JP7812673B2 - Workbench - Google Patents

Description

The present invention relates to a workbench, and in particular to a workbench equipped with a base that can be placed on the floor when an operator steps on it and the weight of the workbench increases, and a caster device that supports the base so that it can be moved while being lifted off the floor when no operator is on the workbench and the workbench is at a predetermined weight.

A variety of work platforms are available for workers to use when working at heights, and one known type is one that can be moved along the floor using casters when no worker is on it, but can be placed in a stable, immovable state by resting on the floor when a worker is on it (Patent Document 1). Incidentally, in this specification, the term "work platform" does not limit specific work platforms such as step ladders, stools, or portable work platforms, but should be understood to broadly include any device that provides a foothold for workers to work at a height higher than the floor.

Patent No. 6630954

As shown in Figure 12, for example, the caster device 101 for a workbench proposed in Patent Document 1 has a socket 103 extending in the vertical direction fixed to a fixed member 102 of the workbench, a sliding shaft 104 slidably inserted into the socket 103 and a swiveling wheel 105 attached to the lower end thereof, and magnet means 106 consisting of an abutment and a receiving body that are magnetically attracted to each other between the upper end of the sliding shaft 104 inserted from the socket 103 and the upper end surface of the socket 103; when the workbench is raised, the sliding shaft 104 descends, causing the abutment to be placed in abutment against the receiving body, which is magnetically attracted by the magnet means 106.

According to Patent Document 1, the magnet means 106 supports the weight of the workbench with the contact body placed on the receiving body and magnetically attached to it, and as shown in Figure 12 (A), the wheels 105 of the caster device 101 are rollably grounded on the floor surface with the base 108 provided at the lower end of the column pedestal 107 raised above the floor surface G. Therefore, the workbench is in a "movable state" in which it can be moved by rolling along the floor.

As shown in Figure 12 (B), when a worker steps onto the workbench, the increased weight is received by the socket 103, which releases the magnetically attached state and causes the workbench to descend together with the socket 103, with the leg seat 108 coming into contact with the floor surface G. Although the wheels 105 of the caster device 101 are also in contact with the floor, the contact pressure and frictional force of the leg seat 108 keep the workbench in a stable, "immovable" state so that it does not move on the floor.

At this time, when the worker steps down from the workbench and lifts it to raise the socket 103, the base 108 moves away from the floor and the sliding shaft 104 descends, causing the contact body to rest on the receiving body, and the magnet means 106 becomes magnetically attracted, returning the unit to its original "movable state."

However, unless the worker lifts the work platform (socket), the base remains in contact with the floor, and the work platform is in an "immovable state." Therefore, if the work platform is moved along the floor in this state, the base will be dragged along the floor, which could result in wear and tear or other damage.

In this regard, the "movable state" (when the base is floating) and the "immovable state" (when the base is in contact with the floor) are achieved by the socket and sliding shaft of the caster device sliding up and down relative to each other, but this sliding stroke is short, approximately 10 mm. For this reason, it is not always easy for a worker to determine simply by looking from above whether the base is in contact with the floor, or whether the contact body and receiving body of the caster device are in contact with or separated from each other. As a result, there is a risk that a worker may mistake a "immovable state" for a "movable state" and drag the base across the floor. This could not only damage the base, but also damage the wheel support parts (axle or fork) if the rotation direction of the caster wheel crosses the drag direction.

Generally, workbenches have a total of four pedestals 107 at least at the four corners of the rectangular top, and the caster devices 101 are also attached near each pedestal 107. In other words, a total of four caster devices 101 are positioned near at least the four corners.

Therefore, when a worker steps onto the workbench, if the worker's weight evenly distributes the load across the entire workbench top, the sockets 103 and sliding shafts 104 slide vertically relative to each other between the four caster devices 101 at approximately the same time, allowing the bases 108 of the four pedestals 107 to touch the ground.

However, if a worker stands near the edge of the tabletop, the tabletop will be subjected to an uneven load, which could cause the workbench to tilt. In other words, the caster devices 101 closest to the worker will perform relative sliding between their sockets 103 and sliding axles 104 quickly, but the caster devices 101 further away will perform relative sliding between their sockets 103 and sliding axles 104 later, causing the workbench to tilt in the process.

When the workbench tilts, as shown in Figure 12 (C), the axis V of the socket 103 and sliding shaft 104 of the caster device 101 deviates from the vertical and tilts, which can cause the vertical load W to twist the sliding surfaces of the socket 103 and sliding shaft 104, resulting in damage. Furthermore, in a caster device 101 that has twisted, the socket 103 and sliding shaft 104 are prevented from sliding relative to each other, so the base 108 of the column base 107 located nearby does not come into contact with the ground, and the "immobility state" is not complete, which can pose a risk to work.

Furthermore, the "movable state" is achieved by using the magnet means 106 to prevent the socket 103 and sliding shaft 104 from sliding up and down. Therefore, when applying this to a large workbench, for example, a large magnet means 106 with strong magnetic force is required to withstand the heavy weight.

The objective of the present invention is to provide a workbench that solves the above problems.

The first aspect of the present invention is a workbench of a predetermined weight on which a worker can get on and off, which includes a base that is brought into contact with the floor when the weight of the workbench increases from the predetermined weight due to the worker getting on, and a caster device that movably supports the base while keeping it above the floor when the worker is not on and the workbench is at the predetermined weight. The caster device is attached to a mounting fixture fixed to a predetermined fixed member of the workbench via an arm means, and the arm means includes an arm portion that extends downward from a pivot part that is pivotally supported on the mounting fixture around a horizontal axis, and the caster device is attached to a position near the lower end of the arm portion that is offset from the horizontal axis in the direction of rotation. The arm can be freely changed between an upright position in which the arm is nearly perpendicular to the floor surface and an inclined position in which the arm is rotated sideways. When in the upright position, the caster device is positioned near the fixed member to raise the foot seat off the floor, while when in the inclined position, the caster device is moved sideways to bring the foot seat into contact with the floor. A retaining means is provided to maintain the arm in the upright position. When the workbench is at a predetermined weight, the retaining means maintains the arm in the upright position, but when the weight of the workbench increases, the retaining means allows the arm to be in the inclined position.

Furthermore, the second means of the present invention is a workbench of a predetermined weight on which a worker gets on and off, which is equipped with a foot seat that is brought into contact with the floor surface when the weight increases from the predetermined weight due to the worker getting on, and a caster device that supports the foot seat so that it can be moved while being raised above the floor surface when the worker is not getting on and the workbench is at the predetermined weight, and the caster device includes a mounting bolt that extends in the vertical direction, and a support member that supports a wheel below the mounting bolt at a position offset to the side from the axis of the mounting bolt, The support member is provided with a connecting member that rotatably connects the support member to a mounting bolt, and is attached via arm means to a mounting fixture fixed to a predetermined fixed member of a workbench, the arm means comprising a pivot part that is pivotally supported on the mounting fixture so as to be rotatable about a horizontal axis, an arm part that extends downward from the pivot part, and a mounting part that extends near the lower end of the arm part to a position offset in the rotation direction from the horizontal axis, and a mounting bolt of the caster device is fixed to the mounting part, and the arm means is configured to support the arm part relative to the floor surface. The workbench is capable of being freely changed between an upright position, in which it is nearly vertical, and an inclined position in which the arm portion is rotated in the extension direction of the mounting portion. When in the upright position, the caster device is positioned near the fixed member, thereby lifting the foot seat off the floor. When in the inclined position, the caster device is moved in the extension direction of the mounting portion, thereby bringing the foot seat into contact with the floor. A retaining means is provided to maintain the arm means in the upright position. The retaining means has a retaining force that maintains the arm means in the upright position. When the workbench is at a predetermined weight, the retaining force overcomes the moment generated in the arm means, but when the weight of the workbench increases, the retaining force overcomes the moment generated in the arm means, allowing the arm means to assume an inclined position. When the arm means changes position from the upright position to the inclined position, the mounting portion of the arm tilts the mounting bolt of the caster device, thereby rotating the wheel in the rotation direction of the arm portion.

In a preferred embodiment of the present invention, in a configuration in which the arm portion of the arm means is rotated from an upright position toward the outside of the workbench to an inclined position, stopper means are provided between one of the fixing member and the mounting fixture and the arm means to prevent the arm means from further rotating toward the outside of the workbench from the inclined position when the arm means is in the inclined position.

In a preferred embodiment, the holding means is composed of magnet means that are magnetically attached in abutting contact when the arm means is in an upright position and are separated when the arm means is in an inclined position.

In another embodiment, the holding means is configured as a spring that elastically holds the arm means in an upright position and allows the arm means to assume an inclined position by deforming against the elasticity.

According to the present invention, when a worker steps onto a workbench in a "movable state," even if the workbench is subjected to an unbalanced load, all of the caster devices 8 can be moved sideways appropriately, allowing all of the leg seats 4 to touch the ground at approximately the same time, thereby ensuring work safety. Furthermore, the mechanism for moving the caster devices 8 sideways is composed of arm means 7 that rotates due to the moment generated by the load caused by the worker's weight, so there is no risk of damage, etc.

1 is a perspective view showing a movable state of a workbench according to one embodiment of the present invention, in which the base is lifted off the floor and the wheels of the caster device are in contact with the floor surface so as to be able to roll freely. FIG. FIG. 10 is a perspective view showing the workbench in an immovable state in which the base is in contact with the floor surface and the wheels of the caster device are in contact with the floor surface. FIG. 1 is an exploded perspective view of members and components constituting an embodiment of the present invention. FIG. 10 is a cross-sectional view showing a state in which the arm means is in an upright position. 1A is a side view showing the arm means from outside the workbench in a movable state with the arm means in an upright position, and FIG. 1B is a cross-sectional view of the arm means. The function of the arm means and caster device is shown in cross section, where (A) is a cross section showing the state when the position change from the upright position to the tilted position begins, and (B) is a cross section showing the state when the tilted position is reached. 1A is a cross-sectional view showing the prior art, and FIG. 1B is a cross-sectional view showing an embodiment of the present invention, showing the differences between the prior art and an embodiment of the present invention. 1A shows a stopper means provided at the pivotal support portion of the arm means, where FIG. 1A is a cross-sectional view showing the state when the arm means is in a tilted position, and FIG. 1B is a cross-sectional view showing the state when the arm means is further tilted from the tilted position. 10A and 10B show another embodiment of the magnet means constituting the holding control means, in which (A) is a cross-sectional view showing the state in which the arm means is held in an upright position, and (B) is a cross-sectional view showing the state in which the arm means has rotated toward a tilted position due to the holding being released. 10A shows a spring constituting another embodiment of the holding control means, where (A) is a cross-sectional view showing the state in which the arm means is held in an upright position, and (B) is a cross-sectional view showing the state when the arm means has rotated toward a tilted position against the holding force. 10A and 10B are cross-sectional views illustrating another embodiment for use. 1A and 1B show a conventional technique, in which (A) is a cross-sectional view showing a movable state, (B) is a cross-sectional view showing an immovable state, and (C) is a cross-sectional view showing a problem.

A preferred embodiment of the present invention will be described in detail below with reference to the drawings.

As shown in Figures 1 to 3, the work platform has a top plate 1 on which a worker stands when working at height, supported by column bases 2. Adjacent column bases 2 are connected near their bottom ends by beam members 3, and a base seat 4 is attached to the bottom end of each column base 2.

Although not shown in the figure, the tabletop 1 is made of a rectangular or square metal plate, and at least the areas near the four corners are supported by four pedestals 2. Therefore, in the following explanation, the area surrounded by the pedestals 2 will be referred to as the inside of the workbench, and the area outside this area will be referred to as the outside of the workbench.

The work platform itself is designed to have a predetermined weight, and when a worker sits on it, the weight increases from the predetermined weight.

The workbench has caster devices 8 attached via arm means 7 to mounting fixtures 6 fixed to fixed members 5 formed by the beam members 3. When no worker is on the workbench and the weight is a predetermined value, the caster devices 8 support the workbench movably (movable state) by setting the arm means 7 to an upright position P1 as shown in Figure 1, with the base 4 floating at a position H above the floor G by a predetermined distance. This allows the worker to move the workbench to the desired location by running the caster devices 8 on the floor.

On the other hand, when the weight of the workbench increases from a predetermined weight due to a worker getting on, the arm means 7 automatically assumes an inclined position P2, as shown in Figure 2, causing the caster device 8 to move toward the outside of the workbench and bringing the leg seat 4 into contact with the floor surface G. As a result, the contact pressure and frictional force of the leg seat 4 prevent the workbench from moving (immobile state), keeping it stably placed on the floor surface G and ensuring safety when working at height.

In the illustrated embodiment, as an example, the arm means 7 is configured so that rotating from an upright position toward the outside of the workbench causes the caster device 8 to move toward the outside as well, but this is not limited to this. The mounting fixture 6 may be fixed to the fixed member 5 in the opposite direction, causing the arm means 7 and caster device 8 to move toward the inside of the workbench, or even in a direction that intersects the line connecting the outside and inside (i.e., the longitudinal direction of the beam member 3).

The caster device 8 is composed of a mounting bolt 9 extending vertically, a support member 11 with a fork that rotatably supports the wheel 10 via the axle 10a below the mounting bolt 9, and a connecting member 12 that swivels to connect the support member 11 to the mounting bolt 9. In the illustrated example, the connecting member 12 is composed of a retainer with a bearing built in. In this case, as shown in Figure 5(A), the axle 10a of the wheel 10 is positioned at a position offset laterally by a distance L1 from the axis V of the mounting bolt 9.

The fixing member 5 may be formed from a separate member from the beam member 3, but in the illustrated embodiment, it is formed from the beam member 3 and is formed with a substantially U-shaped cross section from a metal extrusion such as aluminum. The mounting fixture 6 is formed from a metal fitting with a substantially U-shaped cross section that covers the outer periphery of the fixing member 9, and includes a side plate portion 6a that is attached to the outer surface of the fixing member 9, and upper and lower plate portions 6b and 6c that are bent from the upper and lower edges of the side plate portion 6a and attached to the upper and lower surfaces of the fixing member 9. The upper and lower plate portions 6b and 6c are fixed by inserting bolts 13 facing the inner surface of the fixing member 9 through the bolts and tightening nuts 14, thereby clamping the upper and lower surfaces of the fixing member 9.

The arm means 7 comprises a plate-shaped pivot portion 7a that fits along the upper plate portion 6b of the mounting fixture 6, a plate-shaped arm portion 7b that is bent from the pivot portion 7a and extends downward along the side plate portion 6a of the mounting fixture 6, and a plate-shaped mounting portion 7c that is bent from the lower end of the arm portion 7b and protrudes toward the outside of the workbench, and is pivotally supported on the mounting fixture 6 via a substantially cylindrical shaft support portion 15 that is integrally formed along the edge of the pivot portion 7a.

An arm means 7 having such a pivot portion 7a, arm portion 7b, mounting portion 7c, and pivot support portion 15 integrally formed can be provided, for example, by cutting a metal extrusion such as aluminum.

The pivot support portion 15 of the arm means 7 is interposed between support pieces 16, 16 erected on both side edges of the upper plate portion 6a of the mounting fixture 6. A pivot shaft 17 made of a bolt is inserted through the pivot support portion 15, and a locking nut 18 is screwed in to the pivot support portion 15, allowing the arm means 7 to change position between an upright position P1 and an inclined position P2. The arm means 7 is fixed by inserting the mounting bolt 9 of the caster device 8 from bottom to top through the mounting portion 7c and tightening the mounting nut 19.

For this reason, as shown in Figure 5(B), the axis V of the mounting bolt 9 of the caster device 8 is positioned at a distance L2 offset from the center of rotation of the arm means 7, which is determined by the pivot shaft 17, toward the outside of the workbench. In this case, as shown in the figure, it is preferable that when the arm means 7 is in the upright position P1, the axis V of the arm portion 7b and the mounting bolt 9 is configured to be perpendicular to the floor surface.

In this configuration, a holding means 20 is provided to hold the arm means 7 in the upright position P1.

The holding means 20 is preferably configured with magnet means 21 that is magnetically attracted in contact when the arm means 7 is in the upright position P1 and separates when it is in the inclined position P2. In the embodiment shown in Figures 1 to 6, permanent magnets 21a and magnetic bodies 21b are provided on the inner surfaces of the opposing arm portions 7b and the side plate portions 6a of the mounting fixture 6.

In the illustrated example, the permanent magnet 21a attached to the inner surface of the arm portion 7b is secured with a flat head bolt (a bolt with a flat head), and the mounting fixture 6 is made of a magnetic material such as iron, so that the side plate portion 6a forms the magnetic body 21b. However, the magnetic body 21b may also be formed by securing a separate piece of iron plate or the like. Therefore, contrary to what is shown in the figure, the magnet means 21 may be constructed by securing the permanent magnet 21a to the side plate portion 6a of the mounting fixture 6 (or to the side surface of the fixing member 9 if the side surface is exposed), and securing the magnetic body 21b such as an iron piece to the inner surface of the arm portion 7b.

In this case, as shown in Figure 3, multiple mounting holes 23 may be provided in the arm portion 7b of the arm means 7, and the magnetic attraction force may be adjusted by selecting the mounting position and number of permanent magnets 21a.

(effect)
The operation is shown in Figures 5 and 6. As described above, when no worker is on the workbench and the workbench has a predetermined weight W1, as shown in Figure 5, the arm means 7 is held in an upright position P1 by the holding means 20 consisting of the magnet means 21, and the caster devices 8 have wheels 10 grounded in an attitude in which the axis V of the mounting bolt 9 is perpendicular to the floor surface G. Therefore, the leg base 4 of the workbench is raised to a position H above the floor surface G, and the workbench is movably supported by the caster devices 8 (movable state). Therefore, the caster devices 8 can freely run on the floor surface, and the wheels 10 can swivel freely at this time.

As shown in Figure 5 (B), the contact point between the pivot shaft 17 of the arm means 7 and the wheel 10 of the caster device 8 (axis V of the mounting bolt 9 in the illustrated case) is offset by a distance L2 in the direction of rotation of the arm means 7. As a result, when a predetermined weight W1 of the workbench acts on the pivot shaft 17, a moment indicated by arrow F1 is generated in the arm means 7; however, the magnetic force of the magnet means 21 is configured to overcome this moment, thereby maintaining the arm means 7 in an upright position P1.

When a worker steps onto the workbench, causing the workbench to increase in weight W2 from the predetermined weight W1, as shown in Figure 6, the moment generated in the arm means 7 increases, causing the magnet means 21 (holding means 20) to lose its magnetic attraction (holding) and automatically causing the arm means 7 to assume an inclined position P2. At this time, the caster device 8 moves toward the outside of the workbench, causing the leg seat 4 to contact the floor surface G. As a result, the ground contact pressure and frictional force of the leg seat 4 prevent the workbench from moving (immovable state).

As shown in Figure 5(B), even if the caster device 8 supported by the arm means 7 in the upright position P1 is in a position where the direction of travel of the wheels 10 intersects the direction of rotation of the arm means 7 before the worker boards the workbench, the wheels 10 can be swiveled and rolled in the direction of rotation of the arm means 7. That is, as shown in Figure 6(A), when the arm means 7 begins to change position from the upright position P1 to the tilted position P2, the mounting portion 7c of the arm portion 7b descends while tilting the axis V of the mounting bolt 9 of the caster device 8, and the wheels 10 are automatically rotated toward the outside of the workbench via the connecting member 12.

Figure 7 shows the holding force of the holding means required to hold the workbench in a movable state. Figure 7(A) shows the magnet means 106 that holds the caster device 101 in the prior art described above with reference to Figure 12, and Figure 7(B) shows the magnet means 21 (holding means 20) that holds the caster device 8 in the embodiment of the present invention described above.

In the case of conventional technology, as shown in Figure 7(A), the predetermined weight W1 of the workbench acts as a force that causes the vertically arranged socket 103 and sliding shaft 104 to slide up and down relative to each other. Therefore, in order to prevent sliding, the magnetic attraction force F1 of the magnet means 106 that magnetically attracts the upper end of the sliding shaft 104 and the upper end surface of the socket 103 must be W1≦F1.

In contrast, in an embodiment of the present invention, as shown in Figure 7(B), the predetermined weight W1 of the workbench acts on the arm means 7 as a moment M in the direction of rotation about the pivot shaft 17, so the magnetic force F2 of the magnet means 21 (holding means 20) required to prevent rotation is sufficient if W1 > F2.

Therefore, while the prior art requires a large magnet 106 with a strong magnetic force, the embodiment of the present invention only requires the use of a magnet means 21 with a relatively weak magnetic force, which contributes to cost reduction. Furthermore, there is flexibility in the design of the yield point of the magnetic force that separates when subjected to an increase in weight W2, making manufacturing easier; this difference is particularly noticeable when implemented on large workbenches, which are considered to be very heavy.

In a preferred embodiment, as shown in Figure 8, a stopper means 24 is provided between the upper plate portion 6b of the mounting fixture 6 and the pivot support portion 15 of the arm means 7 to prevent the arm means 7 from rotating further outward from the inclined position P2 when the arm means 7 is in the inclined position P2.

In the illustrated example, the stopper means 24 is formed by abutting the lower jaw piece 24a, which extends from the approximately cylindrical support portion 15 in the opposite direction to the pivot portion 7a, against the upper plate portion 6b. That is, as shown in Figure 8(A), when the arm means 7 is in the inclined position P2 (at which point the foot base 4 is in contact with the floor), the lower jaw piece 24a is close to but does not abut the upper plate portion 6b. Therefore, the lower jaw piece 24a is not subjected to load due to the increase in weight caused by the worker boarding the machine. However, if the column base 2 tilts due to the workbench swaying, etc., and the arm means 7 tilts further from the inclined position P2, the lower jaw piece 24a abuts against the upper plate portion 6b, as shown in Figure 8(B), thereby preventing the column base 2 from tilting.

In other words, when a worker mounts the platform to perform work at height, the base 4 touches the floor, and the caster device 8 is positioned outside the work platform by the arm means 7, which is in inclined position P2 with the wheels 10 in contact with the floor, and the stopper means 24 prevents the platform from moving further outward from inclined position P2, thereby functioning as an outrigger to prevent the work platform from tipping over. This outrigger function is more effective the higher the work platform, in other words, the longer the column base 2.

In this case, the outrigger effect can be further improved by using a caster device 8 equipped with a braking device (locking device) that prevents the wheels 10 from rotating.

In the illustrated embodiment, in which the holding means 20 is configured using the magnet means 21, when the worker finishes his work and steps down from the workbench, the arm means 7 does not automatically return from the inclined position P2 to its original upright position P1. However, if the worker lifts the workbench, the weight of the caster device 8 can automatically rotate the arm means 7 toward the upright position P1, and the upright position P1 is maintained by the magnet means 21.

As is clear from the above explanation, when the workbench is in a movable state (with the leg base 4 raised), the arm means 7 maintains an upright position P1 and the caster device 8 is positioned near the fixed member 5. In contrast, when the workbench is in an immovable state (with the leg base 4 on the ground), the arm means 7 assumes an inclined position P2, extends outward, and the caster device 8 is positioned outward from the fixed member 9. Therefore, just by looking from above, the worker can easily tell whether the workbench is in a movable or immovable state, so there is no risk of the worker mistaking the workbench for a movable state when it is actually immovable and dragging the leg base 4 on the floor.

(Another embodiment of the holding means)
9 shows another embodiment of the holding means 20. The holding means 20 is configured with a magnet means 21 consisting of a permanent magnet 21a and a magnetic body 21b. This is similar to the above-mentioned embodiment, but the permanent magnet 21a is fixed to the underside of the pivot part 7a of the arm means 7 with a flat head bolt 22, and the magnetic body 21b is formed by the upper plate part 6b of the mounting fixture 6 made of a magnetic material such as iron.

As shown in Figure 9(A), when the arm means 7 is in the upright position P1, the permanent magnet 21a and the magnetic body 21b are magnetically attracted to each other, maintaining the upright position P1. When the arm means 7 rotates from this state toward the inclined position P2, as shown in Figure 9(B), the permanent magnet 21a and the magnetic body 21b move away from each other, allowing the arm means 7 to rotate toward the inclined position P2. As mentioned above, the magnetic body 21b may be formed from a separately fixed piece of iron or the like. Furthermore, the relationship between the permanent magnet 21a and the magnetic body 21b may be reversed; that is, the permanent magnet 21a may be provided on the upper surface of the upper plate portion 6b, and the magnetic body 21b may be provided on the lower surface of the pivot portion 7a.

(Yet another embodiment of the holding means)
10 shows yet another embodiment of the holding means 20. The holding means 20 is configured by a spring 25 that elastically holds the arm means 7 in the upright position P1 and allows it to be deformed against the elastic force to assume the inclined position P2.

In the illustrated example, a double torsion spring made of bent spring wire is used, with a pair of coil portions 25b, 25b provided on both ends of a gate-shaped elastically biased portion 25a, and a support portion 25c extending from each coil portion 25b. The elastically biased portion 25a is in elastic contact with the upper surface of the pivot portion 7a of the arm means 7, and the coil portions 25b, 25b are located on both sides of the pivot support portion 15 and inserted onto the pivot shaft 17, and the support portion 25c is supported on the upper plate portion 6b of the mounting fixture 6, thereby elastically biasing the arm means 7 toward the upright position P1.

Therefore, the resilient force of the spring 25 normally keeps the arm means 7 in the upright position P1, allowing the arm means 7, together with the caster device 8, to support a predetermined weight of the workbench, keeping the leg base 4 above the floor and allowing the workbench to move.

When a worker steps onto the work platform, causing the weight to increase above the specified weight, the spring 25 elastically deforms, as shown by the dotted line in Figure 10 (A), allowing the arm means 7 to rotate toward the inclined position P2.

This embodiment has the advantage that when the worker finishes work and steps down from the workbench, the elastic force of the spring 25 automatically returns the arm means 7 to its original upright position P1.

(Another embodiment related to use examples)
11 shows another embodiment of the use of the arm means 7 equipped with the caster device 8. In this embodiment, the above-mentioned stopper means 24 (FIG. 8) is not provided, and the arm means 7 is configured to be able to rotate upward about the pivot shaft 17 from the standing posture P1.

For this reason, when the workbench is to be used continuously in an immobile state, or when it is to be stored without being used, the worker can lift the arm means 7 and place it in the inverted position as shown, thereby storing the caster device 8 together with the arm means 7 in a predetermined position on the workbench. In the illustrated example, the inverted position is maintained by supporting the pivot portion 7a of the arm means 7 against the upper plate portion 6b of the mounting fixture 6, but a separate locking means may also be provided to lock the arm means 7 in the inverted position in a detachable manner.

G Floor surface H Upper position P1 Upright position P2 Inclined position 1 Top plate 2 Column base 3 Beam member 4 Leg seat 5 Fixing member 6 Mounting fixture 6a Side plate portion 6b Upper plate portion 6c Lower plate portion 7 Arm means 7a Pivot portion 7b Arm portion 7c Mounting portion 8 Caster device 9 Mounting bolt V Axis of mounting bolt 10 Wheel 10a Axle 11 Support member 12 Connecting member 13 Bolt 14 Nut 15 Axle support portion 16 Support piece 16a Eaves piece 17 Pivot shaft 18 Nut 19 Mounting nut 20 Holding means 21 Magnet means 21a Permanent magnet 21b Magnetic body 22 Flat head bolt 23 Mounting hole 24 Stopper means 24a Lower jaw piece 25 Spring 25a Elastically biasing portion 25b Coil portion 25c Support portion

Claims (5)

A workbench of a predetermined weight on which a worker gets on and off is provided with a base (4) that is brought into contact with the floor surface when the weight of the workbench increases from the predetermined weight due to the worker getting on, and a caster device (8) that movably supports the base in a state where it is lifted off the floor surface when the worker is not getting on and the workbench is at the predetermined weight,
The caster device (8) is attached to a mounting fixture (6) fixed to a predetermined fixed member (5) of the workbench via an arm means (7),
The arm means (7) has an arm portion (7b) extending downward from a pivot portion (7a) pivotally supported on the mounting fixture around a horizontal axis, and the caster device (8) is attached to a portion of the arm portion near the lower end at a position offset from the horizontal axis in the direction of rotation. The arm means (7) is freely changeable between an upright position (P1) in which the arm portion is substantially perpendicular to the floor surface and an inclined position (P2) in which the arm portion is rotated sideways toward the outside of the workbench . When the arm means (7) is in the upright position (P1), the caster device (8) is positioned near the fixed member (5) to raise the leg seat (4) off the floor, while when the arm means (7) is in the inclined position (P2), the caster device (8) is moved sideways to bring the leg seat (4) into contact with the ground.
A holding means (20) is provided to hold the arm means (7) in an upright position (P1),
The holding means (20) is configured to hold the arm means in an upright position when the work platform is at a predetermined weight (W1), but allows the arm means to be in an inclined position when the work platform experiences a weight increase (W2);
A workbench characterized in that a stopper means (24) is provided between one of the fixing member (5) and the mounting fixture (6) and the arm means (7) to prevent the arm means (7) from further rotating from the inclined position (P2) toward the outside of the workbench . A workbench of a predetermined weight on which a worker gets on and off is provided with a base (4) that is brought into contact with the floor surface when the weight of the workbench increases from the predetermined weight due to the worker getting on, and a caster device (8) that movably supports the base in a state where it is lifted off the floor surface when the worker is not getting on and the workbench is at the predetermined weight,
The caster device (8) includes a mounting bolt (9) extending in the vertical direction, a support member (11) that supports a wheel (10) below the mounting bolt at a position offset laterally from the axis of the mounting bolt, and a connecting member (12) that rotatably connects the support member to the mounting bolt, and is attached via an arm means (7) to a mounting fixture (6) fixed to a predetermined fixed member (5) of the workbench.
The arm means (7) has an arm portion (7b) extending downward from a pivot portion (7a) pivotally supported on the mounting fixture around a horizontal axis, and the caster device (8) is attached to a portion of the arm portion near the lower end at a position offset from the horizontal axis in the direction of rotation. The arm means (7) is configured to be changeable between an upright position (P1) in which the arm portion is substantially perpendicular to the floor surface and an inclined position (P2) in which the arm portion is rotated sideways. When the arm means (7) is in the upright position (P1), the caster device (8) is positioned near the fixed member (5) to raise the leg seat (4) above the floor surface, while when the arm means (7) is in the inclined position (P2), the caster device (8) is moved sideways to bring the leg seat (4) into contact with the ground.
A holding means (20) is provided to hold the arm means (7) in an upright position (P1),
The holding means (20) is configured to hold the arm means in an upright position when the work platform is at a predetermined weight (W1), but allows the arm means to be in an inclined position when the work platform experiences a weight increase (W2);
This workbench is characterized in that when the arm means (7) changes its position from an upright position to an inclined position, the mounting bolts (9) of the caster device are tilted, causing the wheels (10) to rotate in the direction of rotation of the arm section . A workbench of a predetermined weight on which a worker gets on and off is provided with a base (4) that is brought into contact with the floor surface when the weight of the workbench increases from the predetermined weight due to the worker getting on, and a caster device (8) that movably supports the base in a state where it is lifted off the floor surface when the worker is not getting on and the workbench is at the predetermined weight,
The caster device (8) includes a mounting bolt (9) extending in the vertical direction, a support member (11) that supports a wheel (10) below the mounting bolt at a position offset laterally from the axis of the mounting bolt, and a connecting member (12) that rotatably connects the support member to the mounting bolt, and is attached via an arm means (7) to a mounting fixture (6) fixed to a predetermined fixed member (5) of the workbench.
The arm means (7) comprises a pivot portion (7a) pivotally supported on the mounting fixture around a horizontal axis, an arm portion (7b) extending downward from the pivot portion, and a mounting portion (7c) extending from a lower end of the arm portion at a position offset from the horizontal axis in the direction of rotation, and a mounting bolt (9) of the caster device is fixed to the mounting portion.
The arm means (7) is configured to be freely changeable between an upright position (P1) in which the arm portion is substantially perpendicular to the floor surface and an inclined position (P2) in which the arm portion is rotated in the extending direction of the mounting portion (7c), and when in the upright position (P1), the caster device (8) is positioned near the fixed member (5) to raise the leg seat (4) off the floor surface, while when in the inclined position (P2), the caster device (8) is moved in the extending direction of the mounting portion (7c) to bring the leg seat (4) into contact with the ground.
A holding means (20) is provided to hold the arm means (7) in an upright position (P1),
The holding means (20) has a holding force for holding the arm means in an upright position, and the holding force is greater than the moment generated in the arm means (7) when the workbench is at a predetermined weight (W1), but is configured to allow the arm means to assume an inclined position (P2) by being defeated by the moment generated in the arm means (7) when the workbench is increased in weight (W2);
A workbench characterized in that, when the arm means changes its position from an upright position to an inclined position, the mounting portion (7c) of the arm portion tilts the mounting bolt (9) of the caster device, thereby rotating the wheels (10) in the rotation direction of the arm portion. A workbench as described in claim 1, 2, or 3, characterized in that the holding means (20) is composed of magnet means (21) that are magnetically attracted in abutting contact when the arm means (7) is in the upright position (P1) and are separated when the arm means (7) is in the inclined position (P2). A workbench as described in claim 1, 2, or 3, characterized in that the holding means (20) is composed of a spring (25) that elastically holds the arm means (7) in an upright position (P1) and allows the arm means to be placed in an inclined position (P2) by deforming against the elasticity.