JPH1181843A - Three-leg step-ladder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the use of a three-leg step-ladder even at stairs and slope and reduce weight and price thereof without impairing a function thereof by providing a support leg in a top part of a ladder body so as to open and close it and providing a fixing device of a guide part in which a leg slides and a semicircular curved leg in a lower end part of the ladder body to adjust the expansion and shrinkage of the leg in the direction of its height. SOLUTION: This three-leg step-ladder is constituted by a ladder body 1, a curved leg 2 which is inserted into guide parts 4, 4 provided in a lower part of the ladder body 1, and a support leg 3, and the curved leg 2 can be fixed at an arbitrary position by a fixing device 8. The ladder body 1 is provided with the framelike guide parts 4, 4 in lower end parts of longitudinal members 5, 5, and connection parts 20, 20 protrude from a top part toward a back side thereof. The curved leg 2 is curved like a semicircle toward above and is provided with a tooth shaped member 9 for regulating slide on a lower face thereof, and support bases 12, 12 which turn in the same direction as the direction of slide of the curved leg 2 by shaft parts 11, 11 are provided in both end parts of the curved leg 2. The support leg 3 which can adjust its expansion and shrinkage in the direction of height supports a connection rod 14 between connection parts 20 and 20 of the ladder body 1 and is opened and closed toward the back side of the ladder body 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tripod which can be stably used in a vertical state even on stairs or slopes.

[0002]

2. Description of the Related Art A tripod is mainly used at a high place in an agricultural workplace such as a construction site or an orchard, and as a conventional tripod, a ladder body 51 and a top of the ladder body 51 as shown in FIG. The one on which the supporting leg 53 is pivotally supported so as to be openable and closable on the back side of the step 52 is used. Further, as shown in FIG. 6, a stabilizing device is provided at the lower part of the folding ladder bodies 71, 71 as a stepladder for stably maintaining the scaffold in a vertical state even on stairs or on slopes. A semicircular curved leg 72 is slidably inserted, and the curved leg 72 is fixed at an arbitrary position.

[0003]

However, when a stepladder is used for mounting work such as lighting fixtures at a construction site or harvesting work in an orchard, the stepladder must be moved frequently, and it is necessary to consider carrying. It is desirable that the tripod is as light as possible. Although the tripod is lightweight, it is difficult to use it on stairs and slopes. In addition, the stepladder with a stabilizing device allows the worker to stably maintain the stepladder in a vertical state on stairs and slopes and perform work, but the weight is increased by a stabilizing device as compared with a general stepladder, and the burden on carrying is increased. And there is a concern that the work efficiency will decrease.

An object of the present invention is to solve the above-mentioned problems and to provide a lightweight and inexpensive tripod stepladder without impairing the function of the conventional tripod stepladder or the function of the stepladder.

[0005]

The ladder body comprises a ladder body, a semicircular curved leg provided at a lower portion of the ladder body, and a support leg attached to the top of the ladder body so as to be openable and closable. A guide part on which the leg slides and a fixing device for the curved leg are provided,
The support leg is capable of adjusting the expansion and contraction in the height direction.

[0006]

When the tripod stepladder of the present invention is used on a stair or a slope, the curved leg is released from the fixing device so that it can slide freely, the curved leg is grounded on the stair or the slope, and the step on the top of the ladder body is horizontal. And then fix it with a fixing device. In addition, the support angle and height of the support legs are adjusted to stably support the ladder body.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A tripod stepladder according to the present invention can be opened and closed at a ladder body 1, a semicircular curved leg 2 inserted into guides 4 and 4 provided at a lower portion of the ladder body 1, and a top of the ladder body 1. And a supporting leg 3 capable of adjusting the expansion and contraction in the height direction. The curved leg 2 is fixed at an arbitrary position by a fixing device 8.

As shown in FIG. 1, the ladder body 1 includes a plurality of horizontal members 6a,
Step 13 provided at the top between 6b, 6c and vertical members 5, 5
Frame members are provided at the lower ends of the vertical members 5, 5, and the connecting portions 20, 20 project from the tops of the vertical members 5, 5 toward the rear side. .

The curved leg 2 is curved upward in a semicircular shape,
The lower surface is provided with a tooth member 9 for restricting sliding, and both ends of the curved leg 2 are provided with support bases 12 and 12 which are rotated by shafts 11 and 11 in the same direction as the sliding direction of the curved leg 2. I have.

The supporting leg 3 is connected to a connecting rod 14 parallel to the step 13 of the ladder body 1, a cylindrical external supporting rod 15 extending downward from the center of the connecting rod 14, and loosely fitted inside the external supporting rod 15. The connecting rod 14 is pivotally supported between the connecting portions 20 of the ladder body 1 and opens and closes toward the rear side of the ladder body 1. At the lower end of the internal support rod 16, there is provided a support base 23 that rotates about the shaft 22, similarly to the curved leg 2.

As a means for adjusting the height of the support leg 3, as shown in FIG. 2, the external support rod 15 is provided with a plurality of insertion holes 17 at appropriate intervals in the longitudinal direction. An adjusting hole 18 that matches the insertion hole 17 is provided, and a stopper 19 is inserted into the matching insertion hole 17 and the adjusting hole 18 to adjust the height of the support leg 3. As shown in FIG. 3, in addition to the above, one insertion hole 17 is provided in the external support rod 15, and a plurality of adjustment holes 18 corresponding to the insertion hole 17 are provided in the internal support rod 16 at appropriate intervals in the longitudinal direction. It may be provided.

As shown in FIG. 4A, the fixing device 8 is pivotally supported by a fixing portion 24 attached to the center of the lowermost horizontal member 6c of the ladder body 1 and an arm portion 27 protruding from the fixing portion 24. A tooth profile provided on the lower end of the curved leg 2 shown in FIG. 4B at the tip of the tightening portion 26, which is constituted by a tightening portion 26 and a spring 28 pressing the tightening portion 26 toward the lower surface of the curved leg 2. An operating lever 25 is provided at the rear of the vehicle, including a fitting portion 10 that meshes with the member 9. By rotating the operation lever 25 in the vertical direction, the fitting portion 10 and the tooth-shaped member 9 of the curved leg 2 are fitted and removed. In addition to the above, the fixing device 8 includes a vertical member 5,
5 penetrate through bolt holes (not shown) in the guide portions 4 and 4 provided at the lower end of the curved leg 2 with bolts screwed into the respective bolt holes.
May be fixed.

It is desirable that a chain 21 be connected between the ladder body 1 and the support leg 3 so that the ladder body 1 and the support leg 3 are not opened at a certain angle or more.
If the connecting members 19 are connected, the stoppers 19 can be prevented from being lost. Further, instead of the chain 21, a link type may be used.

[0014]

According to the tripod with the above-described structure, the operator can stably and stably perform work on stairs and slopes, which was difficult with the conventional tripod. Compared with a stepladder having curved legs, the number of components is smaller and lighter, so that the burden of carrying is reduced even in work involving frequent movement, and work efficiency is improved. Also, it can be provided at low cost.

[Brief description of the drawings]

FIG. 1 is a perspective view of a tripod according to the present invention.

FIG. 2 is a perspective view showing an external support rod and an internal support rod of the present invention.

FIG. 3 is a perspective view showing an external support rod and an internal support rod of the present invention.

4A and 4B are a longitudinal sectional view of a fixing device used in the present invention and a front view showing a curved leg.

FIG. 5 is a perspective view showing a conventional tripod stepladder.

FIG. 6 is a perspective view showing a conventional stepladder with a stabilizer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ladder body 2 Curved leg 3 Support leg 4 Guide part 8 Fixing device

Claims (1)

[Claims] 1. A ladder body (1), a semicircular curved leg (2) provided at a lower portion of the ladder body (1), and a support leg (3) attached to the top of the ladder body (1) so as to be openable and closable. The ladder body (1) is provided with guide portions (4, 4) at the lower end portion on which the curved legs (2) slide, and a fixing device (8) for fixing the curved legs (2) in an appropriate position. The tripod is characterized in that the leg (3) can be adjusted to expand and contract in the height direction.