US3165169A - Ladder holder - Google Patents

Description

J. F. MACHEN LADDER HOLDER Jan. 12, 1965 2 Sheets-Sheet 1 Filed Sept. 15, 1965 INVENTOR:

3,165,169 LADDER HOLDER James F. Machen, 2495 Robinwood Ave, Toledo, Ohio Filed Sept. 13, 1963, Ser. No. 308,766 1 Claim. (Cl. 182--170) This invention relates to ladders and more specifically to an adjustable attachment for rung and extension with the purpose of making them self-supporting.

There are many situations where it is necessary to reach or climb overhead, but where a step-ladder is too short and where at the same time an extension ladder cannot be leaned. Examples of such situations are: in reaching high ceilings; in working on suspended lighting fixtures; working against plate glass; working against aluminum siding; for tree surgery; etc.

Ordinarily, scaifolding or special lift devices are required for safely reaching overhead in such instances. This equipment is often expensive, cumbersome, and/or requires excessive time and labor to use.

Accordingly, it is an object of this invention to provide an attachment for ordinary rung or extension ladders that will make them self-supporting.

Another object of this invention is to provide such a self-supporting attachment that is safe and sturdy and that provides a maximum of support stability.

Another object of this invention is to provide an attachment that is portable, compact, light-weight, easyto-use, and easy-to-store.

Another object of this invention is to provide a single adjustable attachment that will accommodate a wide range of ladder sizes and a variety of set-up arrangements.

Another object of this invention is to provide an attachment which is low in cost, yet handy, rugged, and serviceable.

Another object of this invention is to provide a device which will greatly extend the usefulness of ordinary rung and extension ladders.

Other objects and advantages of this invention will be more apparent when the following description is taken together with the drawings, in which:

FIG. 1 is a rear elevation view of a two-section extension ladder supported by a preferred embodiment of this invention.

FIG. 2 is a side elevation view relating to FIG. 1.

FIG. 3 is an enlarged fragmentary view of a portion of FIG. 1 showing details of the rung attachment and leg connections.

FIG. 4 is an enlarged fragmentary view of another portion of FIG. 1, with downward perspective added, showing the chain arrangement at the bottom rung of the ladder.

FIG. 5 is an enlarged fragmentary view of a portion of one support leg broken away to show details of the adjustment stop.

FIG. 6 is a view as in FIG. 5, but taken at the foot of one support leg to show details of the chain connection.

FIG. 7 is an enlarged fragmentary cross-sectional view taken along line 7-7 in FIG. 3.

Referring to FIGS. 1 through 4, an extension rung ladder composed of lower section 10 and upper section 11 is supported by a preferred embodiment of this invention having legs 12 and 12' composed of upper tubular leg portions 13 and 13 which telescope for adjustment into lower tubular leg portions 14 and 14'. Legs 12 and 12 are hinged to a common rung clamp 15 which is attached in the center of a rung 16 of the extended upper ladder section 11. v

Legs 12 and 12 form a tripod configuration with the ladder. Safety chain 17 connects from rung clamp 15, ex-

;United States Patent 0 ice tends down the ladder, around bottom rung 18, out to snap fastener 19 at the foot of leg 12, across to snap fastener 19 at the foot of leg 12, and back to bottom rung 18 where it is secured by snap fastener 20. Safety chain 17 serves the dual function of preventing the legs or ladder from accidentally shifting position relative to each other thus maintaining stability, as well as preventing the upper ladder section 11 from being forced upward by legs 12 and 12' when all of the load is on the lower ladder section 10.

Referring to FIGS. 3 and 7, rung clamp 15 is secured to a rung 16 of the upper ladder section 11 by means of L-bolt 21 which is tightened by wing-nut 22. Rung clamp 15 is designed with a channel shape in cross-section to permit it to accommodate a variety of rung sizes and shapes. L-bolt 21 is bent with a slightly acute included angle to prevent accidental detachment of the clamp should wingnut 22 lose its tightness. Downward projection 23 on rung clamp 15 is provided to anchor safety chain 17 at its upper end 17' by means of S-hook 24.

In FIG. 5, upper leg 13 is telescoped into lower leg 14 and at its lower end, bears against adjustment stop pin 25 inserted in one of adjustment stop holes 26 of lower leg 14. Stop pin 25 is held in place by retainer 27. Adjustment stop holes 26 and 26 are spaced at equal intervals in lower legs 14 and 14' as shown in FIG. 1.

Safety chain 17 is attached near the lower end of lower leg 14 by means of snap fastener 19 anchored by eye-bolt 28 as shown in FIG. 6. Rubber socket 29 serves as a non-marring foot for lower leg 14.

Hinge lugs 31 and 31' of rung clamp 15 provide a connection for legs 12 and 12 at their upper ends. Upper legs 13 and 13 terminate in forked clevis fittings 30 and 30 which connect respectively to lugs 31 and 31' by means of hinge pins 32 and 32'. Hinged movement of legs 12 and 12 about hinge pins 32 and 32, in a plane containing rung 16, is thus possible. As shown in FIG. 7, hinge pin 32 is retained by cotter pin 33, and clevis fitting 30 is fastened to upper leg 13 by drive screw 34.

Rubber bushing 35 in lug 31, and rubber washers 36 surrounding it, provide some flexibility to the connection thereby also permitting limited angular leg movement in a plane perpendicular to the plane of hinged movement. This somewhat flexible connection prevents undue strain in the hinge when legs 12 and 12' are not positioned precisely in a plane through rung 16.

Lugs 31 and 31' are symmetrically located on rung clamp 15 and are ideally located in relatively close proximity to each other. Wider spacing of lugs 31 and 31 departs undesirably from the more ideal single point tripod apex. For wider spacings (e.g. with the legs hinged at or near the ladder side rails) a linkage action results which is stabilized only by the torsional stiffness of the ladder, and has proven to be undesirable.

To accommodate other ladder sizes with this embodiment of the invention, stop pins 25 and 25' are merely relocated at a diiferent level, thereby changing the length of legs 12 and 12 to suit the ladder. The amount of safety chain suitable for large ladders will be excessive for smaller ladders, but may be coiled or doubled back for stowage.

Ladders of somewhat greater length than legs 12 and 12' may be safely supported with the preferred embodiment of this invention. There is no danger in loading the ladder above the clamp in this case provided the load is not cantilevered above the rung clamp at a distance exceeding about one-fourth of the fully extended length of the ladder. Under this support condition the bending stress in the ladder side rails approximates that of a fully extended ladder loaded at its mid-point and resting at its top in the normal mode of usage when leaned.

This invention may also be used with single section ladders in a manner similar to that described for two-section extension ladders.

The most practical material for the tubular legs was found to be mild steel. Suitable electric welded steel tubing is readily available and reasonably economical. Galvanized or aluminized tubing is desirable to prevent rust. Aluminum is also a satisfactory tube material, but it is 7 more costly and oifers no savings in weight for roughly \Vhile only a single embodiment of this invention is shown, other embodiments employing identical or basically similar principles may be devised. It should therefore be understood that this invention is not limited to the specific construction shown and described except as so provided in the appended claims. Those skilled in the art will understand that changes are possible without departure from the principles set forth.

I claim:

A self-supporting extension ladder comprising: a lower ladder section; at least one extensible upper ladder section; a separate fitting engageable with a rung of said upper ladder section; said fitting having fastening means engageable with said rung; two slender legs each with a each having an upper and a lower portion; said upper portions telescoping respectively with said lower portions; said telescoping limited by stop means in each of said legs; said ladder and said legs arrangea'ole in a tripod configuration; said ladder forming one element of said tripod; said legs forming the other two elements of said tripod; said fitting located at the apex of said tripod; a flexible tension link arrangeable in a path extending from said fitting to and around a lower rung of said lower lad der section, continuing to a point near the lower end of one of said legs, continuing to a point near the lower end of the other of said legs, and returning to said lower run said link being attachable to said fitting, engageable with said lower rung, attachable to said one leg, attachable to said other leg, and attachable to itself at said lower rung, respectively.

References Cited by the Examiner UNITED STATES PATENTS 479,051 7/92 Bowser 182-169 548,670 10/95 Stephenson 182-l69 540,643 6/95 Davol 182-170 1,087,286 2/14 Franklin 182-170 2,184,486 12/39 Chew l82-170 FOREIGN PATENTS 1,199,190 6/59 France.

401,656 11/33 Great Britain.

HARRISON R. MOSELEY, Primary Examiner.

REINALDO P. MACHADO, Examiner.

separate hinged attachment to said fitting; said legs,

Images