JP2008286306A - Power unit for lifting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power unit used for a lifting device which makes a wheelchair or the like ascend and descend to avoid a sudden ascent, descent and stop of a platform, to relax an impact given to a passenger in a wheelchair or the like on the platform, and to improve safety and reliability. <P>SOLUTION: The power unit is used for the lifting device which drives the platform for up-and-down movement between a descent position and a position on a vehicle floor surface by rotating a parallel link by a double-acting hydraulic cylinder 20. The power unit has a hydraulic circuit and a sensor means. The hydraulic circuit has first, second, and third electromagnetic switching valves B1, B2, B3, first and second throttle valves 71, 72, and a float control valve FC. The sensor means detects that the platform has reached a point close to the descent position and a point close to the position on the vehicle floor surface. For a section from the descent position of the platform to its proximity point and a section from the position on the vehicle floor surface to its proximity point, it is so configured that the first and the second electromagnetic switching valves B1, B2 are turned off so as to reduce the flow rate of the operating fluid with the throttle valves. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a power unit for a lifting device that is used in a lifting device for mounting and unloading a wheelchair, a carriage or other cargo mounted on a vehicle.

  As an elevating device for mounting and unloading a wheelchair or the like mounted on a vehicle, a device shown in the following Patent Document 1 proposed by the present applicant is known.

JP, 2001-55078, A This conventional device can raise and lower a raising / lowering platform between a landing position and a position on a vehicle floor (elevated position) such as a van type car by rotating a parallel link, In particular, it has a structure suitable for raising and lowering a wheelchair or the like.

  By the way, when using the above-mentioned conventional device for getting on and off a wheelchair, it avoids shocks such as sudden rise, sudden drop and sudden stop of the elevator platform to the wheelchair passenger, and does not give the passenger anxiety, ensuring safety and reliability. It is desired to improve it further.

  In view of the above points, the present invention can be used in a lifting device used to lift and lower a wheelchair and the like, avoiding a sudden rise, sudden drop and sudden stop of the lifting platform, and mitigating the impact on the wheelchair passengers on the lifting platform. Then, it aims at providing the power unit for lifting devices which aimed at the improvement of safety and reliability.

  Other objects and novel features of the present invention will be clarified in embodiments described later.

In order to achieve the above object, an aspect of the present invention provides a lifting / lowering device used for a lifting / lowering device that drives a lifting / lowering platform between a lowered position and a position on a vehicle floor by rotating a parallel link with a double-acting hydraulic cylinder. A power unit for the device,
A hydraulic circuit having first, second and third electromagnetic switching valves (B1, B2, B3), first and second throttle valves, and a float control valve;
An oil tank,
A hydraulic pump that sucks up the hydraulic oil in the oil tank and supplies the hydraulic oil to the double-acting hydraulic cylinder through the hydraulic circuit;
An electric motor that rotationally drives the hydraulic pump is provided in the outer case,
Between the hydraulic pump and a lowering drive port connected to the double-acting hydraulic cylinder, the third electromagnetic switching valve (B3), the first electromagnetic switching valve (B1), and the first electromagnetic switching valve are connected. The throttle valve's parallel connection is connected in series,
Between the hydraulic pump and the ascending drive port connected to the double-acting hydraulic cylinder, the third electromagnetic switching valve (B3), the second electromagnetic switching valve (B2), and the second electromagnetic switching valve are connected. The throttle valve's parallel connection is connected in series,
The first and second electromagnetic switching valves (B1, B2) are switched by sensor means for detecting that the elevating platform has reached the proximity point to the lowered position and the proximity point to the position on the vehicle floor. Done,
The first and second electromagnetic switching valves are turned off in the lowering position of the elevating platform and the section to the proximity point and in the section of the elevating platform on the vehicle floor surface and the proximity point. It is said.

  In the lifting device power unit, in the lowering operation of the lifting platform, the hydraulic pump is driven by the electric motor from the position on the vehicle floor until the parallel link is in a vertical state, and the third solenoid valve and The configuration may be such that hydraulic fluid is sent out from the descending drive port through the first throttle valve.

  During the period in which the lifting platform is lowered by its own weight, the float control valve causes the hydraulic oil to flow back to the oil tank at a substantially constant flow rate regardless of the load of the lifting platform until reaching the proximity point to the lowered position. May be.

  In the ascending operation of the elevating platform, the hydraulic pump is driven by the electric motor from the lowered position until the parallel link is in a vertical state, and hydraulic oil is sent from the ascending drive port through the third electromagnetic valve. It may be configured to.

  The sensor means may detect the inclination of the double-acting hydraulic cylinder or parallel link.

  According to the power unit for a lifting device according to the present invention, when used in a lifting device used for lifting and lowering a wheelchair or the like, it avoids sudden rise, sudden drop and sudden stop of the lifting platform and gives it to a wheelchair passenger or the like on the lifting platform. The impact can be mitigated, and as a result, safety and reliability can be improved.

  Hereinafter, as a best mode for carrying out the present invention, an embodiment of a power unit for a lifting device will be described with reference to the drawings.

  FIG. 1 shows an elevating device power unit, and FIGS. 2 and 3 show an elevating device in which the elevating platform is driven up and down by the elevating device power unit.

  The lifting device power unit PU shown in FIG. 1 sucks up the oil tank 61 and the hydraulic oil in the oil tank 61, and will be described later with reference to FIGS. 2 and 3 through the downward driving port P1 or the upward driving port P2 of the hydraulic circuit. A hydraulic pump P that supplies hydraulic oil to the double-acting hydraulic cylinder 20 of the lifting device, an electric motor M that drives the pump P, and opens when the discharge side of the pump P exceeds a certain pressure. A relief valve (safety valve) 62 for returning to the inside, first to fourth electromagnetic switching valves B1 to B4, and first and second throttle valves 71 connected in parallel to the first and second electromagnetic switching valves B1, B2. 72, a float control valve (constant flow valve) FC, and a check valve 73 connected in parallel thereto are provided in an exterior case (power unit case) 75.

  Further, each of the above components constituting the hydraulic circuit other than the oil tank 61 is housed in an inner case 76 inside the outer case 75, and the hydraulic pump P and the lower drive side oil supply port 201 of the double acting hydraulic cylinder 20 are stored. The third electromagnetic switching valve B3 and a parallel connection of the first electromagnetic switching valve B1 and the first throttle valve 71 are connected in series between the lowering drive port P1 connected to the first driving valve P1. Between the hydraulic pump P and the ascending drive port P2 connected to the ascending drive side oil supply port 202 of the double acting hydraulic cylinder 20, there are a third electromagnetic switching valve B3, a fourth electromagnetic switching valve B4, and a float control valve. The parallel connection of the FC and the check valve 73 and the parallel connection of the second electromagnetic switching valve B2 and the second throttle valve 72 are connected in series. The first and second electromagnetic switching valves B1 and B2 are switched by sensor means 80 provided on the lifting device side, which will be described later with reference to FIGS. There are two downward driving ports P1 and two upward driving ports P2. This is because two double-acting hydraulic cylinders 20 are provided on the left and right sides of the lifting device.

  FIGS. 2 and 3 show examples of the lifting device in which the lifting platform 30 is driven up and down by the lifting device power unit PU shown in FIG. In these drawings, reference numeral 1 denotes a van-type vehicle (box-type vehicle), and a main body frame 2 is erected and fixed on a rear floor surface 1a close to a rear surface opening of the vehicle body of the van-type vehicle. A main arm 3 and a sub arm 4 that constitute a substantially parallel link are pivotally attached (rotatably mounted) to the main body frame 2. That is, one end of the main arm 3 is pivotally attached to the main body frame 2 by the pin 3a, and one end of the sub arm 4 is pivotally attached by the pin 4a. A stay arm 5 is pivotally attached to the other end of the main arm 3 and the sub arm 4 by pins 3b and 4b, and a platform holder 10 is fixed to the lower end of the stay arm 5. Further, a double-acting hydraulic cylinder 20 for driving up and down is connected between the pins 4a and 3b. Accordingly, when hydraulic oil is supplied to the ascending drive side oil supply port 202 of the double-acting hydraulic cylinder 20 and the double-acting hydraulic cylinder 20 is contracted, the platform holder 10 is in the vehicle floor surface position (ascending position) in FIG. When hydraulic oil is supplied to the lower drive side oil supply port 201 of the double-acting hydraulic cylinder 20 and the double-acting hydraulic cylinder 20 is extended, the platform holder 10 and the lifting platform 30 that moves up and down integrally with the platform holder 10 are shown in FIG. It will be in the lowered position (landing state).

  On the platform holder 10, an elevating platform 30 is slidably (slidable) in the front-rear direction. The platform holder 10 has a structure that supports both side surfaces of the lifting platform 30, and a plurality of rollers 11 that are opposed to the both side surfaces of the lifting platform 30 are pivotally supported, and a substantially U-shaped cross-section rail 31 that engages with the rollers 11. Constitutes side portions on both sides of the platform 30.

  Further, the front and rear drive of the platform 30 is performed by winding a toothed belt (timing belt) 32 having both ends fixed to the front and rear of the platform 30 around a drive belt wheel 13 that is rotationally driven by the electric motor 12 as shown in FIG. Do by. The electric motor 12 is fixed to the platform holder 10, and driven belt wheels 14, 15 are pivotally supported on the platform holder 10 before and after the driving belt wheel 13. The elevating platform 30 can be stored up to the retract limit position (position retracted into the vehicle compartment) of FIG.

  As shown in FIGS. 2 and 3, at the front edge of the elevating platform 30 (here, the right side of FIG. 2 is the front side of the platform), the front side car stop device 40 that holds the front side car stop plate 41 in an upright state and a down state. Is provided. At the rear edge of the platform holder 10, a rear car stop device 50 that holds the rear car stop plate 51 in an upright state and a down state is provided.

  As shown in the enlarged portion of FIG. 2, the sensor means 80 for detecting the raising / lowering state of the raising / lowering platform 30 is provided on the mounting base of the double-acting hydraulic cylinder 20. That is, the pin 4 a is fixed to the mounting member 203 fixed to the main body of the double acting hydraulic cylinder 20, and the pin 4 a is rotatable with respect to the main body frame 2. A magnetic metal plate 81 is fixed to the pin 4 a, and a magnetic sensor 85 is fixed to the main body frame 2 at a position that can face the magnetic metal plate 81. The magnetic metal plate 81 has, for example, a fan shape, the section from the lowered position (landing state) to the proximity point thereof, and the proximity point from the position on the vehicle floor (the main arm 3 and the sub arm 4 are phantom lines in FIG. 2). When it is in the section up to the position where the descent force in the landing direction is generated by the weight of the platform in a state where it stands up substantially vertically as in (X), the magnetic sensor 85 and the magnetic metal plate 81 are in close proximity to each other, In other sections, the magnetic sensor 85 is positioned away from the magnetic metal plate 81.

  Next, the operation of the embodiment will be described in the case where the lifting device of FIGS. 2 and 3 is driven. As shown in FIG. 2, when the double-acting hydraulic cylinder 20 for raising and lowering drive is in a contracted state, the platform holder 10 is in the raised position where it is drawn into the passenger compartment of the van-type vehicle 1, and the platform 30 is further moved to the position shown in FIG. ), The platform 30 can also be retracted into the passenger compartment. The retracting operation of the platform 30 can be performed by rotating the driving belt wheel 13 counterclockwise by the electric motor 12 of FIG. 4 and causing the toothed belt 32 to travel in the left direction.

  Conversely, by rotating the drive belt wheel 13 to the right, the platform 30 at the pull-in limit position in FIG. 2 (a) can be moved to the forward position (the position on the vehicle floor that can be raised and lowered) in FIG. 2 (b). it can. 2B, the front vehicle stop plate 41 connected to the front edge of the platform 30 is in the upright locked state, and the rear vehicle stop plate 51 connected to the rear edge of the platform holder 10 is also in the locked state. ing.

  When the platform 30 is set to the lowered position (landing state) from the forward movement state (position on the vehicle floor surface) of the platform 30 in FIG. 2 (b), the proximity point (the main arm 3 and the sub arm 4 are located from the position on the vehicle floor surface). In the section from the imaginary line (X) to the position where the landing force is generated by the weight of the platform in a state of standing substantially vertically as shown in the imaginary line (X), the electric motor M in the lifting device power unit PU in FIG. The hydraulic oil is operated and the hydraulic oil is sent from the hydraulic pump P to the descending drive port P1. At this time, the magnetic sensor 85 of the sensor means 80 shown in the enlarged view of FIG. 2 is in close proximity to the magnetic metal plate 85, the first and second electromagnetic switching valves B1 and B2 are off (closed), The hydraulic oil is supplied to the downward drive side oil supply port 201 through the 3 electromagnetic switching valve B3, the first throttle valve 71, and the downward drive port P1, and the second throttle valve 72, the float control valve FC, The hydraulic oil returns to the oil tank 61 through the path of the 4 electromagnetic switching valve B4 and the third electromagnetic switching valve B3. Since the first and second throttle valves 71 and 72 are inserted in the hydraulic oil supply and return paths, the lowering operation of the platform 30 starts slowly.

  A platform 30 is a proximity point at a position on the vehicle floor surface (a position where a descent force in the landing direction is generated by the weight of the platform in a state where the main arm 3 and the sub arm 4 stand up substantially vertically as shown in FIG. After passing, the magnetic sensor 85 is located away from the magnetic metal plate 85, the electric motor M is turned off, and the platform 30 descends in the landing direction due to the weight of the platform 30. At this time, since the magnetic sensor 85 is located away from the magnetic metal plate 85, the first and second electromagnetic switching valves B1, B2 are turned on (opened), and the flow rate of the first and second throttle valves 71, 72 is reduced. Since there is no restriction, the platform 30 descends faster. However, since the return of the hydraulic oil is limited to a constant flow rate regardless of the load on the platform 30 by the float control valve FC, even if the load on the platform 30 is heavy, the descending speed does not become too fast.

  When reaching the position before the lifting platform 30 is landed (when the main arm 3 and the sub arm 4 are at the imaginary line (Y) in FIG. 3) of the descending position, the magnetic sensor 85 again returns to the magnetic metal plate 85. The first and second electromagnetic switching valves B1 and B2 are turned off (closed) and the flow rate is throttled by the first and second throttle valves 71 and 72, so that the platform 30 is slow. And land as shown in FIG. 3 (becomes a lowered position). It is possible to get on and off the platform 30 such as the wheelchair 70 in the landing state.

  When the platform 30 is set to the position on the vehicle floor surface of FIG. 2B from the lowered position (landing state) of the platform 30 in FIG. 3, the electric motor M in the lifting device power unit PU in FIG. The hydraulic oil is sent from the pump P to the ascending drive port P2. At this time, in the section from the lowered position of the platform 30 to the proximity point to the lowered position, the magnetic sensor 85 of the sensor means 80 is in close proximity to the magnetic metal plate 85, so the first and second electromagnetic switching valves B1, B2 is OFF (closed), and hydraulic fluid is supplied to the ascending drive side oil supply port 202 through the third solenoid directional valve B3, the fourth solenoid directional valve B4, the float control valve FC, the second throttle valve 72, and the ascending drive port P2. The hydraulic oil returns to the oil tank 61 through the path of the first throttle valve 71 and the third electromagnetic switching valve B3 from the descending drive side oil supply port 201. Since the first and second throttle valves 71 and 72 are inserted into the return and supply path of the hydraulic oil, the ascending operation of the platform 30 starts slowly.

  After passing the section from the lowered position to the close point to the lowered position, the magnetic sensor 85 is moved away from the magnetic metal plate 85, so that the first and second electromagnetic switching valves B1, B2 are turned on (opened). Since the flow rate is not reduced by the first and second throttle valves 71 and 72, the platform 30 is quickly raised.

  At a proximity point in front of the position on the vehicle floor (position where the main arm 3 and the sub arm 4 rise substantially vertically as shown in the imaginary line (X) in FIG. 2 and the landing force generates a descent force in the landing direction). After the platform 30 arrives, the magnetic sensor 85 again comes close to and faces the magnetic metal plate 85, the first and second electromagnetic switching valves B1 and B2 are turned off (closed), and the first and second throttles are reached. When the flow rate is reduced by the valves 71 and 72, the platform 30 moves slowly and reaches the position on the vehicle floor surface of FIG.

  The fourth electromagnetic switching valve B4 is provided to stop the platform 30 at an arbitrary position.

  According to this embodiment, the following effects can be obtained.

(1) When used in a lifting device used for raising and lowering a wheelchair, etc., the lowering position (landing state) of the lifting platform 30 and the section to its proximity point, and the position of the platform 30 on the vehicle floor and the section to its proximity point In order to reduce the flow rate by inserting the first and second throttle valves 71 and 72 in the hydraulic oil supply to the double-acting hydraulic cylinder 20 and the hydraulic oil return path, the rapid increase, sudden decrease and sudden stop of the platform 30 are avoided. Further, it is possible to mitigate the impact on the wheelchair passengers on the platform, and to improve safety and reliability.

(2) When the platform 30 is lowered, the float control valve FC is inserted into the hydraulic oil return path from the hydraulic cylinder 20, so that the platform 30 is lowered at a constant flow rate regardless of the load on the platform 30. Can do. Variations in descent speed associated with load fluctuations on the platform 30 can be avoided.

(3) Other than the sensor means can be stored compactly in the exterior case (power unit case) 75.

  Although the sensor means 80 detects the inclination of the double-acting hydraulic cylinder 20 with the magnetic metal plate 81 and the magnetic sensor 85 and indirectly recognizes the state (position) of the lifting platform 30, the parallel link (the main arm 3, It may be configured to detect the inclination of one of the sub arms 4, and a limit switch or the like may be used instead of the magnetic sensor.

  Although the embodiments of the present invention have been described above, it will be obvious to those skilled in the art that the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the claims.

1 is a hydraulic circuit diagram showing an embodiment of a power unit for a lifting device according to the present invention. It is an example of the raising / lowering device to which the said power unit for raising / lowering devices is applied, Comprising: It is a side view when a raising / lowering platform exists in a vehicle floor surface position. In the said raising / lowering apparatus, it is a side view which shows the descent | fall position (landing state) of a raising / lowering platform. It is a side view which shows the mechanism part which drives a raising / lowering platform to the front-back direction.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Van type car 1a Floor surface 2 Main body frame 3 Main arm 4 Sub arm 5 Stay arm 10 Platform holder 20 Double acting hydraulic cylinder 30 Lifting platform 61 Oil tank 71, 72 Throttle valve 73 Check valve 75 Exterior case 80 Sensor means 201 Lowering drive Side oil supply port 202 Ascending drive side oil supply port B1 to B4 Solenoid switching valve FC Float control valve M Electric motor P Hydraulic pump P1 Down drive port P2 Up drive port PU Lift unit power unit

Claims (5)

A power unit for a lifting device used in a lifting device that rotates a parallel link with a double-acting hydraulic cylinder to drive the lifting platform between a lowered position and a position on the vehicle floor surface,
A hydraulic circuit having first, second and third electromagnetic switching valves (B1, B2, B3), first and second throttle valves, and a float control valve;
An oil tank,
A hydraulic pump that sucks up the hydraulic oil in the oil tank and supplies the hydraulic oil to the double-acting hydraulic cylinder through the hydraulic circuit;
An electric motor that rotationally drives the hydraulic pump is provided in the outer case,
Between the hydraulic pump and a lowering drive port connected to the double-acting hydraulic cylinder, the third electromagnetic switching valve (B3), the first electromagnetic switching valve (B1), and the first electromagnetic switching valve are connected. The throttle valve's parallel connection is connected in series,
Between the hydraulic pump and the ascending drive port connected to the double-acting hydraulic cylinder, the third electromagnetic switching valve (B3), the second electromagnetic switching valve (B2), and the second electromagnetic switching valve are connected. The throttle valve's parallel connection is connected in series,
The first and second electromagnetic switching valves (B1, B2) are switched by sensor means for detecting that the elevating platform has reached the proximity point to the lowered position and the proximity point to the position on the vehicle floor. Done,
The first and second electromagnetic switching valves are turned off in the lowering position of the elevating platform and the section to the proximity point and in the section of the elevating platform on the vehicle floor surface and the proximity point. Power unit for lifting device.   In the lowering operation of the elevating platform, the hydraulic pump is driven by the electric motor from the position on the vehicle floor surface until the parallel link is in a vertical state to pass through the third electromagnetic valve and the first throttle valve. The power unit for a lifting device according to claim 1, wherein hydraulic oil is sent out from the lowering drive port.   The hydraulic oil is recirculated to the oil tank at a substantially constant flow rate regardless of the load of the lifting platform by the float control valve until the lifting platform is lowered by its own weight until reaching the proximity point to the lowered position. Or the power unit for raising and lowering devices of 2.   In the ascending operation of the elevating platform, the hydraulic pump is driven by the electric motor from the lowered position until the parallel link is in a vertical state, and hydraulic oil is sent from the ascending drive port through the third electromagnetic valve. The power unit for an elevating device according to claim 1, 2, or 3.   The power unit for a lifting device according to claim 1, 2, 3, or 4, wherein the sensor means detects an inclination of the double-acting hydraulic cylinder or parallel link.

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