Patent Application
20080148535
This invention relates to clips that secure to objects by elastic deformation of their structure, and more-particularly to biased-hinge clips.
Spring-loaded clips are used to join a variety of items to other structures. A commonly-used spring-loaded clip is the ordinary clothespin. This type of clip employs a wound metal spring to bias a pair of wooden or plastic jaw members together so as to apply frictional holding force to an object of clothing. While a separate spring member (constructed from a dissimilar material to that of the jaws) is common, other types of clips integrate a unitary spring into their construction.
One type of clip with a unitary (e.g. molded/formed as a single unit) clip design is the biased hinge clip. An example of a biased-hinge clip is taught in U.S. Pat. No. 3,720,979, entitled BIASED HINGES, by Krawagna. The clip is constructed using a pair of jaw members connected by a resilient hinge link that is sometimes termed a “living hinge,” in that it is a unitary part that joins the two hinged members together. Often the living hinge is defined by a narrowed region between two thicker parts that affords a degree of flexibility to the hinge section, while the attached members remain more rigid.
In the exemplary clip, the jaw members are each attached along their sides to opposing resilient hinge joints that interconnect with a semicircular spring base. The spring base allows the two jaws to rotate between a fully closed and a fully opened orientation. As the jaws open or close, the spring force bearing upon the jaws is overcome by the lever action of the jaws about the hinges. This causes the base to flex so as to absorb the hinging motion. The spring bias on the jaws forces then into either a fully opened or fully closed state. In the fully-closed state, the jaws maintain a predetermined pressure against each other so as to frictionally retain an object placed therebetween.
Such biased hinges are sometimes referred to as snap-hinges-due to the distinctive click that is heard and felt when the hinge locks or unlocks. These hinges have been employed in a variety of applications, such as clips used to hold X-ray and camera film. These clips are characterized by a pair of clamping jaws and an opposing hanging hook attached to the spring base.
In a number of industries, and particularly in the field of automotive upholstery, resilient clips are used commonly to secure upholstery to the foam cushion substrate. A seat is commonly constructed from at least three parts, (a) the underlying seat frame, which is often constructed from metal steel tubes formed into the outline of the seat, (b) a cushion that overlies the frame and is secured to the tubular frame, and (c) a n outer upholster layer or “skin” that wraps around the cushion and is secured to the frame. This skin often includes various pleats that conform to valleys molded into the cushion, providing the cushion with a more contoured and stylish look. Clips are often embedded in the foam at these valley locations during the molding process so that a bead on the upholstery seam can be subsequently snapped in place to create a characteristic pleat in the upholstered seat cushion. This system affords significantly quicker assembly and requires less skill that the earlier technique in which pleats were formed by applying metal rings between an anchor on the cushion and the upholstery. In addition the newer clip-down technique provides the installer with at least a small degree of tactile and auditory feedback when he or she has successfully secured a bead section to a clip—as evidenced by a noticeable “click.”
Nevertheless, the actual foam cushion is attached to the underlying tubular seat frame using more time consuming techniques that require proper alignment and the application of glues and adhesives to secure the foam to the frame tube. The adhesive process often forms a weak joint that is prone to detachment after the seat has been in use. Once detached, the cushion tends to dislocate, forming bulges in the upholstered seat. A technique that would allow this operation to be expedited, simplified and to provide better feedback of success is desirable.
Moreover, there are many other applications in which the ability to quickly and easily attach a base to a tubular member of a known, approximate cross sectional shape and size is desirable.
This invention overcomes disadvantages of the prior art by providing a clip for joining tubular members that employs living hinges that are part of a unitary clip including jaws and a base spring. The jaws are joined by a center living hinge and each jaw is also joined along a surface opposite its gripping surface to a cantilevered end of the base spring by a side-mounted living hinge. When the clip jaws are in a fully open orientation, with the center hinge at a maximum distance away from the base spring, the user biases the central hinge toward the base spring. The base spring ends are thereby biased away from each other under elastic deformation, and after the jaws rotate about their living hinges through a position of maximum spread in the base spring ends, the spring ends rebound, forcing the jaws downward toward the base spring, and into a fully closed orientation. Where a member is brought into contact with the center living hinge, it causes the jaws to close around it, resulting in an automatically closing clip. Once closed, the jaws retain the member against subsequent pullout. The clip includes a base attached to the spring base that is particularly adapted for a desired purpose. Thus, the base can be an anchor that embeds in foam of an upholstery cushion. In such an implementation, the cushion is attached to a tubular seat frame using the clips to snap it in place. The base can have an adhesive that allows it to be secured to a structure, in the case of a pipe or conduit clamp. The base can support a second clip of a predetermined size and shape. The second clip can be permanently mounted or attached by a fastener that allows the orientation of the two attached clips to be varied.
In an illustrative embodiment, the base spring and the jaws can be provided with interengaging hooks that lock the structure together in the fully closed orientation. Alternatively, a hook assembly can be arranged between the opposing jaw ends so that the fully closed position biases the hook ends into engagement for permanent locking. The clip can be formed by extrusion, with the hinges optionally coextruded from a more-resilient material. The extrusion can define a strip with cut lines therein that nearly separate the individual clip segments. The remaining material therebetween (typically along adjoining bases) allows the clip segments to bend with respect to each other, thereby enabling the clip strip to be stored on a spool and paid out as needed. An automated process can be employed in which clips are paid out to a manipulator that cuts clip segments from the end of a roll, grasps them, and deposits them in a desired location, such as a foam cushion mold cavity.
The clip can include a grasping surface on its jaws that is serrated to enhance grasping friction against soft-sided members. Alternatively, the clip can include a high-friction surface that is applied or coextruded onto the jaws. This material facilitates grasping of objects with smooth surfaces and/or slightly larger/smaller/irregular shapes relative to the jaws.
The invention description below refers to the accompanying drawings, of which:
The jaws are joined along a longitudinal centerline at a hinge 120. The hinge 120 defines a living hinge with a thinned region of the overall jaw structure, and is formed unitarily with the jaws 110. The hinge may be constructed from a dissimilar material (a more resilient plastic, for example) relative to the jaw material (a more rigid plastic, for example). Flexibility is further provided by defining the hinge thickness TCH to be narrower that the jaw thickness TJ. For example, where the jaw thickness is between approximately 2 and 4 millimeters, the hinge thickness is 0.3-0.7 millimeters. These dimensions are exemplary and adapted toward a clip with a jaw radius RJ of between 1 and 5 centimeters. These relationships are highly variable, depending in part upon the materials employed in the clip and its hinges.
The jaws 110 are each joined along their respective opposing outer surface to a semicircular spring base 130. Each hinge joint 132 is a narrowed region that joins the opposing, cantilevered ends 134 of the spring base 130 to locations along the outer surface 136 of each jaw 110. The thickness of the hinge joint 132 can have a thickness THJ similar to that of the center hinge 120 so as to define a flexible, living hinge between the spring base 130 and the respective jaws 110. In this embodiment, the spring base defines a semicircular cross sectional shape as shown. This shape corresponds approximately to the shape of the jar outer surfaces in the region between the hinges 132. The thickness TS of the spring is highly variable. In the above example, the thickness is between approximately 2 and 4 millimeters. The thickness of both the jaws 110 and the spring base 130 can be constant or variable along their respective surfaces to achieve desired effects.
The spring base 130 is joined to a base plate 140 at the bottom of the spring base 130. The base plate 140 herein is shown as a rectangle. As described below, the base plate can be any acceptable shape.
As shown now in
Referring now to
In
In the fully closed orientation of
Before describing various alternate embodiments of the clip and methods of manufacture, the foregoing description may be summarized as follows: The clip employs living hinges that are part of a unitary clip structure including jaws and a base spring. The jaws are joined by a center living hinge, and each jaw is also joined along a surface opposite its gripping surface to a cantilevered end of the base spring by a side-mounted living hinge. When the clip jaws are in a fully open orientation, with the center hinge at a maximum distance away from the base spring, the user biases the central hinge toward the base spring. The base spring ends are thereby biased away from each other under elastic deformation, and after the jaws rotate about their living hinges through a position of maximum spread in the base spring ends, the spring ends rebound, forcing the jaws downward toward the base spring, and into a fully closed orientation. Where a member is brought into contact with the center living hinge, it causes the jaws to close around it, resulting in an automatically closing clip.
The clip of this invention can be constructed in a variety of manners, using a variety of commercially available materials. Referring to
A strip of continuous clips can be formed using a variety of techniques including molding and casting. In an illustrative embodiment, well-known extrusion processes are employed, whereby a selected material in a formable solid or liquid state is passed under pressure through a die (or dies) having a respective cavity that matches the outline/cross section shape of the strip 610. As the strip exits the extrusion device (not shown), a blade provides the illustrative cut lines 630 at desired intervals. The blade, or another cutter, can fully cut off a strip end when a strip of desired length has been completed. As discussed above, it is often desirable to provide particular properties to the clip so as to facilitate strength, long-live, flexibility and/or adhesion to other materials (foam, for example). Often, it is desirable to provide rigidity and durability to the jaws, resilience to the hinges, flexibility to the spring base and adhesive properties to the base plate. This mix of properties within a single strip can be attained through well-known coextrusion techniques. In the depicted strip 610, the regions that contain the hinges 120 and 132 have been coextruded in more-resilient, elastic material, such as a flexible TPE—as indicated by shaded areas 650—while the surrounding unitary material is a more rugged/rigid material such as polycarbonate. It should be clear that a wide range of possible coextruded materials can be incorporated into the clip. In additions, the formation process may take advantage of certain physical properties within the chosen, coextruded material to increase fatigue life. It is know that flexing the material (for example, polyethylene, polypropylene and nylon) while warm serves to realign the polymer chains so as to provide the hinge material with the ability to withstand many more-thousands of cycles than an untreated material.
A notable advantage to the use of biased hinge/living hinge clips as shown herein is that, in an opened orientation, these clips exhibit a lower profile that a traditional clip. These clips also resist compression forces better. Hence, when installed in substrates that undergo compression forces during manufacture, the clips of this invention are more likely to escape damage.
As described above, the formation of clips on a long, continuous strip facilitates the installation of clips in an automated environment.
Referring to
Notably, the external surface 836 of each jaw 810 carries a hook-like projection 850. Each projection 850 contains a protuberance 852 that is adapted to interengage an opposing protuberance 854 on a hook-like projection 856 located on the facing side 860 of the spring base 830. The projections 850, 856 are aligned so that the protuberances 852, 854 cause mutual elastic deformation of the projections as the protuberances pass by each other when the jaws 810 are biased into the fully closed orientation. This locked position is shown in
An alternate locking mechanism is shown in
Referring now to the exemplary clip 1100 of
The internal surface of the clip can be textured or serrated to increase the grip relative to certain types of surfaces.
In
The clip base can be adapted to allow for a variety of applications other than upholstery. As shown in
In
In this embodiment, grooves 1450 that extend along the full longitudinal direction of the base 1440 are employed as these are readily formed by extrusion processes. In alternate embodiments, the base 1440 can be provided with holes or discrete wells (countersunk formations) that can be formed using alternate, post-extrusion processes, such as punching or drilling.
As described above, the clip base can vary widely in structure and function. As shown in
As described above, the clips of this embodiment can be formed as a strip with cut lines at predetermined spacings. These cut lines nearly sever the clips, but remain joined along a portion of the interconnected bases. The partial cut in each base affords a degree of flexibility between clip segments—and the clips are capable of rotating about the cut lines within a predetermined range of motion. As shown in
It should be clear that the above embodiment provide a clip that is sturdy, easy to deploy, versatile and formed by a number of readily available mass-production processes. The clip can be provided in a manner that facilitates automation of installation in a number of industries.
The foregoing has been a detailed description of illustrative embodiments of the invention. Various modifications and additions can be made without departing from the spirit and scope if this invention. Each of the various embodiments described above may be combined with other described embodiments in order to provide multiple features. Furthermore, while the foregoing describes a number of separate embodiments of the apparatus and method of the present invention, what has been described herein is merely illustrative of the application of the principles of the present invention. For example, The inner surface of the jaws can be provided with a resilient layer that improves frictional grip on the gripped member and allows for variation in the size of the member relative to a specific size of clip (since the layer compresses more to conform to slightly larger-diameter members). In addition, the thin interconnection between the base plates on separated clips in a strip can be provided with through-cut perforations along the adjoining base plates to facilitate easier separation by hand or machine. Also, the clip can be enlarged and adapted to secure large items, such as sewer pipes. Anchor bases for such clips (and others) can be adapted to secure into earth, gravel or concrete. Other bases can allow the clip to be employed as part of a modular system, including rack systems, structured wiring panels and tool holders. Where the clip is used for holding tools and other items that may require repeated open/close cycles, appropriate frictional surfaces can be applied to the jaws where needed, and the jaws can be provided with tabs that facilitate the opening and release of the jaws. Also, while a roll of clips that are nearly separated except of a line of material at the base are shown, the material joining the clip segments can be located at another position, such as the jaw ends (with bases fully separated). Alternatively, the clip strip may be stored on a roll and/or paid out to a utilization device in an unseparated form where the strip is sufficiently flexible and/or the wind on the roll is sufficient large in radius. The utilization device would then slice off each clip from the strip to an appropriate length (possibly a variable length). Accordingly, this description is meant to be taken only by way of example, and not to otherwise limit the scope of this invention.
