JPH05132266A - Hydraulic elevator and method for lowering the same - Google Patents

Abstract

PURPOSE: To operate an elevator cage safely and lower it without generating shocks by providing a circuit means for opening a check valve between a pump means and a cylinder when a fluid pressure in the former becomes approximately equal to a fluid pressure in the latter and opening the check valve when the cage is required to be lowered. CONSTITUTION: When a cage 12 is stopped at a landing, a truncated conic section 72 of a check valve 36 sits on a peripheral portion 78 of a central bore 42, hydraulic oil 26 is prevented from flowing from a hydraulic cylinder 16 to a tank 24 via a line 54, a valve 18, and a line 28, and the cage 12 is held at the landing. When the cage 12 is required to be lowered, switching to a first circuit 98 by exciting a solenoid valve 38, the first fluid pressure F1 communicates with an opening end 84 of a cylinder 80. When the first fluid pressure F1 pressing a piston 82 becomes larger than the sum of the second fluid pressure F2 and the spring force, the truncated conic section 72 separates from the peripheral portion 78 and the check valve 36 is opened.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to hydraulic elevators, and more particularly to hydraulic elevators driven by variable speed motors.

[0002]

2. Description of the Related Art A hydraulic elevator is a cab
And a plunger attached to the cab directly or via a rope hooking structure, and a cylinder for accommodating the plunger. The hydraulic fluid is pushed into the cylinder by a constant speed motor that drives a constant displacement pump.

This type of hydraulic elevator requires valves to control cab speed and lower the elevator during acceleration and leveling. The valve wastes energy as it drains excess hydraulic fluid flow when controlling elevator motion. Also, the valve is noisy and has relatively poor controllability. Some hydraulic elevators use variable speed pumps and motors. This type of hydraulic elevator drives a plunger and a cab mounted on the plunger upward and downward by pushing hydraulic oil into the cylinder and discharging the hydraulic oil from the cylinder. Variable speed pumps and motors are known to reduce control problems and significantly reduce the number of valves. However, valves are still needed to keep the elevator on the landing.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a hydraulic elevator driven by a variable speed pump and a motor, the hydraulic elevator having a valve that enables safe operation of the elevator. It is in. Another object of the present invention is to provide a valve that allows the elevator cab to be lowered without shocking passengers in the elevator.

Yet another object of the present invention is to provide a valve that produces an elevator control signal that safely initiates elevator up and down.

[0006]

SUMMARY OF THE INVENTION According to the present invention, a valve for communicating variable fluid pressure in a hydraulic elevator prior to moving the elevator cab either upwards or downwards. A valve is provided in which the fluid pressure on the pump side of the is balanced with the fluid pressure on the cylinder side of the valve.

The valve of the present invention is located in the line that allows fluid to pass between the variable speed pump and the cylinder. Fluid pressure from the pump acts on one side of the valve. The fluid pressure in the cylinder acts on the other side of the valve. On the pump side of the valve, another circuit (this circuit may be controlled by a solenoid) allows another pump until the total fluid pressure acting on the pump side of the valve overcomes the fluid pressure acting on the cylinder side of the valve. Direct fluid pressure to the back of the valve to open it.

Before opening the valve, the fluid pressure on the pump side of the valve and the fluid pressure on the cylinder side of the valve are balanced to gently and safely lower the elevator without shocking passengers in the cab. Can be started. Due to the large pressure drop between the cylinder side of the valve and the pump side, the cab is lowered rapidly when the fluid pressure is not balanced. Sudden descent is difficult to control, shocks passengers and is unsafe.

Also, the elevator will not descend unless the motor drives the pump at least initially. This feature minimizes the likelihood that the elevator will descend without controlling the motor. The above and other objects, features and advantages of the present invention will become apparent from the following detailed description of the best mode for carrying out the invention shown in the accompanying drawings.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An elevator system 10 includes an elevator car 12, a plunger 14, a hydraulic cylinder 16 and a valve 1.
8 and a conventional variable speed / reversible motor 20 and pump 2
2 and. The pump 22 and the motor 20 are arranged in a tank 24 filled with hydraulic oil 26. As is known in the art, motor 20 drives pump 22 to drive an elevator (elevator car).
Fluid pressure to raise and lower 12 (fluid pressure force,
"FPF") is generated. As is known in the art, elevator system 10 may be provided with a pressure relief valve and a manual down valve (not shown).

First fluid pressure of pump 22 (first FPF)
F ₁ is in communication between valve 18 and pump 22 via line 28. Second fluid pressure (second FPF) F
₂ includes a valve 18 and a hydraulic cylinder 16 via a line 30.
And communicates with. A drain pressure line 32 is provided between the valve 18 and the tank 24. The valve valve 18 includes a housing 34, a check valve 36, a solenoid valve 38, and a biasing assembly 40.

Housing The housing 34 has a central bore 42 which includes a cylinder port 44, a pump port 46, a first solenoid port 48, a second solenoid port 50,
And to the drain port 52. As shown,
The cylinder port 44 receives the hydraulic oil 26 and the second fluid pressure F.
₂ is communicated with the left side of the bore 42 via the line 30. The pump port 46 allows the hydraulic fluid 26 and the first fluid pressure F ₁ to pass through the line 28 to the central region 56 of the bore 42.
Is in communication with. The first solenoid port 48 has a first
Fluid pressure F ₁ is applied to solenoid valve 38 via line 58.
The second solenoid port 50 communicates the first fluid pressure F ₁ from the solenoid valve 38 to the biasing assembly 40 via line 60. The drain port 52 communicates with the tank pressure (that is, the drain pressure) via the drain pressure line 32.

The housing 34 has a first region 62 of greater diameter than the central bore 42.
Contains a check valve 36 and a flange 64 extending radially inward into the central bore 42 and having a through hole formed therein, which acts as a spring seat. The housing 34 also includes a second region 66 having a larger diameter than the central bore 42, and the second region 66 houses the biasing assembly 40. A conventional position sensor 68 extends through the housing 34 in the first region 62. The housing 34 has an end cover 70 that is attached to the housing 34 by conventional means such as screws or bolts (not shown).

The check valve 36 has a frusto-conical portion 72, a disc-shaped spring seat 74, and a rod 76 for fixedly connecting the frusto-conical portion 72 and the spring seat 74. The rod 76 extends through a central portion (central region) 56 of the bore 42 and an opening (through hole) formed by the flange 64. A spring 79 is arranged around the rod 76, and the spring 79 abuts on the spring seat 74 and the flange 64. The frusto-conical portion 72 abuts the position sensor 68 when seated on the peripheral edge 78 of the central bore 42.

The biasing assembly biases the assembly 40 includes a cylinder 80 disposed in the second region 66, a piston 82 disposed in the cylinder 80 in
And have. Cylinder 80 has an open first end 84 that receives a first fluid pressure F ₁ from line 60 and a closed second end 86 with a bore 88 through which piston 82 passes. The piston 82 includes a head 90 fitted in a cylinder 80 and a shaft 9 extending through a hole 88.
2 and. The shaft 92 is in contact with the spring seat 74 of the check valve 36. An opening 94 is provided in the cylinder 80 on the shaft side of the piston head 90, and the opening 94 communicates with the drain port 52. For ease of manufacture, the piston head 92 and shaft 92 can be formed as separate pieces.

Solenoid Valve The solenoid valve 38 is controlled by a computer 96, as is commonly known. The solenoid valve 38 connects the hydraulic oil 26 from the line 58 to the line 60, and
First circuit 9 for communicating fluid pressure F ₁ with biasing assembly 40
8 and the hydraulic oil 26 through the line 60 and the line 102.
Circuit 1 for connecting the cylinder 80 to the tank 24
00 and. To use the first circuit 98, the solenoid valve 38 must be energized by the computer 96. If the solenoid valve 38 is not energized, i.e. in case of a power failure, the second circuit 100 is used. When the second circuit 100 is used, the first fluid pressure F ₁ cannot communicate with the biasing assembly 40.

When the operating cab (elevator car) 12 is at rest on a landing (not shown), the frustoconical portion 7 of the check valve 36 is shown.
2 is seated on the peripheral edge of the central bore 42, so that the hydraulic oil 26 is transferred from the hydraulic cylinder 16 via the line 30 to the valve 1
It is prevented from flowing through 8 to the tank 24 via the line 28, thus keeping the cab 12 on the landing.

When it is desired to move the cab 12 to the lower landing, the computer 96 energizes the solenoid valve 38 to switch to the first circuit 98. As a result, the first fluid pressure F ₁ is reduced to the central bore 42, the first solenoid port 4
8, the line 58, the line 60, and the second solenoid port 50 communicate with the open end 84 of the cylinder 80, and further communicate with the piston head 90 in the cylinder 80. The piston 82 is pressed by the first fluid pressure F ₁ , which causes the spring seat 74 (the spring seat 74 is a rod 76).
Connected to the frusto-conical portion 72 via). Computer 96 also energizes motor 20 to increase first fluid pressure F ₁ .

The frusto-conical portion 72 has a first fluid pressure F acting on the frusto-conical portion 72 and the piston head 90.
₁ total of up to overcome the spring force of the second fluid pressure F ₂ and the spring 79, is maintained in engaged seat to the periphery 78 of the central bore 42. When the total of the first fluid pressure F ₁ becomes larger than the total of the second fluid pressure F ₂ and the spring force, the truncated conical portion 72 and the peripheral portion 78 separate from each other and the check valve 36 is opened. .. When the first fluid pressure F ₁ and the second fluid pressure F ₂ are approximately equal, the check valve 36 is essentially open.

Once the valve 18 is opened, the cab 1
A warning is issued from the position sensor 68 to the computer 96 that the variable speed motor 20 should be controlled according to the selected speed profile for lowering 2 to the next landing. With such a velocity profile, the motor 20 is gradually decelerated to rotate in the reverse direction to control the descending acceleration (energy is generated), and then, when the cab 12 approaches the desired landing, the rotation is reversed again. Then, the descending speed of the cab 12 is slowed down.

In an emergency such as a power failure, or in the cab 1
If you want to keep 2 stopped at the landing,
The solenoid valve 38 is deenergized (deenergized) by the motor 96.
It As a result, the second circuit 100 of the solenoid valve 38
When activated, the first fluid pressure F ₁Is the piston head 90
Will be shut off. Actuation acting on the piston head 90
The oil 26 is supplied to the second solenoid port 50, the line 60, the
Discharge to drain via 2 circuits 100 and line 102
To be done. First fluid pressure F acting on the check valve 36 ₁Sum of
Is the second fluid pressure F acting on the check valve 36.₂And spring force
Is less than the sum of and. Therefore, the second fluid pressure F₂
And the spring force of the return spring 79 centers the frustoconical portion 72.
It acts to sit on the peripheral edge 78 of the bore 42,
Stops the flow of hydraulic oil 26 from the hydraulic cylinder 16.
Then, the descent of the cab 12 is stopped.

When it is desired to raise the cab 12,
The motor 20 is controlled by the computer 96, and the check valve 36
First fluid pressure F acting on₁Raise. First fluid pressure
Force F ₁Force due to the second fluid pressure F₂Force and spring force
When larger, the check valve 36 pops open. position
The sensor 68 detects that the first fluid pressure F₁And the second fluid pressure F₂When
A signal that the
Input to the computer 96. Computer 96
The desired as known in the art.
Control the motor 20 according to the ascending profile.

Prior to opening valve 18, pump 22 and valve 1
By balancing the fluid pressures acting on both sides of the eight cylinders 80, the elevator descent can be started gently and safely without shocking passengers in the cab 12. If the fluid pressure is not balanced, the cab 12 will be lowered rapidly due to the large pressure drop between the cylinder and pump sides of the valve 18. Sudden descent is difficult to control, shocks passengers and is unsafe. Further, when the motor 20 does not drive the pump 22 at least initially, the cab 12 does not descend. If the motor 20 does not transmit a certain amount of torque to the pump 22, the fluid pressure in the pump 22 will not be great enough to open the check valve 36. This feature minimizes the probability that the elevator will descend without controlling the braking of the motor 20.

While the best mode embodiment of the present invention has been illustrated and described above, those skilled in the art will appreciate various modifications, omissions and omissions to the illustrated embodiment without departing from the spirit and scope of the invention. Additions could be made. Those skilled in the art will appreciate that the valve of the present invention may be used with or without a variable speed motor and constant displacement pump, a low speed motor and variable displacement pump, or other means. It will be appreciated that various fluid pressures of will work.

[Brief description of drawings]

FIG. 1 is a schematic configuration view showing in cross section a part of an embodiment of a valve of the present invention used in combination with a variable speed motor and a pump of a hydraulic elevator.

[Explanation of symbols]

 10 Elevator System 12 Elevator Car (Car Room, Cab) 14 Plunger 16 Hydraulic Cylinder 18 Valve 20 Motor 22 Pump 24 Tank 26 Hydraulic Oil 28 Line 30 Line 32 Drain Pressure Line 34 Housing 36 Check Valve 38 Solenoid Valve 40 Energizing Assembly 42 Central Bore 44 Cylinder Port 46 Pump Port 48 First Solenoid Port 50 Second Solenoid Port 52 Drain Port 56 Central Bore Central Region 58 Line 60 Line 62 First Region 64 Flange 66 Second Region 68 Position Sensor 70 End Cover 72 Sliding Frusto-conical portion 74 spring seat 76 rod 78 center bore peripheral edge 80 cylinder 82 piston 84 cylinder open first end 86 cylinder closed second end 88 hole 90 piston head 92 piston The second circuit 102 lines of the first circuit 100 solenoid valve shaft 94 aperture 96 computer 98 solenoid valve

 ─────────────────────────────────────────────────── ———————————————————————————————————————————————————————————————————————————————— — 02002 Amherst Village Park 190

Claims (7)

[Claims] 1. In a hydraulic elevator, a cab, a plunger attached to the cab, a cylinder for allowing the plunger to move linearly, a pump means for communicating a variable fluid pressure to the cylinder, and a pump means. And a valve for communicating fluid pressure between the cylinder and the cylinder, the valve preventing the fluid pressure from flowing between the pump means and the cylinder, and the pump means. When the fluid pressure in the cylinder becomes substantially equal to the fluid pressure in the cylinder, the fluid pressure acts on the check valve, and circuit means for pushing and opening the check valve against the fluid pressure in the cylinder is provided. A hydraulic elevator characterized in that when there is no condition and it is desired to lower the cab, the circuit means presses the check valve to open it. 2. The circuit means comprises a solenoid valve which directs fluid pressure toward the check valve when energized and depressurizes fluid pressure to the check valve. The hydraulic elevator according to claim 1, characterized in that the orientation is stopped. 3. The circuit means comprises second circuit means for preventing fluid pressure of the pump from being transmitted to the valve to maintain the cab in a landing. The hydraulic elevator according to claim 1, wherein the check valve is not opened when desired or when an emergency condition exists. 4. In a hydraulic elevator, a cab, a plunger attached to the cab, a cylinder for allowing the plunger to move linearly, a pump for communicating fluid pressure to the cylinder, and a driving force for the pump. And a valve for transmitting the fluid pressure from the pump to the cylinder, and the valve allows the fluid to flow between the pump and the cylinder, that is, the fluid pressure is transmitted. And a first circuit means for causing a fluid pressure of the pump to act on the check valve and forcing the check valve to open against the fluid pressure of a cylinder. When there is no emergency condition and it is desired to lower the cab, the first circuit means presses the check valve to open it, and the fluid pressure of the pump is applied to the check valve. Further comprising second circuit means to stop acting and allow the fluid pressure in the cylinder to close the check valve, in case an emergency situation exists and it is desired to keep the cab in place. Is a hydraulic elevator characterized in that the second circuit means presses the check valve to close it. 5. A solenoid valve having the first circuit and the second circuit incorporated therein is further provided, and when the solenoid valve is energized, the first circuit is operated and the solenoid valve is not energized. The hydraulic elevator according to claim 1, wherein the second circuit sometimes operates. 6. A cab, a plunger attached to the cab, a cylinder for allowing the plunger to move linearly, and a first valve for controlling fluid flow to and from the cylinder. A method for lowering a hydraulic elevator having a variable speed motor and a pump, wherein fluid pressure (FPF) of the pump is transmitted from the pump to a second valve, and when it is desired to lower the cab, the second Energizing a valve to transmit the fluid pressure of the pump to the first valve to cause the opening of the first valve; and when the fluid pressure of the pump is equal to or higher than the fluid pressure of the cylinder, the first A method for lowering a hydraulic elevator, characterized by opening a valve. 7. A cab, a plunger attached to the cab, a cylinder for allowing the plunger to move linearly, and a first valve for controlling the flow of fluids to and from the cylinder. A method for lowering a hydraulic elevator having a variable speed motor and a pump, wherein fluid pressure (FPF) of the pump is transmitted from the pump to a second valve, and when it is desired to lower the cab, the second Urging a valve to transmit the fluid pressure of the pump to the first valve to open the first valve, and to open the first valve when the fluid pressure of the pump becomes higher than the fluid pressure of the cylinder, or When there is an emergency condition or when it is desired to stop the downward movement of the cab, the second valve is deenergized to stop transmitting the fluid pressure of the pump, When the pressure becomes higher than the fluid pressure of the pump, hydraulic elevators, characterized in that for closing the first valve.