US3033310A - Foldable escape ladders with adjustable rungs - Google Patents

Description

K. c. MCLEOD 3,033,310

EOLDABLE EscAPE LADDERs WITH ADJUSTABLE RUNGs May 8, 1962 Filed Feb. 27, 1961 Kenyon C. M QL eod ATTORNEY United. StateSIP-atent l3,033,310 FOLDABLE ESCAPE LADDERS WIT ADJUSTABLE RUNGS v Kenyon C. McLeod, 167 Madison Ave., Toronto,

l -Y Ontario,-Canada Filed Feb. 27, 1961, Ser. No..91,944 4 Claims. (Cl. 182-196) This invention relates to an improved foldable ladder, especially usable as a fire escape, and which is extremely strong in construction, easily handled by the average person and which may be readily stored.

A primary object of the invention is to provide a novel ladder of the character mentioned and which includes novel means for the attachment and adjustment of the ladder rungs.

Other objects and the nature and advantages of the instant invention will be apparent from the following description of an exemplary embodiment taken in conjunction with the accompanying drawings wherein:

In the drawings:

FIG. l is a fragmentary perspective view of a ladder incorporating the invention;

FIG. 2 is an enlarged side elevation of one of the novel rungs, looking from left to right as indicated by line 2-2 of FIG. l;

FIG. 3 is a vertical section taken on line 3--3 of FIG. 2;

FIG. 4 is an enlarged fragmentary plan view taken substantially on line 4-4 of FIG. 1;

FIG. 5 is a horizontal section taken substantially on the plane of line 5-5 of FIG. 3;

FIG. 6 is an enlarged perspective view of a clamping element used in the invention; and

FIG. 7 is an enlarged, exploded perspective view of one end of a ladder rung of the invention prior to insertion of an adapter block inserted therein.

Referring to the drawing in detail a foldable or rope type ladder is indicated generally at 10 and includes exible side rails 12 of rope, cable, nylon cord, articulated links, etc., to which are adjustably secured rung assemblies indicated generally at 14.

The rung assemblies 14 include tubular rung members 16 of any suitable material, steel, aluminum, plastics, etc., which in the exemplary embodiment comprise a rectangular cross section to accordingly provide a flat foot-receiving surface 18 to which is secured or integrally formed therewith a friction increasing surface such as a resilient pad 20, knurling, etc.

Mounted in the open opposite ends 22 of the rung members 16 are adjustable clamp assemblies indicated generally at 24 and which cooperate with upper and lower, aligned transverse apertures 26 and 28 formed adjacent the terminal ends of the rung members 16.

The clamp assemblies 24 include a mounting block 30 conforming to the opening 22 of the rung members 16 and received longitudinally therein. The block 30 is illustrated as having a rectangular cross section and having extending transversely through the upper and lower surfaces an enlarged rectangular bore 32 which is alignable with and of a greater cross sectional area than the aligned apertures 26, 28. The end wall 34 of the block 30 includes a transverse, internally threaded bore 36 which communicates with the bore 34 and adjustably retains therein a lock or clamp screw 38. The screw 38 will include a suitably formed head for receiving a torque applying tool such as an Allen wrench, screw driver, etc., and in the instant case comprises a screw driver slot 40.

Received transversely through in diametrically opposed sides of the apertures 26, 28 are U-shaped clamp elements 42, 44 each of which being identical and interchangeable. The clamp elements 42, 44 each comprise 3,033,310 Patented May' 8, f 1962 a vertical pressure-applying portion 46 which is slightly concave-convex to conform to the outer surface of the flexible side rail with which it will engage. To aid in securing the rung members in a iixed position, the pressure-applying portions include transverse-.ribs on teeth 48. i; The ends of the portion 46 4terminate in upper and lower lips 50 and 52, respectively, which respectively overlie the upper and lower surfaces of the rung member in which they are mounted. It will be noted that the portion 446 of the clamp element 44 is engaged by the clamp screw 38 as indicated at 54; see FIGS. 3 and 5.

The rung assemblies are assembled as follows:

The block 30 is inserted into the open end 22 of the rung member 16 and the screw 38 is backed off so it does not protrude through the aperture 32. The clamp elements 42, 44 are inserted through the aligned apertures 22, 34, 28 in opposed relationship. The ilexible side rail 12 is then threaded between the elements 42, 44 and the rung members 16 are adjusted to a predetermined position along the side rail. The screw 38 is then rotated into engagement with the clamp element 44; see FIGS. 3 and 5, and the teeth 48 aid to retain the adjusted position of the rung members. The screw 38 can be readily backed olf for subsequent re-adjustrnent.

Thus it will be observed that the novel flexible ladder is readily assembled and includes parts which are readily constructed and maintained. The rungs will be retained in their adjusted position. The flat upper surface 18 and frictions surface give a user a feeling of security. The tubular rung members are especially strong and economical in manufacture and the assemblies 24 are readily accessible from the open ends 22 of the rung members.

The invention shown embodies the invention in a preferred form, however, it is intended that the disclosure be illustrative rather than definitive, and the scope of the invention is to be determined only as defined by the appended claims.

What is claimed as new is as follows:

1. In a ladder, an elongated side-rail, and a rung assembly securedon said side-rail and projecting laterally therefrom, said rung assembly comprising a rung member having an open ended, longitudinal bore and transverse aperture means therethrough and through which said side-rail extends, and side-rail clamp means accessible at the open end of said longitudinal bore of said rung member and projectionable into intersecting relationship with said transverse aperture means and adjustably and lockingly engaging a portion of said side-rail disposed in said transverse aperture means, a clamp block conforming to the interior cross-section of the longitudinal bore of said rung member and disposed in the open end of said rung member and including atransverse bore in alignment with said transverse aperture means and through which said side-rail extends, and a clamp screw mounted on said clamp block and intersecting the transverse bore for engaging the side rail and maintaining it fixed with respect to said clamp block, said rung assembly including opposed clamp elements disposed in said aligned aperture means and said bore at opposite sides of said side rail, said clamp screw engaging one of said clamp elements and retaining the side rail between said clamp elements.

2. In a ladder as set forth in claim 1 wherein said side rail comprises an elongated, ilexible, cord-like element, said clamp elements including upper and lower lip portions overlying opposed upper and lower surfaces of said rung member, said clamp elements including opposed clamp portions conforming to opposite side portions of said side rail.

3. In a ladder as set forth in claim 2 wherein said opposed clamp portions include friction increasing portions, said side rail having a cross-section other than polygonal.

o 4. In a ladder as set forth in claim 3 wherein said rung member is hollow and has a rectangular crosssection providing means for stabilizing said clamp block, said rung member including a at upper surface for providing a step upon which a users foot is readily received. 5

References Cited in the file of this patent UNITED STATES PATENTS 249,846 Macdonald Nov, 22, 1881 10 Rivers Nov. 25, 1890 Crosby Jan. 1, 1895 Crosby Jan. 1, 1895 Buckley Sept. 21, 1897 Yoder Jan. 10, 1956 FOREIGN PATENTS Sweden Feb. 18, 1947 Great Britain Aug. 22, 1929 Great Britain July 16, 1958

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