US2647676A - Ladder - Google Patents

Description

Aug. 4, 1953 LADDER Filed Feb. 15, 1947 2 Sheets-Sheet. l

INVENTOR @7529 NHP/EC mlfik/ ATTORNEYS P. A. NAPIECINSKI 2,647,676

g- 3 P. A. NAPIECINSKI 2,647,676

LADDER Filed Feb. 15, 1947 2 Sheets-Sheet 2 INVENTOR I E'rE e 4 NflP/EC //v5/ ATTORNEYS f It is another object of the "in which the Patented Aug. 4, 1953 UNITED STATES PATENT OFFICE Peter A. Napiecinski, Wauwatosa, Wis. Application February 15, 1947, Serial No. 728,921

, provide a ladder alternatively usable as a straight ladder, or as a double step ladder, the steps on both sides of which are simultaneously available for use, whereby two persons may work upon the ladder simultaneously, if desired, as in the picking of fruit or the decoration of a room. Another advantage of such a ladder lies in the fact that when the ladder is-in use to support scaffolding, the operator does not, need to scramble around the scaffolding to ascend the ladder, for he may support the scaffolding on a step of one section of the ladder, leaving the other section free and unobstructed for ascent.

invention to hingedly relate the component sections of the ladder in such a manner as to provide, at or near the hinge pintle, powerful clamp means for holding the parts in selected positions of adjustment.

More specifically, it is an important object of the present invention to provide a ladder of the indicated type with a section having steps so formed as to be suitably adapted for use either when the ladderis straight, or as a step ladder.

Still other objects concern the ladder hinge hardware and its construction, and the manner rails are braced and the steps are formed.

These and other detailed objects will be more apparent from the following description of the invention, reference being made to the accompanying drawings.

In the drawings:

Fig. 1 is a view in perspective showing the ladder extended for use as a straight ladder.

Fig. 2 is a view on a somewhat larger scale showing the component ladder sections partially folded to receive mutual support for use as a step ladder.

Fig. 3 is a fragmentary detail view of the hinge portion of the ladder showing the component sections folded for storage.

Fig. 4 is a fragmentary detail view on an enlarged scale taken in section longitudinally through the hingedly connected sections of the ladder.

Fig. 5 is a detail view in perspective showing 2 Claims. (01. 22s,2s)

in separated positions the hardware elements providing the hinge.

Fig. 6 is a detail view taken in longitudinal central section through the hingedly related portions of the ladder.

Fig. 7 is a view similar to Fig. 4 on a slightly reduced scale, showing a modified embodiment of the invention.

Fig. 8 is a fragmentary detail view in side elevation of the hinge structure used in Fig. '7, portions of the outer disk being broken away.

The'ladder comprises two sections, A and B, which are similar in width and length, but differ in respects hereinafter noted. Section A is generally conventional, comprising side rails l, 8, steps 9, and stay bolts II]. The steps are preferably set obliquely with reference to the rails so as to be substantially horizontal in use, whether the ladder is extended to rectilinear form as shown in Fig. 1, or is employed as a step ladder in the position shown in Fig. 2. The top step II is preferably of materially increased width, as best shown in Fig. 6, and is held by angle brackets I2 in the manner indicated in Figs. 1, 2, 4 and 6. The brackets, as Well as the step I I, project from the rails l and 8 so that when the device is in use as a step ladder, the top step II will serve both sides.

Section B of the ladder comprises rails 10, and steps which are wedge-shaped in cross section, as best shown in Figs. 2 and 6. Instead of fabricating hollow steps made of angularly connected boards, I prefer to make the steps 90 of a single, wedge-shaped block having tread surfaces 9| and 92 disposed at an acute angle to each other, the block being provided in its broad inner end with a kerf through which extends the stay bolt I0, identical with that used in section A.

The sections A and B of the ladder may be, and preferably are, connected by special hardware hinging such sections and best shown in Figs. 2, 4 and 5. The rails l, 8 of section A of the ladder are provided near their upper ends with channels I5, I6, each of which has a disk I! integral with it, as best shown in Figs. 4 and 5. Each of the rails I0, 80 of section B is provided with a similar channel I50, I 60, each such channel having an integral disk portion I ll) preferably corresponding substantially in diameter to the disk portion IT. The disks are associated in pairs.

Welded at I3 to each disk I70 is the head portion I9 of a threaded stud 20, which may be tubular if desired. This stud projects through an aperture 2| in the associated disk I1 and serves as a fulcrum pin or pintle upon which the parts A and B of the ladder are pivotally hinged. A clamping means comprises nut 22 in threaded engagement with each stud 20 and provided beyond the end of the stud with transverse holes at 23, in which the rod 2 1 is mounted. The rod is headed at 25, 28 to secure it against loss, and it serves as a lever for tightening the nut, whereby the disks ll, 1'!!! and I6, 108 may respectively be clamped together in tight frictional engagement.

Each of the outer disks l6, i1, is preferably embossed outwardly to provide a detent recess 21 with which embossed ribs 28, 29 and 30 on the respective inner disks [6%, 170 are selectively engageable to define pre-determined relative positions of the sections A and B of the ladder. When the sections A and B are aligned, as shown in Fig. 4, the rib 28 registers with the embossed recess 21. When the parts are positioned for use as a step ladder in the manner indicated in Fig. 2, the rib 29 will register with the recess 21, and when the ladder parts are folded for storage, as in Fig. 3, the rib 39 will register with the recess 21.

With the clam ing pressure of nuts 22 slightly relieved from the extreme pressure used to maintain the parts in position of use, the engagement and disengagement of the several ribs with the respective recesses will serve as impositive detent means defining the desired positions. When a given position is reached, a fractional turn of the nut will fix the sections A and B in such position. When it is no longer desired to have the ladder parts in the position to which they have been adjusted and clamped, a fractional turn of the nut at each side of the ladder will release the hardware parts for relative movement, subject, of course, to the slight impositive resistance involved in releasing the respective detent ribs from the respective recesses.

The modified embodiment shown in Figs. 7 and 8 is preferred for many purposes. In the type of clamp hinge there illustrated, the mounting parts it and 166 may be identical with those already described. The disk ill carried by mounting plate [6 is offset, as previously described, to comprise the outer disk of the hinge assembly. The pintle comprises a short bolt 20! passing through disk ill and the inner disk [12. The clamp, however, is separate, comprising a bolt 20?. with its head interiorly disposed, and its shank extending through the slot iii in the inner plate 112. The lock nut 22 and its operating lever 2'4 may be identical with the clamping nut already described. The advantage of this arrangement lies primarily in the fact that the clamping pressure is exerted at a point radially remote from the pintle, and hence operates with greater mechanical advantage to prevent relative rotation between the disks.

As a further means of maintaining the sec- 'tions A and B secure when the parts are adiusted for step ladder usage, I may provide chains 32, 33 attached to one of the sections and provided with snap hook means at 36 for releasable connection with eye The oblique position of the top surface element bolts on the other section. 6

" longitudinal kerf intermediate 9| of each of the steps of section B is adapted to provide a substantially horizontal surface when section B is adjusted to a position for step ladder usage, as in Figs. 2 and 6. It will, however, be apparent that the angular obliqueness of this surface would be exactly wrong when the ladder is adjusted to the extended position shown in Fig. 1. In the extended position of the ladder, the oppositely oblique angularity of the step element 92 becomes approximately horizontal and is the surface exposed for use, this section of the ladder being inverted in its Fig. 1 position, as compared with its Fig. 2 position. Thus, a safe and secure footing is provided for the user of the ladder in both of the mutually inverted positions of section B, and in both positions, the invertable section is securely clamped, not only frictionally by the large surfaces of the disk, but by the engagement of the appropriate rib of one disk in the channel of the other.

I claim:

1. A ladder comprising sections and a hinge connecting said sections in two alternate positions of use, said hinge being provided with means locking the sections in one position as an extension ladder and in another position as a step ladder, one of said sections being upright in both said positions and having rails and steps obliquely related to said rails to be horizontal in said upright position, the other said section being upright in one position and inverted in the other position and having rails and steps of wedge shaped form having opposite tread surfaces, one said tread surface being of the same angle to its rails as the steps of the section first mentioned whereby to be horizontal when in upright position, the other said tread surface being oblique to said rails at a different angle to be horizontal when said section is in said inverted position.

2. The device of claim 1 in which the said steps of wedge shaped form have a narrow edge along corresponding edges of the rails and a wide edge along opposite corresponding edges of the rails, said wider edge being provided with a said oblique tread surfaces, and a tie bolt in said kerf and connecting the rails therethrough.

PETER A. NAPIECINSKI.

References Cited in the file of this patent UNITED STATES PATENTS

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