JPS6217289A - Foldable ladder - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a folding ladder whose four legs can be folded back and forth and left and right.

(Prior art) Folding ladders are known to have a structure that allows them to be folded into two pieces using the bent part at the top as a fulcrum. Conventionally, there was no one equipped with a treadle with such a high degree of strength.

(Problem to be Solved by the Invention) The bifold type ladder as described above has a sense of stability because the legs can be extended in the front and rear directions when in use, but the legs can be opened in an inverted V shape on the sides, so the upper part cannot be extended. It is difficult to provide a tread of sufficient width, and if a tread is provided, it becomes impossible to fold the ladder in the width direction (left and right) due to the tread. Problems arose, such as being inconvenient to carry and taking up a large amount of space when stored.

(Means for Solving the Problems) This invention was made in view of the above-mentioned prior art, that is, four leg rods 1 are provided oppositely on the front, rear, left and right sides, and the leg rods 1 are installed oppositely on the front and back.・The upper end of 1 is fixed to a connecting fitting 3 that opens and closes mutually using the pivot 2 as a fulcrum, and a bendable tension rod 4 is arranged between the front and rear leg rods, so that the base can be connected to the left and right leg rods 1 and 1. Left and right horizontal rods 5 and 5 pivoted at the top, middle, and bottom
The inner end of the middle movable rod 6 is arranged parallel to the left and right leg rods.
The lower end of the movable rod 6 is inserted into the guide frame 8 at the upper end of the left and right support rods 7, which are pivotally connected to the lower ends of the left and right leg rods 1. One end of an arm 9 forming a joining part 10 in which the upper end of the other movable rod 6 intervenes is pivotally attached to the upper end of one movable rod 6 that slightly protrudes from the upper end of the arm 9, and the left and right side plates 11-11 are attached to the other end of the arm. The bottom of the middle plate 12 of the freely bendable tread A is eccentrically pivoted, and a stopper 13 that locks the lower end of the other leg rod 1, 1 when folded is fixed to one of the support rods 7 and 7. By attaching the grip bands 14 to appropriate positions on the rods 1, 1, a folding ladder is provided which does not have the above-mentioned disadvantages.

(Operation) When folding the book ladder that is currently in the open position, first pull the tension rod 4.
Bend and bring the front and rear leg rods 1.1 close together.

The upper ends of the leg rods are fixed to the connecting metal fittings 3, and since the connecting metal fittings mutually open and close using the pivot 2 as a fulcrum, the legs are opened in an inverted V shape, and the distance between the front and rear leg rods narrows, and the legs can be folded in the front and back direction. At the same time, the tread A, which is located at the upper horizontal lever 5...K, has the middle plate 12 pivoted eccentrically to the arm 9, so it can be moved horizontally and vertically using the pivot point as a fulcrum. The upper end of the movable lever 6 on the footboard side intervenes in the joint portion 10 of the arm (see FIG. 2).

Next, when you grasp the movable rod 6 or a part of the left and right horizontal rods 5 and lift it up, the horizontal rods 5 will have their inner ends pointing upwards with the base as a fulcrum, and at the same time, the left and right support rods 7 will also point upwards, so the left and right When the leg rods 5 are pressed inward, they will come close together (see Fig. 3), and the horizontal rods 5 will finally become vertical, and the left and right leg rods will be folded in parallel. Therefore, by locking the lower ends of the other leg rods 1 and 1 to the stopper 13 fixed to one of the support rods 7 and 7, the front and rear leg rods will no longer open unexpectedly (see Figure 5), and the Since the left and right side plates 11, 11 of the tread A located at the upper end of the leg are bent, the tread A can be folded along the sides of the leg and the folding operation is completed (see Figure #c4).

However, in order to open the main ladder, contrary to the above, first spread the tread A, then grasp the left and right leg rods and pull them outward to bring the side rods 5, 5 into a horizontal state. At this time, since the lower ends of the leg rods of the F par 13 come off by themselves, the lower ends of the front and rear leg rods are in a state where they can be separated. However, in the upper part of the front and rear leg rods, one of the movable rods 6 intervenes in the joining part 10 of the arm 9, so if you partially release the connection between the arm and the movable rod and spread one of the leg rods in that state, the front and rear legs will move. The rod is expanded into an inverted V-shape on the side using the connecting fitting 3 as a fulcrum.

When the front and rear leg levers open, the treadle A
is displaced in the horizontal direction (from the vertical direction), and when the tension rod 4 becomes straight and the front and rear leg rods are fully opened, the tread A automatically moves to the upper surface of the upper horizontal rod, and the opening of the ladder legs is completed. (See Figure 1).

(Example) The four leg rods 1 arranged in front, rear, right and left are made of light metal plates bent into a substantially U-shape, and the upper ends of the front and rear leg rods 1 are fixed to the connecting fittings 3. It can be opened and closed freely. This connecting fitting 3 consists of a pair of halves 3a * 3a that rotate around a central pivot 2 as a fulcrum, and the upper end of the leg rod 1 is fitted onto the outside of the lower piece 3a' of each half. The piece 3a' and the leg rod 1 open and close at the same time. Further, a tension rod 4 is arranged between the upper parts of the front and rear leg rods 1, 1, and is bent at the center with an axis P as a fulcrum, and the opening and closing of the front and rear leg rods is linked to the tension rod 4.

Therefore, the inner ends of the left and right side rods 5,5 for footrest, whose bases are pivotally connected to the upper, middle, and lower parts of the left and right leg rods 1,1, are disposed parallel to the left and right leg rods, and at the intermediate portions. It is pivotally connected to a movable rod 6 located therein. In other words, the horizontal rods 5 and 5 have a U-shaped cross section,
The septum 5a at the inner end is superimposed on the front and rear of the intermediate piece 6a attached to the outside of the movable rod, and the septum 5& is pivotally attached to the movable rod 6 via the intermediate piece 6a by a pin g. The lower ends of the movable rods 6 are left and right support rods 7, 7 whose bases are pivotally connected to the lower ends of the left and right leg rods 1, 1.
It is inserted into the guide frame 8 at the upper end, and the left and right leg rods 1.
1 is opened and the horizontal rod 5 is in a horizontal state, the upper surface of the guide frame 8 faces the lower surface of the lower horizontal rod. And movable rod 6
The upper end of the upper horizontal rods 5 and 5 also protrudes slightly upwards, and the upper end of one movable rod 6 is attached to the upper end of the other movable rod 6.
An arm 9 forming a joining part 10 in which the upper end protrusion intervenes.
One end of the arm is pivoted, and a footboard A is attached to the other end of the arm. The tread A is a bendable left and right side plate 11.1.
1 and a middle plate 12, the bottom of the middle plate 12 is pivotally mounted eccentrically to the other end of the arm 9.

Further, a hook-shaped stopper 13 is fixed to one of the front and rear left and right support rods 7, 7 toward the other support rod, so that the lower part of the other leg rod is engaged with this stopper when folded. Also, a grip band 14 for use when folding is attached to the outer side of the leg rod.

(Effect of the invention) The effects of this invention are as follows.

α) By bending the tension rod 4, the front and rear leg rods 1, 1 can approach the connecting metal fitting 3 at the upper end as a fulcrum, so of course it is possible to change the legs from an inverted V-shaped state to a flat state.
When the left and right horizontal rods 5 are turned upward along with the movement of the movable rod 6, the left and right leg rods can be brought closer to each other in the width direction, so that the entire device can be folded back and forth and left and right into a compact size.

(2) The tread A, which is composed of the left and right side plates 11, 11 and the middle plate 12, has a sufficient width when unfolded, so you can ensure safety when working on a ladder, and the middle plate 1 is attached to the end of the arm 9.
2 are pivotally mounted eccentrically, so that the entire footboard moves vertically when folded in the front-rear direction, and as a result, the leg rods 1 can be folded in the width direction. By bending the left and right side plates to the outside of the upper ends of the folded leg rods, the entire ladder has a highly focused appearance, which is convenient for transportation and storage without taking up much space.

(3) Since the constituent members organically interlock, such as the tread A automatically moving from the horizontal direction to the vertical direction when folding, there is no waste in movement, and the opening and folding operations can be performed quickly.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing the book ladder in an open state, Fig. 2 is a top perspective view of the ladder showing a state in which it is folded in the front-rear direction, and Fig. 3 is a front view of the ladder showing the process of folding in the width direction. FIG. 4 is a perspective view of the ladder in a completely folded state, and FIG. 5 is a partial sectional view showing a state in which the lower part of the other leg is engaged with the stopper. 1...Leg rod, 2...Pivot, 3...Connection fittings, 4...Tension rod, 5...Horizontal rod,
6... Movable rod, 7... Support rod, 8...
Guide frame, 9...Arm, 10...Joining portion, 11...Side plate, 12...Middle plate A...Tread plate, 13...Stopper, 14...Gripping band.

Claims (1)

[Claims] Four leg rods 1 are provided in front, rear, left and right, and the upper ends of the leg rods 1, 1 are fixed to a connecting fitting 3 that mutually opens and closes with a pivot 2 as a fulcrum, and the front and rear legs are connected to each other. A bendable tension rod 4 is arranged between the rods, and the base is connected to the left and right leg rods 1 and 1.
The inner ends of the left and right transverse rods 5, 5, which are pivotally connected to the upper, middle, and lower parts of the is inserted into the guide frame 8 at the upper end of the left and right support rods 7, which are pivoted to the lower ends of the left and right leg rods 1, 1, and the upper end of one movable rod 6 slightly protrudes from the upper left and right horizontal rods 5, 5. One end of an arm 9 forming a joining part 10 in which the upper end of the other movable rod 6 intervenes is pivotally attached to the bottom of the middle plate 12 of the tread A with the left and right side plates 11 bendable at the other end of the arm. Furthermore, a stopper 13 that locks the lower end of the other leg rod 1, 1 when folded is fixed to one of the support rods 7, 7, and a grip band 14 is attached to the appropriate position of the leg rod 1, 1. A folding ladder that is installed.