JPH0532397A - Correction method for tuning shift in cylinder mechanism of vehicle maintenance lift - Google Patents

Abstract

PURPOSE:To adjust plural number of cylinder mechanisms so that the heights of pistons become the same at the lowest positions. CONSTITUTION:Each piston 6 is pressed down compulsively until it reaches the lowest limit, by continuing pressing force of the piston 6 though a little even after a check valve 17 is opened, providing a diaphragm intentionally to a communicating path 15 communicating both cylinder chambers 1a, 1b. Its reliability is high and it is able to be utilized without anxiety, as the piston 6 is pressed down till the lowest limit certainly thereby at every lift down operations.

Description

Detailed Description of the Invention

[0001]

[Industrial field of application] A plurality of double-acting cylinder mechanisms for raising and lowering a vehicle support are connected in series, and each cylinder mechanism is caused to move up in synchronization, and the piston is forcibly lowered by the reverse flow of hydraulic oil. The present invention relates to a method for correcting a synchronization shift in a cylinder mechanism of a vehicle maintenance lift to be operated.

[0002]

2. Description of the Related Art As a method of correcting a synchronization deviation in a cylinder mechanism of a vehicle maintenance lift, as shown in FIG.
The piston 6 is provided with a communication passage 15 that communicates the two cylinder chambers 1a and 1b with each other.
A check valve 17 having a check function for b is provided, and a push-up pin 20 is provided on the bottom surface of the lower cylinder chamber 1b so as to lower the piston 6 by the reverse flow of the hydraulic oil, so that the piston 6 approaches the lower limit position. When dropped, the ball 17a is lifted up by the push-up pin 20 and the check valve 17 is opened so that hydraulic fluid can pass from the upper cylinder chamber 1a to the lower cylinder chamber 1b, from which the piston 6 naturally descends. Has reached the lower limit, the height of the piston 6 has been adjusted to the same level at the lower limit position, and an attempt has been made to allow the hydraulic fluid to pass through the cylinder without resistance.

[0003]

The idea of correcting the piston at the lower limit position in the case where there is a synchronization deviation by operating the hydraulic pressure in the opposite direction and forcibly lowering it is theoretically true, but in reality Both pistons may not fully reach the lower limit due to sliding resistance, oil viscosity resistance, etc.
As a result, there was a risk that it would not be corrected, or something that had been perfectly synchronized until then would cause a new position shift, which would rather increase the risk.

[0004]

SUMMARY OF THE INVENTION According to the present invention, the piston reaches the lower limit by intentionally providing a throttle in the communication passage and maintaining the piston pressing force slightly even after the valve is opened. It is pushed down until it does, and the level is surely adjusted.

[0005]

[Effect] Every time the lift-down operation is performed, the piston position is corrected so as to match the lower limit for the purpose of confirmation. Therefore, no trouble is required, and the best synchronization condition is always maintained, which is highly reliable. .

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example in which a method for correcting a tuning deviation in a cylinder mechanism according to the present invention is carried out in an embedded lift will be described with reference to the drawings. Reference numerals 1 and 2 denote a pair of double-acting cylinder mechanisms (hereinafter simply referred to as cylinder mechanisms) housed in a pit 4 in a vertical posture with the protruding directions of the piston rods 3 and 3 facing upward. At the upper end of 3, drive-on plates 5 and 5 which are vehicle supports.
The cylinder mechanisms 1 and 2 are connected in series by a reversible oil passage described later. Since the cylinder mechanisms 1 and 2 are of the same model and therefore confusing, 1 will be distinguished as a drive side cylinder mechanism and 2 as a driven side cylinder mechanism in the following description.

The inside of each cylinder mechanism 1, 2 is a piston 6
Is divided into upper and lower cylinder chambers, and the upper cylinder chamber 1a of the drive side cylinder mechanism 1 and the lower cylinder chamber 2b of the driven side cylinder mechanism 2 are connected by a communication oil passage 7, and the lower cylinder chamber 1b of the drive side cylinder mechanism 1 is connected. The upper cylinder chamber 2a of the driven side cylinder mechanism 2 is connected to the switching valve 10 via the feed oil passage 8 and the return oil passage 9, respectively. Further, the switching valve 10 is provided with a pump 11, and is connected with a pressure feed passage 13 for feeding the working oil in the oil tank 12 and a return passage 14 for sending the working oil back to the oil tank 12, and this hydraulic circuit is constructed as described above. By operating the switching valve 10, the pressure feed passage 13 and the return passage 14 are directly connected to each other, and the pressure feed passage 13 and the feed oil passage 8 are connected to each other, and the return oil passage 9 and the return passage 14 are connected to each other, so that the working oil is driven. The ascending side for feeding the working oil into the lower cylinder chamber 1b of the cylinder mechanism 1 and returning the working oil in the upper cylinder chamber 2a of the driven side cylinder mechanism 2 to the oil tank 12 for positive circulation, the pressure feed passage 13 and the return oil passage 9, Also, the feed oil passage 8 and the return passage 14 are connected to each other to feed the working oil into the upper cylinder chamber 2a of the driven side cylinder mechanism 2 and forcibly lift it down to drive the cylinder side 2 of the drive side.
A reversible configuration is adopted in which the working oil in the lower cylinder chamber 1b is switched to the descending side which circulates in the opposite direction to return to the oil tank 12 (FIG. 2).

Next, the respective cylinder mechanisms 1 and 2 will be described. Since both cylinder mechanisms are the same, only the drive side cylinder mechanism 1 will be described. The piston 6 is attached to the piston 6 when the piston rod 3 is fixed to the rod. Is formed with a lateral hole 15a penetrating in the direction orthogonal to the axial direction of the cylinder and a vertical hole 15b penetrating the center of the piston portion. Inside the vertical hole 15b, the upper and lower cylinder chambers 1a, 1a are provided.
Check valves 16 and 17 having a check function for b are provided respectively, and a bush 18 for narrowing the hole diameter to form a throttle is press-fitted into the lateral hole 15a.

The lower end of the piston 6 has a through hole 1 at the center.
9a is provided, and the through hole 1 is provided.
The push-up pin 20 is hung on the ring 9a with the ring body 20a fitted in the middle part thereof locked and the lower end protruding downward. As a result, when the piston 6 is rising, the check valves 16 and 17 work to prevent the hydraulic oil from flowing in and out between the cylinder chambers 1a and 1b (a in FIG. 1), and when the piston 6 is lowered, the pin holder 19 causes the cylinder 6 to move. Immediately before coming into contact with the bottom surface of the chamber 1b, the push-up pin 20 comes into contact with the bottom surface of the cylinder chamber 1b and is pushed up, and the ball 17a of the check valve 17 is pushed up by the push-up pin 20 and the check valve 17 is opened. The flow of hydraulic oil is allowed from the upper cylinder chamber 1a to the lower cylinder chamber 1b (FIG. 1b).

In the embedded lift thus formed, when the switching valve is switched to the rising side during lift-up, the hydraulic oil in the oil tank is fed into the lower cylinder chamber 1b of the drive side cylinder mechanism 1 by the pump,
The piston 6 of the drive side cylinder mechanism 1 is pushed up, whereby the hydraulic oil in the upper cylinder chamber 1a of the drive side cylinder mechanism 1 is sent out to the lower cylinder chamber 2b of the driven side cylinder 2 via the connecting oil passage 7, and the driven side The piston 6 of the cylinder mechanism 1 is pushed up in synchronism with the piston 6 of the drive side cylinder mechanism 1, the hydraulic oil in the upper cylinder chamber 2a of the driven side cylinder mechanism 2 is returned to the oil tank, and the upper side of the drive side cylinder mechanism 1 is returned. By setting the cross-sectional areas of the cylinder chamber 1a and the lower cylinder chamber 2b in the driven side cylinder mechanism 2 to be equal, both pistons 6, 6 are raised synchronously.

When the switching valve is switched to the descending side, the operation opposite to the lift-up operation is performed and both pistons 6, 6 are forcibly pushed down. When the piston 6 reaches the lower limit, the check valve 17 operates. Opening allows hydraulic oil to pass through both cylinders. Since the throttle mechanism is formed by press-fitting the bush into the communication passage, a load is applied to the communication passage in the hydraulic oil passing state, and a pushing-down force acts on the piston. Therefore, even if the piston is about to stagnate just before reaching the lower limit due to sliding resistance or viscous resistance,
It is forced down to the lower limit.

The throttling mechanism of this embodiment is constructed by press-fitting a bush into the communication passage. However, the throttling degree can be adjusted by a variable valve, and the throttling degree can be made larger on the drive side than on the driven side. It is also possible to make corrections in order from the drive side, or to open the throttle when the piston reaches the lower limit so that hydraulic oil can pass without resistance. The diaphragm may be provided at any position in the communication path by any means. Further, although the embedded type lift has been described in the embodiment, it can be applied to a two-column type, a four-column type, etc. of a floor type,
The structure of the check valve is also changed as appropriate. After the communication passage is opened, a pressure difference is generated by the throttling action and the piston is forcibly pushed down.The idea of the present invention is that in a lift that does not have a forced lowering function, the piston is leveled at the upper limit of the cylinder. Add that it can be applied to the technology.

[0013]

According to the present invention, when the lift-down is carried out, at the same time as confirming that the tuning is carried out, if there is a tuning deviation, it is automatically and surely corrected. You can use it with confidence.

[Brief description of drawings]

1A and 1B are explanatory views showing a cylinder mechanism of an embedded lift in which a method for correcting a tuning deviation in a cylinder mechanism according to the present invention is implemented.

FIG. 2 is a hydraulic circuit diagram of an embedded lift that implements a method for correcting a synchronization deviation in a cylinder mechanism according to the present invention.

FIG. 3 is an explanatory diagram of a conventional example.

[Explanation of symbols]

1 ・ ・ Drive side cylinder mechanism, 2 ・ ・ Driven side cylinder mechanism, 1a, 2a ・ ・ Upper cylinder chamber, 1b, 2b ・ ・ Lower cylinder chamber, 3 ・ ・ Piston rod, 4 ・ ・ Pit, 5 ・
・ Drive on plate, 6 ・ ・ Piston, 7 ・ ・ Communication oil passage, 8 ・ ・ Feed oil passage, 9 ・ ・ Return oil passage, 10 ・ ・ Switching valve, 11 ・ ・ Pump, 12 ・ ・ Oil tank,
13 ・ ・ Pressurizing passage, 14 ・ ・ Returning passage, 15 ・ ・ Communication passage, 1
5a ... Horizontal hole, 15b ... Vertical hole, 16, 17 ... Check valve, 17a. Ball, 18 ... Bushing, 19 ... Pin holder, 20 ... Push-up pin.

Claims (1)

Claim: What is claimed is: 1. A plurality of double-acting cylinder mechanisms for raising and lowering a vehicle support are connected in series, and each cylinder mechanism is synchronously moved upward by supply of operating hydraulic pressure, or hydraulic oil. In a vehicle maintenance lift that forcibly lowers the piston by the reverse flow of, a communication passage that connects both cylinder chambers to the piston is provided, and a valve that opens at the lower limit position is provided in the communication passage. Even if the valve is opened by intentionally restricting the passage, a pressure difference is generated between both cylinder chambers, and the piston is reliably pushed down to the lower limit position by the continuous pushing down force. How to fix.