Patent Application
20100044152
A male and female blow-molded interconnection system is disclosed in this application.
The present invention relates generally to molded articles which may be blow molded such as a blow-molded ladder or a blow-molded staircase for a swimming pool.
Swimming pool ladders or staircases and various other articles have been made from a plastic material by a process known as “blow-molding,” as exemplified in commonly assigned U.S. Pat. No. 4,023,647 to Confer, commonly assigned U.S. Pat. No. 4,067,614 to Confer et al, and U.S. Pat. No. 4,166,833 to Schurman, all of which patents are hereby incorporated herein by reference. In the process of blow molding, a hollow thin-walled structure is formed having an exterior surface separated from an interior surface by the thin wall, and the hollow structure contains a fluid, in most cases air and/or water.
Pool Ladders with Vandal Guards
By way of background, swimming pool ladders of an A-frame type are positioned straddling a pool wall with the pool side having a ladder for entering and leaving the water (a.k.a., in-pool ladder) and an outside ladder for climbing over the outside of the pool wall (a.k.a., staircase ladder). In the past certain ladders of the foregoing type had relatively unwieldy structures for placing the outside ladder in an inaccessible position so as to prevent unauthorized entry into the pool. Also, insofar as known, ladders of the foregoing type, when disassembled, were not of a size which would fit into a box which was within the dimensions acceptable to commercial shippers. Other types of pool ladders were relatively complicated and difficult to assemble.
In U.S. Pat. No. 6,880,674; St-Hilaire wrote, “A door ladder assembly for use with the [sic] an above ground swimming pool, the assembly comprising a ladder having a plurality of steps, a door with a first side hingedly connected to one side of the ladder and arranged to hingedly move between open and closed positions, a handle being located at the top portion of the door, and a door lock to lock the door in a closed position, the door being provided with a lock operator to unlock the lock, the lock operator being located proximate the handle. The arrangement provides for easy access for an adult, while preventing a child from having access to the unlocking mechanism.” A prior version of a door gate for a pool ladder was disclosed in U.S. Pat. No. 3,225,863 to Ludlow and U.S. Pat. No. 3,968,857 to Bryan. Each of these prior pool ladder barriers are doors that swing on a hinge and are positioned over the A-frame ladder's staircase ladder. These barriers are variations of conventional vandal guards used in other industries.
An alternative vandal guard is disclosed in U.S. Pat. No. 4,579,197 to Spurling. Spurling wrote, “A ladder shield for use in preventing toddlers and the like from climbing the steps of a ladder, such as an above-ground swimming pool ladder, when the ladder or the device to which the ladder is coupled is unattended is disclosed. The ladder shield comprises a rigid yet slightly flexible shell of plastic which is sized and shaped to fit around the front and sides of the ladder so as to block access to the steps on the ladder. The ladder shield is removably secured to the ladder by a removable locking bar which when inserted extends through a pair of holes in the side walls of the shield. The locking bar is secured in place by a lock. When not being used to prevent access to the steps of the ladder, the ladder shield may be used as a mini-foot wash.”
Ladders with a Tambour
A tambour device is defined at www.dictionary.com as “a flexible shutter used . . . in place of a door, composed of a number of closely set wood strips attached to a piece of cloth, the whole sliding in grooves along the sides or at the top and bottom.” Applicant conducted a search to determine if any ladder was associated with a tambour device. The closest reference, not a relevant reference, was U.S. Pat. No. 5,046,582 to Albrecht for a foldable ladder combination with truck cargo carrier. Albrecht wrote, “Commercial truckers frequently have situations arise where they require personal access to the elevated bed of the truck's cargo carrier. The cargo carrier may be mounted on the truck frame itself as in the case of a so-called bob-tail truck; or, the cargo carrier may be a trailer pulled by a truck tractor. In either case, the conventional truck cargo carrier includes an elongated approximately horizontal cargo bed elevated about four to five feet above ground level, and an elongated structural cargo enclosure extending upwardly from, and substantially covering the cargo bed. The cargo bed has a rear end from which cargo is loaded into and unloaded from the cargo carrier, and the structural cargo enclosure has at its rear end right and left side edges in the form of vertical posts extending upward from adjacent the rear end of the cargo bed, and typically has either a single “roll-up” tambour rear door which is engaged in slots disposed at the inboard lateral faces of the posts, or has a pair of swinging doors hinged to such vertical posts, for opening and closing the rear end of the structural cargo enclosure to provide loading and unloading rear access to the structural cargo enclosure and cargo bed.”
Walter, in U.S. Pat. No. 1,911,539, Doernemann, in U.S. Pat. No. 5,536,111, Troester, in U.S. Pat. No. 5,0133,508, and Tokunaga, in U.S. Pat. No. 3,759,043, all disclose a three-dimensional polymeric structure having a male and a female interlocking component. Not one of these disclosures has both interlocking components on a single side of the structure. Moreover, these references disclose both interlocking components contacting the edges of the sides, which allows easier forces to separate the components. As such, none of these references discloses an apparatus that forms at least a male and a female interlocking component on a single side, and preferably not contacting an edge of the side, of the structure.
In commonly assigned U.S. Pat. No. 7,234,780; Lipniarski wrote, “A device and method for forming an indented female connector where the dimension of the indented female connector provides for removing a male molding component without damaging a set of internal ribs formed inside the female connector. A structure comprising an indented female blow-molded connector having a first wall having a top surface and a thickness, with the first wall surrounding an opening. At least one inner wall extends substantially perpendicular to the first wall and borders the opening. At least one rib is formed in the inner wall. A bottom wall is joined to the inner wall and the distance from the rib to the top surface is greater than the thickness of the first wall. The structure further comprising a male connector having a contact edge that, when positioned inside the indented female blow-molded connector, engage the at least one rib, such that the male connector and indented female blow-molded connector are releaseably joinable with one another. Structures can be made that use the indented female blow molded connectors and male connectors including braced stools having three or four legs.” This connection system requires the male component be inserted immediately into a female locking area (a.k.a., an immediate locking system), which is difficult for easy and secure assembly.
Since most blow molded polymeric materials have an immediate locking system, most blow molded polymeric materials having an immediate locking system also require additional interconnection devices be used to secure the assembly. Those additional interconnection devices include and are not limited to rods, screws and other conventional interconnection devices. See U.S. Pat. No. 6,769,513.
The present invention is directed to a blow molded plastic object having a female interconnection system comprising a receiving area and a locking area. We are aware of one patent that discloses a similar a female interconnection system. That patent is commonly assigned U.S. Pat. No. 6,190,600; which is hereby incorporated by reference. In that patent, Lipniarski wrote, “The present invention relates to an apparatus that forms a polymeric structure. The apparatus has a mold plate, a circular trench, a male and female interconnect, a vertical gap filler, and a cylinder. The mold plate has a predetermined geometric design. The circular trench is in the mold plate and the difference between the outer diameter and the inner diameter of the circular trench is a distance D. The male interconnect and the female interconnect are interspaced between each other. Each interconnect rotates within the circular trench and has a base and an interconnection portion. Each base has a width D and slidably mates to the mold plate. Each interconnect portion has a minimum width W which is less than D. The male interconnect portion protrudes downwards relatively from its base to a distance P, likewise the female interconnect portion protrudes upwards relatively from its base to a distance P. The vertical gap filler aligns with the circular trench and has a foundation and an extension. The extension has a width greater than W, a height greater than 2P, and protrudes upwards and downwards from its foundation. The cylinder rotates each interconnect to a predetermined position and raises the vertical gap filler so the foundation connects to the mold plate before any polymeric material is applied to the apparatus to form the polymeric structure. Once the polymeric structure is formed, the cylinder lowers the vertical gap filler until the extension is below the mold plate a distance greater than P and rotates each interconnect so the polymeric structure can be removed from the apparatus.”
The claimed device in U.S. Pat. No. 6,190,600 is a mold for creating a first blow molded object that had a first male structure having a first extension and a first block and a first female structure having first receiving area and a first inhibiting area; and a second blow molded object that had a second male structure having a second extension and a second block and a second female structure having second receiving area and a second inhibiting area. Thereby the first blow molded object and the second blow molded object could have the first male structure inserted into the second receiving area and the second male structure inserted into the first receiving area. Rotating the first blow molded object in relation to the second blow molded object so the first male structure slides into the second inhibiting area and the second male structure slides into the first inhibiting area. The first and second inhibiting areas have no blow molded locking mechanism to secure the respective male structures in the inhibiting areas. Instead the inhibiting areas rely on the walls (which surround [that means a back wall] the male structure except where the male interconnect slides from the receiving area to the inhibiting area and the male extension that protrudes through an opening in the female inhibiting area) to provide a friction fit to inhibit the male structure from releasing itself from the female structure. The lack of a locking mechanism is acceptable for wave dispersion systems but not for ladders which require a more secure system. The present invention solves this problem for blow molded structures that require a secure locking mechanism.
A blow-molded plastic female interconnection system has a receiving section and a locking section. The receiving section receives a male interconnect. The receiving section has a floor aperture shaped to allow the corresponding male interconnect be pushed into the locking section. The floor aperture can have various shapes depending on the shape of the male interconnect. Within the receiving section is a locking projection on the receiving section's back wall and the locking projection has a bottom section that defines a portion of the ceiling of the locking section which has no back wall. When the male interconnect is being pushed into the locking section, the locking projection deforms due to the locking sections no back wall. When the male interconnect is below the locking projection, the locking projection bottom section is positioned on the male interconnect to securely interconnect the male and female units.
The present invention will be described by reference to the following drawings, in which like numerals refer to like elements, and in which;
a illustrates the female opening of
b illustrates
a illustrates the female opening of
b illustrates
a illustrates a cross-section of
c illustrates a cross-section of
b illustrates a transition between
The present invention will be described in connection with a preferred embodiments, however, it will be understood that there is no intent to limit the invention to the embodiments described. On the contrary, the intent is to cover all alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.
Summarizing briefly in advance, the improved plastic pool ladder of the present invention comprises a plurality of molded plastic parts which are of a size so that they can be packaged conveniently for shipping within containers which are readily acceptable by the shippers and which can be assembled by interfitting connections and the use of a simple tool such as an assembler's weight, arms, foot, and possibly a hammer. Additionally, the A-frame of the ladder is assembled by the use of interfitting parts so that it is stable.
Referring now collectively to the various drawing figures and more particularly to
The pool ladder 20 includes a plurality of molded plastic parts, certain of which are identical and assembled in mirror-image relationship to provide the completed pool ladder assembly 20 (
The improved pool ladder 20 includes an A-frame ladder formed of (a) an in-pool ladder 22 having opposed rail structures 30a, 30b (see
As previously stated, the staircase ladder's opposed rail structures 40a, 40b, and steps 14 are blow-molded of plastic, such as, for example, high density polyethylene, polypropylene and/or or other suitable material, to have a hollow interior. Each opposed rail structure 40a, 40b has a bottom edge 62, a proximal edge 63, and a distal edge 64 (proximal and distal edges for the staircase ladder are in relation to the in-pool ladder 22). The pair of identical generally planar parallel vertical opposed rail structures 40a/40b define the sides of the staircase ladder 23 and are interconnected by a series of alternating horizontal steps 14 preferably having suitable non-slip step surfaces. Vertical risers are optional for the staircase ladder except vertical risers cannot be located between the staircase ladder's top step and the platform 60 and/or where the staircase ladder's grooves (described later) extend toward the in-pool ladder. As seen in
The in-pool ladder's opposed rail structures 30a, 30b, and steps 14 are blow-molded of plastic, such as, for example, high density polyethylene, polypropylene and/or or other suitable material, to have a hollow interior. Each opposed rail structure 30a, 30b has a bottom edge 602, a proximal edge 603, and a distal edge 604 (proximal and distal edges for the in-pool ladder are in relation to the staircase ladder 23).
The bottom edge 602 slopes upwardly at or near the proximal edge 603 thereof, as illustrated at 72. Among the steps 14, the bottom edge 602 and the proximal edge 603, the opposed rail structures 30a, 30b can have a plurality of horizontally spaced generally rectangular elongate vertical cut-outs or openings 620. These ventilation openings 620 allow water to circulate through the in-pool ladder system to decrease algae growth.
The opposed rail structures 30a, 30b that extend from the steps 14 toward the pool wall 21 also inhibit individuals from swimming between the in-pool ladder system and pool wall 21. That safety feature was previously disclosed in commonly assigned U.S. Pat. No. 6,102,156 to Lipniarski, which is hereby incorporated by reference herein.
The pair of identical generally planar parallel vertical opposed rail structures 30a, 30b define the sides of the in-pool ladder 22 and are interconnected by a series of alternating horizontal steps 14 preferably having suitable non-slip step surfaces. Vertical risers are not required for the in-pool ladder for reasons disclosed later. As seen in
The steps 14 are conventional polymeric steps as disclosed in commonly assigned U.S. Pat. No. 6,102,156 to Lipniarski except for the interconnection mechanism to the rail structures 30a, 40a, 30b, 40b. Each step 14 has a tread section 140 having a top surface 147, a front side 141, a back side 142, a bottom surface 146 (which can be identical or distinct (see
Protruding from each joining end 143 is a male interconnection 200 (see
For this application we will direct our attention to the “T” shape formation. The “T” shape male interconnection 200 has a length less than the width of the respective rail structure; a maximum height equal to, or slightly less than, the essentially planar section's 144 height; and various widths depending on the “T” shape formation's section. The insertion section protrudes from the joining end a distance greater than one/tenth and equal to or less than half the width of the rail structure.
The insertion section 202 is a narrow section with a predetermined height (H1), a predetermined width (W1), and a predetermined length (L1). The predetermined height, length and width correspond with the rail structure's locking area's first gap area 778 for width and length and walls 784, 786 for height and length, illustrated at
The locking section 206 (see
The bottom surface 212, the front surface 214, the back surface 216, the slope section 250, and the pressure surface 218 are essentially planar surfaces that contact a portion of the respective rail structure at one point when the step 14 is being inserted and/or secured into a rail structure's female opening 300.
The top surface 210 also has an essentially planar surface and it is shaped like the letter “T”. The top of the “T” 222 extends from the narrow section's distal end 204; while the bottom of the “T” (a.k.a., locking ledge) 224 extends toward the broad section's distal end 230. The top of the “T” is 222 width is broader than the insertion section's 202 predetermined width (W1); while the locking ledge 224 is the same width as or wider than the rail structure's female opening's 300 protruding locking mechanism 302, which will be described in greater detail later in this specification.
The pressure surface 218 and the locking ledge 224 contact each other at an angle that will ensure the protruding locking mechanism positions itself over the locking ledge—is at or close (including rounded edges) to 90°. The remainder of the pressure surface 218 and the top of the “T” 222 are interconnected through the rounded transition surfaces. The rounded transition surface and the locking ledge 224 are connected by planar walls (essentially vertical).
As illustrated in
This alignment of the inclined surface 250, portion of the pressure surface 218, and the locking ledge 224 is desired so that when the inclined surface 250 is positioned over the protruding locking mechanism 302 (see
The second section is a locking area 320. The locking area 320 is shaped as the mold for the male interconnection 200 (see
To promote fluid circulation which decreases the growth of undesirable particulates (for example and not limited to bacteria, and mold) and to provide sufficient expansion area not to damage the rail structure and the step 14 when the step is being inserted into the rail structure, the locking area 320 has an aperture 322 (a.k.a., no back wall) on the exterior surface 502 (opposite side of where the step's male interconnection enters the female opening) of the rail structure (see
The protruding locking mechanism 302 can be triangular as illustrated, squared, rectangular, polygoned or a half a ball shape. The only requirements are that the bottom 314 of the protruding locking mechanism 302 be sufficiently protruding to securely lock (contact) the step 14 into the rail structure and able to deform the back wall 780 when the male interconnect 200 is being positioned into the locking area 320. Obviously the step 14 can be removed from the rail structure by excessive forces, such as sledge hammer. In view of the obvious, step 14 is designed not be removed from the rail structures through conventional forces.
In generic terms, the female opening for the T-shaped male connector is a hollow molded object having a first wall having an exterior surface and an interior surface. The interior surface is separated from the exterior surface by a thickness of the first wall. The interior surface defines a cavity to contain a fluid and a portion of the exterior surface surrounds an opening. The opening has the receiving section 310 and the locking section 320.
As illustrated, the receiving section has (A) a first inside wall 770 (see
The first inside wall, the second inside wall, the third inside wall, the first part and the second part of the fourth inside wall, extend substantially perpendicular to the portion of the exterior surface wherein (a) the first inside wall and the second inside wall are opposite each other and (b) (i) the third inside wall and (ii) the first part and the second part of the fourth inside walls are opposite each other.
The back wall 780 has the locking projection 302 that projects toward the opening and has the bottom layer 314 that is the same plane as the first part and the second part of the fourth wall.
The locking section 320 has no back wall (a.k.a., aperture 322—see
The fifth inside wall extends substantially perpendicular to the portion of the exterior surface and the first part of the fourth inside wall. The sixth inside wall extends substantially perpendicular to the portion of the exterior surface and the second part of the fourth inside wall. The first gap area is also between the fifth inside wall and the sixth inside wall. A portion of the eighth inside wall extends substantially perpendicular to the portion of the exterior surface, the fifth inside wall and the sixth inside wall. The first part of the seventh inside wall extends substantially perpendicular to the first part of the fourth inside wall and the fifth inside wall. The second part of the seventh inside wall extends substantially perpendicular to the second part of the fourth inside wall and the sixth inside wall. The remaining portion of the eighth wall defines a base wall of the second gap area and covers the area of the missing back wall. The second part of the first inside wall defines a first side wall of the second gap area and covers the area of the missing back wall; while the second part of the second inside wall defines a second side wall of the second gap area and covers the area of the missing back wall. The second part of the first inside wall, the second part of the second inside wall, the fifth inside wall, the sixth inside wall, the first and second parts of the seventh inside walls have a predetermined height that corresponds to the height of the corresponding male interconnect.
What is unique about this interconnection system is that the entire interconnection is a polymeric material and it does not use any screws, nails, or equivalent structures. Moreover, the male interconnection 200 securely fits within the female opening 300 without damaging the step 14 and/or rail apparatus. This polymeric interconnection of the male interconnection 200 within the female opening 300 is so secure that the connection will not be dislodged under conventional forces being applied to the step 14 and/or rail,apparatus,
Vertical risers were required in the prior art for the in-pool ladder to inhibit individuals from swimming between the steps. Without those vertical risers, there is an increased potential the individual can position themselves by swimming and/or sliding between the steps,. That action allows the individual an opportunity to be stuck between the steps and/or trapped between the in-pool ladder system and pool wall 21. Neither opportunity is desired; and the present invention solves that problem and the pool ladder barrier problem by a different means.
That different means is a tambour gate/barrier device 90. The tambour gate/barrier device 90 is preferably a plurality of polymer hollow tubing 91 interconnected to each other through a thin, flexible polymeric plate 92 (see
The tambour gate/barrier device 90 is positioned within a groove 70 (see
The tambour gate/barrier device 90 has a handle area 900 (see
Obviously if the bottom step is above the ground and a conventional locking system can easily be used, the tambour gate/barrier device 90 can extend to the bottom step and have the aperture positioned above the bottom step to allow the conventional locking system to be used.
When the tambour gate/barrier device 90 is unlocked from the staircase ladder, a person lifts and/or pushes the tambour gate/barrier device 90 to the in-pool ladder in order to expose the staircase ladder's steps. The tambour gate/barrier device 90 remains in the grooves and the grooves for the in-pool ladder are positioned between the steps 14 and the rail structure's proximal edge 602 (closest edge to the pool wall 21) (see
After the swimmers have left the pool, the user pulls and/or pushes the tambour gate/barrier device 90 over the staircase ladder. Thereby the staircase ladder is blocked and the water in the pool can circulates more freely within the ladder area, which decreases the chance of stagnant water and adverse results therefrom.
The bridge structure 50a interconnects rail structures 30a and 40a together and the bridge structure 50a interconnects rail structures 30b and 40b together. The interconnection is performed by a conventional tongue and groove system between the bridge structures and the respective rail structures. To ensure the bridge structures 50a,b do not move, platform 60 interconnects to the bridge structures 50a,b through a tongue and groove system. In the latter embodiment, each bridge structure has a tongue that extends into a corresponding groove in the platform 60; or vice versa. Thereby the platform secures the bridge structures 50a, 50b and the rail structures 30a, 30b, 40a, and 40b together.
Alternatively, each rail structures 30a, 30b, 40a, and 40b can have a handle 700 section that extends through a respective aperture 62a, 62b, 62c, and 62d. Each handle section interconnects to a corresponding handle section—for example handles of rail structures 30a and 40a interconnect together and handles of rail structures 30b and 40b interconnect together to form a respective upside-down “U” figure on and over the platform 60—for safety reasons.
While this invention has been described in conjunction with preferred embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.
