JP7462496B2 - Holder, hook detection unit including said holder, and hook detection method - Google Patents

Description

The present invention relates to a holder capable of suspending a hook attached to a fall prevention device, a hook detection unit equipped with the holder, and a hook detection method.

When working at heights at construction sites, factories, etc., fall protection devices (formerly known as safety belts) are used. For example, full harness-type fall protection devices generally have a pair of left and right shoulder belts, a chest belt that spans between them, a waist belt, a thigh belt, etc., and a lanyard that has a hook on one end and the other end that is connected via a shock absorber to the location on the back of the shoulder belts.

The hook at the end of the lanyard is for attaching the lanyard to a structure at the work site when it is in use, and when working at height, the worker attaches the hook to a structure at the work site and uses the lanyard as a lifeline. In addition, a holder is attached to the shoulder belt of the fall arrest device to allow the hook to hang from the side of the worker's body when the lanyard is not in use. The holder is for hanging and carrying the hook when the worker heads to a high-altitude work site.

One example of technology for detecting whether a worker has hooked the hook at the end of a lanyard to a structure at the work site when working at height is described in Patent No. 5822796, in which a concave mounting section is formed on the hook and a Hall element is installed in the mounting section, with a magnet installed in a position opposite to this (see paragraph [0026] and Figure 5). When the hook is hooked onto the hooked section, the Hall element comes close to the magnet, detecting that the hook has been hooked onto the hooked section.

In addition, a proposal has been made to equip the hook with multiple sensors and a communication device that transmits signals from each sensor to the outside.

In the above conventional configuration, a dedicated hook must be prepared, making it difficult to apply to existing fall prevention devices that have generic hooks attached. In addition, the above conventional devices (especially the latter ones) are very expensive.

On the other hand, in full harness-type fall arrest devices, a pair of lanyards are provided, one on the left and one on the right, and when the left lanyard is used when working at height (i.e., when the hook at the end of the left lanyard is hooked onto a structure at the work site), the hook at the end of the right lanyard is engaged with the corresponding holder. Conversely, when the right lanyard is used when working at height (i.e., when the hook at the end of the right lanyard is hooked onto a structure at the work site), the hook at the end of the left lanyard is engaged with the corresponding holder.

Therefore, even if the hook at the end of the lanyard does not directly detect whether it is hooked onto a structure when working at height, it is possible to ensure a certain degree of safety when working at height by detecting the presence or absence of the hook on the holder side.

The present invention was made in consideration of these conventional circumstances, and the problem that the present invention aims to solve is to make it possible to reliably detect the presence or absence of a hook on a fall prevention device with an inexpensive configuration. The present invention also aims to make it possible to reliably detect the presence or absence of a hook on a fall prevention device with an inexpensive configuration, and to detect abnormal conditions such as malfunctions. Furthermore, the present invention seeks to provide a holder, hook detection unit, and hook detection method that enable such inexpensive and reliable detection of the presence or absence of a hook.

The present invention is a holder capable of hanging a hook provided on a fall prevention device, and comprises a holder body that engages the hook so that it can be hung, first and second detection units that detect the presence or absence of the hook in the holder body , and an abnormality detection unit that detects abnormalities based on the detection results of the first and second detection units .

According to the present invention, when the hook of the fall arrest device is hung and engaged on the holder body, the presence or absence of the hook on the holder body is detected by two detection units, the first and second detection units. This makes it possible to reliably detect the presence or absence of the hook of the fall arrest device. Moreover, in this case, since a general-purpose hook can be used without the need for a dedicated hook, the device can be constructed at low cost. Furthermore, in this case, by providing the abnormality detection unit, it becomes possible to detect abnormalities based on the detection results of the first and second detection units.

In the present invention, the first detection unit is a means capable of detecting the load caused by the weight of the hook, and the second detection unit is a means capable of detecting that the hook is positioned in the engagement position relative to the holder body.

In this case, the first and second detection units detect different detection objects when detecting the presence or absence of a hook on the holder body, making it possible to more accurately detect the presence or absence of a hook on the fall arrest device.

In the present invention, the holder body includes a base that is attached to the side of the worker's body, and a slider that is slidably attached to the base and to which the hook can be engaged. The first detection unit is a means that can detect the movement of the slider when the hook is engaged with the slider, and the second detection unit is a means that can detect that the hook is located in the engaging position relative to the slider.

In this case, when the hook engages with the slider, the first detection unit detects the movement of the slider, and the second detection unit detects that the hook is in the engagement position relative to the slider. In other words, when engaging with the slider, it is detected that the hook is suspended and engaged with the slider, and that the hook is in the engagement position of the slider. This makes it possible to more reliably detect the presence or absence of the hook of the fall arrest device.

The present invention further includes an alarm unit that issues an alarm when an abnormality is detected by the abnormality detection unit.

In the present invention, the first or second detection unit is a means capable of detecting that an excessive load has been applied to the holder body.

In the present invention, the first or second detection unit is a means capable of detecting a detection target provided on the hook.

The hook detection system of the present invention is a hook detection system in a fall arrest device equipped with a hook and a holder on which the hook can be hung , and is equipped with first and second detection units which detect the presence or absence of the hook in the holder, and a controller which determines whether the state is normal or abnormal based on the detection results of the first and second detection units.

According to the present invention, when the hook of the fall prevention device is hung on the holder and engaged, the presence or absence of the hook on the holder is detected by two detection units, the first and second detection units. This makes it possible to reliably detect the presence or absence of the hook of the fall prevention device. Moreover, in this case, since a general-purpose hook can be used without preparing a dedicated hook, it can be constructed at low cost. Furthermore, in this case, the controller can determine whether the state is normal or abnormal based on the detection results of the first and second detection units. Also, in the present invention, the holder and the hook may each be constructed of a pair of left and right members, the first and second detection units may be provided on each holder, and the controller may detect the normal state or abnormal state based on the detection results of the first and second detection units of each holder.

The hook detection method according to the present invention is a hook detection method for detecting the presence or absence of a hook in a holder capable of suspending the hook of a fall arrest device. The holder has first and second detectors for detecting the presence or absence of the hook. The hook detection method includes the following steps (processes):
i) a hook presence detection step in which, when the hook is hung on the holder, the first detection unit outputs a first detection output and the second detection unit outputs a second detection output.
ii) a no-hook detection step in which, when the hook is removed from the holder, the first detection unit outputs a first' detection output having an output operation setting different from the first detection output, and the second detection unit outputs a second' detection output having an output operation setting different from the second detection output.
iii) An abnormality detection step of detecting an abnormality when the first detection unit outputs a first detection output and the second detection unit outputs a second' detection output, or when the first detection unit outputs the first' detection output and the second detection unit outputs a second detection output.

According to the present invention, in the hook presence detection step, when the hook of the fall prevention device is hung on the holder and engaged, the state of the holder having the hook is detected by two detection units, the first and second detection units. This makes it possible to reliably detect the presence of the hook of the fall prevention device. Moreover, in this case, it is possible to use a general-purpose hook without preparing a special hook, so that detection can be performed inexpensively.

Also, according to the present invention, in the no-hook detection step, when the hook of the fall arrest device is removed from the holder, the state where the hook is not on the holder is detected by two detection units, the first and second detection units. This makes it possible to reliably detect the absence of the hook of the fall arrest device. Moreover, in this case, since a general-purpose hook can be used without preparing a special hook, detection can be performed at low cost . Furthermore, according to the present invention, by providing the abnormality detection step, it becomes possible to detect an abnormality when the first detection unit outputs the first detection output and the second detection unit outputs the second' detection output, or when the first detection unit outputs the first' detection output and the second detection unit outputs the second detection output.

As described above, the present invention makes it possible to inexpensively and reliably detect the presence or absence of a hook on a fall prevention device.

This is an overall oblique view from the front of a full harness-type fall arrest device equipped with a holder according to one embodiment of the present invention, worn by a worker, with the left and right hooks hanging from each holder. FIG. 2 is an overall perspective view of the full harness type fall arrest device (FIG. 1) seen from the rear, showing the left hook removed from the holder. FIG. 2 is an overall perspective view of the holder (FIG. 1) as viewed from above on the right side. FIG. 2 is an overall perspective view of the holder (FIG. 1) as viewed from below on the right side. FIG. 2 is a front view of the holder (FIG. 1); FIG. 6 is a view taken along line VI in FIG. 5 . FIG. 7 is a view taken along line VII in FIG. 5 . FIG. 8 is a view taken along line VIII in FIG. 5 . FIG. 6 is a front view of the holder (FIG. 5) with the lid removed from the base, illustrating the internal structure. FIG. 4 is an overall perspective view of the holder (FIG. 3) with a cover removed from a base, illustrating the internal structure. FIG. 5 is an overall perspective view of the holder (FIG. 4) with a cover removed from a base, illustrating the internal structure. FIG. 4 is an overall perspective view showing a state in which a hook is suspended from a slider in the holder (FIG. 3). FIG. 5 is an overall perspective view showing a state in which a hook is suspended from a slider in the holder (FIG. 4). FIG. 13 is an overall perspective view of the holder (FIG. 12) as seen from above on the left side. FIG. 14 is an overall perspective view of the holder (FIG. 13) as seen from below on the left side. FIG. 6 is a front view showing a state in which a hook is suspended from a slider in the holder (FIG. 5). FIG. 17 is a view taken along line XVII in FIG. 16 . FIG. 18 is a view taken along line XVIII in FIG. 16 . 19 is a view taken along line XIX in FIG. 16 . FIG. 10 is a front view showing a state in which a hook is suspended from a slider in the holder (FIG. 9). FIG. 11 is an overall perspective view showing a state in which a hook is suspended from a slider in the holder (FIG. 10). FIG. 12 is an overall perspective view showing a state in which a hook is suspended from a slider in the holder (FIG. 11). FIG. 2 is a diagram showing an example of a schematic block configuration of the holder (FIG. 1); FIG. 2 is a diagram showing another example of a schematic block configuration of the holder (FIG. 1). 4 is a diagram for explaining an example of output operation settings of first and second detection units of the holder (FIG. 1). FIG. 10A and 10B are diagrams for explaining another example of output operation settings of the first and second detectors of the holder (FIG. 1). FIG. 6 is a partial front view showing a first modified example of the holder (FIG. 5). FIG. 6 is a partial front view showing a second modified example of the holder (FIG. 5). FIG. 7 is a partial front view showing a third modified example of the holder (FIG. 5). FIG. 7 is a partial front view showing a fourth modified example of the holder (FIG. 5). FIG. 7 is a partial front view showing a fifth modified example of the holder (FIG. 5). FIG. 7 is a partial front view showing a sixth modified example of the holder (FIG. 5). FIG. 13 is a front view showing a seventh modified example of the holder (FIGS. 5 and 9) with the lid removed from the base. 33A to 33C are diagrams for explaining the operation of the holder (FIG. 32). FIG. 13 is a front view showing an eighth modified example of the holder (FIGS. 5 and 9) with the lid removed from the base.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.
Figures 1 to 25 are figures for explaining a holder according to one embodiment of the present invention, where Figures 1 and 2 are overall oblique views of a full harness-type fall arrest device that uses the holder, Figures 3 to 8 are external views of the holder, Figures 9 to 11 are figures showing the internal structure of the holder, Figures 12 to 19 are external views showing the state in which a hook is suspended from the holder, Figures 20 to 22 are internal structure views showing the state in which a hook is suspended from the holder, Figures 23 and 23A are schematic block diagrams of the holder, and Figures 24 and 25 are figures for explaining the output operation settings of the first and second contacts of the holder.

1 and 2, the fall arrest device 1 includes a pair of left and right shoulder belts _10-1 , _10-2 that are hung around the body of a worker P, a chest belt 11 that connects the shoulder belts, a waist belt 12, a pair of left and right thigh belts _13-1 , _13-2 , and a pair of left and right lanyards _14-1 , _14-2 . Here, a double lanyard type device having two lanyards is taken as an example.

The lanyard _14-1 is composed of a strap _14-1S with a hook _14-1H attached to its tip, and similarly, the lanyard _14-2 is composed of a strap _14-2S with a hook _14-2H attached to its tip. On the back side of the fall arrest device 1 (see FIG. 2), a D-ring 15 is fixed to the intersection of each of the shoulder belts _10-1 , _10-2 , and a shock absorber 16 is engaged with the D-ring 15. The base ends of each of the lanyards _14-1 , _14-2 are attached to the shock absorbers 16.

On the front side of the fall arrest device 1 (see FIG. 1), the holders 2, 3 according to this embodiment are attached to the left and right shoulder belts _10.sub.1 , _10.sub.2 . Each holder 2, 3 has a belt loop (not shown) through which the corresponding shoulder belt _10.sub.1 , _10.sub.2 can be inserted, and is attached to the shoulder belts _10.sub.1 , _10.sub.2 in advance by inserting the shoulder belts _10.sub.1 , _10.sub.2 through these belt loops. Alternatively, the holders 2, 3 have hook-shaped or claw-shaped fasteners (not shown) through which the corresponding shoulder belts _10.sub.1 , _10.sub.2 can be fastened, for example, to the shoulder belts _10.sub.1 , 10.sub.2, and are attached to the shoulder belts 10.sub.1, _10.sub.2 afterward by fastening the shoulder belts _10.sub.1 , _10.sub.2 to these fasteners. In the latter case, the holders 2, 3 are detachable from the shoulder belts _10.sub.1 , _10.sub.2 . In addition, the holders 2 and 3 of this embodiment may have a structure that allows them to be engaged with a holder that is originally attached to a conventional fall arrest device.

The holder 2 is for retaining the hook 14 ₁ H at the end of the lanyard 14 ₁ so as to enable hanging, and similarly, the holder 3 is for retaining the hook 14 ₂ H at the end of the lanyard 14 ₂ so as to enable hanging.

The external structure of the holder (holder body) 2 will be described with reference to Figures 3 to 8. The holder (holder body) 3 has a similar structure, and therefore only the holder 2 will be described here.
As shown in these figures, the holder 2 has a base 20 that is attachable to the shoulder belt ₁₀₁ (i.e., attached to the side of the worker's body), and a slider 21 that is slidably attached to the base 20 and can be engaged with the hook _141H . Although not shown, the base 20 has an engagement tool or belt loop on its back side (the back side of the paper in FIG. 5) for attaching to the shoulder belt ₁₀₁ .

The base 20 is composed of a box-shaped sensor housing 20A that houses a sensor that is a first detection unit (described later) for detecting the presence or absence of the hook 14 ₁ H, and a lid 20B that covers the front opening of the sensor housing 20 A. The slider 21 is supported by the sensor housing 20A so as to be slidable in the vertical direction (vertical direction in FIG. 5 ).

As shown in FIG. 5, the slider 21 is a frame-shaped member having a hook hanging portion of a roughly pentagonal shape, and has an opening 21a in the center. The slider 21 has a pair of left and right vertical wall surfaces 21A extending in the vertical direction, a bottom wall surface 21B disposed at the bottom and extending in the left and right direction (left and right direction in the same figure), and a pair of left and right inclined surfaces 21C inclined downward so as to connect each vertical wall surface 21A and the bottom wall surface 21B. The opening 21a is defined by each of these vertical wall surfaces 21A, bottom wall surface 21B, and inclined surfaces 21C, and the bottom wall surface 20a of the sensor storage section 20A (see FIG. 4). Each vertical wall surface 21A of the slider 21 is provided with a stopper 21S that restricts the upward sliding movement of the slider 21. Each stopper 21S abuts against the bottom wall surface 20a of the sensor storage section 20A from below.

The bottom wall surface 21B of the slider 21 is a portion where the hook 14 ₁ H is engaged so as to be capable of being suspended, and below that, in the bottom portion, there is provided a reed switch 22 which is a second detector for detecting the presence or absence of the hook 14 ₁ H. The reed switch 22 is housed in a recess formed in the bottom portion of the slider 21.

The reed switch 22 is constructed by arranging two ferromagnetic reeds 22A and 22B facing each other with a predetermined contact distance and sealing them in a glass tube 22C. Each of the reeds 22A and 22B is housed in a recess 21h formed along the frame member of the slider 21. When the hook 14 ₁ H is not suspended from the bottom wall surface 21B of the slider 21, the reed switch 22 is in the OFF state. For convenience of illustration, each of the reeds 22A, 22B and the glass tube 22C is shown exposed on the front surface of the slider 21 in Figures 3 to 5, but each of the reeds 22A, 22B and the glass tube 22C is resin-sealed using, for example, epoxy resin.

Next, the internal structure of holder 2 will be described with reference to Figures 9 to 11. Note that a similar structure is also shown for holder 3, and only holder 2 will be described here.

9 to 11 show a state in which the cover 20B is removed from the holder 2 shown in FIGS.
As shown in Figures 9 to 11, the sensor accommodating section 20A of the holder 2 has a rear wall portion 20b which is approximately rectangular when viewed from the front and is located at the back of the paper in Figure 9, and side wall portions _20w1 , _20w2 , _20w3 , and _20w4 which are arranged in an approximately rectangular shape along the outer peripheral edge of the rear wall portion 20b and extend toward the front of the paper in the figure, and has a box-like shape with an opening on the front side of the paper in the figure.

The left and right side walls _20w3 , _20w4 are each formed with a notch 20n extending in the up-down direction (up-down direction in FIG. 9). Meanwhile, a pair of left and right shoulders 21k extending in the left-right direction is provided on the upper part of the frame-shaped member constituting the slider 21, and each shoulder 21k is inserted into each corresponding notch 20n. Each shoulder 21k has a vertical gap between itself and each corresponding notch 20n in the corresponding notch 20n. Each reed 22A, 22B of the reed switch 22 passes through each shoulder 21k, passes through the slider 21, and extends upward.

A pair of left and right return springs 24 arranged in the vertical direction are disposed near the left and right ends of the lower side wall portion _20w2 . The lower portion of each return spring 24 is held by a concave spring receiving portion 20s provided on the side wall portion _20w2 , and the upper end of each return spring 24 abuts against the lower surface of each shoulder portion 21k of the slider 21. At this time, each stopper 21S of the slider 21 abuts against the lower surface 20a of the side wall portion _20w2 . In addition, a support shaft portion _21k1 , _21k2 extending downward is provided on the lower surface of each shoulder portion 21k, and each support shaft portion _21k1 , _21k2 is inserted inside the upper portion of the corresponding return spring 24 to hold each return spring 24 from the inner circumferential side.

A sensor accommodating recess 21m is formed between the left and right shoulder portions 21k of the slider 21. A microswitch 23 is disposed in the sensor accommodating recess 21m as a first detector. In this example, the microswitch 23 has a hinge-lever type actuator 23s that rotates vertically. The tip of the actuator 23s is in pressure contact with the bottom portion 21f of the sensor accommodating recess 21m. At this time, that is, when the hook _14.sub.1H is not suspended from the bottom wall surface 21B of the slider 21, the microswitch 23 is in the ON state.

Next, Fig. 12 to Fig. 19 are external views of the state in which the hook 14 ₁ H is suspended from the slider 21, and Fig. 20 to Fig. 22 are views of the internal structure in that state. Fig. 20, Fig. 21, and Fig. 22 correspond to Fig. 16, Fig. 12, and Fig. 13, respectively. The holder (holder main body) 3 also shows a similar structure, and only the holder 2 will be described here. In Fig. 12 to Fig. 22, the tip portion of the hook 14 ₁ H is shown in a simplified manner, and the illustration of the stopper member and the like is omitted.

As shown in Fig. 12 to Fig. 19, the hook 14 ₁ H is hung and locked on the bottom wall surface 21B of the bottom of the slider 21, and at this time, the hook 14 ₁ H is located at a locking position with respect to the holder 2. A magnet (detection target) 14 ₁ m is fixed to the left and right side surfaces of the tip side of the hook 14 ₁ H by adhesive, adhesive tape, etc. The magnet 14 ₁ m may be fitted into a recess or protrusion formed on the side surface of the hook 14 ₁ H. Each magnet 14 ₁ m is disposed in the immediate vicinity of the bottom wall surface 21B with the hook 14 ₁ H locked on the bottom wall surface 21B. Also, at this time, each magnet 14 ₁ m is located above the contact of the reed switch 22, and as a result, the reed switch 22 detects one or both of the magnets 14 ₁ m, and the reed switch 22 is in an ON state. In this example, the hook 14 ₁ H to which the magnet 14 ₁ m is fixed and the holder 2 constitute a hook detection unit.

At this time, the hook 14 ₁ H is hung from the slider 21, and the weight of the hook 14 ₁ H and the strap 14 ₁ S of the lanyard 14 ₁ acts on the slider 21, causing the slider 21 to move downward (downward in FIG. 16). As a result, a gap e is formed between each stopper 21S of the slider 21 and the lower surface 20a of the sensor accommodating portion 20.

As shown in Figures 20 to 22, and particularly as can be seen by comparing Figure 20 with Figure 9, when the hook _141H is hung and locked on the bottom wall surface 21B of the bottom of the slider 21, the slider 21 moves downward (downward in Figure 20), causing the bottom 21f of the sensor accommodating recess 21m of the sensor accommodating portion 20A to move downward, and the bottom 21f moves away from the actuator 23s of the microswitch 23. This causes the microswitch 23 to be in the OFF state. At this time, each return spring 24 is compressed and deformed.

When the hook _14.sub.1H is removed from the slider 21 from this state, the slider 21 moves upward (upward in FIG. 20) due to the elastic repulsive force of each return spring 24, and each stopper 21S comes into contact with the lower surface 20a of the sensor housing portion 20 and stops (see FIG. 9). At this time, as described above, the bottom 21f of the sensor housing portion 20A comes into contact with the actuator 23s of the microswitch 23, turning the microswitch 23 ON. Meanwhile, the reed switch 22 is turned OFF because it can no longer detect the magnet _14.sub.1m of the hook _14.sub.1H .

In this way, the microswitch 23 as the first detector is means capable of detecting the load caused by the weight of the hook _14.1H or means capable of detecting the movement of the slider 21, and the reed switch 22 as the second detector is means capable of detecting that the hook _14.1H is located at the locking position relative to the slider 21 and therefore the holder 2. In other words, the microswitch 23 and the reed switch 22 are both means for detecting the presence or absence of the hook _14.1H in the holder 2. Also, as described above, the microswitch 23 and the reed switch 22 have different ON/OFF states both before and after the hook _14.1H is suspended, and have different output operation settings.

Next, the schematic block configuration of holder 2 will be described with reference to Fig. 23 and Fig. 23A. Fig. 23 shows an example of a schematic block configuration, and Fig. 23A shows another example of a schematic block configuration (the same applies to holder 3).

23, the holder 2 includes a communication unit CU capable of communicating with an external controller OC. The communication unit CU receives the outputs of the microswitch 23 and the reed switch 22, and is connected to a power source PS for supplying a power supply voltage to the microswitch 23 and the reed switch 22. The communication unit CU may be attached to any part of the body of the worker P (for example, the shoulder belts ₁₀₁ , ₁₀₂ or a helmet), or may be housed inside the holder 2 as a wireless module. The outputs of the microswitch 23 and the reed switch 22 may be input to the communication unit CU via a wired connection such as a cable or connector, or may be input wirelessly.

The external controller OC is installed, for example, at a location away from the work site, and each output information of the microswitch 23 and the reed switch 22 (i.e., the detection output of each switch 23, 22 as it is) is wirelessly transmitted via the communication unit CU. The external controller OC has an abnormality detection unit (not shown) that detects an abnormality by determining whether the outputs of the switches 23, 22 are normal and different from each other or abnormal and both outputs are the same based on the detection results of the switches 22, 23 obtained from the received output information of the microswitch 23 and the reed switch 22, and an alarm unit (not shown) that issues an alarm or issues a warning message when an abnormality is detected by the abnormality detection unit. By installing the external controller OC at a location away from the work site, the work status of the worker P can be monitored at a location away from the work site.

In the example shown in FIG. 23A, the holder 2 has a controller (or microcomputer) C. The detection outputs of the microswitch 23 and the reed switch 22 are input to the controller C, and a power supply PS is connected to supply a power supply voltage to the microswitch 23 and the reed switch 22. The controller C has an abnormality detection section (not shown) that detects an abnormality by determining whether the outputs of the switches 23, 22 are normal and different from each other, or abnormal and both outputs are the same, based on the detection results of the microswitch 23 and the reed switch 22. In addition, the controller C is connected to a communication unit CU that can communicate the determination result by the controller C to an external controller OC, and an alarm section AP that issues an alarm or broadcasts a warning message when an abnormality is detected by the abnormality detection section.

The controller C, communication unit CU and alarm section AP may be attached to any part of the body of the worker P (for example, the shoulder belts ₁₀₁ , ₁₀₂ , a helmet, etc.), or may be integrated and housed inside the holder 2. The external controller OC is installed, for example, at a location away from the work site, and information on whether the microswitch 23 and the reed switch 22 are in a normal state or an abnormal state is wirelessly received via the communication unit CU, making it possible to monitor the work status of the worker P at a location away from the work site.

Next, the effects of this embodiment will be described.
Although only the holder 2 will be described here, the holder 3 also provides the same effects.
As described above, when the hook _14.sub.1H of the fall arrest device 1 is hung and engaged on the slider 21 of the holder 2 (see FIGS. 16 and 20), the state in which the hook is present on the holder 2 is detected by the microswitch 23 and the reed switch 22. At this time, as shown in the "hook present" column in FIG. 24, the output states of the switches 23, 22 are "OFF" (first detection output) for the microswitch 23 and "ON" (second detection output), and the output operation settings of the switches 23, 22 are different.

In this way, when the hook-present state is detected by the microswitch 23 and the reed switch 22, the outputs of the switches 23, 22 are different from each other, and only when the microswitch 23 is "OFF" and the reed switch 22 is "ON" does the switch 23, 22 detect the hook-present state. This makes it possible to reliably detect the hook-present state in the holder 2. Moreover, in this case, a general-purpose hook can be used without the need for a special dedicated hook (in this example, the magnet _14.1m is simply attached later), making it possible to construct at low cost.

In addition, even if the hook _14.sub.1H vibrates up and down on the slider 21 due to vigorous body movement of the worker P when the hook is in the hooked state and moves slightly upward from the locking position on the slider 21, the reed switch 22 has a certain detection range and can maintain the ON state without turning OFF, thereby preventing the reed switch 22 from malfunctioning due to the body movement of the worker P.

On the other hand, as described above, when the hook _14.sub.1H of the fall arrest device 1 is removed from the slider 21 of the holder 2 (see FIGS. 5 and 9), the state in which there is no hook on the holder 2 is detected by the microswitch 23 and the reed switch 22. At this time, as shown in the "no hook" column in FIG. 24, the output states of the switches 23, 22 are "ON"(first' detection output (≠ first detection output)) for the microswitch 23 and "OFF"(second' detection output (≠ second detection output and first' detection output)), and the output operation settings of the switches 23, 22 are different.

In this way, when the no-hook state is detected by the microswitch 23 and the reed switch 22, the outputs of the switches 23, 22 are different from each other, and only when the microswitch 23 is "ON" and the reed switch 22 is "OFF", each switch 23, 22 detects the no-hook state. This makes it possible to reliably detect the no-hook state on the holder 2. Moreover, in this case, a general-purpose hook can be used without the need for a special dedicated hook (in this example, the magnet _14.1m is simply attached later), making it possible to configure at low cost.

In this manner, the presence or absence of the hook 14 ₁ H in the holder 2 can be detected reliably with an inexpensive configuration, and the presence or absence of the hook 14 ₁ H in the holder 2 can be monitored.

As shown in the right column of Figure 24, if the output states of the microswitch 23 and reed switch 22 are both "OFF" or "ON" and the output operation of each switch 23, 22 is the same, it can be detected that an abnormality has occurred due to contact welding, short circuit, disconnection, switch failure, etc.

Here, FIG. 25 shows another example of the output operation settings of the microswitch 23 and reed switch 22 of the holder 2. As shown in the figure, the output operation settings of the microswitch 23 and reed switch 22 in normal times are the opposite of the example shown in FIG. 24. That is, when there is a hook, the microswitch 23 is "ON" and the reed switch 22 is "OFF" (in FIG. 24, the microswitch 23 is "OFF" and the reed switch 22 is "ON"), and when there is no hook, the microswitch 23 is "OFF" and the reed switch 22 is "ON" (in FIG. 24, the microswitch 23 is "ON" and the reed switch 22 is "OFF"). In this case, too, the microswitch 23 and the reed switch 22 can be said to have different output operation settings. The output operation settings in abnormal times are the same as in FIG. 24.

To set the output operation as shown in Fig. 25, for example, it is possible to place the microswitch 23 in the internal space S defined by the bottom 21f of the sensor accommodating recess 21m and the lower side wall 20w2 of the sensor accommodating portion 20A of the holder ₂ in Fig. 9. In this case, the space occupied by the microswitch 23 is secured even after the hook is suspended by widening the vertical distance of the internal space S. Also, it is possible to adopt an NC type reed switch (i.e., the contacts are opened and the switch is turned OFF only when the magnets _141m , _142m of the hook _141H approach each other) instead of the NO type reed switch 22 shown in Figs. 9 and 20 (i.e., the contacts are closed and the switch is turned ON only when the magnets _141m , _142m of the hook _141H approach each other).

Regarding the presence or absence of the hook 14 ₁ H in the holder 2, the microswitch 23 detects the load caused by the weight of the hook 14 ₁ H or detects the movement of the slider 21, and the reed switch 22 detects that the hook 14 ₁ H is in an engaging position with respect to the slider 21. Since each detects a different detection target, it becomes possible to more reliably detect the presence or absence of the hook 14 ₁ H of the fall arrest device 1.

Furthermore, when worker P hangs hook _141H on slider 21, even if hook _141H is hung from inclined surface 21C rather than from bottom wall surface 21B at the bottom of slider 21 from the beginning (see dashed line in Figure 20), since inclined surface 21C is inclined downward, hook _141H on inclined surface 21C moves downward along inclined surface 21C by its own weight and moves onto bottom wall surface 21B, so that hook _141H can be easily positioned at the engaging position on bottom wall surface 21B.

In this embodiment, a double lanyard type fall arrest device 1 having two lanyards _{141, 142 is used as an example (see Figures 1 and 2). In such a double lanyard type device, the hooks 141H , 142H of the} two lanyards 141, ₁₄₂ are alternately hooked to structures at the work site, eliminating the state in which both lanyards are not attached to a structure (no belly rope state) and ensuring that one of the lanyards is always connected to the structure, thereby avoiding the risk of a fall.

Therefore, in a double lanyard type fall arrest device 1 such as this embodiment, when detecting an abnormality in holders 2, 3 using external controller OC (Fig. 23) or controller C (Fig. 23A), as described above, it is possible to ensure higher safety by not only detecting an abnormality in each of holders 2 or 3 (i.e., holder 2 alone or holder 3 alone) but also detecting whether holder 3 (or holder 2) is in a hooked state when holder 2 (or holder 3) is in an unhooked state, i.e., whether both holders 2 and 3 are in a hooked state. Also, by detecting the presence or absence of hooks in both holders 2, 3, it is possible to monitor whether worker P is working safely.

[First Modification]
In the above embodiment, the slider 21 is configured from a frame-shaped member having a hook suspension part of a roughly pentagonal shape (see Figs. 5, 16, and 20), but the application of the present invention is not limited to this. As shown in Fig. 26, the slider 21 may be configured from a frame-shaped member having a hook suspension part of an arc shape (e.g. semicircular/elliptical/oval/elliptical, etc.). This figure corresponds to the hook suspension part in Fig. 20 of the above embodiment (however, the stopper 21S is omitted (the same applies to each of the following modified examples)).

In this case, since the hook hanging portion of the slider 21 has a downwardly convex arcuate surface 21D, when the worker P hangs the hook 14 ₁ H from the slider 21, even if the hook 14 ₁ H is not hung from the bottom of the arcuate surface of the slider 21 but is hung from the inclined portion of the arcuate surface 21D (see the dashed line in FIG. 26), the hook 14 ₁ H on the inclined portion of the arcuate surface 21D moves downward along the arcuate surface 21D by its own weight to the bottom, so that the hook 14 ₁ H can be easily positioned at the engaging position on the bottom.

[Second Modification]
In the above embodiment, the slider 21 is configured from a frame member having a hook suspension part having a substantially pentagonal shape (see Figs. 5, 16, and 20), but the application of the present invention is not limited to this. As shown in Fig. 27, the slider 21 may be configured from a frame member having a rectangular hook suspension part (U-shaped in the illustrated example). This figure corresponds to the hook suspension part in Fig. 20 of the above embodiment.

As shown in FIG. 27, the slider 21 has a pair of left and right vertical wall surfaces 21A and a bottom wall surface 21B disposed at the bottom. Reed switches 22, 22' are provided inside the bottom near the left and right ends, respectively. The reed switch 22 has a glass tube 22C with contacts disposed therein, and similarly, the reed switch 22' has a glass tube 22'C with contacts disposed therein.

In this case, reed switches 22, 22' are provided at two positions near the left and right ends of the bottom having a flat bottom wall surface 21B, so that hook _14.1H can be reliably detected by either of reed switches 22, 22' regardless of where hook _14.1H is placed on bottom wall surface 21B.

[Third Modification]
In the above embodiment, the reed switch 22 is used as the second detector, but the application of the present invention is not limited to this. Fig. 28 shows a third modified example of the present invention, in which a tape switch 25 is provided in an arc shape along the bottom wall surface 21B at the bottom of the slider 21 made of a frame member having an arc-shaped hook hanging portion as shown in Fig. 26.

The tape switch 25 is generally a thin tape-like switch with multiple switches arranged along its length, and is configured to function as a switch no matter where in the length direction it is pressed. In this case, when the hook 14 ₁ H is hung from the bottom of the slider 21, the weight of the hook 14 ₁ H and the strap 14 ₁ S of the lanyard 14 ₁ acts on the tape switch 25, turning the tape switch 25 ON.

In the above embodiment, it was necessary to attach magnets _141m to the left and right sides of hook _141H as the detection object of reed switch 22. However, in this third modified example, since tape switch 25 detects the load due to hook _141H and strap _141S of lanyard ₁₄₁ , there is no need to attach a component such as magnet _141m later, and general-purpose hook _141H can be used as is.

Also, in this case, since the hook hanging portion of slider 21 has downwardly convex arcuate surface 21D, even if worker P is unable to hang hook 14 ₁ H from the bottom of arcuate surface 21D of slider 21 and hangs it from the inclined portion of arcuate surface 21D (see dashed line in FIG. 28), hook 14 ₁ H on arcuate surface 21D moves downward along arcuate surface 21D by its own weight to the bottom, so that hook 14 ₁ H can be easily positioned at the engaging position on the bottom.

[Fourth Modification]
FIG. 29 shows a fourth modified example of the present invention, in which a tape switch 25 is provided in a straight line along the bottom wall surface 21B at the bottom of the slider 21 consisting of a frame-shaped member having a U-shaped hook hanging portion as shown in FIG. 27.

Even in this case, when the hook 14 ₁ H is suspended from the bottom of the slider 21, the load due to the weight of the hook 14 ₁ H and the strap 14 ₁ S of the lanyard 14 ₁ acts on the tape switch 25, turning the tape switch 25 ON.

In this case, the tape switch 25 is provided along the flat bottom wall surface 21B, so that no matter where the hook 14 ₁ H is placed on the bottom wall surface 21B, the hook 14 ₁ H can be reliably detected by a switch placed at any part of the tape switch 25.

In the above embodiment, it was necessary to attach magnets _141m to the left and right sides of hook _141H as the detection object of reed switch 22. However, in this fourth modified example, since tape switch 25 detects the load due to hook _141H and strap _141S of lanyard ₁₄₁ , there is no need to attach a component such as magnet _141m later, and general-purpose hook _141H can be used as is.

[Fifth Modification]
30 shows a fifth modified example of the present invention. In this fifth modified example, a transmission type photoelectric switch 26 is provided on a vertical wall of a slider 21 made of a frame-shaped member having a generally pentagonal hook hanging portion. The transmission type photoelectric switch 26 has a light-emitting portion 26A disposed on one vertical wall, and a light-receiving portion 26B disposed on the other vertical wall at a position opposite to the light-emitting portion 26A.

In this case, when the hook _141H is hung from the bottom of the slider 21, the hook-present state is detected because the light L emitted from the light-projecting unit 26A is blocked by the hook _141H and is not received by the light-receiving unit 26B. On the other hand, when the hook _141H is removed from the bottom of the slider 21, the light L emitted from the light-projecting unit 26A is received by the light-receiving unit 26B, and the hook-absent state is detected.

In the above embodiment, it was necessary to attach magnets _14.1m to the left and right side surfaces of the hook _14.1H as the detection object of the reed switch 22. However, in this fifth modified example, since the hook _14.1H itself is the detection object, there is no need to attach a component such as the magnet _14.1m later, and the general-purpose hook _14.1H can be used as is.

[Sixth Modification]
31 shows a sixth modified example of the present invention. In this sixth modified example, a polarized regression reflection type photoelectric switch 27 is provided on the vertical wall of a slider 21 made of a frame member having a hook hanging part of a roughly pentagonal shape, and a reflector 28 is provided on the side surface of the hook 14 ₁ H as a part to be detected.

In this case, when the hook _141H is hung from the bottom of the slider 21, the light _L1 emitted from the photoelectric switch 27 is reflected by the reflector 28 and the reflected light _L2 is received by the photoelectric switch 27, thereby detecting a hook-present state. On the other hand, when the hook _141H is removed from the bottom of the slider 21, the light _L1 emitted from the photoelectric switch 27 is not reflected by the reflector 28 and the reflected light _L2 is not received by the photoelectric switch 27, thereby detecting a hook-absent state.

In the above embodiment, the first and second modified examples, and the sixth modified example, it is necessary to retrofit the magnet _14.1m and the reflector 28 to the side surface of the hook _14.1H . By retrofitting such components and making them the detection target of the second detection unit, it is possible to prevent the second detection unit from malfunctioning by detecting something other than the detection target, and to avoid disabling the second detection unit.

For example, in the third and fourth modified examples, an example was shown in which a tape switch 25 was provided as the second detection unit (see Figs. 28 and 29), but since the tape switch 25 detects a downward load, even if something other than the hook 14 ₁ H (e.g., a mechanical part, etc.) is hung from the bottom of the slider 21, there is a risk that the tape switch 25 will be turned ON, causing a malfunction or inhibiting the original function of the tape switch 25 and thus rendering it ineffective. Also, in the fifth modified example, an example was shown in which a transmissive photoelectric switch 26 was provided as the second detection unit (see Fig. 30), but even in this case, there is a risk that when something other than the hook 14 ₁ H (e.g., a mechanical part, etc.) is hung from the bottom of the slider 21, the transmissive photoelectric switch 26 will detect the mechanical part, etc., causing a malfunction or inhibiting the original function of the transmissive photoelectric switch 26 and rendering it ineffective.

In contrast, in the embodiment, the first and second modified examples, and the sixth modified example, only the hook 14 ₁ H having the magnet 14 ₁ m or the reflector 28 attached to the side surface is detected, so that the above-mentioned malfunction or invalidation can be prevented.

[Seventh Modification]
Figures 32 and 33 show a seventh modified example of the present invention. Figure 32 corresponds to Figure 9 of the above embodiment, and the same reference numerals as those in Figure 9 indicate the same or corresponding parts. This seventh modified example differs from the above embodiment in that a three-position enable switch 29 is provided instead of the microswitch 23 serving as the first detector in Figure 9. Also, the reed switch 22 serving as the second detector provided at the bottom of the slider 21 has an output operation setting as shown in Figure 25.

As shown in Fig. 32, a three-position enable switch (hereinafter, simply referred to as "enable switch") 29 is disposed as a first detection unit in the sensor accommodating recess 21m of the slider 21. The push button 29a of the enable switch 29 is disposed on the upper side of the enable switch 29 as shown in the figure. Meanwhile, an operation bar 21g extending in the left-right direction is hung between the left and right shoulder parts 21k of the slider 21, and the left and right ends of the operation bar 21g are connected to the corresponding shoulder parts 21k. Moreover, as shown in Fig. 32, when the hook 14 ₁ H is not suspended from the slider 21, the operation bar 21g is preferably in contact with the upper end of the push button 29a of the enable switch 29 with no gap, and at this time, no load is applied to the push button 29a in the downward direction as shown.

Next, the operation of the enable switch 29 will be explained using FIG. 33. As shown in (a) to (c) of the same figure, the enable switch 29 is configured to be able to take three positions, position 1 to position 3, with position 1 corresponding to the state in FIG. 32.

In addition, in this seventh modified example, in order to allow the slider 21 to move further downward from the state in position 2 in FIG. 33(b) (i.e., the state shown in FIG. 20 of the previous embodiment), the vertical gap between each shoulder 21k of the slider 21 and each corresponding notch 20n is made larger than in the previous embodiment (not shown in FIG. 32).

33(a), in the state of position 1, the hook 14 ₁ H is not suspended from the slider 21, and at this time, no downward load is applied to the push button 29 a from the operation bar 21 g of the slider 21, the movable contact 29 b is located at a position separated from the fixed contact 29 c, and the contact is in the "OFF" state. Also, at this time, the contact of the reed switch 22 is in the "ON" state (see FIG. 25).

Next, when the hook _14.sub.1H is hung from the slider 21 (see FIGS. 16 and 20 of the above embodiment), the enable switch 29 transitions from position 1 to position 2 as shown in FIG. 33(b). At this time, the slider 21 moves downward due to the weight of the hook _14.sub.1H and the strap _14.sub.1S of the lanyard _14.sub.1 , and the operation bar 21g of the slider 21 moves downward accordingly. As a result, the push button 29a is pushed in by the operation bar 21g, and the movable contact 29b comes into contact with the fixed contact 29c, turning the contact "ON". At this time, the contact of the reed switch 22 turns "OFF" (see FIG. 25).

From this state, when the worker P removes the hook _141H from the slider 21, the slider 21 moves upward due to the elastic repulsive force of the return spring 24, and the operation bar 21g of the slider 21 moves upward accordingly. As a result, the push button 29a also moves upward, and the enable switch 29 returns from position 2 to position 1 (see FIG. 33(a)).

On the other hand, in the state of position 2 in Figure 33 (b), let us assume that the worker P mistakenly hangs another hook 14 ₂ H (see Figures 1 and 2) from the same slider 21. At this time, the slider 21 is in a state where two hooks 14 ₁ H and 14 ₂ H are hanging, and is in an overload (i.e., excessively large) state.

Then, as shown in Figure 33(c), the enable switch 29 transitions from position 2 to position 3. At this time, the slider 21 moves further downward due to the load caused by the weight of the hooks _141H , _142H and the straps _141S , _142S , and the operation bar 21g of the slider 21 moves further downward accordingly. This causes the push button 29a to be pressed further by the operation bar 21g, and as a result, the movable contact 29b moves to a position separated from the fixed contact 29c, and the contact becomes "OFF". At this time, the contact of the reed switch 22 maintains the "OFF" state (see Figure 25).

In this case, both the enable switch 29 and the reed switch 22 are in the "OFF" state, and an abnormal condition has occurred as shown in the right column of Figure 25. Therefore, the alarm unit will issue a warning message such as, "An abnormal condition has been detected. Please check the work procedures and safety."

From this state, when the worker P removes one of the hooks (e.g., hook 14 ₂ H) from the slider 21 (at this time, the other hook (e.g., hook 14 ₁ H) remains hooked on the slider 21), the enabling switch 29 maintains the "OFF" state, and the reed switch 22 similarly maintains the "OFF" state. Even in this case, both the enabling switch 29 and the reed switch 22 are in the "OFF" state, and the abnormal state continues, so the alarm unit continues to issue a warning message, such as "An abnormal state has been detected. Please check the work procedures and safety."

Next, when the worker P removes the remaining hooks from the slider 21 so that no hooks are hanging from the slider 21, the enable switch 29 returns from position 3 to position 1 (see FIG. 33(a)). At this time, the contact of the enable switch 29 is in the "OFF" state, and the contact of the reed switch 22 is in the "ON" state, and both switches return to the no-hook state. This stops the warning message from the alarm unit. The worker P then hangs the corresponding hooks 14 ₁ H and 14 ₂ H from the holders 2 and 3 one by one.

According to such a seventh modified example, when two hooks ₁₄ 1H, 14 _2H are hung from the slider 21 of the holder 2 (similarly for the holder 3), if an overload acts on the slider 21, the contact of the enable switch 29 as the first detection unit automatically turns "OFF", so that it becomes possible to easily detect that an overload has acted on the slider 21 (and therefore the holder 2). Also, in this case, unless both hooks ₁₄ 1H, 14 _2H are temporarily removed from the slider 21, the abnormal state cannot be overcome and the warning message cannot be stopped, so that the operator P can be encouraged not to hang two hooks from one holder.

The above-mentioned enable switch 29 is configured to return directly from position 3 to position 1 without passing through position 2 when returning from position 3 to position 1 (i.e., position 3 ⇒ position 1), but the present invention can also be applied to a three-position switch configured to return from position 3 to position 2 and then to position 1 (i.e., position 3 ⇒ position 2 ⇒ position 1). In this case, when one of the hooks is removed from the state in which two hooks are suspended from the slider 21, the three-position switch transitions from position 3 to position 2, turning the contacts "ON", thereby eliminating the abnormal state that occurs when two hooks are suspended from the slider 21.

In the seventh modified example, a specific example of an overload acting on the slider 21 has been described with reference to a case where two hooks 14 ₁ H and 14 ₂ H are suspended from the slider 21, but the application of the present invention is not limited to this. Another specific example of an overload acting on the slider 21 is when the worker P, with one hook 14 ₁ H suspended from the slider 21, gets the strap 14 ₁ S caught on something while working or walking, trips and falls, or falls. Even in such a case, it is possible to detect the abnormal state.

[Eighth Modification]
Fig. 34 shows an eighth modification of the present invention. As shown in the figure, in this eighth modification, in addition to the microswitch 23 as the first detection unit and the reed switch 22 as the second detection unit, third detection units 25A and 25B are provided. The third detection units 25A and 25B are provided in an internal space S defined by the bottom 21f of the sensor accommodating recess 21m of the slider 21 and the lower side wall 20w2 of the sensor accommodating unit 20A of the holder _2. As the third detection units 25A and 25B, for example, an inductive proximity sensor or a capacitive proximity sensor can be considered.

In this case, by providing a third detector in addition to the first and second detectors, it becomes possible to more reliably detect the presence or absence of a hook on the holder.

[Ninth Modification]
In the above embodiment and each of the modified examples, the first and second detectors are set to different output operation settings, but the application of the present invention is not limited to this. The present invention can also be applied to a case where the first and second detectors are set to the same output operation settings.

For example, in FIG. 24, the output operation setting of the reed switch may be left as is, and the output operation setting of the microswitch may be set to "ON" when the hook is present and "OFF" when the hook is not present. Conversely, the output operation setting of the microswitch may be left as is, and the output operation setting of the reed switch may be set to "OFF" when the hook is present and "ON" when the hook is not present. In these cases, in an abnormal state, either the microswitch or the reed switch will be "ON" and the other will be "OFF".

In this way, to set the same output operation for the reed switch and the microswitch, the microswitch in FIG. 24 can be combined with the reed switch in FIG. 25, or the reed switch in FIG. 24 can be combined with the microswitch in FIG. 25. Alternatively, in the first and second detection units having different output operation settings, the output of one of the detection units can be inverted outside (or inside) the holder 2. Furthermore, the controller can determine that the output of one of the detection units is the inverted output.

[Tenth Modification]
In the above embodiment and each of the modified examples, various sensors have been described as examples of the first and second detection units, but the first and second detection units in the present invention are not limited to those exemplified, and various other sensors may be adopted. For example, a pressure sensor or a strain gauge may be used. It is also possible to use an RFID (Radio Frequency Identification) tag and reader. In this case, for example, an RFID tag may be attached to the hook side, and a reader that reads the information stored in the RFID tag may be attached to the holder side.

[Other Modifications]
The above-described embodiment and each modification should be considered in all respects as merely illustrative of the present invention, and not restrictive. Those skilled in the art to which the present invention pertains may, when considering the teachings above, construct various modifications and other embodiments that incorporate the principles of the present invention without departing from the spirit and essential characteristics of the present invention, even if not expressly described herein.

[Other application examples]
In the above embodiment, the holder according to the present invention is applied to a full harness type fall arrest device, but the present invention can also be applied to a waist belt type fall arrest device. Also, in the above embodiment, the holder according to the present invention is applied to a double lanyard type fall arrest device having two lanyards, but the present invention can also be applied to a single lanyard type fall arrest device having one lanyard.

The present invention is useful for a holder capable of hanging a hook attached to a fall prevention device, a hook detection unit including the holder, and a hook detection method.

1: Fall prevention equipment

2, 3: Holder (holder body)
20: Base 21: Slider 22: Reed switch (second detection unit)
23: Microswitch (first detection unit)
25A, 25B: Third detector 29: Three-position enable switch (first detector)

14 ₁ H, 14 ₂ H: Hook 14 ₁ m: Magnet (detection target)

CU: Communication unit AP: Alarm section

Japanese Patent No. 5822796 (see paragraph [0026] and FIG. 5)

Claims (9)

A holder capable of hanging a hook provided on a fall prevention device,
a holder body that engages the hook so as to be capable of being hung;
a first detector and a second detector configured to detect the presence or absence of the hook in the holder body;
an abnormality detection unit that detects an abnormality based on detection results of the first and second detection units;
A holder comprising: In claim 1,
The first detection unit is a means capable of detecting a load caused by the weight of the hook, and the second detection unit is a means capable of detecting that the hook is positioned at a locking position relative to the holder body.
A holder characterized by: In claim 1,
the holder body includes a base that is attached to a side of a body of an operator, and a slider that is slidably provided on the base and to which the hook can be engaged;
the first detection unit is a means capable of detecting a movement of the slider when the hook is engaged with the slider, and the second detection unit is a means capable of detecting that the hook is positioned at a locking position relative to the slider.
A holder characterized by: In claim 1 ,
The device further includes an alarm unit that issues an alarm when an abnormality is detected by the abnormality detection unit.
A holder characterized by: In claim 1,
The first or second detection unit is a means capable of detecting that an excessive load has been applied to the holder main body.
A holder characterized by: In claim 1,
The first or second detection unit is a means capable of detecting a detection target provided on the hook.
A holder characterized by: A hook detection system for a fall prevention device having a hook and a holder capable of suspending the hook,
a first detector and a second detector for detecting the presence or absence of the hook in the holder;
a controller that determines whether the state is normal or abnormal based on detection results of the first and second detection units;
A hook detection system with In claim 7,
the holder and the hook each include a pair of left and right members, the first and second detection units are provided on each of the holders,
the controller detects whether the holder is in a normal state or an abnormal state based on the detection results of the first and second detection units of each of the holders;
1. A hook detection system comprising: A hook detection method for detecting the presence or absence of a hook in a holder capable of suspending the hook of a fall prevention device, comprising:
The holder has first and second detection units for detecting the presence or absence of the hook,
The hook detection method comprises:
a hook presence detection step in which the first detection unit outputs a first detection output and the second detection unit outputs a second detection output when the hook is hung on the holder;
a hook absence detection step in which, when the hook is removed from the holder, the first detection unit outputs a first' detection output having an output operation setting different from that of the first detection output, and the second detection unit outputs a second' detection output having an output operation setting different from that of the second detection output;
an abnormality detection step of detecting an abnormality when the first detection unit outputs a first detection output and the second detection unit outputs the second' detection output, or when the first detection unit outputs a first' detection output and the second detection unit outputs the second detection output;
A hook detection method comprising:

Images