Tailgate opening and closing mechanism

Abstract

To provide an automatic gate opening / closing mechanism that does not invite an increase in a size but enables a gate to smoothly move at a time of automatic opening or closing.SOLUTION: A gate opening / closing mechanism includes a link part 3 capable of changing postures between a thrust posture (3T) of thrusting a lower end of a first arm 1 to outside of an outward facing surface A3 of a gate A, and a storage posture (3S) of positioning the lower end of the first arm 1 to immediately below or substantially immediately below a pivotal point R1 of the first arm 1 with respect to a bracket B, and a thrust posture sustaining part 6 that sustains the link part 3 in the thrust posture (3T). When the gate A is in a closed condition (A1), a second arm 2 is turned about a fixed axle RF1. Thus, the link part 3 is changed from the storage posture (3S) to the thrust posture (3T). After the link part 3 is changed from the storage posture (3S) to the thrust posture (3T), while the thrust posture (3T) is sustained by the thrust posture sustaining part 6, the gate A is changed from the closed condition (A1) to an open condition (A2).SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to an awning opening and closing mechanism for opening and closing an awning provided on a loading platform of a freight vehicle such as a truck.

Background Art

[0002] In the transportation industry, which accounts for about 5% of Japan's GDP, the logistics industry, which has a market share of over 60% of the transportation industry, is expanding due to environmental changes and is expected to grow significantly in the future. On the other hand, in the logistics industry, automation of truck loading and unloading operations is required to address the shortage of truck drivers and improve safety.

[0003] Conventionally, the opening and closing operation of the awning has been performed manually by an operator with the assistance of a manual opening and closing assistance device (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, when performing the opening and closing operation of the awning with the assistance of a manual opening and closing assistance device, a certain amount of force is required for the operation of lifting the awning (switching from the open state to the closed state), which places a burden on the operator. Also, even when attempting to realize a mechanism for automatically opening and closing the awning by adding an electric mechanism to a conventional manual opening and closing assistance device, when operating the awning from the closed state to the open state, due to the configuration of the conventional manual opening and closing assistance device, the awning suddenly collapses (starts to open), making it difficult to ensure a smooth opening and closing operation of the awning.

[0006] Furthermore, if there are parts that protrude from the sides of the truck, these protruding parts will define the width of the vehicle. Therefore, if the tailgate opening and closing mechanism is positioned to protrude laterally from the cargo bed, the width of the cargo bed will be reduced by the amount of the protrusion, which in turn will reduce the size of the cargo bed and decrease the load capacity. For this reason, conventional manual tailgate opening and closing assist devices are designed not to protrude from the sides of the truck.

[0007] This invention was made in view of these problems, and its main objective is to provide an automatic tailgate opening and closing mechanism that can automatically open and close the tailgate while maintaining the same size as conventional mechanisms, and in particular prevents and suppresses situations in which the tailgate suddenly starts to open, thereby enhancing safety and enabling smooth and seamless tailgate opening and closing operations. [Means for solving the problem]

[0008] In other words, the present invention relates to a tailgate opening and closing mechanism for automatically opening and closing the tailgates provided on the cargo bed of a cargo vehicle. Examples of cargo vehicles having a cargo bed include trucks, trailers, dump trucks, etc. The tailgates are also called gates, and specific examples include side tailgates that define the sides of the cargo bed and tailgates that define the rear of the cargo bed.

[0009] Furthermore, the tailgate opening and closing mechanism according to the present invention comprises a bracket that supports the tailgate, a first arm whose tip is pivotally attached to the bracket and which stands upright in a direction parallel or substantially parallel to the upright direction of the tailgate when the tailgate is in the closed position, a second arm which rotates around a fixed axis in the space below the cargo bed, a link portion provided between the first arm and the second arm, and a bracing posture maintenance portion that can lock the link portion in a predetermined position, and is particularly characterized in the following respects. In other words, the tailgate opening and closing mechanism according to the present invention comprises a link section that can change its posture between a braced position in which the lower end of the first arm is extended to a position further from the cargo bed than the outward-facing surface of the tailgate, and a retracted position in which the lower end of the first arm is positioned directly below or approximately directly below the pivot point of the first arm relative to the bracket, and a braced position maintenance section that locks the link section in the braced position. The mechanism is configured such that when the tailgate is in the closed position, the link section switches from the retracted position to the braced position by rotating the second arm around a fixed axis, and after the link section switches from the retracted position to the braced position, the braced position maintenance section maintains the braced position while switching the tailgate from the closed state to the open state.

[0010] With the tailgate opening and closing mechanism according to the present invention, by setting the link portion provided between the first arm and the second arm into a braced position, the lower end of the first arm can be moved to a position further from the center in the width direction of the cargo bed than the outward-facing surface of the tailgate. While this braced position is maintained by the braced position maintenance portion, the second arm appears to be extended by the amount of the link portion, and by creating an angle between the tailgate and the first arm, a state in which the tailgate is supported can be ensured, and force can be transmitted to the tailgate. As a result, an automatic tailgate opening and closing mechanism can be realized that switches smoothly from the closed state to the open state without accelerating when the tailgate begins to open.

[0011] In addition, with the tailgate opening and closing mechanism according to the present invention, the link section can be stored when the tailgate is closed and not being opened or closed, thus preventing the first arm and link section from protruding to the side or rear of the cargo bed during normal use that does not involve opening or closing the tailgate. In particular, it is possible to avoid a situation where the width of the cargo bed is reduced by the amount it protrudes laterally beyond the cargo bed, and consequently the size of the cargo bed is reduced and the load capacity decreases.

[0012] A preferred configuration for the braced posture maintenance unit in the present invention includes a configuration with a locking unit that restricts the change of posture of the link unit in the braced position, and a configuration with an unlocking unit that releases the restriction on the operation of the link unit by the locking unit. With a configuration with a locking unit, the link unit can be maintained in the braced position by restricting the operation of the link unit with the locking unit. With a configuration with an unlocking unit, the restriction on the operation of the link unit by the unlocking unit can be released when the tailgate has finished switching from the open state to the closed state, that is, when the tailgate has finished changing to the +90 degree upright position, thereby releasing the braced posture maintenance unit from maintaining the braced position of the link unit. This allows the link unit to be switched from the braced position to the retracted position and stored in a limited predetermined space without protruding beyond the cargo bed. Note that "when the tailgate has finished switching from the open state to the closed state" means the time when the tailgate has switched from the open state to the closed state (+90 degree upright position), and is not synonymous with the time when the operator has completely finished closing the tailgate. In other words, the point at which the operator has completely finished closing the tailgate is at least when the tailgate has switched from the open position to the closed position (upright position at +90 degrees), and further when the link section has been switched from the extended position to the retracted position and the entire link section has been placed in the space below the cargo bed in a form that does not protrude beyond the cargo bed, or at any appropriate point thereafter.

[0013] In particular, in the tilting mechanism according to the present invention, if the link section includes a main link with one end set as a pivot point to a first arm and a pivot point to a second arm at a predetermined distance from this pivot point, a first lock link with the other end set as a pivot point to the main link, and a second lock link with one end set as a pivot point to the first lock link and the other end set as a pivot point to the second arm, and the bracing posture maintenance section includes a lock pin that fits between the first lock link and the second lock link, which are mutually expanded around the pivot points of the lock links (first lock link and second lock link) in the braced position, and the lock pin restricts the movement of the first lock link and the second lock link in the direction in which they fold each other, then the link section and the bracing posture maintenance section can be realized with a relatively simple configuration, which is preferable. Furthermore, if the present invention is an invention that limits the requirements of Claims 2 and 4 to Claim 1 (the invention of Claim 1 + Claim 2 + Claim 4) or an invention that limits the requirements of Claims 2, 3 and 4 to Claim 1 (the invention of Claim 1 + Claim 2 + Claim 3 + Claim 4), then the lock pin functions as a part corresponding to the locking mechanism. [Effects of the Invention]

[0014] According to the present invention, by setting the link portion provided between the first arm and the second arm into a braced position, the first arm can support the closed tailgate in an upright position at a predetermined angle. By maintaining this supported state, a tailgate opening and closing mechanism can be provided that operates smoothly without the tailgate suddenly opening during the movement from the closed state to the open state. [Brief explanation of the drawing]

[0015] [Figure 1] A schematic diagram of a freight vehicle equipped with a tailgate opening and closing mechanism according to one embodiment of the present invention. [Figure 2] A schematic diagram showing the tailgate opening / closing mechanism and its peripheral equipment according to the same embodiment. [Figure 3]A diagram showing the aoili closed state (link part in storage posture) in the same embodiment. [Figure 4] A diagram showing the aoili closed state (link part in stretched posture) in the same embodiment. [Figure 5] A perspective view showing an enlarged partial view of the main part of FIG. 4 with some parts omitted. [Figure 6] A diagram for explaining the stretched posture maintaining part in the same embodiment. [Figure 7] A diagram for explaining the unlocking part in the same embodiment. [Figure 8] A diagram showing the state of the aoili at 0 degrees (link part in stretched posture) in the same embodiment. [Figure 9] A diagram showing the aoili open state (link part in stretched posture) in the same embodiment. [Figure 10] A diagram for explaining the force transmission by the conventional aoili opening / closing mechanism and the behavior at the start of aoili opening. [Figure 11] Explain the force transmission by the aoili opening / closing mechanism according to the present invention. [Figure 12] An enlarged view of the main part corresponding to FIG. 2 showing a modification example of the aoili opening / closing mechanism according to the same embodiment. [Figure 13] An enlarged view of the main part corresponding to FIG. 2 showing a modification example of the aoili opening / closing mechanism according to the same embodiment. [Figure 14] An enlarged view of the main part corresponding to FIG. 2 showing a modification example of the aoili opening / closing mechanism according to the same embodiment. [Figure 15] An enlarged view of the main part corresponding to FIG. 2 showing a modification example of the aoili opening / closing mechanism according to the same embodiment. [Figure 16] An enlarged view of the main part corresponding to FIG. 2 showing a modification example of the aoili opening / closing mechanism according to the same embodiment. [Figure 17] An enlarged view of the main part corresponding to FIG. 2 showing a modification example of the aoili opening / closing mechanism according to the same embodiment. [Figure 18] An enlarged view of the main part corresponding to FIG. 4 showing a modification example of the aoili opening / closing mechanism according to the same embodiment.

Modes for Carrying Out the Invention

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0017] The aori opening and closing mechanism X according to this embodiment enables the automatic opening and closing of the aori A of the cargo bed T1 by being mounted on, for example, the cargo vehicle T (truck) shown in FIG. 1.

[0018] The truck T is a large truck (for example, a 25t truck) including a truck body T3 to which tires T2 are attached and a cargo bed T1 mounted on the truck body T3. FIGS. 1(a) and (b) are respectively schematic side views and rear views of the truck T.

[0019] The cargo bed T1 of the truck T is rotatably attached via hinges T5 (see FIG. 2) to a base frame T4 provided around the floor T6 of the cargo compartment, and includes aori A (specifically, one pair on each of the left and right sides, a total of 4 aori A) that can open and cover the lower parts of the left and right side surfaces of the cargo compartment, and a wing W that can open and cover the upper space of the cargo compartment. In addition, in order to maintain the closed state (A1) in which each aori A stands upright, columns (not shown) are provided at the middle parts and end parts on the left and right of the base frame T4 respectively.

[0020] Various parts and mechanisms are arranged below the floor T6 of the cargo compartment and the base frame T4. Therefore, the empty space below the floor T6 of the cargo compartment and the base frame T4 is quite narrow, and the aori opening and closing mechanism X of this embodiment shown in FIGS. 2 and 3 is arranged in such a narrow space. Here, FIG. 2 schematically shows the aori opening and closing mechanism X and peripheral devices (hardware) including a power source that is a driving source for driving the aori opening and closing mechanism X.

[0021] In this embodiment, a number of tailgate opening / closing mechanisms X corresponding to the number of tailgates A (four in this embodiment) are provided in the empty space below the cargo floor T6 and the underframe T4, respectively, and each tailgate A is set to be individually and automatically opened and closed by each tailgate opening / closing mechanism X. The tailgate opening / closing mechanisms X make it possible to automatically perform the opening and closing of the tailgates A, which can be a great burden for workers, so that even elderly people, women, or other physically weak people can easily open and close the tailgates A while driving the truck T.

[0022] As shown in Figures 2 and 3, the tailgate opening and closing mechanism X comprises a bracket B that supports the tailgate A, a first arm 1 with one end (upper end) pivotally attached to the bracket B, a second arm 2 that rotates around a fixed axis RF1 in the space below the cargo bed T1, and a link section 3 provided between the first arm 1 and the second arm 2. Note that the link section 3 is omitted in Figure 2.

[0023] Bracket B is fixed to the tailgate A at a position higher than the tailgate rotation axis (hinge T5) of the tailgate A in the closed state (A1). When the tailgate A opens and closes around the tailgate rotation axis T5, bracket B moves while rotating together with the tailgate A around the pivot point R1 with the first arm 1.

[0024] The first arm 1 has one end (upper end) pivotally attached to the bracket B, and the other end (lower end) pivotally attached to the link portion 3 at a position lower than the tailgate rotation axis T5. In this embodiment, the pivot point R1 of the first arm 1 with respect to the bracket B is set at a predetermined height position on the outward-facing surface A3 of the tailgate A in the closed state (A1). The "outward-facing surface A3 of the tailgate A in the closed state (A1)" is the surface of the tailgate A in the closed state (A1) that faces the cargo compartment (inward-facing surface A4). Furthermore, the "vertical direction" in the description of the first arm 1, etc., is the direction that coincides with the vertical direction when the tailgate A is in the closed state (A1), which is the +90-degree upright position shown in Figures 2 and 3.

[0025] The second arm 2 is positioned in the space below the frame T4 that surrounds the floor T6 of the cargo compartment, and rotates around a fixed axis RF1 (first fixed axis RF1). In this embodiment, the fixed axis RF1 of the second arm 2 is set inward (towards the center of the width direction W) of the tailgate rotation axis (hinge T5) in the width direction W of the cargo bed T1, and below the tailgate rotation axis (hinge T5) in the height direction H. The tip (upper end) of the second arm 2 is pivotally attached to the link part 3, and the third arm 4, which swings around the second fixed axis RF2, is connected to the tip of the rod M1 near the longitudinal center of the second arm 2, and the third arm 4 and the second arm 2 are connected via a connecting arm 5. An auxiliary power spring mechanism M3 that provides auxiliary power is arranged around the actuator M (rod M1).

[0026] The actuator M is positioned in the space below the frame T4 and rotates the fixed shaft RF1 via a power transmission mechanism (for example, a mechanism using sprockets S1, S2 and a chain C1 installed axially on the fixed shaft RF1 and the drive motor M2) using the rotational force of the drive motor M2. The drive motor M2 and the power transmission mechanism (sprocket S2) are connected via appropriate gears. As the drive motor, motors other than DC motors, such as AC motors and servo motors, can be used. Furthermore, any power transmission mechanism that can transmit the rotational force of the motor to the fixed shaft RF1 can be used, and the motor type can be rotary or linear. The third arm 4 swings around the second fixed shaft RF2. The second arm 2, which is connected to the third arm 4 via a connecting arm 5, rotates around the first fixed shaft RF1 in conjunction with the swing of the third arm 4. Therefore, when the tailgate A is in the closed state (A1), which is the +90-degree upright position shown in Figures 2 and 3, the actuator M is driven, causing the second arm 2 to rotate and the link section 3 to operate, and the first arm 1 to move downward, so that the tailgate A gradually changes from the closed state (A1) to the open state (A2) shown in Figure 9. The mechanical configuration of the link section 3 is described in detail below. In addition, the first fixed shaft RF1 of the second arm 2 and the second fixed shaft RF2 of the third arm 4 in this embodiment are rotatably supported in a box GB that can house them.

[0027] The second arm 2 rotates around the fixed axis RF1, and the pivot point R2 with the link section 3 also moves, causing the link section 3 to operate.

[0028] The link section 3 consists of a plurality of links 31, 32, and 33, which are deployed or folded as the second arm 2 rotates, thereby increasing or decreasing the distance between the first arm 1 and the second arm 2. The link section 3 in this embodiment includes a main link 31, one end of which is pivotally attached to the first arm 1 and the portion located a predetermined distance from the one end of which is pivotally attached to the second arm 2; a first lock link 32, one end of which is pivotally attached to the other end of the main link 31; and a second lock link 33, one end of which is pivotally attached to the other end of the first lock link 32 and the other end of which is pivotally attached to a predetermined portion of the second arm 2.

[0029] The main link 31 has a "V" shape with a bent section in the center, with one end set as the pivot point R3 for the first arm 1, the other end set as the pivot point R4 for the first lock link 32, and the bent section set as the pivot point R2 for the second arm 2.

[0030] The first lock link 32 has one end set to pivot point R4 on the main link 31 and the other end set to pivot point R5 on the second lock link 33.

[0031] The second lock link 33 has one end set to pivot point R5 on the first lock link 32 and the other end set to pivot point R6 on the second arm 2.

[0032] When the tailgate A is in the closed state (A1) as shown in Figure 3, the main link 31, the first lock link 32, and the second lock link 33 are folded relative to each other, and this state is the stored position (3S) of the link section 3. When the link section 3 is in the stored position (3S), the pivot point R2 of the main link 31 and the second arm 2 is directly above or approximately directly above the pivot point R3 of the main link 31 and the first arm 1. Furthermore, the pivot point R1 of the bracket B and part of the first arm 1 is positioned approximately directly above the pivot point R2 of the main link 31 and the second arm 2, so that part of the first arm 1 is in an upright position at approximately 90 degrees, and the link section 3 (main link 31, first lock link 32, second lock link 33) and the second arm 2 are positioned in the area closer to the center W in the width direction of the cargo bed T1 than the outward-facing surface A3 of the first arm 1.

[0033] When changing the closed state (A1) of tailgate A to the open state (A2), or when changing the open state (A2) of tailgate A to the closed state (A1), the actuator M is driven based on an appropriate command. Specifically, when a higher-level controller (control unit C) receives a drive command (such as "open the tailgate" or "close the tailgate," which is synonymous with the opening / closing command shown in Figure 2) based on a drive command input operation by an operator (such as a truck driver) to an appropriate button, switch, or input device such as a touch panel, the control unit C drives and controls the motor M2 based on the angle of tailgate A, thereby automatically opening and closing tailgate A.

[0034] When the tailgate A is in the closed position (A1), which is the +90-degree upright position shown in Figures 2 and 3, driving the actuator M to rotate the fixed axis RF1 of the second arm 2 causes the link section 3 to switch from the retracted position (3S) shown in Figure 3 to the extended position (3T) shown in Figure 4 as the second arm 2 rotates, and the first arm 1 takes on an inclined position with its lower end, which is the pivot point R3 with the link section 3, extending outward (in the direction away from the center of the width W). In this embodiment, the inclination angle θ (inner angle) of the first arm 1 with respect to the tailgate A at this point is set to, for example, 15 degrees.

[0035] The operation by which the link section 3 switches from the retracted position (3S) to the extended position (3T) in conjunction with the rotation of the second arm 2 is as follows. Specifically, as the second arm 2 rotates, the main link 31 of the link section 3 tilts around the pivot point R2 with the second arm 2, and the pivot point R3 with the first arm 1 switches to a position where it is outside the pivot point R2 with the second arm 2. More specifically, when the second arm 2 begins to rotate, the first lock link 32 and the second lock link 33 of the link section 3 tilt in a direction away from each other around their respective pivot points R5, and when a certain tilt angle is reached, as shown in region Q1 of Figure 6(a), the contact parts 32a and 33a provided on both lock links (first lock link 32 and second lock link 33) come into contact with each other, restricting further movement of both lock links (first lock link 32 and second lock link 33) in the direction of expansion (opening). The change in posture of the link section 3 from the retracted position (3S) to the extended position (3T) is completed when the contact portions 32a and 33a, respectively, provided on both lock links (first lock link 32 and second lock link 33), come into contact with each other. At this point, the second arm 2 changes from the initial position shown in Figures 2 and 3 (standing upright and diagonally upward) to the reclined position shown in Figure 4, and the main link 31 of the link section 3 extends further outward from the tip of the second arm 2. In other words, when the link section 3 is in the extended position (3T), the second arm 2 takes on an extended form (extended second arm form) when the main link 31 is considered as part of the second arm 2. Figure 5 shows an enlarged perspective view of the main parts of Figure 4, with some parts (such as the axes defining each pivot point (connecting axes)) omitted.

[0036] When the actuator M is driven to rotate the fixed shaft RF1, the second arm 2 tilts, and from the point where the second arm is in the extended position, if the second arm 2 further tilts in the same direction (forward direction) around the fixed shaft RF1, the movement of each link of the link section 3 (main link 31, first lock link 32, second lock link 33) toward opening each other is restricted by the contact between the contact parts 32a and 33a, and the movement of each link of the link section 3 (main link 31, first lock link 32, second lock link 33) toward folding each other is restricted by the bracing posture maintenance part 6. The bracing posture maintenance part 6 comprises a lock pin 61 (corresponding to the "lock part" in this invention), a lock pin arm 62, and a lock release claw 63 (corresponding to the "lock release part" in this invention). In this embodiment, as shown in region Q2 of Figure 6(b), a lock pin 61 is positioned near the pivot point R5 of both lock links (first lock link 32, second lock link 33). The lock pin receivers 32b and 33b, respectively, provided on the first lock link 32 and the second lock link 33, sandwich the lock pin 61 (locking part 61), thereby maintaining the extended position (3T) even when a force is applied to return the link part 3 to the retracted position (3S). Thus, the extended position maintenance part 6 of this embodiment includes a locking part 61 that restricts the change in the position of the link part 3 from the extended position (3T) to the retracted position (3S). The tailgate opening and closing mechanism X according to this embodiment is configured to lock the link part 3 in the extended position (3T) by the lock pin 61 and the lock pin receivers 32b and 33b provided on the first lock link 32 and the second lock link 33.

[0037] With the above configuration, when the actuator M is driven and the second arm 2 tilts, and after the second arm 2 reaches the extended position, if the second arm 2 further tilts in the same direction (positive direction) around the fixed axis RF1, the pivot point R3 between the first arm 1 and the link part 3 moves downward as the second arm 2 tilts while maintaining the extended position, and the first arm 1 is pulled downward, thereby moving the tilt A from the +90 degree upright position shown in Figure 4 to the 0 degree reclining position shown in Figure 8. Furthermore, by rotating the second arm 2 in the same direction (positive direction) around the fixed axis RF1 while it remains in the extended position, the tilt A can be moved to the open state (A2) shown in Figure 9 (a -85 degree hanging position in this embodiment).

[0038] By opening the tailgate A (A2), loading and unloading operations can be performed on the cargo bed T1, and after the loading and unloading operations are completed, the tailgate A is switched from the open state (A2) to the closed state (A1). This switching process involves operating the tailgate A in the order shown in Figures 9, 8, 4, and 3. Even during this switching process, the lock pin 61 of the bracing posture maintenance unit 6 locks the link unit 3 in the braced position (3T) (restricting the operation of the link unit 3 in the braced position), thus maintaining the second arm extension configuration until the state shown in Figure 4 is reached. Furthermore, the tailgate opening and closing mechanism X according to this embodiment is configured such that when the state changes from the state shown in Figure 9 to the state shown in Figure 8 and then to the state shown in Figure 4, that is, when the tailgate A has finished switching from the open state (A2) to the closed state (A1) shown in Figure 4, the lock state (tensioned posture maintenance state) of the tensioned posture maintenance part 6 by the lock pin 61 is released by the lock release claw 63 (corresponding to the "lock release part" in this invention). In this embodiment, as shown in region Q3 of Figure 7(a), the lock pin arm 62 of the bracing posture maintenance unit 6 has a lock pin 61 at its tip that fits into the lock pin receivers 32b and 33b of both lock links (first lock link 32 and second lock link 33). A lock release claw 63 is provided on the side opposite to the lock pin 61, and by applying a predetermined force by the lock release operating unit 7 to this lock release claw 63, the lock pin 61 is dislodged from the lock pin receivers 32b and 33b of both lock links (first lock link 32 and second lock link 33), as shown in region Q4 of Figure 7(b). The lock release mechanism 7 consists of, for example, a metal wire body 71 with a holder 72, and a release pin 73 on the holder 72. By pulling the wire body 71 in a predetermined direction (direction of arrow 7A in Figure 7(a)) while the release pin 73 is hooked onto the lock release claw 63, the lock pin arm 62 is rotated in a predetermined direction. When the lock pin arm 62 is rotated in the predetermined direction, the lock pin 61 is configured to disengage from the lock pin receivers 32b and 33b of both lock links (first lock link 32 and second lock link 33).Thus, the tailgate opening and closing mechanism X according to this embodiment includes a tensioned posture maintenance unit 6 that releases the locked state (tensioned posture maintenance state) by the lock pin 61 using a lock release claw 63.

[0039] In this embodiment, after the tensioned posture maintenance state of the link section 3 by the tensioned posture maintenance section 6 is released, when the second arm 2 rotates around the fixed axis RF1 in the direction from the reclining posture shown in Figure 4 to the upright posture (reverse direction), as shown in Figure 3, the change in posture of the link section 3 is not restricted by the lock pin 61, so the link section 3 switches from the tensioned posture (3T) to the retracted posture (3S). As a result, the extended form of the second arm is also broken, and the link section 3 and the second arm 2 can be stored in the space that is inside the width direction W (towards the center of the width direction W) of the outward-facing surface A3 of the first arm 1 in the upright posture, and in the space below the cargo bed T1.

[0040] As described above, the tailgate opening and closing mechanism X according to this embodiment is provided with a link section 3 between the first arm 1 and the second arm 2, and this link section 3 is configured to change its position between a braced position (3T) and a retracted position (3S). When the tailgate A is in the closed state (A1), the second arm 2 rotates around the fixed axis RF1 in conjunction with the drive of the actuator M, causing the link section 3 to switch from the retracted position (3S) to the braced position (3T). The second arm 2 continues to rotate while maintaining the braced position (3T) with the braced position maintenance section 6, thereby switching the tailgate A from the closed state (A1) to the open state (A2). In other words, according to the tailgate opening and closing mechanism X of this embodiment, by setting the link portion 3 provided between the first arm 1 and the second arm 2 into a braced position (3T), the lower end of the first arm 1 can be moved to a position further from the center of the width direction W of the cargo bed T1 than the outward-facing surface A3 of the tailgate A. While this braced position (3T) is maintained by the braced position maintenance portion 6, the second arm 2 appears to be extended by the amount of the link portion 3, and by giving the tailgate A and the first arm 1 a predetermined angle θ, a state in which the tailgate A is supported can be ensured, and force can be transmitted to the tailgate A. As a result, an automatic tailgate opening and closing mechanism X can be realized in which the tailgate A switches smoothly from a closed state (A1) to an open state (A2) without sudden movement.

[0041] Here, Figure 10 shows the mechanism of a conventional tailgate opening and closing assist device. In this figure, the same reference numerals are used for each part and corresponding part in the tailgate opening and closing mechanism X of this embodiment.

[0042] As shown in Figure (a), in a conventional structure where the lower end of the first arm 1, which takes an upright position when the tailgate A is in the closed state (A1), is directly pivoted (pivot point Rx) to the second arm 2, the force acting on the pivot point R1 of the bracket B and the first arm 1 is dominated by the force AF acting in the width direction W of the tailgate A and the force 1F acting in the height direction H of the tailgate A. Therefore, even when the second arm 2 begins to rotate around the fixed axis RF1, a state occurs where the tailgate A does not move, and as shown in Figure (b), the tailgate A suddenly opens when the force AF becomes large enough to open the tailgate A due to the rotational force of the second arm 2, making smooth opening and closing impossible.

[0043] On the other hand, according to the tailgate opening and closing mechanism X of this embodiment, after the actuator M is driven and the second arm 2 begins to rotate around the fixed axis RF1, it transitions to a configuration in which the second arm 2 is extended by the link portion 3 provided between the first arm 1 and the second arm 2 (second arm extended configuration). As a result, as shown in Figure 11, a force 2F acts on the pivot point R1, and the force AF acting in the width direction W of the tailgate A is larger than in Figure 10(a). As a result, the tailgate opening and closing mechanism X of this embodiment can prevent the tailgate A from moving suddenly and can perform the opening and closing operation of the tailgate A smoothly.

[0044] In other words, the inventors have found that in order to eliminate the problems that arise with conventional structures, it is essential to actively eliminate the configuration in which the tailgate A and the first arm 1 are aligned approximately parallel in an upright position before the tailgate A begins to open, and instead to tilt the first arm 1 relative to the tailgate A by a predetermined angle θ, thereby creating an angle between the tailgate A and the first arm 1.

[0045] Here, two specific configurations for creating an angle between the tailgate A and arm A can be described: 1) The pivot point R1 of the bracket B and the first arm 1 is set to be further outward in the width direction W of the truck T than the tailgate A in the closed state (A1), that is, set to the outward-facing surface A3 of the tailgate A in the closed state (A1) (Condition 1); and 2) The pivot point of the first arm 1 and the second arm 2 is set to be further outward in the width direction W of the truck T than the outward-facing surface A3 of the tailgate A in the closed state (A1) (Condition 2). However, a configuration in which parts protrude to the side of the truck T results in a reduction in the width of the cargo bed T1. Therefore, in this embodiment, as described above, a link section 3 that can expand and contract freely is provided between the first arm 1 and the second arm 2, and the link section 3 is changed from a retracted position (3S) to a braced position (3T) to extend the second arm 2, thereby satisfying conditions 1 and 2. As a result, the tailgate opening and closing mechanism X according to this embodiment allows the tailgate A to be supported from the outside of the truck T, compared to the conventional configuration shown in Figure 10. Furthermore, by storing the link section 3 in a retracted position (3S) when the tailgate A is fully closed, the size of the first arm 1 and the second arm 2 during normal use other than tailgate opening and closing operations can be kept at approximately the same level as the conventional configuration. This avoids the situation where the width of the cargo bed T1 is reduced and the maximum load capacity is decreased due to the configuration in which parts protrude to the side of the truck T. Moreover, the tailgate opening and closing mechanism X according to this embodiment can be retrofitted to the truck T, and the opening and closing operation of the tailgate A can be motorized without significantly changing the size, making it easy to introduce to sites where automation of truck loading and unloading operations is required.

[0046] Furthermore, according to the tailgate opening and closing mechanism X of this embodiment, a lock release claw 63 (lock release part) is provided to release the locked state (a state that restricts the change of posture of the link part 3 from the extended posture (3T) to the stored posture (3S)) by the lock pin 61 (lock part 61) of the braced posture maintenance part 6, and when the tailgate A has finished switching from the open state (A2) to the closed state (A1), the lock release operating part 7 is activated to apply a predetermined force to the lock release part 63 to release the locked state (braced posture maintenance part 6) by the lock part 61 (braced posture maintenance part 6). Since it is configured to release the (stretched posture maintenance state), the locking part 61 maintains the locked state (stretched posture maintenance state) while switching the tailgate A between the open state (A2) and the closed state (A1). When the tailgate A is in the closed state (A1), that is, when it is in the +90 degree upright position shown in Figure 4, the lock release part 63 releases the operating restriction state of the link part 3, and the link part 3 switches from the stretched posture (3T) to the retracted posture (3S), allowing the link part 3 to be stored within the width of the vehicle.

[0047] In particular, according to the tilt opening / closing mechanism X of this embodiment, the link portion 3 includes a main link 31 with one end set to pivot point R3 on the first arm 1 and pivot point R2 on the second arm 2 at a predetermined distance from pivot point R3, a first lock link 32 with the other end set to pivot point R4 on the main link 31, and a second lock link 33 with one end set to pivot point R5 on the first lock link 32 and the other end set to pivot point R6 on the second arm 2. By applying a configuration that includes the above, the bracing posture maintenance part 6 is equipped with a lock pin 61 (lock part 61) that fits between the first lock link 32 and the second lock link 33 which are mutually expanded around the pivot point R5 in the link part 3 in the bracing posture (3T), and the lock pin 61 restricts the movement of the first lock link 32 and the second lock link 33 in the direction in which they fold each other. Therefore, the link part 3 and the bracing posture maintenance part 6 can be realized with a relatively simple configuration, which is preferable.

[0048] Furthermore, it is also possible to configure the tilt mechanism A so that its position in the open state (A2) is -90 degrees. In addition, the opening and closing operation of the tilt mechanism A by the tilt mechanism X is not limited to switching from the closed state (A1) to the open state (A2), or from the open state (A2) to the closed state (A1), but also includes switching from the closed state (A1) or the open state (A2) to any tilt angle A (any angle within the range of -89 degrees to +89 degrees), switching from any tilt angle A to the closed state (A1) or the open state (A2), and switching between any tilt angles A.

[0049] Although embodiments of the present invention have been described above, the present invention is not limited to the configuration of the above embodiments. For example, the configurations shown in Figures 12 to 17 can be used as the link portion and the bracing posture maintenance portion. The following figures are enlarged views of the main parts corresponding to Figure 4, and the same reference numerals are used for the parts corresponding to each part in the tailgate opening / closing mechanism X of the above embodiment.

[0050] The link section 3 shown in Figure 12 comprises a main link 31 with one end set to a pivot point R3 on the lower end of the first arm 1 and the other end set to a pivot point R2 on the tip of the second arm 2, and a first lock link 32 having a locking claw 32c (locking part) that can engage with a hooking part 31c provided on the other end of the main link 31. The braced posture maintenance section 6 in the configuration shown in Figure 12 is equipped with a locking claw 32c (locking part), and the state in which the locking claw 32c is engaged with the hooking part 31c is the braced posture (3T) of the link section 3, and by maintaining this braced posture (3T), the extended form of the second arm can be secured. Furthermore, according to the configuration shown in Figure 12, by pushing a part of the first lock link 32 (the end of the first lock link 32 opposite to the end on which the lock claw 32c is provided) 32d with the lock release operating unit 7, the engagement state of the lock claw 32c with the hook portion 31c (the locked state by the lock portion) can be released, and the link portion 3 can be switched from the extended position (3T) to the retracted position (3S). In other words, the bracing posture maintenance section 6 shown in Figure 12 includes a lock release section (end part 32d of the first lock link 32) that releases the restriction on the operation of the link section 3 by the lock claw 32c (locking section). While switching the tailgate A between the open state (A2) and the closed state (A1), the lock state (bracing posture maintenance state) by the lock claw 32c (locking section) is maintained. At the point when the tailgate A moves from the open state (A2) to the closed state (A1) (when it reaches a +90 degree upright position), the restriction on the operation of the link section 3 is released by the end part 32d (lock release section) of the first lock link 32, and the link section 3 switches from the bracing posture (3T) to the retracted posture (3S), allowing the link section 3 to be retracted within the width of the vehicle.

[0051] Furthermore, the link section 3 shown in Figure 13 comprises a main link 31 with one end set to pivot point R3 on the lower end of the first arm 1 and a bent portion set to pivot point R2 on the tip of the second arm 2, and a first lock link 32 with one end pivotally attached to the other end of the main link 31 and having a hollow lock guide hole 32e in a predetermined area. The state in which the guide pin 64 is inserted into one end 32f of the lock guide hole 32e is the extended position (3T) of the link section 3, and the extended position maintenance section 6 in the configuration shown in Figure 13 maintains the extended position (3T) by making one end 32f of the lock guide hole 32e function as a locking part. In addition, the inserted state of the guide pin 64 (extended position maintenance state) can be released by moving the guide pin 64 out of one end 32f of the lock guide hole 32e by appropriate means (lock release operation section) not shown, and the link section 3 can be switched from the extended position (3T) to the retracted position (3S). In other words, the braced posture maintenance section 6 shown in Figure 13 includes a lock release section (the area of ​​the lock guide hole 32e excluding the end 32f) that releases the restricted operation state of the link section 3, in which a guide pin 64 is inserted into one end 32f (locking section) of the lock guide hole 32e. While switching the tailgate A between the open state (A2) and the closed state (A1), the lock state (braced posture maintenance state) is maintained with the guide pin 64 inserted into one end 32f (locking section) of the lock guide hole 32e. At the point when the tailgate A moves from the open state (A2) to the closed state (A1) (when it reaches a +90 degree upright position), the restricted operation state of the link section 3 is released by moving the guide pin 64 out of the end 32f (locking section) of the lock guide hole 32e, and the link section 3 switches from the braced posture (3T) to the retracted posture (3S), allowing the link section 3 to be retracted within the width of the vehicle.

[0052] Furthermore, the link section 3 shown in Figure 14 has a configuration similar to the link section 3 shown in Figure 13, and the state in which the guide pin 64 is fitted into one end 32f (locking part) of the lock guide hole 32e formed in the first lock link 32 is the braced position (3T) of the link section 3. The braced position maintenance section 6 in the configuration shown in Figure 14 maintains this braced position (3T) by making one end 32f of the lock guide hole 32e function as the locking part, and is characterized by exhibiting an automatic locking function that releases the fitted state of the guide pin 64 (braced position maintenance state) by swinging the first lock link 32 around the pivot point R4 with the main link 31, thereby automatically moving the guide pin 64 from one end 32f to the other end 32g (unlocking part) of the lock guide hole 32e.

[0053] Furthermore, the link section 3 shown in Figure 15 comprises a main link 31 with one end set to a pivot point R3 with respect to the lower end of the first arm 1 and a bent portion set to a pivot point R2 with respect to the tip of the second arm 2, and a first lock link 32 with one end pivotally attached to the other end of the main link 31 and having a hollow lock guide hole 32e in a predetermined area. The bracing posture maintenance section 6 in the configuration shown in Figure 15 maintains the braced posture (3T) by having one end 32f of the lock guide hole 32e function as a locking part. That is, the braced posture (3T) of the link section 3 is the state in which the connecting shaft 65 that defines the pivot point R4 between the main link 31 and the first lock link 32 is fitted into one end 32f of the lock guide hole 32e, and by maintaining this braced posture (3T), the extended form of the second arm can be secured. Furthermore, the first lock link 32 swings, moving the connecting shaft 65 from one end 32f of the lock guide hole 32e to the other end 32g (unlocking part), thereby releasing the engaged state (locked state by the locking part) of the connecting shaft 65, and switching the link part 3 from the extended position (3T) to the retracted position (3S). In other words, the braced posture maintenance unit 6 shown in Figure 15 is equipped with a lock release unit (the other end 32g of the lock guide hole 32e) that releases the restricted operation state of the link unit 3, in which the connecting shaft 65 is fitted into one end 32f (locking part) of the lock guide hole 32e. While switching the tailgate A between the open state (A2) and the closed state (A1), the locked state (braced posture maintenance state) with the connecting shaft 65 fitted into one end 32f (locking part) of the lock guide hole 32e is maintained. At the point when the tailgate A moves from the open state (A2) to the closed state (A1) (when it reaches a +90 degree upright position), the restricted operation state of the link unit 3 is released by moving the connecting shaft 65 from one end 32f (locking part) of the lock guide hole 32e to the other end 32g, thereby switching the link unit 3 from the braced posture (3T) to the retracted posture (3S), allowing the link unit 3 to be retracted within the width of the vehicle.

[0054] Furthermore, the link section 3 shown in Figure 16 has substantially the same configuration as the embodiment described above, and the state in which the contact portions 32a and 33a of the first lock link 32 and the second lock link 33 are in contact with each other is the braced position (3T) of the link section 3. The braced position maintenance section 6 in the configuration shown in Figure 16 maintains the braced position (3T) by making the contact portions 32a and 33a of the first lock link 32 and the second lock link 33 function as a locking section. The braced posture maintenance section 6 shown in Figure 16 is provided with a lock release claw 64 (lock release section) on the second lock link 33. By pressing this lock release claw 64 with an appropriate means (lock release operating section), the second lock link 33 swings, which releases the contact state (braced posture maintenance state) between the contact portions 32a and 33a of the first lock link 32 and the second lock link 33, and allows the link section 3 to be switched from the braced posture (3T) to the retracted posture (3S). In other words, the bracing posture maintenance unit 6 shown in Figure 16 is equipped with a lock release unit (lock release claw 64) that releases the operating restriction state of the link unit 3 when the contact portions 32a, 33a (locking parts) of the first lock link 32 and the second lock link 33 come into contact with each other, and while switching the tailgate A between the open state (A2) and the closed state (A1), the contact portions 32a, 33a (locking parts) of the first lock link 32 and the second lock link 33 come into contact with each other in a locked state. While maintaining the braced position, when the tailgate A moves from the open position (A2) to the closed position (A1) (when it reaches a +90 degree upright position), the lock release claw 64 (lock release part) is activated to release the contact between the contact parts 32a and 33a (lock parts) (the restriction on the operation of the link part 3), and the link part 3 switches from the braced position (3T) to the retracted position (3S), allowing the link part 3 to be stored within the width of the vehicle.

[0055] Furthermore, the link section 3 shown in Figure 17 is a quadrilateral link mechanism, such as a parallelogram or trapezoid, formed by three links 34, 35, and 36 and the second arm 2. The state in which it extends in the width direction W of the track T is the extended position (3T), and by maintaining this extended position (3T) with the cam 61 (locking part), the extended form of the second arm can be secured. In the configuration shown in Figure 17, the extended position maintenance part 6 uses the cam 61 of the locking cam mechanism as a locking part, and by releasing the locked state (extended position maintenance state) of the cam 61 as the center of gravity moves due to the operation of the link mechanism, the link section 3 can be switched from the extended position (3T) to the retracted position (3S) (a state in which the link mechanism extends in the height direction of the track T). In other words, the bracing posture maintenance unit 6 shown in Figure 17 maintains a locked state (bracing posture maintenance state) by the cam 61 (locking unit) while switching the tailgate A between the open state (A2) and the closed state (A1). When the tailgate A moves from the open state (A2) to the closed state (A1) (when it reaches a +90 degree upright position), the cam 61 disengages, and as a result the restriction on the operation of the link unit 3 is released. This allows the link unit 3 to switch from the bracing posture (3T) to the retracted posture (3S), thereby allowing the link unit 3 to be retracted within the width of the vehicle.

[0056] The tailgate opening and closing mechanism according to the present invention is not limited to the electric type that utilizes the driving force of the actuator described above, but may also be a type that uses a hydraulic cylinder or the like to drive hydraulically instead of a motor mechanism, or a mechanism that automatically opens and closes the tailgate using a mechanical mechanism that utilizes the weight of the tailgate itself.

[0057] Furthermore, the tailgate opening and closing mechanism according to the present invention can automatically open and close the tailgate so that the tilting speed (opening and closing speed) of the tailgate from the time it starts to open when it is in the closed state until it reaches a predetermined angle is at a predetermined speed. For example, it is also possible to configure the mechanism so that the tilting speed (opening and closing speed) from the time it starts to open until it reaches a predetermined angle is made faster or slower.

[0058] Regarding the inclination angle θ of the first arm relative to the closed tailgate, in the embodiment described above it is set to 15 degrees, but it is possible to set it to an appropriate angle depending on various specifications. It is important to ensure that the horizontal force of the first arm is secured when the tailgate begins to open, and that the first arm 1 is of a size (length) that can be stored under the cargo bed when the tailgate is fully opened (open state) (if the first arm is made longer to give it an angle, there is a possibility that the first arm will not be able to be stored under the cargo bed when the tailgate is fully opened (open state)).

[0059] The cargo vehicles on which the tailgate opening and closing mechanism of the present invention can be implemented are not limited to trucks (classified according to load capacity as small trucks (2-ton and 3-ton trucks), medium trucks (4-ton trucks), large trucks (10-ton trucks), and light trucks), but can also be implemented in cargo vehicles T such as trailers and dump trucks.

[0060] In the embodiments described above, side panels (side panels) that define the sides of the cargo bed were used as an example of tailgates. However, the tailgate opening and closing operation of the rear panel that defines the rear of the cargo bed can also be performed by the tailgate opening and closing mechanism according to the present invention. Note that tailgates are also referred to as gates (side gates, back gates).

[0061] In the above embodiment shown in Figure 7(a), the lock release mechanism 7 is configured to release the lock state by pressing the lock release claw 63 with the release pin 73, causing the lock pin 61 to disengage from the lock pin receivers 32b and 33b of both lock links (first lock link 32 and second lock link 33). However, this configuration may also be modified as appropriate. For example, in one modified example shown in Figure 16, a lock release claw 64 (lock release part) is provided on the second lock link 33, and the wire body 71 of the lock release mechanism 7, similar to that in Figure 7(a), is pulled in a predetermined direction (the direction of arrow 7B in Figure 16, which is the opposite direction to arrow 7A in Figure 7(a)), thereby moving (rotating) the lock release claw 64 in a predetermined direction. With this configuration, the contact state (stabilized position maintenance state) between the contact portions 32a and 33a (locking portions) of the first lock link 32 and the second lock link 33 can be released, and the link portion 3 can be switched from the stabilized position (3T) to the retracted position (3S).

[0062] Furthermore, instead of using a mechanical mechanism to release the lock state of the link section (activating the lock release unit) as the lock release actuation unit, a configuration using an electromagnetic mechanism (solenoid or clutch) to release the lock state of the link section (activating the lock release unit) may be adopted. In that case, the solenoid or clutch is driven based on an appropriate command to release the lock state of the link section 3. Specifically, when a higher-level controller (control unit C) receives a drive command based on the drive command input operation when driving the actuator M (a command such as "close the tailgate," which is synonymous with the opening / closing command shown in Figure 2), the control unit C can drive and control the solenoid or clutch based on that command to automatically release the lock state of the link section 3.

[0063] Furthermore, the lock release claw 64 (lock release part) shown in Figure 16 was positioned closer to the cargo bed (upper position) than the contact parts 32a and 33a (lock parts) of the first lock link 32 and the second lock link 33 in the height direction of the cargo bed. However, as shown in Figure 18, it may be positioned further from the cargo bed (lower position) than the contact parts 32a and 33a (lock parts). In this case, as shown in Figure 18, the lock release actuation part can be simplified by, for example, installing the solenoid SD1 (lock release actuation part) near the axis of the fixed shaft RF1, which leads to miniaturization of the tailgate opening and closing mechanism X. Also, by pressing the lock release claw 64 in the direction of arrow 7C with the solenoid SD1 and maintaining that state, the contact parts 32a and 33a (lock parts) of the first lock link 32 and the second lock link 33 come into contact with each other, and by maintaining this braced posture (3T), the second arm extension form can be secured. Furthermore, by pulling the release claw 64 in the opposite direction to arrow 7C using the solenoid SD1, the contact state (stretched position maintenance state) between the contact portions 32a and 33a of the first lock link 32 and the second lock link 33 can be released, and the link portion 3 can be switched from the stretched position (3T) to the retracted position (3S).

[0064] The tailgate opening and closing mechanisms shown in the above-described embodiment and the modified example in Figure 17 are configured such that the locking part of the bracing posture maintenance section is provided on a separate part (lock arm, lock cam mechanism) from the parts constituting the link section. In the modified examples shown in Figures 12 to 16 and 18, the locking part of the bracing posture maintenance section is provided on a part of the parts constituting the link section. In particular, in the modified examples shown in Figures 12 to 16 and 18, the unlocking part of the bracing posture maintenance section is also provided on a part of the parts constituting the link section.

[0065] Furthermore, the specific configuration of each part is not limited to the above embodiments, and various modifications are possible without departing from the spirit of the present invention. [Explanation of Symbols]

[0066] 1…First Arm 2…Second Arm 3…Link section 31…Main Link 32…First Locklink 33…Second Locklink 61... Lock pin 6...Standing posture maintenance part 7...Lock release section A...Aori A B...Bracket M2...motor T...Cargo vehicle (truck) T1...cargo bed X...Tailgate opening and closing mechanism

Claims

1. This is a tailgate opening and closing mechanism that automatically opens and closes the tailgates installed on the cargo bed of a freight vehicle. The bracket that supports the tailgate, A first arm whose tip is pivotally attached to the bracket and which stands upright in a direction parallel or substantially parallel to the upright direction of the tailgate when the tailgate is in the closed position, A second arm that rotates around a fixed axis in the space below the cargo bed, A link portion provided between the first arm and the second arm, which is capable of changing between a braced position in which the lower end of the first arm is positioned further from the cargo bed than the outward-facing surface of the tailgate, and a retracted position in which the lower end of the first arm is positioned directly below or approximately directly below the pivot point of the first arm relative to the bracket, The device comprises a bracing posture maintenance part that maintains the link part in the braced position, The link section is configured to switch from the retracted position to the extended position by rotating the second arm around the fixed axis when the tailgate is in the closed position. A tailgate opening and closing mechanism characterized in that, after the link portion switches from the stored position to the extended position, the extended position maintenance portion maintains the extended position while switching the tailgate from a closed state to an open state.

2. The tailgate opening and closing mechanism according to claim 1, wherein the bracing posture maintenance part is equipped with a locking part that restricts the change of posture of the link part in the bracing posture.

3. The tailgate opening and closing mechanism according to claim 2, wherein the bracing posture maintenance part is equipped with a lock release part that releases the operating restriction state of the link part by the lock part.

4. The aforementioned link portion, A main link having a first pivot point at one end which is a pivot point for the first arm, and a second pivot point at a predetermined distance from the first pivot point which is a pivot point for the second arm, A first locking link pivotally attached to the other end of the main link, It comprises a second lock link, one end of which is pivotally attached to the first lock link and the other end of which is pivotally attached to the second arm. The aforementioned bracing posture maintenance part, A tailgate opening and closing mechanism according to any one of claims 1 to 3, comprising a lock pin fitted between the first lock link and the second lock link which are mutually expanded around a pivot point in the link portion in the braced position, wherein the lock pin restricts the movement of the first lock link and the second lock link in a direction in which they are mutually folded.

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