JP2009202667A - Storage type cargo receiving platform elevating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a storage type cargo receiving platform elevating device capable of drawing a cargo receiving platform in a lower part space of a vehicle in proper timing in storing motion. <P>SOLUTION: The storage type cargo receiving platform elevating device stores the cargo receiving platform 5 in the space on the lower part side of the vehicle. The device has an arm sensor 28 to detect an angle of a lift arm 30, and a gate sensor 18 to detect a folding state of the cargo receiving platform 5. The device detects that it is in the storing motion of the cargo receiving platform 5 and that the cargo receiving platform 5 arrives at a setting angle β before it arrives at storing height, based on signals from the arm sensor 28 and the gate sensor 18. Then, the device decelerates speed arriving at the storing height after it arrives at the setting angle β with respect to driving speed of a lift cylinder 22 before it arrives at the setting angle β. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a retractable cradle lifting device that can be stored in a lower space of a vehicle.

  The load receiving platform lifting device lifts and lowers the load receiving platform between the height of the loading platform floor of the vehicle and the height of the ground, and supports the loading and unloading work of the operator on the loading platform of the vehicle. Among these, the one that is configured to be able to be stored in the space on the lower side of the vehicle by sliding the folded cradle forward from the working position is called a retractable cradle lifting device (patent) Reference 1 etc.).

JP 2006-88946 A

  In the retractable load receiving device lifting device, when the load receiving stand is stored in the lower part of the vehicle, the folded load receiving stand is lifted and moved forward when it reaches the storage height set near the horizontal position to move to the lower space of the vehicle. Pull in. In general, in many cases, a circuit is assembled so that such a series of operations for storing the cradle is continuously executed by one operation. In other words, even if there is no command to raise or lower the cargo cradle, it detects the folded state and height position of the cargo cradle during the storage operation and automatically moves forward from the lift based on these detection signals. The operation of the cradle is shifted to the above.

  However, hydraulic cylinders are generally used for lift cylinders that raise and lower the load receiving table and slide cylinders that slide back and forth, so during the storage operation, the sensor detects that the load receiving table has reached the storage height. The timing of shifting from the forward movement to the forward movement may vary depending on the viscosity of the hydraulic oil. Since the viscosity of the hydraulic oil varies depending on the outside air temperature, for example, in the winter when the viscosity of the hydraulic oil is likely to increase, the response of the operation generally tends to decrease.

  If such an operation delay becomes large, during the storage operation, the load receiving platform will move forward after passing through the set allowable range with a slight margin above and below the storage height, and before and after the load receiving table. Interference may occur between the rails that guide the movement and the components of the cradle, such as the rail guides that engage the rails. If interference occurs between the parts, there is a concern about problems such as damage to component parts and generation of abnormal noise.

  The present invention has been made in view of the above points, and an object of the present invention is to apply a retractable load receiving device lifting / lowering device capable of pulling a load receiving table into a lower space of a vehicle at an appropriate timing during a storing operation.

  In order to achieve the above object, the first invention provides a load receiving base having a load receiving base base end and a load receiving base main body folded on the load receiving base, a guide rail provided at a lower portion of the vehicle, and the guide rail. And a slide cylinder that slides the slide unit back and forth, a lift arm that connects the load receiving table to the slide unit so as to be able to move up and down, and a lift cylinder that moves the load receiving table up and down. In the retractable load receiving device elevating device for storing the load receiving table in the space on the lower side of the vehicle by sliding the load receiving table forward when the load receiving table is folded when it is raised to the storage height. Arm angle detecting means for detecting the angle of the lift arm, folding detection means for detecting the folded state of the load receiving table, and the arm angle detecting means. Based on the signals from the means and the fold detection means, the load receiving platform has reached a predetermined set angle set within an angle range until the load receiving table is being stored and reaching the stored height. And a control means for reducing the speed from reaching the set angle to reaching the storage height with respect to the drive speed of the lift cylinder before reaching the set angle. It is characterized by.

  According to a second invention, in the first invention, a hydraulic pump that discharges pressure oil to be supplied to the slide cylinder and the lift cylinder, a pressure oil supply line that connects the lift cylinder and the hydraulic pump, A control valve for raising operation for communicating or blocking the pressure oil supply line, a pressure oil discharge line branched from the pressure oil supply line and connected to the hydraulic oil tank, and a connection or blocking for the pressure oil discharge line The lowering operation control valve, and the control means opens the raising operation control valve to start the storing operation of the load receiving table, and the storing height is reached after the load receiving table reaches the set angle. Until reaching the control valve, in addition to the raising operation control valve, the lowering operation control valve is opened to return a part of the pressure oil supplied to the lift cylinder to the hydraulic oil tank.

  According to a third invention, in the second invention, a throttle valve that is provided in the pressure oil discharge pipe and restricts a maximum flow rate of the pressure oil returned to the hydraulic oil tank among the pressure oil supplied to the lift cylinder. It is characterized by having.

  According to a fourth invention, in the first invention, a hydraulic pump that discharges pressure oil to be supplied to the slide cylinder and the lift cylinder, a pressure oil supply line that connects the lift cylinder and the hydraulic pump, A control valve for raising operation for communicating or blocking the pressure oil supply pipe and a flow rate control valve for controlling a flow rate of pressure oil flowing through the pressure oil supply pipe, and the control means includes the control valve for raising action Is opened to start storing operation of the load receiving platform, and the flow rate control valve reduces the supply flow rate to the lift cylinder from when the receiving table reaches the set angle until reaching the storing height. It is characterized by that.

  According to a fifth invention, in the first invention, a hydraulic pump that discharges the pressure oil supplied to the slide cylinder and the lift cylinder, a pressure oil supply pipe that connects the lift cylinder and the hydraulic pump, A control valve for raising operation for communicating or blocking the pressure oil supply line; and an electric motor for driving the hydraulic pump; and the control means opens the control valve for raising operation to perform the storing operation of the load receiving platform. The driving speed of the electric motor is reduced between the time when the load receiving platform reaches the set angle until the stowage height is reached.

  According to a sixth invention, in any one of the first to fifth inventions, a support arm projecting rearward of the slide unit, and a rear end portion of the support arm are rotatably provided. A support roller on which a load receiving base body folded against an end rolls, and the arm angle detection means is a proximity switch provided on the support arm so as to face the lift arm having the storage height. The folding detection means is an angle sensor provided on a hinge connecting the base end portion of the load receiving base and the main body portion, and detecting an angle of the load receiving base main body portion with respect to the load receiving base base end portion; The means detects that the load receiving table has reached a set angle based on the angle of the load receiving body main body portion that rolls in contact with the support roller and sleeps horizontally as the lift arm rises during the storage operation, , Receiving platform by the detection signal of the serial arm angle detecting means and detecting the arrival in the storage height.

  According to the present invention, the receiving platform can be pulled into the lower space of the vehicle at an appropriate timing during the storing operation.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a side view showing the overall structure of a vehicle equipped with a retractable load receiving device lifting apparatus according to a first embodiment of the present invention. Hereinafter, the left side in FIG. 1 is the front side of the vehicle, the right side is the rear side, the front side in the direction orthogonal to the plane of the paper is the left side, and the back side in the direction orthogonal to the plane of the paper is the right side.
The vehicle shown in FIG. 1 includes a driver's cab 2 provided in front of a vehicle body (vehicle frame) 1, a loading platform 3 provided on the vehicle body 1, and a retractable loading platform lifting device 4 provided at the rear of the vehicle body 1. I have. The retractable load receiving platform lifting / lowering device 4 can fold the load receiving stand 5 to store the load receiving stand in the space on the lower side of the vehicle body 1 at the time of traveling operation, etc. Therefore, the load receiving platform 5 is slid rearward and deployed, and can be raised and lowered between the floor height of the loading platform 3 and the ground height.

  FIG. 2 is a perspective view showing the detailed structure of the retractable load receiving device elevating device 4 during storage, and FIG. 3 is a perspective view showing the detailed structure of the retractable load receiving device lifting device 4 during deployment.

  2 and 3, the retractable load receiving table elevating device 4 elevates and lowers the load receiving platform (platform) 5, a slide drive unit 6 that slides a unit including the load receiving table 5 and the like in the front-rear direction, and the load receiving table 5. An elevating drive unit 7 is provided.

  The slide drive unit 6 includes a pair of left and right guide rails 8 extending in the front-rear direction provided at the lower portion of the vehicle body 1, a slide unit 29 that can move back and forth along the guide rails 8, and a support roller that protrudes behind the slide unit 29. 12 is provided. The slide unit 29 includes left and right sliders 9 that can run along the left and right guide rails 8, a connecting member 10 that connects these sliders 9, left and right brackets 11 provided on the left and right outer sides of the slider 9 in the connecting member 10, and A pair of left and right double-acting slide cylinders 14 for sliding the left and right sliders 9 back and forth are provided.

  The guide rail 8 is provided with stoppers 15 and 16 (see FIGS. 8 to 14 later) for limiting the range of movement of the slider 9 in the front-rear direction. The rear end side stopper 16 is provided with a rear end sensor 17 (see FIG. 5 below) for detecting whether or not the slider 9 is in contact with the stopper 16 (referred to as a rear end position). The support rollers 12 are rotatably provided at the rear ends of the left and right support frames 13 provided so as to protrude rearward from the left and right sliders 9, respectively. Further, the support frame 13 is provided with an arm sensor 28 so as to face a target (not shown) provided on the lift arm 30 when the lift arm 30 is at the retracted height set near the horizontal position. For example, a proximity switch is used as the arm sensor 28 and outputs a detection signal when the lift arm 30 is at the retracted height.

  The slide cylinder 14 is a double-acting hydraulic cylinder, the bottom (not shown) side is housed and fixed in the support arm 13 of the support roller 12, and the tip of the rod is below the guide rail 8. It is connected to a fixed support member 31. As the slide cylinder 14 extends, the slide unit 29 slides rearward along the guide rail 8, and the stowage receiving stand 5 protrudes rearward of the vehicle body 1 (the state shown in FIG. 9). On the contrary, the slide unit 29 slides forward in accordance with the retracting operation of the slide cylinder 14, and the load receiving platform 5 folded in the storage height slides forward and is stored in the lower space of the vehicle (FIG. 8). Status).

  The elevating drive unit 7 includes a lift arm 30 that connects the load receiving table 5 to the slide unit 29 so as to be movable up and down, and a lift cylinder 22 that moves the load receiving table 5 up and down. The lift arm 30 is connected to a first arm (tilt arm) 19 whose upper end is rotatably supported by the bracket 11, a front end is connected to the first arm 19, and a rear end is rotatably connected to the load receiving platform 5. The second arm 20 includes a third arm (compression arm) 21 having a front end portion rotatably connected to the bracket 11 and a rear end portion rotatably connected to the load receiving platform 5. On the other hand, the lift cylinder 22 is a single-acting hydraulic cylinder whose front end is rotatably connected to the lower end of the first arm 19 and whose rear end is rotatably connected to the second arm 20. The second and third arms 20 and 21 form a parallel link, and the substantially horizontal posture of the load receiving platform 5 that moves up and down as the lift cylinder 22 expands and contracts is always maintained except during tilting (described later). ing. The first arm 19, the second arm 20, the third arm 21, and the lift cylinder 22 are provided in pairs on the left and right.

  The load receiving platform 5 includes a load receiving platform base end portion 23 supported by the elevating drive unit 7, a load receiving platform main body portion 25 connected to the load receiving platform base end portion 23 via a hinge 24, and a hinge 26 to the load receiving platform main body portion 25. It is comprised by the load receiving stand front-end | tip part 27 connected via. Both ends of the hinge 24 are rotatably connected to the load receiving base end portion 23 and the load receiving base body portion 25 through different pins (not shown), respectively. Twenty-five rotation mechanisms have a double joint structure via the hinge 24. Similarly to this, the rotation mechanism of the load receiving table front end portion 27 with respect to the load receiving table main body portion 25 has a double joint structure through the hinge 26. As a result, the cargo cradle body 25 and the cargo cradle tip 27 pivot upward from the unfolded state (FIG. 3) and fold over the cargo cradle base end 23 and the cargo cradle body 25 as shown in FIG. This is a possible configuration.

  At this time, although not shown in FIGS. 2 and 3, the hinge 24 that connects the load receiving base end portion 23 and the load receiving base main body 25 has a gate as a folding detection means for detecting that it is in the storing operation. A sensor 18 (see FIG. 5) is provided. The gate sensor 18 can be an angle sensor that detects an angle of the hinge 24 with respect to the load receiving base end portion 23. As described above, since the hinge 24 has a double joint structure, when the load receiving base body 25 is folded on the load receiving base base 23, the load receiving base main body 25 is rotated 90 degrees with respect to the hinge 24. The hinge 24 is constrained by the load receiving base body 25 and starts to rotate with respect to the load receiving base 23, and finally the load receiving surfaces of the load receiving base 25 and the load receiving base 23 face each other. Therefore, when actually storing the load receiving platform 5 after work, as described later, the load receiving platform tip 27 and the load receiving platform main body 25 are folded and leaned on the support roller 13 (the state shown in FIG. 10 later). The lift arm 30 is raised, but at this time, the angle of the hinge 24 with respect to the load receiving base end portion 23 has not reached 90 degrees. The angle of the hinge 24 relative to the load receiving base end 23 when the load receiving base 5 is deployed is 0 (zero), and the load receiving base base 23 when the load receiving main body 25 is leaned against the support roller 13 at the ground contact position. When the angle of the hinge 24 with respect to the angle α is 0 (0 <α <90 °), the gate sensor 18 determines that the angle of the hinge 24 with respect to the load receiving base end 23 is equal to or larger than the set angle β (α <β <90 °). It is set to output a detection signal.

  At the left and right ends of the connecting member 10 of the slide drive unit 6 described above, an operation unit 34 for operating the load receiving platform lifting device 4 and a hydraulic drive device (shown in FIG. 4) for driving the cylinders 14 and 22 ( Power unit) 33 is provided.

  FIG. 4 is a hydraulic circuit diagram illustrating a configuration example of the hydraulic drive device 33.

  The hydraulic drive device 33 shown in FIG. 4 includes an electric motor (prime mover) 36, a hydraulic pump 37 that is driven by the electric motor 36 and discharges pressure oil, and suction of the hydraulic pump 37 as elements of the hydraulic circuit related to the lifting operation of the load receiving platform 5. A hydraulic oil tank 38 provided on the side, a pressure oil supply line 39 for supplying pressure oil discharged from the hydraulic pump 37 to the bottom side of the lift cylinder 22, and communication of the flow of pressure oil in the pressure oil supply line 39. A control valve 40 for raising operation (lift cylinder extending operation) for switching the shut-off state and a downstream of the control valve 40 for raising operation in the pressure oil supply line 39 are branched to the hydraulic oil tank 38 and communicated with the bottom of the lift cylinder 22. The pressure oil discharge pipe 41 for returning the return oil from the side to the hydraulic oil tank 38, and switching the communication / cut-off state of the pressure oil flow in the pressure oil discharge pipe 41 The control valve 42 for the lowering operation (degeneration operation) of the foot cylinder 22 and the maximum flow rate of the pressure oil that flows through the pressure oil discharge pipe 41 provided downstream of the control valve 42 for the lowering operation in the pressure oil discharge pipe 41 are limited. And a relief valve 44 for defining the maximum value of the discharge pressure of the hydraulic pump 37.

  When the electric motor 36 is driven (when the hydraulic pump 37 is driven), when a drive command signal is input to the solenoid drive unit 40a of the raising operation control valve 40, the raising operation control valve 40 is connected to the left communication position in FIG. And the bottom side of the lift cylinder 22 and the hydraulic pump 37 are connected via a pressure oil supply line 39. At this time, when the lowering control valve 42 is at the lower cutoff position in FIG. 4, the pressure oil discharged from the hydraulic pump 37 is supplied to the bottom side of the lift cylinder 22 via the pressure oil supply line 39. The lift cylinder 22 is driven in the extending direction, and as a result, the load receiving platform 5 is raised.

  On the other hand, when a drive command signal is input to the solenoid drive unit 42a of the lowering control valve 42, the lowering control valve 42 is switched to the upper communication position in FIG. A tank 38 is connected via a pressure oil discharge pipe 41. At this time, if the electric motor 36 is stopped (or if the raising operation control valve 40 is in the cut-off position on the right side in FIG. 4), no hydraulic oil is supplied from the hydraulic pump 36 to the lift cylinder 22. Due to the weight of 5 or the like, a force is applied to the rod of the lift cylinder 22 toward the retracting operation side, and the pressure oil is pushed away from the bottom side of the lift cylinder 22. As a result, the return oil from the lift cylinder 22 is returned to the hydraulic oil tank 38 via the pressure oil discharge pipe 41, the lift cylinder 22 operates in the retracting direction, and the load receiving platform 5 is lowered.

  The hydraulic drive device 33 is branched from the upstream side of the control valve 40 for raising the lift cylinder 22 in the pressure oil supply line 39 as an element of the hydraulic circuit relating to the back and forth movement of the load receiving platform 5, and the rod of the slide cylinder 14. Pressure oil supply line 46 for supplying pressure oil to the side, and pressure for supplying pressure oil to the bottom side of the slide cylinder 14 by branching from the downstream side of the throttle valve 47 and the check valve 48 in the pressure oil supply line 46 An oil supply line 49, a control valve 50 for rearward movement (for extension operation) that switches communication / blocking state between the hydraulic pump 37 and the bottom side of the slide cylinder 14 provided in the pressure oil supply line 49, for rearward movement A pressure oil discharge pipe 51 branched from the pressure oil supply pipe 49 at a position downstream of the control valve 50 and connected to the hydraulic oil tank 38, and the pressure oil discharge pipe And a control valve 52 of the 51 forward movement for switching communication and cut-off state of the bottom side of the slide cylinder 14 and the hydraulic tank 38 is provided on (for restricted operation).

  When the slide cylinder 14 is extended, when the electric motor 36 and the hydraulic pump 37 are driven, a drive command signal is output to the solenoid drive unit 50a of the backward movement control valve 50, and the backward movement control valve 50 is moved to the upper side in FIG. To the communication position, the bottom side of the slide cylinder 14 and the hydraulic pump 38 are communicated. At that time, if the forward movement control valve 52 is in the lower cutoff position in FIG. 4, the pressure oil is supplied to both the rod side and the bottom side of the slide cylinder 14 via the pressure oil supply lines 46 and 49. However, the force to push the rod from the bottom side is superior due to the pressure receiving area difference, and the pressure oil discharged from the hydraulic pump 37 is returned to the bottom side via the pressure oil supply line 49 together with the return oil from the rod side of the slide cylinder 14. To be supplied. As a result, the slide cylinder 14 is driven in the extending direction, and the load receiving platform 5 and the like slide backward.

  On the other hand, when the slide cylinder 14 is retracted, when the electric motor 36 and the hydraulic pump 37 are driven, a drive command signal is output to the solenoid drive unit 52a of the forward movement control valve 52, and the forward movement control valve 52 is shown in FIG. To the upper communication position, the bottom side of the slide cylinder 14 and the hydraulic oil tank 38 are communicated. At this time, if the control valve 50 for rearward movement is in the lower cutoff position in FIG. 4, the pressure oil supply pipe 49 for supplying the pressure oil to the bottom side of the slide cylinder 14 is shut off, and the pressure oil supply pipe The passage 49 communicates with the hydraulic oil tank 38 via the pressure oil discharge pipe 51. Accordingly, the pressure oil discharged from the hydraulic pump 37 is supplied to the rod side of the slide cylinder 14 via the pressure oil supply line 46, and the return oil from the bottom side returns to the hydraulic oil tank 38 via the pressure oil discharge line 51. . As a result, the slide cylinder 14 is driven in the retracting direction, and the load receiving platform 5 and the like slide forward.

  The slide cylinder 14 may be held in a closed circuit state when the load receiving platform 5 is raised or lowered. However, in order to firmly fix the position of the slider 9 which is the base of the raising and lowering operation, the backward movement control is performed. The slider 50 may be pressed against the rear end side stopper 16 by urging the rod of the slide cylinder 14 in the extending direction while keeping the valve 50 in the communicating position.

  FIGS. 5 and 6 are electric circuit diagrams showing the configuration of the main part relating to the drive control of the retractable load receiving table elevating device 4.

  The electric circuit shown in FIGS. 5 and 6 includes the electric motor 36, the sensors 17, 18, and 28, the solenoid driving portions 40a, 42a, 50a, and 52a of the control valves 40, 42, 50, and 52, as well as a retractable load receiver. Main power switch 60 of the platform lifting device 4, a power lamp 61 for displaying ON / OFF of the main power, and an operation switch for operating ON / OFF of a drive command signal (energization) to the solenoid drive units 40a, 42a, 50a, 52a 62, 63, relay coils R1, R2, R3, R4, R5, RA, T1, CT, and relays that operate when these relay coils R1, R2, R3, R4, R5, RA, T1, CT are excited, respectively. Contacts R1 ′, R2 ′ and R2 ″, R3 ′, R4 ′, R5 ′, RA ′, T1 ′ and CT ′ are provided.

  The relay contacts R1 ′ and R2 ′ are normally open contacts that are turned on when the relay coils R1 and R2 are excited, and the relay contacts R2 ″ and R5 ′ are turned off when the relay coils R2 and R5 are excited. The relay contacts R3 ′ and R4 ′ are overlapping contacts, and one of the two contacts is ON and the other is OFF, and the relay coils R3 and R4 are respectively contacted. The relay coil T1 is an on-delay timer coil, and when the excitation state continues for a set time, the corresponding on-delay timer contact T1 ' The main power switch 60, the power lamp 61, and the operation switches 62 and 63 are, for example, the operation unit 34 (see FIG. 2 or FIG. 3). It is disposed to the remote control or the like and the loading platform 3.

  Although the operation of the circuit will be described later, the electric circuit shown in FIG. 5 sends drive command signals to the solenoid drive units 40a, 42a, 50a, 52a of the control valves 40, 42, 50, 52, the electric motor 36, and the like. It plays the role of a control means that outputs and controls the retractable load receiving table elevating device 4. As shown in FIG. 7, this electric circuit has a function of reducing the ascending speed immediately before switching from the raising operation of the load receiving platform 5 to the forward movement during the storage operation of the load receiving platform 5. That is, during the storage operation of the load receiving platform 5, the lifting operation control valve 40 is switched to the communication position at the rising operation start time t <b> 1 of the load receiving platform 5 (angle = 0 with respect to the load receiving platform base end 23 of the hinge 24). 5 is raised, at time t2 (reaching the set angle β), the lowering control valve 42 is opened, and then until time t3 when the load receiving platform 5 reaches a substantially horizontal storage height (set angles β to 90). In the meantime), the lowering control valve 42 is opened in addition to the raising control valve 50. As a result, at time t2 to t3, the flow rate limited by the throttle 43 in the pressure oil flowing through the pressure oil supply line 39 is returned to the hydraulic oil tank 38, so that the flow to the lift cylinder 22 compared to time t1 to t2. The supply flow is reduced. As a result, during the storage operation, the ascending speed of the load receiving platform 5 changes before and after reaching the set angle β, and is between 90 ° from the set angle β (that is, a predetermined time immediately before the load receiving table 5 reaches the stored height). The ascending speed is decelerated compared to when the storing operation is started. The speed change rate can be adjusted by setting the diaphragm 43. For example, after reaching the set angle β, the rising speed can be reduced to about 25 to 30%.

  Next, operations and effects of the retractable load receiving table lifting / lowering device 4 of the present embodiment will be described with reference to FIGS. 8 to 14 in addition to FIGS. 4 to 6. 8 to 14, the operation unit 34 is not shown.

(1) Unloading operation of the load receiving table First, the unloading table unfolding operation for shifting the receiving table 5 from the stored state shown in FIG. 8 to the working state shown in FIG. First, the main power switch 60 is turned on when using the load receiving table lifting device. When the main power switch 60 is turned on, the power lamp 61 is lit. When the operation switch 63 is turned on when the load receiving platform 5 is in the retracted position as shown in FIG. 8, the solenoid drive unit 50a is excited through the NC (normally closed) side contact of the overlapping relay contact R3 ′ for backward movement. The control valve 50 is switched to the communication position. At the same time, the circuit indicated by the arrow A3 is energized, and the relay coils CT and T1 (see FIG. 6) are excited. As a result, the relay contact CT ′ is closed and the electric motor 36 is driven. As a result, the pressure oil from the hydraulic pump 37 is supplied to the bottom side of the slide cylinder 14, the slide cylinder 14 extends, and the load receiving platform 5 moves rearward.

  Thereafter, as shown in FIG. 9, when the slider 9 comes into contact with the rear end side stopper 16, the rear end sensor 17 is turned on, and in FIG. 5, a circuit for energizing the relay coil R3 is opened to excite the relay coil R3. The relay contact R3 ′ is switched to the NO (normally open) side contact. When the relay contact R3 'is switched, the solenoid drive unit 42a is energized and the lowering control valve 42 is switched to the communication position. At the same time, the energization of the circuit shown in FIG. The relay contact CT ′ is opened and the electric motor 36 is stopped. As a result, the hydraulic pump 37 is stopped and the holding pressure on the bottom side of the lift cylinder 22 is released, the lift cylinder 22 is retracted by the weight of the load receiving platform 5 and the arms 19 to 21 and the lift arm 30 is rotated downward. . During this time, as the cradle base end portion 23 descends, the cradle body portion 25 and the cradle tip end portion 27 gradually rise while rolling on the support roller 12, and finally the load cradle as shown in FIG. The base end portion 23 is grounded, and the load receiving body main body portion 25 and the load receiving stand distal end portion 27 are leaned against the support roller 12.

  When the load receiving stand 5 is in the posture as shown in FIG. 10, the operator unfolds the load receiving stand 5 in a folded state. In this case, first, a grip (not shown) provided on the cargo cradle body 25 is pulled to expand the cargo cradle body 25 in a substantially horizontal state (see FIG. 11). Subsequently, a grip (not shown) provided at the tip of the cargo cradle 27 is pulled to expand the tip of the cargo cradle 27 in a substantially horizontal state (see FIG. 12).

(2) Elevating / lowering operation (work support) operation Next, an elevating operation during the operation of the load receiving platform 5 in the retractable load receiving device elevating device 4 will be described with reference to FIGS. When the operation switch 62 is pressed after the load receiving platform 5 is deployed, the solenoid drive unit 40a is energized through the NC contact of the overlapping relay contact R4 ′, and the raising operation control valve 40 is switched to the communication position. At the same time, the circuit indicated by the arrow A1 is energized, the relay coils CT and T1 (see FIG. 6) are excited, the relay contact CT ′ is closed, and the electric motor 36 is driven. As a result, the pressure oil from the hydraulic pump 37 is supplied to the bottom side of the lift cylinder 22 and the lift cylinder 22 is driven in the extending direction, and the load receiving platform 5 is brought to the floor surface height of the vehicle loading platform 3 as shown in FIG. Can be raised.

  At this time, since the solenoid drive unit 40a on the lifting movement side of the lift cylinder 22 and the solenoid drive unit 50a on the rearward movement side of the slide cylinder 14 are energized, the control valve 50 for rearward movement becomes the communication position, When it is raised, the slider 9 is always pressed against the rear end side stopper 16.

  On the other hand, when the cargo receiving platform 5 is lowered, the operation switch 63 is operated. Since the relay contact R3 'is switched to the NO side contact after the load receiving platform 5 is deployed, when the operation switch 63 is pressed, the solenoid drive unit 42a is energized and the lowering operation control valve 42 is switched to the communication position. During this time, since the electric motor 36 is in a stopped state, the pressure oil on the bottom side of the lift cylinder 22 is released and the load receiving platform 5 is lowered.

  As shown in FIG. 12, when the operation switch 63 is further pressed in a state where the load receiving base end portion 23 is grounded, the lift cylinder 22 is further retracted, and the first arm (tilt arm) 19 is rotated to rotate the parallel link. The parallelogram's vertex position collapses. Then, since the load receiving platform 5 that has maintained a substantially horizontal posture shifts downward (tilt) toward the rear, the front end side of the load receiving table distal end portion 27 is close to the ground as shown in FIG. Can be easily loaded on the receiving tray 5.

  Further, when the load receiving platform 5 is lowered, the electric motor 36 is stopped. However, since the control valves 50 and 52 for the front and rear operation are both in the cutoff position, the pressure on the bottom side and the rod side of the slide cylinder 14 is maintained. The state where the slider 9 is in contact with the rear end side stopper 16 is maintained.

  In the circuits shown in FIGS. 5 and 6, the electric motor 36 is stopped for a certain period of time when the drive state of the drive motor 36 is continued to prevent the electric motor 36 from being burned. For example, when the operation switch 62 is kept pressed and the excitation state of the timer relay coil T1 shown in FIG. 6 continues for a certain time (for example, 20 seconds), the timer relay contact T1 ′ is turned on, the coil RA is excited and the relay contact RA is excited. 'Opens. As a result, the excitation state of the relay coil CT is released, the relay contact CT 'is opened, and the electric motor 36 is stopped.

(3) Storage operation of load receiving table Next, an operation at the time of storing the load receiving table in which the load receiving table 5 is shifted from the posture shown in FIG. 12 to the storage posture shown in FIG. In this case, first, the unfolded load receiving platform 5 is folded in a procedure reverse to the procedure of FIGS. 10 to 12 when the load receiving platform 5 is deployed, and the load receiving platform main body 25 and the load receiving platform tip 27 are leaned against the support roller 12. (See FIG. 10).

  When the operation switch 62 is pressed with the load receiving table body 25 and the load receiving table tip 27 leaning against the support roller 12, the solenoid drive unit 40a is excited through the NC contact of the overlapping relay contact R4 ′, and the lifting operation is performed. Control valve 40 is switched to the communication position. At the same time, the circuit indicated by the arrow A1 is energized, and the relay coils CT and T1 (see FIG. 6) are excited. As a result, the relay contact CT 'is closed and the electric motor 36 is driven. As a result, the lift cylinder 22 extends, the lift arm 30 rotates upward, and the posture of the load receiving body main body 25 gradually lies while rolling on the support roller 12. When the load receiving platform 5 reaches the set angle β during the ascent, the gate sensor 18 is turned on, the relay coils R1 and R5 are excited, and the relay contacts R1 'and R5' are closed. When the relay contact R5 'is closed, the solenoid driving unit 42a is excited, the lowering control valve 42 is opened, the pressure oil supply flow rate to the lift cylinder 22 is reduced, and the rising speed is reduced.

  After that, when it rises to the state of FIG. 9 at a slow speed and the load receiving platform 5 reaches the storage height, the arm sensor 28 (see also FIG. 3) is turned on, the relay coil R2 is excited, and the relay contact R2 ′ is closed. As a result, the relay coil R4 is excited and the relay relay contact R4 ′ is switched from the state of FIG. 5 to the NO-side contact, and the energization destination is changed from the solenoid drive unit 40a to the solenoid drive unit 52a. And the forward movement control valve 52 is opened, and at the same time, the relay circuit R5 is de-energized and the relay contact R5 'is opened, and the lowering control valve 42 is switched to the shut-off position. Since the circuit shown is energized, the relay contact CT ′ is maintained in the closed state, and the electric motor 36 is continuously driven. When the pressure is continuously pressed, the pressure oil from the hydraulic pump 37 is supplied only to the rod side of the slide cylinder 14, the slide cylinder 14 is retracted, the load receiving platform 5 moves forward, and is stored in the lower space of the vehicle body 1. The

  As described above, in the present embodiment, when the load receiving platform 5 is stored, the load receiving until the storage height is reached from the set angle β with respect to the rising speed of the load receiving platform 5 from the ground contact position to the set angle β. The rising speed of the table 5 can be sufficiently reduced. As a result, it is possible to suppress variations due to changes in the viscosity of the hydraulic oil at the height position where the operation is switched from the raising operation to the forward movement, and the positional deviation with respect to the set position (storage height) of the operation switching position is within an allowable range. It is advantageous in storing. Therefore, for example, even when the operation delay of the hydraulic cylinder due to the change in the viscosity of the hydraulic oil becomes large, the load receiving platform 5 can be drawn into the lower space of the vehicle at an appropriate timing. Eventually, it is possible to suppress damage to parts of the load receiving table lifting device and generation of unpleasant noise.

  Further, in the case of the present embodiment, since it can be established only by changing the electric circuit of the load receiving device elevating device having an existing hardware configuration, it is a great merit that the introduction is easy without increasing the number of parts.

  In the present embodiment, the maximum flow rate of the pressure oil discharge pipe 41 is limited by the throttle valve 43. However, the maximum flow rate may be limited by adjusting the diameter of the pressure oil discharge pipe 41. .

  FIG. 15 is a hydraulic circuit diagram showing an example of the configuration of a hydraulic drive device of a retractable load receiving device lifting apparatus according to the second embodiment of the present invention, and FIG. 16 is a retractable system according to the second embodiment of the present invention. FIG. 17 is a timing chart of operation control by the control means of the retractable load receiving table lifting apparatus according to the second embodiment of the present invention. In these drawings, the same parts as those in the above-described drawings are denoted by the same reference numerals as those in the above-mentioned drawings, and the description thereof is omitted.

  The present embodiment is different from the first embodiment in that the pressure oil supplied to the lift cylinder 22 is reduced by reducing the pressure oil supply line to the lift cylinder 22 instead of thinning out the pressure oil. The point is to decelerate the ascending speed.

  As shown in FIG. 15, the difference between the hydraulic circuit and the first embodiment is that a flow rate control valve 64 for controlling the flow rate of the pressure oil flowing in the pressure oil supply line 39 is provided in the pressure oil supply line 39. It is a point. The flow rate control valve 64 is an electromagnetic switching valve having a solenoid drive unit 64a, and a throttle position for reducing the flow rate of the pressure oil flowing through the pressure oil supply pipeline 39 and the switching position (left side in FIG. 15) for opening the pressure oil supply pipeline 39. Position (right side in FIG. 15). The flow rate control valve 64 is normally in the communication position, and is switched to the throttle position only when the load receiving platform 5 is raised from the set angle β to the storage height during the storage operation. The speed ratio of the load receiving table raising speed before and after reaching the set angle β depends on the setting of the throttle amount at the throttle position of the flow rate adjusting valve 64. Other configurations are the same as those of the first embodiment.

  In the case of the present embodiment, the unfolding operation of the load receiving pedestal 5 and the lifting operation of the load receiving pedestal 5 are the same as those in the first embodiment, and thus the description thereof is omitted. Even during the retracting operation, the operation from when the load receiving table body 25 is leaned against the support roller 12 until the load receiving table 5 reaches the set angle β is the same as in the first embodiment. The difference from the first embodiment is that when the gate sensor 18 detects that the load receiving platform 5 has reached the set angle β and the relay contacts R1 ′ and R5 ′ are closed, the solenoid driving unit 64a is excited and the flow rate is increased. The control valve 64 is switched to the throttle position, the supply flow rate of the pressure oil to the lift cylinder 22 is reduced, and the rising speed is reduced as shown in FIG. Thereafter, the circuit operates in the same manner as in the first embodiment when the cargo receiving platform 5 reaches the storage height and then moves to the front storage position.

  Also in the present embodiment, the same effect as that of the first embodiment can be obtained by adding the flow rate adjustment valve 64 slightly. In addition, some hydraulic cylinders are integrated with a flow rate adjusting valve and have a function of adjusting the flow rate of the pressure oil supplied to the hydraulic cylinders. Sixteen hydraulic circuits can be configured. Moreover, the same effect can be acquired by providing in parallel the two flow control valves in which the different flow volume flows into the pressure oil supply pipeline 39, and switching them.

  FIG. 18 is an electric circuit diagram showing an example of the configuration of a hydraulic drive device of a retractable load receiving device lifting apparatus according to the third embodiment of the present invention, and FIG. 19 is a retractable system according to the third embodiment of the present invention. It is a timing chart of the operation control by the control means of the load receiving table lifting device. In these drawings, the same parts as those in the above-described drawings are denoted by the same reference numerals as those in the above-mentioned drawings, and the description thereof is omitted.

  This embodiment is different from the first embodiment in that the drive speed of the hydraulic pump 37 is reduced by reducing the drive speed of the electric motor 36, and the supply flow rate of pressure oil to the lift cylinder 22 is reduced. It is in the point which decelerates the rising speed of the stand 5.

  The electric circuit in the present embodiment shown in FIG. 18 is provided with a controller 65 as a control means, and solenoid drive units 40a, 42a, 50a, 52a of the control valves 40, 42, 50, 52 and electric motors. A command signal to 36 is output by the controller 65 in accordance with a program stored in advance. That is, for example, when the load receiving platform 5 is deployed, for example, if the switch 63 is continuously pressed, the load receiving platform 5 moves rearward from the storage position, and when the detection signal from the rear end sensor 17 is input, it is lowered to the ground position. (Operation from FIG. 8 to FIG. 9 to FIG. 10). Further, during the cargo handling operation, the load receiving platform 5 is moved up and down by operating the switches 62 and 63 (operations of FIGS. 12, 13, and 14).

  On the other hand, if the switch 62 is continuously pressed from the state shown in FIG. 10 during the storing operation of the cargo receiving platform 5, the controller 64 outputs a command signal to the solenoid driving unit 40a to raise the cargo receiving platform 5. Thereafter, when a detection signal from the gate sensor 18 is input, the command signal to the electric motor 36 is changed, and a command signal for instructing to drive at a speed slower than the driving speed of the electric motor 36 during other operations. Is output to the electric motor 36. As a result, the ascending speed of the load receiving platform 5 is slowed as the electric motor 36 is decelerated until the storage height is reached from the set angle β. Thereafter, when a detection signal from the arm sensor 28 is input, the controller 65 stops outputting the command signal to the solenoid drive unit 40a, restores the magnitude of the command signal to the electric motor 36, and returns to the solenoid drive unit. A command signal is output to 52a. Thereby, the goods receiving stand 5 moves to the front storage position and is stored in the lower space of the vehicle.

  The other points are the same as in the first embodiment.

  At this time, the ascending speed of the load receiving platform 5 from the set angle β during the storage operation to the storage height is higher than the ascent speed before reaching the set angle β as in the previous two embodiments. Although it can be set to a slow constant speed, depending on the speed control of the electric motor 36, for example, as shown in FIG. It can also be decreased gradually as it approaches. It is possible to decelerate in steps, or non-linearly or linearly. According to the present embodiment, in addition to the effect that the operation can be switched from the rising of the load receiving platform 5 to the forward movement at an appropriate timing, the degree of freedom of the mode of speed reduction of the load receiving platform 5 is increased in this way. There is a merit.

  When the extension speed of the lift cylinder 22 is adjusted by the controller as in the present embodiment, in addition to a method for controlling the drive speed of the electric motor 36, for example, a proportional electromagnetic control valve is used as the control valve 40 for raising operation. It is also conceivable that the flow rate of the pressure oil flowing through the pressure oil supply line 39 is controlled by the raising operation control valve 40.

  Further, in each of the embodiments described above, it is detected by the rotation angle of the hinge 24 by the gate sensor 18 that the load receiving table 5 has reached the set angle β during the storage operation, and the load receiving table 5 has reached the storage height. This is detected by the arm sensor 28, but the design of the sensor installation mode, the type of sensor used, and the sensing method can be changed as appropriate. For example, a proximity switch is provided in the vicinity of the support roller 12 and an angle sensor is provided at the proximal end of the link arm 30 to detect the shift to the storage operation when the load receiving body 25 is leaned, and then the angle sensor Thus, the setting angle β and the storage height can be detected. Or in each embodiment, it was set as the structure which detects folding of the load receiving stand 5, when the detection signal by the gate sensor 18 of the load receiving stand 5 is output, However, Depending on the case, the attachment method and detection aspect of a sensor are changed. Accordingly, it is possible to adopt a configuration in which folding is detected when the detection signal from the gate sensor 18 is interrupted. The electric circuit can be appropriately configured according to the type of sensor and the detection mode, and the same effect can be obtained in these cases.

  Further, in the above description, the case where the present invention is applied to the load receiving platform lifting device having the load receiving platform 5 that can be folded into three sheets has been described as an example. The invention is applicable and can achieve the same effect.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view showing an overall structure of a vehicle equipped with a retractable load receiving table lifting apparatus according to a first embodiment of the present invention. It is a perspective view showing the detailed structure of the retractable cradle lifting device of the present invention at the time of storage. It is a perspective view showing the detailed structure of the retractable load receiving table raising / lowering device of the present invention at the time of deployment. It is a hydraulic circuit diagram showing the example of 1 composition of the hydraulic drive with which the retractable load receiving device raising and lowering device concerning the 1st embodiment of the present invention was equipped. It is an electric circuit diagram showing the principal part structure regarding the drive control of the retractable load receiving table raising / lowering device according to the first embodiment of the present invention. It is an electric circuit diagram showing the principal part structure regarding the drive control of the retractable load receiving table raising / lowering device according to the first embodiment of the present invention. It is a timing chart of the operation control by the control means of the retractable cargo receiver lifting device according to the first embodiment of the present embodiment. It is operation | movement explanatory drawing of the retractable receiving stand raising / lowering apparatus which concerns on the 1st Embodiment of this invention. It is operation | movement explanatory drawing of the retractable receiving stand raising / lowering apparatus which concerns on the 1st Embodiment of this invention. It is operation | movement explanatory drawing of the retractable receiving stand raising / lowering apparatus which concerns on the 1st Embodiment of this invention. It is operation | movement explanatory drawing of the retractable receiving stand raising / lowering apparatus which concerns on the 1st Embodiment of this invention. It is operation | movement explanatory drawing of the retractable receiving stand raising / lowering apparatus which concerns on the 1st Embodiment of this invention. It is operation | movement explanatory drawing of the retractable receiving stand raising / lowering apparatus which concerns on the 1st Embodiment of this invention. It is operation | movement explanatory drawing of the retractable receiving stand raising / lowering apparatus which concerns on the 1st Embodiment of this invention. It is a hydraulic circuit diagram showing the example of 1 structure of the hydraulic drive device of the retractable load receiving table raising / lowering device which concerns on the 2nd Embodiment of this invention. It is an electric circuit diagram showing the principal part structure regarding the drive control of the retractable load receiving device raising / lowering device which concerns on the 2nd Embodiment of this invention. It is a timing chart of the operation control by the control means of the retractable cradle lifting device according to the second embodiment of the present invention. It is an electric circuit diagram showing the principal part structure regarding the drive control of the retractable load receiving device raising / lowering device which concerns on the 3rd Embodiment of this invention. It is a timing chart of the operation control by the control means of the retractable cradle lifting device according to the third embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Car body 4 Retractable load receiving device raising / lowering device 5 Load receiving table 8 Guide rail 12 Support roller 13 Support arm 14 Slide cylinder 18 Gate sensor 22 Lift cylinder 23 Load receiving base end portion 25 Load receiving base main body 28 Arm sensor 29 Slide unit 30 Lift arm 36 Electric motor 37 Hydraulic pump 38 Hydraulic oil tank 39 Pressure oil supply line 40 Lifting operation control valve 41 Pressure oil discharge line 42 Lowering operation control valve 43 Throttle valve 50 Backward movement control valve 52 Frontward movement control valve 64 Flow control valve 65 Controller R1-5 Relay coil R1'-5 ', R2 "Relay contact

Claims (6)

A load receiving base having a load receiving base base end and a load receiving base main body folded over thereto, a guide rail provided at a lower portion of the vehicle, a slide unit capable of traveling along the guide rail, and the slide unit back and forth A slide cylinder for sliding, a lift arm for connecting the load receiving base to the slide unit so as to be movable up and down, and a lift cylinder for moving the load receiving base up and down, and is folded when the load receiving base is raised to a storage height. In the retractable load receiving device lifting device for sliding the load receiving table forward and storing the load receiving table in the space on the lower side of the vehicle,
Arm angle detection means for detecting the angle of the lift arm;
Folding detection means for detecting the folded state of the load receiving table;
Based on the signals from the arm angle detection means and the folding detection means, the load receiving platform is set to a predetermined set angle set within an angle range until the storage platform is being stored and the storage height is reached. Control means for detecting that the platform has reached and decelerating the speed from reaching the set angle to the retracted height with respect to the drive speed of the lift cylinder before reaching the set angle; A retractable cargo receiving device lifting device characterized by comprising: The retractable load receiving device lifting apparatus according to claim 1,
A hydraulic pump for discharging pressure oil to be supplied to the slide cylinder and the lift cylinder;
A pressure oil supply line connecting the lift cylinder and the hydraulic pump;
A control valve for raising operation for communicating or blocking the pressure oil supply pipeline;
A pressure oil discharge line branched from the pressure oil supply line and connected to a hydraulic oil tank;
A control valve for lowering operation for communicating or blocking the pressure oil discharge pipe line,
The control means opens the raising operation control valve to start the storing operation of the load receiving table, and the raising operation is performed after the load receiving table reaches the set angle until it reaches the storing height. A retractable load receiving table elevating device, wherein in addition to the control valve, the lowering control valve is opened to return a part of the pressure oil supplied to the lift cylinder to the hydraulic oil tank.   3. The retractable cargo receiving platform lifting / lowering device according to claim 2, wherein the throttle valve is provided in the pressure oil discharge pipe and limits a maximum flow rate of the pressure oil returned to the hydraulic oil tank among the pressure oil supplied to the lift cylinder. A retractable cradle raising and lowering device characterized by comprising: The retractable load receiving device lifting apparatus according to claim 1,
A hydraulic pump for discharging pressure oil to be supplied to the slide cylinder and the lift cylinder;
A pressure oil supply line connecting the lift cylinder and the hydraulic pump;
A control valve for raising operation for communicating or blocking the pressure oil supply pipeline;
A flow rate control valve for controlling the flow rate of the pressure oil flowing through the pressure oil supply line,
The control means opens the raising operation control valve to start the storing operation of the load receiving table, and the flow rate control is performed after the load receiving table reaches the set angle until it reaches the storing height. A retractable cradle raising and lowering device characterized in that a supply flow to the lift cylinder is reduced by a valve. The retractable load receiving device lifting apparatus according to claim 1,
A hydraulic pump for discharging pressure oil to be supplied to the slide cylinder and the lift cylinder;
A pressure oil supply line connecting the lift cylinder and the hydraulic pump;
A control valve for raising operation for communicating or blocking the pressure oil supply pipeline;
An electric motor for driving the hydraulic pump,
The control means opens the raising operation control valve to start the storage operation of the load receiving table, and the electric motor during a period from when the load receiving table reaches the set angle until the storage height is reached. Retractable load receiving device elevating device, characterized in that the driving speed is reduced. In any one of Claims 1-5,
A support arm protruding rearward of the slide unit;
A support roller that is rotatably provided at a rear end portion of the support arm, and a load receiving base body portion that is folded with respect to a base end portion of the load receiving stand is in rolling contact with the support arm;
The arm angle detection means is a proximity switch provided on the support arm so as to face the lift arm having the storage height.
The folding detection means is an angle sensor that is provided on a hinge that connects a base end portion of the load receiving base and a main body portion, and detects an angle of the load receiving base main body portion with respect to the load receiving base base end portion,
The control means detects that the load receiving table has reached a set angle based on an angle of the load receiving table main body that rolls in contact with the support roller and lies down horizontally as the lift arm is raised during the storing operation. Then, the retractable load receiving device lifting / lowering device is characterized in that it is detected by the detection signal of the arm angle detecting means that the load receiving table has reached the storage height.

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