JPS6237919Y2 - - Google Patents

Description

[Detailed description of the invention] This invention is a stepladder in which a pair of legs forming a ladder shape are pivotally connected to each other, and both legs extend vertically to form a ladder, and can also be used as a stepladder by facing each other. The present invention relates to an opening stop device that maintains the set state of both legs.

As shown in the drawing, this type of stepladder has a pair of left and right main rods 2, 2 arranged so that one is narrow and the other wide, and a plurality of step ladders 3 are placed at intervals between the two main rods 2, 2. The legs 1 are constructed in the form of a ladder, and connecting plates 4, 4 are attached to the tips of the narrow sides of the pair of legs 1, 1.
, and both connecting plates 4, 4 facing each other are pivotally connected.As shown in FIG. If it extends vertically and continuously, it can be used as a ladder as shown in Figure 2. However, in order to maintain the legs 1, 1 in the opened and extended states, an opening stop device is installed across the legs 1, 1. In the conventional locking device, a connecting arm 5 is pivotally attached to the main rod 2 of one leg 1, a pin 7 is provided protruding from the main rod 2 of the other leg 1, and the pin 7 is fitted into the connecting arm 5. It is constructed by drilling a round Daruma-shaped extraction hole 6, and when the connecting arm 5 is to be hung on the pin 7, the pin 7 is inserted into the large hole 6a of the extraction hole 6, and then the pin 7 is inserted into the small hole 6b. It is fine if it is fitted so that it will shift, but if it is simply fitted, the connecting arm 5 will come off from the pin 7 due to vibration or impact.
A means for preventing the connecting arm 5 from coming off is added to the opening stopping device.

This invention is an improvement of the above-mentioned means for preventing the connecting arm from coming off with a unique structure.When locking the connecting arm to the pin, the pin is simply inserted into the small hole rather than the large hole in the extraction hole of the connecting arm. The object of this invention is to be able to easily remove the connecting arm when it is removed, and to prevent the connecting arm from coming off even if it is subjected to vibration or impact during locking.

Therefore, the opening stop device according to this invention will be specifically explained using an example, as shown in Fig. 3.
Among the conventional locking devices described above, this locking fitting 8 formed of a coil spring having a special structure is fitted onto the pin 7. Before explaining the locking fitting 8 in detail, the connecting arm 5 and the pin 7 will be explained.The connecting arm 5 is made of a band-shaped plate, and has a large hole at its tip.
A and a small hole 6b are continuously drilled with the large hole 6a facing downward, that is, forming a Daruma shape, with a constriction 6c between the large hole 6a and the small hole 6b. . The pin 7 has a head 7a, a body 7b and a leg 7.
The head part 7a is larger than the diameter of the small hole 6b and smaller than the large hole 6a, the body part 7b is formed to be thinner than the small hole 6b, and the leg part 7c is thinner than the body part 7b and the leg part 1 is formed later. This is the part that is tightened to the main rod 2.

Therefore, the locking fitting 8 is formed by winding a steel wire into a coil, with the upper and lower wound steel wires overlapping each other, and the inner diameter is approximately the same as the diameter of the body portion 7b of the pin 7. is also good, but ideally body 7
It is not thicker than b, and the outer diameter is the small hole 6b of the extraction hole 6.
However, it is not preferable to make the inner diameter larger than the inner diameter of the small hole 6b. Furthermore, the height of the locking metal fitting 8 is determined by the height of the body 7 of the pin 7 crimped onto the main rod 2.
Since the bottom surface of b is in pressure contact with the main rod 2, it is formed to have a length slightly shorter than the height of the body 7b, that is, the height from the surface of the main rod 2 to the back surface of the head 7a. Assuming that the height of the body 7b is 5 mm, the ideal size is about 4.8 mm. Further, both ends 8a and 8b of the steel wire constituting the locking fitting 8 are bent inside the coil. Ideally, the bent state is such that both ends 8a and 8b extend parallel to the tangent to the body 7b, and the tip does not touch the outer peripheral surface of the body 7b, as shown in FIG. . In addition, both ends 8
As shown in FIGS. 7 and 8, there are cases in which the portions a and 8b are bent into a rolled-up state.

This idea has the above structure, with one main rod 2
The connecting arm 5 is pivotally attached to the pin 7, the locking metal fitting 8 is fitted to the body 7b of the pin 7, and then the main rod 2 is attached to the main rod 2 by crimping. Therefore, in order to prevent the legs 1, 1 from opening, first fit the pin 7 into the large hole 6a of the extraction hole 6, then press the connecting arm 5 downward, and the pin 7 will fit into the small hole 6b of the extraction hole 6. By pressing the connecting arm 5 upward from this state, the pin (7) moves into the large hole 6a, and the connecting arm 5 can be removed from the pin 7. The above operation is similar to the conventional one, but in the device according to the present invention, the locking fitting 8 is fitted to the pin 7, so when moving the pin 7 from the large hole 6a to the small hole 6b, the sixth As shown in the figure, the locking metal fitting 8 is compressed by the constricted portion 6c of the extraction hole 6 and deforms into an elliptical shape.
When the locking metal fitting 8 passes through the constricted portion 6c and fits into the small hole 6b, the locking metal fitting 8 returns to its original circular shape by a repulsive force. Moreover, when passing through the constriction part 6c, the ends 8a or 8b of the steel wire of the locking fitting 8 may accidentally touch the constriction part 6c.
Even though the end portions 8a and 8b are bent inside the coil, the end portions are opposite to the constriction portion 6c.
It is smoothly fitted into the small hole 6b without getting caught. Therefore, even if vibration or impact is applied to the leg body after the locking metal fitting 8 is fitted into the small hole 6b, the locking metal fitting 8 will not deform and come off from the small hole 6b, and the open and closed state will be ensured. to hold. However, connecting arm 5
If you apply a force to pull it out from the pin 7, the locking metal fitting 8
can be deformed and removed from the small hole 6b.

It should be noted that when the bent ends 8a and 8b of the locking metal fitting 8 are bent as shown in FIG. It engaged smoothly with little friction. However, when bent as shown in Figure 7, A-A shown in the diagram
When compression is applied from the direction, it is necessary to press with a strong force, and when it is applied from the B-B direction, engagement is performed with a weak compression force, resulting in different results depending on the directionality. When tightening the pin 7 to the leg 1, the locking fitting 8 is fitted to the body 7b of the pin 7, and the leg 7c is tightened with a punch from above with the pin head 7a facing down. In some cases, the end portion 8a of the locking fitting 8 may accidentally pinch the end portion 8b between the trunk portion 7b and the leg body 1.

In addition, if the height of the locking metal fitting 8 is low, the connecting arm 8
When the pin 7 engages perpendicularly to the pin 7, there is no problem, but when it engages at an angle, the locking fitting tilts due to the play within the pin, and the repulsive force of the spring decreases. Alternatively, the locking metal fitting may shift to one side of the pin and fit into the gap, making it impossible to obtain the function of the locking metal fitting. Therefore, it is necessary to fit the locking fitting into the pin with almost no play.

Note that when the aforementioned connecting arm 5 engages with the pin 7 at an angle, since the main rod 2 of the leg body 1 is inclined,
When used as a ladder as shown in Figure 2, the connecting arm 5 hangs down vertically, but since the pin 7 protrudes perpendicularly from the main rod 2, they are inclined toward each other and engage with each other. It is something to do.

As described above, the stepladder opening locking device according to this invention has a pin that engages with the Daruma-shaped hole in the connecting arm, which is made of a coil spring, and the wound steel wires of the coil spring are stacked on top of each other, and both ends are bent into the coil. This locking fitting is fitted with a locking fitting, and when stopping the legs from opening, it can be done by engaging a pin in the hole in the connecting arm, as in the conventional case. When this occurs, the locking metal fitting remains in its molded form without being compressed within the small hole of the extraction hole, so the connecting arm will not come off from the pin even if subjected to vibration or impact, making it secure. This provides a long-lasting opening-stopping effect. In addition, since both ends of the locking metal fitting are bent into the coil, the ends do not get caught in the constriction between the large hole and the small hole, allowing smooth insertion and removal into the small hole. It is something that can be done.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing a stepladder to which the locking device of this invention is attached, Fig. 2 is a front view showing the same state when used as a ladder, and Fig. 3 is an exploded view of the locking device of this invention. A perspective view, FIG. 4 is a vertical sectional view showing a state in which the connecting arm is engaged with the pin,
Figure 5 is a cross-sectional view of Figure 4, Figure 6 is a cross-sectional view showing the state when the locking metal fitting enters the small hole from the large hole, and Figures 7 and 8 show similar examples of the locking metal fitting. FIG. 1...Leg body, 2...Main rod, 3...Treadle, 5...
Connecting arm, 6... Extraction hole, 6a... Large hole, 6b... Small hole, 6c... Narrow portion, 7... Pin, 8... Locking metal fitting, 8a, 8b... Locking metal fitting end.

Claims (1)

[Scope of utility model registration request] A stepladder in which a pair of legs 1, 1 formed in the shape of a ladder are pivotally connected to each other, and both legs 1, 1 extend vertically to form a ladder and are opposed to each other to serve as a stepladder,
In the locking device configured by providing a Daruma-shaped extraction hole 6 in a connecting arm 5 pivotally supported on one leg 1 and providing a pin 7 into which the extraction hole 6 of the connecting arm fits in the other leg 1, the pin 7 is provided. and a locking metal fitting made of a coil spring having an outer diameter approximately the same as the inner diameter of the small hole 6b of the extraction hole 6, and having both ends of the steel wire bent inside the coil. 8. A stepladder opening stop device characterized by being fitted with a stepladder.