EP0000344B1 - Improvements in or relating to ladders - Google Patents

Improvements in or relating to ladders Download PDF

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Publication number
EP0000344B1
EP0000344B1 EP78100247A EP78100247A EP0000344B1 EP 0000344 B1 EP0000344 B1 EP 0000344B1 EP 78100247 A EP78100247 A EP 78100247A EP 78100247 A EP78100247 A EP 78100247A EP 0000344 B1 EP0000344 B1 EP 0000344B1
Authority
EP
European Patent Office
Prior art keywords
hollow
section
ladder
interlocked
stile
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.)
Expired
Application number
EP78100247A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0000344A1 (en
Inventor
Edwin John Bruton
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.)
Abru Aluminium Ltd
Original Assignee
Abru Aluminium 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 Abru Aluminium Ltd filed Critical Abru Aluminium Ltd
Publication of EP0000344A1 publication Critical patent/EP0000344A1/en
Application granted granted Critical
Publication of EP0000344B1 publication Critical patent/EP0000344B1/en
Expired legal-status Critical Current

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Classifications

    • 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
    • E06C1/04—Ladders for resting against objects, e.g. walls poles, trees
    • E06C1/08—Ladders for resting against objects, e.g. walls poles, trees multi-part
    • E06C1/12—Ladders for resting against objects, e.g. walls poles, trees multi-part extensible, e.g. telescopic

Definitions

  • the present invention relates to stiles and other components of ladders, as well as to ladders, especially extension ladders.
  • a stile for a ladder, extension ladder, steps or the like which stile comprises a hollow box section, characterised in that the hollow section comprises two interlocked elongate sections of steel of a thickness in the range of from 0:5 to 0.8 mm, which elongate sections are interlocked by having been longitudinally slid one inside the other and the hollow being filled with a synthetic plastics material foam.
  • a ladder, extension ladder, steps or the like which comprises one or more stite(s) in accordance with the first aspect of the present invention.
  • an extension ladder component which comprises two stiles, each stile comprising a hollow box section, characterised in that the hollow section comprising two interlocked elongate sections of steel of thickness in the range of from 0.5 to 0.8 mm, which elongate sections (2 and 3) are interlocked by having been longitudinally slid one inside the other and the hollow being filled with a synthetic plastics material foam.
  • an extension ladder which comprises two components, each component comprising two stiles and a multiplicity of rungs, each of which stiles comprises a hollow box section characterised in that the hollow section comprising two interlocked elongate sections of steel of a thickness in the range of from 0.5 to 0;8 mm coated with polyvinyl chloride, which elongate sections (2 and 3) are interlocked by having been slid one inside the other and the hollow being filled with polyurethane foam.
  • adder as used herein is a generic term that includes extension ladders, ladders, steps and the like.
  • the hollow section is formed from two separate sections which, when slid together, form the hollow section.
  • the two separate sections are made of steel generally having a wall thickness in the range of from 0.5 to 0.8 mm.
  • the formed hollow section will have good strength in pure bending about either the X ⁇ X or Y-Y axes, the strength naturally being dependent on the size of section, wall thickness of the material: and the material itself. However, such a hollow section will have little or no "torsional rigidity" because both sections are "open" sections.
  • each face of the section has been found possible to restrain each face of the section from moving relative to the other face by filling the section with a synthetic plastics material foam, especially a low density polyurethane foam. Whilst one could use a foam other than a low density foam, this is not advantageous from a cost or weight point of view.
  • the filling of the section serves not only the purpose of giving good torsional rigidity to the section but it also stiffens the thin walls of the section.
  • the sections of steel will be made of strip steel coated with P.V.C.
  • the steel will normally be treated against rusting prior to coating with P.V.C.
  • the forming of the hollow by using two sections is provided for two basic reasons, namely to allow the use of P.V.C. coated steel or similar material that cannot be welded into a hollow section and to allow the rungs of the ladder to be fitted with no external protrusions.
  • a ladder particularly applicable to extension ladders, with stiles made of foam filled steel is that, especially when a low density polyurethane foam is used, the ladder is considerably lighter than an equivalent wooden ladder, it is very little heavier than an equivalent aluminium ladder, it is very much cheaper, at least at the present time, than an equivalent aluminium ladder and the price is comparable, at least at the present time, with an equivalent wooden ladder.
  • the preferred low density polyurethane foam has a density of about 3 lb. per cubic foot.
  • FIG. 1 of the drawings shows stiles 1 made up of sections 2 and 3, connected by treads 4, with the stiles being filled with foam 5.
  • an aluminium section of ribbed tube 6, preferably of generally circular cross-section, has two ribs 7 formed thereabout, in the aluminium, spaced at the distance apart that the stiles are to be positioned, which strengthened tube is to form a rung or tread for the extension ladder.
  • Two inner hollow section members 2 with appropriately dimensioned holes therein have the ends of the requisite number of treads inserted therein and then an additional rib 8 is formed at each end of each tread, so that each tread is securely fastened to each inner hollow section member 2.
  • Caps (not shown) of steel for example are then generally fitted to the ends of the tube 6 to prevent ingress of foam thereinto in the later stages of manufacture (for economy of foam).
  • a second hollow seetion member 3 is then slid onto each :of the hollow section members 2 having treads 6 fastened thereto and the formed hollow section is then filled with low density polyurethane foam which is allowed to cure therein.
  • the end product is an extension ladder section.
  • the hollow section members 2 and 3 are advantageously made of P.V.C. coated steel.
  • the tube 6 forming the .tread can of course be any convenient shape, for example of "D" shape or be rectangular in cross section.
  • the present invention could be used in the manufacture of ladders other than extension ladders, if so desired.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Ladders (AREA)
EP78100247A 1977-07-06 1978-06-27 Improvements in or relating to ladders Expired EP0000344B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB2828377 1977-07-06
GB28283/77A GB1595202A (en) 1977-07-06 1977-07-06 Ladders

Publications (2)

Publication Number Publication Date
EP0000344A1 EP0000344A1 (en) 1979-01-24
EP0000344B1 true EP0000344B1 (en) 1981-04-15

Family

ID=10273200

Family Applications (1)

Application Number Title Priority Date Filing Date
EP78100247A Expired EP0000344B1 (en) 1977-07-06 1978-06-27 Improvements in or relating to ladders

Country Status (14)

Country Link
EP (1) EP0000344B1 (it)
JP (1) JPS5418362A (it)
AR (1) AR219759A1 (it)
AU (1) AU3774078A (it)
BR (1) BR7804218A (it)
CA (1) CA1094028A (it)
DE (1) DE2860615D1 (it)
DK (1) DK305678A (it)
ES (1) ES471508A1 (it)
FI (1) FI782172A (it)
GB (1) GB1595202A (it)
IT (2) IT7853480V0 (it)
NO (1) NO782223L (it)
ZA (1) ZA783722B (it)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2463298A1 (en) 2004-09-22 2012-06-13 ArborGen Inc. Reproductive ablation constructs

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR3024489B1 (fr) * 2014-07-29 2018-08-10 Gimaex International Echelle telescopique comportant des troncons d'echelle de densites differentes

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2855134A (en) * 1956-10-04 1958-10-07 Bauer Mfg Company Metal ladder
GB923788A (en) * 1960-10-18 1963-04-18 C F Taylor Plastics Ltd Improvements in or relating to joining a main tube to a secondary tube laterally fitted thereto
BE760720A (fr) * 1970-12-22 1971-05-27 Loix Gilbert Escalier metallique prefabrique.

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2463298A1 (en) 2004-09-22 2012-06-13 ArborGen Inc. Reproductive ablation constructs

Also Published As

Publication number Publication date
FI782172A (fi) 1979-01-07
IT7868578A0 (it) 1978-07-05
IT1172892B (it) 1987-06-18
ES471508A1 (es) 1979-02-01
NO782223L (no) 1979-01-09
JPS5418362A (en) 1979-02-10
DK305678A (da) 1979-01-07
IT7853480V0 (it) 1978-07-05
DE2860615D1 (en) 1981-05-07
BR7804218A (pt) 1979-04-17
CA1094028A (en) 1981-01-20
AR219759A1 (es) 1980-09-15
ZA783722B (en) 1979-06-27
GB1595202A (en) 1981-08-12
EP0000344A1 (en) 1979-01-24
AU3774078A (en) 1980-01-10

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