The objective is to provide a safety valve that operates accurately at a constant pressure. [Structure] In a valve body 1a of a check valve 1 fitted inside a pump seat 6, an annular groove 11 is provided at a position of a horizontally oriented oil absorption pipe 61, and an annular groove 11 is provided over the entire circumference thereof. An L-shaped oil suction hole 12 provided with a downward check valve 12a therebetween, an oil output hole 13 provided with an upward check valve 13a penetrating between the upper and lower surfaces, and an annular groove and an upper side of the check valve of the oil output hole. A safety valve hole 14 is formed in the radial direction between the safety valve hole 14a and the safety valve 14a inserted in the safety valve hole 14a.
And an annular adjusting screw 4.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a check valve for a hydraulic jack, and more particularly to a check valve provided with a safety valve.

[0002]

[Prior art]

 The conventional hydraulic jack is provided with a check valve in the oil tank and the pump seat 6 of the hydraulic pump 7, and this check valve prevents the reverse flow of the oil entering the pump seat 6 from the oil tank to operate the lever socket 5. As the piston moves up and down, the pressure oil is supplied to the jack's pressure cylinder, and the piston in the pressure cylinder is pushed up to push up heavy objects.

In this case, a safety valve is provided to automatically limit the upper limit value of the hydraulic pressure so that the hydraulic pressure does not exceed the limit value even if the jack load becomes excessive. Damage to the hydraulic system must be prevented.

However, the conventional safety valve mainly mounts a steel ball, a spring and an adjusting screw in the valve hole, and adjusts the adjusting screw to adjust the pressing force of the steel ball by the spring to control the upper limit of the hydraulic pressure. It is a thing.

When the hydraulic pressure in the cylinder becomes larger than the pressing force of the spring against the steel ball, the steel ball is pushed back to release the blockage of the valve hole, and the pressure oil flows out from the valve hole to reduce the pressure in the cylinder. , Prevent burst damage to the jack.

[0006]

[Problems to be solved by the device]

 In the above-mentioned operation of the safety valve by combining the steel ball and the spring, the deviation of the operation start pressure due to the wobbling of the steel ball is large, and it is difficult to maintain a constant upper limit pressure.

An object of the present invention is to solve the above-mentioned problems and provide a safety valve that operates reliably at a constant pressure.

[0008]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, in a hydraulic pressure generation pump of a hydraulic jack, a pump seat 6 having an oil absorption pipe 61 and an oil discharge pipe 62 formed between the outside and a cylindrical internal space is provided. , The cylinder 7a of the pump 7 provided with a piston which is screwed and fixed to the upper side of the pump seat 6 and which is moved up and down from the outside, and the inner space of the pump seat 6 are fitted to the lower end of the cylinder. In the hydraulic pump provided with the check valve 1 which is inserted closely, the valve body 1a of the check valve 1 fitted in the cylindrical internal space of the pump seat 6 has the outer periphery of the valve body 1a. An annular groove 11 is provided in the middle part and at a position including the oil absorption pipe 61 over the entire circumference, and an L-shaped downward check valve 12a is provided between the annular groove 11 and the upper surface of the valve body 1a. L type sucking Between the hole 12, the oil output hole 13 which penetrates the upper and lower surfaces of the valve body 1a and is provided with an upward check valve 13a, and between the annular groove 11 and the oil output hole 13 above the check valve 13a. The safety valve 14a is inserted into the drilled safety valve hole 14.

The safety valve hole 14 has a small diameter hole 141 on the oil output hole 13 side and a large diameter hole 142 on the annular groove 11 side, and a female screw is threaded on the end portion on the annular groove 11 side to ensure safety. The valve 14a has a pin 2 formed of a rod rod 22 of different diameter provided with a conical body 21 on the side of the small diameter hole 141, and a spring 3 for inserting the tip portion of the conical body 21 of the pin 2 into the small diameter hole 141 for elastically closing it. And a ring-shaped adjusting screw 4 in which a hole 41 for loosely fitting the small diameter portion at the tip of the different-diameter rod column 22 penetrating the spring 3 is bored and screwed into the female screw of the safety valve hole 14. It has been done.

[0010]

[Action]

 As described above, since the tip side of the safety valve 14a is the conical body 21, even if the hydraulic pressure slightly exceeds the set value, the conical body 21 moves back linearly stably, and the conical body 21 guides the oil outflow. And the pressure oil flows out smoothly.

[0011]

【Example】

 1 is a vertical cross-sectional view of a pump seat including a check valve, FIG. 2 is a perspective view of an example of a hydraulic jack, and FIG. 3 is a perspective view of a state in which the check valve is pulled up from the pump seat.

As shown in the perspective view of FIG. 2 and the sectional view of the pump seat of FIG. 1, the jack of the present invention has a pump 7 composed of a cylinder 7 a and a piston fixed on the pump seat 6, and a pump 7. A lever socket 5 for driving the vertical movement of the piston by a lever, and a jack body 8 for pushing up a heavy object by the pressure oil generated by the pump 7.

As shown in FIGS. 1 and 3, the inside of the pump seat 6 has a vertical cylindrical space inside the pump seat 6, which penetrates the pump seat 6 at an intermediate position substantially above and below this side surface. An oil absorption pipe 61 is provided, and an L-shaped oil output pipe 62 is formed from the downward direction to the horizontal direction at the center of the conical bottom surface. The oil absorption pipe 61 is provided in an oil tank (not shown). The oil outlet pipe 62 communicates with the cylinder of the jack body 8 shown in FIG.

An internal thread is threaded on the upper end of the cylindrical space, and the cylinder 7 a of the pump 7 is screwed and fixed to this portion. A cylindrical check valve 1 is fitted between the lower end of the cylinder 7a and the conical bottom surface of the cylindrical space.

An annular groove 11 is formed over the entire circumference at an intermediate portion (a position including the oil absorption pipe 61) of the side surface (cylindrical surface) of the valve body 1a of the check valve 1. Further, an oil suction port 121 is formed in a lateral direction at a position facing the oil suction pipe 61 at the bottom of the annular groove 11, and a filter 122 is housed inside, and a valve is provided from the upper side surface of the oil suction port 121. The L-shaped oil absorption hole 12 is formed as a whole by forming an oil absorption hole penetrating the upper surface of the main body 1a.

A vertical portion of the L-shaped oil suction hole 12 (a portion communicating with the pump 7) has a large diameter in the middle thereof, and a downward check valve 12 a including a steel ball 123 and a compression spring 124 is formed. . The portion open to the pump 7 side has a small diameter by a throttle or other method to prevent the compression spring 124 from falling off.

Further, an oil outlet hole 13 is vertically penetrated along the center axis of the valve body 1a, and the lower portion of the oil outlet hole 13 is similar to the check valve 12a of the L-shaped oil suction hole 12 described above. An upward check valve 13a including a steel ball 131 and a compression spring 132 is provided in such a structure.

Further, a safety valve hole 14 is bored in the radial direction of the valve body 1 a between the oil outlet hole 13 on the upper side of the check valve 13 a and the annular groove 11. The safety valve hole 14 is formed with a small diameter hole 141 on the oil discharge hole 13 side and a large diameter hole 142 on the annular groove 11 side, and a female screw is attached to the outlet of the large diameter hole 142 on the annular groove 11 side. It is threaded.

In the above-mentioned safety valve hole 14, a pin 2 composed of a conical body 21 having an apex on the side of the small diameter hole 141, and a rod column 22 of a two-step diameter with a thin tip on the bottom side thereof, The coil-shaped spring 3 in which the rod column 22 is inserted so as to press the tip of the conical body 21 at the tip of the pin 2 into the small diameter hole 141, and the thin tip portion of the rod column 22 having the two-step diameter loosely fits into the hole 41. The safety valve 14a is configured with the adjusting screw 4 that is fitted, and the adjusting screw 4 is screwed into the female thread on the outlet side of the safety valve hole 14 to adjust the pressing force against the small diameter hole 141 of the conical body 21. Is configured to adjust.

Next, the operation of the above check valve 1 will be described. In a normal use state, when a piston (not shown) of the pump 7 is pulled up via the lever socket 5, oil passes from the oil tank (not shown) into the cylinder 7a through the oil absorption pipe 61, and solid matters are removed by the filter 122. The steel ball 123 is pushed up against the compression spring 124 and supplied from the L-shaped oil absorption hole 12. Then, when the piston is pushed down through the lever socket 5, the oil in the cylinder 7a is blocked from the L-shaped oil suction hole 12 by the check valve 12a, so it passes through the oil output hole 13 and pushes the check valve 13a down. And flows out to the lower side of the valve body 1a, flows into the cylinder (not shown) of the jack body 8 from the oil outlet pipe 62, and operates as a pushing force of the jack.

In this case, if the load of the jack is excessive, the cylinder of the jack body 8 and the cylinder 7a of the pump 7 are inevitably subjected to an excessive internal pressure, and in some cases, an accident such as a rupture of the cylinder occurs. Is concerned.

In order to prevent this, when the set pressure lower than the limit value is reached, the internal oil is leaked and the internal pressure is adjusted so as to lower the internal pressure. When the set pressure is exceeded, it is necessary to operate promptly to let out the pressure oil, but the cone body 21 and the spring 3 described above enable fine adjustment even if the pressure is slightly exceeded and the pressure oil flows out. Also, fine outflow is possible along the cone 21. By setting the pressure setting value of the safety valve 14a to be slightly lower than the limit value, it is possible to operate before the occurrence of a rupture accident and obtain the maximum pushing force close to the limit value. .

[0023]

[Effect of device]

 As mentioned above, the maximum pressure of the cylinder in the jack is automatically controlled, and it is possible to use the maximum pushing force before failure.

Further, when the set pressure is exceeded, the flow path of the pressure oil flowing out from the small diameter hole 141 can smoothly flow out by the conical body 21, the pressure drop is accurate and the variation is small, and it is better than the case where the steel ball is used. It is easy to maintain the set pressure.

Since the center of the rear end of the rod column 22 of the safety valve 14a is held, the backward movement of the conical body 21 is linear and stable operation is possible.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a pump seat including a check valve.

FIG. 2 is a perspective view of an example of a hydraulic jack.

FIG. 3 is a perspective view showing a state where a check valve is pulled up from a pump seat.

[Explanation of symbols]

 1 Check valve 1a Valve body 11 Annular groove 12 L type oil absorption hole 12a Check valve 13 Oil outlet hole 13a Check valve 14 Safety valve hole 2 Pin 21 Conical body 22 Rod column 3 Spring 4 Adjustment screw 6 Pump seat 61 Oil absorption pipe 62 Oil output pipe 7 Pump 7a Cylinder 8 Jack body

Claims (2)

[Scope of utility model registration request] 1. A pump for generating hydraulic pressure of a hydraulic jack, which is screwed and fixed to an upper side of a pump seat in which an oil absorption pipe and an oil output pipe are formed between the outside and a cylindrical internal space is provided. In a hydraulic pump provided with a cylinder of a pump provided with a piston that is vertically moved from the outside, and a check valve that fits into the internal space of the pump seat and is closely inserted into the lower end of the cylinder. The valve body of the check valve fitted in the cylindrical inner space of the pump seat is opened over the entire circumference at an intermediate portion of the outer circumference of the valve body and at a position including the oil absorption pipe. An annular groove, an L-shaped oil absorption hole having an L-shaped downward check valve provided between the annular groove and the upper surface of the valve body, and an upward check valve that penetrates through the upper and lower surfaces of the valve body. Oil output with valve A safety valve for a jack, comprising a hole and a safety valve inserted into a safety valve hole formed between the annular groove and an upper side of the check valve of the oil outlet hole. Construction. 2. The safety valve hole has a small diameter hole on the oil output hole side, a large diameter hole on the annular groove side, and a female screw threaded on an end portion on the annular groove side. A pin composed of a rod rod with a different diameter provided with a cone on the side of the small diameter hole, a spring that inserts the tip of the cone of the pin into the small diameter hole to close it by pressure, and the rod with a different diameter that penetrates the spring. 2. The jack according to claim 1, wherein a hole for loosely fitting a small diameter portion at the tip of the pillar is formed, and the hole is constituted by an annular adjusting screw screwed into the female screw of the safety valve hole. Safety valve structure.