Workbench

Abstract

To provide a work table which grounds a leg seat when worker's boarding causes a weight increase from a prescribed weight and is provided with a caster device which supports the leg seat movable in a floating state from the floor surface when the work table has the prescribed weight when the worker gets off.SOLUTION: A caster device (8) is attached to a lower end vicinity part of an arm part (7b) extending downward from a pivot part (7a) of arm means (7) which can freely change its posture between an upright posture and an inclined posture, and is configured to make a leg seat (4) float from a floor surface during the upright posture (P1) and ground the leg seat (4) by moving the caster device outward during the inclined posture (P2). The caster device is provided with holding means (20) for allowing the arm means to take the inclined posture when a weight increase (W2) is generated at the work table even though the arm means takes the upright posture when the work table has a prescribed weight (W1).SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a workbench, and more particularly to a workbench equipped with a base that is brought into contact with 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. [Background technology]

[0002] There are various types of work platforms available for workers to use when working at heights, and one known type is one that can be moved on the floor using casters when no worker is on it, but can be placed in a stable state by being placed on the floor when a worker is on it to work (Patent Document 1).Incidentally, it should be understood that in this specification, the term "work platform" does not limit to specific work platforms such as step ladders, stools, and portable work platforms, but broadly includes any device that provides a foothold for workers to work at a position higher than the floor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6630954 Summary of the Invention [Problem to be solved by the invention]

[0004] As shown in Figure 12, for example, a 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 portion 104 inserted slidably into the socket 103 and a swivelable wheel 105 attached to the lower end thereof, and magnet means 106 consisting of an abutment body and a receiving body that are magnetically attracted to each other between the upper end of the sliding shaft portion 104 inserted from the socket 103 and the upper end surface of the socket 103, and when the workbench is lifted, the sliding shaft portion 104 descends, causing the abutment body to be placed in abutment against the receiving body and to be magnetically attracted by the magnet means 106.

[0005] According to Patent Document 1, the magnet means 106 supports the weight of the workbench in a state where the contact body is placed on the receiving body and magnetically attracted 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 foot seat 108 provided at the lower end of the column base 107 raised above the floor surface G. Therefore, the workbench is in a "movable state" where it can be moved by running on the floor.

[0006] 12(B), when a worker steps on the workbench, the increased weight is received by the socket 103, which releases the magnetically attached state, causing the workbench to descend together with the socket 103, and the leg seat 108 to come 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 an "immovable state" where it is stably installed so as not to move on the floor.

[0007] At this time, when the worker descends from the workbench and lifts the workbench to raise the socket 103, the leg seat 108 moves away from the floor surface and the sliding shaft portion 104 descends, causing the contact body to be placed on the receiving body, and the magnet means 106 becomes magnetically attracted, returning the socket to its original "movable state."

[0008] 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 may cause wear and other damage.

[0009] 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 vertical sliding of the caster's socket and the sliding shaft relative to each other, but the sliding stroke is short, approximately 10 mm. Therefore, simply visually inspecting from above, it is not always easy for a worker to determine whether the base is in contact with the floor or whether the contact and receiving bodies of the caster are in contact or separate states. Therefore, a worker may mistakenly believe that the base is in an "immovable state" and drag the base across the floor. This not only damages the base, but also, if the direction of rotation of the caster's wheels crosses the dragging direction, it may damage the wheel's support parts (axles and forks).

[0010] Generally, a workbench is provided with a total of four pedestals 107 at least at the four corners of the rectangular top plate, and therefore, the caster devices 101 are also attached near each pedestal 107. In other words, a total of four caster devices 101 are arranged at least near the four corners.

[0011] Therefore, when a worker steps onto the workbench, if the worker's weight evenly distributes the load across the entire top surface of the workbench, the sockets 103 and sliding shafts 104 slide vertically relative to each other between the four caster devices 101 at almost the same time, allowing the base seats 108 of the four column bases 107 to touch the ground.

[0012] However, if a worker stands near the edge of the tabletop, the tabletop will be subjected to an unbalanced load, which may cause the workbench to tilt. That is, the caster devices 101 located close to the worker's position will perform relative sliding between the sockets 103 and the sliding shafts 104 quickly, but the caster devices 101 located further away will perform relative sliding between the sockets 103 and the sliding shafts 104 with a delay, which will cause the workbench to tilt.

[0013] 12(C), when the workbench tilts, the axis V of the socket 103 and sliding shaft 104 of the caster device 101 deviates from the vertical direction and tilts, which may cause distortion of the sliding surfaces of the socket 103 and sliding shaft 104 due to the vertical load W, resulting in damage. Moreover, in a caster device 101 where distortion has occurred, the relative sliding of the socket 103 and sliding shaft 104 is prevented, so that the base seat 108 of the column base 107 located nearby does not contact the ground, and the "immobility state" is not complete, which may result in a danger to work.

[0014] Furthermore, since the "movable state" is achieved by preventing the socket 103 and the sliding shaft portion 104 from sliding up and down by the magnet means 106, there is a problem that when applied to a large workbench, for example, a large magnet means 106 with strong magnetic force is required to withstand the large weight.

[0015] An object of the present invention is to provide a workbench that solves the above problems. [Means for solving the problem]

[0016] Therefore, the present invention provides a first means for providing a workbench of a predetermined weight on which a worker gets on and off, the workbench having a leg 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 leg base in a state where it is lifted off the floor when the worker is not getting on and the workbench is at the predetermined weight, the caster device being attached to a fixture fixed to a predetermined fixed member of the workbench via an arm means, the arm means having an arm portion that extends downward from a pivot portion that is pivotally supported on the fixture around a horizontal axis, and the caster device being 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 position of the arm unit can be freely changed between an upright position in which the arm unit is nearly perpendicular to the floor surface and an inclined position in which the arm unit is rotated sideways. When in the upright position, the caster device is positioned near a fixed member to raise the foot seat off the floor surface, while when in the inclined position, the caster device is moved sideways to bring the foot seat into contact with the ground. A holding means is provided to hold the arm means in the upright position, and the holding means is configured to hold the arm means in the upright position when the workbench is at a predetermined weight, but to allow the arm means to be in the inclined position when the weight of the workbench increases.

[0017] The second means of the present invention is a workbench of a predetermined weight on which a worker gets on and off, the workbench having 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 supports the base so that it can be moved while being lifted off the floor when the worker is not getting on and the workbench is at the predetermined weight, the caster device comprising a mounting bolt extending in the vertical direction, and a support member that supports a wheel at a position below the mounting bolt and 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 position can be freely changed between an upright position, which 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 to raise the leg seat off the floor, while when in the inclined position, the caster device is moved in the extension direction of the mounting portion to bring the leg seat into contact with the floor. A holding means is provided to hold the arm means in the upright position, and the holding means has a holding force to hold the arm means in the upright position. This holding force is greater than the moment generated in the arm means when the workbench is at a predetermined weight, but is greater than the moment generated in the arm means when the workbench is heavier, allowing the arm means to be in an inclined position. When the arm means changes position from the upright position to the inclined position, the mounting portion of the arm portion tilts the mounting bolt of the caster device, causing the wheel to swivel in the rotation direction of the arm portion.

[0018] 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, a stopper means is provided between one of the fixing member and the mounting fixture and the arm means to prevent the arm means from rotating further from the inclined position toward the outside of the workbench when the arm means is in an inclined position.

[0019] In a preferred embodiment, the holding means is constituted by magnet means which is magnetically attracted in contact with the arm means when the arm means is in an upright position and which is separated from the arm means when the arm means is in an inclined position.

[0020] In another embodiment, the holding means comprises a spring that elastically holds the arm means in an upright position and allows the arm means to be in an inclined position by deforming against the elasticity. [Effects of the Invention]

[0021] According to the present invention, when a worker steps onto a work platform that has been set to the "movable state," even if the work platform is subjected to an unbalanced load, all of the caster devices 8 can be moved sideways appropriately to allow all of the leg seats 4 to touch the ground almost simultaneously, thereby ensuring work safety. Moreover, the mechanism for moving the caster devices 8 sideways is made up 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 or the like. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a perspective view showing a movable state of a workbench according to one embodiment of the present invention, with the base seat raised above the floor surface and the wheels of the caster device in contact with the floor surface so as to be able to roll freely. FIG. [Figure 2] 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. [Figure 3] FIG. 1 is an exploded perspective view showing members and components constituting one embodiment of the present invention. [Figure 4] FIG. 10 is a cross-sectional view showing a state in which the arm means is in an upright position. [Figure 5] 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. [Figure 6] 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 posture change from the upright posture to the tilted posture has started, and (B) is a cross section showing the state when the tilted posture has been achieved. [Figure 7] Regarding the differences between the prior art and one embodiment of the present invention, (A) is a cross-sectional view showing the prior art, and (B) is a cross-sectional view showing one embodiment of the present invention. [Figure 8] 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. [Figure 9] 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. [Figure 10] 10A and 10B show a spring constituting another embodiment of 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 when the arm means has rotated toward a tilted position against the holding force. [Figure 11] 10A and 10B are cross-sectional views illustrating another embodiment for use. [Figure 12] 1A and 1B show a cross-sectional view of 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. DETAILED DESCRIPTION OF THE INVENTION

[0023] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0024] 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, with adjacent column bases 2 connected near their lower ends by beam members 3, and a foot seat 4 attached to the lower end of each column base 2.

[0025] Although not shown in the figure, for example, 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.

[0026] The work platform itself has a predetermined weight, and when a worker sits on it, the weight increases from the predetermined weight.

[0027] Therefore, 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 of the workbench is set to a predetermined value, the caster devices 8 movably support the workbench with the leg base 4 suspended at a position H above the floor G by a predetermined distance by setting the arm means 7 in an upright position P1 as shown in FIG. 1 (movable state). This allows the worker to move the workbench to a desired location by running the caster devices 8 on the floor.

[0028] On the other hand, when the weight of the workbench increases from a predetermined weight due to a worker getting on it, the arm means 7 is automatically tilted to a tilted 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 ground contact pressure and frictional force of the leg seat 4 prevent the workbench from moving (immovable state), and the workbench is stably placed on the floor surface G, ensuring safety when working at height.

[0029] In the illustrated embodiment, as an example, the arm means 7 is configured to rotate from an upright position toward the outside of the workbench, thereby moving the caster device 8 toward the outside as well, but this is not limited to this. The arm means 7 and caster device 8 may be configured to move toward the inside of the workbench by fixing the mounting fixture 6 in the opposite direction to the fixed member 5, and further, they may be configured to move in a direction intersecting the line connecting the outside and the inside (i.e., the longitudinal direction of the beam member 3).

[0030] The caster device 8 is composed of a mounting bolt 9 extending in the vertical direction, a support member 11 with a fork portion that rotatably supports the wheel 10 via an axle 10a below the mounting bolt 9, and a connecting member 12 that rotatably connects the support member 11 to the mounting bolt 9. In the illustrated example, the connecting member 12 is composed of a retainer with a built-in bearing. In this case, as shown in Figure 5(A), the axle 10a of the wheel 10 is positioned at a position offset by a distance L1 to the side with respect to the axis V of the mounting bolt 9.

[0031] The fixing member 5 may be formed of a separate member from the beam member 3, but in the illustrated embodiment, it is formed of the beam member 3 and is formed of a metal extrusion such as aluminum so as to have a substantially U-shaped cross section. The mounting fixture 6 is formed of 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 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 6a and attached to the upper and lower surfaces of the fixing member 9. The upper and lower plate portions 6b, 6c are fixed by inserting bolts 13 facing the inner surface of the fixing member 9 through the bolts and fastening nuts 14, thereby clamping the upper and lower surfaces of the fixing member 9.

[0032] The arm means 7 comprises a plate-shaped pivot portion 7a that runs 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 an approximately cylindrical shaft support portion 15 that is integrally formed along the edge of the pivot portion 7a.

[0033] The arm means 7 having the pivot portion 7a, arm portion 7b, mounting portion 7c and axial support portion 15 integrally formed can be provided by cutting an extruded metal material such as aluminum.

[0034] The support portion 15 of the arm means 7 is interposed between support pieces 16, 16 erected from both side edges of the upper plate portion 6a of the mounting fixture 6, and a pivot shaft 17 made of a bolt is inserted through it, and a nut 18 to prevent it from coming off is screwed onto it, so that the arm means 7 is pivotally supported around the axis of the pivot shaft 17, thereby making it possible to change its position between an upright position P1 and an inclined position P2.The mounting portion 7c is fixed by inserting a mounting bolt 9 of the caster device 8 from bottom to top and tightening a mounting nut 19.

[0035] 5(B), the axis V of the mounting bolt 9 of the caster device 8 is positioned at a position offset by a distance L2 toward the outside of the workbench from the center of rotation of the arm means 7 defined by the pivot shaft 17. In this case, as shown in the figure, it is preferable that when the arm means 7 is in an 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.

[0036] In this configuration, a holding means 20 is provided for holding the arm means 7 in the standing position P1.

[0037] The holding means 20 is preferably configured by magnet means 21 that is magnetically attracted in a contacting state when the arm means 7 is in the upright posture P1 and that separates when the arm means 7 is in the inclined posture 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 arm portions 7b and the side plate portions 6a of the mounting fixture 6, which face each other.

[0038] In the illustrated example, the permanent magnet 21a attached to the inner surface of the arm portion 7b is fixed 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, but the magnetic body 21b may also be formed by separately fixing a piece of iron plate or the like. Therefore, contrary to what is shown in the figure, the magnet means 21 may be formed by fixing 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 fixing the magnetic body 21b such as an iron piece to the inner surface of the arm portion 7b.

[0039] In this case, as shown in FIG. 3, a plurality of 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 of the permanent magnets 21a and the number of magnets to be mounted.

[0040] (action) The operation is shown in Figures 5 and 6. As described above, when no worker is standing on the workbench and the workbench is at 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 their 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 suspended at 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 are free to run on the floor surface, and at this time, the wheels 10 are free to swivel.

[0041] 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 rotation direction of the arm means 7. Therefore, 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, but 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.

[0042] Therefore, when a worker steps onto the workbench and the weight of the workbench increases from a predetermined weight W1 to W2, as shown in Fig. 6, the moment generated in the arm means 7 increases, which causes the magnetic attraction (holding) of the magnet means 21 (holding means 20) to be released, and the arm means 7 automatically assumes an inclined posture P2. At this time, the caster devices 8 are moved toward the outside of the workbench, causing the leg seats 4 to contact the floor surface G. Therefore, the ground contact pressure and frictional force of the leg seats 4 prevent the workbench from moving (immovable state).

[0043] As shown in Fig. 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 traveling direction of the wheels 10 intersects with the rotation direction of the arm means 7 before the worker gets on, the wheels 10 can be rotated and rolled in the rotation direction of the arm means 7. That is, as shown in Fig. 6(A), when the arm means 7 starts to change its 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, so that the wheels 10 are automatically rotated toward the outside of the workbench via the connecting member 12.

[0044] The holding force of the holding means required to hold the workbench in a movable state is shown in Figure 7. 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.

[0045] In the case of the prior art, as shown in Figure 7(A), the predetermined weight W1 of the workbench acts as a force that causes the socket 103 and sliding shaft 104, which are arranged vertically, to slide up and down relative to each other, so in order to prevent sliding, the magnetic 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.

[0046] In contrast, in the case of 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 rotation direction around the pivot axis 17, so the magnetic force F2 of the magnet means 21 (holding means 20) required to prevent rotation is sufficient if W1 > F2.

[0047] 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 magnet means 21 with a relatively small magnetic force, which contributes to cost reduction. Moreover, there is flexibility in designing 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 applied to a large workbench that is considered to be heavy.

[0048] 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 portion 15 of the arm means 7 to prevent the arm means 7 from rotating further from the inclined position P2 toward the outside of the workbench.

[0049] In the illustrated example, the stopper means 24 is formed by abutting the upper plate 6b with the lower jaw 24a, which extends from the substantially cylindrical support 15 in the opposite direction to the pivot 7a. That is, as shown in FIG. 8(A), when the arm means 7 is in the tilted position P2 (when the foot base 4 is in contact with the floor), the lower jaw 24a is close to but not in contact with the upper plate 6b. Therefore, the lower jaw 24a is not subjected to a load due to the weight increase caused by the worker getting on the platform. However, if the base 2 tilts due to the workbench swaying, etc., and the arm means 7 further tilts from the tilted position P2, the lower jaw 24a will abut the upper plate 6b as shown in FIG. 8(B), thereby preventing the base 2 from tilting.

[0050] In other words, when a worker mounts the work 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 the inclined position P2 with the wheels 10 in the ground, and is prevented from moving further outward from the inclined position P2 by the stopper means 24, so that the outrigger function functions to prevent the work platform from tipping over. Such an outrigger function becomes more effective the higher the work platform, in other words, the longer the column base 2.

[0051] In this case, if a caster device 8 equipped with a braking device (locking device) that prevents the wheels 10 from rotating is used, the outrigger effect can be further improved.

[0052] In the illustrated embodiment in which the holding means 20 is constituted by the magnet means 21, when the worker finishes his work and descends from the workbench, the arm means 7 does not automatically return from the inclined position P2 to the original standing position P1, but if the worker lifts the workbench, the weight of the caster device 8 can automatically rotate the arm means 7 toward the standing position P1, and the standing position P1 is maintained by the magnet means 21.

[0053] As is clear from the above explanation, when the workbench is in a movable state (a state in which the leg base 4 is raised), the arm means 7 is maintained in 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 (a state in which the leg base 4 is on the ground), the arm means 7 is in an inclined position P2 and projects outward, and the caster device 8 is positioned outward from the fixed member 9. Therefore, a worker can easily recognize whether the workbench is in a movable state or an immovable state simply by looking from above, and 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.

[0054] (Another embodiment of the holding means) 9 shows another embodiment of the holding means 20. The holding means 20 is configured with 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.

[0055] As shown in FIG. 9(A), when the arm means 7 is in an 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 an inclined position P2, the permanent magnet 21a and the magnetic body 21b move away from each other, as shown in FIG. 9(B), allowing the arm means 7 to rotate toward the inclined position P2. As mentioned above, the magnetic body 21b may be formed of a separately fixed iron piece 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.

[0056] (Yet another embodiment of the holding means) 10 shows yet another embodiment of the holding means 20. The holding means 20 is configured with 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.

[0057] In the illustrated example, a double torsion spring formed by bending a spring wire is used, and a pair of coil portions 25b, 25b are provided on both ends of a gate-shaped elastically biasing portion 25a, and a support portion 25c extends from each coil portion 25b. The elastically biasing 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 around the pivot shaft 17, and the support portion 25c is supported by the upper plate portion 6b of the mounting fixture 6, thereby elastically biasing the arm means 7 toward the standing posture P1.

[0058] Therefore, the resilient force of the spring 25 normally keeps the arm means 7 in an upright position P1, so that the arm means 7 together with the caster device 8 supports a predetermined weight of the workbench, and the workbench is in a movable state with the leg base 4 lifted off the floor surface.

[0059] When a worker steps onto the work platform, causing the weight to increase from a predetermined weight, the spring 25 is elastically deformed, as shown by the chain line in Figure 10(A), allowing the arm means 7 to rotate toward the inclined position P2.

[0060] According to this embodiment, when the worker finishes work and steps down from the workbench, the elastic force of the spring 25 can automatically return the arm means 7 to the original standing position P1, which is an advantage.

[0061] (Another embodiment of the use example) 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.

[0062] Therefore, when the workbench is to be used continuously in an immovable state, or when the workbench 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 example shown, the inverted position is maintained by having the pivot part 7a of the arm means 7 abut against the upper plate part 6b of the mounting fixture 6, but a separate locking means may be provided to lock the arm means 7 in the inverted position in a detachable manner. [Explanation of symbols]

[0063] G Floor surface H Upper position P1 Standing posture P2 Inclined posture 1 baking sheet 2 pillar base 3 Beam members 4 Leg base 5 Fixing member 6 Mounting fixture 6a Side plate part 6b Upper plate 6c Lower plate part 7 Arm means 7a Cardinal branch 7b Arm section 7c Mounting part 8 Caster device 9 Mounting bolts V Axis of mounting bolt 10 wheels 10a axle 11 Support member 12 Connecting member 13 volts 14 Nut 15 axis branches 16 Support piece 16a Eave piece 17 Pivot 18 Nut 19 Mounting nut 20 Retention means 21 Magnet means 21a Permanent magnet 21b Magnetic material 22 Flat head bolt 23 Mounting hole 24 Stopper means 24a Mandibular piece 25 Spring 25a Elastic biasing portion 25b Coil section 25c connection branch

Claims

1. 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.

2. 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.

3. 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.

4. 4. A workbench according to claim 1, 2 or 3, characterized in that the holding means (20) is composed of magnet means (21) that is magnetically attracted in abutting contact when the arm means (7) is in an upright position (P1) and that separates when the arm means (7) is in an inclined position (P2).

5. 4. A workbench as claimed in claim 1, 2 or 3, characterized in that the holding means (20) is constituted by a spring (25) that elastically holds the arm means (7) in an upright position (P1) and allows the arm means (7) to be placed in an inclined position (P2) by deforming against the elasticity.

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