JP2696503B2 - lift device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lifting device for mounting and dismounting a wheelchair, a trolley or other cargo on a vehicle, and more particularly to a lifting device mounted on a rear portion of a van type car (box type vehicle). The present invention relates to an elevating device suitable for:

2. Description of the Related Art As a lifting device of this type, a device disclosed in Japanese Utility Model Publication No. Sho 63-44272 proposed by the present applicant is conventionally known. This conventional device has a structure in which a platform is attached to a lower end portion of a side frame that is raised and lowered by a parallel link mechanism. By rotating the parallel link, the platform is moved to a landing position and a vehicle body floor surface of a van type car or the like. It can be moved up and down between the substantially coincident ascending positions.

[0003]

[Problems to be Solved by the Invention]
The conventional device of No. 44272 does not disclose any technology for automating the opening / closing (retracting and deploying) of the platform and the undulating operation of the vehicle stop before and after the platform. For this reason, in the conventional device, the operation of opening and closing the platform and the operation of stopping the vehicle before and after the platform must be performed manually.
The operability was poor. In particular, in the case where a wheelchair is placed on a platform to perform an ascending / descending operation, it is desirable to automate the undulating operation of the bogie in terms of safety.

The present invention has been made in view of the above points, and provides an ascending and descending device which automates the opening / closing operation of a platform and the undulating operation of a front and rear brace plate, thereby improving operability and safety. Aim.

[0005] Other objects and novel features of the present invention will be clarified in embodiments described later.

[0006]

In order to achieve the above object, the present invention provides a parallel link mechanism having an upper arm and a lower arm at an opening of a vehicle, and has a side frame pivotally attached to the distal ends of the upper arm and the lower arm. A cylinder is provided at the lower end of the side frame so that the platform can be freely opened and closed from a horizontal open state to a substantially vertical closed state, and the parallel link mechanism is rotated to drive the side frame and the platform up and down. A lifting / lowering device, wherein a two-node link mechanism is connected between an extension extending forward from a pivot point of the platform to the side frame and an intermediate position of the side frame, and the lower arm is used for opening and closing. An opening / closing operation member having an inclined surface is provided, and a contact member provided at an intermediate portion of the two-node link mechanism is moved to the opening / closing inclination member. Has a configuration for opening and closing the platform is brought into contact with the surface.

Further, the opening / closing operation member has a continuous engagement groove at an end of the opening / closing inclined surface, so that the contact member enters the engagement groove when the platform is closed. A lock mechanism for locking the platform in a closed state with respect to the side frame may be provided.

Further, a front brace plate is connected to the front edge of the platform so as to be able to move up and down, and a cam is fixed to the tip of the lower arm. And a front brace plate, and the front brace plate may be held in an upright state during the elevating operation of the platform.

A rear brace plate may be connected to the rear edge of the platform so as to be able to move up and down, and the rear brace plate may be held upright by an up-and-down drive mechanism when the platform is in a non-landing state. Good.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a lifting device according to the present invention will be described below with reference to the drawings.

FIG. 1 is a side view showing an entire configuration of an embodiment of a lifting device according to the present invention. FIG. 2 is a front view of the van-type vehicle (box-shaped vehicle) in a platform closed state, as viewed from the rear.
FIG. 3 is a side view showing the elevating operation of the platform.

In these figures, a base box (base bracket) 1 is fixedly mounted on a floor 10a of a van-type vehicle (box-shaped vehicle) 10, and the base ends of an upper arm 2 and a lower arm 3 having the same length. Are pivotally connected by pins 11 and 12, respectively. Side frames 4 are provided at the tips of the upper arm 2 and the lower arm 3 with pins 13 and 14.
A platform 5 on which a cargo or a wheelchair is mounted is pivotally connected to the lower end of the side frame 4 with a pin 15, and the platform 5 can be freely opened and closed from a horizontal opened state to a substantially vertical closed state. 4 attached. Here, the upper arm 2 and the lower arm 3
Is set equal to the pivot interval between the base box 1 and the side frame 4 to form a parallelogram link mechanism.

As shown in FIG. 4, one end (piston rod side) of a hydraulic cylinder 6 for rotating each of the arms 2 and 3 is provided.
The lower arm 3 is pivotally connected to the lower end of the lower arm 3 via a pin 16 between a pivot point of the upper arm 2 to the base box 1 and a pivot point of the lower arm 3 to the base box 1. The other end of the cylinder 6 is pivotally connected to a pivot point between the upper arm 2 and the side frame 4, that is, a pin 13. When the hydraulic cylinder 6 is a single-acting hydraulic cylinder, a spring for urging the piston rod in the direction of contraction is built in the cylinder. This is to make it possible to smoothly execute the operation of opening the platform 5 horizontally from a state where the platform 5 is closed substantially vertically.

The side frame 4 and the platform 5
Folding handrail members 20 and 21 are connected between the side surfaces of. That is, one ends of the handrail members 20 and 21 are pivotally connected to each other by pins, and the other ends of the handrail members 20 and 21 are pivotally connected to the side frames 4 and the platform 5 by pins. These handrail members 20 and 21 are provided on both sides of the platform 5 in order to prevent a wheelchair, a trolley or the like from falling off the side of the platform.

As can be seen from FIG. 3, when viewed from the vehicle, a front brace plate 31 is provided at the front side of the platform 5 and a rear brace plate 51 is provided at the rear side of the platform 5 via hinges 31a and 51a. It is connected up and down freely.

Referring to FIGS. 4 to 7, a description will be given of an automatic undulating mechanism 30 of the front wheel stopper plate for automatically raising and lowering the front wheel stopper plate 31 in accordance with the platform state.

FIGS. 6 and 7 show the side frame 4 shown in FIGS.
A hole 3 into which pins 13 and 14 respectively fixed to the ends of the upper arm 2 and the lower arm 3 are rotatably fitted.
2 and 33 are formed, and a cam plate 34 for raising and lowering the front brace plate is fixed to a pin 14 integrated with the lower arm 3. Further, a bell crank 36 having a roller 35 as a cam follower abutting on the cam plate 34 at one end thereof is pivotally attached to the side frame 4 with a pin 45. The other end of the bell crank 36 is connected to the upper end of a connection link 37. Further, an up / down drive arm 39 is pivotally attached to the lower end of the side frame 4 with a pin 15, and the lower end of the connection link 37 is pivotally attached to an intermediate position of the up / down drive arm 39. A pin 40 fixed to the tip of the up / down drive arm 39 is engaged with a long hole 42 formed in a reinforcing rib (a portion bent upward) 41 on both sides of the front brace plate 31.

In this case, the platform 5 is shown in FIGS.
The height of the cam plate 34 is substantially the same as the side frame 4 at the position Q in FIG. Since the roller 35 as a cam follower is set in contact with the small portion, the bell crank 36 rotates counterclockwise, and the undulating drive arm 39
Of the vehicle is horizontal, and the front wheel stopper plate 31 is also substantially horizontal, so that a wheelchair, a trolley, and the like can be transferred between the floor 10a of the vehicle and the platform 5 via the front wheel stopper plate 31. Also, the state in which the platform 5 is lower than the ascending limit position indicated by the imaginary line Q in FIGS. 1 and 3 (the floor surface 1 of the van type car 10).
0a), the position R1 in FIGS.
To the cam plate 3 like the side frame 4 at the position R2 in FIG.
4 is set so that a roller 35 as a cam follower abuts on a portion having a large radius.
6 rotates clockwise, the tip of the undulating drive arm 39 is pulled up via the connecting link 37, and the front side brace plate 3 is turned on as shown in the state of the platform landing position indicated by the solid line R in FIG.
1 is in a state of getting up. That is, the front-side stop plate 31 is in an upright state in a range from a position where the platform 5 is slightly lowered from the ascending limit position to a landing position, and the front-side stop plate 31 prevents a wheelchair or a bogie from falling from the front edge of the platform. To prevent.

Referring to FIGS. 8 to 10, a description will be given of an automatic raising and lowering mechanism 50 of the rear wheel stopper plate 51 for automatically raising and lowering the rear wheel stopper plate 51 in accordance with the platform state.

The automatic raising and lowering mechanism 50 of the rear side stopper plate includes
When the platform 5 lands, the rear wheel stopper plate 51 is automatically turned down, and has a function of holding (locking) the rear wheel stopper plate 51 in an upright state in a non-landing state. That is, a perforated engaging plate 52 is fixed to the rear surface near the connecting edge of the rear wheel stopper plate 51, and a substantially V-shaped engaging hole 53 is formed in the engaging plate 52. A mounting bracket 54 is formed on the back side of the rear edge of the platform 5.
The upper end (near one apex of the triangle) of a long and slender triangular landing detection plate 55 is pivotally connected with a pin 56. A landing roller 57 is pivotally attached to a lower end of the landing detection plate 55 (near another vertex of the triangular shape). Then, a pin 58 attached through the vicinity of the remaining apex of the triangular shape of the landing detection plate 55 is attached to the substantially rectangular engagement hole 53 of the engagement plate 52.
Is to penetrate. Note that the rear wheel stopper plate 51
Two torsion bars 60 to urge the
Is provided. One end of each torsion bar 60 is fixed to the back surface of the platform 5, and the other end is engaged with a hook 62 fixed to an end of the engagement plate 52 from above and pushed down. Therefore, as shown by the solid line in FIG.
In the non-landing state, the perforated engagement plate 52 is urged counterclockwise by the torsion bar 60, so that the front end of the rear wheel stopper plate 51 is raised. Further, the landing roller 57 is at a lowered position.

As shown by the solid line in FIG. 9, when the landing roller 57 is not pressed by the ground, the pin 58 provided on the landing detection plate 55 is engaged with the left end locking portion (long The right wall of the left end locking portion of the substantially V-shaped engagement hole 53 even if a force in the downward direction is applied to the rear-side stop plate 51 in the upright state. The portion 53a rises substantially vertically, and only pushes the pin 58 in the lateral direction but does not act to push the pin 58 upward. For this reason, it does not open under the load on the wheelchair side on the platform, and the rear-side stop plate 51 can maintain the standing state of the solid line, and lowering of the tip is prohibited (prevented). When the platform 5 is lowered and the platform's own weight acts and the landing roller 57 is pushed on the ground, the landing detection plate 55 rotates counterclockwise, and the pin 58 engages the left end of the substantially V-shaped engagement hole 53. It moves to the right direction after being disengaged from the stop portion, and is in a prone state in which the front end of the rear wheel stopper plate 51 is lowered as shown by the imaginary line in FIG. That is, platform 5
At the landing position, the rear-side stop plate 51 is automatically turned down, and it is possible to move from the ground, such as a wheelchair or a bogie, onto the platform 5 or from the platform 5 to the ground. In the non-landing state of the platform 5, the rear wheel stopper plate 51 is always kept in an upright state, and its tip is prohibited from lowering, so that a wheelchair or a bogie is securely prevented from falling from the rear edge of the platform 5. .

The operation in which the platform 5 expands horizontally from the closed state in which the platform 5 rises substantially vertically to the open state and the operation in which the platform 5 is stored almost vertically from the horizontal ascending position of the platform and closed to the closed state are automated. To do
An automatic opening / closing mechanism 70 is provided. As shown in FIGS. 4 to 7, the automatic opening / closing mechanism 70
First and second opening / closing links 71 connected between an extension 78 extending forward (to the front as viewed from the vehicle) and a middle position of the side frame 4 with respect to a pivot point of the side frame 4. , 72, and an opening / closing operation member 75 having an opening / closing inclined surface 75a fixed to the lower arm 3. That is, the first and second opening / closing links 71 and 72 constituting the two-link mechanism are pivotally connected to each other by the pin 73, and the roller 74 as a contact member that comes into contact with the opening / closing inclined surface 75a is connected to the pin 73. It is pivoted at. The upper end of the first opening / closing link 71 is pivotally connected to the intermediate position of the side frame 4 with a pin 76,
The lower end of the second opening / closing link 72 is provided with a pin 7
It is pivoted at 7. The opening / closing member 75 includes a triangular plate-shaped portion having the opening / closing inclined surface 75a, and a substantially U-shaped portion which is continuous with the triangular plate-shaped portion toward the base end direction of the lower arm 3. The inside of this substantially U-shaped portion forms an engaging groove 75b that is continuous with the end of the opening / closing inclined surface 75a.

Further, a manual lock mechanism 80 is provided as shown in FIG. 4 to lock the platform 5 in a closed state in which it is stored substantially vertically. This manual locking mechanism 80
Has a lock pin 85 provided so as to protrude from the side surface of the platform 5, and a lock handle 82 having a lock groove 81 fitted into the lock pin 85 from above, and the lock handle 82 is pivotally attached to the side frame 4. Have been. When the lock groove 81 is fitted in the lock pin 85, the lock state continues by the weight of the lock handle 82. To release the lock, the lock handle 82 may be lifted by hand to disengage the lock pin 85 from the lock groove 81 as shown by the imaginary line L in FIG.

In order to define the vertical rising position of the platform 5, a rising stopper 90 is fixed to the platform 5 and protrudes from the side surface of the platform 5. When the platform 5 is vertically raised, the stopper 90 contacts the outer surface of the side frame 4 (the rear surface when viewed from the front of the vehicle). Further, a coil spring 91 is fixed to an inner surface of the side frame 4 facing the lower arm 3 to reduce an impact when the platform 5 is vertically raised. The coil spring 91 abuts on the lower arm 3 at the end of the vertical rising operation of the platform 5 to suppress the movement of the side frame 4 and the platform 5 to reduce the impact.

In the above configuration, when the lifting and lowering of a wheelchair or a trolley, etc., or other cargo handling is not performed, the upper arm 2 and the lower arm 3 are substantially upright by the hydraulic cylinder 6 of FIG. 4 as shown by the solid line P in FIG. And platform 5
Are raised almost vertically, and the platform 5 is fixed to the side frame 4 by the manual lock mechanism 80. Also,
At this time, as in the side frame 4 at the position P in FIG.
The side frame 4 is fitted into the engagement groove 75b of the U-shaped portion from above, and is supported so as not to lower with respect to the lower arm 3. Therefore, even if the hydraulic oil of the hydraulic cylinder 6 leaks, the side frame 4 and the platform 5 do not descend. In this state, the entire lifting device is retracted into the van-type vehicle 10.

When lifting and lowering a wheelchair or a trolley, etc., using the platform 5, the lock handle 82 of the manual lock mechanism 80 shown in FIG. Remove from 85. When the hydraulic cylinder 6 is in the contracted state, the upper arm 2 and the lower arm 3 are rotated clockwise in FIG. 1 by the weight of the side frame 4 and the platform 5, and the roller 74 of the automatic opening / closing mechanism 70 is opened / closed. By raising the opening / closing inclined surface 75a of the member 75, the platform 5 is gradually expanded horizontally from the substantially vertical closed state to the open state of the imaginary line Q in FIGS. 2
As the opening angles of the opening / closing links 71 and 72 are reduced, the platform 5 is deployed horizontally). Platform 5
Is in the open state at the ascending limit position, the retracting operation of the hydraulic cylinder 6 is temporarily stopped, and the platform 5 is stopped at the ascending limit position, that is, at substantially the same height as the floor surface 10a of the van type vehicle 10 (FIG. 1, virtual line Q in FIG. 3). At this time,
As shown in the side frame at the position Q in FIG. 4, the small diameter portion of the cam plate 34 for raising and lowering the front brace plate of the automatic undulating mechanism 30 of the front brace plate is in contact with the roller 35 as a cam follower, so that the front brace plate 31 is substantially horizontal. And the floor 5a of the vehicle and the platform 5
Wheelchairs, trolleys, etc. can be transferred between them. In addition,
The triangular landing detection plate 55 of the automatic raising / lowering mechanism 50 of the rear wheel stopper plate is in the lowered state in FIG. 9, and the rear wheel stopper plate 51 is automatically locked in the upright state as shown by the solid line in FIG. Wheelchairs, bogies, etc. from the edge are securely prevented from falling.

Further, the platform 5 can be lowered from the upper limit position of the virtual line Q in FIGS. 1 and 3 to the landing position in the solid line R in FIG. At the time of this elevating operation, the platform 5 mounted on the side frame 4 always keeps its horizontal level because the upper arm 2 and the lower arm 3 form a parallel link. Between the position where the platform 5 is slightly lowered from the ascending limit position and the landing position, as shown in the side frames 4 at the positions R1 and R2 in FIGS.
The large-diameter portion of the cam plate 34 for raising and lowering the front brace plate comes into contact with the roller 35 as a cam follower, and the front brace plate 31 is held in an upright state to ensure that a wheelchair, a bogie or the like falls from the front edge of the platform. To prevent. In addition, the landing detection plate 55 of the automatic undulation mechanism 50 of the rear brace plate
Since the vehicle has continued to be lowered just before landing of the platform 5, the rear wheel stopper plate 51 maintains the standing state until just before landing, so that it is possible to reliably prevent a wheelchair or a bogie from falling from the rear edge of the platform. it can.

When the platform 5 has completely landed as shown by the solid line R in FIG. 3, the landing roller 57 shown in FIG.
9 hits the ground, and the lower end of the landing detection plate 55 is lifted, so that the rear wheel stopper plate 51 changes to a prone state as shown by the imaginary line in FIG. 9, and the wheelchair, the bogie, etc. can be moved to the ground. Conversely, the rear wheel stopper plate 5 in a state in which a wheelchair, a trolley, and the like to be transferred into the van-type vehicle 10 are laid down from the ground.
1 can be placed on the platform 5. In addition, even when the platform 5 is in a landing state, the front-side vehicle stop plate 31 is kept upright.

After a wheelchair, a trolley and the like on the ground are placed on the platform 5, the hydraulic cylinder 6 shown in FIG. 4 is extended, and the upper arm 2 and the lower arm 3 are rotated counterclockwise to thereby move the platform 5 to the vehicle floor 10a. Can be raised to the ascending limit position (the imaginary line Q in FIGS. 1 and 3) which is a height substantially corresponding to. When the platform 5 starts to ascend from the landing position, the rear-side stop plate 51 returns to the upright state, and thereafter, the rear-side stop plate 51 is held in the upright state.
In addition, the front-side stop plate 31 that has been standing up when the platform is in the landing state is upright because the large-diameter portion of the front-side stop plate up-and-down cam plate 34 is in contact with the roller 35 as a cam follower until immediately before the platform 5 reaches the ascending limit position. Kept in state. Thereafter, when the platform 5 reaches the upper limit position, the small diameter portion of the cam plate 34 for raising and lowering the front brace plate comes into contact with the roller 35 like the side frame 4 at the position Q in FIG. 4, and the front brace plate 31 is in a substantially horizontal state. And the wheelchair, trolley, etc. on the platform 5
0a.

When the hydraulic cylinder 6 is further extended from the upper limit position of the platform 5, as shown in FIG. 4, the rollers 74 provided at the connecting contacts of the first and second opening / closing links 71, 72 of the automatic opening / closing mechanism 70 as shown in FIG. Abuts on the triangular plate-shaped portion of the opening / closing member 75, and the roller 74 gradually descends on the opening / closing inclined surface 75a (moves in the base end direction of the opening / closing member 75). As a result, the roller 74
, The extension portion 78 of the platform 5 is pushed down via the second opening / closing link 72, and the pivot point (pin 15) of the platform 5 with respect to the side frame 4
The platform 5 is rotated counterclockwise around the rotation center. Then, the closing operation of the platform 5 ends when the platform-integrated start-up stopper 90 abuts against the side frame 4 and the platform 5 rises substantially vertically. At this time, the roller 74
Fits into the engagement groove 75b of the substantially U-shaped portion under the opening / closing member 75 down the opening / closing inclined surface 75a. Then, the platform 5 is locked in a closed state by lowering the lock handle 82 of the manual lock mechanism 80 and locking the platform side lock pin 85.

According to this embodiment, the following effects can be obtained.

(1) Between the extension 78 extending forward (when viewed from the front side of the vehicle) and the intermediate position of the side frame 4 from the pivot point (pin 15) of the platform 5 to the side frame 4 The two-link mechanism (first and second opening / closing links 71, 72) is connected, and an opening / closing member 75 having an opening / closing inclined surface 75a is provided on the lower arm 3, and the first and second opening / closing members are provided. A roller 74 as a contact member provided at an intermediate portion (connection portion) of the links 71 and 72 is brought into contact with the opening / closing inclined surface 75a to automatically open and close the platform 5 with the rotation of the upper arm 2 and the lower arm 3. be able to.

(2) The opening / closing member 75 fixed to the lower arm 3 is provided with an engaging groove 7 continuous with the end of the opening / closing inclined surface 75a.
5b, the rollers 74 enter the engagement grooves 75b when the platform 5 is closed, and the platform 5 is securely closed by locking the platform 5 to the side frame 4 by the manual lock mechanism 80. Can be locked to state. In this state, even if the hydraulic pressure to the hydraulic cylinder 6 leaks, the side frame 4 is prevented from lowering and the platform 5 is prevented from opening.

(3) A front-side stop plate undulating cam plate 34 is fixed to the end of the lower arm 3, and a stop-side undulating link mechanism (a bell crank 36, a connecting link) having a roller 35 as a cam follower operated by the cam plate 34. 37) is provided between the side frame 4 and the front brace plate 31, so that the front brace plate 31 can be held (locked) in an upright state during the elevating operation of the platform 5. In addition, the rear-side stop plate 51 is always held (locked) in an upright state by the automatic up-down mechanism 50 when the platform 5 is not landing. For this reason, a fall accident of a wheelchair, a trolley, etc. can be reliably prevented, and safety can be sufficiently ensured.

(4) Opening and closing operation of the platform 5;
Since the undulations of the front and rear stop plates 31 and 51 are all performed automatically, operability is good, and danger due to erroneous operation can be prevented, and safety can be further improved.

The hydraulic cylinder 6 has a structure in which it expands and contracts while rotating with the rotation of the upper arm 2 and the lower arm 3 in order to reduce the installation space.
In principle, a structure may be employed in which either the upper arm 2 or the lower arm 3 is fixedly installed on the vehicle side and driven to rotate, or may be a single-acting or double-acting cylinder.

Although the embodiments of the present invention have been described above, it is obvious to those skilled in the art that the present invention is not limited to the embodiments and that various modifications and changes can be made within the scope of the claims. There will be.

[0038]

As described above, according to the elevating device according to the present invention, the opening and closing operation of the platform and the undulating operation of the front and rear baffle plates are automated, thereby improving operability and safety. be able to.

[Brief description of the drawings]

FIG. 1 is a side view of a general configuration of an embodiment of a lifting device according to the present invention, in which a side frame portion is sectioned.

FIG. 2 is a front view of the lifting device as viewed from a rear surface of the vehicle.

FIG. 3 is a side view showing a state where the platform lands.

FIG. 4 is a side sectional view of a main part for explaining an automatic opening / closing operation of a platform and an undulating operation of a front brace plate.

FIG. 5 is a cross-sectional side view of a main part, illustrating an up-and-down operation of a front brace plate while the platform is being lifted and lowered.

FIG. 6 is a side sectional view of a side frame.

FIG. 7 is a front sectional view of the same.

FIG. 8 is a bottom view showing the rear wheel stopper plate and its automatic undulating mechanism.

FIG. 9 is a side sectional view of an automatic undulating mechanism of a rear-side stop plate.

FIG. 10 is a bottom view of the same.

[Description of Signs] 1 Base box 2 Upper arm 3 Lower arm 4 Side frame 5 Platform 6 Hydraulic cylinder 10 Van type car 10a Floor surface 20, 21 Handrail member 30 Automatic undulating mechanism of front brace plate 31 Front brace plate 34 For raising and lowering front brace plate Cam plate 35 Roller 36 Bell crank 37 Connecting link 39 Raising and lowering drive arm 50 Automatic raising and lowering mechanism of rear brace plate 51 Rear brace plate 52 Perforated engagement plate 53 Substantially V-shaped engagement hole 55 Landing detection plate 57 Landing roller 60 Torsion Bar 70 Automatic open / close mechanism 75 Opening / closing operation member 75a Opening / closing inclined surface 75b Engagement groove 80 Manual lock mechanism 81 Lock groove 82 Lock handle 85 Lock pin 90 Startup stopper 91 Coil spring

Claims (4)

(57) [Claims] 1. A parallel link mechanism having an upper arm and a lower arm is provided at an opening of a vehicle, a side frame is pivotally mounted on a distal end side of the upper arm and the lower arm, and a platform is provided at a lower end of the side frame from a horizontal open state to a substantially vertical state. A lifting and lowering device which is pivotally connected to be openable and closable in a closed state, and is provided with a cylinder for rotating the parallel link mechanism to drive the side frame and the platform up and down, wherein a pivotal connection point of the platform to the side frame is provided. A two-link mechanism is connected between an extension extending further forward and an intermediate position of the side frame, and an opening and closing operation member having an opening and closing inclined surface is provided on the lower arm; An opening / closing drive of the platform is performed by bringing an abutment member provided at an intermediate portion of the mechanism into contact with the opening / closing inclined surface. Lifting apparatus according to claim. 2. The opening / closing operation member has a continuous engagement groove at an end of the inclined opening / closing surface, and the contact member enters the engagement groove when the platform is closed. The lifting device according to claim 1, further comprising a lock mechanism that locks the platform in a closed state with respect to the side frame. 3. A side stop frame linking mechanism including a front brace plate movably connected to a front edge of the platform, a cam fixed to a tip of the lower arm, and a cam follower operated by the cam. 3. The elevating device according to claim 1, wherein the elevating device is provided between the front brace plate and the front brace plate, and holds the front brace plate in an upright state during the elevating operation of the platform. 4. A rear-side stop plate is connected to a rear edge of the platform so as to be able to move up and down, and the rear-side stop plate is held upright by an up-and-down drive mechanism when the platform is in a non-landing state. The lifting device according to 1, 2, or 3.