JPH0893371A - Ladder - Google Patents

Abstract

PURPOSE: To make it possible to avoid danger that a hand may be clamped between horizontal sash bars by shortening the length of a support from an extended state and venting air prevailing in the support gradually and lowering an upper horizontal sash bar slowly. CONSTITUTION: When a ladder is shortened so as to house, an operation part of a lower most member 2a is pushed up and a locked second member 2b from the bottom is released so that it may fall down with the other locked member above the member 2b.Then, the volume of a post 4 is reduced so that the inside air may be vented gradually upward by way of cuts 41, thereby slowing down the falling speed. Then, a horizontal sash bar 6 of the second member 2a comes into contact with a horizontal sash bar 6 in the lower most part, which releases the locking of the third member 2c from the bottom and vents the air and lowers the member 2c and the upper member at a low speed. When the member 2b directly above the bottom by one step falls down, the horizontal sash bar 6 comes into contact with a stopper and comes to a halt, thereby preventing a hand from being clamped in between.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ladder, and more particularly to a retractable ladder.

[0002]

2. Description of the Related Art As a conventional expandable / contractible ladder, there is Japanese Patent Application No. 5-157911 proposed by the applicant of the present application.
As shown in FIG. 4 to FIG. 6, the schematic configuration thereof is a pair of support columns 4 and 4 which are arranged in parallel at a distance and have a hollow inside.
And a horizontal rail portion 6 provided between the upper ends of both of the columns.
Multiple members consisting of and (a number that is approximately equivalent to the number of ladder steps)
Are formed by sequentially changing the thicknesses of the support columns 4 and 4,
In both of the pillar portions of the thickest member 2a of the pillar portion,
Thin members 2b, 2c, 2d, ...
2n is slidably fitted from above so that the horizontal rail portion 6 of each member is brought into contact with each other in the vertical direction in a shortened state (the state shown in the lower half of FIG. 4), and The crosspiece 6 is formed so as to be in an extended state (a state shown in the upper half of FIG. 4) in which the crosspiece 6 is appropriately separated and the support post is fitted. The respective members are firmly coupled and formed so that the pair of support columns 4 and 4 and the horizontal cross-piece 6 are integrated. Then, as shown in FIGS. 5 and 6, the members other than the uppermost member 2n are provided in the horizontal rail portion 6 so as to project into the hollow portions of both of the column portions 4 and 4 by the biasing means 12. The projecting body 10 and the supporting holes 4 and 4 fitted in the hollow portion are formed of the engaging holes 8 with which the projecting body 10 projects and engages in the extended state to maintain the extended state. An engaging portion 11 and an operating portion 36 corresponding to the engaging portion 11 are provided so as to project downward from the horizontal rail portion 6, and the operating portion 36 is pushed up to release the protruding body 11. This is a configuration in which the means 14 is provided.

The projecting body 10 of the locking means 11 is a rod-shaped body, and is composed of a body portion 16, a neck portion 18, and an end portion 20.
The body portion 18 is slidably supported in the through hole 24 formed in the inner support wall 22, and the tip end 28 of the body portion 16 is formed of protective rubber. The urging means 12 projects into the support column 4 from a guide hole 26 formed in the guide 25. The biasing means 12 is the support wall 2
2 is a coil spring 31 arranged in a compressed state between the spring receiving washer 30 provided in the body portion 16. Unlocking means 1
Reference numeral 4 denotes a lever that rotates about the rotary shaft 32, one end 34 of which is engaged with the neck portion 18 of the projecting body 10 and the other end of which is an operating portion 36. Reference numeral 36 denotes a state in which the projecting body 10 projects and is fitted into the engaging hole 8, and projects downward from the lower edge of the horizontal cross-piece 6 as seen in FIG. When the operating portion 36 is pushed up to the lower edge 6a of the horizontal rail portion 6, as shown in FIG. 5, the projecting body 10 retracts and comes out of the engaging hole 8. In the lowermost member 2a, the support columns 4 and 4 are slightly extended downward, the lower end is provided with a non-slip rubber plug 37, and a reinforcing horizontal bar 38 is provided.

In the shortened state, this ladder is in a state in which the horizontal rail portions 6, 6, ... Are in contact with each other vertically as seen in the lower half of FIG. Further, in the extended state, as shown in the upper half of the figure, the cross rails 6, 6, ... Form the steps of the ladder apart from each other, and as shown in FIG. The projecting body 10 is projectingly engaged with the engaging hole 8 and the operating portion 32 of the locking releasing means 14 is projecting below the horizontal rail portion 6. To change from the extended state to the shortened state, the operating portion 36 of the locking releasing means 14 projecting downward from the horizontal rail portion 6 of the member 2a is pushed up, and the locking of the support columns 4 and 4 of the member 2b is released. Therefore, the member 2b descends due to the weight of the member itself and the members above it, and the supporting columns 4 and 4 of the member 2b are deeply fitted into the supporting columns 4 and 4 of the member 2a so that the respective horizontal crossbars 6 and 6 are formed. It comes into contact. At this time, since the operating portion 36 of the unlocking means 14 of the member 2b is relatively pushed up by the cross rail portion 6 of the member 2a, the locking of the member 2c thereon is further released, and the member 2c and itself are lifted. The member 2 d is lowered by the weight of the member, and thereby the locking of the member 2 d is released. In this way, the locked state is sequentially released from the lower one to the upper one, and the shortened state is brought about by its own weight.

[0005]

In this way, the retractable ladder is in a state in which the human hand is positioned above the horizontal cross section 6 of the lowermost member 2a when the lock is released in the extended state. If, for example, the horizontal rail portion 6 and the lever of the unlocking means 14 are simultaneously operated, there is a risk of being injured by being pinched by the horizontal rail portion 6 of the descending upper member. It is an object of the present invention to provide a ladder that can avoid such a danger.

[0006]

According to a first aspect of the present invention, in an expandable ladder as described above, the exhaust resistance is such that the air in the support column is gradually exhausted when the extension state is shortened. Means are provided. The exhaust resistance means closes the lower part of the inner hole of the member located at the lowermost part of the plurality of members, and provides at least one of the other members with a partition wall that vertically divides the hollow part of the column. A ladder characterized in that the partition is provided with a ventilation part. The exhaust resistance means closes the lower end of the hollow portion of the column portion of the lowermost member, and provides a partition wall for partitioning the hollow portion of the column portion into at least one of the members other than the lowermost portion. It is preferable that the partition wall be provided with a ventilation part. The ventilation part is preferably a small hole. Separately, it is preferable that the partition wall is formed of a plate-shaped material having elasticity, and the ventilation portion is formed by a cut provided so as to penetrate the plate-shaped material.

In a second aspect of the present invention, in the above-described expandable / contractible ladder, a horizontal rail portion of the lowermost member is provided so as to project upward, and abutting against the upper horizontal rail portion in the shortened state, It is characterized in that a stopper is provided between the parts to form a gap into which a hand can be inserted with a margin. In the second aspect of the invention, it is preferable that the stopper is provided at a position of the upper horizontal rail portion facing the operation portion.

[0008]

The means of the first invention utilizes the fact that the volume inside the strut decreases when the strut is changed from the extended state to the shortened state, and the internal air existing in the stretched state is gradually exhausted during the shortening process. By doing so, the speed of the descending member decreases. As a result, it is possible to avoid the risk of a hand being caught between the horizontal rails. The configuration in which the partition wall and the ventilation portion are provided in at least one member other than the lowermost member, for example, when provided in the uppermost member, the exhaust resistance acts from the beginning to the end between the extended state and the shortened state. However, if it is provided only on the uppermost one member at the bottom, the exhaust resistance acts only until the member descends. This exhaust resistance acts to reduce the descending speed of the member. Of course, the partition wall and the ventilation portion may be provided in a member in the middle other than the uppermost member or the uppermost one member. In that case, for example, the partition member and the ventilation member may be provided in the middle member and the uppermost member. When provided, both the ventilation part of the member and the ventilation part of the uppermost part slow down the descending speed until the intermediate member reaches the lowered position, and thereafter the ventilation of the uppermost part. Only the part will slow down. Note that this configuration is a configuration in which the lower end is closed and exhaust is performed upward, and conversely, it is conceivable that the upper end is closed or midway closed to exhaust downward, but normally, a rubber stopper to prevent slippage is attached to the lower end. Since it is mounted, the lower end is closed without providing a closing member. Therefore, it is more convenient to exhaust the gas upward when the lower end is closed. If the vent is a small hole,
It has a simple structure and excellent durability.

According to the second aspect of the invention, when the uppermost member on the lowermost part comes down, the cross rail portion thereof comes into contact with the stopper and stops, so that the hand is not caught. Further, in the configuration in which the stopper faces the operating portion of the upper horizontal rail portion, when the stopper abuts the horizontal rail portion, the operating portion of the upper member is further pushed up, so that the state is shortened by the same operation as the conventional one. Becomes

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIG. This embodiment corresponds to the first invention, and is the one in which the exhaust resistance means 40 is provided on the conventional ladder described previously with reference to FIGS. 4 to 6. Except for the exhaust resistance means 40, since it is the same as the conventional ladder, only the exhaust resistance means 40 will be described, and the equivalent parts are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 1 (a), the exhaust resistance means 40 is provided at the lower ends of the support columns 4 on both sides of the second and third members 2b, 2c from the bottom as shown in FIG. 1 (b). A partition 42 made of a rubber plate having a cross-shaped cut 41 as a ventilation part is fixedly provided. The break 41 penetrates the partition wall 42 vertically. Reference numeral 43 in FIG. 1A is a synthetic resin ring-shaped member, which is the same as that normally provided as a sliding portion for the inner hole,
An annular groove is provided near the lower end of each of the outer circumferences of the pillars that are sequentially fitted into the inner holes of the pillars 4. Further, although not seen in the figure, the upper end of the column part 4 of the uppermost member is in an open state in which air can freely flow in and out, and the lower end of the column part 4 of the lowermost member is covered with a non-slip rubber stopper to prevent air from entering. It is in a closed state where you cannot enter or leave.

The ladder thus constructed is used in a stretched state when used, as in the conventional case, and is shortened when stored. When in the shortened state, the operation portion 3 of the lowermost member 2a
When 6 is pushed up, the second member 2b from the bottom is unlocked, and the member 2b and the member above it in the locked state descend together. Since the volume inside the support column is reduced by the lowering, the internal air is pushed out upward. However, the descending speed is not so rapid as to fall naturally, and
It is slow because the air in the inside is gradually discharged upward through the cuts 41, 41 which are ventilation parts. Therefore, it is possible to prevent the hand from being caught by the descending cross rail. When the horizontal rail portion 6 of the second member 2a contacts the lowermost horizontal rail portion 6, the locking of the third member 2c from the bottom is released. As a result, air is exhausted through the ventilation portion of the member 2c, and the member 2c and the member above it descend at a low speed. Then, when the horizontal rail portion 6 of the member 2c comes into contact with the horizontal rail portion 6 of the member 2b, the locking of the member 2c is released, and thereafter, since there is no exhaust gas resistance means, the members rapidly descend sequentially.

FIG. 3 (c) shows another embodiment of the first invention, in which the exhaust resistance means 40 is a partition wall 45 made of a metal plate having a small hole 44 formed therein. Set up.
Since the small hole 43 limits the outflow amount of air, it has substantially the same operation as the cut 41, and the operation when it is in the shortened state is also the same, and therefore its explanation is omitted.

A second embodiment of the present invention will be described with reference to FIGS. This embodiment corresponds to the second invention,
A stopper 50 is provided on the conventional ladder described above with reference to FIGS. 4 to 6. Except for the stopper 50,
Since it is the same as the conventional ladder, only the stopper 50 will be described, and the same parts will be denoted by the same reference numerals and the description thereof will be omitted. The stoppers 50 are provided so as to project upward on the respective horizontal rail portions 6 of the lowermost member 2a and the second member 2b from the bottom, and the protruding height thereof is lower than that of the upper horizontal rail portion 6 in the shortened state. The height is such that it abuts against the edge 6a and forms a gap e between the horizontal rails so that a human hand H can be inserted with a margin. The protruding position of the stopper 50 is near both ends of the horizontal rail portion 6,
It is a position facing the operation unit 36 from below.

The ladder thus constructed is used in a stretched state when used, as in the conventional case, and is shortened when stored. When in the shortened state, the operation portion 3 of the lowermost member 2a
When 6 is pushed up, the second member 2b from the bottom is unlocked, and the member 2b and the members 2c, ... The descending speed is a speed close to a natural fall, but the lower edge 6a of the member 2b comes into contact with the protruding end of the stopper 50 and stops. Therefore, since the gap e is formed, even if the hand is positioned above the horizontal rail 6 of the lowermost member 2a, it is not pinched and injured. When the second member 2b from the bottom is lowered and stopped by the stopper 50,
Since the operating portion 36 of the member 2b is pushed up by the stopper 50, the locking of the upper member 2c is released. As a result, the member 2c descends as described above and stops at the stopper 50. At this time, the locking of the member 2d is released, and subsequently the member 2d and the member above it are lowered.
After that, since there is no stopper 50, the member is in a shortened state like the conventional ladder with which the cross rails of the members abut. The stopper 50 is also provided on the member 2b for the sake of safety.

In the first embodiment, the stopper shown in the second embodiment may be used together. Further, an elastic material, for example, an interference material made of a soft synthetic resin, rubber or the like may be provided on the upper end of the stopper 50 of the second embodiment. Further, the stopper 50 of the second embodiment is shown as being integrally formed with the horizontal rail portion 6, but in some cases, instead of this, a bolt may be attached so as to project upward.

[0017]

According to the first aspect of the present invention, when the strut is shortened from the stretched state, the air inside the strut is gradually exhausted during the shortening process, so that the descending speed of the upper crosspiece becomes slower. It is possible to avoid the risk of getting your hands caught between the cross rail and the cross rail. In the second invention, when the uppermost member at the lowermost part comes down, the cross rail portion comes into contact with the stopper and stops, so that the hand is not caught.

[Brief description of drawings]

FIG. 1 (a) is a vertical sectional side view showing a main part of a first embodiment of the present invention, and FIG. 1 (b) is an enlarged perspective view of a partition wall provided with a cut.
(C) is an enlarged perspective view of a partition wall provided with small holes of another embodiment.

FIG. 2 is an enlarged front view of a longitudinal section showing a main part of a second embodiment of the present invention in a shortened state.

FIG. 3 is a partially omitted front view of the same embodiment.

FIG. 4 is a partially omitted front view of a conventional telescopic ladder.

FIG. 5 is an enlarged vertical cross-sectional front view of a main portion showing a conventional unlocked state of the ladder.

FIG. 6 is an enlarged vertical sectional front view of a main portion showing a locked state of the conventional ladder.

[Explanation of symbols]

 2a member (bottom) 2b member (second from bottom) 2c member (third from bottom) 2n member (top) 4 strut part 6 lateral beam part 8 engaging hole 10 projecting body 11 locking means 12 biasing means 14 Lock Release Means (Lever) 32 Rotating Shaft 36 Operating Section 40 Exhaust Resistance Means

Claims (6)

[Claims] 1. A plurality of members, each of which is composed of a pair of pillars, which are arranged in parallel at a distance from each other and are hollow inside, and a horizontal crosspiece provided between the upper ends of both of the pillars, are sequentially arranged. The columns are formed with different thicknesses, and the two columns of the thickest member of the columns are sequentially slidably fitted with the thin members of the columns, and the horizontal cross section of each member is The horizontal rails of each member are formed so as to be in a shortened state and the horizontal rail portions of the members are appropriately separated to be in an extended state in which the support columns are fitted. Inside the crosspiece, there is a locking means for holding the extended state, and an operation part corresponding to the locking means and projecting downward from the horizontal crosspiece, and the locking is released by pushing up the operation part. In the ladder provided with the unlocking means, when the extension state is shortened A ladder, wherein exhaust resistance means is provided so that the air in the column is gradually exhausted. 2. The ladder according to claim 1, wherein the exhaust resistance means closes a lower portion of an inner hole of a member located at a lowermost portion of the plurality of members, and at least one of the other members has a column portion thereof. A ladder in which a partition is provided to divide the hollow part of the partition into upper and lower parts, and a ventilation part is provided in the partition. 3. The ladder according to claim 2, wherein the ventilation part is a small hole. 4. The ladder according to claim 2, wherein the partition wall is formed of a plate-shaped material having elasticity, and the ventilation part is formed by a cut provided so as to penetrate the plate-shaped material. Ladder characterized by. 5. A plurality of members, each of which is composed of a pair of support columns which are arranged in parallel at a distance from each other and have a hollow inside, and a horizontal cross section which is provided between the upper ends of both the support columns, are sequentially provided. The columns are formed with different thicknesses, and the two columns of the thickest member of the columns are sequentially slidably fitted with the thin members of the columns, and the horizontal cross section of each member is The horizontal rails of each member are formed so as to be in a shortened state and the horizontal rail portions of the members are appropriately separated to be in an extended state in which the support columns are fitted. Inside the crosspiece, there is a locking means for holding the extended state, and an operation part corresponding to the locking means and projecting downward from the horizontal crosspiece, and the locking is released by pushing up the operation part. In a ladder provided with an unlocking means, the ladder is directed upwards to the cross rail of the lowermost member. A ladder which is provided so as to project, and which is provided with a stopper that abuts an upper horizontal rail portion in the shortened state and forms a gap between the horizontal rail portions so that a hand can be inserted with a margin. 6. The ladder according to claim 5, wherein the stopper is provided at a position of the upper horizontal rail portion facing the operation portion.