JP7114069B2 - Shock absorber for safety belt and fall arrest device using the same - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shock absorber for a safety belt worn by a worker to prevent a fall during work at height, and a fall prevention device using the same.

Safety belts worn by workers working at heights such as construction sites are designed to protect the workers from the impact of the lanyard straps and ropes in the event of an accidental fall. It is common to provide a shock absorber for mitigating the

As such a shock absorber, for example, as described in Patent Documents 1 and 2 below, upper and lower belts woven with synthetic fibers such as nylon and polyester are superimposed and the overlapped portion is woven with leno yarn. In general, the belt is covered with a tube in a folded state, and when an operator falls and impacts the belt, the leno yarn interwoven with the overlapped portion is cut one after another to absorb the impact.

JP-A-58-220845 Registered Utility Model No. 3082515

However, the above-mentioned shock absorber stretches easily when the temperature and humidity are high, and the belt and thread deteriorate when used outdoors for a long period of time. It may not be mitigated as expected.

In addition, when combined with a winder that prevents the strap from being let out in an emergency, it may be bulky and bothersome for workers.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a shock absorber having stable load characteristics that is not affected by the operating environment in an emergency, and to provide a compact fall arrest device using the shock absorber.

In order to solve the above-mentioned problems, the present invention provides a safety belt shock absorber that is provided in a safety belt worn by a worker who works at height and that mitigates the impact acting on the worker in an emergency through the belt.
The belt is wound around the outer periphery of a spool sandwiched between opposing bases and held rotatably, and one locking end of a torsion bar is locked to one end of the spool so as to rotate together, the other locking end of the torsion bar is locked to one of the bases so as not to rotate;
In the event of an emergency, the pulling force of the belt from the spool twists the shaft portion of the torsion bar and reduces the impact acting on the worker.

In the shock absorber, the end of the belt passes through a radial hole formed in the spool without being fixed inside the spool, and is double-wound around the outer periphery of the spool,
In an emergency, the belt is simultaneously pulled out in both directions from the spool as the spool rotates.

A winder is integrally provided with the shock absorber, and the winder is urged in the winding direction so that the wound strap can be pulled out at any time, and in an emergency, the strap is prevented from being let out by a lock mechanism. In a fall arrest device for a safety belt that
The spool for winding the strap of the winder is rotatably held by being sandwiched between opposing bases shared with the shock absorber,
A strap pin to which the end of the strap is attached is held inside the spool, but does not serve as a rotation support shaft of the spool.
The strap is wound around the outer circumference of the spool from the strap pin via the inside of the spool.

Further, the winder and the spool of the shock absorber are held in the thrust direction by being fastened while maintaining the space between the opposing bases.

In the safety belt shock absorber according to the present invention, the shock is absorbed by twisting the shaft of the torsion bar made of metal such as steel, instead of breaking the leno thread that interweaves the overlapped portion of the belt. Since the load is relaxed, stable load characteristics can be obtained according to the set value without being affected by the usage environment.

The spool can also be integrated in combination with a winder rotatably held by opposing bases to form a compact fall arrest device that is not bulky.

1 is an exploded perspective view of a reference form of a shock absorber for a safety belt according to the present invention; FIG. A perspective view showing an assembled state in which the case on one side of the same is opened. Cross-sectional plan view of the intermediate part in the thickness direction of the same Vertical cross-sectional side view of the same case closed FIG. 11 is a cross-sectional plan view showing a state after the torsion bar is twisted; FIG. 11 is a cross-sectional plan view of another form of the spool in the middle part in the thickness direction. FIG. 11 is a cross-sectional plan view showing a state after the torsion bar is twisted; 1 is a perspective view showing an assembled state in which one side case of an embodiment of a safety belt shock absorber according to the present invention is opened; FIG. Cross-sectional plan view of the intermediate part in the thickness direction of the same 1 is a perspective view showing an assembled state with one case opened in a first embodiment of a safety belt fall arrest device integrating a shock absorber and a winder according to a reference embodiment of the present invention; FIG. Cross-sectional plan view of the intermediate part in the thickness direction of the same Vertical cross-sectional side view of the same case closed The perspective view which shows the assembly state which opened the case of one side in 2nd Embodiment of the fall arrest apparatus for safety belts same as the above.

First, a reference form of the shock absorber will be described with reference to FIGS. 1 to 7. FIG.

As shown in FIGS. 1 to 4, this shock absorber has components housed inside a pair of cases 41, and has a shape having hexagonal locking ends 30b at both ends of a columnar shaft 30a. The main components are a torsion bar 30 made of steel, a spool 31 around which the belt 3 is wound, and two plate-like bases 12 sandwiching the spool 31 .

The spool 31 is an integrally molded product by die casting of an aluminum alloy, a zinc alloy, or the like, and has flanges 31b on both end sides of a winding drum portion 31a around which the belt 3 is wound. It has a shape in which the portion 31c protrudes. The outer periphery of the fitting portion 31c has a cylindrical shape with a diameter smaller than that of the flange 31b.

The winding drum portion 31a is formed with an axial core hole 31d into which the torsion bar 30 is inserted with a gap. Inside one end (lower end in FIGS. 1 and 4) of the core hole 31d, the end wall of the spool 31 bulges outward to form a locking recess 31e recessed in a hexagonal shape, and the other end (lower end in FIGS. 1 and 4). 1 and the upper end in FIG. 4) are open.

One locking end 30b of the torsion bar 30 (lower in FIGS. 1 and 4) is fitted into a locking recess 31e, and the center of one end of the spool 31 (center of the lower end in FIGS. 1 and 4) part) so as to rotate together.

Further, the winding drum portion 31a is formed with a middle through hole 31f extending from one side of the outer periphery to the other side of the outer periphery through the core hole 31d. The width of the entrance portion at one end of the through hole 31f is set slightly larger than the diameter of the belt pin 32 to which the end of the belt 3 is folded and fixed, and the width of the side communicating with the core hole 31d is set to be the diameter of the belt pin 32. is set smaller than

Then, the belt 3 is inserted into the spool 31 from the entrance portion of one end of the through hole 31f, and is prevented from coming out of the spool 31 with the folded end fixed to the belt pin 32, and the core hole 31d. , and then pulled out from the other end of the middle through hole 31f, and then wound around the outer circumference of the winding drum portion 31a.

The base 12 is made of steel harder than the spool 31 and has round fitting holes 12c. The spool 31 is rotatably held by being fitted into the mating hole 12c.

The base 12 on one side (the upper side in FIGS. 1 and 4) has a receiving plate portion 12d protruding from one end side so as to cover the fitting hole 12c. is formed, and an end plate member 34 is attached with a screw 35 so as to cover the locking hole 12e.

The other (upper in FIGS. 1 and 4) engaging end portion 30b of the torsion bar 30 is fitted into the engaging hole 12e of the receiving plate portion 12d, and the one (upper in FIGS. 1 and 4) is fitted into the engaging hole 12e. Locked to the base 12 so as not to rotate, the torsion bar 30 is held by an end plate member 34 so as not to slip out of the lock hole 12e in the axial direction.

As shown in FIGS. 1 to 4, on one side between the two bases 12 where the belt 3 is pulled out, two guide rollers 36a for guiding the belt 3 from both sides are connected to a rotating shaft 36b. is rotatably held by

The four corners of the two bases 12 are fastened by bolts 20a that are inserted through holes in one base 12 and screwed into screw holes in the other base. , the distance between the two bases 12 is maintained. Thereby, the spool 31 is sandwiched between the two bases 12 and held in the thrust direction.

Attached to the other side of the two bases 12 is a connection pin 37 for locking the lanyard belt 4, rope, metal fittings, and the like. Both ends of the connection pin 37 are inserted into holes near the other edges of the two bases 12 .

A base receiving portion 41b surrounded by a circular peripheral wall is provided on the inner bottom surface of the case 41 on one side (the lower side in FIGS. 1 and 4) and bulges outward corresponding to the locking recess 31e of the spool 31. is fitted inside the base receiving portion 41b and abuts on the inner bottom surface of the base receiving portion 41b.

Then, one case 41 is covered with the other case 41 (upper in FIGS. 1 and 4) so as to house the components assembled in this way, and the cases 41 are attached to each other at their four corners. The screws 23 inserted through the holes of the case 41 are screwed into the threaded holes of the other case 41, and the shock absorber is assembled.

When a worker wears a safety belt equipped with a shock absorber as described above and accidentally falls during work at a height, the spool 31 is pulled by the belt 3 and tries to rotate. The locking end portion 30b also tries to rotate, but the other locking end portion 30b of the torsion bar 30 is locked to one of the bases 12 so as not to rotate. As a result, the belt 3 is pulled out with a constant load, and the impact is alleviated.

Then, as shown in FIG. 5, when the belt 3 is fully pulled out, the cushioning is finished. By adjusting the amount of winding of the belt 3 around the spool 31 and appropriately setting the pull-out stroke of the belt 3, it is possible to obtain a predetermined cushioning performance.

In the safety belt shock absorber as described above, the torsion of the shaft portion 30a of the torsion bar 30 mitigates the impact, so it is not affected by the operating environment such as temperature, humidity, and aging deterioration due to long-term outdoor use. , stable load characteristics can be obtained according to the set value, and the size can be reduced while ensuring sufficient cushioning performance.

As shown in FIGS. 6 and 7, the spool 31 is formed with two through holes 31f extending in the string direction from one side of the outer periphery to the other side across the core hole 31d in the winding drum portion 31a. Assuming that the terminal of the belt 3, which is fixed to the belt pin 32 of the belt 3, is engaged with the entrance portion of one end of the one of the through holes 31f, the belt 3 is sequentially turned to the two through holes 31f. It may be threaded and wound around the outer circumference of the winding drum portion 31a.

In the embodiment shown in FIGS. 8 and 9, the end of the belt 3 is not fixed inside the spool 31, but passes through a radial through-hole 31f formed inside the spool 31. , the belt 3 is double-wound on the outer periphery of the winding drum part 31a of the spool 31, and in an emergency such as a worker falling, the belt 3 is simultaneously pulled out from the spool 31 in both directions as the spool 31 rotates . .

In this embodiment , although the application location is limited, if the length of the shaft portion 30a of the torsion bar 30 is the same as that of the first embodiment, a double buffer stroke can be obtained. Even if the length of the shaft portion 30a is halved, the same cushioning stroke as that of the first embodiment can be obtained, the size and weight can be reduced, and the belt pin can be eliminated.

Also, the shock absorber described in the above reference form may be arranged in series with the winder, for example, as shown in FIGS. can.

The winder in the first embodiment of this fall arrest device is urged in the winding direction so that the wound belt can be pulled out at any time, and when the worker falls from a high place and the strap 1 is rapidly unwound, A locking mechanism having a swinging pawl 14 prevents the strap 1 from being extended. The attached strap pin 13 is held inside the spool 11, but does not serve as a rotation support shaft of the spool, and the strap 1 is wound around the outer periphery of the spool 11 via the inside.

Such a fall arrest device can share the same parts for the winder and the shock absorber, so it is compact and easy to handle while having both functions, and has a stable load that is not affected by the usage environment. It will have characteristics.

13, the winder has two spools 11 arranged in parallel, and the winder and the shock absorber are integrated by a base 12. It may be housed in the case 41 at the same time.

With such a configuration, when a worker moves a long distance, before removing the hook at the tip of the strap 1 unwound from one spool 11 from the structure, the strap 1 unwound from the other spool 11 is removed. Since the hook at the tip can be hung at a position separated in the moving direction of the structure, it is possible to improve safety while achieving compactness.

1 straps 3, 4 belt 11 spool 12 base 12c fitting hole 12d receiving plate portion 12e locking hole 13 strap pin 14 pawl 20a bolt 20b spacer 23 screw 30 torsion bar 30a shaft portion 30b locking end portion 31 spool 31a winding drum portion 31b Flange 31c Fitting portion 31d Core hole 31e Locking recess 31f Intermediate hole 32 Belt pin 33 Frame ring 34 End plate member 35 Screw 36a Guide roller 36b Rotary shaft 37 Connection pin 41 Case 41b Base receiving portion

Claims (3)

A shock absorber for a safety belt, which is provided in a safety belt worn by a worker who works at height, and which mitigates the impact acting on the worker in an emergency via the belt (3),
The end of the belt (3) is not fixed to the inside of the spool (31) rotatably held by being sandwiched between the opposing bases (12). It penetrates through the through hole (31f) and is double wound around the outer periphery of the spool (31),
One locking end (30b) of the torsion bar (30) is locked to one end of the spool (31) so as to rotate together, and the other locking end ( 30b ) of the torsion bar (30) is locked. ) is locked to one of the bases (12) so as not to rotate,
In an emergency, as the spool (31) rotates, the belt (3) is pulled out from the spool (31) in both directions at the same time. A shock absorber for a safety belt, characterized in that the shaft portion (30a) of the bar (30) is twisted to reduce the impact acting on the worker. A fall arrest device for a safety belt worn by a worker working at height, comprising a winder integrated with a shock absorber,
The shock absorber mitigates the impact acting on the worker in an emergency via the belt (3),
The belt (3) is wound around the outer periphery of a spool (31) rotatably held between opposing bases (12), and one end of the spool (31) is attached to one end of a torsion bar (30). The locking end (30b) of the torsion bar (30) is locked so as to rotate together, and the other locking end (30b) of the torsion bar (30) is connected to one of the bases (12). locked to prevent it from rotating,
In an emergency, the belt (3) pulls out from the spool (31) to twist the shaft (30a) of the torsion bar (30), thereby mitigating the impact on the worker. ,
The winding device is urged in the winding direction so that the wound strap (1) can be pulled out at any time, and in an emergency, the strap (1) is prevented from being pulled out by a lock mechanism,
A spool (11) for winding the strap (1) is rotatably held by being sandwiched between opposing bases (12) shared with the shock absorber,
A strap pin (13) to which the end of the strap (1) is attached is held inside the spool (11), but does not serve as a rotation support shaft for the spool (11).
A fall arrest device for a safety belt, wherein the strap (1) is wound around the outer circumference of the spool (11) from the strap pin (13) via the inside of the spool (11). 2. The spools (11, 31) of the winder and the shock absorber are held in the thrust direction by fastening the opposing bases ( 12 ) while maintaining a space therebetween. fall arrest device for the safety belt described in .

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