JPS6343353Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a connecting device for a stepladder.

As is well known, the front and rear legs of a stepladder are pivotally connected in order to facilitate storage and to enable the stepladder to be used as a ladder. When using it as a stepladder, open the front and rear legs at a specified angle and connect them with a connecting member to prevent them from opening. When using it as a ladder, rotate the front and rear legs so that they are in a straight line and connect both legs with the connecting member. They are connected and cannot be rotated.

From the standpoints of safety, operability, and cost, this connection using connection members must be able to prevent accidental disengagement, maintain a reliable and strong connection, and be able to be operated quickly and easily. figure,
Furthermore, it must have a simple structure.

However, conventional devices do not fully satisfy all of the above requirements, each having advantages and disadvantages.

Therefore, the applicant of the present application proposed a stepladder connecting device in Utility Model Application No. 57-28038, which has a simple structure, is easy to operate, and can reliably maintain the connection. That is, one end is rotatably pivoted to the front leg, and the other end is provided with an engagement recess that is a U-shaped notch that has an opening on the lower side in the rotational direction and penetrates in the rotational axis direction. When the engaging concave portion engages with the engaging protrusion provided on the rear leg using the connecting member, separation from each other is prevented by using a lock plate having a locking hole. However, the distance between the engagement recess, which is a U-shaped notch in the connecting member, and the opposite end of the pivot joint is often difficult to maintain, and because the distance between them is short, the strength is insufficient, and the space between them deforms when using the stepladder. A problem arose.

The present invention was developed in view of the above points, and has a simple structure, easy operation, and can maintain connection reliably.One end is pivoted and the other end has a U-shape to prevent opening. An object of the present invention is to provide a connecting device for a stepladder that does not cause deformation even if there is not a sufficient distance between the engaging recess and the opposite end of the pivot in a connecting member provided with a notched engaging recess. It is characterized by a connecting device that connects the front and rear legs of a stepladder whose front and rear legs are rotatably connected to each other and makes them unrotatable. The connecting member is pivotally connected to the connecting member so as to be freely movable, and the other end of the connecting member is provided with an engaging recess that has an opening on one side in the rotational direction and penetrates in the direction of the rotational axis, and can be freely engaged and detached from the engaging recess. An engagement protrusion to be engaged is provided on the other leg and protrudes perpendicularly to the rotation plane of the engagement recess, and a lock plate having a locking hole into which the engagement protrusion is loosely fitted is connected to the locking hole and the engagement recess. The plate is attached to the side of the engagement recess to close the opening by aligning the two legs, and the plate is swingably pressed toward the side of the engagement recess by an elastic member. The end of the lock plate that contacts when rotated and the tip of the engagement protrusion are formed so as to make tapered contact, and the reinforcing portal frame has an avoidance space that ensures rocking when the lock plate engages and disengages. is on the attached surface of the lock plate, and extends over both sides of the connecting member that is partially divided by the engaging recess.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

In FIGS. 1 and 2, reference numeral 1 denotes a stepladder that can also be used as a ladder, and the stepladder 1 has a front leg 2 and a rear leg 3 rotatably connected at one end with a pivot bracket 4. be. The front and rear legs 2 and 3 each have a pair of left and right side frames 5, and a ceiling 6 is constructed at the top of both side frames 5, with a predetermined interval in the middle of the side frame 5 in the longitudinal direction, and is not shown. A treadmill has been erected.

7 is a connecting member, and the connecting member 7 is connected to a first connecting plate 8.
and a second connecting plate 9, both connecting plates 8 and 9 are rotatably connected by a support shaft 10 to form one connecting member 7.
Configure. The second connecting plate 9 is formed to have an L-shaped cross section, and the first connecting plate 8 is brought into contact with the flange portion 11 of the second connecting plate 9, so that both the connecting plates 8 and 9 are kept in a straight line. That is, both connecting plates 8 and 9 are pivotally connected to each other so as to be rotatable only within a range of 180 degrees.

One end of the connecting member 7, that is, the end of the first connecting plate 8, is rotatable on a support shaft 12 protruding from the outer surface of the side frame 5 of one of the front and rear legs 2, 3, for example, the front leg 2. It is freely connected. The connecting member 7 is rotatable along the side surface of the side frame 5, and is attached to the support shaft 1 of the side frame 5.
2 and a support shaft 10 that connects the first and second connecting plates 8 and 9 have parallel axes, and the flange portion 11 of the second connecting plate 9 is located upward. Such connecting members 7 are provided on the left and right side frames 5 of the front leg 2, respectively.

An engagement recess 13 is provided at the other end of the connecting member 7, that is, at the end of the second connecting plate 9. This engagement recess 13 has an opening 14 on one side in the rotational direction of the connecting member 7, and is formed in a semicircular recess that penetrates in the direction of the support shaft 12. The opening 14 is located below the opposite side of the flange portion 11.

The side frame 5 of the rear leg 3 is provided with a first engagement protrusion 15 that detachably engages with the engagement recess 13. The engagement protrusion 15 is provided parallel to the support shaft 12 so as to protrude perpendicularly to the rotation plane of the engagement recess 13. Furthermore, a similar second engagement protrusion 16 is provided on the pivot fitting 4 of the rear leg 3.

A lock plate 17 is attached to the outer surface of the connecting member 7, and its details are shown in FIGS. 3 and 4. The lock plate 17 is provided with a locking hole 18 into which the locking protrusion 15 is loosely fitted, and the locking hole 18 and the locking recess 13 are attached concentrically. That is, this lock plate 17
The opening 14 of the engagement recess 13 is closed. The lock plate 17 is pivotally attached to a support shaft 19 protruding from the side surface of the second connecting plate 9 through a hole 20 so as to be swingable in the axial direction. This spindle 1
Reference numeral 9 is provided between the flange portion 11 and the engagement recess 13 and has an axis parallel to the engagement recess 13 . A spring 21 is fitted onto this support shaft 19, and the spring 21 connects the lock plate 17 to the second connecting plate 9.
It is pressed to the side. The upper end surface of the lock plate 17 is in contact with the flange portion 11, and this contact prevents the lock plate 17 from rotating around the support shaft 19.

The lower end of the lock plate 17 is bent outward to form a bent portion 22. This bent part 22
Further, an arc-shaped bulging portion 23 bulging outward is provided. This bulging portion 23 is connected to the support shaft 19 and the locking hole 1.
It is provided so that its axis lies on a line connecting the center points of 8. This bent portion 22 and bulging portion 23
As shown in FIG. 5, when the end of the lock plate 17 and the tip of the engagement protrusion 15 come into contact, the taper abuts and makes it easier to push the lock plate 17 outward. be.

24 is a reinforcing portal frame, and the engagement recess 13
Legs 25 are erected and fixed on both left and right sides of the second connecting plate 9, which is divided into parts by. Portal frame 2
Reference numeral 4 is formed by bending a band-shaped material, and its legs 25 are fixed to the connecting plate 9 by welding such as spot welding. Legs 25, 25 of portal frame 24
The distance between the lock plate 17 has a width that allows the lock plate 17 to swing, and the height thereof is such that when the engagement recess 13 engages the engagement protrusion 15, as shown in FIG. 17 swinging can be ensured and the engaging protrusion 1
5 is high enough to pass through.

Next, the effects of the embodiment of the present invention will be explained with reference to FIG.

When using the stepladder 1 as a stepladder, the front and rear legs 2 and 3 are opened at a predetermined angle as shown by the solid line in Figure 1, and the legs 2 and 3 are connected by a connecting member 7 to prevent them from opening. . During this connection work, as shown in FIGS. 5 and 6, the engagement recess 13
The connecting member 7 is rotated around the support shaft 12 so that the opening 14 and the first engaging protrusion 15 face each other. As a result of this rotation, the lower end of the lock plate 17 first collides with the tip of the engaging protrusion 15. During this collision, the bulging portion 23 of the bent portion 22 of the lock plate 17 and the tip of the engaging protrusion 15 come into contact. Since both are in taper contact, the lock plate 17 is connected to the spring 21.
The engaging protrusion 15 is guided into the locking hole 18 by being pushed outward in the axial direction of the support shaft 19 against the force. When the engagement protrusion 15 comes out into the locking hole 18, the lock plate 17 is pressed by the spring 21 and returns to its original state, and the engagement protrusion 15 and the engagement recess 13 are fitted together. The engagement protrusion 15 is then held in the engagement hole 18 of the lock plate 17 and cannot be removed from the opening 14 of the engagement recess 13 any longer. At this time, the bulging portion 23 serves to guide the engagement protrusion 15 to the locking hole 18 and also serves as a strength rib.

Thus, the front and rear legs 2, 3 are reliably and firmly connected with one touch by the connecting member 7, and are prevented from opening, and there is no possibility that the connecting member 7 will come off accidentally. Further, the force exerted on the connecting member 7 by the engaging protrusion 15 after the connection is received by a member between the engaging recess 13 and the opposite end of the connecting member 7, but this portion is absorbed by the portal frame 24. Since it is connected to the member on the pivoting side of the engagement recess 13 through, it can sufficiently withstand the applied force and will not be deformed.

To release the engagement between the engagement recess 13 and the engagement protrusion 15, simply lift the bent portion 22 of the lock plate 17 upward by hand, as shown by the phantom lines in Figure 6. This rotation releases the engagement protrusion 15 from the engagement hole 18, making it free to remove from the opening 14.

Next, when using the ladder as a ladder, the rear legs 3 are rotated 180 degrees to align the front and rear legs 2 and 3 as shown by the imaginary lines in FIGS. 1 and 2. After that, the engagement recess 13 of the connecting member 7 and the second engagement protrusion 1
6 are locked as described above.

In addition, when storing by folding, the pivot portions of the first connecting plate 8 and the second connecting plate 9 may be bent as shown by the imaginary line in FIG.

It should be noted that the present invention is not limited to the above embodiments, and the connecting member is not bendable.
It can also be a connecting rod for books. 7 and 8 show other embodiments of the lock plate and portal frame, and in the figures, the lower part of the lock plate 17' is bent outward to form a bent portion 22'. This is similar to the lock plate 17 described above, but the lock plate 17' has a locking hole 1.
A tongue piece 26 is protruded on the same inclined plane as the bent portion 22' on a line connecting the center of the support shaft 19 and the locking hole 18' on the inner side of the locking hole 8'. The tongue piece 26 is configured such that when the engagement recess 13 is engaged with the engagement protrusion 15 and the lock plate 17' is engaged with the engagement protrusion 15, a force in the opposite direction is applied to the connecting plate 9. When activated, it acts to sink into the engaging protrusion 15, and lock plate 1
This is preferable because it can prevent the engaging protrusion 15 of 7' from shifting outward in the axial direction. In addition, in the figure, 24a indicates a gate-shaped frame formed by bending a round bar material, and the leg portion 25
a is caulked to the connecting plate 9. Also the 9th
The figure and FIG. 10 are other embodiments of the portal frame,
24b is a portal frame made by bending and forming a band-shaped material,
Locking holes 27, 27 are provided in each leg portion 25b, 25b. The portal frame 24b is fixed to the connecting plate by inserting the locking pieces 28, 28 raised by the connecting plate 9 into the locking holes 27, 27 and bending them from the engaging recess 13 toward each end side. .
Furthermore, FIGS. 11 and 12 show other embodiments of the portal frame, and the portal frame 24c in this case is formed by bending a portion of the lower side of the connecting member in the rotation direction into a bulging shape. It is.

As described above, according to the present invention, since the lock plate having the locking hole prevents the engagement recess and the engagement protrusion provided at the opposite end of the connection member from separating, the connection member It is extremely safe as it reliably prevents its separation from external forces acting on it in any direction. In particular, even if the connecting member is in a substantially vertical position like a ladder, it is ensured that it will not come off. In addition, since the lock plate and the engagement protrusion are in tapered contact, simply by rotating the connecting member and causing it to collide with the engagement protrusion, the locking is performed with one touch, improving operability. It will be planned. Further, a reinforcing portal frame having an avoidance space for ensuring rocking when the lock plate is engaged and disengaged is provided on the attached surface of the lock plate and on both sides that are partially divided by the engagement recess. Even if there is not enough distance between the engagement recess and the opposite end of the coupling member, the force applied by the engagement protrusion to the opposite end of the engagement recess can be absorbed. This can also be done on the pivot side of the mating recess, and no deformation occurs during this time. In addition, the structure is extremely simple,
It has many practical effects, such as fewer failures, ease of manufacture, and cost reduction.

[Brief explanation of the drawing]

The figures show an embodiment of the invention, with Figure 1 being a side view;
Fig. 2 is a front view, Fig. 3 is a cross-sectional view of the main part, Fig. 4 is a side view of the main part, Figs. 5 and 6 are explanatory diagrams, and Figs. A diagram showing
Figure 7 is a sectional view of the main part, Figure 8 is a side view of the main part, and Figure 9 is a sectional view of the main part.
Figures 11 and 11 are side views of main parts, Figures 10 and 1.
2 shows bottom views of essential parts corresponding to FIGS. 9 and 11, respectively. 1... Stepladder, 2... Front legs, 3... Back legs, 7...
Connecting member, 13... engaging recess, 14... opening,
15, 16... Engaging protrusion, 17... Lock plate, 18... Locking hole, 21... Spring, 22
...Bending part, 24...Portal frame.

Claims (1)

[Scope of utility model registration request] In a connecting device that connects the front and rear legs of a stepladder in which the front and rear legs are rotatably connected to each other and makes them unrotatable, one end of the connecting member is rotatably connected to one leg, and the other end of the connecting member is rotatably connected. An engagement recess that has an opening on one side in the rotation direction and penetrates in the rotation axis direction is provided at the end, and an engagement protrusion that releasably engages with the engagement recess is located in the engagement recess. A lock plate is provided on the other leg and protrudes perpendicularly to the rotation plane, and has a locking hole into which the engaging protrusion is loosely fitted. The plate is attached to the side of the engaging recess, and is swingably pressed in the side direction of the engaging recess by an elastic member, and further includes a lock plate end that comes into contact when the connecting member is rotated to connect both legs. A reinforcing gate-shaped frame is formed on the attached surface of the lock plate and has an avoidance space that is formed so as to taper into contact with the tip of the engagement protrusion and ensures rocking when the lock plate is engaged and disengaged. A connecting device for a stepladder, characterized in that it is installed across both sides of a connecting member that is partially divided by the engaging recess.