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Publication numberUS3291258 A
Publication typeGrant
Publication dateDec 13, 1966
Filing dateNov 24, 1964
Priority dateNov 24, 1964
Publication numberUS 3291258 A, US 3291258A, US-A-3291258, US3291258 A, US3291258A
InventorsTwilley Ruth I
Original AssigneeTwilley Ruth I
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Telescopic ladders
US 3291258 A
Abstract  available in
Images(4)
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Claims  available in
Description  (OCR text may contain errors)

DeC- 13, 1956 A. J. TWILLY 3,291,258

TELESCOPIC LADDERS Filed Nov. 24, 1964 4 Sheets-Sheet l INv'ENf/Ula.

. ARCH/5 rf ruf/MEX Dec' 13, 1966 A.J.TW1LLEY TELESCOPIC LADDERS 4 Sheets-Sheet INVENTOR.

6o E'fgawwp Filed Nov. 24, 1964 Dec. 13, 1966 A.J. TWILLEY 3,293,258

TELESCOPIC LADDERS Filed Nov. 24, 1964 4 Sheets-Sheet S Dac. i3, l966 A, J. TWILLEY 3,29L258 TELESCOPI C LADDERS Filed NOV. 24, 1964 4 Sheets-Sheet 4 F W 4Z l 44 t@ J0 i /Z if A r raw/yf United States Patent 3,291,258 TELESCOPIC LADDERS Archie J. Twiiley, 2280 Viewmont Way W., Seattle, Wash.; Ruth I. Twilley, executrix of said Archie J. Twilley, deceased Filed ov. 24, 1964, Ser. No. 413,524 18 Claims. (Cl. 182-211) The present invention relates to ladders, and more particularly to telescopic extension and stepladders which are shallow or thin as well as short when retracted, making them easy to handle, and capable of being stored in small spaces, during periods of nonuse.

Known conventional extension ladders are composed of two or more ladder sections in which each ladder section lies substantially wholly outwardly of the adjacent ladder section when the ladder is retracted. Essentially, the depth dimension or thickness of a retracted conventional extension ladder is substantially equal to the combined depths of the stiles of each of its sections. Examples of extension ladders of this type are disclosed by the following U.S. patents: Hummel 2,147,370; Pearl 2,760,706; and Larson 2,957,543.

By way of typical example, in a five section extension ladder of the conventional type, wherein the average depth of the stiles is about three and one-half inches, the thickness of the retracted ladder would be about fifteen to seventeen and one-half inches. In contrast, a ve section extension ladder constructed according to the present invention, having the same average stile depth (i.e. about three and one-half inches), would have a retracted depth of only about six inches.

Accordingly, a principal object of the present invention is to provide a multisectional extension ladder in which the stiles or side members of the intermediate and top sections are successively telescopically movable into a substantially wholly contained position within the stiles or side members of the bottom section, such that the retracted thickness of the ladder substantially equals the depth of the stiles of the bottom section.

The stiles of ladders according to the present invention are of inwardly opening channel configuration. They are composed of relatively thin panel portions. When the ladder is retracted the panel portions of each stile extend in juxtaposition with similar panel portions of the adjacent stile of the adjoining ladder section (r sections). In essence, the relatively thin depth characteristic of ladders constructed according to the present invention can be attributed to the unique design and judicious arrangement of the stile panels, the arrangement of the rungs relative to such panels, and the manner of attachment of the rungs to the stiles.

Extension ladders according to the present invention constitute improvements over the extension ladders disclosed in the aforementioned prior patents, and also constitute improvements over the ladder disclosed in Hofele, U.S. Patent No. 244,059. The Hofele ladder is of the telescopic type, but the lower and intermediate ladder sections are of what may be termed a box construction. Each such section comprises four corner posts interconnected at the sides and along the front and back by rungs. A tier of short rungs and a series of cross braces interconnect each side pair of posts. Two tiers of longer rungs, one at the front and one at the back, interconnect the two side assemblies. The bottom section and each intermediate section in effect boxes in the section above it, and the retracted ladder possesses a relatively large depth dimension.

It is a further object of this invention to provide an improved ladder which may serve both as a stepladder and as an extension ladder, which is capable of being easily converted from one type of ladder to the other, with but a minimum of effort, and which functions ediciently in either capacity.

Another object of this invention is to provide a ladder of the above-described character which is constructed to withstand a relatively heavy loading, but which at the same time is relatively light in weight and can be easily handled.

A still further object of this invention is to provide a ladder of the above-described type which is relatively simple in construction and can be economically manufactured.

These and other features and characteristics of extension and stepladders according to the present invention will be apparent from the following description and accompanying illustration of typical embodiments thereof.

Reference will now be made to the drawing wherein like letters and numerals refer to like parts, wherein the gures are approximately to scale, and wherein:

FIG. 1 is a perspective view of a retracted five-section extension ladder constructed according to the present invention, such View showing the relatively thin profile of such ladder when the same is retracted;

FIG. 2 is a cross-sectional View taken through the stiles at one side of the retracted ladder, with the opposite stiles and parts of the rungs omitted, such View being taken substantially along line 2 2 of FIG. l, and showing the nesting arrangement of each relative upper stile in the stile below it, and the relative arrangement of the rungs to each other and to the stiles;

FIG. 3 is a perspective view of the ladder of FIGS. l and 2, such view showing the ladder dismantled and the several sections standing apart from one another;

FIG. 4 is an enlarged scale perspective view of a preferred form of fitting for use in securing the rungs to the stiles, such View showing the fitting attached to a panel portion of a stile, and an end portion of a rung in spaced relationship with such fitting;

FIG. 5 is a view similar to FIG. 4, but showing the end portion of the rung positioned over and crimped onto the dowel portion of the tting;

FIG. 6 is a fragmentary cross-sectional View taken through overlapping portions of the stiles at one side of adjoining ladder sections of the ladder of FIGS. 1-3 when the same is extended, such view showing in detail a preferred form of apparatus or locking the extended ladder sections together;

FIG. 7 is a view like FIG. 6, but showing the locking apparatus in a released position;

FIG. 8 is a view similar to FIG. l, but of a second form of ladder constructed according to the present invention, which ladder consists of three sections;

FIG. 9 is a view like FIG. 2, but taken through the ladder of FIG. 8, substantially along line 9-9 of FIG. 8;

FIG. 10 is a view like FIG. 3, but pertaining to the ladder of FIGS. 8 and 9, such view showing that the top ladder section is divided into major and minor parts which are pivotally connected together, such construction of the top ladder section, together with certain constructional features of the ladder section immediately below it, making it possible to convert the ladder from an extension ladder to a stepladder;

FIG. ll is a fragmentary View of the upper portion of the ladder of FIGS. 8-l0 when the same is standing in the form of a stepladder, such view showing the two positions of a brace member which is employed when the ladder is used in a stepladder capacity;

FIG. l2 is a fragmentary side elevational view taken in the overlapping region of the stiles of adjoining ladder sections, such view showing a modified form of means for locking the ladder sections together, such means ncluding a hook that in FIG. 12 is shown in a disengaged position;

FIG. 13 is a view like FIG. 12, but showing the hook that is pivotally attached to the relatively upper section being engaged or hooked over a rung of the relatively lower section; and

FIG. 14 is a view like FIGS. 12 and 13, but showing another position of the locking mechanism.

Referring more specifically to the drawing, FIGS. 1-7 relate to a typical extension ladder constructed according to the present invention. Such ladder 10 is shown in FIGS. 1, 2 and 5 to comprise five ladder sections, designated from top to bottom 12, 14, 16, 18 and 20. Each ladder section comprises a laterally spaced pair of stiles or uprights, and a single tier of rungs R interconnecting between them. The stiles of at least the bottom and intermediate sections are inwardly opening channels formed of a plurality of panel portions. Commencing at the top, the stiles of each ladder section are telescopically received in the Stiles of the section immediately below it. When the ladder is retracted (FIGS. l and 2) the stiles of the intermediate and top ladder sections are substantially wholly contained in (or nested in) the stiles of the bottom ladder section. The ladder sections will now be individually described.

The rungs R of the top section 12 substantially abut at their ends the web portions 22 of the stiles of such section to which the rungs R \are perpendicularly related. Side flanges 24, 26 are formed integral with and extend inwardly from the longitudinally extending front and rear edges of the web portions 22. Stiffening lips 28, 30 are formed integral with and extend inwardly from the side flanges 24, 26.

The stiles of ladder section 14 include `a web 32, a pair of side anges 34, 36, a stifening lip 38, and a rung mounting and stiffening ange 40, all of which are preferably planar, as illustrated.

The stiles of ladder sections 16 each comprise a web 42, side flanges 44, 46, a stilening lip 48, \and a rung mounting and stiffening ilange 50.

In somewhat similar fashion, the stiles of ladder section 18 each comprises a web 52, side anges 54, 56, a stiiening lip 58, and a rung mounting and stiflening flange 60.

The stiles of bottom section 18 each include a web 62, side flanges 64, 66, a stilfening lip 68, and a rung mounting and stiffening flange 70.

As shown by FIG. 2, the webs 22, 32, 42, 52, 62 extend in closely spaced parallelism. The side flanges 24, 34, 44, 54, 64, also extend in closely spaced parallelism, and are each shown to be right angularly related to its web. As also shown by FIG. 2, side anges 26, 36, 46, 56, 66 extend in closely spaced parallelism, and are each right angularly related to its web.

The stilening lips 28, 38, 48, 58, extend in closely spaced parallelism, and together with stiffening lips 30 and 68 are preferably arranged to extend in Widely spaced parallelism with the webs 22, 32, 42, 52, 62, and are each preferably right Aangularly related to the side llange from which it projects.

Each rung mounting and stiifening flange 40 extends inwardly a substantial distance from the side flange 36 to which it is attached, and terminates closely adjacent the rungs R of ladder section 12. Each rung mounting and stiifening flange 50 extends inwardly from the side ange 46 to which it is attached a much lesser amount, and terminates closely adjacent the rungs R of ladder section 14. As clearly illustrated, the flanges 50 are situated inboardly of the anges 40, resulting in the rungs R of ladder section 16 being shorter in length than the rungs R of the ladder section 14. Since the rungs R of ladder section 12 are attached to the rungs 22 of the stiles of such section, they are longer than the rungs R of ladder section 14.

The anges 60, 70 both project outwardly from the side flanges to which they are integrally attached, but in opposite directions. The rungs R of ladder section 18 are in close parallelism with the rungs R of ladder section 16, and the rungs R of ladder section 20 are separated from the rungs R of ladder section 12 by the nested group of side tlanges 24, 34, 44, 54 and stiffening lips 28, 38, 48, 58.

As will be readily appreciated, it is the judicious placement and arrangement of the rung mounting and stiftening flanges 40, 50, 60, 70 which make possible the close spacing of the tiers of rungs R. This together with the nested arrangement of the stiles of the intermediate and top ladder sections in succession within the stiles of the bottom section 20 is responsible for the relatively shallow depth of the ladder 10 when it is retracted.

By way of typical example, and for the purpose of illustrating the s-hallow depth characteristic of ladders constructed according to the present invention, in a ve section ladder of the type illustrated -by FIGS. 1-7, the depth dimension of the stiles for bottom ladder section 20 (i.e. the width of the web 62) may be about four and one-half inches (4l/2") and the rung depth or thickness about three quarters of an inch (34). This gives the ladder when retracted a total dept-h of `approximately six inches (6). This dimension is the sum of the depth (4l/2") of the stiles of section 20 and the thickness (1%1 each) of the rungs of sections 18, 20 (FIG. 2) The ladder sections may measure approximately four feet (4') each in length. Taking the necessary overlap between sections into consideration, such ladder may be adapted to be extended out to a length of about sixteen feet (16').

As clearly shown by FIG. 1, the retracted ladder makes a compact package and may be easily carried or stored in the trunk space or the back seat of most modern automobiles. Owing to this capability, the ladder illustrated by FIGS. 1-7 may be appropriately termed a trunk ladder.

A typical manner of attaching the rungs R of ladder section 12 to the webs 22 of such section, and the rungs R of ladder sections 14, 16, 18, 20 to the rung mounting and stiften-ing flanges 40, 50, `60, 70, respectively, of such sections, is shown by FIGS. 3 and 4. In such figures the rungs R are shown to be tubular. The connector 72 is shown to include a thin relatively at base 74, anda dowel 76 projecting inwardly (relative to the center of the ladder 10) from said base 74. The base 74 is riveted or otherwise suitably attached to the web or ilange onto which it is to be anchored. The external configuration of the dowel 76 is substantially Iidentical to the internal configuration of the rung R. Preferably, the dowel 76 is made to be tight tting in the rung R, so that some force is required to drive the two together. The dowel 76 is formed to include at least one recess 78, and when the rung R is in place, it is crimped in the area of each recess 78 (FIG. 5) for the purpose of securing the lrung R on the dowel 76.

As shown by FIGS. 1 and 3, a combined pole bracket land brace 80 may be located at the upper end of the upper ladder section 12. The 'brace 80 is shown to consist of a straight member 82 which at its ends overlaps and is secured to the upper end portions of side anges 26. The upper end portions of stitfening lips 3) are cut away to make room for the end portions of straight member 82. The brace 80 lalso includes a trihedral member 84 which is attached lat its ends to the 4upper end portions of side flanges 24. The upper end portions of strengthening l-ips 28 are also cut away to make room for the end portions of rmember 84. A rivet 86 or the like secures the midportion of member 82 to the midportion of member 84. As will be readily appreciated, when the ladder is to be used against a telephone pole, tree, or the like, the trihedral member 84 rests against the curved surface of such object, giving the ladder better than a point support at its upper end.

As also shown by FIGS. 1 and 3, the lower ends of the stiles for the lower ladder section 20 may be provided with support feet 88. An L-shaped member 90 is shown to be attached to the lower end portion of each stile of ladder section 20, giving such stiles a box-like crosssection at such location. The support feet comprise a pair of laterally spaced, triangular side plates and a bottom plate i-nterconnecting the base portions of said side plates. The upper ends of the side plates are pivotally connected to the lower end portions of the stiles for ladder section 20, preferably by a pin extending through the webs 62 and the L-shaped members 90. A ground engaging pad of rubber, knurled aluminum, etc. may be secured to each bottom plate.

A preferred ymechanism for locking the lladder sections together in an extended position will now be described.

FIG. 1 shows that each relatively upper section extends a little above the upper terminal of the ladder section immediately below it. A 1hand releasable mechanism 92 for locking together ladder sections 12 land 14 when the ladder is extended is shown to be located in the upper extension of the Stiles for ladder section 14. A like mechanism 94 is located in the upper extension of ladder section 16. Lock mechanism 94 serves to lock together ladder sections 14 and 16 when the ladder is extended. The mechanism for locking together ladder sections 16 and 18 is located in the upper extension of the stiles for ladder section 18, and is designated 96 in FIGS. l and 3. The loc-k mechanism for locking together ladder sections 18 and 20 is positioned on the side tlanges 66 of the Stiles of ladder section 20, and is designated 98 in the drawing.

The ladder is extended by pulling each relatively upper section out from its nested position within the section below it. As the top section 12 is moved relatively upwardly, openings 1110 in the webs 22 of the Stiles of such top section 12 are moved into a position wherein they are engaged by a locking plug or detent forming a part of the locking mechanisms 92. The same is true with respect to each adjoining pair of ladder sections below ladder section 12.

FIGS. 6 and 7 are fragmentary sectional views taken through the stiles of ladder sections 14 a-nd 16. Referring first to FIG. 6, the locking mechanism 94, which is identical in construction to locking mechanisms 92, 96, 98, is shown to consist of a flat, elongated bar spring 102 attached at one end to the web 42 by a -rivet 104 o-r the like. A detent 106 is located slightly inwardly from the opposite end of spring 1112. An opening is formed in web 42, and the detent 106 extends through such opening. Another opening 168 (FIG. 3) is formed in the webs 32 of ladder section 14. The openings 1G18 are in the path of the respective plug elements 1116, and when ladder sectio-ns 14 and 16 are moved relatively apart as the ladder is extended, the openings and the detents 166 are ymoved relatively together, wit-h the detents 106 eventually entering into the openings 10S to be engaged thereby and prevent further movement of the ladder sections. FIG. 6 illustrates the lock position of the locking mechanism 94, wherein the detent 166 is engaged by an opening 108. A keirf or slot 110 may be cut in the upper portion o'f the detent 166. This slot 110 engages the lportion of panel 32 that immediately borders the opening 108 on the upper side thereof.

The end of spring element 102 opposite the pin 104 is curled outwardly so as to form a handle 112. The locking mechanism 94 is unlocked by the user grasping the handle 112 and pulling the detent 106 out of engagement by the opening 108. This allows the ladder section 14 to be telescoped into, or to be completely removed out from, the ladder section 16. FIG. 7 shows the locking mechanism 94 in an unlocked position. Spring member 1116 may be pivotally attached to the panel 42 by the pin 104 so that the detent 106 may be pivoted out of alignment with the opening in panel 42 when it is desired that the locking mechanism not function.

FIGS. 8-14 relate to a modified form of telescopic ladder according to the present invention. Such ladder, designated 114, is adapted to be both an extension ladder and a stepladder. Ladder 114 is shown to comprise three ladder sections, designated (from top to bottom) 116, 118, and 1241. Ladder sections 116, 118, are essentially identical in construction with latter sections 12, 14, 16, respectively of the ladder shown by FIGS. l-7, except that they are longer. Due to this substantial identity in construction, the reference character designation given the panel portion of the stiles of the ladder shown by FIGS. 1 7 are also used in conjunction with the ladder shown by FIGS. 8-14.

FIGS. 8-14 also disclose a modified form of mechanism for locking adjacent ladder sections together when the ladder is extended. FIGS. 1214 present a succession of fragmented views taken in the vicinity of the locking mechanism for locking ladder sections 116 and 118 together. Such mechanism comprises a hook 122 that is pivotally connected to web 22 at a point below the lowermost rung R of ladder section 116, the pivot point being designated 124 in the drawing. The hook 124 extends upwardly and inwardly from the pivotal connection 124 to contain the said lowermost rung R of ladder section 116 in its open throat area. A spring 126 is attached at its upper end to hook 122 at point 128. The spring curves rst upwardly and then downwardly from point 128 in inverted U fashion. The spring 126 takes a wrap around pivot pin 124 and then extends along and is secured to an arm 13). Arm 131i, which is also mounted for pivotal movement by pin 124, will be hereinafter described in greater detail. The upper inboard edge of hook 124 is convex in shape and serves as a cam surface when the ladder sections 116, 118 are being moved relatively together from the position illustrated by `solid lines in FIG. l2. Referring to FIG. 12, as the rung R attached to ange 32 moves relatively downwardly and closer tothe rung R attached to ange 22, such former rung R contacts the cam surface 134 on hook 122, and causes hook 122 to swing into the position depicted by broken lines in FIG'. 12. As soon as the upper portion of hook 122 clears the rung R attached to ange 32, the hook 122 is returned to the solid line position by the spring 126, at which time the hook 122 engages both of the rungs R, as is illustrated by FIG. 13. In referring to FIG. 13, it is to be remembered that ladder section 118 is the relatively lower section, and between the two sections 116, 11S, it is the relatively upper section 116 that tends to slide downwardly and must be held. Such downward movement of ladder section 116 is prevented by the fact that hook 122 extends over and engages the rung R of ladder section 118. It can clearly be seen that ladder section 116 cannot move downwardly as long as the rung R of ladder section 11S is in the way of the upper portion of hook 122. Of course, when it is desired that the two ladder sections 116, 118 be moved relatively together, the hook 122 can be moved by hand to a position wherein it no longer engages the rung R aixed to ladder section 118.

As also shown by FIG. 13, when ladder section 118 is moved relatively downwardly, or ladder section 116 is moved relatively upwardly, from the position shown by solid lines in FIG. 13, the rung R attached to panel 32 strikes arm 13d and pivotally moves it against the force of the lower portion of spring 126 into the position shown by broken lines in FIG. 13, wherein it is out of the way and does not prevent further relative movement of the rung R attached to panel 32.

Referring now to FIG. 14, when the ladder sections 116, 118 are moved in the opposite sense, i.e. ladder section 118 is moved relatively upwardly and ladder section 116 is moved relatively downwardly, and the rung R attached to panel 32 is initially below the arm 130, such arm 130 is rotated clockwise, as pictured, by said rung R. The arm 136 moves against a shoulder 136 on hook 122 and in that manner pushes the hook 122, causing it also to swing in the clockwise direction, as pictured in FIG. 14. By the time that the rung R has cleared the upper end of arm 130, it will be adjacent and able to make contact with the cam surface 134 so that when the arm 130 snaps back into the position shown by solid lines in FIG. 13, the hook 122 will not immediately follow it. This enables the rung R of ladder section 118 to move relatively upwardly without being engaged by the open throat area of the hook 122.

Referring now to FIG. 10, ladder section 116 is shown to be divided into two parts, which hereinafter will be termed its major and minor parts. The major part 140 is pivotally connected to the minor part 142 by means composed of a pair of substantially V-shaped plates 144, and pivot pins 146, 148 pivotally connecting the upper and lower end portions of the plates 144 to the major and minor parts 140, 142 of the ladder section. When the ladder 114 is used as an extension ladder, the minor part 142, the plates 144, and the lower end portions of the major part 140 are housed in the upper portion of ladder section 118, and the articulated construction of ladder section 116 plays no part in the function of the ladder.

Referring now to FIG. 11, a block 150 serving as a stop member, is secured to the inside surface of webs 22. A similar block or stop member 152 is secured to the outboard surface of panels 40. The blocks 150, 152 prevent the removal of the top ladder section 116 entirely out from engagement by the intermediate ladder section 118, but do allow the major part 140 of said ladder section 116 to be removed from engagement by the ladder section 118. The major section 140 may be then pivotally moved into a position wherein it makes an acute angle with the intermediate and bottom ladder sections 118, 120.

A brace 154 is pivotally connected at its lower end to ange 40 of each stile of ladder section 118 (FIG. 10). Each brace 154 is straight throughout the greater portion of its length, but angles to one side of its upper end. A pin 156 is provided at the upper end of each brace 154. When the braces 154 are not being used, they occupy the position shown by broken lines in FIG. l1, and by solid lines in FIG. 10. In such position, the pin 156 is engaged behind a lip 158 that extends in a plane that is generally parallel to the general plane of the rungs R. When the braces 154 are to be used, they are grasped at their upper ends and pulled slightly inwardly toward the center of the ladder section 118 until the pin 156 clears the lip 158. The braces 154 are then swung downwardly into a near horizontal position, and the pin 156 is engaged into a keyhole opening 160 formed in web 22 of the stiles for the ladder section 116 in its major part. Preferably, the pin 156 has an enlarged head. The enlarged head is inserted into the large circular portion of the keyhole opening 160 and then the brace is moved downwardly so that the shank portion of pin 156 is engaged by the slot portion of the keyhole opening 160. The enlarged head is wider than the slot and thus cannot pass laterally through the slot.

If ladder 114 is used as a stepladder on uneven ground, or on a slight grade, v'intermediate ladder section 118 may be telescopically moved a slight distance out from its position in bottom ladder section 120 in order to make its side of the stepladder longer. This longer side may then be set in the down-hill position when the ladder is being used on a slight grade, or in the low spot when the ladder is being used on uneven ground.

In FIGS. 8 and 10, the converted U-shaped members 162 provided at the top of ladder section 116 are rub rails. They are rubber covered or smooth surfaced and are provided so that the ladder will not mar the surface against which it leads.

The ladders shown by FIGS. 1-7 and FIGS. 8-14 are but two embodiments of telescopic ladders according to the present invention. As will be readily appreciated, the basic principles involved in the present invention may be found in ladders that differ substantially in construction from the ladders illustrated in the drawing. For example, the stepladder principles may be applied to the tive section ladder illustrated by FIGS. 1-7. Also, it may be desirable to make the ladder in only two or four sections. The rungs R may be made round or in some other shape differing from what is illustrated. Also, it may be desirable to give the stiles, or at least the web portions of the stiles, a somewhat rounded lateral shape, rather than making them planar as illustrated. The locking mechanisms that are illustrated and described are preferred mechanisms for performing the locking function and constitute a part of the present invention. However, it is to be understood that other types of locking mechanisms may be satisfactorily used.

Preferably all parts of the ladders constructed according to the invention, except for the locking mechanism and the fasteners, pivot pins, etc., are preferably constructed from aluminum. The stiles may be brake formed, extruded or cast. Extrusion is preferred. The tubular ones are preferably also extruded. Of course, it is to be understood that materials other than aluminum may be used, and the invention is not to be limited to a particular material, or to a particular mode of manufacture, unless a claim is so limited.

From the foregoing, further variations, adaptations and modifications with respect to telescopic extension and stepladders according to the present invention can be evolved by those skilled in the art to which the invention is addressed, within the scope of the following claims.

What is claimed is:

1. A telescopic extension ladder comprising a top section, a bottom section, and at least one intermediate section, each of said sections including a pair of parallel, laterally spaced stiles and a single tier of rungs extending between and interconnecting said stiles, with the stiles of the top and intermediate sections being telescopically received in the stiles of said bottom section, with the tiers of rungs of the top and intermediate sections being in parallelism with each other and with the tier of rungs of the bottom section, with the s-tiles of the bottom and intermediate sections being of channel form and each comprising a web, a pair of side flanges formed integral with and extending inwardly from the edges of said web, a rung mounting flange formed integral with and extending inwardly from one of said side flanges and extending in spaced parallelism with said webs, and a stitening lip formed integral with and extending inwardly from the other one of said side flanges, and also extending in spaced parallelism with said webs, with the stiles of the top section each comprising a web that extends in closely spaced parallelism with the webs of the stiles of said bottom and intermediate sections, with the ends of the rungs of the said top section being secured to the webs of that sections stiles, and with the ends of the rungs of said intermediate and bottom sections being secured to the rung mounting flanges of the stiles of said sections.

2. A telescopic extension ladder according to claim 1, wherein at least the end portions of the rungs are tubular, and the connector means for such rungs each comprises a thin, substantially planar mounting base, a dowel secured at one end to said mounting base and extending from said mounting base into the adjacent end of its rung, with said rung having an end surface that substantially abuts against the face of the mounting base, with said dowel having an exterior conguration substantially matching the interior configuration of the rung, with at least one recess being formed in the dowel, and with the portion of the rung over such recess being crimped into the notch for the purpose of securing the rung to the dowel.

3. In a telescopic extension ladder, rst and second ladder sections, each comprising a pair of laterally spaced stiles and a tier of rungs extending between and interconnecting said stiles, with the stiles of said rst ladder section being telescopically received in the Stiles of said Second ladder section, with the tier of rungs of Said first ladder section being generally parallel to the tier of rungs of said second ladder section, and with each of the Stiles of the first ladder section comprising a plurality of relatively thin panels including a web and a pair of Side anges made integral with and turning inwardly from Said web, and each of the Stiles of the second ladder section comprising a plurality of relatively thin panels including a web extending outwardly adjacent the web of the adjoining Stiles of Said first ladder section, a pair of side flanges made integral with and extending inwardly from the web of such stile of the second ladder section, outwardly adjacent the anges of the adjoining stile of said first ladder Section, and a rung mounting and stiifening flange made integral with and extending inwardly from one of Said Side anges of such side member of the second ladder section, with the rungs of said second section being Secured at their ends to the rung mounting and stilfening flanges of the Stiles of Said Second ladder Section, and means for locking said first and Second ladder sections together when the ladder is extended, Said means comprising an elongated relatively at and thin Spring element disposed outwardly of, and pivotally connected at one of its ends to, one of said panels of at least one stile of the second ladder Section, and an inwardly projecting detent Secured to the end of Said spring element opposite from the pivotal connection, with an opening for Such detent being formed in the panel portion of the stile to which the Spring element is pivotally connected, and with a Second opening being formed in the adjacent panel portion of the first ladder section, in the path of such detent, so that when the ladder Sections are pulled relatively apart -th'e Said detent and the said opening in the panel portion of the stile of the first ladder section are moved relatively together, and the detent then enters into Such opening and prevents further relative movement of the two ladder sections, Said Spring element further including handle means by which it may be grasped for the purpose of pulling the detent out of engagement from the said opening in the said panel portion of the Stile of the first ladder Section, so that the ladder sections may again be moved relative to each other.

4. In a telescopic ladder, first and Second ladder Sections, each comprising a pair of laterally spaced Stiles and a tier of rungs extending between and interconnecting Said Stiles, with the Stiles of Said first ladder section being telescopically received in the Stiles of said Second ladder section, with the tier of rungs of Said first ladder section being generally parallel to the tier of rungs of said second lad-der section, and with each of the Stiles of the first ladder Section comprising a web and a pair of Side fianges formed integral with and turning inwardly Lfrom said web, Iand ea-ch of the Stiles of the second .f

ladder section comprising a web extending outwardly adjacent the web of the adjoining stile of Said first ladder Section, a pair -of Side anges forme-d integral with and extending inwardly from the web of Such Stile of the second ladder section, outwardly adjacent the side flanges of the adjoining Stile olf said first ladder section, and a rung mounting and stiifening flange formed integral with and extending inwardly from one of Said side flanges of Such stile of the Second ladder Section, with the rungs of Said first ladder section being secured at their ends to the webs of the Stiles of :said first ladder section, and with the rungs of said Second ladder Section being secured at their ends to the said rung mounting and stiffening anges of the Stiles of said second ladder section.

5. A telescopic ladder according to claim 4, further including means f-or locking adjacent ladder Sections together when extended, said means comprising an elongated, relatively fl-at and t-hin spring element disposed outwardly of, and connected at one of its ends to, at least one stile of `each relatively lower ladder Section, and an inwardly projecting detent Secured to the end of said spring element opposite from the connection, with an opening for such detent being formed in the Stile to which the spring member its connected, and with a Second opening being formed in the adjacent stile of the other ladder section, in the path of such detent, so that when the ladder sections are pulled relatively apart the Said detent and said second opening are moved relatively together, and the detent can enter into such opening and prevent further relative movement of the two ladder sections, said Spring elements further including handle means by which it may be grasped for the purpose of pulling the detent out of engagement from said Second opening, for permitting the ladder sections to be moved relative to each other.

6. The combination of claim 4, further including a third ladder section having a pair of laterally spaced Stiles and a tier of rungs extending between and interconnecting Said Stiles, with the Stiles of Said second ladder Section being telescopically received in the Stiles of said third ladder Section, each Stile of the third ladder section compriSi-n'g a web extending -outwardly yadjacent the web of the adjoining Stile of said second ladder section, a pair of Side flanges formed integral with and extending inwardly from the web of Such stile of the third ladder Sec tion, outwardly adjacent the side flanges of the adjoining stile of said second ladder section, and a rung mounting and stiffening flange formed integral with and extending inwardly from one of said fianges of such stile of the third ladder sect-ion, with the rungs of Said third ladder section being secured at their ends to the rung mounting and stiffening flanges of the Stiles of said third ladder section.

7. The combination of claim 6, further including a fourth ladder Section lhaving a pair of Ilaterally spaced Stiles and a tier of rungs extending between and interconnecting Said Stiles, with the Stiles olf Said third ladder Section being telescopically received in the 4Stiles of said fourth ladder section, each Stile of the fourth ladder Section comprising a web extending outwardly adjacent the web of the adjoining stile of said third ladder section, a pair of Side anges formed integral with and extending inwardly from the web of such Stile of the fourth ladder section, outwardly adjacent the side flanges of the adjoining Stile of Sa-id third ladder section, and a rung mounting and Stiffening flanges for-med integral with and extending 'outwardly from the side fian'ge of such stile of the fourth ladder Section that is located closest to the rung mounting and stiffening flange olf the adjoining stile of Said third ladder section, with the rungs o-f said fourth ladder section being secured at their ends to the rung mounting and stiffening flanges of the Stiles of Said fourth ladder section.

8. The combination of claim '7, further including a fifth ladder section having a pair of laterally spaced stilles an-d a tier of rungs extending between and interconnecting Said Stiles, with the Stiles o-f said fourth ladder section being telescopically received in the Stiles of Said fifth ladder section, each Said stile of the fth ladder section comprising a web extending outwardly adjacent the web Iof the adjoining Stile of Said fourth ladder section, a pair olf side anges formed integral with and extending inwardly from the web of such Stile of the fifth ladder section, outwardly adjacent the side flanges of the adjoining Stile of said fourth ladder Section, and a rung mounting and stiffening flange formed integral with and extending outwardly from the side flange of such St-ile of the fifth ladder section that is the furtherest removed from the rung mounting and stiffening fiange of said fourth ladder section, with the rungs of said fifth ladder sec-tion being Secured at their ends to the rung mounting and Stiffening flanges of the Side members of said fifth ladder Section.

9. In a telescopic ladder, first and second ladder Sections, each comprising a pair of laterally spaced Stiles and a tier of rungs extending between and interconnecting said stiles, with each of the stiles of the first ladder section comprising a web, a pair of side flanges formed integral with and turning inwardly from said web, and a r-ung mounting and stifiening llange formed integral with and extending inwardly from one of said side flanges, substantially parallel to the web of such stiles and substantially perpendicularly to the rung axes, with the rungs of said rst ladder section being secure-d at their ends to the said rung mounting and stifening flanges, and each stile of the second ladder section comprising a web extending outwardly adjacent, and substantially parallel to, the web of the adjoining stile of said first ladder section, a pair of side flanges formed with and extending inwardly from the web olf such stile of the second ladder section, outwa-rdly adjacent and substantially parallel to the side llanges of the adjoining stile of said first ladder section, and a rung mounting and stiffening llange formed integral with rand extending inwardly from the side flange of such stile of the second ladder section that is closest to the rung mounting and stilening flange of the adjacent stile of said irst ladder section, with the rungs of said second ladder section being secured at their ends to the said rung mounting and stiffening llanges of the stiles of said second ladder section.

10. A telescopic ladder according to claim 9, further including means for locking adjacent ladder sections together when extended, said means comprising an elongated relatively flat and thin spring element disposed outwardly of, and connected at one of its ends to, at least one stile of each relatively lower ladder section, and an inwardly projecting detent secured to the end of said spring element opposite from vthe connection, with an opening lfor such detent being formed in the stile to which the spring member is connected, and with a second opening being formed in the adjacent stile of the other ladder section, in the path of such detent, so that when the ladder sections are pulled relatively apart the said detent and said second opening are moved relatively together, `and the detent can enter into such opening and prevent further relative movement of the two ladder sections, said spring elements further including handle means by which it may be grasped for the purpose of pulling the detent out of engagement from said second opening, for permitting the ladder sections to be moved relative to eachother.

11. In a telescopic ladder, first 4and second ladder sections, each comprising a pair of laterally spaced stiles and a tier of rungs extending between and interconnecting said stiles, with each of the stiles of the rst ladder section comprising a web, a pair of side flanges formed integral with and turning inwardly from said web, and a rung mounting and stiffening flange formed integral with and extending inwardly lfrom `one of said side flanges, substantially parallel to the web of such stile, and substantially perpendicularly to the rung axes, with the rungs of said first ladder section being secured at their ends to the said rung mounting and stiffening llanges, and each stile of the second ladder section comprising a web extending outwardly adjacent, and substantially parallel to, the web of the adjoining stile of said first ladder section, a pair of side flanges formed with and extending inwardly from the web of such stile of the second ladder section, outwardly adjacent and `substantially parallel to the side flanges of Ithe adjoining stile of said lirst ladder section, and a rung mounting and stil-lening flange formed integral with and extending outwardly from the side llange of such stile of the second ladder section that is closest to the r-ung mounting and stiffening flange of the adjacent stile of said rst ladder section, substantially parallel to the web of said stile of the second ladder section, and substantially perpendicularly to the rung axes, with the rungs of said second ladder section being secured at their ends to the said rung mounting and stiftening flanges of the stiles of said second ladder section.

12- A telescopi? ladder according to claim 11, further including means for locking adjacent ladder sections together when extended, said means comprising an elongated, relatively tlat and thin spring element disposed outwardly of, and connected at one of its ends to, at least one stile of each relatively lower ladder section, and an inwardly projecting detent secured to the end of said spring element opposite from the connection, with an opening for such detent being formed in the stile to which the spring member is connected, and with a second opening being formed in the adjacent stile of the other ladder section, in the path of such detent, so that when the ladder sections are pulled relatively apart theA said detent and said second opening are moved relatively together, and the detent can enter into such opening and prevent further relative movement of the two ladder sections, said spring elements further including handle means by which it may be grasped for the purpose of pulling the detent out of engagement from said second opening, for permitting the ladder sections to be moved relative to each other.

13. In a telescopic ladder, first and second ladder sections, each comprising a pair of laterally spaced stiles and a tier of rungs extending between and interconnecting said stiles, with each of the stiles of the first ladder section comprising a web, a pair of side flanges formed integral with and turning inwardly from said web, and a rung lmounting and stiflening flange formed integral with and extending outwardly from one of said side flanges, and each of the stiles of the second ladder section comprising a web extending outwardly adjacent the web of the adjoining stile of said rst ladder section, a pair of side flanges formed integral with and extending inwardly from the web of such stile of the second ladder section, outwardly adjacent the side flanges of the adjoining stile of said first ladder section, such that the stiles of said first ladder section are telescopically received in the stiles of said second ladder section, and a rung mounting and stiffening flange formed with and extending outwardly from the side llange of such stile of the second ladder section that is the furtherest removed from the rung mounting and stiffening flange of the rst ladder section, with the rungs of said first ladder section being secured at their ends to the rung mounting and stiffening flanges of the stiles of said first ladder section, with the rungs of said second ladder section being secured at their ends to the said rung mounting and stiffening flanges of the stiles of said second ladder section, and with the tier of rungs of said first ladder section lbeing generally parallel to the tier of rungs of said second ladder section.

14. A telescopic ladder according to claim 13, further including means for locking adjacent ladder sections together when extended, said means comprising an elongated, relatively flat and thin spring element disposed outwardly of, and connected at one of its ends to, at least one stile of each relatively lower ladder section, and an inwardly projecting detent secured to the end of said spring element opposite from the connection, with an opening for such detent being formed in the stile to which the spring member is connected, and with a second opening being formed in the adjacent stile of the other ladder section, in the path of such detent, so that when the ladder sections are pulled relatively apart the said detent and said second opening are moved relatively together, and the detent can enter into such opening and prevent further relative movement of the .two ladder sections, said spring elements [further including handle means by which it may be grasped for the purpose of pulling the detent out of engagement from said second opening, for permitting the ladder section to be moved relative to each other.

15. A telescopic extension ladder comprising first and second ladder sections, each including a pair of laterally spa-ced stiles and a tier of rungs extending between and interconnecting said stiles, with the stiles of said second ladder section being of inwardly opening channel con- 13 iiguration, with the stiles of said tirst ladder section being telescopically received in the stiles of said second ladder section, and with the tier or rungs of said iirst ladder section being generally parallel to the tier or rungs of said second ladder section, said first ladder section being divided longitudinally into major and minor parts, and said first ladder section including means pivotally connecting said major `and minor parts together, for movement between a substantially aligned posit-ion and an angularly related position, stop means for preventing the said iirst and second ladder sections from being pulled entirely apart, said stop means -comprising a stop member on said second ladder section adjacent the -upper end of one of its side members, and a complementary stop member secured to the corresponding stile of the rst ladder section, in the minor part olf such section, such stop means permitting the major part of the irst ladder section to be pulled completely out of telescopic engagement by the second ladder section, :but preventing removal of said minor part, said pivotal connection means permitting movement of the major part of the first ladder section into an acute angular position relative to the second ladder section, and said minor ladder part still engaged thereby, and brace means interconnectable between intermediate portions of said major part of the first ladder section and said second ladder section.

16. A telescopic ladder according to claim 15, further including means for locking adjacent ladder sections together when extended, said means comprising an elongated, relatively at and thin spring element disposed outwardly of, and connected at one of its ends to, at least one stile of each yrelatively lower ladder section, and an inwardly projecting detent secured to the end of said spring element opposite from the connection, with an opening for such detent being iformed in the stile to which the spring member is connected, and with a second opening being formed in the adjacent stile of the other ladder section, in the path of such detent, so that when the ladder sections are pulled relatively apart the said detent and said second opening lare moved relatively together, and the detent can enter into such opening and prevent turther relative movement of the two ladder sections, said spring elements further including handle means by which it may be grasped for the purpose of pulling the detent out of engagement from said second opening, for permitting the ladder sections to be moved relative to each other.

17. A telescopic extension ladder comprising a plurality of ladder sections, including at least one with a section both above and below it, each of which sections includes a pair of parallel stiles of inwardly opening channel configuration, each said stile being composed of a plurality of relatively thin panel portions, including a web portion, a pair of side anige portions :formed integral with and extending inwardly from the side edges of said web portion, and a stiftening flange portion formed integral with each of said side ilange portions and extending therefrom in a spaced, substantially parallel relationship with the web portion, and a single tier of rungs extending between and interconnecting said stiles, with the web and -stiiening ilange panel portions of said stiles extending in planes which are substantially perpendicularly rel-ated to the rung axes, .and connector means connecting the ends of the rungs to one of such web and stiiening panel portions, with each tier of rungs be-ing in parallelism with each other tier of rungs, with the stiles of each relatively upper ladder section being telescopically received in the stiles of the section below it, with the s-tiles of each relatively upper ladder section having an upper portion which extends upwardly a short distance above the top ends of the Stiles of the section below it, and means for locking adjacent ladder sections together when extended, said means comprising an elongated, irelatively Hat .and thin spring element disposed outwardly of, and connected at one olf its ends to, a panel portion of at least one stile of each relatively lower ladder section, and an inwardly projecting detent secured to the end of said spring element opposite from the connection, with an opening for such detent [formed in said panel portion to which the spring member is connected, and with a second opening being formed in the adjacent panel portion of the relatively upper ladder section, in the path of such detent, `so that when the ladder sections -are pulled relatively apart the said detent and said second opening are moved relatively together, and the detent can enter into such opening and prevent further relative movement of the two ladder sections, said spring element further including handle means by which it 'may be grasped for the purpose of pulling the detent out of engagement from said second opening, for permitting the ladder sections to be again moved relative to each other, and with the spr-ing element on each section which has another section both above and below it extending across, and being secured to, the web panel of its stile, in the said upper end portion olf said stile.

18. A telescopic ladder according to claim 17, wherein each `spring element is pivotally connected to its panel portion, so that the detent can be pivotally moved out from a position of registry with the opening in said panel portion.

References Cited by the Examiner UNITED STATES PATENTS 37,470 1/11863. Willis 182-208 294,199 2/ 1884 Cloyes 1182--204 567,814 9/ 1896` Orna'towski 182-67 1,192,387 7/191'6 Cardarelli 182-67 X 2,306,453 12/ 1942 Madden 182-67 FOREIGN PATENTS 1,211,973 10/ 1959 France.

524,467 `8/1940 Great Britain.

REINALDO P. MACHADO, Primary Examiner.

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Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3502173 *Dec 9, 1968Mar 24, 1970Arnold Harold GElectrically insulated ladder
US3861500 *Sep 4, 1973Jan 21, 1975Dempsey John PLadder leveler
US6505707 *Sep 3, 1999Jan 14, 2003Hurrican Graphics, Inc.Combination tree stand, blind and equipment carrier
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Classifications
U.S. Classification182/211
International ClassificationE06C1/00, E06C1/12
Cooperative ClassificationE06C1/12
European ClassificationE06C1/12