Gate opening / closing mechanism

Abstract

To provide a gate opening / closing device which downsizes an electric drive part and a spring type auxiliary drive part as drive sources required for opening / closing a gate, and can be designed so as to be settled in a region below a narrow and limited load-carrying platform.SOLUTION: A gate opening / closing device X has an auxiliary drive part 4 for assisting drive force for rotating a link mechanism L for supporting opening / closing operation of a gate A, wherein the auxiliary drive part 4 is structured such that a case 42 is mounted on springs 43 stored in the case 42, spring shafts 45 synchronously protruding from / receding into the case 42 while expanding / contracting the spring 43 by being connected to the link mechanism L, and a rail groove 48a formed on a slide support member 48, and is structured to be guided to the rail groove 48a accompanied by operation of the link mechanism L, synchronizes the case 42 with inner / outer sides of a load-carrying platform T1, and slidably moves the case 42.SELECTED DRAWING: Figure 11

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 if 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 collapse (start to open) 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 spring shaft 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] Such a gate opening / closing device is placed in the space below the loading platform, but since the space below the loading platform is also home to a wide variety of on-board components required for truck operation in addition to the gate opening / closing device, the area allowed for placement of the gate opening / closing device is in fact only a very limited and narrow space.

[0007] Furthermore, for example, the gate opening / closing device disclosed in Patent Document 3 is configured to include an electric actuator that rotates a fixed shaft via a power transmission mechanism (a mechanism consisting of two sprockets or chains installed axially of the fixed shaft or drive motor) using the rotational force of the drive motor to operate a link section that supports the gate opening / closing operation, and an auxiliary power spring mechanism for applying auxiliary power.

[0008] In such a gate opening / closing device, the drive motor and power transmission mechanism are installed side by side in the axial direction of the fixed shaft and drive motor, so the electric actuator and auxiliary power spring mechanism are very bulky, and it requires considerable ingenuity to arrange the gate opening / closing device within the allowable area under the loading platform without interfering with other on-board components. Also, the drive motor and power transmission mechanism in the electric actuator are located on one side of the link in the left-right direction when viewed from the front of the gate, and a configuration is adopted in which power is transmitted to the fixed shaft of the link, and power is transmitted while the drive motor and power transmission mechanism are supported by a cantilever on the link, which makes the configuration of the electric actuator unstable and requires each component to be made larger and more rigid.

[0009] The present invention has been made with an eye on these problems, and aims to provide a gate opening / closing device that can be housed in the extremely limited and narrow space below the loading platform by miniaturizing the power mechanism components for opening and closing the gate, such as the electric actuator and auxiliary power spring, and to realize a configuration that does not require special high rigidity by devising the configuration and arrangement of the power mechanism components. [Means for solving the problem]

[0010] 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.

[0011] The gate opening and closing device of the present invention has a link mechanism that supports the opening and closing operation of the gate, and an auxiliary drive unit that assists the driving force for rotating the link mechanism, and is characterized in that the auxiliary drive unit comprises a case, a spring housed in the case, a spring shaft connected to the link mechanism that protrudes and retracts from the case while expanding and contracting the spring, and a slide support member formed with a rail groove on which the case is placed, and is configured so that the case is guided by the rail groove as the link mechanism operates and slides inward and outward in sync with the movement of the link mechanism.

[0012] In the gate opening / closing device according to the present invention, the elastic force of the spring can apply an auxiliary driving force to the link mechanism in response to the driving force of the auxiliary driving unit that rotates the link mechanism. Furthermore, by miniaturizing the auxiliary driving unit, the installation of the auxiliary driving unit on the loading platform can be simplified. Furthermore, in the gate opening / closing device according to the present invention, the auxiliary driving unit is configured so that a case containing the spring and spring shaft is housed in a rail groove and slides inward and outward below the loading platform along the slide support member. This eliminates the need to move the case vertically, thereby reducing the height of the auxiliary driving unit and keeping its depth within the longitudinal range of the slide support member. This allows the auxiliary driving unit to be miniaturized so as not to interfere with the loading platform or the link mechanism.

[0013] In such a gate opening / closing device of the present invention, if the spring shaft in the auxiliary drive unit is configured so that a first spring shaft pivotally attached to the link mechanism and a second spring shaft housed in the case are pivotally attached to each other, the parts that follow when the link mechanism moves up and down are limited to the first spring shaft, preventing the case from moving up and down, and the function of expanding and contracting the spring as a whole can be ensured.

[0014] Furthermore, if the auxiliary drive unit is configured to include a pair of mutually connected cases arranged side by side, a pair of springs housed in each case, a pair of spring shafts that synchronously protrude and retract from each case as the springs expand and contract, and a slide support member on which each case is placed and on which a pair of the rail grooves are formed, the auxiliary drive unit can be arranged with balance, particularly left and right, relative to the link mechanism, and the balance of the sliding movement of the cases supported by the slide support member is also improved. Also, with regard to the springs, while the auxiliary power spring mechanism in the gate opening / closing device of Patent Document 3 essentially used a single relatively large and powerful spring, in the present invention, by using a pair of springs, each spring can be made smaller while still allowing the two relatively small springs to exert a strong elastic force as a result of their combined force, and furthermore, the cases that house each spring can be made smaller, so that the configuration can easily achieve a smaller auxiliary drive unit and reduced rigidity.

[0015] Furthermore, the gate opening / closing device of the present invention has a drive unit equipped with an electric actuator that drives the link mechanism in the space below the loading platform. By arranging this electric actuator along the center of the link mechanism in the width direction and connecting it to the link mechanism, the main driving force for the link mechanism can be provided by the drive unit equipped with the electric actuator. Furthermore, the drive unit is balanced left and right with respect to the link mechanism, eliminating a cantilever structure. This eliminates interference with the operation of the link mechanism or other on-board components, making it easy to design a gate opening / closing device with a drive unit that is easily miniaturized. The miniaturization of the drive unit reduces the rigidity of the drive unit's components and simplifies the installation of an auxiliary drive unit to the loading platform. Furthermore, the miniaturization of the drive unit also simplifies the installation of an auxiliary drive unit to the loading platform.

[0016] Furthermore, by pivotally attaching the electric actuator to the link mechanism and configuring the electric actuator to be pivotally attached inside the loading platform, the attachment point of the electric actuator to the loading platform can be fixed, and as long as there is sufficient space, such as a configuration in which no other vehicle components are mounted below the electric actuator, the electric actuator can be tilted in response to the up and down movement of the link mechanism, thereby maintaining the necessary operation of the link mechanism. [Effects of the Invention]

[0017] According to the present invention, it is possible to easily achieve miniaturization while arranging the drive unit and auxiliary drive unit for driving the opening and closing operation of the gate in a balanced manner relative to the link mechanism, thereby making it possible to provide a gate opening and closing device that reduces the rigidity of the drive unit and auxiliary drive unit while arranging them in a limited area below the cargo bed and does not interfere with the link mechanism or other on-board equipment. [Brief explanation of the drawings]

[0018] [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

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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 FIG. 2.

[0027] 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.

[0028] 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 has a slit 32a formed at its tip, and the inner end of the connecting arm 23 of the second arm 2 is inserted into the slit 32a, which is formed at the tip of the shaft 32, and is pivotally attached to a fixed pin R3. As for the entire device, the inner end of the electric actuator 31 is pivotally attached to the frame 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 slides 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] In the gate opening / closing device X of this embodiment described above, the drive unit 3 and the auxiliary drive unit 4 are arranged in a balanced manner along the center of the width direction of the link mechanism L, thereby reducing the rigidity of the components and appropriately applying a drive force and an auxiliary drive force to the link mechanism L for opening and closing the gate A. In particular, in this embodiment, a pair of compression coil springs 43 is used in the auxiliary drive unit 4. This allows the required auxiliary drive force to be obtained with each smaller compression coil spring 43 than when a single large, powerful spring is used as the auxiliary drive force. Moreover, by using the spring unit 41 formed by the case 42 that houses each compression coil spring 43, the entire auxiliary drive unit 4 can be made smaller, making it easier to fit into the limited area allowed for the gate opening / closing device X in the space below the loading platform 4, and facilitating the installation of the auxiliary drive unit.

[0043] Furthermore, in the gate opening / closing device X of this embodiment, the spring unit 41 in the auxiliary drive unit 4 is configured to slide inward and outward below the loading platform T1 along the slide support member 48 by the rail groove 48a, so that, particularly in the process of the link mechanism L reaching the stored posture (L1) or the deployed posture (L2), the rotational movement of the fourth arm 7 about the rotation axis R7 and the sliding movement of the spring unit 41 are performed in parallel, thereby suppressing interference of the case 42 with the loading platform T1 and interference of the second spring axis 45b with the link mechanism L caused by the expansion and contraction movement of the compression coil spring 43 when the spring axis 45 is pushed and pulled by the fourth arm 7. Therefore, the size of the auxiliary drive unit 4 can be kept within a predetermined range in the height direction based on the dimensions of the spring unit 41 and in the depth direction based on the dimensions of the slide support member 48, thereby realizing a compact auxiliary drive unit 4.

[0044] Furthermore, the spring shaft 45 is configured such that the first spring shaft 45a, which is pivotally attached to the pivot shaft R6 on the fourth arm 7 of the link mechanism L, and the second spring shaft 45b, which is housed in the case 42, are pivotally attached via a pin 45c. Therefore, the first spring shaft 45a is the only part that tilts forward in response to the rotation of the link mechanism L, preventing the case 42 from moving up and down, while the compression coil spring 43 can be expanded and contracted by the spring shaft 45 as a whole.

[0045] Furthermore, by configuring the shaft 32 of the electric actuator 3 to be pivotally connected to the connection arm 23 of the link mechanism L by a fixed axis R3, and also pivotally connected to the frame part F at the inner end of the electric actuator 3 via a tilting axis, it is possible to fix the attachment point of the electric actuator 3 to the platform T1, while tilting the electric actuator 3 in response to the rotational movement of the link mechanism L, thereby maintaining the necessary operation of the link mechanism L. This makes it possible to reduce the size of the electric actuator 3 (particularly in the height direction).

[0046] 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.

[0047] The drive unit 3 is not limited to the electric actuator 31 described above, but any suitable actuator can be used as long as it is configured to electrically drive the link mechanism L, such as an actuator configured to slide the second arm 2 by driving an electric motor. The auxiliary drive unit 4 is also not limited to the spring unit 41 using the compression coil spring 43 or spring shaft described above, but can be configured to use a spring unit 41 equipped with a spring or spring shaft of an appropriate configuration, and to have a slide support member provided accordingly.

[0048] In addition, in the above-described embodiment, an example was shown in which the auxiliary drive unit 4 has a pair of case 42, spring 43, spring shaft 45, and rail groove 48a of slide support member 48, but the number of each of these parts is not limited to two, and a configuration with only one of each, or a configuration with a set of three or more, can also be adopted.

[0049] 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.

[0050] 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]

[0051] 3...Drive unit 31...Electric actuator 4...Auxiliary drive unit 41...Spring unit 42…Case 43...Spring (compression coil spring) 45...Spring shaft 45a...First spring shaft 45b...Second spring shaft 48...Slide support member 48a...Rail groove A…Tilt L...Link mechanism 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 camera includes a link mechanism that supports the opening and closing operation of the tilt mechanism, and an auxiliary drive unit that assists in the drive force for rotating the link mechanism, A gate opening and closing device characterized in that the auxiliary drive unit comprises a case, a spring housed in the case, a spring shaft connected to the link mechanism that protrudes and retracts from the case while expanding and contracting the spring, and a slide support member formed with a rail groove on which the case is placed, and is configured so that the case is guided along the rail groove as the link mechanism operates, causing it to slide inward and outward in synchronous with the movement of the link mechanism.

2. 2. The gate opening / closing device according to claim 1, wherein the auxiliary drive unit includes a first spring shaft pivotally connected to the link mechanism and a second spring shaft housed in the case, the first spring shaft and the second spring shaft being pivotally connected to each other.

3. The gate opening and closing device according to claim 2, wherein the auxiliary drive unit comprises a pair of the cases arranged side by side and connected to each other, a pair of the springs housed in each of the cases, a pair of the spring shafts that protrude and retract synchronously from each of the cases while expanding and contracting each of the springs, and the slide support member having a pair of the rail grooves on which each of the cases is placed.

4. A gate opening / closing device as described in any one of claims 1 to 3, which has a drive unit equipped with an electric actuator that drives the link mechanism in the space below the loading platform, and the electric actuator is provided along the widthwise center of the link mechanism and connected to the link mechanism.

5. 5. The gate opening / closing device according to claim 4, wherein the electric actuator is pivotally mounted to the link mechanism and is pivotally mounted inside the loading platform.

Images