US3866714A - Convertible ladder - Google Patents

Abstract

A convertible ladder including front and rear step sections coupled for swinging movement between generally parallel, coextensive positions and relatively inclined positions to configure the step sections as a step ladder or for generally parallel, sliding movement from co-extensive positions to extended positions to configure the step sections as an extension ladder. A support cradle is mounted on the front step section for swingably supporting the rear step section when the sections move to and from the relatively inclined positions and includes a portion which is movable between a support position underlying a portion of the rear step section when the front and rear sections are relatively extended and a removed position permitting relative movement of the step sections between the co-extensive positions and the extended positions.

Description

Elnited States Patent [191 Waldron Feb. 18, 1975 CONVERTIBLE LADDER [76] Inventor: Noel E. Waldron, Rt. No. 1, Elwell,

Mich. 48832 22 Filed: Dec. 13, 1973 21 Appl. No.: 424,189

Related US. Application Data [63] Continuation-in-part of Ser. No. 267,551, June 29,

1973, Pat. No. 3,785,455.

Primary ExaminerReinaldo P. Machado Attorney, Agent, or FirmJohn .l. Swartz [57] ABSTRACT A convertible ladder including front and rear step sections coupled for swinging movement between gener- 5 ally parallel, co-extensive positions and relatively inclined positions to configure the step sections as a step ladder or for generally parallel, sliding movement from co-extensive positions to extended positions to configure the step sections as an extension ladder. A support cradle is mounted on the front step section for swingably supporting the rear step section when the sections move to and from the relatively inclined positions and includes a portion which is movable between a support position underlying a portion of the rear step section when the front and rear sections are relatively extended and a removed position permitting relative movement of the step sections between the coextensive positions and the extended positions.

11 Claims, 14 Drawing Figures I MINI" .IITEh'Ti-bramams 3.866;"!14

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CONVERTIBLE LADDER BACKGROUND or THE INVENTION This application is a continuation-in-part of application Ser. No. 267,551, filed in the US Patent Office June 29, 1973 now US. Pat. No. 3,785,455, which is incorporated here by reference.

This invention relates to a ladder, and more particularly to a convertible ladder which can be configured as either a step ladder or an extension ladder. Accordingly, it is an object of the present invention to provide a convertible ladder which can be quickly and easily converted to a step ladder or an extension ladder.

It is another object of the present invention to provide a convertible ladder which includes ladder sections that are swingable between generally parallel coextensive positions and relatively inclined positions and apparatus which will automatically move to a locking position when the ladder sections are relatively swung between coextensive positions and relatively inclined positions to lock the step sections in the relatively inclined positions.

Yet another object of the present invention is to provide a convertible ladder including a pair of step sections coupled for generally parallel movement between coextensive and extended positions and swingable support apparatus on one of the step sections including a portion normally disposed in the path of a portion of the other step section for supporting the other step section when the sections are in the extended positions but which is automatically moved to a removed position out of the path of the portion on the other section when the sections are being moved to the extended positions.

A further object of the present invention is to provide a convertible ladder including a swingable support cradle on a front ladder section having at least a portion which is movable from a removed, inoperative position rearward of a portion of a rear ladder section to a support position underlying the portion to support the rear ladder section on the front ladder section when the sections are relatively longitudinally moved to relatively extended positions.

A still further object of the present invention is to provide a convertible step ladder of the type mentioned including a cradle and locking mechanism for locking the cradle in a position adjacent the rear ladder section to prevent the cradle from swinging rearwardly when the step sections are parallel.

Another object of the present invention is to provide a convertible ladder of the type described including a cradle, pivotally mounted on a front ladder section, which supports the rear ladder section for swing movement between positions coextensive with, and inclined to, the front ladder section while permitting generally parallel movement of the rear ladder section from the coextensive position to a generally parallel extended position in which it is supported by the cradle.

Another object of the present invention is to provide a convertible ladder of the type described including a rear ladder section supporting a cradle which is swingably mounted on a front ladder section for movement between a first position in which it holds the front and rear ladder sections in relatively inclined positions and a second position in which it prevents the ladder sections from spreading when they are in the coextensive and extended positions.

Still another object of the present invention is to provide a convertible ladder of the type described including a swingable support cradle, mounted on the front ladder section having a swingable support portion swingable therewith and relative thereto between a support position underlying a portion of the rear ladder section and a removed position in which it permits the ladder sections to be moved between the extended positions and the coextensive positions.

Still another object of the present invention is to provide a convertible ladder of the type described including an article support shelf mounted on the swingable support cradle.

Yet another object of the present invention is to provide a convertible ladder of the type described including a new type support cradle which couples the sections for relative swinging and sliding movement.

Other objects and advantages of the present invention will become apparent as the description thereof proceeds.

SUMMARY OF THE INVENTION A ladder which can be selectively converted to either an extension ladder or a step ladder comprising: front and rear ladder sections coupled for swinging movement to and from relatively inclined positions in which the ladder is configured as a step ladder and for genen ally parallel sliding movement from generally coextensive positions to extended positions in which the ladder is configured as an extension ladder; cradle mechanism is provided on the front ladder section for supporting the rear ladder section thereon, and latch mechanism on the front ladder section, coupled to the cradle mechanism, for holding the ladder sections in the relatively inclined position and in the generally coextensive positions.

The present invention may more readily be understood by reference to the accompanying drawings, in which:

FIG. 1 is a side elevational view of a ladder constructed according to the present invention, part of the side rails being broken away to illustrate more clearly the steps thereon and the position of the locking member for locking the ladder sections in the positions illustrated in FIG. 1;

FIG. 2 is a side elevational view of the ladder illustrated in FIG. 1 with the ladder sections being illustrated in adjusted, generally parallel, coextensive positions;

FIG. 3 is a side elevational view similar to FIG. 2, but illustrating the ladder sections in partially extended positions, part of a rear ladder section side rail being broken away to illustrate more clearly the support cradle supporting the steps of the rear ladder section.

FIG. 4 is a rear elevational view of the ladder in the partially extended configuration illustrated in FIG. 3, the rear ladder section being illustrated in phantom;

FIG. 5 is a rear elevational view of the rear ladder section only;

FIG. 6 is a sectional plan view of the front ladder section only, taken along the line 6-6 of FIG. 4;

FIG. 7 is a sectional end view, taken along the line 7-7 of FIG. 4 and illustrating one of the steps on the rear ladder section supported by the cradle on the front ladder section;

FIG. 8 is a top plan sectional view of the front ladder section only, taken along the line 88 of FIG. 4.

FIG. 9 is a side elevational view of a slightly different ladder construction;

FIG. 10 is a side elevational view of the ladder illustrated in FIG. 9 with the ladder sections being illustrated in adjusted, generally parallel, coextensive positions;

FIG. 11 is a rear elevational view of the ladder illustrated in FIG. 9, parts being broken away for purposes of clarity;

FIG. 12 is an enlarged sectional plan view taken on the line 12-12 of FIG. 11;

FIG. 13 is an enlarged side view taken along the line 1313 of FIG. 12; and

FIG. 14 is an enlarged, sectional view taken along the line 14-14 of FIG. 11.

DESCRIPTION OF THE PREFERRED EMBODIMENT A ladder constructed according to the present invention is generally designated 10 and includes a front step section, generally designated 12, and a rear step or prop section, generally designated 14. The front step section 12 includes a pair of laterally spaced, longitudinal side rails 16, spanned by a plurality of steps, generally designated 18. The side rails 16 include upper, generally parallel rail portions 16a and lower, downwardly diverging side rail portions 16b for a purpose to be described. The steps 18 (FIG. 1) on the from step section 12 each include a generally horizontal foot supporting section 20 having a rearward, depending terminal lip 20a and an integral, forward, depending reinforcing plate 22 which spans the rails 16 andincludes a rearwardly bent rib 22a. A trapezoidal cutout 21 (FIG. 4) is provided in the lower portion of each of the plates 22 interjacent the side rails 16 to provide additional clearance for the foot of a person climbing the ladder.

The rear ladder section 14 includes a pair of generally parallel side rails 24 spanned by a plurality of steps 26, each exhibiting a generally inverted U-shaped end cross-section (see FIG. 7) and having a horizontal foot support portion 26a and a pair of depending leg portions 26b and 26c. With the exception of the uppermost step, the steps are all longitudinally aligned and the leg portion 26c of each step is flush with the rear face 24a of the side rails 24. The uppermost step, including the leg portion 260 thereof, is set inwardly of the rear face 24a for a purpose to become apparent hereinafter.

The front and rear ladder sections 12 and 14 are coupled together for relative movement by a pair of coupling members, generally designated 28, which permit the sections 12 and 14 to be swung between the generally coextensive positions, illustrated in FIG. 2 and the relatively inclined positions, illustrated in FIG. 1. The coupling members 28 comprise a pair of vertical support plates 30 (see FIGS. 1 and 8), fixed to the upperv ends of the front section side'rails l6, pivotally mounting a pair of rear ladder section guides 32 by pins 33. The guides 32 include vertical side plates 34 and integral front and rear guide plates 35 and 36 which embrace the rear and front surfaces 24a and 24b, respectively, of the rear section side rails 24.

The vertical side plates 34 of the guides 30 are provided with a pair of upwardly opening notches 38 for receiving a pair of laterally outwardly extending support pins 40, provided at the upper ends ofthe side rails 24 on the rear ladder section 14, when the ladder sections are in the coextensive positions, illustrated in FIG.

2, and the relatively inclined positions illustrated in FIG. 1. The rear ladder section 14, which is supported on the ladder section 12 by the support pins 40, swings about the pivot pins 33 as it is moved from the position shown in FIG. 1 to the position shown in FIG. 2.

Apparatus, generally designated 42, is provided for removably locking the ladder sections 12 and 14 in the relatively inclined positions illustrated in FIG. I and comprises a pair of latch arms 44 (FIGS. I and 4), pivotally mounted on one ofthe front ladder section steps 20 by pivot pins 48 and spanned by a cross member 50. The latch arms 44 include laterally inwardly turned latching hooks 52 having terminal ends 53 which ride along the rear surfaces 24a of the rear ladder section side rails 24. Recesses 54 are provided in the rear leg 260 of one of the steps 26 and the rear surfaces 240 of the side rails 24 to receive the terminal ends 53 of the latching hooks 52. The latching hooks 52 are provided with downwardly opening notches 56 which are received on the edge portions 54a of the rear leg 260 adjacent the cutouts 54.

The ladder section latching arms 44 are mounted internally of the diverging front ladder rail portions 16b and extend externally of the rear ladder section rails 24. The latching hooks 52 ride upwardly along the rear rail surfaces 24a when the sections 12 and 14 are swung apart until the ends 53 are received in the cutouts 54 and the notches 56 are received on the upper edge portions 54a of the cutouts 54. With the latching arms 44 locked in the position illustrated in FIG. 1, the ladder sections 12 and 14 cannot be swung toward and away from each other about the pivot pins 33 and thus a very safe step ladder is provided.

When the sections 12 and 14 are to be moved from the relatively inclined positions illustrated in FIG. 1, to the coextensive positions illustrated in FIG. 2, the latching arms 44 are moved upwardly from the positions illustrated in. FIG. 1 so that the notches 56 are clear of the upper edge portions 54a of the notches 54 and the ladder sections 14 and 12 are swung together about the pivot pins 33. The latching arms 44 fall by gravity and the hook-shaped portions 53 ride along the rear rail surfaces 24a to return to the positions illustrated in FIG. 1.

The rear ladder section guide members 32 slidably receive the rear ladder section side rails 24 and permit the side rails 24 to slide vertically, when the sections 12 and 14 are in the parallel relation, to move between the coextensive positions, illustrated in FIG. 2, and the extended positions, illustrated in FIG. 3. A pair of guide plates 37 are also provided on the front ladder section side rails 16 below the guides 32 to assist in guiding the rear ladder section 14 as it is moved vertically between the position illustrated in FIG. 2 and the position illustrated in FIG. 3.

For supporting the rear ladder section 14, in the extended position illustrated in FIG. 3, a cradle, generally designated 60, is provided and includes a pair of support arms 62 pivotally connected to the front ladder section 12 by pivot pins 63 and spanned by an angle member 64 having a pair of laterally spaced apart, hook-shaped members 66 depending therefrom and defining upwardly opening pockets 68 for receiving the legs 260 of the steps 26 on the rear ladder section 14. The cradle supported hook members 66 are normally disposed in the path of the rear ladder section steps 26 and includes a lower camming surface 69 engageable by the steps 26 as the rear ladder section 14 is moved upwardly relative to the front ladder section 12 to cam the cradle 60 rearwardly, from the position illustrated in solid lines in FIG. 3, to the removed position, illustrated in chain lines in FIG. 3, and permit the ladder sections to be extended. After a step 26 moves past the hook members 66, the cradle 60 will fall by gravity into the position illustrated in FIG. 3 to be disposed in the path of the rear legs 260 of the steps 26 when the ladder section 14 is lowered. The lower edge 26d (FIG. 7) of the legs 26c on one of the steps 26 is received in the cradle pockets 68 to preclude movement of the ladder section 14 from the extended position illustrated in FIG. 3 to the coextensive positions illustrated in FIG. 2. The upper ends 66b (FIG. 7) of the terminal portions 66a of the hook-shaped member 66 terminate below the underside 64a (FIGS. 4 and 8) of the angle member 64. A gap g (FIG. 4) is provided between the hook members 66 so that an individual can manually grasp the rear leg 26c between the hook members 66 and support the lower end 26d thereof above the upper terminal ends 66a of the books 66 and lower the leg 260 into the cradle pockets 68 without pinching an individuals hands between the steps 26 and the hook members 66.

To reconfigure the ladder as illustrated in FIG. 2, the rear ladder section 14 is moved upwardly so that the lower end 26d of the leg 26c supported on the cradle 60 is above the upper ends 66a of the cradle hooks 66 and the cradle 60 is manually swung outwardly about the pivot pins 63 to the chain line position illustrated in FIG. 3, permitting the downward movement of the ladder section 14 relative to the ladder section 12.

Apparatus, generally designated 70, is provided for locking the support cradle 60 in the position illustrated in solid lines in FIG. 3, to absolutely preclude relative swinging movement of the ladder sections 12 and 14 and comprises a pair of independent locking arms 72 pivotally mounted on the front ladder section side rails 16 by pivot pins 74. The cradle locking arms 72 include downwardly opening notches or recesses 76 which are received on the upstanding portion 64b of the angle member 64 on the cradle 60, as illustrated in FIG. 7, overlying one of the steps 26.

The upper step 26 is positioned so that the rear leg 26c thereof is set inwardlyof the rear face 24a of the rear ladder section 14 out of the path of the cradle hook members 66 to preclude the depending step leg portion 260 from being received in the hook-shaped members 66 of the cradle 60 so that the free swinging movement of the cradle 60 will not be inhibited by the upper step 26.

A support platform, generally designated 78, is provided for supporting paint buckets and the like, and includes a generally horizontal support plate 80 mounted on the flange 64c of the cradle angle member 64 by a pair of support members (not shown).

THE OPERATION which is supported on the front ladder section 12 by pins 40, is swung outwardly relative to the section 12 about the pivot pin 33 to the position illustrated in FIG. 1. As the rear ladder section 14 moves outwardly relative to the ladder section 12, the latching hooks 52 of the ladder section latching arms 44 ride along the rear surface 24a of the rails 24 until the hooks 52 are received in the recesses 54 after which time the latching arms 44 may drop by gravity or be manually forced downwardly so that the notches 56 in the latching arms 44 are received on the upper ends 54a of the rear step portions 260 adjacent the recesses 54.

When it is desired to return the ladder sections to their coextensive positions, illustrated in FIG. 2, the latching arms 44 are moved upwardly so that the notches 56 therein clear the upper ends 54a of the step portion 26c and the ladder section 14 is swung about the pivot pins 33 until the sections 12 and 14 are generally parallel as viewed in FIG. 2. The latching arms 44 will automatically drop under their own weight to the positions illustrated in FIG. 2.

If the ladder is to be configured as an extension ladder, the rear ladder section 14 is moved upwardly and the steps 26 engage the cam surface 69 on the underside of the cradle'hooks 66 to cam them rearwardly to the removed position illustrated in chain lines in FIG. 3. As soon as the second uppermost step 26 has cleared the upper ends 660 of the cradle hooks 66, the cradle 60 will swing downwardly to the solid line position illustrated in FIG. 3, underlying the leg 26c of the second uppermost step 26. The rear ladder section 14 is then slightly lowered so that the rear leg 26c of the second uppermost step 26 is received in the recesses or pockets 68 on the hooks 66. The cradle locking members 72 are then swung from the inoperative positions illustrated in FIG. 1, to the cradle locking positions illustrated in FIG. 3, so that the notches 76 receive the flange portion 64b of the cradle angle member 64. The ladder then may be positioned against a wall or the like so that the upper ends ofthe side rails 40 are positioned against the wall. The ladder can, of course, be extended to a plurality of different heights and the cradle used to support any of the steps 26 with the exception of the uppermost step.

When the ladder is to be returned to the coextensive configuration illustrated in FIG. 2, the cradle locking hooks 72 are swung to the inoperative position illustrated in FIG. '1, the ladder section 14 is moved upwardly slightly so that the lower end 26d of the step leg 26c received in the cradle pockets 68 is positioned above the upper ends 660 of the cradle hooks 66, and the support cradle 60 is swung to the chain line position illustrated in FIG. 3. The rear ladder section 14 is lowered to the position illustrated in FIG. 2 so that the rear ladder section 14 is supported by the pins 40 on the front ladder section 12. The cradle locking hooks 72 are then swung from the positions illustrated in FIG. 1 to the positions illustrated in FIG. 3 and the ladder may again be stored.

DESCRIPTION OF AN ALTERNATE EMBODIMENT A slightly modified ladder construction, generally designated and illustrated in FIGS. 9 14, includes spaced, longitudinal side rails 116, spanned by a plurality of steps, generally designated 118. To laterally stabilize the ladder, the lower end portions 116a of the side rails 116 downwardly diverge and mount angularly shaped, braces 117 (FIG. 11) having ground engaging rubber pads 117a.

The rear ladder section 114 includes a pair of generally parallel side rails 124 spanned by a plurality of steps 126, each exhibiting a generally inverted U- shaped end cross-section (see FIG. 9) and having a horizontal foot support portion 126a and a pair of depending front and rear leg portions l26b and 126C. The steps 126 are all longitudinally aligned with the rear leg portion l'26c of each step 126 being flush with the rear face 124a of the side rails 124 and the other leg portion 126b of each step 126 being slightly inset from the front face 124b.

The front and rear ladder sections 112 and 114 are coupled together by a pair of coupling members, generally designated 128, which permit the ladder sections 112 and 114 to be swung between the generally coextensive positions, illustrated in FIG. 10, and the relatively inclined positions, illustrated in FIG. 9. The coupling members 128 comprise a pair of generally vertical side plates 130, fixed to the upper ends of the front section side rails 116, mounting a pair of rear ladder section guides 132 and 133. The guides 132 and 133 embrace the rear and front surfaces 124a and 124b, respectively, of the rear ladder section side rails 124.

When the ladder sections 112 and 114 are relatively swung to the inclined positions illustrated in FIG. 9, the upper edge portions 134 ofthe rear ladder section rails 124 bear against the rear edge portion 138a of the uppermost step 138 on the front section 116.

When the ladder sections 112 and 114 are in either the inclined positions illustrated in FIG. 9, or the generally parallel positions, illustrated in FIG. 10, the rear ladder section 114 is supported on the front ladder section 112 by a cradle assembly, generally designated 160, including a pair of laterally spaced support arms 162 pivotally mounted on the front ladder section side rails 116 by pivot pins 163. An angle member 164 spans the support arms 162 and includes a rectangular, centrally located cutout 165 receiving a ladder support hook, generally designated 166, which is pivotally mounted on the angle member 164 via pivot pins 167. The support hook 166 includes an upstanding flange 168 which is receivable behind the rear leg 1266' on the uppermost step of the rear ladder step section when the hook 166 is in the position illustrated in FIG. 14. A pair of stops 170 is provided on the angle member 164 to support the hook 166 in the position illustrated in FIG. 14. The rear ladder section 114 is thus supported by the cradle 160 for swinging movement between the positions illustrated in FIGS. 9 and about the pivot pins 163 on the front ladder section 112.

Apparatus, generally designated 142, is provided for removably locking the ladder sections 112 and 114 in the relatively inclined positions illustrated in FIG. 9, as well as the generally parallel positions illustrated in FIG. 11 and comprises a pair of L-shaped latches 144 each having a relatively short leg 144a pivotally mounted on one of the front ladder section side rails 116 for swinging movement in a vertical plane by pivot pins 148 and spanned by a cross member 150. Each latch 144 includes a relatively longer leg section 144b which is at right angles to a leg 144a and rides on a lat- 8 erally projecting latching pin 152 fixed to the cradle 160. Notches 153 and 154 are provided on the legs 144a and 144b respectively for receiving the pins 152 when the ladder sections 112 and 114 are in the closed and spread positions illustrated in FIGS. 10 and 9 respectively. The notches 153 are located at the junction of the legs 144a and 1441; so that if the latches 144 are inadvertently swung upwardly from the positions illustrated in .FIG. 10 and the pins 152 are inadvertently displaced from the notches 153, the pins 152 will bear against the legs 144b and continue to hold the ladder sections 112 and 114 in the generally parallel positions.

The ladder section latches 144 are mounted externally of the front ladder rails 116 and extend externally of the rear ladder section rails 124. After the latches 144 are partially swung from the positions illustrated in FIG. 10, the ladder sections 112 and 114 are free to be swung apart and the latches 144 will ride upwardly along the rear rail surfaces 124a until the pins 152 are received in the cutouts or notches 154. With the latches 144 locked in the positions illustrated in FIG. 9, the ladder sections 112 and 114 cannot be swung toward and away from each other about the pivot pins 163 and thus a very safe step ladder is provided.

When the sections 112 and 114 are to be relatively swung from the relatively inclined positions illustrated in FIG. 9, to the coextensive positions illustrated in FIG. 10, the latches 144 are moved upwardly from the positions illustrated in FIG. 9 so that the notches 154 are clear of the pins 152. This permits the rear ladder section 114 and the cradle to be swung together about the pivot pins 163 toward the front ladder section 112. The latches 144 fall by gravity and ride along the rear rail surfaces 1240 to return to the latching positions illustrated in FIG. 10 in which the notches 153 receive the cradle mounted pins 152.

The rear ladder section guide members 132 and 133 slidably receive the rear ladder section side rails 124 and permit the side rails 124 to slide vertically, when the sections 112 and 114 are in the parallel relation, to move between the coextensive positions, illustrated in FIG. 10, and the extended positions, illustrated in chain lines in FIG. 11. The cradle bracket 164, positioned behind the ladder section 114, also guides the rear ladder section 114 as it is moved vertically between the coextensive position illustrated in solid lines in FIG. 11 and the extended position illustrated in chain lines in FIG. 11.

The hook flange 168, which is normally disposed in the path of the legs 1260 on the rear ladder section steps 126, includes a lower camming surface ,169 engageable by the upper positions of the steps 126 as the rear ladder section 114 is moved upwardly relative to the front ladder section 112 to cam the support hook 166 rearwardly, from the position illustrated in solid lines in FIG. 14, to the removed position, illustrated in chain lines in FIG. 14, and permit the ladder sections 112 and 114 to be extended. After a step 126 moves upwardly past the hook 166, the hook 166 will fall by gravity to the position illustrated in FIG. 14 to be disposed in the path of the rear step leg 1266 when the ladder section 114 is lowered. The lower edge 126d (FIG. 14, of the leg 1260 is received outwardly of the cradle flange 168 to preclude movement of the ladder section 114 from the extended position, illustrated in chain lines in FIG. 11, to the coextensive positions illustrated in FIG. 10.

To reconfigure the ladder as illustrated in solid lines in FIG. 10, the rear ladder section 114 is moved upwardly so that the lower end 126d of the leg 126a supported on the cradle 160 is abovethe upper ends l68b of the cradle hook flange 168 and the cradle hook 166 is manually swung upwardly about the pivot pins 167 to the chain line position illustrated in FIG. 14 permitting the downward movement of the ladder section 114 relative to the ladder section 112.

When the ladder sections 112 and 114 are positioned as illustrated in FIG. 14, the rear leg 1266 of the uppermost step 126 is received by the cradle hook member 166 to be supported thereby for free swinging movement with the cradle 160.

A support platform, generally designated 178, is provided for supporting paint buckets and the like, and includes a generally horizontal support plate or shelf 180 pivotally mounted on the cradle angle member 164 by a pair of bolts 182.

THE OPERATION The ladder will normally be stored in the configuration illustrated in FIG. wherein the front and rear ladder sections 112 and 114 are generally coextensive with each other. If the ladder is to be used as a step ladder, the latches 144 are swung from the positions illustrated in FIG. 10 to the positions illustrated in FIG. 9, to release the cradle 160 for free swinging movement. The rear ladder sections 114, which is supported on the front ladder section 112 by the cradle 160 is swung outwardly relative to the ladder section 112 about the pivot pin 163 to the position illustrated in FIG. 9. As the rear ladder section 114 moves outwardly relative to the ladder section 112, the latching hooks 144 ride along the rear surface 124a of the rails 124 until the locking pins 152 are received in the recesses 154. The latching arms 144 may drop by gravity or be manually forced downwardly to insure mating of the notches 124 and pins 152. This locks the cradle 160 in the inclined position illustrated in FIG. 9 and, since the rear ladder section is supported by the cradle, also locks the rear ladder section in the inclined position.

When it is desired to return the ladder sections 112 and 114 to their coextensive positions, illustrated in FIG. 10, the latches 144 are moved upwardly so that the notches 154 clear the cradle mounted latching pins 152. The ladder section 114 and cradle 160, are swung about the pivot pins 163 until the ladder sections 112 and 114 are generally parallel as viewed in FIG. 10. The latches 144 will automatically drop under their own weight to the latching positions illustrated in FIG. 10 in which the pins 152 are received by the notches 153. This locks the cradle 160 in the position illustrated in FIG. 10 and prevents the ladder sections from spreading.

If the ladder is to be configured as an extension ladder, the rear ladder section 114 is moved upwardly and the upper portion of the steps 126 on the rear ladder section engage the cam surface 169 on the underside of the cradle hook 166 to cam it rearwardly to the removed position illustrated in chain lines in FIG. 14. When each of the rear ladder section steps 126 has cleared the upper ends 1681: of the cradle hook flange 168, the cradle 160 will swing downwardly to the solid line position illustrated in FIG. 11, underlying the leg 1266 of the second uppermost step 126. The rear ladder section 114 is then slightly lowered so that the rear leg 126c of one of the rear ladder section steps 126 is supported by the hook 166. The latches 144 remain in the positions illustrated in FIG. 10 to hold the cradle in the position illustrated in FIG. 10. The ladder then may be positioned against a wall or the like so that the upper ends of the side rails 124 are positioned against the wall. The ladder can, of course, be extended to a plurality of different heights and the cradle 160 used to support any of the steps 126.

When the ladder is to be returned to the coextensive configuration illustrated in FIG. 10, the rear ladder section 114 is moved upwardly slightly so that the lower end 1260' of the step leg 1260 which is received in the cradle pockets 168, is positioned above the upper ends l68b of the cradle hook 166, and the support cradle hook 166 is swung to the chain line position illustrated in FIG. 14. The rear ladder section 114 is then lowered to the position illustrated in FIG. 10 and the cradle hook 166 is returned to its support position so that the uppermost rear step 126 of the rear ladder section 114 is supported by the cradle 160 supported by the front ladder section 112.

It is to be understood that the drawings and descriptive matterare in all cases to be interpreted as merely illustrative ofthe principles of the invention rather than as limiting the same in any way, since it is contemplated that various changes may be made in various elements to achieve like results without departing'from the spirit of the invention or the scope of the appended claims.

What is claimed is:

1. A ladder which can be selectively converted to either an extension ladder or a step ladder comprising:

front and rear ladder longitudinally extending sections each including a plurality of longitudinally spaced steps;

coupling means mounting said rear ladder section on the rear face of said front ladder section for either swinging movement between a position, generally parallel to and coextensive with said front ladder section, and a position inclined to said front ladder section in which said ladder is configured as a step ladder, or generally parallel, longitudinal, relative sliding movement between said coextensive position and an extended position, generally parallel to said front ladder section, in which said ladder is configured as an extension ladder including: rear ladder section support means having at least a portion mounted on said front ladder section for movement with the rear ladder section when said rear section moves between said coextensive position and said inclined position, said portion being movable between a position permitting said rear section to be moved from said extended position to said coextensive position, and a support position underlying a portion of said rear ladder section to preclude relative movement of said rear ladder section from said extended position to said coextensive position; and

latch means mounted on said front ladder section for movement between a first position in which it holds said rear section in said inclined position and a second position in which it prevents said support means and said rear ladder section from moving away from said front section when said rear ladder section is in either said coextensive position or said extended position.

2. The ladder as set forth in claim 1 including support shelf means mounted on said support means for movement therewith and for swinging movement relative thereto.

3. The ladder as set forth in claim 1 wherein said latch means is mounted on said front ladder section for swinging movement between a raised position, in which it locks said rear section in said inclined position and a lowered position, in which said latch means locks said rear ladder section in said generally parallel positions, said latch means being movable between said lowered and raised positions in response to movement of said rear ladder section between said inclined position and said coextensive position.

4. The ladder as set forth in claim 1 wherein said front and rear ladder sections each include a pair of laterally spaced apart rails spanned by said steps; said latch means comprises a pair of L-shaped members each including one leg pivotally mounted on one of the laterally spaced rails of said front ladder section for swinging movement in a vertical plane and another leg fixed thereto, a cross member spanning said other leg, each of said legs including a notch therein, latching pins provided on laterally opposite sides of said support means, receivable in said notches when said rear ladder section is in either of said inclined or parallel positions.

5. The ladder as set forth in claim 4 wherein the notch in said one leg of each L-shaped member is at the junction of said legs.

6. A ladder which can be selectively converted to either an extension ladder or a step ladder comprising:

front and rear longitudinally extending ladder sections each including a plurality of longitudinally spaced steps;

coupling means releasably mounting said rear ladder section on the rear face of said front ladder section for either relative swinging movement between a coextensive position, generally parallel to said front ladder section, and a position inclined to said front ladder section in which said ladder is configured as a step ladder, or generally parallel, longitudinal relative sliding movement between said coextensive position and an extended position, generally parallel to said front ladder section in which said ladder is configured as an extension ladder including: rear ladder section support means, mounted on said front ladder section for movement with said rear ladder section as said rear ladder section moves to and from said inclined position, including a support portion mounted thereon for movement therewith and for movement relative thereto between a support position underlying a portion of said rear ladder section to preclude relative movement of said rear ladder section from said extended position to said coextensive position; and

latch means movable to and from a position in which it prevents said support portion from moving from said support position and prevents said ladder sections from spreading. 7. The ladder as set forth in claim 6 wherein said support means is swingably mounted on said front ladder section and said support portion is swingably mounted thereon.

8. The ladder as set forth in claim 6 wherein guide means is mounted on said front section for vertically guiding said rear section as it moves on said front section between said coextensive position and said extended position but permitting said rear section to swing on said front section from said coextensive position to said inclined position.

9. The ladder as set forth in claim 8 wherein said guide means comprises front and rear guide members on said front ladder section received on front and rear sides respectively of said rear ladder section.

10. A ladder which can be selectively converted to either an extension ladder or a step ladder comprising: front and rear, longitudinally extending, ladder sec tions each including a plurality of longitudinally spaced steps;

cradle means, pivotally mounted on said front ladder section, supporting said rear ladder section for swinging movement between a position in which it is generally coextensive with and parallel to said front ladder section and a position in which it is inclined to said front ladder section so that said ladder is configured as a step ladder;

said cradle means mounting a support portion movable between a support position in which it underlies a portion of said rear ladder section when said rear ladder section is in said inclined position and 7 said generally parallel positions and a removed position in which said rear ladder section can move between said coextensive position and an extended position in which it remains parallel to said front section, said support portion being selectively movable to said support position underlying another portion of said rear ladder section to support said rear ladder section on said front ladder section when said rear ladder section is in said extended position and said removed position permitting said rear ladder section to return to said coextensive position.

11. The ladder as set forth in claim 10 wherein the lower end portions of said front ladder section downwardly diverge, and downwardly diverging brace members are fixed to said lower end positions to increase lateral stability.

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Claims (11)

1. A ladder which can be selectively converted to either an extension ladder or a step ladder comprising: front and rear ladder longitudinally extending sections each including a plurality of longitudinally spaced steps; coupling means mounting said rear ladder section on the rear face of said front ladder section for either swinging movement between a position, generally parallel to and coextensive with said front ladder section, and a position inclined to said front ladder section in which said ladder is configured as a step ladder, or generally parallel, longitudinal, relative sliding movement between said coextensive position and an extended position, generally parallel to said front ladder section, in which said ladder is configured as an extension ladder including: rear ladder section support means having at least a portion mounted on said front ladder section for movement with the rear ladder section when said rear section moves between said coextensive position and said inclined position, said portion being movable between a position permitting said rear section to be moved from said extended position to said coextensive position, and a support position underlying a portion of said rear ladder section to preclude relative movement of said rear ladder section from said extended position to said coextensive position; and latch means mounted on said front ladder section for movement between a first position in which it holds said rear section in said inclined position and a second position in which it prevents said support means and said rear ladder sectiOn from moving away from said front section when said rear ladder section is in either said coextensive position or said extended position.

2. The ladder as set forth in claim 1 including support shelf means mounted on said support means for movement therewith and for swinging movement relative thereto.

3. The ladder as set forth in claim 1 wherein said latch means is mounted on said front ladder section for swinging movement between a raised position, in which it locks said rear section in said inclined position and a lowered position, in which said latch means locks said rear ladder section in said generally parallel positions, said latch means being movable between said lowered and raised positions in response to movement of said rear ladder section between said inclined position and said coextensive position.

4. The ladder as set forth in claim 1 wherein said front and rear ladder sections each include a pair of laterally spaced apart rails spanned by said steps; said latch means comprises a pair of L-shaped members each including one leg pivotally mounted on one of the laterally spaced rails of said front ladder section for swinging movement in a vertical plane and another leg fixed thereto, a cross member spanning said other leg, each of said legs including a notch therein, latching pins provided on laterally opposite sides of said support means, receivable in said notches when said rear ladder section is in either of said inclined or parallel positions.

5. The ladder as set forth in claim 4 wherein the notch in said one leg of each L-shaped member is at the junction of said legs.

6. A ladder which can be selectively converted to either an extension ladder or a step ladder comprising: front and rear longitudinally extending ladder sections each including a plurality of longitudinally spaced steps; coupling means releasably mounting said rear ladder section on the rear face of said front ladder section for either relative swinging movement between a coextensive position, generally parallel to said front ladder section, and a position inclined to said front ladder section in which said ladder is configured as a step ladder, or generally parallel, longitudinal relative sliding movement between said coextensive position and an extended position, generally parallel to said front ladder section in which said ladder is configured as an extension ladder including: rear ladder section support means, mounted on said front ladder section for movement with said rear ladder section as said rear ladder section moves to and from said inclined position, including a support portion mounted thereon for movement therewith and for movement relative thereto between a support position underlying a portion of said rear ladder section to preclude relative movement of said rear ladder section from said extended position to said coextensive position; and latch means movable to and from a position in which it prevents said support portion from moving from said support position and prevents said ladder sections from spreading.

7. The ladder as set forth in claim 6 wherein said support means is swingably mounted on said front ladder section and said support portion is swingably mounted thereon.

8. The ladder as set forth in claim 6 wherein guide means is mounted on said front section for vertically guiding said rear section as it moves on said front section between said coextensive position and said extended position but permitting said rear section to swing on said front section from said coextensive position to said inclined position.

9. The ladder as set forth in claim 8 wherein said guide means comprises front and rear guide members on said front ladder section received on front and rear sides respectively of said rear ladder section.

10. A ladder which can be selectively converted to either an extension ladder or a step ladder comprising: front and rear, longitudinally extending, ladder sections each including a plurality of longitudinally spacEd steps; cradle means, pivotally mounted on said front ladder section, supporting said rear ladder section for swinging movement between a position in which it is generally coextensive with and parallel to said front ladder section and a position in which it is inclined to said front ladder section so that said ladder is configured as a step ladder; said cradle means mounting a support portion movable between a support position in which it underlies a portion of said rear ladder section when said rear ladder section is in said inclined position and said generally parallel positions and a removed position in which said rear ladder section can move between said coextensive position and an extended position in which it remains parallel to said front section, said support portion being selectively movable to said support position underlying another portion of said rear ladder section to support said rear ladder section on said front ladder section when said rear ladder section is in said extended position and said removed position permitting said rear ladder section to return to said coextensive position.

11. The ladder as set forth in claim 10 wherein the lower end portions of said front ladder section downwardly diverge, and downwardly diverging brace members are fixed to said lower end positions to increase lateral stability.

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