CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Patent Application Serial No. 12/252,789, filed October 16, 2008 which claims the benefit of U.S. Provisional Application Serial No. 61/196,243, filed October 16, 2008, which applications are hereby incorporated by reference in their entirety.

BACKGROUND

1. Technical Field

One aspect of the present invention relates to locking mechanisms, and in another aspect, relates to locking mechanisms for convertible shoes.

2. Background

Manufacturers and retailers have long known the value of a convertible shoe that allows a consumer to detachably secure a number of shoe uppers to a single pair of shoe soles. In addition to the economic advantage of replacing numerous pairs of shoes with a single pair of shoe soles and a variety of uppers, such a shoe has other advantages, including conservation of space during travel. There have been many prior attempts to product such a convertible shoes. See U.S. Pat. Nos. 5,983,528; 5,992,052; 6,349,486; 6,430,846; and 7,318,260.

SUMMARY

According to one embodiment, a locking apparatus is disclosed. The locking apparatus includes a female receptor for locking with a male member. The male member locks with the female receptor by moving the male member with respect to the female receptor in a first direction. The male member is unlocked from the female receptor by moving the male member an additional distance further in the first direction. The female receptor includes resilient arms to hold and release the male member and spring arms that contact the resilient arms.

According to another embodiment, a plastic locking apparatus is disclosed. The locking apparatus includes a female receptor for locking with a male member. The male member locks with the female receptor by moving the male member with respect to the female receptor in a first direction. The male member is unlocked from the female receptor by moving the male member an additional distance further in the first direction. The female receptor includes resilient arms to hold and release the male member and spring arms that contact the resilient arms. The female receptor is formed of a plastic material including an acetal copolymer.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate one or more embodiments of the present invention. These drawings, together with the general description given above and the detailed description of the one or more embodiments given below, are intended to explain the principles of the invention and do not limit its scope, which is solely determined by its claims.

FIGURE 1 is a front view of a locking mechanism according to one embodiment;

FIGURE 2 is a sectional view of a primary housing of a female receptacle according to one embodiment;

FIGURE 3 is a side view of a female receptacle cover according to one embodiment;

FIGURE 4 is a front view of a male latch member according to one embodiment; FIGURE 5 is a side view of a male latch member according to one embodiment;

FIGURE 6 is a sectional view of a male latch member entering a female receptacle according to one embodiment;

FIGURE 7 is a sectional view of a male latch member fully seated in a female receptacle according to one embodiment;

FIGURE 8 is a sectional view of a male latch member being retracted from a female receptacle according to one embodiment;

FIGURE 9 is a sectional view of a male latch member fully seated in a female receptacle include springs according to one embodiment;

FIGURE 10 is a sectional view of a male latch member fully retracted from a female receptacle including springs according to one embodiment; and

FIGURE 11 is a plan view of a convertible shoe according to one embodiment of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS

OF THE PRESENT INVENTION

As required, detailed embodiments of the present invention are disclosed herein. However, it is to be understood that the disclosed embodiments are merely exemplary of an invention that may be embodied in various and alternative forms. Therefore, specific functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for the claims and/or as a representative basis for teaching one skilled in the art to variously employ the present invention. Except where expressly indicated, all numerical quantities in this description indicating amounts of material or conditions of reaction and/or use are to be understood as modified by the word "about" in describing the broadest scope of the present invention. Practice within the numerical limits stated is generally preferred.

The description of a single material, compound or constituent or a group or class of materials, compounds or constituents as suitable for a given purpose in connection with the present invention implies that mixtures of any two or more single materials, compounds or constituents and/or groups or classes of materials, compounds or constituents are also suitable. Also, unless expressly stated to the contrary, percent, "parts of," and ratio values are by weight. Description of constituents in chemical terms refers to the constituents at the time of addition to any combination specified in the description, and does not necessarily preclude chemical interactions among constituents of the mixture once mixed. The first definition of an acronym or other abbreviation applies to all subsequent uses herein of the same abbreviation and applies mutatis mutandis to normal grammatical variations of the initially defined abbreviation. Unless expressly stated to the contrary, measurement of a property is determined by the same technique as previously or later referenced for the same property.

Where published documents are referenced in this application, the disclosures of these documents in their entireties are hereby incorporated by reference into this application to more fully describe the state of the art to which one or more of the embodiments of the present invention pertain.

Prior attempts to product a convertible shoe have not been successful in that they suffer from one or more disadvantages, including complexity of manufacture, difficulty of use, unreliability and/or unconventional appearance. U.S. Pat. No. 5,992,052 to Jneid proposes attachment of a shoe upper to a shoe sole using snap fasteners. Another proposal, which is set forth in U.S. Pat. No. 5,983,528 to Hartung, discloses the use of zippers. These proposals have failed to provide adequate functionality because they are overly complex and do not provide a hidden-type connection. Other proposed convertible shoes have attempted to substantially hide the connection between the vamp and sole, including U.S. Pat. No. 6,349,486 to Lin, which utilizes clips, and U.S. Pat. No. 6,430,846 to Lin, which uses a push button locking mechanism. These attempts have not adequately solved the problem of ease of manufacturing while providing secure locking, a hidden view, and facility of use by the consumer. For instance, U.S. Pat. No. 6,430,846 to Lin requires difficult and expensive manufacturing techniques to insure that the push button is accurately positioned and to prevent foaming material from fouling the internal components. In addition, the push button is visible, or, if attempted to be hidden, presents substantial manufacturing difficulty and increased costs. Furthermore, such mechanisms must be located along the outer perimeter of the shoe sole such that the push button is accessible, thus preventing its application to thong style shoe designs in which one upper connection is positioned toward the center and away from the perimeter of the shoe sole.

Another proposal for a convertible shoe is disclosed in U.S. Pat. No.

7,318,260 to Pearce, which provides a quick release locking mechanism and method, especially for a hidden-type convertible shoe. One or more of the embodiments disclosed in U.S. Pat. No. 7,318,260 overcome one or more of the problems with respect to one or more of the prior proposals identified above.

One or more embodiments of the present invention also overcome one or more of the problems with respect to one or more of the prior proposals identified above. For example, Figure 1 depicts a front view of locking mechanism 10 according to one embodiment of the present invention. Locking mechanism 10 includes female receptacle 12 and male latch member 14. Figure 2 depicts a sectional view of primary housing 16 of female receptacle 12. Insertion guide 18 is formed in the bottom of female receptacle 12. Primary housing 16 houses resilient arms 20 with capture notches 22 for holding male latch member 14. Figure 3 depicts a side view of cover 24, which includes insertion guide 26, stops 28 along the top perimeter of cover 24. Pins 30 are disposed on the side perimeters of cover 24 and pins 32 are disposed on the body of cover 24, as depicted by Figure 3. Pins 30 and 32 are inserted into registers 34 and 36, respectively, of primary housing 16 to complete assembly of female receptacle 12 and to form female receptacle cavity 38.

Referring now to Figures 4 and 5, male latch member 14 includes arbor 40, substantially planar handle 42 at the proximal end of male latch member 14, catch apparatus 44 at the distal end of male latch member 14. Slidable annulus 46 is slidably mounted to arbor 40 for movement between catch apparatus 44 and the lower margin of substantially planar handle 42. In one or more embodiments, the slidable annulus 46 is permanently mounted to arbor 40.

Referring now to Figures 6 and 7, locking of mechanism 10 is achieved by pressing male latch member 14 in a first direction into female receptacle 12, such that resilient arms 20 are urged open by, and then springably close behind, catch apparatus 44. Stops 28 prevent upward travel of resilient arms 20 tending to be induced by separation forces while locking mechanism 10 is in use. Figure 7 depicts a sectional side view of locking mechanism 10 in a locked position. As shown in Figure 7, slidable annulus 46 rests upon resilient arms 20 while locking mechanism

10 is in the locked position.

Referring now to Figure 8, unlocking of mechanism 10 is achieved by pressing male latch member 14 further in the first direction into the female receptacle 12 such that slidable annulus 46 urges open resilient arms 20 while being pressure captured in capture notches 22 and is subsequently dislodged by catch apparatus 44 during upward withdrawal in a second direction of male latch member 14, thereby completely unlocking mechanism 10.

As depicted in Figure 9, springs 48 are disposed within female receptacle cavity 38 to reduce creep of resilient arms 20 tending to be induced by slidable annulus 46 resting upon resilient arms 20 while locking mechanism 10 is in the locked position over multiple uses of locking mechanism 10. Springs 48 include spring arms 50 disposed below resilient arms 20. Spring arms 50 are in a first position while the locking mechanism 10 is in the locked position. Springs 48 are force fit into female receptor cavity 38 according to one embodiment. In other embodiments, springs 48 are fixedly mounted at their base to the base of primary housing 16.

As depicted in Figure 10, spring arms 50 springably extend upward into a second position after withdrawal of male latch member 14 from female receptacle 12. The upward force exerted by spring arms 50 against resilient arms 20, during and after the movement from the first position to the second position helps to reduce creep of resilient arms 20, thereby maintaining opening length 52 between resilient arms 20 over multiple uses of locking mechanism 10. In one or more embodiments, maintaining the opening length enhances the reliability of the locking mechanism. Excessive creep of resilient arms 20 may cause unintended unlocking of the locking mechanism.

According to Figure 11, a number of female receptacles 12 are embedded permanently in shoe sole 54 and a corresponding number of male latch members 14 are affixed to the lower perimeter of shoe upper 56 at their substantially planar handles 42. In this embodiment, shoe upper 56 is detachably mounted to the shoe sole 54 such that uppers of various styles, colors, and functionality may be engaged with a single pair of shoe soles. To facilitate a hidden-type connection, the top surfaces of the female receptacles 12 are recessed into shoe sole 54 such that when uppers 56 are mounted to sole 54, that portion of the upper attached to planar handle 42 of male latch member 14 resides substantially below the top surface of shoe sole 54, thus giving fully assembled convertible shoe 58 the appearance of a conventional shoe.

Engagement of shoe upper 56 to shoe sole 54 is accomplished by grasping that portion of the upper affixed to planar handle 42 and pressing male latch member 14 into female receptacle 12 in the first direction. Locking may be indicated by an audible clicking sound that signals that catch apparatus 44 has been captured by the resilient arms 20. Disengagement is achieved by grasping upper 56 at planar handle 42 and pushing male latch member 14 deeper into female receptacle 12 in the first direction, thus forcing slidable annulus 46 to urge open resilient arms 20. During this action, slidable annulus 46 is removably captured by resilient arm notches 22. An audible clicking sound may signal that slidable annulus 46 has been captured. Male latch member 14 is then withdrawn in the second direction as previously described. This embodiment provides a secure, hidden-type connection that can be easily and quickly engaged and disengaged, while providing the appearance and aesthetic appeal of a conventional shoe.

The locking mechanisms of one or more embodiments of the present invention have numerous applications, including but not limited to, application to accessories such as belts and purses as well as utility items such as containers, luggage, and the like.

The locking mechanisms of one or more embodiments of the present invention may be capable for mass production through plastic injection molding using a variety of plastic materials, including polyoxymethylene and nylon resins and their polymers to form the female receptacle, male latch member, and/or the slidable annulus, such that optimum operation, strength, and durability are achieved.

In one embodiment, the plastic material is comprised of one or more polymers derived from one or more acetal copolymer compounds. Such plastic material may be utilized to form the female receptacle, the male latch member, and/or the slidable annulus. It has been unexpectedly found that female receptacles made of plastic materials including one or more acetal copolymer compounds is superior to female receptacles made of plastic materials including one or more acetal homopolymers with respect to addressing the resilient arm creep issue. Further, acetal copolymer female receptacles and male latch members achieve greater sewability into shoe soles and shoe uppers, respectively, than acetal homopolymer female receptacles, according to one or more embodiments. The following experimental data shows the criticality of acetal copolymer compounds for use in forming the female receptacle, male latch member, and the slidable annulus according to one or more embodiments. EXAMPLE 1

Five samples of a locking mechanism, including a female receptacle, a male latch member and slidable annulus, were formed with DuPont (TM) DELRIN 500P acetal resin, which is an acetal homopolymer compound, using a plastic injection molding process. Other DuPont (TM) DERLIN compounds include DERLIN 111 P, 100, 300P, 31 IP and 500T. The opening between resilient arms after fabrication and before the experiment was 4.3 mm. If the opening exceeds 5.0 mm, which may occur with excessive creep of the resilient arms, the locking mechanism may malfunction with unintended opening from a closed position.

Three experiments were then conducted on each of the samples. The first experiment included resting the slidable annulus on the resilient arms (as depicted in Figure 8) for a period of 4 hours, releasing the male latch member from the female receptacle, and then measuring the opening recovery after release. The second experiment increased the resting period to 8 hours. The third experiment increased the resting period to 24 hours. The following table shows the results of the experiments.

Table 1

When the resting period was 4 hours, the experimental data shows that the resilient arms take about 20 minutes to recover to avoid an opening exceeding 5.0 mm, which may cause the locking mechanism to malfunction.

When the resting period was 8 hours, the experimental data shows that the resilient arms take about 1 hour to recover to avoid an opening exceeding 5.0 mm, which may cause the locking mechanism to malfunction.

When the resting period was 24 hours, the experimental data shows that the resilient arms take about 24 hours to recover to avoid an opening exceeding 5.0 mm, which may cause the locking mechanism to malfunction. EXAMPLE 2

Five samples of the locking mechanism, including the female receptacle, the male latch member and slidable annulus, were formed with DURACON M90-44 acetal plastic material, which is an acetal copolymer compound, using a plastic injection molding process. DURACON M90-44 acetal plastic material is available from Polyplastics Co., Ltd. of Tokyo, Japan. The opening between the resilient arms after fabrication and before the experiment was 4.3 mm. If the opening exceeds 5.0 mm, which may occur with creep of the resilient arms, the locking mechanism may malfunction with unintended opening from a closed position.

Four experiments were then conducted on each of the samples. The first experiment included resting the slidable annulus on the resilient arms (as depicted in Figure 8) for a period of 4 hours, releasing the male latch member from the female receptacle, and then measuring the opening recovery after release. The second experiment increased the resting period to 8 hours. The third experiment increased the resting period to 24 hours. The fourth experiment increased the resting period to 100 hours. The following table shows the results of the experiments.

Table 2

When the resting period was 4 hours, the experimental data shows that the resilient arms take about 10 minutes to recover to avoid an opening exceeding 5.0 mm, which may cause the locking mechanism to malfunction.

When the resting period was 8 hours, the experimental data shows that the resilient arms take about 10 minutes to recover to avoid an opening exceeding 5.0 mm, which may cause the locking mechanism to malfunction.

When the resting period was 24 hours, the experimental data shows that the resilient arms take about 40 minutes to recover to avoid an opening exceeding 5.0 mm, which may cause the locking mechanism to malfunction. When the resting period was 100 hours, the experimental data shows that the resilient arms take about 24 hours to recover to avoid an opening exceeding 5.0 mm, which may cause the locking mechanism to malfunction.

As can be appreciated from a comparison of Examples 1 and 2, the use of an acetal copolymer material reduces the creep of the resilient arms as compared to the acetal homopolymer material. Therefore, with references to these experiments, enhanced reliability of the locking mechanisms may be achieved by using the acetal copolymer material.

Non-limiting examples of suitable acetal copolymer plastic materials include CELCON M90, M90-FM050 and F90-45 black acetal copolymers available from Ticona Engineering Polymers of Florence, Kentucky; IUPITAL F20-03 acetal copolymers available from Mitsubishi Enginerering-Plastics Corp. of New York, New

York; and DURACON M90-44 acetal copolymers available from Polyplastics Co.,

Ltd. of Tokyo, Japan. Other materials that may be used in accordance with one or more embodiments of the present invention include BASF Ultraform N 2320, POM

DM120 and PA 66-A3K.

While embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention.