JPH0818772B2 - Method of operating clamp for lifting device and hydraulic circuit used for it - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lifting device for raising or lowering a cage on which a person or luggage is placed by operating a hydraulic cylinder through a wire rope, and a clamping clamp for holding the cage at a predetermined stop position. Is related to the operation of.

[0002]

2. Description of the Related Art As a lifting device for lifting and lowering a cage through a wire rope by means of a hydraulic cylinder as described above, a sheep (2) is attached to the upper end of a hydraulic cylinder (1) fixed vertically as shown in FIG. ) Is provided with a pulley, and one end is fixed and the other end is loaded with luggage etc.
It is general that the wire rope (4) connecting (3) is hung on the sheep (2). In such an elevating device, the cage is raised and lowered to stop it at a predetermined position, and the floor of the cage is aligned with the floor for loading and unloading luggage and the cage door is opened. After loading and unloading, close the door and lift / lower again.

However, when the load in the cage changes due to the loading and unloading of cargo in the cage as described above, the wire rope that supports the load is stretched and the hydraulic oil in the hydraulic cylinder and the hydraulic system is compressed.・ The stop position of the cage will move due to expansion or other reasons. Such movement of the stop position adversely affects loading and unloading of luggage and riding comfort.

Conventionally, therefore, in such a lifting device, as shown in FIG. 3, rails (5) for vertically fixing a building or the like are provided on both sides of a cage that moves up and down, and one cage (3 ) Is a friction pad as shown in FIG.
A holding clamp (7) having (6) facing each other is attached at a position where the rail (5) is held. When the cage (3) reaches the stop position, this operation method activates the clamping hydraulic cylinder (8) of the clamping clamp (7) to clamp both sides of the rail (5) with the friction pad (6). By pressing, the cage is fixed at its stop position. With such a sandwiching clamp, it is possible to eliminate fluctuations in the stop position of the cage when loading and unloading luggage and the like. In addition to the clamping clamp shown in FIG. 4, a friction pad (6) for clamping the rail (5) is provided at the tip as shown in FIG. 5, and the other end is constantly pressed inward by a compression spring (10). And a pair of scissor-shaped arms (9) having opposite protrusions (11) (11) inside the other end, and sliding while contacting the protrusions (11) (11) of the arm (9). There is also a structure having a clamp hydraulic cylinder (8) having a wedge-shaped tip actuating piece (12) for expanding the end from the inside. As for the relationship between the rail and the clamping clamp, there is also a structure in which the rail is provided on the cage side and the clamping clamp is provided on the fixed side of a building or the like.

[0005]

However, as described above, in the structure in which the holding position of the cage is held by the holding clamp, the holding clamp is operated to hold and fix the cage position, and loading and unloading of luggage etc. from the cage is performed. After closing the door and opening the clamping clamp, the load in the cage has already fluctuated. Was given. Furthermore, in order to ensure the safety of the cage when a rapid displacement of the cage is detected, a safety device called a so-called safety catcher that urgently fixes the cage to the rail or the like may be activated.

[0006]

As a result of various studies in view of the above, the present invention has been made, and as a result of various studies, a method of operating a clamping clamp in which a cage is prevented from being rapidly displaced even after loading and unloading of loads and the like of a lifting device. And the hydraulic circuit used for this.

[0007] That is, the operating method of the present invention, in the stopping position of the cage in the lifting device for raising or lowering the cage through the wire rope by the hydraulic cylinder,
When the cage starts to move up and down, the clamping clamp consisting of a friction pad that secures the rail and rails provided in the up-and-down direction that guides the cage up and down is gradually opened, and then rapidly. It is characterized by opening.

Further, the hydraulic circuit of the present invention is characterized in that, in the stopping position of the cage in the lifting device for raising or lowering the cage by the hydraulic cylinder through the wire rope,
In the hydraulic circuit of the clamping clamp which is operated by a hydraulic cylinder for clamping, which is composed of a friction pad fixing the rail provided in the up-and-down direction for guiding the ascent and descent of the cage, the above-mentioned when the clamping clamp is opened. A throttle valve is provided in a communication passage between the hydraulic cylinder and an oil tank in which the hydraulic oil returns.

[0009]

Next, an embodiment of the present invention will be described with reference to the holding clamp having the structure shown in FIG. As shown in Fig. 1, the main part of the hydraulic circuit of the hydraulic cylinder for clamping is the solenoid valve.
Hydraulic cylinder for clamping through (20) and solenoid valve (21)
The passage through which hydraulic oil flows into the pressure chamber (22) of (8) and the solenoid valve (2
Return chamber (23) of hydraulic cylinder (8) for clamping through (0)
And a passage for the hydraulic oil to flow into the solenoid valve (21).
A throttle valve (24) and a check valve (25) are provided in parallel with the.

The operating method of the clamp hydraulic cylinder (8) is as follows. That is, when the cage reaches a certain stop position, the clamp hydraulic cylinder (8) operates the clamping clamp to hold the cage at the stop position. At this time, when the pressure in the pressurizing chamber (22) of the cylinder (8) is schematically shown, both the solenoid valve (20) and the solenoid valve (21) are ON.
Since the hydraulic pressure is applied to the pressurizing chamber (22) of the cylinder (8) from the solenoid valve (20) through the check valve (25), the plunger (26) is pushed to the forward limit. The pressure in the cage pressurizing chamber (22) is constant because the pressure of the hydraulic source is applied as it is (state shown by A in FIG. 2).

After that, the door is opened and the luggage or the like is placed on the cage, or is lowered and the door is closed (point P in FIG. 2).
The solenoid valve (20) is turned off by this closed signal. By doing so, the hydraulic pressure is added to the return chamber (23) of the clamping hydraulic cylinder (8), so that the plunger (26) in the pressurizing chamber (22)
The hydraulic oil pressed by the oil passage (26)
However, since the solenoid valve (21) remains ON at this time, the passage through this solenoid valve (21) is closed, and the check valve (25) passage is also closed. Eventually, this hydraulic oil will gradually pass through the throttle valve (24).
This throttle valve (24) allows the hydraulic cylinder for clamping (8)
The pressure in the pressurizing chamber (22) does not suddenly decrease, but is slowly reduced as shown by B in FIG. Therefore, since the tip actuating piece (12) retreats slightly, even if the load inside the cage has already changed as described above, the pad surface and the rail surface slide on the contact surface between the friction pad of the clamping clamp and the rail. However, since both of them move slowly, the cage does not rise and fall rapidly as in the past.

The slow movement of the cage is stopped when the load of the cage and the load in the cage and the hydraulic pressure in the wire rope and the hydraulic circuit are balanced.
And the solenoid valve (21) is turned off by this signal (point Q in Fig. 2).
As a result, the solenoid valve (20) remains off and hydraulic pressure is being applied to the return chamber (23) side, so the hydraulic fluid in the pressurizing chamber (22) opens the solenoid valve (21). Since the oil quickly returns to the oil tank (27) through the passage, the pressure in the pressurizing chamber (22) sharply drops as shown in FIG. 2C. Then, the tip actuating piece (12) of the cylinder (8) is rapidly retracted, so that the clamping clamp is also rapidly released. Then, after confirming the release of the clamping clamp (point R in FIG. 2), the raising or lowering of the cage is started.

[0013]

As described above, according to the present invention, in the lifting device, the cage rapidly moves up and down after the door is closed, so that the luggage and the person in the cage are shocked.
Since this sudden shock is eliminated, the ride comfort is comfortable, and since the safety catcher, which is a safety device, is not activated, there are remarkable effects such as smooth driving.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of a hydraulic circuit of the present invention.

FIG. 2 is an explanatory view showing an embodiment of the operating method of the present invention.

FIG. 3 is an explanatory view showing an elevating device to which the present invention is directed.

FIG. 4 is a cross-sectional view of essential parts showing a holding clamp of the lifting device.

FIG. 5 is a side view of an essential part showing another holding clamp of the lifting device.

[Explanation of symbols]

 1 Hydraulic Cylinder 2 Sheep 3 Cage 4 Wire Rope 5 Rail 6 Friction Pad 7 Clamping Clamp 8 Clamping Hydraulic Cylinder 9 Arm 10 Compression Spring 11 Protrusion 12 Tip Actuating Piece 20, 21 Solenoid Valve 22 Pressurizing Chamber 23 Return Chamber 24 Throttle Valve 25 Check valve 27 Oil tank

Claims (2)

[Claims] 1. A rail provided in a vertical direction for guiding the raising / lowering of the cage and the cage at a stop position of the cage in a lifting device that raises or lowers the cage via a wire rope by a hydraulic cylinder. A method of operating a clamping clamp of an elevating device, characterized in that a clamping clamp made of a friction pad for fixing a clamp is first gradually opened when the cage starts to move up and down, and then rapidly opened. 2. A rail vertically provided to guide the raising and lowering of the cage at the stopping position of the cage in a lifting device that raises or lowers the cage via a wire rope by a hydraulic cylinder, and the cage. In the hydraulic circuit of the clamping clamp that consists of a friction pad that fixes the
A hydraulic circuit for a clamping clamp of an elevating device, characterized in that a throttle valve is provided in a communication passage between the hydraulic cylinder and an oil tank in which hydraulic oil returns when the clamping clamp is opened.