JP7281122B2 - Ladder body lock structure and ladder body - Google Patents

Description

TECHNICAL FIELD The present invention relates to an extendable ladder body and its lock structure.

BACKGROUND Conventionally, ladders, stepladders, stepladders, tripods, scaffolds, and the like are known as lifting tools having a ladder body having a pair of struts and a tread bridged between the pair of struts. In such a ladder body, a technique is used in which a plurality of struts are connected in a nested manner and the consecutive struts are fixed in the extended position by a lock mechanism (see Patent Document 1, for example).

JP 2007-186898 A

In the ladder body described in Patent Literature 1, a lock mechanism having a lock pin (stopper pin) is provided on one of two continuous pillars. Then, when the struts are in the extended position, the lock pin is inserted into the other strut by the urging force of the coil spring to restrict the relative displacement of the struts.

In the ladder body constructed as described above, when a plurality of struts are used in the extended position, the lock pin may be gradually retracted toward the proximal end (in the direction of the coil spring) due to friction with the struts. That is, there is a possibility that the lock pin is displaced in the unlocking direction while the ladder is in use.

The present invention has been made in view of the circumstances as described above, and the problem to be solved by the present invention is that when a plurality of struts are used in the extended position, friction occurs between the lock pin and the struts. Another object of the present invention is to provide a ladder body locking mechanism capable of preventing a lock pin from being displaced in an unlocking direction, and a ladder body.

Means for solving the above problems will be described below.

A ladder body locking mechanism according to the present invention includes a plurality of ladder members each having a pair of cylindrically formed struts and a tread bridged between the pair of struts, and the struts are nested. A ladder body that can be extended and contracted by being connected to a ladder body, and a locking mechanism for the ladder body that fixes the continuous struts to each other at a predetermined position, wherein the locking mechanism is assembled to one strut a lock pin that is fixed to the tread and inserted into an insertion hole formed in the other post in a state in which the one post and the other post that is inserted into the one post are extended; a biasing means for displacing the pin to an insertion position by biasing the pin toward the distal end of the lock pin; and a retracted position on the proximal side of the lock pin against the biasing force of the biasing means. an unlocking portion that is displaced toward the As a result, the lock pin is displaced from the insertion position to the retracted position to release the fixation of the pillars, and the lock pin is moved from the insertion position to the retracted position by the unlocking portion positioned at the lock position. Displacement to the retracted position is restricted.

Further, in the ladder body locking mechanism according to the present invention, the lock pin has an engaging portion formed in an axially intermediate portion, an engaged portion is formed in the unlocking portion, and the lock pin When the unlocking portion is displaced from the locking position to the unlocking position when positioned at the insertion position, the locked portion and the locking portion do not engage and the lock pin moves to the retracted position. When the lock pin is displaced from the insertion position toward the retracted position when the lock release portion is positioned at the lock position, the locked portion engages with the locking portion. Thereby, the displacement of the lock pin to the retracted position is restricted.

Further, in the ladder body lock mechanism according to the present invention, when the lock pin is displaced from the insertion position toward the retracted position, the unlocking portion maintains the lock position by its own weight.

In the ladder body locking mechanism according to the present invention, the unlocking portion is biased toward the locked position by a biasing member, and when the lock pin is displaced from the inserted position toward the retracted position, and the unlocking portion maintains the locked position by the biasing force of the biasing member.

Further, the ladder body according to the present invention comprises a pair of cylindrically formed pillars, a tread bridged between the pair of pillars, and the continuous pillars provided on the treads. a lock mechanism for fixing at a predetermined position, and a plurality of ladder members that can be extended and contracted by connecting a plurality of the struts in a nested manner, wherein the lock mechanism is attached to one strut. a lock pin fixed to the assembled tread and inserted into an insertion hole formed in the other post in a state in which the one post and the other post inserted into the one post are extended; a biasing means for displacing the lock pin to the insertion position by biasing the lock pin toward the distal end of the lock pin; an unlocking portion displaceable toward a certain retracted position, the unlocking portion being displaceable between the locking position and the unlocking position, and the unlocking portion moving from the locked position to the unlocked position; , the lock pin is displaced from the insertion position to the retracted position to release the fixation of the pillars. A locked portion is formed in the unlocking portion, and when the unlocking portion is displaced from the locked position to the unlocked position when the lock pin is positioned at the insertion position, the locked portion and The lock pin is displaced to the retracted position without being engaged with the locking portion, and the lock pin is displaced from the insertion position toward the retracted position when the unlocking portion is positioned at the lock position. In this case, the engagement between the locked portion and the locking portion restricts the displacement of the lock pin to the retracted position.

According to the ladder body locking mechanism and the ladder body according to the present invention, even if friction occurs between the lock pin and the pillars when using the plurality of pillars in the extended position, the lock pin moves in the unlocking direction. There is an effect that it can be prevented from being displaced to.

The perspective view which shows the use condition of the ladder which concerns on one Embodiment. The perspective view which shows the contraction state of a ladder. FIG. 3 is an exploded perspective view showing a locking mechanism; (a) and (b) are respectively a front sectional view and a plan view showing the lock mechanism according to the first embodiment. (a) and (b) are front cross-sectional views and plan views, respectively, showing an initial state of rotation of the lock mechanism according to the first embodiment. (a) and (b) are front cross-sectional views and plan views, respectively, showing a post-rotational state of the lock mechanism according to the first embodiment. (a) and (b) are front cross-sectional views and plan views, respectively, showing a regulated state of the lock mechanism according to the first embodiment. (a) and (b) are respectively front cross-sectional views showing the lowermost locking mechanism. Front sectional drawing which shows the contraction|reduction method of a ladder. Front cross-sectional view showing the lock mechanism in a contracted state. (a) and (b) are respectively front cross-sectional view and plan view showing a lock mechanism according to a second embodiment. (a) and (b) are front sectional views and plan views, respectively, showing a lock mechanism according to a third embodiment. (a) and (b) are respectively front cross-sectional view and plan view showing a lock mechanism according to a fourth embodiment. (a) and (b) are front sectional views and plan views, respectively, showing a lock mechanism according to a fifth embodiment. (a) and (b) are front cross-sectional views and plan views, respectively, showing a lock mechanism according to a sixth embodiment.

[Ladder 1]
1 and 2, the schematic configuration of the ladder 1 employing the locking mechanism 20 and the lower locking mechanism 30, which are the locking mechanisms of the ladder body according to the present invention, will be described below. In this embodiment, the ladder 1 is described as an example of a ladder body. Also, the locking mechanism 20 and the lower locking mechanism 30 are the first embodiment of the locking mechanism according to the present invention. That is, the locking mechanism according to the present invention includes a ladder body in which a tread for the user to ascend and descend is bridged between a pair of pillars, and a plurality of pillars are connected in a nested manner. It is also possible to adopt other configurations such as stepladders, stepladders, tripods, scaffolds, and the like.

As shown in FIGS. 1 and 2, the ladder 1 according to the present embodiment includes a lower ladder member 10L forming the lowest portion of the ladder 1, and a plurality of (15 in this embodiment) forming the intermediate portion of the ladder 1. ) and a pair of upper struts 11U and 11U forming the top of the ladder 1 as main components.

As shown in FIGS. 1 and 2, the lower ladder member 10L is a pair of lower pillars 11L and 11L formed in the shape of a square tube and a tubular member bridged between the lower pillars 11L and 11L. Two lower treads 13L, 13L are provided. In the ladder 1 according to the present embodiment, the cross-sectional shape of the lower support 11L (the same applies to the support 11 and the upper support 11U, which will be described later) is formed into the same polygonal shape, thereby facilitating positioning for drilling. In addition, it restricts the relative rotation around the axis that occurs between it and the strut 11 connected to the upper side.

The lower treads 13L are fixed one by one to the upper end portion and the lower middle portion of the lower strut 11L. In this embodiment, the lower strut 11L and the lower rail 13L are made of a light metal material made of aluminum or an aluminum alloy (the strut 11, the upper strut 11U, and the rail 13, which will be described later, are also made of light metal). as well). Both ends of each lower tread 13L are fixed to the two lower pillars 11L, 11L by resin-made lower connecting members 12L. Grounding members 14, 14 made of resin are fixed to the lower ends of the lower struts 11L, 11L.

Between the lower struts 11L, 11L, lower locking mechanisms 30 are provided at both ends of the upper lower tread 13L (see FIG. 8). As shown in FIG. 8, an insertion hole 11a is opened inwardly (on the side of the adjacent lower support 11L) at the upper ends of the lower supports 11L. A lock pin 33 is inserted into the insertion hole 11a from a lower lock mechanism 30 provided outside the lower column 11L. As a result, the insertion portion 33b formed at the tip of the lock pin 33 extends inside the lower support column 11L.

As shown in FIG. 1, the ladder member 10 includes a pair of posts 11 formed in the shape of a square tube, and a tread 13, which is a tubular member that spans the upper ends of the posts 11.11. . Both ends of the tread 13 are fixed to the posts 11, 11 by resin connecting members 12, respectively. Specifically, as shown in FIGS. 3 and 4, the insertion tube portion 12a of the connecting member 12 is inserted into the tread 13. As shown in FIG. Further, the connecting member 12 is fixed to the supporting column 11 by tightening the fixing portion 12e with the screw S while the supporting column 11 is inserted inside the body portion of the connecting member 12 . As a result, the post 11 and the tread 13 are connected by the connecting member 12 . A total of four stopper members 16s are fixed at two upper and lower positions on the front surface and the rear surface of the outer peripheral surface of each of the struts 11 (see FIG. 9).

As shown in FIGS. 3 and 4, lock mechanisms 20 are provided at both ends of the tread 13 between the struts 11 and 11, respectively. An insertion hole 11a is opened in the upper end portion of each of the struts 11, 11 on the inner side (on the side of the adjacent strut 11). A lock pin 23 is inserted from a lock mechanism 20 provided outside the column 11 into the insertion hole 11a. As a result, an insertion portion 23b formed at the tip of the lock pin 23 extends inside the post 11. As shown in FIG. In addition, an insertion hole 11b is opened inwardly (on the side of the adjacent support 11) in the middle of the supports 11, specifically at the same height as the upper end of the upper stopper member 16s.

As shown in FIG. 1, the upper support 11U is a rod-shaped member forming the uppermost part of the ladder 1. As shown in FIG. The respective upper struts 11U, 11U are inserted into the struts 11, 11 of the ladder member 10 one step below. The upper end of the upper support 11U is covered with a cap member 15 made of resin.

As shown in FIGS. 1 and 2, in the ladder 1, the lower support 11L of the lower ladder member 10L, the support 11 of the plurality of ladder members 10, and the upper support 11U are connected in a nested manner. In other words, the ladder 1 is configured such that the upper struts (upper strut 11U and strut 11) are continuously stored inside the lower struts (strut 11 and lower strut 11L). Therefore, the post 11 of the ladder member 10 is configured such that the inner diameter gradually decreases from the bottom to the top.

As a result, the treads 13 that are bridged between the pillars 11 in each ladder member 10 are configured so that their length in the longitudinal direction (horizontal direction) gradually increases from the lower side to the upper side. there is In this way, the ladder 1 telescopes between the extended state shown in FIG. 1 and the shortened state shown in FIG. It is possible.

[Lock mechanism 20]
Next, the configuration of the lock mechanism 20 will be described in detail with reference to FIGS. 3 to 10. FIG. As shown in FIG. 9, the locking mechanism 20 is a mechanism for fixing the vertically continuous pillars 11 of the ladder 1 in the extended state to each other at a predetermined position (extended position).

As described above, the locking mechanisms 20 are provided at both ends of the treads 13 . Specifically, as shown in FIG. 4A, the lock mechanism 20 is accommodated inside the insertion tube portion 12a of the connecting member 12. As shown in FIG. In this embodiment, the lock mechanism 20 is composed of a spring support member 21 , a spring 22 , a lock pin 23 and an unlocking member 24 .

As shown in FIGS. 3 and 4(a), the spring support member 21 is fixed to the end of the insertion tube portion 12a in a state in which the spring 22, which is an urging means, is accommodated inside the tubular body, which is the main body portion. be done. A cylindrical lock pin 23 made of iron is housed in the tubular body of the spring support member 21 at its base end (the right end in FIG. 4A ) and abuts against the spring 22 . The spring 22 biases the lock pin 23 toward the tip side of the lock pin 23 (left side in FIG. 4(a)).

The urging force of the spring 22 causes the insertion portion 23b, which is the tip portion of the lock pin 23, to extend from the pin extension hole 12b of the connecting member 12. As shown in FIG. In this way, the lock pin 23 can move back and forth in the axial direction inside the insertion tube portion 12a against the biasing force of the spring 22. As shown in FIG. An engaged portion 23a having a smaller diameter than the circumference is formed in the middle portion of the lock pin 23. As shown in FIG. A front surface of the engaged portion 23a in the axial direction of the lock pin 23 is formed as a locking portion 23c. A position restricting portion 23d having a larger diameter than the periphery is formed on the side of the insertion portion 23b in the middle portion of the lock pin 23. As shown in FIG.

The lock pin 23 can be displaced to the base end side by the unlocking member 24 . The unlocking member 24 is formed including a rotating shaft 24a, an engaging portion 24b, an abutting portion 24c, a restricting portion 24d, and a locked portion 24e. The unlocking member 24 can swing up and down in the connecting member 12 by inserting the rotation shaft 24a into the first engaged recess 12c, which is a notch formed in the connecting member 12. As shown in FIG.

As shown in FIGS. 4A and 4B, the engaging portion 24b of the unlocking member 24 is inserted into the engaged portion 23a of the lock pin 23 and engages with the engaged portion 23a. As a result, the unlocking member 24 receives the biasing force of the spring 22 via the lock pin 23 and is biased downward. A contact portion 24c formed at the bottom of the unlocking member 24 receives the biasing force of the spring 22 and extends downward from the opening 13a formed at the bottom surface of the tread 13. As shown in FIG. In addition, a restricting portion 24d formed at the end of the unlocking member 24 abuts against the inner peripheral surface of the tread 13, thereby restricting the downward swinging motion of the unlocking member 24. As shown in FIG.

As described above, the lock pin 23 is urged forward by the biasing force of the spring 22, and the insertion portion 23b passes through the pin extension hole 12b of the connecting member 12 and the insertion hole 11a of the pillar 11 to the inside of the pillar 11. extended to The extension position of the lock pin 23 is restricted by the position restriction portion 23d coming into contact with the periphery of the pin extension hole 12b.

At this time, the strut 11 and the strut 11i inserted inside the strut 11 (hereinafter referred to as a "second strut") are in the extended position, and the insertion hole 11b in the second strut 11i is inserted into the strut 11. When it matches the insertion hole 11a, the insertion portion 23b of the lock pin 23 is inserted into the insertion hole 11b of the second strut 11i as shown in FIGS. 4(a) and 4(b). Thereby, the strut 11 and the second strut 11i are fixed to each other in the extended position.

That is, in the struts 11 that are connected to each other, the second strut 11i inserted inside is pulled up to the extended position, and the insertion hole 11b of the second strut 11i is aligned with the insertion hole 11a of the strut 11, The lock pin 23 is forcibly inserted into the insertion hole 11b by the biasing force of the spring 22, and the support 11 and the second support 11i are locked with each other. Hereinafter, this state shown in FIGS. 4A and 4B will be referred to as a "locked state", the position of the lock pin 23 in the locked state as the "insertion position", and the position of the unlocking member 24 in the locked state as the "locked position". and described.

At this time, as shown in FIG. 9, the stopper member 16i fixed to the outer peripheral surface of the second post 11i comes into contact with the connecting member 12 fixed to the post 11, thereby displacing the second post 11i at the extended position with respect to the post 11. Regulated. In other words, the user of the ladder 1 can place the second support 11i in the extended position with respect to the support 11 by pulling the second support 11i out of the support 11 until its displacement is restricted.

The user of the ladder 1 pulls up the struts 11 of the ladder member 10 in order from the top, starting with the upper strut 11U, when changing from the shortened state shown in FIG. 2 to the extended state. As a result, the posts 11 on the upper side are sequentially locked at the extended position, and finally the ladder 1 can be brought into the extended state.

The unlocking member 24 can displace the lock pin 23 toward the base end side against the biasing force of the spring 22 . Specifically, as indicated by an arrow R in FIGS. 4(a) and 5(a), when the unlocking member 24 receives a turning force from below, the unlocking member 24 moves upward (see FIG. 4 ( a) and clockwise in FIG. 5(a)). At this time, the engaged portion 24e of the unlocking member 24 is inserted inside the engaged portion 23a of the lock pin 23 as shown in FIGS. 5(a) and 5(b).

Further, as shown in FIGS. 6A and 6B, when the unlocking member 24 rotates further, the lock pin 23 resists the biasing force of the spring 22 by the force received from the engaging portion 24b of the unlocking member 24. and is displaced proximally. Hereinafter, this state shown in FIGS. 6A and 6B will be referred to as the "unlocked state", the position of the lock pin 23 in the unlocked state as the "retracted position", and the position of the unlocking member 24 in the unlocked state as the " “Unlocked position”.

Thus, when the lock pin 23 of the lock mechanism 20 is displaced to the retracted position on the base end side, the insertion portion 23b of the lock pin 23 is removed from the insertion hole 11b of the second support 11i as shown in FIG. The locked state with the second strut 11i is released. At this time, friction occurs between the lock pin 23 and the second support 11i, but since the support 11 is made of an aluminum-based material that is softer than the iron lock pin 23, the lock pin 23 wears out. never. By releasing the locked state of the second strut 11i with the ladder 1 standing on the ground, the second ladder member 10i including the second strut 11i descends by its own weight as indicated by the arrow D in FIG. .

Then, as shown in FIG. 10, the unlocking member 24i provided in the lock mechanism 20i of the second ladder member 10i abuts on the tread 13 of the ladder member 10, so that the second strut 11i and the second strut The locked state with the third strut 11s inserted in 11i is released. In this manner, the unlocking member 24 is configured to be actuated by contact with the tread 13 one step below the tread 13 having the unlocking member 24 . In this way, the ladder 1 in the extended state can be shortened by sequentially releasing the locked state of the pillars 11 from the lower side.

As described above, in the locking mechanism 20 according to the present embodiment, the unlocking member 24 has the locking position shown in FIGS. 4A and 4B and the unlocking position shown in FIGS. 6A and 6B. can be displaced between When the lock pin 23 is positioned at the insertion position, if the lock release member 24 is displaced from the lock position to the unlock position, the locked portion 24 e of the lock release member 24 is not engaged with the lock pin 23 . Since it is inserted inside the portion 23a, it does not engage with the engaging portion 23c. As a result, the lock pin 23 is displaced from the insertion position to the retracted position, and the fixing between the support columns 11 is released.

Further, in the lock mechanism 20 according to the present embodiment, the lock pin 23 is configured such that displacement from the insertion position to the retracted position is restricted by the unlocking member 24 located at the lock position. Specifically, when the unlocking member 24 is positioned at the locked position, a force is applied to the lock pin 23 as indicated by an arrow F in FIG. When displaced, the unlocking member 24 maintains the locked position by its own weight. Therefore, as shown in FIG. 7A, the locked portion 24e of the unlocking member 24 and the locking portion 23c of the lock pin 23 are engaged. As a result, the rotation of the unlocking member 24 is restricted, and at the same time, the displacement of the lock pin 23 to the retracted position is restricted.

As described above, according to the lock mechanism 20 according to the present embodiment, even if friction occurs between the lock pin 23 and the struts 11 when using the plurality of struts 11 in the extended position, the unlocking member Since the displacement of the lock pin 23 from the insertion position to the retracted position is restricted by 24, it is possible to prevent the lock pin 23 from being displaced in the unlocking direction.

Specifically, even if the lock pin 23 is displaced from the insertion position toward the retracted position when the unlocking member 24 is positioned at the lock position, the locked portion is not locked as shown in FIGS. Since the displacement of the lock pin 23 to the retracted position is restricted by the engagement between the lock pin 24e and the locking portion 23c, it is possible to prevent the lock pin 23 from being displaced in the unlocking direction. In this embodiment, the configuration of the lock mechanism 20 is simplified by configuring the unlocking member 24 to maintain the locked position by its own weight.

In the ladder 1 according to the present embodiment, the lock pin 23 is inserted into the insertion hole 11b on the outer peripheral surface of the lock pin 23 in the lock mechanism 20 (the same applies to the lock pin 33 in the lower lock mechanism 30 described later, and the same applies hereinafter). A tapered surface can be formed as a release restricting portion on the distal end side of the lock pin 23 from the abutment portion with which the inner peripheral surface of the insertion hole 11b abuts in the closed state.

Specifically, a tapered surface is formed on the tip end side of the lock pin 23 as an inclined surface so that the tip diameter increases along the axial direction of the lock pin 23 . The inner peripheral surface of the insertion hole 11b abuts on the tapered surface. By forming the tapered surface in this way, it is possible to make it difficult for the lock pin 23 to be removed from the insertion hole 11b.

[Lower lock mechanism 30]
Next, the configuration of the lower lock mechanism 30 provided on the lower ladder member 10L will be described with reference to FIGS. 8(a) and 8(b). The lower lock mechanism 30 is a mechanism for fixing the lower support 11L and the support 11 inserted into the lower support 11L in the extended state of the ladder 1 at a predetermined position (extended position).

As described above, the lower locking mechanisms 30 are provided at both ends of the lower tread 13L provided above the lower strut 11L. Specifically, as shown in FIG. 8(a), the lower lock mechanism 30 is accommodated inside the insertion tube portion 12a of the lower connecting member 12L. In this embodiment, the lower lock mechanism 30 is composed of a spring support member 31, a spring 32, a lock pin 33, and an unlock member .

As shown in FIGS. 8(a) and 8(b), the spring support member 31 accommodates a spring 32, which is a biasing means, in the tubular body, which is the main body, and is attached to the end of the insertion tubular portion 12a. Fixed. A cylindrical lock pin 33 made of iron is housed in the cylindrical body of the spring support member 31 at its base end (the right end in FIGS. 8A and 8B) and contacts the spring 32 . The spring 32 biases the lock pin 33 toward the tip side of the lock pin 33 (left side in FIGS. 8(a) and 8(b)). It should be noted that it is also possible to form the lock pin 23 in a prism shape.

The biasing force of the spring 32 causes the insertion portion 33b, which is the tip of the lock pin 33, to extend from the pin extension hole 12b of the lower connecting member 12L. In this way, the lock pin 33 can move back and forth in the axial direction inside the insertion tube portion 12 a against the biasing force of the spring 32 . An engaged portion 33a having a small diameter is formed in the middle portion of the lock pin 33 on the tip side. A locking portion 33c is formed on the surface of the lock pin 33 on the side of the engaged portion 33a in the axial direction. A position restricting portion 33d having a larger diameter than the periphery is formed near the insertion portion 33b in the middle portion of the lock pin 33. As shown in FIG.

The lock pin 33 can be displaced toward the proximal end by the unlocking member 34 . The unlocking member 34 is formed including a rotating shaft 34a, an engaging portion 34b, a hook portion 34c, a restricting portion 34d, and a locked portion 34e. The unlocking member 34 is inserted into the second engaged recess 12d (see FIG. 3), which is a notch formed in the lower connecting member 12L, so that the rotation shaft 34a is inserted into the lower connecting member 12L. It can swing up and down. The lock release member 34 is provided with a coil spring 35 as an urging member around the rotation shaft 34a. The coil spring 35 biases the unlocking member 34 toward the tip of the lock pin 33 (counterclockwise direction in FIG. 8A). Also, the restricting portion 34d formed at the upper end of the unlocking member 34 abuts against the inner peripheral surface of the lower tread 13L, thereby restricting the rocking of the unlocking member 34 to the tip side of the lock pin 33. . A hook portion 34c rotatably connected to the lower portion of the unlocking member 34 hangs down from an opening 13a formed in the lower surface of the lower tread 13L.

The engaging portion 34 b of the unlocking member 34 engages with the engaged portion 33 a of the lock pin 33 . As described above, the lock pin 33 is biased forward by the biasing force of the spring 32, and the insertion portion 33b extends downward from the pin extension hole 12b of the lower connecting member 12L and the insertion hole 11a of the lower support 11L. It extends inside the column 11L. At this time, the lower strut 11L and the strut (second strut) 11i inserted inside the lower strut 11L are in the extended position, and the insertion hole 11b of the second strut 11i is the insertion hole 11a of the strut 11. , the insertion portion 33b of the lock pin 33 is inserted into the insertion hole 11b of the second support 11i as shown in FIG. 8(a). The extending position of the lock pin 33 is restricted by the position restricting portion 33d coming into contact with the periphery of the pin extending hole 12b. Thereby, the lower strut 11L and the second strut 11i are fixed to each other in the extended position.

The unlocking member 34 can displace the lock pin 33 toward the base end side against the biasing force of the spring 32 . Specifically, when the hook portion 34c of the unlocking member 34 is pulled downward by the user, the unlocking member 34 rotates downward (clockwise in FIG. 8A). When the lock release member 34 rotates, the lock pin 33 is displaced toward the base end side against the biasing force of the spring 32 due to the force received from the engaging portion 34b of the lock release member 34 . At this time, the engaged portion 34 e of the unlocking member 34 is inserted into the engaged portion 33 a of the lock pin 33 . Furthermore, when the unlocking member 34 rotates further, the lock pin 33 is displaced toward the base end side against the biasing force of the spring 32 due to the force received from the engaging portion 34b of the unlocking member 34 .

As described above, also in the lock mechanism 30 according to the present embodiment, the unlocking member 34 can be displaced between the locked position and the unlocked position. When the lock release member 34 is displaced from the lock position to the unlock position when the lock pin 33 is positioned at the insertion position, the engaged portion 34 e of the lock release member 34 is the engaged portion of the lock pin 33 . Since it is inserted inside 33a, it does not engage with locking portion 33c. As a result, the lock pin 33 is displaced from the insertion position to the retracted position, and the fixing between the support columns 11 is released.

When the lock pin 33 of the unlocking member 34 is displaced to the base end side, the insertion portion 33b of the lock pin 33 is pulled out from the insertion hole 11b of the second support 11i, and the lower support 11L and the second support 11i are locked. is released. By unlocking the second strut 11i with the ladder 1 standing on the ground, the ladder member 10 connected to the lower ladder member 10L descends by gravity. In this way, by unlocking the lower support 11L positioned at the lowest stage, the locked state of the support 11 is released in order from the bottom, and the extended ladder 1 can be shortened. In other words, the user of the ladder 1 can automatically shorten the ladder 1 by manually releasing the lock on the lower ladder member 10L when the ladder 1 is in the extended state.

Further, in the lock mechanism 30 according to the present embodiment, the lock pin 33 is configured such that displacement from the insertion position to the retracted position is restricted by the unlocking member 34 located at the lock position. Specifically, if the lock pin 33 is displaced from the insertion position toward the retracted position when the lock release member 34 is at the lock position, the lock release member 34 maintains the lock position by the biasing force of the coil spring 35 . do. Therefore, as shown in FIG. 8B, the locked portion 34e of the unlocking member 34 and the locking portion 33c of the lock pin 33 are engaged. As a result, the rotation of the unlocking member 34 is restricted, and at the same time, the displacement of the lock pin 33 to the retracted position is restricted.

As described above, in the lock mechanism 30 as well, even if friction occurs between the lock pin 33 and the post 11 when the post 11 is in the extended position, the unlocking member 34 will move the lock pin 33 to the inserted position. to the retracted position, it is possible to prevent the lock pin 33 from being displaced in the unlocking direction.

Specifically, even when the lock pin 33 is displaced from the insertion position toward the retracted position when the unlocking member 34 is positioned at the lock position, as shown in FIG. Since the displacement of the lock pin 33 to the retracted position is restricted by the engagement with the portion 33c, it is possible to prevent the lock pin 33 from being displaced in the unlocking direction. In this embodiment, the unlocking member 34 is configured to maintain the locked position by the biasing force of the coil spring 35 at this time, so that the unlocking member 34 can maintain its posture against gravity.

[Another example]
Next, lock mechanisms 120 to 520 according to second to sixth embodiments will be described with reference to FIGS. 11 to 15. FIG. The lock mechanisms 120 to 520 according to other embodiments described below have substantially the same configuration as the lock mechanism 20 according to the first embodiment, so the parts different from the lock mechanism 20 (specifically, the lock pin and shape of the unlocking member).

As shown in FIGS. 11A and 11B, in the lock mechanism 120 according to the second embodiment, the lock pin 123 is prevented from being displaced from the insertion position to the retracted position by the unlocking member 124 positioned at the lock position. configured to be Specifically, an engaged portion 123a, which is a hole penetrating the lock pin 123 in the radial direction, is formed in the middle portion of the lock pin 123. As shown in FIG. A front surface of the engaged portion 123a in the axial direction of the lock pin 123 is formed as a locking portion 123c. Further, the unlocking member 124 includes a rotating shaft 124a, an engaging portion 124b inserted through the engaged portion 123a, a contact portion 124c, a restricting portion 124d, and a locked portion 124e. It is formed.

If the lock pin 123 is displaced from the insertion position toward the retracted position when the lock release member 124 is at the lock position, the lock release member 124 maintains the lock position by its own weight. Therefore, the locked portion 124e of the unlocking member 124 and the locking portion 123c of the lock pin 123 are engaged. As a result, the rotation of the unlocking member 124 is restricted, and at the same time, the displacement of the lock pin 123 to the retracted position is restricted.

As shown in FIGS. 12(a) and 12(b), in the lock mechanism 220 according to the third embodiment, the lock pin 223 is prevented from being displaced from the insertion position to the retracted position by the unlocking member 224 positioned at the lock position. configured to be Specifically, two large-diameter portions having a larger diameter than the lock pin 223 are formed in the middle portion of the lock pin 223 so as to be separated from each other in the axial direction, and the portion between the large-diameter portions is formed as an engaged portion 223a. It is A large-diameter portion of the lock pin 223 (on the left side in FIG. 12A) has a surface on the side of the engaged portion 223a that is formed as a locking portion 223c. Further, the unlocking member 224 includes a rotating shaft 224a, an engaging portion 224b inserted through the engaged portion 223a, a contact portion 224c, a restricting portion 224d, and a locked portion 224e. It is formed.

When the lock pin 223 is displaced from the insertion position toward the retracted position when the lock release member 224 is at the lock position, the lock release member 224 maintains the lock position by its own weight. Therefore, the locked portion 224e of the unlocking member 224 and the locking portion 223c of the lock pin 223 are engaged. As a result, the rotation of the unlocking member 224 is restricted, and at the same time, the displacement of the lock pin 223 to the retracted position is restricted.

As shown in FIGS. 13A and 13B, in the lock mechanism 320 according to the fourth embodiment, the lock pin 323 is prevented from being displaced from the insertion position to the retracted position by the unlocking member 324 positioned at the lock position. configured to be Specifically, engaged portions 323 a are formed by notching both side portions of the lock pin 323 in the middle portion of the lock pin 323 . A front surface of the engaged portion 323a in the axial direction of the lock pin 323 is formed as a locking portion 323c. The unlocking member 324 includes a rotating shaft 324a, an engaging portion 324b inserted into the engaged portion 323a, a contact portion 324c, a restricting portion 324d, and a locked portion 324e. It is formed.

If the lock pin 323 is displaced from the insertion position toward the retracted position when the lock release member 324 is positioned at the lock position, the lock release member 324 maintains the lock position by its own weight. Therefore, the locked portion 324e of the unlocking member 324 and the locking portion 323c of the lock pin 323 are engaged. As a result, the rotation of the unlocking member 324 is restricted, and at the same time, the displacement of the lock pin 323 to the retracted position is restricted.

As shown in FIGS. 14A and 14B, in the lock mechanism 420 according to the fifth embodiment, the lock pin 423 is prevented from being displaced from the insertion position to the retracted position by the unlocking member 424 positioned at the lock position. configured to be Specifically, an engaged portion 423a having a smaller diameter than the circumference is formed in the middle portion of the lock pin 423. As shown in FIG. A locking portion 423c having a slightly larger diameter than the engaged portion 423a is formed on the surface of the lock pin 423 on the front side of the engaged portion 423a in the axial direction. The unlocking member 424 includes a rotating shaft 424a, a cylindrical engaging portion 424b into which the engaged portion 423a is inserted, a contacting portion 424c, a restricting portion 424d, and a locking portion 423c. and a possible latched portion 424e.

If the lock pin 423 is displaced from the insertion position toward the retracted position when the lock release member 424 is at the lock position, the lock release member 424 maintains the lock position by its own weight. Therefore, the locking portion 423c of the lock pin 423 is inserted into the locked portion 424e of the unlocking member 424 and engaged with each other. As a result, the rotation of the unlocking member 424 is restricted, and at the same time, the displacement of the lock pin 423 to the retracted position is restricted.

As shown in FIGS. 15(a) and 15(b), in the lock mechanism 520 according to the sixth embodiment, the lock pin 523 is prevented from being displaced from the insertion position to the retracted position by the unlocking member 524 positioned at the lock position. configured to be Specifically, an engaged portion 523 a is formed in the middle of the lock pin 523 by cutting out about half of the lock pin 523 . A front surface of the engaged portion 523a in the axial direction of the lock pin 523 is formed as a locking portion 523c. The unlocking member 524 includes a rotating shaft 524a, an engaging portion 524b inserted into the engaged portion 523a, a contact portion 524c, a restricting portion 524d, and a locked portion 524e. It is formed.

When the lock pin 523 is displaced from the insertion position toward the retracted position when the lock release member 524 is at the lock position, the lock release member 524 maintains the lock position by its own weight. Therefore, the locked portion 524e of the unlocking member 524 and the locking portion 523c of the lock pin 523 are engaged. As a result, the rotation of the unlocking member 524 is restricted, and at the same time, the displacement of the lock pin 523 to the retracted position is restricted.

As described above, also in the lock mechanisms 120-520 according to the second to sixth embodiments, when the plurality of struts 11 are used in the extended position, there is friction between the lock pins 123-523 and the struts 11. Even if this occurs, the lock release members 124-524 restrict the displacement of the lock pins 123-523 from the insertion position to the retracted position. Thereby, it is possible to prevent the lock pins 123 to 523 from being displaced in the unlocking direction.

As shown in the above-described second to sixth embodiments, in the lock mechanism according to the present invention, the unlocking member located at the lock position regulates the displacement of the lock pin from the insertion position to the retracted position. Various configurations are possible. That is, the configuration for restricting the displacement of the lock pin is not limited in the present invention, and other configurations may be used.

1 ladder (ladder body) 10 ladder member
10L lower ladder member 11 strut
11a insertion hole 11b insertion hole
11i second strut 11s third strut
11U upper support 11L lower support
12 connecting member 12a insertion cylinder
12b pin extension hole 12c first engaged recess
12d Second engaged concave portion 12e Fixed portion
12L lower connecting member 13 tread
13a opening 13L lower tread
14 grounding member 15 cap member
16s stopper member 16U upper stopper member
20 locking mechanism (locking mechanism of the ladder body)
21 spring support member 22 spring
23 Lock pin 23a Engaged portion
23b insertion portion 23c locking portion
23d position restricting portion 24 unlocking member (unlocking portion)
24a rotation shaft 24b engaging portion
24c contact portion 24d restriction portion
24e engaged portion
30 lower locking mechanism (locking mechanism of ladder body)
31 spring support member 32 spring
33 Lock pin 33a Locked portion
33b insertion portion 33c locking portion
33d position control part
34 unlocking member (unlocking part)
34a Rotating shaft 34b Locking portion
34c hook portion 34d restricting portion
34e engaged portion 35 coil spring
S screw R rotation direction
M Displacement direction D Descent direction
120 lock mechanism (second embodiment)
123 Lock pin 123a Engaged portion
123c locking portion 124 unlocking member (unlocking portion)
124a Rotating shaft 124b Engagement part
124c contact portion 124d restriction portion
124e engaged portion
220 lock mechanism (third embodiment)
223 Lock pin 223a Engaged portion
223c locking portion 224 unlocking member (unlocking portion)
224a Rotating shaft 224b Engagement part
224c contact portion 224d restriction portion
224e locked portion
320 lock mechanism (fourth embodiment)
323 Lock pin 323a Engaged portion
323c locking portion 324 unlocking member (unlocking portion)
324a Rotating shaft 324b Engaging portion
324c contact portion 324d restriction portion
324e locked portion
420 lock mechanism (fifth embodiment)
423 Lock pin 423a Engaged portion
423c locking portion 424 unlocking member (unlocking portion)
424a Rotating shaft 424b Engagement part
424c contact portion 424d restriction portion
424e engaged portion
520 lock mechanism (sixth embodiment)
523 Lock pin 523a Engaged portion
523c locking portion 524 unlocking member (unlocking portion)
524a Rotating shaft 524b Engaging portion
524c contact portion 524d restriction portion
524e engaged portion

Claims (5)

A plurality of ladder members each having a pair of cylindrically formed pillars and a tread bridged between the pair of pillars are provided, and the pillars are telescopically connected to each other so as to be extendable. A ladder body locking mechanism for fixing the continuous struts to each other at a predetermined position in the ladder body,
The lock mechanism is fixed to the treads assembled to one strut, and is formed on the other strut when the one strut and the other strut inserted into the one strut are in an extended state. an urging means for urging the lock pin to the insertion position by urging the lock pin toward the distal end of the lock pin; a lock release portion that displaces the lock pin toward the retracted position that is the base end side of the lock pin,
The unlocking portion is displaceable between a locked position and an unlocked position,
Displacement of the lock release portion from the lock position to the unlock position displaces the lock pin from the insertion position to the retracted position, thereby releasing the fixation of the columns,
A locking mechanism for a ladder body, wherein the lock pin is restricted from being displaced from the inserted position to the retracted position by the unlocking portion positioned at the locked position. The lock pin has a locking portion formed in the middle in the axial direction,
A locked portion is formed in the unlocking portion,
When the unlocking portion is displaced from the locking position to the unlocking position when the lock pin is positioned at the insertion position, the locked portion and the locking portion do not engage and the lock pin is disengaged. is displaced to the retracted position,
When the lock pin is displaced from the insertion position toward the retracted position when the unlocking portion is positioned at the lock position, the engagement between the locked portion and the locking portion causes 2. The ladder body locking mechanism according to claim 1, wherein displacement of said lock pin to said retracted position is restricted. 3. The ladder body locking mechanism according to claim 1, wherein said unlocking portion maintains said locking position by its own weight when said locking pin is displaced from said inserted position toward said retracted position. the unlocking portion is biased toward the locked position by a biasing member;
3. The ladder according to claim 1, wherein when said lock pin is displaced from said inserted position toward said retracted position, said unlocking portion maintains said locked position by biasing force of said biasing member. body locking mechanism. a pair of pillars formed in a cylindrical shape, a tread bridged between the pair of pillars, a lock mechanism for fixing the continuous pillars provided on the treads to each other at a predetermined position; A ladder body that can be expanded and contracted by connecting a plurality of the struts in a nested manner, the ladder body comprising a plurality of ladder members comprising
The lock mechanism is fixed to the treads assembled to one strut, and is formed on the other strut when the one strut and the other strut inserted into the one strut are in an extended state. an urging means for urging the lock pin to the insertion position by urging the lock pin toward the distal end of the lock pin; a lock release portion that displaces the lock pin toward the retracted position that is the base end side of the lock pin,
The unlocking portion is displaceable between a locked position and an unlocked position,
Displacement of the lock release portion from the lock position to the unlock position displaces the lock pin from the insertion position to the retracted position, thereby releasing the fixation of the columns,
The lock pin has a locking portion formed in the middle in the axial direction,
A locked portion is formed in the unlocking portion,
When the unlocking portion is displaced from the locking position to the unlocking position when the lock pin is positioned at the insertion position, the locked portion and the locking portion do not engage and the lock pin is disengaged. is displaced to the retracted position,
When the lock pin is displaced from the insertion position toward the retracted position when the unlocking portion is positioned at the lock position, the engagement between the locked portion and the locking portion causes A ladder body in which displacement of the lock pin to the retracted position is restricted.

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