JPH0517312Y2 - - Google Patents

Description

[Detailed explanation of the invention] A. Effects of the invention (1) Industrial application field The invention is installed on a vehicle such as a freight vehicle, and is capable of loading and unloading cargo between the receiving surface of the vehicle and the ground. This invention relates to a vehicle loading platform elevating device.

(2) Prior Art In a conventional vehicle, a loading platform is supported via a parallel link mechanism including a tension link and a bending compression link, and the bending compression link is provided with a safety lock mechanism for restraining its bending. When the mechanism operates,
The tension link and the bending compression link maintain a parallel relationship, and by vertically swinging these links, the loading platform can be raised and lowered in a substantially horizontal state, and when the safety lock mechanism is not activated, the bending compression link is A device is already known in which the cargo receiving platform is tilted forward and downward upon landing by allowing bending to facilitate loading and unloading of cargo (see Japanese Patent Laid-Open No. 52-91220).

(3) Problems to be solved by the invention By the way, when the above-mentioned safety lock mechanism is in the non-operating state, when the loading platform touches the ground and tilts forward and downward due to a load on its tip, the bending compression link bends. At the same time, the tip of the link on the receiving platform side moves forward and backward while remaining in contact with the ground, so the lower surface of the tip of the bending compression link gradually wears out, increasing the frictional resistance with the ground surface, and making the loading platform smooth. There is a problem in that not only is tilting movement prevented, but also the life of the refractive compression link is shortened.

The present invention was developed in view of the above circumstances, and uses a rolling roller pivotally supported at the tip of the bending compression link to ensure smooth back-and-forth movement of the bending compression link and to prevent wear at the tip of the bending compression link. It is an object of the present invention to provide a loading platform elevating device for a vehicle that can solve the above-mentioned problems.

B. Structure of the invention (1) Means for solving the problem In order to achieve the above-mentioned object, according to the invention, the base ends of the tension link and the bendable compression link that constitute the parallel link in the vehicle body frame are swung up and down. The support shaft is movably supported and provided at the tip of the tension link, and the load receiving platform is rotatably supported on the support shaft, and one end of the connecting link is pivotally supported, and the other end of the connecting link has a connecting pin. A locking mechanism is attached to the bending compression link to restrain its bending, and when the safety lock mechanism is activated, the tension link and the bending compression link are parallel to each other. While maintaining the relationship, the loading platform is raised and lowered in a substantially horizontal state by the rocking movement of those links, and when the safety lock mechanism is not activated, the loading loading platform is moved forward and downward by allowing the compression link to bend. In a tilting device for lifting and lowering a loading platform for a vehicle, a rolling roller that can land before the tip of the bending link is rotatably attached to the pivot joint between the bending compression link and the connecting link. support

In the above-mentioned construction, the safety lock mechanism may be of any type so long as it has the required function.

(2) Effect According to the above configuration, when the loading platform touches the ground or the platform while the safety lock mechanism is in the inactive state, the rolling roller at the tip of the bending compression link touches the ground and It rolls backwards as the link bends. At this time, the loading platform smoothly tilts forward and downward, and the tip of the bending compression link does not touch the ground, so it does not wear out and its lifespan can be extended.

(3) Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a side view of a freight vehicle V equipped with the loading platform elevating device of the present invention. A cargo box 2 is mounted on the body frame 1 of the vehicle V, and the rear opening of the cargo box 2 is opened and closed by a cargo receiving platform 3 which also serves as a tailgate. It is raised and lowered by device E while being held substantially horizontally.

Next, the structure of the loading platform elevating device E will be explained with reference to FIGS. 1 to 5.

A pair of left and right mounting frames 4, 4, which are concave in side view, are welded to the lower rear end of the vehicle body frame 1, and the tips of these mounting frames 4, 4 are integrally connected by a connecting shaft 5. Furthermore, right and left bearings 6, 6 are integrally provided at the bases of the pair of mounting frames 4, 4, and a hollow rotating shaft 7 is rotatably mounted on these bearings 6, 6, as shown in FIG. supported.

As shown in FIG. 4, a swinging arm 8 is fixed to the center of the hollow rotating shaft 7 in the left-right direction.
A loading platform elevating cylinder C ₁ is connected between the front end of the loading frame and the mounting frame, and the hollow rotating shaft 7 can be rotated via the arm 8 by extending the cylinder C ₁ . Further, compression link arms 9, 9 are fixed to both ends of the hollow rotating shaft 7 in close proximity to the mounting frames 4, 4, respectively. And each compression link arm 9 has a connecting pin 1.
3, the base end of the compression link 10 is rotatably connected. The compression link arm 9 and the compression link 10 constitute a bent compression link 11. A stopper 12 made of a bolt is screwed onto the compression link arm 9, and this stopper 12
is configured to engage the base of the compression link 10 to prevent the compression link 10 from bending downward relative to the compression link arm 9. A safety lock mechanism S, which will be described later, is provided between the compression link arm 9 and the compression link 10, and when this mechanism S is in operation (first and second illustrated positions), the bending compression link 11
is integrated with the stopper 12 to restrain its refraction.

In addition, a pivot shaft 1 is attached to the left and right mounting frames 4, 4 and the bearing arms 14, 14 fixed thereto.
5 and 15, the base ends of the tension links 16 and 16 are connected to each other so as to be able to swing up and down.

The compression link 10 and the tension link 16 both extend in the same direction and have a length that reaches the rear end of the cargo box 2.

Said tension link 16 as clearly shown in FIG.
The distal end portion 16 ₁ is bent upward substantially vertically,
A support shaft 17 is supported by a bearing portion 16 ₂ at the tip thereof,
The base end of the loading platform 3 is pivotally supported on the support shaft 17 via a bracket 18 that is integrally fixed thereto so as to be freely rotatable up and down. In addition, the support shaft 17
One end of the connecting link 19 is rotatably supported in the housing, and a bearing portion 10 ₁ provided at the free end of the compression link 10 is rotatably supported at the free lower end of the connecting link 19 by a connecting pin 20. connected. As clearly shown in FIGS. 2 and 3, a rolling roller 21 having a diameter larger than the bearing portion 10 ₁ of the compression link 10 is rotatably supported on one side of the connecting pin 20 . is used so that when the compression link 10 touches the ground La or the platform P (FIG. 6), it can come into contact with the ground and prevent wear of the link 10.

The hollow rotating shaft 7 and the compression link arm 9
and a refractive compression link 11 consisting of the compression link 10,
A parallel link mechanism L is composed of a pivot shaft 15, a tension link 16, a support shaft 17, a connecting pin 20, etc., and the link mechanism L is extended and contracted at its tip end by expanding and contracting the cargo platform lifting cylinder _C1 . is raised and lowered, so that the cargo receiving platform 3 supported thereon can be raised and lowered between a lowered position shown in the dashed line position A in FIG. .

As shown in FIG. 1, a stopper 23 is fixed to the lower end of the rear edge of the cargo box 2, and the tip of the tension link 16 engages with this stopper 23, thereby regulating the upper limit position of the cargo platform lifting device E. .

A loading platform 3 is provided on the outer surface of the compression link 10.
, in the raised position, that is, the use position (Fig. 1 B position)
A load receiving platform storage mechanism A is provided for rotating the load receiving platform from the storage position to the storage position (position C in FIG. 1). Next, the structure of the mechanism A will be explained mainly with reference to FIGS. 2 and 3. A support pin 24 is attached to the side of the compression link 10 to connect the barrel portion 25 ₁ of the single-acting cylinder C ₂ for storing the cargo tray. The proximal ends are rotatably connected. Single acting cylinder
_C2 extends along the compression link 10, and a push rod 27 is integrally connected to the tip of the piston rod ₂₅₂ via a spring holder 26. The tip of this push rod 27 connects to a bracket 28 that is integrally provided on the outside of the base of the loading platform 3.
are connected to each other by a connecting pin 29. The support pin 24 is located between the spring holders 26.
Both ends of a return spring 30 made of a compression coil spring surrounding the outer circumferences of the barrel portion 25 ₁ and the piston rod portion 25 ₂ of the single acting cylinder C ₂ are connected, and the elastic force of the return spring 30 is applied to the single acting cylinder C 2 . C ₂ is constantly biased in the direction of contraction. Therefore, when the single-acting cylinder C ₂ for storing the loading platform is extended, the loading platform 3 will move around the support shaft 17 into the second cylinder.
By rotating in the direction of the arrow a in the figure, the loading platform 3 can be raised and rotated from a substantially horizontal raised position, that is, a use position B, to a substantially vertical storage position C (solid line position in FIGS. 1 and 2). At this time, the return spring 30 is connected to the extending piston rod portion ₂ of the single-acting cylinder C2.
5 ₂ to protect the piston rod portion 25 ₂ from obstacles. Further, the connecting portion between the barrel portion ₂₅₁ and the return spring 30 is connected to the barrel portion 251.
5 It is protected by the protector 31 provided at ₁ .

When the single-acting cylinder _C2 is released, the elastic force of the return spring 30 operates the single-acting cylinder _C2 in the contraction direction, forcibly rotating the loading platform 3 from the storage position C to the use position B. After this, the loading platform 3 is rotated to the use position B by the elastic force of the return spring 30 and the weight of the loading platform 3. The return spring 30 can be easily replaced by removing either the base end of the barrel portion ₂₅₁ of the single acting cylinder _C2 or the connecting portion at the tip of the piston rod portion.

As shown in FIG. 1, a conventionally known locking mechanism 32 is provided between the left and right rear edges of the cargo box 2 and the right and left sides of the cargo receiving platform 3 for locking the cargo receiving platform 3 in the storage position.

The loading platform elevating device E is provided with a safety lock mechanism S for restraining the bending compression link 11 constituting the parallel link mechanism L so as not to bend or releasing the restraint.

Next, the structure of this safety lock mechanism S will be explained with reference to FIGS. 2 to 5. As clearly shown in FIGS. A safety lever 33 is pivotally supported 34 in a seesaw-like manner in the vicinity of . The tip of this safety lever 33 extends to the upper surface of the base of the compression link 10, while the compression link 1
A locking piece 35 that can be engaged with and disengaged from the tip of the safety lever 33 is fixed to the upper surface of the base of the safety lever 33. A lock spring 36 is stretched between one side of the safety lever 33 and the mounting frame 4, and the elastic force of the lock spring 36 rotates the tip of the safety lever 33 toward the compression link 10, causing the tip to move toward the compression link 10 side. It is biased so as to engage with the locking piece 35. As clearly shown in FIG. 4, a connecting rod 38 is inserted into the hollow rotating shaft 7, and both ends of the connecting rod 38 are rotated by left and right bearing plates 39, 40 fixed to both ends of the hollow rotating shaft 7. Supported freely. A U-shaped left lock lever 41 is integrally formed at the left outer end of the connecting rod 38, and a U-shaped right lock lever 42, which also serves as a handle, is integrally provided at the right outer end. Left side lock lever 4
1 extends above the left safety lever 33 so as to be able to engage on the base of the left safety lever 33, as shown in FIGS. On the other hand, one end of the right lock lever 42 extends above the safety lever 33 so as to be able to engage with the base of the safety lever 33, as shown in FIGS. , 5, a hollow lock pin 43 is fitted so as to be freely protrusive and retractable, and a protrusion spring 44 is provided which urges the lock pin 43 to protrude. On the other hand, the right bearing plate 40 has a lock pin 43.
two first and second pin holes 4 into which the pins can be selectively fitted;
6, 47 are drilled, and when the lock pin 43 is inserted into the first pin hole 46 as shown by the solid line in FIGS. 4 and 5, the left and right safety levers 33, 3
3 are all held in the restraining position by the elastic force of the lock spring 36 and engage with the locking pieces 35, 35 to restrain the bending compression link 11 consisting of the compression link arm 9 and the compression link 10 from bending. .

Furthermore, by grasping the right lock lever 42 which also serves as a handle, and pulling out the lock pin 43 against the elastic force of the protruding spring 44, at the same time rotating the connecting rod 38, and fitting the lock pin 43 into the second pin hole 47,
The left and right lock levers 41 and 42 rotate together to lock the left and right safety levers 3 as shown by the chain lines in FIG.
3 and 33, and their safety levers 3
3, 33 counterclockwise against the elastic force of the lock springs 36, 36 until they hit the stopper 48 as shown by the chain line in FIG. , 10 from the locking pieces 35, 35. As a result of the above, the bending compression link 11 is released from its restraint, and the compression links 10, 10 can now rotate in the direction of the arrow b in FIG. tilting is possible.

Next, referring to FIG. 8, the loading platform lifting cylinder
C ₁ and the single-acting cylinder C ₂ for storing the loading platform, and the hydraulic circuit that operates them will be explained.

A pump P _p driven by a motor M has its suction side connected to an oil sump T, and its discharge side connected to an electromagnetic switching valve V _p
It is connected to the lifting hydraulic line l ₁ and the storage hydraulic line l ₂ via. Further, the discharge side of the pump P _p is also connected to the oil sump T via a relief valve _VR . In addition, one end side is connected to the oil sump T, and the other end side of the return oil line _lp is connected to the lifting hydraulic line _l1 and the storage hydraulic line through the electromagnetic switching valve _Vp with a fixed orifice O _r interposed in the middle. l ₂
It is connected to the. And the electromagnetic switching valve V _p
is always held at a neutral position (the position shown in FIG. 8). When the solenoid Sl is energized, the electromagnetic switching valve V _p is switched to the left position and the pump P _p
is held in a first position where its discharge side is connected to the lifting hydraulic line _l1 and its return oil line _lp is connected to the storage hydraulic line _l2 . When the solenoid Sr is energized, the switching valve V _p is switched to the right position, connecting the discharge side of the pump P _p to the storage hydraulic line l ₂ and connecting the lifting hydraulic line l ₁ to the return oil line l _p The second position is adapted to be held in a second position connected to the second position.

The lifting hydraulic line l ₁ is provided with an electromagnetic switching valve V ₁ equipped with a check valve. When the electromagnetic switching valve V ₁ with a check valve is not energized, the electromagnetic switching valve V 1 maintains the hydraulic oil from the electromagnetic switching valve V _p in the first position where it is supplied to the loading platform lifting cylinder C ₁ via the built-in check valve. When it is energized, it moves to the left position in Fig. 8 and is held in the second position where the hydraulic oil from the cargo platform lifting cylinder _C1 is returned to the three-way electromagnetic switching valve _Vp . .

The storage hydraulic line _l2 is provided with an electromagnetic switching valve _V2 with a check valve. This electromagnetic switching valve V ₂ with a check valve, when not energized, supplies the hydraulic oil from the electromagnetic switching valve V _p to the single-acting cylinder C ₂ for storing the loading platform via the built-in check valve. When energized, it switches to the right position in Fig. 8 and is held in the second position, which returns the hydraulic oil from the single-acting cylinder _C2 for storing the loading platform to the electromagnetic switching valve _Vp . It's getting old.

In the embodiment of the present invention having the above-mentioned configuration, when the pump Pp is operated with the solenoid controlled directional control valve _Vp held in the first position and the solenoid controlled directional control valve _V1 with check _valve held in the first position, the load receiving platform lifting cylinder _C1
At this time, the hollow rotary shaft 7 rotates clockwise in Figs. 1 and 2 together with the arm 8 fixed to the rotary shaft 7. At this time, the tension link 16 of the parallel link mechanism L and the bent compression link 11 in a restrained state both rotate upward, and their tips rise, and the load receiving platform 3 is held in the raised position B shown by the two-dot chain line in Fig. 1. When the load receiving platform 3 is in the raised position B in this way, only the solenoid switching valve _Vp is switched to the second position,
Check valve equipped solenoid switching valve _V2 is set to the first position (position shown in the figure).
When the load-receiving platform is held in this position, hydraulic oil is supplied into the single-acting cylinder _C2 for storing the load-receiving platform, as is clear from FIG.
Then, the single-acting cylinder _C2 for storing the load-receiving platform is extended. At this time, the load-receiving platform 3 is extended as shown by the solid line in FIG.
rotates about the support shaft 17 and is held in a vertical storage position H.

Next, the electromagnetic switching valve V _p is held at the first position, and the electromagnetic switching valve V ₂ with a check valve is energized and held at the second position. Then, due to the elastic force of the return spring 30, the single-acting storage cylinder C ₂ receives a force in the direction of contraction, so the hydraulic oil in the cylinder C ₂ is
The oil sump T is passed through the storage hydraulic line l ₂ 's electromagnetic switching valve V ₂ with check valve, the electromagnetic switching valve V _p , and the return oil line l _p .
Return to Then, the single-acting cylinder for storing the loading platform
C ₂ contracts, and the loading platform 3 begins to rotate around the support shaft 17 from the vertical storage position C toward the horizontal use position C. When the loading platform 3 rotates from a vertical position to an inclined position, a rotational moment due to its own weight acts on the loading platform 3. Therefore, from now on, the rotational moment and the return spring 30
Due to this action, the single-acting cylinder _C2 for storing the loading platform contracts, and the loading platform 3 is held in the horizontal use position B.

By the way, as mentioned above, the rear opening of the cargo box 2 of the vehicle V is closed by the cargo receiving platform 3, that is, the tailgate, which is in the storage position, and in this state, the storage single-acting cylinder C ₂ is closed as shown in FIGS. is in an extended state, and the return spring 30 connected between the barrel part ₂₅₁ and the piston rod part ₂₅₂ of the cylinder _C2 is also extended, and the spring 30 surrounds the outer periphery of the exposed and extended piston rod part ₂₅₂ . be able to.
Therefore, when the vehicle V is running, etc., the loading platform 3
That is, the exposed piston rod portion 25 ₂ of the single-acting storage cylinder C ₂ that holds the tailgate in the storage position can protect its outer periphery from obstacles such as flying stones by the return spring 30. .

Next, when lifting and lowering the loading platform 3 to load and unload cargo, the loading platform 3 is moved above the ground as shown in Figure 6D.
Alternatively, as shown in FIG. 6E, while the cargo receiving platform 3 is being raised or lowered, the receiving platform 3 is grounded on the platform P, and then the receiving platform 3 is tilted forward and downward, and its tip is placed on the ground La. Alternatively, there may be cases where it is desired to land on the platform P so that cargo can be easily loaded and unloaded. It is necessary to remove both S and S to hold the mechanism S and S in the non-operating position. In such a case, as shown in FIG. 4, hold the right lock lever 42 which also serves as a handle, pull out the lock pin 43 from the first pin hole 46, rotate the connecting rod 38, and move the lock pin 43 into the second pin hole 47. (5th
(Fig. 5), the left and right lock levers 41 and 42 at both left and right ends of the connecting rod 38 are rotated to the position where the bending compression link 11 is released (the chain line position in Fig. 5), and the left and right safety levers 33, 33 to the pivot supports 34, 3 against the elastic force of the lock springs 36, 36.
4 in the counterclockwise direction in FIG. 5 until it hits the stopper 48. As a result, the tips of the safety levers 33, 33 are disengaged from the locking pieces 35, 35 on the compression links 10, 10, and the safety lock mechanism S,
Both S are kept in the inactive position. As a result of the above, both the bending compression links 11, 11 can be bent. From this state, if the cargo receiving platform 3 touches the ground La or the platform P and a downward load f acts on its tip, the bending compression consisting of the compression link arm 9 and the compression link 10 will occur as shown in FIG. The link 11 is bent downward in a convex manner while the connecting link 19 is swung around the support shaft 17, so that the load receiving platform 3 can be tilted forward and downward as shown by the chain line in FIG. In this case, the tip of the compression link 10 moves back and forth on the ground La or the platform P, but since the rolling roller 21 is pivotally supported at the tip of the compression link 10, the rolling roller 21
By rolling, the loading platform 3 can be moved smoothly and the compression link 10 is prevented from being worn out.

9 and 10 show a second embodiment of the present invention.

This second embodiment is different from the first embodiment except for the structure of the right lock lever (right end in FIG. 9) fixed to the right outer end of the connecting rod 38. This is the same as the example, and the same members as in the first example are given the same reference numerals.

At the right outer end of the connecting rod 38 is a right lock lever 142 which is bent into a substantially L shape and also serves as a handle.
are provided integrally. The right side lock lever 142
The curved tip of the lock lever 142 extends upwardly so as to be able to engage with the safety lever 33, and a lock pin 143 is fitted into the straight base end of the lock lever 142 via a protruding spring 144 so as to be retractable. Further, a support plate 145 is fixed to the right end of the hollow rotating shaft 7, and first and second pin holes 146 and 147 are bored in the support plate 145, and a lock pin 143 is inserted as shown in solid lines in FIGS. When the safety lever 3 is inserted into the first pin hole 146 as shown in FIG.
3 is engaged with the locking piece 35 by the lock spring 36 and held in a restraining position where the bendable compression link 11 is restrained unbendably, and the lock pin 143 is inserted into the second pin hole 147 as shown by the chain line in FIG. At this time, the safety lever 33 is pushed by the lock lever 142 and rotated counterclockwise in FIG.
5 and holds the bending compression link 11 in the bendable and unrestricted position.

The second embodiment also achieves the same effect as the first embodiment by controlling the rotation of the right lock lever 142, which also serves as a handle, between the restraint position and the restraint release position.

In the embodiment described above, a conventionally known safety lock mechanism S can be used.

C. Effects of the invention As described above, according to the invention, in a loading platform elevating device for a vehicle that is equipped with a parallel link mechanism with a safety lock mechanism, the bending compression link and the connecting link are connected to each other. Since the rolling roller that can land before the tip of the compression link is rotatably supported, the loading platform can smoothly tilt forward and downward when it touches the ground, making loading and unloading work easier. This makes it possible to prevent wear and tear on the bending compression link and extend its lifespan.

[Brief explanation of the drawing]

1 to 8 show a first embodiment of the present invention, and FIG. 1 is a partially cutaway overall side view of the device of the present invention;
Fig. 2 is a side view of the cargo platform elevating mechanism, Fig. 3 is a view taken along the line shown in Fig. 2, Fig. 4 is an enlarged rear view of the cargo platform elevating mechanism along the line shown in Fig. 1, and Fig. 5 is an enlarged rear view of the cargo platform elevating mechanism. , 4th
Figure 6 is a side view showing the lifting/lowering operation state of the loading platform lifting mechanism, Figure 7 is a side view showing the moving status of the loading platform when the safety lock mechanism is unlocked, and Figure 8 is the hydraulic circuit. 9 and 10 show a second embodiment of the present invention, in which FIG. 9 is the same rear view as FIG. 4, and FIG. 10 is a view taken along the X-ray arrow in FIG. 9. S...Safety lock mechanism, 1...Vehicle frame,
3... Loading platform, 11... Bent compression link, 16...
...Tension link, 17... Support shaft, 19... Connecting link, 20... Connecting pin, 21... Rolling roller.

Claims (1)

[Scope of utility model registration request] The base ends of a tension link 16 and a bendable compression link 11 that constitute a parallel link on the vehicle body frame 1 are supported so as to be swingable up and down, and the tension link 16
A support shaft 17 provided at the tip of the support shaft 17 pivotally supports the loading platform 3 so as to be able to rise and fall, and pivotally supports one end of a connecting link 19. A connecting pin 20 is attached to the other end of the connecting link 19.
A safety lock mechanism S is attached to the bending compression link 11 to restrain the bending of the bending compression link 11. When the safety lock mechanism S is activated, the tension link 1
6 and the bending compression link 11 maintain a parallel relationship, and the rocking movement of these links 16 and 11 raises and lowers the loading platform 3 in a substantially horizontal state, and when the safety lock mechanism S is not activated, the loading platform 3 is compressed. Link 1
In the loading platform elevating device for a vehicle, which allows the loading platform 3 to tilt forward and downward by allowing bending of the bending link 11 and the connecting link 19, the bending link 1. A loading/unloading platform elevating device for a vehicle, characterized in that a rolling roller 21 that can land before the tip of the loading roller 11 is rotatably supported.