JP3893503B2 - Leg telescopic device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a leg expansion / contraction device for fixing a leg such as a stepladder, a ladder, a work table, or the like when the leg has a predetermined length.
[0002]
[Prior art]
Legs such as stepladders, ladders, work benches, etc. used on sloped ground, uneven ground, roofs, stairs, etc. are connected to the upper leg member, the lower leg member slidably fitted in the leg member, and the upper leg member. And a telescopic device that allows or prevents sliding of the lower leg member and expands and contracts the leg to a required length.
[0003]
As such a leg expansion / contraction device, conventionally, a rack provided on the lower leg member and teeth meshed with the rack are provided at the lower part and rotatably supported at the lower end part of the upper leg member at the upper part. A lock that includes a stopper, an elastic member that urges the stopper in a direction to mesh with the rack, and a slider that is supported by the upper leg member so as to be movable up and down, and the slider prevents the stopper from rotating in a direction away from the rack. It is known that it is movable to a position and an extension-side free position that is above this position and that allows this rotation and only allows the lower leg member to move to the extension side (special feature). (See Kaihei 8-158767).
[0004]
According to this leg expansion / contraction device, when locking the expansion / contraction of the leg, the slider is moved downward, and when it is free on the extension side, the slider is moved upward to move the extension side and the contraction side. In order to allow both, it is necessary to move the slider to the extension-side free position and manually rotate the stopper in a direction to remove it from the rack.
[0005]
[Problems to be solved by the invention]
The conventional leg expansion / contraction device has a problem that it is troublesome to allow both the movement of the lower leg member to the expansion side and the contraction side, and it is difficult to secure a space for installing the expansion / contraction device. It was. Further, since it is impossible to confirm from the outside whether the slider is in the locked position or in the extended side free position, there is a problem that the lower leg member in the extended side free state moves suddenly and is dangerous.
[0006]
An object of the present invention is to provide a leg expansion / contraction device that can be easily switched to a locked state, an expansion-side free state, or an expansion-side free state when extending or contracting a leg.
[0007]
Another object of the present invention is to provide a leg expansion / contraction device in which it is easy to secure a space for providing the expansion / contraction device.
[0008]
Still another object of the present invention is to provide a leg expansion / contraction device in which it can be confirmed from the outside whether it is in a locked state, an expansion side free state or an expansion both sides free state.
[0009]
[Means for Solving the Problems and Effects of the Invention]
The leg expansion / contraction device according to the present invention has a rack provided on a lower leg member slidably fitted in an upper leg member and teeth engaged with the rack in the lower part and the upper leg member in the upper part. A stopper rotatably supported at the lower end, an elastic member that is supported by the upper leg member and biases the stopper in a direction to mesh with the rack, and a slider that is supported by the upper leg member so as to be movable up and down. A locking position where the slider prevents the stopper from rotating in a direction away from the rack, an extension-side free position above this position and allowing this rotation, and a position further above this position, It is possible to switch to either one of the free positions on both sides of expansion and contraction that engages and rotates this in the direction away from the rack.
[0010]
According to the slider of the present invention, the stopper has teeth engaged with the rack and is rotatably supported by the upper leg member, so that the stopper can be rotated in the direction in which the teeth are detached from the rack. It is impossible to rotate the stopper in the direction in which the bite bites into the rack. And since the teeth are arranged at the lower part of the stopper and the rotation center is arranged at the upper part of the stopper, the movement of the lower leg member to the extending side is allowed to rotate, and this movement is allowed. For the movement of the lower leg member toward the contraction side, the stopper does not rotate and this movement is prevented. The elastic member urges the stopper in the direction of meshing with the rack. By applying a force larger than the elastic force of the elastic member, the stopper can be rotated in the direction away from the rack, and this force is released. Then, the stopper teeth engage with the rack. Therefore, when the slider is positioned at the free position on the extension side that allows the stopper to rotate away from the rack, the lower leg member can move to the expansion side, and the lower leg member cannot move to the contraction side. It becomes. Further, if the slider is positioned at a lock position that prevents the stopper from rotating in a direction away from the rack, not only the lower leg member moves to the contraction side, but also cannot move to the extension side. Further, when the slider is positioned at the free side of both the expansion and contraction that engages with the stopper and rotates it so as to be removed from the rack, the movement of the lower leg member to the expansion side and the contraction side is allowed. The movement of the slider to the free position on both sides of the expansion / contraction is obtained by applying a force larger than the elastic force of the elastic member to the slider. Rotates in the direction of meshing with the rack, and the slider returns to the free position on the extension side. Thus, the slider can be positioned at any one of the lock position, the extension-side free position, and the both-side expansion / contraction free position only by moving the slider up and down, and the operation at the time of extending / contracting the leg becomes easy.
[0011]
In this specification, the term “rack” means a flat plate or a bar-shaped or cylindrical member with teeth that are equidistantly spaced, and the shape of the teeth is, for example, a square cross section. It may be, and is not limited to the same shape as the teeth provided on the spur gear.
[0012]
A slider position restricting member that holds the slider in the locked position and elastically deforms to allow the movement when the slider is manually moved from the locked position to the extended free position or from the extended free position to the locked position. It is preferable. In this way, the slider in the lock position is prevented from moving upward by the slider position restricting member, and does not move to the extension side free position even if an object hits it. When the slider at the same position is pulled up by hand, the slider position restricting member is elastically deformed to allow the slider to move upward, and returns to its original shape after the slider moves upward. When the slider in the extension side free position is pulled down by hand, the slider position regulating member is elastically deformed to allow the slider to move downward, and returns to its original shape after the slider moves downward.
[0013]
The upper leg member has a substantially U-shaped cross section that opens to expose the rack, and is a horizontal section that is fixed to the upper leg member and opened in the same direction as the upper leg member. A bracket having a substantially U-shaped part is supported, a stopper is supported by a stopper support shaft that is passed between opposing walls of the U-shaped part of the bracket, and a slider is parallel to the stopper support shaft and from the stopper support shaft. It has a slide shaft that moves up and down at a position close to the opening of the U-shaped part of the bracket, a contact surface that contacts the slide shaft of the stopper when the slide shaft is at the lower end position, and a slide It is preferable that a concave surface is formed so that a predetermined gap is formed between the shaft when the shaft is at an upper and lower intermediate position. If it does in this way, the stopper, slider, and elastic member which constitute an expansion-contraction device will be stored compactly in the U-shaped part of a bracket. To fix the step rail to the upper leg member, place the stopper, slider and elastic member in the lower part of the U-shaped part of the support bracket, and insert and fix the end part of the step rail to the upper part of the U-shaped part of the bracket. As a result, the upper leg member and the foot cross are coupled to each other via the bracket. As a result, the members constituting the expansion / contraction device are supported by the brackets and arranged below the end of the tram, so that the expansion / contraction device does not protrude from the stepladder or the like, and there is a space for providing the expansion / contraction device. As a result, the connection between the upper leg member and the crosspiece becomes strong.
[0014]
According to the above-mentioned leg expansion / contraction device, the slider can be positioned at any one of the lock position, the expansion side free position, and the expansion both sides free position only by the vertical movement of the slider. And a display device that is fixed to the upper leg member and includes a fixing plate on which symbols indicating lock, extension side free and expansion and contraction both side free are written, By looking at the symbol, it is possible to confirm whether the slider is in the locked position, the extended side free position, or the extended both sides free position.
[0015]
The sliding plate with a window is made of a transparent synthetic resin, and an uneven surface for reflecting light from obliquely above is provided on the upper and lower portions of the window on either the front or back surface of the sliding plate. It is preferable. Such a concavo-convex surface can be obtained, for example, by continuously providing concave portions having a right-angled triangular cross section on the back surface of the slide plate so that the oblique sides are inclined obliquely upward from the back toward the front. The angle between the hypotenuse and the vertical line is about 15 ° to 30 °. In this way, light incident on the upper and lower parts of the slide plate from the upper side is refracted on the surface of the slide plate and is incident on the oblique side of the uneven surface at a large incident angle. To do. As a result, the refracted light is totally reflected at the oblique side portion of the uneven surface and cannot pass through the slide plate. Therefore, for example, when the display device is viewed obliquely from above during work on a stepladder, it can be confirmed through the transparent window whether the slider is in the locked position, the extended side free position, or the up and down free position. The light passing through the upper and lower portions of the window of the slide plate is reflected, and the symbols indicating the remaining two positions cannot be confirmed, so that the display of the slider position is not mistaken. In addition, when the display device is viewed from the front and close, the effect of the uneven surface is small, and all symbols indicating lock, extension side free and expansion side free can be confirmed through the slide plate, and the slider locks through the window. It can be confirmed whether the position, the extension-side free position, or the vertical free position is present, and the direction in which the slider should be moved can be easily identified.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
A case where the embodiment of the present invention is applied to a stepladder will be described below with reference to the drawings. In the following description, with respect to front / rear and left / right, the left and right in FIG. In addition, horizontal / vertical refers to the time when the legs are set up vertically.
[0017]
As shown in Fig. 1, the stepladder is assembled in a ladder shape by a pair of left and right legs (2), and a top plate (5) and a foot cross (6) secured between the left and right legs (2). Provided with a front and rear leg assembly (1). Although not shown in the figure, the front leg assembly (1) and the rear leg assembly (1) are connected so that the top plates (5) are rotatable with respect to each other. The leg assembly (1) can also be used as a ladder by rotating it 180 ° with respect to the front leg assembly (1).
[0018]
Each leg (2) has an upper leg member (3), a lower leg member (4) slidably fitted thereto, and a lower end of the lower leg member (4) via a joint (16). A disc-shaped anti-slip member (7) connected to the upper leg member (3) and a telescopic device (8) provided at the lower end of the upper leg member (3) are provided.
[0019]
The leg expansion / contraction device (8) consists of a lower leg member (4) that can slide both in the vertical direction and a free state on both sides of expansion and contraction. (4) can select one of the locked states that cannot slide in any of the up and down directions, and is in one of the expansion / contraction free state, the expansion side free state, or the locked state. It has a display device (9) for displaying.
[0020]
The upper leg member (3), the lower leg member (4), the top plate (5), and the step rail (6) are all made of aluminum alloy.
[0021]
2 to 11 show the left leg (2).
[0022]
As shown in FIG. 2, the second-tiered step rail (6) is fixed to the upper leg member (3) via the bracket (11). The upper leg member (3) has a U-shaped horizontal section that opens to the right, and the lower leg member (4) has a hollow shape with a substantially square horizontal section.
[0023]
The bracket (11) is an aluminum alloy shaped member having a substantially H-shaped horizontal cross section, and includes front and rear walls (12) and (13) and a connecting wall (14) that connects the middle of these. The outer method between the front and rear walls (12a) and (13a) in the left half and the inner method between the front and rear walls (12b) and (13b) in the right half are equal to the inner method between the front and rear walls of the upper leg member (3). Has been. Then, between the front and rear walls of the upper leg member (3), the front and rear walls (12a) and (13a) of the left half of the bracket (11) are inserted and fixed with rivets, and the front and rear of the right half of the bracket (11) The step rail (6) is inserted between the walls (12b) and (13b) and fixed with rivets, so that the step rail (6) and the upper leg member (3) are coupled. The lower leg member (4) has a cross-sectional shape that fits in a hollow portion formed by the upper leg member (3) and the bracket (11). Accordingly, the lower leg member (4) can be inserted to the vicinity of the upper end portion of the upper leg member (3) without interfering with the second-stage step rail (6) from the bottom. A reinforcing member (15) is obliquely held between the second-tiered step rail (6) and the lower end of the bracket (11) from the bottom.
[0024]
As shown in FIGS. 3 to 5, the leg expansion and contraction device (8) is provided on the right side wall of the lower leg member (4) with the rack (10) and the lower end of the upper leg member (3). A fixed horizontal section H-shaped bracket (21), a stopper support shaft (22) supported horizontally by the bracket (21), and a tooth (39) meshed with the rack (10) are provided at the bottom. The stopper (23), which is rotatably supported by the stopper support shaft (22) at the upper part, and the stopper (23) are urged so that the teeth (39) of the stopper (23) engage with the rack (10). Horizontal torsion coil spring (24) and horizontally supported by bracket (21) on the right side of stopper (23) so that it can move up and down, and can be positioned at either the free side of expansion or contraction, the free side of extension, or the lock position Slide shaft (25) and reverse U-shaped slide shaft moving handle that is attached to the slide shaft (25) and moves up and down with it A slider (20) consisting of (26), and a bracket (21) substantially L-shaped slide shaft position restricting member fixed to the lower end (27).
[0025]
The rack (10) is provided with teeth having a square cross section continuously up and down at a predetermined pitch. The dimensions of the teeth are, for example, a height of 1.3 mm, a width of 1.5 mm, and a pitch of 2 mm.
[0026]
The bracket (21) is a shape made of an aluminum alloy having a substantially H-shaped horizontal section, and includes front and rear walls (28) and (29) and a connecting wall (30) that connects the middle of these. The outer method between the front and rear walls (28a) and (29a) of the left half and the inner method between the front and rear walls (28b) and (29b) of the right half are equal to the inner method between the front and rear walls of the upper leg member (3). Has been. A U-shaped portion (31) opened rightward is formed by the front and rear walls (28b) (29b) and the connecting wall (30) in the right half. A rivet insertion hole (33) is provided in the upper half of the front and rear walls (28b) and (29b) of the U-shaped part (31), and the end of the bottom step (6) is U-shaped. The front and rear walls (28a) and (29a) of the left half of the bracket (21) are inserted between the front and rear walls of the upper leg member (3) and fixed with rivets. By being fixed, the lowermost step (6) and the upper leg member (3) are coupled. A circular stopper support shaft end insertion hole (34) is provided near the connecting wall (30) in the lower half of the front and rear walls (28b) and (29b) of the U-shaped part (31). A rectangular slide shaft guide hole (35) is provided. Both ends of the stopper support shaft (22) are fitted into the stopper support shaft end insertion hole (34), and both ends of the slide shaft (25) are fitted into the slide shaft guide hole (35). When the slide shaft (25) is in the upper end position, the axis of the slide shaft (25) is above the axis of the stopper support shaft (22), and when the slide shaft (25) is in the lower end position, the slide shaft The height of the stopper support shaft end insertion hole (34) is determined so that the axis of (25) is below the axis of the stopper support shaft (22).
[0027]
On the right edge portion of the front and rear walls (28b) and (29b) of the U-shaped portion (31), a protrusion (37) is provided so as to protrude forward and backward. Each protrusion (37) is provided with a groove (38) having a horizontal cross section that opens toward the opposing protrusion (37). The front and rear edges of the connecting wall of the bracket (21) are provided with a groove (32) having a C-shaped horizontal section that is a female thread portion into which a screw for attaching the slide shaft position restricting member (27) is screwed. .
[0028]
The stopper (23) includes a horizontal cylindrical part (40) through which the stopper support shaft (22) is inserted, and a block-like part (41) continuous below the horizontal cylindrical part (40). Teeth (39) are provided on the left side surface of the block-like portion (41) in total up and down at a predetermined interval.
[0029]
A square notch (36) is provided at the lower end of the connection wall (30) of the U-shaped part (31) of the bracket (21), and the rack (10) and stopper are passed through this notch (36). The teeth (39) of (23) are engaged.
[0030]
When the slide shaft (25) is in the upper end position, the upper end of the horizontal cylindrical portion (40) of the stopper (23) is engaged with the stopper (23) so that the teeth (39) are removed from the rack. A lever portion (42) that pivots in the direction is provided in a right-hand protruding shape. Further, the right side surface of the block-like portion (41) has a contact surface (43) formed so as to contact the slide shaft (25) when the slide shaft (25) is at the lower end position, and the slide shaft (25) And a concave surface (44) formed so as to have a predetermined gap therebetween when in the intermediate position. Thus, when the slide shaft (25) is at the lower end position, the stopper (23) is prevented from rotating in the direction in which the teeth (39) are removed from the rack, and when the slide shaft (25) is at the upper and lower intermediate positions. The stopper (23) is allowed to rotate in the direction in which the teeth (39) are removed from the rack. In this way, the upper end position, the intermediate position, and the lower end position of the slide shaft (25) correspond to the both-side free state, the extended side free state, and the locked state of the leg (2).
[0031]
Both ends of the torsion coil spring (24) are wound around the ends of the stopper support shaft (22), and the ends are brought into contact with the connecting wall (30) of the U-shaped portion (31) of the bracket (21). The central portion has an inverted U shape, and the top portion (24a) of the inverted U shape portion is brought into contact with the lever portion (42) of the stopper (23) from above. Thereby, the stopper (23) is urged in a direction in which the lever portion (42) is pushed down, that is, in a direction in which the teeth (39) engage with the rack (10).
[0032]
The slide shaft moving handle (26) is made of synthetic resin, and the front and rear walls (26a) (26a) that sandwich the front and rear walls (28b) and (29b) of the U-shaped part (31) of the bracket (21) from both front and rear sides. 26b) and a top wall (26c) that comes into contact with the upper end of the bracket (21) from above when the slider (20) is in the lower end position. The slide shaft (25) has a head (45) with a cross hole and a male screw end (46) .The front wall (26a) of the handle (26) has a head of the slide shaft (25). A through-hole (48) having a counterbore for accommodating the portion (45) is provided, and a through-hole (49) through which the male screw portion (46) of the slide shaft (25) is inserted is formed in the rear wall (26b). Is provided. The front and rear walls (26a) and (26b) of the handle (26) are further provided with ridges (on the right edge of the front and rear walls (28b) and (29b) of the U-shaped portion (31) of the bracket (21)). 37) and a groove (51) extending vertically to avoid interference with the end of the stopper support shaft (22) are provided. Then, the slide shaft (25) has a through-hole (48) with a counterbore in the front wall (26a) of the handle (26), and the front and rear walls (28b) (29b) of the U-shaped part (31) of the bracket (21). The slide shaft guide hole (35) and the handle (26) are inserted into the through hole (49) in the rear wall (26b), and the nut (47) is screwed into the male screw portion (46) of the tip. As a result, the slider (20) including the slide shaft (25) and the handle (26) is supported by the bracket (21) so as to be movable up and down, and the slide shaft (25) is moved up and down by moving the handle (26) up and down. Moving.
[0033]
The slide shaft position restricting member (27) is made of synthetic resin, and includes a horizontal wall (52) and a vertical wall (53) connected to the right edge thereof. The horizontal wall (52) has a through hole (54) having a shape corresponding to the cross-sectional shape of the lower leg member (4). The vertical wall (53) has a projecting edge (55) having a horizontal cross section that is fitted in a groove (38) provided in the protrusion (37) on the right edge of the bracket (21). Yes. A substantially rectangular notch (56) is provided at the center of the vertical wall (53), and an elastic deformation part (57) extending downward is provided at the upper edge of the notch (56). The elastically deformable portion (57) has a substantially vertical cross section bent to the left at the middle, a circular arc convex to the right of the vertical section above the bent position, and the left of the vertical section below the bent position. Curved in a convex arc shape. The elastic deformation portion (57) is provided integrally when the slide shaft position restricting member (27) is molded, and is thin plate-like and thus has elasticity. As will be described later, the elastic deformation portion (57) suppresses the movement of the slide shaft (25) from the stretch-side free state to the locked state and vice versa due to its elasticity. The lower end of the lower leg member (4) is fitted into the through hole (54) of the horizontal wall (52), and the protruding edge (55) of the vertical wall (53) is the ridge on the right edge of the bracket (21). The slide shaft position is controlled by screwing into the groove (32) with the screw hole provided in the bracket (21) from the lower side of the horizontal wall (52). The member (27) is fixed to the bracket (21).
[0034]
In the leg expansion / contraction device (8), the stopper support shaft (22), the stopper (23), the torsion coil spring (24) and the slide shaft (25) constituting the leg extension device (8) are formed in a U-shaped portion ( The handle (26) and the slide shaft position restricting member (27) are attached to the bracket (21) so as to cover the bracket (21). The bracket (21) also serves as a member for coupling the upper leg member (3) and the step rail (6). Therefore, an increase in the space accompanying installation of the leg expansion / contraction device (8) is small, and the leg expansion / contraction device (8) can be compactly arranged at the lower end of the upper leg member (3).
[0035]
As shown in FIGS. 5 to 7, the display device (9) for displaying the free or locked state includes a fixing plate (58) with a display label (61) fixed to the upper leg member (3), and a fixed state. The slide plate (59) is slidably attached to the surface of the plate (58), and the cap (60) is fixed to the upper end of the fixed plate (58).
[0036]
On the display label (61), the characters “upper and lower free (61a)”, “extension side free (61b)” and “lock (61c)” are displayed in this order from the top. The top and bottom free (61a) is displayed in white on the red background, the free extension (61b) is displayed in black on the yellow background, and the lock (61c) is displayed in white on the blue background. Accordingly, it is possible to identify which state is in the vicinity from the character and the color of the ground, and from the distance from the ground color.
[0037]
The fixing plate (58) has a pair of front and rear protruding wall portions (62) protruding leftward, which are inserted between the front and rear walls of the upper leg member (3) and fixed by rivets.
[0038]
Protruding portions (64) with a horizontal cross section are provided on both side edges of the slide plate (59), and guide grooves (63) for guiding the protruding portions (64) are provided on the fixed plate (58). ing. A step portion (63a) that restricts the downward movement of the slide plate (59) is provided at the lower end portion of the guide groove (63). The lower end portion of the slide plate (59) is provided with three rectangular fitting holes (65), and these fitting holes (65) are provided with 3 provided on the handle (26) of the slider (20). Two projections (58) are fitted in each. Thereby, the slide plate (59) is moved up and down with respect to the fixed plate (58) as the handle (26) moves up and down. The upward movement of the slide plate (59) is restricted by the cap (60).
[0039]
The slide plate (59) is made of a transparent synthetic resin, and the symbols (61a) (61b) (61c) of the display label (61) indicating the current position of the slider (20) are read in the upper and lower intermediate portions. A window (66) is provided. This window (66) is formed by making both the front and back surfaces of a transparent synthetic resin plate flat, and the surface (66a) of the window (66) protrudes to the right as it goes upward. The back surface (66b) of the window (66) is a vertical flat surface. An uneven surface (67) is formed on the back surface of the upper portion (59a) and the lower portion (59b) of the slide plate (59) from the window (66). As shown in FIG. 7, the concave and convex surface (67) is formed by continuously providing concave portions having a right-angled triangular cross section so that the oblique side portion (67a) is inclined obliquely upward from the back to the front. Is formed. For example, the width of the opening is 1 mm, the depth is 0.5 mm, and the angle between the hypotenuse (67a) and the vertical line is about 15 ° to 30 °.
[0040]
As shown in FIG. 7, when the display label (61) is viewed through the window (66) from diagonally above indicated by A, the light passing through the window (66) is refracted by the surface (66a). Since (66a) is a flat surface, the ground color of the display label (61) is clearly visible. In addition, since the surface (66a) is inclined so that it protrudes to the right as it goes up, the refracted light is almost horizontal compared to the surface with a vertical flat surface, which is almost the same as when viewed from the horizontal. looks like. That is, there is no possibility that the display symbol of the lock (61c) can be seen when viewed from obliquely above even though the extension side free (61b) is displayed. On the other hand, the light incident obliquely from above the upper part (59a) and the lower part (59b) of the window (66) of the slide plate (59) is refracted on the surface of the slide plate (59) and is uneven. Incident at a large incident angle to the hypotenuse (67a) of the surface (67). As a result, the refracted light is totally reflected by the oblique side portion (67a) of the uneven surface (67) and cannot pass through the slide plate (59). Therefore, for example, when the display device (9) is viewed obliquely from above during work on a stepladder, the slider (20) is placed in the locked position, the extended side free position, and the up and down free position through the transparent window (66). It is possible to confirm which is present, but the upper and lower portions (59a) and (59b) of the slide plate (59) from the window (66) only appear white, and display labels (61 ) Cannot be confirmed, and the display of the position of the slider (20) will not be mistaken.
[0041]
Also, when the display device (9) is viewed from the front and close, the uneven surface (67) is less affected, and all the symbols indicating lock, free extension and free both sides of expansion are confirmed through the slide plate (59). In addition, it can be confirmed whether the slider (20) is in the locked position, the extension side free position or the vertical free position through the window (66), and it is easy to determine which direction the slider (20) should be moved. Can be identified.
[0042]
The concave and convex surface (67) of the slide plate (59) may be provided on the surface, and the vertical cross section of the concave portion is not limited to the above, and is confirmed when viewed from the front. Although it is possible, various changes can be made within a range in which it is difficult to transmit light from obliquely above.
[0043]
Next, each of the expansion side free state, the both side free state, and the locked state of the expansion / contraction device (8) will be described with reference to FIGS.
[0044]
FIG. 8 shows the stretch-side free state. In this state, the slide shaft (25) is located in the middle of the vertically long slide shaft guide hole (35), and is a portion above the bending position of the elastic deformation portion (57) of the slide shaft position restricting member (27). It is received by. Since the stopper (20) has teeth (39) meshed with the rack (10) at the lower part and is supported by the upper leg member (3) at the upper part, the stopper (20) is stopped from the center of the stopper support shaft (22). The line toward the tooth (39) of (23) is inclined downward from the horizontal. Therefore, for the movement of the lower leg member (4) to the extending side, the stopper (23) rotates and this movement is allowed. Therefore, if the lower leg member (4) is pulled downward with a force larger than the elastic force of the torsion coil spring (24), as shown in the figure, the teeth (39) are stopped in the direction away from the rack (10) ( 23) rotates, and the lower leg member (4) can be pulled out downward. If the operation of pulling out the lower leg member (4) is stopped, the teeth (39) of the stopper (23) are engaged with the rack (10) by the elastic force of the torsion coil spring (24). Since the stopper (23) cannot be rotated in the direction in which the teeth (39) bite into the rack (10), the stopper (23) does not move against the contraction side of the lower leg member (4). This movement is prevented without rotating. Therefore, even when trying to move the lower leg member (4) upward, i.e., when a person gets on the top (6) or the top plate (5) in the free state of the extension side, the leg ( 2) will not shrink.
[0045]
FIG. 9 shows a state in which both the expansion and contraction are free. In this state, the handle (26) is moved upward by hand against the elastic force of the torsion coil spring (24) from the free extension state, and the slide shaft (25) is moved to the upper end of the slide shaft guide hole (35). Obtained by positioning. Thereby, the lever part (42) of the stopper (23) is pushed up by the slide shaft (25), and the teeth (39) of the stopper (23) are detached from the rack (10). Therefore, the lower leg member (4) can move both vertically. Therefore, with the stepladder upright, hold the handle (26) with one hand, hold the upper leg member (3) with the other hand, and place the upper leg member (3) against the lower leg member (4). The leg (2) can be shortened by moving it downward. When the hands are released in the free state on both sides of expansion and contraction, the slide shaft (25) is pushed down by the elastic force of the torsion coil spring (24), and returns to the free state on the expansion side.
[0046]
FIG. 10 shows a locked state. This state can be obtained by moving the handle (26) downward from the extended free state and positioning the slide shaft (25) at the lower end of the slide shaft guide hole (35). During the downward movement of the slide shaft (25), the elastically deforming portion (57) of the slide shaft position restricting member (27) is once moved to the right, and the slide shaft (25) is moved to the slide shaft guide hole ( It will return to its original position when it reaches the lower end of 35). Thereby, the upward movement of the slide shaft (25) is suppressed by the elastic deformation part (57). Therefore, even if an object hits, the slide shaft (25) does not move to the extension side free position. Then, the slide shaft (25) is engaged with the contact surface (43) on the right side surface of the stopper (23), and the rotation of the stopper (23) in the direction away from the rack (10) is prevented. Therefore, it is not possible to move the lower leg member (4) not only to the contraction side but also to the extension side. When the handle (26) is moved upward from the locked state by hand, the slide shaft (25) is once moved to the right by the elastic deformation portion (57), and the slide shaft (25) is moved to the slide shaft guide hole ( 35) When it reaches the middle, it returns to its original position, and the telescopic device (8) returns to the free state on the extension side.
[0047]
According to the leg expansion / contraction device (8), as described above, the slider (20) can be positioned at any one of the locked position, the expansion side free position, and the expansion side free position only by moving the slider (20) up and down. Therefore, the operation when the leg (2) is extended and contracted is extremely easy.
[0048]
FIGS. 11 to 13 show details of the anti-slip member joint (16) provided between the lower leg member (4) and the anti-slip member (7).
[0049]
As shown in the figure, the anti-slip member (7) includes a disc-shaped main body (71) made of synthetic resin, a concave fitting portion (72) integrally provided on the upper surface of the main body and having a spherical inner surface, and a main body. (71) A rubber bottom (73) provided on the lower surface. Further, a lower end cover (74) for closing the lower end opening of the lower leg member (4) is provided at the lower end portion of the lower leg member (4). The lower end cover (74) is made of synthetic resin, and is inserted into the lower end of the lower leg member (4) and is fixed to the lower leg member (4) with bolts and nuts. 75), a flange portion (76) provided at the lower end of the lower leg member (4) to close the lower end opening, a columnar downward projecting portion (77) provided on the lower surface of the flange portion (76), and a downward projecting portion. It further comprises a spherical convex fitting part (78) that continues to the lower end of (77).
[0050]
The anti-slip member joint portion (16) includes a concave fitting portion (72), a convex fitting portion (78) fitted therein, and a support shaft provided on the convex fitting portion (78). The support shaft (83) extending from side to side inserted into the support shaft end fitting hole (79) that is loosely inserted into the insertion hole (82) and both ends are provided in the concave fitting portion (72), and the concave fitting A compression coil spring (84) that is fitted in a recess (81) provided on the bottom surface of the portion (72) and biases the convex fitting portion (78) upward.
[0051]
The outer peripheral surface of the concave fitting portion (72) is cylindrical, and the peripheral wall of the concave fitting portion (72) opens upward at a position shifted by 90 ° from the support shaft end fitting hole (79). A notch (80) is provided.
[0052]
The support shaft (83) is formed of a spring pin, and both ends thereof are tightly fitted into the support shaft end insertion holes (79) of the concave fitting portion (72). Thereby, the concave fitting part (72) can be rotated back and forth around the axis of the support shaft (83), that is, the axis extending to the left and right with respect to the convex fitting part (78). The notch (80) on the peripheral wall of the concave fitting part (72) prevents the cylindrical lower protrusion (77) of the lower end cover (74) from interfering with the peripheral wall of the concave fitting part (72) during this rotation. The concave fitting part (72) is formed and can be rotated by 90 ° in the front-rear direction with respect to the convex fitting part (78).
[0053]
The support shaft insertion hole (82) of the convex fitting portion (78) has a diameter at the center of its length equal to the diameter of the support shaft (83) and is vertically moved from the center of the length toward each end. It is formed to spread in the direction. That is, as shown in FIG. 13, the cross-sectional shape of the support shaft insertion hole (82) viewed from the front side is shaped like a sector having a central angle of 60 ° facing each other in a symmetrical manner. A space that allows the support shaft (83) to turn left and right by 30 ° with respect to the convex fitting portion (78) about the axis passing through the center of the shaft (83) and extending in the front-rear direction ( S) is formed in the support shaft insertion hole (82).
[0054]
Since the joint portion (16) is configured as described above, the anti-slip member (7) is moved in the front-rear direction until the ground contact surface is parallel to the length direction of the lower leg member (4). Each can be rotated by 90 ° (see FIG. 12), and further, 30 ° in the left-right direction with respect to the horizontal axis extending back and forth from the state where the ground contact surface is perpendicular to the length direction of the lower leg member (4). It can be rotated one by one. Therefore, even if the place where the stepladder is installed is a surface inclined forward and backward or a surface inclined right and left, the anti-slip member (7) contacts the ground exactly. Further, since the compression coil spring (84) biases the convex fitting part (78) upward, the outer peripheral surface of the convex fitting part (78) and the bottom surface of the concave fitting part (72) The frictional force between them is reduced, and the anti-slip member (7) rotates smoothly both in the front-rear direction and in the left-right direction.
[Brief description of the drawings]
FIG. 1 is a front view schematically showing an example of a stepladder provided with a leg telescopic device according to the present invention.
2 is a cross-sectional view taken along the line II-II in FIG.
FIG. 3 is an exploded perspective view showing a leg telescopic device.
4 is a cross-sectional view taken along line IV-IV in FIG.
5 is a cross-sectional view taken along line VV in FIG.
FIG. 6 is an exploded perspective view of a display device showing a free or locked state of leg expansion and contraction.
FIG. 7 is an enlarged sectional view seen from the front side.
FIG. 8 is a vertical cross-sectional view showing an extension-side free state of the leg extension device.
FIG. 9 is a vertical sectional view showing the stretchable both sides free state.
FIG. 10 is a vertical sectional view showing the same telescopic both-side locked state.
FIG. 11 is an exploded perspective view showing a configuration of a lower end portion of a leg.
FIG. 12 is a cross-sectional view seen from the right side.
FIG. 13 is a cross-sectional view seen from the front side.
[Explanation of symbols]
(2) Leg
(3) Upper leg member
(4) Lower leg member
(8) Leg telescopic device
(9) Display device
(10) Rack
(20) Slider
(21) Bracket
(22) Stopper support shaft
(23) Stopper
(24) Torsion coil spring
(25) Slide shaft
(26) Slide axis moving handle
(27) Slide shaft position restricting member
(58) Fixed plate
(59) Slide board
(31) U-shaped part
(39) Teeth
(43) Contact surface
(44) Concave
(61a) (61b) (61c) Symbol
(66) Windows
(67) Uneven surface

Claims (5)

A rack (10) provided on a lower leg member (4) slidably fitted on the upper leg member (3) and a tooth (39) meshed with the rack (10) at the bottom A stopper (23) is rotatably supported at the lower end of the upper leg member (3) at the upper part, and a stopper (23) is attached in the direction supported by the upper leg member (3) and meshed with the rack (10). And a slider (20) supported by the upper leg member (3) so as to be movable up and down.The slider (20) is provided with a stopper ( 23) is locked to prevent the rotation, the free position on the extension side that allows this rotation and further above this position, and engages with the stopper (23) to engage the rack (10 The leg expansion / contraction device can be switched to one of the free positions on both sides of the expansion / contraction to be rotated so as to be disengaged. While holding the slider (20) in the locked position, when the slider (20) is manually moved from the locked position to the extended free position or from the extended free position to the locked position, the slider (20) is elastically deformed and allowed to move. The leg telescopic device according to claim 1, further comprising a slider position regulating member (27). The upper leg member (3) has a substantially U-shaped cross section that opens to expose the rack (10), and is fixed to the upper leg member (3) to the upper leg member (3). And a bracket (21) having a substantially U-shaped portion (31) with a horizontal cross section that opens in the same direction as the upper leg member (3) is supported, and the stopper (23) is a U-shaped portion (31) of the bracket (21). ) Is supported by the stopper support shaft (22) passed between the opposing walls, and the slider (20) is parallel to the stopper support shaft (22) and the U-shaped portion (31) of the U-shaped portion (31) from the stopper support shaft (22). It has a slide shaft (25) that moves up and down at a position close to the opening, and contacts the surface of the stopper (23) facing the slide shaft (25) when the slide shaft (25) is at the lower end position. 3. The leg telescopic device according to claim 1 or 2, wherein a contact surface (43) and a concave surface (44) that forms a predetermined gap between the slide shaft (25) when the slide shaft (25) is in an upper and lower intermediate position are formed. . Slide plate (59) with window (66) that moves up and down together with slider (20), and symbols (61a) (61b) (61c) fixed to upper leg member (3) and indicating lock, extension side free, and expansion both sides free ) And a display device (9) composed of a fixed plate (58) and a symbol (61a) (61b) (61c) of the fixed plate (58) from the window (66) of the slide plate (59). ), It is possible to confirm whether the slider (20) is in the locked position, the extended-side free position, or the telescopic both-side free position. Telescopic device. The slide plate (59) is made of a transparent synthetic resin, and obliquely above the upper portion (29a) and the lower portion (29b) of the window (66) on either side of the slide plate (59). The leg expansion / contraction device according to claim 4, further comprising an uneven surface (67) for reflecting light from the surface.

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