US3757896A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ladders
Assignee: WALTHAMS Ltd
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Filing: 1972-01-26
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Granted: 1973-09-11
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Expires: 1992-01-26
Abstract
Abstract This invention relates to a ladder capable of being erected from a plurality of similar rungs and links, the ladder being capable of being folded in a zig-zag manner and also of being dismantled into a kit of component parts. The ladder comprises a plurality of rungs and side links which in the extended form of the ladder are adapted to maintain the spacing of the rungs and means between the rungs and the side links for inter-engagement.
Inventors
- 👤 W Lee
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 11:40
CPC Classifications
B; B63; B63B; B63B29/00; B63B29/20; B63B29/205; E; E06; E06C; E06C1/00; E06C1/52; E06C1/56
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
100 words
A ladder comprising a plurality of rungs and a plurality of side links, said rungs and said side links being constructed of a plastic material, each of said rungs having an engaging portion integrally formed at each end thereof to interconnect at least two consecutive side links, and each of said side links defining spaced retaining means at each end for snap engagement with the engaging portion of one of Said rungs whereby said rungs and said side links are selectively interengagable to form a ladder in which the rungs are maintained in parallel spaced relationship by said side links.
Claim 2
Dependent Claim
100 words
A ladder comprising a plurality of rungs and a plurality of side links, said rungs and said side links being constructed of a plastic material, each of said rungs having an engaging portion integrally formed at each end thereof to interconnect at least two consecutive side links, and each of said side links defining spaced retaining means at each end for snap engagement with the engaging portion of one of Said rungs whereby said rungs and said side links are selectively interengagable to form a ladder in which the rungs are maintained in parallel spaced relationship by said side links.
Claim 3
Dependent Claim
42 words
A ladder as claimed in claim 1 characterised in that the engaging portion on each rung is rotatably interconnected with at least one of said links associated therewith, whereby the ladder can be collapsed from an extended configuration to a folded configuration.
Claim 4
Dependent Claim
26 words
A ladder as claimed in claim 1 characterised in that the engaging portion is a peripheral groove provided at or towards an end of said rung.
Claim 5
Dependent Claim
46 words
A ladder as claimed in claim 3 characterised in that said groove has a radial projection over at least part of its width, said projection being adapted to engage said retaining means on said side link, to restrain relative rotation between the rung and said link.
Claim 6
Dependent Claim
79 words
A ladder as claimed in claim 1 characterised in that the retaining means comprises an elongate slot adapted to accommodate said engaging means, said slot including a constriction, dividing said slot into first and second portions whereby on entering said engaging means into said first portion pressure can be applied to said rung to snap said engaging means passed said constriction and into said second portion, whereupon said engaging means is retained in said second portion of the slot.
Claim 7
Dependent Claim
48 words
A ladder as claimed in claim 1 characterised by the inclusion of one or more spacing elements adapted to project laterally of the links of said ladder in the extended state to space said links and rungs for the surface against which the ladder is to be used.
Claim 8
Dependent Claim
32 words
A ladder as claimed in claim 6 characterised in that the spacing element has a pair of arms each of which is bifurcated at its end, and adapted to embrace a rung.
Claim 9
Dependent Claim
64 words
Apparatus as claimed in claim 7, characterised in that each bifurcation has at its outer extremity a laterally extending finger adapted to engage the edge of a contiguous link, whereby said ladder and elements can be collapsed on an extended configuration and wherein each link is rotatable about the engaging means relative to said element to subtend an angle of not more than 90*
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-09-10 | 1977-03-12 | 1977-09-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-10 | 1981-03-12 | 1981-09-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-10 | 1985-03-12 | 1985-09-11 | $7700.00 | Window Closed / Lapsed |