Pet door hinge

Not Applicable.

Not Applicable.

1. Field of Invention

The invention relates to a hinge for a pet door. More specifically, this invention relates to a flexible hinge adapted to resist damage or breakage resulting from undesirable forces applied to the hinge during the normal course of operation.

2. Description of the Related Art

Conventional pet doors have a movable flap residing within a frame. Soft flap pet doors take advantage of the flexibility of the flap to allow ingress and egress, such as that shown and described by Davlantes in U.S. Pat. No. 4,408,416. Hard flap pet doors must use a hinge mechanism to allow for movement of the flap. There are many basic hinge mechanisms commonly employed. One example of a common hinge mechanism is the molding of the shaft and the hinge tube as part of the flap and the frame, such as that shown and described by Green, in U.S. Pat. No. 4,776,133. Another example, is the use of a cam resting on a shelf, such as that shown and described in by Marsh, et al., in U.S. Pat. No. 6,385,909, or a cam resisted by a biasing member such as that shown and described by Pennock in U.S. Pat. No. 3,978,616. In yet another example, the flap and the frame may be connected by conventional hinges, such as that shown and described by Peterson in U.S. Pat. No. 5,581,940.

Each of the hard flap pet doors share the common concern of the hinge mechanism being subjected to potentially damaging forces, for example, the over-rotation of the flap. If the flap is pushed beyond the rotational limits afforded by the hinge mechanism, some portion of the rigid structure is forced to give. This can result in the breakage of the flap or the frame and/or the destruction of the hinge mechanism including but not limited the breakage of the shafts or the hinge tubes, the separation of the hinge from the flap or the frame, the breakage of the cam member, or merely the deformation of the hinge mechanism outside of tolerances resulting in unreliable performance. The same potential for damage often results from the physical construction of the pet door. When the hard flap rotates until it is contact with the top of the frame member, the pivot point is moved from the hinge mechanism to the point of contact between the frame and the flap. This results in lateral (i.e., non-rotational) forces, which a conventional hinge is not designed to accommodate, being applied to the hinge.

A hinge for use in a pet door is shown and described. The hinge mechanism includes a shaft is received by a shock-absorbing bearing. The bearing is received by a sleeve. The bearing rotates within the sleeve to allow pivoting of the flap. In the event of undesirable forces being applied to the hinge mechanism, a deformable and resilient material forming the core of the bearing flexes to prevent damage to or destruction of the hinge mechanism or the pet door.

The above-mentioned features of the invention will become more clearly understood from the following detailed description of the invention read together with the drawings in which:

FIG. 1 illustrates a front perspective view of a pet door incorporating the hinge of the present invention;

FIG. 2 illustrates a rear perspective view of a pet door incorporating the hinge of the present invention;

FIG. 3 illustrates an exploded view of the pet door hinge assembly, including the frame;

FIG. 4 illustrates an exploded view of the pet door hinge assembly;

FIG. 5 illustrates the operation of the pet door hinge when the flap is rotated within the defined limits of movement;

FIG. 6 illustrates the operation of the pet door hinge when the flap is rotated into engagement with the frame member; and

FIG. 7 illustrates an exploded view of an alternate embodiment of the pet door hinge assembly.

A pet door hinge adapted to tolerate undesirable and potentially-damaging forces occurring within the normal course of operation of the pet door is shown in the figures and described herein. The general construction of a pet door is well known to those skilled in the art and, therefore, is not described in detail herein. Specifically, frames, flaps, closure mechanisms, locking mechanisms, and other common features are deemed to be within the purview of one of ordinary skill in the art. The pet door hinge described herein allows the movement of the flap and provides shock-absorption in the event that undesirable forces, such as lateral or excessive rotational forces, are applied to the hinge mechanism. It will be understood by those skilled in the art that the pet door hinge described herein can be used in various pet doors without departing from the scope and spirit of the present invention.

FIG. 1 illustrates a pet door incorporating one embodiment of a pet door hinge 100 of the present invention as viewed from the front. The pet door includes and a hard flap 102 located in a frame member 104 . FIG. 2 illustrates the opposite side of the pet door of FIG. 1 once again showing the pet door hinge 100 of the present invention.

FIG. 3 illustrates an exploded view of the hinge 100 . In the illustrated embodiment, the flap 102 has an integrally-molded shaft 300 with a substantially square cross-section backed by a substantially elliptical shoulder 302 and the frame member 104 includes a sleeve 310 . A bearing 304 serves to mate the shaft 300 and the sleeve 310 to complete the hinge 100 . The bearing 304 includes an outer ring 306 and a cushion 308 . The outer ring 306 is adapted to be received within the sleeve 310 . The bearing 304 rotates within the sleeve 310 to allow the flap 102 to pivot within the frame 104 and thereby allow ingress and egress through the pet door. The circular shapes of the bearing 304 and the sleeve 310 are generally conducive to smooth pivoting of the flap 102 ; however, friction reduction and the reduction of binding of the hinge 100 can be aided by the use of a lubricant, such as silicon oil, or fabrication of the hinge from a slf-lubricating materterial, such as Delrin® from E.I. du Pont de Nernours and Company (polyoxymethylene), nylon, polypropylene, a material coated with Teflon® (fluoropolymer), or a material impregnated with silicon. A lip or, as illustrated in FIG. 3 , a wall 312 serves to limit the depth of the sleeve 310 with respect to the bearing 304 and hold the bearing 304 securely on the shaft 300 when the hinge 100 is assembled. Similarly, the shoulder 302 serves as a stop for the bearing 304 on the flap-side of the hinge 100 .

The void defined by the outer ring 306 is substantially filled with a cushion 308 that is generally secured to the outer ring 306 . The cushion 308 is fabricated from a polymeric material that is resilient and deformable, for example, rubber polyisoprene. In one embodiment, the cushion 308 defines a plurality of through-openings that provide room for the deformation of the cushion 308 in the event of the undesirable forces on the hinge 100 . The shape, size, number, and position of the through-openings are selected to provide the desired amount of deformation. In an alternate embodiment, the material from which the cushion 308 is fabricated exhibits sufficient compressibility to provide the desired deformation without the use of through-openings. Those skilled in the art will recognize other materials which could be used without departing from the scope and spirit of the present invention including closed or open cell foam.

The cushion 308 defines an opening adapted to receive the shaft 300 . The shaft 300 is generally shaped so as not to rotate within the cushion 308 opening in the presence of normal operating forces required to move the flap 102 . Typically, any geometric shape having corners tends to resist rotation, for example the substantially square-shaped shaft illustrated in the FIGS. Although generally deformable, the cushion 308 is fabricated from a material that does not deform under the normal operating forces required to move the flap 102 , i.e., while the bearing freely rotates. In the most basic embodiment, the engagement of the shaft 300 and the cushion 308 is in the fashion of a mortise-and-tenon. Other embodiments incorporate additional features such as those illustrated in the Figures.

FIG. 4 illustrates an exploded view of the hinge 100 from the opposite viewpoint of FIG. 3 . The illustrated bearing 304 includes an inwardly-projecting extension 400 adapted to engage a surface of the shaft 300 and provide a non-deformable support for the shaft 300 to act against. Generally, the extension 400 is generally shaped and sized similarly to the shaft 300 . When the extension 400 is employed, the extension 400 and the cushion 308 cooperate to substantially fill the void defined by the outer ring 306 and to secure the bearing 304 to the shaft 300 . As illustrated, the extension 400 has approximately the same width as the shaft 300 and both the extension 400 and the shaft 300 have substantially equal heights, which are each approximately one-third of the internal diameter of the outer ring 306 . The remainder of the internal area of the ring 306 not occupied by the extension 400 and the shaft 300 is occupied by the cushion 308 . The dimensions are selected so that the shaft 300 is generally centered within the bearing 304 . Those skilled in the art will recognize other dimensions and arrangements for centering the shaft 300 within the bearing 304 without departing from the scope and spirit of the present invention.

A further refinement visible in FIG. 4 is the addition of a keyway 402 in the shaft 300 and a corresponding key 404 , which in the illustrated embodiment protrudes from the extension 400 . The key 404 and keyway 402 serve to properly align the bearing 304 and the shaft 300 and to further insure that the shaft 300 and the bearing 304 rotate together. It will be recognized by those skilled in the art that the inwardly projecting extension 400 and the key 404 and keyway 402 are refinements to the basic hinge 100 described herein. Such refinement offers advantages over the basic embodiment but are not required to fall within the scope and spirit of the present invention.

FIG. 5 illustrates the rotation of the hinge 100 within the normal movement range of the flap 102 . FIG. 6 illustrates the resilience of the hinge 100 when the hinge 100 is subjected to undesirable non-rotational forces. In the illustrated embodiment, the flap 106 is pushed into contact with the frame member 104 , which moves the pivot point of the flap 102 from hinge 100 to the point of contact 600 between the flap 102 and the frame member 104 . As the flap 102 is substantially rigid, further upward movement of the flap 102 when so engaged with the frame member 104 results in undesirable lateral forces being applied at the hinge 100 . These lateral forces are not compatible with the rotational design of the hinge mechanism 100 . Accordingly, the cushion 308 compresses to accommodate these undesirable forces. The deformation is represented by the flattening of some of the cushion through-openings and the acceptance of the cocked relationship between the shaft and the extension. In this manner, the hinge mechanism 100 resists breakage or other damage. When the undesirable forces cease, the resilient nature of the cushion 308 allows the bearing 304 and the shaft 300 to return to their normal relative positions.

Herein, the shaft 300 has been shown and described as part of the door flap 102 and the sleeve 310 has been shown and described as part of the door frame 104 . It will be understood by those skilled in the art that relative placement of the shaft 300 and the sleeve 310 can be reversed without departing from the scope and spirit of the present invention. FIG. 7 illustrates an alternate embodiment the hinge 700 where the sleeve 702 is incorporated into the flap 102 and the shaft 704 is incorporated into the frame 104 . The bearing 304 remains carried by the shaft 704 and received by the sleeve 702 . The reversed pet door hinge 700 operates identically to the other pet door hinge embodiment 100 .

A pet door hinge adapted to tolerate undesirable and potentially damaging forces applied during normal operation of the pet door has been shown and described. The hinge mechanism incorporates a bearing have a core formed from a resilient, deformable polymeric material forming the core of the bearing. The core gives under pressure in order to prevent damage to or destruction of the hinge mechanism or the pet door. Those skilled in the art will recognize the geometric shapes and relative dimensions described herein are exemplary and represent easily moldable parts. Other shapes and dimensions could be used without departing from the scope and spirit of the present invention.

While the present invention has been illustrated by description of several embodiments and while the illustrative embodiments have been described in detail, it is not the intention of the applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and methods, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of applicant's general inventive concept.