Workbench

Abstract

To provide a work table provided with leg bodies that can elevate a top plate freely.SOLUTION: In a work table, a pair of front and rear pedestals (14) constituting a foldable first leg body (12L) and second leg body (12R) provided at a lower side of a top plate are constituted by expansion pipes fitted with upper side outer pipes (14a) and lower side inner pipes (14b), and lower end vicinity portions of the outer pipes (14a) in a longer direction are connected with a first horizontal bar (16) and lower end vicinity portions of the inner pipes (14b) are connected by a second horizontal bar (17) between the pair of front and rear pedestals. Bridging a pair of expansion braces (20,20) formed with the expansion pipe between the first leg body and the second leg body, both end parts of expansion braces (20) are connected in an interposed state by being pivotally connected to the first horizontal bar (16) of one leg body and the second horizontal bar (17) of the other leg body between both leg bodies, and expansion braces are configured to be protrusively supported between the first horizontal bar and the second horizontal bar against external forces acting toward inner sides of both leg bodies.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a workbench, and particularly to a workbench with a top plate that can be raised and lowered freely.

Background Art

[0002] A workbench with a freely rising and falling function is known as proposed by the applicant (Patent Document 1).

[0003] The basic configuration of a known workbench (hereinafter referred to as "the prior art") is as shown in FIG. 1. Below a rectangular top plate 1 that forms a work floor, a first leg 2L and a second leg 2R are arranged at intervals in the left-right direction (the beam direction of the top plate). Each is pivotally connected via a pivot joint 3 so that it can be freely changed in posture between a closed-leg posture along the lower surface of the top plate 1 and an open-leg posture vertically suspended from the top plate 1.

[0004] Although not shown in the figure, the first leg 2L and the second leg 2R each constitute a frame body by connecting a pair of column legs 4 arranged at intervals in the front-rear direction (the width direction of the top plate) with a cross bar. Each column leg 4 is formed by a telescopic leg that telescopically fits an upper outer tube 4a and a lower inner tube 4b pivotally connected to the pivot joint 3 and can be fixed in a state of a predetermined telescopic length. A caster 5 is provided at the lower end of the inner tube 4b.

[0005] Between the pair of front and rear column legs, the lower end portion of the outer tube 4a is connected by a first cross bar 6, and a foldable folding brace 7 is provided. Both ends of the folding brace 7 are pivotally connected to the first cross bar 6 and substantially the central portion of the lower surface of the top plate 1. Therefore, the folding brace 7 can be rotated toward the closed-leg posture of the legs 2L and 2R by being valley-folded upward as shown by the chain line, and can be rotated toward the open-leg posture of the legs 2L and 2R by being unfolded linearly as shown by the solid line.

[0006] ] With the first leg 2L and the second leg 2R in the open-leg position, Figure 1(A) shows the column base 4, which is made of telescopic tubes, contracted to its shortest length, and therefore the top plate 1 is in the lowest position P1. Figure 1(B) shows the column base 4 extended to its longest length, and therefore the top plate 1 is in the highest position P2. Of course, in order to allow heights between both positions P1 and P2, the length of the column base 4 is configured to be selectable in stages, and although not shown in the figure, a locking mechanism is provided to fix the outer tube 4a and inner tube 4b in a non-extendable position when they are set to a predetermined length.

[0007] Incidentally, between the front and rear pair of column bases, the lower end of the inner tube 4b of the column base 4 is connected by a second crossbar 8. Therefore, between the first leg body 2L and the second leg body 2R, an extendable brace 9 is stretched between the second crossbar 8 of one leg body and the pivot point 3 of the other leg body.

[0008] The expandable brace 9 is formed by an expandable tube in which an upper inner tube 9b and a lower outer tube 9a are fitted together in an expandable and contractible manner and can be fixed in a predetermined expanded and contracted length. The upper end of the inner tube 9b is pivotally connected to a support member 3a that pivots the pivot of the pivot part 3, and the lower end of the outer tube 9a is pivotally connected to the second crossbar 8.

[0009] Therefore, when the column base 4 is extended to raise the tabletop 1 from its lowest position P1 to its highest position P2, the telescopic brace 9 also extends accordingly. Conversely, when the column base 4 is retracted to lower the tabletop 1, the telescopic brace 9 also retracts accordingly. Although not shown in the diagram, when the workbench is folded by positioning the legs 2L and 2R in a closed position along the underside of the tabletop 1, the telescopic brace 9 can be stored along the underside of the tabletop 1 in a retracted state by detaching the lower end of the outer tube 9a from the second crossbar 8. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] Japanese Patent Publication No. 2008-50824 [Overview of the project] [Problems that the invention aims to solve]

[0011] Incidentally, in a workbench where the column base 4 is constructed with telescopic legs that allow the top plate 1 to be raised and lowered, as in conventional technology, it is desirable to additionally configure reinforcing support structures on the leg bodies 2L and 2R so that the top plate 1 can be stably supported. In particular, when the column base 4 is extended, the overlapping portion of the outer tube 4a and the inner tube 4b (the portion indicated by the symbol 4x in Figure 1(B)) becomes shorter, reducing its strength, so a means of reinforcing it is necessary.

[0012] In this regard, the conventional technology is configured to supplement the strength of the column base 4 by spanning telescopic braces 9, 9 in an X-shape between the upper end of one leg (the support member 3a to which the upper end of the outer tube 4a is pivotally connected) and the lower end of the other leg (the second crossbar 8 at the lower end of the inner tube 4b) between the first leg 2L and the second leg 2R.

[0013] However, as shown in Figure 1(B), when a lateral external force F acts toward the inside of the first leg 2L or the second leg 2R, the strength of the column base 4 is not necessarily sufficient with the telescopic brace 9 configured as described above. Such an external force F can occur frequently, for example, when moving the workbench on the floor via the casters 5 to the work site, as the worker grips and pushes the column base 4.

[0014] When subjected to such an external force F, the outer tube 4a of the telescopic leg constituting the column base 4 appears to be supported by the bending brace 7. However, since the bending brace 7 is configured to bend in a valley shape as shown by the dashed line in the figure, it does not possess sufficient reinforcing support to withstand the powerful external force F.

[0015] On the other hand, the inner tube 4b of the telescopic leg constituting the column base 4 is supported by a telescopic brace 9. However, since the upper end of the telescopic brace 9 is pivotally connected to the support member 3a on the lower surface of the top plate 1, for example, in the highest position P2 shown in Figure 1(B), it is tilted significantly upward as shown by the angle θ, making it difficult to effectively resist the horizontal external force F.

[0016] Therefore, the column base 4 may be deformed in the bending direction by the external force F, and if it is deformed, the outer tube 4a and inner tube 4b will no longer be able to expand or contract.

[0017] Furthermore, even if the expansion brace 9 is modified to reinforce the lower end of the inner tube 4b so that it can withstand the external force F, as mentioned above, the outer tube 4a is not sufficiently supported by the bending brace 7 and is therefore prone to movement. As a result, the weak part 4x may deform.

[0018] Furthermore, in the case of conventional technology, when folding the leg body 2 into the closed position and folding it under the tabletop 1, it is necessary to store the telescopic brace 9 along the underside of the tabletop 1 in addition to the work of closing the leg body 2, which is cumbersome.

[0019] The present invention aims to provide a height-adjustable workbench that solves the above-mentioned problems. [Means for solving the problem]

[0020] Therefore, the means configured in the present invention are The work platform is configured such that a first leg and a second leg are positioned spaced apart to the left and right beneath the top plate forming the work surface, and the first and second leg are each constructed by connecting a pair of front and rear column legs with a crossbar, and each column leg is formed by an extendable leg in which the upper outer tube and lower inner tube are fitted together in an extendable and retractable manner and can be fixed in a predetermined extended and retracted length, and a pair of extendable braces are stretched between the first and second leg legs, and the crossbar connects the vicinity of the lower ends in the longitudinal direction of the outer tubes between the pair of front and rear column legs. The structure consists of a first crossbar and a second crossbar that connects the lower end of the inner tube to each other. Each of the pair of telescopic braces is formed by a telescopic tube that allows the outer tube and inner tube to be fitted together in an expandable and contractible manner and can be fixed in a predetermined expanded and contracted length. The ends of the telescopic tubes are connected in an interposed manner between the first and second leg bodies by pivoting the first crossbar of one leg body to the second crossbar of the other leg body, and are configured to provide bracing support between the first and second crossbars against external forces acting inward on both leg bodies.

[0021] Preferably, the telescopic brace, which is constructed using the aforementioned telescopic tube, has its tail end pivotally connected to the first crossbar so as to be rotatable in the vertical direction, and is provided with a hook means at its tip for rotatably gripping the second crossbar.

[0022] In this case, it is preferable that the first and second leg bodies are provided with holding means that, when their respective telescopic braces are set to a predetermined contracted length and rotated upright from the first crossbar, they are held in a position substantially parallel to the column base.

[0023] Preferably, the telescopic brace, composed of the telescopic tubes, is configured such that, with respect to the opposing directions of the outer tube and inner tube which are fitted together, a locking member that can be screwed into the tube is provided at the end of the outer tube in the opposing direction, and a plurality of locking holes arranged in a row in the direction of expansion and contraction are provided near the end of the inner tube in the opposing direction. The outer tube and inner tube are fixed together by screwing the locking member into the locking holes when the outer tube and inner tube are extended to a predetermined length.

[0024] More preferably, the telescopic brace constituted by the telescopic tube is provided with a locking pin elastically biased inwardly at the tip of the outer tube in the facing direction of the outer tube and the inner tube that are inserted into each other, and a locking portion for locking the locking pin and a tapered surface adjacent to the locking portion are provided in the vicinity of the tail end in the facing direction of the inner tube. When the outer tube and the inner tube are moved in the contraction direction relative to each other so that the telescopic tube has the shortest contraction length, after the tapered surface pushes up the locking pin against the elastic biasing force, in a state where the locking portion faces the locking pin, the locking pin is configured to be locked to the locking portion by the elastic biasing force.

Effect of the Invention

[0025] According to the present invention, between the first cross bar 16 on the column leg 14 of one leg and the second cross bar 17 on the column leg 14 of the other leg among the first leg body 12L and the second leg body 12R, the telescopic braces 20, 20 are spanned and pivotally connected to be connected in an interposed state, and are configured to tension and support between the lower end portion of the outer tube 14a (that is, the first cross bar 16) on the column leg 14 of one leg and the lower end portion of the inner tube 14b (that is, the second cross bar 17) on the column leg 14 of the other leg. Therefore, it is possible to suitably resist the lateral external force F acting toward the inside of the column leg 14, and there is an effect that the column leg 14 does not undergo distortion deformation.

Brief Description of the Drawings

[0026] [Figure 1] Shows a workbench according to the prior art, (A) is a front view showing the state where the top plate is in the lowest position, and (B) is a front view showing the state where the top plate is in the highest position. [Figure 2] Shows a workbench according to an embodiment of the present invention, (A) is a front view showing the state where the top plate is in the lowest position, and (B) is a front view showing the state where the top plate is in the highest position. [Figure 3] Regarding one embodiment, it is a perspective view showing the state where the legs are in the open-leg position and the telescopic brace is in the stored position, and the top plate is in the lowest position. [Figure 4]This is a perspective view showing the state in which the extendable brace is extended and placed between the legs, starting from the state in Figure 3. [Figure 5] This perspective view shows the state in which the tabletop is in its highest position by extending the column base from the state in Figure 4. [Figure 6] This is a front view showing the expansion joint that makes up the expansion brace, with the outer and inner tubes separated. [Figure 7] This is a cross-sectional view of the expansion joint that makes up the expansion brace, showing a portion of it broken while the outer and inner tubes are separated. [Figure 8] This is a cross-sectional view showing the state in which the locking pin is locked to the locking part, relating to the operation of the expansion joint that constitutes the expansion brace. [Figure 9] This is a cross-sectional view showing the locking member inserted into the locking hole, relating to the operation of the expansion joint that constitutes the expansion brace. [Figure 10] This is a front view illustrating the folding mechanism of the legs relative to the tabletop, specifically the front-folding and rear-folding legs. [Figure 11] This is a front view showing the workbench with the legs folded in a closed position on the tabletop. [Figure 12] This is a front view showing the function of the workbench, with the legs positioned on the floor in an open-legged position from the tabletop. [Figure 13] This is a front view showing the operation of the workbench, specifically the state when the telescopic brace is moved from the retracted position to the extended position with the tabletop in its lowest position. [Figure 14] This is a front view showing the operation of the workbench with the tabletop in its lowest position and the telescopic brace stretched between the legs. [Figure 15] This is a front view showing the workbench in its highest position with the telescopic brace stretched between the legs. [Modes for carrying out the invention]

[0027] Preferred embodiments of the present invention will be described in detail below with reference to the drawings.

[0028] (Basic configuration) As shown in Figures 2 to 5, a first leg 12L and a second leg 12R are arranged spaced apart to the left and right (in the direction of the beam of the tabletop) on the underside of the rectangular tabletop 11 that forms the work surface. Each is pivotally connected via a pivot 13 so as to be able to change position between a closed-leg position Q1 (see Figure 11) along the underside of the tabletop 11 and an open-leg position Q2 (see Figure 12) suspended from the tabletop 11, thereby providing a foldable workbench. However, the present invention is not intended to be a foldable workbench structure and is not limited to the configuration of the illustrated embodiment.

[0029] The first leg body 12L and the second leg body 12R each form a frame-like structure by connecting a pair of column legs 14, which are spaced apart in the front-to-back (gable direction of the top plate) directions, with a horizontal bar. Each column leg 14 is formed by an extendable leg in which an upper outer tube 14a and a lower inner tube 14b, which are pivotally connected to the pivot portion 13, are fitted together in an extendable and retractable manner and can be fixed in a predetermined extended or retracted length. A caster 15 is provided at the lower end of the inner tube 14b.

[0030] Between the front and rear column bases 14, the lower end of the outer tube 14a is connected by a first crossbar 16, the lower end of the inner tube 14b is connected by a second crossbar 17, and furthermore, the portion of the outer tube 14a above the first crossbar 16 is connected by a third crossbar 18.

[0031] The third crossbar 18 is provided with a foldable brace 19. Both ends of the foldable brace 19 are pivotally connected to the third crossbar 18 and the underside of the top plate 1 via brackets. By folding the foldable brace 19 toward the pivot 13, the legs 12L and 12R can be rotated toward the closed leg position Q1, and by unfolding it in a straight line, the legs 12L and 12R can be rotated toward the open leg position.

[0032] With the first leg 12L and the second leg 12R in the open-leg position, Figure 2(A) shows the column base 14, which is made of telescopic tubes, contracted to its shortest length, and therefore the top plate 11 is in the lowest position P1. Figure 2(B) shows the column base 14 extended to its longest length, and therefore the top plate 11 is in the highest position P2. Of course, in order to allow heights between the two positions P1 and P2, the length of the column base 14 is configured to be selectable in stages, and although not shown in the figure, a locking mechanism is provided to fix the outer tube 14a and inner tube 14b in a non-extendable position when they are set to a predetermined length. Such a locking mechanism can be configured in the same way as in the prior art.

[0033] By the way, in the split-leg position Q2, the first leg body 12L and the second leg body 12R are configured such that an extendable brace 20 is stretched between the first crossbar 16 of one leg body and the second crossbar 17 of the other leg body.

[0034] The telescopic brace 20 is formed by a telescopic tube that allows the outer tube 20a and the inner tube 20b to be fitted together in an expandable and contractible manner and can be fixed in a predetermined expanded and contracted length. The tail end of the telescopic tube (the end of the inner tube 20b in the illustrated embodiment) is pivotally connected to a pivot portion 21 provided on the first crossbar 16 so as to be able to rotate vertically, and a hook means 22 is provided at the tip end (the end of the outer tube 20a in the illustrated embodiment) for rotatably gripping the second crossbar 17.

[0035] The telescopic brace 20 is configured such that, when contracted to its shortest length and rotated upright from the pivot 21, its length does not exceed the upper end of the outer tube 14a of the column base 14 (see Figures 2(A) and 3). Therefore, the third crossbar 18 is provided with a holding means 23 that holds the upright and rotated telescopic brace 20 in a position approximately parallel to the column base 14. The holding means 23 is preferably composed of leaf springs that spring into both sides of the outer tube 14a, which allows for one-touch holding and release of the outer tube 14a by pushing it in and pulling it out.

[0036] As a result, as shown by the dashed line in Figure 2(A), the telescopic brace 20 rotates downward from a state in which it is held upright on the first crossbar 16 of one leg between the first leg body 12L and the second leg body 12R, and then extends and rotates toward the second crossbar 17 of the other leg body, as shown by the solid line, and is pivotally connected between the first crossbar 26 and the second crossbar 17 in an interposed state by the hook means 22 which rotatably grips the second crossbar 17.

[0037] Therefore, as shown in Figure 2(B), when the column base 14 is extended to raise the top plate 11 from the lowest position P1 to the highest position P2, the telescopic brace 20 also rotates and extends in accordance with this extension. Conversely, when the column base 14 is retracted to lower the top plate 11, the telescopic brace 20 also rotates and retracts in accordance with this extension.

[0038] When the top plate 11 is set to a predetermined height for use in work at height, the column base 14 (outer tube 14a and inner tube 14b) is fixed in a way that prevents extension or retraction by a fixing locking mechanism (not shown in the figure), and the telescopic brace 20 (outer tube 20a and inner tube 20b) is fixed in a way that prevents extension or retraction by screwing in a locking member (described later). In this state, the hook mechanism 22 engages with the upper surface and both sides of the second crossbar 17.

[0039] By the way, as shown in Figure 2(B), for example, when moving a workbench on the floor via casters 15 to the work site, the worker grips and pushes the column base 14, so in such a case, a lateral external force F acts toward the inside of the column base 14.

[0040] In response to such external forces F, the telescopic brace 20 is interposed between the first leg body 12L and the second leg body 12R, providing bracing support between the first crossbar 16 on the column base 14 of one leg body and the second crossbar 17 on the column base 14 of the other leg body. In other words, the telescopic brace 20 is stretched in an X shape across four points: the overlapping portion 14x of the outer tube 14a and inner tube 14b of the extended column base 14, and the lower end portion of the inner tube 14b extending downward from the portion 14x, thus forming a highly rigid reinforcement support structure. In this case, as shown in the figure, even when the top plate 11 is in its highest position P2, the telescopic brace 20 is not tilted as much as in the conventional technology, as indicated by the angle θ, so it can effectively resist horizontal external forces F.

[0041] In particular, in the conventional technology (see Figure 1(A)), the overlapping portion 4x of the inner and outer pipes forms a weak point, whereas in the embodiment of the present invention, the overlapping portion 14x is reinforced and supported by an expandable brace 20 that braces and supports the first horizontal bar 16 and the second horizontal bar 17 of the other column base 14, and thus resists external forces F, so there is no risk of distortion deformation.

[0042] (Structure of the expandable brace) Figures 6 to 9 show preferred embodiments of the telescopic brace 20. As described above, the telescopic brace 20 is constructed as an expandable tube by slidably inserting an inner tube 20b into an outer tube 20a provided with a hook means 23 at its tip, and is pivotally connected to the pivot portion 21 of the first crossbar 16 via a pivot hole 24 of a fixing member fixed to the tail end of the inner tube 20b.

[0043] As shown in the figure, the outer tube 20a and the inner tube 20b are provided with a locking mechanism 25 for fixing both tubes 20a and 20b when the expansion joint is at a predetermined expansion length, and a locking mechanism 26 for locking both tubes 20a and 20b when the expansion joint is at its shortest contracted length.

[0044] (Locking mechanism) The locking mechanism 25 comprises a locking member 27 located at the end of the outer tube 20a in the opposing direction and screwable into the tube, and a plurality of locking holes 28 located near the end of the inner tube 20b in the opposing direction and arranged in a row in the expansion / contraction direction (insertion direction).

[0045] The locking member 27 is composed of a shaft member 31 inserted through a nut 30 fixed to a fixing fitting 29 provided at the tip of the outer tube 20a. As shown in Figures 8 and 9, the shaft member 31 has a spring 33 made of a coil spring interposed between a knob 32 provided at the tail end and the fixing fitting 29. Normally, the tip of the shaft member 31 is biased in a direction that retracts it from the inside of the outer tube 20a. However, when the shaft member 31 is advanced against the spring 33, the male threaded portion 31a of the shaft member 31 is screwed into the nut 30. Therefore, when rotated via the knob 32, the male threaded portion 31a is screwed in, causing the head 31b at the tip of the shaft member 31 to advance into the inside of the outer tube 20a.

[0046] In contrast, the inner tube 20b has a groove 20c facing the fixing bracket 29, and the locking holes 28 are arranged in a row on a strip-shaped plate member located near the tip of the inner tube 20b and fixed along the groove 20c.

[0047] The locking mechanism 25 allows the outer tube 20a and inner tube 20b to slide against each other, and when the telescopic brace 20 is extended to a predetermined length, as shown in Figure 9, the locking member 27 is pushed in and rotated, causing the tip of the shaft member 31 to fit into a predetermined locking hole 28, thereby fixing and locking both tubes 20a and 20b together.

[0048] From this state, by reversing the locking member 27, the male screw portion 31a is released from the nut 30, and the spring 33 retracts it from inside the outer tube 20a, holding the head 31b in a waiting state with elastic contact with the nut 30. This makes it possible to slide the outer tube 20a and the inner tube 20b relative to each other in the expansion and contraction directions.

[0049] (locking mechanism) The locking mechanism 26 consists of a locking pin 34 provided on a fixing fitting 29 provided at the tip of the outer tube 20a, and a locking portion 35 provided near the tail end of the inner tube 20b.

[0050] Normally, the locking pin 34 is biased to move forward toward the inside of the outer tube 20a by a spring 36 made of a coil spring, and its tip 34a is inserted into the inside of the outer tube 20a. However, by pulling the knob 37 at the tail end, the tip 34a is retracted against the spring 36, causing it to move backward.

[0051] The locking portion 35 is formed by a recess created by bending a plate member fixed along the groove portion 20c of the inner tube 20b, and the plate member has a tapered surface 38 adjacent to the locking portion 35. The tapered surface 38 is formed by bending the plate member so that it slopes from the opening edge of the recess constituting the locking portion 35 toward the bottom of the groove portion 20c, toward the tip of the inner tube 20b.

[0052] When the telescopic brace 20 is brought to its shortest contracted length by sliding the outer tube 20a and the inner tube 20b relative to each other, the locking mechanism 26 pushes up the tip 34a of the locking pin 34 against the spring 36 with the tapered surface 38, and as soon as the locked portion 35 comes into contact with the tip 34a, the spring 36 advances the locking pin 34, thereby locking the tip 34a to the locked portion 35, thereby locking and holding both tubes 20a and 20b together, as shown in Figure 8.

[0053] From this state, pulling the knob 37 causes the locking pin 34 to retract against the spring 36, which in turn causes the tip 34a to move away from the locked portion 35, releasing the lock. This makes it possible to slide the outer tube 20a and the inner tube 20b relative to each other in the extension direction.

[0054] (Opening, closing, and extending of the legs on the workbench) As described above, the workbench is pivotally connected to the tabletop 11 such that the first leg 12L and the second leg 12R can freely change their position between a closed-leg position Q1 and an open-leg position Q2. As shown in Figure 10, the operation to change the position can be easily performed with the tabletop 11 placed on the floor. At this time, the telescopic brace 20 is held by the holding means 23 to each of the leg bodies 12L and 12R, and therefore the leg bodies 12L and 12R are rotated integrally with the telescopic brace 20 via the bending and unfolding of the bending brace 19.

[0055] As shown in Figures 10 and 11, when the first leg 12L and the second leg 12R are in the closed leg position Q1, one leg (the first leg 12L in the illustrated embodiment) is configured as a front-folding leg 12X and the other leg (the second leg 12R in the illustrated embodiment) is configured as a rear-folding leg 12Y, in order to enable a compact folded state of the workbench by aligning them parallel to the top plate 11.

[0056] Therefore, regarding the distance between the top plate 11 and the pivot part 13, a short distance H1 is set for the front-folding leg 12X, and a long distance H2 is set for the rear-folding leg 12Y. Initially, the front-folding leg 12X is placed in the closed leg position Q1, and the leg body 12L and the telescopic brace 20 are positioned parallel to the underside of the top surface 11 in close proximity. In this state, the leg body 12L is held by the leg holding bracket 38x.

[0057] Next, the rear-folding leg 12Y is placed in the closed-leg position Q1, and the leg body 12R and the telescopic brace 20 are placed on top of the front-folding leg 12X, which was previously placed in the closed-leg position, and positioned parallel to each other in close proximity. In this state, the leg body 12R is held in place by the leg retaining bracket 38y.

[0058] When the workbench is used for working at height, the casters 15 are placed on the floor surface as shown in Figure 12, with the first leg 12L and the second leg 12R in the open leg position Q2. At this time, the telescopic brace 20 is held upright from the pivot 21 and supported by the holding means 23 to the first leg 12L and the second leg 12R.

[0059] Next, as shown in Figures 13 and 14, the telescopic braces 20, 20 held by the first leg body 12L and the second leg body 12R are released from the holding means 23 and rotated downward around the pivot 21 as a fulcrum. At this time, as described above, the locking mechanism 26 is locked, so by releasing the lock, the outer tube 20a is extended from the inner tube 20b, and the hook means 22 at the tip of the outer tube 20a grips the second crossbar 17 of the other leg body 12.

[0060] As shown in Figures 14 and 15, with the telescopic braces 20, 20 stretched between the first leg 12L and the second leg 12R, when the column base 14 is extended to raise the top plate 11 from the lowest position P1 to the highest position P2, the telescopic braces 20 also extend while rotating in accordance with this movement. Conversely, when the column base 14 is retracted to lower the top plate 11, the telescopic braces 20 also retract while rotating in accordance with this movement.

[0061] Therefore, the top plate 11 is set to a desired height suitable for working at height, and the outer tube 14a and inner tube 14b of the column base 14 are fixed in place so as not to extend or retract using a fixing locking mechanism (not shown). The extension brace 20 is also fixed in place so as not to extend or retract by screwing in the locking member 27 of the locking mechanism 25, thereby fixing and locking the outer tube 20a and inner tube 20b. In this state, the workbench is used for working at height. [Explanation of Symbols]

[0062] (Conventional technology) 1. Tabletop 2L 1st leg 2R 2nd leg body 3 Pivotal connection 3a Support member 4 Pillars 4a outer tube 4b Inner tube 4x The overlapping part of the outer tube and inner tube 5 casters 6. First crossbar 7. Bending brace 8. Second crossbar 9. Stretchable brace 9a outer tube 9b Inner tube (Embodiments of the present invention) 11 Top plate P1 Lowest position P2 Best posture 12L 1st leg 12R 2nd leg body 12X Folding Legs 12Y Rear folding legs Q1 Legs closed posture Q2 Leg-splitting position 13 Pivotal connection 14 Column base 14a outer tube 14b Inner tube 14x The part where the outer tube and inner tube overlap 15 casters 16. First crossbar 17. Second crossbar 18 Third crossbar 19. Bending brace 20 Stretchable braces 20a outer tube 20b inner tube 20c Groove 21 Cardinal Branch 22 Hooking means 23 Retention means 24 Pivot hole 25 Locking mechanism 26 Locking mechanism 27 Locking component 28 locking holes 29 Fixing brackets 30 nuts 31 Shaft member 31a Male threaded portion 31b Head 32. Thumb part 33 Springs 34 Locking pin 34a Tip 35 Locked part 36 Springs 37. Thumb part 38 Tapered surface 39x, 39y Leg support bracket

Claims

1. A workbench is configured such that a pair of telescopic braces (20,20) are stretched across the first leg (12L) and second leg (12R) on the underside of the top plate (11) that forms the work platform, with the first leg (12L) and second leg (12R) positioned spaced apart to the left and right, respectively, and each of the first and second leg (14) being constructed by connecting a pair of front and rear column legs with a crossbar, and each column leg (14) being constructed by an extendable leg in which an upper outer tube (14a) and a lower inner tube (14b) are fitted together in an extendable manner and can be fixed in a predetermined extended length, and a pair of extendable braces (20,20) are stretched across the first leg and the second leg. The crossbar is composed of a first crossbar (16) that connects the vicinity of the lower longitudinal end of the outer tube (14a) between a pair of front and rear column bases, and a second crossbar (17) that connects the vicinity of the lower end of the inner tube (14b). The workbench is characterized in that the pair of telescopic braces (20) are each formed by a telescopic tube in which an outer tube (20a) and an inner tube (20b) are fitted together in an expandable and contractible manner and can be fixed in a state at a predetermined telescopic length, and both ends of the telescopic tubes are connected in an interposed state between the first leg (12L) and the second leg (12R) by pivoting to the first crossbar (16) of one leg and the second crossbar (17) of the other leg, and are configured to provide bracing support between the first and second crossbars against external forces acting toward the inside of both legs.

2. The workbench according to claim 1, characterized in that the telescopic brace (20) formed by the telescopic tube is pivotally connected (21) at its tail end to the first crossbar (16) so as to be rotatable in the vertical direction, and a hook means (22) is provided at its tip for rotatably gripping the second crossbar (17).

3. The workbench according to claim 2, characterized in that the first and second legs are provided with holding means (23) that hold them in a position substantially parallel to the column base (14) when the respective telescopic braces are rotated upright from the first crossbar (16) with the telescopic braces set to a predetermined contracted length.

4. The expandable brace (20) formed by the aforementioned expandable tubes is provided with a locking member (27) that can be screwed into the tube at the end of the outer tube (20a) in the opposing direction with respect to the opposing direction of the outer tube and inner tube which are fitted together, and a plurality of locking holes (28) arranged in a row in the direction of expansion and contraction near the end of the inner tube (20b) in the opposing direction. The workbench according to claim 1, 2, or 3, characterized in that the outer tube and inner tube are fixed together by screwing the locking member (27) into the locking hole (28) while the outer tube and inner tube are at a predetermined extension length.

5. The telescopic brace (20) formed by the aforementioned telescopic tube has, with respect to the opposing directions of the outer tube and inner tube which are fitted together, a locking pin (34) elastically biased inward is provided at the tip of the outer tube (20a) in the opposing direction, and a locking portion (35) for locking the locking pin and a tapered surface (38) adjacent to the locking portion are provided near the tail end in the opposing direction of the inner tube (20b). The workbench according to claim 4, characterized in that when the outer tube and inner tube are moved relative to each other in the contraction direction so that the telescopic tube is the shortest contracted length, the tapered surface (38) pushes up the locking pin (34) against the elastic biasing force, and then, with the locked portion facing the locking pin, the locking pin (34) is locked to the locked portion (35) by the elastic biasing force.

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