JPH0520879Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a telescoping ladder in which an upper ladder supported by a lower ladder can be extended and contracted from the ground using a rope.

(Prior Art) Conventional telescoping ladders have had the disadvantage that workers who have used the ladder to climb onto the roof have to hold the upper ladder from the top of the roof and are unable to change the position of the hem of the ladder.

First, the structure of a conventional ladder will be explained using FIGS. 1 and 2. The lower ladder 1 is integrally equipped with a pair of vertical members 1a arranged in parallel with a distance between them, and steps 2 arranged horizontally and equally spaced between both vertical members 1a, 1a. The lower end has a lower end fitting 3 for anti-slip via a horizontal pin. 4 is a support post cover. The vertical member 1a is made of, for example, a channel-shaped member of aluminum, and the vertical member 5a of the upper ladder 5 is fitted and supported in the engagement groove extending in the longitudinal direction of the vertical member 1a, so that the upper ladder 5 is connected to the lower ladder 1. It can be slid vertically. Like the lower ladder 1, the upper ladder 5 is integrally equipped with a plurality of steps 6 at equal intervals between the vertical members 5a, 5a, and has a slide resin 7 at the lower end and a non-slip end fitting 8 at the upper end. have Conventionally, one end of a rope 11 is connected to a bracket 10 provided on a step 6a at the lower end of an upper ladder, as shown by a two-dot chain line, and the rope 11 extends upward from the bracket 10, with an intermediate portion attached to the lower ladder 1, for example. It is hung above the pulley 28 supported by the second step 2a from the top via the bracket 11', and the part that passes through the pulley 28 normally runs along the upper ladder 5, and the end of the rope 11
c hangs down to a position where it can be easily reached from the ground.

As is clear from FIGS. 2 and 3, a rectangular cylindrical bracket 12 is fixed to the inside surface of the upper ladder vertical member 5a at a position slightly above the lower end, and is supported by the bracket 12 at two points. The upper end of a substantially triangular hook 14 is rotatably supported by a portion of the first pin 13 inside the bracket 12, and the hook 14 is normally biased in the direction of arrow A by a torsion coil spring 20 installed inside the bracket 12. and the front plate 1 of the bracket 12
2a, the cam surface 14a on the lower ladder 1 side projects to a position where it collides with the step 2 of the lower ladder 1 when ascending the upper ladder 5. The shape of the cam surface 14a is a curved shape that smoothly projects toward the step 2 as it goes downward. The lower end of the hook 14 on the lower ladder 1 side is a stopper 15 that projects further downward.
At the lower end of the upper ladder 5 side, an upper end portion of a scalene triangular pawl 17 is rotatably supported via a second pin 16. Stopper 15 and pin 16 of hook 14
In between, there is provided an abutment surface 14b having a shape that fits the upper surface of the step 2 when the hook 14 abuts against the front plate 12a of the bracket as shown in FIG. The claw 17 has a flange 18 bent at right angles to its lower edge, and the distance from the pin 16 to the flange 18 is different for each part because the claw 17 is a scalene triangle. End 18a and pin 1
6 is smaller than the distance between the lower portion adjacent to the end 18a and the pin 16, and the distance between the end 18a
As shown in FIG. 3, the stopper 15 is fitted from below to be integrated with the stopper 15 so as to cover the abutting surface 14b.

When the rope tip 11c (Fig. 1) is pulled downward, the upper ladder 5 starts to rise relative to the lower ladder 1, and the hook 1
When the cam surface 14a of 4 collides with the step 2 from below, the hook 14 rotates in the opposite direction A against the elasticity of the spring 20, and the hook 14 passes the step 2 upward. However, since the claw 17 is suspended from the pin 16 in a free state as shown in FIG. It rotates in the direction (reverse B direction) and attempts to pass the step 2 upward. Then, when the upper ladder 5 is further pulled up, the pawl 17 completely passes one step 2 upward, and by repeating this operation, the upper ladder 5 is raised. In order to stop the upper ladder 5 at a predetermined position, immediately after the hook 14 crosses one step 2 (before the claw 17 crosses the step at the corresponding position), reduce the force applied to the rope tip 11c. and lower the upper ladder 5 a little. Then, the abutting surface 14b of the hook 14 comes into pressure contact with the upper surface of the step 2 that passed just before, and the lowering of the upper ladder 5 is prevented. In order to lower and store the entire upper ladder 5, the rope is loosened and the upper ladder 5 is lowered immediately after both the hook 14 and the pawl 17 pass upwardly over one step 2. Then, the flange 18 of the pawl 17 collides with the step 2 immediately below it and rotates about the pin 16 in the direction of arrow B (Fig. 3), and the upper end 18a of the flange engages with the stopper 15, and the pawl 17
and the pin 13 from the step 2 to the combined body of the hook 14.
Since a moment is applied in the reverse A direction around With this action, the robot climbs over the lower steps 2 one after another and reaches the retracted position shown in FIGS. 1 and 2.

According to the conventional structure described above, the rope tip 11c is pulled downward and the upper ladder 5 is moved relative to the lower ladder 1.
When using the ladder on the roof in an extended position with the hook 14 raised to a predetermined position and the foot 14 hung on the step 2 at the corresponding position, the worker who has climbed onto the roof can lower the lower ladder 5 from the top of the roof. When attempting to change the installation position of the ladder (the grounding position of the anti-slip lower end fitting 3) by lifting the upper end, the combined body of the hook 14 and pawl 17 may pass upward through one step 2. There is a possibility that the upper ladder 5 cannot be locked. For this reason, when shifting the position of the ladder to the side, the operator must operate the ladder from the ground, which makes it cumbersome to move up and down the ladder.

(Effect of the invention) In order to solve the above-mentioned conventional problems, the present invention has the purpose of, for example, when lifting the upper ladder 5 upward from the roof, the upper ladder 5 is moved by a certain amount H (the claw 17 is directly above the lower ladder 1). The purpose is to prevent the vehicle from rising above the range (in which it passes above the step 2).

(Structure of the invention) The invention consists of a lower ladder, an upper ladder that is slidably supported with respect to the lower ladder, a base end connected to the lower end of the upper ladder, and a middle part passing through a pulley at the upper end of the lower ladder. A rope for ascending and descending the upper ladder, the tip of which hangs down from there, and an abutment surface that is supported by a first pin parallel to the steps on the upper ladder and is normally biased to a position where it engages with the steps on the lower ladder. In an extendable ladder, the ladder has a hook that has a hook, and a claw that hangs from the second pin at the lower end of the hook on the side opposite to the lower ladder, colliding with the step of the lower ladder when descending, and covering the abutting surface of the hook. One end is supported by a third pin provided parallel to the rung and above the first pin, and the other end is biased so as to normally protrude into a locking position where it collides with the lower surface of the step of the lower ladder. The base end of the rope is connected to the lock lever, and when pulling the tip of the rope to pull up the upper ladder, the lock lever stands up to a position where it does not collide with the step of the lower ladder, and the upper end of the upper ladder is raised. When pulling up the upper ladder, the lock lever collides with the underside of the lower ladder before the claw moves upward over the upper step.

(Example) Upper ladder lifting rope 11 drawn on the left end of Fig. 1
The base end 11a of the lock lever 22 (the fourth
The rope 11 rises from the lock lever 22, and the middle part passes above the pulley 28 at the upper end of the lower ladder 1 and hangs down from there. It is within reach. One end 22a of the lock lever 22 has a third pin 23 parallel to the step 6 of the upper ladder 5.
The third pin 23 is rotatably supported by the upper ladder 5.
Both ends are supported by a case 24 fixed to the vertical member 5a directly above the bracket 12 (FIG. 5).
The lock lever 22 protrudes laterally from the third pin 23 toward the lower ladder 1 side, and is elastically seated on a stopper 26 formed by the side wall of the case 24 by the action of the tension spring 25. Stepping ladder 2 of ladder 1 overhangs into the passage.

The relationship between the attachment positions of the lock lever 22, hook 14, and pawl 17 is determined as follows. That is, when a worker on the roof pulls up the upper end of the upper ladder 5 in the operating state where the hook 14 is engaged with the step 2 as shown in FIG. Before moving upward over the step 2 that was in contact with the step 2 (FIG. 6), the other end 22b of the lock lever collides with the lower surface of the step 2 above it, and the claw 17 moves the step 2 upward. Its mounting position is determined so that it does not cross over.

When no downward force is applied to the rope tip 11b, such as when a worker pulls up the upper ladder 5 from the roof, the lock lever 22 is moved to the fourth position.
Since the posture shown in Fig. 6 is maintained, the upper ladder 5
If the upper ladder 5 rises by H in FIG. 6, the lock lever 22 collides with the lower surface of the upper step 2 before the pawl 17 crosses the step 2, so it is impossible to raise the upper ladder 5 any further with respect to the lower ladder 1. This is not possible, and from then on, the upper ladder 5 and the lower ladder 1 will ascend together. Therefore, even when the worker pulls up the upper ladder 5 from the roof, the claw 17 does not pass upward through the step 2 directly above it as shown in FIG. Even after this step, the hook 14 engages with the upper surface of the step 2 in the same way (FIG. 4), and the whole retains its function as a ladder. When the worker pulls the rope tip 11b downward from the ground, the lock lever 22 stands up against the elasticity of the spring 25 as shown in FIG. The ladder 5 can be raised further. The upper ladder 5 can also be stored downward by once moving the claw 17 above the step 2 directly above it and then loosening the rope.

(Effect of the invention) As explained above, according to the invention, even if the worker pulls up the upper ladder 5 from the roof, the claw 17 will not pass upward through the step 2, and the worker will be able to return to the ground one by one. This eliminates the need to climb down and shift the position of the ladder to the side, making it easier to handle.

In the present invention, since it is only necessary to connect the base end 11a of the rope 11 to the lock lever 22, the structure is simple and inexpensive. Further, in the present invention, since the rope 11 can be placed near the vertical member of the ladder, the rope does not interfere with the worker's ascent and descent.

[Brief explanation of the drawing]

Figure 1 is a front view of a ladder to which the present invention is applied;
The figure is a left side view, FIG.
The - sectional view, FIGS. 6 and 7 are operation explanatory diagrams corresponding to FIG. 4. 1...lower ladder, 5...
Upper ladder, 11...rope, 13...first pin, 1
4... Hook, 14b... Collision surface, 16... Second
Pin, 17...Claw, 22...Lock lever, 23
...3rd pin, 28...pulley.

Claims (1)

[Scope of utility model registration request] A lower ladder, an upper ladder that is slidably supported with respect to the lower ladder, and an upper ladder whose base end is connected to the lower end of the upper ladder and whose midway portion passes through a pulley at the upper end of the lower ladder and from which the tip hangs down. A lifting rope, a hook supported by a first pin parallel to a step on the upper ladder and having an abutting surface that hangs and is biased to a position where it engages with the step on the lower ladder; In a telescopic ladder that has a claw that hangs from the second pin at the lower end of the lower ladder and, when descending, collides with the step of the lower ladder and covers the abutting surface of the hook, the first pin is parallel to the step on the upper ladder. A lock lever is provided, one end of which is supported by a third pin provided above the ladder, and the other end of which is biased so as to normally protrude to the lock position where it collides with the bottom surface of the lower step of the lower ladder, and a rope is attached to the lock lever. When pulling up the upper ladder by connecting the base end of the rope and pulling the end of the rope, the lock lever should stand in a position where it does not collide with the step of the lower ladder, and when pulling up the upper ladder by holding the top end of the upper ladder. This is a telescopic ladder in which the lock lever collides with the underside of the step on the lower ladder before the claw passes upward above the step above.