stepladder

Abstract

To provide a stepladder that can be provided with a latch mechanism regardless of its size, and that can be easily changed from a stepladder state to a closed state.SOLUTION: A stepladder 1, which includes a pair of ladder bodies 2 and 2, each having two pillars 3 and 3, a plurality of treads 4 spanned between the pillars 3 and 3, and a top plate 5 connecting one ends of the pillars 3 and 3, in which the pair of ladder bodies are connected at the one ends thereof for relative rotation so as to be changeable between a closed state where the ladder bodies 2 and 2 are close together and a stepladder state where the ladder bodies 2 and 2 are separated in a spaced-apart manner, which includes a latch mechanism 7 that regulates the relative displacement between the ladder bodies 2 and 2 in the stepladder state and the latch mechanism 7 is provided with a release member 92 for releasing the regulation of the relative displacement of the ladder bodies 2 and 2 in the stepladder state, and in which the release member 92 is assembled to either one of the ladder bodies 2 via a pair of brackets 91 and 91 formed by a plurality of members and provided on both sides of the concerned ladder body 2 respectively.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a step ladder, and more particularly to a locking structure in a step ladder.

Background Art

[0002] Conventionally, a step ladder having a configuration in which ends of a pair of ladder bodies are rotatably connected is used (for example, see Patent Document 1). In such a step ladder, a configuration for restricting relative displacement of the ladder bodies in the step ladder state is used by a locking mechanism provided between columns constituting the pair of ladder bodies. In the case of the step ladder described in Patent Document 1, by operating the locking mechanism in the step ladder state, the restriction can be released and the step ladder can be set to a closed state in which it is folded.

[0003] On the other hand, a step ladder that can be set to a closed state in which it is folded by operating a locking mechanism provided between the ladder bodies constituting the step ladder is used (for example, see Patent Document 2). In such a step ladder, by the user lifting an operation portion in the locking mechanism between the ladder bodies, the pair of ladder bodies can be brought close to each other to set the step ladder to a closed state.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] According to the stepladder described in Patent Document 1, an opening stopper mechanism is connected to each of the two support columns that make up one of the ladder sections. Therefore, when the user of the stepladder changes from the stepladder state to the closed state, they had to operate both opening stopper mechanisms with both hands, or operate each opening stopper mechanism with one hand. As a result, in situations where it was difficult for the user to use both hands, such as when holding tools, it was not easy to change from the stepladder state to the closed state.

[0006] On the other hand, according to 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, this configuration, in which a pair of ladder bodies are connected by an opening / closing mechanism, has limitations on where it can be installed on a stepladder. That is, since the opening / closing mechanism is placed near the user's hand, it has sometimes been difficult to adopt it for relatively large stepladders.

[0007] This invention has been made in view of the above circumstances, and the problem that this invention aims to solve is to provide a step ladder that can be equipped with an opening stopper mechanism regardless of its size, and that can be easily changed from a step ladder state to a closed state. [Means for solving the problem]

[0008] The following describes the means to solve the above problems.

[0009] The stepladder according to the present invention comprises a pair of ladder bodies, each having two support columns, one or more rungs spanning between the two support columns, and a top plate connecting the upper ends of the two support columns, which are connected at their upper ends so as to be able to rotate relative to each other, and the stepladder is equipped with an opening mechanism that restricts the relative displacement of the pair of ladder bodies when they are in an open state separated by a predetermined distance. ,beforeThe opening restraint mechanism comprises two sets of arm members, each arm rotatably supported on opposite and spaced-together support columns on both sides of the pair of ladder bodies, with the ends of the arm members connected to each other so as to be rotatable relative to each other; and a release member that rotates one of the arm members upward to bend the two sets of arm members. The restriction release member comprises an engagement portion that engages with the arm member when in the open state, and an operating portion arranged along the longitudinal direction of the rung or the top plate. When in the open state, displacing the operating portion of the restriction release member displaces the engagement portion, causing the arm member to bend, thereby bringing the pair of ladder bodies into a closed state. The operating portion has a sliding contact surface that moves substantially parallel to the support column. It is. [Effects of the Invention]

[0010] The stepladder according to the present invention has the advantage that it can be equipped with an opening stopper mechanism regardless of its size, and can be easily switched from a stepladder state to a closed state. [Brief explanation of the drawing]

[0011] [Figure 1] A perspective view showing a step ladder in a step-ladder configuration. [Figure 2] A left side view showing the connection configuration of the ladder body. [Figure 3] A right-side cross-sectional view showing the connection configuration of the ladder body. [Figure 4] A cross-sectional view of the right side showing the state with the opening restraint mechanism released. [Figure 5] An exploded view showing the assembly structure of the de-regulation section. [Figure 6] A diagram showing the structure of the de-regulation section. [Figure 7] A cross-sectional view showing the internal structure of the bracket. [Figure 8] Cross-sectional view of line XX in Figure 6. [Figure 9] Right side view showing the bracket. [Figure 10] Exploded perspective view of the de-regulation component. [Figure 11] (a) through (c) are perspective views showing the brackets, respectively. [Modes for carrying out the invention]

[0012] Hereinafter, with reference to FIGS. 1 to 11, the step ladder 1 according to an embodiment of the present invention will be described. In the present embodiment, in the direction of the arrow shown in FIG. 1, the direction of the step ladder 1 in the open state (step ladder state) described later is defined. That is, the axial direction of the rotation axis A (refer to the dashed line in FIG. 1) shown in FIG. 1 (the laying direction of the tread 4) is taken as the left-right direction of the step ladder 1. Further, in the horizontal direction, the direction orthogonal to the left-right direction (the opening / closing direction of the ladder bodies 2·2) is taken as the front-back direction of the step ladder 1, and the direction orthogonal to the left-right direction and the front-back direction is defined as the up-down direction of the step ladder 1.

[0013] As shown in FIG. 1, the step ladder 1 according to the present embodiment includes a pair of ladder bodies 2·2 having a common configuration. The ladder bodies 2·2 are arranged such that the lower ends are separated from each other and spread out in a substantially V shape in a side view, and the upper ends of each are rotatably connected by hinges 6·6 which are rotation fittings.

[0014] As shown in FIG. 2, the hinge 6 has a first hinge portion 6a and a second hinge portion 6b which are rotatably connected by a rotation support portion 6c. And the first hinge portion 6a and the second hinge portion 6b are fixed to the upper ends of the columns 3·3 which are on the same side in the left-right direction (opposite and approaching / separating) via four rivets which are fixing members respectively. Thereby, the hinge 6 connects the opposing columns 3·3 so as to be relatively rotatable. That is, the ladder bodies 2·2 are made rotatable in the direction of approaching / separating from each other (in FIG. 1, the front-back direction of the step ladder 1). In the present embodiment, among the three rivets for fixing the hinge 6 to the front column 3, the two rivets R·R located on the rear side (refer to FIGS. 3 and 4) function as positioning members for a bracket 91 described later.

[0015] Each ladder body 2 includes a pair of columns 3·3 that are elongated bodies. The columns 3·3 are arranged such that the distance between them is larger at the lower side than at the upper side (in a substantially V-shaped configuration when viewed from the front). The step ladder 1 according to the present embodiment includes four columns 3. Each column 3 is bent at two locations along its longitudinal direction for the purpose of ensuring strength and the like. And the column 3 is formed with a back plate 3b and two side plates 3s·3s that are adjacent to the back plate 3b and face each other so that the shape of the cross section perpendicular to the longitudinal direction is substantially U-shaped (see FIG. 8). Also, an end fitting 3a is fixed to the lower end of each column 3.

[0016] Between the pair of columns 3·3 in the ladder body 2, a plurality of crosspieces 4·4···, which are hollow cylindrical members, are spanned at a predetermined interval. The crosspiece 4 is formed by cutting a linear extruded product having a predetermined cross-sectional shape to a predetermined length. Each crosspiece 4 is fixed between the opposing inner surfaces of the columns 3 by rivets. In the step ladder 1 according to the present embodiment, each column 3, crosspiece 4, and top plate 5 are members made of a light metal such as aluminum or an aluminum alloy. Note that it is also possible to fix the crosspiece 4 to the column 3 using other fastening parts such as bolts and nuts.

[0017] Each ladder body 2 is provided with top plates 5·5, which are hollow cylindrical members, at the upper end. The top plate 5 is formed by cutting a linear extruded product having a predetermined cross-sectional shape to a predetermined length. The top plate 5 is fixed between the opposing inner surfaces at the upper ends of the columns 3·3 by 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 columns 3·3. Note that it is also possible to fix the top plate 5 to the column 3 using other fastening parts such as bolts and nuts.

[0018] The step ladder 1 can be mainly set in the following open state or closed state according to the angle formed by the pair of ladder bodies 2·2 (specifically, the angle formed by the columns with 3·3 that approach and separate due to the relative rotation of the ladder bodies 2·2 in a side view, the same hereinafter).

[0019] In the open state, as shown in Figure 1, the ladder 1 is supported by four support columns 3 with the angle between the ladder sections 2 and 2 being approximately 30 degrees. In this specification, the open state will be referred to as the "ladder state" below. In the ladder state, the ladder 1 is used in a self-supporting state on the ground or floor. In the closed state, the angle between the ladder sections 2 and 2 is brought close to approximately 0 degrees. The closed state of the ladder 1 is mainly used when storing or transporting it.

[0020] In a third form, the stepladder 1 can be configured as a ladder with the angle between the ladder sections 2 and 2 being approximately 180 degrees, and supported by two support columns 3 on one side. That is, the stepladder 1 according to this embodiment is configured as a ladder-type stepladder. It should be noted that the present invention is not limited to ladder-type stepladders, but can be applied to stepladders of all configurations, including dedicated stepladders.

[0021] The stepladder 1 is equipped with an opening stopper mechanism 7 that defines the angle between the ladder bodies 2 and 2 and restricts their relative displacement (rotation) when in the stepladder state. There are a total of two sets of opening stopper mechanisms 7, one on each side of the upper end of the ladder bodies 2 and 2. The opening stopper mechanism 7 connects the support columns 3 that are positioned on the same side in the left-right direction and are close to and far apart from each other in a pair of ladder bodies 2 and 2 that are connected to each other.

[0022] More specifically, the locking mechanism 7 is rotatably supported on one of the opposing, spaced-out support columns 3-3 (the left support column 3 in Figure 2) in the ladder bodies 2-2. The locking mechanism 7 is then capable of engaging with the other support column 3-3 (the right support column 3 in Figure 2) when the stepladder 1 is in the stepladder state. Since both locking mechanisms 7 have the same configuration, this embodiment will focus on describing the left locking mechanism 7.

[0023] As shown in Figure 2, the opening stopper mechanism 7 is an arm member formed by connecting a first arm body 7a and a second arm body 7b. In the opening stopper mechanism 7 provided on the left side of the stepladder 1, the base end of the first arm body 7a (the left end in Figure 2) is pivotally supported on a pivot axis 7c at the top of the rear support column 3. The tip of the second arm body 7b is pivotally connected to the tip of the first arm body 7a by a rotating connecting part 7d. In the opening stopper mechanism 7 provided on the right side of the stepladder 1, the base end of the first arm body 7a is pivotally supported on a pivot axis 7c at the top of the front support column 3.

[0024] An engaging end 7e is formed at the base end of the second arm body 7b. The engaging end 7e comprises an engaging member 7f biased by a torsion spring 7h, and an engaging hole 7g that can be expanded or contracted by the displacement of the engaging member 7f. The engaging member 7f is biased by the torsion spring 7h in the direction of contracting (closing) the engaging hole 7g. When the stepladder 1 is in the stepladder state, as shown in Figure 1, with the angle between the ladder bodies 2 and 2 opened to approximately 30 degrees, the engaging end 7e is engaged with the first lock pin P1 formed on the other support column 3. At this time, the first lock pin P1 is inserted into the engaging hole 7g, and the engaging member 7f is biased by the torsion spring 7h, thereby maintaining the engaged state between the engaging end 7e and the first lock pin P1. Note that the configuration of the engaging end formed on the second arm body 7b is not limited to this embodiment, and it is also possible to engage with the first lock pin P1 (and the second lock pin P2) with other configurations.

[0025] Thus, in the stepladder 1, the base end of the first arm body 7a is rotatably supported on one of the support columns 3, and the tip of the second arm body 7b is rotatably connected to the tip of the first arm body 7a, with its base end being able to engage with the other support column 3. In other words, the opening stopper mechanism 7 has the base ends of the first arm body 7a and the second arm body 7b rotatably supported on the opposing support columns 3, 3 which are closer together and further apart, and the tips of the first arm body 7a and the second arm body 7b are connected to each other so as to be rotatable relative to each other. In this embodiment, the pivot shaft 7c formed on one of the support columns 3 and the first lock pin P1 formed on the other support column 3 are formed at the same vertical position.

[0026] The angle 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 is rotatable around the rotating joint 7d from a state close to the first arm body 7a to a state where the angle in the counterclockwise direction is open to approximately 185 degrees. In the stepladder 1 in its stepladder state, the first arm body 7a and the second arm body 7b, in their natural state, have their rotating joint 7d positioned below due to their own weight, resulting in a relative angle of approximately 185 degrees as shown in Figure 2. As a result, the rotating joint 7d is positioned below both ends of the first arm body 7a and the second arm body 7b (the pivot axis 7c and the first lock pin P1), and displacement below this position is restricted.

[0027] Thus, when stepladder 1 is in the stepladder state, the angle between the ladder bodies 2 and 2 is fixed at approximately 30 degrees by connecting the support columns 3 and 3 with the opening / closing mechanism 7. In this case, even if a force is applied to the ladder bodies 2 and 2 in a rotational direction that brings them closer together, the rotating connecting part 7d is located below both ends of the first arm body 7a and the second arm body 7b, and the displacement of the rotating connecting part 7d below that position is restricted, so the ladder bodies 2 and 2 do not rotate relative to each other.

[0028] Furthermore, even if a force is applied to the ladder bodies 2 and 2 in a rotational direction that separates them, the ladder bodies 2 and 2 do not rotate relative to each other because the support columns 3 and 3 are connected by the opening stopper mechanism 7. As a result, the angle between the ladder bodies 2 and 2 remains at approximately 30 degrees, and the stepladder 1 maintains its stepladder state. In addition, to release the engagement between the engaging end 7e and the first lock pin P1, the user can displace the engaging member 7f against the biasing force of the torsion spring 7h, thereby detaching the engaging end 7e from the first lock pin P1.

[0029] To close the stepladder 1, with the engaging end 7e of the opening stopper mechanism 7 engaged with the first lock pin P1, the first arm body 7a or the second arm body 7b is rotated so that the angle formed below 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 connecting part 7d, causing the first arm body 7a and the second arm body 7b to rotate relative to each other so that the rotating connecting part 7d is displaced upward. This releases the angle restriction of the ladder bodies 2 and 2, allowing the ladder bodies 2 and 2 to rotate so that the angle formed by them is less than approximately 30 degrees. By setting the angle formed by the ladder bodies 2 and 2 to approximately 0 degrees, the stepladder 1 is closed. In this way, by displacing the rotating connecting part 7d upward when the stepladder is in the stepladder state and bending the arm members consisting of the first arm body 7a and the second arm body 7b, the stepladder 1 is closed with the ladder bodies 2 and 2 close together.

[0030] To convert stepladder 1 into a ladder, the engagement of the engaging end 7e in the opening stopper mechanism 7 with the first lock pin P1 is released, and with the ladder bodies 2 and 2 open to an angle of approximately 180 degrees, the engaging end 7e is engaged with the second lock pin P2 formed on the upper end of the support column 3. In this way, by connecting the support columns 3 and 3 with the opening stopper mechanism 7, the angle of the ladder bodies 2 and 2 is fixed at approximately 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 of 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 pivot axis 7c, the rotating connecting part 7d, and the engaging end 7e are arranged in a straight line. Therefore, the angle of the ladder bodies 2 and 2 remains at approximately 180 degrees, and stepladder 1 maintains its ladder state.

[0031] As described above, the stepladder 1 according to this embodiment is configured as a stepladder that also functions as a ladder, so an engaging end 7e is provided at the base end of the second arm body 7b in the opening stopper mechanism 7, and the second arm body 7b is detachably attached to the first lock pin P1 and the second lock pin P2 of the support column 3. However, if the stepladder 1 is configured as a dedicated stepladder, it is also possible to configure the base end of the second arm body 7b to be rotatably and non-detachably connected to the position of the first lock pin P1 on the support column 3.

[0032] In the stepladder 1 according to this embodiment, the opening stopper mechanism 7 includes a restriction release part 9 that releases the restriction on relative displacement between the ladder bodies 2 and 2 when the stepladder 1 is in the stepladder state. As shown in Figures 2 to 4, in this embodiment, the restriction release part 9 is provided on the rear surface of the upper part of the front ladder body 2.

[0033] As shown in Figure 5, the restriction release section 9 comprises brackets 91-91 provided on the rear side plates 3s of the left and right support columns 3-3 on the front ladder body 2 (specifically, a left bracket 91L provided on the left support column 3, and a right bracket 91R provided on the right support column 3 (see Figures 5 and 6)), and a rod-shaped restriction release member 92 that is supported at both ends by the left and right brackets 91-91 and spans between the brackets 91-91. In this embodiment, the left bracket 91L and the right bracket 91R have the same configuration except that they are formed in a symmetrical shape, so the left bracket 91L will be described below, and a detailed description of the right bracket 91R will be omitted.

[0034] In this embodiment, the restriction release member 92 is formed by combining multiple (three in this embodiment) members. Specifically, as shown in Figure 10, the restriction release member 92 is constructed by assembling two crank-shaped metal rod-shaped members to a resin columnar member. The columnar member can also be made of a metal such as aluminum alloy.

[0035] The metal rod-shaped member has an outer end formed as an engaging portion 92a and an inner end formed as an insertion portion 92d. A connecting portion 92c is formed between the engaging portion 92a and the insertion portion 92d, substantially perpendicular to both the engaging portion 92a and the insertion portion 92d. The columnar member is a columnar member formed in an isosceles trapezoidal shape in a cross-sectional view perpendicular to the longitudinal direction, and is formed as an operating portion 92b.

[0036] Holes 92e are formed at both ends of the operating portion 92b. As shown in Figure 10, by inserting the insertion portion 92d into each of the holes 92e, a restriction release member 92 is formed, which is a combination of a rod-shaped member and a columnar member. Thus, the restriction release member 92 is formed by combining a pair of rod-shaped members, each having an engaging portion 92a and a linking portion 92c integrally formed at both ends, with an operating portion 92b provided in the center.

[0037] In the release member 92, the hole 92e formed in the operating portion 92b has a slightly larger diameter than the insertion portion 92d. Therefore, when forming the release member 92, the insertion portion 92d is loosely fitted into the hole 92e (see Figures 7 and 9). As a result, the operating portion 92b and the rod-shaped members constituting the engaging portion 92a and the linking portion 92c are able to rotate relative to each other around the axis in the longitudinal direction of the operating portion 92b, and are also able to displace relative to each other in the axial direction.

[0038] As shown in Figure 9, in the restriction release member 92, a sliding contact surface 92f is formed on the front surface of the operating part 92b (the surface corresponding to the base of the isosceles trapezoid). In addition, in the restriction release member 92, an operating surface 92g is formed on the lower surface of the operating part 92b (the surface corresponding to the lower side of the isosceles trapezoid).

[0039] As shown in Figures 2 and 3, the respective engaging portions 92a and 92a of the release member 92 are positioned below the first arm body 7a or the second arm body 7b of the arm members provided on both the left and right sides of the ladder body 2 when the stepladder 1 is in the stepladder state. Specifically, as shown in Figure 6, the engaging portion 92a extending to the left side of the stepladder 1 is positioned below the first arm body 7a of the opening stopper mechanism 7 provided on the left side. On the other hand, as shown in Figure 6, the engaging portion 92a extending to the right side of the stepladder 1 is positioned below the second arm body 7b of the opening stopper mechanism 7 provided on the right side.

[0040] As shown in Figures 3 and 6, the operating section 92b is positioned along the longitudinal direction of the top plate 5 on the underside, close to the top plate 5, when the stepladder 1 is in the stepladder state. The connecting sections 92c, 92c are positioned along the longitudinal direction of the support column 3 and connect the engaging sections 92a, 92a and the operating section 92b.

[0041] The restriction release member 92 is attached to the ladder body 2 via a pair of brackets 91, 91 provided on both sides of the front ladder body 2. As shown in Figures 5 and 6, the brackets 91 are elongated members provided along the side plates 3s of the support column 3.

[0042] As shown in Figures 11(a) to (c), the bracket 91 comprises a bracket body portion 91a that houses the connecting portion 92c of the restriction release member 92, and a clip portion 91b. An opening 91c that opens horizontally is formed in the lower rear surface of the bracket body portion 91a. The opening 91c is an insertion port for inserting the restriction release member 92 into the bracket 91 when it is assembled to the ladder body 2 (see Figure 5).

[0043] As shown in Figure 11, a sliding contact portion 91h is formed on the upper side of the front inner circumferential surface of the bracket body portion 91a. A restricting wall 91f is formed on the side surface of the bracket body portion 91a as a restricting portion that restricts the displacement of the engaging portion 92a of the release member 92 in a direction toward each other. A bottom portion 91i is formed at the lower end of the bracket body portion 91a to support the engaging portion 92a of the release member 92. A guide projection 91g is formed near the upper side of the opening 91c on the rear inner circumferential surface of the bracket body portion 91a, projecting toward the inside of the bracket body portion 91a.

[0044] A slit 91j is formed between the bracket body 91a and the clip portion 91b. As shown in Figure 8, the bracket 91 is fixed to the support column 3 by inserting the rear side plate 3s of the support column 3 into the slit 91j and clamping the side plate 3s between the bracket body 91a and the clip portion 91b.

[0045] Specifically, the bracket body portions 91a of the pair of brackets 91-91 are formed in a cylindrical shape with opposing sides (the inner sides in the ladder body 2) open. Multiple insertion protrusions 91k are formed protruding from the side of the bracket body portion 91a facing the slit 91j. When the side plate 3s of the support column 3 is inserted into the slit 91j, the insertion protrusions 91k are inserted into recesses formed in the side plate 3s, and the side plate 3s is clamped between the bracket body portion 91a and the clip portion 91b.

[0046] At the tip of the clip portion 91b, a flange portion 91d is formed along the longitudinal direction of the bracket 91, bent at approximately a right angle. In the middle of the flange portion 91d in the longitudinal direction, two positioning portions 91e·91e are formed in a notched shape. When the bracket 91 is assembled to the support column 3, rivets R for fixing the hinge 6 are inserted into each of the positioning portions 91e (see Figures 3 and 4). This positions the bracket 91 relative to the ladder body 2.

[0047] Thus, in this embodiment, the bracket 91 is configured to be easily positioned without requiring a separate positioning member. It is also possible to position the bracket 91 relative to the support column 3 using a fixing device that secures a member different from the hinge 6 to the support column 3 (for example, a rivet that secures the rung 4 to the support column 3, or a shaft member that rotatably supports the opening stopper mechanism 7 to the support column 3).

[0048] When assembling the bracket 91 and the restriction release member 92 that constitute the restriction release section 9 to the ladder body 2, first, as shown in Figure 5, the two brackets 91·91 (left bracket 91L and right bracket 91R) are fixed from the inside to the side plates 3s of the left and right support columns 3, respectively. Then, the restriction release member 92 is inserted through the openings 91c·91c of the brackets 91·91. At this time, the upper side of the opening 91c on the rear surface of the bracket body 91a is elastically deformed by the restriction release member 92.

[0049] When the engaging portion 92a of the release member 92 passes through the opening 91c, the engaging portion 92a and the connecting portion 92c of the release member 92 are housed inside the bracket 91, as shown in Figure 6. Inside the bracket 91, the release member 92 is supported by the bottom portion 91i of the bracket 91.

[0050] As described above, when the de-restriction member 92 is assembled to the brackets 91, 91, the sliding contact surface 92f of the operating part 92b and the sliding contact part 91h, which is the inner circumferential surface of the bracket body 91a, come into sliding contact, as shown in Figure 9. This restricts the rotation of the operating part 92b relative to the bracket 91. The operating part 92b is positioned such that when the stepladder 1 is in the open position, the operating surface 92g faces downwards and is horizontal.

[0051] In the stepladder 1 according to this embodiment, the stepladder 1 can be closed by operating the release member 92 while it is in the stepladder state. Specifically, as shown in Figure 4, the user inserts their hand under the top plate 5 and pushes up the operating surface 92g of the release member 92, displacing the operating part 92b upward. This causes the connecting parts 92c·92c and the engaging parts 92a·92a to be displaced upward. The engaging parts 92a·92a then rotate the first arm body 7a and the second arm body 7b upward, bending the arm members.

[0052] Specifically, by displacing the engaging portion 92a upward, the first arm body 7a and the second arm body 7b are rotated relative to each other so that the rotating connecting portion 7d is displaced upward. This releases the angle restriction of the ladder bodies 2 and 2, allowing them to rotate so that the angle between them is less than approximately 30 degrees. Then, when the user supports the top plate 5 from below, the ladder bodies 2 and 2 move closer to each other due to their own weight, and their relative angle becomes approximately 0 degrees, bringing the stepladder 1 into a closed state.

[0053] In this embodiment, when the vertical position of at least a portion of the operating surface 92g of the operating section 92b approaches the lower surface of the top plate 5 located directly above the release member 92, the engaging portions 92a and 92a are configured to bend the arm member consisting of the first arm body 7a and the second arm body 7b. This makes it possible to change the stepladder 1 from an open state to a closed state even when the user pushes upward either the left or right end of the operating surface 92g.

[0054] In this way, when the stepladder 1 is in the stepladder state, the user can close the stepladder 1 by operating the control unit 92b. Furthermore, the user can lift the top plate 5 in conjunction with the upward operation of the control unit 92b. In other words, the user of the stepladder 1 can perform the action of closing the stepladder 1 from the stepladder state and lifting the closed stepladder 1 almost simultaneously with a single touch.

[0055] In this embodiment, the rigidity of the operating section 92b in the longitudinal direction is increased by forming the operating section 92b from a columnar member made of resin. Therefore, even if the user lifts the top plate 5 while operating the operating section 92b, bending or deformation of the operating section 92b can be suppressed.

[0056] Furthermore, when the stepladder 1 is in the stepladder state, the operating part of the restriction release member can be operated to rotate and displace the linkage part, thereby causing the first arm body 7a and the second arm body 7b to rotate relative to each other. This configuration also releases the angle restriction of the ladder bodies 2 and 2, allowing the stepladder 1 to be placed in the closed state.

[0057] In this embodiment of the stepladder 1, when the ladder body 2, which is equipped with the restriction release part 9, is in the upper position, the restriction release member 92 is positioned downward due to its own weight. Therefore, the operating part 92b is positioned below the upper end surface of the adjacent top plate 5 (as shown in Figure 4, but upside down). This ensures that even when the user uses the stepladder 1 in the ladder position, the operating part 92b does not obstruct use by being above the underside 5R of the top plate 5.

[0058] On the other hand, when the stepladder 1 is in a ladder configuration with the ladder body 2, which is equipped with the restriction release section 9, on the lower side, the operating section 92b is located below the adjacent top plate 5, as shown in Figure 3. In other words, even in this case, the operating section 92b does not obstruct the use of the top plate 5.

[0059] As described above, in the stepladder 1 according to this embodiment, the restriction release member 92 provided in the opening stopper mechanism 7 releases the restriction on relative displacement in the ladder bodies 2 and 2 when the stepladder 1 is in the stepladder state. This makes it possible for the user to transform the stepladder 1 from the stepladder state to the closed state simply by operating the restriction release member 92 with one hand. In other words, even in situations where it is difficult to use both hands, such as when the user is holding tools, the stepladder 1 can be easily transformed from the stepladder state to the closed state.

[0060] Furthermore, in the stepladder 1 according to this embodiment, the operating part 92b of the restriction release part 9 is positioned near the top plate 5. However, by changing the shape of the bracket 91 and the connecting part 92c, it is also possible to position the operating part 92b near the rung 4. In this case, the operating part 92b can be operated near the rung 4, so operability is not impaired even when the stepladder 1 is relatively long and the position of the top plate 5 is high.

[0061] As described above, when the operating section 92b is positioned near the rung 4, the engaging sections 92a and 92a are configured to bend the arm member consisting of the first arm body 7a and the second arm body 7b when the vertical position of at least a portion of the operating surface 92g of the operating section 92b is close to the lower surface of the rung 4 located directly above the release member 92. This makes it possible to change the stepladder 1 from an open state to a closed state even when the user pushes either the left or right end of the operating surface 92g upward.

[0062] Thus, in the stepladder 1 according to this embodiment, the degree of freedom in the placement of the operating section 92b can be increased by changing the shape of the restriction release member 92. That is, even in the case of a relatively large stepladder 1, when the opening stopper mechanism 7 is at a height that is difficult for the user to reach, the operating section 92b can be placed near the user's hands. In other words, according to the stepladder 1 according to this embodiment, it is possible to provide the opening stopper mechanism 7 and the restriction release section 9 regardless of the size of the stepladder 1.

[0063] Furthermore, the engaging portion 92a of the restriction release member 92 can also be configured to be positioned below either the first arm body 7a or the second arm body 7b. In other words, as long as the engaging portion 92a is displaced upward and bends the arm member, it is acceptable to position the engaging portion 92a below either the first arm body 7a or the second arm body 7b.

[0064] Furthermore, according to the stepladder 1 of this embodiment, in the restriction release member 92, the connecting parts 92c-92c are provided at both ends of the operating part 92b, and the engaging parts 92a-92a are provided at both ends of the restriction release member 92 so as to bend two sets of arm members. As a result, the user of the stepladder 1 can release the restriction of the opening stopper mechanism 7 on both the left and right sides by operating the operating part 92b once. In other words, the user can change from the stepladder state to the closed state by simply operating the restriction release member 92 with one hand, making it easier to change the stepladder 1 from the stepladder state to the closed state.

[0065] Furthermore, in this embodiment of the stepladder 1, the restriction release section 9 is provided only on one of the ladder bodies 2, but it is also possible to provide the restriction release section 9 on both of the ladder bodies 2. In this case, the operation section 92b can be operated near either the front or rear top plate 5.

[0066] Furthermore, according to the stepladder 1 of this embodiment, it is also possible for the user to directly operate the opening stopper mechanism 7 without operating the restriction release member 92, thereby changing the stepladder 1 from the stepladder state to the closed state. Specifically, the user applies force from below to the rotating joint 7d with their own hand, causing the first arm body 7a and the second arm body 7b to rotate relative to each other so that the rotating joint 7d is displaced upward. This releases the angle restriction of the ladder bodies 2 and 2, allowing the ladder bodies 2 and 2 to rotate so that the angle formed by them becomes less than approximately 30 degrees, and the stepladder 1 becomes the closed state. In this way, the user of the stepladder 1 of this embodiment can change the stepladder 1 from the stepladder state to the closed state regardless of whether they operate the restriction release member 92 or the opening stopper mechanism 7.

[0067] As described above, in the stepladder 1 according to this embodiment, the restriction release member 92 is formed by combining two rod-shaped members that are bent into a crank shape to constitute the engaging portion 92a and the linking portion 92c, and a columnar member that constitutes the operating portion 92b. This makes it easy to adjust the shape, such as the alignment of the rod-shaped member and the columnar member, when forming the restriction release member 92. For this reason, the dimensional accuracy of each part can be set lower compared to when the restriction release member is formed from a single piece (for example, when it is formed by bending a single rod-shaped member). In other words, it is possible to form the restriction release member 92 with accuracy using a simple structure.

[0068] Furthermore, in this embodiment, the release member 92 is formed by loosely fitting one end (insertion portion 92d) of the rod-shaped member constituting the engaging portion 92a and the linking portion 92c into the holes 92e formed at both ends of the operating portion 92b. As a result, even if an external force is applied to the release member 92 and the engaging portion 92a or the linking portion 92c deforms relative to the operating portion 92b, the relative displacement between the rod-shaped member and the columnar member is permitted, allowing the release member 92 to return to its original shape. In other words, the degree of freedom of the shape of the release member 92 can be increased, preventing the release member 92 from remaining in a deformed state and becoming stuck inside the bracket 91, making it difficult to move up and down.

[0069] Furthermore, in this embodiment, the release member 92 is configured such that the rod-shaped members constituting the engaging portion 92a and the linking portion 92c and the operating portion 92b are rotatable relative to each other around the axis in the longitudinal direction (left-right direction) of the operating portion 92b, and are also rotatable relative to each other in the axial direction. This increases the degree of freedom of the shape of the release member 92, allowing the release member 92 to be displaced more smoothly inside the bracket 91.

[0070] Furthermore, in the release member 92 of this embodiment, a sliding contact surface 92f is formed on the operating portion 92b. When the release member 92 is assembled to the bracket 91, the sliding contact surface 92f and the contacted portion 91h, which is the inner circumferential surface of the bracket body 91a, come into sliding contact, thereby restricting the rotation of the operating portion 92b relative to the bracket 91. This makes it possible to keep the orientation of the operating portion 92b relative to the bracket 91 constant at all times, and to stably position the operating portion 92b.

[0071] Furthermore, in the release member 92 of this embodiment, an operating surface 92g is formed on the operating section 92b, and the operating section 92b is positioned such that the operating surface 92g is horizontal and facing downwards when in the open state, as shown in Figure 9. As a result, the operating surface 92g is always in contact with the user's hand when operating the operating section 92b, thereby improving the user's operating feel.

[0072] Furthermore, in the stepladder 1 according to this embodiment, the bracket body portion 91a of the bracket 91 has an opening 91c into which the restriction release member 92 can be inserted when the bracket 91 is assembled to the ladder body 2. Thus, in this embodiment, it is not necessary to assemble the bracket 91 and the restriction release member 92 to the ladder body 2 at the same time, and the bracket 91 and the restriction release member 92 can be assembled to the ladder body 2 in stages. In other words, the restriction release part 9 can be easily assembled to the ladder body 2, making it easy to assemble the stepladder 1.

[0073] Furthermore, in the stepladder 1 according to this embodiment, the opening 91c formed in the bracket body 91a is formed on the opposite side (the rear surface in this embodiment) of the clip portion 91b of the bracket body 91a. This makes it possible to insert the restriction release member 92 through the opening 91c while the bracket 91 is assembled to the ladder body 2 via the clip portion 91b.

[0074] Furthermore, in the stepladder 1 according to this embodiment, a bottom portion 91i is formed at the lower end of the bracket body portion 91a to support the engaging portion 92a of the restriction release member 92. By supporting the engaging portion 92a with this bottom portion 91i, the bracket 91 is able to stably hold the restriction release member 92.

[0075] Furthermore, in the stepladder 1 according to this embodiment, a restricting wall 91f is formed on the bracket body 91a as a restricting part that restricts the inward displacement of the engaging part 92a so that they come closer together when the release member 92 is located lower inside the bracket 91. This prevents the engagement between the engaging part 92a and the first arm body 7a and the second arm body 7b from becoming insufficient due to the inward displacement of the engaging part 92a, which would prevent the arm members from bending.

[0076] In this embodiment, the restricting wall 91f of the bracket body 91a is formed on the lower side of the opening 91c. This allows for elastic deformation of the upper side of the opening 91c in the bracket body 91a when the release member 92 is inserted into the opening 91c.

[0077] Furthermore, it is also possible to form a restricting projection on the inner surface of the bracket body portion 91a as a restricting portion that restricts the inward displacement of the engaging portion 92a of the release restricting member 92 so that they come into close proximity to each other.

[0078] Furthermore, in the stepladder 1 according to this embodiment, as shown in Figures 8, 9, and 11, a guide projection 91g is formed on the upper side of the opening 91c on the inner surface of the bracket body 91a, which restricts deformation in the direction that the engaging portions 92a, 92a of the release member 92 move closer to each other. As a result, when the release member 92 is inserted into the opening 91c, the guide projection 91g engages with the connecting portion 92c of the release member 92. Therefore, it is possible to prevent the release member 92 from deforming so that the engaging portions 92a move closer to each other due to the elastic force of the bracket body 91a, and to smoothly house the release member 92 inside the bracket 91. [Explanation of Symbols]

[0079] 1. Step ladder 2. Ladder 3 Post 3a End fitting 3b Back plate 3s Side plate 4 steps 5 top plate 6. Hinge (rotating fitting) 6a. First hinge section 6b Second hinge section 6c Rotating support section 7. Opening stopper mechanism 7a. First arm body 7b Second arm body 7c Rotation axis 7d Rotating connection part 7e Engagement end part 7f Engaging member 7g Engaging hole 7h torsion spring 9. Deregulation Section 91 Bracket 91L Left Bracket 91R Right bracket 91a Bracket body 91b Clip part 91c Opening 91d Flange portion 91e Positioning portion 91f Regulating wall (regulating section) 91g Guide projection 91h Sliding contact part 91i Bottom part 91j Slit 91k Insertion projection 92 Restriction release member 92a Engagement part 92b Control Unit 92c Linkage Unit 92d Insertion part 92e Hole part 92f Sliding surface 92g Operation surface A Rotary shaft P1 First locking pin P2 Second lock pin R rivet

Claims

1. A stepladder comprising a pair of ladder bodies each having two support posts, one or more rungs spanning between the two support posts, and a top plate connecting the upper ends of the two support posts, the pair of ladder bodies being connected at their upper ends so as to be rotatable relative to each other, and equipped with an opening mechanism that restricts the relative displacement of the pair of ladder bodies when they are in an open state separated by a predetermined distance, The opening stopper mechanism comprises two sets of arm members, each arm rotatably supported on opposite and spaced-together support columns on both sides of the pair of ladder bodies, with the ends of the arm members connected to each other so as to be rotatable relative to each other; and a release member that rotates one of the arm members upward to bend the two sets of arm members. The restriction release member comprises an engaging portion that engages with the arm member when in the open state, and an operating portion arranged along the longitudinal direction of the rung or the top plate. When in the open state, displacing the operating portion of the restriction release member causes the engaging portion to be displaced, the arm member to bend, and the pair of ladder bodies are brought into a closed state in close proximity. A stepladder having a sliding contact surface formed on the operating section that moves substantially parallel to the support column.

2. The stepladder according to claim 1, wherein the operating part has an operating surface, and the operating part is provided such that when it is in the open state the operating surface is horizontal and facing downwards.

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