JPH11159126A - Safety device for folding type workbench - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decelerate the spreading speed of a scaffolding board in a second half during spreading works without charging a more working burden to an operator. SOLUTION: A scaffolding board 3 as the scaffolding of an operator is rocked between a folding place as an approximately vertical posture and a spreading place as an approximately horizontal posture by utilizing parallel crank mechanisms. A buffer 15 is composed of a hydraulic damper 16 displaying braking force at the time of the forward movement of a rod 30 and releasing braking force at the time of a retreat and a variable speed mechanism 18 consisting of a plurality of arm members 17a, 17b and increasing the quantity of the forward stroke of the hydraulic damper 16 in the second half of a spreading stroke towards the spreading place from the folding place, and the scaffolding board 3 is given braking force in the second half of the spreading stroke by the buffer 15 while braking force is released or reduced in the first half of the spreading stroke and a folding stroke.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved worktable which can be folded and unfolded.

[0002]

2. Description of the Related Art A foldable work table is known as a temporary work floor for performing work such as painting, which can be compactly folded when not in use.

FIG. 6 shows a schematic structure of the folding work table, in which two parallel crank mechanisms (40) are connected to each other, and a scaffold plate (2) serving as an operator's foot is connected to the two parallel crank mechanisms (40). 41) (in the drawing, the case where one link member is a scaffold plate 41 is illustrated), and a moving caster (43) is attached to the lower end of a vertical link member (42). . In use, this workbench is deployed so that the scaffold plate (41) is horizontal as shown in the upper part of the figure, and when not in use, as shown in the lower part of the figure, the scaffold plate (4)
1) is compactly folded so that it is almost vertical. The work of unfolding the workbench is performed by the operator grasping the scaffold plate (41), the frame, and the like, and pressing the scaffold plate (41) in the direction of the arrow in the figure.

[0004]

However, in the latter half of the deployment operation, that is, after the inclination angle of the scaffold plate exceeds approximately 45 °, the influence of gravity increases and the deployment speed of the scaffold plate increases. Therefore, there is a possibility that the worker during the deployment operation may be exposed to danger.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a folding workbench capable of reducing the deployment speed in the latter half of the deployment operation and without imposing an additional work burden on the operator.

[0006]

In order to achieve the above object,
The safety device for a folding workbench according to the present invention has a parallel crank mechanism connecting a scaffold plate serving as a scaffold for an operator, and one link member of the parallel crank mechanism as a fixed link,
A scaffold plate is mounted on a worktable that swings between a substantially vertical folding position and a substantially horizontal deployment position, and applies a braking force to the scaffold plate in the latter half of the deployment process. In addition, a cushioning device is provided for releasing or reducing the braking force in the first half of the expanding stroke and the folding stroke.

The shock absorber has a hydraulic damper pivotally connected to a fixed link, a transmission having an input side connected to any movable link other than the fixed link of the parallel crank mechanism and an output side connected to a rod of the hydraulic damper. And a mechanism.

The hydraulic damper exerts a braking force when the rod advances, and releases the braking force when the rod retreats.

In this case, the speed change mechanism changes the stroke of the hydraulic damper in accordance with a change in the posture of the scaffold, and increases the forward stroke of the hydraulic damper in the latter half of the deployment stroke. Good.

Specifically, the speed change mechanism has a first arm member and a second arm member having one ends pivotally connected, and the other end of the first arm member is connected to a node between the movable links of the parallel crank mechanism. The other end of the second arm member is pivotally connected to the rod of the hydraulic damper, and a portion displaced toward the rod from an intermediate point of the second arm member is pivotally supported by a fixed link.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a perspective view of a foldable work table, and FIG. 2 is a side view thereof. 1 and 2, the shock absorber is not shown.

As shown in FIGS. 1 and 2, the foldable work table is composed of two table units (1) configured to be foldable and expandable.
Are connected and integrated by unit connecting materials (2A) and (2B) arranged vertically. Both units (1)
Has a substantially rectangular shape in plan view, and is composed of a mesh-like scaffold plate (3) that functions as a scaffold for an operator when deployed, and a leg frame (4) that supports the scaffold plate (3).

The leg frame (4) comprises four nested vertical frame members (5a, 5b) each comprising an outer cylinder member (51) and an inner cylinder member (52) slidably inserted into the inner space. Is provided. Each of the vertical frame members (5a, 5b) is vertically suspended at four locations so as to draw a tubular body having a rectangular cross section, and two vertical frame members adjacent to the work table in the width direction (vertical direction in FIG. 2). (5a, 5b) are integrally connected by upper and lower fixed connecting members (6a, 6b) arranged horizontally, respectively. Brackets (7) are provided at both ends of each fixed connecting member (6a, 6b).
Are mounted, and upper and lower movable connecting members (9A, 9B) are erected in a direction orthogonal to the fixed connecting members (6a) (6b) between the opposed brackets (7). Each movable connection material (9A, 9B)
Have the same length, and both ends thereof are rotatably connected to the respective brackets (7) via pins (10). With the above configuration, a four-bar parallel crank mechanism is formed by the upper and lower movable connecting members (9A, 9B) and the vertical frame members (5a, 5b) sandwiching the movable connecting members (9A, 9B) from both sides. In this parallel crank mechanism, a vertical frame member (5a) and a unit connecting member (2A, 2A) on the counterpart base unit side (hereinafter, the direction approaching the counterpart base unit is referred to as inside and the direction away from the base unit is referred to as outside).
B) and the inner fixed connecting member (6a) serve as fixed links.
b, movable connecting members 9A and 9B, outer fixed connecting members 6b, etc.), when the external force is applied, the two vertical surfaces of the leg frame (4) opposed to each other in the left-right direction of the worktable are slid parallel to each other. Then, it is possible to approach / separate while shifting in the vertical direction.

The upper end of the inner cylindrical member (52) of each of the vertical frame members (5a, 5b) faces the inside in the lengthwise direction of the worktable (in FIG. 90 °. In this manner, the bent portions (52a, 52
b) is provided so that it can function as a load receiver,
This is to ensure a certain degree of horizontality of the scaffold plate (3) even when the vertical frame members (5a, 5b) are vertically displaced due to unevenness of the floor surface. Bent part (52a, 52b)
Are pivotally attached to the side surfaces of the scaffold plate (3) via pins (12a, 12b). Both pins (12a, 12b)
The inner pin (12a) is supported by an elongated hole (not shown) provided in the scaffold plate (3) and extending in the length direction of the worktable. The bent portion (52a) is slidable with respect to the scaffold plate (3) in the length direction of the worktable (in the direction in which the distance between the pins 12a and 12b expands and contracts).

At the lower ends of the four vertical frame members (5b) located outside the both unit units (1) and at two places on the bottom surface of the lower unit connecting member (2B), the working table is moved in order. Casters (13) with stoppers are installed.

The both units (1) are provided with a telescopic lifting rod (8) composed of an outer cylinder (81) and an inner cylinder (82) slidably inserted into the inner diameter of the outer cylinder (81). The lifting rod (8) is interposed between the upper unit connecting member (2A) and one upper end of the two inner vertical frame members (5a), and is attached to the counterpart base unit (1). It is arranged so as to intersect with the provided lifting rod (8). The outer cylinder (81) of both lifting rods (8) is connected to the upper unit connecting material (2
A), the upper end of the inner cylinder (82) is
Each of the bent portions (52a) of (a) is rotatably pivoted, and the two pivots at this time extend in the length direction of the worktable. From the above, the lifting rod (8) can be extended and contracted and can swing in a plane orthogonal to the length direction of the worktable.
The elevating rod (8) is provided with a safety mechanism (not shown) for preventing the fall of the scaffold plate (3) when the scaffold plate (3) is raised after the work table is deployed. I have.

The workbench described above allows the operator to grasp the appropriate member, for example, the outer upper or lower fixed connecting member (6b) and push it up or down so that the scaffold plate (3) is substantially moved. It can be in a vertical folding position (indicated by solid lines in FIG. 2) or in a substantially horizontal unfolding position (indicated by broken lines). At the time of unfolding, the leg frame (4) is in an open state, so that it is possible to stably support the worker riding on the scaffold plate (3), and at the time of folding, the vertical frame material (5a, 5b), scaffolding board (3), fixed connecting material (6a, 6b)
Since various members such as the movable connecting members (9A, 9B) and the like can be grouped in a vertically flat shape, compactness can be achieved.

After the work table is deployed, the height of the scaffold plate (3) is adjusted. To raise the scaffold plate (3), lift the scaffold plate (3) upwards and lift each vertical frame material (5a,
5b) and the lifting rod (8) are extended, and when the scaffold plate (3) reaches a predetermined height, each vertical frame member (5a, 5
b) Insert a lock pin into the baffle (at this time, even if the operator releases his hand from the scaffold, the safety mechanism provided on the elevating rod (8) operates to lock the elevating rod (8). (3) does not fall). To lower the scaffold (3), the vertical frame members (5a, 5b)
, Pull down the scaffold plate (3) while releasing the safety mechanism by grasping the lever (not shown),
What is necessary is just to shorten each vertical frame material (5a, 5b) and the raising / lowering rod (8).

By the way, in this type of folding work table, as pointed out in the above-mentioned problem, in the latter half of the unfolding operation, the influence of gravity increases, and the unfolding speed of the scaffold plate (3) increases, and Can be dangerous.
In particular, in the work table shown in FIGS. 1 and 2, as the deployment progresses, the bent portion (52) of the outer vertical frame (5b)
Since the gap (S in FIG. 2) between b) and the scaffold plate (3) gradually narrows, the fingers of the worker may be caught in this part S depending on the working conditions.

In order to solve this problem, in the present invention, as a safety device, a braking force is applied to the scaffold plate (3) in the latter half of the deployment stroke, and the braking force is released or reduced in the first half of the deployment stroke and the folding stroke. And a shock absorbing device.

As shown in FIG. 3, the shock absorber (15) comprises a hydraulic damper (16) and a speed change mechanism (18) in which a plurality of arm members (17a, 17b) are connected. In the drawings, only the shock absorber (15) provided on one base unit (1) is shown, and the illustration of the shock absorber provided on the other base unit (1) is omitted.

The hydraulic damper (16) has its base rotatably pivoted to a fixed link, for example, an inner and lower fixed connecting member (6a), and its structure is as shown in FIG. The hydraulic damper (16) has an inner cylinder (22) that slidably accommodates a piston (21) and an outer cylinder (23) that accommodates the inner cylinder (22). An oil passage (24) is provided between the piston (21) and the outer cylinder (23), and both ends of the oil passage (24) are connected to the oil chambers on both sides of the piston (21) via a rod cover (25) and a head cover (26). (27a, 27b). The oil passage (24) branches into the rod cover (25) and opens into the oil chamber (27a) on the rod side in two systems (one opening is not shown). A flow control valve, such as a valve (28), has a check valve (not shown) for preventing flow from the rod-side oil chamber (27a) to the oil passage (24) and allowing flow in the opposite direction. ) Is provided. (29) is an accumulator arranged between the inner cylinder (22) and the outer cylinder (23).

With the above arrangement, when the piston rod (30) moves forward due to an external load, the oil in the rod-side oil chamber (27a) passes through the needle valve (28), and the head-side oil chamber ( Since it flows into 27b), a braking force acts on the rod (30). On the other hand, when the rod (30) moves backward, the oil in the head-side oil chamber (27b) flows into the rod-side oil chamber (27a) through the check valve, so that the brake force may be released. it can.

The speed change mechanism (18) is composed of a first arm member (17a) and a second arm member (17b) having one ends rotatably connected to each other. The other end (input side) of the first arm member (17a) is an upper pivot of the pivots (nodes) connecting the movable links, specifically, the upper movable connecting member (9).
A) and the pin (1) connecting the outer vertical frame material (5b)
0), and the other end (output side) of the second arm member (17b) is pivotally connected to the tip of the rod (30) of the hydraulic damper (16). The intermediate portion of the second arm member (17b) is pivotally attached to the upper unit connecting member (2A), and the support shaft (19) at that time.
Is the pivot point (31) with the rod (30) rather than the exact midpoint
It is in the position shifted to the side.

With the above structure, each arm member (17a,
17b) is displaced as shown in FIG. 5 in accordance with a change in the posture of the scaffold plate (3) in accordance with the unfolding / folding operation of the work table.
FIG. 5 shows that the operation of deploying the worktable is changed according to the inclination angle of the upper movable connecting member (9A) (the angle about the inner pivot 10).
It is divided into sections (angle change in section A is 18.7 °, B ~
G shows a change in the angle of each section of 15 °), and illustrates the posture of the first arm member (17a) and the second arm member (17b) in each section.

From FIG. 5, the rod (30) of the hydraulic damper (16) moves forward from the folded state (a in the figure) to the deployed state (b in the figure), and the forward stroke at this time is In the first half (63.7 ° of a → c), it is small, but in the second half (45 ° of c → b), it becomes conspicuously large. Assuming that the actual stroke of the hydraulic damper (16) is 191.6 mm, the section A is 0.4 mm, the section B is 6.2 mm, and the section C is 18.
The stroke is 7 mm, 35 mm in section D, 44.6 mm in section E, 45.8 mm in section F, and 40.9 mm in section G. This is because in the first half of the deployment stroke, the forward stroke is small, and therefore the braking force of the hydraulic damper (16) hardly acts, but in the second half, the forward stroke becomes large and the braking force of the hydraulic damper (16) sharply increases. Means that. Therefore, in the first half of the unfolding process (arrow in the figure), the operator can unfold smoothly,
Also, in the latter half when the influence of gravity becomes large, the deployment speed of the scaffold plate (3) is reduced by the braking force to ensure the safety of workers and to reduce the impact when the caster (13) lands. Can be. On the other hand, in the folding stroke (arrow in the figure), the rod (3
0) is retracted, but as described above, when the rod (30) is retracted, the brake force of the hydraulic damper (16) does not act at all, so that it can be smoothly folded with a small amount of labor, and further labor is imposed on the operator. Not even.

In the above description, the transmission mechanism (18)
Although an example using two arm members (17a, 17b) is illustrated, the configuration is arbitrary, and any mechanism that can increase the stroke amount of the hydraulic damper (16) in the latter half of the deployment stroke is used. Can be widely used. The structure of the hydraulic damper (16) is also optional. For example, an air damper other than the hydraulic damper can be used as long as it exhibits the same function.

The starting point of the application of the braking force can be set freely, and may be set to about 45 ° as described above, or may be set to an angle before or after this.

[0030]

As described above, according to the present invention, in the latter half of the deployment stroke, the deployment speed of the scaffold plate is reduced by the braking force of the shock absorber, and the safety of the worker can be ensured. On the other hand, in the other strokes, that is, in the first half of the unfolding stroke and the folding stroke, the worker can smoothly unfold and fold with a small amount of labor, and does not impose a further work labor on the worker.

[Brief description of the drawings]

FIG. 1 is a perspective view of a folding work table.

FIG. 2 is a side view of the folding work table.

FIG. 3 is a side view of a folding workbench having a shock absorber.

FIG. 4 is a sectional view of a hydraulic damper.

FIG. 5 is a side view showing the operation of the transmission mechanism.

FIG. 6 is a conceptual diagram of a folding workbench.

[Explanation of symbols]

 3 Scaffolding plate 15 Shock absorber 16 Hydraulic damper 17a First arm member 17b Second arm member 18 Transmission mechanism 30 Rod

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Kunihiko Takasaki 1-1-1, Kitaeguchi, Higashiyodogawa-ku, Osaka-shi, Osaka Taiyo Iron Works Co., Ltd. (72) Toshiyuki Watanabe 1-chome Kitaeguchi, Higashiyodogawa-ku, Osaka-shi, Osaka No. 1 in Taiyo Tekko Co., Ltd.

Claims (5)

[Claims] A parallel crank mechanism connected to a scaffold plate serving as a scaffold for an operator, wherein one link member of the parallel crank mechanism is used as a fixed link, and the scaffold plate is folded at a substantially vertical folding position. A worktable that swings between a horizontal deployment position and a work platform that applies a braking force to the scaffold plate in the latter half of the deployment stroke from the folding position to the deployment position, and performs the first half of the deployment stroke. And a safety device for a collapsible workbench comprising a shock absorber for releasing or reducing the braking force during the folding stroke from the deployed position to the folded position. 2. A hydraulic damper pivotally connected to a fixed link, an input side pivotally connected to any movable link other than the fixed link of the parallel crank mechanism, and an output side pivotally connected to a rod of the hydraulic damper. 2. The safety device for a folding workbench according to claim 1, wherein the safety device comprises a transmission mechanism. 3. The safety device according to claim 2, wherein the hydraulic damper exerts a braking force when the rod advances, and releases the braking force when the rod retreats. 4. A transmission mechanism for changing a stroke amount of a hydraulic damper according to a change in posture of a scaffold plate,
4. The safety device according to claim 3, wherein the forward stroke of the hydraulic damper is increased in the latter half of the deployment stroke. 5. The speed change mechanism has a first arm member and a second arm member having one ends pivotally connected, and the other end of the first arm member is connected to a node between movable links of the parallel crank mechanism. 5. The device according to claim 4, wherein the other end of the second arm member is pivotally connected to a rod of the hydraulic damper, and a portion displaced toward the rod from an intermediate point of the second arm member is pivotally supported by a fixed link. Safety device for folding workbench.