Gate opening / closing mechanism

Abstract

To provide a gate opening / closing device which can perform manual gate opening / closing operation with a less load by switching to manual operation, even when an electric actuator is inoperable.SOLUTION: A gate opening / closing device X has a link mechanism L for supporting opening / closing operation of a gate A, a drive part 3 having an electric actuator 31 for driving the link mechanism L in a lower space of a load-carrying platform T1, and a mechanical auxiliary drive part 4 for assisting drive force by the drive part 3, and includes an electric / manual switching part K for individually connecting the link mechanism L to the electric actuator 31 and the auxiliary drive part 4, selectively connecting or releasing a connection place between the link mechanism L and the electric actuator 31, and thereby switching drive force to the link mechanism L.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The present invention relates to a gate opening / closing mechanism for opening and closing a gate provided on the bed of a cargo vehicle such as a truck. [Background technology]

[0002] The transportation industry accounts for approximately 5% of Japan's GDP, and the logistics industry, which accounts for over 60% of the transportation industry market, is expanding due to environmental changes and is expected to continue to grow significantly.However, the logistics industry is seeking to automate truck loading and unloading operations to address the labor shortage of truck drivers and improve safety.

[0003] Conventionally, workers have operated the gate opening and closing operations by themselves with assistance from a manual opening and closing assist device (see, for example, Patent Document 1). However, when opening and closing the gate with assistance from the manual opening and closing assist device, a certain amount of force is required to lift the gate (switch it from the open state to the closed state), which places a burden on the worker. Even when an attempt is made to realize an automatic gate opening and closing mechanism by adding an electric mechanism to a conventional manual opening and closing assist device, the gate may suddenly tip over (start opening) when moving the gate from a closed state to the open state due to the configuration of the conventional manual opening and closing assist device, making it difficult to ensure smooth opening and closing of the gate. Furthermore, electric gate opening and closing devices currently installed on many trucks are configured to open and close the gate by changing the angle of an electric actuator as a drive arm rotates in accordance with the advancement and retreat of a rod using the torque of a DC motor (see Patent Document 2).

[0004] Furthermore, if a truck has a protruding portion on the side, that protruding portion determines the width of the vehicle. Therefore, if the gate opening / closing mechanism is positioned so that it protrudes further to the side than the loading platform, the width of the loading platform will be reduced by that amount, which will in turn reduce the size of the loading platform and the load capacity. Therefore, conventional gate manual opening / closing assist devices are configured so that they do not protrude from the side of the truck. Therefore, the present applicant has developed a gate opening / closing device that can automatically open and close the gate at the same size as conventional gates, and in particular, prevents and suppresses the gate from suddenly opening, thereby increasing safety and enabling smooth opening and closing of the gate (see Patent Document 3). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 11-291956 [Patent Document 2] Japanese Patent Application Publication No. 10-29565 [Patent Document 3] Patent Publication No. 2024-015814 Summary of the Invention [Problem to be solved by the invention]

[0006] In the configuration of an electric gate opening / closing device described in Patent Document 2, if the electric actuator breaks down, there is a problem in that the gate cannot be opened or closed at all. Even if an attempt is made to open or close the gate manually when the electric actuator is not working, a large amount of force is required to manually lift the gate, etc., because there is no electrical or mechanical assistance.

[0007] The gate opening / closing device described in Patent Document 3 is equipped with an electric actuator that rotates a fixed shaft via a power transmission mechanism (for example, a mechanism using a sprocket or chain installed axially on the fixed shaft or drive motor) as a mechanism for driving a link mechanism that supports the gate opening / closing operation, and an auxiliary power spring mechanism that provides auxiliary power for the gate opening / closing operation, but no consideration is given to what would happen if the electric actuator became inoperable, and no details of the auxiliary power spring mechanism are disclosed.

[0008] The present invention has been made with an eye on such problems, and aims to provide a gate opening / closing device that has an electric actuator as a drive unit, and that can switch to manual operation even if the electric actuator becomes inoperable due to a malfunction or the like, and that can assist manual gate opening / closing operation with a mechanical auxiliary drive force. [Means for solving the problem]

[0009] That is, the present invention relates to a gate opening / closing mechanism that automatically opens and closes a gate provided on the bed of a vehicle such as a freight vehicle. Examples of vehicles with beds include trucks, trailers, dump trucks, etc. A gate is also called a gate, and specific examples include a side gate that defines the side of the bed and a tailgate that defines the rear of the bed.

[0010] The gate opening / closing device of the present invention has a link mechanism that supports the opening and closing operation of the gate, a drive unit equipped with an electric actuator that drives the link mechanism in the space below the loading platform, and a mechanical auxiliary drive unit that assists the drive force from the drive unit, and is characterized by having an electric / manual switching unit that individually connects the link mechanism to the electric actuator and the auxiliary drive unit, and switches the drive force for the link mechanism by selectively connecting or disconnecting the connection points between the link mechanism and the electric actuator.

[0011] In such a gate opening / closing device according to the present invention, even if the electric actuator of the drive unit is not energized or breaks down and becomes inoperable, the link mechanism and the auxiliary drive unit remain connected even if the connection between the link mechanism and the electric actuator is released in the electric / manual switch, so assistance from the mechanical auxiliary drive unit can be obtained when manually opening and closing the gate, reducing the manual load required for lifting and supporting the gate. On the other hand, when the electric actuator is operating normally, the connection between the link mechanism and the electric actuator is maintained in the electric / manual switch, so the drive force of the electric actuator required to open and close the gate is reduced by the drive force from the auxiliary drive unit, thereby saving on required power consumption.

[0012] In such a gate opening / closing device of the present invention, if the electric / manual switching unit is configured so that the link mechanism and the electric actuator are pivotally connected by a pin that can be manually inserted and removed, the gate opening / closing operation can be easily switched between electric and manual.

[0013] Furthermore, by providing a retaining member that can be manually attached and detached by elastic engagement with the pin, the pin can be easily inserted and removed manually by manually attaching and detaching the retaining member, and by attaching the retaining member while the link mechanism and the electric actuator are connected by the pin, the gate can be safely opened and closed using the electric actuator.

[0014] Furthermore, by providing the auxiliary drive unit with an elastic member that applies elastic force to the link mechanism, it is possible to appropriately realize a mechanical auxiliary drive unit that assists the drive unit in providing driving force to the link mechanism when operated electrically, and assists in opening and closing the tilt manually when operated manually. [Effects of the Invention]

[0015] According to the gate opening / closing device of the present invention, even if the electric actuator of the drive unit becomes inoperable, the electric / manual switch releases the connection between the link mechanism and the electric actuator, and the auxiliary drive unit, which remains connected to the link mechanism, functions to provide assistance from the mechanical auxiliary drive unit when manually opening and closing the gate, thereby reducing the manual load required for lifting and supporting the gate.On the other hand, if the electric actuator is operating normally, maintaining the connection between the link mechanism and the electric actuator in the electric / manual switch allows the driving force required to open and close the gate to be shared between the electric actuator and the auxiliary drive unit, which also leads to power consumption savings. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is an overall schematic diagram of a freight vehicle equipped with a gate opening / closing device according to an embodiment of the present invention; [Figure 2] 2 is a diagram schematically showing a gate opening / closing device and its peripheral devices according to the embodiment; FIG. [Figure 3] FIG. [Figure 4] 3A and 3B are a right side view and a left side view, respectively, showing the gate opening / closing device. [Figure 5] 3A and 3B are front and rear views showing the gate opening / closing device. [Figure 6] 3A and 3B are plan and bottom views showing the gate opening / closing device. [Figure 7] FIG. 4 is a perspective view showing the link mechanism in the gate opening / closing device as viewed from diagonally above right. [Figure 8] FIG. 4 is a perspective view showing the link mechanism in the gate opening / closing device as viewed from diagonally below on the left side. [Figure 9] 10 is a right side view (with the frame removed) showing the gate opening / closing device in a closed state with the gate in a deployed position and the link mechanism in a deployed position. FIG. [Figure 10] An overview of the area around the electric / manual switch in the gate opening / closing device. [Figure 11]3 is a schematic view showing an auxiliary drive unit in the gate opening / closing device. FIG. [Figure 12] 4A and 4B are diagrams showing the deployed position of the link mechanism and the restrained state of the locking mechanism in the gate opening / closing device. [Figure 13] 10A and 10B are diagrams showing the stored position of the link mechanism and the released state of the lock mechanism in the gate opening / closing device. [Figure 14] 10A to 10C are diagrams showing the process of deploying / storing the link mechanism in the gate opening / closing device. [Figure 15] 4 is a diagram showing an intermediate state between the closed state and the open state of the gate in the gate opening / closing device. FIG. [Figure 16] 3 is a diagram showing the gate open state of the gate opening / closing device. FIG. [Figure 17] 4A and 4B are diagrams illustrating the driving force required to open and close the gate in the gate opening / closing device. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The gate opening / closing device X according to this embodiment is mounted on, for example, a cargo vehicle T (truck) shown in FIG. 1, so that the gate A of the loading platform T1 can be automatically opened and closed.

[0018] The truck T is a large truck (e.g., a 25-ton truck) equipped with a truck body T3 to which wheels T2 are attached and a loading platform T1 mounted on the truck body T3. Figures 1(a) and 1(b) are schematic side and rear views of the truck T, respectively.

[0019] The bed T1 of the truck T is rotatably attached to an underframe T4 provided around the floor T6 of the cargo compartment via truck hinges T5 (see FIG. 2 ). The bed T1 includes gates A (specifically, a pair of gates A on each side, for a total of four gates A) that openably cover the lower left and right sides of the cargo compartment, and wings W that openably cover the space above the cargo compartment. To maintain each gate A in an upright, closed state (A1), pillars (not shown) are provided at the middle and end portions of the left and right sides of the underframe T4. In this embodiment, side gates (side gates) that define the sides of the bed T1 are used as the gates A. However, the present embodiment described below can also be applied to a truck T equipped with a rear gate that defines the rear of the bed T1. The gates are sometimes referred to as gates (side gates, back gates). The number of gates A is determined appropriately depending on the size and type of the truck T and is not limited to the example of this embodiment.

[0020] Various parts and mechanisms are disposed below the floor T6 of the luggage compartment and the underframe T4. Therefore, the free space below the floor T6 of the luggage compartment and the underframe T4 is quite narrow, and the gate opening / closing device X of this embodiment is disposed in this narrow space. FIG. 2 schematically shows the gate opening / closing device X and its peripheral devices (hardware), including a power supply that drives the gate opening / closing device X. Regarding the overall appearance of the gate opening / closing device X, FIGS. 3(a) and 3(b) show perspective views of the gate A in an intermediate state between the closed state (A1) and the open state (A2), right side and left side views, FIGS. 4(a) and 4(b) show front and rear views, and FIGS. 6(a) and 6(b) show plan and bottom views, respectively (the state viewed from the side of the loading platform T1 is the front). Since the actual size of the gate A is much larger than the gate opening / closing device X, a small model of the gate A is shown in place of the actual gate A in each of the drawings except for FIG.

[0021] In this embodiment, the number of gate opening / closing devices X corresponding to the number of gates A to be arranged (four in this embodiment) are provided on the floor T6 of the luggage compartment and in the open space below the underframe T4, respectively, and each gate A can be automatically opened and closed individually by each gate opening / closing device X. The gate opening / closing device X can automatically perform the opening and closing work of the gates A, which can be a great burden for an operator, and even if the driver of the truck T is an elderly person, a woman, or someone with little strength, the opening and closing work of the gates A can be easily performed.

[0022] As shown in FIGS. 2 and 3 to 6, the gate opening / closing device X employs a link mechanism L supporting the opening and closing movement of the gate A, which includes a bracket B attached to the outward surface Aa of the gate A, a first arm 1 pivotally attached at one end (upper end) to the bracket B, and a second arm 2 that supports the movement of the first arm 1 while sliding inward and outward relative to the loading platform T1 in the space below the loading platform T4. The gate opening / closing device X also includes mechanical components such as a drive unit 3 that drives the sliding movement of the second arm 2 and an auxiliary drive unit 4 that assists the power of the drive unit 3. Most of the mechanical components are attached via a frame unit F (in this embodiment, the frame unit F includes a cover that hides the mechanical components of the gate opening / closing device X from the outside) provided on the underside of the loading platform T1. Note that in FIG. 2, the portions of the gate opening / closing device X that are hidden by the floor T6 of the luggage compartment and the underframe T4 when viewed from the right side are shown partially in perspective.

[0023] In the link mechanism L, the bracket B is fixed to the tilt A at a position higher than the track hinge T5, which serves as the tilt rotation axis of the tilt A in the closed state (A1), and when the tilt A opens and closes around the track hinge T5, the bracket B moves while rotating integrally with the tilt A around the bracket hinge axis B1, which serves as the pivot point with the first arm 1.

[0024] As shown in FIGS. 2, 3 to 6, 7, and 8, the first arm 1 has an upper end pivotally connected to a bracket hinge shaft B1 and a lower end pivotally connected to the second arm 2 at a position lower than the track hinge T5. In this embodiment, the first arm 1 is configured as a rectangular plate-like body having a rectangular plate-like main body 14 surrounded at the left and right ends by pillar portions 11 and at the top and bottom ends by crosspiece portions 12, 13. The bracket hinge shaft B1 is inserted through a through hole 12a formed in the upper crosspiece portion 12, and a pivot shaft R1, which serves as a pivot point with the second arm 2, is inserted through a through hole (not shown) formed in the lower crosspiece portion 13. In this embodiment, the bracket hinge shaft B1, which is the pivot point of the first arm 1 relative to the bracket B, is set at a predetermined height position on the outward surface Aa of the tilt A in the closed state (A1). The "outward surface Aa of the swing arm A in the closed state (A1)" refers to the surface opposite to the surface (inward surface Ab) of the swing arm A in the closed state (A1) that faces the luggage compartment. The "vertical direction" in the description of the first arm 1, etc., refers to the direction that coincides with the vertical direction when the swing arm A is in the closed state (A1), which is an upright position at +90 degrees as shown in Figure 2.

[0025] As shown in Figures 2, 3 to 6, 7 and 8, the second arm 2 is disposed in a space below the underframe T4 provided around the floor T6 of the luggage compartment, and supports the first arm 1 while being pushed and pulled by the drive unit 3 to slide. In this embodiment, the second arm 2 has a boat-like shape and is made up of a pair of left and right upright walls 21 supported at their outer ends by the left and right first arms 1 and pivot shafts R1, a bottom wall 22 connecting the upright walls 21, and a connecting arm 23 erected on the rear end of the bottom wall 22 and connected to an electric actuator 31 that constitutes the drive unit 3. The connecting arm 23 is supported by the inner ends of the upright walls 21 at slide shafts R2.

[0026] As shown in FIGS. 2, 3 to 6, 9, and 10, the drive unit 3 is mainly composed of an electric actuator 31 arranged substantially symmetrically with respect to the link mechanism L when the gate opening / closing device X is viewed from the front (see FIG. 5(a)). The electric actuator 31 is a typical one having a ball screw-type shaft 32 that moves precisely back and forth within a cylinder. As shown in FIG. 10, the shaft 32 is pivotally attached to a fixed pin R3 (corresponding to the "pin" in this invention) with the inner end of the connecting arm 23 of the second arm 2 inserted into a slit 32a formed at the tip of the shaft 32. As for the entire device, the inner end of the electric actuator 31 is pivotally attached to the frame unit F via a tilting shaft (not shown), and the tip side of the shaft 32 tilts up and down around this tilting shaft, rotating within a narrow angular range. The second arm 2 is configured to slide as the shaft 32 moves back and forth relative to the cylinder. A removable snap pin 33 is fastened by elastic engagement to a through hole formed at the tip of the fixing pin R3 as a retaining member for the fixing pin R3, and in the event of a malfunction or an inability to receive power to the electric actuator 31, the fixing pin R3 can be manually removed by manually unscrewing the snap pin 33, thereby constituting an electric / manual switch K that can manually disconnect the shaft 32 from the connecting arm 23. As will be described later, by removing the snap pin 33 and pulling out the fixing pin R3 in this electric / manual switch K, the link mechanism L can be manually operated to open or close the tilt A. Note that the snap pin 33 can be any suitable pin, such as a cotter pin or a split pin.

[0027] As shown in Figures 2, 3 to 6, and 9, a pair of slide guides 5 are fixed to the frame portion F as members for guiding the sliding movement of the second arm 2. The slide guide 5 is a plate-like member with guide grooves 51 formed therein that are gently curved and convex upward, and both ends of the slide shaft R2 are inserted into the pair of guide grooves 51. With this configuration, when the second arm 2 is driven by the electric actuator 31 and operates, the slide shaft R2 moves inward or outward of the platform T1 (generally in the width direction W of the platform T1, accompanied by a component in the height direction H) while tracing a curved shape within the opening range of the guide grooves 51, and the sliding movement of the second arm is restricted within this movement range.

[0028] The auxiliary drive unit 4 uses the elastic force of a spring to assist the drive force of the electric actuator 31 that constitutes the drive unit 3, and as shown in Figures 2, 3 to 6, 9 and 11, is mainly composed of a spring unit 41 that is arranged approximately symmetrically with respect to the link mechanism L when the gate opening / closing device X is viewed from the front (see Figure 5(a)). The spring unit 41 has a washer 44 that is slidably provided at the deepest part of a case 42 that is a pair of left and right cylindrical bodies connected to each other by a connecting plate 47, and a spring shaft 45 through which a compression coil spring 43, washer 44, spring guide 46, etc. are inserted and whose inner end is fixed with a nut or the like. The spring shaft 45 has a first spring shaft 45a and a second spring shaft 45b inserted into the inner diameter of the compression coil spring 43, pivotally connected by a pin 45c. When the first spring shaft 45a is substantially entirely housed within the case 42, excluding the outer end, it is linear. However, when the entire first spring shaft 45a is exposed outward from the case 42, the first spring shaft 45a rotates around the pin 45c and tilts forward, making the entire spring shaft 45 flexible. The inner end of the second spring shaft 45b is inserted into a cylindrical resin spring guide 46, allowing the compression coil spring 43 to expand and contract smoothly. The spring unit 41 is slidable in the longitudinal direction of a slide support member 48 fixed to the frame F. The slide support member 48 has multiple slide grooves 48a formed in the longitudinal direction, allowing the spring unit 41 to slide. The outer end of each first spring shaft 45a is pivotally connected to a fourth arm, which will be described next, via a pivot shaft R6.

[0029] Meanwhile, in the link mechanism L, as shown in FIGS. 2, 3 to 6, 7, and 8, the lower ends of a pair of plate-like third arms 6 having a partial arc shape and arranged to sandwich the connecting arm 23 are pivotally connected by a pivot shaft R4 to the longitudinal center of both upright walls 21 of the second arm 2. The upper ends of each third arm 6 are pivotally connected by a pivot shaft R5 to the intermediate apexes of a pair of plate-like fourth arms 7 having a V-shape (boomerang shape) and arranged outside each third arm 6. The upper apex of each fourth arm 7 is pivotally connected by a pivot shaft R6 to the outer ends of the first spring shafts 45a of the spring unit 41. The lower apex of each fourth arm 7 is pivotally connected to the frame part F by a rotation shaft R7. This rotation shaft R7 functions as a reference axis for the rotational movement of the first arm 1, second arm 2, third arm 6, and fourth arm 7 that supports the opening and closing movement of the tilt A. In this way, in the gate opening / closing device X of this embodiment, the link mechanism L is configured to be approximately symmetrical on both the left and right sides, so that part of the load of the electric actuator 31 and the spring unit 41 can be distributed and received by the link mechanism L in a state where the link mechanism L is supported on both the left and right sides, thereby reducing the rigidity of each component.

[0030] Here, when opening or closing the gate A, the arms supporting it need to be fixed in the extended position, and after the gate A is set to the closed state (A1), the arms need to be released and set to the stored position (L1) so that they do not protrude outward from the loading platform T1. To achieve this, the locking mechanism 8 provided in the gate opening / closing device X of this embodiment has, as shown in Figures 2 and 12 (Figure 12 shows a state in which the member corresponding to the cover of the frame part F and the slide guide 5 have been removed), a first locking member 81 that restrains the second arm 2 so that it cannot slide when it is in the extended position outward from the loading platform T1, and a second locking member 82 that restrains the first locking member 81 in the state in which it restrains the second arm 2, and further has a first release member 83 that releases the restraint of the second arm 2 by the first locking member 81 and a second release member 84 that releases the restraint of the first locking member 81 by the second locking member 82.

[0031] Specifically, the first locking member 81 is a pair of left and right plate-like members whose base ends are pivotally supported on both ends of a rotation axis R7 that pivotally supports the lower apex of the fourth arm 7. The downward surface 81a at the tip end of the first locking member 81 is curved according to the curved shape of the inner end 21a of the upright wall 21 of the second arm 2 about the slide axis R2, so that the downward surface 81a engages with the inner end 21a of the second arm 2 in the deployed posture (L2) from above to restrain it. The second locking member 82 is a pair of left and right plate-like members pivotally mounted on a pendulum axis R8 near the outer end of the frame portion F and hangs down due to its own weight and spring force. A rollable roller 82a is provided at the lower end of the second locking member 82, and the roller 82a is brought into contact with the upward surface 81b at the tip end of the first locking member 81 to press and restrain the first locking member 81 from above. The first release member 83 is composed of a general solenoid actuator, and the second release member 84 is composed of a general solenoid actuator 84a and a spring 84b. As shown in FIGS. 12 and 14, the first release member 83 is attached to the frame F corresponding to one side of the first locking member 81. When energized, the plunger protrudes and presses horizontally (sideways) against a push plate 81c attached to the inner end of the first locking member 81, causing the first locking member 81 to rotate about a rotation axis R7. The second release member 84 is attached to the frame F corresponding to one side of the second locking member 82 (the same side as the first release member 83). When energized, the plunger protrudes and presses horizontally (sideways) against the upper end of the second locking member 82, causing the second locking member 82 to rotate in a pendulum motion about a pendulum axis R8.

[0032] Next, the operation of the gate opening / closing device X and the opening / closing operation of the gate A will be described. First, when the vehicle T is in a state where it can travel, the gate A is in a closed state (A1) shown in Figures 2 and 14, and the link mechanism L is in a storage position (L1) where the first arm 1, the second arm 2, the third arm 6, and the fourth arm 7 are folded relative to one another. At this time, the locking mechanism 8 is in a released state, the first locking member 81 is inclined around the rotation axis R7 so ​​that the tip end side moves upward, and the second locking member 82 is in a position where it has rotated around the pendulum axis R8 with the roller 82a at its lower end in contact with the upward surface 81b of the first locking member 81. In particular, when the link mechanism L is in the stored position (L1), the first arm 1 is in a substantially vertical position along the outward surface Aa of the upright gate A, and in this state, the outer surface 1a of the first arm 1, which is positioned most outward in the link mechanism L, is closer to the bed T1 (underframe T4 and floor T6) than the top, which is the outermost end of the truck hinge T5. Therefore, when the link mechanism L is in the stored position (L1), there are no parts in the gate opening / closing device X that protrude outward from the bed T1, and the vehicle T meets the conditions for being able to travel on public roads. In addition, the second arm 2 and the first arm 1 are directly connected by the pivot shaft R1, and the first arm 1 is directly connected to the gate A by the bracket hinge shaft B1. Furthermore, the second arm 2 and the third arm 6 are directly connected by a pivot axis R4, the third arm 6 and the fourth arm 7 are directly connected by a pivot axis R5, and the fourth arm 7 is directly connected to the first spring shaft 45a of each spring shaft 45 of the spring unit 41 and the frame portion F by a pivot axis R6 and a rotation axis R7, respectively. When the link mechanism L is in the stored position (L1), the electric actuator 31 pulls the second arm 2 inward into the loading platform T1 to keep it immobile, so in the stored position (L1), the first arm 1, the second arm 2, the third arm 6 and the fourth arm 7 are fixed and maintained in a stable state without rattle even when the vehicle T shakes while traveling.

[0033] When the vehicle T is stopped and the gate A, which is in the closed state (A1), is changed to the open state (A2, see FIGS. 1 and 16), or conversely, when the gate A, which is in the open state (A2), is changed to the closed state (A1), the electric actuator 31 of the drive unit 3 is driven based on an appropriate command. Specifically, when a higher-level controller (control unit C) receives a drive command (such as a command to "open the gate" or "close the gate," which is synonymous with the opening / closing command shown in FIG. 2) based on an input operation by an operator (such as a truck driver) to an input device such as an appropriate button, switch, or touch panel, the control unit C controls the drive of the electric actuator 31 of the drive unit 3 based on the angle of the gate A, thereby automatically opening or closing the gate A.

[0034] When the tilt A is in the closed state (A1), which is an upright position at +90 degrees as shown in FIGS. 2 and 13 , and the link mechanism L is in the retracted position (L1), driving the electric actuator 31 to extend the shaft 32 toward the outer side W of the loading platform T1 causes the second arm 2, to which the connecting arm 23 is pivotally attached at the tip of the shaft 32, to rotate about the fixed pin R3 and begin to slide outwardly of the loading platform T1 while the slide axis R2 is guided by the slide guide 5, as shown in FIG. 14 . At this time, the slide axis R2 slides slightly downward along the slide groove 51, and simultaneously, the fixed pin R3 side of the electric actuator 31 tilts. At this time, the second locking member 82 rotates about the pendulum axis R8 in a direction returning to the vertical position due to its own weight and spring force. The roller 82a at the lower end presses against the upward surface 81b of the first locking member 81, and the first locking member 81 rotates about the rotation axis R7.

[0035] 9 and 12, the downward surface 81a of the first locking member 81 engages with the inner end 21a of the second arm 2 from above, restricting the sliding movement of the second arm 2, and at the same time, the second locking member 82 assumes a vertical position, and the roller 82a presses the upward surface 81b of the first locking member 81, restricting the movement of the first locking member 81. In this state, the locking mechanism 8 locks the sliding movement of the second arm 2 in the extended position (L2) of the link mechanism L, and the subsequent opening operation of the tilt A becomes possible.

[0036] Specifically, when the sliding movement of the second arm 2 is restricted by the locking mechanism 8, the following movements are permitted: extension or retraction of the shaft 32 of the electric actuator 31; rotation of the second arm 2 about the fixed pin R3 relative to the shaft 32; tilting of the electric actuator 31 about the tilting axis relative to the frame part F; rotation of the second arm 2 about the slide axis R2 relative to the slide guide 5 and the frame part F; rotation of the first arm 1 about the pivot axis R1 relative to the second arm 2; and rotation of the third arm 6 about the pivot axis R4. The pivotal movement of the fourth arm 7 relative to the second arm 2 about the pivot axis R5 of the fourth arm 7, the pivotal movement of the spring unit 41 relative to the first spring axis 45a about the pivot axis R6 of the fourth arm 7, the expansion and contraction movement of the compression coil spring 43 as the spring axis 45 is pushed and pulled by the fourth arm 7, and the sliding movement of the spring unit 41 relative to the slide support member 48 of the case 42 all function to enable the pivotal movement of the tilt A relative to the first arm 1 about the bracket hinge axis B1, i.e., the opening and closing movement.

[0037] 9 and 12, the tilt A can be opened to a fully open state (A3) shown in Fig. 16 via a half-open state (A2) shown in Fig. 15. In this process, in the spring unit 41 that has slid outward along the slide groove 48a, the first spring shaft 45a, which has advanced with the rotation of the fourth arm 7, becomes exposed from the case 42 up to the connection point with the second spring shaft 45b, and the first spring shaft 45a rotates and tilts forward around the pin 45c. When closing the tilt A, the procedure is reversed by driving the electric actuator 31 from the fully open state (A3) of the tilt A shown in Figure 16 to retract the shaft 32, which then passes through the half-open state (A2) shown in Figure 15 and into the closed state (A1) shown in Figure 12, causing the link mechanism L to assume the deployed position (L2) shown in Figures 9 and 12.

[0038] In this way, the drive torque (drive force) required to rotate the link mechanism L by the thrust of the electric actuator 31 of the drive unit 3 between the closed state (A1) and the fully open state (A3) of the tilt-tilt A via the deployed posture (L2) of the link mechanism L is the difference between the torque based on the weight of the tilt-tilt A and the torque based on the auxiliary force (elastic force) of the compression coil spring 43 in the auxiliary drive unit 4. In other words, when changing the tilt-tilt A from the closed state (A1) to the fully open state (A3), the thrust of the electric actuator 31 is applied in a state in which the elastic force of the compression coil spring 43 acts against the force of the tilt-tilt A trying to open due to its own weight, and the tilt-tilt A slowly moves toward the fully open state (A3). On the other hand, when the gate A is changed from the fully open state (A3) to the closed state (A1), the force of the gate A trying to open due to its own weight is countered by the elastic force of the compression coil spring 43. By applying the thrust of the electric actuator 31, the gate A slowly moves toward the closed state (A1). Therefore, in the gate opening / closing device X of this embodiment, the auxiliary drive unit 4 is provided, thereby improving the efficiency (power saving) of the drive unit 3. FIG. 17 shows the results of an analysis of the torque due to the thrust of the electric actuator 31 required to open and close the gate A, based on the difference between the torque due to the gate A's own weight and the torque due to the auxiliary force of the compression coil spring 43 in the auxiliary drive unit 4. In this figure, the vertical axis represents the torque due to the thrust of the electric actuator 31 (unit: N m), and the horizontal axis represents the angle of the gate A (the closed state (A1) is set to 0°). Here, 0 deg is the closed state (A1), -180 deg is the fully open state (A3), the α line shows the change in torque when the tilt is opened (from the closed state (A1) to the fully open state (A3)), and the β line shows the change in torque when the tilt is closed (from the fully open state (A3) to the closed state (A1)). Also, when the torque passes the horizontal axis of 0 N·m, there is a turning point of force (the point where the relationship between the torque based on the weight of the tilt A and the torque due to the auxiliary force of the compression coil spring 43 in the auxiliary drive unit 4 reverses), and if this turning point is passed multiple times during the opening and closing operation of the tilt A, the operation of the link mechanism L will become unstable, so it is best to avoid passing through the turning point as much as possible.However, there may be multiple turning points depending on the relationship between the torque due to the weight of the tilt A, the torque due to the auxiliary force of the compression coil spring 43 in the auxiliary drive unit 4, and the link mechanism. In the tilt opening / closing device X of this embodiment, as shown in the figure, the force turning point is passed only once each during the opening and closing operation of the tilt A, thereby realizing extremely smooth opening and closing operation of the tilt A.

[0039] Next, with the gate A in the fully open state (A3), cargo can be loaded and unloaded from the loading platform T1. After the loading and unloading operation is completed, the gate A is switched from the fully open state (A3) to the closed state (A1). As described above, this switching process involves driving the electric actuator 31 to retract the shaft 32 from the fully open state (A3) of the gate A shown in FIG. 16, thereby returning the gate A to the half-open state (A2) shown in FIG. 15 and then to the closed state (A1) shown in FIG. 12, thereby returning the link mechanism L to the deployed position (L2) shown in FIGS. 9 and 12. From this state, the lock state of the link mechanism L by the lock mechanism 8 is released, thereby bringing the link mechanism L to the stowed position (L1). Specifically, in the deployed position (L2) shown in FIGS. 9 and 12, the solenoid actuator of the second release member 84 is energized to protrude the plunger, which presses the upper end of the second lock member 82, thereby starting to rotate the second lock member 82 about the pendulum axis R8. At approximately the same time, the solenoid actuator of the first release member 83 is energized to project the plunger and press the push plate 81c of the first locking member 81, causing the first locking member 81 to begin rotating about the rotation axis R7. At this time, the roller 82a of the second locking member 82 rolls on the upward surface 81b at the tip of the first locking member 81, and at the same time, the second arm 2 including the slide axis R2 slides and rotates inward along the guide groove 51 of the slide guide 5, and the link mechanism L passes through the state shown in FIG. 14 and assumes the stored position (L1) shown in FIGS. 2 and 13. During this process of storing the link mechanism L, the electric actuator 31 performs a tilting operation about the tilting axis while retracting the shaft 32 in accordance with the operation of the second arm 2. Furthermore, as the spring unit 41 rotates about the pivot shaft R6 of the fourth arm 7 relative to the spring shaft 45, the spring shaft 45 slides the spring unit 41 toward the inside of the loading platform T1. As a result, the gate opening / closing device X of this embodiment, with the link mechanism L in the stored position (L1), is stored compactly in the space below the loading platform T1, and the vehicle T is again ready to travel.

[0040] In the gate opening / closing device X of this embodiment described above, when the electric actuator 31 in the drive unit 3 is operating normally, the drive force of the electric actuator 31 is assisted by the auxiliary drive unit 4, and the gate A can be automatically opened and closed while reducing the power consumption of the electric actuator 31. However, if the electric actuator 31 breaks down or is not energized, the opening and closing operation of the gate A must be switched to manual. In preparation for such an event, this embodiment is provided with an electric / manual switch K, which manually removes the snap pin 32 from the fixing pin R3 and pulls out the fixing pin R3 from the connecting arm 23 of the second arm 2 and the shaft 32 of the electric actuator 31, thereby severing the connection between the link mechanism L and the drive unit 3. Even in this state, the fourth arm 7 remains pivotally attached to the outer ends of the rods 45 of the spring unit 41 by the pivot shafts R6, so when manually opening or closing the tilt A, the elastic force of the compression coil springs 43 in each spring unit 41 of the auxiliary drive unit 4 acts as an assist via the link mechanism L, reducing the force load on the person lifting or supporting the tilt A. In particular, if it becomes necessary to switch from electric to manual operation when the tilt A is in the fully open state (A3), the task of manually lifting the heavy tilt A and closing it (A1) requires a great deal of effort, but the assistance of the auxiliary drive unit 4 greatly reduces the burden on the person in closing the tilt A.

[0041] In addition, in this embodiment, the electric / manual switching unit K is configured so that the link mechanism L and the electric actuator 31 are pivotally connected by a fixing pin R3 that can be manually inserted and removed, so that the opening and closing operation of the tilt A can be easily switched between electric and manual.

[0042] Furthermore, a snap pin 33 is used as a retaining member that can be manually attached and detached by elastic engagement with the fixing pin R3, and the fixing pin R3 can be easily inserted and removed by manually attaching and detaching the snap pin 33. With this configuration, if the link mechanism L and the electric actuator 31 are connected by the fixing pin R3, the opening and closing operation of the tilt A by the electric actuator 31 can be performed safely by attaching the snap pin 33 to the fixing pin R3.

[0043] In addition, the auxiliary drive unit 4 is equipped with a spring unit 41, which is an elastic member that imparts elastic force to the link mechanism, and appropriately realizes a mechanical auxiliary drive unit 4 that assists the drive force of the drive unit 3 to the link mechanism L when operated electrically, and assists in opening and closing the tilt A manually when operated manually.

[0044] Although one embodiment of the present invention has been described above, the present invention is not limited to the configuration of the above embodiment. For example, the specific shapes, configurations, and locations of the components constituting the link mechanism L, lock mechanism 8, drive unit 3, auxiliary drive unit 4, and electric / manual switch unit K can be changed as appropriate depending on the size of the vehicle T and the gate A, the size of the space below the loading platform T1 that accommodates the gate opening / closing device X, etc.

[0045] The drive unit 3 is not limited to the electric actuator 31 described above, and any suitable actuator can be used as long as it is configured to electrically drive the link mechanism L, such as one configured to slide the second arm 2 using an electric motor. The auxiliary drive unit 4 is also not limited to the spring unit 41 described above, and is not particularly limited to any particular configuration as long as it connects an appropriate elastic member to the link mechanism L to assist the opening and closing operation of the tilt with a mechanical driving force via the link mechanism L, both in electric and manual modes. Furthermore, the electric / manual switching unit K can be configured, for example, to connect the electric actuator 31 and the link mechanism L with a member such as a latch (a structure that can be switched using a latch mechanism, ratchet mechanism, etc.), and to switch to electric mode when the latch is engaged and manual mode when the latch is released. The electric / manual switching unit K is not limited to the fixing pin R3 or the snap pin 33, and various configurations can be used as long as they can be manually attached and detached.

[0046] The cargo vehicles in which the gate opening / closing device L of the present invention can be installed are not limited to trucks (classified according to load capacity as small trucks (2-ton and 3-ton trucks), medium-sized trucks (4-ton trucks), large trucks (10-ton trucks), and light trucks), but can also be installed in cargo vehicles T such as trailers and dump trucks.

[0047] Furthermore, the specific configuration of each part is not limited to the above embodiment, and various modifications are possible within the scope of the present invention. [Explanation of symbols]

[0048] 3...Drive unit 31...Electric actuator 33...Prevention member (snap pin) 4...Auxiliary drive unit 43...Elastic member (compression coil spring) A…Tilt K...Electric / Manual Switching Unit L...Link mechanism R3...Pin (fixing pin) T... freight vehicle (truck) T1...cargo bed X...Tilt opening / closing device

Claims

1. A gate opening / closing device that automatically opens and closes a gate provided on the loading platform of a vehicle such as a freight vehicle, The vehicle has a link mechanism that supports the opening and closing operation of the gate, a drive unit that has an electric actuator that drives the link mechanism in the space below the loading platform, and a mechanical auxiliary drive unit that assists the drive force of the drive unit, A gate opening / closing device characterized in that the link mechanism is individually connected to the electric actuator and the auxiliary drive unit, and is equipped with an electric / manual switching unit that switches the driving force for the link mechanism by selectively connecting or disconnecting the connection points between the link mechanism and the electric actuator.

2. 2. The gate opening / closing device according to claim 1, wherein the electric / manual switching unit is configured such that the link mechanism and the electric actuator are pivotally connected by a manually insertable and removable pin.

3. 3. The gate opening / closing device according to claim 2, further comprising a retaining member that can be manually attached and detached by elastic engagement with the pin.

4. 4. The gate opening / closing device according to claim 1, wherein the auxiliary drive unit includes an elastic member that applies an elastic force to the link mechanism.

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