US2127949A - Folding ladder - Google Patents

Description

P. ZEMAN FOLDING LADD 2 SheetSrS 1 Filed May 8. 1956 Q -ix .g

INVENTOR ATTORNEY Aug. 23, 1938. R E N 2,127,949

- I FOLDING LADDER Filed May s. 1936 2 Sheets-Sheet 2 ll INVENTQR 9/ ATTORNEY Patented Au 23, 1938 UNITED STATES PATENT OFFICE FOLDING LADDER Paul Zeman, New York, N. Y. Application May 8, 1936, Serial No. 78,556

7 Claims.

My invention relates to improvements in folding and extensible step ladders, and has for its object, to provide a new and improved foldable and extensible step ladder.

This is an improvement upon the Folding ladders as shown and claimed in Letters Patent of the United States, Number 2,021,494, granted on November 19, 1935, to the inventor hereof, Paul Zeman.

The object of my invention is to provide a folding step ladder that if of strong, durable and cheap construction, and with a large factor of safety, light in weight, simple, fast, and easy to operate, and which takes very small space to transport or store.

A further object is to provide an extensible and foldable ladder of A shape, with steps either on both sides, or only on one side, in which event, the other side constitutes a brace or a prop.

A further object is to provide several different lengths of a ladder that may be a combination of two or more folding ladders, all of which can be extended or collapsed, individually or as one structure. 3

A further object is to provide an extensible and foldable ladder of A shape with both supports adaptable for collapsing, and adjustable in operative position, on any irregular support or surface, each side of the ladder being on a difierent plane,

as needed on Stairways.

construction. The side frames box form.

are preferably of In the drawings, accompanying this specification and forming part of this application, I have illustrated one practical form of the invention which at the present time, may be regarded as the preferred form, in which drawings:

Figure l is a front elevation of the ladder made in accordance with my invention showing the side frames and the steps in collapsed position, and the single locking means for releasing the ladder from its operative position to its collapsed .position, ready for storage or transportation.

Figure 2 is a side elevation of the apparatus, as shown in Figure 1, showing the front and rear side frames of the ladder gether,

Figure 3 is a sectional view taken about the plane 3-3 of Figure 1, looking in the direction of the arrows at 3--3, showing the cross-section of the side frames when collapsed.

Figure 4 is a sectional view taken at about the plane 4-4 as shown in Figure 1, looking in the direction of the arrows at 4--4showing the single releasing means.

Figure 5 is a side elevation of the ladder showing the front and rear side frames extended, and drawn out at a desired angle to represent the step ladder braced in its operative position.

Figure 6 is an enlarged fragmentary sectional elevation of the ladder showing a pair of the bottom sections, and a pair of the intermediate sections of the side frames of the ladder drawn to-' gether, but not telescoped into folded position.

Figure 7 is a sectional side elevation taken at about the plane l-l, as indicated in Figure 3, looking in the direction of the arrows, showing the telescoped position of the sections when the ladder is folded.

The ladder, in the form illustrated, comprises front side frames 8, and rear side frames '9, joined together at the top by means of a platform it.

Each of the front and rear side frames, 8 and 9, is shown as made up of a number of telescopic sections, and at the bottom provided with resting feet or caps, or shoes i i which may be composed of rubber or other suitable material adapted to fix the ladder in an operative position, or when stored, to protect the surface on which the ladder is standing, and to prevent the ladder from slipping.

The number of telescoping sections is such as to provide the desired length of the ladder for use.

In the form illustrated, there are shown six of such sections, designated by the reference characters, i2, it, it, it, it, and if, respectively, each of which comprises a side standard on each side, joined together by a step, it, i9, 2t, 2!, and 22, at its top, except the top section H, which is joined to the platform it. The lowest section ii, of the side frames 8, and 9, and the first steps l8, are'stationary. The side standards of each section telescope with the corresponding standards of the adjacent sections, as will be understood All the telescopic sections are of the same general construction, each'one being large enough to provide for the telescoping of nearly the full length of the sections above. Means are provided for automatically locking eachtelescoping section when-extended in an operative position, and

for automatically releasing them by a common releasing means in order to perform the telescoping operation of the ladder. Specifically, I have arranged that by manual releasing of one of the telescoping sections, on each front and rear side frame and collapsing of same, the adjacent telescoping section will thereby be released and collapsed automatically in one continuous motion.

In the specific form illustrated, telescoping sections l3, l4, I5, l9, and I1, are provided with aset of double action spring controlled holding dogs 23, which are concealed in a housing 24, formed at the bottom of the telescoping section.

Each set of holding dogs on each of the telescoping sections consist of two pins 25, formed in such a manner that one end is round pointed, and the other end is provided with a head, both of which'pins are pressed with the head in opposite direction against a spring 29. These pins are long enough, that in the normal operative position, they will protrude correspondingly through orifices 21, provided for same in the next adjacent telescoping section to hold same in an operative position.

The upper part of each telescoping section l2, l3, l4, l5, and I6, except the one adjacent to the platform ID, has a box form provided with a cam 28, on both its sides so that as each telescoping section collapses, the cam travels over the round pointed form of the double action spring controlled holding'dogs of the next adjacent section, pressing the same inwardly far enough to permit the holding dogs to be released from the orifices of the next adjacent section to I telescope the ladder into a folded position.

Extending the ladder, from the folded position into the operative position requires drawing out the telescoping sections l3, I4, I 5, l6, and i1, until the holding dogs 23, of each separate section, register with the respective orifice 21, of the adjacent sections. The telescoping sections l2, l3, l4, l5, and I6, are also provided with means to prevent dislocation of the sections, and to further fix them in the operative position. In the illustrations, I have specifically provided the lower part of the respective sections with a rivet 29, which is located immediately above the housing 24, of each section. This rivet moves in a guiding slot 39, .of the adjacent section, and acts as a stop to assure the proper register of the holding dogs 23, into the orifice 21, when the rivet 29, engages the end of the guiding slot 39.

In order to secure uniform and proper unfolding of each set of opposing steps, [9, 20, 2i, and 22, means are provided for coordination between each set. I have shown by reference character 3|, one of such means, comprising a pin 3|, on one side of the step and groove (3Ia) on the respective opposing step, through which they are associated while unfolding is being performed.

The releasing mechanism for the holding dogs 23, as represented in the illustration, comprises special box sleeves 32, which are slidingly mounted at the top of each telescoping section l2. They are arranged to permit the simultaneous release of the holding dogs of the four lowest telescoping sections l2, when the apparatus is to be folded.

The box sleeves 32, are provided with a cam 33, on each side which is so designed that it is free from the holding dogs when the ladder is extended or in an operative position, but so that when the sleeve is depressed, it will press the pin 25, inside the side frame'to release it; whereupon 75 the next adjacent section collapses followed by sections l4, ll, l9, and I1, each following the other as its holding dog is in turn released, thus folding the ladder into its collapsed position.

The bottom surface of the lowest step ll, upon which is provided a socket 34, into which is mounted a bolt 33, projecting downwardly, passing through bracket 39, which is firmly connected on one side with a box sleeve 32; and a spring 31, surrounding the bolt. presses upwardly upon the bracket 36, to hold the sleeve in its raised position. This bracket also carries an eye 33.

A wire 39, has two branches pivoted together, each having two arms and is diagonally arranged and connected to the four eyes 38, so that it connects and operates all four sleeve portions 32, simultaneously. At the central point is a foot pedal 40, for operation of the wire 39.

Two front side frames 8, and two rear side frames 9, are rigidly connected and fixed by a bar 4|, between the lowest telescoping sections I2, provided by a locking device 42, adjacent to the side frames in order to keep them together when the ladder is being telescoped and carried in a folded position. This bar also provides for an additional bracing, giving rigidity to the ladder in the operative position.

A further bracing and rigidity of the ladder is, provided for by means of the wire 39, to take care of the forces in tension, and by two hinged rods 43, connecting the two sides of the corresponding pair of front and rear side frames at such relative space and distance above the wire 39, to take care of the forces in compression or thrust, and also to fix the desired angle of the ladder in operative position. Each hinged rod 43, is held extended by a spring locking device and may be released by pulling a pin 44, in the middle, between each pair of the hinges 43, so as to allow the hinge rods to be folded or extended, as may be required when the ladder is to be folded or fixed in an operative position.

When the ladder is in a collapsed and folded position, it is secured in such a position by the locking device or means, one of the forms being as illustrated by a strap 45. attached to the platform i9, and buckle 48, attached to the lowest step l9, making it ready for transportation.

Other changes may be made within the scope of the appended claimswithout departing from the spirit of the invention, and I do not, therefore, limit myself to the particular construction shown.

Having thus described my invention, I claim and desire to secure by Letters Patent:

1. In a collapsible and extensible ladder in combination, a series of pairs of telescoping sections, with steps mounted thereon, a locking means, carried by each of the telescoping sections to lock it in an extended position byengaging the adjacent section, manually operable releasing means for releasing one of said locking means, and means carried by each section for releasing the locking means of the adjacent section.

2. In a collapsible and extensible ladder in combination, a series of pairs of telescoping sections, with steps mounted thereon, a spring holding dog carried by the lower end of each of the telescoping sections in such a position to engage the adjacent section when the sections are in an extended position, a cam carried by each of said sections operative on collapse of said section for releasing the locking action of the holding dog of the adjacent section, and manual means for the holding dogs i'rames, and connecting the said lowermost sections togetherl thrust members. connecting intermediate sections ct said front and rear side frames; said thrust members and said releasing means oi such relative length, and at such relative distance apart, that said thrust members are in compression, and said releasing-means bracing the action of the telescoping sections from sagging inwardly toward each other.

4., In a collapsible and extensible ladder in combination, a seriesoi' pairs of telescoping sections with steps mounted thereon, a locking means carried by each of said sections to lock it in an extended position by engaging the 'ad- I Jacent member; a box sleeve in such a proportion to flt around and be associated with the upper part of each of the bottom telescoping sections of the frame, provided with a cam, and means also associated with each of the bottom sections by which all of the said box sleeves may be operated simultaneously, thereby simultaneously releasing all the lowest holding dogs, and means upon each upper section for releasing the locking means of the next adjacent section above when said upper section is collapsed thereby.

5. In a collapsible ladder in combination, a series of pairs of telescoping sections, a step rigidly connecting the members 01- each pair, a

withdraw the same.

locking means carried by the bottom of each step of said sections to engage a recess in the next adjacent section below when said sections are in extended position and a treadle situated below said lowermost step connected to withdraw the locking mechanism of the next adjacent step above to permit collapse of the same when said treadle is depressed.

6. In a collapsible ladder in combination, a seriesoi' pairs 01' telescoping sections, a step rigidly connecting the members of each pair, a locking means carried by the bottom oi each step of said sections to engage a recess in the next adjacent sections below when said sections are in extended position and a treadle situated below said lowermost step connected to withdraw the locking mechanism 01' the next adjacent step above to permit collapse of the same when said treadle is depressed, said ladder being-arranged whereby on depression oi said treadle said ladder may be completely collapsed.

7. In a collapsible ladder in combination, a series of pairs 01 telescoping sections, a step rigidly connecting the members of each pair, a locking means carried by the bottom of each step of said sections to engage a recess in the next adjacent section below when said sections ,are in extended position and a treadle situated be- PAUL zEMAN.

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