JP2018162016A - Retractable cargo receiving base lifting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a retractable cargo receiving base lifting device capable of restraining reduction in smoothness of storage operation of a cargo receiving base resulting from occurrence of an unnecessary re-lifting operation.SOLUTION: A retractable cargo receiving base lifting device 4 comprises a cargo receiving base 5, a slider 9 which moves along a guide rail 8 provided in a lower part of a vehicle, a slide cylinder 14 for moving the slider 9, arms 17-19 liftably connecting the cargo receiving base 5 relative to the slider 9, and a lift cylinder 20 for lifting and lowering the cargo receiving base 5. The retractable cargo receiving base lifting device 4 comprises a gate sensor 56 for detecting a vertical position of the cargo receiving base and a control device 45 for controlling the lift cylinder 20 and the slide cylinder 14. When storing the cargo receiving base 5, the control device 45 lifts the cargo receiving base 5 to an intermediate area in a set height range by continuously driving the lift cylinder 20 for set time T0 from a time when it is detected that the cargo receiving base 5 has reached a lower limit of the set height range based on a signal from the gate sensor 56, after which pulls in the cargo receiving base 5 by driving the slide cylinder 14.SELECTED DRAWING: Figure 15

Description

  The present invention relates to a retractable cradle lifting and lowering device that supports loading and unloading work such as luggage on a loading platform of a vehicle.

  The load receiving platform lifting / lowering 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 loading and unloading work such as luggage on the loading platform of the vehicle. Among the load receiving table lifting devices, there is a retractable type that retracts to the lower side of the vehicle frame and stores the load receiving table. In this kind of load receiving device lifting device, when the sensor detects that the load receiving plate is first lifted and reaches a predetermined height in the storing operation, the operation is switched to the forward operation and the load receiving table is pulled to the lower side of the vehicle (Patent Document). 1 etc.).

Japanese Patent No. 3318271

  However, the sensor that detects that the cargo cradle is at a predetermined height has a narrow detection range, and if the cradle oscillates up and down while pulling the cargo cradle to the retracted position, it switches unintentionally from the on state to the cut state. There is a possibility that. In particular, the higher the responsiveness of the sensor, the quicker the operation proceeds when the sensor is switched from the cut-off state to the on-state. However, when the on / off state of the sensor is discriminated by comparing the sensor output with the threshold value, the sensor is turned off only by moving the load receiving table slightly downward during forward movement due to vibration or the like. When the sensor is turned off, the control unit misrecognizes that the loading platform has not reached the predetermined height and tries to raise the loading platform again. May be reduced.

  An object of the present invention is to provide a retractable load receiving device lifting / lowering device capable of suppressing a decrease in smoothness of a load receiving device storing operation caused by an unnecessary re-lifting operation.

  In order to achieve the above object, the present invention provides a load receiving table, a guide rail provided at a lower portion of a vehicle, a slider that moves along the guide rail, a slide cylinder that moves the slider, and the load receiving table with respect to the slider. In a retractable load receiving device lifting apparatus including an arm that connects the load receiving device and a lift cylinder that lifts and lowers the load receiving device, a sensor that detects a vertical position of the load receiving device, and the lift cylinder and the slide cylinder are controlled. When storing the consignment pedestal, the control device is configured for a set time from a point in time when it is detected based on a signal of the sensor that the consignment cradle has reached a lower limit of a set height range. Drive the slide cylinder after continuously driving the lift cylinder to raise the load receiving platform to an intermediate region of the set height range Characterized in that draw the receiving platform Te.

  ADVANTAGE OF THE INVENTION According to this invention, the fall of the smoothness of the storing operation of the load receiving stand by generation | occurrence | production of an unnecessary re-lifting operation | movement can be suppressed.

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 device according to a first embodiment of the present invention. It is a perspective view showing the detailed structure of the retractable cradle lifting device according to the first embodiment of the present invention. It is a left view showing the detailed structure of the retractable load receiving table lifting apparatus according to the first embodiment of the present invention. It is arrow sectional drawing of the left end vicinity part by the IV-IV line | wire in FIG. 3 of the retractable load receiving stand raising / lowering apparatus which concerns on 1st Embodiment of this invention. It is arrow sectional drawing by the VV line | wire in FIG. 4 of the retractable receiving stand raising / lowering apparatus which concerns on 1st Embodiment of this invention. It is a left view of the slider of the retractable load receiving table raising / lowering device according to the first embodiment of the present invention. FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 6. It is sectional drawing of the state which pulled out the load receiving stand of the load receiving stand raising / lowering apparatus of the retractable load receiving stand raising / lowering apparatus which concerns on 1st Embodiment of this invention. It is a top view of the fall prevention member with which the retractable load receiving device raising / lowering device according to the first embodiment of the present invention is provided. It is a rear view of the fall prevention member with which the retractable load receiving table raising / lowering device according to the first embodiment of the present invention is provided. It is a circuit diagram showing the example of 1 composition of the power unit with which the retractable load receiving device raising and lowering device concerning a 1st embodiment of the present invention was equipped. It is a functional block diagram showing the example of 1 composition of a control device with which the retractable cargo receiving stand raising / lowering device concerning a 1st embodiment of the present invention was equipped with peripheral equipment. It is the schematic which put together the attitude | position in the expansion | deployment operation | movement of the load receiving platform raising / lowering apparatus which concerns on 1st Embodiment of this invention, and the relationship between input-output signals in the table | surface form. It is the schematic which put together the attitude | position in the storage operation | movement of the load receiving platform raising / lowering apparatus which concerns on 1st Embodiment of this invention, and the relationship of an input-output signal in the table | surface form. It is a flowchart showing the control procedure of the load receiving table raising / lowering apparatus which concerns on 1st Embodiment of this invention. It is a flowchart showing the control procedure of the load receiving table raising / lowering apparatus which concerns on 2nd Embodiment of this invention.

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

(First embodiment)
1. 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. In the present specification, the left and right in FIG.

  The vehicle shown in FIG. 1 includes a vehicle frame 1, a cab 2 provided in front of the vehicle frame 1, a cargo bed 3 mounted on the vehicle frame 1, and a retractable load receiving platform lifting device ( Hereinafter, a cargo receiving platform lifting device 4 is provided. For example, during the traveling operation, the load receiving platform lifting device 4 folds the load receiving platform 5 and stores it in a storage position (described later) on the lower side of the vehicle frame 1. On the other hand, at the time of cargo handling work (loading and unloading work on the loading platform 3), the loading platform 5 is pulled out to the outside of the vehicle frame 1 (backward in the present embodiment) and deployed, and between the floor surface height of the loading platform 3 and the ground height. Raise and lower to support cargo handling work.

  2 is a perspective view showing the detailed structure of the load receiving platform lifting device, FIG. 3 is a left side view, FIG. 4 is a cross-sectional view taken along the line IV-IV in FIG. 3, and FIG. It is arrow sectional drawing by the VV line. 6 is a left side view of a slider (described later), FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 6, and FIG. 8 is a diagram of a state in which the load receiving platform of the load receiving platform lifting apparatus shown in FIG. It is. FIG. 3 shows a state in which the power unit 26 and the operation device 27 are removed.

  As shown in FIGS. 2 to 8, the load receiving platform lifting / lowering device 4 includes the load receiving platform (platform) 5 on which the load is loaded, the slide drive unit 6 that moves the load receiving stand 5 and the like in the front-rear direction, and the load receiving stand. And an elevating drive unit 7 that elevates and lowers 5. As will be described later, the loading platform 5 slides back and forth together with the elevating drive unit 7 during deployment and storage. In the specification of the present application, the front end of the slide range of the load receiving platform 5 and the lifting drive unit 7 is “front end position”, the rear end is “rear end position”, and the position between the front end position and the rear end position, that is, the horizontal setting position is “ It is defined as “intermediate position”. The front end position is a position during storage, and the rear end position is a position during cargo handling work. Further, as the vertical position of the load receiving platform 5, the height contacting the guide rail 8 (described later) is “storage height”, the height contacting the ground is “ground contact height”, and the height between the storage height and the contact height is The set height, that is, the set position in the vertical direction is defined as “intermediate height”. Furthermore, when the load receiving platform 5 is at the storage height at the front end position, it is described that the load receiving platform 5 is at the “storage position”, and when the load receiving platform 5 is at the ground contact height at the rear end position, It is described as being in the “contact position”.

1-1. Slide Drive Unit The slide drive unit 6 includes a pair of left and right guide rails 8, left and right sliders 9, a connecting member 10, left and right bracket portions 11, a support roller 12, a support frame 13 (see FIG. 3), and a slide cylinder 14. ing.

  Two guide rails 8 extend in the front-rear direction and are arranged in parallel in the left-right direction, and are attached to the lower rear portion of the vehicle frame 1 via an attachment portion 8a. The left and right guide rails 8 are connected to each other at a front end portion by a stay 8b extending left and right. Further, as shown in FIG. 7 and the like, the guide rail 8 has an I-shaped cross section in which a horizontal top plate portion 8l and a bottom plate portion 8m facing each other are connected by a vertical middle plate portion 8n.

  Each of the left and right sliders 9 includes two brackets 9a, an upper traveling roller 9b, a lower traveling roller 9c, and scrapers 9d and 9e. 5 and 8, the bracket 9a on the near side is not shown in order to illustrate the internal structure of the slider 9.

  The two brackets 9a are members constituting the main body of the slider 9, and are opposed to the left and right with the guide rail 8, the upper traveling roller 9b, and the lower traveling roller 9c interposed therebetween. A slight gap is interposed between the guide rail 8 and the two brackets 9a sandwiching it.

  The upper running roller 9b is provided so that the outer peripheral surface is brought into contact with the upper surface of the guide rail 8 and rolls on the upper surface of the guide rail 8 as the slider 9 moves. The lower traveling roller 9c is provided so that its outer peripheral surface is in contact with the lower surface of the guide rail 8 and rolls on the lower surface of the guide rail 8 as the slider 9 moves. That is, the slider 9 travels along the guide rail 8 by the upper traveling roller 9b and the lower traveling roller 9c sandwiching the guide rail 8 from above and below. The weight of the slider 9 and members supported by the slider 9 is supported by the guide rail 8 via the upper traveling roller 9b and the lower traveling roller 9c, except when the load receiving platform 5 or the like is at the front end position. At this time, since the slider 9 is located in front of the center of gravity of the load receiving platform elevating device 4, the upper traveling roller 9b is disposed behind the lower traveling roller 9c to support the moment. In this embodiment, the guide rail 8 is made of iron so as to have sufficient strength to receive the surface pressure from the upper traveling roller 9b and the lower traveling roller 9c.

  The shaft (pin) 9f of the upper traveling roller 9b and the lower traveling roller 9c has a double-supported beam structure in which both ends are supported by two brackets 9a sandwiching the guide rail 8, and the two brackets 9a are supported by the shaft 9f. Are connected. Further, a grease supply passage 9g (see FIG. 7) having a part opened in the outer peripheral portion is provided inside the shaft 9f, and a plug (not shown) is removed and grease is injected from the injection port 9h with a grease gun or the like. Thus, the upper traveling roller 9b and the lower traveling roller 9c can be lubricated.

  The scrapers 9d and 9e are provided between the two brackets 9a sandwiching the guide rail 8 so as to contact the surface of the guide rail 8. Specifically, the scraper 9 d is fixed to a bracket 9 i fixed to the bracket 9 a with a bolt and is in contact with the upper surface of the guide rail 8. The scraper 9e is fixed to a bracket 9j fixed to the bracket 9a with a bolt and is in contact with the lower surface of the guide rail 8. The scrapers 9d and 9e are positioned in a direction (rear side in this example) to pull out the load receiving platform 5 with respect to the upper traveling roller 9b and the lower traveling roller 9c, respectively, and precede the upper traveling roller 9b and the lower traveling roller 9c when moving backward. . The scrapers 9d and 9e are made of rubber or resin, for example.

  The connecting member 10 is a member that connects the left and right sliders 9, and both end portions penetrate the bracket 9 a and protrude outward from the slider 9 (outside in the body width direction). The bracket portion 11 is provided at the left end of the connecting member 10. The support frame 13 extends rearward from the connecting member 10 and is located near the center between the left and right sliders 9. The support roller 12 is in contact with the load receiving platform 5 during storage and unfolding, and is rotatably provided at the front end (rear end) of the support frame 13 in a posture in which the rotation shaft extends left and right. One end of the slide cylinder 14 is fixed to the stay 8 b via a bracket, and the other end is fixed to the support frame 13. As the slide cylinder 14 expands and contracts, the upper travel roller 9 b and the lower travel roller 9 c roll on the guide rail 8 and the left and right sliders 9 travel, and the elevating drive unit 7 moves back and forth integrally with the load receiving platform 5. .

  Further, steps 8c and 8d (see FIG. 6 and the like) are provided on the upper and lower surfaces of the guide rail 8, respectively. In the present embodiment, the portion on the front side of the step 8c on the upper surface of the guide rail 8 is relatively lower than the portion on the rear side of the step 8c. Similarly, the front part of the lower surface of the guide rail 8 relative to the step 8d is relatively higher than the rear part of the step 8d. These steps 8c and 8d are provided at positions where the upper traveling roller 9b and the lower traveling roller 9c must get over when the load receiving platform 5 is pulled out from the front end position. Specifically, the steps 8c and 8d are provided at positions that come to the rear side of the upper traveling roller 9b and the lower traveling roller 9c, respectively, when the slider 9 is at the front end position. Here, “the rear side of the upper traveling roller 9b and the lower traveling roller 9c” means the rear side of the portion of the upper traveling roller 9b and the lower traveling roller 9c that is closest to the guide rail 8 (contacts the guide rail during traveling), That is, the lower edge portion of the upper traveling roller 9b and the upper edge portion of the lower traveling roller 9c. The meaning of the rear side of the trailing edge of the traveling roller is not limited.

  Pressing rollers 8e (see FIG. 5 and the like) are provided at the lower portions of the left and right guide rails 8, respectively. The pressing roller 8e is rotatably supported on the lower surface of the guide roller 8 through a bracket 8f with a posture in which the shaft extends to the left and right. The pressing roller 8e is disposed at the rear portion of the guide rail 8 so as to come into contact with the load receiving platform 5 that rises during the storing operation. The bracket 9a of the slider 9 is provided with presser plates 9l and 9m (see FIG. 5 and the like) at upper and lower positions with the guide rail 8 interposed therebetween. Pads 8g and 8h are respectively provided on the upper surface of the guide rail 8 and the stay 8b at positions corresponding to the press plates 9l and 9m when the load receiving platform 5 is in the retracted position. The pads 8g and 8h receive the weight of the slider 9 and elements attached thereto in the storage position. When the load receiving platform 5 is retracted to the retracted position (the slider 9 is retracted to the front end position) and the upper traveling roller 9b and the lower traveling roller 9c exceed the steps 8c and 8d, the holding plates 9l and 9m come into contact with the pads 8g and 8h. To do. In this way, at the front end position, the slider 9 is restrained from above and below without play by pressing the pads 8g and 8h from above and below with the holding plates 9l and 9m. At this time, as described above, the distance between the upper surface and the lower surface of the guide rail 8 is shorter in the front part than the steps 8c and 8d than in the rear part. Therefore, when the slider 9 is at the front end position and supported by the pads 8g and 8h, the upper traveling roller 9b and the lower traveling roller 9c are separated from the upper and lower surfaces of the guide rail 8. A roller cover 9k (FIG. 2 and the like) that covers the upper side of the upper running roller 9b is fixed to the bracket 9i and the pressing plate 9l of the scraper 9d with bolts or the like (FIGS. 4 and 6 remove the roller cover 9k). Is shown).

  The guide rail 8 is provided with a rear end sensor 15 and an intermediate sensor 16 (see FIG. 12). For example, the rear end sensor 15 is provided at the rear portion of the guide rail 8 so as to be positioned between the top plate portion 8l and the bottom plate portion 8m. The slider 9 is provided with a striker 9n (see FIG. 8 and the like) on the inner wall surface of the bracket 9a. When the slider 9 moves backward and the striker 9n hits the stopper 8i provided near the rear end of the guide rail 8, the striker 9n is detected by the rear end sensor 15 to detect that the slider 9 is at the rear end position. The intermediate sensor 16 is a sensor that detects that the slider 9 is in the intermediate position. For example, by providing a striker (not shown) on the slider 9 and providing the intermediate sensor 16 on the guide rail 8 so as to be close to the striker when the slider 9 is at the intermediate position, the slider 9 at the intermediate position can be detected. For example, a proximity sensor or a limit switch can be used for the rear end sensor 15 and the intermediate sensor 16.

1-2. Lift Drive Unit The lift drive unit 7 includes a first arm (tilt arm) 17, a second arm (lift arm) 18, a third arm (compression arm) 19, and a lift cylinder 20. As for the 1st arm 17, the upper end part is connected with the bracket 10a (refer FIG. 4) provided in the connection member 10 so that rotation is possible. As for the 2nd arm 18, the base end part (front end part) is connected with the 1st arm 17, and the front-end | tip part (rear end part) is connected with the load receiving stand 5, respectively so that rotation is possible. The third arm 19 is connected to the bracket 10a so that a base end portion (front end portion) and a front end portion (rear end portion) to the load receiving platform 5 are rotatable. The lift cylinder 20 is rotatably connected to the lower end of the first arm 17 on the rod side and to the second arm 18 on the bottom side. The second arm 18 and the third arm 19 form a parallel link that connects the load receiving platform 5 to the slider 9 so as to be movable up and down, and the parallel link is driven to rotate up and down as the lift cylinder 20 extends and contracts. Thus, the load receiving platform 5 moves up and down while maintaining a horizontal posture.

1-3. Load receiving table The load receiving table 5 includes a load receiving table base 21 supported by the elevating drive unit 7 and a load receiving table main body 23 rotatably connected to the load receiving table base 21 via a hinge 22. Both ends of the hinge 22 are rotatably connected to the load receiving base 21 and the load receiving main body 23 via pins (not shown), respectively, and the rotation mechanism of the load receiving main body 23 with respect to the load receiving base 21 is It has a double joint structure through the hinge 22. The load receiving base body 23 is folded on the upper portion of the load receiving base 21 as shown in the drawings when stored. At the connecting portion (or hinge 22) between the second arm 18 and the load receiving base 21, the posture of the load receiving base 5 during the storing operation as a value for determining whether or not the load receiving base 5 is at an intermediate height. A gate sensor 56 (see FIG. 12) for detecting (folded state) is provided. As the gate sensor 56, an angle sensor that detects an angle of the load receiving base 21 (or the hinge 22) with respect to the second arm 18 (or the load receiving base 21) can be used. The gate sensor 56 does not detect a predetermined angle, but a range is given to the detection angle although it is slight. When the load receiving platform 5 is in the set height range including the intermediate height, it enters the state and detects that the load receiving platform 5 is in the set height range. Alternatively, the gate sensor 56 itself simply outputs an angle detection signal, and the control device 45 to be described later detects that the load receiving platform 5 is within the set height range based on the signal from the gate sensor 56. Also good.

1-4. Fall prevention member The guide rail 8 and the cargo cradle 5 are provided with a fall prevention member 75 (see FIG. 5 and the like) that restricts the downward movement of the cargo cradle 5 in the retracted position and suppresses the unexpected fall of the cargo cradle 5. It has been. The fall prevention member 75 includes a first member 76 (see FIG. 8) attached to the lower surface of the rear end portion of the guide rail 8 and a second member attached to the back surface (the surface facing upward during storage) of the cargo receiving table main body portion 23. 77 (see FIG. 8). A plan view of the fall prevention member 75 is shown in FIG. 9, and a rear view is shown in FIG.

  As shown in FIGS. 9 and 10, the first member 76 is a member in which a vertical cross section extending in the left-right direction is formed in an I shape in the present embodiment, and includes a mounting portion 76 a, a support portion 76 b, and a constrained portion 76 c. Yes. The attachment portion 76a is a horizontal plate-like portion that is fixed to the lower surface of the guide rail 8 with a bolt or the like. The constrained portion 76c is a horizontal plate-like member connected to the attachment portion 76a via the support portion 76b, and faces the lower surface of the guide rail 8 vertically with a gap between the attachment portion 76a. The support portion 76b is also formed in a plate shape and is along a vertical plane extending in the front-rear direction. The constrained portion 76c extends to at least one of the left and right sides of the support portion 76b. In this embodiment, the support portion 76b and the constrained portion 76c are connected in a T shape. When attaching the 1st member 76 to the guide rail 8 by welding etc., the attaching part 76a is unnecessary.

  The second member 77 is attached to the back surface of the load receiving base body 23 so that the position of the second member 77 corresponds to that of the first member 76 when the load receiving base 5 is in the retracted position, and the mounting portion 77a, the supporting portion 77b, and the restraining portion 77c. It has. The attachment portion 77a is a horizontal plate-like member that has a wider area left and right and forward than the restraint portion 77c, and is a bolt or the like that passes through a through hole (in this example, a long hole) 77d at the front and rear positions on both the left and right sides. It is fixed to the cargo receiving table main body 23. When attaching the 2nd member 77 to the receiving stand 5 by welding etc., the attaching part 77a is unnecessary. In the present embodiment, when the load receiving platform 5 moves to the storage position, the pressing roller 8e described above rides on a portion of the mounting portion 77a that extends to the front side of the restraining portion 77c (see FIG. 5).

  The rear portion of the attachment portion 77a is bent vertically to form an end wall 77e. The restraint part 77c is a horizontal plate-like member connected to the attachment part 77a via the left and right support parts 77b, and forms a box shape with the front side opened together with the support part 77b and the end wall 77e. The restraining part 77c faces the upper and lower sides of the back surface of the load receiving table main body part 23 with a gap therebetween and has a slit 77f. The slit 77f extends in the front-rear direction, similar to the guide rail 8, and is provided with a taper 77g at the entrance portion (opening side, that is, the front end portion), and the entrance portion of the slit 77f is widened.

  When the load receiving platform 5 is in the retracted position, the support portion 76b of the first member 76 is accommodated in the slit 77f, and at the same time, the first portion is disposed between the opposed surfaces of the restraining portion 77c of the second member 77 and the back surface of the load receiving table main body portion 23. The restrained portion 76c of the member 76 is accommodated. Hereinafter, this state is referred to as a “restrained state” of the fall prevention member 75, and a state where the first member 76 is detached from the second member 77 is referred to as a “release state” of the fall prevention member 75.

1-5. Power Unit As shown in FIG. 2 and the like, a power unit 26 and an operation device 27 are attached to the left bracket portion 11 of the slide drive portion 6. The power unit 26 is a power unit for driving the slide cylinder 14 and the lift cylinder 20. The load receiving table lifting device 4 can be operated by the operation device 27.

  FIG. 11 is a circuit diagram illustrating a configuration example of the power unit 26. The power unit 26 shown in the figure includes an electric motor 28, a hydraulic pump 29, an oil tank 30, a pressure oil supply passage 31, an ascending operation control valve 32, a pressure oil return passage 33, a descending operation control valve 34, and a flow rate control valve. 35, a main relief valve 36 and a conductor relay 37 are provided. The hydraulic pump 29 is driven by the electric motor 28 and discharges hydraulic oil sucked from the oil tank 30 to the discharge pipe 29a. The hydraulic oil discharged from the hydraulic pump 29 is supplied to the lift cylinder 20 via the pressure oil supply passage 31. The pressure oil supply passage 31 is provided with a control valve 32 for raising operation, and the control valve 32 for raising operation is opened and closed by a signal input to the solenoid 32a, so that the pressure oil supply passage 31 is communicated or cut off. The pressure oil return passage 33 is branched from the downstream side of the control valve 32 for raising operation in the pressure oil supply passage 31 and is connected to the oil tank 30. The pressure oil return passage 33 is provided with a control valve 34 for the lowering operation. The control valve 34 for the lowering operation is opened and closed by a signal input to the solenoid 34a, and the pressure oil return passage 33 is communicated or cut off. A flow rate control valve 35 is provided on the downstream side of the control valve 34 for the lowering operation in the pressure oil return passage 33. Further, a main relief valve 36 is provided in the discharge conduit 29a, and the maximum value of the pressure in the discharge conduit 29a is defined by the main relief valve 36. A conductor relay 37 is provided between the electric motor 28 and a battery (not shown).

  The power unit 26 also includes a pressure oil supply passage 38, a throttle valve 39, a check valve 40, a pressure oil supply passage 41, a drawing operation control valve 42, a pressure oil return passage 43, and a drawing operation control valve 44. . The pressure oil supply passage 38 branches from the discharge pipe 29 a of the hydraulic pump 29 and is connected to the rod side of the slide cylinder 14. A throttle valve 39 and a check valve 40 are provided in the pressure oil supply passage 38. The pressure oil supply passage 41 branches from the pressure oil supply passage 38 and is connected to the bottom side of the slide cylinder 14. The pressure oil supply passage 41 is provided with a drawing operation control valve 42. The drawing operation control valve 42 is opened and closed by a signal input to the solenoid 42a, and the pressure oil supply passage 41 is communicated or cut off. The pressure oil return passage 43 branches from the pressure oil supply passage 41 on the downstream side of the drawing operation control valve 42 and is connected to the oil tank 30. The pressure oil return passage 43 is provided with a control valve 44 for drawing operation, and the control valve for drawing operation 44 is opened / closed by a signal input to the solenoid 44a to connect or block the pressure oil return passage 43.

  In the present embodiment, the bypass passage 71 is branched from the discharge pipe 29a at the position downstream of the main relief valve 36 and upstream of the drawing operation control valve 42 and the drawing operation control valve 44. It is connected to the return passage 43. The bypass passage 71 is provided with a sub relief valve 73 and a switching valve 72. The switching position of the switching valve 72 is switched to a communication position (upper position in the figure) or a blocking position (lower position in the figure) by a command signal to the solenoid 72a. Depending on the switching position of the switching valve 72, the flow of pressure oil to the sub relief valve 73 is communicated or blocked. The switching valve 72 is provided on the upstream side of the sub-relief valve 73, but may be provided on the downstream side. The relief pressure (for example, about 6 MPa) of the sub relief valve 73 is set lower than the relief pressure (for example, about 20 MPa) of the main relief valve 36. When the switching valve 72 is switched to the communication position and connected to the discharge pipe 29a, the maximum value of the pressure oil in the discharge pipe 29a is defined to be lower than the relief pressure of the main relief valve 36.

  Further, a pressure sensor 74 is provided on the discharge pipe 29a of the hydraulic pump 29 as a pressure sensor that detects that the load receiving platform 5 is pressed against the guide rail 8 via the pressing roller 8e. When the load receiving platform 5 is pressed against the guide rail 8, the pressure in the discharge pipe 29 a rises. Therefore, if the detected value of the pressure sensor 74 exceeds a threshold value (set value), it is determined that the load receiving platform 5 is in contact with the guide rail 8. it can.

1-6. Control Device FIG. 12 is a functional block diagram showing an example of the configuration of the control device provided in the cargo receiving table lifting device 4 together with peripheral devices. The control device 45 shown in FIG. 12 is provided on the vehicle side (or in the power unit 26). The control device 45 is connected to a power source (battery) 57 of the cargo receiving platform lifting / lowering device 4 via a power switch 58, and the power switch 58 switches on / off of the power source. The power switch 58 can be installed, for example, in the cab 2 of the vehicle, the power unit 26, or the like. The operation signal input to the control device 45 includes a wired signal output from the operation device 27 and a wireless signal output from a wireless operation device 46 such as a remote controller.

  The operation device 27 is, for example, of a pendant operation type including a push button type raising operation switch 47A and a lowering operation switch 47B. The operation device 27 outputs an operation signal corresponding to the operation of the raising operation switch 47A or the lowering operation switch 47B to the control device 45 via a cable or the like.

  The operating device 46 includes a raising operation switch 48A, a lowering operation switch 48B, a power switch 48C, and a transmission unit 49. The raising operation switch 48A, the lowering operation switch 48B, and the power switch 48C are push button type switches. The transmission unit 49 generates serial data such as the ON / OFF state of the raising operation switch 48A or the lowering operation switch 48B, and transmits the serial data as a radio signal. The operating device 46 can be carried by the operator, but may be stored in the cab 2 or the loading platform 3 or the like.

  The control device 45 includes an input unit 50, a reception unit 51, a storage unit (memory) 52, a calculation unit (CPU) 53, an output unit 54, and a timer 55. The input unit 50 is a functional unit that inputs detection signals from the rear end sensor 15, the intermediate sensor 16, the gate sensor 56 and the pressure sensor 74, and an operation signal from the operation device 27. The receiving unit 51 is a functional unit that receives a wireless operation signal from the operation device 46. The storage unit 52 is a functional unit that stores a control program (for example, a program based on sequence control, timer control, or the like) and a control threshold value. The calculation unit 53 is a functional unit that executes calculation processing according to the control program stored in the storage unit 52 and generates a command signal or the like that instructs the operation of the cylinders 14 and 20. The output unit 54 is a functional unit that appropriately outputs the command signal generated by the calculation unit 53 to the solenoids 32 a, 34 a, 42 a, 44 a, 72 a of each control valve 32, 34, 42, 44, 72 and the conductor relay 37. The timer 55 is a time measuring means. In this embodiment, the timer 55 is used for measuring an elapsed time after the gate sensor 56 is turned on during the storing operation.

2. Operation 2-1. Outline FIG. 13 and FIG. 14 are schematic diagrams in which the relationship between the posture and the input / output signals during the unfolding operation and the storage operation of the load receiving table lifting / lowering device 4 and the input / output signals are tabulated. As shown in these drawings, the unfolding operation of the load receiving platform lifting / lowering device 4 is performed by sequence control in which the first drawing, first lowering, second pulling, and second lowering procedures are sequentially executed. The first drawer is an operation of pulling the load receiving platform 5 from the retracted position to the intermediate position to bring the fall prevention member 75 from the restrained state into the released state, and is lowered on condition that no detection signal is input from any sensor. This is executed by operating the operation switch 47B or 48B. The first lowering is an operation of lowering the load receiving platform 5 pulled out to an intermediate position to an intermediate height, and is executed by operating the lower operation switch 47B or 48B on condition that a detection signal is input from the intermediate sensor 16. . The second drawer is an operation of pulling the load receiving platform 5 to the rear end position at an intermediate height, and is executed by operating the lower operation switch 47B or 48B on condition that a detection signal is input from the gate sensor 56. The second lowering is an operation of lowering the load receiving platform 5 from the intermediate height to the ground contact height at the rear end position, and the operation of the lowering operation switch 47B or 48B is performed on condition that a detection signal is input from the rear end sensor 15. It is executed by. Through these series of procedures, the control device 45 instructs the operations of the lift cylinder 20 and the slide cylinder 14 so that the load receiving platform 5 moves stepwise from the storage position to the grounding position.

  Similarly, the storing operation is also based on sequence control in which the first ascending, first retracting, second ascending, and second retracting procedures are sequentially executed. The first ascending operation is an operation of stopping the slider 9 at the rear end position and raising the load receiving platform 5 from the ground contact height to the intermediate height. The operation switch is raised on condition that a detection signal is input from the rear end sensor 15. It is executed by the operation of 47A or 48A. The first pull-in is an operation in which the load receiving platform 5 is advanced to an intermediate position by moving the load receiving platform 5 to an intermediate position, and the load receiving platform 5 is pulled to the lower side of the vehicle frame 1, and the detection signal is inputted from the gate sensor 56. This is executed by operating the raising operation switch 47A or 48A. The second ascending operation is an operation of stopping the slider 9 at the intermediate position and raising the load receiving platform 5 to the storage height and pressing it against the guide rail 8. The raising operation switch is provided on the condition that the detection signal is inputted from the intermediate sensor 16. It is executed by the operation of 47A or 48A. The second pull-in is an operation in which the load receiving platform 5 is advanced to the front end position at the retracted height, the load receiving platform 5 is retracted to the retracted position, and the fall prevention member 75 is shifted to the restrained state. The second pull-in is started by the operation of the raising operation switch 47A or 48A on condition that the detection signal is inputted from the pressure sensor 74, and also after the detection signal is not inputted from any sensor. It is executed by the operation of 47A or 48A. Through these series of procedures, the control device 45 instructs the operations of the lift cylinder 20 and the slide cylinder 14 so that the load receiving platform 5 moves stepwise from the ground contact position to the storage position. Next, the control procedure will be specifically described.

2-2. Control Procedure FIG. 15 is a flowchart showing a control procedure of the load receiving table lifting device by the control device 45. The control device 45 repeatedly executes the procedure of FIG. 15 every cycle time ΔT while the power is on. That is, the load receiving table lifting / lowering device 4 operates only while operating the operating device 27 or 46.

(1) Operation determination When the control device 45 starts the procedure of FIG. 15, the operation device 27 or 46 has performed a raising operation (operation of the raising operation switch 47A or 48A) or a lowering operation (operation of the lowering operation switch 47B or 48B). Determine whether or not In the example of FIG. 15, the control device 45 first determines whether or not the lowering operation has been performed (step S100), and if so, the procedure proceeds to step S101 to execute any procedure of the unfolding operation for the cycle time ΔT. finish. If the lowering operation has not been performed, it is determined whether the raising operation has been performed (step S200). If the lowering operation has been performed, the procedure proceeds to step S201, and one of the storage operations is executed for the cycle time ΔT, and the process ends. If neither the raising operation nor the lowering operation is performed, the control device 45 moves the procedure to Step S300 and stops the load receiving table lifting device 4 without driving (the lift cylinder 20 and the slide cylinder 14 are not expanded or contracted).

(2) Unfolding operation-Condition determination When the lowering operation is performed and the procedure proceeds to step S101, the controller 45 first determines whether a detection signal is input from the rear end sensor 15 in the example of FIG. If the detection signal is not input from the rear end sensor 15, the control device 45 proceeds to step S <b> 102 and determines whether the detection signal is input from the gate sensor 56. If the detection signal is not input also from the gate sensor 56, the control apparatus 45 moves a procedure to step S103, and determines whether the detection signal is input from the intermediate sensor 16.

First Drawout If no detection signal is input as a result of the determination in steps S101 to S103, the control device 45 moves the procedure to step S104, executes the first withdrawal for the cycle time ΔT, and executes FIG. End the procedure.

  Details of the process of the first drawer (step S104) will be described. In step S104, the controller 45 energizes the coil 37a of the conductor relay 37 (FIG. 11). When the coil 37a is excited, the contact point 37b is closed, and the electric motor 28 and the hydraulic pump 29 are driven by power supply from the battery. At the same time, the control device 45 excites the solenoid 42a and demagnetizes the solenoid 44a, opens the drawing operation control valve 42 and closes the drawing operation control valve 44. As a result, the pressure oil from the hydraulic pump 29 is supplied to the bottom side of the slide cylinder 14 via the pressure oil supply passage 41, and the slide cylinder 14 extends due to the pressure receiving area difference from the rod side. By repeating the procedure of step S104, the slider 9 moves backward from the front end position at the storage height.

First descent If a detection signal is input from the intermediate sensor 16 while the first drawing procedure (step S104) is repeated, the control device 45 switches the process from step S104 to step S105, and only the cycle time ΔT. The first lowering operation is executed, and the procedure of FIG. 15 is finished.

  Details of the first descent (step S105) processing will be described. In step S105, the control device 45 stops energizing the coil 37a. When the coil 37a is demagnetized, the contact 37b is opened, and the electric motor 28 and the hydraulic pump 29 are stopped. At the same time, the control device 45 demagnetizes the solenoid 32a to excite the solenoid 34a, closes the ascent operation control valve 32, and opens the ascent operation control valve 34. As a result, the bottom side of the lift cylinder 20 communicates with the oil tank 30 via the pressure oil return passage 33, and the lift cylinder 20 is contracted by the weight of the load cradle 5 and the load cradle 5 is lowered. By repeating the procedure of step S105, the receiving platform 5 is lowered from the storage height at the intermediate position.

-Second drawer If a detection signal is input from the gate sensor 56 while the first descending procedure (step S105) is repeated, the control device 45 switches the process from step S105 to step S106, and only the cycle time ΔT. The second drawing is executed and the procedure of FIG. 15 is terminated. The details of the process of the second drawer (step S106) are the same as those of the first drawer (step S104). By repeating the procedure of step S106, the slider 9 moves backward from the intermediate position at the intermediate height.

Second descent If a detection signal is input from the rear end sensor 15 while the second drawing procedure (step S106) is repeated, the control device 45 switches the process from step S106 to step S107, and the cycle time ΔT. Only the second lowering operation is executed, and the procedure of FIG. 15 is finished. The details of the second lowering (step S107) are the same as those of the first lowering (step S105). By repeating the procedure of step S107, the load receiving platform 5 is lowered from the intermediate height at the rear end position. When the load receiving platform 5 comes into contact with the ground by repeating the first lowering, the operator pulls the load receiving platform main body 23 to expand the load receiving platform 5 horizontally so that the cargo handling work can be performed.

  Note that the operation of lowering the cargo receiving platform 5 in the cargo handling operation has the same processing contents as the second lowering, and is executed by a lowering operation on condition that a detection signal is input from the rear end sensor 15. The only difference from the second descent is whether the receiving platform 5 is folded.

(3) Storage Operation-Condition Determination When the raising operation is performed and the procedure proceeds to step S201, the control device 45 first determines whether a detection signal is input from the intermediate sensor 16 in the example of FIG. If the detection signal is not input from the intermediate sensor 16, the control device 45 moves to step S <b> 202 and determines whether the detection signal is input from the gate sensor 56. If the detection signal is not input also from the gate sensor 56, the control apparatus 45 moves to step S203 and determines whether the detection signal is input from the rear end sensor 15. If the detection signal is input from the intermediate sensor 16 in the previous step S201, the control device 45 moves the procedure to step S209 and determines whether the detection signal is input from the pressure sensor 74.

First rise If the detection signal is input from the rear end sensor 15 as a result of the determination in steps S201 to S203 and S209, the control device 45 moves the procedure to step S204 and increases the first rise by the cycle time ΔT. Execute and finish the procedure of FIG. If the detection signal is input from the gate sensor 56, the control device 45 moves the procedure to step S205, and sets the cycle time ΔT to the elapsed time T after the gate sensor 56 is turned on based on the signal of the timer 55. Add (T = T + ΔT). Subsequently, the control device 45 determines whether or not the time T has reached the set time T0 in step S206. The set time T0 is a value that is set in advance and stored in the storage unit 52, and receives the load from the lower limit position to the intermediate position of the detection range of the gate sensor 56 (the set height range of the load receiving platform 5 including the intermediate height). It is a short time required to raise the platform 5. If the time T has not reached the set time T0, the control device 45 shifts the procedure to step S204, executes the first increase by the cycle time ΔT, and ends the procedure of FIG. That is, even after the gate sensor 56 is turned on (from the time when it is detected based on the signal of the gate sensor 56 that the receiving platform 5 has reached the lower limit of the set height range), until the set time T0 elapses. The first rise continues for a short period of time. As a result, the cargo receiving platform 5 rises to an intermediate region within the set height range.

  Details of the first ascent (step S204) processing will be described. In step S204, the control device 45 energizes the conductor relay 37 (FIG. 11) to drive the electric motor 28 and the hydraulic pump 29. At the same time, the control device 45 excites the solenoid 32a and demagnetizes the solenoid 34a, opens the ascending operation control valve 32 and closes the descending operation control valve 34. As a result, the pressure oil from the hydraulic pump 29 is supplied to the bottom side of the lift cylinder 20 via the pressure oil supply passage 31, and the lift cylinder 20 extends. By repeating the procedure of step S204, the load receiving platform 5 is raised from the ground contact position at the rear end position.

  In the case of storing the load receiving stand 5, it is necessary to perform a preliminary work for leaning the load receiving stand main body portion 23 on the support roller 12 at the ground contact position. Whether the storage operation or the cargo handling operation is performed by the lifting operation is determined by the presence or absence of prior work. If the prior work is not performed, the gate sensor 56 does not enter even if the cargo receiving platform 5 moves up and down, so that step S202 is not satisfied, and the cargo receiving work 5 is raised to the height of the loading platform at the rear end position to perform the cargo handling operation. be able to.

First pull-in When the detection signal is input from the gate sensor 56 while the first ascending procedure (step S204) is repeated and the elapsed time T reaches the set time T0, the control device 45 performs steps from step S204 to step S204. The process is switched to S207. The controller 45 executes the first pull-in operation for the cycle time ΔT in step S207, resets the elapsed time T (T = 0) in the subsequent step S208, and ends the procedure of FIG.

  Details of the first pull-in (step S207) processing will be described. In step S207, the control device 45 excites the coil 37a of the conductor relay 37 and drives the electric motor 28 and the hydraulic pump 29. At the same time, the control device 45 excites the solenoid 44a to demagnetize the solenoid 42a, opens the pull-in operation control valve 44, and closes the pull-out operation control valve 42. Accordingly, the pressure oil from the hydraulic pump 29 is supplied to the rod side of the slide cylinder 14 via the pressure oil supply passage 38, and the pressure oil discharged from the bottom side of the slide cylinder 14 is supplied to the oil tank via the pressure oil return passage 43. Returning to 30, the slide cylinder 14 contracts. By repeating the procedure of step S207, the slider 9 advances from the rear end position at the intermediate height.

Second rise If the detection signal is input from the intermediate sensor 16 while the first pull-in procedure (step S207) is repeated, the control device 45 switches the process from step S207 to step S209, and from the pressure sensor 74 It is determined whether a detection signal is input. If the pressure sensor 74 is off, the control device 45 moves the procedure to step S210, executes the second increase by the cycle time ΔT, and ends the procedure of FIG. The processing of the second rise (step S210) is the same as the first rise (step S204). By repeating the procedure of step S210, the receiving platform 5 is raised from the intermediate height at the intermediate position.

Second pull-in If a detection signal is input from the pressure sensor 74 while the second ascending procedure (step S210) is repeated, the control device 45 switches the process from step S210 to step S211, and only the cycle time ΔT. The second drawing is executed and the procedure of FIG. 15 is terminated. Note that the pressure sensor 74 can be configured to be turned on when the contact pressure between the load receiving platform 5 and the guide rail 8 becomes a predetermined pressure (for example, 40 MPa) or more. When a sensor that outputs a detection signal corresponding to the detected pressure is used for the pressure sensor 74, the detection signal of the pressure sensor 74 is compared with a predetermined pressure by the control device 45, and when the detection signal becomes equal to or higher than the predetermined pressure, It can also be configured to determine that is turned on. The intermediate sensor 16 is turned off while repeating Step 211. In this case, the procedure of Step S211 is continuously executed via the processing of Steps S210 to S203. The details of the second pull-in process (step S211) are the same as the first pull-in process (step S207). While the pressure sensor 74 is on, the control device 45 excites the solenoid 72a to open the switching valve 72 and lower the relief pressure of the hydraulic circuit in parallel with the second pull-in process (step S211). By repeating the procedure of step S211, the load receiving platform 5 moves forward from the intermediate position at the storage height, the slider 9 reaches the storage position, and the fall prevention member 75 shifts from the released state to the restrained state.

3. Effect (1) Smoothness of storing operation If the rear sensor 15 is not turned off when the gate sensor 56 is turned off during the first pull-in operation, the first ascending operating condition is satisfied. The lifting operation of the load receiving platform 5 can be performed even for a moment. In this case, the smoothness of the storing operation is reduced. On the other hand, in the present embodiment, the first elevation is continued for a set time T0 slightly after the gate sensor 56 is turned on, so that the set height range including the intermediate height (the detection range of the gate sensor 56). The cradle 5 rises to the middle region. The gate sensor 56 is unlikely to be turned off even if the load receiving platform 5 is shaken up and down during the first pull-in. As a result, it is possible to suppress an unintended ascent operation (a first ascent again) due to the gate sensor 56 being turned off during the first pull-in operation, and to reduce the smoothness of the storing operation of the load receiving platform 5. Can be suppressed.

  For example, in order to suppress a collision sound when the slider 9 reaches the rear end position during the unfolding operation, the detection range of the rear end sensor 15 is widened forward, and the reverse speed is reached when the slider 9 enters a range of a predetermined distance from the rear end position. It is also conceivable to adopt a configuration that reduces In this case, since the time from the start of the first pull-in during the storage operation to the turn-off of the rear end sensor 15 is extended, the possibility of an unexpected re-raising operation increases. Thus, the occurrence of an unexpected re-lifting operation can be suppressed.

(2) Certainty of storage operation, etc. As described above, in this embodiment, the storage operation is performed through the first rise, the first pull-in, the second rise, and the second pull-in. When the load receiving platform 5 is moved to the storage position, the load receiving platform 5 is pressed against the guide rail 8 by passing through the second ascending operation. At this stage, the load receiving platform 5 does not rattle due to contact with the guide rail 8. Accordingly, the load receiving platform 5 can be accurately stored at the time of the second retracting operation without being affected by fluctuations in the operating speed of the slide cylinder 14 and the lift cylinder 20 due to the viscosity of the pressure oil. It is possible to prevent the fall prevention member 75 from failing to enter the restraint state due to the variation in the height of the load receiving platform 5. In addition, the gap between the flanges 78 and 79 of the fall prevention member 75 can be reduced, and the descending width of the load receiving platform 5 can be suppressed to an extremely small distance even if pressure oil leaks to the lift cylinder 20.

(Second Embodiment)
FIG. 16 is a flowchart showing a control procedure by the control device provided in the retractable cargo receiver lifting device according to the second embodiment of the present invention. As in the first embodiment, the control device 45 repeatedly executes the procedure of FIG. 16 every cycle time ΔT while the power is on. Further, the difference from the flowchart of the first embodiment shown in FIG. 15 is that steps S205, S206, and S208 of the first embodiment are omitted and steps S212 to S214 are added in the storage operation procedure. It is only a point that has been done. The other steps are the same as those in the flowchart of FIG. 15, and the same step numbers as those in FIG. 15 are used in FIG.

  In the present embodiment, when the gate sensor 56 is on in step S202, the control device 45 moves the procedure to step S212, sets the flag F to 1, and moves the procedure to step S207 to execute the first pull-in. The flag F is normally set to 0, and switches from 0 to 1 when the gate sensor 56 is turned on. When the gate sensor 56 is off in step S202, the control device 45 determines whether or not the flag F = 0 in step S213 before moving the procedure to step S203. Since F = 0 during the first ascent that has not reached the intermediate height, the controller 45 moves the procedure from step S213 to step S203. Further, when the intermediate sensor 16 is ON in step S201, the control device 45 returns the flag setting to 0 in step S214 (F = 0) before moving the procedure to step S209. Other procedures are the same as those in the first embodiment.

  In the present embodiment, F = 1 is set when the gate sensor 56 is turned on once through the first rise. Since the flag F remains F = 1 until the intermediate sensor 16 is turned on, even if the gate sensor 56 is turned off during the first pull-in, the procedure proceeds to step S207 via steps S213 and S212. The first rise is not executed and the first pull-in is executed. Therefore, when the first pull-in is started, the controller 45 does not command an unexpected rise of the load receiving platform 5, and the first pull-in is performed until the slider 9 reaches the intermediate position regardless of whether the gate sensor 56 is turned on or off. Is done. Therefore, the same effect as the first embodiment can be obtained. In the present embodiment, since the gate sensor 56 is allowed to be turned off during the first pull-in, the detection range of the gate sensor 56 is narrower than that in the first embodiment.

(Modification)
In the present embodiment, the case where the cargo receiving platform 5 is stored by the procedure of the first lifting, the first pulling-in, the second lifting, and the second pulling-in is described as an example, but the lifting operation during the storing operation is described. Or the number of pull-in operations may be changed. The same applies to the unfolding operation. For example, the intermediate sensor 16 is omitted and the gate sensor 56 is turned on at the retracted height, and after raising the load receiving platform 5 from the ground contact height to the retracted height at the rear end position, the rear end position is changed to the front end position. The slider 9 may be advanced until the storage operation is completed. In this case as well, when switching from the ascending operation to the retracting operation, the same effect can be obtained by switching to the retracting operation by executing the ascending operation for the set time T0 after the gate sensor 56 is turned on as in the first embodiment. It is done. When the second embodiment is applied, for example, a front end sensor that detects the slider 9 at the front end position is provided instead of the intermediate sensor 16, and the gate sensor 56 is turned on at the storage height. Thus, when the pull-in operation is started, the pull-in operation can be executed by the raising operation regardless of whether the gate sensor 56 is turned on or off until the front end sensor is turned on, and the same effect can be obtained. In addition, the same control can be applied when switching from the ascending operation to the retracting operation as an operation sequence in which at least one of the ascending operation and the retracting operation is increased three times or more in the storing operation.

  In the first and second embodiments, an angle sensor is applied to the gate sensor 56 to detect that the load receiving platform 5 has reached the intermediate height based on the change in the angle of the load receiving table main body 23 during the storing operation. Although it is configured, it can be replaced with a proximity sensor. Although the rear end sensor 15 is provided, the rear end sensor 15 can be omitted when the slider 9 is visually confirmed to be in the rear end position. In this configuration, if the storage operation is completed by each one ascending and retracting operation as described above, the gate sensor 56 is simply lifted when it is off and retracted when it is on. Control can be applied. In this case, if the gate sensor 56 is turned off during the pulling-in operation regardless of the front and rear positions of the load receiving table, the condition changes to the ascending operation. Even in such a case, the effect can be obtained by applying the present invention.

  Moreover, although the configuration in which the unfolding operation and the storing operation are executed only while the raising operation or the lowering operation is performed is not limited thereto. For example, the second pull-in can be performed forcibly regardless of whether there is a raising operation or a lowering operation until it is completed (for example, for a predetermined time). In this case, the load receiving platform 5 can be reliably pulled to the storage position and the fall preventing member 75 can be shifted to the restrained state. In this case, for example, a stop switch 47D or 48D (see FIG. 12) for instructing the operation device 27 or 46 to stop the second pull-in may be provided so that the forced second pull-in can be interrupted.

  Further, in order to raise and lower the load receiving platform 5 in a state where the slider 9 is surely at the rear end position, the control valve 42 for drawing operation is switched to the communication position during the second lowering, first raising or cargo handling work, and the stopper 8i. In addition, the striker 9n may be configured to press against each other. In addition, the pull-in operation control valve 44 can be instantaneously switched to the communication position when the slider 9 starts to be pulled out, and the slide cylinder 14 can be depressurized.

  Further, in the present embodiment, the case where the retractable load receiving device lifting device for storing the load receiving device on the lower side of the vehicle frame is described as an example. However, there is a retractable load receiving device lifting device of this type that can select a retracted posture in which the load receiving stand is raised at the rear of the load carrier in addition to the retracted posture stored in the lower side of the vehicle frame. Even in a retractable load receiving device lifting apparatus adopting such two storage postures, the same effect can be obtained by applying the present invention when storing the load receiving table under the vehicle frame.

  In addition, the case where the present invention is applied to the retractable load receiving device lifting / lowering device that pulls the load receiving stand 5 to the rear side of the vehicle and performs the cargo handling work has been described as an example, but the load receiving stand is pulled out to the left or right side of the vehicle. The same effect can be obtained even if the present invention is applied to a retractable load receiving table lifting apparatus that performs a cargo handling operation. In addition, the configuration in which the slider 9 is driven by a roller with respect to the guide rail 8 has been described as an example. However, the slider is supported via a pad with respect to the rail, and the slider is moved by sliding the pad with respect to the rail. There is also a loading platform lifting device to be moved. Naturally, the present invention can be applied to such a load receiving table lifting apparatus.

DESCRIPTION OF SYMBOLS 1 Car frame 4 Retractable load receiving device raising / lowering device 5 Load receiving stand 8 Guide rail 9 Slider 14 Slide cylinder 45 Control device 16 Intermediate sensor (2nd sensor)
17 First arm (arm)
18 Second arm (arm)
19 Third arm (arm)
20 Lift cylinder 56 Gate sensor (sensor, first sensor)

Claims (4)

A load receiving table, a guide rail provided at a lower portion of the vehicle, a slider that moves along the guide rail, a slide cylinder that moves the slider, an arm that connects the load receiving table to the slider so as to be movable up and down, and the load receiving table In a retractable load receiving device lifting device having a lift cylinder for moving up and down,
A sensor for detecting a vertical position of the load receiving table;
A control device for controlling the lift cylinder and the slide cylinder;
When storing the cargo cradle, the control device continues the lift cylinder for a set time from the time when it is detected based on the signal of the sensor that the cargo cradle has reached the lower limit of the set height range. The retractable load receiving device lifting / lowering device is configured to drive the slide cylinder and retract the load receiving device after the load receiving device is driven to raise the load receiving device to an intermediate region of the set height range.   2. The retractable load receiving device lifting apparatus according to claim 1, wherein the control device stores the load receiving table through a first ascending operation, a first retracting operation, a second ascending operation, and a second retracting operation. A retractable load receiving device lifting and lowering device that executes and switches from the first ascending operation to the first retracting operation based on a signal from the sensor. A load receiving table, a guide rail provided at a lower portion of the vehicle, a slider that moves along the guide rail, a slide cylinder that moves the slider, an arm that connects the load receiving table to the slider so as to be movable up and down, and the load receiving table In a retractable load receiving device lifting device having a lift cylinder for moving up and down,
A first sensor for detecting a vertical position of the load receiving table;
A second sensor for detecting a horizontal position of the slider;
A control device for controlling the lift cylinder and the slide cylinder;
When storing the cargo cradle, the control device stops the lift cylinder when it is detected that the cargo cradle has reached a set vertical position based on a signal from the first sensor, and then the second cylinder is stopped. The slide cylinder is driven according to an operation regardless of the signal of the first sensor until the slider is detected to have reached the set horizontal position based on the sensor signal, and the set horizontal direction. A retractable load receiving device lifting device, wherein the load receiving device is pulled to a position.   4. The retractable load receiving device lifting apparatus according to claim 3, wherein the control device stores the load receiving table through a first ascending operation, a first retracting operation, a second ascending operation, and a second retracting operation. At this time, the first ascending operation is switched to the first retracting operation based on the signal from the first sensor, and the second retracting operation is switched from the first retracting operation based on the signal from the second sensor. The retractable load receiving device elevating device is characterized by switching to the ascending operation.

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