JP3134849B2 - Simple stage - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a simple stage in which a top plate is folded to be movable, and more particularly to a stage suitably used for forming a temporary stage.

[0002]

2. Description of the Related Art A temporary stage called a simple stage is often used in a lecture hall or a hotel dinner show. A simple stage of this type includes a pair of top plates, legs provided at the outer end of each top plate, and casters provided at the inner end of each top plate. The boards are flush with each other at the inner ends, and the legs provided at the outer ends of the tops are grounded to support the tops. It is known that the upper surfaces are turned around an inner end so that the upper surfaces are close to each other, and the casters provided at the inner end of the top plate are movable on the ground.

[0003]

However, since such a structure has a structure in which the upper surfaces of the top plates are closely opposed to each other, by operating one of the top plates, the other top plate is also symmetrically synchronized. It is structurally difficult to provide a synchronous mechanism that moves in a position below the top plate. Therefore, the top plate must be rotated one by one to operate between the use position and the folding position, and there is a problem that the handling is complicated and troublesome.

[0004] On the other hand, in the field of tables, a pair of top plates is used in a position where the inner ends are brought into contact with each other to be flush with each other.
2. Description of the Related Art There is known an apparatus which can be unfolded and folded in a synchronized manner between a standing position and a folding position in which the bottom faces are closely opposed to each other. In this type, a caster support is provided which extends outward from the middle of the column supporting the top plate, bends downward on the way, and has a caster attached to the lower end thereof. Then, in the use position, the grounding body attached to the tip of the pillar is grounded and the caster is separated from the floor surface, and in the folded position, the caster is grounded and the grounded body is slightly separated from the floor surface, The strut is slightly rotated with the unfolding and folding operation of the top plate, and the standing angle is adjusted.

However, when such a configuration is applied to a simple stage as it is, the grounding member can be slightly separated from the floor surface at the folding position. There is a risk that the robot may not be able to move because it is caught on the hair. In particular, a very heavy object such as a simple stage is difficult to lift, so that it is very difficult to take measures in such a case.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention comprises a top plate connecting mechanism capable of synchronously rotating a top plate, and disturbs a caster from its ability to move over obstacles. To the extent that it does not collapse, the top plate is protruded along with the folding operation, simplifying the deployment and folding operation of the top plate, and hindering movement to some unevenness and obstacles on the floor surface It is intended to provide a simple stage that is not performed.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS That is, in the simple stage according to the present invention, a pair of top plates, the use positions where the inner ends of these top plates abut or come close to each other and are flush with each other, and the bottom surfaces thereof are connected to each other. A top plate coupling mechanism that allows each top plate to be unfolded and folded in synchronization between folding positions standing upright in a state of being opposed to each other, and a top plate that is provided on each top plate and that touches the floor surface at least at the use position and A supporting leg for supporting the plate, a leg pivotally supported by each top plate and provided with a caster at a rotating end, and a leg for rotating the leg as the top plate is unfolded and folded. A drive mechanism, wherein the leg drive mechanism separates the caster from the floor surface in the use position, grounds the caster to the floor surface in the folded position, and moves the caster outside the support leg or the top plate. Rotate the leg so that one end is located above the center of the caster wheel And characterized in that for.

[0008] In such a case, since the top plate connecting mechanism can operate the respective top plates in synchronization, it is possible to link the other top plate simply by moving one of the top plates. Become. Further, the leg drive mechanism automatically switches the support legs in the use position and the casters in the folding position to support the top plate. Therefore, the handling is simple, and the installation or moving operation is very easy. In addition, since the outer ends of the support legs or the top plate are located above the center of the wheels of the casters at the folding position, the outer ends of the support legs or the top plate do not hinder the movement operation by the casters. In other words, the caster can sufficiently exercise its ability to overcome obstacles and the like,
Movement can be performed smoothly.

In order to improve the appearance at the use position and obtain a large-area stage by laying down a simple stage, or to attach a curtain plate to the outer edge of the top plate at the use position, a leg drive mechanism is required. However, it is preferable that the leg is positioned inward from the outer end of the top plate in the use position. In order to configure the top plate connecting mechanism very easily, it is preferable that the top plate connecting mechanism pivotally connects the inner ends of the top plates to each other.

As a specific embodiment of the leg driving mechanism, one end is pivotally connected to each top plate and the inner end of each top plate, and the other end is pivotally connected to each other. A pair of inner link members, and a pair of lower link members each having one end pivotally connected to the other end of each inner link member. And those connected to the department.

In order to secure the self-standing stability at the folding position with a simple structure, the ground contact point of the caster at the folding position with respect to the floor is located outside the pivot point of the leg with respect to the top plate. It is desirable to set it to As a specific embodiment of the leg, a first leg having a base end pivotally connected to the outer end of the top plate and a rotation end pivotally connected to the outer end of the lower link member is provided. An element, a second leg element bent outward from the pivotal end of the first leg element, and a caster attached to the tip of the second leg element. Is mentioned.

In order to improve the load strength at the use position while suppressing the number of parts used, an intermediate support leg is formed by hanging the lower end of the inner link member, and the intermediate support leg is supported at the use position. It is preferable to be configured so that it can be grounded to the floor together with the legs. In order to improve the operation smoothness of the caster during the unfolding and folding operation until the caster touches the ground, the supporting leg should be provided with a rolling element or a sliding element at the outer edge of the tip. It is suitable.

In order to be able to select a suitable height of the simple stage according to the installation location, it is desirable to provide a height adjusting mechanism capable of setting a plurality of top plate heights at the use position. As a specific embodiment of the height adjustment mechanism, the second support leg provided on the top plate and longer than the support leg may be stored in a posture along the top plate and a posture vertical to the top plate. And an upright posture.

In order to facilitate the folding and unfolding operations and to improve the usability, it is preferable to provide an urging mechanism for urging each top plate in the direction of the folding position.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. As shown in FIGS. 1 and 3, the simple stage according to the present embodiment includes a pair of top plates 1 and these top plates 1.
Use position P which is flush with the inner ends 1a
2 and 4, a top plate connecting mechanism 9 that can be unfolded and folded in synchronization with a folding position Q that is erected as shown in FIGS. A support leg 2 suspended from a bottom outer end of the bottom plate, a leg 3 pivotally supported by a bottom outer end of each top plate 1 and provided with a caster 31 at a rotation end,
A leg drive mechanism 4 for rotating the legs 2 in accordance with the unfolding and folding operations of the top 1 and a biasing mechanism 8 for biasing each top 1 in a direction to be folded. are doing.

The top plate 1 has a rectangular plate shape, and includes a top plate main body 11 and a top plate frame 12 made of a square pipe disposed vertically and horizontally on the bottom surface in the left-right direction and the depth direction. The top plate connecting mechanism 9 includes a hinge 91 that pivotally connects the inner ends of the top plates 1 to each other. In the present embodiment, the hinges 91 are provided at two positions on the bottom surface of the top plate main body 11, that is, a front portion and a rear portion.

As shown in FIGS. 5 and 6, the leg 3 has a first leg element 32 composed of a pair of long plate-like members arranged with face plates facing each other, and a second leg in the form of a face plate. The body element 33 is vertically extended so as to extend outward, is formed to have an L-shape in side view, and the caster 31 is attached to the extension end of the second leg element 33. It is. Thus, the base end of the first leg element 32 is pivotally connected to the bracket 7 attached to the bottom outer end of the top plate 1. The caster 31 is of a swingable type.

The leg drive mechanism 4 is constructed by applying a four-sided link structure. As shown in FIGS. 3 and 4, each of the top plates 1 also functioning as a link member, and a pair of inner members. It comprises a link member 41 and a pair of lower link members 42. In the present embodiment, the leg driving mechanism 4 is provided at two positions, a front edge and a rear edge of the top plate 1.

Each part of the leg driving mechanism 4 will be described in detail. The inner link member 41 has a long plate shape, and one end thereof is formed along the front edge and the rear edge of the top plate body 11. The top plate frame 12 is pivotally connected to a position deviated outward from the inner end by a predetermined distance from the inner end, and the other end is connected to the other end of the other inner link member 41. In the present embodiment, the intermediate support leg 5 is bent slightly from one of the inner link members 41 to extend downward integrally therewith, and an intermediate grounding body 51 is provided at the tip thereof. The intermediate grounding body 51 is configured to be grounded. The lower link member 42 is a long plate that is disposed below the top plate frame 12, and the inner end of the lower link member 42 is connected to the inner link member 4.
1 at the lower end. The outer end of the lower link member 42 is pivotally connected to the pivotal end of the first leg element 32 of the leg 3 so that the top plate 1 and the inner link member 4
1, the lower link member 42 and the leg 3 form a four-sided link structure, and the leg 3 is moved to the use position P by utilizing the deformation of the four-sided link structure accompanying the unfolding and folding operation of the top plate 1.
Is set so as to be stored inward from the outer end 1b of the top 1 and to be projected outward from the outer end 1b of the top 1 at the folding position Q.

The support leg 2 is made of a square pipe as shown in FIGS. 5 and 6, and has a bottom surface at the outer end of a top plate frame 12 disposed along the front and rear edges of the top plate body 11. Is installed vertically by welding or the like. A roller 21 serving as a rolling element is axially mounted on the bottom of the support leg 2 on the outer side, with a part of the roller 21 projecting outward. 22 is attached. The protrusion of the grounding body 22 is set slightly longer than the protrusion of the roller 21.

The urging mechanism 8 includes a hinge 91 as shown in FIG.
A coil spring (not shown) mounted on the top plate and exerting an elastic biasing force in a direction in which the top plate 1 is to be folded;
2 and a gas spring 81 whose ends are pivotally connected to a portion displaced inward from the pivot position of the first leg element 32 with respect to the top plate 1. . The gas spring 81 also performs a damper function, and is set so as to exert an urging force in a direction in which the top plate 1 is to be folded like the coil spring. The urging mechanism 8 assists the operating force when the top 1 is raised at the folding position Q, and releases the top 1 even if the hand is released during the unfolding or folding operation.
Plays a role in preventing sudden dropping toward the use position P. The urging force is set to such an extent that the top 1 does not naturally lift at the use position P.

With reference to FIGS. 3, 4 and 7, the operation of each part associated with the folding and unfolding operation of the simple stage according to the present embodiment will be described below. First, at the use position P shown in FIG.
Are standing upright on the floor surface and the grounding body 32 is grounded, and supports the top board 1 together with the intermediate support legs 5.

Next, when an operation such as lifting the inner end 1a of the top plate 1 is performed, since the inner ends of the top plate 1 are pivotally connected to each other by the hinge 91, the top plate 1 is symmetrical. It turns in the direction in which the bottom surfaces face each other and starts to stand. The intermediate supporting leg 5 is immediately separated from the floor surface by the lifting operation, and the supporting leg 2 is inclined so that the lower end thereof moves inward in accordance with the inclination of the top plate 1. By this movement, the grounding body 22 of the support leg 2 is separated from the floor surface and the roller 21 is grounded, and the roller 21 rolls on the floor surface to ensure a smooth folding operation. On the other hand, along with this folding operation, the lower end pivot point of each inner link member 41 approaches the top plate 1 and moves toward the outer end of the top plate 1. By this operation, the lower link member 42 also moves toward the outer end with respect to the top plate 1, and as a result, the leg 2, which is pivotally connected to the lower link member 42, has the caster 31. Is rotated in the direction of moving the top plate 1 to the outer end side.

When the folding operation is further continued, the inclination of the support leg 2 increases, and the leg 3 rotates, and when the top plate 1 is at an angle as shown in FIG. Connect to ground. Thereafter, the support legs 2 are separated from the floor surface, and only the casters 31 are grounded. Then, at the folding position Q, the first leg element 32 stands upright in a vertical state, and the top plate 1 and the like are supported by the casters 31, so that the floor surface can be moved. At the folding position Q, the outer end 1b of the top plate 1 and the support leg 2 are located above the wheel center C of the caster 31.

At the folding position Q, as shown in FIG. 4, the ground contact point X1 on the floor of the leg 3 is more outward than the pivot point X2 on the top plate 1 of the leg 3. At the folding position Q, the load of the top plate 1 and the like is
This acts as a moment for rotating the casters 31 outward. Since this moment is converted into a force in the direction of bringing the top boards 1 closer to each other via the leg driving mechanism 4, it is possible to prevent the top board 1 from expanding to the use position P by its own weight, and to use a special component. At least, the independence stability at the folding position Q can be ensured. Reference numeral R in FIG. 2 denotes a deployment prevention bracket that is detachably mounted between the support legs 2 so that the top plate is not deployed by an unexpected external force. On the other hand, the urging mechanism 8
In order to bring the top plates 1 closer to each other, the first leg element 32 is brought into contact with the stopper S provided on the bracket 7 as shown in FIGS. The leg 3 is prevented from further turning outward, and the top plate 1
It prevents further proximity of each other.

In the unfolding operation from the folding position Q to the use position P, the reverse operation is performed. in this way,
According to the present embodiment, the respective top plates 1 are symmetrically linked to each other, and the support leg 2 is automatically moved by the leg driving mechanism 4 at the use position P, and the casters 31 are moved at the folding position Q. The top plate 1 is replaced to support it. Therefore, the use position P and the folding position Q can be switched by a single operation such as lifting the inner end 1a of the top plate 1, and the installation or moving operation becomes very easy. Moreover, since the outer ends of the support leg 2 and the top plate 1 are located above the center C of the caster 31 at the folding position Q, the caster 31 can move smoothly without obstructing the ability to get over obstacles. become. In the use position P, since the leg 3 is stored inside the outer end of the top 1, all members such as the leg 3 and the top synchronization mechanism 2 are located below the top 1. As a result, it is possible to easily form a large-area stage by laying down a plurality of simple tables without gaps, and to attach a curtain plate to the outer edge of the top plate 1.

In the present embodiment, a height adjusting mechanism 10 is further provided so that the height of the top plate at the use position can be set in two stages. The height adjustment mechanism 10 is provided at the outer end of the top plate 1 and is longer than the support legs 2.
2 is configured to be able to be selected from either a storage posture in which the posture is along the top plate 1 or a standing posture in which the posture is vertical to the top plate. Further, in order to assist the second support leg 102, a second intermediate support leg 105 is provided at an inner end of the top frame 12.

As shown in FIGS. 9 and 10, the second support leg 102 is made of a square pipe having a roller 121 and a grounding member 122 provided at the tip thereof in the same positional relationship as the support leg 2. The base end is pivotally connected to a bracket 123 provided at the outer end of the bottom surface of each top plate 1. Thus, the bendable fixing means 124 is linearly formed as a push rod to maintain the standing position, and the fixing means 124 is bent so that the second support leg 102 can be in the retracted posture.

FIGS. 11 and 12 show the second intermediate support leg 105.
As shown in the figure, the pair of intermediate leg elements 152 and 153 which are open in opposite directions and can be superimposed are connected to each other at one end thereof, and a grounding member 151 is provided below the connection point.
Is arranged. Thus, one middle leg element 152 has its other end pivotally connected to the top frame 12 of one top plate 1 via the bracket 154. The other middle leg element 153 is provided with an engagement groove 156 and a lock claw 157 at the other end, and the engagement groove 156 and the lock claw 157 are attached to a bracket 155 attached to the top plate frame 12 of the other top plate 1. And a lock pawl 157 so as to be detachably pivotable. Specifically, a pin 158 is provided on the bracket 155, and the engaging groove 156 is hooked on the pin 158, and the locking claw 157 is fixed to the pin 1 so as to close the opening of the hooked engaging groove 156.
58 so that it will not come off unless the lock is released. On the other hand, a similar pin 159 is provided on the bracket 154 so that the middle leg element 1 can be used when not in use.
The engagement groove 156 and the lock claw 157 of the 53 are engaged with the pin 159 so that the intermediate leg elements 152 and 153 overlap each other,
It can be stored along one of the top plate frames 12. The superposed intermediate leg elements 152, 15
Reference numeral 3 indicates that the rotating end can be temporarily fixed to the top plate frame 12 by a magic tape or the like so that the rotating member cannot be rotated.

In order to actually increase the height of the top board 1, the second support leg 1 is required to be folded at the folding position Q as shown in FIG.
02 in the standing position, and the second intermediate support leg 105
The other intermediate leg element 153 is pivotally connected to the bracket 155. When the top 1 is unfolded toward the use position in this state, the casters 31 are retracted inward of the top 1 as the top 1 is deployed, and the second
The roller 121 of the support leg 102 is grounded. After that, the casters 31 separate from the floor surface and the second support legs 1
02 gradually erects while rolling the roller 121, and at the use position P shown in FIG.
With the second intermediate support leg 105 and the top plate 1
Will be supported.

In the folding operation from the use position P to the folding position Q, the reverse operation is performed. As described above, in the present embodiment, the height of the top plate 1 can be changed in two stages without impairing the operability for unfolding and folding the top plate 1. Furthermore, if the second support leg 105 and the second intermediate support leg 105 having various lengths are prepared, a simple table corresponding to a required height can be supplied.

The present invention is not limited only to the above-described embodiment. For example, the leg is not limited to the above-described shape, and the leg driving mechanism is not limited to the one using the link structure, but may be any functionally equivalent. Further, a folding lock mechanism or the like which can inhibit the folding operation of the top plate at the use position may be provided. In addition, the configuration of each unit is not limited to the illustrated example, and various modifications can be made without departing from the spirit of the present invention.

[0033]

As described above, according to the present invention,
Since the top plate connecting mechanism can operate each of the top plates in synchronization, it is possible to link the other top plates simply by moving one of the top plates. Further, the leg drive mechanism automatically switches the support legs in the use position and the casters in the folding position to support the top plate. Therefore, the handling is simple, and the installation or moving operation is very easy. In addition, since the outer ends of the support legs or the top plate are located above the center of the wheels of the casters at the folding position, the outer ends of the support legs or the top plate do not hinder the movement operation by the casters. That is, the ability of the caster to overcome obstacles and the like can be sufficiently exhibited, and the movement can be performed smoothly.

If the leg drive mechanism positions the leg inside the outer end of the top plate at the use position, the appearance at the use position is improved without the leg projecting from the top plate. In addition, it is possible to easily obtain a stage having a large area by laying down a simple stage, and to easily attach a curtain plate to an outer edge of a top plate at a use position. If the top plate connecting mechanism connects the inner ends of the top plates to each other, the top plate connecting mechanism can be configured very easily.

A leg drive mechanism includes a pair of inner link members each having one end pivotally connected to the inner end of each top plate and the other end pivotally connected to each other. A pair of lower link members each having one end pivotally connected to the other end of each inner link member, and the other end of each lower link member being pivotally connected to a rotating end of the leg. With this configuration, a leg driving mechanism can be realized with a simple configuration using a four-sided link structure.

If the caster at the folding position is set so that the ground contact point on the floor surface is located outside the pivot point of the leg with respect to the top plate, the top plate or the like at the folding position is set. The load acts as a moment to rotate the caster outward. This moment is converted into a force in the direction of bringing the top plates closer to each other via the leg drive mechanism, so that the top plate can be prevented from expanding to the use position by its own weight, and can be folded without using dedicated parts. Independence stability at the tatami mat position can be ensured.

A first leg element having a base end pivotally connected to the outer end of the top plate and a rotation end pivotally connected to the outer end of the lower link member; If it is provided with a second leg element bent outward from the rotation end of the first leg element and a caster attached to the tip of the second leg element, A leg that can maintain the self-standing stability at the folding position can be easily realized with a reasonable structure.

If the lower end of the inner link member is hung down to form an intermediate support leg, and if the intermediate support leg is configured to be able to contact the floor with the support leg at the position of use, a component The load strength at the use position can be reasonably improved while suppressing the number of use points. If the supporting leg is provided with a rolling element or a sliding body at the outer edge of the tip, the rolling element or the sliding body comes into contact with the floor surface during deployment and folding operation. Operational smoothness can be ensured.

If a height adjusting mechanism capable of setting a plurality of top plate heights at the use position is provided, a suitable height of the simple stage can be selected according to the installation location, thereby improving usability. it can. Specifically, the height adjustment mechanism is provided on the top plate and the second support leg longer than the support leg,
There is a configuration configured to be able to select between a storage posture in which the posture is along the top plate and a standing posture in which the posture is vertical to the top plate.

If the top plate is provided with a biasing mechanism for biasing each top plate in the direction of the folding position, it is possible to reduce the force for the operator to lift the top plate, especially at the time of folding.

[Brief description of the drawings]

FIG. 1 is an overall perspective view showing a simple stage according to an embodiment of the present invention in a use position.

FIG. 2 is an overall perspective view of the simple stage of the embodiment in a folding position.

FIG. 3 is a front view of the simple stage of the embodiment in a use position.

FIG. 4 is a front view of the simple stage of the embodiment at a folding position.

FIG. 5 is a partial perspective view particularly showing a leg at a use position in the embodiment.

FIG. 6 is a partial perspective view particularly showing the leg at the folding position in the embodiment.

FIG. 7 is an exemplary front view showing a state where the simple stage according to the embodiment is located between a folding position and a use position;

FIG. 8 is a partial side view particularly showing the leg of the embodiment.

FIG. 9 is a partial perspective view showing a second support leg of the embodiment.

FIG. 10 is a partial perspective view showing a second support leg of the embodiment.

FIG. 11 is a partial perspective view showing a second intermediate support leg of the embodiment.

FIG. 12 is a partial perspective view showing a second intermediate support leg of the embodiment.

FIG. 13 is an operation explanatory view of the embodiment.

FIG. 14 is an operation explanatory view of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Top plate 1a ... Inner end 1b ... Outer end 2 ... Support leg 21 ... Rolling element (roller) 3 ... Leg 31 ... Caster 32 ... First leg element 33 ... Second leg element 4 ... Leg Drive mechanism 41 ... Inner link member 42 ... Lower link member 5 ... Intermediate support leg 8 ... Biasing mechanism 9 ... Top plate coupling mechanism 10 ... Height adjustment mechanism 102 ... Second support leg P ... Use position Q ... Folding position C … Caster wheel center X1… Grounding point X2… Leg pivot point to the top plate

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) E04H 3/24-3/28 A47B 3/083 A63J 1/00

Claims (11)

(57) [Claims] 1. A position between a pair of top plates, a use position where the inner ends of these top plates abut or come close to each other, and are flush with each other, and a folding position where the bottom surfaces of the top plates stand close to each other. A top plate coupling mechanism that can deploy and fold each top plate in synchronization with
A support leg provided on each top plate for supporting the top plate while being in contact with the floor surface at least at a use position; a leg pivotally supported by each top plate and provided with a caster at a rotating end; A leg driving mechanism for rotating the leg in accordance with the folding operation, wherein the leg driving mechanism separates the caster from the floor surface in the use position, and the leg drive mechanism in the folding position. A simple stage wherein the caster is brought into contact with the floor and the leg is rotated so that the outer ends of the support leg and the top plate are located above the center of the wheel of the caster. 2. A leg driving mechanism for positioning a leg inside an outer end of a top plate in a use position.
Simple stage described. 3. The simple stage according to claim 1, wherein the top plate connecting mechanism pivotally connects the inner ends of the top plates to each other. 4. A pair of inner links formed by a leg drive mechanism having one end pivotally connected to each top plate and the inner end of each top plate, and the other end pivotally connected to each other. A member and a pair of lower link members each having one end pivotally connected to the other end of each inner link member. The other end of each lower link member is pivotally connected to the pivoting end of the leg. 4. The simple stage according to claim 1, wherein the simple stage comprises: 5. The simple stage according to claim 4, wherein the ground contact point on the floor surface of the caster at the folding position is set outside the pivotal connection point of the leg to the top plate. 6. A first leg element having a base end pivotally connected to an outer end of the top plate and a pivot end connected to an outer end of the lower link member. A second leg element bent outward from the pivotal end of the first leg element, and a caster attached to the tip of the second leg element. The simple stage according to claim 4. 7. The intermediate support leg is formed by suspending the lower end of the inner link member so that the intermediate support leg can be grounded to the floor together with the support leg in the use position. Or the simple stage of 6. 8. The supporting leg is provided with a rolling element or a sliding element at the outer edge of the distal end thereof.
The simple stage described in 3, 4, 5, 6 or 7. 9. The apparatus according to claim 1, further comprising a height adjusting mechanism capable of setting a plurality of heights of the top plate at the use position.
The simple stage described in 5, 6, 7 or 8. 10. A height-adjusting mechanism, wherein a second support leg, which is provided on a top plate and is longer than the support leg, is set in a storage position in which the position is along the top plate and a position in which the second support leg is perpendicular to the top plate. The simple stage according to claim 9, wherein the simple stage is configured to be able to select any one of a setting posture and a setting posture. 11. An apparatus according to claim 1, further comprising an urging mechanism for urging each of the top plates in the direction of the folding position.
The simple top plate described in 6, 7, 8, 9 or 10.