JP2024053435A - Telescopic leg device, and ladder body - Google Patents

Abstract

To provide a telescopic leg device of a ladder body including a remote control mechanism for facilitating expanding/contracting work of a telescopic leg member with an easy posture, which is lighter and easier to transport.SOLUTION: A telescopic leg device 5 includes: a telescopic leg member 6 that is slidably connected to a pillar 3 and constitutes a leg of the ladder body 2; a lock mechanism 7 that can lock the telescopic leg member 6 at a desired sliding position relative to the pillar 3; and a remote control mechanism 8 for remote controlling the lock mechanism 7. The lock mechanism 7 has: a locked part 71 that is formed in the telescopic leg member 6 along the length direction thereof; and a locking member 72 that is provided in the bottom of ladder body 2 and is switchable between a locked state engaged with the locked part 71 and an unlocked state where the engagement with the locked part 71 is released. The remote control mechanism 8 has a rotating member 9, an operation part 10, and a lower transmission part 11 that transmits the rotational movement of the rotating member 9 to the locking member 72 to switch the locking member 72 to an unlocked state.SELECTED DRAWING: Figure 4

Description

This invention relates to an extendable leg device that is attached to a ladder body in which multiple rungs are fixed in stages between two left and right posts, and to a ladder body equipped with the same device.

2. Description of the Related Art Among structures for working at height, such as ladders with a ladder body, dedicated stepladders, stepladders combined with ladders, and scaffolding platforms, there are known structures in which an extendable leg device is provided on the ladder body (see, for example, Patent Document 1 listed below).
This telescopic leg device comprises two telescopic leg members, one on the left and one on the right, which are slidably connected to each support pillar to form the legs of the ladder body, and two locking mechanisms, one on the left and one on the right, which lock each telescopic leg member at any sliding position relative to each support pillar.
Each locking mechanism has a locking portion such as a rack formed on each telescopic leg member along its length, and a locking member provided on the lower part of the ladder body and switchable between a locked state in which it engages with the locking portion of each telescopic leg member and an unlocked state in which it is disengaged from the locking portion. The locking member is usually provided near the lower end of the support so as to be able to swing, and has a locking portion that can be engaged with the locking portion. The locking member is also biased by a biasing member such as a spring in a direction in which the locking portion is engaged with the locking portion. Furthermore, the locking member is provided with an operating lever portion that swings the locking member against the biasing force of the biasing member in a direction in which the locking portion is disengaged from the locking portion.

Also known as a ladder telescopic leg device is one that is equipped with a remote control mechanism for remotely controlling the locking mechanism.
For example, in the case of the telescopic leg device of a ladder body described in the following Patent Document 2, the remote control mechanism includes an upper operating member provided on the back of the first upper tread located at a required number of steps from the bottom so as to perform a specified operation, and two transmission members, left and right, provided along each support pillar for interlocking the upper operating member with each locking member, and by operating the upper operating member to perform a specified operation, the locking members are switched to the unlocked position via the transmission members. The transmission members are composed of a plate-shaped lifting bar that is slidable along the length of the support pillar and descends when the operation of the upper operating member is transmitted. A pressing member is attached to the lower end of the lifting bar, which presses a required part of the locking member when the lifting bar is lowered in accordance with the operation of the upper operating member, thereby rotating the locking member in a direction to release the engagement between the locked part and the locking part.
According to the telescopic leg device equipped with the above-mentioned remote control mechanism, for example, with the ladder body standing upright, the telescopic leg members can be easily extended or retracted while remaining in a comfortable standing position.

JP 2003-193780 A JP 2019-167693 A

However, in the case of the remote control mechanism described above, the transmission member is composed of a lifting bar, which is relatively large in size and weight, so considering the portability of the ladder body, further weight reduction is desired.

The purpose of this invention is to solve the above problems by providing a ladder body telescopic leg device equipped with a remote control mechanism for easily performing telescopic leg member extension and retraction operations in a comfortable position, which is lighter in weight and easier to transport.

To achieve the above objective, this invention comprises the following aspects:

In specifying this invention, the side of the ladder body from which the worker climbs and descends will be referred to as the "front" side, the opposite side will be referred to as the "back" side (or "rear" side), and "left and right" will refer to the left and right when viewed from the front.
In addition, for the purpose of specifying this invention, the "ladder body" is intended to include anything that constitutes part or the whole of a ladder, a dedicated stepladder, a ladder/stepladder combination, or a scaffolding platform.

1) A telescopic leg device for a ladder body, comprising a ladder body having multiple rungs arranged in steps between two left and right supports, two left and right telescopic leg members slidably connected to each support to form the legs of the ladder body, two left and right locking mechanisms capable of locking each telescopic leg member at any sliding position relative to each support, and a remote control mechanism for remotely controlling the left and right locking mechanisms, each locking mechanism having an engaged portion formed along the length of each telescopic leg member, and a locking member provided at the bottom of the ladder body and switchable between a locked state in which it engages with the engaged portion of each telescopic leg member and an unlocked state in which the engagement with the engaged portion is released,
The remote control mechanism comprises two left and right rotating members arranged along each support and rotatable in a circumferential direction, an operating unit arranged above the locking members of the left and right locking mechanisms on the ladder body and/or the left and right rotating members and capable of rotating the rotating members by a specified operation, and a lower transmission unit which transmits the rotational movement of each rotating member to the locking members of each locking mechanism to switch the locking members to an unlocked state.

2) The operating part is an operating member that is provided at a position above the locking members of the left and right locking mechanisms on the ladder body and can be operated in a predetermined direction by applying an operating force;
The telescopic leg device of a ladder body as described in 1) above, characterized in that the remote control mechanism further has an upper transmission part that transmits the operation of the operating member to the rotating member to rotate the rotating member.

3) The telescopic leg device of the ladder body of 2), characterized in that the operating member is provided on the back side and/or the bottom side of at least one upper rung located several steps from the bottom.

4) The telescopic leg device of the ladder body of 3), characterized in that the operating member has an end operating part that can be operated by fingers while gripping each support.

5) The telescopic leg device of the ladder body of 4), characterized in that the end operating unit is arranged on the rear side of each support.

6) The telescopic leg device of the ladder body described in 2), characterized in that the operating member is arranged so that it can be operated by fingers while gripping each support.

7) The telescopic leg device of the ladder body of 6), characterized in that the operating member is arranged on the rear side of each support.

8) The telescopic leg device of any one of claims 2) to 7), characterized in that the upper transmission part comprises a first upper transmission part provided on the operating member and/or a part of the ladder body adjacent to the operating member and having a first engagement part, and a second upper transmission part provided on the upper part and/or a lengthwise intermediate part of the rotating member and having a second engagement part that engages with the first engagement part, and the operation of the operating member is transmitted to the rotating member via the first upper transmission part and the second upper transmission part, thereby rotating the rotating member.

9) The telescopic leg device of the ladder body of 9), characterized in that the second engagement portion is an engagement protrusion provided on the second upper transmission portion so as to protrude in a direction intersecting the rotation axis of the rotating member, and the first engagement portion is an engagement hole or engagement recess provided on the first upper transmission portion so as to engage with the engagement protrusion.

10) The telescopic leg device of the ladder body of 8) or 9), characterized in that the remote control mechanism further has an upper holding part that rotatably holds the second upper transmission part.

11) The second upper transmission portion has a side opening recess, and the upper holding portion has a side protrusion that engages with the side opening recess,
The telescopic leg device of the ladder body of 10) above, characterized in that the second upper transmission part is rotated circumferentially with the lateral convex part as a fulcrum when the operation of the operating member is transmitted via the first upper transmission member.

12) The telescopic leg device of the ladder body of 10) or 11), characterized in that the upper support part consists of an upper support member attached to each support post and/or upper rung.

13) The telescopic leg device of any one of 1) to 12) above, characterized in that the lower transmission part comprises a first lower transmission part provided at the bottom of each rotating member and having a third engagement part, and a second lower transmission part provided at the engaging member of each locking mechanism and having a fourth engagement part that engages with the third engagement part, and the rotational movement of the rotating member is transmitted to the engaging member via the first lower transmission part and the second lower transmission part, thereby switching the engaging member to an unlocked state.

14) The first lower transmission part is provided so as to rotate integrally with a rotating member, and the second lower transmission part is provided so as to operate integrally with a locking member,
the fourth engagement portion is a pressure-receiving portion provided on the second lower transmission portion so that the locking member is switched to an unlocked state by application of a force in a predetermined pressure direction intersecting with the rotation axis of the rotation member,
The telescopic leg device of a ladder body of 13) above, characterized in that the third engagement portion is a pressure protrusion that is provided on the first lower transmission portion so as to protrude in a direction intersecting the rotation axis of the rotating member and engages with the pressure-receiving portion so as to apply a force in the pressure direction when the first lower transmission portion is rotated integrally with the rotating member.

15) The telescopic leg device of the ladder body of 14), characterized in that the remote control mechanism further has a lower holding part that rotatably holds the first lower transmission part.

16) The telescopic leg device of the ladder body of 15), characterized in that at least a portion of the lower holding portion is formed by a portion adjacent to the locking members of the left and right locking mechanisms of the ladder body.

17) A ladder body having multiple rungs arranged in steps between two left and right posts, characterized in that the ladder body is equipped with any one of the telescopic leg devices described above in 1) to 16).

According to the ladder body telescopic leg device or ladder body of the present invention, the rotating member rotates by operating the operating part located at a position above the locking member of the locking mechanism to perform a specified operation, and the rotating member is then transmitted to the locking member of the locking mechanism via the lower transmission part, thereby switching the locking member to an unlocked state.Therefore, for example, with the ladder body upright, the telescopic leg member can be easily extended and retracted in a comfortable standing position.
Furthermore, according to the ladder body telescopic leg device or ladder body of the present invention, the size and weight of the corresponding rotating member can be reduced compared to the telescopic leg device described in Patent Document 2, in which a plate-shaped lifting bar is used as a long transmission member, thereby making the entire device lighter and improving transportability.

FIG. 1 shows a ladder/stepladder equipped with an extendable leg device according to a first embodiment of the present invention, and is a perspective view of one of the ladder bodies as viewed from the front. This is an oblique view of a part of the ladder body from the back side. 1A is a vertical cross-sectional view of a portion of the ladder body with the locking member of the telescopic leg device in the locked state, and FIG. 1B is a front view of the portion surrounded by the two-dot chain circle (P) and the portion surrounded by the two-dot chain circle (Q) is an enlarged view of the portion surrounded by the two-dot chain circle (q). 1A is a vertical cross-sectional view of a portion of the ladder body with the locking member of the telescopic leg device in the unlocked state, and FIG. 1B is a front view of the portion surrounded by the two-dot chain circle (R) and the portion surrounded by the two-dot chain circle (S) is an enlarged view of the portion surrounded by the two-dot chain circle (s). FIG. 2 is an exploded perspective view of the lower part of the telescopic leg device as seen from the rear. 1A is an exploded perspective view of a rotating member and a first lower transmission member of the telescopic leg device, and FIG. 1B is a perspective view of the state in which both members are connected. 1 shows the lower part of the telescopic leg device, where (a) is a horizontal cross-sectional view when the locking member is in a locked state, (b) is a rear view of the same, (c) is a horizontal cross-sectional view when the locking member is in an unlocked state, and (d) is a rear view of the same. FIG. 2 is an exploded perspective view showing an upper tread and an operating member. 4A is a perspective view showing a rotating member, a first upper transmission member, a second upper transmission member, and an upper holding member of the telescopic leg device, and FIG. 4B is a perspective view showing these members exploded. This is a vertical cross-sectional view showing the upper structure of the telescopic leg device, in which (a) shows the state in which the operating member is in the unlocked non-operating position, (b) shows the state in which the operating member is in the unlocked operating position, and (c) shows the state when the ladder body is inverted upside down. 1A shows a telescopic leg device of a second embodiment of the present invention, where (a) is a rear view showing the upper structure of the telescopic leg device, and (b) is a perspective view showing the state in which the end operating unit provided on the operating member of the device is operated with fingers. FIG. 11 is a perspective view showing an upper structure of a telescoping leg device according to a third embodiment of the present invention. FIG. 13 is a perspective view showing an upper structure of a telescoping leg device according to a fourth embodiment of the present invention.

Next, an embodiment of the present invention will be described with reference to FIGS.
In each of the following embodiments, an aspect in which the extendable leg device and ladder body according to the present invention are applied to a ladder/stepladder is shown.
In the following description, the right side of each of Figures 3(a) and 4(a) will be referred to as the "front", the left side as the "back" or "rear", and "left and right" refers to the left and right when viewed from the front (for example, the left and right in each of Figures 3(b) and 4(b)).

First Embodiment
1 to 10 show a telescopic leg device and a ladder body according to a first embodiment of the present invention.
As shown in Figures 1 to 4, the ladder/stepladder (1) is made up of two ladder bodies (2) connected at the top ends thereof by hinges (not shown) so that they can be opened and closed freely. The ladder/stepladder (1) can also be used as a ladder by rotating one of the ladder bodies (2) upside down.
The two ladder bodies (2) are essentially the same shape and size, except for the fact that they are arranged facing each other from front to back, so the following will only explain one of the ladder bodies (2) with reference to the drawings. Also, since the ladder body (2) is symmetrical with respect to a plane passing through the center line of its left and right width, only the right part of the ladder body (2) is shown in each drawing, and the left part of the ladder body (2) is not shown.

The ladder body (2) is provided with two posts (3) on the left and right, and a plurality of (e.g., five) rungs (4A), (4B), (4C) secured in steps at intervals in the vertical direction between the posts (3).
The top step (not shown) forms the top plate when used as a stepladder.
An anti-opening bracket (not shown) is secured between the upper parts of the left supports (3) of the two ladder bodies (2) and between the upper parts of the right supports (3).
The ladder body (2) is provided with a telescoping leg device (5) according to the present invention.

The left and right support columns 3 of the ladder body 2 are generally made of metal material (preferably aluminum alloy material). The illustrated support columns 3 are hollow and have a generally U-shaped cross section that opens inwardly in the left and right direction.
Each of the treads 4A, 4B, and 4C is also typically made of a metal material (preferably an aluminum alloy material). The illustrated treads 4A, 4B, and 4C are hollow and have a substantially rectangular cross section. Although not shown, the upper surface (tread surface) of each of the treads 4A, 4B, and 4C has a plurality of anti-slip ridges and grooves extending in the left-right length direction and alternately formed in the front-rear width direction.
The left and right ends of the bottom step (4A) and the second step (4B) from the bottom are attached to the left and right support posts (3) via a pair of front and rear brackets (401) and (402). The left and right ends of the third step (upper step) (4C) from the bottom are inserted into the left and right support posts (3) and attached directly to the front and rear walls of the support posts (3) by, for example, rivets (403).
The shapes and mounting structures of the posts (3) and rungs (4A), (4B), and (4C) that constitute the ladder body (2) are not limited to those described above and can be modified as appropriate.

The telescopic leg device (5) provided on the ladder body (2) is equipped with two telescopic leg members (6) on the left and right that are slidably connected to each support (3) to form the legs of the ladder body (2), two locking mechanisms (7) on the left and right that can lock each telescopic leg member (6) at any sliding position relative to each support (3), and a remote control mechanism (8) for remotely controlling the left and right locking mechanisms (7).

The extendable leg member (6) is slidably inserted from its lower end into the support column (3). A grounding portion (61) is provided at the end of the extendable leg member (6) opposite the insertion side.
The telescopic leg member (6) is usually made of a metal profile (preferably an aluminum alloy profile).
As shown in Fig. 7, the telescopic leg member 6 in this embodiment has a substantially rectangular cross section. The front and rear walls of the telescopic leg member 6 are curved in a substantially U-shape so as to protrude toward each other. Slide guide protrusions 63 are formed on the front and rear edges of the left and right outer walls of the telescopic leg member 6, and these protrusions 63 are slidably fitted into vertical grooves 31 formed on the left and right outer edges of the inner surfaces of the front and rear walls of each support 3. An internally enlarged groove 64 that opens inwardly in the left and right direction is formed on the left and right inner walls of the telescopic leg member 6.
The upper end of the telescopic leg member (6) is provided with a retaining portion (62) for preventing the telescopic leg member (6) from falling off the support post (3). The retaining portion (62) is made of a retaining cap (62) fitted and fixed to the upper end of the telescopic leg member (6). The retaining cap (62) has an inward protrusion (621) that protrudes inward in the left-right direction. This inward protrusion (621) abuts against the upper edge of the cover member (404) described below, thereby preventing the telescopic leg member (6) from falling off the support post (3).
In addition to being slidably inserted into the hollow support as described above, the extendable leg member may also be slidably connected to the outside of the support (for example, on the outside in the left-right direction).

3 to 5 and 7, the locking mechanism (7) has an engaged portion (71) formed along the length of each of the telescopic leg members (6), and a locking member (72) that is provided at the bottom of the ladder body (2) and can be switched between a locked state in which it engages with the engaged portion (71) of each of the telescopic leg members (6) and an unlocked state in which it is disengaged from the engaged portion (71). The locking mechanism (7) also has a biasing member (73) that biases the locking member (72) in a predetermined direction so that the locked state is maintained.
The engaging portion (71) can be constituted, for example, by a rack (71) provided on the inner left-right surface of each telescopic leg member (6) and having a number of teeth (711) arranged in the longitudinal direction of the telescopic leg member (6).
The locking member (72) is attached near the lower end of each post (3) of the ladder body (2), more specifically, to the front and rear brackets (401) for attaching the left and right ends of the lowest rung (4A) to the posts (3), so as to be freely swingable about a swing axis (720) extending in the front-to-rear direction.
The engaging portion (721) extends outward in the left-right direction from a center portion (723) through which the pivot shaft (720) is inserted, and has teeth (721a) at its tip portion that can mesh with the teeth (711) of the rack (71).
The biasing member (73) is composed of a spring (73) that biases the locking member (72) in a direction (counterclockwise direction in Figures 7(b) and 7(d)) in which the teeth (721a) of the locking portion (721) mesh with the teeth (711) of the rack (71).
The locking member 72 is provided with an operating lever portion 722 extending inwardly in the left-right direction from a center portion 723. By applying an upward operating force to the operating lever portion 722, the locking member 72 is swung in a direction D (clockwise direction in FIGS. 7(b) and 7(d)) in which the teeth 721a of the locking portion 721 disengage from the teeth 711 of the rack 71 against the elastic force (biasing force) of the spring 73.
In other words, the locking member (72) can be switched between a locked state in which the teeth (721a) of the locking portion (721) engage with the teeth (711) of the rack (71) and an unlocked state in which the teeth (721a) of the locking portion (721) disengage from the teeth (711) of the rack (71) by swinging it in a predetermined direction.
The spring (73) is interposed between the upper surface of the operating lever portion (722) of the locking member (72) and the lower surface of the lowest step bar (4A) so as to be freely expandable in the vertical direction. The locking member (72) is formed with a spring holding portion (724) extending upward from the middle position of the upper surface of the operating lever portion (722), and the lower end of the spring (73) is inserted and held between the spring holding portion (724) and the center portion (723).
A metal cover member (404) having a generally U-shaped cross section is fitted over the lower end of each support (3) so as to cover the opening of each support (3). The front and rear brackets (401) are attached to the front and rear walls of the support (3) from above the front and rear walls of the cover member (404) with rivets (405). The cover member (404) has an upper communication window (404a) formed in its upper part for positioning the first lower transmission member (110) described later at a predetermined mounting position, and a lower communication window (404b) formed in its lower part for exposing some of the teeth (711) of the rack (71). The teeth (721a) of the locking portion (721) of the locking member (72) are engaged with the teeth (711) of the rack (71) through the lower communication window (404b).
The locking mechanism is not limited to the illustrated embodiment and can be modified as appropriate. For example, the locking member may be provided below the lowest step bar (4A) as illustrated, or may be incorporated inside the step bar (4A) or provided above the step bar (4A).

The telescopic leg device (5) and ladder body (2) according to the present invention are characterized in that they are equipped with a remote control mechanism (8) having the following configuration.
That is, the remote control mechanism (8) has two rotating members (9), one on the left and one on the right, which are arranged along each of the supports (3) and can rotate circumferentially, an operating unit (10) which is arranged at a position above the locking members (72) of the left and right locking mechanisms (7) on the ladder body (2) and can rotate the rotating members (9) by a specified operation, and a lower transmission unit (11) which transmits the rotational movement of each rotating member (9) to the locking members (72) of each locking mechanism (7) to switch the locking members (72) to an unlocked state.
It is sufficient that at least one operating unit (10) is provided corresponding to each rotating member (9), but an operating unit (10) may be provided at each of a plurality of height positions (for example, two height positions corresponding to the upper part and the intermediate part of the length of the rotating member (9)).
The operating section (10) of this embodiment is provided above the locking members (72) of the left and right locking mechanisms (7) of the ladder body (2) and is made up of an operating member (10) that is operable in a predetermined direction when an operating force is applied to it. Accordingly, the remote control mechanism (8) is further provided with an upper transmission section (12) that transmits the operation of the operating member (10) to the rotating member (9) to rotate the rotating member (9).
However, the operating portion may be provided integrally with the upper portion and/or the intermediate portion of each rotating member (9), in which case the upper transmission portion can be omitted.

The rotating member (9) is for transmitting the operation of the operating part (10) provided at the top of the ladder body (2) to the locking member (72) of the locking mechanism (7) provided at the bottom of the ladder body (2), and is made of a long material extending along the length of the support (3). More specifically, the rotating member (9) can be made of, for example, a rod or tube made of metal, synthetic resin, or the like. When the rotating member (9) is made of a rod or tube, the thickness (outer diameter) relative to the width of the opening of the support (3) can be made small, which makes it easier to attach, for example, a stopper cap (62) to the upper end of the telescopic leg member (6) housed inside the support (3), improving assembly.
The length of the rotating member 9 may be appropriately set within a range that provides the above-mentioned functions. In addition, the thickness (outer diameter) of the rotating member 9 is not particularly limited, but in consideration of weight reduction, it is preferable to make it thin (small) within a range that ensures the transmission function by the rotational motion.
The illustrated rotating member 9 is disposed near the opening of the support 3, more specifically, at a position close to the inner edge in the left-right direction of the rear wall of the support 3. However, the location of the rotating member 9 is not limited to the above, and it may be disposed, for example, inside the support 3.
The rotating member (9) is held circumferentially rotatably by a predetermined holding means, which will be described later.

The operating portion (10) is provided for an operator to perform a switching operation of the locking member (72) of the lock mechanism (7) from a remote position above the locking member (72).
In this embodiment, the operating member (10) constituting the operating part (10) is provided on the back side of the step (upper step) (4C) located on the third step counting from the bottom of the ladder body (2). The operating member (10) may be provided on the lower side of the step (4C), or may be provided across the back side and lower side of the step (4C) (see the third and fourth embodiments and Figures 12 and 13 described later). The operating member (10) may be provided on the back side and/or lower side of the step (upper step) (4C) located on the third step counting from the bottom, or on the back side and/or lower side of the step (4B) located on the second step from the bottom or the step (not shown) located on the fourth step or higher from the bottom, depending on the size of the ladder body, the mode of use, etc.

In a preferred embodiment, the operating unit (10) is configured to be able to remotely control the left and right locking mechanisms (7) separately. In a more preferred embodiment, the operating unit (10) is configured to be able to remotely control the left and right locking mechanisms (7) separately and to remotely control both locking mechanisms (7) simultaneously.
As an example of the latter aspect, the operating unit (10) of this embodiment is composed of two left and right operating members (10) attached to the rear surface of the approximately left and right halves of the upper step (4C) so as to be able to swing freely around an axis extending in the left-right direction and to be arranged close to each other (see Figs. 3 and 4). By operating these operating members (10) individually or simultaneously to swing them in a predetermined operating direction, more specifically, in a direction (A) approaching the rear surface of the upper step (4C) (counterclockwise direction in Figs. 10(a) and (b)), the locking members (72) of the left and right locking mechanisms (7) are switched to an unlocked state individually or simultaneously via the upper transmission part (12), the rotating member (9), and the lower transmission part (11). Furthermore, according to the operating member (10) of the above aspect, the swinging operation can be easily performed with the fingers while holding the upper step (4C), and since the two operating members (10) are arranged close to each other, they can be operated simultaneously with one hand, and are excellent in operability.
As shown in detail in Figures 8 and 10, each operating member (10) has an operating member body (101) that is long in the left-right direction. The operating member body (101) is a flat, hollow member made of, for example, a metal profile (preferably an aluminum alloy profile) or a synthetic resin molding, and has an inclined wall portion (101a) that extends diagonally upward and forward at its upper edge. A rearward-curved engagement protrusion (101b) for forming a hinge is formed at the tip edge of the inclined wall portion (101a).
Meanwhile, a hinge-forming fitting groove (41) extending in the left-right direction is formed in the upper edge of the back surface of the upper tread (4C). The hinge-forming fitting groove (41) has a cross section that extends obliquely upward and forward from the upper edge of the back surface of the upper tread (4C), and its innermost portion is curved toward the rear.
The hinge-forming mating protrusion (101b) of the operating member body (101) is inserted into the hinge-forming mating groove (41) of the upper tread (4C) from its one end opening and engaged so as to be freely rotatable, whereby the operating member body (101) is attached to the back side of the upper tread (4C) so as to be swingable around the mating protrusion (101b).
An inner end cap (102) is fitted over the inner end of the operating member body (101) adjacent to the longitudinal center of the upper tread (4C) of the left and right ends of the operating member body (101). The inner end cap (102) is made of, for example, a synthetic resin molded product, and is fixed to the left and right inner end of the operating member body (101) by fitting an insertion portion (102a) that is formed so as to protrude from one side and has a generally cross-shaped cross section into the inner end of the operating member body (101).
An operating member returning leaf spring portion (operating member returning biasing portion) (102b) is formed integrally with the inner end cap (102). The leaf spring portion (102b) is roughly tongue-shaped when viewed from the front, and extends obliquely forward in a curved shape from the inner end cap (102) outward in the left-right direction and is interposed between the operating member main body (101) and the back surface of the upper tread (4C). The spring elasticity (biasing force) of the leaf spring portion (102b) biases the operating member (10) in a direction away from the back surface of the upper tread (4C).
The upper step (4C) is formed with an upper protruding wall portion (42) that protrudes toward the back side so as to be continuous with the upper surface of the upper step. Each operating member (10) is disposed below this upper protruding wall portion (42) (see FIG. 10). According to the above embodiment, not only when the ladder/stepladder (1) is used as a stepladder, but also when one of the ladder bodies (2) is turned upside down and used as a ladder, the operating member (10) does not appear on the front (climbing surface) or top (tread surface) side of the upper step (4C), so there is no risk of it interfering with use.

The upper transmission part (12) is for transmitting the action of the operating member (10) to the rotating member (9), and is composed of a first upper transmission part (12a) and a second upper transmission part (12b).
The first upper transmission part (12a) is provided on the operating member (10) and has a first engagement part (121). The second upper transmission part (12b) is provided on the rotating member (9) and has a second engagement part (122) that engages with the first engagement part (121). The operation of the operating member (10) is transmitted to the rotating member (9) via the first upper transmission part (12a) and the second upper transmission part (12b), thereby rotating the rotating member (9) in a predetermined unlocking direction (C) (counterclockwise direction in Figures 7(a) and (c)).

The first upper transmission part (12a) is composed of a first upper transmission member (12a) fixedly connected to the outer end of the operating member body (101) close to the support post (3) of the left and right ends of the operating member body (101) so as to cover the opening of the outer end. Therefore, the first upper transmission member (12a) also serves as an outer end cap of the operating member body (101).
As shown in detail in Figures 8 to 10, the first upper transmission member (12a) is generally L-shaped in side view and has a connecting portion (123) that is connected to the outer end of the operating member body (101) and an arm portion (124) that extends forward from the lower portion of the connecting portion (123), and can be constructed, for example, from a synthetic resin molded product.
The connecting portion (123) is fixed to the outer end surface of the operating member body (101) by a tapping screw (not shown) that passes through the connecting portion (123) and is screwed into a tapping screw hole (101c) in the lower part of the operating member body (101).
The arm portion (124) moves forward in the space below the upper tread (4C) as the operating member (10) swings in the unlocking direction (A). An engagement hole (121) is formed at the tip of the arm portion (124) so as to penetrate the arm portion in the thickness direction (left-right direction), and the engagement hole (121) forms a first engagement portion (121). The upper and lower hole edges of the engagement hole (121) are concave-arc shaped, and the front and rear hole edges are convex-arc shaped. The first engagement portion (121) may be formed by an engagement recess formed on the outer left-right surface of the tip of the arm portion (124) instead of the engagement hole.

The second upper transmission part 12b is composed of a second upper transmission member 12b fixedly connected to the upper end of the rotating member 9. Therefore, the second upper transmission part 12b rotates integrally with the rotating member 9.
As shown in detail in Figures 9 and 10, the second upper transmission member (12b) has a vertical portion (125) and an engaging protrusion (122) protruding laterally from the upper portion of the vertical portion (125), and can be constructed, for example, from a synthetic resin molded product.
A fitting recess (not shown) into which the upper end of the rotating member is fitted is formed on the lower end surface of the vertical portion (125), and this fitting recess constitutes a connection portion with the rotating member (9). In addition, a side opening recess (126) is formed on the front side of the peripheral surface of the vertical portion (125).
The engaging protrusion (122) is adapted to be inserted into the engaging hole (121) of the arm portion (124) of the first upper transmission member (12a) from the outside in the left-right direction, and constitutes a second engaging portion (122) that engages with the first engaging portion (121) consisting of the engaging hole (121).

The first upper transmission part (12a) and the second upper transmission part (12b) having the above-mentioned configuration are operated so that the second engagement part (122) engaged with the first engagement part (121) moves along the circumferential direction of the rotating member (9) when the operation of the operating member (10) is transmitted thereto.
More specifically, in conjunction with the movement (swinging) of the operating member (10) in the unlocking direction (A), the arm portion (124) of the first upper transmission member (12a) is moved forward, and the movement of the arm portion (124) is transmitted to the second upper transmission member (12b) via the first engagement portion (121) and the second engagement portion (122), causing the second upper transmission member (12b) to rotate together with the rotating member (9) in the unlocking direction (C) (counterclockwise direction in Figure 7(a)).
An outward protrusion (124e) is integrally formed on the arm portion (124) of the first upper transmission member (12a) and protrudes outward in the left-right direction toward the inside of the support column (3). When a relatively large external force acts on the operating member (10) in the direction opposite to the unlocking direction (A), this outward protrusion (124e) comes into contact with the rear wall portion of the support column (3), thereby reliably preventing the first engagement portion (121) and the second engagement portion (122) from disengaging from each other.

The remote control mechanism (8) has an upper holding part (13) that rotatably holds the second upper transmission part (12b). Since the second upper transmission part (12b) is rotatably held by this upper holding part (13), the upper part of the rotating member (9) that is provided integrally with the second upper transmission part (12b) is also rotatably held, so that the holding means can be simplified and can contribute to weight reduction.
The upper holding part (13) is composed of an upper holding member (13) fixed to at least one of the support posts (3) and the upper tread (4C). As shown in detail in Figures 9 and 10, the upper holding member (13) is formed with a side protrusion (131) protruding rearward so as to be able to engage with the side opening recess (126) of the second upper transmission part (12b). When a force is applied from the first upper transmission part (12a) with the side opening recess (126) engaged with the side protrusion (131), the forward movement of the second upper transmission part (12b) is restricted, and the force is efficiently converted into a force that rotates the second upper transmission part (12b). Therefore, when the operation of the operating member (10) is transmitted via the first upper transmission part (12a), the second upper transmission part (12b) can be smoothly rotated in the circumferential direction with the side protrusion (131) as a fulcrum.
More specifically, the illustrated upper holding member (13) has a generally U-shaped cross section, with side walls extending in the front-rear direction and front-rear walls extending outward in the left-right direction from the front-rear edges of the side walls, and can be made of, for example, a synthetic resin molded product. The above-mentioned lateral projections (131) are integrally formed on the inner left-right surfaces of the side walls. The side walls are also formed with engagement claws (132) that protrude upward, and the engagement claws (132) are adapted to be snap-engaged with the outer ends of the upper treads (4C). Furthermore, protrusions (133) are formed on the outer surfaces of the front and rear walls, and the protrusions (133) are pressed against the inner surfaces of the front and rear walls of the support (3), thereby preventing the upper holding member (13) from being displaced in the up-down direction.
The upper holding part (13) may have any function to rotatably hold the second upper transmission part (12b), and the configuration, arrangement, etc. thereof are not limited to the above embodiment. Specifically, for example, the upper holding part may be constituted by a cylindrical upper holding member that is arranged around the second upper transmission part (12b) and restricts the movement of the second upper transmission part (12b) in the front-rear and left-right directions.

The remote control mechanism 8 is also provided with a stopper 14 that can restrict the movement of the operating member 10 when the ladder body 2 is turned upside down. As shown in detail in Figure 10, the stopper 14 is disposed in a first position (see Figures 10(a) and 10(b)) that does not block the movement of the operating member 10 when the ladder-cum-stepladder 1 is used as a stepladder, whereas the stopper 14 is displaceable to a second position (see Figure 10(c)) that blocks the movement of the operating member 10 when the ladder-cum-stepladder 1 is turned upside down together with the ladder body 2 to be used as a ladder. This stopper (14) prevents the operating member (10) from moving in the unlocking direction (A) when the ladder body (2) is inverted upside down. Therefore, even if an unintended operating force is applied to the operating member (10) when an operator ascends or descends the ladder body (2) in an inverted state, the locked state of the telescopic leg member (6) by the locking mechanism (7) will not be accidentally released, and the ladder can be used safely.
In the case of the stopper (14) shown in the figure, it is provided on the base end side portion of the arm portion (124) of the first upper transmission member (12a) constituting a part of the operating member (10) so as to be able to swing about a swing axis extending in a direction intersecting the movement direction of the operating member (10), i.e., in the left-right direction. Therefore, the stopper (14) is automatically displaced between the first position and the second position by the swing of the stopper (14) due to its own weight as the ladder body (2) changes its up-down direction. Note that the displacement of the stopper may be, in addition to the above-mentioned manner, for example, by reciprocating movement in a predetermined direction due to its own weight.
The stopper (14) is symmetrical with respect to a plane passing through the swing axis, specifically, is generally bell-shaped. A recess (124a) is formed on the inner side of the base end portion of the arm portion (124) of the first upper transmission member (12a), and the stopper (14) is accommodated in the recess (124a). The stopper (14) has a half-split insertion portion (141) formed to protrude outward in the left-right direction from one end thereof, which is loosely inserted into a hole (124b) formed in the base end portion of the arm portion (124), so that the stopper (14) can swing freely around the insertion portion (141) as a swing axis (see FIG. 8).
A first abutment portion (142) is provided on the side of the stopper (14) in the first swing direction (B1) (the swing direction when used as a stepladder, see Figures 10(a) and (b)), and a first abutted portion (124c) is provided on the arm portion (124) of the first upper transmission member (12a) which abuts against the first abutment portion (142) of the stopper (14) swinging in the first swing direction (B1) to hold the stopper (14) in a first position. In addition, a second abutment portion (143) is provided on the side of the stopper (14) in the second swing direction (B2) (opposite to the first swing direction when used as a ladder, see FIG. 10(c)), and a second abutted portion (124d) is provided on the arm portion (124) that abuts against the second abutment portion (143) of the stopper (14) that swings in the second swing direction (B2) to hold the stopper (14) in the second position. The first abutment portion (124c) is formed by a part of the arm portion (124) (more specifically, the peripheral surface of the recess (124a)) located on the first swing direction (B1) side relative to the stopper (14). The second abutment portion (124d) is formed by another part of the arm portion (124) (more specifically, the peripheral surface of the recess (124a)) located on the second swing direction (B2) side relative to the stopper (14). A third abutment portion (144) is provided at the end of the stopper (14) opposite the swing shaft, and a third abutment portion (43) is provided on the upper tread (4C) so as to abut against the third abutment portion (144) when an external force is applied to the operating member (10) in the operating direction with the second abutment portion (143) abutting against the second abutment portion (124d).
In addition, the stopper (14) does not necessarily have to be provided on the first upper transmission part (12a) as described above, and may be provided at a required location other than the first upper transmission part (12a) so as to prevent the movement of any of the operating member (10), the upper transmission part (12), the rotating member (9), and the lower transmission part (11).

The lower transmission part (11) is for transmitting the rotational motion of the rotating member (9) to the locking member (72) of the locking mechanism (7), and is composed of a first lower transmission part (110) and a second lower transmission part (725).
The first lower transmission part (110) is provided on the rotating member (9) and has a third engagement part (111). The second lower transmission part (725) is provided on the locking member (72) and has a fourth engagement part (725a) that engages with the third engagement part (111). The rotational motion of the rotating member (9) is transmitted to the locking member (72) via the first lower transmission part (110) and the second lower transmission part (725), whereby the locking member (72) is switched to an unlocked state.

5 to 7, the first lower transmission part 110 is made of a first lower transmission member 110 fixedly connected to the lower end of the rotating member 9. Therefore, the first lower transmission part 110 rotates integrally with the rotating member 9.
The first lower transmission member (110) has a vertical portion (112) and a lateral protrusion (113) protruding laterally from the lower portion of the vertical portion (112), and can be constructed, for example, from a synthetic resin molded product.
A fitting recess (112a) is formed on the upper end surface of the vertical portion (112) into which the lower end of the rotating member (9) is fitted, and the fitting recess (112a) forms a connection portion with the rotating member (9).
The lateral protrusion (113) is bent into a generally arc shape in a plan view, and a third engagement portion (pressure protrusion) (111) is formed by a tip portion of the lateral protrusion (113).

The locking member (72) has an upward protrusion (725) extending upward from its center (723) as an integral part thereof, and this upward protrusion (725) constitutes a second lower transmission part (725) (see Figures 5 to 7). Therefore, the second lower transmission part (725) moves (swings) integrally with the locking member (72).
In addition, the upper protrusion portion (725) has its left-right inner surface adapted to engage with the third engagement portion (111) of the first lower transmission portion (110), and the same inner surface serves as the fourth engagement portion (pressurized portion) (725a).

When the first lower transmission part (110) integral with the rotating member (9) is rotated in the unlocking direction (C) by the rotation of the rotating member (9) in the same direction (C), the third engagement part (pressure protruding part) (111) of the first lower transmission part (110) engages with the fourth engagement part (pressurized part) (725a) of the locking member (72) and is pressed outward in the left-right direction (pressurizing direction). As a result, the locking member (72) is swung in the unlocking direction (D) and is switched to an unlocked state in which the engagement between the locking member (72) and the locked part (71) is released (see Figure 7).

The remote control mechanism (8) has a lower holding part (15) that rotatably holds the first lower transmission part (110). Since the first lower transmission part (110) is rotatably held by this lower holding part (15), the lower part of the rotating member (9) that is provided integrally with the first lower transmission part (110) is also rotatably held, so that the holding means can be simplified and can also contribute to weight reduction.
In a preferred embodiment, at least a part of the lower holding portion (15) is formed by a portion adjacent to the locking members (72) of the left and right locking mechanisms (7) of the ladder body (2) (more specifically, for example, the lowest step (4A) and/or the mounting members (404) (405) for mounting the step (4A) to the post (3)). According to the above embodiment, the burden of separately preparing and mounting the members constituting the lower holding portion (15) is reduced, thereby reducing the cost of parts and achieving further weight reduction.
As an example of the above aspect, in this embodiment, the downward convex portion (112b) formed on the lower surface of the vertical portion (112) of the first lower transmission member (110) is rotatably received by the lower wall portion (44) of the lowest step (4A). In other words, the first lower transmission part (110) is held from below by the lower wall portion (44) of the lowest step (4A). In addition, in accordance with this, a notch or hole for inserting the lower portion of the rotating member (9) is formed in the upper wall portion (45) of the lowest step (4A) as necessary (see Figures 3 and 4, etc.).
The first lower transmission member (110) is disposed at a lower position where a part of the upper surface of the vertical portion (112) thereof is adjacent to the upper edge of the upper communication window (404a) of the cover member (404). In other words, the upward movement of the first lower transmission member (110) is restricted by the upper edge of the upper communication window (404a) of the cover member (404) (see FIG. 5, etc.).
In addition, the base end of the lateral protrusion (113) of the first lower transmission member (110) is interposed between the upward protrusion (725) of the locking member (72) and the rear wall (46) of the end of the lowest tread (4A), and the first lower transmission member (110) is held from both the front and rear by these portions (725) and (46) (see Figures 3, 4, 7, etc.).
Furthermore, the first lower transmission member (110) has its vertical portion (112) interposed between the cover member (404) and rivets (405) for attaching the left and right ends of the lowest tread (4A) to the front and rear brackets (401), and the first lower transmission member (110) is held from both the left and right sides by these cover members (404) and rivets (405) (see Figures 3 to 5, etc.).
As described above, according to this embodiment, the first lower transmission part (110) is rotatably held by utilizing the lowest tread (4A) and a part of its mounting parts (404) (405) as the lower holding part (15) without preparing any special parts.
However, the lower holding portion (15) is not limited to the above embodiment, and may be configured appropriately depending on the shape and arrangement of the first lower transmission portion, etc.

Next, an example of an operation procedure for locking/unlocking the telescopic leg member (6) by the locking mechanism (7) using the remote control mechanism (8) will be described.
In other words, when the operating member (10) is gripped together with the upper step (4C) in one hand and swung in the unlocking operation direction (A) (the direction approaching the back of the upper step (4C)), the first upper transmission part (12a) formed integrally with the operating member (10) is operated in the same direction (A), thereby rotating the second upper transmission part (12b), the rotating member (9), and the first lower transmission part (110) in a predetermined unlocking direction (C). Then, the pressure projection (third engagement portion) (111) of the first lower transmission portion (110) engages with the pressure-receiving portion (fourth engagement portion) (725a) of the second lower transmission portion (725) integral with the locking member (72) and applies pressure in a predetermined pressure direction, causing the locking member (72) to swing in the unlocking direction (D), and disengaging the locked portion (71) of the telescopic leg member (6) from the locking portion (721) of the locking member (72). This allows the telescopic leg member (6) to slide freely relative to the support (3), allowing the telescopic leg member (6) to extend or retract by a required length.
When the operating member (10) is released, the elastic force of the spring (73) causes the locking member (72) to swing in the locking direction, the locking portion (721) engages with the locked portion (71), and the telescopic leg member (6) is locked again. The above-mentioned swing of the locking member (72) causes the pressurized portion (725a) of the second lower transmission portion (725) to press the pressure protruding portion (111) of the first lower transmission portion (110) in the direction opposite to the unlocking direction (D), thereby rotating the first lower transmission portion (110), the rotating member (9), and the second upper transmission portion (12b) in the direction opposite to the unlocking direction (C), and the operating member (10) is swung in the direction away from the back surface of the upper tread (4C) (the direction opposite to the unlocking direction (A)) and displaced to the standby position when not in operation. At this time, the spring elastic force of the lever returning leaf spring portion (102b) also acts on the operating member (10), so that the operating member (10) quickly and reliably returns to the standby position.

As described above, according to the telescopic leg device (5) and ladder body (2) of this embodiment, the unlocking operation of the telescopic leg member (6) is performed using the operating member (10) provided on the back of the upper rung (4C) located several steps from the bottom of the ladder body (2), so that it can be easily performed while standing in a comfortable position.
In addition, the above-mentioned unlocking operation can be performed separately for the left and right telescopic leg members (6) by operating the left and right operating members (10) separately. In addition, by operating the left and right operating members (10) simultaneously with one hand, the left and right telescopic leg members (6) can be unlocked simultaneously, which is very convenient.
Furthermore, according to the telescopic leg device (5) of this embodiment, even when the ladder/stepladder (1) is used as a ladder by inverting one of its ladder bodies (2) upside down, the operating member (10) does not appear on the front (lifting surface) or top surface (tread surface) of the upper rung (4C), so there is no risk of interference with the use of the ladder.

In addition to these effects, according to the telescopic leg device (5) and ladder body (2) of this embodiment, the remote control mechanism (8) uses a rotating member (9) as a transmission means between the engaging member (72) of the locking mechanism (7) and the operating part (10), and therefore the size and weight can be reduced compared to the conventional technology which used a lifting bar as the transmission means, thereby making it even lighter and easier to transport.
In addition, according to the telescopic leg device (5) and ladder body (2) of this embodiment, the size of the rotating member (9) relative to the support (3) can be reduced, thereby eliminating constraints such as the need to assemble the anti-slip cap last in the prior art and the need for a special structure in the lifting bar for its assembly (such as a hole or notch for passing the cap through), thereby improving assembly.

Second Embodiment
FIG. 11 shows a second embodiment of the present invention.
The telescopic leg device (5) and ladder body (2) of this embodiment are substantially the same as those of the first embodiment shown in Figures 1 to 10, except for the following points.
That is, in the case of the telescopic leg device (5) of the illustrated ladder body (2), the operating member (10X) has an end operating part (127) that can be operated by fingers while holding the support poles (3). In a preferred embodiment, the end operating part (127) is disposed on the rear side of each support pole (3).
The end operation part (127) is provided integrally with the first upper transmission member (12a) connected to the outer end in the left-right direction of the operation member main body (101). More specifically, the first upper transmission member (12a) is provided with an operation protruding wall part (127) extending outward in the left-right direction so as to be connected to the back surface of the connection part (123), in other words, a trigger part (127), which constitutes the end operation part (127). The trigger part (127) has a shape and size such that at least a part of it is disposed on the back side of the support (3), and can be operated by pulling it toward oneself with fingers (particularly the index finger and middle finger) while holding the support (3).
According to the operating member (10X) of the above aspect, the engaging member (72) of the locking mechanism (7) can be unlocked by operating the end operating part (127) with the fingers while holding the support (3) in the hand. Therefore, for example, when lifting or moving the ladder body (2) during or after unlocking, there is no need to change hands, improving convenience.
In addition, in the operating member (10X) of this embodiment, in addition to the end operating portion (127), the operating member body (101) also functions as a main operating portion, so that these can be used appropriately depending on the usage situation, etc.
The operating member (10X) of this embodiment is not limited to the remote control mechanism (8) using the rotating member (9), and can be similarly applied to, for example, a remote control mechanism using a lifting bar as described in Patent Document 2.

In addition, although not shown in the figures, it is also possible to omit the operating member body (101) and the inner end cap (102) in the operating member (10X) of the second embodiment, and to configure the operating member using only the first upper transmission member (12a) equipped with the end operating portion (127).
In this case, for example, an inclined wall portion and a mating protrusion for forming a hinge similar to those of the operating member main body (101) may be formed on the connecting portion (123) of the first upper transmission member (12a) and the first upper transmission member (12a) may be attached to the upper tread (4C) so as to be able to swing freely.
In addition, the operating member of the above embodiment is not limited to application to the remote control mechanism (8) using the rotating member (9), but can also be applied to a remote control mechanism using a lifting bar, for example, as described in Patent Document 2.

Third Embodiment
FIG. 12 shows a third embodiment of the present invention.
The telescopic leg device (5) and ladder body (2) of this embodiment are substantially the same as those of the first embodiment shown in Figures 1 to 10, except for the following points.
That is, in the case of the telescopic leg device (5) of the illustrated ladder body (2), the left and right operating members (10Y) are each provided straddling from the lower side to the rear side of the upper rung (4C).
The upper tread (4C) has a lower opening (471) formed by cutting out the rear of its lower wall. A hinge-forming fitting groove (472) extending in the left-right direction is formed in the lower edge of the inner surface of the rear wall of the upper tread (4C).
Each operating member (10Y) is provided with a curved wall portion (103) having a generally hairpin-shaped cross section and having at one end a hinge-forming fitting protrusion (103a) that is disposed inside the upper tread (4C) and rotatably fitted into the fitting groove (472) of the upper tread (4C), and a rearwardly protruding wall portion (104) that is connected to the other end edge of the curved wall portion (103) and extends rearward through the lower opening (471) of the upper tread (4C). Thus, the operating member (10Y) is freely swingable about the fitting protrusion (103a) as a swing axis.
The first upper transmission member (12Y) is connected to the outer lateral end of the upper tread (4C). The first upper transmission member (12Y) is composed of a vertical shaft portion (128a) extending in the up-down direction, an arm portion (128b) extending forward from the upper end of the vertical shaft portion (128a), and a bulging portion (128c) connected to the lower portion of the vertical shaft portion (128a) and bulging forward and having an engagement hole (121) penetrating in the left-right thickness direction. The tip portion of the arm portion (128b) is bent in a substantially L-shape toward the inside of the upper tread (4C) so as to be located above the curved wall portion (103) of the operating member (10Y).
The first upper transmission member 12Y is connected to the upper tread 4C so as to be able to swing freely, for example, by a connecting pin 128d which penetrates the base end portion of the arm portion 128b and is fitted into an upper fitting groove (not shown) formed on the underside of the upper wall portion of the upper tread 4C. The bulge 128c of the first upper transmission member 12Y is disposed below the upper tread 4C through a lower opening 471 of the upper tread 4C.
The first engagement portion (121) that engages with the second engagement portion (engagement protrusion) (122) of the second upper transmission member (12b) is configured by the engagement hole (121) of the bulge portion (128c) of the first upper transmission member (12Y). Note that the first engagement portion (121) may be configured by an engagement recess formed on the outer surface of the bulge portion (128c) in the left-right direction instead of the engagement hole (121).
When unlocking the locking member (72) of the locking mechanism (7), a downward operating force is applied by hand to the rear protruding wall portion (104) of the operating member (10Y), causing the operating member (10Y) to swing in the unlocking direction, and an upward force acts on the tip portion of the arm portion (128b) of the first upper transmission member (12Y) by the upper surface of the bent wall portion (103). As a result, the first upper transmission member (12Y) swings in the unlocking direction, and the movement is transmitted to the second upper transmission member (12b) via the first engagement portion (121) and the second engagement portion (122), causing the second upper transmission member (12b) to rotate in the unlocking direction together with the rotating member (9), and further, the rotational movement of the rotating member (9) is transmitted to the locking member (72) via the lower transmission portion (11), causing the locking member (72) to switch to the unlocked state.
When the engaging member (72) is to be switched back to the locked state, the operating force can be released by releasing the hand from the rearwardly protruding wall portion (104) of the operating member (10Y).
According to the telescopic leg device (5) and ladder body (2) of the third embodiment, substantially the same effects as those of the first embodiment are achieved.

Fourth Embodiment
FIG. 13 shows a fourth embodiment of the present invention.
The telescopic leg device (5) and ladder body (2) of this embodiment are substantially the same as those of the third embodiment shown in FIG. 12, except for the following points.
That is, in the case of the telescopic leg device (5) of the illustrated ladder body (2), one operating member (10Z) is provided on the lower side of the upper rung (4C).
The upper tread bar (4C) has a lower wall portion cut out at its front-to-rear widthwise intermediate portion to form a lower opening (471). Upright walls (471a) extending upward are formed at the front and rear edges of the lower opening (471).
The operating member (10Z) is a flat hollow plate that is long in the left-right direction and is disposed within the upper step (4C) so as to be movable up and down. The front and rear edges of the operating member (10Z) are formed with downward opening grooves (105) into which the rising wall portion (471a) of the upper step (4C) is loosely inserted, thereby restricting the movement of the operating member (10Z) in the front-rear direction.
The first upper transmission member (12Y) is the same as that of the second embodiment, and is connected to the upper tread (4C) so as to be able to swing freely, for example, by a connecting pin (128d) that penetrates the base end portion of the arm portion (128b) and is fitted into an upper fitting groove (not shown) formed on the inner surface of the upper wall portion of the upper tread (4C). The bulge portion (128c) of the first upper transmission member (12Y) is disposed below the upper tread (4C) through the lower opening (471) of the upper tread (4C). In addition, the outer end portion of the operating member (10Z) is partially cut out to allow the vertical shaft portion (128a) of the first upper transmission member (12Y) to pass therethrough.
When unlocking the locking member (72) of the locking mechanism (7), an upward operating force is applied to the bottom surface of the operating member (10Z) by hand through the lower opening (471) of the upper tread (4C), causing the operating member (10Z) to move upward, and an upward force is applied to the tip of the arm portion (128b) of the first upper transmission member (12Y) by the upper surface of the operating member (10Z). As a result, the first upper transmission member (12Y) swings in the unlocking direction, and the movement is transmitted to the second upper transmission member (12b) via the first engagement portion (121) and the second engagement portion (122), causing the second upper transmission member (12b) to rotate in the unlocking direction together with the rotating member (9), and the rotational movement of the rotating member (9) is transmitted to the locking member (72) via the lower transmission portion (11), switching the locking member (72) to the unlocked state.
When the engaging member (72) is to be switched back to the locked state, the operating force can be released by releasing the operating member (10Z).
In this embodiment, when the locking members (72) of the left and right locking mechanisms (7) are to be unlocked individually, an operating force is applied only to both the left and right portions of the bottom surface of the operating member (10Z) that is on the same side as the locking mechanism (7) to be unlocked. When the locking members (72) of the left and right locking mechanisms (7) are to be unlocked simultaneously, an operating force is applied only to both the left and right portions of the bottom surface of the operating member (10Z).
The telescopic leg device (5) and ladder body (2) of the fourth embodiment described above also provide substantially the same effects as those of the first embodiment.

In the above embodiments, examples have been shown in which the telescopic leg device and ladder body of the present invention are applied to a ladder/stepladder combination, but the present invention can also be applied to other structures for working at height that have a ladder body, such as ladders, dedicated stepladders, scaffolding, etc.

This invention is suitable for use as ladder bodies, such as ladders, dedicated stepladders, ladders and stepladders, scaffolding, and other ladder structures for working at height, as well as telescopic leg devices that are provided on the ladder bodies.

(1): Ladder/stepladder
(2): Ladder body
(3) Support
(4A): The lowest step
(4B): The second step from the bottom
(4C): The third step from the bottom (upper step)
(401): Bracket (mounting part)
(405): Rivet (mounting part)
(5): Telescopic leg device
(6) Telescopic leg member
(7) Locking mechanism
(71): Rack (engaged part)
(72): Locking member
(725): Second Lower Transmission Section
(725a): Pressurized portion (fourth engagement portion)
(8) Remote control mechanism
(9) Rotating parts
(10)(10X)(10Y)(10Z): Operation member (operation part)
(11): Lower transmission part
(110): First lower transmission member (first lower transmission part)
(111): Pressure protrusion (third engagement portion)
(12): Upper transmission section
(12a)(12Y): First upper transmission member (first upper transmission part)
(12b): Second upper transmission member (second upper transmission part)
(121): Engagement hole (first engagement portion)
(122): Engagement protrusion (second engagement portion)
(126): Side opening recess
(127): Terminal operation unit
(13): Upper holding member (upper holding part)
(131): Lateral convex part
(15): Lower holding part

Claims (17)

A telescopic leg device for a ladder body, comprising a ladder body having a plurality of rungs arranged in steps between two left and right supports, two left and right telescopic leg members slidably connected to each support to form the legs of the ladder body, two left and right locking mechanisms capable of locking each telescopic leg member at any sliding position relative to each support, and a remote control mechanism for remotely controlling the left and right locking mechanisms, each locking mechanism having an engaged portion formed along the length of each telescopic leg member, and a locking member provided at the bottom of the ladder body and switchable between a locked state in which it engages with the engaged portion of each telescopic leg member and an unlocked state in which the engagement with the engaged portion is released,
The remote control mechanism comprises two left and right rotating members arranged along each support and rotatable in a circumferential direction, an operating unit arranged above the locking members of the left and right locking mechanisms on the ladder body and/or the left and right rotating members and capable of rotating the rotating members by a specified operation, and a lower transmission unit which transmits the rotational movement of each rotating member to the locking members of each locking mechanism to switch the locking members to an unlocked state. The operating part is an operating member that is provided at a position above the locking members of the left and right locking mechanisms of the ladder body and can be operated in a predetermined direction by applying an operating force thereto,
2. The ladder body telescopic leg device according to claim 1, wherein the remote control mechanism further comprises an upper transmission section for transmitting the operation of the operating member to the rotating member to rotate the rotating member. The extendable leg device of the ladder body according to claim 2, characterized in that the operating member is provided on the back side and/or the bottom side of at least one upper rung located several steps from the bottom. The ladder body telescopic leg device according to claim 3, characterized in that the operating member has an end operating part that can be operated by fingers while gripping each support. The ladder body telescopic leg device according to claim 4, characterized in that the end operating unit is disposed on the rear side of each support. The ladder body telescopic leg device according to claim 2, characterized in that the operating member is arranged so that it can be operated by fingers while gripping each support. The ladder body telescopic leg device according to claim 6, characterized in that the operating member is disposed on the rear side of each support. The ladder body telescopic leg device according to claim 2, characterized in that the upper transmission part comprises a first upper transmission part provided on the operating member and/or on a part of the ladder body adjacent to the operating member and having a first engagement part, and a second upper transmission part provided on the upper part and/or intermediate part of the length of the rotating member and having a second engagement part that engages with the first engagement part, and the operation of the operating member is transmitted to the rotating member via the first upper transmission part and the second upper transmission part, thereby rotating the rotating member. The ladder body telescopic leg device according to claim 8, characterized in that the second engagement part is an engagement protrusion provided on the second upper transmission part so as to protrude in a direction intersecting the rotation axis of the rotating member, and the first engagement part is an engagement hole or engagement recess provided on the first upper transmission part so as to engage with the engagement protrusion. The ladder body telescopic leg device according to claim 8, characterized in that the remote control mechanism further has an upper holding part that rotatably holds the second upper transmission part. the second upper transmission portion has a side opening recess, and the upper holding portion has a side protrusion that engages with the side opening recess,
The telescopic leg device of a ladder body as described in claim 10, characterized in that the second upper transmission part is rotated circumferentially with the lateral convex part as a fulcrum when the operation of the operating member is transmitted via the first upper transmission member. The ladder body telescopic leg device according to claim 10, characterized in that the upper support part is made of an upper support member attached to each support and/or upper tread. The ladder body telescopic leg device according to claim 1, characterized in that the lower transmission part comprises a first lower transmission part provided at the lower part of each rotating member and having a third engagement part, and a second lower transmission part provided at the engaging member of each locking mechanism and having a fourth engagement part that engages with the third engagement part, and the rotational movement of the rotating member is transmitted to the engaging member via the first lower transmission part and the second lower transmission part, thereby switching the engaging member to an unlocked state. the first lower transmission part is provided to rotate integrally with a rotating member, and the second lower transmission part is provided to operate integrally with a locking member,
the fourth engagement portion is a pressure-receiving portion provided on the second lower transmission portion so that the locking member is switched to an unlocked state by application of a force in a predetermined pressure direction intersecting with the rotation axis of the rotation member,
The telescopic leg device of a ladder body as described in claim 13, characterized in that the third engagement portion is a pressure protrusion that is provided on the first lower transmission portion so as to protrude in a direction intersecting the rotation axis of the rotating member and engages with the pressure-receiving portion so as to apply a force in the pressure direction when the first lower transmission portion is rotated integrally with the rotating member. The ladder body telescopic leg device according to claim 14, characterized in that the remote control mechanism further has a lower holding part that rotatably holds the first lower transmission part. The ladder body telescopic leg device according to claim 15, characterized in that at least a portion of the lower holding portion is formed by a portion adjacent to the locking members of the left and right locking mechanisms of the ladder body. A ladder body having a plurality of rungs arranged in steps between two left and right posts, characterized in that the ladder body is equipped with an extendable leg device according to any one of claims 1 to 16.

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