JPH0520878Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a telescoping ladder that has a plurality of ladder members and is expanded and contracted by relative movement of these ladder members.

[Conventional technology]

2. Description of the Related Art Telescoping ladders have conventionally been used for high-altitude work at construction sites and the like. This telescoping ladder is extended during work to facilitate work at high places, and is retracted at the end of the work to facilitate transport and save space during storage.

In conventional examples of such telescoping ladders, a plurality of ladder members are housed in a nested manner, traction means such as pulleys are attached to these ladder members, a rope or wire is passed through the pulleys, and the rope is used for work. The ladder is extended by being pulled directly by a person's hand or indirectly by a winch, or the ladder is extended by automatically pulling the wire by means such as a motor. be.

[Problem that the invention attempts to solve]

However, according to the above-mentioned conventional example, when the rope or wire is pulled by the worker's hands, whether the rope or wire is pulled directly or indirectly by a winch, it takes a lot of work to extend the ladder. It requires a lot of effort from the staff. In particular, the greater the length of the ladder, the greater the effort required. Furthermore, if a motor or the like is used to pull the wire, there is a problem in that the device must become larger and more complicated.

An object of the present invention is to provide a telescoping ladder with a simple structure that can be extended without any effort.

[Means for solving problems]

The present invention attempts to use a spring to extend a ladder, which conventionally had to be done by a worker's hand. Its specific configuration is the ladder main body, the traction member,
The ladder main body has a plurality of ladder members and can be expanded and contracted by relative movement of these ladder members, and the traction member is pulled to one side between the plurality of ladder members. and the ladder body is connected to extend and contract when pulled to the other side, the extension means having a spring that biases the traction member to extend the ladder body, and the locking means is configured to be able to prevent relative movement of the ladder member in the direction of contraction.

[Effect]

Accordingly, the present invention allows the ladder member to be relatively moved so that the ladder main body is extended via the traction member by the biasing force of the spring of the extension means while the relative movement of the ladder member in the direction of contraction is prevented by the locking means.
The ladder body is prevented from contracting even if a worker climbs the ladder while the ladder body is extended, and the locking means allows relative movement of the ladder member in the direction of contraction to resist the biasing force of the spring. This aims to achieve the above objective by shrinking the ladder body.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 11. Here, in each embodiment, the same or equivalent constituent parts are given the same reference numerals, and the explanation will be omitted or simplified.

1 to 7 show a first embodiment of the present invention. The first embodiment is an example applied to a double ladder.

FIG. 1 shows the front of the telescoping ladder, that is, the state in which the telescoping ladder is propped up. In this FIG. 1, the telescoping ladder includes a ladder body 10 made of titanium, and this ladder body 10 has a first
Consisting of a ladder member 11 and a second ladder member 12 nested in the first ladder member 11,
By relatively moving the first and second ladder members 11 and 12 in the longitudinal direction, the ladder main body as a whole is expanded and contracted. Further, the first and second ladder members 11 and 12 have a structure in which a plurality of horizontal bars 11B and 12B are spanned over a pair of frames 11A and 12A arranged in parallel, respectively, and these frames 11A, The openings 12A having a U-shaped cross section face each other (see FIG. 2). At this time, the first ladder member 1
A second ladder member 1 having a U-shaped cross section is housed in the second ladder member 1.
As shown by the chain line in FIG. 2, the second frame 12A includes a plate made of wear-resistant resin that contacts the horizontal bar 11B of the first ladder member 11 at the lower side in FIG. 2, if necessary. The shaped member 16 is provided with a roller bearing 17 on its upper side that contacts the first frame 11A, and a roller bearing 18 on its side that makes contact with the side of the frame 11A. The two ladder members 11 and 12 can be smoothly moved relative to each other without wobbling in the vertical and horizontal directions. In addition, in FIG. 2, the first ladder member 11
The horizontal bar 11B is the horizontal bar 12B of the second ladder member 12.
Although it is located further down, the worker
B, 12B, the horizontal bar 11B is positioned closer to the front than the horizontal bar 12B.

A pair of frames 12A of the second ladder member 12
Projections 12C are formed on the proximal side (lower side in FIG. 1) of each side, and these projections 12C
One end of a wire 20 serving as a traction member is connected to each of the . As shown in FIG. 2, these wires 20 are routed around a pulley 22 provided at the tip side (upper side in FIG. 1) of the frame 11A of the first ladder member 11, and the other end is connected to the extension means 30 provided on the base end side of the first ladder member 11, that is, connected between the first and second ladder members 11 and 12. At this time, when the wire 20 is pulled toward the extension means, the ladder main body 10 is moved in the direction of extension, and when the wire 20 is pulled toward the protrusion, the ladder main body is moved in the direction of contraction. It's summery.

Details of the stretching means 30 are shown in FIGS. 3 to 5. In these figures, the extension means 30 are connected to the frame 1 of the first ladder member 11.
A pair of reels 33 for winding the wire 20 on the outside of the ladder member 1A, and a bush 3 which also serves as a horizontal beam and is spanned between the pair of frames 11A of the first ladder member 11.
a shaft 32 that is inserted through the shaft 8 and connects the reel 33;
, a first drum 34 fixed outside the reel 33, and a pair of constant output springs 37 whose tips are attached to the outer periphery of the first drum 34. Each of the constant force springs 37 has its base end connected to the frame 11A through the casing 31.
is urged in the direction (direction shown by arrow P in FIG. 5) to be rewound to the second drum 35 attached to the
As a result, the first drum 34 and reel 33 are rotated in the P direction with a constant torque, and the wire 20
is moved in the direction in which it is wound onto the reel 33, and the ladder main body 10 is extended.

A clutch 41 is attached to one of the two casings 31. This clutch 41
is a handle 41A connected to a shaft (not shown)
, a ratchet mechanism (not shown) that allows the shaft 32 to rotate only in the normal rotation direction (in the direction of arrow P in FIG. A ratchet mechanism (not shown) that allows rotation only in the direction of arrow Q) is provided, and these ratchet mechanisms are switchable. here,
This clutch 41, the shaft 32, the reel 33, and the wire 20 constitute a locking means 40. At this time, if the clutch 41 is set to allow rotation of the shaft 32 only in the normal rotation direction, the biasing force of the constant output spring 37 to be rewound onto the second drum 35 causes the first drum 34 and the reel to be rewound onto the second drum 35. 33 and the handle 41A are rotated in the forward rotation direction (in the direction of arrow P), the wire 20 is wound onto the reel 33, and a force in the direction of contraction is applied between the ladder members 11 and 12, causing the wire 20 to be paid out from the reel 33. Even if the first and second ladder members 11, 1 are pulled in the opposite direction, rotation of the shaft 32, etc. in the reverse direction (Q direction) is prevented.
2 is prevented from contracting, while the clutch 41 is allowed to rotate only in the reverse direction (Q direction).
1 and the reel 33 in the reverse direction, the constant force spring 37 is moved from the first drum 34 to the second drum 34.
While being wound onto the drum 35, the wire 20 is allowed to move in the direction in which it is unwound from the reel 33.
The second ladder members 11 and 12 can be moved relative to each other in the direction of contraction.

A method of using the telescoping ladder having such a configuration will be explained with reference to FIGS. 6 and 7. In addition, in FIG. 6 and FIG. 7, for convenience of explanation, the distance between both frames 11A and 12A is increased, and illustration of the horizontal beams spanning these frames is omitted.

First, as shown in FIG. 6, the ladder body 10 of the telescoping ladder is contracted, and the constant force spring 37 is wound around the first drum 34 so that the ladder body 10 can be extended. Ok,
In this state, the ladder is transported to a predetermined location such as a construction site.

After the telescoping ladder is transported to a predetermined location such as a construction site, the ladder is placed against the ladder and the clutch 41 of the locking means 40 is set in such a state that the shaft 32 can rotate only in the normal rotation direction (direction P). Then, due to the biasing force of the constant force spring 37 wound around the second drum 35, the first drum 3
4 is rotated in the direction of the arrow P, and the reel 33 rotates integrally with the first drum 34 while winding the wire 20. As a result, the wire 20 is pulled in the direction in which it is wound around the reel 33, and the second ladder member 12 moves in the direction away from the first ladder member 11, that is, the ladder main body 10 extends. Ladder body 1
0 is extended, the worker moves the horizontal beam 11B, 1
Climb 2B and work at heights. At this time, even if a downward force is exerted on the second ladder member 12 and the wire 20 is pulled in the direction in which it is paid out from the reel 33, rotation of the reel 33 in the reverse direction (Q direction) is prevented. Therefore, the ladder main body 10 does not shrink. In order to fix the second ladder member 12 at a predetermined height, the handle 41A of the clutch 41 is fixed by a suitable means such as a chain. This prevents the second ladder member 12 from being extended any further.

Thereafter, when the work using the telescoping ladder is completed, the ladder is retracted.To do this, the clutch 41 is switched so that the shaft 32 is rotated in the reverse direction (Q
direction) so that only the handle 41A is rotated.
The first drum 34 and the reel 33 are rotated in the Q direction while resisting the biasing force of the constant force spring 37. Then, movement in the direction in which the wire 20 is unwound from the reel 33 is allowed, the second ladder member 12 is moved downward by its own weight, and the constant force spring 37 is wound from the second drum 34 to the first drum 34. taken. At this time, even if you release your hand from the handle 41A, the shaft 32 rotates only in the Q direction and is prevented from rotating in the P direction, so the wire 20 is wound up by the biasing force of the constant output spring 37 and the ladder body 10 is rotated. is never expanded.

According to this embodiment, the first and second ladder members 11 and 12 are moved so that the ladder main body 10 is extended via the traction member (wire 20) by the urging force of the constant output spring 37 of the extension means 30. Since the ladder is relatively moved, it does not take much effort to extend the telescoping ladder. Furthermore, since the constant force spring 37 is used instead of the motor etc. to extend the ladder main body 10, the structure of the device can be simplified. Furthermore, since the locking means 41 is provided, it is possible to easily extend and retract the ladder main body 10, and to prevent the ladder main body 10 from contracting during work. Furthermore, since the constant force spring 37 is used as the spring, the ladder main body 10 can be extended over a long stroke with a constant force.

Next, a second embodiment will be described based on FIGS. 8 to 11. This second embodiment is an example applied to a triple ladder. This second embodiment differs from the first embodiment in the structure of the ladder body and the connection structure of the traction member, but the other structures such as the extension means and the method of use are the same as in the first embodiment. For convenience of explanation, the telescoping ladder is simply illustrated in FIGS. 10 and 11 as in FIGS. 6 and 7.

In FIG. 8, which shows the front of the ladder, the ladder body 10 of the second embodiment comprises a first ladder member 11 and a second ladder member 21 nested in the first ladder member 11.
The ladder member 12 is composed of a third ladder member 13 nested in the second ladder member 12.
The openings of the U-shaped cross sections of these frames 11A to 13A face inward in frames 11A and 12, and face outward in frame 13A.

Wire 20 as traction means in the second embodiment
consists of two pairs of wires, a total of four wires, and one set of wires 20A connects the first and second ladder members 11 and 12.
The remaining 1
As shown in FIG. 9, the set of wires 20B has one end connected to a protrusion 11C formed on the inner surface of the first ladder member 11, and is provided at the tip of the second ladder member 12. It is connected to a protrusion 13C formed on the inner side of the base end of the third ladder member 13 by passing around the pulley 22. Here, the 10th
As shown in FIG. 11, the wire 2
When 0A is pulled toward the expansion and contraction means 30 side, the second
The ladder member 12 is moved in a direction away from the first ladder member 12, and as the second ladder member 12 moves, the wire 20B is also pulled toward the extension means 30, and the third ladder member 13 becomes the second ladder member. On the other hand, when the wire 20B is pulled toward the projection 13C, the third and second ladder members 13 and 12 are moved toward the first ladder member 11. Therefore, when the wire 20A is biased toward the extension means 30 by the constant output spring 37, the wire 20B is also biased in the same direction as the wire 20A via the second ladder member 12.

In addition, in FIG. 9, the horizontal bar 11 of the first ladder member 11
B, the horizontal bars 12B of the second ladder member 12 and the horizontal bars 13B of the third ladder member 13 are left in the order of horizontal bars 13B, horizontal bars 12B, and horizontal bars 11B from top to bottom in the figure. However, the workers
When climbing B, from the front side, horizontal rung 11B, horizontal rung 1
2B, and the horizontal bar 13B are arranged in this order.

According to such a second embodiment, the same effects as those of the first embodiment can be achieved.

It should be noted that the telescoping ladder to which the present invention is applicable can be applied to ladders having four or more steps, in addition to the two-step and three-step ladders of the above-mentioned embodiments. Further, in each of the above embodiments, the spring is a constant output spring, but in the present invention, a clockwise spring type spring may also be used. moreover,
In addition to being wound on a reel 33, the wire 20 may be directly connected to the tip of a constant force spring or a clockwork spring whose base end is attached to the shaft 32. Further, the reel 33 may be arranged outside the frame 11A of the first ladder member 11 as in the embodiment described above, or may be arranged inside the frame 11A as shown in FIG. . Further, the traction member is the wire 20
In addition, ropes made of chain, synthetic or natural fibers such as hemp may also be used. Furthermore, instead of the pulley 22, the traction member may be hung around as a simple protrusion.

[Effects of the Invention] According to the present invention as described above, the structure of the extendable ladder can be simplified, and the ladder can be extended without any effort.

[Brief explanation of the drawing]

FIG. 1 is a front view of the first embodiment of the present invention, FIG. 2 is a sectional view taken along the line - in FIG. 1, and FIG.
4 and 5 are cross-sectional views taken along lines - and - in FIG. 3, and FIGS. 6 and 7 are explanatory diagrams of the operation of the first embodiment. hand,
FIG. 6 shows the ladder main body in a retracted state, and FIG. 7 shows the ladder main body in an extended state. FIG. 8 is a front view of the second embodiment of the present invention, and FIG. 9 is a front view of the second embodiment of the present invention.
10 and 11 are explanatory diagrams of the operation of the second embodiment, in which FIG. 10 shows the ladder main body in a retracted state, and FIG. 11 shows the ladder main body in an extended state. Indicates the condition. FIG. 1 is a front view of main parts showing a modification of the stretching means. 10...Ladder main body, 11-13...Ladder member,
20... Wire as a traction member, 30... Extension means, 37... Constant force spring, 40... Locking means.

Claims (1)

[Claims for Utility Model Registration] (1) A ladder main body that has a plurality of ladder members and is expandable and retractable by relative movement of these ladder members, and when pulled to one side between the plurality of ladder members, the ladder main body a traction member connected so that the ladder main body contracts when the ladder main body is extended and pulled to the other side; an extension means having a spring that biases the traction member so that the ladder main body extends; and a relative member in the direction in which the ladder member contracts. A telescoping ladder characterized by comprising a locking means capable of preventing movement. (2) The telescoping ladder according to claim 1, wherein the spring is a constant force spring.