US3638759A - Metal ladders - Google Patents

Metal ladders Download PDF

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Publication number
US3638759A
US3638759A US23738A US3638759DA US3638759A US 3638759 A US3638759 A US 3638759A US 23738 A US23738 A US 23738A US 3638759D A US3638759D A US 3638759DA US 3638759 A US3638759 A US 3638759A
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US
United States
Prior art keywords
ribs
rung
pair
stiles
tabs
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 - Lifetime
Application number
US23738A
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English (en)
Inventor
Robert Anton Englhardt
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.)
Indal Canada Ltd
Original Assignee
Indal Canada 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 Indal Canada Ltd filed Critical Indal Canada Ltd
Application granted granted Critical
Publication of US3638759A publication Critical patent/US3638759A/en
Anticipated expiration legal-status Critical
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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
    • E06C7/084—Rungs comprising projecting tabs or flanges
    • 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

Definitions

  • each stile has a pair of spaced pa -a]- lel ribs on its inner and outer faces, and is formed with pairs of [52] [1.5. Ci ..182/194, 182/228 Slots close to the ribs, and each rung has a cross Section in the [51] 10 Cl. "E066 7/50 form of a hollow parallelogramy with two spaced parallel tabs Fleld 0f p j g at each end.
  • SHEET 2 OF 2 ATTORNEYS METAL LADDERS This invention relates to metal ladders and is particularly though not exclusively applicable to ladders in which the stiles and rungs are formed from light alloy extrusions.
  • the invention consists in a metal ladder including a pair of stiles and interconnecting rungs, in which each stile has a pair of spaced parallel ribs on the side thereof facing towards the other stile, and the rungs are of noncircular cross section with substantially flat opposed surfaces lying generally parallel with and in contact with, or closely adjacent to the respective ribs on the stiles.
  • each rung is of hollow box section, having two further parallel generally flat upper and lower surfaces, and in a particular preferred construction the cross section of each rung is a parallelogram, with the top and bottom surfaces inclined to the side surfaces.
  • the ribs of the stiles are preferably spaced inwardly from the edges thereof.
  • the invention consists in a metal ladder including a pair of stiles, and interconnecting rungs, in which each stile has a pair of spaced ribs on its outer surface, and is formed with an elongated aperture adjacent each rib at the position of each rung, and each rung has a pair of tabs at each end which extend through the respective apertures and are bent back over the adjacent rib.
  • each rung is of hollow box section, with substantially flat opposed side surfaces, and the tabs are extensions of said side surfaces.
  • each stile has a pair of spaced parallel ribs on both its inner and outer surfaces, preferably aligied with each other, and each rung has flat opposite side surfaces which abut against the inwardly facing ribs, and tabs which pass through apertures in the stiles and are bent over the outwardly facing ribs.
  • FIG. I is an end view of an extruded metal stile for a ladder according to the invention.
  • FIG. 2 is an inner side view of part of the stile of FIG. 1, showing in cross section a metal rung attached to the stile,
  • FIG. 3 is a sectional view through the stile on the line III-III in FIG. 2, showing the method of securing the end of a metal rung,
  • FIG. 4 is an outer side view of part of the stile showing the external view of the connection between the stile and the rung,
  • FIG. 5 is a perspective view of one end of a metal rung showing the preformed tabs used in making the connection
  • FIG. 6 is a general front elevation on a small scale ofa metal ladder according to the invention having rungs and stiles connected together in the manner illustrated.
  • the ladder comprises a pair of elongated stiles I0, each formed as an aluminum alloy extrusion, and a series of interconnecting rungs I2 each of which is also a hollow box-section aluminum alloy extrusion.
  • Each stile comprises a generally flat web portion 13 (see FIG. 1), approximately 2% inches in width, with a relatively narrow perpendicular flange 14 at each edge.
  • a pair of shallow spaced ribs 15 is provided on the inner face of the main web, and a further pair of spaced ribs 16 on the outer face, these ribs l5, 16 being aligned one with another and spaced apart across the web at an interval of approximately 1% inch.
  • each slot has a length (parallel to the length of the stile) of approximately 1 inch and being positioned in the part of the web between the ribs 15, 16, and closely adjacent to and parallel with the ribs. For a reason which will become apparent the slot adjacent one edge of the web at each rung position is slightly above the level of the slot adjacent the other edge of the web.
  • Each rung 12 is of hollow box section, the actual section being a parallelogram (see FIG. 2) with a relative inclination of approximately 75 between the side, or vertical" surfaces 20, and the top and bottom surfaces 21, 22.
  • the top surface 21 may be fluted or ribbed to provide an antislip tread.
  • the perpendicular distance between the opposite side surfaces 20 is approximately 1% inch, i.e., slightly less than the interval between the pairs of ribs 15 on the inner surface of the stile.
  • each rung is first cut to a length slightly greater than the required perpendicular distance between the stiles l0 and each end of a rung is then trimmed by cutting out a short section of the upper and lower surfaces 21, 22, (see FIG.
  • the ribs 15 on the adjacent or inwardly facing surfaces of the stile webs are omitted and the engagement between the tabs 24, 2S, and ribs 16 on the outer surfaces are relied upon to form the joint.
  • the ribs 16 on the outer surfaces of the stiles are omitted and the tabs 24, 25 on the rungs are simply curled or crimped over against the outer surface of the web 13, the rigidity of the joint being provided by the engagement of the rung surfaces 20 with the inwardly facing ribs 15 and the positioning of the tabs 24, 25 within the elongated slots 17 in the web.
  • the ribs 15, I6, are formed on both the inner and outer surfaces of each stile, as described above.
  • a metal ladder including a pair of stiles, and interconnecting rungs, in which each stile has a pair of spaced ribs on its outer surface, and is formed with an elongated aperture adjacent each rib at the position of each rung, and each rung has a pair of tabs at each end which extend through the respective apertures and are bent back over the adjacent rib.
  • each rung is of hollow box section with substantially flat opposed side surfaces, and the tabs are extensions of two of said side surfaces.
  • a metal ladder having a pair of stiles and interconnecting rungs, each stile has a pair of spaced parallel ribs on both its inner and outer surfaces, preferably aligned with each other, and each rung has flat opposite side surfaces which abut against the inwardly facing ribs, and tabs which pass through apertures in the stiles and are bent over the outwardly facing ribs. 5

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Ladders (AREA)
US23738A 1970-01-16 1970-03-30 Metal ladders Expired - Lifetime US3638759A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB2138/70A GB1283934A (en) 1970-01-16 1970-01-16 Improvements relating to metal ladders

Publications (1)

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US3638759A true US3638759A (en) 1972-02-01

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US23738A Expired - Lifetime US3638759A (en) 1970-01-16 1970-03-30 Metal ladders

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US (1) US3638759A (de)
DE (1) DE2029743A1 (de)
GB (1) GB1283934A (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3970400A (en) * 1973-07-09 1976-07-20 Robert John Reid Deformingly interlocked structural joint
US4655320A (en) * 1984-12-14 1987-04-07 Benboid Pty Ltd. Ladder means and method of production
US5180031A (en) * 1990-12-11 1993-01-19 Smith Daniel S Gardener's aid for sloped ground
US6899213B1 (en) * 2000-10-20 2005-05-31 Lankfer Diversified Industries, Inc. Brake-transmission interlock device

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2535533C2 (de) 1975-08-08 1983-10-06 Koweko AG, St.Gallen Durch Strangpressen hergestellter Längsholm aus Leichtmetall für Leitern
DE2910618C2 (de) * 1979-03-17 1981-06-19 Hailo-Werk Rudolf Loh Gmbh & Co Kg, 6342 Haiger Leiter mit Stufen und zwei Längsholmen
DE2910617C2 (de) * 1979-03-17 1981-07-16 Hailo-Werk Rudolf Loh Gmbh & Co Kg, 6342 Haiger Leiter mit Stufen und zwei Längsholmen
DE3065120D1 (en) * 1979-04-05 1983-11-10 William Bailey Method of and apparatus for forming a joint between a step and a stile of a ladder

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US944000A (en) * 1908-08-01 1909-12-21 Heinrich Schoenich Ladder.
GB497082A (en) * 1936-03-13 1938-12-05 Heinrich Wuester Jun Improved process of manufacturing step-ladders and so forth
US2957543A (en) * 1956-05-23 1960-10-25 White Metal Rolling & Stamping Extension ladders
US3279051A (en) * 1965-04-05 1966-10-18 Minshall Aubrey Wilson Method of forming a joint between a metal rail and a hollow metal rung

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US944000A (en) * 1908-08-01 1909-12-21 Heinrich Schoenich Ladder.
GB497082A (en) * 1936-03-13 1938-12-05 Heinrich Wuester Jun Improved process of manufacturing step-ladders and so forth
US2957543A (en) * 1956-05-23 1960-10-25 White Metal Rolling & Stamping Extension ladders
US3279051A (en) * 1965-04-05 1966-10-18 Minshall Aubrey Wilson Method of forming a joint between a metal rail and a hollow metal rung

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3970400A (en) * 1973-07-09 1976-07-20 Robert John Reid Deformingly interlocked structural joint
US4655320A (en) * 1984-12-14 1987-04-07 Benboid Pty Ltd. Ladder means and method of production
US5180031A (en) * 1990-12-11 1993-01-19 Smith Daniel S Gardener's aid for sloped ground
US6899213B1 (en) * 2000-10-20 2005-05-31 Lankfer Diversified Industries, Inc. Brake-transmission interlock device

Also Published As

Publication number Publication date
GB1283934A (en) 1972-08-02
DE2029743A1 (de) 1971-07-29

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