EP0822317A2 - Hochfeste Faltleiter - Google Patents

Hochfeste Faltleiter Download PDF

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Publication number
EP0822317A2
EP0822317A2 EP96630055A EP96630055A EP0822317A2 EP 0822317 A2 EP0822317 A2 EP 0822317A2 EP 96630055 A EP96630055 A EP 96630055A EP 96630055 A EP96630055 A EP 96630055A EP 0822317 A2 EP0822317 A2 EP 0822317A2
Authority
EP
European Patent Office
Prior art keywords
ladder
rung
upright
reinforcing
uprights
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP96630055A
Other languages
English (en)
French (fr)
Other versions
EP0822317A3 (de
Inventor
Ik Woo Lee
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
IG Corp Co Ltd
Original Assignee
IG Corp Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by IG Corp Co Ltd filed Critical IG Corp Co Ltd
Publication of EP0822317A2 publication Critical patent/EP0822317A2/de
Publication of EP0822317A3 publication Critical patent/EP0822317A3/de
Withdrawn legal-status Critical Current

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Classifications

    • E—FIXED CONSTRUCTIONS
    • E06—DOORS, WINDOWS, SHUTTERS, OR ROLLER BLINDS IN GENERAL; LADDERS
    • E06C—LADDERS
    • E06C1/00—Ladders in general
    • E06C1/02—Ladders in general with rigid longitudinal member or members
    • E06C1/38—Special constructions of ladders, e.g. ladders with more or less than two longitudinal members, ladders with movable rungs or other treads, longitudinally-foldable ladders
    • E06C1/383—Foldable ladders in which the longitudinal members are brought together on folding
    • E—FIXED CONSTRUCTIONS
    • E06—DOORS, WINDOWS, SHUTTERS, OR ROLLER BLINDS IN GENERAL; LADDERS
    • E06C—LADDERS
    • E06C7/00—Component parts, supporting parts, or accessories
    • E06C7/08—Special construction of longitudinal members, or rungs or other treads
    • E06C7/082—Connections between rungs or treads and longitudinal members
    • E06C7/085—Connections between rungs or treads and longitudinal members achieved by deforming the rung or the stile
    • E—FIXED CONSTRUCTIONS
    • E06—DOORS, WINDOWS, SHUTTERS, OR ROLLER BLINDS IN GENERAL; LADDERS
    • E06C—LADDERS
    • E06C1/00—Ladders in general
    • E06C1/02—Ladders in general with rigid longitudinal member or members
    • E06C1/32—Ladders with a strut which is formed as a ladder and can be secured in line with the ladder

Definitions

  • the present invention relates, in general, to high strength foldable ladders made of aluminum and, more particularly, to a structural improvement in such ladders for providing a reinforcing part to each hinged joint of a foldable ladder thereby improving the durability of the ladder.
  • U.S. Patent No. 4,947,959 disclosed an aluminum folding ladder.
  • the folding ladder disclosed in the above U.S. Patent comprises a plurality of ladder sections, which are pivotally connected together by means of hinged joints.
  • Each ladder section consists of two uprights, each of which is provided with at least one rung hole. If each upright has two or more rung holes, the rung holes are equally spaced.
  • Each ladder section also has at least one rung which is fitted in and held by the holes of the uprights.
  • Korean U.M. Laid-open Publication No. 95-6677 disclosed a foldable mechanism which can be preferably used with aluminum foldable ladders.
  • Fig. 1 is a perspective view of a typical aluminum foldable ladder.
  • the typical foldable ladder includes a plurality of ladder sections 1, which are pivotally connected together by means of hinged joints 2.
  • Each ladder section 1 consists of two uprights 11, each of which is provided with at least one rung hole 111.
  • Each ladder section 1 also has at least one rung 12 which is fitted in and held by the holes 111 of the uprights 11.
  • both ends of the rung 12 are fitted into the holes 111 of the uprights 11 so that they penetrate the holes 111.
  • the ends of the rung 12 are, thereafter, compressed so as to fix the rung 12 to the uprights 11.
  • two outer ladder sections 1 have a symmetric construction, while two intermediate ladder sections 1 have the same construction.
  • the above foldable ladder has a problem in that the above ladder is made of aluminum so that the uprights of the ladder may be easily deformed or unbalanced when the ladder is used for a lengthy period of time or is overloaded.
  • an object of the present invention to provide a high strength foldable ladder in which the above problems can be overcome and which is provided with inner and outer reinforcing parts on both side surfaces of each upright, the reinforcing parts being formed by axially extending each hinged joint to a predetermined length along an upright and being used for uniformly distributing the vertical or lateral load to all directions of the upright thus giving high strength to the ladder.
  • the present invention provides a foldable ladder with high strength comprising a plurality of ladder sections pivotally connected together by means of hinged joints, each ladder section having two uprights with respective rung holes and at least one rung fitted into and fixed to the rung holes of the uprights, further comprising inner and outer reinforcing parts provided on opposite side surfaces of each upright, respectively, the inner and outer reinforcing parts extending from each hinged joint to a predetermined length along each upright.
  • Fig. 2 is a perspective view of a foldable ladder in accordance with a preferred embodiment of the present invention.
  • the foldable ladder of this invention includes a plurality of ladder sections 1, which are pivotally connected together by means of hinged joints 2'.
  • Each ladder section 1 consists of two uprights 11, each of which is provided with at least one rung hole 111 (see Fig. 3). Each ladder section 1 also has at least one rung 12 which is fitted in and held by the holes 111 of the uprights 11.
  • the ladder sections 1 are made of aluminum, while the hinged joints 2' are formed of a high strength material such as stainless steel or high strength aluminum alloy.
  • the foldable ladder of this invention is invented according to the fact that the hinged joints are made of the high strength material. That is, the hinged joints 2' of the ladder of this invention longitudinally extend to a predetermined length along the respective uprights 11 differently from the typical joints 2 of Fig. 1, thus forming reinforcing parts 21.
  • each upright 11 Both side surfaces of each upright 11 are sided by the inner and outer reinforcing parts 21 as best seen in Figs. 4A and 4B. Due to the above reinforcing parts 21, the rungs 12 are more strongly held by the uprights 11 so that the strength of the ladder sections 1 is remarkably improved.
  • Fig. 3 is an exploded perspective view showing the reinforcing parts 21 of the foldable ladder of this invention.
  • the rung 12 is fixed to the uprights 11 by fitting the rung 12 into the holes 111 of the uprights 11 prior to compressing both ends of the rung 12.
  • a reinforcing hole 211 is formed on each reinforcing part 21 so that the reinforcing hole 211 is aligned with the rung hole 111 of the upright 11. Therefore, when the rung 12 is fixed to the uprights 11 of a ladder section 1 of this invention, the rung 12 passes through the reinforcing hole 211 of the inner reinforcing part 21 and the rung hole 111 of the upright 11 prior to penetrating the reinforcing hole 211 of the outer reinforcing part 21.
  • a reinforcing boss 212 is provided on the edge of the reinforcing hole 211 of each outer reinforcing part 21.
  • the ends of the rung 12 are curled around the reinforcing bosses 212 when the rung 12 is compressed outside the outer reinforcing parts 21.
  • the upright 11, rung 12 and reinforcing parts 21 are integrated into a single body. Therefore, the rung 12 is more strongly fixed to the uprights 11.
  • Figs. 4A and 4B are sectional views of the ladder of this invention taken along the lines A-A and B-B of Fig. 2, respectively.
  • Figs. 4A and 4B show, in detail, the ends of the rung 12, which are curled around and wrapped about the bosses 212 of the reinforcing holes 211 of the outer reinforcing parts 21.
  • the inside surfaces of the inner and outer reinforcing parts 21 are knurled to form a plurality of reinforcing protrusions 213.
  • the above reinforcing protrusions 213 made of stainless steel thus eat into the opposite side surfaces of the aluminum upright 11 when both ends of the rung 12 are curled around the reinforcing bosses 212 of the outer reinforcing parts 21.
  • the integration strength of the junctions between the upright 11 and the inner and outer reinforcing parts 21 is thus improved.
  • the present invention provides a high strength foldable ladder provided with reinforcing parts.
  • Each reinforcing part of the above ladder is formed by axially extending the high strength hinged joint along the aluminum upright to a predetermined length and is provided with a reinforcing hole, boss and protrusions, thus remarkably improving the strength of the ladder without using any separate reinforcing member. Due to the above reinforcing parts, the foldable ladder of this invention is not only free from deformation when it is used for a lengthy period of time or is overloaded, the ladder is also free from causing a safety accident during a work using the ladder.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Ladders (AREA)
EP96630055A 1996-08-01 1996-09-13 Hochfeste Faltleiter Withdrawn EP0822317A3 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
KR9632179 1996-08-01
KR1019960032179A KR100210012B1 (ko) 1996-08-01 1996-08-01 고강도 철첩식 사다리

Publications (2)

Publication Number Publication Date
EP0822317A2 true EP0822317A2 (de) 1998-02-04
EP0822317A3 EP0822317A3 (de) 1998-11-04

Family

ID=19468560

Family Applications (1)

Application Number Title Priority Date Filing Date
EP96630055A Withdrawn EP0822317A3 (de) 1996-08-01 1996-09-13 Hochfeste Faltleiter

Country Status (4)

Country Link
EP (1) EP0822317A3 (de)
KR (1) KR100210012B1 (de)
AU (1) AU723701B2 (de)
DE (1) DE822317T1 (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1096101A1 (de) * 1999-10-29 2001-05-02 KRAUSE-WERK GMBH & CO. KG Leitergelenk
EP1795696A2 (de) * 2005-07-12 2007-06-13 Salemo & Merca, LDA Leitergelenk

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR200463313Y1 (ko) * 2010-05-11 2012-10-30 한전케이피에스 주식회사 단도체 폴리머 애자 정비ㆍ점검용 사다리

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE382061C (de) * 1923-09-28 Fritz Haecker Verwandlungsleiter
US3349870A (en) * 1966-08-25 1967-10-31 Lieblein George Flatstep ladder
AU2252767A (en) * 1968-05-29 1969-12-04 Trimview Metal Products Proprietary Limited Ladders
DE1938696A1 (de) * 1969-07-30 1971-02-04 Helmut Hoffmann Zusammenklappbare Mehrzweckleiter
GB1599636A (en) * 1978-01-10 1981-10-07 Relton S N Ladders
US5279387A (en) * 1991-09-25 1994-01-18 Emerson Electric Co. Articulated ladder assembly
DE9320070U1 (de) * 1993-12-30 1994-03-24 Rauschenberger Metallwaren GmbH, 71679 Asperg Verbindung eines Leiterholmes mit einem Leitergelenk

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE390323B (sv) * 1969-07-30 1976-12-13 H Hoffmann Hopfellbar universalstege

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE382061C (de) * 1923-09-28 Fritz Haecker Verwandlungsleiter
US3349870A (en) * 1966-08-25 1967-10-31 Lieblein George Flatstep ladder
AU2252767A (en) * 1968-05-29 1969-12-04 Trimview Metal Products Proprietary Limited Ladders
DE1938696A1 (de) * 1969-07-30 1971-02-04 Helmut Hoffmann Zusammenklappbare Mehrzweckleiter
GB1599636A (en) * 1978-01-10 1981-10-07 Relton S N Ladders
US5279387A (en) * 1991-09-25 1994-01-18 Emerson Electric Co. Articulated ladder assembly
DE9320070U1 (de) * 1993-12-30 1994-03-24 Rauschenberger Metallwaren GmbH, 71679 Asperg Verbindung eines Leiterholmes mit einem Leitergelenk

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1096101A1 (de) * 1999-10-29 2001-05-02 KRAUSE-WERK GMBH & CO. KG Leitergelenk
EP1795696A2 (de) * 2005-07-12 2007-06-13 Salemo & Merca, LDA Leitergelenk
EP1795696A3 (de) * 2005-07-12 2010-03-17 Salemo & Merca, LDA Leitergelenk

Also Published As

Publication number Publication date
KR100210012B1 (ko) 1999-07-15
EP0822317A3 (de) 1998-11-04
DE822317T1 (de) 1998-11-19
KR19980013622A (ko) 1998-05-15
AU2867897A (en) 1998-02-05
AU723701B2 (en) 2000-09-07

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