US2632592A - Ladder - Google Patents

Description

March 24, 1953 H. M. EISMANI 2,632,592

LADDER Filed Oct. 14, 1949 IN VHV TOR.

HAkRY 44. EISMAN Patented Mar. 24, 1953 LADDER Application October 14, 1949, Serial No. 121,318

1 Claim.

This invention relates to ladders, and more particularly to a ladder head of inverted V-shape, whichlis adapted to be assembled with a pair of straight ladders o-r ladder sections so as to form a self-supporting ladder or a trestle for use in scaffolding.

@One objectof this invention is to provide a ,device of the above naturehaving a pair of hinged head sections which have means for positively and securely connecting a pair of ladder sections thereto. Q

Another object is toprovide an improved allmetal ladder construction wherein the rungs and the side rails are joined by connections which provide strength and rigidity in the ladder, and

avoid the use of welding.

.A furtherobject is to provide a ladder head of *theabove nature which will be simplein construction, inexpensive, to manufacture, easy to :assemble. and manipulate, compact, ornamental in appearance, and very efficient and durable in use.

With these and other objects in view, there has "been illustrated on the accompanying drawing one-lform in which the invention may con-' tions would be assembled with a ladder section.

Referring now to the drawing, in which like reference numerals denote corresponding parts throughout the several views, the numeral B indicates the improved ladder head which comprises a pair of head sections l2, having pairs of upstanding side rails l3, l4, and 5, I6, respectively, joined by pairs of horizontal tubular rungs |1, l8, and I9, 23.

Eachof the side rails l3, 4, IE, I6 is approximately C-shaped in cross section, as illustrated in Fig. 2 for example, and comprises a flat longitudinal web 2| and a pair of inturned flanges 22, 23 which are outwardly oifset from said web and parallel thereto-said side rails preferably being constructed from aluminum and formed by an extrusion process.

The head sections l2, are so assembled that the webs2| of the respective pairs of side rails face each other, and are swingably connected webs and provided with pivots 23.

were STATES PATENT oFFice i.

angular-hinge brackets 24, secured to said The construction whereby the ends of the rungs H, l8, I9, and 20 are connected to the side rails l3, l4, l5, I6 is exemplified in Fig. 2 with reference to the rail 13 and the rung I8. The Web 2! is provided with a circularcentral aperture 21 which has a diameter intermediate the inner and outer diameters of, thetubular'rung l8, and which has a pair of opposite outstanding notches 23, 28 formed on a .diameterwhichis substantially equal to the outer diameter of said rung l3. w

The end surface of therung I3 is so cut as to provide a pair of arcuate projections 29,, 29 which are adapted to be received in thenotches 28, 23. Further, the end portion of the mpg, 8 is provided with inner screw threads 30, which are adapted to receive a screw plug 3| having-a head 32. Thus, it will be seen that. the end'of the rung I8 may be applied in abutting relationship to the web' 2| concentric to 'the aperture, 21,-and with the projections 29 disposed in the notches 28.

The depth of the projections 29 is made equal to orslightly less thanthe thickness of, the web 2|, so that the screw plug 3| may be entered through the aperture 21 and engaged with the threads 30 for clamping the web 2| tightly between the head 32 of the plug 3| and the end of the rung |8, thus providing a strong and rigid connection between the side rail |3 and said rung.

The lower pair of rungs il, l 9 are connected to the side rails I3, I 4, l 5, I6 by a construction which is identical to that described above, excepting only that the screw plugs 3| are slightly modified to provide elongated heads 33 which project outwardly of the inturned flanges 22, 23. 1

The elongated heads 33 are for the purpose of entering notches 34 in the upper ends of side rails 35, 36 of a ladder or ladder section 31. The lower ends of the side rails l3, I4 of the head section II are provided with a pair of notches 38 which are so disposed as to firmly engage a top rung 39 of the ladder section 31 when the elongated plug heads 33 are engaged in the notches 34.

In order to prevent accidental separation of the head section II from the ladder section 31, the lower portions of the side rails l3, H! are provided with a pair of notched locking arms 40 which are swingably attached to the webs 2| by any suitable means, such as rivets 4 I. It will be seen that the locking arms 4!! are so disposed as to be swingable in an outward and downward direction for engagement with the top rung 39 of the ladder section 31 for holding the respective ladder sections securely in assembled relationship. The head section [2 also is provided with a pair of lower end notches 42, 42, and a pair of locking arms 43, 43 for attaching a ladder section thereto.

As a provision for holding the head sections ll, [2 in a predetermined angular relationship duringuse, pairs of pivoted links, 45 are swingably attached to respective end portions of the rungs I8, 20. The pairs of links 44, 45, may, of course, be folded so as to permit the head sections II, l2 to be swung together and thus occupy a relatively small space for transportation or storage.

Operation In operation, the ladder head twill-be found to have a very strong and rigid construction which wil1 not only be capable of carryinghea-vy loads, but will also be light in weight, The ladder head may beusedeither alone, or when assembled with a pair of ladder sections .31, as a self-supporting ladder which willrequireano aux- -;il iary'bracing or other support.

The height of the ladder head In may be increased as desired, merely'by connecting a pair hold the respective ladder sections firmly against separation.

A ladder section may, of .course, be attached to the "head section 12 in the same manner.

While there has been disclosed in this specification one form in which the invention maybe embodied, it is to be understood that item is shown fonthepurpose-of illustration only, and

that the invention is not to be limited to the specific disclosure, but may be modified and embodied in various other forms without departing from its spirit. In short, the invention includes all the modifications and embodiments coming within the scope of the following claim.

Having thus fully described the invention, what is'zclaimed as new, and for which :it is desired to secure Letters Patent, is:

In a ladder, the combination comprising a pair of parallel channel-shaped side rails located with their webs on the inside, a plurality of tubular cylindrical rungs internally threaded at their opposite ends extending between and abutting the webs of said side rails, the opposite ends of said rungs each having a pair of diametrically opposed rectangular prongs interlockingly fitted into acorresponding pair of preformed diametrically opposed rectangular notches formed in aligned circular apertures in said webs, and a plurality of headedscrew plugs entered through the outside of said apertures and having exterior threaded portions engaging the internally threaded ends of said rungs, said notches being covered by-the'heads of said screw plugs, whereby said rungs will be firmly held in said Webs by said plugs and relative rotation between said rungs and said rails will positively be prevented.

HARRY M. 'EISMAN.

REFERENCES CITED 'The following references are of record in the .file of this patent:

UNITED STATES PATENTS Number Name Date 376,794 Barns :Jan. 24, 1888 1,036,932 Thompson Aug. 27, 1912 1,935,349 =Breslow Nov. 14, 1933 2,113,403 Harmon Apr. 5, 1938 2,594,561 Huck Apr.:29, 1952 FQREIGN PA NT Number .Country Date 0,41 Great .Britai-n May 1903

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