JP2013237379A - Load receiving platform elevating/lowering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a load receiving platform elevating/lowering device capable of allowing a user to feel the unchanged draw-out performance, and to realize the excellent draw-out operation.SOLUTION: A load receiving platform elevating/lowering device includes a load receiving platform which is elevated/lowered with respect to a vehicle, and slidable below a cargo bed of the vehicle, an elevating/lowering driving mechanism for elevating/lowering the load receiving platform, a slide driving mechanism for sliding the load receiving platform, and an operation device for outputting the drive command of the elevating/lowering operation and the slide operation of the load receiving platform. The elevating/lowering drive mechanism and the slide drive mechanism are driven in the slide operation of the load receiving platform from the storage position to the predetermined position backward of the vehicle. The slide time from the output start by the operation device to the predetermined position of the load receiving platform is set so as to be substantially agreed with the drive command time of the slide drive mechanism by the output of the operation device.

Description

  The present invention relates to a load receiving platform lifting device that can be stored below a loading platform, and more particularly to a load receiving platform lifting device that performs a slide operation that is pulled out from a stored state toward the rear of a 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.

  The load receiving platform lifting / lowering device is provided with a regulating member so that the load receiving platform does not swing up and down in the retracted state (for example, Patent Document 2). Thereby, the member damage by the vertical swing of the load receiving table lifting device and the generation of noise due to the interference with other members are prevented.

  Next, when using the load receiving table lifting device, the restriction by the restriction member is released. The raising and lowering operation and the sliding operation of the load receiving table are performed by extending and contracting the hydraulic cylinder. In the retracted state, the pressure oil path of the lift cylinder that drives the lifting and lowering operation is blocked, so that when the temperature rises and the pressure oil expands, it is pressed against the slide rail from the desired retracted state. For this reason, a control has been proposed in which a lift cylinder is depressurized, and after the depressurization is completed, that is, after a predetermined time lag is provided, a control for outputting a slide operation command has been proposed (Patent Document 3). Is being worked on.

Japanese Patent Application Laid-Open No. 2005-233892 Japanese Patent No. 4310258 Japanese Patent No. 4769689

  However, if the time for pressure release is simply added before the loading platform is pulled out, the operation time will increase compared to the conventional case, and the operator may be worried about the performance degradation or the speed of work. There is a possibility of requesting shortening of operation time. In addition, if the control is based on a change in the external environment such as a rise in temperature, there may be a problem when the external environment is stable.

  With regard to the concerns about performance degradation and the desire to shorten the operation time, attention is paid to the point that the operator feels that the responsiveness has decreased as compared with the pulling operation of the conventional load receiving table lifting device. When a predetermined time lag is provided as in Patent Document 3, a slide operation is always performed after the pressure release operation of the lift cylinder even if the operator outputs a load receiving table pull-out command using an operation device such as a radio control. For this reason, an operator will feel that the responsiveness is falling compared with the conventional drawer | drawing-out operation | movement. Moreover, since the time until the pulling-out operation is completed becomes long, it becomes difficult to satisfy the user's request for quickness. In addition, the control valve provided in the slide drive mechanism and the lift drive mechanism has various performances depending on the type and size of the vehicle to which the load receiving table lift device is attached, so the time lag setting value is changed for each vehicle. This increases the manufacturing cost.

  In addition, as for a problem that may occur when the external environment is stabilized, attention is paid to interference with a regulating member that regulates the vertical swing of the load receiving platform. The restriction member is provided so as to function in accordance with the slide operation of the load receiving table, and the restriction release is also performed based on the slide operation (drawing operation). It is not always an external environment where the load receiving stand is pressed against the slide rail more strongly than the desired state due to temperature rise. On the other hand, the above-described regulating member is not configured to assume changes in the external environment. For this reason, if the lifting operation is performed after the lift cylinder has been depressurized with respect to the load receiving table stored in a desired state, the restricting member functions firmly, and the restricting member does not move well when the load receiving table is pulled out. There is a risk that it will not be released. In this case, noise is generated due to interference with the regulating member, and the regulating member or the receiving platform is damaged.

  The present invention has been made in view of these points, and an object of the present invention is to provide a load receiving platform lifting device that allows a user to feel the same pulling performance as before and to realize a good pulling operation.

  In the load receiving platform lifting apparatus of the present invention, the above-described problem can be solved by the following configuration.

  The load receiving platform lifting apparatus according to the present invention includes a load receiving platform that can move up and down with respect to a vehicle and that can slide below the vehicle loading platform, a lifting drive mechanism that moves the load receiving platform up and down, and a slide that slides the load receiving platform. A drive mechanism; and an operating device that outputs a drive command for the lifting and sliding operations of the load receiving platform. In the sliding motion of the cargo cradle from the retracted position to a predetermined position toward the rear of the vehicle, the lifting drive mechanism and the slide drive mechanism are driven, and the predetermined position of the cargo cradle from the start of output by the operating device in the sliding motion The slide time until is set so as to substantially match the drive command time of the slide drive mechanism by the output of the operation device.

  In the slide operation from the storage position of the load receiving platform to the predetermined position, it is preferable that the drive command time of the slide drive mechanism is set longer than the drive command time of the elevating drive mechanism.

  In the sliding operation from the storage position of the load receiving table to the predetermined position, it is also desirable that the operating device is instructed to drive the elevation drive mechanism and the slide drive mechanism substantially simultaneously.

  In particular, in the load receiving table lifting apparatus, the lifting drive mechanism moves the load receiving table up and down by supplying hydraulic oil from the hydraulic pump, an oil tank, and hydraulic oil from the hydraulic pump or discharging hydraulic oil to the oil tank. A lift cylinder, and a communication means for communicating the oil tank and the lift cylinder. When the load receiving table is slid from the storage position to the predetermined position, the communication means is communicated by the operating device. It is desirable that a drive command for the slide drive mechanism is output substantially simultaneously.

  As in the present invention, by driving both the slide drive mechanism and the lift drive mechanism when starting the pull-out operation of the load receiving table, no noise is generated when pulling out, and the load receiving table in the retracted state is swung up and down. It is possible to prevent damage to the restricting member that regulates the load and the cargo cradle. Furthermore, even if both drive mechanisms are driven, the time required for the slide and the command output time for the slide operation are set to substantially coincide with each other. Can be used easily and with peace of mind.

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 operating device and control apparatus 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 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. It is a principal part perspective view which shows the fall prevention member of the load receiving stand 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.

  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 lifting 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 link member 5 that is supported so that one end of the slide member 4 can turn up and down, A cradle 6 is supported by the other end of the link member 5 and can be folded.

  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. The slide member 4 is driven by the expansion and contraction of a slide cylinder (not shown). The slide cylinder is a set of two, and the respective expansion and contraction rods are configured in opposite directions. These slide members 4 and slide cylinders constitute a slide drive mechanism.

  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 elevating drive mechanism.

  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 the present embodiment, the storage state is stored below the loading platform 1 as shown in FIG. 1B, and is further slid to the forefront of the slide rail 3 in terms of setting, and the vehicle can run. Refers to the state of being.

Next, the hydraulic drive device that contributes to the drive of the slide operation or the lifting operation of the load receiving platform 6 will be described. In this embodiment, the hydraulic drive device 10 shown in 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 on the downstream side of the lowering control valve SOL2 and a main relief valve R1 that defines the maximum value of the discharge pressure of the hydraulic pump P are provided. In the present embodiment, the lift operation control valve SOL1 and the lift 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.

In the present embodiment, the pressure oil return path branches from the discharge path 11 to a position downstream of the main relief valve R1 and upstream of the drawing operation control valve SOL3 or the drawing operation control valve SOL4. A bypass path 17 connected to 16 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 device 10 having such a configuration is controlled using the operation device 20 shown in FIG. 3 and a control device 30 provided in the vehicle.

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

  The operating device 20 includes buttons 21a to 21c and a transmission unit 22 that creates serial data in the ON or OFF state 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 load receiving platform. Although the operation device 20 of the present embodiment is a wireless operation device, it may be a wired operation device connected to the vehicle side (or power unit).

  The control device 30 includes an input unit 32 that inputs detection signals from the sensors 31a to 31d that detect the operation of the cargo receiver 6 and the slide member 4, a reception unit 33 that receives an output signal from the operation device 20, and a control unit. A storage unit 34 that stores a program, a control threshold value, and the like, and a calculation unit that executes arithmetic processing based on the 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 35, and an output unit 36 that outputs a command signal from the calculation unit 35 to the control valves SOL1 to SOL5, the conductor relay C, and the like.

  Each of the sensors 31a to 31d is provided on 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. A hinge that connects the base 61 and the intermediate portion 62 of the load receiving base 6 is provided with a folding sensor 31d. For example, proximity sensors and limit buttons can be used for the 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 according to the present embodiment is a position where the slide member 4 is the rearmost end in the slidable range. The rear end sensor 31a is always in a detection state (ON state) when the slide member 4 is located at a predetermined position detected along the vehicle front-rear direction.

  The intermediate sensor 31b is a detection unit that detects that the slide member 4 that slides forward of the vehicle has reached an intermediate position. The intermediate position is a position where the slide member 4 is located closer to the front of the vehicle but does not reach the foremost end of the slidable range. The intermediate sensor 31b of the present embodiment is in a non-detection state (OFF state) until reaching the midway position from the rear side of the vehicle, and is always detected when it is located forward along the vehicle longitudinal direction from the midway position. It is set to be in a state (ON state).

  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. In this embodiment, the 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 device 10 rises, so 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. Determined to have touched.

  The folding sensor 31d is a detecting means for detecting how much the intermediate portion of the load receiving tray 6 is folded with respect to the base portion. 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, the detection state (ON state) is set when the angle of the intermediate portion 62 with respect to the base 61 is reached, and the non-detection state (OFF state) is set when the angle is different from the angle. It is set to become.

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

  First, as shown in FIG. 4A, the first pull-out operation is to slide the stowage receiving stand 6 to the vehicle rear side indicated by the arrow A1. In this operation, after the main switch of the control device 3 is turned ON (time T0), the operator presses the lowering button 21b of the operation device 20 to “draw the retracted cradle toward the rear of the vehicle” (time T1). ) (See FIG. 5). That is, it is performed by the work vehicle outputting a pull-out command via the operation device 20. 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. Even in this case, by depressurizing the sealed pressure oil, the frictional force of the load receiving table 3 with respect to the slide rail 3 when performing the first pulling operation is suppressed, or damage to the load receiving table 6 is prevented. It becomes possible to do. Further, by setting the pull-in operation control valve SOL4 in a communicating state, it is possible to prevent noise from being generated 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.

  In the present embodiment, in the first pull-out operation, the pull-out operation control valve SOL3 is not simply in the communication state, but the lowering operation control valve SOL2 and the pull-in operation control valve SOL4 are also in the communication state. Further, it is characterized in that the switching control for communicating the pull-out operation control valve SOL3 and the switching control for bringing the lowering operation control valve SOL2 into communication are performed simultaneously.

  In the first pull-out operation, the lowering operation control valve SOL2 is switched to the shut-off state at time T12 (<time T2), and the pull-in operation control valve SOL4 is switched to the shut-off state at time T11 (time T2). Therefore, when the lowering button 21b of the operating device 20 is pressed, the lowering control valve SOL2 and the pulling operation control valve SOL3 respond, the slide cylinder 45 is extended while the lift cylinder 55 is depressurized, and the lift cylinder After the depressurization of 55 is completed, the cargo receiving platform 6 is pulled out by a distance required for the first pulling-out operation. As a result, based on the switching control of the pull-out operation control valve SOL3 that responds when the lowering button 21b of the operating device 20 is pressed, only the time (time T1 to time T2) required for the slide cylinder 45 to extend is the first pull-out. This is the time required for operation. That is, no additional time is added to insert the lowering control valve SOL2. Similarly, the pull-in operation control valve SOL4 is switched at the same time as the pull-out operation control valve SOL3, so that no additional time is added. Therefore, the operator who commanded the first pulling operation only needs to operate for the time that the slide cylinder 45 extends while being depressurized in response to the lowering control valve SOL2 and the pulling operation control valve SOL4, and no operation time is required. I don't feel long. In addition, when the lowering button 21b is pressed, the pull-out operation control valve SOL3 responds according to the command and the extension of the slide cylinder 45 is started, so that the operator does not feel that the performance of the pull-out operation is deteriorated. As described above, the load receiving platform lifting / lowering device 100 is slid or lifted by supplying / discharging pressure oil to / from the lift cylinder 55 and the slide cylinder 45. When the pressure oil changes with time, the operation responsiveness of the load receiving platform lifting apparatus 100 may also change. Therefore, in the first pull-out operation as in the present embodiment, the time required for the pressure release of the lift cylinder 55 (time T1 to time T12) during the time required for the extension operation of the slide cylinder 45 (time T1 to time T2) By controlling the time required for pressure release of the slide cylinder 45 (time T1 to time T11), even if the time required for pressure release varies, the time required for the extension operation of the slide cylinder 45 can be reduced. Variations can be suppressed. It is possible to suppress a change in the operation performance of the load receiving table lifting device 100.

  In particular, when the first pull-out operation is performed, it is necessary to drive the electric motor M and supply the pressure oil to the slide cylinder 45. Therefore, depending on the drive time of the electric motor M and the communication of the lowering operation control valve SOL2. There is a slight time difference from the extension start time of the slide cylinder 45. Compared with this slight time difference, the pressure oil sealed in the pressure oil supply passage 12 and the first pressure oil supply passage 14 is instantaneously released by the communication of the lowering control valve SOL2 and the pulling operation control valve SOL4. To be done. Therefore, when the slide cylinder 45 extends, the pressure relief in the pressure oil supply path 12 and the first pressure oil supply path 14 can be completed, or the slide cylinder 45 can be started to extend immediately before the completion of the pressure relief. Therefore, when the control of the present embodiment is performed, “the time of the first pulling operation for pulling the load receiving platform 6 to a predetermined position after the output to the control device 30 is started by operating the operation device 20” is “ This substantially coincides with the “drive command time for extending the slide cylinder 45 in response to the output of the operating device 20”. That is, the time required for the first pulling operation can be shortened as compared with the control in which the command is output to the pulling operation control valve SOL3 after the command is output to the descending control valve SOL2 in advance. As for the above “substantially coincidence”, there may be a case where the coincidence is not exactly due to the “slight time difference” between the driving time of the electric motor M and the extension start time of the slide cylinder 45, but the “slight time difference” that has occurred before. In practical terms, the worker feels that the operator agrees.

  The first pull-out operation is performed from time T1 to T2, and during this time, the pull-out operation control valve SOL3 is in communication. The set time for the communication state of the lowering operation control valve SOL2 is set to be shorter than the time T2 (time T1 to time T12). This set time is set only for the purpose of pressure relief of the pressure oil supply passage 12 (pressure relief of the lift cylinder 55). The set time for the communication state of the pull-in operation control valve SOL4 is also set shorter than the time T2. Similarly, it is set only for the purpose of depressurizing the first pressure oil supply passage 14. The pressure release time of the pressure oil supply path 12 and the first pressure oil supply path 14 can be changed as appropriate depending on the performance of each member constituting the slide drive mechanism.

  As described above, in the first pulling-out operation of the present embodiment, the lowering operation of the load receiving platform 6 due to the pressure release of the lift cylinder 55 is included in the operation of pulling the load receiving platform 6 to the rear side of the vehicle. Compared with the operation of pulling out to the rear side, it is a movement of a minute distance whether or not the operator can visually recognize. Therefore, in the first pull-out operation, the main pull-out operation is referred to as the vehicle rear side, and the first pull-out operation is expressed as a “slide operation” toward the vehicle rear side.

  When the first pull-out operation is completed (time T2), the intermediate sensor 31b enters a non-detection state. Switching to the non-detection state of the intermediate sensor 31b triggers the electric motor M to be in the OFF state, 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. Is done. By these controls, the first lowering operation is performed in which the lift cylinder 55 contracts and the load receiving platform 6 descends. At the time of the first lowering operation, as shown in FIG. 4B, the slide member 4 has moved about the length L1 from the foremost end position by the first pulling operation, and by the first lowering operation in the direction of the arrow A2, The intermediate portion 62 of the load receiving platform 6 is slightly inclined with respect to the base portion 61. In addition, since the load receiving platform 6 is separated from the slide rail 3 by the first lowering operation, the hydraulic pressure sensor 31c is in a non-detection state.

  When the first lowering operation is completed (time T <b> 3), the intermediate portion 62 of the load receiving platform 6 is inclined at a predetermined angle with respect to the base portion 61. When the folding sensor 31d detects that the predetermined angle has been reached, this detection is used as a trigger to switch the lowering operation control valve SOL2 to the shut-off state and the pulling operation control valve SOL3 to be switched to the communication state. The electric motor M is driven. By these controls, the slide cylinder 45 is extended again, and the second pulling-out operation in the arrow A3 direction is started as shown in FIG.

  Then, when the slide member 4 moves to the last end and the second pulling-out operation is completed (time T4), the rear end sensor 31a enters the detection state (ON state). With this 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 pulling 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 grounded 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.

  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. 6 and 7. FIG. 6 is a side view of the load receiving table lifting device 100 showing the pulling operation, and FIG. 7 is a time chart showing operation commands to the operating device 20 and the control device 30 in the pulling operation.

  In the load receiving platform lifting / lowering device 100 of the present embodiment, in the “pull-in operation” from the ground receiving state to the state where the load receiving stand 6 is folded and stored below the load receiving platform 1 (the vehicle travelable state), The drawing operation, the second raising operation, and the second drawing operation are sequentially performed.

  In the first ascending operation, when the operator presses the ascending button 21a of the operating device 20 with the main switch turned on (time T6), the load receiving platform 6 ascends in the direction of the arrow B1 shown in FIG. When the ascending button 21a is pressed, the electric motor M is driven by energizing the conductor relay C, and the ascending operation control valve SOL1 and the pulling out 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.

  The load receiving platform 6 is folded to the state shown in FIG. 6B by the first ascending operation, and the folding sensor 31d enters the detection state when the intermediate portion 62 with respect to the base 61 of the load receiving platform 6 is at a predetermined angle (time T7). After the first ascending operation is completed, the operation 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 slide member 4 is slid to the middle position of the slidable range (position separated from the foremost end of the slidable range by the length L1) by the first pull-in operation, the intermediate sensor 31b enters the detection state (time T8). After the detection by the intermediate sensor 31b, 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 SOL3 are in the same time. Is in 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. 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 lifting operation is performed from the first pulling operation. Noise can be prevented during switching.

  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 slight 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.

  When the second pull-in operation is completed and the storage state is entered, the lowering prevention member 7 shown in FIG. The descending prevention member 7 is attached to the first engagement member 71 attached to the outer side surface of the slide rail 3 and the back surface of the intermediate portion 62 of the load receiving platform 6 (the upper surface when the load receiving platform 6 is folded). And the second engaging member 72. The first engaging member 71 has a locking portion 71b that extends downward from the mounting portion 71a with the slide rail 3 and further protrudes outward at its tip. The second engagement member 72 has a substantially Z-shaped cross-sectional shape as shown in the figure, and is formed on the intermediate portion 62 of the load receiving platform 6 via the lower mounting piece 72a.

It is fixed. Further, the protruding piece 72b on the upper side of the second engagement member 72 is in a state of facing the locking portion 71b of the first engagement member 71 by the second pull-in operation (movement of the arrow B4 in the figure). . In the retracted state of the load receiving platform elevating device 100, the protruding piece 72b and the locking portion 71b are opposed to each other, so that the protruding piece can be lifted even if the load receiving stand 6 is unexpectedly lowered while the vehicle is stopped or traveling. The lowering operation of the portion 72b is locked by the locking portion 71b. That is, it is possible to prevent the cargo receiving platform 6 from being greatly lowered.

  As shown in the enlarged view of FIG. 8B, the descending prevention member 7 is provided with a gap of height H1 between the protruding piece portion 72b and the locking piece portion 711b of the locking portion 71b in the retracted state. ing. Further, a gap having a height H2 is also provided between the projecting piece portion 72b and the attachment portion 71a. Since the second pull-in operation is performed in a state where a gap is provided above and below the projecting piece portion 72b, the lowering prevention member 7 does not hinder the second pull-in operation. Furthermore, even if the load receiving table elevating device 100 is unexpectedly lowered, the descent can be stopped when it is lowered by the height H1. In the configuration of the descending prevention member 7, the upward / downward swinging and descending regulation by the descending prevention member 7 can be released by performing the pulling operation toward the rear of the vehicle.

  The descending prevention member 7 is provided so as to be interposed between the slide rail 3 and the load receiving platform 6 and is a space below the loading platform 1. In addition, from the viewpoint of preventing vertical swinging while the vehicle is running, it is desirable that the gaps (heights H1 and H2) around the locking piece 711b and the overhanging piece 72b are also small. Therefore, as in this embodiment, when the first pulling operation is performed, the lowering operation control valve SOL2 and the pulling operation control valve SOL3 are simultaneously in communication (time T1 in FIG. 5), and the lowering operation control is performed. Only the switching control to the communication state of the valve SOL2 is not preceded, and the extension of the slide cylinder 45 can be started substantially simultaneously with the pressure release of the lift cylinder 55, and between the protruding piece portion 72b and the locking piece portion 711b. Even if the gap (height H1) is small, the interference between the protruding piece 72b and the locking piece 711b can be suppressed. Therefore, a safe first pull-out operation can be performed. In particular, unlike the present embodiment, in the case of control to switch from the ascending operation to the pull-in operation only by sensor detection, the response accuracy of the operation switching may differ depending on the change in temperature or the secular change of pressure oil. If the response accuracy is different, the size of the gap between the projecting piece 72b and the locking piece 711b in the retracted state is not stable. In such a configuration, the effect of avoiding interference by controlling the first pulling-out operation described above becomes significant. Further, even when the load receiving platform 6 is stored in a desired state, it is simultaneously controlled so that not only the lift cylinder 55 is depressurized but also the slide cylinder 45 is extended. Occurrence of the pulling-out operation in a state where the one part 711b interferes can be avoided.

  In addition, when a lowering prevention member different from that shown in FIG. 8 is applied to the load receiving platform elevating device 100, for example, in a configuration in which the lowering prevention functions by engaging the engaging member and the engaged member in the retracted state. A great effect can be obtained by simultaneously bringing the lowering operation control valve SOL2 and the drawing operation control valve SOL3 into communication. That is, since the slide start of the load receiving platform 6 is not delayed after the operation device 20 outputs the extraction command, the first extraction operation is started before the lowering prevention device functions firmly, so that the extraction operation is hindered. Never happen.

  As described above, in the first pulling operation, at least the lowering control valve SOL2 and the pulling operation control valve SOL3 are controlled to be switched at the same time. However, the pulling operation and the pulling in of the load receiving platform 6 are not necessarily performed as in the present embodiment. Any of the operations may not be configured or controlled by four operations (substeps). For example, the pulling-out operation may be composed of two sub-steps of a sliding operation toward the rear of the vehicle and a lowering operation. A configuration in which the number of substeps is different between the drawing operation and the drawing operation may be employed.

  With regard to the pulling-out operation for pulling out the cargo receiving platform 6 in the storage state, when the purpose is to move the length L1 in the first pulling-out operation as in the present embodiment, the length of L1 is the extension of the lowering prevention device 7. If the size of the piece 72b is set so as not to face the locking piece 711b, at least the first lowering operation can be performed, but the length may be set longer than that. At this time, the time required for the first pull-out operation (time T1 to T2) can also be set to a predetermined time that can be set as appropriate. In addition, regarding the “predetermined time”, the pulling operation of the operating device is output from the loading platform in the retracted state in the loading platform lifting apparatus of the other embodiment in which the pulling operation is completed by one pulling operation and one descending operation. The time required to reach the position (the end position) at which one pull-out operation is completed from time can also be used. Of course, in this “single pull-out operation”, the same effects as those in the first pull-out operation of the present embodiment can be obtained as long as the control and configuration are such that pressure release by the lift cylinder is also performed.

  In addition, the lowering control valve SOL2 and the pulling operation control valve SOL3 may have the same or different performance regarding the response of switching between communication or cutoff. For example, if a response of switching control of the pull-out operation control valve SOL3 is superior to that of the lowering operation control valve SOL2, the driving time of the electric motor M and the slide cylinder 45 due to the communication of the lowering operation control valve SOL2 The “slight time difference” that can occur between the extension start times can be further reduced. Therefore, “the time of the first pulling operation for pulling the load receiving platform 6 to a predetermined position after the operation device 20 is operated and the output to the control device 30 is started” is “the slide cylinder receiving the output of the operation device 20. This is preferable because it coincides with the “drive command time for extending 45”.

  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 Operating device 30 Control device 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 (4)

A cradle that can move up and down relative to the vehicle and is slidable underneath the pallet
An elevating drive mechanism for elevating and lowering the load receiving table;
A slide drive mechanism for sliding the load receiving table;
An operating device for outputting drive commands for the lifting operation and the sliding operation of the load receiving table;
With
In the sliding operation from the retracted position to the predetermined position toward the rear of the vehicle, the lift drive mechanism and the slide drive mechanism are driven,
The slide time from the start of output by the operating device in the sliding operation to the predetermined position of the load receiving platform is set to substantially match the drive command time of the slide drive mechanism by the output of the operating device. Cargo stand lifting device. The slide command mechanism drive command time is set to be longer than the drive command time of the lift drive mechanism in the sliding operation from the storage position of the load receiving platform to the predetermined position. Loading platform lifting device. 2. The sliding operation from the storage position of the load receiving platform to the predetermined position is performed by the operation device so that the elevation drive mechanism and the slide drive mechanism are commanded substantially simultaneously. Loading platform lifting device. The lifting drive mechanism includes a hydraulic pump, an oil tank, a lift cylinder that moves the load receiving table up and down by supplying hydraulic oil from the hydraulic pump or discharging hydraulic oil to the oil tank, the oil tank, Communication means for communicating the lift cylinder;
The sliding command from the storage position to the predetermined position in the sliding movement of the load receiving platform is such that the drive command for the slide drive mechanism is output substantially simultaneously with the communication means being communicated by the operating device. The load receiving table lifting device described in 1.

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