Equipment to prevent workers from falling

Abstract

To provide fall prevention equipment for workers, capable of protecting workers working on transportation vehicles even at positions behind rear wheels.SOLUTION: Fall prevention equipment for workers comprises an auxiliary arm 40 formed to be extendable further rearward of a rear wheel-side support 30. The auxiliary arm 40 includes: a vertical support plate 43; a plurality of claw parts 41 and 42 with respective base ends fixed to one side of the support plate 43 and with clamps 41a and 42a fixed to a support body 35 at the respective ends; an upright part 44 protruding from the other surface of the support plate 43; a hinge part 45 disposed on the upright part 44; cylindrical bodies 46 and 47 with base end parts pivotally supported by the hinge part 45 and extending rearward of a loading platform 4; and a locking ring 47a to be fixed to tips of the cylindrical bodies 46 and 47. The locking ring 47a includes a safety belt locked thereto, the safety belt to be connected to a worker 50, and when a weight of the worker 50 acts on the safety belt 51, the support body 35 is plastically deformed to reduce the impact acting on the worker 50.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a fall prevention system for workers, and in particular to a system that uses a type of support pole having a base portion that is pressed down by the wheels of a transport vehicle and wheels that are rotatably attached to the base portion. [Background technology]

[0002] When work is carried out on the loading platform of a transport vehicle (truck, trailer, etc.), equipment to prevent workers from falling should be installed so that they can wear safety harnesses to ensure their safety.

[0003] In order to effectively use the safety belt that connects to the worker's body, the lifeline must be tensioned at a level higher than the loading platform, and therefore a lifeline support pole must be placed above the loading platform.

[0004] Such supports can be broadly divided into two types. First, as described in Patent Document 1 (JP 2019-208792 A), there is a type 1 support that does not allow the wheels of a transport vehicle to press down on the lower end of the support. This type 1 is premised on the use of a very large and heavy base plate, and requires extremely strong force or heavy machinery to move or transport the support.

[0005] In contrast, the second type of support pillar to which the present invention relates belongs to a type in which the flat plate of the support pillar is pressed down by the wheels of a transport vehicle, as disclosed in Patent Document 2 (JP Patent Publication No. 2011-291863).This second type of support pillar is often equipped with additional wheels, as disclosed in Patent Document 3 (JP Patent Publication No. 2017-71951), to make it easier to move and transport the pillar.

[0006] On the other hand, as shown in Patent Document 2, in a worker fall prevention device that uses a second type of support, the main rope is held at a high level in the area from the front of the transport vehicle to the support that is held down by the rear wheels, and by connecting the safety belt to the main rope, the worker can be protected from falling.

[0007] However, further behind the rear wheels, the lifeline gradually becomes lower, almost to the level of the loading platform. In actual work, workers often move behind the rear wheels to perform their work. In other words, conventional worker fall prevention equipment has the problem that protection is weak in the area behind the rear wheels, and worker safety is not sufficiently ensured. [Patent Document 1] Japanese Patent Application Publication No. 2019-208792 [Patent Document 2] Japanese Patent Application Publication No. 11-291863 [Patent Document 3] Japanese Patent Application Laid-Open No. 2017-71951 DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0008] Therefore, an object of the present invention is to provide a fall prevention system for workers that can protect workers working on transport vehicles even at positions behind the rear wheels. [Means for solving the problem]

[0009] The worker fall prevention equipment according to the first invention comprises a front wheel side support having a first base portion that is pressed down on by the front wheel of a transport vehicle, a first wheel that is rotatably attached to the first base portion, a first support body that stands vertically from the first base portion, and a first locking ring that is arranged on the top of the first support body; a rear wheel side support having a second base portion that is pressed down on by the rear wheel of the transport vehicle, a second wheel that is rotatably attached to the second base portion, a second support body that stands vertically from the second base portion, and a second locking ring that is arranged on the top of the second support body; a life rope that is locked at one end to the first locking ring, has its middle inserted into the second locking ring, and its other end lowered from the middle to be fixed to the rear end of the bed of the transport vehicle; a tensioner that applies tension to the life rope; and a second support and an auxiliary arm fixed to the upper part of the main body and formed so as to be extendable above the loading platform further rearward than the rear wheel side support pillar, the auxiliary arm comprising a vertical support plate, a plurality of claw portions each having a base end fixed to one side of the support plate and a clamp at each tip end which is fixed to the second support pillar body, an upright portion protruding from the other side of the support plate in the opposite direction to the plurality of claw portions, a hinge portion disposed on the upright portion, a cylindrical body whose base end is pivotally supported by the hinge portion and which extends to the rear of the loading platform, and a third locking ring fixed to the tip end of the cylindrical body, one end of which is connected to the worker and the other end of the safety belt is locked to the third locking ring, and when the worker's weight acts on the safety belt and the safety belt becomes taut, the second support pillar body undergoes plastic deformation to absorb the impact acting on the worker.

[0010] In this configuration, the lifeline is held at a high level between the first and second locking rings, in other words, between the front and rear wheels of the transport vehicle, but further behind the rear wheels it drops down and eventually reaches the same level as the loading platform.

[0011] However, by extending the auxiliary arm further rearward than the rear wheel, the position of the safety belt can be kept high to protect the worker even in areas where the lifeline is low. On the other hand, the hinge part can be used to rotate the cylinder so that it faces forward more than the rear wheel, allowing the worker to work while being protected over a wide area by the safety belt and auxiliary arm.

[0012] Furthermore, by fastening the clamps with multiple claws to the top of the second support body and firmly supporting the third locking ring with the multiple claws, support plate, and cylinder, the safety belt can be supported with sufficient strength for practical use.

[0013] If a worker falls, the safety belt tightens and the second support body undergoes plastic deformation, dissipating energy and absorbing the impact on the worker. In this case, the rear wheel support can no longer be used and must be replaced with a new rear wheel support.

[0014] The second invention relates to a worker fall prevention device provided on the loading platform of a transport vehicle, which, in addition to the first invention, has an outrigger attached to the front wheel support pillar to reinforce the front wheel support pillar.

[0015] With this configuration, the strength of the front wheel side support pillar can be increased, and only the second support pillar body of the rear wheel side support pillar can be plastically deformed.

[0016] The worker fall prevention equipment according to the third invention is, in addition to the features of the first invention, characterized in that the cylindrical body has an outer cylindrical body whose base end is pivotally supported by a hinge portion, an inner cylindrical body that is slidably inserted into the interior of the outer cylindrical body, and a pin that fixes the sliding position of the outer cylindrical body and the inner cylindrical body.

[0017] In this configuration, by extending the inner cylindrical body relative to the outer cylindrical body and fixing it with a pin, the range in which the worker can move can be further expanded. [Effects of the Invention]

[0018] According to the present invention, a worker can be effectively protected using a safety belt and auxiliary arm even at a position further rearward than the rear wheels of a transport vehicle. Furthermore, even if the worker falls, the safety belt tightens and the second support body undergoes plastic deformation, consuming energy and mitigating the impact on the worker. BEST MODE FOR CARRYING OUT THE INVENTION

[0019] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a side view of a worker fall facility according to an embodiment of the present invention, Figs. 2, 3, and 4 are front views showing the rear wheel side support pillar and auxiliary arm according to an embodiment of the present invention, and Figs. 5(a), 5(b), and 5(c) are plan views showing the rear wheel side support pillar and auxiliary arm according to an embodiment of the present invention.

[0020] As shown in Figure 1, a transport vehicle 1 such as a truck or trailer has front wheels 2 and rear wheels 3, which come into contact with the ground. Although the vehicle shown in the figure has only one front wheel 2 and one rear wheel 3, the vehicle may have two or more wheels, and in that case, the wheel that presses down on the base of the support pole can be selected as desired. In the example shown in the figure, a loading platform 4 is located from a position slightly behind the front wheels 2 to a position behind the rear wheels 3.

[0021] The front wheel side support 10 has a frame body 11, a base part 12 disposed at the bottom of the frame body 11 and pressed down by the front wheel 2, a wheel 14 journalled to the frame body 11 and attached rotatably to the base part 12, and a support body 15 standing vertically from the base part 12. A plurality of (three in this example) locking rings 16 are arranged on the top of the support body 15 so that the height at which the life rope 20 is stretched can be selected.

[0022] In addition, an outrigger 17 is fixed to the bottom of the front wheel side support 10, and the support body 15 is reinforced by the outrigger 17.

[0023] The rear wheel side support 30 has a frame body 31, a base part 32 disposed at the bottom of the frame body 31 and pressed down by the rear wheel 3, a wheel 34 journalled to the frame body 31 and attached rotatably to the base part 32, and a support body 35 standing vertically from the base part 32. A plurality of (three in this example) locking rings 36 are arranged on the top of the support body 35 so that the height at which the life rope 20 is stretched can be selected.

[0024] In the example shown in Figure 1, the highest of the locking rings 16, 36 is selected. The hook 21 at one end of the life rope 20 is locked to the selected locking ring 16, and the life rope 20 is stretched horizontally. The life rope 20 is then passed through the selected locking ring 36 of the rear wheel support 30, and then lowered and connected to the rear end of the cargo bed 4. In the example shown, the tensioner 22 is located at the rear end of the cargo bed 4, but the tensioner 22 can be located in any position as long as it can apply tension to the life rope 20.

[0025] An auxiliary arm 40 is provided above the loading platform 4 so as to be extendable further rearward than the rear wheel-side support 30. A hook 51a located at the end of a belt part 51b extending from an attachment part 51c of the worker 50 is engaged with a locking ring 47a (see FIG. 2) at the tip of the auxiliary arm 40.

[0026] The auxiliary arm 40 will be described in detail below with reference to Figures 2 to 5. The auxiliary arm 40 has a vertical support plate 43. The base ends of a first claw portion 41 and a second claw portion 42 are fixed to one surface of the support plate 43 (the surface on the left side in Figure 2), and clamps 41a and 42a are provided at the tip ends of the first claw portion 41 and the second claw portion 42, which are fixed to the upper part of the support main body 35. In the example shown in Figure 2, there are two claw portions 41 and 42, but three or more may be used.

[0027] On the other surface of support plate 43 (the surface on the right side in FIG. 2), an upright portion 44 is provided that protrudes in the opposite direction to claw portions 41 and 42, and a hinge portion 45 is housed in upright portion 44. Furthermore, the base end of the cylinder, which is made up of an outer cylinder 46 and an inner cylinder 47, is pivotally supported by hinge portion 45.

[0028] The internal cylinder body 47 is inserted inside the external cylinder body 46 in a nested state so as to be able to slide freely, and the positional relationship in the sliding direction can be fixed by inserting a pin 48 protruding from the external cylinder body 47. Figure 2 shows the state in which the internal cylinder body 47 is at its innermost position (shortened). When the internal cylinder body 47 is extended from this state and fixed again with the pin 48, it becomes the state shown in Figure 3.

[0029] As described above, the base end of the external cylinder body 46 is pivotally supported by the hinge portion 45, allowing the auxiliary arm 40 to swing within a horizontal plane. That is, in a plan view, the auxiliary arm 40 can be oriented rearward from the rear wheel 3 as shown in FIG. 5(b), or perpendicular to the rear wheel 3 as shown in FIG. 5(a), resulting in the state shown in FIG. 4. Furthermore, the auxiliary arm 40 can be oriented forward from the rear wheel 3 as shown in FIG. 5(c). As shown in FIG. 5, the base portion 32 is configured by overlapping a base plate 32a and a vehicle tread 32b, and both edges of the vehicle tread 32b are bent to form reinforcing edges 32c.

[0030] In addition, as described above, increasing the length of the auxiliary arm 40 can expand the area that can be covered by the auxiliary arm 40. Within this area, the worker 50 is protected by the safety belt 50, the auxiliary arm 40, and the rear wheel-side support 30.

[0031] Next, we will introduce an example of moment calculation using the model shown in Figure 8. Here, we assume that there is one worker 50, the load is P = 100 (Kg), and the load coefficient is 15 (%), i.e., the impact load is 115 (Kg).

[0032] The base portion 32 has a cross-sectional area A = 49.12 (cm 2 ), moment of inertia I = 44.324 (cm 4 ), section modulus z = 31.66 (cm 3 ), Young's modulus E = 2.1 × 10 6 (Kg / cm 2 )

[0033] For the support body 35, the cross-sectional area A = 4.025 (cm 2 ), moment of inertia I = 17.8 (cm 4 ), section modulus z = 5.9 (cm 3 ), Young's modulus E = 2.1 × 10 6 (Kg / cm 2 )

[0034] The moment and the like related to the base portion 32 are as follows: Maximum moment Mmax=115 (Kg)×350 (cm)=40250 (Kgcm), bending stress δb=Mmax / Z=40250 (Kgcm) / 31.66 (cm 3 )=1271.3(Kg / cm 2 ) <fb=1600(Kg / cm 2 ) and there is no problem.

[0035] For the support body 35, the maximum moment Mmax = 115 (Kg) × (350 - 50 (cm)) = 34,500 (Kgcm), and the bending stress δb = Mmax / Z = 34,500 (Kgcm) / 5.9 (cm 3 )=5847.5(Kg / cm 2 )>F value = 2400 (Kg / cm 2 ) and it exceeds the elastic deformation region and belongs to the plastic deformation region.

[0036] Next, the operation when a fall accident occurs will be described with reference to Figures 1, 6 and 7. First, as shown in Figure 1, assume that a worker 50 is working further rearward than the rear wheel 3. In this case, with the prior art, the life rope 20 is too low and there is no way to protect the worker 50.

[0037] Next, if the worker 50 slips and falls, as shown in Figure 6, the weight of the worker 50 acts on the belt portion 51b of the safety belt 51, causing tension to act on the safety belt 51. At this time, a moment is applied as described in the above calculation example, and the support body 35 of the rear wheel side support 30 undergoes plastic deformation, as shown in Figure 7. On the other hand, the front wheel side support 10 is reinforced by the provision of the outrigger 17, so it is hardly deformed.

[0038] When the support pillar body 35 is plastically deformed, the energy is absorbed accordingly, and as a result, the damage to the worker 50 is mitigated. This makes it possible to reduce the harm to the worker 50. Note that a rear wheel side support pillar that has been plastically deformed cannot be used continuously, so it must be replaced with a new product after deformation. [Brief explanation of the drawings]

[0039] [Figure 1] 1 is a side view of a worker fall facility according to an embodiment of the present invention; [Figure 2] FIG. 1 is a front view showing a rear wheel side support pillar and an auxiliary arm according to an embodiment of the present invention. [Figure 3] FIG. 1 is a front view showing a rear wheel side support pillar and an auxiliary arm according to an embodiment of the present invention. [Figure 4] FIG. 1 is a front view showing a rear wheel side support pillar and an auxiliary arm according to an embodiment of the present invention. [Figure 5] (a) Plan view showing a rear wheel side support pillar and an auxiliary arm in one embodiment of the present invention. (b) Plan view showing a rear wheel side support pillar and an auxiliary arm in one embodiment of the present invention. (c) Plan view showing a rear wheel side support pillar and an auxiliary arm in one embodiment of the present invention. [Figure 6] 1 is a side view of a worker fall facility according to an embodiment of the present invention; [Figure 7] 1 is a side view of a worker fall facility according to an embodiment of the present invention; [Figure 8] A model diagram of a rear wheel side support and an auxiliary arm according to one embodiment of the present invention. [Explanation of symbols]

[0040] 1 Transport vehicle 2 front wheels 3 rear wheels 4 Cargo bed 10 Front wheel support 11 Frame 12 Base 13 Shaft 14 wheels 15 Pillar body 16 Locking ring 17 Outrigger 20 Main rope 21 Hook 22 Tension machine 30 Rear wheel side strut 31 Frame 32 Base 32a base plate 32b Wheel tread 32c reinforced edge 33 Shaft 34 wheels 35 Pillar body 36 Locking ring 40 Auxiliary Arm 41 1st claw part 41a First clamp 42 2nd claw part 42a Second clamp 43 Support plate 44 Standing part 45 Hinge part 46 Outer tube 47 Inner tube 47a Locking ring 48 pins 50 workers 51 Safety Belt 51a Hook 51b Belt section 51c Mounting part

Claims

1. a front wheel side support having a first base portion that is pressed down by the front wheel of the transport vehicle, a first wheel that is rotatably attached to the first base portion, a first support body that stands vertically from the first base portion, and a first locking ring that is disposed on an upper portion of the first support body; a rear wheel side support having a second base portion that is pressed down by the rear wheel of the transport vehicle, a second wheel that is rotatably attached to the second base portion, a second support body that stands vertically from the second base portion, and a second locking ring that is arranged on an upper portion of the second support body; a life rope having one end engaged with the first locking ring, a middle portion inserted into the second locking ring, and the other end descending from the middle portion to be fixed to the rear end portion of the bed of the transport vehicle; a tensioning device that applies tension to the life rope; an auxiliary arm fixed to an upper portion of the second support pillar body and formed to be extendable above the bed further rearward than the rear wheel side support pillar, The auxiliary arm is a vertical support plate; a plurality of claws, each having a base end fixed to one surface of the support plate and a clamp at a tip end fixed to the second support body; an upright portion protruding from the other surface of the support plate in a direction opposite to the plurality of claw portions; a hinge portion disposed on the upright portion; a cylindrical body whose base end is pivotally supported by the hinge portion and extends rearward of the loading platform; a third locking ring fixed to the tip end of the cylindrical body; The third locking ring is connected to one end of a safety belt, the other end of which is connected to a worker, When the worker's weight acts on the safety belt and the safety belt becomes taut, the second support body undergoes plastic deformation, thereby absorbing the impact acting on the worker.

2. 2. The fall prevention system for workers according to claim 1, wherein an outrigger is attached to the front wheel side support pillar to reinforce the front wheel side support pillar.

3. 2. The worker fall prevention equipment according to claim 1, wherein the cylindrical body comprises an outer cylindrical body whose base end is pivotally supported by the hinge portion, an inner cylindrical body that is slidably inserted into the interior of the outer cylindrical body, and a pin that fixes the sliding position of the outer cylindrical body and the inner cylindrical body.

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