Alarm device

Abstract

The present invention provides an alarm device to prevent workers from falling from the work platform. [Solution] The work platform comprises a fixing part (10a) provided on the edge side wall (4b) of the girder side edge (4) of the work platform, a switch device (12) housed in the fixing part, a foot rest member (11) positioned on the fixing part, and an alarm device (13) that emits an alarm signal when the switch device is switched from the OFF state to the ON state. The device is configured to be switched ON when the foot rest member (11) is subjected to a load and lowered, and the foot rest surface (48) of the foot rest member (11) is positioned lower than the edge tread surface (47) formed on the edge upper wall (4a) of the top plate.

Description

Technical Field

[0001] The present invention relates to an alarm device, and particularly to an alarm device provided to prevent an operator from accidentally stepping off the work floor and falling in a workbench or the like where high-altitude work is performed.

Background Art

[0002] Conventionally, for example, a portable workbench is configured such that the short side of a substantially rectangular top plate is the wife-side edge, the long side is the girder-side edge, and a pair of wife-side edges are supported by foldable ladder-shaped legs so as to perform high-altitude work on the top plate. At that time, handrails are erected at the four corners of the top plate, and a pair of handrails located at both ends of the long side of the top plate are connected to each other by a safety rod at a position above the girder-side edge. Thereby, it is possible to prevent an operator from accidentally stepping off the top plate and falling.

[0003] However, the safety rod is intended to allow an operator to sense danger by touch when the operator's body touches it, and does not have sufficient rigidity to withstand the operator's fall.

[0004] Therefore, for example, when an operator is wearing thick work clothes and does not sense touching the safety rod, there is a risk of falling while damaging the safety rod.

[0005] Therefore, the applicant has proposed an alarm device that provides a winding belt instead of the safety rod and generates an alarm when a predetermined tension is applied to the belt (Patent Documents 1 and 2).

[0006] However, when a predetermined tension is applied to the belt by the operator's body, at that moment, the operator's body balance is disrupted, such as leaning on the belt, so it is insufficient to prevent a fall.

Prior Art Documents

Patent Documents

[0007] [Patent Document 1] Japanese Patent Publication No. 2012-92618 [Patent Document 2] Japanese Patent Publication No. 2011-226149 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] To prevent workers from falling from the top platform, it is desirable to install an alarm device that is configured to detect when any part of a worker's foot extends beyond the side edge of the top platform and trigger an alarm.

[0009] However, in that case, there remains an unresolved issue regarding how to configure the alarm system to provide a more preferable solution.

[0010] For example, it is preferable that the alarm device is configured such that a foot-receiving member is provided above a switch device built into the fixed part, and when the foot-receiving member is stepped on, the switch device is turned ON and an alarm is issued. However, since a load equivalent to the weight of the worker acts on the foot-receiving member, there is a risk of damaging the switch device.

[0011] Furthermore, while an alarm is preferably an audible alarm, there is a risk of missing the alarm if the work site is a noisy environment. In this case, it is preferable to provide a means that allows the worker to sense the position of their feet by touch, in addition to the audible alarm.

[0012] Furthermore, it is preferable that the alarm device be designed to be retrofittable to the workbench, and this requires some ingenuity.

[0013] The object of this invention is to provide an alarm device that solves some or all of the above-mentioned problems. [Means for solving the problem]

[0014] Therefore, the means configured by the present invention is a workbench in which the short side of a substantially rectangular top plate is used as the gable edge and the long side is used as the beam edge, and a pair of gable edges are supported by legs, and the beam edge of the top plate is a workbench comprising an upper edge wall and an edge side wall bent downward from the upper wall, and a fixing member extending along the beam edge, a switch device built into the fixing member, a foot-receiving member including the switch device and positioned above the fixing member so as to be able to move up and down, and an alarm device that emits an alarm signal when the switch device is turned from an OFF state to an ON state, and the switch device is turned ON when the foot-receiving member is lowered under load, and the fixing member of the alarm unit is detachably attached to the edge side wall of the top plate.

[0015] Furthermore, the means configured in the present invention is a workbench in which the short side of a substantially rectangular top plate is used as the gable edge and the long side is used as the beam edge, and a pair of gable edges are supported by legs, the top plate having an edge upper wall extending along the beam edge and an edge side wall bent downward from the upper wall, and an alarm device is provided which includes a fixing part provided on the beam edge of the top plate, a switch device housed inside the fixing part, a foot-receiving member positioned on the fixing part and an alarm device that emits an alarm notification when the switch device is turned from the OFF state to the ON state, and the foot-receiving member has an upper surface formed The foot-receiving surface is configured to lower when a load is applied to it, and the switch device is equipped with an upward-facing operation button, which faces the lower surface of the foot-receiving member, and is configured to be in the OFF state by holding the operation button in a predetermined position when the foot-receiving member is not lowered, and is configured to be in the ON state by pressing the operation button from the predetermined position when the foot-receiving member has lowered, and in terms of position in the height direction, the foot-receiving surface of the foot-receiving member is positioned at a lower position with respect to the edge tread surface formed on the upper wall of the edge of the top plate.

[0016] In an embodiment of the present invention, the foot-receiving member is formed integrally with a pivot wall portion and an operating wall portion. The operating wall is supported so as to be able to move up and down by pivoting the end edge of the pivot wall portion near the upper edge wall of the top plate. The upper surface of the pivot wall portion forms the edge tread surface, and the foot-receiving surface is formed on the upper surface of the operating wall. The mechanism is configured such that when the operating wall is lowered, the operation button is pressed and the mechanism is turned ON. The foot-receiving surface formed on the upper surface of the operating wall is lower than the edge tread surface formed on the upper surface of the pivot wall portion.

[0017] Preferably, an alarm device is provided by detachably attaching an alarm unit to the girder side edge of the top plate, the alarm unit comprising a fixing member extending along the girder side edge of the top plate and a foot-receiving member extending along the fixing member, the fixing member integrally forming an upper open groove-shaped portion arranged along the edge side wall of the top plate and a lateral wall portion overlapping along the upper edge wall of the top plate, the switch device being housed in the groove-shaped portion, and the foot-receiving member having a pivot wall portion The operating wall portion is integrally formed with the fixing member, and with the operating wall portion closing the upper opening of the groove-shaped portion of the fixing member, the end edge of the pivot wall portion is pivotally supported on the tip edge of the lateral wall of the fixing member, thereby supporting the operating wall portion so that it can move up and down. The upper surface of the pivot wall portion, which is superimposed on the upper edge wall of the top plate via the lateral wall portion, forms the edge tread surface, and the upper surface of the operating wall portion forms a foot-receiving surface, configured so that the foot-receiving surface is lower than the edge tread surface.

[0018] In this case, it is preferable that the working wall portion of the foot-receiving member extends from the pivot wall portion via an inclined wall that slopes downward, and that the inclined wall and the upper surface of the working wall portion form a foot-receiving surface that is lower than the edge tread surface.

[0019] Another embodiment of the present invention provides a workbench in which a substantially rectangular tabletop has its short side as a gable edge and its long side as a beam edge, with a pair of gable edges supported by legs, the tabletop having an edge upper wall extending along the beam edge and an edge side wall bent downward from the upper wall, and an alarm unit comprising a fixing member attached to and fixed to the beam edge of the tabletop, a switch device housed in the fixing member, a foot-receiving member positioned on the fixing member, and an alarm device that emits an alarm notification when the switch device is switched from an OFF state to an ON state, the foot-receiving member being able to move up and down between a standby position P1 and an operating position P2, the switch device having an operation button that is OFF when the foot-receiving member is not lowered and ON when the foot-receiving member is lowered, and in terms of position in the height direction, the foot-receiving surface formed by the upper surface of the foot-receiving member is positioned lower than the edge tread surface formed by the edge upper wall of the tabletop. [Effects of the Invention]

[0020] According to the present invention, when a worker's feet extend beyond the side edge of the work platform, the alarm device detects this and issues an alarm, thereby preventing the worker from falling.

[0021] In this system, the alarm device is configured to turn on a switch when the foot-receiving surface of the foot-receiving member moves downward when a load is applied, and the foot-receiving surface of the foot-receiving member is positioned lower than the edge tread formed on the upper edge wall of the girder side edge. Therefore, when a worker approaches the girder side edge from the work platform and the soles of their feet move from the high edge tread to the lower foot-receiving surface, the soles of their feet descend towards the foot-receiving surface, and they feel the difference in height, so they can sense the risk of falling before the alarm device sounds an alarm. When the soles of the feet actually step on the foot-receiving surface, the alarm device sounds an alarm, prompting the worker to stop. [Brief explanation of the drawing]

[0022] [Figure 1] This is a perspective view showing a workbench equipped with an alarm device according to an embodiment of the present invention. [Figure 2] It is a perspective view showing the girder side edge portion of the top plate of the workbench, the fixing member, the step receiving member, the switch device, and the warning device in a disassembled state. [Figure 3] It is a perspective view showing an enlarged part of FIG. 2. [Figure 4] It is a longitudinal sectional view showing the girder side edge portion of the top plate of the workbench, the fixing member, the step receiving member, the switch device, and the warning device in a disassembled state. [Figure 5] The end portion of the fixing member and the warning device are shown. (A) is a perspective view showing the disassembled state, and (B) is a perspective view showing the state where the warning device is inserted into the end portion of the fixing member. [Figure 6] The fixing member and the switch device are shown. (A) is a perspective view showing the disassembled state, and (B) is a side view showing a part of the switch device in cross section. [Figure 7] It is a perspective view showing the fixing member and the step receiving member with the switch device installed therein in a disassembled state. [Figure 8] Regarding the fixing member and the step receiving member with the switch device installed therein, (A) is a cross-sectional view showing the state before the step receiving member is attached to the fixing member, and (B) is a cross-sectional view showing the state where the step receiving member is attached to the fixing member. [Figure 9] A first embodiment of the mounting device for attaching the fixing member to the edge side wall of the girder side edge portion on the top plate is shown. It is a perspective view showing the girder side edge portion, the fixing member, and the step receiving member in a disassembled state. [Figure 10] Regarding the first embodiment of the mounting device, (A) is a perspective view showing the relationship between the shaft member with a head, the outer hole and the inner hole of the fixing member, and the lateral hole of the edge side wall, (B) is a front view of the outer hole, (C) is a front view of the inner hole, and (D) is a front view of the lateral hole. [Figure 11] It is a cross-sectional view showing the shaft member with a head and the fixing member in a disassembled state. [Figure 12] It is a cross-sectional view showing the state when the shaft member with a head is inserted into the fixing member and the locking pin of the lateral wall of the fixing member is inserted into the upper hole of the edge upper wall in the girder side edge portion. [Figure 13] It is a cross-sectional view showing the state where the unit with the step receiving member assembled to the fixing member is attached to the girder side edge portion. [Figure 14] This is a cross-sectional view showing the state in which the headed shaft member is held in place by the fixed member without any looseness when the unit, in which the foot-receiving member is assembled to the fixed member, is removed from the girder side edge. [Figure 15] Regarding the second embodiment of the mounting device, (A) is a perspective view showing the relationship between the headed shaft member, the outer and inner holes of the fixing member, and the lateral holes of the edge side wall; (B) is a front view of the outer hole; (C) is a front view of the inner hole; and (D) is a front view of the lateral hole. [Figure 16] Regarding the operation of the headed shaft member, (A) is a cross-sectional view showing the headed shaft member inserted through the outer and inner holes of the fixing member, and (B) is a cross-sectional view showing the state in which the retaining mechanism is fixed to the shaft end. [Figure 17] This is a cross-sectional view showing a unit, in which a foot-receiving member is assembled to a fixed member, attached to the side edge of a girder. [Figure 18] This is a perspective view showing the alarm unit attached to the side edge of the beam on the top plate, illustrating the operation of the alarm device. [Figure 19] This is a cross-sectional view showing the operation in which the foot-receiving member is in a standby position where it is not receiving a load, and the switch device is in the OFF state. [Figure 20] This is a cross-sectional view showing the operation in which the foot-receiving member is in the operating position due to receiving a load, and the switch device is in the ON state. [Figure 21] This diagram shows a cross-sectional view of an alarm device according to another embodiment of the present invention, in which the foot-receiving member is in a standby position. [Figure 22] This is a cross-sectional view showing the state when the foot-receiving member is in the operating position, relating to another embodiment. [Modes for carrying out the invention]

[0023] Preferred embodiments of the present invention will be described below with reference to the drawings.

[0024] (Workbench) In the embodiment shown in Figure 1, the alarm device is implemented on a portable workbench 1. The workbench 1 has a substantially rectangular top plate 2 that provides a work surface, with the short sides serving as end edges 3 and the long sides serving as beam edges 4. A pair of end edges 3, 3 are supported by ladder-shaped legs 5A, 5B, allowing workers to perform work at heights on the top plate 2. The legs 5A, 5B are folded under the top plate 2 when the workbench is not in use.

[0025] In the illustrated example, handrails 6 are erected at the four corners of the top plate 2. The handrails 6, 6, which face each other, are connected by safety rods 7 above the girder side edge 4 and by short safety rods 8 above the end side edge 3. This prevents workers from slipping off the top plate and falling. This is similar to known workbenches.

[0026] As shown in Figure 2, the girder-side edge 4 of the top plate 2 comprises an upper edge wall 4a extending along the girder-side edge and a side edge wall 4b that is bent downward from the upper edge wall 4a.

[0027] Therefore, an alarm device 9 is provided on the girder-side edge 4 of the top plate 2, and is configured to emit an alarm signal when the feet of a worker performing work on the top plate extend beyond the girder-side edge 4. A buzzer that emits an alarm sound is preferred as the alarm signal, but a lighting device that emits light or a vibrator that emits vibrations may also be used, as long as it can be perceived by the worker's five senses.

[0028] By the way, although the illustrated embodiment shows an example in which the alarm device 9 is installed on the top plate 2 of the workbench 1, the alarm device 9 can be installed not only on a workbench but also on various work platforms for working at heights, and for example it may be attached to the end of a scaffolding board of a temporary scaffold.

[0029] (Alarm device) As shown in Figures 2 to 4, the alarm device 9 consists of a fixing member 10 that constitutes a fixed fixing part 10a extending along the girder side edge 4 of the top plate 1, a foot-receiving member 11 extending along the fixing member 10, a switch device 12, and an alarm device 13 that emits an alarm signal when the switch device 12 is turned from the OFF state to the ON state.

[0030] Although the internal structure of the alarm device 13 is not shown, it consists of a power supply means 13a consisting of a battery and a signal generating means 13b. The signal generating means 13b consists of a sound output means such as a buzzer or bell that outputs a signal sound and a drive circuit that drives the sound output means. In the illustrated embodiment, both the sound output means and the drive circuit are built into the signal generating means 13b. However, the alarm device 13 may be configured such that, for example, the power supply means 13a and the drive circuit of the signal generating means 13b are built into the alarm device 13, and the sound output means such as a buzzer or bell is separated from the alarm device 13 and mounted at a desired location on the workbench 1.

[0031] Therefore, the alarm device 9 shown in Figures 1 to 20 is configured as an alarm unit 9U that can be detachably attached to the beam-side edge 4 of the top plate 2 of the workbench 1 by assembling the fixing member 10, the foot-receiving member 11, the switch device 12, and the alarm device 13. In other words, the alarm unit 9U is designed to be retrofittable to the workbench 1. In the case of the workbench 1 shown in the figure, the upper wall 4a of the edge is provided with upper holes 14 spaced apart in the longitudinal direction, and the side wall 4b of the edge is formed with lateral holes 15 spaced apart in the longitudinal direction, so the device can be attached by utilizing these holes. In addition, in the illustrated embodiment, the top plate 2 has a raised upper wall 4a of the edge, and a groove-shaped step portion 4c is formed on the side of the upper wall 4a of the edge (opposite the side wall 4b of the edge). Therefore, the device is designed to effectively utilize this step portion 4c for attachment.

[0032] (Fixing member) The fixing member 10 is formed from a molded material made by extruding a metal such as aluminum, and integrally forms an upper open groove-shaped portion 16 that is positioned along the edge side wall 4b of the top plate 2, and a horizontal wall portion 17 that is superimposed along the edge upper wall 4b of the top plate 2.

[0033] As shown in Figure 4, the groove-shaped section 16 has a pair of side walls 16b and 16c rising from the bottom wall 16a of the groove, and lip sections 18 and 18 facing each other are provided from both side walls 16b and 16c facing the upper opening, with receiving pieces 19 and 19 arranged below the lip sections 18 and 18. In this case, a narrow guide groove 20 is formed between the side wall 16c which is connected to the lateral wall section 17 and the lip section 18.

[0034] The bottom wall 14a is provided with a low rib 16d that rises from the center in the groove width direction, and through holes 21, 21 are provided on both sides of the rib 16d and penetrate the bottom wall 16a. Furthermore, an outer hole 22 is provided in the outer side wall 16b (the side wall furthest from the edge side wall 4b), and an inner hole 23 is provided in the inner side wall 16c (the side wall closer to the edge side wall 4b), with both holes 22, 23 arranged on the same axis.

[0035] As will be described in more detail later, the fixing member 10 is configured to be attached by inserting the shaft portion 24b extending from the head a of the headed shaft member 24 through the outer hole 22 and the inner hole 23, inserting the insertion end of the shaft portion 24b into the lateral hole 15 of the edge side wall 4b, and fixing the retaining means 25.

[0036] The horizontal wall portion 17 has a flat plate portion 17a that overlaps with the edge upper wall 4a when the inner side wall 16c of the groove-shaped portion 16 is aligned with the edge side wall 4b of the top plate 2, and a groove-shaped rail portion 17b that fits into the stepped portion 4c, and the groove portion of the rail portion 17b forms a pivot support portion 26.

[0037] The flat plate portion 17a is configured such that a locking pin 28 is fixed to it by a screw 27 inserted through a through hole 27a, and is suspended from the lower surface of the flat plate portion 17a, and the locking pin 28 is inserted into and locked into the upper hole 14 of the upper wall 4a of the edge portion.

[0038] (Foot-receiving member) The foot-receiving member 11 is formed from a molded material made by extruding a metal such as aluminum, and has a pivot wall portion 29 and an operating wall portion 30 integrally formed. With the operating wall portion 30 closing the upper opening of the groove-shaped portion 16 of the fixed member 10, the operating wall portion 30 is pivotally supported on the pivot receiving portion 26 of the lateral wall portion 17 of the fixed member 10, thereby supporting the operating wall portion 30 so that it can move up and down.

[0039] As will be described in more detail later, the pivot wall portion 29 is provided with a shaft piece portion 31 that is rotatably fitted inside the pivot receiving portion 26, and the foot receiving member 11 is supported so as to be swingable or rotatable around the shaft piece portion 31.

[0040] As shown in the figure, the working wall portion 30 extends from the pivot wall portion 29 via an inclined wall 30a that slopes downward, and a pushing portion 32 is provided on the lower side of the working wall portion 30, and locking portions 32a extend from both sides of the pushing portion 32, which are inserted between the lip portion 18 and the receiving piece 19 that are located at the opening of the fixing member 10 and are positioned vertically. Furthermore, a guide piece 33 is provided projecting from the lower side of the inclined wall 30a, which is slidably inserted into the guide groove 20 of the fixing member 10.

[0041] Therefore, the foot-receiving member 11 is assembled to the fixing member 10 by aligning the end of the molded material on which the fixing member 10 is formed with the end of the molded material on which the foot-receiving member 11 is formed, inserting the shaft piece 31 into the pivot support portion 26 from the side, inserting the guide piece 33 into the guide groove 20, inserting the locking portion 32a below the lip portion 18, and sliding it in the longitudinal direction.

[0042] (Alarm) The alarm device 13 has a housing 34 equipped with a flange 34a, and the power supply means 13a is housed inside the housing 34. As shown in Figure 5, the housing 34 is inserted into the grooved portion 16 from the longitudinal end of the fixing member 10, and the flange 3a is fixed to the end face of the grooved portion 16 with screws or the like, thereby closing the grooved portion 16 from the side.

[0043] As described above, it is preferable to house a signal generating means 13b in the housing 34 in addition to the power supply means 13a that constitutes the alarm 13. In this case, since the signal generating means 13b is composed of a sound output means such as a buzzer or a bell and a drive circuit that drives the sound output means, both the sound output means and the drive circuit may be housed in the housing 34, or only the drive circuit may be housed in the housing 34, and the sound output means such as a buzzer or a bell may be placed outside the housing 34 and attached to a desired location on the workbench 1 via wiring or the like.

[0044] (Switching device) As shown in Figure 6(B), the switch device 12 is provided with an operating button 36 that protrudes upward from the casing 35, and a commercially available tact switch can be used. Inside, for example, there is a disc spring 37b that turns the contacts of the printed circuit board 37a ON / OFF, and a pressing means 37c for pressing it. Therefore, when the operating button 36 is pressed down from the illustrated state, the disc spring 37b, deformed by the pressing means 37c, makes the contacts conductive, and the device is set to the ON state. When the operating button 36 is released from the pressing force, the disc spring 37b returns to its original state, and the device is set to the OFF state.

[0045] The switch device 12 is installed inside the groove-shaped portion 16 of the fixing member 10, and the operation button 36 is positioned in the upper opening of the groove-shaped portion 16 so that it faces the lower surface of the operating wall portion 30 of the foot-receiving member 11. When the foot-receiving member 11 is not under load, the operation button 36 is held in a predetermined position to be in the OFF state, and when the foot-receiving member 11 is under load and the operating wall portion 30 is lowered, the operation button 36 is pressed down from the predetermined position to be in the ON state.

[0046] As shown in Figures 6 to 8, the switch device 12 is inserted into the grooved portion 16 by inserting it from the end of the molded material on which the fixing member 10 is formed. With the casing 35 inserted into the space above the rib 16d of the grooved portion 16, it is positioned directly above the location where the insertion hole 21 is provided in the bottom wall 16a of the grooved portion 16, and is supported from below by the elastic buffer 38.

[0047] In the illustrated embodiment, the elastic cushioning means 38 is composed of a pair of compression coil springs 38a arranged on both sides of the rib 16d, and lifts the casing 35 to a position above the rib 16d, supporting the casing 35 in contact with the receiving pieces 19, 19 of the fixing member 10.

[0048] As shown in the figure, the bottom wall 16a of the groove-shaped portion 16 of the switch device 12 forms a support wall 39 that is spaced apart below the casing 36 of the casing 36, and a coil spring 38a that is compressible and resilient is interposed between the support wall 39 and the bottom of the casing 36.

[0049] In this case, it is preferable to provide a guide pin 40 that guides the coil spring 38a in the axial direction. As shown in Figure 8(A), the guide pin 40 is inserted from below into an insertion hole 21 provided in the bottom wall 16a that constitutes the support wall 39, and the coil spring 38a is inserted through it inside the groove-shaped portion 16, and the male threaded portion 41 provided at the tip is screwed into a female threaded portion 42 formed on the lower surface of the casing 35 to secure it.

[0050] As a result, as shown in Figure 8(B), the switch device 12 contacts the push portion 32 of the foot-receiving member 11 with the operation button 36 facing the upper opening of the groove-shaped portion 16, and holds the push portion 32 in an upward position. At this time, the foot-receiving member 11 is stopped in a state where upward movement is prevented by the locking portion 32a contacting the lower surface of the lip portion 18.

[0051] In this case, the foot-receiving member 11 rotates slightly around the shaft portion 31 from a horizontal position, as shown by the dashed line in the figure, to a position where the working wall portion 30 is tilted upward, which is the standby position P1. When a load is received from the worker stepping on it from this position, it rotates downward to an operating position P2 where it is almost horizontal. When the foot-receiving member 11 is in the standby position P1, the switch device 12 is in the OFF state by stopping the operation button 36 at a predetermined upward position, and when the foot-receiving member 11 is in the operating position P2, the operation button 36 of the switch device 12 is pressed and it is in the ON state. When the foot-receiving member 11 is in the operating position P2, it stops with the lower surface of the working wall portion 30 in contact with the upper surface of the lip portion 18, preventing it from moving downward, and supports the load from the worker stepping on it.

[0052] (Mounting device) The alarm unit 9U, assembled from the fixing member 10 to which the switch device 12 and alarm device 13 are attached, is fixed to the girder side edge 4 of the top plate 2 by inserting and locking the locking pin 28 into the upper hole 14 of the upper edge wall 4a, thereby fixing the lateral wall portion 17 of the fixing member 10, and the fixing member 10 is attached and fixed to the lateral hole 15 of the side wall 4b of the edge using the mounting device 43 described below.

[0053] (First embodiment of the mounting device) Figures 9 to 14 show a first embodiment of the mounting device 43.

[0054] The mounting device 43 is composed of the headed shaft member 24 described above, a retaining means 25, an outer hole 22 and an inner hole 23 provided in the groove-shaped portion 16 of the fixing member 10, and a lateral hole 15 in the girder side edge portion 4 of the top plate 2, and includes a coil spring 44 inserted between the side walls 16b and 16c of the groove-shaped portion 16.

[0055] In the first embodiment, as shown in Figure 11, a coil spring 44 is first inserted in a compressed state between the side walls 16b and 16c of the groove-shaped portion 16 of the fixing member 10, and held in a position concentrically or coaxially with the outer hole 22 and the inner hole 23.

[0056] Next, as shown in FIG. 12, the shaft portion 24b of the shaft member 24 with a head is inserted from the outer hole 22, passed through the coil spring 44, and the shaft end portion is inserted into the inner hole 23. In this state, the locking pin 28 of the lateral wall portion 17 of the fixing member 10 is inserted into the upper hole 14 of the edge upper wall 4a, and while lowering the fixing member 10, the shaft end portion of the shaft portion 24b is aligned with the horizontal hole 15 of the edge side wall 4b, and by pushing the shaft member 24 with a head, the shaft end portion of the shaft portion 24b is inserted through the horizontal hole 15. At this time, in the case of the illustrated embodiment, a neck portion 24c is provided between the head portion 24a and the shaft portion 24b of the shaft member 24 with a head, and the neck portion 24c abuts against the outer side wall 16b of the groove-shaped portion 16.

[0057] Thereafter, as shown in FIG. 13, inside the edge side wall 4b, a retaining means 25 formed of a pin is inserted into an insertion hole 45 formed in the diameter direction of the shaft end portion of the shaft portion 24b inserted from the horizontal hole 15.

[0058] In this way, by bringing the neck portion 24c of the shaft member 24 with a head into contact with the outer side wall 16b of the groove-shaped portion 16 and bringing the retaining means 25 into contact with the inner surface of the edge side wall 4b, the shaft member 24 with a head is held in a retaining state, and thereby, the fixing member 10 is attached and fixed to the girder side edge portion 4 of the top plate 2.

[0059] As shown in FIG. 10, the outer hole 22 is formed by a circular hole having an inner diameter D that allows the shaft portion 24b of the shaft member 24 with a head to pass through. On the other hand, the inner hole 23 and the horizontal hole 15 are formed with inner diameters D1 and D2 respectively defined by the minor diameter and the major diameter whose centers are orthogonal, such that D1 < D2, and in the case of the illustrated example, they are formed such that D = D1 < D2. And the axial length dimension L of the pin constituting the retaining means 25 is formed such that D < L ≦ D2 and is larger than the inner diameter DS of the coil spring 44, that is, it is formed such that DS < L.

[0060] With this configuration, when the shaft end of the shaft portion 24c of the headed shaft member 24 is inserted through the transverse hole 15 in the edge side wall 4b of the girder side edge 4 of the top plate 2, the retaining means 25 inserted into the insertion hole 45 is locked to the inner surface of the edge side wall 4b, with both ends of the pins constituting the retaining means 25 extending beyond the edge of the transverse hole 15, which has an inner diameter D1 on the shorter side. Therefore, in this state, the shaft portion 24c of the headed shaft member 24 cannot be removed from the transverse hole 15.

[0061] By the way, when the headed shaft member 24 is rotated 90 degrees around its axis, both ends of the pins constituting the retaining means 25 are positioned inside the edge of the longer inner diameter D2 of the horizontal hole 15, so the shaft portion 24c of the headed shaft member 24 can be removed from the horizontal hole 15 together with the retaining means 25. That is, by simultaneously removing the locking pin 28 from the upper hole 14, the alarm unit 9U of the alarm device 9 can be removed from the beam side edge 4 of the top plate 2 on the workbench 1.

[0062] For example, when transporting the workbench by folding it and loading it onto the bed of a truck, it is preferable to transport the alarm device 9 detached from the top plate 2 to prevent malfunction or damage to the alarm. However, when the alarm device 9 is detached, the headed shaft member 24 may rattle and generate abnormal noises. Therefore, in the first embodiment, the spring 44 is configured to operate as follows.

[0063] When the shaft portion 24c of the shaft member 24 with a head is removed from the lateral hole 15 as described above, the pins constituting the retaining means 25 are positioned such that both ends are inside the hole edge of the longer inner diameter D2 of the inner hole 23 in the side wall 16c of the groove-shaped portion 16, and it becomes possible to pass through the inner hole 23. Therefore, when the shaft member 24 with a head is moved in the extraction direction, the retaining means 25 passes through the inner hole 23 and moves inside the groove-shaped portion 16, compressing the coil spring 44. When the shaft member 24 with a head is rotated 90 degrees around the axis from this state, as shown in FIG. 14, both ends of the pin constituting the retaining means 25 abut against the side wall 16b beyond the hole edge having the shorter inner diameter D1 of the inner hole 23. Both ends of the pin are elastically abutted against the side wall 16b by receiving the elastic force of the coil spring 44 as shown by the illustrated arrow. Therefore, the shaft member 24 with a head is held in a state where rattling does not occur.

[0064] (Second Embodiment of the Mounting Device) FIGS. 15 to 17 show a second embodiment of the mounting device 43.

[0065] The mounting device 43 includes a shaft member 24 with a head, a retaining means 25, outer holes 22 and inner holes 23 provided in the groove-shaped portion 16 of the fixing member 10, and a lateral hole 15 in the lateral edge portion 4 of the girder side of the top plate 2, and is provided with a coil spring 44 fitted between the side walls 16b and 16c of the groove-shaped portion 16. The retaining means 25 made of a pin is configured to be removably inserted into an insertion hole 45 provided at the shaft end of the shaft member 24 with a head. This point is the same as that of the first embodiment described above.

[0066] As a configuration different from the above-described first embodiment, in the case of the second embodiment, as shown in FIG. 15, the inner hole 23 is formed by a circular hole having an inner diameter D that allows the shaft portion 24b of the shaft member 24 with a head to pass through. On the other hand, the outer hole 22 and the lateral hole 15 are formed such that the inner diameters D1 and D2 defined by the minor diameter and the major diameter orthogonal to the center are such that D1 < D2. In the case of the illustrated example, they are formed such that D = D1 < D2. And the axial length dimension L of the pin constituting the retaining means 25 is formed such that D < L ≦ D2.

[0067] The shaft member 24 with a head is provided with a pushing piece 46 that protrudes in the diametrical direction of the shaft portion 24b at a position spaced a predetermined distance from the head portion 24c. The length L1 of the pushing piece 46 is formed such that D1 < L1 ≦ D2 with respect to the shorter inner diameter D1 and the longer inner diameter D2 of the outer hole 22, and moreover, it is formed to be larger than the inner diameter DS of the coil spring 44, that is, DS < L1.

[0068] Therefore, as shown in FIG. 16(A), when the shaft end portion of the shaft portion 24b of the shaft member 24 with a head is inserted from the outer hole 22 and inserted through the coil spring 44, the pushing piece 46 enters the inside of the groove portion 16 from the outer hole 22 and compresses the coil spring 44. In this state, while inserting the retaining means 25 into the insertion hole 45 at the shaft end portion of the shaft portion 24b inserted from the inner hole 23 and rotating the shaft member 24 with a head 90 degrees around the axis, as shown in FIG. 16(B), the pushing piece 46 is elastically contacted with the inner surface of the side wall 16b outside the groove portion 16.

[0069] In the case of the illustrated example, the outer hole 22 and the lateral hole 15 are respectively arranged such that one of the inner diameters D1 and D2 is arranged in the vertical direction and the other is arranged in the horizontal direction, and the pushing piece 46 and the retaining means 25 are arranged so as to be orthogonal to each other with respect to the shaft portion 24b. For this reason, regarding the rotation direction of the shaft member 24 with a head, by passing the outer hole 22 with the pushing piece 46 in a horizontal posture and inserting the shaft end portion of the shaft portion 24b from the inner hole 23, when the retaining means 25 is inserted into the insertion hole 45, the retaining means 25 is in a vertical posture.

[0070] Therefore, when the shaft member 24 with a head is rotated 90 degrees around the axis, the pushing piece 46 is in a vertical posture and is elastically contacted with the inner surface of the side wall 16b outside the groove portion 16, holding the shaft member 24 with a head in a state where it cannot be removed and there is no rattling.

[0071] In this state, the fixing member 10 can be easily attached and fixed to the horizontal hole 15 in the side wall 4b of the edge of the top plate 2. As described above, the retaining means 25 is in a sideways position so that it can enter the longer inner diameter D2 of the horizontal hole 15.

[0072] Therefore, as shown in Figure 17, when the locking pin 28 of the lateral wall portion 17 of the fixing member 10 is inserted into the upper hole 14 of the edge upper wall 4a, and the fixing member 10 is lowered, the shaft end of the shaft portion 24b is aligned with the lateral hole 15 of the edge side wall 4b, and the headed shaft member 24 is pushed in, the retaining means 25 passes through the lateral hole 15. Consequently, when the headed shaft member 24 is rotated 90 degrees around its axis from that state, the retaining means 25 takes a vertical position and comes into contact with the inner surface of the edge side wall 4b. At this time, the compressed coil spring 44 provides an elastic biasing force in the pulling direction to the headed shaft member 24, so the retaining means 25 is elastically contacted with the edge side wall 4b without any looseness.

[0073] (Operation of the alarm system) Figures 18 to 20 show the operation of the alarm device 9 configured as described above. As shown in the figures, the alarm device 9 is mounted as an alarm unit 9U along the girder side edge 4 of the work floor portion 2A of the top plate 2, and is configured to sound an alarm when a worker's foot extends beyond the girder side edge 4 and steps on the foot rest 11.

[0074] In the illustrated embodiment, as shown in Figure 19, the upper surface of the girder side edge 4 forms a raised portion 4d that rises higher than the work floor portion 2A, as indicated by the reference numeral H1, and the edge upper wall 4a is formed to be at the same height as the raised portion 4d, forming a groove-shaped step portion 4c between the edge upper wall 4a and the raised portion 4d. The alarm device 9 is locked by passing the locking pin 28 of the flat plate portion 17a of the lateral wall portion 17 of the fixing member 10 through the edge upper wall 4a, and fitting the groove-shaped rail portion 17b into the step portion 4c. This point is as described above.

[0075] Therefore, the foot-receiving member 11 supports the operating wall 30 so that it can move up and down by fitting the shaft piece 31 of the pivot wall 29 into the pivot receiving portion 26 of the lateral wall 17 and pivoting it. When the operating wall 30 moves downward, the push portion 32 presses the operation button 36 of the switch device 12, turning the switch device 12 ON and generating an alarm from the alarm device 13.

[0076] In this case, the foot-receiving member 11 has the operating wall portion 30 positioned at a lower location via an inclined wall 30a that slopes downward from the pivot wall portion 29, and as indicated by the reference numeral H2 in Figure 19, a height difference is formed between the pivot wall portion 29 and the operating wall portion 30. Therefore, in the illustrated embodiment, with respect to the position in the height direction, the highest edge tread surface 47 is formed above the upper edge wall 4a of the top plate 2 by the upper surface of the pivot wall portion 29, and a foot-receiving surface 48 that is lower than the edge tread surface 47 is formed by the inclined wall 30a and the upper surface of the operating wall portion 30.

[0077] Therefore, when a worker approaches the girder edge 4 from the work platform 2A, they first step on the edge tread 47 with the sole of their foot, allowing them to sense by touch that they have reached a dangerous area on the girder edge 4 where there is a risk of falling.

[0078] Furthermore, when stepping out of such a dangerous area, the sole of the foot descends towards the lower footing surface 48, which has a difference in height, allowing the worker to sense that they are in a truly dangerous situation. Therefore, this dual tactile sensation enables the worker to return to the work platform 2A before losing their footing.

[0079] Incidentally, when the edge tread 47 is stepped on by the stepping foot, as shown in Figure 20, the foot-receiving member 11 is moved down from the standby position P1 to the operating position P2, and the switch device 12 is turned ON, which causes the alarm device 13 to emit an alarm sound or the like, prompting the worker to stop. Since the edge tread 47 is formed on the upper edge wall 4a of the top plate, an alarm is issued before the worker's foot extends beyond the girder side edge 4, that is, before the danger becomes a reality, thus preventing falls early.

[0080] Then, when the worker's foot moves beyond the edge tread 47 and further steps on the foot-receiving surface 48, the foot-receiving member 11 is pressed down while remaining in the operating position P2, so the switch device 12 remains in the ON state and the alarm device 13 continues to emit an alarm.

[0081] In this process, the foot-receiving member 11 swings or pivots around the shaft portion 31 as a fulcrum, moving downward while sliding the arc-shaped guide piece 33 along the guide groove 20. The foot-receiving member 11 is then locked to the fixing member 10 via the guide piece 33 and the guide groove 20, and since the pushing portion 32 is fitted inside the upper opening of the groove-shaped portion 16, it will not detach from the fixing member 10 and fall off.

[0082] The foot-supporting member 11, when stepped on, contacts and is supported by the lip portion 18 of the groove-shaped portion 16 of the fixing member 10, thereby effectively supporting the load received from the soles of the worker's feet. In other words, by supporting the worker's weight, it prevents the worker from falling.

[0083] Incidentally, as mentioned above, when the foot-receiving member 11 moves downward from the standby position P1 to the operating position P2, the switch device 12 moves downward while following the push part 32 via the compression of the coil spring 38a that constitutes the elastic buffering means 38. For this reason, the operation button 36 is turned ON when pressed by the push part 32, but it does not receive a force stronger than the pressing force required to form the ON state, which has the advantage that there is no risk of damaging the switch device 12.

[0084] Then, upon receiving an alarm, when the worker returns their foot from the foot-receiving member 11 to the work floor 2A, the coil spring 38a constituting the elastic cushioning means 38 returns to its original position, causing the switch device 12 to move upward. This pushes up the push part 32 via the operation button 36, returning the foot-receiving member 11 to its standby position P1, as shown in Figure 19. At this time, the switch device 12 stops moving upward as the casing 35 comes into contact with the receiving piece 19, and since it does not receive a predetermined pressing force from the push part 32 of the foot-receiving member 11, it is set to the OFF state.

[0085] The coil spring 38a is compressed axially between the casing 35 and the support wall 39 and then elastically restored, but because the guide pin 40 is inserted through it, it does not deform in a direction deviated from the axial direction, and a predetermined posture is maintained.

[0086] Regarding the elastic support of the switch device 12 by the elastic buffering means 38, in the illustrated embodiment, a support wall 39 is formed on the bottom wall 4a of the groove-shaped portion 16 to support the coil spring 38a, but a support means 39 separate from the bottom wall 4a of the groove-shaped portion 16 may also be provided. For example, the casing 35 of the switch device 12 may be housed inside the housing so as to be vertically movable, and a unit may be formed in which the elastic buffering means 38 consisting of the coil spring 38a is interposed between the support means 39 formed by the bottom wall of the housing and the casing 35, and the housing may be mounted and fixed inside the groove-shaped portion 16.

[0087] (Another embodiment of the alarm device) Figures 21 and 22 show an alarm device according to another embodiment of the present invention. The girder-side edge 4 of the top plate 2 comprises an upper edge wall 4a extending along the girder-side edge and an edge side wall 4b bent downward from the upper edge wall 4a. This is the same as in the embodiment described above.

[0088] The alarm device 9 comprises a fixing member 10 extending along the girder side edge 4 of the top plate 1, a foot-receiving member 11 extending along the fixing member 10, a switch device 12, and an alarm device (not shown) that emits an alarm signal when the switch device 12 is switched from the OFF state to the ON state. This aspect is also the same as in the embodiment described above.

[0089] The fixing member 10 has an upper-opening groove-shaped portion 16 arranged along the edge side wall 4b, and houses a switch device 12 inside. An elastic buffering means 38 consisting of a coil spring 38a is interposed between the support wall 39 formed by the bottom wall 16a of the groove-shaped portion 16 and the casing 35 of the switch device 12, supporting the upper part of the casing 35 in contact with the receiving piece 19 of the groove-shaped portion 16. In this case, as in the embodiment described above, a guide pin 40 is provided to guide the coil spring 38a.

[0090] The foot-receiving member 11 is integrally formed with an operating wall portion 30 that covers the fixing member 10 from above and a pushing portion 32 that faces the upper opening of the groove-shaped portion 16, and a locking piece portion 32a extending laterally from the pushing portion 32 faces the lower side of lip portions 18, 18 that extend above the receiving piece 19 of the groove-shaped portion 16.

[0091] Therefore, as shown in Figure 21, the foot-receiving member 11 moves upward in accordance with the switch device 12 which is pushed up by the coil spring 38a, and stops moving upward when the locking piece 32a comes into contact with the lower surface of the lip portion 18, thereby maintaining the standby position P1. At this time, the upper surface of the working wall portion 30 forms the foot-receiving surface 48.

[0092] When a worker approaches the girder side edge 4 from the work platform 2A and steps on the foot-receiving surface 48 with the sole of their foot, the foot-receiving member 11 moves downward to the operating position P2, as shown in Figure 22. This causes the push part 32 to press the operation button 36 of the switch device 12, turning the switch device 12 ON and generating an alarm from the alarm device.

[0093] In this embodiment, the alarm unit 9U is fixed to the edge side wall 4b of the girder side edge 4 by a device similar to the mounting device 43 including the headed shaft member 24 described in the above embodiment, with the fixing member 10 attached to the edge side wall 4b of the girder side edge 4. At that time, as shown in Figure 21, the upper surface of the edge upper wall 4a of the girder side edge 4 is used as the edge tread surface 47, and the foot-receiving surface 48 formed by the upper surface of the working wall portion 30 of the foot-receiving member 11 is positioned at a lower position. In other words, as indicated by the reference numeral H3, a height difference is formed between the edge tread surface 47 and the foot-receiving surface 48.

[0094] Therefore, when a worker approaches the girder side edge 4 from the work platform 2A and the sole of their foot extends beyond the edge tread surface 47, the system detects the risk of falling as the foot descends towards the lower foot-receiving surface 48, which has a height difference. When the stepping foot touches the foot-receiving surface 48, the foot-receiving member 11 is lowered from the standby position P1 to the operating position P2, and the switch device 12 is turned ON, which generates an alarm such as an alarm sound from the alarm device 13, prompting the worker to stop.

[0095] In this regard, if the edge tread surface 47 and the foot-receiving surface 48 are positioned at the same height, the worker may step on the foot-receiving surface 48 without realizing that the sole of their foot has gone beyond the edge tread surface 47, and suddenly receive an alarm, which could cause a delay in their awareness of stopping. As a result, there is a risk of falling from the foot-receiving surface 48 (foot-receiving member 11) even after receiving the alarm.

[0096] In contrast, with the configuration that provides a height difference as described above, the worker receives an alarm immediately after sensing that the sole of their foot has gone beyond the edge tread surface 47, allowing them to stop on the foot-receiving surface 48 (foot-receiving member 11) and avoid falling. [Explanation of symbols]

[0097] 1 Workbench 2 Top plate 2A Working floor section 3. The wife's side edge 4-digit side edge 4a Upper wall of the edge 4b Edge side wall 4c Step section 4d ridge 5A, 5B Legs 6. Handrail 7, 8 Safety rod 9 Alarm device 9U Alarm Unit 10 Fixing member 10a Fixed part 11 Foot-receiving member P1 Standby position P2 Operating position 12 Switching device 13 Alarm 13a Power means 13b Signal generating means 14 Upper hole 15 Horizontal hole 16 Groove 16a Bottom wall of the trench 16b, 16c Side walls of the groove 16d Rib 17 Horizontal wall section 17a Flat plate part 17b Grooved rail section 18 Lip section 19 Receiver 20 guide grooves 21 Through hole 22 Outer hole 23 Inner hole 24 Headed shaft member 24a head 24b Shaft 24c neck 25 Retaining means 26 Pivot support section 27 Bis 27a through hole 28 Locking pin 29 Pivot wall 30 Working wall section 30a Slanted wall 31 Shaft piece 32 Pushing part 32a Locking part 33 Guide piece 34. Alarm housing 34a Flange 35 Switching device casing 36 operation buttons 37a Printed circuit board 37b Disc spring 37c Pressing means 38 Elastic cushioning means 38a Coil spring 39 Supporting wall (supporting means) 40 guide pins 41 Male screw part 42 Female thread section 43 Mounting device 44 Coil Springs 45 Insertion hole 46 Push piece 47 Edge tread 48 Tread surface

Claims

1. In a workbench, the short side of a roughly rectangular tabletop (2) is designated as the gable edge, the long side as the beam edge, and a pair of gable edges are supported by legs (5), and the beam edge (4) of the tabletop comprises an upper edge wall (4a) and an edge side wall (4b) that is bent downward from the upper wall, The alarm unit (9U) comprises a fixing member (10) extending along the girder side edge (4), a switch device (12) housed in the fixing member, a foot-receiving member (11) positioned above the fixing member so as to be vertically movable including the switch device, and an alarm device (13) that emits an alarm signal when the switch device is turned from the OFF state to the ON state, and the switch device is turned ON when the foot-receiving member (11) is subjected to a load and lowered. An alarm device characterized in that the fixing member (10) of the alarm unit (9U) is detachably attached to the edge side wall (4b) of the top plate.

2. In a workbench having a nearly rectangular tabletop with its short sides serving as gable edges and its long sides serving as beam edges, and a pair of gable edges supported by legs, the tabletop comprises an upper edge wall (4a) extending along the beam edge (4) and an edge side wall (4b) bent downward from the upper wall, The alarm device is provided, which includes a fixing part (10a) provided on the beam side edge (4b) of the top plate, a switch device (12) housed in the fixing part, a foot rest member (11) positioned on the fixing part, and an alarm device (13) that emits an alarm notification when the switch device is turned from the OFF state to the ON state. The foot-receiving member (11) is configured to descend when a load is applied to the foot-receiving surface (48) formed on its upper surface. The switch device (12) is equipped with an upward-facing operation button (36), and the operation button is positioned facing the lower surface of the foot-receiving member (11). When the foot-receiving member (11) is not lowered, the operation button is held in a predetermined position to be in the OFF state, and when the foot-receiving member (11) is lowered, the operation button is pressed down from the predetermined position to be in the ON state. The alarm device is characterized in that, with respect to its position in the height direction, the foot-receiving surface (48) of the foot-receiving member (11) is positioned lower than the edge tread surface (47) formed on the edge upper wall (4a) of the top plate.

3. The foot-receiving member (11) has a pivot wall portion (29) and an operating wall portion (30) formed integrally. The pivot wall portion (29) is pivotally supported near the upper edge wall (4a) of the top plate, thereby supporting the working wall portion (30) so that it can move up and down, and the upper surface of the pivot wall portion (29) forms the edge tread surface (47). By forming the foot-receiving surface (48) on the upper surface of the operating wall (30), the operating wall is configured to be turned ON when the operating button (36) is pressed when the operating wall is lowered. The alarm device according to claim 2, characterized in that the foot-receiving surface (48) formed on the upper surface of the operating wall (30) is lower than the edge tread surface (47) formed on the upper surface of the pivot wall portion (29).

4. An alarm device is provided by detachably attaching an alarm unit (9U) to the beam side edge (4) of the top plate. The alarm unit (9U) comprises a fixing member (10) extending along the girder side edge (4) of the top plate, and a foot-receiving member (11) extending along the fixing member. The fixing member (10) is integrally formed with an upper open groove-shaped portion (16) positioned along the edge side wall (4b) of the top plate and a horizontal wall portion (17) that overlaps along the upper edge wall (4a) of the top plate, and the switch device (12) is housed in the groove-shaped portion (16). The foot-receiving member (11) is formed integrally with a pivot wall portion (29) and an operating wall portion (30), and with the operating wall portion (30) closing the upper opening of the groove-shaped portion (16) of the fixed member, the operating wall portion (30) is pivotally supported on the tip edge of the lateral wall portion (17) of the fixed member, thereby supporting the operating wall portion (30) so that it can move up and down. The alarm device according to claim 3, characterized in that the upper surface of the pivot wall portion (29), which is superimposed on the upper edge wall (4a) of the top plate via the horizontal wall portion (17), forms the edge tread surface (47), and the upper surface of the operating wall portion (30) forms the foot receiving surface (48), and the foot receiving surface (48) is configured to be lower than the edge tread surface (47).

5. The alarm device according to claim 3 or 4, characterized in that the working wall portion (30) of the foot-receiving member (11) extends from the pivot wall portion (29) via an inclined wall (30a) that slopes downward, and the inclined wall (30a) and the upper surface of the working wall portion (30) form a foot-receiving surface (48) that is lower than the edge tread surface (47).

6. In a workbench, the short side of a nearly rectangular tabletop is designated as the gable edge, the long side as the beam edge, and a pair of gable edges are supported by legs, and the tabletop comprises an upper edge wall (4a) extending along the beam edge (4) and an edge side wall (4b) bent downward from the upper edge wall, An alarm unit (9U) is provided, which consists of a fixing member (10) attached and fixed to the girder side edge (4) of the top plate, a switch device (12) housed inside the fixing member, a foot-receiving member (11) positioned on the fixing member, and an alarm device (13) that emits an alarm notification when the switch device is turned from the OFF state to the ON state. The foot-receiving member (11) is capable of moving up and down between a standby position P1 and an operating position P2, and the switch device (12) is equipped with an operation button (36) that is OFF when the foot-receiving member is not lowered and ON when the foot-receiving member is lowered. The alarm device is characterized in that, with respect to its position in the height direction, the foot-receiving surface (48) formed by the upper surface of the foot-receiving member (11) is positioned lower than the edge tread surface (47) formed by the upper edge wall (4a) of the top plate.

Images