US3741341A - Self cleaning safety step bar - Google Patents

Abstract

A safety step bar, e.g. for use in the manufacture of ladders, includes a first longitudinally extending strip and a second longitudinally extending strip which are disposed in parallel relationship and spaced by a plurality of transversely extending bars between the inner surfaces of the first and second strips. The upper edges of the longitudinally extending strips are formed to define prongs for providing a non-skid surface for the step bar. The bar of the invention is disclosed as being manufactured by extrusion or like processes to define a monolithic structure to improve the manufacturing economies.

Description

United States Patent [1 1 Bustin 1 June 26, 1973 [54] SELF CLEANING SAFETY STEP BAR [76] Inventor: Leopold Bustin, P. O. Box 589,

Dover, NJ. 07801 [22] Filed: July 1, 1971 [21] Appl. No.: 158,929

[52] US. Cl. 182/228 [51] Int. Cl. E066 7/08 [58] Field of Search 182/228 [56] References Cited UNITED STATES PATENTS 2,895,573 7/1959 Hill 52/666 2,011,730 8/1935 Richmond 52/666 OTHER PUBLICATIONS Busting" Aluminum and Stainless Steel Gratings, Page 4, Catalog No. Al-11, 11/14/66 Primary Examiner-Reina1do P. Machado Attorney-Popper, Bain, Bobis & Gilfillan [57] ABSTRACT A safety step bar, e.g. for use in the manufacture of ladders, includes a first longitudinally extending strip and a second longitudinally extending strip which are disposed in parallel relationship and spaced by a plurality of transversely extending bars between the inner surfaces of the first and second strips. The upper edges of the longitudinally extending strips are formed to define prongs for providing a non-skid surface for the step bar.

The bar of the invention is disclosed as being manufactured by extrusion or like processes to define a monolithic structure to improve the manufacturing economies.

1' Claim, 5 Drawing Figures PATENTEUJUNZB mm 3.741. 341

29 FIG. 4

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3/ ATTORNEYS SELF CLEANING SAFETY STEP BAR BACKGROUND OF THE DISCLOSURE This invention relates to the field of structural shapes. More specifically, this invention relates to structural bars useful for the manufacture of steps for ladder structures.

Self cleaning safety step bars are generally known in the ladder construction art. It is known in the ladder manufacturing arts to provide step bars which have an abrasive or other non-friction surface as well as a plurality of vertically extending openings which accommodate the disposition of dirt which may be deposited upon the step bars from the feet of users.

Typical of the step bars generally known in the arts is that which may comprise first and second longitudinally extending strips which are separated by a generally longitudinally extending sinuous strip. The upper surfaces of the respective strips are provided with a non-skid surface or upwardly extending prongs and the sinuous strip cooperates with the longitudinally extending strips to define the vertically extending openings through which dirt scraped from the shoes of a climber can pass to maintain the ladder in a relatively clean condition.

Although step bar structure of the type described above has been very well accepted in the industry, it has been recognized by those skilled in these arts as being relatively expensive to manufacture. Specifically, the structure of the average metal ladder utilized in the industry today includes a pair of parallel ladder rails between which extends a plurality of longitudinally spaced step bars or rungs. Where such step bars are of the self cleaning type, manufacturing difficulties have been experienced in two areas. Initially, the fabrication of the step bars has been a source of difficulty and secondly the securing of the step bars to the ladder rails has also caused problems.

Considering initially the fabrication problems which have been experienced, the prior art manufacture of self cleaning step bars has required the positioning of spaced longitudinally extending strips in special jigs. Thereafter, the strips are joined with spacer means by such procedures as welding, rivoting or the like. It is considered to be clear that avoiding the use of such special jigs and the accomplishing of plural securing steps would be definite improvements in the art of manufacturing safety step bars.

Considering secondly the problem relating to the securing of step bars to ladder rails, it will be understood by those skilled in this art that the manufacture of ladders using known step bars has required the fitting of the outer step strips as well as an individual fitting of the spacer section at each point of connection between the step bar and the ladder rails. Often such manufacturing steps require a plurality of cuts on each end of the step bar structure and once cut, the step bar must be secured to the ladder rails by welding three elements of the bar to the ladder rail, one of the welds being a difficult inner section weld.

SUMMARY OF THE INVENTION It is an object of the present invention, therefore, to provide a structural bar capable of use as a self cleaning step bar, which is inexpensive to manufacture and structurally sound.

A further object of the present invention is to provide a self cleaning safety step bar which is non-skid and l which provides no source for the deposit of dirt and other materials during use.

Still another object of the present invention is to provide a safety step bar configuration wherein manufacture of ladders therewith is rendered more easy and more economical.

These objects and others not enumerated are achieved by the self cleaning safety step bar according to the invention one embodiment of which may include first and second spaced elongated strips extending longitudinally, a plurality of longitudinally spaced transversely extending spacer bars disposed between said first and second strips, and a plurality of prongs formed on the surfaces of said first and second elongated strips to provide a source of friction.

BRIEF DESCRIPTION OF THE DRAWINGS A more complete understanding of the present invention may be had in the light of the following detailed description thereof, particularly when read in the light of the accompanying drawings wherein:

FIG. 1 is a plan view, partly in cross-section of a ladder structured in accordance with the prior art teaching's regarding typical self cleaning safety step bars;

FIG. 2 is a view similar to FIG. 1 but showing a ladder utilizing a self cleaning safety step bar according to the invention;

FIG. 3 is a perspective view of a self cleaning safety step bar according to the invention;

FIG. 4 is a plan view of a safety step bar according to the invention; and

FIG. 5 is a cross-sectional view through the plane 5-5 of FIG. 4.

DETAILED DESCRIPTION The problems to which the present invention are directed may be best understood by referring to FIG. 1 wherein a ladder utilizing self cleaning safety step bar structure is shown. Specifically, prior art ladder 10 is seen to comprise first and second ladder rails 11 and 12, respectively. Rails 11 and 12 extend longitudinally in parallel spaced relation and are separated by a plurality of step bars or rungs 14 in a conventional manner.

The prior art step bar 14 comprises first and second longitudinally extending strips 16 and 17 which are separated by a generally longitudinally extending sinuous spacer member 18. Each of the longitudinally extending strips and the spacer member are provided with perforations along their upper surfaces to provide a non-skid surface. Further, the vertically extending spaces defined by the cooperation of the longitudinally extending strips and the continuous member provides for the self cleaning aspect in that dirt scraped from the shoes of a climber will drop down between the strips and the spacer and not be built up on the surface of the ladder step bar so as to generate a possibility of slipperyness or other unsafe condition.

The structural difficulties attendant to ladders structured in accordance with the prior art as disclosed in FIG. 1 are reasonably evident. Specifically, the manufacture of the self cleaning safety step requires that the continuous spacer bar be joined to the longitudinally extending strips at a plurality of points 19 along the length of the bar structure. This of course, requires a must be cut and then the continuous strip must be cut such as to define a three point surface which fits the circular cross section of they ladder rail. This of course,

requires a special cutting in each individual case and renders manufacture of a ladder in this rnannervery difficult. Further, once the step bar is cut, securing of the step bar to the ladder railrequires welding at three points. All of this is expensive and disadvantageous. 1

The self cleaning step bar according to the present invention is advantageousvbecause of the ease of its own manufacture, however it is also advantageousbe cause of the manner in which it facilitates the manufacture of ladder structure and avoids the prior art difficulence numeral 20. Ladder 20 is seen to compri se'first and second ladder rails22 and 24 each of which being generally cylindrical in cross sectional configuration.

Rails 22 and 24 extend longitudinally in parallel spaced relation and are separated by a plurality of safety step bars according to the presentinvention, which barsilare designated generally by the reference numeral, 26$. i

Safety step bar 26 is a generally U-shapedrnembergl having a first" longitudinally extendingstrip 28 and a second longitudinally extending strip 29 disposed par allel to the first stripQ Each longitudinallytextending f strip includes an upper surface, a lower surface, an inner surface and an outer surface, the outer surface of each having a shoulder formed thereon to define a longrtudmally extending portion of increased thickness ad- 9 tolform p gs 33, bar 26 is passed through a stamping machine wherein the base portion of U I shapedbar26 is stamped to define openings 37 thereby forming transversely extending spacer bars 31. Such jacent the upper surface. The first and second longitudinally extending strips arespaced by a plurality of transversely spaced bars 31 extending between the inner surfaces of firstand second strips 28 and 29,- the also discussed below in detail, a pluralityof upwardly for step bar 20. i

As is evident from FIG; *2, stepbar 26 is joined 0' first and second ladder rails 22 and24 by welds 35. In this.

regard, it is to benoted that because ofthe' absence of a generally longitudinally extending" spacer member such as that 18 of the prior art embodiment of FIG. 1,

there is no need for special cutting orshaping of a spacer element between a longitudinally extending strips 28 and 29. Thus, in manufacturing a ladder 20,

it is satisfactory to out along strip of safety step bar into detailed structure of which is discussed below. As is sections to form a plurality of safety step bar rungs 26 position first and second ladder rails 22and 24 in parallel spaced relationship position the rungs26appropriately along the length of the ladder between first and second ladder rails 22 and 24 and thereafter join the ladder rails and step bars such as by welding 35. Thus, in manufacturing a ladder such as ladder 20, there is no need for custom fitting of the step bars to the ladder rails, rather the step bars can merely be cut, positioned against the rails and appropriately weldedi Considering now the detailed construction of step bars according to the invention and with particular refproced rehet ing relieved erencefto FIGSLY3, d andfls stepfbar20ca be seenytoj g befal generallyxu shapcd strueturecomprising first lonj gitudinallyextendihg any" 28; second longitudinally extending strip. 29 andla plurality of transversely extendinglspacer bars 31. In the embodiment shown, the 1 upper edges of first and second longitudinally extend ing strips 28 and 29 are increased in thickness such as to form shoulders on the outer surfaces of each strip. 1 These thickenedsections'are provided to accommo date, thejforrning of a plurality of frictiongenerating prongs 33 on the upper edges of strips 28 and 29 in a manner discussed below in detail.

As may be best seen in 4, spaced transverse bars v i 31 cooperate to define openings 37 between first and I secondlongitudinally extending strips 28 and 29. These openings are to accommodate the passage ,there-. through of dirt andlike materials which may be scraped M from the feet of a user of a ladder structured in accor.-

dance with the invention.

, Considering now the manufacture of a safety step bar according to. the invention, the preferredmethod of l manufacture is to extrude ajgenerally U-shaped bar having a crosssectionalconfiguration asshown in FIG. 5. Suchane'xtrusion canbelmade by any of the meth ods ofextrusion for accomplishing the manufacture of sucha productfas isgenerally known by those skilled g in the extrusion ens; With the basic extrusion shape I fornied,prongs33 are formedbypunching. More specifically,l the upper edges of longitudinally, extending strips 28 and 29 arepassed through a punchingappara tus which punchesjthe upper edges to formielieved wardly from the surface of strips 28 and 29.

After the relieved portions 38 are formed in strips 28 stamping is the final manufacturing operation other than suitablefinishing procedures as may be" generally j"knownto those skilled in these arts. 1

- it is evident, therefore, thatthe manufacture of a step gbar according to the present invention is a three-step 3 rtionsin the upper edge of the longitudh 1 R nally extending strips to, form prongsl and, finally, .1. l

punchingjthe base ofthe'u shaped structure to provide the openings 37 which permit the self cleaning function of the baras well as to form transversely extending spacer barsfil. f r I. I

.ltwill be evident to those skilled in these arts that the structure of step bar. according to the"invention is unique because. itcomprises a monolithic structure requiring no intennediatesecuring, e. g. between the 1on gitudinally extending stripsand the transverse spacer bars, it requires. no customized cutting to adapt it for use with particular ladder rails, and it is a structurally sound elementcapable of use in virtually every step bar application. 7

Although only a single preferred embodiment of step bar according to the invention is disclosed in detail, it is considered to be manifest that many modifications and'variations to the basic teachings can be made without departing from the spirit thereof.

I claim: g

l. A one piece safety step bar comprising a first longitudinally extending strip having an upper surface, a lower surface, a flat inner surface and an outer surface, said outer surface of said first longitudinally extending strip having a longitudinally extending portion of increased thickness adjacent its upper surface;

a second longitudinally extending strip having an upper surface, a lower surface, a flat inner surface spaced from but disposed directly opposite said flat inner surface of said first longitudinally extending strip, and an outer surface, said outer surface of said second longitudinally extending strip having a longitudinally extending portion of increased thicklongitudinally from each adjacent relieved portion.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3,741,341 Dated June 26. 1973 Inventor(s) Leopold stin It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the claims, column 6, line 10, after "being" insert spaced-.

I Signed and sealed this 27th day of Novemlier 1973.

(SEAL) Attest:

ED AR MTLET HER R. RENE D, TEGTMEYER Attestlng Offlcer Acting Commissioner of Patents FORM PO-1050 (10-69) USCOMM-DC 6O376-P69 u.s. eovsaunsn-r PRINTING OFFICE Isis o-ass-su.

Claims (1)

1. A one piece safety step bar comprising a first longitudinally extending strip having an upper surface, a lower surface, a flat inner surface and an outer surface, said outer surface of said first longitudinally extending strip having a longitudinally extending portion of increased thickness adjacent its upper surface; a second longitudinally extending strip having an upper surface, a lower surface, a flat inner surface spaced from but disposed directly opposite said flat inner surface of said first longitudinally extending strip, and an outer surface, said outer surface of said second longitudinally extending strip having a longitudinally extending portion of increased thickness adjacent its upper surface; a plurality of transversely extending spaced bars between said inner surfaces of said first and second longitudinally extending strips, said spaced bars being longitudinally displaced and disposed adjacent said lower surfaces of said first and second longitudinally extending strips; and a plurality of relieved portions formed in said upper surfaces of said first and second longitudinally extending strips, each said relieved portions being longitudinally from each adjacent relieved portion.

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