CN100519982C

CN100519982C - Extension ladder

Info

Publication number: CN100519982C
Application number: CNB2005100769429A
Authority: CN
Inventors: 藤本祐司; 中村泰隆
Original assignee: AROKU INYASU Co Ltd
Current assignee: AROKU INYASU Co Ltd
Priority date: 2004-06-10
Filing date: 2005-06-09
Publication date: 2009-07-29
Anticipated expiration: 2025-06-09
Also published as: JP2005350938A; CN1707063A

Abstract

The invention provides an extendable ladder which achieves smooth rotation of a plastic pulley as a pulley unit main body, leading to light handling of an elevation handling rope, and reduced abrasion on an inner periphery of the pulley making sliding contact with a support shaft, to thereby extend the usable life of the pulley. The extendable ladder is formed of a lower-stage ladder 1, an upper-stage ladder 2 vertically movably engaging with the lower-stage ladder 1, and the elevation handling rope 3 mounted on the ladders 1, 2 via the pulley units, and functions to vertically move the upper-stage ladder 2 along the lower-stage ladder 1 by handling the elevation handling rope 3. Herein each pulley unit is formed of the plastic pulley 6 axially supported by the support shaft 5 on a mounting bracket 4, and comprised of a bearing 7 interposed between the pulley 6 and the support shaft 5.

Description

Extension ladder

Technical field

The present invention relates to a kind of extension ladder, this extension ladder is used for operator's lifting of high-rise working etc., the invention particularly relates to upper ladder is carried out telescopic lifting with respect to lower ladder extension ladder.

Background technology

As described in the open communique of Japanese Utility Model real fair 7-4318 number (patent documentation 1), extension ladder involved in the present invention is by lower ladder, upper ladder and descending operation rope constitute, wherein, upper ladder is fastened on this lower ladder, and its free lifting relatively, the descending operation rope across and be installed on these two ladders, can make upper ladder carry out telescopic lifting by operation descending operation rope along lower ladder, the descending operation rope is installed between the coaster, and above-mentioned coaster is set at for example upper end of lower ladder and the bottom of upper ladder respectively.And, shown in symbol 10 in the accompanying drawing 6, coaster is to be embedded metal system bolsters 5 and constituted by plastic pulley 6, and pulley 6 relative metal system bolsters 5 rotate freely, this bolster 5 is installed in metal installation with on the bracket 4, installs to be installed on the side frame of ladder with bracket 4.

Summary of the invention

In the extension ladder as patent documentation 1 described prior art, because forming the plastic pulley 6 of the main body of coaster directly is enclosed within on the metal bolster 5, so exist following problem, promptly, though the sliding of plastic material is good, but because the friction between pulley and the bolster 5, pulley can not rotate smoothly, so that in any case the operation of descending operation rope all becomes is very heavy, in addition, be worn easily with the wheel hub inner peripheral surface of the pulley 6 of bolster 5 mutual sliding-contacts, when these wearing and tearing increase, pulley 6 will produce and rock and influence rotation, and shorten the application life of pulley 6.

In view of above-mentioned problem, the purpose of this invention is to provide a kind of extension ladder with following feature, promptly, the rotation of the plastics system pulley that forms the coaster main body is become along sliding and making the operation of descending operation rope become light, simultaneously, can alleviate the wearing and tearing with the inner peripheral surface of the pulley of bolster sliding-contact, prolong the application life of pulley.

The reference symbol of additional aftermentioned embodiment describes the mode that is used to solve above-mentioned problem, that is, in technical scheme 1 of the present invention, the structure of described extension ladder comprises: lower ladder 1; Be fastened on the upper ladder 2 on the lower ladder 1, upper ladder 2 relative lower ladder 1 free liftings; Be installed in descending operation rope 3 on these two ladders 1,2 across these two ladders 1,2 and by means of coaster, can make upper ladder 2 carry out telescopic lifting by operation descending operation rope 3 along lower ladder 1, it is characterized in that: above-mentioned coaster comprises plastic pulley 6, this pulley 6 is propped up in for example steely installation by bolster 5 pivots and is folded with bearing 7 with on the bracket 4 between this pulley 6 and bolster 5.

The reference symbol of additional aftermentioned embodiment, the invention effect that above-mentioned settling mode is produced describes, promptly, according to technical scheme 1 of the present invention, because coaster is folded with bearing between pulley 6 and bolster 5, so the rotation of pulley 6 becomes along sliding, thereby the operation of descending operation rope becomes very light, particularly can carry out the stretched operation of upper ladder 2 like a cork.In addition owing to be folded with bearing 7, thus frayed hardly with the interior perimembranous of the pulley 6 of bolster 5 sliding-contacts, thus can prolong application life of pulley 6.

Description of drawings

Fig. 1 is the lateral view of expression extension ladder of the present invention.

Fig. 2 (a) is arranged on the front view of the coaster on the upper end of lower ladder of extension ladder shown in Figure 1, (b) is the transverse sectional view of this coaster.

Fig. 3 (a) is arranged on the front view of the coaster on the lower side of upper ladder of extension ladder shown in Figure 1, (b) is the longitudinal sectional view of this coaster.

Fig. 4 (a) and (b) be the expression another extension ladder of the present invention lateral view.

Fig. 5 is arranged on the transverse sectional view of the coaster on the extension ladder shown in Fig. 4 (a) and (b).

Fig. 6 is the transverse sectional view of coaster that is used for the prior art of extension ladder.

The specific embodiment

At first, describe from the unitary construction of extension ladder shown in Figure 1, this extension ladder is made of lower ladder 1, upper ladder 2 and descending operation rope 3, wherein, upper ladder 1 is fastened on this lower ladder 1, and its free lifting relatively, descending operation rope 3 is installed in up and down on two ladders 1,2 across two ladders 1,2 up and down and by slidinjg board A, B, can make upper ladder 2 carry out telescopic lifting along lower ladder 1 by operation descending operation rope 3.And be provided with slidinjg board A in the upper end of lower ladder 1, be provided with coaster B in the lower side (than high position, top, lower end) of upper ladder 2.

As (a) of Fig. 2 with (b), slidinjg board A comprises plastic pulley 6, and this pulley 6 is propped up in that for example steely installation is with on the bracket 4 by bolster 5 pivots, and bolster 5 is made of for example rivet, is folded with bearing 7 between the wheel hub 6a of this pulley 6 and bolster 5.Shown in Fig. 2 (b), the installation of this slidinjg board A is fixed on the side frame 1a of lower ladder 1 by rivet 12 with bracket 4, and protrudes to upper ladder 2 sides.

As Fig. 3 (a) with (b), coaster B is and the slidinjg board A identical construction, is made of plastic pulley 6, and this pulley 6 is propped up in steely installation for example with on the bracket 4 by bolster 5 pivots, bolster 5 is made of for example rivet, is folded with bearing 7 between the wheel hub 6a of this pulley 6 and bolster 5.The installation of this coaster B is fixed on the side frame 2a of the upper ladder 2 shown in Fig. 2 (b) by rivet (not shown) with bracket 4.

After the locking bar (omit diagram) that one end of descending operation rope 3 is connected the slidinjg board A of lower ladder 1 side is gone up, make its pulley 6 of walking around the slidinjg board A of lower ladder 1 side successively from the pulley 6 of the coaster B of upper ladder 2 sides, and the other end of this rope is fixed on the installation of coaster B with on the bracket 4.Therefore, under the state that makes lower ladder 1 ground connection, when the operation part 3a of stretched operation descending operation rope 3, upper ladder 2 stretches and rises, and the tensile force by releasing operation part 3a, upper ladder 2 is shunk and is descended.

Like this, because at this moment each slidinjg board A, B are folded with bearing 7 between the wheel hub 6a of pulley 6 and bolster 5, so the rotation of pulley 6 becomes along sliding, thereby the operation of descending operation rope becomes very light, particularly can carry out the stretched operation of upper ladder 2 like a cork.In addition, establish bearing 7, make and to wear and tear hardly, thereby can prolong application life of pulley 6 with the interior perimembranous of the wheel hub 6a of the pulley 6 of bolster 5 mutual sliding-contacts by folder.

(a) of Fig. 4 and (b) expression be a little dissimilar extension ladder with extension ladder shown in Figure 1.Extension ladder with regard to Fig. 4 (a), among carrying out the upper ladder 2 of lifting in lower ladder 1 with along this lower ladder 1, the coaster C, the D that protrude to upper ladder 2 sides are set respectively on the upper and lower end of lower ladder 1, and at a pair of middle coaster E of the lower side desired area upper edge of upper ladder 2 upper and lower settings, F.As shown in Figure 5, each coaster C, D, E, F are made of plastic pulley 6, and this pulley 6 is propped up in that for example steely installation is with on the bracket 4 by bolster 5 pivots, and bolster 5 is made of for example rivet, are folded with bearing 7 between the wheel hub 6a of this pulley 6 and bolster 5.

The upper end of descending operation rope 3 is connected on the locking bar (omitting diagram) of the coaster C of the upper end side that is positioned at lower ladder 1, and rope 3 is walked around in turn coaster F in the middle of the bottom of the lower end side coaster D of upper end side coaster C, lower ladder 1 of coaster E in the middle of the upside of upper ladder 2, lower ladder 1 and upper ladder 2, afterwards, the bottom of this rope 3 is connected the installation of lower end side coaster D of lower ladder 1 with on the bracket 4.Therefore, the same with the extension ladder of Fig. 1, under the state that makes lower ladder 1 ground connection, when the operation part 3a of stretched operation descending operation rope 3, upper ladder 2 stretches and rises, and the tensile force by releasing operation part 3a, upper ladder 2 is shunk and is descended.

In the extension ladder shown in Fig. 4 (b), be provided with coaster G in the upper end of lower ladder 1, it is protruded to upper ladder 2 sides, be fixed in a end under the state on the lower end desired area of upper ladder 2 descending operation rope 3, descending operation rope 3 is walked around the pulley 6 of coaster G, make the other end hang.As shown in Figure 5, this coaster G is made of the plastic pulley 6 that props up by 5 pivots of bolster on installing with bracket 4, and is folded with bearing 7 between the wheel hub 6a of this pulley 6 and bolster 5.Therefore, under the state that makes lower ladder 1 ground connection, if the operation part 3a of stretched operation descending operation rope 3, then upper ladder 2 rising that will stretch, and the tensile force by releasing operation part 3a, upper ladder 2 will be shunk decline.

As mentioned above, because Fig. 4 (a) and (b) shown in each coaster C～G of extension ladder between pulley 6 and bolster 5, be folded with bearing 7, so the rotation of pulley 6 becomes along sliding, thereby the operation of descending operation rope becomes very light, particularly can carry out the stretched operation of upper ladder 2 like a cork.In addition, establish bearing 7, make and to wear and tear hardly, thereby can prolong application life of pulley 6 with the interior perimembranous of the wheel hub 6a of the pulley 6 of bolster 5 mutual sliding-contacts by folder.

Claims

1. extension ladder, its formation comprises lower ladder, upper ladder and descending operation rope, wherein, the upper ladder lifting is fastened on the lower ladder freely, the descending operation rope is installed on these two ladders across these two ladders and by means of coaster, can make upper ladder carry out telescopic lifting by operation descending operation rope, it is characterized in that along lower ladder:

Above-mentioned coaster comprises plastic pulley, and this pulley is propped up on installing with bracket by the bolster pivot, is folded with bearing between this pulley and bolster.