Freestanding ladders have been provided for bridging the side walls of above-ground swimming pools.

For ease of manufacture and shipment, these ladders are formed of several parts which are assembled by the customer. Typically, such ladders have inclined legs which are attached to a raised platform for support thereof. An example of such a ladder is disclosed in U. S. Patent No. 4,023,647 to Raymond C. Confer. This ladder is formed of blow-molded parts, and the steps are molded integrally with the legs. The lower end portions of the legs are engaged to base members.

Legs have been attached to upper handrails of ladders by various means such as telescoping attachments of the legs thereto. Such attachments are points of weakness, and it is considered desirable to provide ladders of several parts which, when assembled, are more sturdy.

It is accordingly an object of the present invention to provide parts which, when assembled, form a sturdier freestanding ladder or other structure.

It is another object of the present invention to provide the parts to the customer so that the parts are easily and foolproof assembled with a minimum of screws or bolts or other connectors required.

It is a further object of the present invention to minimize the number of different parts which must be manufactured for such a ladder or other structure.

It is yet another object of the present invention to provide the parts compactly for shipping.

It is a further object of the present invention to provide adjustable height to the ladder so that one ladder will fit various wall heights so that it is

unnecessary to manufacture more than one size of the ladder for a range of wall heights.

In order to provide such a structure, in accordance with the present invention, two pairs of rails are provided, each rail having an upper end portion and an intermediate portion. The end portions of each pair of rails are interlocked together, and the intermediate portions of each pair of rails are interlocked together.

A platform or other reinforcing member has a pair of means on each of its side edges for interlocking with the intermediate portions of a respective pair of rails respectively.

The above and other objects, features, and advantages of the present invention will be apparent in the following detailed description of the preferred embodiments thereof when read in conjunction with the accompanying drawings wherein the same reference numerals denote the same or similar parts throughout the several views.

Brief Description of the Drawings Fig. 1 is a perspective view of a freestanding ladder which embodies the present invention.

Fig. 2 is a side elevation view of an upper portion of a rail therefor.

Fig. 3 is a view similar to that of Fig. 2 of the upper portions of a pair of the rails therefor and illustrating joining of the rails.

Fig. 4 is a view similar to that of Fig. 2 illustrating the rails joined.

Fig. 5 is a view taken along lines 5-5 of Fig. 4, with one of the rails shown in phantom lines.

Fig. 6 is a sectional view taken along lines 6-6 of Fig. 4.

Fig. 7 is a side view of another portion of a rail and illustrating a step being attached thereto.

Fig. 8 is a sectional view taken along lines 8-8 of Fig. 7.

Fig. 9 is a view taken along lines 9-9 of Fig. 7.

Fig. 10 is a view similar to that of Fig. 7 illustrating the step attached to the rail.

Fig. 11 is a sectional view taken along lines 11-11 of Fig. 10.

Fig. 12 is a side view of a portion of a rail and illustrating a structure to which some of the steps are attached being swung upwardly to a raised position so that the steps are removed from the corresponding pair of rails.

Fig. 13 is an enlarged partial view similar to that of Fig. 12 illustrating the structure in the raised position and being locked in the raised position.

Fig. 14 is an enlarged partial view similar to that of Fig. 12 illustrating the structure in the raised locked position.

Fig. 15 is a sectional view taken along lines 15-15 of Fig. 14.

Fig. 16 is a partial view similar to that of Fig. 12 illustrating the structure being lowered into a lowered position with a step thereof being interlocked to the corresponding pair of rails.

Fig. 17 is a view taken along lines 17-17 of Fig.

16.

Fig. 18 is a sectional view taken along lines 18-18 of Fig. 17.

Fig. 19 is a side elevation view of the lower portion of a rail.

Detailed Description of the Preferred Embodiments Referring to Fig. 1, there is shown generally at 20 a freestanding ladder which may be used, for example, for bridging a circular above-ground swimming pool wall for entrance thereto and exit therefrom, such as

illustrated in the aforesaid U. S. Patent No. 4,023,647, which is hereby incorporated herein by reference. While the present invention as described herein is applied to ladders, it should be understood that the invention can be applied to other structures such as, for example, playhouses and modular walls of sheds and the like.

Thus, the present invention is not limited to an application to ladders.

The ladder 20 includes a platform 22 which will generally be positioned over the pool wall when the ladder is positioned to bridge the wall. The ladder 20 also includes an inside stairway 24 to be located inside the wall and an outside stairway 26 to be located outside the wall, the stairways 24 and 26 supporting and attached to the platform 22, as hereinafter described.

Each of the stairways 24 and 26 extends at an angle, illustrated at 38, relative to the ground or horizontal, when the ladder is standing in normal position, of, for example, about 15 degrees. The ladder 20 may also be described as having a left side and a right side, illustrated at 28 and 30 respectively, as viewed in Fig.

1.

The ladder is made of parts which may be assembled by the customer and which may be hollow parts composed of polyethylene or other suitable material constructed by blow-molding. Blow-molding is a process conventionally known in the art and is described in the aforesaid U. S. Patent No. 4,023,647 as well as in U. S.

Patent Nos. 5,244,291 to Raymond C. Confer and 4,067,614 to Confer et al, all of which patents are incorporated herein by reference. All of the parts described herein are made by blowmolding processes conventionally known to those of ordinary skill in the art to which this invention pertains, and, therefore, the processes for their manufacture will generally not be further described herein.

The ladder 20 is comprised of four rails 32, i. e., a pair of left-side rails 32L and a pair of right-side rails 32R. The inside stairway 24 comprises one of the left-side rails 32L and one of the right-side rails 32R.

Likewise, The outside stairway 26 comprises one of the left-side rails 32L and one of the rightside rails 32R.

All of the rails 32 are identical so that the total number of different parts which must be produced for the ladder may advantageously be reduced and so that the process of assembly by the customer may be easier. A plurality of steps 34 connect the rails 32 for each stairway. These steps 34 also are identical to also reduce the total number of different parts which must be produced for the ladder and to make the process of assembly by the customer easier.

Each of the rails 32 has an elongate portion 42 having a length of, for example, about 78 inches.

Unless otherwise stated, dimensions specified herein are for illustrative purposes (of the preferred embodiment) only and not for purposes of limitation. Each rail 32 has an upper end portion 36 which extends horizontally (parallel to the ground when the ladder is standing in normal position) for a short distance inwardly (toward the other of the respective pair of rails) from the elongate portion 42 of, for example, about 3 inches to connect with an identical upper end portion on the other of the respective pair of rails, i. e., the end portions 36 of rails 32L are connected together, and the end portions 36 of rails 32R are connected together, as hereinafter described. Each rail 32 also has a portion 40 intermediate its length which also extends horizontally inwardly from the elongate portion 42 over a greater distance of, for example, about 7 inches to connect with an identical intermediate portion 40 on the other of the respective pair of rails, i. e., the intermediate portions 40 of rails 32L are connected

together, and the intermediate portions 40 of rails 32R are connected together, as hereinafter described. The distance between the end and intermediate portions 36 and 40 on each rail 32 may, for example, be about 16 inches. Between the end and intermediate portions 36 and 40, each rail 32 is generally square in cross-section, having, for example, a height, illustrated at 58 in Figs. 1 and 2, of about 1 3/4 inch and a width, illustrated at 60 in Fig. 5, of about 1 3/4 inch. Below the intermediate portion 40, each rail 32 has an increased height, illustrated at 44 in Fig. 1, of, for example, about 3 1/2 inches. Each intermediate portion extends over a height, illustrated at 94 in Figs. 2 and 3, of, for example, about 5 3/8 inches.

In order to provide a sturdy and secure attachment of each pair of rails 32 together, in accordance with the present invention, the end portions 36 and the intermediate portions 40 for-each rail pair are connected together in tandem, each in an interlocking arrangement as follows.

Referring to Fig. 5, each end portion 36 has a reduced width, illustrated at 46, over substantially its length from its terminal end 52, this reduced width defining an off-set planar surface, illustrated at 48.

One of the end portions in Fig. 5 is shown in phantom lines to illustrate its fit with the other end portion, the discussion herein being with reference to the other end portion. A cut-out, illustrated at 50, is provided in and completely across the surface 48 and is spaced from the terminal end 52 thereby defining a projecting portion 68 between the cutout 50 and the terminal end 52. The depth of the cut-out 50 is such as to provide a reduced width portion 54 whose width, illustrated at 56, is substantially equal to the difference, illustrated at 62, between width 60 and reduced width 46. The cut-out 50 has a width, illustrated at 64, at its top (even with

surface 48) and tapers to an increased width, illustrated at 66, at its bottom. In order to remove the molded rail having such a taper from the mold, an insert is used. The insert, placed into the mold cavity before the molding process initiates, occupies the space indicated at 65. After the molding process, a device, i. e., a pneumatic cylinder, moves the insert from the molding cavity so when the product is removed from the mold cavity the insert does not tear the interlocking apparatus (cut-out 50 and projecting portion 68) of the present invention. The cut-out 50 is sized and shaped so that its size and shape is the same as that of the projecting portion 68, i. e., distances 66 and 70 are equal, and distances 64 and 72 are equal, whereby the projecting portion 68 of one rail 32 will fit tightly within the cut-out 50 of another rail 32 for a sturdy attachment thereof, and the taper to the cut-out 50 prevents the rails 32 from coming apart width-wise, i. e., in the direction illustrated at 74 as well as in the direction illustrated at 76. Further, since the distance 56 is substantially equal to distance 62, the overall width at the connection will be substantially equal to rail width 60 so that the surfaces of the connected rails 32 are substantially flush, as seen in Figs. 5 and 6, with each other for a pleasing appearance. For example, distances 56 and 62 may each be equal to about 1/2 inch, distances 64 and 72 may each be equal to about 7/8 inch, and distances 66 and 70 may each be equal to about 1 1/8 inch.

Referring to Fig. 6, each rail 32 has a button or semispherical nub portion 76 on its surface 48 and a similarly shaped and sized indent 78 on the bottom surface of the cut-out 50. The indent 78 is spaced a distance, illustrated at 80, from the inner surface 86 (opposite the tapered surface) of the cut-out 50 which is equal to the distance, illustrated at 82, which the

button 76 is spaced from the terminal end of the end portion 36, and both the indent 78 and the button 76 are aligned width-wise, i. e., each is spaced an equal distance from the bottom surface, illustrated at 84 in Figs. 2 and 4, of the end portion 36. For example, the button 76 and indent 78 may each be located mid-way width-wise of rail width 58, distances 80 and 82 may each be about 1/4 inch, and the diameter of each of the button 76 and indent 78 may be about 3/16 inch. This positioning will cause the indent 78 to lockingly receive the button 76 for an even tighter fit when the bottom surfaces 84 as well as the upper surfaces of the end portions 36 are flush with each other, as seen in Fig. 4, for a pleasing appearance. It should be understood that the locations of the button 76 and indent 78 may alternatively be interchanged with each other.

Referring to Figs. 2 and 3, each of the intermediate portions 40 has an outer or terminal portion 88 having a similar interlocking arrangement as provided by end portions 36. For example, each terminal portion 88 has a tapered cut-out 90 defining a similarly sized and shaped projecting portion 92.

Alternatively, each portion 88 has a button 94 and indent 96 sized and positioned to matingly receive the button 94. These elements are similar in both shape and size to the corresponding cut-out 50, projecting portion 68, button 76, and indent 78 respectively for each end portion 36, except that, the width 94 of intermediate portion 40 is greater, the widths of each of the cut-out 90 and projecting portion will also be greater, i. e., equal to width 94, as seen in Fig. 2. The grooves 50 and 90 for each rail are positioned in alignment with each other, i. e., a straight line, illustrated at 51 in Fig. 2, that is the centerline of grooves 50 and 90.

The centerline 51 is substantially vertical in

orientation when the ladder is erected and in normal position for use. Likewise, the projecting portions 68 and 92 for each rail are in alignment with each other.

Referring to Fig. 3, each pair of rails such as rails 32R are attached together by simultaneously and in tandem sliding each projecting portion 68 and 92 of each rail into the corresponding tapered cut-out 50 and 90 respectively of the other rail until each button 76 and 94 is lockingly received in the corresponding indent 78 and 96 respectively. Thus, for the end portions 36, the projecting portion 68 of a first rail is slidingly received in the cut-out 50 of a second rail of a pair, as illustrated at 98 in Fig. 3, simultaneously with the projecting portion 68 of the second rail being slidingly received in the cut-out 50 of the first rail. Similarly and simultaneously and in tandem therewith, as illustrated by a second arrow 98 in Fig. 3, for the intermediate portions 40, the projecting portion 92 of the first rail is slidingly received in the cut-out 90 of a second rail of a pair simultaneously with the projecting portion 92 of the second rail being slidingly received in the cut-out 90 of the first rail. Each thusly attached pair of rails 32 is then sturdily attached to the platform 22, as discussed hereinafter, so as to prevent the attached rails 32 from slidably disengaging from each other.

Each of the intermediate portions 40 has, at a location inwardly of the cut-out 90 and adjacent the longitudinal portion 42 of the rail, a generally rectangular cavity, illustrated at 100, extending there through. For example, the distance between the cut-out 90 and the cavity 100 may be about 2 1/4 inches, and the cavity 100 may be spaced from the bottom of portion 40 a distance of about 5/8 inch. Each cavity 100 may, for example, have a width, illustrated at 102, of about 1 3/4 inch and a height, illustrated at 104, of about 1

1/8 inch. A projecting portion 106 extends across the width 102 from the upper wall of the cavity 100 approximately mid-way (or otherwise intermediate) the length thereof. The projecting portion 106 is generally rectangular in cross-section or otherwise suitably shaped. The projecting portion 106 may, for example, be 5/8 inch lengthwise of the cavity and project into the cavity a distance, illustrated at 108, of about 1/4 inch.

The platform 22 is a flat member having a thickness which is equal substantially to the difference between distances 104 and 108 and has a pair of spaced bosses 110 which project from each of opposing side edges thereof and which are received in the cavities 100 respectively. Thus, for one side edge of the platform 22, one of the pair of bosses 110 is received in the cavity 100 for one of the pair of rails 32R, and the other of the pair of bosses 110 is received in the cavity 100 for the other of the pair of rails 32R.

Likewise, for the other side edge of the platform 22, one of the pair of bosses 110 is received in the cavity 100 for one of the pair of rails 32L, and the other of the pair of bosses 110 is received in the cavity 100 for the other of the pair of rails 32L. The upper surface of each boss 110 has a groove (not shown) therein which receives the corresponding projecting portion 106 so that the upper surface of the boss 110 engages the upper wall of the cavity 100, thereby leaving a space between the lower surface of the boss 110 and the lower wall of the cavity 100. A spacer 112 is inserted tightly into this space so that the projecting portion 106 is retained within the boss groove whereby to lockingly prevent the boss 110 from coming out of the cavity 100.

A groove, illustrated at 114, is provided in the outer side surface of each portion 40 below the respective cavity 100 and opening into the cavity 100 to permit

insertion of a suitable tool into slots (not shown) in the spacer 112 for pryingly removing the spacer 112 for disassembling the ladder 20. A similar groove (not shown) may also be provided in the inner side surface of each portion 40 for inserting the tool for pryingly removing the spacer 112 from the other side of the cavity 100. The attachment of a structural member such as platform 22 by means of such a cavity 100 and boss 110 and spacer 112 is described in greater detail in the aforesaid U. S. Patent No. 5,244,291, which is incorporated herein by reference, and will therefore not be described further herein.

The attachment of the platform 22 to both rails 32 in each connected pair is provided to prevent each pair of rails from slidingly disengaging from each other, i. e., in a direction opposite to direction 98, and, as previously discussed, the rails of each connected pair are prevented from disengaging laterally, i. e., in directions 74 or 76. Such a split rail connection allows each rail to extend above the platform 22 to the full height of the ladder 20 as a single piece. Thus, the rails 32 are sturdily connected and cannot come apart, unless disassembly is initiated by removing one or more spacers 112.

Referring to Figs. 1 and 13, each rail 32 includes a plate portion 120 extending inwardly from the elongate portion 42 and downwardly from the intermediate portion 40 and molded, in accordance with principles commonly known to those of ordinary skill in the art to which this invention pertains, to provide a narrow solid (non-hollow) recessed (from both surfaces of the plate portion 120) elongate portion 122 for receiving a screw 124 or other suitable fastener anywhere along the length thereof. The hollow plate portion 120 may have a thickness of, for example, about 1/2 inch and be disposed centrally of the height 60 thereof, and the

solid recessed portion, for example, may have a thickness of about 1/4 inch and a width of about 1/4 inch. The recessed portion 122 extends substantially vertically, i. e., parallel to line 51. A strip 126 is provided to extend horizontally, when the ladder is erected and in position for normal use, between the plate portions 120 of each pair of rails 32, i. e., a strip 126 is provided for rails 32R and another strip 126 is provided for rails 32L. The strip 126 is attached by means of screws 124 or other suitable fasteners received in apertures in the strip and threadedly received in the recessed portions respectively at selected points along the heights thereof. The strips 126 are desirably mounted to be flush with the top of a swimming pool wall which the ladder 20 bridges so as to stabilize the ladder position. Thus, the positions of the strips 126 along the heights of the recessed portions are determined by the height of the swimming pool wall the ladder bridges whereby the ladder is adjustable for swimming pool wall height. For example, the lower surface, illustrated at 128 in Fig. 4, of each pair of intermediate portions 40 is, when the ladder is erected to a position for normal use, located at a height (above the ground or other support surface) of about 54 inches, and the lower surface, illustrated at 130, of each of the strips 126 is, when the screws 124 are inserted at the bottoms of the recessed portions 122 and the ladder is erected and in a position for normal use, at a height of about 48 inches. Each plate portion 120 may, for example, extend downwardly a distance of about 6 inches to achieve height adjustment over 6 inches, and its lower edge may extend from the rail elongate portion 42 a distance, for example, of about 2 inches to orient the recessed portion 122 vertically with a minimum use of material.

For such a ladder, the strips 126 would not be attached

if the swimming pool wall height were the maximum of 54 inches in which event stabilization would be achieved by the lower surface 84 of the intermediate portions 40.

For lesser heights of the swimming pool wall, the strips 126 would be applied to suitable heights. Thus, the ladder 20 is constructed to be adjustable for swimming pool wall height whereby it is unnecessary to provide for manufacture of different size ladders within the adjustment range, and the possibility of customer confusion during assembly is accordingly minimized.

Unlike typical swimming pool wall ladders which have only 4 steps for each stairway, ladder 20 advantageously has 5 steps 34 on about 11 inch spacings for easier climbing, including a ground-engaging bottom step 34B for stabilizing the ladder, for each stairway 24 and 26.

As seen in Fig. 8, each step is a rectangular member which has a notch, illustrated at 140, in its inner edge adjacent each of its ends, and a rail 32R is received in one of the notches 140 and a rail 32L is received in the other notch 140. Each step 34 may, for example, have a length of about 24 inches, a width of about 5 inches, and a thickness of about 1 1/2 inch, a notch width of about I 1/2 inch, and a spacing of each notch from the respective edge of about 1 inch, providing a large tread area of about 5 inches x 18 inches. The tread (not shown) may comprise, for example, four raised parallel strips extending longitudinally of the respective step, the inner two strips being higher than the outer strips. For example, the strips may each have a length of about 15 inches and a width of about 3/4 inch, the height of each outer strip may be about 5/8 inch, the height of each inner strip may be about 3/4 inch. One of the inner strips may have raised letters providing a warning message as well as traction thereon. The remaining strips may have

a traction-providing longitudinally-ridged surface.

Other suitable traction arrangements for the steps may be provided.

A recess 998, located on the outer edge of each step 34, has an aperture 950. Each aperture 950 receives a securing apparatus 999, like a screw, nail or the like. The securing apparatus attaches the step 34 to the rail 32.

Moreover, for further receiving and securing each step 34 (except the bottom step, which will be discussed hereinafter), each of the left and right sides 146L and 146R respectively of the longitudinal portion 42 of each rail 32 is provided with a set of raised support portions as follows. A pair of horizontally spaced portions 150 and 152 provide aligned horizontal surfaces 151 and 153 respectively for supporting the step in a level condition when the ladder is erected and positioned for normal use. Thus, as seen in Fig. 10, the step 22 is lockingly received to rest on surfaces 151 and 153 by portion 154 and held in that position so that it can't tilt backwards by portion 156. Portions 150,152, and 156 may each be raised a distance of, for example, about 3/16 inch.

Referring to Fig. 19, the lower end portion 170 of each rail 32 is tapered downwardly and contains on each side a protruding generally circular portion 172 to be received in notch 997 for the lower step 34B. Portion 172 extends outwardly a distance of about 1/4 inch and tapers downwardly to the rail surface and has a diameter of about 3/8 inch. Notch 997 receives the lower pointed end of the rail and allows rail 32 to swivel within notch 997 so the rail 32 remains level.

The steps 34 for the inner stairway 24 and the upper and bottom steps 34U and 34B for the outer stairway 26 are installed and removed from the rails individually, following the procedure set forth above.

If desired, all the steps 34 for the outer stairway may also be installed and removed from the rails individually.

In order to remove the middle three steps 34M so as to prevent unauthorized persons from using the ladder, in accordance with a preferred embodiment of the present invention, means are provided for removing the steps 34M as a unit as follows. Referring to Figs. 12 to 18, the steps 34M are attached to a pair of parallel elongate frame members 200 which are in turn pivotally connected, above the upper step 34U, to rails 32L and 32R respectively for the outer stairway 26. The frame members 200 are manufactured as pairs, i. e., a right and left members due to the variation of angles and degrees.

Each frame member 200 may, for example, be about 41 inches long, a width of about 2 inches, and a height along its main body of about 7/8 inch. It has an end portion 202 for attachment to a respective rail which has an inner or rail-facing surface 204 which is offset from the inner surface 206 of the main body 208 of the frame member 200 by, for example, about 9/16 inch. The outer surface, illustrated at 212, of the end portion is recessed inwardly, over a portion of its length, from the outer surface, illustrated at 214, of the main body 208. An elongate groove, illustrated at 210, extends longitudinally in the inner surface 204 centrally thereof and from the terminal end of end portion 202 substantially to and terminating short of the other end thereof. Groove 210 may, for example, have a depth of about 7/16 inch, a width of about 5/8 inch, and a length of about 3 11/16 inch. An elongate slot, illustrated at 216, extends entirely through end portion 202 and is located centrally, both length-wise and widthwise, of groove 210. Slot 216 may, for example, have a length of about 2 inches and a width of about 1/4 inch. A button or circular protruding portion 218 is disposed on each

side of each rail 32 approximately level with or slightly above the bottom of plate 120 and adjacent the outer edge thereof. For example, button 218 may have a diameter of about 5/8 inch, a depth of about 1/4 inch to provide thickness for receiving a bolt, and be spaced from the outer edge of the rail a distance of about 1/2 inch. Button 218 is received within groove 210 for attachment of the frame member 200 to the outer side of the respective rail 32. A bolt 220 is received in slot 216 and in apertures which pass through the button 218 and walls of the respective rail 32 and threadedly engaged by nut 226 so that, as illustrated in Fig. 15, the frame member 200 is attached to the outer side of the respective rail 32 to pivot about screw 220 and slide along the length of slot 216.

The inner surface 206 of the main body portion of each frame member 200 has longitudinally spaced notches, illustrated at 222, extending there across, the upper notch for the upper step 34U and the rest of the notches for the other steps 34M, i. e., a total of 4 notches 222 for the step 34U and 3 steps 34M of ladder 20.

These notches 222 are positioned, sized, and shaped so that, when the frame members 200 are attached to the respective rails and lie alongside the rails with the steps attached thereto and with the screw 220 at the upper end of the slot 216, the end portions 224 of the steps 34 will be received within the notches 222 respectively. For example, notches; may each have a width of about 1 5/8 inch and extend to a depth of about 5/8 inch, the bottom of the notch being tapered to correspond to the shape of the step end portions 224, as illustrated in Fig. 17. The steps 34M, with their end portions 224 received in respective notches 222 of the frame members 200, are fixedly attached thereto as by a pair of screws 228 (Fig. 16) or by other suitable means.

Raised portions 232 are portions necessitated by the

molding process to provide the needed wall thickness in the area of the notches 222, as is commonly known in the art to which this invention pertains.

A second elongated button 236 is positioned on each side of each rail 32 below button 218 and inwardly thereof so as to be clear of the respective frame member 200 when the steps 34M are in position on the rails for normal use of the ladder. For example, button 236 may be spaced longitudinally of the respective rail below button 218 a distance of about 1 3/8 inch and spaced from the inner edge of the respective rail a distance of about 3/4 inch.

With the steps 34M engaging the respective rails 32 for normal use thereof, as seen in Fig. 1, they may be removed therefrom by pivoting the frame members 200 with the steps 34M attached about bolt 220 so that the steps 34M are as a group removed from the respective rails 32 by the same pendulum or arcuate movement, illustrated at 238 in Fig. 12, as previously described for removing individual steps 34 which are not attached to frame members. During this movement, the bolt 220 is kept near the upper end, illustrated at 246, of slot 216, as seen in Fig. 13, so that the frame members 200 clear button 236. Fig. 12 shows the frame members 200 pivoted through almost 180 degrees so that the steps 34M are above the platform 22 so that the outer stairway 26 cannot be climbed normally.

Referring to Figs. 17 and 18, in order for the frame members 200 to clear the upper step 34U during the arcuate movement 238 so that the step 34U does not block such movement, suitable cutouts, illustrated at 240, are provided in the frame member surface 206 adjacent the upper notch 222 for upper step 34U.

In order to lock the frame members 200 and steps 34M in the up or removed position of Fig. 12, the removed and raised frame members 200 are allowed to drop

downwardly, as illustrated at 242 in Fig. 13, the length of the slot 216 so that the bolt 220 is at the lower end, illustrated at 244, of the slot. This causes movement of the upper end portions of the frame members 200 in a direction to cause return of the frame members to the lowered position of Fig. 1. to be blocked by buttons 236, as illustrated in Figs. 12 and 14.

To return the frame members 200 and their steps 34M into position on the rails, as seen in Fig. 1, the frame members 200 are raised so that the bolt 220 is in the upper end of the slot 216 whereupon the frame members 200 can clear the button 236. The frame member assembly is then allowed to move downwardly in the previously discussed arcuate or pendulum path, as illustrated at 248 in Fig. 16, so that the steps 34M are moved lockingly into position for normal use of the ladder 20.

During this process of restoring the step position as well as during removal of the steps, the frame members 200 may be moved up or down slightly as required to effect the positioning or removal of the steps 34M.

Thus, there is provided a ladder which is sturdy, can be easily assembled with a minimum of hardware, and can be manufactured for use with different wall heights with a minimum of different parts. Furthermore, there is provided a frame structure for lifting steps away from the rails so as to block access to the upper platform and thereby block access to the swimming pool or other structure for which the ladder is used.

It should be understood that, while the present invention has been described in detail herein, the invention can be embodied otherwise without departing from the principles thereof. For example, another means for attaching the steps may be provided. For another example, frame members may be provided for removing steps from the inner as well as the outer stairway, or no frame members may be provided for removal of steps

from either stairway. For yet another example, the frame members may be provided for lifting upper and lower steps as well as the intermediate steps, or they may be provided to lift a lesser number of the steps.

Such other embodiments are meant to come within the scope of the present invention as defined by the appended claim (s).