Length Adjustable Clasp Assembly

The present invention relates to clasps, and more specifically to length adjustable clasps.

Clasps are used with straps in various articles, such as garment belt straps and wristwatch band straps. Often, the length adjustability of a fastened clasp and strap can be limited to coarse adjustments.

In one form, a clasp can be a buckle that is connected to the first end of a strap where the second end of the strap has multiple regularly spaced holes through which one or more buckle prongs or pins are fastened. The operation of this type of buckle with a strap is well known. The fixed regular spacing of the holes in a strap provides coarse adjustment of the length of the fastened buckle and strap. When a buckle and belt strap are used to secure a person's pants at their waist, the locations of holes may cause the belt's fit will be too tight or too loose. A person's preferred or needed belt length may change over time as well, so a custom length strap may not provide a good fit in the long term. There are pant belt length adjustment systems that provide various solutions and are typically complex, require effort to change their size adjustment, and have limited styles due to the construction of a specialized buckle or belt. A wristwatch strap is another example of where a buckle and strap may be used and provide limited adjustability based on the spacing of holes in the strap.

In another form, a fold-over clasp may be used with a link-style wristwatch strap. A fold-over clasp is a common type of clasp where the clasp is a hinged metal loop that is attached to one strap and folds over a bar attached to another strap. The bar acts as an anchor point for the clasp. After the clasp is folded over the bar, it is snapped shut, creating a secure hold around the bar. A link-style wristwatch strap is constructed from interconnected pieces and its length is coarsely adjusted by removing links. If the adjustment from link removal does not provide a proper fit for a person's wrist then the strap will be too tight or too loose.

This application relates to a clasp assembly that provides a length adjustment mechanism.

A first component of the clasp assembly, termed a chape, integrates a threaded connector with a strap attachment component. The chape is attached to the first end of a strap, such as a belt strap or wristwatch strap, and has a threaded connector for attaching to a second component of the clasp assembly.

The second component of the clasp assembly, termed a clasp component, integrates a threaded connector with a strap fastening component. The clasp component includes at least one component to facilitate fastening to the second end of the strap, and has a threaded connector that mates with the chape's threaded connector counterpart. The clasp component may include active components, such as a buckle and prong or pin for fastening into holes in the second end of the strap as commonly found in belt buckles. The clasp component may include passive components, such as a bar around which the active side of a wristwatch fold-over clasp latches. Clasp components may take many forms.

The threaded connectors may consist of a matching set of an externally threaded cylindrical rod and a component with an internally threaded cylindrical hole. A length adjustment is achieved by rotating the clasp component relative to the chape, thereby threading them together or apart, in order to lengthen or shorten the distance between the chape and clasp component. Changing the distance between the chape and clasp component results in adjustment of the fastened length of the clasp assembly and strap.

This clasp assembly provides for simple and easy length adjustment for a fastened clasp and strap, and is adaptable to a range of clasp and strap varieties and uses.

The following will describe details of clasp assemblies that include a chape and clasp component that can be threaded together or apart to achieve a length adjustment of the assembly. Some examples of clasp components and chapes are provided first to aid in understanding the components before showing examples of clasp assemblies.

Figures are representative of functional parts and do not represent a specific style or design that must be used to construct a length adjustable clasp assembly. Figures are scaled to show details and are not intended to represent required part sizes.

shows an embodiment of a clasp component that includes a frame-style buckle, a hingethat can pivot relative to the buckle, a prongthat is fixed to hinge, a hingethat can pivot relative to the buckle, a cylinderthat is fixed to hinge, and an internally threaded cylindrical holealong the longitudinal axis of cylinder. In a complete clasp assembly, the threaded holewould thread onto an externally threaded cylindrical rod of a chape (such as). A length adjustment would be made by threading the chape and clasp component together or apart to change the overall length of the clasp assembly. The prongwould fasten through a hole in a strap (not shown) to secure the clasp and strap.

shows another embodiment of a clasp component including a frame-style bucklethat is hinged on a rodand can pivot relative to an externally threaded cylindrical rod. The threaded rodis perpendicular to and fixed to rod. Each of two prongsare fixed to one of two hingesthat pivot on rod, and the two prongscan pivot relative to the buckle. In a complete clasp assembly, the threaded rodwould thread into a threaded hole of a chape (such as). A length adjustment would be made by threading the chape and clasp component together or apart to change the overall length of the clasp assembly. The prongswould fasten through holes in a strap (not shown) to secure the clasp and strap.

shows another embodiment of a clasp component including a plate-style bucklewith attached prong, and both ends of U-shaped buckle wireperpendicular to and attached to the buckle. An externally threaded cylindrical rodis perpendicular to and fixed to a cylindrical tube hinge. The buckle wirepasses though the hingeto allow the buckleto pivot relative to the threaded rod. The threaded rodwould thread into a threaded hole of a chape (such as).

shows an embodiment of a chape that includes a securing barthat is perpendicular to and fixed to cylinder, and an internally threaded cylindrical holealong the longitudinal axis of cylinder. The chape would be enveloped and held in place by a strap (not shown) with the internally threaded cylindrical holeaccessible through a hole in the strap. In a complete clasp assembly, the clasp component (such as) would thread into the threaded hole.

shows a cutaway view of thechape including a securing barthat is fixed to cylinder, and an internally threaded cylindrical holein the cylinder. The internal threads may encompass the entirety of the cylindrical hole or just a portion of the cylindrical hole as shown.

shows another embodiment of a chape including a U-shaped attachment platewith two parallel side plates and an end plate, and externally threaded cylindrical rodperpendicular to and fixed to the end plate of attachment plate. The side plates have aligned attachment holes. A strap (not shown) would be held between the side plates of the attachment platewith fasteners through the attachment holes. A clasp component (such as) would thread onto the threaded rod.

shows another embodiment of a chape including a flat attachment plate, and internally threaded cylindrical hole. The attachment platehaving attachment holes. The chape would be enveloped by a strap (not shown) with the threaded holeaccessible through a hole in the strap, and fastened to the strap through the attachment holes. A clasp component (such as) would thread into the threaded hole.

shows an embodiment of a clasp assembly with an attached strap. A clasp component, similar to the one shown in, including a frame-style buckle, a prongthat can pivot relative to the buckle, and a cylinderthat can pivot relative to the buckle, where cylinderhas an internally threaded cylindrical hole for coupling with a chape. A chape, similar to the one shown in, including an externally threaded cylindrical rodthat is threaded to the clasp component's internally threaded counterpart in cylinder. An attachment plateis attached to the first end of a strapvia fasteners, such as rivets or screws, through attachment holes similar toattachment holes. Prior to the strapbeing inserted through the open space within the buckle, the length of the clasp assembly is adjusted by rotating the clasp component relative to the chape to thread them together or apart, thereby adjusting the length of the buckle and strap. A prongmay be fastened through a holein the second end of the strapto secure the clasp and strap.

shows another embodiment of a clasp assembly with an attached strap. A clasp component, similar to the one shown in, including a frame-style buckle, two prongsthat can pivot relative to the buckle, and an externally threaded cylindrical rodthat can pivot relative to the buckle. A chape, similar to the one shown in, including a cylinderwith an internally threaded cylindrical hole that is threaded onto the clasp component's externally threaded counterpart. The first end of a strapfolds over the chape and envelopes it. Fasteners, such as rivets or screws, go through the two layers of the folded over strapand hold the straptight against the chape to keep the chape in its proper location. A securing rodprevents the chape from rotating when the clasp component is threaded into or out of the threaded hole of cylinder. The first end of the straphas a hole (not shown) where it wraps over the opening of the threaded hole of cylinderto allow the threaded rodto pass through the strapand into the threaded hole of cylinder. Prior to the strapbeing inserted through the open space within the buckle, the length of the clasp assembly is adjusted by rotating the clasp component relative to the chape to thread them together or apart, thereby adjusting the length of the buckle and strap. Two prongsmay be fastened through holesin the second end of strapto secure the clasp and strap. A strap keepermay be secured to the strap by fastenersand used to hold excess length of the second end of strap in place.

shows an embodiment of a chape for a link-style wristwatch strap including interconnected links, link interconnection pins, and an end linkhaving an internally threaded cylindrical holefor coupling with a clasp component. The interconnection pinspass through aligned holes in linksand end linkto hold the chain of individual links together while allowing the strap to be flexible.

shows an embodiment of a clasp component for a link-style wristwatch strap including a linkcontaining a fold-over clasp bar, and externally threaded cylindrical rod. A fold-over clasp is a common type of clasp used with wristwatches. The fold-over clasp would be fixed to the opposing wristwatch strap (not shown) and would fasten to the clasp bar. The threaded rodwould thread into a threaded hole of a chape (such as). A length adjustment would be made by threading the chape and clasp component together or apart prior to securing the fold-over clasp to the clasp bar. In this embodiment, it is shown that for some designs it may be preferred for a passive component to be threaded onto a chape that is connected to the first end of a strap, and the active component of a clasp to be attached to the second end of a strap.

Not all straps are contiguous, such as wristwatch straps that may be formed from two separate pieces. Also, some garment belt straps are two independent straps, such as ones that fasten on one end to pant belt loops instead of a single strap encircling the waist.

The style of a clasp or buckle may vary to meet a designer's preference as many styles may be designed in this way to have an adjustable length. Clasps may include prongs, snaps, magnets, hooks, claws, and others fastening devices.

A chape may attach to a strap in any functional manner, only a few examples are provided here. Exposed fasteners are not required. For example, screws from the back side of the chape may attach the strap. Alternatively, the chape may clamp onto, snap onto, hook onto, or slide onto a strap for attachment.

A garment strap may be designed to be reversible by rotating a clasp component 180-degrees relative to a chape, allowing the strap to be worn with the opposite side exposed. This would result in a change in the clasp length as well.

Multiple clasp components can be provided with a chape to provide interchangeable clasp component styles, such as different colors, materials, designs, sizes, shapes, and themes. Clasp components are changed by completely unthreading one clasp component from a chape and threading a different clasp component onto the chape.

A clasp component and chape may be designed to prevent completely unthreading from each other in order to prevent disassembly.

A strap or strap links may be made from any appropriate natural or synthetic material, such as leather, rubber, canvas, vinyl, fabric, elastic fabrics, metal, plastic, wood, ceramic, carbon fiber, composites, and others.

Components of a clasp assembly may be made from any appropriate material, such as metal, plastic, wood, ceramic, carbon fiber, composites, and others. Various components of a clasp assembly may be made from different materials.

Components of a clasp assembly may be made using any appropriate construction techniques, such as cast, milled, molded, 3D printed, forged, stamped, laser cut, and others. Various components of a clasp assembly may be made using different construction techniques.

The internally threaded cylindrical hole and externally threaded cylindrical rod mating counterparts may be fixed to either a clasp component or a chape of a clasp assembly as the design dictates. The length of the threaded counterparts may be determined based on a clasp assembly's design and desired length adjustment range. The threads may be course or fine to provide the desired adjustability.

Friction between the clasp component's and chape's threaded components may be enhanced to prevent unintentional adjustments. To achieve this, the threads may have tight tolerances, they may have a friction-enhancing coating, they may be knurled, a friction-enhancing insert may be used in the internally threaded cylindrical hole, or other appropriate methods may be used.

A friction-enhancing insert would deform elastically over the threads of the externally threaded cylindrical rod to create a radial compressive force. It may be a collar, ring, bushing, sleeve, lining, or other appropriate type of insert, and it may be made from any appropriate material, such as plastic, nylon, rubber, silicon, and others.

These embodiments show how a length adjustable clasp assembly comprising a chape and a clasp component that are threaded together can provide a simple and easy adjustment of the fastened length of the clasp assembly and strap for an improved fit.

Although example embodiments are described in detail here, it should be appreciated that other versions and methods of use are possible. The provided figures and examples are for purposes of illustration, and should not be construed as limitations on the scope. Various modifications will be obvious to those skilled in the art, including variations in shape, size, assembly, and clasp operation, and are deemed equivalent to those illustrated and described.