JP2828620B2 - Tripod stepladder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tripod in which the upper end of a ladder-like leg opened in a C-shape and the upper end of a single leg are openably and closably connected.

[0002]

2. Description of the Related Art Unlike a quadruple stepladder, this type of tripod is a three-point support, so that it can be stably stood even if the supporting surface is not flat and obstacles are complicated. Even if it is complicated, the rear leg can be set up between those obstacles, so that it is widely used for garden tree pruning and the like.

[0003] Conventional tripod stepladder is, for example, Japanese Utility Model 5-22
As disclosed in Japanese Patent No. 639, as an adjusting device for arbitrarily adjusting the degree of opening of the support legs with respect to the ladder-like legs, one end of the rope is connected to the ladder-like legs, and the other end of the rope is connected. The ladder-shaped leg and the leg are opened by opening the ladder-shaped leg and the leg at an appropriate opening and pulling the other end of the rope. Is known to prevent it from opening further. A return restricting body that cuts into the inserted rope to prevent sliding in the return direction,
A spring for urging the return restricting body in the biting direction, and a release operation unit for moving the return restricting body in a direction for releasing the biting are provided.

According to this type of tripod, if the ladder-like leg and the pedestal are opened at an appropriate opening and installed, the ladder-like leg and the pedestal will not open further from that state. The ground contact portion at the lower end of the support leg slides, and the ladder-like leg and the support leg are unexpectedly opened, so that the tripod can be reliably prevented from falling.

[0005]

However, in the tripod with the configuration disclosed in the above publication, there is no means for preventing the ladder-like leg and the supporting leg from moving in the closing direction from the installed state. There is a problem that such a situation may occur. Referring to FIG.
As shown in FIG. 8A, a person climbs on the ladder-like leg 32 of the tripod 31. As shown in FIG. 8B, the entire center of gravity of the person and the tripod-like leg 31 is the ladder-like leg. When the ladder-like leg 32 moves forward from the lower end of the ladder 32 and rises forward, the lower end of the support leg 33 rises, and the support leg 33 rotates in the closing direction as indicated by the arrow. On the other hand, the person on the ladder-like leg 32 falls down backward (front side) as it is, so as to balance and move the center of gravity forward (rear side) as shown in FIG. Then, since the support leg 33 is already almost closed, FIG.
As shown in (d), the tripod step 31 falls to the rear side.

SUMMARY OF THE INVENTION In view of the above-mentioned conventional problems, the present invention has a risk that even if the entire center of gravity temporarily moves to the front side from the lower end of the ladder-like leg in a state where a person climbs, the leg does not close and may fall. The aim is not to propose a tripod.

[0007]

According to the present invention, there is provided a ladder having a front-side open-shaped ladder. When the support leg 3 is opened beyond a predetermined angle with respect to the ladder-like leg 2 in a tripod stepladder 1 in which the upper end of the leg-like leg 2 and the upper end of one rear leg 3 are openably and closably connected. Leg closing means 10, 21 to 21 for preventing the support leg 3 from closing at a predetermined angle or less and allowing at least a certain range of movement in the direction in which the support leg 3 is opened.
This configuration adopts a configuration in which 30 is disposed near the upper end of the ladder-like leg 2.

[0008] In the second aspect, the predetermined angle is:
The configuration according to claim 1, wherein an angle of the ladder-like leg 2 with respect to the horizontal plane when the tripod stepladder 1 is installed on the horizontal plane is set to be about 75 ° to about 80 °.

According to a third aspect of the present invention, there is provided a ladder-like leg 2.
A receiving plate 9 is provided at the upper end of the supporting leg 3 so as to face the upper end of the support leg 3. An L-shaped leg closing preventing piece 10 extending downward and extending rearward from the lower end is provided on the rear surface of the receiving plate 9 around the axis in the front-rear direction. The structure according to claim 1 or 2, wherein the rear end (10a) of the leg closing prevention piece (10) is rotatably mounted to engage with the upper end of the leg (3) to prevent the leg (3) from closing at a predetermined angle or less. Is adopted.

[0010] According to a fourth aspect of the present invention, the leg closing prevention piece 1 is provided.
The configuration according to claim 3 is adopted in which both side edges 13a are inclined or curved toward the rear end 10a so that the rear extension portion 13 of the zero is tapered toward the rear end 10a.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A tripod stepladder according to an embodiment of the present invention will be described below with reference to FIGS.

First, the overall configuration of a tripod stepladder will be described with reference to FIGS. 1 and 2. Reference numeral 1 denotes a tripod stepladder, which is a ladder-shaped leg body 2 opened in a front C-shape and one rear stepped leg. A support leg 3 is provided, and their upper ends are connected by a connecting portion 4 so as to be openable and closable. The ladder-like leg 2 is provided with side frames 2a arranged in a C shape on both sides and side frames 2 at appropriate intervals in the height direction.
A reinforcing member 2c is provided, which is constituted by a step bar 2b erected between a and 2a, and in a wide lower half portion, both sides of the step bar 2b are connected to each other in the vertical direction to reinforce each other. Further, a reinforcing member 2d is provided in a triangular shape between both end portions of the lowermost step bar 2b and a lower end portion of the side frame 2a. Further, a holding fitting 5 for fitting and holding the leg 3 in a closed state is attached to a rear surface of an appropriate step bar 2b located at a lower portion. On the other hand, an adjusting leg 3a for adjusting the length is provided at a lower portion of the supporting leg 3.
Is configured to be detachably attached, adjusted to an arbitrary length, and locked by the locking pin 3b.

A tripod 3 for the ladder-like leg 2 is located at a suitable height from the lower end where the tripod step 1 can be easily operated with the tripod 1 standing.
Opening adjustment means 6 for arbitrarily adjusting and setting the opening of
Are arranged. The opening degree adjusting means 6 has the same configuration as that of the conventional example, and includes a rope 7 having one end connected to the ladder-like leg 2 side and a return regulating means 8 mounted on the supporting leg 3 side and through which the other end side of the rope 7 is inserted. With the ladder-like leg 2 and the supporting leg 3 opened and set to an appropriate opening, the other end of the rope 7 is pulled to further open the ladder-like leg 2 and the supporting leg 3. It is configured to prevent

As shown in FIG. 3, the connecting portion 4 at the upper end of the tripod step 1 is provided with a receiving plate 9 opposed to the upper end of the supporting leg 3, and extends downward on the rear surface of the receiving plate 9 to extend downward. An L-shaped leg-preventing piece 10 extending rearward from the base is rotatably mounted on a pivot pin 11 about a longitudinal axis, and a rear end 10 a of this leg-preventing piece 10 is engaged with the upper end of the leg 3. Joint leg 3
Is prevented from closing below a predetermined angle.

As shown in detail in FIG. 4, the leg closing piece 10 comprises a vertical portion 12 extending vertically and a rear extending portion 13 extending rearward from the lower end thereof, and the rear extending portion 13 has a rear end 10a. The two side edges 13a are curved so as to taper toward. However, it may be inclined instead of curved. A pin hole 14 that fits into the pivot pin 11 is formed at the upper end of the vertical portion 12. In addition, the vertical portion 12
A reinforcing rib 15 is bulged at the center in the width direction over the rear extension 13 and a triangular shape is formed on both sides of the corners of the vertical portion 12 and the rear extension 13 to increase the rigidity. Are formed. The length of the rear extension 13 is set such that the rear end 10a engages with the support leg 3 in a state where the angle between the ladder-like leg 2 and the support leg 3 is a predetermined angle. The predetermined angle is a tripod stepladder 1
Is set so that the inclination angle α (see FIG. 1) of the ladder-like legs 2 with respect to the horizontal plane is 75 ° to 80 ° when the ladder-like legs 2 are installed on the horizontal plane.

At the time of using the tripod stepladder 1 having the above-described configuration, the return regulating means 8 of the opening degree adjusting means 6 is released from the state in which the supporting legs 3 are held by the holding fittings 5 of the ladder-like leg 2 and are closed. After loosening the rope 7, the leg 3 is opened. Then, when the opening degree of the ladder-like leg 2 and the support leg 3 exceeds the above-mentioned predetermined angle, the leg closing prevention piece 10 rotates around the pivot support pin 11 by its own weight and assumes a hanging posture, and the rear end 10 a
Can be engaged with the support leg 3, preventing the support leg 3 from closing at a predetermined angle or less, and allowing the support leg 3 to move in the opening direction. Then, the leg 3 is further opened to a required angle, and the tripod 1 is set at a desired position as shown in FIG. Then, the rope 3 is pulled to prevent the leg 3 from being further opened by the degree-of-opening adjusting means 6 and is adjusted to an appropriate degree of opening. The ladder-like leg 2 or the ground contact portion at the lower end of the leg 3 slides, and the ladder It is possible to reliably prevent the tripod 1 from tipping over due to the unexpected opening of the leg 2 and the support 3.

After the tripod stepladder 1 is installed in this manner, FIG.
As shown in (a), a person climbs the ladder-like leg 2 to perform a required operation. During this operation, the center of gravity of the person and the tripod step 1 is moved forward from the lower end of the ladder-like leg 2, and the ladder-like leg 2 is turned forward as shown in FIG. Even if the lower end of the support leg 3 rises and the lower end of the support leg 3 rises, when the support leg 3 is closed from the state shown by the imaginary line to a predetermined angle at the position of the solid line, the leg closing prevention piece 10 prevents the leg from closing below the angle. On the other hand, since the person on the ladder-like leg 2 falls backward (front side) as it is, if the balance is moved and the center of gravity is moved forward (rear side), the support leg 3 is maintained in an open state. When the ladder-like leg 2 assumes a posture inclined rearward in the retracted state,
The state is restored to (a), and it is possible to prevent the support leg 3 from closing and falling backward as in the related art. Even in the state restored in this manner, the inclination angle of the ladder-like leg 2 is about 75 to about 8
Since it is 0 °, a stable state of the tripod stepladder 1 is ensured.

When the use of the tripod leg 1 is completed, the tripod stepladder 1 is first tilted in the left-right direction. Then, as shown in FIG. 6, even when the tripod step 1 as a whole is tilted, the leg closing prevention piece 10 relatively rotates around the pivot pin 11 by its own weight and maintains its hanging posture. The engagement positional relationship between the end 10a and the support leg 3 is released, and the support leg 3 can be closed. If the rope 7 is adjusted to an appropriate opening as described above, it can be used as it is. Further, when the support leg 3 is closed, the side edges 13a of the rear extension 13 of the leg closing prevention piece 10 are curved so as to be tapered. 10a and the support leg 3 can be disengaged, and as the support leg 3 is closed, the leg closing prevention piece 10 engages with the side edge of the support leg 3 and rotates toward the retracted position. Can be easily rotated to the non-engagement position.

In the above-described embodiment, a leg-preventing piece which is rotatable about the pivot pin 11 to be in a hanging position in which it can be engaged by its own weight, and which is moved to a non-engaged position by tilting the tripod stepladder 1. 10, the configuration of the leg closing prevention means is not limited to this, and various configuration examples will be described below with reference to FIG.

FIG. 7 (a) shows the ladder-like leg 2 pivoting between an upward retreating position shown by a virtual line along the side frame 2a and an engaging position shown by a solid line engageable with the support leg 3. A free leg closing prevention lever 21 is attached to the side frame 2a. When the support leg 3 is opened, it is brought into an engaging position by its own weight, and when disengaged, it is turned to a retracting position by an operation rope (not shown) or the like. ing. FIG. 7B shows a state in which the same leg closing prevention lever 22 as that of FIG.

FIG. 7C shows the ladder-like leg 2 pivoting between a downward retracted position shown by a virtual line along the side frame 2a and an engaging position shown by a solid line engageable with the support leg 3. A leg closing prevention lever 23, which is possible and constantly urged by an urging means (not shown) toward the engagement posture, is mounted on the side frame 2a. At the time of disengagement, the operation rope (not shown) or the like is used to rotate to the retracted posture. FIG. 7D shows a state in which the same leg closing prevention lever 24 as that of FIG. 7C is attached to the step 2b.

FIG. 7 (e) shows a ladder-like leg 2 and a leg 3 connected by a leg-closing prevention link means 25 comprising a pair of links 25a and 25b which are connected to bend upward. A long hole 25c is formed in a connection portion of the link 25b on the third side with the support leg 3. When the support leg 3 is opened to a predetermined angle, the leg closing preventing link means 25 extends linearly to prevent the support leg 3 from closing, and allows the support leg 3 to be further opened within an appropriate range by the elongated hole 25c. is there. When the support leg 3 is closed, an operation rope (not shown) or the like is used to bend the leg closing link means 25 upward. FIG. 7 (f) has a configuration similar to that of FIG. 7 (e), except that its bending direction is only reversed, and is composed of a pair of links 26a and 26b which are connected to bendable downward. This is provided with a leg closing link means 26. 26c is a slot corresponding to 25c,
Further, there is provided a means for constantly urging the leg closing link means 26 linearly.

FIG. 7 (g) shows a ladder-like leg 2 having a pair of links 27a and 27b which are connected to bendable upward and provided with a locking mechanism 27d at the link connecting portion. And the supporting leg 3. The leg closing link means 27 is a lock mechanism 27.
Except for d, it is the same as the leg closing link means 25 of FIG. 7 (e), and the operation is the same. 26c is a long hole corresponding to 25c. FIG. 7 (h) has the same configuration as that of FIG. 7 (g), except that its bending direction is reversed.
A pair of links 28 that are connected to bend downward.
a, 28b are provided. Reference numeral 28c denotes an elongated hole corresponding to 25c, and a means for constantly urging the leg closing preventing link means 28 linearly is provided.

FIG. 7 (i) shows that the ladder-like leg 2 and the supporting leg 3 are connected by a closing prevention spring means 29 composed of a tightly wound spring, and the supporting leg 3 is closed by the shape retaining force of the tightly wound spring. When the support leg 3 is closed, the support leg 3 is bent as shown by a broken line against a shape retaining force with an operation rope (not shown) or the like.

FIG. 7 (j) shows that the ladder-like leg 2 and the supporting leg 3 are provided with a pivoting means 30 for preventing the closing of the leg, which is provided with a rotating shaft with a locking device. The lock is configured to be released by an operation rope (not shown) or the like.

[0026]

According to the first aspect of the present invention, when the leg is opened beyond a predetermined angle with respect to the ladder-like leg, the leg is prevented from closing at a predetermined angle or less, and the leg is opened in the opening direction. Is located near the upper end of the ladder-like leg at least in the vicinity of the upper end of the ladder-like leg. Even if the body rises forward and the lower end of the limb rises, the leg can prevent the limb from closing at a predetermined angle, so that the person on the ladder-like leg balances the center of gravity. When the is moved to the rear side, it can be restored to the installed state again, and it is possible to prevent the support legs from closing and falling down to the rear side as in the related art, and to provide a tripod with high safety.

According to the second aspect, the predetermined angle is set such that when the tripod is set on a horizontal plane, the angle of the ladder-like leg with respect to the horizontal plane is about 75 ° to about 80 °. Therefore, a stable state can be ensured when the ladder-like leg is restored after standing up.

According to a third aspect of the present invention, a receiving plate is provided at the upper end of the ladder-like leg and opposed to the upper end of the supporting leg, and an L-shape extending downward and extending rearward from the lower end on the rear surface of the receiving plate. Is mounted so as to be rotatable around the axis in the front-rear direction, and the rear end of the leg-preventing piece is engaged with the upper end of the leg to prevent the leg from closing at a predetermined angle or less. By simply tilting the tripod in the left-right direction, the engagement positional relationship between the leg closing prevention piece and the support leg can be released, and the support leg can be easily closed.

According to the fourth aspect of the present invention, since both side edges of the rear extension of the leg closing preventing piece are inclined or curved so as to be tapered toward the rear end, the leg can be closed only by slightly tilting the tripod. The engagement between the rear end of the preventive piece and the support leg can be released, and the operation of rotating the leg preventive piece to the disengaged position by rotating the leg preventive piece toward the retreat position with closing the support leg can be performed. Easy to do.

[Brief description of the drawings]

FIG. 1 is an overall side view of an embodiment of a tripod according to the present invention.

FIG. 2 is an overall front view of the embodiment.

FIG. 3 shows a configuration of an upper end portion which is a main part of the embodiment,
(A) is a side view, (b) is a front view.

4 (a) is a front view, FIG. 4 (b) is a sectional view taken along the line AA of FIG. 4 (a), FIG. 4 (c) is a bottom view, and FIG. 4) is a sectional view taken along the line BB in FIG.

FIG. 5 is an explanatory diagram of the operation when the embodiment is used.

FIG. 6 is an explanatory diagram of an operation when the support leg is closed in the embodiment.

FIG. 7 is an explanatory diagram showing various configuration examples of a leg closing prevention means in another embodiment of a tripod according to the present invention.

FIG. 8 is an operation explanatory diagram of a problem at the time of use in a conventional tripod stepladder.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tripod stand 2 Ladder-shaped leg 3 Supporting leg 9 Receiving plate 10 Leg closing prevention piece (leg closing prevention means) 10a Rear end 12 Vertical part 13 Rear extension 13a Both side edges 21 Leg closing prevention lever (leg closing prevention means) 22 Leg closing prevention lever ( Leg closing prevention means) 23 Leg closing prevention lever (leg closing prevention means) 24 Leg closing prevention lever (leg closing prevention means) 25 Leg closing prevention link means (leg closing prevention means) 26 Leg closing prevention link means (leg closing prevention means) 27 Leg closing prevention link means (leg closing prevention) Means) 28 leg closing preventing link means (leg closing preventing means) 29 leg closing preventing spring means (leg closing preventing means) 30 leg closing preventing pivot means (leg closing preventing means)

Claims (4)

(57) [Claims] 1. A tripod in which an upper end of a front ladder-like leg opened in a C-shape and an upper end of one rear limb are openably and closably connected. Is provided near the upper end of the ladder-like leg, which prevents the support leg from closing below the predetermined angle when opened beyond a predetermined angle and allows at least a certain range of movement in the direction in which the support leg is opened. Tripod stepladder characterized by doing. 2. When the tripod is set on a horizontal plane, the angle of the ladder-like leg with respect to the horizontal plane is approximately 75.
The tripod stepladder according to claim 1, wherein the angle is set to be approximately 80 ° to approximately 80 °. 3. An upper end of the ladder-like leg is provided with a receiving plate facing the upper end of the supporting leg, and an L-shaped leg closing preventing piece extending downward and extending rearward from the lower end is provided on the rear surface of the receiving plate. And a rear end of the leg closing preventing piece is engaged with an upper end of the supporting leg to prevent the supporting leg from closing at a predetermined angle or less. The tripod stepladder according to 2. 4. The tripod according to claim 3, wherein both side edges thereof are inclined or curved toward the rear end so that the rear extension of the leg closing piece tapers toward the rear end. stepladder.