Desk chair mat
A desk chair mat has a substantially planar upper surface suitable for interaction with a chair support structure, a perimeter defining an outer edge of the mat, a lower surface parallel to the upper surface. An array of generally blunt ended and laterally elongated projections extends downwardly from the lower surface for engagement with a carpet. A decorative pattern is also formed on the lower surface that is visible through the upper surface. Each projection has a smooth end surface spaced below the lower surface by a distance sufficient to penetrate into the carpet pile. The array is generally a regular pattern of the projections that can be arranged at an angle with respect to each nearest neighbor to provide enhanced resistance to lateral movement of the mat with respect to the carpet to protect the decorative pattern from abrasion.
The present invention is a continuation-in-part of U.S. application Ser. No. 10/842,387 filed May 10, 2004, which is in turn a continuation-in-part of U.S. application Ser. No. 10/439,691 filed May 16, 2003.
BACKGROUNDThe present invention is directed to chair mats and specifically, to chair mats typically used under desk chairs in order to protect an underlying carpet. In particular, the present invention relates to a chair mat having a decorative pattern and on which a chair, such as a desk chair, may be used without harming the decorative pattern.
Desk chair mats for office and home use are well known. Such a chair mat has a main portion on which the desk chair rolls, and can include a forward lip portion which is adapted to extend partially into a desk well, and on which the feet of the person sitting in the chair can rest. A desk chair mat that is to be applied over carpeting is typically formed of a semi-rigid plastic, and has an array of short, sharp spikes on an underside thereof, which hold the mat firmly in place on the carpeting. While desk chair mats can be made without any spikes, the mats tend to move relative to the carpet in response to movement of any desk chair on the top surface of the mat. Thus a carpet-engaging structure is deemed necessary to achieve satisfactory performance.
Such a desk chair mat is awkward to carry and/or otherwise handle due to its size, the semi-rigid nature of the material from which it is formed, and particularly with the spikes. Unless the chair mat is boxed or otherwise protected, the user typically carries the chair mat by gripping about one or two of the edges of the chair mat, often resulting in irritation if not injury to the hands, due to the spikes projecting from the underside of the chair mat.
Attempts have been made to solve these problems by making the chair mat foldable to thereby reduce its size for handling purposes. See, for example, U.S. Pat. Nos. 4,784,888; 5,073,428 6,183,833 and 6,284,341. Further, handles have been included as a portion of the chair mat to enable safe handling. See, for example, U.S. Pat. Nos. 6,177,165; 6,287,659 and 6,308,842. Generally, desk chair mats have been sold at office supply stores or distributors as opposed to retail stores, and to some extent, the handling problem was alleviated by boxing the chair mats individually or in groups prior to shipping. Chair mats are now being found increasingly in retail outlets, compounding the problem of safe handling. While chair mats can be boxed, the boxes add cost and are themselves unwieldy, and are therefore not necessarily desirable in the retail environment. Thus, with increasing retail activity, new display schemes are also required. The last mentioned patent includes the disclosure of a retail display system designed to facilitate safer handling of chair mats.
Even when supplied from a distributor in boxed form, the end user must remove the chair mat from the box and position it at its final destination, again, with some difficulty due to the physical attributes of the chair mat. Thus the opportunity for irritation if not injury to the hands, due to the spikes projecting from the underside of the chair mat continues even after purchase. Accordingly, there remains a need for a solution to the problem of transporting desk chair mats easily and safely from the point of manufacture through the point of stocking and display in a retail environment to the point of ultimate use.
Once situated for use, a typical chair mat tends to be positioned over carpeting. Such chair mats are typically made of a transparent or translucent plastic material. Thus, the underlying carpet on which the chair mat is placed is visible through the chair mat as are the structural details of the pattern of spikes that project down to engage the carpet. The chair mat generally does not make any separate esthetic contribution. Some attempts have been made to arrive at chair mats that contribute esthetically as well as provide protection for the underlying carpet, for example, the mat disclosed in U.S. Pat. No. 6,319,592 to Ney et al. The Ney mat consisted of a separately prepared graphics layer sandwiched between a rigid base layer and a rigid upper protective layer. Both the base layer and upper protective layer were bonded to the graphics layer with the aid of adhesives. The nature of the graphics layer or the underlying adhesives layer is such as to render the base layer invisible. The area of the carpeting under such a chair mat would also be rendered invisible. This has the effect of making the chair mat itself stand out from the remaining portion of the carpeting, which may not be desirable in many situations.
Accordingly, there remains a need for a desk chair mat that includes a decorative contribution that is not subject to surface wear and remains visible along with the underlying carpet. There is also a need for such a desk chair mat that includes a carpet engaging structure that is designed for safe handling. It is desirable that these features be incorporated in a single structure having other features that contribute to easy handling and reduced cost
BRIEF SUMMARYA desk chair mat of the present invention is intended for interposition between a carpet upper surface and a chair, and can have a substantially planar upper surface suitable for interaction with a chair support structure that typically includes a plurality of wheels on the lower outside points of a spider. The desk chair mat has a perimeter defining an outer edge of the mat, and a lower surface parallel to the upper surface. The lower surface can include an array of blunt projections extending downwardly from the lower surface for engagement with the carpet. Each of the projections can have a smooth end surface spaced below the lower surface of the desk chair mat by a distance sufficient to penetrate into the carpet upper surface, typically by about 3 mm or more. The array of projections can be confined to a one or more selected areas of the lower surface. The array of projections can be distributed substantially continuously over the entirety of the lower surface. The array of projections resists lateral forces acting on the desk chair mat and thereby stabilizes the mat with respect to the carpet.
The array of blunt projections can assume any number of appearances. The blunt projections can be linear, angular or curved. The vertical cross-sectional aspect ratio of the blunt projections is greater that one in a first direction and less than one in a direction normal to the first direction so that the blunt projections are laterally elongated. The smooth end surfaces of the blunt projections can be generally parallel to the lower surface of the desk chair mat or arcuate. The smooth end surface of each of the blunt projections has an area sufficient to prevent penetration of the skin of someone handling the mat, which is believed to be at least about 8 mm2. The end surface of each of the blunt projections is sufficiently smooth to prevent abrasion of the skin of someone handling the mat.
The blunt projections can be aligned in spaced linear arrays. The resistance to lateral forces can be enhanced by arranging the blunt projections in a regular pattern wherein each projection is situated at an angle with respect to each nearest neighbor. The resistance to lateral forces can also be achieved by arranging the blunt projections in rows with the projections in adjacent rows being situated at an angle to each other. The blunt projections can cover a majority of the lower surface of the desk chair mat, but need not extend to any given area including the perimeter. The distance between the blunt projections can vary considerably, but is typically between about 1 and 4 cm.
A desk chair mat of the present invention is preferably sufficiently transparent that any pattern in the underlying carpet is not hidden or concealed by the presence of the desk chair mat. The array of blunt projections can be incorporated into other decorative designs present on the lower surface of the desk chair mat that are also visible through the substantially transparent mat. The other decorative designs can be, for example, in the form of ridges connecting the blunt projections or islands surrounding the blunt projections. The decorative designs can include undulating or other periodic surface variations on the lower surface of the desk chair mat that are formed by modest regular variations in the thickness of the mat. The variations on the lower surface of the chair mat can be formed during the extrusion-fabrication process by including an embossed or etched pattern on a pattern roll that is brought into intimate contact with the lower surface of the mat.
A desk chair mat of the present invention can be made from a suitable semi-rigid substantially transparent plastic such as acrylic, polycarbonate, polypropylene, or polyvinylchloride. The plastic preferably has a Rockwell hardness of between about 80 and 95, and can include static-reducing elements so long as the presence of such static-reducing elements will not significantly reduce the transparency of the mat. A desk chair mat of the present invention can include handles and tab structures that will facilitate the handling and display of the mat. A desk chair mat of the present invention can also include one or more fold lines or cuts that will enhance ease of handling. A graphic can also be included, for example, by contacting a second selected area of the chair mat lower or upper surface with a silk screen mat, a print transfer roll, a label, a decal, or other indicia bearing sheet or transfer roll. The first surface can remain un-affected by the application of the graphic so that the chair mat is generally transparent except where the subject matter of the graphic sufficiently inhibits the view of the underlying carpet.
One advantage of a desk chair mat of the present invention is a reduction in damage to the underlying carpet since the characteristic feature of the smooth end structure of the blunt projections that inhibits irritation and injury to the hands also protects the carpet. Another advantage of a desk chair mat of the present invention is a desk chair mat that can be produced at comparatively low cost yet can contain attractive decorative features on the lower surface of the mat that are protected from wear and visible through the substantially transparent mat. Other features and advantages of a desk chair mat of the present invention will become apparent to those skilled in the art from a consideration of the following discussion that makes reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
An upper surface 32 of the chair mat 10 is generally smooth, as shown in
The laterally elongated, blunt ended projections 46 can include a smooth end surface 50 spaced below the lower surface 44 by about 3 to 10 mm. In cross-section, as seen in
Some typical laterally elongated, blunt ended projections 46 on lower surfaces 42 of a chair mat 10 of the present invention are shown in greater detail in
The laterally elongated, blunt ended projections 46 can be arranged in a variety of patterns. Further the projections 46 can take a variety of individual shapes. Both
A variation on this rectangular array is shown in
A further variation on this rectangular array is shown in
The arrays of the projections 46 need not be rectangular. For example, in
One convenient method for manufacturing the mats 10 of the present invention is illustrated schematically in
A take-off roller 198 is positioned below the main roller 196 to ensure that the extruded plastic web 195 is retained in contact with the surface 197 of the main roller 196 for sufficient time to “freeze” the features of the projections 46 and decorative features 49 into the plastic of the chair mat 10. The take-off roller 198 can also be used in conjunction with an application roller 200 and an ink roller 202 to apply an optional printed graphic image to the bottom surface 44 of the web 195. The take-off roller 198 can also be used in conjunction with application roller 200 to apply a label or decal 201 from a supply roller 204 to the bottom surface 44 of the web 195. The take-off roller 198 can also direct the extruded plastic web 195 through a nip 206 between cutting rollers 208 and 210 that can be used to separate the chair mats 10 from each other and from any waste portion 199 of the web 195. The position of the cutting rollers 208 and 210 with respect to the various areas containing, respectively, the projections 46 and decorative features 49 can be controlled by a synchronizing means 212 such as a timing belt or an optical sensor and control. The desk pads 10 can then be conveyed by conveyor 214 for additional processing and packaging, if desired.
The foregoing detailed description should be regarded as illustrative rather than limiting, and the following claims, including all equivalents, define the spirit and scope of this invention.
Claims
1. A desk chair mat for interposition between a carpet and a chair, the desk chair mat comprising: a substantially transparent body having a generally planar upper surface suitable for interaction with a chair support structure, a perimeter defining an outer edge of the body, and a lower surface generally parallel to the upper surface, the lower surface including a decorative pattern that is visible through the upper surface and an array of laterally elongated projections having blunt and smooth end surfaces extending downwardly for engagement with any underlying carpet.
2. The desk chair mat of claim 1 wherein the smooth end surface of each of the projections is generally parallel to the lower surface.
3. The desk chair mat of claim 1 wherein a horizontal cross-sectional aspect ratio of each of the projections is between about 2 and 4.
4. The desk chair mat of claim 1 wherein the smooth end surface of each of the projections has an area of at least about 8 mm2.
5. The desk chair mat of claim 1 wherein the smooth end surface of each of the projections is spaced from the lower surface by about 3 to 10 mm.
6. The desk chair mat of claim 1 wherein the projections are arrayed such that each projection is spaced from its nearest neighbor projection by between about 1 and 4 cm.
7. The desk chair mat of claim 1 wherein a vertical cross-sectional aspect ratio of the projections is greater than one in a first direction and less than one in a second direction.
8. The desk chair mat of claim 1 wherein the array comprises a regular pattern of projections arranged at an angle with respect to each nearest neighbor.
9. The desk chair mat of claim 8 wherein the angle is at least 300.
10. The desk chair mat of claim 1 wherein some of the projections are connected to each other with ridges that extend from the bottom surface by a distance less than the blunt projections.
11. The desk chair mat of claim 1 wherein the decorative pattern extends continuously over the entire lower surface.
12. The desk chair mat of claim 1 wherein the decorative pattern extends over only a selected portion of the lower surface.
13. The desk chair mat of claim 1 further comprising at least one opening within said perimeter forming a handle for the mat.
14. A desk chair mat for interposition between a carpet and a chair, the desk chair mat comprising: a semi-rigid sheet of plastic having a substantially planar upper surface suitable for interaction with a chair support structure, a perimeter defining an outer edge of the mat, a lower surface parallel to the upper surface, the lower surface including a decorative pattern that is visible through the upper surface and an array of laterally elongated, blunt ended projections extending downwardly from the lower surface for engagement with any underlying carpet, each projection having a smooth end surface spaced below the lower surface by a distance sufficient to penetrate into the carpet, the array being a regular pattern of the blunt projections arranged at an angle with respect to each nearest neighbor to provide resistance to any lateral movement of the mat with respect to the carpet.
15. A method of manufacturing a desk chair mat for interposition between a carpet and a desk chair, the method comprising the steps of:
- providing a first roll having a surface including an array of cavities,
- coupling the first roll to a second roll to define a nip of selected dimension,
- extruding a stream of plastic into the nip under conditions ensuring that the array of cavities will be generally filled by the plastic to form a decorative pattern that is visible through the upper surface and an array of laterally extending, blunt ended projections on a first surface of a continuous web of plastic,
- defining a perimeter of a mat surrounding the first and second areas of the continuous web, and
- separating the mat within the perimeter from the continuous web.
16. The method of claim 15 further comprising a step of creating a graphic image on the surface of the first roll.
17. The method of claim 15 further comprising a step of creating a graphic image on the mat by printing the image on a surface of the continuous web.
18. The method of claim 15 further comprising the steps of creating a graphic image on a separately formed web and bonding the separately formed image to a surface of the continuous web.
19. The method of claim 15 further comprising the step of shaping the interior of the cavities to have a smooth truncated end surface capable of molding the smooth blunt ended projections.
20. A desk chair mat for interposition between a carpet and a chair, the desk chair mat comprising: a semi-rigid sheet of plastic having a substantially planar upper surface suitable for interaction with a chair support structure, a perimeter defining an outer edge of the mat, a lower surface parallel to the upper surface, the lower surface including a three-dimension decorative pattern that is visible through the upper surface, the decorative pattern including sufficient vertical relief to comprise an array of laterally elongated, blunt ended projections extending downwardly from the lower surface for engagement with any underlying carpet.
Type: Application
Filed: Sep 20, 2004
Publication Date: Feb 17, 2005
Inventor: Edward Robbins (Muscle Shoals, AL)
Application Number: 10/945,169