JPH08270345A - Extension ladder - Google Patents

Abstract

PURPOSE: To eliminate the danger of a latch being released inadvertently even if an extension ladder is moved with its upper ladder gripped by enabling the end of a lock lever in an approximately horizontal position to be engaged with a rung of the upper ladder when an operating rope is not pulled. CONSTITUTION: When an operating rope 17 is pulled, a rope lever 15 is rotated downwards against the force of a spring. Then the end of the lever comes to a position where it is not engaged with any rung 3a of an upper ladder 3, so unobstructing the rise and fall of the upper ladder 3. In that state, when the operating rope 17 is further strongly pulled, the upper ladder 3 is extended to rise. When the rope is released in a desired position, a latch 6 is latched with a rung 2a to hold the upper ladder in that position. In that sate, a lock lever 16 is restored to a horizontal position. To retract and lower the upper ladder 3, the ladder is raised a certain distance by pulling of the rope 17, then an unlocking piece 8 enters an operating state, the ladder 3 is lowered, and a bracket 5 becomes engaged with a stopper 18 when the ladder 3 is in its most retracted position. A safe extension ladder is thus provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a telescopic ladder used for work in high places.

[0002]

2. Description of the Related Art As shown in FIGS. 1 and 2, a telescopic ladder of this type is arranged over a lower ladder 2, an upper ladder 3 which extends and retracts along the lower ladder 2, and both ladders 2, 3. An operating rope 17 and a hooking device 6 for engaging and holding the upper ladder 3 in a required expansion and contraction position. By pulling the operating rope 17, the upper ladder 3 is lifted and extended along the lower ladder 2 so that the hooking device. When the engaging piece 7 of 6 passes an arbitrary step bar 2a of the lower ladder 2, the engaging piece 7 is urged by a spring to engage with the step bar 2a, and the tension of the operation rope 17 is released immediately after the passing. The upper ladder 3 is held at the engaging position by the engaging piece 7 engaging with the step rail 2a. When the upper ladder 3 is contracted and lowered, the operation rope 17
Is further pulled to raise the upper ladder 3 until the engagement release piece 8 of the engagement device 6 is higher than the step rail 2a, and then the tension of the operation rope 17 is released, and the engagement release piece 8 engages the engagement portion of the engagement piece 7. Since 7a is closed, the engaging piece 7 contracts and descends without engaging the step rail 2a while the upper ladder 3 is descending. In this way, the upper ladder 3 can be expanded and contracted up and down by pulling the operation rope 17, and the engaging device 6 can be engaged with the arbitrary step 2a of the lower ladder 2 to adjust the expansion and contraction to an arbitrary length. The lower end of the upper ladder 3 is engaged with the stopper 18 provided at the lower end of the lower ladder 2 and is held at the lowermost position.

[0003]

However, in the structure of the telescopic ladder as described above, the engaging piece 7 of the engaging device 6 engages with the step rail 2a of the lower ladder 2 when the engaging release piece 8 is not in the operating state. The upper ladder 3 is held so as not to descend further, and even when the engagement release piece 8 is in the operating state, the lower end of the upper ladder 3 is held at the lowermost position by engaging with the stopper 18, When the ladder 3 extends and rises, the ladder 3 can be freely raised to the maximum extension position, and further, when the upper ladder 3 is extended and raised for a certain distance or more from the state where the engaging piece 7 is engaged with the step rail 2a, the engaging release piece 8 is released. Since it will be in a working state, for example, while the climbing work is performed on the roof using this extension ladder 1, the extension ladder 1 is mounted on the roof to change the work place.
When the telescopic ladder 1 is laterally moved while rolling by holding the upper end of the upper ladder 3, the upper ladder 3 extends and rises by a certain distance or more to bring the engagement releasing piece 8 into the operating state, and after moving, the upper ladder 3 There is a possibility that a situation may occur in which the upper release ladder 3 is maintained in its contracted and lowered state even though the engagement release piece 8 is in the operating state due to the engagement with the upper portion of the roof and the roof eaves, In that case, when a load is applied to the upper ladder 3 of the expandable ladder 1 in order to descend from the roof, the upper ladder 3 may contract and descend at once, and if the upper part of the expandable ladder 1 is moved while holding it, the engagement release piece It was necessary to make sure that No. 8 was not in operation.

Further, if the upper ladder 3 side is held during transportation, the lower ladder 2 cannot be lifted up, so it is necessary to re-hold it after contracting it. Also, during transportation, the upper ladder 3 is required.
When the side became lower, it sometimes stretched due to gravity.

As described above, the conventional telescopic ladder 1 has a problem that it is inconvenient because of the duty of caution in handling.

In view of the above-mentioned conventional problems, the present invention does not hinder the expansion / contraction raising / lowering operation of the upper ladder, and there is a possibility that the engaging device may be unexpectedly released even when the upper ladder is moved. The purpose is to propose a telescopic ladder that can be eliminated and whose upper ladder does not extend and rise unexpectedly.

[0007]

In order to achieve the above object, the present invention provides a lower ladder 2 and a lower ladder 2 according to the present invention, if indicated by reference numerals in the drawings. An upper ladder 3 that is engaged in a vertically movable manner, an operation rope 17 that is arranged over both the ladders 2 and 3 and that raises the upper ladder 3 along the lower ladder 2 by a pulling operation, and the upper and lower ladders 3 at required expansion and contraction positions. In the telescopic ladder 1 including the engaging device 6 which is engaged and held downward with the engaging device 6 being disengaged when the upper ladder 3 is lifted from the engaged position by a certain distance or more, the spring 16 is directed toward a substantially horizontal state. It is urged to rotate and cannot rotate upward from a substantially horizontal state. In the substantially horizontal state, the tip portion is engageable with the step rail 3a of the upper ladder 3 and the tip portion is rotated downward. Part is step ladder 3a of upper ladder 3
The lock lever 15 that is in the disengaged position is pivotally attached to a position that engages with the step bar 3a while the upper ladder 3 is located within the range between the engagement holding position and the engagement releasing position. , The end portion of the operation rope 17 is locked so that the lock lever 15 rotates downward by pulling the operation rope 17.
5 is adopted.

Further, in the second aspect, the engaging device 6
Is the engaging piece 7 that is sequentially engaged with the step rails 2a of the lower ladder 2 when the upper ladder 3 is raised, and the engaging piece 7 and the lower step rail 2a when the upper ladder 3 is lifted a certain distance or more from the engaging position. The lock lever 15 is provided between the engagement position between the engagement piece 7 and the step bar 2a and the position where the upper ladder 3 is lifted by a certain distance from the engagement position. The structure according to claim 1 is pivotally attached to a position where it engages with the step bar 3a while being positioned within the range.

[0009]

According to the first aspect of the present invention, the operating rope 17
In the state where the lock lever 15 is not pulled, the lock lever 15 is biased by the spring 16 and is in a substantially horizontal state. Further, since the lock lever 15 cannot rotate upward from the substantially horizontal state, the tip end of the lock lever 15 is located at the upper ladder 3 Even if the upper ladder 3 is lifted, the step 3a of the upper ladder 3 engages with the tip of the lock lever 15 so that the upper ladder 3 can be engaged with the lower ladder 2. Therefore, the engaging device 6 is not disengaged, and therefore the engaging device 6 is not disengaged even if the upper ladder 3 side is moved. In addition, since the upper ladder 3 does not unexpectedly extend and rise, even if the upper ladder 3 side is held during transportation, the lower ladder 2 can be integrally lifted, and the upper ladder 3 can be lifted during transportation.
When the side becomes lower, it will not stretch due to gravity.

On the other hand, when the telescopic ladder 1 is extended, the operation rope 17 is pulled so that the lock lever 15 connected to the tip of the operation rope 17 rotates downward against the urging force of the spring 16. As a result, the upper ladder 3 is lifted and extended by pulling the operating rope 17 more strongly.
The operation of pulling the operation rope 17 does not hinder the upward extension operation of the upper ladder 3.

In the second aspect, the stepping rail 2 of the lower ladder 2
A simple structure in which the engagement releasing piece 8 for preventing the engagement between the engagement piece 7 and the lower step bar 2a is brought into an operating state when the engagement position between the engagement piece 7a and the engagement piece 7 is raised by a certain distance or more. Since the engaging device 6 having such a structure is used, it can be manufactured at a low cost, and the lock lever 15 can prevent the upper ladder 3 from rising unexpectedly by a certain amount or more.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An expandable ladder according to an embodiment of the present invention will be described below with reference to FIGS.

First, the overall structure of the telescopic ladder 1 will be described.
As shown in FIGS. 1 and 2, the telescopic ladder 1 is composed of a lower ladder 2 and an upper ladder 3, and is fixed to the upper end of the lower ladder 2 and the lower end of the upper ladder 3 and directed toward the mating ladders 3 and 2 side. The upper ladder 3 is held by the guide brackets 4 and 5 which are protruded upward and downward along the lower ladder 2. 2a, 3
Reference characters a are the steps of the lower ladder 2 and the upper ladder 3, respectively.

On both sides of the lower part of the upper ladder 3, a pair of engaging devices 6 which can be engaged with the step rails 2a of the lower ladder 2 downward are provided. The engaging device 6 includes an engaging piece 7 that sequentially engages with each step bar 2a of the lower ladder 2 when the upper ladder 3 is raised, and an engaging portion of the engaging piece 7 when the upper ladder 3 is raised from the engaging position by a certain distance or more. 7a, and an engagement releasing piece 8 that is in an operation state that blocks engagement with the lower step bar 2a.

An upper pulley bracket 9 is attached at a proper lower position from the upper end of the lower ladder 2, and a lower pulley bracket 10 is attached at an appropriate upper position from the lower end of the upper ladder 3, and one or a plurality of pulleys 11 and 12, respectively. Is rotatably held. Further, as shown in FIGS. 3 and 4, the upper pulley bracket 9 is integrally formed with a slanting bracket portion 13 that projects obliquely inward toward the upper ladder 3 side. The oblique bracket portion 13 has a substantially U-shaped planar shape in which the folded-back portion is located on the front end side, and the upper end portion of the substantially L-shaped lock lever 15 is formed by the pivot pin 14 penetrating the lower base side position thereof. It is rotatably pivoted up and down. The lock lever 15 is engaged with the lower end edge of the oblique bracket portion 13 in a substantially horizontal state and cannot be further rotated upward. In the substantially horizontal state, the tip portion is a step of the upper ladder 3. It is configured so that it can be engaged with 3a and when it is rotated downward, its tip end is in the disengaged position with respect to the step bar 3a of the upper ladder 3. Also, this lock lever 15
Is urged to rotate in a substantially horizontal state by a spring 16.

The tip end of the lock lever 15 is connected to the tip end of an operating rope 17, which extends downward and is wound around the pulley 12 of the lower pulley bracket 10 on the upper ladder 3 side. After that, it is extended upward, wound around the pulley 11 of the upper pulley bracket 9 on the lower ladder 2 side and extended downward, and is connected to an appropriate place under the lower ladder 2.

In FIG. 1 and FIG. 2, 18 is a stopper for restricting the lower limit position of the upper ladder 3 by engaging the guide bracket 5 at the lower end of the upper ladder 3, and 19 is attached to the lower end of the lower ladder 2. The legs 20 are end members mounted on the upper end of the lower ladder 2 and the upper and lower ends of the upper ladder 3.

The method of using the telescopic ladder 1 having the above-described structure will be described. By pulling the lower portion of the operation rope 17 suspended along the lower ladder 2, the pulling force and the load of the upper ladder 3 lock it. The lever 15 is shown in FIG.
As shown in FIGS. 5 (c) and 5 (d), the spring 16
It rotates downward against the urging force of the upper ladder 3, and its tip end is in the disengaged position with respect to the stepping rail 3a of the upper ladder 3, and the upper ladder 3 is not hindered from moving up and down. 1
By further strongly pulling 7 the upper ladder 3 extends and rises as shown by the white arrow in Fig. 5 (d), and the pulling force of the operation rope 17 is released at the desired extension / contraction position, so that the conventional engagement is performed. Steps 2 of the lower ladder 2 to which the device 6 corresponds
It engages with a and is engaged and held in its expanded and contracted position. Further, in this state, the lock lever 15 returns to the substantially horizontal state shown in FIG.

When the upper ladder 3 is contracted and lowered, the operating rope 17 is pulled in the same manner as described above to raise the upper ladder 3 once for a certain distance or more, so that the engagement releasing piece 8 of the engagement device 6 is brought into the operating state. After that, the upper rope 3 is contracted and lowered by the operation rope 17 being unwound while the upper rope 3 is supported by the operation rope 17, without the engaging device 6 engaging with the step rail 2a below the lower ladder 2, and the uppermost ladder 3 is in the most contracted position. The guide bracket 5 at the lower end of the upper ladder 3 is engaged with and held by the stopper 18. Further, by releasing the operation rope 17 in this state, the lock lever 15 is returned to the substantially horizontal state by the urging force of the spring 16, as shown in FIG.

With the telescopic ladder 1 held by the engaging device 6 in a desired telescopic position and held by the stopper 18 in the most contracted position, as indicated by the white arrow in FIGS. 1 and 5 (b). When the upper ladder 3 is to be lifted upward, the step lever 3a of the upper ladder 3 is engaged at the tip of the lock lever 15 because the lock lever 15 cannot rotate upward in the substantially horizontal state as described above. It is possible, and Fig. 5
As shown in (b), the step rail 3a of the upper ladder 3 engages with the tip end portion of the lock lever 15, and the upper ladder 3 does not rise above the lower ladder 2 by a certain amount. As a result, the engagement device 6 is engaged. The release piece 8 does not become active.

Therefore, even if the upper ladder 3 is moved while being held, the engagement of the engagement device 6 is not released, and for example, the work place is changed while the roof is being climbed using the telescopic ladder 1. Also, when the telescopic ladder 1 is moved laterally while rolling by holding the upper end of the upper ladder 3 on the roof, the upper ladder 3 extends and rises by a certain length or more, and the engagement releasing piece 8 acts. There is no fear of becoming a state, and the engagement release piece 8
Even if you do not make sure that is not in operation,
You can safely descend from the roof.

Further, since the upper ladder 3 does not extend and rise unexpectedly, even if the upper ladder 3 side is held during transportation, the lower ladder 2 can be integrally lifted, and if the upper ladder 3 side is lowered during transportation. It does not stretch due to gravity.

[0023]

According to the first aspect of the present invention, when the operation rope is not pulled, the tip of the lock lever in a substantially horizontal state can be engaged with the step rail of the upper ladder. , Even if the upper ladder is lifted, the upper ladder does not rise above a certain level with respect to the lower ladder, and as a result, even if the upper ladder side is moved, the engagement of the engaging device is not released, and the upper ladder is Since it does not stretch and rise unexpectedly, even if you hold the upper ladder side during transportation, you can lift the lower ladder together, and even if the upper ladder side goes down during transportation, it will not expand due to gravity, When the ladder is extended, pulling the operation rope causes the lock lever to rotate downward against the biasing force of the spring and become disengaged from the step rail, so the upper ladder is extended and extended. Hinders It is not, and therefore it is possible to provide a user-friendly secure and convenient telescopic ladder, which eliminates the tedious duty of care on the handling.

According to a second aspect of the present invention, when the step is raised by a predetermined distance or more from the engaging position between the step rail of the lower ladder and the engaging piece,
It can be manufactured at low cost by using the engaging device having a simple structure in which the engaging releasing piece for preventing the engaging piece from engaging with the lower step rail can be operated, and the above effect can be obtained by the lock lever. Can be demonstrated.

[Brief description of drawings]

FIG. 1 is a side view of an embodiment of a telescopic ladder of the present invention.

FIG. 2 is a front view of the embodiment.

FIG. 3 is a cross-sectional plan view of an essential part of the embodiment.

FIG. 4 is a perspective view of an upper pulley bracket to which the lock lever of the embodiment is attached.

FIG. 5 is an operation explanatory view of the lock lever of the embodiment.

[Explanation of symbols]

 1 Telescopic Ladder 2 Lower Ladder 2a Step Ladder 3 Upper Ladder 3a Step Ladder 6 Engagement Device 7 Engagement Piece 8 Engagement Release Piece 15 Lock Lever 16 Spring 17 Operation Rope

Claims (2)

[Claims] 1. A lower ladder, an upper ladder engaged with the lower ladder so as to be able to move up and down, an operation rope arranged across both ladders to raise the upper ladder along the lower ladder by a pulling operation, and the upper ladder. In the telescopic ladder, which is engaged and held downward at each of the telescopic positions, and is brought into the disengaged state when the upper ladder is lifted from the engaged position by a certain distance or more, a substantially horizontal state is set by springs. It is urged to rotate and cannot rotate upward from a substantially horizontal state. In the substantially horizontal state, the tip portion is engageable with the step ladder of the upper ladder and when the tip portion is rotated downward, the tip portion is The lock lever, which is in the disengaged position with respect to the rung of the upper ladder, is pivoted to a position where it engages with the rung while the upper ladder is located within the range between the engagement holding position and the disengaged position. And pull it out by pulling the operating rope. An extendable ladder in which the tip of the operating rope is connected to a lock lever so that the clever can rotate downward. 2. A hooking device for engaging a hooking device with a step ladder of a lower ladder when the upper ladder is raised, and a hooking piece and a step lower when the upper ladder is raised a certain distance or more from the engaging position. The lock lever is positioned within a range between the engagement position of the engagement piece and the step rail and a position elevated by a certain distance from the engagement piece. The telescopic ladder according to claim 1, wherein the telescopic ladder is pivotally mounted at a position where it engages with the cross rail during the operation.