JP2014065380A - Load receiving table lifting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a load receiving table lifting device capable of stable sliding even when the load pedestal fluctuates.SOLUTION: A load receiving table lifting device comprises a load receiving table liftable/lowerable and slidable in the lower part of a load-carrying platform, a lifting/lowering drive part lifting and lowering the load receiving table, a slide drive part sliding the load receiving table, a height detection part detecting a height position in the lifting and lowering of the load receiving table, a slide detection part detecting a predetermined slide position in a sliding operation of the load receiving table and a control part driving the lifting/lowering drive part or the slide drive part. In an operation of sliding the load receiving table, switching to a lifting/lowering operation through output signals from the height detection part is controlled on the basis of output signals from the slide detection part.

Description

  The present invention relates to a load receiving table lifting device that can be stored below a loading platform, and more particularly, to a load receiving table lifting device in which the load receiving table is pulled out from the stored state to the rear of the vehicle.

  In the load receiving platform lifting device stored below the loading platform, a slide rail that guides the sliding member is attached to a chassis frame that extends in the vehicle longitudinal direction, and the sliding member moves back and forth along the rail (for example, Patent Document 1). . A link member having an arm that pivots up and down is connected to the slide member, and a load receiving platform is supported at the tip of the arm. When the slide member is slid forward, the load receiving platform is housed below the loading platform and the vehicle is in a retracted state in which the vehicle can travel. On the other hand, when the load receiving table lifting device is used for loading and unloading work, the load receiving table is slid rearward of the vehicle, and the load receiving table is moved up and down by the link member.

  A detection device such as a proximity sensor that detects that the load receiving table has reached a predetermined position is used for switching between the slide operation and the lifting operation between the storage position of the load receiving table and the loading / unloading work position. For example, a slide operation is performed to the rear of the vehicle, and when it is detected that the rear end position of the slide has been reached, the descent operation is performed as it is and the load receiving platform is grounded. In other words, while the operator commands the pull-out operation, the detection device detects the position and posture of the load receiving platform and outputs the signal, so that the operation is switched between the slide operation and the lift operation. .

Japanese Patent Application Laid-Open No. 2005-233892

  However, in the sliding operation of the load receiving table, the folded load receiving table does not remain in its folded state. For this reason, the load receiving platform swings slightly during the sliding operation. There is a risk that surrounding workers and the like may be uneasy about the performance of the load receiving platform lifting / lowering device due to the rocking state and the generated sound.

  Specifically, the height position of the load receiving table in the sliding operation is grasped by detecting the folding angle of the load receiving table. That is, whether or not the sliding operation is possible is determined based on whether or not a predetermined folding angle is detected. Therefore, when the folding portion of the load receiving platform swings and the folding angle of the load receiving stand changes due to frictional resistance generated between the slide member and other members such as the slide rail during the sliding operation, the folding angle is related. The detection signal is switched.

  In particular, when the trigger for the control that starts the lifting / lowering operation is simply switching the detection signal of the folding angle, the lifting / lowering operation is unexpectedly started even during the sliding operation. This change in the folding angle is a single occurrence that occurs unexpectedly, such as the frictional resistance mentioned above, and the folding angle instantaneously returns to the previous value (normal value). If it happens intermittently, the raising / lowering operation is repeated although it is minute. As a result, the cargo cradle is also slid while repeating the raising / lowering operation slightly, and noise is also generated due to hydraulic noise and mechanical noise based on continuous switching between the raising / lowering operation and the sliding operation. In general, the slide operation and the lifting operation of the load receiving table are performed in such a manner that an operator continuously outputs a pull-in operation or a pull-out command (continuously presses the button), so once the swinging operation occurs, the load receiving table Ascending / descending operation and sliding operation also facilitate the swinging of the load receiving table folding part and the generation of the noise.

  The present invention has been made in view of these points, and an object of the present invention is to provide a load receiving table lifting / lowering device capable of performing a stable slide operation even when the folding portion of the load receiving table swings.

  In response to the above-described problem, the load receiving table lifting device of the present invention has the following configuration.

  First, the load receiving platform lifting device is capable of moving up and down with respect to the vehicle and slidable below the loading platform of the vehicle, a lifting drive unit that moves the load receiving table up and down, and a slide drive unit that slides the load receiving table. A height detection unit that detects the height position of the lifting operation of the load receiving table, a slide detection unit that detects a predetermined slide position in the sliding operation of the load receiving table, and a control unit that drives the lifting drive unit or the slide driving unit. Is provided. And this control part is set so that the switching to the raising / lowering operation | movement by the output signal of a height detection part may be controlled based on the output signal of a slide detection part with respect to the receiving stand which carries out a slide operation | movement. The “slide detection unit” detects a predetermined position in a range where the slide operation is performed, and includes, for example, a unit that detects a front end position or a rear end position of the slide range.

  Accordingly, even if the height detection unit responds unexpectedly at least during the slide operation of the load receiving table, the elevation drive unit is prevented from being driven only by the signal of the responded height detection unit. Can do. That is, the slide operation of the load receiving table is not hindered during the slide operation.

  The “predetermined slide position” is preferably at least one of a slide start position and a slide end position within a range in which a slide operation is set. Thereby, the drive of the raising / lowering drive part in the middle of a slide can be prevented reliably. The “slide start position” and “slide end position” can be set as appropriate depending on the type of vehicle, the size of the load receiving platform, and the like.

Next, the slide detection unit uses an ON signal or an OFF signal as an output signal, and the switching to the lifting operation by the output signal of the height detection unit is performed based on switching from one to the other in the ON signal or the OFF signal. It is desirable to set as follows.
In particular, it is preferable that the slide operation is a slide operation toward the rear of the vehicle, and the elevating operation is a descending operation.

  The drive of the slide drive unit is set to be driven by either the first height position detection signal or the second height position detection signal by the height detection unit, It is set to be driven by either a first slide position or a second slide position detection signal by the slide detection unit.

  With the configuration of the present invention, while the operation command for the slide operation is output from the operation unit, the slide operation is continued even if the type of the detection signal of the height detection unit is changed during the slide operation. That is, the raising / lowering operation is not started during the sliding operation. Therefore, the load receiving table does not rattle up and down, noise generation is prevented, and stable sliding operation is performed.

It is a side view of the load receiving table raising / lowering apparatus which concerns on embodiment of this invention. 1 is a hydraulic circuit diagram according to an embodiment of the present invention. It is a schematic diagram which shows the operation part and control part which concern on embodiment of this invention. It is a side view which shows the drawer | drawing-out operation | movement of the cargo receiving stand raising / lowering apparatus which concerns on embodiment of this invention. It is a time chart figure of the drawer operation of the load receiving table raising / lowering apparatus which concerns on embodiment of this invention. It is a flowchart figure of operation | movement control of the drawer operation | movement of the cargo receiving stand raising / lowering apparatus which concerns on embodiment of this invention. It is a side view which shows the drawing-in operation | movement of the load receiving table raising / lowering apparatus which concerns on embodiment of this invention. It is a time chart figure of the drawing-in operation | movement of the load receiving table raising / lowering apparatus which concerns on embodiment of this invention.

An example of an embodiment of the present invention will be described with reference to the drawings.
1. Configuration of lifting platform

  FIG. 1 is a side view of a load receiving platform lifting apparatus 100 that moves up and down at the rear of the vehicle, with the left side in the figure as the front of the vehicle and the right side as the rear of the vehicle. The vehicle is supported by a pair of left and right chassis frames 2 in which a loading platform 1 extends in the front-rear direction, and a slide rail 3 extending in the front-rear direction is attached below the chassis frame 2. The load receiving platform elevating device 100 includes a slide member 4 that can slide in the front-rear direction using the slide rail 3 as a guide member, a slide cylinder that slides the slide member 4 back and forth (see FIG. 2), and the slide member 4. The link member 5 whose one end is pivotably supported up and down, the lift cylinder 55 that pivotally drives the link member 5 up and down, and the load receiving base that is supported by the other end of the link member 5 and can be folded. 6 is provided. Further, the load receiving table elevating device 100 includes a control unit (see FIG. 3) 30 that controls the sliding operation and the lifting operation of the load receiving table 6, and a detection unit (FIG. 3) that outputs a signal that triggers drive control by the control unit. Reference) 31a to 31d are provided.

  The slide member 4 is configured to be slidable between a state located at the rear portion of the slide rail 3 as shown in FIG. 1A and a state located at the front portion of the slide rail 3 as shown in FIG. Has been. The slide member 4 is engaged and supported by a pair of left and right slide rails 3. A connecting member (not shown) extending in the vehicle width direction is installed on the left and right slide members 4, and a slide cylinder is attached to the connecting member. The slide member 4 is driven by expansion and contraction of the slide cylinder. The slide cylinder is a set of two, and each telescopic rod is configured in the opposite direction. These slide members 4 and slide cylinders constitute a slide drive unit.

  The link member 5 includes a tilt arm 52 that is pivotally supported on the first support bracket 51 via a connecting shaft 5a. On the upper side of the tilt arm 52, the base end of the lift arm 53 is connected to the support member 54 via the tilt arm 52 and the first support bracket 51. A load receiving platform 6 is rotatably connected to the tip of the lift arm 53. A lift cylinder 55 is disposed below the lift arm 53, one end of which is pivotally supported by the tilt arm 52 and the other end is pivotally supported by the lift arm 53. The lift arm 53 is vertically rotated by the expansion and contraction of the lift cylinder 55. That is, the link member 5 and the lift cylinder 55 provided on the link member 5 constitute an elevation drive unit.

The load receiving platform 6 has a base 61, an intermediate portion 62, and a tip portion 63. The base portion 61 is supported by the lift arm 53, the intermediate portion 62 can be folded with respect to the base portion 61, and the tip portion 63 can be folded with respect to the intermediate portion 62 (can be folded in three). When the loading platform lifting device 100 is not used, the loading platform 6 is folded and stored under the loading platform 1 as shown in FIG. In addition, the storage state refers to a state where the vehicle is stored in the lower part of the loading platform 1 as shown in FIG. .
2. Next, a description will be given of the hydraulic drive device that contributes to the slide operation or the lift operation of the load receiving platform 6. In this embodiment, the hydraulic drive device 10 of FIG. 2 is used.
The hydraulic drive device 10 includes an electric motor M, a hydraulic pump P driven by the electric motor M, and an oil tank T provided on the suction side of the hydraulic pump.

  Further, the hydraulic drive device 10 includes a pressure oil supply passage 12 that supplies pressure oil in the discharge passage 11 of the hydraulic pump P to the lift cylinder 55, and a control valve SOL1 for raising operation that communicates or blocks the flow of the pressure oil supply passage 12. The pressure oil return path 13 branched from the upstream side of the ascending operation control valve SOL1 in the pressure oil supply path 12 and connected to the oil tank T, and the descending operation control valve SOL2 communicating or blocking the flow of the pressure oil return path 13 A flow control valve 13a downstream of the lowering control valve SOL2 and a main relief valve R1 for defining the maximum value of the discharge pressure of the hydraulic pump P are provided. The ascending operation control valve SOL1 and the descending operation control valve SOL2 constitute a lift cylinder control valve that controls the flow of pressure oil to the lift cylinder 55.

  Further, the hydraulic drive device 10 is provided with a first pressure oil supply path 14 that branches from the discharge path 11 of the hydraulic pump P and connects to the rod side of the slide cylinder 45, and the first pressure oil supply path 14 includes The flow of the second pressure oil supply path 15 and the second pressure oil supply path 15 branched from the throttle valve 14a and the check valve 14b and the first pressure oil supply path 14 and connected to the bottom side of the slide cylinder 45 is communicated or cut off. The flow of the pressure oil return path 16 and the pressure oil return path 16 branched from the second pressure oil supply path 15 and connected to the oil tank T on the downstream side of the drawer operation control valve SOL3. A pull-in operation control valve SOL4 that communicates or shuts off is provided.

A bypass branched from the discharge passage 11 and connected to the pressure oil return passage 16 at a position downstream of the main relief valve R1 and upstream of the pull-in operation control valve SOL3 or the pull-out operation control valve SOL4. A path 17 is provided. The bypass passage 17 is provided with a sub relief valve R2 and a switching valve SOL5. The switching valve SOL5 receives the drive signal and switches to a communication position or a shut-off position, and communicates or shuts off the flow of pressure oil to the sub relief valve R2 by the switching. The switching valve SOL5 may be provided on the downstream side of the sub relief valve R2. The relief pressure of the sub relief valve R2 is set to 6MP, for example, and is set lower than the main relief valve R1 (for example, 20MP). When the switching valve SOL5 is switched to the communication position and connected to the discharge passage 11, the maximum value of the pressure oil in the discharge passage 11 is set to a value lower than that of the main relief valve R1.
The hydraulic drive apparatus 10 having such a configuration is controlled using the operation unit 20 shown in FIG. 3 and a control unit 30 provided in the vehicle.

  An operator grips and operates the operation unit 20, and an operation signal is output from the operation unit 20 to the control unit 30. The control unit 30 receives the operation signal and drives the load receiving table elevating device 100 (slide cylinder 45, lift cylinder 55, control valves SOL1, SOL2,...).

  The operation unit 20 includes buttons 21a to 21c and a transmission unit 22 that creates serial data of the on or off states of the buttons 21a to 21c and transmits the serial data as a radio signal. The buttons 21a to 21c are respectively an ascending button 21a, a descending button 21b, and a power button 21c with respect to the cargo receiving platform 6. Although the operation unit 20 of the present embodiment is a wireless operation unit, it may be a wired operation unit connected to the vehicle side (or power unit).

The control unit 30 receives an output signal from a detection unit that detects the operation of the load receiving platform 6 and the slide member 4, and an output signal of the ascending button 21a or the descending button 21b operated by the operator. The control unit 30 stores an input unit 32 that inputs detection signals from the sensors 31a to 31d serving as detection units, a reception unit 33 that receives an output signal from the operation unit 20, and a control program, a control threshold value, and the like. A storage unit 34, a calculation unit 35 that executes calculation processing based on a control program stored in the storage unit 34 and generates a command signal for the expansion / contraction operation of the slide cylinder 45 or the lift cylinder 55, and a command from the calculation unit 35 And an output unit 36 that outputs signals to the control valves SOL1 to SOL5, the conductor relay C, and the like.
3. Features of the detector

  Each sensor 31a-31d used as the above-mentioned detection part is provided in the vehicle side. The slide rail 3 is provided with a rear end sensor 31a, an intermediate sensor 31b, and a hydraulic pressure sensor 31c, and a folding sensor 31d is provided at a hinge connecting the base 61 and the intermediate part 62 of the load receiving platform 6. For example, proximity sensors and limit buttons can be used for these sensors 31a to 31d.

  The rear end sensor 31a is a detection unit that detects that the slide member 4 has slid to a predetermined position on the vehicle rear side. The slide rail 3 is provided with a stopper (not shown) that restricts the sliding of the slide member 4, and is configured such that when the slide member 4 comes into contact with this stopper, the vehicle cannot be further slid rearward. That is, the predetermined position detected by the rear end sensor 31a is the position at which the load receiving platform 6 is at the rearmost end in the slideable range. The rear end sensor 31a is always in a detection state (ON state) when the cargo receiving platform 6 is located at a predetermined position detected along the vehicle longitudinal direction.

  The intermediate sensor 31b is detection means for detecting that the cargo receiving platform 6 has been slid to a midway position in front of the vehicle. The midway position is a position that is near the front of the vehicle but does not reach the foremost end of the slidable range. The intermediate sensor 31b is in a non-detection state (off state) until it reaches the midway position from the vehicle rear side, and is always in a detection state (on state) when it is located forward along the vehicle longitudinal direction from the midway position. It is set to become.

  The hydraulic sensor 31 c is a detection unit that detects that the folded load receiving platform 6 is lifted and pressed against the slide rail 3. As the lift cylinder 55 extends, the load receiving platform 6 rises, and a pad (not shown) provided in a region of the load receiving platform 6 facing the slide rail 3 is pressed against the slide rail 3. This pad is fixed to the back surface of the intermediate portion 62 of the load receiving platform 6 (the surface facing the ground when the load receiving platform 6 is deployed). When the pad is pressed against the slide rail 3, the pressure in the discharge path 11 of the hydraulic control unit 10 increases, so that a threshold value is set for the detection value of the hydraulic sensor 31 c, and when this threshold is reached, the load receiving platform 6 is placed on the slide rail 3. Judged to have touched

  The folding sensor 31 d is a detecting unit that detects how much the intermediate portion 62 of the load receiving platform 6 is folded with respect to the base portion 61. The load receiving platform 6 rises from the ground contact state and is pulled into the front of the vehicle at a predetermined height. The folding angle of the load receiving platform 6 changes with the rise from the ground contact position. When the folding sensor 31d detects that the angle of the load receiving platform 6 is an angle for performing the pull-in operation toward the front of the vehicle, the pull-in operation is started. As the folding sensor 31d, an angle sensor, a proximity sensor, or the like that detects an angle of the intermediate portion 62 with respect to the base portion 61 of the load receiving platform 6 can be used. In the folding sensor 31d of the present embodiment, when the intermediate portion 62 with respect to the base portion 61 reaches the folding angle at which the sliding operation can be performed, the detection state (ON state) is set, and the angle is different from the angle. Is in a non-detection state (off state).

Therefore, the rear end sensor 31a and the intermediate sensor 31b serve as a slide detection unit that detects the position of the slide operation of the load receiving platform 6. Further, the hydraulic pressure sensor 31c and the folding sensor 31d serve as a height detection unit that detects the position of the lifting / lowering operation of the load receiving platform 6.
4). Pull-out control from stored state

  Next, with reference to FIGS. 4 and 5, the pulling-out operation of the load receiving table lifting / lowering device 100 using the hydraulic drive device 10, the operation unit 20, and the control unit 30 described above will be described. FIG. 4 is a side view of the load receiving table lifting apparatus 100 showing the pulling operation, and FIG. 5 is a time chart showing operation commands to the operation unit 20 and the control unit 30 in the pulling operation.

  In the load receiving platform lifting / lowering apparatus 100 of the present embodiment, in the “drawing operation” from the state in which the load receiving platform 6 is folded and stored below the load receiving platform 1 (the vehicle travelable state) to the state in which the load receiving platform 6 contacts the ground. , “First drawer” operation (time T1 to T2), “first drop” operation (time T2 to T3), “second drawer” operation (time T3 to T4), “second drop” operation (time T4 to T4) T5) is performed in order. This embodiment is characterized by the control in the second pull-out operation.

  First, the first drawing operation is performed from the state of FIG. FIG. 4 (a) shows the receiving platform 6 in the retracted state. The first pull-out operation is an operation in which the stowage 6 in the retracted state is slid to the vehicle rear side of the arrow A1, and after the main switch of the control unit 3 is turned on (time T0), the operator This is performed by pressing the lowering button 21b of the operation unit 20 (time T1) in order to pull out the load receiving platform toward the rear side of the vehicle (see FIG. 5). When the lowering button 21b is pressed, the electric motor M is driven by energizing the conductor relay C, and the three control valves of the lowering operation control valve SOL2, the pulling operation control valve SOL3, and the pulling operation control valve SOL4 are simultaneously activated. The communication is switched to the communication state. The lift cylinder 55 is depressurized by bringing the lowering operation control valve SOL2 into a communicating state. In the retracted state, the load receiving platform 6 is held below the loading platform 1 through the extension operation of the lift cylinder 55, and at this time, the pressure oil is sealed in the pressure oil supply path 12. When the temperature rises and the pressure oil expands, the lift cylinder 55 unexpectedly expands, and the load receiving platform 6 rises and is pressed against the slide rail 3 with a larger pressure than the desired storage state. By releasing the sealed pressure oil, it is possible to suppress the frictional force of the load receiving table 3 against the slide rail 3 at the start of the first pulling operation, or to prevent the load receiving table 6 from being damaged. Further, by making the pull-in operation control valve SOL4 in a communicating state, it is possible to prevent noise from occurring at the start of the first pull-out operation. In the retracted state, the pressure oil is sealed in the first pressure oil supply passage 14, and not only the lowering operation control valve SOL2 is inserted, but the drawing operation control valve SOL4 is also inserted, Suppresses pressure oil from flowing out at a high pressure. As in the case of the lift cylinder 55, this suppression effect is particularly remarkable when it is affected by the expansion of pressure oil due to an increase in temperature.

  When the first pulling-out operation is completed (time T2), the intermediate sensor 31b is switched from the on state to the off state. The electric motor M is turned off by the switching of the intermediate sensor 31b as a trigger, the lowering operation control valve SOL2 is switched to the communication state, and the drawer operation control valve SOL3 is switched to the cutoff state. At this time, the folding sensor 31d is kept on. By these controls, the first lowering operation is performed in which the lift cylinder 55 contracts and the load receiving platform 6 descends. By the first lowering operation, the cargo receiving platform 6 is lowered from the “first height position” in FIG. 4A to the “second height position” in FIG. When the first lowering operation is started, as shown in FIG. 4B, the load receiving platform 6 is located at the “first slide position” moved by the length L1 from the front end position, and the first in the direction of the arrow A2 The intermediate portion 62 of the load receiving platform 6 is inclined with respect to the base portion 61 by the 1 lowering operation. When the load receiving platform 6 is lowered by the height H1, the folding angle of the load receiving platform 6 is also increased, the folding sensor 31d is switched to the OFF state, and the first lowering operation is completed. In addition, since the load receiving stand 6 is separated from the slide rail 3 by the first lowering operation, the hydraulic pressure sensor 31c is turned off.

  Next, the second drawing operation is started. With the input of the OFF signal of the folding sensor 31d as a trigger, the lowering control valve SOL2 is switched to the shut-off state, and the pull-out operation control valve SOL3 is switched to the communication state, and the electric motor M is driven. By these controls, the slide cylinder 45 is newly extended, and the load receiving platform 6 moves (slides) in the direction of arrow A3 as shown in FIG. In the present embodiment, the second pull-out operation starts from the position at which the load receiving platform 6 switches from the lowering operation to the pull-out operation due to the extension of the slide cylinder 45, and the “second slide position” as the slide end position is set as a predetermined value. The slide position is the end point. When the load receiving platform 6 moves to the second slide position, when the second pull-out operation is completed (time T4), the rear end sensor 31a is switched from the off state to the on state, and a switching detection output signal is input to the control unit 30. . With this switching detection as a trigger, the electric motor M is turned off, the lowering operation control valve SOL2 is switched to the communication state, and the drawing operation control valve SOL3 is switched to the cutoff state. And the goods receiving stand 6 descend | falls in the arrow A4 direction as it is. Thereafter, the cargo receiving platform 6 is brought into a grounded state as shown in FIG.

As shown in FIG. 4 (d), an operator manually unfolds the load receiving platform 6 bent into a "<" shape so that the load can be loaded. The unfolded load receiving platform 6 is moved up and down behind the vehicle and used for loading and unloading loads.
Of the above pulling operation and descending operation, the second pulling operation performs the following control.

  When the slide member 4 is affected by frictional resistance or the like generated when the slide member 3 slides on the slide rail 3, the intermediate portion 62 swings up and down with respect to the base portion 61 although it is minute. Due to the up and down swing, the detection of the folding sensor 31d may be switched from the off state to the on state in the middle of the second slide operation as indicated by a dotted line portion D1 in FIG. Regarding the second slide operation, the start of the operation is triggered by switching from the on signal to the off signal of the folding sensor 31d as described above. On the other hand, for the slide operation (in the middle of the slide operation), the trigger is set not to trigger the slide operation even when switching from the off signal to the on signal occurs. Therefore, it does not switch to the ON state indicated by the dotted line portion D2 (the control valve SOL2 for lowering operation is inserted), and continues to slide until the predetermined slide position (second slide position) detected by the rear end sensor 31a. Operation is performed.

  Specifically, this will be described with reference to the flowchart of FIG. In FIG. 6, the control in the second pull-out operation is mainly shown. During this control, the lowering button 21b is pressed.

  When the first lowering operation is performed until the folding sensor 31d switches from the on state to the off state (steps S1 and S2), the second pulling operation is started (step S3).

  In the second pull-out operation, the second pull-out operation is started when the load receiving platform 6 slides until the rear end sensor 31c is switched from the off state to the on state without the folding sensor 31d being switched on in the middle. (Steps S4 to S6).

  On the other hand, when the folding sensor 31d is switched on in the middle of the second pulling operation (step S4), the lowering operation control valve SOL2 and the pulling operation control valve SOL3 are set next to the slide operation being performed. By controlling as described above, it is determined whether or not to continue the slide operation.

  Regardless of the switching of the output signal of the folding sensor 31d that first occurs during the sliding operation, the shut-off state of the lowering operation control valve SOL2 is maintained (step S41). This is different from the control triggered by switching of the output signal of the folding sensor 31d at the start of the second slide operation (time T3). Next, it is confirmed whether the rear end sensor 31c is in an on state or an off state (step S42). If the rear end sensor 31c does not change and remains in the OFF state, it is determined that the slide operation is still in progress, and the lowering operation control valve SOL2 remains in the shut-off state (step S43). At this time, the pull-out operation control valve SOL3 may be in a communication state or a shut-off state. As a result, the second lowering operation of the cargo receiving platform 6 is not started, and only the second pulling operation is continued (step S3). When the folding sensor 31d is switched to the on state (step S4), if the rear end sensor 31c is also switched to the on state (step S42), the load receiving platform 6 reaches the slide rear end position (second slide position). It determines with having slid and transfers to 2nd descent | fall operation | movement (step S6). That is, in the present embodiment, switching from the second pulling operation to the second lowering operation is not controlled by switching the detection signal of the folding sensor 31d at the midway position where the second pulling operation is being performed. The detection signal of the rear end sensor 31 c is switched by being input to the control unit 30. As a result, even if the detection of the folding sensor 31d is switched from the off state to the on state during the second pull-out operation, the load receiving platform 6 is pulled out to a predetermined position where the rear end sensor 31c is switched from the off state to the on state. The second pulling-out operation is continued. By adopting such switching control from the second pull-out operation to the second lowering operation, the folding portion of the load receiving platform 6 swings up and down with respect to the base portion 61 like the intermediate portion 62 during the slide operation. However, the cargo receiving platform 6 is not moved up and down unnecessarily. Since the lifting operation of the load receiving platform 6 is prevented, the pressure oil is not switched excessively, and it is possible to prevent the sound accompanying the switching from being generated. In addition, it is possible to prevent the generation of mechanical noise accompanying the raising and lowering of the load receiving platform 6.

  In particular, in the second pull-out operation, the slide operation is performed at a position lower than that in the first pull-out operation. At this time, since the folding of the load receiving tray 6 is in a slightly opened state, the folding portion (intermediate portion 62) is likely to swing up and down as compared with a state in which the folding is not opened. Therefore, even if the detection signal of the folding sensor 31d is switched due to the swinging of the folding part, it is possible to prevent the lifting operation of the cargo receiving platform 6 itself from starting. Further, if the detection area is enlarged by enlarging the area of the detected part so that the detection signal of the folding sensor 31d does not switch even if a minute swing occurs in the folding part, Although it interferes with the interference and the workability of the operator, it is not preferable, but such a problem can be solved by the control as in this embodiment.

The control for continuously executing the sliding operation related to the second pulling-out operation described above is particularly “simple operability” in the load receiving platform elevating device 100 in which the operation control is performed based on the signal information of the plurality of sensors 31a to 31d. It has a great effect in that it does not hinder. Switching between the pulling-out operation and the lowering operation is performed at each position such as the first slide position by detecting the switching between the ON state and the OFF state of the plurality of sensors 31a to 31d. Therefore, if the operator simply keeps pressing the lowering button 21b, even if an unexpected swing occurs in the folding part of the load receiving table 6, the load receiving table sequentially moves from the first pulling-out operation to the second lowering operation. Stable operation can be performed.
5. Next, an operation for storing the pulled-out receiving platform 6 and its control will be described.

  After completing the loading and unloading of the luggage, the cargo receiving platform 6 is bent into a “<” shape to prepare for storage (preparation for pulling down the loading platform 1). The pull-in operation of the load receiving table lifting device 100 will be described with reference to FIGS. FIG. 7 is a side view of the load receiving platform lifting apparatus 100 showing the pull-in operation, and FIG. 8 is a time chart showing operation commands to the operation unit 20 and the control unit 30 in the pull-in operation.

  In the load receiving platform lifting apparatus 100 according to the present embodiment, in the “pull-in operation” from the ground receiving state to the state where the load receiving platform 6 is folded and stored below the loading platform 1 (vehicle travelable state), Time T6 to T7), “first pull-in” operation (time T7 to T8), “second rise” operation (time T8 to T9), and “second pull-in” operation (time T9 to T10) are sequentially performed.

  In the first ascending operation, when the operator presses the ascending button 21a of the operation unit 20 with the main switch turned on (time T6), the load receiving platform 6 ascends in the direction of arrow B1 shown in FIG. When the ascending button 21a is pressed, the electric relay M is energized to drive the electric motor M, and the ascending operation control valve SOL1 and the pulling operation control valve SOL3 are switched to the communication state (ON state). Since the pull-out operation control valve SOL3 is in a communicating state, the load receiving platform 6 is raised while the slide member 4 is in the rearmost position.

  By the first ascending operation, the load receiving platform 6 rises to the height H2, is folded to the state shown in FIG. 7B, and the folding sensor 31d detects that the intermediate portion 62 with respect to the base 61 of the load receiving platform 6 has a predetermined angle. A state is reached (time T7), the first ascending operation is completed, and the process proceeds to the first pull-in operation in the direction of arrow B2.

  In the first pull-in operation, the pull-out operation control valve SOL3 maintains the communication state. By maintaining the communication state of the control valve SOL3, it is possible to prevent noise from being generated when switching to the first pull-in operation.

  When the load receiving platform 6 moves forward by the length L2 by the first pull-in operation (the slide member 4 slides to a position separated from the foremost end of the slidable range by the length L1), the intermediate sensor 31b is turned on from the off state. The state is switched (time T8). When the detection of the intermediate sensor 31b is switched, the pull-in operation control valve SOL4 is continuously in communication for a predetermined time (time T8 to time T81), and the lowering operation control valve SOL2 and the pull-out operation control valve are in the same time. SOL3 is brought into a communication state. When the predetermined time has elapsed (time T81), the lift operation control valve SOL1 is in a communicating state, the lift cylinder 55 is extended, and the load receiving platform 6 is raised again. That is, switching from the first pull-in operation to the second ascending operation is performed based on switching of the detection signal of the intermediate sensor 31b. As a result, similarly to the second pulling-out operation, the sliding operation is continued even when the folding portion of the load receiving platform 6 swings and the detection signal of the folding destination 1d is switched, and the load receiving platform 6 is moved in the middle of the sliding operation. The raising / lowering operation is not started. Note that by setting a predetermined time after the detection by the intermediate sensor 31b as in the present embodiment, the pressure oil is released from the lift cylinder 55 and the slide cylinder 45, and the second rise from the first pull-in operation. Noise can also be prevented when switching operations.

  In the second ascending operation, the switching valve SOL5 is switched to the communication state (time T8). The switching valve SOL5 is in a communication state, and the relief pressure of the hydraulic drive device 10 is switched to a low relief pressure by the sub relief valve R2. That is, the relief pressure is set lower in the second raising operation than in the first raising operation.

  When the load receiving platform 6 is raised by the second raising operation, the pad provided on the load receiving platform 6 comes into contact with the hydraulic sensor 31c. Further, when the pad is strongly pressed against the hydraulic pressure sensor 31c and the hydraulic pressure sensor 31c enters the detection state (time T9), the control valve SOL1 for the upward movement is switched to the cutoff state, and the control valve SOL4 for the pulling operation is switched to the communication state. Be controlled. By these switching controls, the load receiving platform 6 is slid to the foremost end while being in contact with the slide rail 3 to be in the retracted state. The switching valve SOL5 is controlled to be switched to a non-communication state (off state) when a small time delay occurs (time T91) after the hydraulic pressure sensor 31c enters the detection state. This is to suppress the pressing force of the load receiving platform 6 against the slide rail 3 at the start of the second pull-in operation. When a time slightly longer than the slide time until the slide member 4 reaches the foremost position after the detection by the hydraulic sensor 31c (time T10), the electric motor M becomes non-driven and the pull-in operation control valve The SOL4 is controlled to be switched to the cutoff state. In this way, by setting the electric motor M and the pull-in operation control valve SOL4 to be controlled at time T10, the ascending button 21a is set between the time T9 and time T10 as shown in FIG. Even if released, the second pull-in operation is not stopped at that time, and is continued until the storage state is reached. Even if the ascending button 21a is continuously pressed, the second pull-in operation is performed until the retracted state.

The storing operation of the load receiving platform 6 is performed as described above, and the switching position between the pull-in operation and the raising operation is the first height position, the second height position, the first slide position, and Although it is the same position as the second slide position, it may be a different position.
6). Other

  As described above, the “switching from the second pulling operation to the second descending operation” and the “switching from the first pulling operation to the second ascending operation” cause switching of the detection signal of the folding sensor 31d, respectively. However, the configuration is not executed, and the configuration is executed by switching of the detection signal by the rear end sensor 31a or the intermediate sensor 31b. That is, since the trigger for switching control of the load receiving platform 6 from the sliding operation to the raising / lowering operation is the detection of switching of the slide detection unit instead of the height detection unit, “switching from the first pull-out operation to the first lowering operation” is performed. Can also be applied. Further, the present invention can be similarly applied even when the pulling-out operation and the pulling-in operation consist only of a single sliding operation and a lifting / lowering operation, or when the number of the sliding operations and the lifting / lowering operations is different between the pulling-out operation and the pulling-in operation.

  Further, regarding the detection of the on state or the off state of each of the sensors 31a to 31d, the folding sensor 31d is turned off even when the main switch is turned on in the opposite detection state, for example, the first pulling operation, and the second high The folding angle of the load receiving platform 6 when reaching the position (position where the first lowering operation is switched to the second pulling operation) may be detected and switched to the on state.

  INDUSTRIAL APPLICABILITY The present invention is useful for a load receiving platform lifting / lowering device housed under a vehicle loading platform that is pulled out by a sliding operation.

DESCRIPTION OF SYMBOLS 1 Loading platform 2 Chassis frame 3 Slide rail 4 Slide member 5 Link member 6 Loading platform 10 Hydraulic drive device 20 Operation part 30 Control part 31a Rear end sensor 31b Intermediate sensor 31c Hydraulic sensor 31d Folding sensor 45 Slide cylinder 55 Lift cylinder P Hydraulic pump T Oil tank M Electric motor 100 Loading platform lifting device

Claims (5)

A cradle that can move up and down relative to the vehicle and is slidable underneath the pallet
An elevating drive unit for elevating and lowering the load receiving table;
A slide driving unit for sliding the load receiving table;
A height detection unit for detecting the height position of the lifting operation of the load receiving table;
A slide detection unit for detecting a predetermined slide position in the slide operation of the load receiving table;
A control unit for driving the elevating drive unit or the slide drive unit;
With
The control unit is set to control the switching to the lifting / lowering operation by the output signal of the height detection unit based on the output signal of the slide detection unit with respect to the slide operation. Receiving platform lifting device. 2. The load receiving platform lifting apparatus according to claim 1, wherein the predetermined slide position is at least one of a slide start position and a slide end position within a range in which the slide operation is set. The slide detection unit uses an on signal or an off signal as an output signal,
The load receiving platform according to claim 1 or 2, wherein switching to the lifting operation by an output signal of the height detection unit is performed based on switching from one to the other of these on signals or off signals. lift device. The sliding operation is a sliding operation toward the rear of the vehicle,
The cargo receiving platform lifting apparatus according to claim 3, wherein the lifting operation is a lowering operation. The drive of the slide drive unit is set to be driven by either the first height position detection signal or the second height position detection signal by the height detection unit,
The drive of the said raising / lowering drive part is set so that it may drive with either the detection signal of the 1st slide position by the said slide detection part, or a 2nd slide position. Cradle receiving device lifting device according to the above.

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