Patent Application
20050034585
The present invention relates to devices for cutting sheet material, and more particularly to a new and useful shearing device adapted for use in combination with guided cutting assemblies which enhances safety, facilitates low cost manufacture, produces a clean, even and reliable cut, while maintaining a low profile geometry for integration with a dispensing container.
Various cutting devices and assemblies are employed for cutting strips or sheets of web material from a dispensing container. Most familiar and frequently used are cutting assemblies for dispensing household products such as plastic wraps, metal foils and waxed papers, etc. Typically these products are disposed/sold in an elongate box and cut by means of a serrated cutter along an edge of the box to cut/separate the material into desired lengths for use. To dispense the material, the consumer holds an end of the material in one hand and the box dispenser in the other, pulls the two apart applying tension to the material, and rotates or otherwise orients the box so as to cause the serrated cutter to grab and cut the material. While box dispensers which employ serrated cutters of this type have and are still widely used for dispensing such materials, most consumers are familiar with (and tolerate) the various drawbacks and difficulties of such dispensing devices. For example, the application of tension and inefficiency of the serrated cutter may cause recoil or spring-back of the material (upon itself) requiring cumbersome separation/straightening of the material (into a flat sheet). The tendency for the material to spring back and fold upon itself may be even more problematic in materials having resilient properties (i.e. a low elastic modulus) such as plastic wraps.
Other difficulties relate to the inability for such serrated cutters to produce a clean, even cut, i.e., parallel to the axis of the webbed material. It will be appreciated that the serrated blades, which essentially puncture the material to create aligned perforations, produce a rough or tattered edge. While shaper blades produce a cleaner cut, such blades may be hazardous inasmuch as the blades are typically mounted to an edge of the container and are exposed.
Other cutting devices employ blades attached to and slideable within a guide track. The web material is dispensed, laid across the track, and cut by passing the cutting blade edgewise through the material. While these cutting devices produce a clean, even cut, the track and cutting blade typically protrude well beyond the exterior of the dispensing container thereby producing an unstreamlined external geometry. Aside from aesthetic drawbacks, the cutting device produces difficulties storing, packaging and stacking the dispensing containers. Further, inasmuch as the web material may not be tensioned during the cutting operation, the cutting blades employed are often highly sharpened to produce a clean cut. Such blades are most practically and conventionally formed by a metal alloy material which can be hardened (carburized) along the blade edge to improve the efficacy and durability of the blade. Drawbacks, however, to the use of metal cutting blades relate to the comparatively high fabrication costs relative to other potential material substitutes e.g., thermoplastics, which may be shaped utilizing lower cost manufacturing methods, e.g., casting, molding etc. Of course, material properties which are advantageous for the purpose of forming/shaping a material are typically dichotomous to properties which improve the yield strength and durability of a material. Consequently, the cutting blades for use in these applications are typically composed of metal and higher fabrication costs are accepted to achieve the desired hardness.
A need, therefore, exists for a cutting device which provides enhances operator safety, facilitates low cost manufacture, produces a clean even and reliable cut, while maintaining a low profile geometry for integration with a dispensing container.
A shearing device adapted for use within a cutting assembly operative to guide and delimit the motion/displacement of the shearing blade as the shearing device traverses in a desired cutting direction. The shearing device includes at least one pair of cutting blades wherein each of the cutting blades defines a least one edge which is inclined relative to the cutting direction. Furthermore, the blades are juxtaposed such that the inclined edges spatially converge to define a throat region and a convergence point. To maintain the spatial position of the cutting blades, a connecting means is disposed between the cutting blades. Further, a bearing support structure is disposed in combination with at least one of the cutting blades and engages the guide of the cutting assembly. Moreover, a handle is disposed in combination with at least one of the cutting blades and is adapted for traversing the cutting blades in the cutting assembly guide.
For the purpose of illustrating the invention, there is shown in the drawings various forms that are presently preferred; it being understood, however, that this invention is not limited to the precise arrangements and constructions particularly shown.
a is a broken away cross sectional view taken substantially along line 2a-2a of
b is a cross sectional view taken substantially along line 2b-2b of
a is an isolated plan view of the shearing device including a pair of cutting blades in juxtaposed relation and having edges which, in combination, converge to define a substantially V-shaped geometric profile.
b is a cross sectional view taken substantially along line 3b-3b of
c is an isolated view of a preferred embodiment of the shearing device wherein the blades are integrally formed and fold about a hinge to juxtaposition the cutting blades.
d is a cross sectional view taken substantially along line 3d-3d of
A shearing device is described for use in combination with a guided cutting assembly. Cutting assemblies of the type described are useful for dispensing a web of material, or sheet material from rolled material stock and cutting the web material to a desired length.
Referring now to the figures wherein reference numerals identify like elements, components, subassemblies etc., of the invention,
In
Before describing the specific geometry and/or structural elements of the shearing device 10, it will be useful to generally discuss the function and interaction of the shearing device 10 with other cutting assembly or dispenser components. In
Referring now to
In the described embodiment, the cutting edge portions 38a(1), 38b(1) define a substantially V-shaped geometric profile wherein the convengence point P is the vertex of two intersecting lines i.e., defined by each of the inclined cutting edges 38a(1), 38b(1). In the context used herein, substantially V-shaped means any two cutting edges which converge at a point and define a throat characterized by decreased edge spacing, (transverse to the cutting direction), as the web material 20 is introduced to the cutting blades 30a, 30b. It should be understood however, that the cutting edges 38a(1), 38b(1) may have a different geometric shape, e.g., two substantially convex or concave-shaped cutting edges defining a cycloid, while still meeting definition of a V-shaped geometric profile.
In the red embodiment, both of the cutting edges 38a(1), 38b(1) are sharpened, however, a single cutting edge 38a(1) or 38b(1) may be employed to reduce processing steps and/or manufacturing costs. That is, the cutting edges 38a(1), 38b(1) will still perform their intended function with only a single sharpened edge. Furthermore, the cutting edges 38a(1), 38b(1), 38a(2), 38b(2) are preferably formed on both sides of the cutting blades 30a, 30b i.e., along oppositely disposed ends of the blade to facilitate bi-directional cutting operations.
The connecting means 34 maintains the spatial relationship of the cutting blades during cutting operations, i.e., either in one or both cutting directions DC, but may include any of a variety of connecting methods or devices. In the preferred embodiment, the connecting means is a hinge 44 integrally formed along an edge of the cutting blades 30a, 30b. As such, the shearing device 10 may be formed, manufactured or molded as a unit and folded about the hinge 44 to juxtaposition the cutting blades 30a, 30b. In the described embodiment, an effective hinge 44 is produced by reducing the material thickness at a point along the lower edges of the cutting blades 30a, 30b. Alternatively, a mechanical interlock assembly (not shown) may be employed having a male member integrally formed and protruding from a side of one of the cutting blades, and a female member having an orifice integrally formed within a side of the other of the cutting blades for accepting the male member. The teachings described herein are readily implementable to those skilled in the art and it will be appreciated that a variety of other connecting means can be envisioned.
While the cutting blades 30a, 30b may be composed of a variety of material compositions, it is preferable to compose the shearing device from a formable polymer, e.g., a thermoplastic or other plastic material. As such, the cutting blades 30a, 30b may be fabricated by a low cost injection molding process. The embodiment which includes the hinged connecting means 34, i.e., wherein the shearing device 10 is a singular unit, is particularly well suited to such molding process.
The bearing support member 36 is preferably configured in the shape of a rectangular key 50 upon which is formed the bearing surfaces 28 of the shearing device 10. The key 50 is adapted for slideably engaging a similarly shaped guide surface 24 of the cutting assembly 14. Moreover, in the preferred embodiment, a key 50 is disposed on each of the cutting blades 30a, 30b and defines a substantially T-shaped cross sectional configuration. The guide 12, therefore, also has a complimentary T-shaped cross section.
To improve the profile geometry of the shearing device 10 yet further and prior to use, it may be desirable to incorporate design features which facilitate assembly/disassembly of the shearing device 10 relative to the guide 12. That is, to facilitate packaging/shipping/store display, the guide 12 may be integrated with the container 16 as described and illustrated herein (i.e., recessed and proximal to a corner of the container), however, the shearing device 10 may be provided as a separate component for subsequent assembly/installation. Regarding the latter, an aperture or enlarged opening (not shown) is provided in the guide 12 to facilitate receipt and installation of the shearing device 10 within the guide 12. Alternatively, the guide and bearing surfaces 24, 28 may be resilient to permit a small degree of flexure, thereby enabling the guide surfaces 28 to move apart when introducing the shearing device 10 into the guide 12.
In operation, and referring collectively to
In
While the invention is described in the context of a guided cutting assembly used in combination with a conventional elongate cardboard container, it should be understood that the inventive shearing device may be employed with any guided cutting assembly, or any dispenser, which may or may not dispense sheet material which has been rolled. Further, while the shearing device has particular application in small containers typically used to dispense household products such as plastic wraps, foils or paper, the shearing device has utility in more sophisticated commercial/industrial applications, for example for cutting a web of material in a manufacturing environment. The illustrated embodiments described herein depict the shearing device assembled in combination with a dispensing container. It should be understood, however, that the inventive shearing device may be provided as an independent element and installed/assembled with the guide or container subsequent to sale or delivery.
In summary, the structural and functional elements described herein provide the teachings necessary to design and fabricate a shearing device for use in cutting assemblies. The shearing device facilitates manufacture using low cost fabrication methods, e.g., injection molding of thermoplastic or other polymeric materials. Furthermore, the shearing action of the blades provides clean reliable cut without the requirement or need for highly sharpened edges. Additionally, product safety is improved. Finally, the shearing device provides a simple, pragmatic, low cost alternative to the cutting devices of the prior art.
A variety of modifications to the embodiments described will be apparent to those skilled in the art from the disclosure provided herein. Thus, the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof and, accordingly, reference should be made to the appended claims, rather than to the foregoing specification, as indicating the scope of the invention.
