JP5433915B2 - Stepladder fall prevention device - Google Patents

Description

  The present invention relates to a stepladder fall prevention device.

As is well known, a stepladder is used in a state where a pair of ladders provided with a plurality of steps between left and right legs are fixed in a state of being opened in a square shape.
Here, if the worker on the stepladder loses balance, the stepladder may fall in the left-right direction (FIG. 8). For this reason, conventionally, there has been proposed a stepladder attached with a fall prevention tool for preventing the fall (see Patent Documents 1 and 2).

JP-A-9-49383 (abstract) Design registration No. 10032182

The fall prevention device of Patent Document 1 is provided with triangular plate-like auxiliary legs projecting outside the left and right leg portions provided with ladder ladders.
However, in order to sufficiently prevent the fall, it is necessary to make the auxiliary leg large and thick, and the stepladder becomes heavy.

On the other hand, the overturn prevention tool of Patent Document 2 includes auxiliary legs that are freely opened and closed on the legs of the stepladder. The auxiliary legs are opened by engaging with racks fixed to the legs.
However, in order to open the auxiliary leg to an opening that can sufficiently prevent the stepladder from falling, it is necessary to provide a long rack, and it is difficult to reduce the weight.
Furthermore, it is conceivable to provide a one-way clutch on the leg to adjust the opening of the auxiliary leg. However, when a one-way clutch is used, backlash may occur and stability may be impaired.

  Accordingly, an object of the present invention is to provide a simple and lightweight stepping prevention tool for a stepladder.

  In order to achieve the above-described object, the stepladder fall prevention device of the present invention includes an elongated fixed frame fixed along the leg portion of the stepladder, and an upper end position and a lower end position along the surface of the fixed frame. A taper-shaped contact that is provided so as to be reciprocally movable up and down, and that approaches the leg portion of the stepladder as it is provided on the opposite side of the first surface and on the opposite side of the first surface. A wedge part having a contact surface; guide means for guiding the wedge part to move up and down; urging means for applying a downward movement force to the wedge part; and rotation with respect to the fixed frame A long rotating leg that can rotate in an opening direction downward and a closing direction upward from the center, and the rotation leg that can rotate relative to the fixed frame around the rotation center. A supporting shaft part, and a projection projecting radially from the shaft part to the front of the rotating leg. By turning in the opening direction, the lower end of the wedge portion at the lower end position of the fixed frame is pushed up to move the wedge portion upward against the biasing means, and the wedge portion is moved By contacting the contact surface of the wedge portion that moves downward by the urging means after being pushed up, the rotating leg is prevented from rotating in the closing direction, and the stepladder is prevented from falling over. A contact member.

According to the present invention, in a state where the contact member is in contact with the tapered contact surface of the wedge portion, the rotating leg is directed upward with respect to the fixed frame, that is, in the closing direction in which the rotating leg is closed. Therefore, no backlash occurs between the contact surface and the contact member.
Moreover, since it is not necessary to form a long rack, the fall prevention tool can be reduced in weight.
Furthermore, unlike using a commercially available one-way clutch, the manufacturing cost is also reduced.
In addition, since the fall prevention tool can be retrofitted to a commercially available stepladder, safety can be easily improved by requiring a person who comes in and out of the site to attach the fall prevention tool.

It is a schematic sectional drawing which shows the usage method of the fall prevention tool of the stepladder concerning one Example of this invention. It is a schematic sectional drawing which shows the usage method of the fall prevention tool. It is a schematic sectional drawing which shows the usage method of the fall prevention tool. It is a schematic sectional drawing which shows the usage method of the fall prevention tool. 5A is a schematic plan sectional view of the overturn prevention device, FIG. 5B is a sectional view taken along the line VB-VB in FIG. 5A, and FIG. 5C is a sectional view taken along the line VC-VC in FIG. It is a schematic side view which shows the open state of a rotation leg. It is a schematic side view which shows the accommodation state of a rotation leg. It is a schematic side view which shows the stepladder to which the fall prevention tool of the accommodation state was attached. It is a schematic side view which shows the stepladder of the state which opened the rotation leg and used the fall prevention tool.

In a preferred aspect of the present invention, the apparatus further includes a rod fixed to the upper end of the wedge part, and an operation part protruding from the fixed frame and lifting the wedge part together with the rod to the upper end position.
According to this aspect, the wedge part can be easily lifted to the upper end position by operating the operation part protruding from the fixed frame. In this state, the rotating leg can be rotated and stored in the closing direction.

In a preferred aspect of the present invention, there is further provided holding means for holding the rod or the operating portion so that the wedge portion does not move at the upper end position.
According to this aspect, it is possible to maintain a state in which the wedge portion does not move at the upper end position. This facilitates the movement of the rotating leg in the closing direction.

In a preferred aspect of the present invention, a release means for releasing the holding by the holding means when the transverse cross section of the fixed frame is formed in a substantially concave shape and the rotating leg is folded in the concave fixed frame. In addition.
According to this aspect, since the holding is released when the pivot leg is folded, the push-up operation is reliably performed while the pivot leg is pivoted in the opening direction, and the abutting member touches after the push-up. Contact the contact surface. Therefore, it is possible to prevent a situation in which the contact member is not in contact with the contact surface in spite of the rotating leg being open in the use state.

In a preferred aspect of the present invention, in a use state in which the abutting member abuts against the abutting surface of the wedge portion and the rotating leg is prevented from rotating in the closing direction, Further, a self-weight rotation preventing means for preventing the rotation leg from rotating in the opening direction is further provided.
Here, in the state of use, when the rotating leg is opened by its own weight in the opening direction, the lower end of the rotating leg is grounded without the lower end of the stepladder being grounded, and the weight of the operator is loaded on the fall prevention device. Things will happen. On the other hand, in this aspect, since the self-weight rotation prevention means is provided, the rotating leg does not open in the opening direction with its own weight in the use state, and thus the above-described situation can be prevented.

Stepladder A:
The stepladder A shown in FIG. 8 includes four leg portions AL, and a plurality of steps A1 are spanned between the pair of leg portions AL. When in use, the pair of legs AL around which the foot A1 is stretched are opened at a predetermined angle.

Fall prevention tool B:
In the pair of legs AL, a fall prevention tool B is attached to the outer side surface of the foot A1 in the left-right direction X by a bolt / nut or a bracket (not shown).
As shown in FIG. 7, the fall prevention tool B includes a long fixed frame 1 that is fixed along the leg portion AL of the stepladder A, an open direction Ro that extends downward about the rotation center O, and , And a long rotating leg 5 that is rotatable in the upward closing direction Rs shown in FIG.
9 may be attached to each of the pair of leg portions AL on one side, or may be attached to all of the four leg portions AL.

  When the stepladder A is used, the rotating leg 5 is opened in the opening direction Ro as shown by an arrow in FIG. 8, and its end is grounded to a grounding surface such as the ground as shown in FIG. Used in a fixed state. On the other hand, when the rotating leg 5 is stored, the rotating leg 5 is rotated in the closing direction Rs and stored as shown in FIG.

Fixed frame 1:
As shown in FIGS. 5B and 5C, the fixed frame 1 is formed in a U-shaped cross section having a fixed surface 1a fixed to the leg portion AL.
As shown in FIG. 1A, a plate-like sliding guide 1 c is fixed in the fixed frame 1.

Wedge part 2:
A wedge portion 2 made of a slider is provided in the fixed frame 1. The wedge portion 2 includes a first surface 20f that contacts the surface 1f of the sliding guide 1c, and a contact surface 20 provided on the opposite side of the contact surface 20. The wedge portion 2 is provided such that the first surface 20f of the wedge portion 2 is slidable in the vertical direction Z along the surface 1f of the sliding guide 1c.
The wedge portion 2 is provided so as to reciprocate in the vertical direction Z between a lower end position Pd shown in FIG. 1A and an upper end position Pu shown in FIG. 4A.

  The contact surface 20 is formed in a tapered shape that approaches the leg portion AL of the stepladder A as it goes downward Z1.

Rod 30:
A rod 30 is fixed to the upper end of the wedge portion 2. The fixed frame 1 is provided with two guide means 3 in the vertical direction for holding the rod 30 slidably in the vertical direction Z. The guide means 3 is formed around the rod 30 and guides the movement of the rod 30 in the vertical direction Z.

  The rod 30 is provided with an operation unit 31. As shown in FIG. 6, the operation portion 31 is provided so as to protrude from the fixed frame 1. As shown in FIG. 4A, the contact surface 20 at the lower end position Pd in FIG. 3B is raised to the upper end position Pu by lifting the rod 30 upward Z2.

  1A between the operation portion 31 and the upper guide means 3 shown in FIG. 1A is a first spring (a biasing means) that applies a force to move the contact surface 20 downward Z1 via the guide means 3. An example) 4 is provided. The first spring 4 is wound around the rod 30.

Rotating leg 5:
A fixed shaft 1 b having the rotation center O is fixed to the fixed frame 1. The pivot leg 5 is integrally provided with a shaft portion 50 that pivotally supports the pivot leg 5 with respect to the fixed frame 1 around the pivot center O. The shaft portion 50 is rotatably supported on the fixed shaft 1b.
As shown in FIGS. 1A to 4B, the rotating leg 5 is a long length that can rotate with respect to the fixed frame 1 in the opening direction Ro toward the lower Z1 and the closing direction Rs toward the upper Z2 around the rotation center O. It is formed in a shape.

Contact member 51:
A contact member 51 protrudes and is formed integrally with the shaft portion 50 at the distal end portion of the rotating leg 5 shown in FIG. 1A on the fixed shaft 1b side. The abutting member 51 protrudes from the shaft portion 50 in the radial direction (of the shaft portion 50) and is fixed to the rotating leg 5 at a predetermined angle.

  The angle formed by the long rotating leg 5 and the contact member 51 is an angle at which the wedge part 2 can be raised as shown in FIGS. 1B and 2A when the rotating leg 5 is opened. Is set to On the other hand, as shown in FIGS. 2B to 3B, the shaft portion 50 is set to a length capable of moving on the contact surface 20 of the descending wedge portion 2.

Here, as shown in FIGS. 2B to 3B, when the contact member 51 is moving on the contact surface 20, the contact surface 20 is lowered by the extension of the first spring 4, and the contact member 51. Is in contact with the contact surface 20. For this reason, the rotating leg 5 rotates in the opening direction Ro, but if the rotating leg 5 tries to rotate in the closing direction Rs, the tip of the contact member 51 comes into contact with the contact surface 20 and closes in the closing direction Rs. The rotation of the rotating leg 5 in the direction is restricted.
Therefore, the abutting member 51 abuts on the abutting surface 20, so that the rotating leg 5 can be fixed at an arbitrary angle steplessly in the closing direction Rs.

Holding means 6:
As shown in FIG. 1A, a constricted portion 61 is formed at the upper end portion of the rod 30. On the other hand, as shown in FIGS. 5A and 5B, the fixed frame 1 is provided with a pair of holding members 60 that sandwich and hold both side surfaces of the constricted portion 61.
When the rod 30 is pushed up to the upper end position Pu shown in FIG. 5A by the operating portion 31, both side surfaces of the constricted portion 61 on the upper portion of the rod 30 are sandwiched between the holding members 60, and the rod 30 is Held in position.
Therefore, the holding member 60 and the constricted portion 61 constitute a holding means 6 that holds the wedge portion 2 at the upper end position Pu.

Release means 7:
As shown in FIG. 5B, the cross section of the fixed frame 1 is formed in a generally concave shape.
The holding member 60 is integrally formed with release means 7 for spreading the pair of holding members 60 together. The release means 7 is for releasing the engagement between the holding member 60 and the constricted portion 61.
As shown in FIG. 1A, when the rotating leg 5 is rotated and folded into the concave-shaped rotating leg 5, both release plates 7 (FIG. 5B) are moved by the side surface of the rotating leg 5 in FIG. 1A. It is pushed out. Since the holding member 60 is formed integrally with the release plate 7, the distance between the holding members 60 is widened, the engagement between the holding member 60 and the constricted portion 61 is released, and the rod 30 is moved to the lower end position by the biasing means 4. Descend to

Self-weight rotation prevention means:
As shown in FIGS. 2B and 3A, a second spring 8 is provided on the fixed shaft 1b. As shown in FIG. 5C, the second spring 8 is engaged with the fixed frame 1 and the contact member 51. Therefore, as shown in FIG. 2B and FIG. 3A, after the rotating leg 5 is fixed at an arbitrary angle, the rotating leg with respect to the fixed frame 1 by the spring force biased by the second spring 8 even if the stepladder A is lifted. The angle of 5 is fixed. Therefore, even if the stepladder A is moved, the angle between the fixed frame 1 and the rotating leg 5 does not change due to the weight of the rotating leg 5.
Therefore, the second spring 8 constitutes its own weight rotation preventing means.

As shown in FIG. 1B, the release means 7 is formed with a convex portion 7a that engages with the concave portion 5a (FIG. 6) of the rotary leg 5. In the retracted state shown in FIG. The leg 5 is set so as not to open carelessly.
Further, as shown in FIG. 6, the tip of the rotating leg 5 is provided with a non-slip 5 b for preventing the tip of the rotating leg 5 from slipping when it contacts the grounding surface such as the ground. Yes. The slip stopper 5b is made of rubber or the like, for example.

How to use the fall prevention tool:
As shown in FIG. 8, the rotating leg 5 is located in the storage state.
First, the leg part AL of the stepladder A is opened to stand the stepladder A. Thereafter, a portion (lever part) 5c protruding from the fixed frame 1 of the rotating leg 5 shown in FIG. 7 is held, and the rotating leg 5 is opened in the opening direction Ro.

Here, as shown in FIG. 1A, the rod 30 and the wedge portion 2 are located at a lower end position Pd that is lowered downward Z1 in the housed state. When the pivot leg 5 is pivoted in the opening direction Ro from the stored state, the abutment member 51 pivots around the point O together with the pivot leg 5 and eventually abuts as shown in FIG. 1B. The front end portion of the member 51 abuts on the lower end 21 of the wedge portion 2.
Further, when the pivot leg 5 is pivoted in the opening direction Ro, the tip portion of the contact member 51 pushes up the lower end 21 of the wedge portion 2 as shown in FIG. 2A. When the wedge part 2 is pushed up, the rod 30 is moved upward Z2 and the first spring 4 is contracted.

  When the pivot leg 5 is opened beyond a predetermined angle and the first contact limit of FIG. 2B is passed, the tip portion of the contact member 51 rides on the contact surface 20 of the wedge portion 2 and starts to contact.

Furthermore, as shown in FIGS. 3A to 3B, when the rotating leg 5 rotates and contacts the grounding surface such as the ground while the rotating leg 5 opens to the contact limit, as described below, the rotating leg 5 rotates. The moving leg 5 is fixed at the angle.
Here, when the pivot leg 5 of FIG. 3A is opened larger than the first contact limit, the first spring 4 begins to expand, and the contact surface 20 is urged downward Z1 by the first spring 4. The Therefore, even if the rotating leg 5 tries to rotate in the closing direction Rs, the wedge portion 2 enters between the tip of the contact member 51 and the surface 1f, and the rotating leg 5 is in the closing direction Rs direction. Does not rotate.

That is, when the contact member 51 contacts the contact surface 20 of the wedge portion 2 to move downward Z1 by the spring 4, the rotation leg 5 is prevented from rotating in the closing direction Rs.
Therefore, as shown in FIG. 9, by supporting the stepladder A in the left-right direction X by the rotating leg 5, it is possible to prevent the stepladder A from falling in the left-right direction X.
In such a use state, the worker climbs the stepladder A to perform work.

3A is biased in the closing direction Rs by the second spring 8, there is no possibility that the rotating leg 5 rotates in the opening direction Ro under its own weight.
That is, in the use state in which the abutting member 51 abuts against the abutting surface 20 of the wedge portion 2 and prevents the rotating leg 5 from rotating in the closing direction Rs by the above-described self-weight rotation preventing means. The rotating leg 5 is prevented from rotating in the opening direction Ro by its own weight.
In general, it is preferable that the angle formed between the pivot leg 5 and the ground contact surface with which the pivot leg 5 contacts is set to approximately 45 °.
Further, the rotating leg 5 can be opened to the second contact limit shown in FIG. 3B.

  In order to rotate and fold the rotating leg 5 in the closing direction Rs, first, as shown in FIG. 4A, the operator pulls up the operation unit 31 (FIG. 6) to the upper Z2. By pulling up the operating portion 31 upward Z2, the constricted portion 61 of the rod 30 is engaged with the holding member 60. Therefore, the contact surface 20 is held at the upper end position Pu (and stopped), and the rotating leg 5 can be rotated in the closing direction Rs.

As shown in FIG. 4B, when the turning leg 5 is turned in the closing direction Rs and the turning leg 5 is turned to the storage state shown in FIG. 1A, both side surfaces of the turning leg 5 are shown in FIG. 5B. The pair of release means 7 shown is pushed open. When the pair of release means 7 are moved outward from each other, the pair of holding members 60 are moved away from each other, the constricted portion 61 shown in FIG. 5A is detached from the retaining member 60, and the constricted portions 61 are engaged. Canceled.
When the engagement of the constricted portion 61 is released, the wedge portion 2 is lowered from the upper end position Pu to the lower end position Pd shown in FIG. 1A by the spring force of the spring 4.
On the other hand, the recess 5a shown in FIG. 6 engages with the protrusion 7a shown in FIG.

  The stepladder fall prevention tool of the present invention can be used to prevent the stepladder from falling.

1: Fixed frame 1f: Surface 2: Wedge part 3: Guide means 4: Biasing means 5: Rotating leg 6: Holding means 7: Release means 20: Abutting surface 21: Lower end 30: Rod 31: Operation part 50: Shaft 51: Contact member A: Stepladder A
AL: Leg O: Center of rotation Pu: Upper end position Pd: Lower end position Ro: Open direction Rs: Close direction

Claims (5)

A long fixed frame fixed along the legs of the stepladder;
A reciprocating motion is provided between the upper end position and the lower end position along the surface of the fixed frame. The first surface is in contact with the surface of the fixed frame, and the lower surface is provided on the opposite side of the first surface. A wedge part having a tapered contact surface approaching the leg part of the stepladder as it goes,
Guiding means for guiding the wedge portion moving up and down;
An urging means for applying a downward movement force to the wedge part;
A long rotating leg that can rotate in an opening direction downward and a closing direction upward with respect to the rotation center with respect to the fixed frame;
A shaft portion that rotatably supports the rotating leg with respect to the fixed frame around the rotation center;
The wedge portion protrudes radially from the shaft portion and pivots the pivot leg in the opening direction, thereby pushing up the lower end of the wedge portion at the lower end position of the fixed frame to resist the biasing means. The pivot leg pivots in the closing direction by moving it upward and abutting against the abutment surface of the wedge section that moves downward by the biasing means after the wedge section is pushed up. A contact member that prevents the stepladder from overturning, and
A stepladder prevention device with a stepladder. In Claim 1, the rod fixed to the upper end of the wedge part;
A stepladder fall prevention device further comprising an operation portion protruding from the fixed frame and lifting the wedge portion together with the rod to the upper end position above.   The stepladder fall prevention device according to claim 2, further comprising holding means for holding the rod or the operating portion so that the wedge portion does not move at the upper end position.   4. The release frame according to claim 3, further comprising release means for releasing the holding by the holding means when the transverse cross section of the fixed frame is formed in a generally concave shape, and the rotating leg is folded into the fixed frame having the concave shape. A step-up prevention tool for stepladders.   2. The use state according to claim 1, wherein the abutting member abuts against the abutting surface of the wedge portion to prevent the pivoting leg from pivoting in the closing direction. A stepladder overturn prevention device further comprising a self-weight rotation prevention means for preventing the rotation leg from rotating in the opening direction.

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