JP2019172207A - Cargo receiving platform lifting device - Google Patents

Abstract

To precisely set the angle of a cargo receiving platform to a reference angle.SOLUTION: The present invention relates to a cargo receiving platform lifting device comprising: a lift arm 2 which can rotate upward and downward relative to a vehicle; a cargo receiving platform 3 which is coupled to a front end of the lift arm upward and downward rotatably; a lift cylinder 4 which rotates the lift arm upward and downward; a tilt cylinder 5 which rotates the cargo receiving platform upward and downward relative to the lift arm; a tilt sensor 8 which measures a tilt of the cargo receiving platform based upon a gravitational direction; and an attachment member 10 which attaches the tilt sensor to the cargo receiving platform. The attachment member 10 comprises: a pin 11 which extends in an extension direction of an axis P2 of rotation of the cargo receiving platform to serve as the center O of rotation of the tilt sensor for the cargo receiving platform; a guide hole 12 which is an arcuate long hole having its center at the center O of rotation; and a fixture 13 which is inserted into the guide hole to fix the tilt sensor to the cargo receiving platform.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a load receiving table lifting device that lifts and lowers a load receiving table by a parallel link, and more particularly to a load receiving table lifting device that raises and stores a load receiving table.

  Some load receiving platform lifting / lowering devices support a cargo handling operation by moving an arm (parallel link) up and down relative to a vehicle load platform so that the load receiving table attached to the arm moves in parallel up and down. As this type of load receiving table lifting device, there is known a device that includes a tilt cylinder that rotates the load receiving table with respect to an arm, and stores the load receiving stand upright along the rear surface of the load receiving plate (see Patent Document 1, etc.). ). In the load receiving platform lifting apparatus of the same document, the detection target (sensing plate) provided in the tilt cylinder is detected by a proximity switch, and the level of the load receiving stand is estimated by detecting a predetermined stroke of the tilt cylinder.

JP 2005-238865 A

  In addition to the typical work of raising and lowering the cargo cradle between the ground and the cargo bed, there are various forms of cargo handling work using the cargo cradle. For example, when the delivery location of luggage is higher than the ground surface (ground) of the vehicle (wheel), a bridge is built between the delivery platform and the delivery location in order to move the cart between the delivery location and the delivery platform. There is. Patent Document 1 also shows that when the delivery location is lower than the loading platform, the tilt cylinder is driven to tilt (reverse tilt) the loading platform, and the delivery location and the loading platform are connected by an inclined loading platform.

  Here, the load receiving table lifting device including the tilt cylinder may be provided with an interlock function in which the lift cylinder cannot be driven unless the load receiving table is at a reference angle (for example, horizontal). In the case where the load receiving platform is inclined and used as in the above example, it is necessary to once return the load receiving platform to the reference angle in order to move up and down. However, in the configuration in which the proximity of the load receiving table is detected using a proximity sensor as in Patent Document 1, a certain size is required for the detection target in order to ensure the operation of the proximity switch. Therefore, there is a deviation corresponding to the size of the object to be detected in the timing when the proximity switch is operated between when returning the load receiving table to the reference angle by the backward tilting operation and when returning it by the forward tilting operation. It ’s difficult.

  An object of the present invention is to provide a load receiving table lifting device capable of accurately setting the angle of the load receiving table to a reference angle.

  In order to achieve the above object, the present invention provides a lift arm that can be turned up and down with respect to a vehicle, a load receiving base that is pivotally connected to the tip of the lift arm, and a lift arm that moves up and down. A lift cylinder that rotates, a tilt cylinder that rotates the load receiving table up and down with respect to the lift arm, an inclination sensor that measures the inclination of the load receiving table with respect to the direction of gravity, and the tilt sensor on the load receiving table A load receiving platform lifting device including a mounting member, wherein the mounting member extends in a direction in which a rotation shaft of the load receiving table extends and serves as a rotation center of the tilt sensor with respect to the load receiving table, A guide hole that is an arc-shaped long hole centered on the rotation center; and a fixture that is inserted into the guide hole and fixes the tilt sensor to the load receiving base.

  Unlike a proximity switch or the like used in pair with a sensing plate, the tilt sensor can measure its own absolute angle with respect to the direction of gravity, and there is almost no error in measured values during forward tilting and backward tilting operations. According to the present invention, by providing a tilt sensor on the load receiving table, the absolute angle of the load receiving table based on the direction of gravity can be measured with high accuracy at all times regardless of the posture of the vehicle (tilting of the ground plane). The angle of the receiving platform can be accurately set to the reference angle. In addition, the mounting member for attaching the tilt sensor to the load receiving table has an arcuate guide hole, so that the mounting angle of the tilt sensor with respect to the load receiving table can be adjusted in the tilt direction of the load receiving table around the pin. . By adjusting the angle of the tilt sensor, the reference angle of the load receiving table with respect to the output of the tilt sensor can be mechanically and flexibly adjusted. For example, when the tilt sensor is tilted backward with respect to the load receiving platform, the load receiving platform (reference angle) at the same output value of the tilt sensor is tilted forward by that amount.

The perspective view showing a mode that the consignment raising / lowering apparatus which concerns on one Embodiment of this invention was attached to the vehicle. The side view of the cargo receiving stand raising / lowering apparatus which concerns on one Embodiment of this invention. 2 is a left side view of the base of the load receiving table provided in the load receiving table lifting device of FIG. The bottom view of the base of the load receiving table provided in the load receiving table lifting device of FIG. Enlarged view of part V in FIG. Enlarged view of the tilt sensor mounting part of the receiving platform Side view of bracket to install tilt sensor Top view of the bracket for mounting the tilt sensor Rear view of bracket for mounting tilt sensor Hydraulic circuit diagram of the drive system provided in the load receiving table lifting device of FIG. FIG. 2 is an electric circuit diagram of a drive system provided in the cargo cradle lifting device of FIG. The flowchart showing the instruction | command output procedure to the drive device of the load receiving stand by the control apparatus with which the load receiving stand raising / lowering apparatus of FIG. 2 was equipped. The flowchart showing the setting procedure of the interlock by the control apparatus with which the load receiving table raising / lowering apparatus of FIG. 2 was equipped.

  Embodiments of the present invention will be described below with reference to the drawings.

-Loading platform lifting device-
FIG. 1 is a perspective view illustrating a state in which a load receiving platform lifting apparatus according to an embodiment of the present invention is attached to a vehicle, and FIG. 2 is a side view of the load receiving platform lifting apparatus. In the present specification, front and rear are defined with reference to a vehicle. In other words, the front direction (the diagonally upper left direction in FIG. 1) of the driver's seat (not shown) of the vehicle is the front. 1 and 2 is a device that supports a cargo handling operation by raising and lowering the load receiving table by means of parallel links, and is a kind of device for standing and storing the load receiving table. The load receiving platform lifting device includes a support frame 1, left and right lift arms 2, a load receiving stand 3, left and right lift cylinders 4, left and right tilt cylinders 5 (FIG. 2), and a drive system 6 (FIGS. 10 and 11). Yes.

  In the present embodiment, the drive device that drives the load receiving platform 3 includes two hydraulic cylinders. The lift cylinder 4 is a first cylinder that raises and lowers the load receiving table 3, and the tilt cylinder 5 is a second cylinder that tilts the load receiving table 3. The lift cylinder 4 that is the first cylinder is mainly used during the cargo handling operation, and the tilt cylinder 5 that is the second cylinder is used when the cargo receiving platform 3 is stored (shifted to the storage position). Although the lift cylinder 4 and the tilt cylinder 5 may be double-acting, a single-acting hydraulic cylinder is used in this embodiment. Next, components of the load receiving table lifting device, specifically, the connection relationship between the support frame 1, the lift arm 2, the load receiving stand 3, the lift cylinder 4, and the tilt cylinder 5 will be described.

  First, the support frame 1 is a base structure of the apparatus for attaching the load receiving platform lifting apparatus to the vehicle, and is attached to the lower side of the rear part of the vehicle frame (chassis frame) of the vehicle. Bumpers B <b> 1-B <b> 3 extending to the left and right are attached to the rear end surface of the support frame 1. The bumpers B1-B3 are arranged side by side, and a predetermined interval is interposed between the central bumper B1 and the left and right bumpers B2, B3 so as to pass the left and right lift arms 2 rotating up and down. .

  The lift arm 2 is a member that rotates up and down with respect to the vehicle, and is connected to the support frame 1 via a tilt arm 7. The upper end of the tilt arm 7 is connected to the support frame 1 via a pin P0 extending left and right, and is rotatable with respect to the support frame 1 around the pin P0. The base end portion (front end portion) of the lift arm 2 is connected to the tilt arm 7 via a pin P1 extending left and right at a position below the pin P0. The lift arm 2 is rotatable with respect to the tilt arm 7 about the pin P1. The front end portion (rear end portion) of the lift arm 2 is connected to the upper portion of the base end portion of the load receiving platform 3 via a pin P2 extending in the left-right direction. That is, the load receiving platform 3 is connected to the tip of the lift arm 2 so as to be rotatable up and down around the pin P2.

  The tilt cylinder 5 is a hydraulic cylinder that rotates (tilts) the load receiving table 3 up and down with respect to the lift arm 2. A base end portion (front end portion) of the tilt cylinder 5 is connected to the support frame 1 via a pin P3 extending left and right at a position below the pin P1. The tilt cylinder 5 is rotatable with respect to the support frame 1 around the pin P3. The tip end portion (rear end portion) of the tilt cylinder 5 is connected to the lower portion of the base end portion of the load receiving platform 3 via a pin P4 extending in the left-right direction. The tilt cylinder 5 and the load receiving platform 3 are relatively rotatable about the pin P4.

  The lift cylinder 4 is a hydraulic cylinder that moves the lift arm 2 up and down to raise and lower the load receiving platform 3. The base end portion (front end portion) of the lift cylinder 4 is connected to the tilt arm 7 via a pin P5 extending left and right at a position below the pin P3. The lift cylinder 4 is rotatable with respect to the tilt arm 7 about the pin P5. A front end portion (rear end portion) of the lift cylinder 4 is connected to a lower portion near the front end of the lift arm 2 via a pin P6 extending in the left-right direction. The lift cylinder 4 and the lift arm 2 are relatively rotatable about the pin P6.

  Here, the tilt cylinder 5 also serves as a link arm that forms a parallel link together with the tilt arm 7 and the lift arm 2. For example, in FIG. 2, when the tilt cylinder 5 contracts and the load receiving platform 3 becomes horizontal (two-dot chain line 3a), the pin P4 moves to the position X. In a state where the pin P4 is at the position X and the load receiving table 3 is not grounded, the quadrangle having the pins P1 to P4 as apexes is configured as a parallelogram. When the lift cylinder 4 expands and contracts in a state where the pins P1 to P4 form the apex of the parallelogram, the lift arm 2 and the tilt cylinder 5 rotate around the pins P1 and P3 as fulcrums and rotate as indicated by an arrow b, The load receiving platform 3 translates up and down. However, when the lift cylinder 4 is further contracted after the load receiving platform 3 is grounded (two-dot chain line 3b), the tilt arm 7 rotates backward (counterclockwise in FIG. 2) around the pin P0 as a fulcrum as shown by an arrow c. To do. As a result, the pin P1 attached to the tilt arm 7 moves backward relative to the pin P3 attached to the support frame 1 (the lift arm 2 moves backward relative to the tilt cylinder 5), and the tip is grounded. The load receiving platform 3 tilts backward as indicated by an arrow d up to (two-dot chain line 3c).

  When the tilt cylinder 5 is expanded and contracted, the load receiving table 3 rotates with the pin P2 as a fulcrum with respect to the lift arm 2 as shown by an arrow a. If the tilt cylinder 5 is extended when the load receiving platform 3 is at the height of the floor surface of the loading platform A, the load receiving platform along the rear surface of the loading platform A of the vehicle as shown by the solid line in FIG. 2 (see also FIG. 1). 3 stands up and shifts to the retracted position. On the other hand, if the tilt cylinder 5 is contracted, the load receiving platform 3 in the retracted position can be expanded to a reference angle (for example, horizontal) and can be used for cargo handling work.

-Tilt sensor-
FIG. 3 is a left side view of the base of the load receiving table 3, and FIG. 4 is a bottom view (a diagram showing a left side portion of the surface opposite to the load receiving surface in the base of the load receiving table 3). As shown in these drawings, the load receiving platform 3 is provided with an inclination sensor 8. The tilt sensor 8 is a sensor that measures the tilt angle of the load receiving platform 3, and for example, a gyro sensor can be used. However, in addition to the gyro sensor, a pendulum type or float type inclination sensor (a sensor that detects the inclination of the load receiving table 3 with respect to a suspended weight or a liquid surface), an acceleration sensor, an inertial sensor, or the like may be used as the inclination sensor 8. it can.

  The part of the load receiving stand 3 where the inclination sensor 8 is installed is, for example, at least one of the left and right (left side in this example) stiffener 3A. The stiffener 3A in the present embodiment is a hollow member, and one stiffener is provided in each of the left and right regions of the lower surface of the load receiving platform 3 (the surface opposite to the load receiving surface and facing rearward when stored). Assuming that the load receiving surface of the load receiving table 3 is horizontal, the stiffener 3A has a long and narrow triangular shape when viewed from the left and right, the upper surface is horizontal, and the thickness is toward the rear (the tip of the load receiving table 3). It is getting thinner. In this embodiment, the inclination sensor 8 is accommodated in a relatively wide front portion (portion on the base side of the load receiving platform 3) inside the stiffener 3A. The wiring of the tilt sensor 8 is also passed inside the stiffener 3A.

  FIG. 5 is an enlarged view of a portion V in FIG. 3, and FIG. 6 is an enlarged view of a tilt sensor mounting portion of the load receiving table 3. 7 to 9 are three views of the bracket for attaching the tilt sensor 8 to the load receiving platform 3, FIG. 7 is a side view of the bracket, FIG. 8 is a plan view, and FIG. 9 is a rear view. The inclination sensor 8 is attached to the load receiving platform 3 via an attachment member 10. The attachment member 10 includes a pin 11, a guide hole 12, and a fixture 13, which will be described later, as main elements.

  In the present embodiment, the bracket 14 is attached to the inclination sensor 8 for the purpose of mating with the cargo receiver 3. The bracket 14 is formed by bending a flat plate into an L shape as shown in FIGS. 7 to 9, and includes a mounting plate portion 14 </ b> A and a sensor mounting plate portion 14 </ b> B for the load receiving platform 3. The mounting plate part 14A is a part for contact with the cargo receiving platform 3, and the sensor mounting plate part 14B is a part for mounting the inclination sensor 8. The angle formed by the mounting plate portion 14A and the sensor mounting plate portion 14B is a right angle in this embodiment. The mounting plate portion 14A is provided with two through holes (burst holes) H1 and H2, and nuts N1 and N2 are welded corresponding to the through holes H1 and H2. The nuts N1 and N2 are provided on the surface opposite to the contact surface of the mounting plate portion 14A with the load receiving platform 3 (the side where the sensor mounting plate portion 14B exists). The sensor mounting plate portion 14B is provided with two through-holes (burst holes) H3 and H4, and the tilt sensor 8 is formed by bolts B3 and B4 and nuts N3 and N4 (FIG. 5) passed through these through-holes H3 and H4. The sensor mounting plate portion 14B is fixed to. In the present embodiment, the inclination sensor 8 is mounted on the surface on the side where the mounting plate portion 14A is present with respect to the sensor mounting plate portion 14B in the present embodiment, but may be mounted on the opposite surface. .

  On the other hand, in the joint portion with the bracket 14 on the load receiving platform 3 side (in this embodiment, the vertical inner wall surface of the stiffener 3A), as shown in FIG. 6, the fulcrums correspond to the through holes H1 and H2 of the bracket 14, respectively. A hole 15 and the guide hole 12 are provided. The pin 11 is inserted into the fulcrum hole 15 and the through hole H1. The pin 11 serves as a rotation center of the tilt sensor 8 with respect to the load receiving platform 3. Further, the pin 11 extends in the left-right direction (the extending direction of the pin P2 that is the rotation axis of the load receiving table 3), and the tilt sensor 8 rotates the load receiving table 3 with respect to the load receiving table 3 around the pin 11. It is configured to rotate in a direction (that is, in a vertical plane extending in the front-rear direction). The guide hole 12 is an arc-shaped long hole centering on the rotation center O of the tilt sensor 8 in the fulcrum hole 15, and the fixing tool 13 is inserted into the guide hole 12 and the through hole H2. The radius of the arc drawn by the center line of the guide hole 12 is equal to the center-to-center distance L2 of the pin 11 and the fixture 13. In this embodiment, the bolt 11 is used for the pin 11 and the fixing tool 13, and the pin 11 and the fixing tool 13 are inserted from the outside of the stiffener 3 </ b> A, and tightened to the nuts N <b> 1 and N <b> 2 of the bracket 14, respectively. It is fixed to the cargo receiving table 3 through 14. The inclination sensor 8 can be rotated around the pin 11 by loosening the pin 11 and the fixture 13 which are bolts. The angle of the tilt sensor 8 can be adjusted within the movable range of this mechanism (the range of the central angle α of the guide hole 12).

  At this time, a recess 12A is formed in the outer peripheral portion or inner peripheral portion (in the present embodiment, the inner peripheral portion) of the arc of the guide hole 12. The fulcrum hole 15 has a distance L1 (about the depth of the recess 12A) from the arc center (rotation center O) of the guide hole 12 to the recess direction of the recess 12A (in this embodiment, inward in the radial direction of the arc of the guide hole 12). It is a long hole that extends only in a straight line. In other words, the recess 12A is located on the extension line of the fulcrum hole 15 (on the extension line of the long axis of the opening shape of the fulcrum hole 15). Further, the fixture 13 can be inserted into the recess 12A by shifting the tilt sensor 8 to the inside of the arc of the guide hole 12 by aligning the fixture 13 with the recess 12A. This is because the fulcrum hole 15 is a long hole, and the pin 11 is allowed to move in the direction of the depression 12A. In the present embodiment, the angle of the load receiving platform 3 formed with respect to the load receiving platform 3 (load receiving surface) in a state where the fixing tool 13 enters the recess 12 </ b> A is set as a standard angle β for the mounting angle of the inclination sensor 8. In this embodiment, the inclination sensor 8 is inclined by 45 ° relative to the load receiving table 3 (load receiving surface) in the case of the standard angle β, and when the load receiving table 3 stands up, the inclination sensor 8 is 45 °, and the load receiving table 3. -45 ° is output when becomes horizontal. As a result, even an inexpensive inclination sensor having an angle measurement range of only about 90 ° can monitor the angle of the load receiving platform 3 from horizontal to standing. In this embodiment, the recess 12A is positioned at the midpoint of the arc drawn by the guide hole 12, and the angle can be adjusted by α / 2 on both sides of the recess 12A.

-Drive system-
The drive system 6 is accommodated in a unit box 9 (FIG. 1) attached to one side of the support frame 1 in the left-right direction (left side in the present embodiment). The unit box 9 is also provided with a storage space for an operating device 30 (FIG. 11) for operating the load receiving table lifting device. The drive system 6 is a system that drives the lift cylinder 4 and the tilt cylinder 5. The operation device 30 is a wired operation type remote controller having a connector 35 (FIG. 11). The operating device 30 can be connected to a connector 50 (FIG. 11) disposed inside the unit box 9 and used on the ground, or connected to a connector (not shown) disposed inside the loading platform A. It can also be used on the loading platform A (in the packing box) or on the loading platform 3. A wirelessly operated remote control may be used as an operating device. In the following description, a case where the operation device 30 is operated as a representative will be described as an example as appropriate, but the operation of the load receiving platform lifting device when another operation device is used is also the same.

(Hydraulic circuit)
FIG. 10 is a hydraulic circuit diagram of the drive system 6. As shown in the figure, the load receiving table lifting device includes a hydraulic oil tank 21, a hydraulic pump 22, a motor 23, and switching valves V1-V6. The hydraulic pump 22 sucks the hydraulic oil stored in the hydraulic oil tank 21 and discharges it to the pump oil passage L22. As shown in FIG. 11 later, the motor 23 is connected to a power source BT (for example, a vehicle battery) via a contactor relay CT, and is driven by power supply from the power source BT to drive the hydraulic pump 22. A relief valve RV is provided in the pump oil passage L22, and the maximum value of the pressure in the pump oil passage L22 is defined by the relief valve RV.

  The pump oil passage L22 is connected to the oil passage L4 via the check valve C1, and the oil chamber of the lift cylinder 4 and the hydraulic pump 22 are connected via the pump oil passage L22 and the oil passage L4. The oil passage L4 is provided with a switching valve V1 for ascending operation. The switching valve V1 is a normally closed type electromagnetically driven on-off valve. In a normal state (in a demagnetized state), the oil passage L4 is shut off by a check valve, but opens when the solenoid S1 is excited. L4 is opened.

  A tank oil passage LT1 connected to the hydraulic oil tank 21 is branched from the oil passage L4 at a position between the switching valve V1 and the pump oil passage L22. The tank oil passage LT1 is provided with a switching valve V2 for lowering operation. The switching valve V2 is a normally closed type electromagnetically driven on / off valve. In a normal state (in a demagnetized state), the tank oil passage LT1 is blocked by a check valve, but opens when the solenoid S2 is excited. The oil passage LT1 is opened.

  In the present embodiment, the operation of the lift cylinder 4 is controlled by the switching valves V1 and V2 and the switching valve V5 described later. However, the lift cylinder 4 may be controlled by one three-position switching valve. it can. A throttle valve TV1 is provided on the downstream side of the switching valve V2 in the tank oil passage LT1. A variable throttle is used for the throttle valve TV1, but it may be changed to a fixed throttle if the flow rate adjustment function is unnecessary.

  The pump oil passage L22 is also connected to the oil chamber of the tilt cylinder 5 through the oil passage L5. The inlet of the oil passage L <b> 5 (the branch portion from the pump oil passage L <b> 22) is between the switching valve V <b> 1 and the hydraulic pump 22. A switching valve V3 for forward tilting operation is provided in the oil passage L5. The switching valve V3 is a normally closed type electromagnetically driven on / off valve. In a normal state (in a demagnetized state), the check valve shuts off the flow of hydraulic oil to the tilt cylinder 5 in the oil passage L5. When S3 is excited, it opens and opens the oil passage L5.

  At the position between the switching valve V3 and the tilt cylinder 5, a switching valve V6 is provided in the oil passage L5. The switching valve V6 is a normally closed type electromagnetic direction switching valve, and allows the hydraulic oil to be discharged from the tilt cylinder 5 when the solenoid S6 is excited. On the contrary, when the solenoid S6 is demagnetized, the switching valve V6 allows the hydraulic oil to be supplied to the tilt cylinder 5 by the check valve and prohibits the hydraulic oil from being discharged from the tilt cylinder 5.

  At a position between the switching valves V3 and V6, a tank oil passage LT2 connected to the hydraulic oil tank 21 is branched from the oil passage L5. A switching valve V4 for backward tilting operation is provided in the tank oil passage LT2. The switching valve V4 is a normally closed type electromagnetically driven on / off valve. In a normal state (in a demagnetized state), the tank oil passage LT2 is shut off by a check valve, but opens when the solenoid S4 is excited. The oil passage LT2 is opened.

  In this embodiment, the operation of each tilt cylinder 5 is controlled by three switching valves V3, V4, and V6. However, the tilt cylinder 5 may be controlled by one three-position switching valve. A throttle valve TV2 is provided on the downstream side of the switching valve V4 in the tank oil passage LT2. A variable throttle is used for the throttle valve TV2, but a fixed throttle may be used if the flow rate adjustment function is unnecessary.

  A tank oil passage LT3 connected to the hydraulic oil tank 21 is branched from the oil passage L4 at a position between the switching valve V1 for ascending operation and the lift cylinder 4. The tank oil passage LT3 branches from the oil passage L4, bypasses the tank oil passage LT1, and is connected to the hydraulic oil tank 21 via the throttle valve TV2 and the tank oil passage LT2. That is, the oil chamber of the lift cylinder 4 and the hydraulic oil tank 21 are connected to the hydraulic oil tank 21 via the tank oil path LT1 that is the first tank pipe line, and the tank oil path LT3 that is the second tank oil path. Is connected to the hydraulic oil tank 21. A tank oil passage LT3, which is the second tank oil passage, is provided with a second switching valve V5 for lowering operation. The switching valve V5 is a normally closed type electromagnetically driven on / off valve. In a normal state (in a demagnetized state), the tank oil passage LT3 is blocked by a check valve, but opens when the solenoid S5 is excited. The oil passage LT3 is opened.

  The tank oil passage LT3 is provided with a grounding sensor 24 at a position between the switching valve V5 and the lift cylinder 4. The grounding sensor 24 is a detector that detects the grounding of the cargo receiving platform 3, and a pressure sensor is used in this embodiment. When the load receiving platform 3 comes in contact with the ground, the pressure in the oil chamber of the lift cylinder 4 is reduced as compared to when the load receiving platform 3 is lowered. The pressure in the oil chamber of the lift cylinder 4 is detected by the ground sensor 24, and the detected value is compared with a preset value by, for example, a control device (FIG. 11). Grounding can be detected. Since the ground sensor 24 only needs to be able to measure the pressure in the oil chamber of the lift cylinder 4, it can also be provided at a position between the switching valve V1 and the lift cylinder 4 in the oil passage L4. In addition, for example, an angle sensor that detects the rotation angle of the pins P1, P3, and P5 and a stroke sensor (proximity sensor or distance meter) that detects the stroke of the lift cylinder 4 can also be used as the ground sensor. An inclination sensor or a proximity sensor that detects the inclination angle of the lift arm 2 or the lift cylinder 4 can also be used as a ground sensor.

(electric circuit)
FIG. 11 is an electric circuit diagram of the drive system 6. As shown in the figure, the load receiving platform elevating device includes an operation device (wired remote control) 30, a control panel (microcomputer board) 40, and connectors 50, 60, and 70. A wireless operation type operation device can also be used, but is not shown in the figure. The connector 50 is for normal operation and is connected to a control device 41 (described later). The connectors 60 and 70 are for emergency operation, and are directly connected to the drive system of the drive device (the lift cylinder 4, the tilt cylinder 5 and the motor 23), bypassing the control device 41. The connectors 60 and 70 can be provided in the unit box 9, for example, but the layout can be changed as appropriate. Although the connection relationship between the connectors 60 and 70 will be described later, the first emergency operation connector 60 is directly connected to the drive system of the lift cylinder 4 and the motor 23. The drive system of the lift cylinder 4 includes an ascending drive system and a descending drive system. The ascending drive system includes a switching valve V1 that connects the lift cylinder 4 to the hydraulic pump 22, and the descending drive system includes switching valves V1, V2, and V5 that connect the lift cylinder 4 to the hydraulic oil tank 21. The second emergency operation connector 70 is directly connected to the tilt cylinder 5 and the drive system of the motor 23. The drive system of the tilt cylinder 5 includes a forward tilt drive system and a rear tilt drive system. The forward tilt drive system includes a switching valve V3 that connects the tilt cylinder 5 to the hydraulic pump 22, and the rear tilt drive system includes switch valves V4 and V6 that connect the tilt cylinder 5 to the hydraulic oil tank 21. The drive system of the motor 23 includes a contactor relay CT that drives the motor 23 by connecting it to the power source BT.

  As described above, the operation device 30 is a wired operation type remote controller, and has a connector 35 in addition to an operation unit provided with three push button buttons (upper switch 31, lower switch 32, and open / close switch 33). . The upper switch 31 is operated when instructing to raise the load receiving table 3 (extension of the lift cylinder 4), and the lower switch 32 is operated to instruct lowering of the load receiving table 3 (contraction of the lift cylinder 4). The open / close switch 33 is a button for switching the operation target of the upper switch 31 and the lower switch 32 from the lift cylinder 4 to the tilt cylinder 5. In this embodiment, when instructing the closing operation of the load receiving platform 3 (extension of the tilt cylinder 5), the opening / closing switch 33 and the upper switch 31 are simultaneously operated to instruct the opening operation of the receiving platform 3 (contraction of the tilt cylinder 5). To do so, the open / close switch 33 and the lower switch 32 are operated simultaneously. The opening operation of the load receiving platform 3 refers to an operation of tilting the load receiving platform 3 forward, that is, rotating counterclockwise when viewed from the left side, and the closing operation of the load receiving platform 3 is tilted backward, that is, leftward. Rotating clockwise (clockwise) when viewed from the side.

  The connector 35 of the operating device 30 includes four terminals (A terminal, B terminal, C terminal, and D terminal). This connector 35 can alternatively be connected to either the normal operation connector 50 or the emergency operation connectors 60 and 70. The connectors 50, 60, 70 are also provided with four terminals (A terminal, B terminal, C terminal, and D terminal) corresponding to the connector 35 of the operating device 30. For example, when the connector 35 is connected to the connector 50, the A terminals of the connectors 35 and 50, the B terminals, the C terminals, and the D terminals are connected. Similarly, when the connector 35 is connected to the connector 60, the A terminals, the B terminals, the C terminals, and the D terminals of the connectors 35 and 60 are connected. When the connector 35 is connected to the connector 70, the A terminals of the connectors 35 and 70, the B terminals, the C terminals, and the D terminals are connected. A terminal of the connector 35 of the operating device 30 is connected to the primary side of the upper switch 31, the lower switch 32, and the open / close switch 33. The B terminal of the connector 35 is connected to the secondary side of the lower switch 32, the C terminal is connected to the secondary side of the upper switch 31, and the D terminal is connected to the secondary side of the open / close switch 33.

  The control panel 40 includes a control device (microcomputer) 41 and terminals 42a-42v. The control device 41 is an arithmetic processing device that controls the drive devices (the lift cylinder 4 and the tilt cylinder 5) mainly based on signals from the tilt sensor 8, the ground sensor 24, and the operation device 30, and controls the posture of the load receiving platform 3. is there. The control device 41 controls the cargo cradle 3 with appropriate operation of a mode switch 25, an interlock release switch 26, and an angle setting switch 27 described later. The function of the control device 41 will be described later.

  Terminals 42 a to 42 v are input terminals or output terminals of the control panel 40. Of these, the terminals 42 a to 42 h are connected to the input unit of the control device 41. A mode switch 25 (described later) is connected to the terminal 42a. The ground sensor 24 is connected to the terminal 42b, the tilt sensor 8 is connected to the terminal 42c, the interlock release switch 26 (described later) is connected to the terminal 42d, and the angle setting switch 27 (described later) is connected to the terminal 42e. . The terminal 42f is connected to the D terminal of the connector 50, the terminal 42g is connected to the C terminal of the connector 50, and the terminal 42h is connected to the B terminal of the connector 50. The mode switch 25 is a switch for selecting one of a first mode and a second mode described later. The interlock release switch 26 is a switch for arbitrarily releasing an interlock function (described later). The angle setting switch 27 is a switch used for setting an angle (second setting angle θ2) of the receiving platform 3 that is arbitrarily set with respect to the vehicle. The mode switch 25, the interlock release switch 26, and the angle setting switch 27 can be provided, for example, in the operation device 30 and other operation devices or the unit box 9 (FIG. 1).

  By being connected as described above, signals output from the inclination sensor 8, the ground sensor 24, the mode switch 25, the interlock release switch 26, the angle setting switch 27, and the operation device 30 are input to the control device 41, respectively. It has come to be. When the wiring relationship is organized with the connector 50 as a main component, first, the terminal A of the connector 50 is a terminal 42j (described later) of the control panel 40, the terminal B is a terminal 42h, the terminal C is a terminal 42g, the terminal D is a terminal 42f, Each is connected.

  Terminals 42i and 42j are power supply terminals. The terminal 42 i is an input terminal for a power source, and is connected to a power source BT (for example, a vehicle battery) via a power switch 28. The terminal 42j is an output terminal of the power supply, and is connected to the A terminal of the connector 50 during normal operation, the A terminal of the connector 60 during emergency operation, the D terminal of the connector 70, and the G terminal of the relay switch CB. . The relay switch CB is a vehicle-mounted relay mounted on a vehicle, for example, and includes five terminals (E terminal, F terminal, G terminal, H terminal, and I terminal). The E terminal and the F terminal are connected via a relay inside the relay switch CB. The G terminal is selectively connected to the terminals H and I through the switch inside the relay switch CB. Normally, the terminal G is connected to the terminal H via a switch (in a demagnetized state), but when the relay is excited, the switch is switched and the terminal G is connected to the terminal I. The E terminal of the relay switch CB is connected to the ground, and the B terminal of the emergency operation connector 70 and the terminal 42p of the control panel 40 are connected to the F terminal. As described above, the terminal 42j for power supply output of the control panel 40 is connected to the G terminal, and the I terminal is connected to the solenoid S6 of the switching valve V6 (FIG. 10). The H terminal is an empty terminal.

  Terminals 42k to 42o of the control panel 40 are input terminals to which connectors 60 and 70 for emergency operation are connected. The C terminal of the connector 60 is connected to the terminal 42k. The terminal 42l is connected to the B terminal of the connector 60, the terminal 42m is connected to the C terminal of the connector 70, the terminal 42n is connected to the B terminal of the connector 70, and the terminal 42o is connected to the C terminals of the connectors 60 and 70. Yes. When the connection relationship is organized with the connectors 60 and 70 as main components, the A terminal of the connector 60 is first connected to the terminal 42j of the control panel 40, the B terminal is connected to the terminal 42l, and the C terminal is connected to the terminals 42k and 42o. The B terminal of the connector 70 is connected to the terminal 42n of the control panel 40 and the terminal F of the relay switch CB, the C terminal is connected to the terminals 42m and 42o of the control panel 40, and the D terminal is connected to the terminal 42j. The D terminal of the connector 60 and the A terminal of the connector 70 are empty terminals.

  Terminals 42p-42v of the control panel 40 are output terminals of the control panel 40. The terminal 42p is connected to the F terminal of the relay switch CB as described above, and is connected to the output portion of the control device 41 inside the control panel 40. The terminal 42q is connected to the contactor relay CT, and is connected to the terminal 42o and the output unit of the control device 41 inside the control panel 40. The terminal 42r is connected to the solenoid S1 of the switching valve V1 (FIG. 10), and is connected to the terminals 42k and 42l and the output portion of the control device 41 inside the control panel 40. The terminal 42s is connected to the solenoid S2 of the switching valve V2 (FIG. 10), and is connected to the terminal 42l and the output portion of the control device 41 inside the control panel 40. The terminal 42t is connected to the solenoid S3 of the switching valve V3 (FIG. 10), and is connected to the terminal 42m and the output portion of the control device 41 inside the control panel 40. The terminal 42u is connected to the solenoid S4 of the switching valve V4 (FIG. 10), and is connected to the terminal 42n and the output portion of the control device 41 inside the control panel 40. The terminal 42v is connected to the solenoid S5 of the switching valve V5 (FIG. 10), and is connected to the output portion of the control device 41 inside the control panel 40.

(Control device)
The control device 41 has a load receiving table driving function, a mode setting function, an interlock function, and an interlock release function.

  The “load receiving table driving function” is a signal generated based on an operation signal from the operating device 30 is output to the drive system of the lift cylinder 4 or the tilt cylinder 5 to drive the load receiving table 3 up and down or tilted. It is a function to do. This is a basic function that is executed when unloading and storing the cargo receiving platform 3 and when handling cargo. Specifically, the procedure of FIG. 12 corresponds to the procedure of the cargo receiving table driving function.

  The “mode setting function” is a function that determines which one of the first mode and the second mode is selected and sets the reference angle θr of the receiving platform 3 used for the interlock function according to the selected mode. . In the case of this embodiment, specifically, the procedure of S112a-S112c in FIG. 13 described later corresponds to the procedure of the mode setting function.

  In the “first mode”, the reference angle θr is set with reference to the direction of gravity, and specifically, the first setting angle θ1 is set to the reference angle θr. The first set angle θ1 is an angle (for example, horizontal) of the receiving platform 3 when the output value of the tilt sensor 8 is a specific value (default preset value) set in advance (for example, at the manufacturing stage). In the present embodiment, as described above, the attachment angle of the inclination sensor 8 with respect to the load receiving platform 3 can be adjusted by the attachment member 10, so the reference angle θr can be adjusted by the attachment angle of the inclination sensor 8. In the present embodiment, when the attachment angle of the inclination sensor 8 with respect to the load receiving platform 3 is the standard angle β (FIG. 5), the reference angle θr of the load receiving platform 3 is 0 ° (horizontal).

  In the “second mode”, the reference angle θr is set with respect to the vehicle, and specifically, the second setting angle θ2 is set to the reference angle θr. The second set angle θ2 is, for example, a desired angle of the load receiving platform 3 that is arbitrarily visually adjusted separately from the first set angle θ1 by driving the tilt cylinder 5, and can be adjusted to the first set angle θ1. In principle, the angle is different from the first set angle θ1. For example, the load receiving platform 3 in the retracted state is horizontally deployed at the height of the floor surface of the loading platform A, the angle of the load receiving platform 3 is adjusted by visual observation, and the angle setting switch 27 is operated. The output value is stored in a memory (not shown) of the control device 41 as a value corresponding to the second set angle θ2.

  The “interlock function” is a function for executing a lift cylinder drive command on the condition that the angle θ of the load receiving platform 3 is the reference angle θr. In other words, when the angle θ of the load receiving platform 3 does not coincide with the reference angle θr, the function of disabling signal output to the drive system of the lift cylinder is maintained, and the angle θ of the load receiving platform 3 is maintained at the reference angle θr. It is a function to raise and lower. In the present embodiment, specifically, the procedure of S112d-S112f and S112h in FIG. 13 corresponds to the procedure of the interlock function.

  The “interlock release function” is a function that releases the interlock function when a condition is satisfied, and outputs a drive command to the drive system of the lift cylinder 4 according to the operation regardless of the angle θ of the load receiving platform 3. One of the conditions for releasing the interlock function is that it is determined that the receiving platform 3 is grounded based on the signal from the ground sensor 24. Further, in the present embodiment, another release condition is that the interlock release switch 26 is operated to release the interlock function. Specifically, the procedure of S112d-S112g in FIG. 13 corresponds to the procedure of the interlock release function.

-Operation-
(basic action)
The basic operation of the load receiving table lifting device described below corresponds to the load receiving table driving function of the control device 41. The control device 41 generates a command signal based on signals from the operation device 30, the tilt sensor 8, and the ground sensor 24 according to a program stored in a memory (not shown), and outputs the command signal to the solenoids S1-S6 and the contactor relay CT. Then, the lift cylinder 4 and the tilt cylinder 5 are driven. Although the case where the operating device 30 is operated will be described as an example, it is assumed here that the connector 35 of the operating device 30 is connected to the connector 50 for normal operation. As described above, the upper switch 31 is operated alone when the load receiving platform 3 is raised, and the lower switch 32 is operated independently when the load receiving platform 3 is lowered. When the load receiving platform 3 is tilted forward, the opening / closing switch 33 is operated simultaneously with the upper switch 31, and when the load receiving platform 3 is tilted backward, the opening / closing switch 33 is operated simultaneously with the lower switch 32. Based on this, the basic operation will be described in detail below.

  FIG. 12 is a flowchart showing a command output procedure by the control device to the loading platform driving device. The control device 41 repeatedly executes the procedure shown in the figure at a predetermined cycle time (for example, 0.01 s).

・ Closed operation (S101-S106)
When the power switch 28 is turned on and the power is turned on, the control device 41 starts the procedure shown in FIG. 12. First, the signal Sa of the tilt sensor 8, the signal Sg of the ground sensor 24, the signal Sm of the mode switch 25, and the interlock release switch. 26 signal Sr is input (S101). Thereafter, the control device 41 determines whether a signal from the open / close switch 33 is input (S102), and if it is input, determines whether a signal is input from the upper switch 31 (S103). If the opening / closing switch 33 and the upper switch 31 are simultaneously operated, the control device 41 determines whether the angle θ of the receiving platform 3 is different from the reference angle θr (S104). The flag F = 1 is set and the procedure of FIG. 12 is finished (S105). The flag F is a value for identifying whether or not the operating device 30 is being operated, and is set to F = 0 when there is no operation and F = 1 when the operation is performed. The initial value (when power is turned on) is F = 0.

  When a closing operation command is issued by the control device 41, the contactor relay CT and the solenoid S3 are excited while the solenoids S1, S2, S4-S6 remain in a demagnetized state. Thus, with the switching valves V1, V2, and V4-V6 closed, the motor 23 is connected to the power source BT and driven at the same time as the switching valve V3 is opened. As a result, the tilt cylinder 5 is extended by the hydraulic oil supplied from the hydraulic pump 22, and the load receiving platform 3 is tilted forward (rotated counterclockwise as viewed from the left side). When the loading platform 3 is at the height of the floor of the loading platform A, the above closing operation is performed, whereby the loading platform 3 can be stood along the rear surface of the loading platform A and stored.

  Further, when the simultaneous operation of the open / close switch 33 and the upper switch 31 is continuously performed and θ = θr is obtained while the procedure of S101 to S105 is repeated, the control device 41 determines whether F = 1. (S106). If F = 1, the control device 41 stops the closing operation command and ends the procedure of FIG. For example, when the closing operation is started from the posture in which the load receiving table 3 is tilted backward from the reference angle θr, the forward tilting operation of the load receiving table 3 is temporarily stopped when θ = θr. While the simultaneous operation of the opening / closing switch 33 and the upper switch 31 is continuously performed, the receiving platform 3 does not operate thereafter. When the simultaneous operation is interrupted (at least one of the open / close switch 33 and the upper switch 31 is turned off), F = 0 is set (S111, S114, S117-S119). Thereafter, when the simultaneous operation of the opening / closing switch 33 and the upper switch 31 is resumed, the control device 41 moves the procedure from S106 to S105 and issues a closing operation command even if θ = θr.

Opening operation (S101-S103, S107-S111)
When the signals Sa, Sg, Sm, Sr and the open / close switch 33 are input and the upper switch 31 is not input, the control device 41 determines whether the signal from the lower switch 32 is input (S107). ). When there is no signal input from the lower switch 32, the control device 41 sets F = 0 and finishes the procedure of FIG. 12 (S111), and when there is an input, moves the procedure to S108. The procedure from S108 to S110 corresponds to the procedure from S104 to S106. If the opening / closing switch 33 and the lower switch 32 are simultaneously operated, the control device 41 determines whether the angle θ of the receiving platform 3 is different from the reference angle θr (S108). The flag F = 1 is set and the procedure of FIG. 12 is finished (S109).

  When an opening operation command is issued by the control device 41, the solenoids S1-S3, S5 and the contactor relay CT are deenergized, and the solenoids S4, S6 are excited. Thereby, the switching valves V4, V6 are opened in a state where the switching valves V1-V3, V5 are closed and the motor 23 is stopped. As a result, the weight of the load receiving platform 3 acts in the contraction direction of the tilt cylinder 5, and the hydraulic oil is released from the tilt cylinder 5 to the hydraulic oil tank 21 through the tank oil passage LT2. As the tilt cylinder 5 contracts in this way, the load receiving platform 3 tilts backward (turns clockwise as viewed from the left side) under its own weight.

  When the simultaneous operation of the open / close switch 33 and the lower switch 32 is continuously performed and θ = θr is obtained while the steps S101-S103 and S107-S109 are repeated, the control device 41 is F = 1. Is determined (S110). If F = 1, the control device 41 stops the opening operation command. For example, when the opening operation is started from the posture in which the load receiving table 3 is tilted forward from the reference angle θr, the backward tilting operation of the load receiving table 3 is temporarily stopped when θ = θr. While the simultaneous operation of the opening / closing switch 33 and the lower switch 32 is continuously performed, the receiving platform 3 does not operate thereafter. When the simultaneous operation is interrupted (at least one of the open / close switch 33 and the lower switch 32 is turned off), F = 0 is set (S111, S114, S117-S119). When the simultaneous operation of the opening / closing switch 33 and the lower switch 32 is resumed, the control device 41 shifts the procedure from S110 to S109 and issues an opening operation command even if θ = θr.

-Ascent operation (S101, S102, S112-S114)
When the signals Sa, Sg, Sm, and Sr are input and no signal is input to the open / close switch 33, the control device 41 determines whether or not the interlock function is released (S112). The procedure of S112 will be described later. The control device 41 finishes the procedure of FIG. 12 when the interlock function is not released, and determines whether the signal from the upper switch 31 is input when it is released (S113). If the upper switch 31 has been operated, the control device 41 issues an ascending operation command and simultaneously sets the flag F = 1 and ends the procedure of FIG. 12 (S114).

  When the raising operation command is issued by the control device 41, the contactor relay CT and the solenoid S1 are excited while the solenoids S2-S6 remain in a demagnetized state. As a result, with the switching valve V2-V6 closed, the motor 23 is connected to the power source BT and driven simultaneously with the opening of the switching valve V1. As a result, the lift cylinder 4 is extended by the hydraulic oil supplied from the hydraulic pump 22 and the load receiving platform 3 is raised.

・ Descent operation (S101, S102, S112, S115-S119)
When the signals Sa, Sg, Sm, and Sr are input, the open / close switch 33 and the upper switch 31 are not input, and the interlock function is released, the control device 41 receives the signal from the lower switch 32. Is determined (S115). When there is no signal input from the lower switch 32, the control device 41 sets F = 0 and ends the procedure of FIG. 12 (S119). If the lower switch 32 is operated, the control device 41 determines whether or not the load receiving platform 3 is grounded (S116). If not, the controller 41 issues a first lowering operation command and simultaneously sets the flag F = 1. Then, the procedure shown in FIG. 12 is completed (S117). If the cargo receiving platform 3 is grounded at the time of the determination in S116, the control device 41 issues a second lowering operation command, and simultaneously sets the flag F = 1 and ends the procedure of FIG. 12 (S118).

  When a first lowering operation command is issued by the control device 41, the solenoids S1 and S2 are excited while the solenoids S3-S6 and the contactor relay CT remain in a demagnetized state. Thereby, the switching valves V1 and V2 are opened in a state where the switching valves V3-V6 are closed and the motor 23 is stopped. As a result, the weights of the load receiving platform 3, the lift arm 2, the lift cylinder 4 and the tilt cylinder 5 act in the contraction direction of the lift cylinder 4, and the hydraulic oil is transferred from the lift cylinder 4 to the hydraulic oil tank 21 via the tank oil passage LT1. Exit. As the lift cylinder 4 contracts in this way, the load receiving platform 3 is lowered by its own weight.

  When the second lowering operation command is issued by the control device 41, the solenoids S1, S2, S5 are excited while the solenoids S3-S4, S6 and the contactor relay CT remain in a demagnetized state. As a result, the switching valve V5 is opened in addition to the switching valves V1 and V2 while the switching valves V3-V4 and V6 are closed and the motor 23 is stopped. As a result, the weight of the load receiving platform 3 acts in the contraction direction of the lift cylinder 4, and in addition to the route via the tank oil passage LT1, the hydraulic oil tank 21 from the lift cylinder 4 via the route via the tank oil passages LT3 and LT2. The hydraulic oil will come off. As the lift cylinder 4 contracts in this way, the grounded load receiving platform 3 tilts backward as described above.

  As described above, the ascending operation, the descending operation, the forward tilting operation, and the backward tilting operation of the load receiving platform 3 are selectively performed, and a plurality of operations (for example, ascending and tilting forward) are performed simultaneously. Never executed. In the non-operation state, the cargo receiving platform 3 is not driven. When the interlock is functioning, only the tilting operation of the load receiving platform 3 is executed, and the raising / lowering operation is prohibited. When the interlock function is released, the lifting / lowering operation and the tilting operation are possible. However, when the angle of the load receiving platform 3 becomes the reference angle θr during the tilting, the operation of the load receiving platform 3 is temporarily stopped, and the tilting operation can be resumed by releasing the switch from the switches of the operating device 30 once.

(Interlock function setting)
FIG. 13 is a flowchart showing an interlock setting procedure by the control device. The procedure shown in FIG. 13 is the details of the procedure of S112 in FIG. 12, and corresponds to the above-described mode setting function, interlock function, and interlock release function.

  In the procedure of S112, the control device 41 first determines whether or not the signal Sm of the mode switch 25 is the signal Sm1 for identifying the designation of the first mode (S112a). If Sm = Sm1, the control device 41 sets the mode to the first mode, and sets the first setting angle θ1 described above as the reference angle θr (S112b). If the signal Sm is the signal Sm2 for identifying the designation of the second mode, the control device 41 sets the mode setting to the second mode, and sets the second setting angle θ2 described above as the reference angle θr (S112c). θ1 and θ2 are stored in a memory (not shown), and in the procedure of S112b and S112c, the control device 41 calls θ1 or θ2 from the memory, and stores the setting of θr = θ1 or θr = θ2 in the memory.

  When the procedure of S112b or S112c is completed, the control device 41 determines whether or not the angle θ of the load receiving platform 3 calculated based on the signal from the tilt sensor 8 is the reference angle θr (S112d). If θ = θr, the control device 41 releases the interlock function and ends the procedure of S112 (S112g). If θ ≠ θr, the control device 41 determines whether the interlock function is intentionally released by the operator using the interlock release switch 26 (S112e). If released, the control device 41 releases the interlock function and ends the procedure of S112 (S112g). If the interlock function is not intentionally released, the control device 41 determines whether or not the cargo receiving platform 3 is grounded based on the signal from the ground sensor 24 (S112f). If the receiving platform 3 is grounded, the control device 41 releases the interlock function and ends the procedure of S112 (S112g). If the receiving platform 3 is not grounded, the control device 41 enables the interlock function and ends the procedure of S112 (S112g).

  When the interlock function is invalidated through the procedure of S112g, the control device 41 lifts according to the operation regardless of the mode setting, the angle θ of the load receiving table 3, and whether or not the load receiving table 3 is grounded. Command the cylinder 4 to operate.

  When the interlock function is validated through the procedure of S112h under the first mode, the control device 41 sets the lift cylinder 4 according to the operation on the condition that the angle θ of the load receiving platform 3 is the first set angle θ1. Is moved up and down while maintaining the angle θ of the receiving tray 3 at the first set angle θ1. The first set angle θ1 is an absolute angle with respect to the direction of gravity, and the angle θ of the load receiving platform 3 during the raising / lowering operation is set to the first set angle θ1 (for example, horizontal or It is kept at a slightly forward tilted angle etc.).

  When the interlock function is validated through the procedure of S112h under the second mode, the control device 41 sets the lift cylinder 4 according to the operation on the condition that the angle θ of the load receiving platform 3 is the second set angle θ2. Is moved up and down while keeping the angle θ of the receiving platform 3 at the second set angle θ2. The second setting angle θ2 is typically an angle having a relative relationship with the angle of the vehicle on an inclined ground or the like (basically excluding the first setting angle θ1), and the angle setting switch 27 precedes the cargo handling operation each time. Is an angle set by The second set angle θ2 is also an absolute angle based on the direction of gravity as long as it is the output of the tilt sensor 8, but since it includes the setting of the relative angle with respect to the vehicle, in the second mode, The cargo receiving platform 3 moves up and down at a preset angle.

(Emergency action)
If an electrical device such as the tilt sensor 8 has a problem, it may be considered that the operation control of the load receiving platform 3 through the control device 41 is hindered. In that case, the connector 35 of the operation device 30 is connected to the connector 60 or 70 for emergency operation from the connector 50 for normal operation, the control device 41 is bypassed, and the operation device 30 is directly connected to the drive system of the load receiving platform lifting device. .

  When the lifting / lowering operation of the cargo receiving platform 3 is performed, the operating device 30 is connected to the connector 60. When connected to the connector 60, the A terminal of the operating device 30 is always connected to the power source BT via the terminal 42j of the control panel 40, and the load receiving platform 3 can be moved up and down by operating the upper switch 31 or the lower switch 32. Become. The open / close switch 33 is connected to a vacant terminal (D terminal of the connector 60) and becomes invalid.

  Specifically, when the upper switch 31 is operated with the operation device 30 connected to the connector 60, the solenoid S1 and the contactor relay are bypassed by bypassing the control device 41 via the operation device 30 and the A terminal and C terminal of the connector 60. CT connects to power supply BT. Thus, as in the case of the execution of S114 in FIG. 12, the contactor relay CT and the solenoid S1 are energized while the solenoids S2-S6 are de-energized, the switching valve V2-V6 is closed, and the switching valve V1 is opened simultaneously with the motor. 23 is connected to the power source BT and driven. As a result, the lift cylinder 4 is extended by the hydraulic oil supplied from the hydraulic pump 22 and the load receiving platform 3 is raised.

  When the lower switch 32 is operated while the operating device 30 is connected to the connector 60, the solenoids S1 and S2 are connected to the power source BT, bypassing the control device 41 via the operating device 30 and the B terminal of the connector 60. As a result, similarly to the execution of S117 in FIG. 12, the solenoids S1 and S2 are excited while the solenoids S3-S6 and the contactor relay CT remain in the demagnetized state. As a result, the switching valves V1 and V2 are opened while the switching valve V3-V6 is closed and the motor 23 is stopped, and the load receiving platform 3 is lowered by its own weight.

  When the tilting operation of the load receiving platform 3 is performed, the operating device 30 is connected to the connector 70. When connected to the connector 70, the opening / closing switch 33 of the operating device 30 is connected to the power source BT via the terminal 42 j of the control panel 40, and the opening / closing switch 33 is operated simultaneously with the upper switch 31 or the lower switch 32, thereby Can be tilted.

  Specifically, when the upper switch 31 is operated together with the opening / closing switch 33 in a state where the operation device 30 is connected to the connector 70, the solenoid bypasses the control device 41 via the operation device 30 and the C terminal and D terminal of the connector 70. S3 and the contactor relay CT are connected to the power source BT. As a result, the contactor relay CT and the solenoid S3 are excited while the solenoids S1, S2, S4-S6 remain in a demagnetized state as in the case of the execution of S105 in FIG. As a result, the tilt cylinder 5 extends, and the load receiving platform 3 tilts forward (turns counterclockwise as viewed from the left side).

  When the lower switch 32 is operated while the operating device 30 is connected to the connector 70, the solenoid S4 is connected to the power source BT, bypassing the control device 41 via the operating device 30 and the B terminal and D terminal of the connector 70. At the same time, the F terminal of the relay switch CB is connected to the power source BT via the B terminal and the D terminal of the operating device 30 and the connector 70, and the relay switch is switched to bypass the control device 41 and the solenoid S6 is connected to the power source BT. . As a result, similarly to the execution of S109 in FIG. 12, the solenoids S4 to S6 are excited while the solenoids S1-S3 and S5 and the contactor relay CT remain in the demagnetized state. As a result, the load receiving platform 3 tilts backward (turns clockwise as viewed from the left side) by its own weight.

-Effect-
(1) Unlike the proximity switch or the like used as a pair with the sensing plate, the tilt sensor 8 can measure its own angle with respect to the direction of gravity, and there is almost no error in measured values during forward tilting and backward tilting operations. Absent. According to the present embodiment, by providing the inclination sensor 8 in the load receiving platform 3, at least the front and rear angular postures of the load receiving platform 3 (absolute with respect to the direction of gravity as a reference) regardless of the posture of the vehicle (the angle of the ground contact surface). Can always be measured with high accuracy. Thus, for example, even when the vehicle is tilted back and forth on an inclined ground, the angle of the load receiving platform 3 during the cargo handling operation can be accurately controlled to the reference angle θr regardless of the tilt of the vehicle.

  In addition, the mounting member 10 for attaching the tilt sensor 8 to the load receiving platform 3 is provided with a guide hole 12 that is an arc-shaped long hole, so that the angle of the tilt sensor 8 is tilted around the pin 11. Can be adjusted in the direction. When the angle θ of the load receiving table 3 is determined based on the signal from the tilt sensor 8 during the lifting operation by the lift cylinder 4, the load receiving table 3 with respect to the output of the tilt sensor 8 is adjusted by adjusting the mounting angle of the tilt sensor 8 with respect to the load receiving table 3. Can be flexibly adjusted mechanically. For example, when the tilt sensor 8 is tilted backward from the standard angle β by an angle Δα with the pin 11 as a fulcrum when viewed from the left side of the load receiving platform 3, the reference angle θr of the load receiving platform 3 is tilted forward by the angle Δα. Since the reference angle θr desired at the time of cargo handling operation varies depending on the operator, such an adjustment mechanism is significant from the viewpoint of user friendliness. Further, since the tilt sensor 8 does not have a special element used as a set like the sensing plate of the proximity switch, the tilt sensor 8 has a high degree of freedom in layout.

  In the present embodiment, the case where the guide hole 12 is provided in the load receiving table 3 has been described as an example. However, since the bracket 14 and the load receiving table 3 only need to be relatively displaced, the guide hole 12 is not the load receiving table 3. It may be provided on the bracket 14. The same applies to the fulcrum hole 15 as a long hole. In addition, the mounting member 10 for attaching the tilt sensor 8 to the load receiving platform 3 includes the bracket 14. However, depending on the specifications of the tilt sensor 8 (such as the direction of the tilt to be measured), the bracket 14 may be omitted and the load receiving platform 3 may be omitted. It is good also as a structure which attaches the inclination sensor 8. FIG. Also in this case, if the inclination sensor 8 is attached to the load receiving tray 3 via the pin 11, the guide hole 12, and the fixture 13, the attachment angle of the inclination sensor 8 can be adjusted in the same manner as described above.

  (2) The inclination sensor 8 was accommodated in the stiffener 3A. By covering and protecting with the stiffener 3A, failure of the tilt sensor 8 can be suppressed. Moreover, since the inclination sensor 8 is covered with the stiffener 3A, the aesthetics of the load receiving table lifting device is also excellent. However, the arrangement of the inclination sensor 8 is not limited to the inside of the stiffener 3A as long as the essential effect (1) is obtained. Can be changed.

  (3) Since the mounting angle of the inclination sensor 8 with respect to the load receiving platform 3 is set to the standard angle β by providing the recess 12A of the guide hole 12 and aligning the fixture 13 with the recess 12A, the load receiving platform 3 The reference angle θr can be reset to easily return to the standard value. In the present embodiment, as an example, when the mounting angle of the inclination sensor 8 is the standard angle β, the load receiving platform 3 is configured to be horizontal (θr = 0), and therefore the horizontal of the load receiving platform 3 is easily set. be able to. Further, since the fulcrum hole 15 through which the pin 11 passes is a long hole extending in the recess direction of the recess 12A, when the fixture 13 is aligned with the recess 12A, the tilt sensor 8 is shifted in the recess direction so It can be fixed with. However, as long as the effect (1) is obtained, such a configuration that resets the mounting angle of the tilt sensor 8 to the standard angle β is not necessarily required and may be omitted. In this case, the fulcrum hole 15 can be a circular hole, which facilitates processing. Further, since the pin 11 only rotates and does not shift, it is not necessary to tighten or loosen the pin 11. Therefore, it is not necessary to use a bolt for the pin 11, and it can be changed to a configuration in which a pin without a screw is used as the pin 11 and appropriately prevented. Furthermore, as long as a configuration for resetting to the standard angle β is provided, an aim indicating the standard angle β may be simply displayed in the guide hole 12.

  (4) Further, since the interlock function for executing the drive command for the lift cylinder 4 is provided on condition that the angle θ of the load receiving table 3 is the reference angle θr, for example, an erroneous operation is performed when the load receiving table 3 is largely inclined. As a result, it is possible to avoid the cargo receiving table 3 from going up and down against the operator's intention. In addition, in the present embodiment, the interlock functions based on the signal from the tilt sensor 8, and as described in the description of the first mode, the absolute direction based on the direction of gravity is used regardless of the tilt of the vehicle (ground plane). It is possible to keep the angle of the load receiving platform 3 at the time of the cargo handling operation at a proper angle. Furthermore, by switching to the second mode, it is possible to flexibly cope with the inclination of the ground on which the vehicle has stopped without adjusting the mounting angle of the inclination sensor 8 and to set the load receiving platform 3 arbitrarily set for the vehicle. The load receiving platform 3 can be raised and lowered while maintaining a relative angle. However, as long as the above effect (1) is obtained, such a switching function to the second mode is not necessarily required and may be omitted.

  (5) In the present embodiment, emergency operation connectors 60 and 70 are provided in the drive system of the drive device such as the lift cylinder 4, the tilt cylinder 5, and the motor 23, bypassing the control device 41 and directly connected. Alternatively, the controller device 30 can be reconnected to 70. Even if the control device 41 interferes with the execution of the load receiving table driving function due to a malfunction of an electrical device such as the tilt sensor 8, the operation device 30 can be connected to the connector 60 or 70 without using the control device 41. A signal can be directly input from 30 to the drive system of the drive device. As a result, even if the operation of the cargo cradle lifting device via the control device 41 becomes unstable, the cargo cradle lifting device is operated urgently, for example, the cargo cradle 3 can be shifted to the retracted position. In addition, when performing an emergency operation, the operator needs to change the operation device 30 with a clear intention. For example, the function of the control device 41 is contrary to the operator's intention during normal cargo handling work. It is possible to avoid such a situation that the cargo receiving platform lifting / lowering device performs an unexpected operation when is released. However, the emergency operation connectors 60 and 70 are not necessarily required as long as the effect (1) is obtained.

  (6) A connector 60 provided with two cylinders (lift cylinder 4 and tilt cylinder 5) for driving the load receiving table 3 and directly connected to the drive system of the lift cylinder 4 and a connector 70 directly connected to the drive system of the tilt cylinder 5 Prepared separately. The connector 35 of the operation device 30 is configured to be alternatively connectable to any of the connectors 50, 60, and 70, and the operator has a clear intention as to which drive device to operate in an emergency. The connectors 60 and 70 are selected, which can contribute to suppression of erroneous operations.

  In the present embodiment, the plurality of connectors 60 and 70 are provided for the emergency operation according to the operation target. However, as long as the effect (1) is obtained, a single emergency operation connector may be used. In that case, the connection relationship between the connector for emergency operation and the drive system of the drive device may be such that the same operation as that when the operation device 30 is connected to the connector 50 can be performed.

  (7) In the present embodiment, the lift cylinder 4 can be operated only by the upper switch 31 or the lower switch 32, while the tilt cylinder 5 cannot be operated unless the upper switch 31 or the lower switch 32 is operated simultaneously with the opening / closing switch 33. It is like that. That is, the tilt cylinder 5 does not operate unless the operating device 30 is operated with both hands. This is a consideration to ensure that the tilting operation of the load receiving platform 3 is accompanied by a particularly clear intention. As for the connection relationship between the connectors 60 and 70 and the drive system of the drive device, the tilt cylinder 5 cannot be operated unless the upper switch 31 or the lower switch 32 is operated simultaneously with the opening / closing switch 33. Since an operator may be frustrated during an emergency operation, such a configuration is effective in preventing unexpected operations. However, this configuration is not essential as long as the effect (1) is obtained.

  (8) As described above, when the switching valves V1 and V2 are opened, the lift arm 2 and the tilt cylinder 5 are rotated with respect to the tilt arm 7 before the load receiving base 3 is grounded, and the load receiving base 3 is self-weighted. To translate downward. After the load receiving table 3 is grounded, the tilt arm 7 is rotated with respect to the support frame 1 by the weight of the load receiving table 3, and the load receiving table 3 is tilted backward with the pin P4 as a fulcrum. This is a mechanism that automatically switches to a backward tilting operation after grounding during the operation of lowering the load receiving platform 3. The descending operation of the load receiving platform 3 is performed by opening the switching valves V1 and V2 so that the lift cylinder 4 and the hydraulic oil tank 21 are connected by the tank oil passage LT1, and the hydraulic oil is transferred from the oil chamber to the hydraulic oil tank 21 by the weight of the load receiving platform 3. By being discharged and the lift cylinder 4 contracts.

  In the present embodiment, in the load receiving platform lifting device in which the load receiving platform 3 tilts mechanically by the lowering operation after the ground contact, the tank that bypasses the tank oil passage LT1 and connects the oil chamber of the lift cylinder 4 to the hydraulic oil tank 21. An oil passage LT2 is added, and this is configured to be opened and closed by a switching valve V5. While the lower switch 32 of the operating device 30 is operated and a signal for lowering the load receiving table 3 is input, the control device 41 switches the switching valves V1, V2 when the grounding sensor 24 does not detect the grounding of the load receiving table 3. , V5, only the switching valves V1, V2 relating to the tank oil passage LT1 are opened. On the other hand, when the grounding sensor 24 detects the grounding of the cargo receiving platform 3, the control device 41 relates to the switching valves V1, V2 related to the tank oil passage LT1 and the tank oil passage LT2 according to the same operation signal as that during the lowering operation. Open both switching valves V5. The force applied to the oil chamber of the lift cylinder 4 decreases after contact with the ground of the load receiving table 3 and the operation (backward tilt) speed of the load receiving table 3 may be insufficient depending on the operating oil temperature or the like. The oil passage LT2 is opened and the cross-sectional area of the hydraulic oil discharge passage is increased. As a result, the hydraulic oil discharge flow rate can be increased to compensate for the lack of the backward tilting speed of the load receiving platform 3 by the lift cylinder 4. On the other hand, the tank oil passage LT2 is shut off by the switching valve V5 and the lift cylinder 4 is connected to the hydraulic oil tank 21 only in the tank oil passage LT1 before the contact with which a larger force is applied to the oil chamber than after the contact. Therefore, the descending speed will not be faster than necessary. In this way, the descending operation due to the weight of the load receiving platform 3 and the backward tilting operation after the grounding can be made appropriate and smooth. However, as long as the effect (1) is obtained, it is not always necessary to provide the tank oil passage LT2.

  (9) Since the pressure sensor is used for the ground sensor 24, a sensor for detecting the ground of the cargo receiving platform 3 can be incorporated in the hydraulic circuit. Here, for example, the grounding of the load receiving table 3 can also be detected by providing the load receiving table 3 with a switch or a distance meter for detecting contact with the ground. Further, a configuration in which the fixed stroke of the lift cylinder 4 and the fixed angle of the lift arm 2 are detected by a proximity sensor, a distance meter, an angle meter, a rotation sensor, or the like to determine the grounding of the load receiving table 3 is also conceivable. However, the configuration in which sensors are installed on these movable elements complicates the structure of the apparatus, and there is a concern that defects may easily occur in the sensors due to interference with the ground and other obstacles. These disadvantages can be eliminated by using a pressure sensor for the ground sensor 24. However, as long as the effect (1) is obtained, the ground sensor 24 may be replaced with another type of sensor.

  (10) Since the tilt arm 5 serves as a link arm that constitutes a parallel link together with the lift arm 2, a mechanism that achieves both a lifting operation (parallel movement) and a tilting operation of the load receiving platform 3 can be simply configured. However, as long as the above effect (1) is obtained, for example, a tilt mechanism that tilts the load receiving platform 3 is configured separately from the parallel link, and the parallel link is driven by the lift cylinder 4, while separately from the parallel link. The tilt mechanism may be driven by the provided tilt cylinder.

  (11) Since the control device 41 has an interlock function for executing a drive command for the lift cylinder 4 on the condition that the load receiving platform 3 is at the reference angle θr, the interlock functions uniformly under this condition. In this case, the backward tilting operation after the grounding of the cargo receiving table 3 described above becomes impossible. This is because the command to the drive system of the lift cylinder 4 is interrupted by the inclination of the load receiving platform 3. It is possible to drive the tilt cylinder 5 to tilt the load receiving table 3 in the grounded state, but unless the interlock is released intentionally, the load receiving table 3 must be accurately returned to the reference angle θr by the tilt cylinder 5. The base 3 cannot be raised thereafter. In any case, the merit that a normal cargo handling operation can be performed simply by operating only the upper switch 31 and the lower switch 32 is lost.

  On the other hand, in the present embodiment, the control device 41 is provided with an interlock release function for releasing the interlock function on condition that the grounding sensor 24 detects the grounding of the load receiving table 3. Thereby, the merit of the ease of operation at the time of cargo handling work is not impaired. Combined with the optimization of the backward tilting speed of the load receiving table 3 at the time of ground contact by opening the tank oil passage LT2, it contributes to the efficiency of the cargo handling work. However, even if the interlock release function in cooperation with the ground sensor 24 is omitted, the effect (1) can be obtained.

DESCRIPTION OF SYMBOLS 2 ... Lift arm, 3 ... Load receiving stand, 3A ... Stiffener, 4 ... Lift cylinder, 5 ... Tilt cylinder, 8 ... Tilt sensor, 10 ... Mounting member, 11 ... Pin, 12 ... Guide hole, 12A ... Depression, 13 ... Fixed 25 ... mode switch, 27 ... angle setting switch, 41 ... control device, P2 ... pin (rotating shaft of the load receiving table), 15 ... fulcrum hole, O ... rotation center of the tilt sensor, β ... standard angle, θ ... An angle of the receiving platform,? 1 ... first setting angle,? 2 ... second setting angle,? R ... reference angle

Claims (6)

A lift arm pivotable up and down with respect to the vehicle;
A cradle connected to the tip of the lift arm so as to be pivotable up and down;
A lift cylinder for rotating the lift arm up and down;
A tilt cylinder that rotates the load receiving table up and down with respect to the lift arm;
An inclination sensor for measuring the inclination of the receiving platform with respect to the direction of gravity;
A load receiving and lowering device including an attachment member for attaching the inclination sensor to the load receiving stand,
The attachment member is
A pin that extends in a direction in which the rotation axis of the load receiving table extends and serves as a rotation center of the tilt sensor with respect to the load receiving table;
A guide hole which is an arc-shaped long hole centered on the rotation center;
A load receiving table elevating device comprising: a fixture that is inserted into the guide hole and fixes the inclination sensor to the load receiving table.   2. The load receiving platform lifting apparatus according to claim 1, wherein the tilt sensor is housed inside a stiffener of the load receiving platform. In the load receiving platform lifting apparatus according to claim 1 or 2,
A depression is formed in the outer peripheral part or inner peripheral part of the guide hole,
The fulcrum hole which is a pin hole through which the pin passes is a linear long hole extending from the center of the arc of the guide hole in the depression direction of the depression,
The load receiving table lifting / lowering device is configured such that a mounting angle of the tilt sensor with respect to the load receiving table becomes a standard angle by matching the fixing tool with the recess.   The load receiving platform lifting apparatus according to any one of claims 1 to 3, wherein the interlock is configured to execute a drive command for the lift cylinder on condition that an angle of the load receiving platform calculated from an output of the tilt sensor is a reference angle. A load receiving table lifting device including a control device having a function. The load receiving table lifting device according to claim 4,
An angle setting switch that arbitrarily sets a second setting angle of the cargo cradle with respect to the vehicle separately from the first setting angle of the cargo cradle stored in the control device;
A mode switch for selecting either the first mode or the second mode;
The control device sets the first set angle as the reference angle when the first mode is selected by the mode switch, and sets the second set angle as the reference when the second mode is selected. Lifting device for lifting the cradle at an angle.   6. The load receiving platform lifting apparatus according to claim 4, wherein the reference angle is adjustable by the attachment member.

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