JPH0735492U - Multi-stage ram lift - Google Patents

Abstract

(57) [Abstract] [Purpose] The ascending / descending sequence is reliably controlled, and when descending, descends from the first ram side with the larger diameter side, and further, a large surge pressure is unlikely to occur even during a sudden stop. Provide a lift. [Structure] The first ram and the second ram are housed in a cylinder in a telescopic manner, a partition plate is provided at the bottom of the first ram, and a partition plate is provided with a through hole serving as a valve chamber having an upper opening upward. , A non-return ball valve element is housed in the valve chamber, and below the ball valve element, when the first ram descends to the lowermost end, the lower end contacts the bottom surface of the cylinder and pushes up the valve operation rod. It is mounted so that it can be raised and lowered.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an improvement of a multi-stage ram type lift in which a first ram 20 and a second ram 30 are telescopically housed in a cylinder 10.

[0002]

[Prior art]

 Conventionally, as shown in FIG. 4, various multi-stage ram type lifts have been proposed in which a plurality of rams 20, 30 ... Each having a smaller diameter are housed in a cylinder 10 in a telescopic manner. Type lifts are becoming more and more widely used recently because they have the advantage that the depth of the storage pit can be set shallow when the lift body is buried under the floor.

[0003]

[Problems to be solved by the device]

 However, the above-mentioned conventional multi-stage ram type lift is generally for controlling the ascending / descending order of a plurality of rams 20, 30 ... (The outer ram is referred to as the first ram 20, and the inner ram is referred to as the second ram 30). Since no mechanism is attached, there is a difference in the time required to move up and down to a certain position, which may interfere with the interlocking with other equipment. Normally, it descends from the second ram 30, and if a sudden stop is made when only the second ram 30 descends, a large surge pressure will be generated in the cylinder 10 and the heavy object W or the hydraulic circuit to be mounted will be impacted and the heavy object will be impacted. There was a problem that it could cause the product to drop or the hydraulic circuit to be damaged.

That is, the ascending / descending order of the conventional multi-stage ram type lift will be described below with reference to FIG. 5 when no load is applied and when a load is applied midway, with reference to FIG.

[Normal Lifting Order in Unloaded State] First, in the normal lifting order in the unloaded state, both the first ram 20 and the second ram 30 in “FIG. 5” descend to the lowest end. When the oil is press-fitted into the cylinder 10 from the state (A), the first ram 20 and the second ram 30 are usually integrally lifted together to the state (B). Then, when the first ram 20 rises to the ascending end, the first ram 20 comes into contact with a stopper or the like and cannot rise, and when the oil is press-fitted into the cylinder 10, only the second ram 30 this time. Rises to the state of (C). When the lift is lowered, contrary to the above, the state of (C) of FIG. 5 is returned to the state of (A) via the state of (B).

[Special lifting sequence in no load state] However, the above-described lifting operation sequence is not guaranteed by a special mechanism therefor, and in some cases, only the second ram 30 may be provided in the initial stage of lifting. In some cases, the first ram 20 rises (the first ram 20 stops), the second ram 30 rises to the rising end, and then the first ram 20 rises together with the second ram 30. That is, it is possible that the ram 20 moves up and down through the state of (D) of "Fig. 5", which is caused by the weight difference between the first ram 20 and the second ram 30 and the ram and its metal. Depending on which of the first ram 20 side and the second ram 30 side has a larger frictional resistance value.

“Normal ascending order during intermediate load” “FIG. 6” is for embedding a lift below the floor surface F and attempting to lift a heavy object W placed on the floor surface F. First, When oil is press-fitted into the cylinder 10 from the state (A) in which both the first ram 20 and the second ram 30 are lowered to the lowermost end, no load is initially applied. The ram 20 and the second ram 30 are integrally lifted together to be in the (B1a) state, but in some cases, only the first ram 20 is lifted to be in the (D1) state. Then, when the second ram 30 comes into contact with the heavy object W in the state of (D1), the second ram 30 stops temporarily rising due to the load, and the first ram 20 rises to the state of (B1b). The state is the same as (B 1a). Then, when a load is applied to both the first ram 20 and the second ram 30 in the states (B1a) and (B1b), this time, the first ram 20 and the second ram 30 are integrally lifted together. The state of (B) is obtained. Then, when the first ram 20 rises to the ascending end, the first ram 20 comes into contact with a stopper or the like to make it impossible to rise, and when oil is pressed into the cylinder 10, the second ram 30 will then move. The rise in the state becomes the state of (C) as in the case of no load.

“Special ascending order during intermediate load” However, when the load is largely deviated in the state of (D1), the first ram 20 and the second ram 30 are integrated from the state of (D1). In some cases, it will rise to the state of (E). In other words, when the first ram 20 becomes unable to slide with the "crown" second ram 30 due to an eccentric load, the first ram 20 rises when the second ram 30 does not finish rising. Sometimes.

“Normal load descending sequence” When descending with a load applied, the second ram 30 descends first, and after the second ram 30 finishes descending, the first ram 20 then separates the second ram 30. Descends with.

However, when the load is an eccentric load, the first ram 20 and the second ram 30 are integrally lowered, and after the first ram 20 is completely lowered, the second ram 20 is finished. 30 may descend.

That is, in the conventional multi-stage ram lift, the order of raising and lowering each ram may be out of order as described above, and if the order of raising and lowering occurs in a special case, it also affects the speed of raising and lowering. However, there is a problem in that the control becomes complicated and there may be a problem in interlocking with other devices.

In addition, when the heavy load W is lowered from a high place to a low place, this kind of multi-stage ram lift first descends from the side of the second ram 30 having a small diameter, as described above. Contrary to the principle that it is desirable that the descending speed is fast and that it is desirable to be slow for safety reasons at high places and when starting, and if the lift is suddenly stopped when only the second ram 30 is descending, the second ram 30 will have a small diameter. Therefore, the condition that the descending speed is fast is combined, and a considerably large surge pressure is generated in the cylinder 10. It is also assumed that this large surge pressure causes the second ram 30 to suddenly stop more than necessary and becomes an impact force against the inertia of the loaded heavy object W, causing the heavy object W to bounce and be displaced. Further, it is assumed that this large surge pressure will also affect the hydraulic circuit connected to the cylinder 10 and may cause damage to the hydraulic circuit.

Therefore, the present invention has been made in view of the above problems, and the ascending / descending order is reliably controlled, and when descending and descending, descending from the first ram side having the larger diameter side (to be exact, the first ram together with the second ram). Moreover, the purpose is to provide a multi-stage ram lift in which a large surge pressure is unlikely to occur even during a sudden stop.

[0014]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the first ram 20 and the second ram 30 are housed in the cylinder 10 in a telescopic manner in order to solve the above-mentioned problems. In the multi-stage ram lift configured as described above, a partition plate 21 is provided at the bottom of the first ram 20, and a partition hole 21 is provided in the partition plate 21. A ball valve body 40 for check is housed in the ball valve body 40. Below the ball valve body 40, when the first ram 20 descends to the lowermost end, the lower end contacts the bottom surface 13 of the cylinder 10 and the ball valve body 40. This is a technical means in which a valve operating rod 45 for pushing up is attached so as to be able to move up and down.

[0015]

[Action]

 Therefore, in the multi-stage ram type lift according to the present invention, the first ram 20 and the second ram 30 are integrated into the first ram 20 at the beginning of the lift regardless of the presence or absence of the load because the through hole 42 resists the inflow of oil. As the ram 20 rises, it acts so that only the second ram 30 rises after the first ram 20 reaches the end of the rise. In the rare case of no load, if the diameter of the through hole 42 is large, only the second ram 30 may rise first, but in this case, when the second ram 30 receives a load, the through hole 42 The first ram 20 and the second ram 30 are integrally formed from the beginning because the first ram 20 is lifted up to a position where the first ram 20 receives the load before a large load is applied to the second ram 30 due to the inflow resistance of the oil. However, there is no practical problem even if it is considered to have risen.

Since the ball valve body 40 closes the through hole 42 and closes the valve when it descends, the oil in the second ram 30 does not flow away and the first ram 20 and the second ram 30 are integrated. When the first ram 20 descends to the lowermost end, the ball valve body 40 is pushed up, and thereafter the second ram 30 acts so as to descend.

The through-hole 42 acts as a resistance by narrowing the flow path when the oil flows through, and acts as a buffer when a large surge pressure is generated in the second ram 30, and the heavy load W and This is to reduce the impact on the piping.

[0018]

【Example】

 An embodiment of the present invention will be described below with reference to the accompanying drawings. In the figure, 10 is a cylinder, and this cylinder 10 has an upper opening 11, and a first metal 12 is fixed inside the upper opening 11. The bottom of the cylinder 10 is sealed by a bottom plate 13, and an oil inlet / outlet 14 is provided at an appropriate position (a peripheral surface portion in the illustrated example). Then, the pump 51 of the pump unit 50 shown in FIG. 3 is operated to press the oil in the tank 52 into the cylinder 10 through the inlet / outlet port 14 to raise the rams 20 and 30 which will be described later, thereby removing the oil in the cylinder 10. As in the conventional case, the rams 20 and 30 are lowered by operating the switching valve 53 in the tank 52 so that the tank 52 can recirculate. In FIG. 3, reference numeral 54 is a filter, 55 is a check valve, and 56 is a flow rate adjusting valve. These are also well known in the art, and therefore detailed description thereof will be omitted.

The first ram 20 is housed in the cylinder 10 so that it can be moved up and down, and the second ram 30 is housed in the first ram 20 so that it can be moved up and down, as in the prior art. The outer peripheral surface of the first ram 20 is slidable while maintaining airtightness with respect to the first metal 12 so that the first ram 20 can move up and down. Further, the first ram 20 is formed in a tubular shape, and the second metal 22 is provided inside the upper opening 21, and the outer peripheral surface of the second ram 30 is slidable while keeping the second metal 22 airtight. However, it is possible to move up and down. Also, the second ram 30 has a column or a bottom 29 or a lid 28 (in the illustrated example, has both the bottom 29 and the lid 28) to prevent oil in the cylinder 10 from leaking. It is the same as the conventional telescopic multi-stage ram lift.

According to the present invention, a partition plate 21 is provided at the bottom of the first ram 20, and the partition plate 21 is provided with a through hole 42 which is a valve chamber 41 having an upper opening upward. A ball valve body 40 for check is housed in 41, and when the first ram 20 descends to the lowermost end below this ball valve body 40, the lower end comes into contact with the bottom surface 13 of the cylinder 10 and the ball valve body 40. A valve operating rod 45 for pushing up is attached so as to be able to move up and down.

The partition plate 21 is fixed to the bottom of the first ram 20 with fixing screws 22, 22, 22 ... And is installed so as to partition the inside of the first ram 20 and the inside of the cylinder 10. Further, the partition plate 21 is provided with a through hole 42 which forms a valve chamber 41 having an upper opening upward, and the inside and the outside of the first ram 20 are communicated with each other at a portion of the valve chamber 41 and the through hole 42. There is.

It is needless to say that the bottom portion of the valve chamber 41 is communicated with the through hole 42 and the valve seat portion 41a is provided. In this embodiment, the valve seat packing 43 is provided in the valve seat portion 41a. The valve seat packing 43 is sandwiched between the lower end of the tapered valve seat portion 41 a whose diameter is reduced downward and the upper end of the pressing ring 44 fitted from below the partition plate 21. Yes. The pressing ring 44 is provided with a taper surface portion 44a adapted to the taper surface extension surface portion of the valve seat portion 41a so that even if the valve seat packing 43 is crushed, the ball valve body 40 is damaged or the sealing is lost. I have been told not to.

In the illustrated example, the valve operating rod 45 is held by a holding ring 46, which is placed on the lower surface side of the holding ring 44, so as to be able to move up and down. The holding ring 46 is attached to an outer peripheral portion of a mounting ring portion 46a. A holding ring portion 46b for loosely inserting the valve operating rod 45 is provided at the center, and the mounting ring portion 46a and the holding ring portion 46b are connected by radial arms 46c, 46c, 46c. The valve operating rod 45 loosely inserted in the holding ring portion 46b has a spring 46d disposed between the holding ring portion 46b and the lower end portion of the valve operating rod 45, and the valve operating rod 45 moves downward. It is designed to be urged towards. The pressing ring 44 and the holding ring 46 are fixed to the partition plate 21 together with fixing screws 48, 48, 48 ....

Although the present application has been described with a two-stage type, it is needless to say that it can be applied to a multi-stage type of three or more stages. Further, in the figure, 60 is an air vent valve, 61 is an air vent conduit, 62 is a pop-out prevention bar of the ball valve body 40, and 63 is a straightening plate.

[0025]

[Effect of device]

 Since the present invention is as described above, it is possible to provide a multi-stage ram type lift in which the ascending / descending order can always be predicted.

The present invention raises and lowers the first ram 20 having a large diameter both at the time of ascending start and at the time of descending start. Therefore, it is possible to provide a multi-stage ram type lift which is slow in starting and has high safety. .

Further, in the present invention, assuming a case where the second ram 30 suddenly stops when moving up and down, a large surge pressure is generated in the first ram 20, and this surge pressure is a hydraulic pressure when there is no conventional partition plate 21. Since it will affect even the piping etc., it is necessary to prepare in advance a strong piping etc. that can withstand this kind of surge pressure, but in the present invention, the oil is narrow when the second ram 30 suddenly stops with a high surge pressure. By passing through the through-hole 42, a cushioning action is exhibited, the influence of piping, etc. can be reduced, and the partition plate 21 also exhibits a cushioning action against the impact at the time of sudden stop, so that the heavy load W is prevented from falling. It is possible to provide a safe multi-stage ram lift without fear.

[Brief description of drawings]

FIG. 1 is a partially sectional front view showing an embodiment of a multi-stage ram type lift according to the present invention.

FIG. 2 is a sectional view of a partition plate used in the present invention.

FIG. 3 is a hydraulic circuit diagram.

FIG. 4 is a schematic view of the present invention and a conventional multi-stage ram type lift.

FIG. 5 is a front view illustrating an operation sequence.

FIG. 6 is a front view for explaining another operation sequence.

[Explanation of symbols]

 10 cylinder 13 bottom surface 20 first ram 21 partition plate 30 second ram 41 valve chamber 40 ball valve body 45 valve operating rod

Claims (1)

[Scope of utility model registration request] 1. A first ram (20) in a cylinder (10).
A multi-stage ram type lift in which the first ram (20) and the second ram (30) are housed in a telescopic shape, a partition plate (21) is provided at the bottom of the first ram (20),
This partition plate (21) has a valve chamber (4
1) is provided with a through hole (42), a ball valve body (40) for check is housed in the valve chamber (41), and the first ram is provided below the ball valve body (40). When the lower end (20) descends to the lowermost end, the lower end contacts the bottom surface (13) of the cylinder (10) and pushes up the ball valve body (40).
5) A multi-stage ram type lift that can be lifted and lowered.