JP7489010B2 - Ladder/stepladder - Google Patents

Description

The present invention relates to a stepladder that can also be used as a ladder, and more specifically, to a mechanism for preventing a stepladder from opening.

Conventionally, ladder-cum-stepladders have been used that function as both a stepladder and a ladder by rotatably connecting the ends of a pair of ladder bodies (see, for example, Patent Document 1). In such ladder-cum-stepladders, a mechanism for preventing the ladder bodies from moving relative to each other in the ladder or stepladder state is used, which is provided between the posts that make up the pair of ladder bodies. In the case of the ladder-cum-stepladder described in Patent Document 1, the mechanism for preventing the ladder bodies from moving relative to each other in the ladder or stepladder state can be released by operating the mechanism for preventing the ladder bodies from moving relative to each other in the stepladder state, and the ladder-cum-stepladder can be folded up and closed.

On the other hand, there is a stepladder that can be folded and closed by operating an opening prevention mechanism provided between the ladder bodies that make up the stepladder (see, for example, Patent Document 2). In such a stepladder, the user can bring the pair of ladder bodies close to each other and close the stepladder by lifting the operating part of the opening prevention mechanism between the ladder bodies.

JP 2016-33305 A JP 2013-119745 A

According to the ladder-cum-stepladder described in Patent Document 1, an opening prevention mechanism is connected to each of the two posts that make up one of the ladder bodies. Therefore, when changing from the ladder state to the closed state, the user of the ladder-cum-stepladder needs to use both hands to operate the two opening prevention mechanisms, or to operate each opening prevention mechanism with one hand. For this reason, in situations where it is difficult for the user to use both hands, such as when holding tools, it is not easy to change from the ladder state to the closed state.

On the other hand, with the stepladder described in Patent Document 2, the user can switch from the stepladder state to the closed state simply by lifting the operating part with one hand. However, with this configuration in which a pair of ladder bodies are connected with an opening and stopping mechanism, the connection between either ladder body and the opening and stopping mechanism cannot be released, so the ladder state cannot be achieved. In addition, a separate structure must be provided to regulate the relative positions of the ladder bodies in the ladder state. For this reason, the configuration in which a pair of ladder bodies are connected with an opening and stopping mechanism, like the stepladder described in Patent Document 2, could not be adopted for a stepladder that also serves as a ladder.

The present invention was made in consideration of the above situation, and the problem that the present invention aims to solve is to provide a stepladder that can be easily changed from the stepladder state to the closed state.

Below, we explain the means to solve the above problems.

The stepladder/ladder combination of the present invention comprises a pair of ladder bodies each having two posts, a number of rungs stretched between the two posts, and a top plate connecting one ends of the two posts, the one ends of the ladder bodies being connected to each other so as to be rotatable relative to each other, and the ladder/ladder combination of the present invention is transformable into a closed state in which the pair of ladder bodies are close to each other, a stepladder state in which the pair of ladder bodies are spaced a predetermined distance apart, and a ladder state in which the pair of ladder bodies are opened 180 degrees, the stepladder/ladder combination of the present invention comprises an opening stop mechanism that restricts relative displacement of the pair of ladder bodies in each of the stepladder state and the ladder state, the opening stop mechanism comprises a restriction release member that releases the restriction on relative displacement of the pair of ladder bodies when in the stepladder state , the opening stop mechanism is rotatably supported on one of the posts of the pair of ladder bodies that face each other and are spaced apart from each other, and the opening stop mechanism is operable to rotate between the stepladder state and the ladder state. the arm member comprises at least one set of arm members each having a first arm body rotatably supported on one side of the support and a second arm body rotatably connected to a tip end of the first arm body and having a tip end engageable with the other side of the support, and in the step-ladder state, a rotary connection portion between the first arm body and the second arm body in the arm member is positioned lower than both ends of the arm body and is restricted from displacing downward from that position, and in the step-ladder state, the rotary connection portion is displaced upward to bend the arm members, thereby bringing the pair of ladder bodies into a closed state in close proximity, and in the step-ladder state, the restriction release member is displaced to rotate either the first arm body or the second arm body upward to bend the arm members .

In addition, in the ladder/stepladder of the present invention , the deregulation member is formed with an engagement portion that is positioned adjacent to the arm member when in the stepladder state, and an operating portion that is positioned adjacent to the rung or the top plate when in the stepladder state, and it is preferable that by displacing the operating portion of the deregulation member when in the stepladder state, the engagement portion is displaced, and the engagement portion rotates either the first arm body or the second arm body upwardly to bend the arm member .

In addition, in the ladder/stepladder of the present invention, it is preferable that the engagement portion is positioned below the arm member when in the stepladder state, the operating portion is positioned along the longitudinal direction of the step or the top plate on the underside close to the step or the top plate when in the stepladder state, and the release member is formed with a linking portion that is positioned along the longitudinal direction of the support pole and links the engagement portion and the operating portion .

In addition, in the stepladder/ladder combination of the present invention, it is preferable that the linking portion and the engagement portion are displaced upward by displacing the operating portion of the deregulation member upward when in the stepladder state.

In addition, in the stepladder/ladder combination of the present invention, it is preferable that the deregulation member is formed by bending a rod-shaped member, so that the engagement portion, the linking portion, and the operating portion are integrally formed.

Furthermore, in the stepladder/ladder combination of the present invention, the opening prevention mechanism includes two sets of arm members provided on both sides of the pair of ladder bodies, and in the deregulation member, the linking portion is provided on both ends of the operating portion, and the engagement portion is preferably provided on both ends of the deregulation member so as to be able to bend the two sets of arm members.

In addition, in the stepladder/ladder combination of the present invention, when in the ladder state, it is preferable that the deregulating member is positioned downward due to its own weight, so that the operating unit is positioned lower than the adjacent tread or the upper end surface of the top plate.

In addition, in the stepladder/ladder combination of the present invention, it is preferable that the operating unit has a displacement-permitting portion that can be displaced upward when in the stepladder state by being positioned lower than the lower end surface of the adjacent rung or the top plate, and a non-displaceable portion that cannot be displaced upward by being positioned higher than the lower end surface of the adjacent rung or the top plate.

In addition, in the stepladder combined with the ladder of the present invention, it is preferable that the deregulation member has the operating part provided along a plurality of the rungs or the top plate.

The ladder-cum-stepladder of the present invention has the advantage that it can be easily switched from the stepladder state to the closed state.

FIG. FIG. FIG. FIG. 2 is a cross-sectional view showing the ladder/stepladder in the stepladder state. A left side view showing the connection configuration of the ladder body. FIG. 4 is a bottom perspective view showing an assembly configuration of the opening prevention mechanism. 13 is a bottom perspective view showing an assembly procedure of the opening prevention mechanism. FIG. FIG. FIG. 13 is a cross-sectional view showing a state in which the restriction by the opening prevention mechanism is released. FIG. FIG. 13 is a cross-sectional view showing the opening prevention mechanism in the inverted ladder state.

Below, using Figures 1 to 11, we will explain stepladder 1, which is a ladder and stepladder according to one embodiment of the present invention. In this embodiment, the direction of the arrow shown in Figure 1 defines the direction of stepladder 1 in the stepladder state described below. That is, the axial direction (direction in which rungs 4 are installed) of rotation axis A (see dashed line in Figure 1) shown in Figure 1 is defined as the left-right direction of stepladder 1. In addition, the direction perpendicular to the left-right direction in the horizontal direction (the opening and closing direction of ladder bodies 2, 2) is defined as the front-rear direction of stepladder 1, and the direction perpendicular to the left-right direction and the front-rear direction is defined as the up-down direction of stepladder 1.

As shown in FIG. 1, the stepladder 1 according to this embodiment includes a pair of ladder bodies 2, 2 that have a common configuration. The ladder bodies 2, 2 are arranged in a generally V-shaped configuration in side view with their lower ends spaced apart from each other, and their upper ends are rotatably connected by hinges 6, 6.

As shown in Figure 5, the hinge 6 has a first hinge portion 6a and a second hinge portion 6b which are rotatably connected by a pivot support portion 6c. The first hinge portion 6a and the second hinge portion 6b are fixed to the upper ends of the posts 3, 3 which are on the same side in the left-right direction (facing each other and moving towards each other). This allows the hinge 6 to connect the opposing posts 3, 3 so that they can rotate relatively. In other words, the ladder bodies 2, 2 can rotate in directions in which they move towards and away from each other (in Figure 1, the front-to-rear direction of the stepladder 1).

Each ladder body 2 has a pair of long supports 3, 3. The supports 3, 3 are arranged so that the distance between them is greater at the bottom than at the top (approximately V-shaped when viewed from the front). The stepladder 1 in this embodiment has four supports 3. Each support 3 is bent at two points along the longitudinal direction to ensure strength, etc., so that the cross-sectional shape perpendicular to the longitudinal direction is approximately U-shaped. In addition, end fittings 3a are fixed to the lower end of each support 3.

A number of steps 4, 4... which are hollow tubular members, are placed at a specified distance between a pair of posts 3, 3 in the ladder body 2. The steps 4 are formed by cutting a linear extrusion with a specified cross-sectional shape to a specified length (see Figure 4). Each step 4 is fixed between the opposing inner surfaces of the posts 3 with rivets. In the stepladder 1 according to this embodiment, the posts 3, steps 4 and top plate 5 are light metal members made of aluminum or aluminum alloy. The steps 4 can also be fixed to the posts 3 using other fastening parts such as bolts and nuts.

Each ladder body 2 is provided with a top plate 5, 5 which is a hollow tubular member at its upper end. The top plate 5 is formed by cutting a linear extrusion molding with a specified cross-sectional shape to a specified length (see Figures 4 to 11). The top plate 5 is fixed between the opposing inner surfaces at the upper ends of the posts 3, 3 with rivets. In other words, the top plate 5 is provided in each ladder body 2 so as to connect the upper ends of the two posts 3, 3. It is also possible to fix the top plate 5 to the post 3 using other fastening parts such as bolts and nuts.

The stepladder 1 can take three main forms depending on the angle between the pair of ladder bodies 2, 2 (more specifically, the angle between the posts 3, 3, which move closer to and farther away from each other as the ladder bodies 2, 2 rotate relative to each other in a side view; the same applies below).

In the first form, as shown in Figure 1, the ladder bodies 2 and 2 form an angle of approximately 30 degrees, and the stepladder 1 is supported by four posts 3 (hereinafter, this form will be referred to as the "stepladder state"). In the stepladder state, the stepladder 1 is used in a state where it stands independently on the ground or floor.

The second state is shown in FIG. 2, in which the angle between the ladder bodies 2 and 2 is close to 0 degrees (hereinafter, this state will be referred to as the "closed state"). The closed state of the stepladder 1 is mainly used when storing or transporting.

In the third form, as shown in Figure 3, the ladder bodies 2 and 2 form an angle of approximately 180 degrees, and the stepladder 1 is supported by two posts 3 on one side (hereinafter, this form will be referred to as the "ladder state"). In the ladder state, the stepladder 1 is used with one (lower) ladder body 2 placed on the ground or floor, and the other (upper) ladder body 2 leaned against a wall or eaves.

The stepladder 1 is equipped with an opening prevention mechanism 7 that determines the angle between the ladder bodies 2 and 2 when in the stepladder or ladder state and restricts their relative displacement (rotation). A total of two opening prevention mechanisms 7 are provided on both the left and right sides of the upper ends of the ladder bodies 2 and 2. The opening prevention mechanisms 7 connect the posts 3 that are located on the same side in the left-right direction and are close to and spaced apart from each other in a pair of ladder bodies 2 and 2 that are connected to each other.

More specifically, the opening prevention mechanism 7 is rotatably supported on one of the posts 3, 3 (the left post 3 in FIG. 5) that face each other and are spaced apart on the ladder body 2, 2. The opening prevention mechanism 7 is then capable of engaging with the other of the posts 3, 3 (the right post 3 in FIG. 5) when the stepladder 1 is in both the stepladder state and the ladder state. Since each opening prevention mechanism 7 has the same configuration, the explanation in this embodiment will focus on the opening prevention mechanism 7 on the left side.

As shown in FIG. 5, the opening prevention mechanism 7 is an arm member formed by connecting a first arm body 7a and a second arm body 7b. In the opening prevention mechanism 7 provided on the left side of the stepladder 1, one end (the left end in FIG. 5) of the first arm body 7a is rotatably supported by a pivot 7c at the top of the rear support 3. One end of the second arm body 7b is rotatably connected to the other end of the first arm body 7a by a rotation connector 7d. In addition, in the opening prevention mechanism 7 provided on the right side of the stepladder 1, one end (the right end in FIG. 8) of the first arm body 7a is rotatably supported by a pivot 7c at the top of the front support 3.

An engagement end 7e is formed at the other end of the second arm body 7b. The engagement end 7e has an engagement member 7f biased by a torsion spring 7h and an engagement hole 7g that can be expanded or contracted by the displacement of the engagement member 7f. The engagement member 7f is biased by the torsion spring 7h in a direction that contracts (closes) the engagement hole 7g. When the stepladder 1 is in the stepladder state, as shown in Figures 1 and 6, the angle between the ladder bodies 2 and 2 is opened to about 30 degrees, and the engagement end 7e is engaged with the first lock pin P1 formed on the other support 3. At this time, the first lock pin P1 is inserted into the engagement hole 7g, and the engagement member 7f is biased by the torsion spring 7h, so that the engagement state between the engagement end 7e and the first lock pin P1 is maintained. Note that the configuration of the engagement end formed on the second arm body 7b is not limited to this embodiment, and it is also possible to engage the first lock pin P1 (as well as the second lock pin P2) with other configurations.

In this way, in the stepladder 1, the first arm body 7a is rotatably supported on one of the pillars 3, and the second arm body 7b is rotatably connected to the tip of the first arm body 7a and has a tip that can engage with the other pillar 3. In this embodiment, the pivot shaft 7c formed on one of the pillars 3 and the first lock pin P1 formed on the other pillar 3 are formed at the same vertical position.

The angular range of the second arm body 7b relative to the first arm body 7a is restricted by a stopper (not shown). Specifically, the second arm body 7b can rotate around the rotary connector 7d from a state close to the first arm body 7a to a state where the angle is approximately 185 degrees in the counterclockwise direction. In the stepladder 1 in the stepladder state, the rotary connector 7d is positioned downward due to the weight of the first arm body 7a and the second arm body 7b in their natural state, so the relative angle is approximately 185 degrees as shown in FIG. 5. As a result, the rotary connector 7d is positioned below the pivot shaft 7c and the first lock pin P1, and downward displacement from that position is restricted.

In this way, when the stepladder 1 is in the stepladder state, the support posts 3, 3 are connected by the opening stop mechanism 7, and the angle between the ladder bodies 2, 2 is fixed at approximately 30 degrees. At this time, even if a force is applied to the ladder bodies 2, 2 in a rotational direction that brings the ladder bodies 2, 2 closer together, the ladder bodies 2, 2 do not rotate relative to each other because the rotational connection part 7d is positioned below the rotation axis 7c and the first lock pin P1, and downward displacement of the rotational connection part 7d from this position is restricted.

Even if a force is applied to the ladder bodies 2,2 in a rotational direction that separates the ladder bodies 2,2, the ladder bodies 2,2 do not rotate relative to each other because the posts 3,3 are connected by the opening prevention mechanism 7. Therefore, the angle between the ladder bodies 2,2 remains at approximately 30 degrees, and the stepladder 1 maintains the stepladder state. When releasing the engagement between the engagement end 7e and the first lock pin P1, the user can displace the engagement member 7f against the biasing force of the torsion spring 7h, thereby disengaging the engagement end 7e from the first lock pin P1.

When the stepladder 1 is closed, as shown in FIG. 2, the engagement end 7e of the opening prevention mechanism 7 is engaged with the first lock pin P1, and the first arm body 7a or the second arm body 7b is rotated so that the angle formed on the lower side between the first arm body 7a and the second arm body 7b is 180 degrees or less. Specifically, a force is applied from below to the rotating connector 7d, and the first arm body 7a and the second arm body 7b are rotated relative to each other so that the rotating connector 7d is displaced upward. This releases the angle restriction of the ladder bodies 2 and 2, and the ladder bodies 2 and 2 can be rotated so that the angle formed by the ladder bodies 2 and 2 is smaller than about 30 degrees. Then, the stepladder 1 is closed by setting the angle formed by the ladder bodies 2 and 2 to about 0 degrees. In this way, when the stepladder is in the stepladder state, the rotating connector 7d is displaced upward and the arm member consisting of the first arm body 7a and the second arm body 7b is bent, and the stepladder 1 is in a closed state in which the ladder bodies 2 and 2 are close to each other.

When the stepladder 1 is in the ladder state, as shown in Figures 3 and 11, the engagement end 7e of the opening stop mechanism 7 is released from the first lock pin P1, and the angle between the ladder bodies 2 and 2 is opened to about 180 degrees, and the engagement end 7e is engaged with the second lock pin P2 formed on the upper end of the support 3. In this way, by connecting the support bodies 3 and 3 with the opening stop mechanism 7, the angle between the ladder bodies 2 and 2 is fixed at about 180 degrees. At this time, even if a force is applied to the ladder bodies 2 and 2 in a direction that changes the angle between the ladder bodies 2 and 2, the first arm body 7a and the second arm body 7b do not rotate relative to each other because the rotation axis 7c, the rotation connection part 7d, and the engagement end 7e are arranged in a straight line. Therefore, the angle between the ladder bodies 2 and 2 remains at about 180 degrees, and the stepladder 1 maintains the ladder state.

In the stepladder 1 according to this embodiment, the opening prevention mechanism 7 includes a deregulation unit 8 that releases the restriction on the relative displacement of the ladder bodies 2, 2 when the stepladder 1 is in the stepladder state. As shown in Figures 5 to 7, in this embodiment, the deregulation unit 8 is provided on the front surface of the upper part of the rear ladder body 2. The deregulation unit 8 includes guide members 81, 81 provided on the front end surfaces of the supports 3, 3 on both the left and right sides of the rear ladder body 2, and a rod-shaped deregulation member 82 that is supported at both left and right ends by the guide members 81, 81 and is bridged between the guide members 81, 81.

As shown in Figures 6 and 7, the guide member 81 is a long member that is provided along the longitudinal direction of the support 3. The guide member 81 is attached to the support 3 via a rivet (or a snap fit). A guide groove 81a is formed along the longitudinal direction on the inner surface of the guide member 81 in the left-right direction. In addition, a communication hole 81b that penetrates the guide member 81 in the left-right direction is opened at the lower end of the guide member 81.

The deregulation member 82 is a member in which the engagement parts 82a, the operation part 82b, and the linking parts 82c are integrally formed by bending a metal rod-shaped member. The deregulation member 82 is configured such that the engagement parts 82a formed at both ends are connected to the operation part 82b formed in the center via the linking parts 82c. In this embodiment, the deregulation member 82 is integrally configured, which makes it possible to provide the deregulation part 8 with a simple configuration.

As shown in Figures 5 and 8, when the stepladder 1 is in the stepladder state, each of the engagement portions 82a, 82a is positioned below the first arm body 7a or the second arm body 7b of each arm member provided on both the left and right sides of the ladder body 2. Specifically, as shown in Figure 5, the engagement portion 82a extending to the left side of the stepladder 1 is positioned below the first arm body 7a of the opening prevention mechanism 7 provided on the left side. On the other hand, as shown in Figures 6 to 10, the engagement portion 82a extending to the right side of the stepladder 1 is positioned below the second arm body 7b of the opening prevention mechanism 7 provided on the right side.

As shown in FIG. 8, when the stepladder 1 is in the stepladder state, the operating part 82b is arranged along the longitudinal direction of the top plate 5 on the underside close to the top plate 5. The linking parts 82c, 82c are arranged along the longitudinal direction of the support 3 and link the engaging parts 82a, 82a and the operating part 82b.

As shown in FIG. 6, the deregulation member 82 is supported by the guide member 81 by inserting the linking portion 82c into the guide groove 81a. At this time, the engagement portions 82a, 82a extend outward in the left-right direction through the communication hole 81b of the guide member 81, and their tips are positioned below the arm members (first arm body 7a and second arm body 7b).

In the stepladder 1 according to this embodiment, the stepladder 1 can be closed by operating the deregulation member 82 in the stepladder state. Specifically, as shown in FIG. 9, the user inserts his/her hand under the top board 5 to displace the operating portion 82b of the deregulation member 82 upward. This displaces the linking portions 82c and 82c and the engaging portions 82a and 82a upward. The engaging portions 82a and 82a then rotate the first arm body 7a and the second arm body 7b upward to bend the arm members.

That is, by displacing the engaging portion 82a upward, the first arm body 7a and the second arm body 7b are rotated relative to each other so that the rotating connection portion 7d is displaced upward. This releases the angle restriction of the ladder bodies 2, 2, and the ladder bodies 2, 2 can be rotated so that the angle they form is less than approximately 30 degrees. Then, as shown in FIG. 10, when the user supports the top board 5 from below, the ladder bodies 2, 2 move closer to each other due to their own weight, the relative angle between them becomes approximately 0 degrees, and the stepladder 1 is in a closed state.

In this way, when the stepladder 1 is in the stepladder state, the user can operate the operation unit 82b to place the stepladder 1 in the closed state. The user can also lift the top plate 5 immediately after operating the operation unit 82b upward. In other words, the user of the stepladder 1 can perform the operation of changing the stepladder state from the stepladder state to the closed state and the operation of lifting the stepladder 1 in the closed state almost simultaneously with a single touch.

As described above, in the stepladder 1 according to this embodiment, the de-restriction member 82 provided in the opening prevention mechanism 7 releases the restriction on the relative displacement of the ladder bodies 2, 2 when the stepladder 1 is in the stepladder state. This allows the user to transform the stepladder 1 from the stepladder state to the closed state simply by operating the de-restriction member 82 with one hand. In other words, even in a situation where it is difficult for the user to use both hands, such as when holding a tool, the stepladder 1 can easily transform from the stepladder state to the closed state.

In addition, according to the stepladder 1 of this embodiment, the opening prevention mechanism 7 that connects the pair of ladder bodies 2, 2 can be placed in a stepladder state or a ladder state by engaging/disengaging with the first lock pin P1 or the second lock pin P2 at the engagement end 7e. In other words, the restriction release member 82 of this embodiment can be used without any problems in the stepladder 1, which is also a ladder.

In addition, with the stepladder 1 according to this embodiment, when the stepladder 1 is in the stepladder state, the operating portion 82b of the deregulation member 82 is displaced upward, causing the engagement portion 82a to displace upward and the first arm body 7a and the second arm body 7b to rotate upward and bend the arm members. In this way, when the stepladder 1 is in the stepladder state, the user can operate the operating portion 82b to place the stepladder 1 in the closed state, and therefore the user can lift the top board 5 immediately after operating the operating portion 82b upward.

The engaging portion 82a of the deregulating member 82 can be configured to be located below either the first arm body 7a or the second arm body 7b. In other words, as long as the engaging portion 82a is configured to be displaced upward to bend the arm member, it does not matter whether the engaging portion 82a is located below either the first arm body 7a or the second arm body 7b.

In addition, in this embodiment, the deregulation member 82 is a rod-shaped member that integrally configures the engagement portions 82a, 82a, the operating portion 82b, and the linking portions 82c, 82c, but the configuration of the deregulation member is not limited to this embodiment.

For example, the deregulation member may be configured such that the operating portion, the linking portion, and the engaging portion are separate and connected to one another, and the user operates the operating portion to cause the engaging portion to push up the arm member and release the restriction imposed by the opening prevention mechanism 7. In this case, the user may pull the operating portion toward the user (pulling it forward or backward), causing the engaging portion to push up the arm member. However, from the viewpoint of being able to perform the operation of operating the operating portion and the operation of lifting the tabletop consecutively, it is preferable to configure the operating portion 82b to be operated upward, as in this embodiment.

The operating part and the linking part can also be constructed of a string, the engaging part can be rotatably attached to the support 3, and the engaging part can be connected to the ends of the linking part and the operating part. With this configuration, when the user pulls the operating part, the engaging part pushes up the arm member from below, bending it. In this way, as long as the engaging part is configured to release the restriction of the opening prevention mechanism 7 by operating the operating part, it can be used in the stepladder 1 even if it has a different configuration from the restriction release part 8.

In addition, according to the stepladder 1 of this embodiment, in the deregulation member 82, the linking portions 82c, 82c are provided at both ends of the operating portion 82b, and the engagement portions 82a, 82a are provided at both ends of the deregulation member 82 so that the two sets of arm members can be bent. This allows the user of the stepladder 1 to release the restrictions of the opening prevention mechanisms 7 on both the left and right sides by simply operating the operating portion 82b once. In other words, the user can change from the stepladder state to the closed state simply by operating the deregulation member 82 with one hand, making it easier to change the stepladder 1 from the stepladder state to the closed state.

The stepladder 1 may be configured so that a deregulation member is provided separately for each of the left and right opening prevention mechanisms 7. In this case, the stepladder 1 can be changed from the stepladder state to the closed state by operating each deregulation member.

In addition, according to the stepladder 1 of this embodiment, the deregulation unit 8 is provided only on one of the ladder bodies 2, but it is also possible to provide the deregulation unit 8 on both ladder bodies 2. In this case, the operating unit 82b can be operated near either the front or rear top plate 5.

In addition, according to the stepladder 1 of this embodiment, the user can directly operate the opening prevention mechanism 7 to change the stepladder 1 from the stepladder state to the closed state without operating the restriction release member 82. Specifically, the user applies force from below to the rotating connector 7d with his/her own hand, and rotates the first arm body 7a and the second arm body 7b relative to each other so that the rotating connector 7d is displaced upward. This releases the angle restriction of the ladder bodies 2 and 2, and the ladder bodies 2 and 2 can be rotated so that the angle between the ladder bodies 2 and 2 is smaller than about 30 degrees, and the stepladder 1 is in the closed state. In this way, the user of the stepladder 1 of this embodiment can transform the stepladder 1 from the stepladder state to the closed state regardless of whether the user operates the restriction release member 82 or the opening prevention mechanism 7.

In addition, according to the stepladder 1 of this embodiment, the operating part 82b of the deregulation unit 8 is configured to be located near the top board 5, but by changing the shape of the linking part 82c, etc., it is also possible to configure the operating part 82b to be located near the step 4. In this case, since the operating part 82b can be operated near the step 4, operability is not impaired even if the stepladder 1 is relatively long and the top board 5 is positioned high.

It is also possible to provide multiple operating parts and linking parts on the deregulation member 82 (for example, by branching off multiple connecting parts from the engagement part and providing an operating part on each), so that the operating parts are provided along the multiple rungs 4 or top plate 5. It is also possible to provide deregulation parts 8 on both ladder bodies 2 and 2, and provide operating parts along the multiple rungs 4 or top plate 5 on each ladder body 2 and 2. In this case, since the operating part 82b can be operated near the multiple rungs 4 or top plate 5 on both ladder bodies 2 and 2, high operability can be achieved regardless of the size or shape of the stepladder 1.

In addition, according to the stepladder 1 of this embodiment, the operating part 82b of the deregulation part 8 is formed at the same height along the top plate 5, but by forming the operating part by bending it, the relative position in the height direction with respect to the bottom end surface of the top plate 5 can also be changed depending on the longitudinal position. Specifically, the operating part is formed with a low-position displacement-permitting part and a high-position non-displaceable part. Then, when in the stepladder state, the displacement-permitting part is positioned below the bottom end surface of the adjacent top plate 5 (or tread 4), allowing the user to displace it upward by operating it from below. On the other hand, by positioning the non-displaceable part above the bottom end surface of the adjacent top plate 5 (or tread 4), it is impossible for the user to displace it upward by operating it from below.

As a result, when the user holds the portion of the top plate 5 that corresponds to the non-displaceable portion, the stepladder 1 can be lifted while still in the stepladder state. In other words, with this configuration, when moving the stepladder 1 in the stepladder state over a short distance, it is possible to support the top plate 5 and lift the stepladder 1 without having to transform the stepladder 1 into the closed state each time.

Furthermore, with the stepladder 1 according to this embodiment, when the ladder body 2 on which the deregulation section 8 is provided is placed on the upper side as shown in FIG. 11 in the ladder state, the deregulation member 82 is positioned downward due to its own weight. Therefore, the operating section 82b is positioned lower than the upper end surface of the adjacent top plate 5 (the back surface 5R shown in FIG. 11). This ensures that even when the user uses the stepladder 1 in the ladder state, the operating section 82b is positioned above the back surface 5R of the top plate 5 and does not obstruct use.

When the stepladder 1 is in a ladder state in which the ladder body 2 on which the deregulation unit 8 is provided is on the lower side, the operating unit 82b is located lower than the adjacent top plate 5 (see FIG. 8). In other words, even in this case, the operating unit 82b does not hinder the use of the top plate 5.

1. Stepladder (also used as a ladder)
2 Ladder body 3 Support
3a End fitting 4 Tread
5 Top plate 5R Back side
6 Hinge 6a First hinge portion
6b Second hinge portion 6c Rotation support portion
7 Opening prevention mechanism 7a First arm body
7b Second arm body 7c Rotation shaft
7d Rotational connection portion 7e Engagement end portion
7f Engagement member 7g Engagement hole
7h Torsion spring 8 Restriction release part
81 Guide member 81a Guide groove
81b Communication hole 82 Restriction release member
82a Engagement portion 82b Operation portion
82c Linkage A Rotation Axis
P1 First lock pin P2 Second lock pin

Claims (9)

A ladder/stepladder comprising a pair of ladder bodies each having two posts, a number of rungs stretched between the two posts, and a top plate connecting one ends of the two posts, the one ends of the ladder bodies being connected to each other so as to be capable of rotating relative to each other, and the ladder/stepladder combination can be transformed into a closed state in which the pair of ladder bodies are close to each other, a stepladder state in which the pair of ladder bodies are spaced apart by a predetermined distance, and a ladder state in which the pair of ladder bodies are opened 180 degrees,
A mechanism for preventing the pair of ladder bodies from moving relative to each other in either the stepladder state or the ladder state is provided.
The opening prevention mechanism includes a restriction release member that releases the restriction on the relative displacement of the pair of ladder bodies when in the step ladder state ,
The opening prevention mechanism includes at least one pair of arm members that are rotatably supported on one of the support pillars of the pair of ladder bodies that face each other and are spaced apart from each other, and that are engageable with the other of the support pillars in each of the stepladder state and the ladder state;
the arm member includes a first arm body rotatably supported on one side of the support pillar, and a second arm body rotatably connected to a tip end of the first arm body and having a tip end engageable with the other side of the support pillar,
In a step-ladder state, a rotation connection portion between the first arm body and the second arm body in the arm member is positioned lower than both ends of the arm body and is restricted from being displaced downward from the position,
When in the step ladder state, the rotating connector is displaced upward and the arm member is bent, so that the pair of ladder bodies are brought into a closed state in which they are close to each other,
A stepladder/ladder combination in which, by displacing the release member when in a stepladder state, either the first arm body or the second arm body is rotated upward to bend the arm member. The restriction release member is formed with an engagement portion that is disposed adjacent to the arm member when in the stepladder state, and an operation portion that is disposed adjacent to the tread or the top board when in the stepladder state,
The ladder/stepladder combination described in claim 1, wherein by displacing the operating portion of the deregulation member when in the stepladder state, the engagement portion is displaced, and the engagement portion rotates either the first arm body or the second arm body upward to bend the arm member. The engaging portion is disposed below the arm member when in a ladder state,
The operating unit is disposed along a longitudinal direction of the step bar or the tabletop on a lower side adjacent to the step bar or the tabletop when the stepladder is in a stepladder state,
The stepladder/ladder combination according to claim 2 , wherein the deregulation member is formed with a linking portion arranged along the longitudinal direction of the support and linking the engagement portion with the operating portion. The stepladder combined with ladder according to claim 3 , wherein the linking portion and the engaging portion are displaced upward by displacing the operating portion of the deregulating member upward in the stepladder state. The stepladder/ladder combination according to claim 4 , wherein the deregulation member is formed by bending a rod-shaped member, so that the engagement portion, the linking portion, and the operating portion are integrally formed. The opening prevention mechanism includes two sets of arm members provided on both sides of the pair of ladder bodies,
The stepladder/ladder combination according to claim 5 , wherein in the deregulation member, the linking portion is provided at both ends of the operating portion, and the engaging portion is provided at both ends of the deregulation member so as to bend the two sets of arm members. A ladder/stepladder combination as described in any one of claims 4 to 6 , wherein, in the ladder state, the deregulation member is positioned downward due to its own weight, so that the operating part is positioned lower than the upper end surface of the adjacent rung or top plate. A ladder/stepladder combination as described in any one of claims 4 to 7, wherein the operating unit is provided with a displacement-allowing portion which, when in the stepladder state, can be displaced upward by being positioned lower than the lower end surface of the adjacent rung or the top plate, and a non-displaceable portion which cannot be displaced upward by being positioned higher than the lower end surface of the adjacent rung or the top plate. The stepladder/ladder combination according to claim 4 , wherein the deregulating member is provided with the operating portion along a plurality of the rungs or the top plate.

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