JP7655671B2 - Movable anti-constriction mechanism for lifting device - Google Patents

Description

The present invention relates to a lifting device that is embedded in a factory pit, and to a technology that prevents parts of the body from getting caught in the gap between the pit and the lifting device.

In vehicle maintenance factories and the like, a pit is dug in the factory floor and a lifting device is installed inside it. When this is done, gaps are formed between the edge of the pit and parts of the lifting device, such as the table and the arm used to lift the table, which can cause parts of the worker's body to unintentionally get stuck in the gap, creating a risk of interference when lowering the lifting device or falling into the pit. The following countermeasures are known for such deeply excavated areas in the work environment, such as pits and manholes.

Patent Document 1 discloses technology related to a manhole safety fence device. This technology provides a retractable safety fence that can be raised and lowered to prevent people from falling into a manhole unintentionally when the manhole cover is opened. When the safety fence is pulled out from inside the manhole, the outriggers rotate outward by the springs, locking the safety fence onto the top surface of the manhole. Therefore, when the manhole cover is left open to use the manhole, the safety fence is pulled out, preventing people from accidentally falling into the manhole.

Patent Document 2 discloses technology related to fall prevention devices. This technology involves installing an air tube along the side edge of the vehicle in the gap between the roof-top inspection scaffolding installed for inspecting the roof of a railway vehicle and the vehicle roof, and connecting this air tube to an air-inflating device to inflate the air tube. This makes it possible to prevent people or objects from falling through the gap between the roof-top inspection scaffolding and the vehicle roof.

JP 2019-124055 A JP 2018-102444 A

Therefore, while it may seem that using technologies such as those in Patent Document 1 and Patent Document 2 would be able to close the gap between the factory pit and the lifting device and prevent parts of the body from getting stuck in the gap between the pit and the lifting device, there are the following problems when trying to apply them simply. First, when using the technology in Patent Document 1, the pit needs to be deep enough to accommodate a fence with the same height as the lifting height of the lifting device, and it cannot be used for shallow pits. In addition, while the technology in Patent Document 2 is expected to be effective in preventing people from falling into the pit, it is not easy to inflate the air tube in the vertical direction to prevent people's bodies from getting stuck between the pit and the lifting device.

There are other issues as well. In general, for example, when maintaining railroad cars or their parts in a factory, the work is often lifted up and the worker works facing upwards or at eye level, and attention to what is under their feet tends to be distracted. In addition, when the lifting device is not moving, the nature of the work may make it difficult to work if some part of the body is not allowed to enter the space between the pit and the lifting device. Therefore, there may be cases where a safety fence like that in Patent Document 1, which prevents part of the body from entering the space between the pit and the lifting device, is inconvenient. In addition, air tubes like those in Patent Document 2 require height to cover the gap under the lifting device, making them difficult to store and difficult to use in shallow pits.

For these reasons, it is possible to simply install a fixed safety fence around the pit, but this would interfere with work when the lifting device is stored under the floor. This is because when moving rail cars or their parts, the difference in floor levels requires lifting them up. Also, when creating a pit in the floor of an existing factory, it is less costly to make the pit as shallow as possible, so a retractable safety fence that can accommodate shallow pits was eagerly awaited on site.

The present invention aims to solve these problems and provide a movable constriction prevention mechanism for an elevator that can prevent any part of the body from getting stuck between the shallow pit and the elevator.

To achieve the above objective, the movable constriction prevention mechanism for a lifting device according to one aspect of the present invention has the following features:

(1) A movable constriction prevention mechanism for an elevator device that is adapted to be housed inside a pit provided on a floor surface,
A constriction prevention plate is provided along the inner wall surface of the pit so as to be capable of rising and falling, and a movable mechanism for raising and lowering the constriction prevention plate,
The height dimension of the constriction prevention plate protruding from the floor surface is lower than the height dimension of the lifting device in a folded state when the upper table of the lifting device is at the lower end,
When the upper table is at the lower end, the upper surface of the constriction prevention plate is pressed by the lower surface of the upper table, so that the constriction prevention plate is contained inside the pit,
When the upper table is at the upper end, the constriction prevention plate is pushed up by the movable mechanism to rise to the upper end position;
The constriction prevention plate is disposed on the inner periphery of the pit without any gap;
When the constriction prevention plate protrudes from the floor surface, the lower end of the constriction prevention plate is located below the floor surface;
It is characterized by:

The aspect described in (1) above makes it possible to raise and lower the constriction prevention plate even in a shallow pit, and to store the constriction prevention plate in the pit. When performing maintenance on a railway vehicle and its parts that have been lifted by a lifting device, the worker will inevitably lose attention to what is beneath his feet. However, at the very least, it is sufficient to prevent the tips of the feet from entering the inside of the pit from the edge, and the height of the constriction prevention plate itself does not need to be very high. This is because, as stated in the problem section, when a worker works on a workpiece that has been lifted up by a lifting device, he or she tends to lose attention to what is beneath his or her feet.

Conversely, by providing an anti-constriction plate as a measure for the feet, it is possible to improve safety for the work vehicle. Therefore, the purpose can be fully achieved by raising and lowering an anti-constriction plate that is lower than the height dimension of the lifting device in the folded state. Since the height of the anti-constriction plate is not required, it can be stored even in a shallow pit, and since the anti-constriction plate is stored inside the pit when the upper table is at the lower end, the anti-constriction plate does not get in the way of work when not in use.

(2) In the movable constriction prevention mechanism for a lifting device according to (1),
The constriction prevention plate is made of a hard material, and the movable mechanism uses a gas spring type cylinder.
is preferred.

In the aspect described in (2) above, the structure of the movable constriction prevention mechanism for a lifting device can be simplified and costs can be reduced, so that, for example, even when an underfloor storage type lifting device equipped with a movable constriction prevention mechanism for a lifting device is adopted in an existing factory, it can be adopted at low cost. By using a gas spring type cylinder for the movable mechanism, the constriction prevention plate can be lifted without requiring power. In addition, by limiting the height of the constriction prevention plate to a level that prevents the worker's toes from going over the edge of the pit, the stroke of the cylinder can be shortened and the depth of the pit is not required. As a result, it is possible to adopt the movable constriction prevention mechanism for a lifting device at low cost.

(3) A movable constriction prevention mechanism for an elevator device that is accommodated in a pit provided on a floor surface,
A constriction prevention plate is provided along the inner wall surface of the pit so as to be capable of rising and falling, and a movable mechanism for raising and lowering the constriction prevention plate,
The height dimension of the constriction prevention plate protruding from the floor surface is lower than the height dimension of the lifting device in a folded state when the upper table of the lifting device is at the lower end,
When the upper table is at the lower end, the upper surface of the constriction prevention plate is pressed by the lower surface of the upper table, so that the constriction prevention plate is contained inside the pit,
When the upper table is at the upper end, the constriction prevention plate is pushed up by the movable mechanism to rise to the upper end position;
The upper end of the bellows-type anti-constriction membrane is fixed to the lower surface of the upper table,
The anti-constriction membrane expands and contracts as the upper table rises and falls.
The anti-constriction membrane is made of a flexible material, and a worker can work by placing part of his/her body under the upper table.
The constriction prevention plate is made of a material harder than the constriction prevention film and protects the feet of the worker.
is preferred.

In the aspect described in (3) above, the protrusion of the constriction prevention plate serves to prevent part of the body from getting into the gap between the pit and the lifting device under the worker's feet, and the constriction prevention membrane serves to prevent part of the body from getting into the gap between the pit and the lifting device above the upper end of the constriction prevention plate. Since the area covered by the constriction prevention membrane is within the worker's field of vision, the level of constriction prevention effect required is lower than that of the lower part, but providing the constriction prevention membrane can contribute to further improving the safety of the worker while working.

FIG. 2 is a plan view of the lifting device according to the embodiment. This is a front view of the lifting device of this embodiment that fits within a pit. This is a side view of the lifting device of this embodiment that fits within a pit. FIG. 2 is a side view illustrating a pantograph arm portion of the lifting device in this embodiment. FIG. 2 is a side view of the lifting device in the folded state according to the embodiment.

First, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 shows a plan view of the lifting device 100 of this embodiment. Fig. 2 shows a front view of the lifting device 100 that fits within the pit 20. Fig. 3 shows a side view of the lifting device 100 that fits within the pit 20. The lifting device 100 is a type of device with lifting and lowering functions called a table lift, etc., and is housed in a pit 20 provided on the floor surface 10 of a factory. An object to be lifted up, such as a railway vehicle or its parts, can be placed on the upper table 101 of the lifting device 100 and raised and lowered.

A pantograph arm 105 is provided below the upper table 101. The pantograph arm 105 is arranged so that a pair of left and right first arms 105a and a pair of left and right second arms 105b cross each other, and the left and right first arms 105a and second arms 105b are supported rotatably at approximately their centers. The upper end of the first arm 105a is supported on the upper table 101 side, one of the lower ends is supported on the base 102 side so as to be able to move in parallel, and the other lower end is supported on the base 102 side so as to be able to rotate. One end of the second arm 105b is supported on the base 102 side so as to be able to rotate.

Figure 4 shows a side view of the pantograph arm portion of the lifting device 100. Figure 4 corresponds to Figure 2, and in order to make the link mechanism easier to see, the first arm 105a and the second arm 105b at the front are omitted. The other end of the second arm 105b is held so that it can move parallel to the upper table 101 side. There is no particular limitation on the method of holding the other ends of the first arm 105a and the second arm 105b, but a well-known structure is, for example, one in which wheels are provided at the tips and rails are provided on the back side of the upper table 101 or on the top surface of the base 102.

A rotating shaft 115 is provided at the point where the first arm 105a and the second arm 105b intersect. The pantograph arm 105 opens and closes around this rotating shaft 115, and operates to raise and lower the upper table 101. This is a type known as a scissor jack.

A ball screw 106 and a nut 107 are provided between the first arm 105a and the second arm 105b, and one end of a multi-joint link 108 is connected to the nut 107. The other end of the multi-joint link 108 is connected to the first arm 105a. A braked motor 110 is provided at one end of the ball screw 106, and when the braked motor 110 rotates, the ball screw 106 rotates, and the nut 107 that screws into the ball screw 106 moves up and down along the ball screw 106. The braked motor 110 is energized by passing wiring through the wiring pit 30 shown in FIG. 1.

The nut 107 rises and falls in accordance with the forward and reverse rotation of the braked motor 110. In addition, the end of the ball screw 106 on the side where the braked motor 110 is provided is attached to a bar (not shown) that connects the lower ends of the pair of left and right second arms 105b. On the other hand, the other end of the ball screw 106 is not fixed.

Therefore, when the braked motor 110 rotates, the ball screw 106 rotates, causing the screwed nut 107 to rise and fall, and the pantograph arm 105 contracts via the multi-joint link 108, causing the upper table 101 to rise or fall. When the upper table 101 is at the lowest end, the folded lifting device 100 fits completely inside the pit 20, and the floor surface 10 and the upper table 101 form the same plane. The angle of the ball screw 106 changes with the angle of the second arm 105b.

One end of the bellows 120 is attached to the underside of the upper table 101. The other end of the bellows 120 is fixed to the bottom surface of the pit 20. The bellows 120 are flat, and multiple bellows 120 are attached to each side of the upper table 101 so as to surround the pantograph arm 105. They are structured to expand and contract as the upper table 101 rises and falls. There are no particular limitations on the material of the bellows 120, but since it is expected that it will be opened and closed repeatedly, it is preferable to use a fibrous material such as highly durable cloth.

Around the lifting device 100 configured as described above, a constriction prevention plate 130 is arranged. The constriction prevention plate 130 is erected along the inner wall surface of the pit 20. The constriction prevention plate 130 is made of a steel plate material, and the upper end is bent into an L-shape to form a top, and is arranged so that the lower surface of the upper table 101 abuts against the plate when the upper table 101 descends. The constriction prevention plate 130 is arranged without gaps on the inner circumference of the pit 20, but it is not prevented from being divided into multiple pieces and arranged. For example, it is conceivable to arrange four constriction prevention plates 130 on one side of the inner circumference of the pit 20. In addition, although the constriction prevention plate 130 is made of an L-shaped steel plate, it is not prevented from using punched metal or wire mesh-like members to reduce weight.

The tip of a gas-sprinkler type cylinder 135 is engaged with the underside of the top of the constriction prevention plate 130. At least two cylinders 135 are provided for the constriction prevention plate 130, allowing it to rise and fall. The cylinders 135 are fixed to the bottom surface of the pit 20, so that at the forward end of the cylinders 135, the constriction prevention plate 130 protrudes from the pit 20, and at the backward end of the cylinders 135, the constriction prevention plate 130 is completely contained inside the pit 20.

In this embodiment, the height of the constriction prevention plate 130 is set to protrude about 90 mm from the floor surface 10, and the depth of the pit 20 is set to a depth that allows the lifting device 100 to fit in the folded state, so that the constriction prevention plate 130 is at a height that allows it to fit fully inside the pit 20 when the cylinder 135 is at the retracted end. In addition, the constriction prevention plate 130 is held on the inner wall surface of the pit 20 by a guide (not shown). Therefore, the constriction prevention plate 130 is pushed down by the upper table 101 and fits inside the pit 20, and is pushed out by the cylinder 135 as the upper table 101 of the lifting device 100 rises.

The movable constriction prevention mechanism for a lifting device of this embodiment has the above-mentioned configuration, and therefore provides the following actions and effects.

First, one of the advantages is that it is possible to prevent any part of the body from getting stuck between the shallow pit 20 and the lifting device 100. This is because the movable constriction prevention mechanism for the lifting device, which corresponds to the lifting device 100 housed inside the pit 20 provided on the floor surface 10 of the factory, is equipped with a constriction prevention plate 130 that is arranged so as to be able to rise and fall along the inner wall surface of the pit 20, and a cylinder 135 that corresponds to a movable mechanism for raising and lowering the constriction prevention plate 130, and the height dimension of the constriction prevention plate 130 protruding from the floor surface 10 is lower than the height dimension of the lifting device 100 in the folded state when the upper table 101 of the lifting device 100 is at the lower end, and when the upper table 101 is at the lower end, the upper surface of the constriction prevention plate 130 is pressed by the lower surface of the upper table 101, so that the constriction prevention plate 130 is housed inside the pit 20, and when the upper table 101 is at the upper end, the constriction prevention plate 130 is pushed up by the cylinder 135 and rises to the upper end position.

Therefore, as the upper table 101 of the lifting device 100 rises, the constriction prevention plate 130 also rises, preventing any part of the body from getting stuck between the shallow pit and the lifting device. Figure 5 shows a side view of the lifting device 100 in a folded state. This constriction prevention plate 130 has the function of preventing the worker's toes from getting between the lifting device 100 and the edge of the pit 20.

As shown in the problem, without the constriction prevention plate 130, when the upper table 101 is lowered from the top end, it is possible that the upper table 101 may be pinched between the edge of the pit 20 and the pantograph arm 105, or between the edge of the pit 20 and the underside of the upper table 101. This is because workers tend to neglect to pay attention to their feet when working on a workpiece lifted up by the lifting device 100. However, as shown in this embodiment, by using the constriction prevention plate 130, even though it is only about 90 mm high, the constriction prevention plate 130 reliably prevents the toes from going over the edge of the pit 20.

As a result, it is possible to prevent the worker from unintentionally going beyond the edge of the pit 20. The area above the constriction prevention plate 130 is protected by the bellows 120, so it is possible to prevent part of the worker's body from accidentally going under the upper table 101. Furthermore, by using a relatively soft material for the bellows 120, it is possible to temporarily place part of the worker's body under the upper table 101 when necessary. Since the area within the worker's field of vision is likely to attract attention, the area covered by the bellows 120 is protected by the flexible bellows 120 so that it can be flexibly handled with consideration for workability, while the area around the feet, which is difficult to see, needs to be protected by a harder material. Therefore, by reliably protecting the edge of the pit 20 with the constriction prevention plate 130, a sufficient constriction prevention effect can be obtained.

When the upper table 101 of the lifting device 100 is raised, the constriction prevention plate 130 is pushed up by the gas spring cylinder 135 and protrudes, thus preventing constriction. On the other hand, when the upper table 101 is lowered, the plate is pushed by the underside of the upper table 101 and completely stored in the pit 20, as shown in FIG. 5. Therefore, when the lifting device 100 is not in use, no protrusions protrude from the floor surface 10, and they do not interfere with tasks such as moving workpieces onto the upper table 101.

The constriction prevention plate 130 does not require height, so the pit 20 only needs to be deep enough to accommodate the height of the lifting device 100 in its folded state, and even a shallow pit 20 can provide a movable constriction prevention mechanism for a lifting device that is highly effective at preventing constriction. Note that a gas spring type cylinder 135 is used to raise and lower the constriction prevention plate 130, but this does not prevent the use of a pneumatic or hydraulic cylinder. Also, this does not prevent the use of a motor-driven linear motion mechanism if necessary.

However, using a gas spring type that operates without the need for power is preferable as it is easy to install. Also, as the upper table 101 of the lifting device 100 rises, the force of the cylinder 135 causes the plate to rise automatically, so it is unlikely that the constriction prevention plate 130 will remain lowered due to an operator forgetting to operate it, ensuring safety. A sensor such as a limit switch may be provided for each constriction prevention plate 130 to check whether the plate has risen, thus ensuring safety. A system may also be provided to detect when the plate has not risen and to notify of an abnormality.

Although the movable constriction prevention mechanism for a lifting device according to the present invention has been described in detail above by showing an embodiment, the present invention is not limited to this, and various modifications are possible within the scope of the present invention. For example, an example of the lift-up structure of the lifting device 100 has been shown, but a table lift with a different structure can be used. As for the driving method, instead of the type using the ball screw 106 and the brake-equipped motor 110, a type using a hydraulic cylinder or a type using a bellows may be used. In addition, the height of the constriction prevention plate 130 is set to protrude 90 mm from the floor surface 10 when at the raised end, but it is sufficient to be high enough to prevent the worker's toes from entering the inside from the edge of the pit 20, and the height can be changed as necessary.

10 Floor surface 20 Pit 100 Lifting device 101 Upper table 130 Narrowing prevention plate 135 Cylinder

Claims (3)

A movable constriction prevention mechanism for a lifting device that is adapted to a lifting device that is housed inside a pit provided on a floor surface,
A constriction prevention plate is provided along the inner wall surface of the pit so as to be capable of rising and falling, and a movable mechanism for raising and lowering the constriction prevention plate,
The height dimension of the constriction prevention plate protruding from the floor surface is lower than the height dimension of the lifting device in a folded state when the upper table of the lifting device is at the lower end,
When the upper table is at the lower end, the upper surface of the constriction prevention plate is pressed by the lower surface of the upper table, so that the constriction prevention plate is contained inside the pit,
When the upper table is at the upper end, the constriction prevention plate is pushed up by the movable mechanism to rise to the upper end position;
The constriction prevention plate is disposed on the inner periphery of the pit without any gap;
When the constriction prevention plate protrudes from the floor surface, the lower end of the constriction prevention plate is located below the floor surface;
A movable constriction prevention mechanism for a lifting device, comprising: 2. The movable constriction prevention mechanism for a lifting device according to claim 1,
The constriction prevention plate is made of a hard material, and the movable mechanism uses a gas spring type cylinder.
A movable constriction prevention mechanism for a lifting device, comprising: A movable constriction prevention mechanism for a lifting device that is adapted to a lifting device that is housed inside a pit provided on a floor surface,
A constriction prevention plate is provided along the inner wall surface of the pit so as to be capable of rising and falling, and a movable mechanism for raising and lowering the constriction prevention plate,
The height dimension of the constriction prevention plate protruding from the floor surface is lower than the height dimension of the lifting device in a folded state when the upper table of the lifting device is at the lower end,
When the upper table is at the lower end, the upper surface of the constriction prevention plate is pressed by the lower surface of the upper table, so that the constriction prevention plate is contained inside the pit,
When the upper table is at the upper end, the constriction prevention plate is pushed up by the movable mechanism to rise to the upper end position;
The upper end of the bellows-type anti-constriction membrane is fixed to the lower surface of the upper table,
The anti-constriction membrane expands and contracts as the upper table rises and falls.
The anti-constriction membrane is made of a flexible material, and a worker can work by placing part of his/her body under the upper table.
The constriction prevention plate is made of a material harder than the constriction prevention film and protects the feet of the worker.
A movable constriction prevention mechanism for a lifting device, comprising:

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