Fall prevention equipment for workers

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 equipment for preventing workers from falling, and in particular to equipment that uses a type of support that has 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 will 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 stretched at a level higher than the loading platform, and therefore a support pole for the lifeline 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 Patent Publication No. 2019-208792), there is a type 1 support in which the lower end of the support is not pressed down by the wheels of the transport vehicle. This first type is based on the premise of using 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 to which the present invention relates belongs to a type in which the flat plate of the support 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 is often equipped with additional wheels to make it easier to move and transport, as disclosed in Patent Document 3 (JP Patent Publication No. 2017-71951).

[0006] On the other hand, as shown in Patent Document 2, in a worker fall prevention equipment that uses the second type of support, the life rope is held at a high level in the area from the front of the transport vehicle to the support pole that is held down by the rear wheels, and by connecting the safety belt connected to the worker to the life 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, the conventional equipment for preventing workers from falling has a problem in that protection is weak in the area behind the rear wheels, and the safety of workers is insufficient. [Patent Document 1] JP 2019-208792 A [Patent Document 2] Japanese Patent Application Publication No. 11-291863 [Patent Document 3] JP 2017-71951 A DISCLOSURE OF THEINVENTION [Problem to be solved by the invention]

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

[0009] The worker fall prevention equipment according to the first invention includes a front-wheel side support having a first base portion that is pressed down against 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 an upper portion of the first support body, a rear-wheel side support having a second base portion that is pressed down against 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 that is locked to the first locking ring, a middle portion that is inserted into the second locking ring, and the other end that is lowered from the middle portion and 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 to be extendable further rearward than the rear wheel side support above the loading platform, 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 end fixed to the second support 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 extending to the rear of the loading platform, and a third locking ring fixed to the tip of the cylindrical body, the other end of a safety belt whose other end is connected to a worker being 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 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 cargo bed.

[0011] However, by extending the auxiliary arm further rearward than the rear wheels, the position of the safety belt can be kept high to protect the worker even in the range 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 wheels, allowing the worker to work while being protected by the safety belt and auxiliary arms over a wide range.

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

[0013] When a worker falls, the safety belt tightens and the second support body undergoes plastic deformation to consume energy, mitigating the impact on the worker. In this case, the rear wheel support cannot be used continuously and will be replaced with a new rear wheel support.

[0014] The second invention relates to worker fall prevention equipment provided on the bed of a transport vehicle, in addition to the features of the first invention, in which an outrigger is attached to the front wheel side support pillar to reinforce the front wheel side support pillar.

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

[0016] The worker fall prevention equipment of 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 the hinge portion, an inner cylindrical body that is slidably inserted into the inside 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 cylinder body relative to the outer cylinder body and fixing it with a pin, the range in which the worker can move can be further expanded. Effect of the Invention

[0018] According to the present invention, the worker can be effectively protected by the safety belt and the auxiliary arm even at a position further rearward than the rear wheels of the transport vehicle. Even if the worker falls, the safety belt is taut and the second support body undergoes plastic deformation to consume energy, thereby mitigating the impact on the worker. BEST MODE FOR CARRYING OUT THEINVENTION

[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 equipment in one embodiment of the present invention, Figs. 2, 3, and 4 are front views showing the rear wheel side support pillar and auxiliary arm in one 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 in one embodiment of the present invention.

[0020] As shown in Fig. 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, in which case the wheels that press 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 portion 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 portion 12, and a support body 15 standing vertically from the base portion 12. A number of locking rings 16 (three in this example) are arranged on the upper portion 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 locking rings 36 (three in this example) are arranged on the upper part 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 Fig. 1, of the locking rings 16, 36, the one in the highest position is selected. A 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 inserted through the selected locking ring 36 of the rear wheel side support 30, and then lowered and connected to the rear end of the cargo bed 4. In the example shown, the tensioner 22 is disposed at the rear end of the cargo bed 4, but the tensioner 22 can be disposed 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 and is formed so as to be extendable further rearward than the rear wheel-side support pillar 30. A hook 51a located at the end of a belt part 51b extending from an attachment part 51c of a 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 Figs. 2 to 5. The auxiliary arm 40 has a vertical support plate 43. The base ends of the first claw portion 41 and the second claw portion 42 are fixed to one surface of the support plate 43 (the surface on the left side in Fig. 2), and clamps 41a, 42a are provided at the tips of the first claw portion 41 and the second claw portion 42, which are fixed to the upper part of the pillar main body 35. In the example shown in Fig. 2, there are two claw portions 41, 42, but three or more may be used.

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

[0028] The inner cylinder body 47 is inserted inside the outer 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 outer cylinder body 47. Fig. 2 shows the state in which the inner cylinder body 47 is at its innermost position (shortened). When the inner cylinder body 47 is extended from this state and fixed again with the pin 48, it becomes the state shown in Fig. 3.

[0029] As described above, the base end of the external cylinder body 46 is pivoted by the hinge portion 45, so that the auxiliary arm 40 can be swung in a horizontal plane. That is, in a plan view, as shown in FIG. 5(b), the auxiliary arm 40 can be oriented rearward from the rear wheel 3, or as shown in FIG. 5(a), the auxiliary arm 40 can be oriented perpendicular to the rear wheel 3, in which case the auxiliary arm 40 is in the state shown in FIG. 4. Furthermore, as shown in FIG. 5(c), the auxiliary arm 40 can be oriented forward from the rear wheel 3. 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 folded to form reinforcing edges 32c.

[0030] In addition, as described above, by increasing the length of the auxiliary arm 40, it is possible to expand the area that the auxiliary arm 40 can cover. 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] For the base portion 32, the cross-sectional area A = 49,12 (cm 2 ), moment of area 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 area 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 column body 35, the maximum moment Mmax = 115 (Kg) × (350 - 50 (cm)) = 34500 (Kgcm), the bending stress δb = Mmax / Z = 34500 (Kgcm) / 5.9 (cm 3 )=5847.5(Kg / cm 2 )>F value = 2400 (Kg / cm 2 ) which exceeds the elastic deformation region and belongs to the plastic deformation region.

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

[0037] Next, when the worker 50 slips and falls, as shown in Fig. 6, the weight of the worker 50 acts on the belt portion 51b of the safety belt 51, and tension acts on the safety belt 51. At this time, a moment is applied as described in the above calculation example, and the pillar body 35 of the rear wheel side pillar 30 is plastically deformed as shown in Fig. 7. On the other hand, the front wheel side pillar 10 is hardly deformed because it is reinforced by the provision of the outrigger 17.

[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 suppress the harm to the worker 50. Note that the 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 description of the drawings]

[0039] [Figure 1] 1 is a side view of a worker fall facility according to an embodiment of the present invention; [Diagram 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; [Diagram 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; [Diagram 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 pillar and an auxiliary arm in one embodiment of the present invention. [Explanation of symbols]

[0040] 1. Transport vehicles 2 Front wheels 3 Rear wheel 4 Cargo platform 10 Front wheel support 11 Frame 12 Base section 13 Shaft 14 wheels 15 Pillar body 16 Locking ring 17 Outrigger 20 Lifeline 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 pin 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 a 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 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 a 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 disposed on an upper portion of the second support body; a lifeline having one end engaged with the first locking ring, a middle portion inserted into the second locking ring, and another end portion lowered from the middle portion to be fixed to a rear end portion of the bed of the transport vehicle; A tensioner that applies tension to the life rope; an auxiliary arm that is fixed to an upper portion of the second support pillar body and is formed to be extendable further rearward than the rear wheel side support pillar above the loading platform, 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 fixed to the second support body at a tip end; a standing 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 having a base end pivotally supported by the hinge portion and extending rearward of the loading platform; a third locking ring fixed to a tip end of the cylindrical body; The third locking ring is engaged with one end of a safety belt, the other end of which is connected to a worker, This worker fall prevention equipment is characterized in that when the weight of the worker 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 worker fall prevention system according to claim 1, wherein an outrigger is attached to the front wheel side support pillar for reinforcing the front wheel side support pillar.

3. 2. The worker fall prevention equipment as described in claim 1, wherein the cylindrical body includes an outer cylindrical body whose base end is pivotally supported by the hinge portion, an inner cylindrical body that is slidably inserted into the inside of the outer cylindrical body, and a pin that fixes the sliding positions of the outer cylindrical body and the inner cylindrical body.

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