Abstract:
A furniture glide base having a substantially circular sliding surface that is of elastomeric material, preferably a thermoplastic urethane such as polyurethane. In one embodiment, the glide base has an annular rim portion extending obliquely upward from the periphery of the circular sliding surface to a first elevation, and a central post extending vertically upward from the center of the base, to a higher elevation. The post can have an upper end that forms a spherical surface to form part of a swivel joint. In another embodiment, the base has an annular rim portion of the same or different material, extending upward from the periphery of the circular sliding surface, for receiving a furniture leg.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     The present invention relates to furniture glides, and more particularly to an improved furniture glide base.  
         [0002]     Furniture glides are available in a variety of styles and constructions, but an essential purpose is to provide an upper portion for receiving a furniture leg and a lower portion defining a sliding surface. U.S. Pat. No. 5,991,974, “Swivelling Furniture Glide”, and U.S. Pat. No. 6,154,923, “High Hold Furniture Glide”, and U.S. Publication US2002/0088082A1 describe glides of the type having a three main components: (1) a ferrule including a bottom wall, an upstanding cylindrical side wall extending from the bottom wall and defining a socket for receiving a furniture leg, and clip means within the socket, for engaging a received furniture leg, (2) a swivelable glide support shell affixed to the bottom wall of the ferrule, and (3) a glide base affixed to the support shell and defining a substantially flat sliding surface for contacting the floor.  
         [0003]     U.S. Pat. No. 6,405,982, “Self-Attaching Sliding Support for Articles of Furniture”, describes another type of glide that does not have a ferrule or swivel capability, but rather consists of a generally cup-shaped, unitary body of a resilient element for gripping the legs and an integrated slidable base element for contact with the floor.  
         [0004]     In these and other known furniture glides, the sliding surface for contacting the floor is of a material specifically chosen for its relatively high hardness. Typical base element materials include steel (usually selected for carpeted floors) or hard plastics such as nylon or polyethylene (typically selected for tile floors). These materials should ideally provide durability and easy cleaning of the sliding surface, and easy and quiet sliding of the furniture along the floor, without abrasion or smudging. Although these materials may perform satisfactorily under new or clean conditions, the presence of dirt and debris on the floor in real operating environments, considerably degrades the performance of furniture glides that utilize these base materials.  
       SUMMARY OF THE INVENTION  
       [0005]     It is an object of the present invention to provide a furniture glide having a sliding surface that can be used on both carpet and tile floors, and which maintains for extended periods of use, satisfactory durability and easy cleaning, and easy and quiet sliding along the floor, without abrasion or smudging.  
         [0006]     In a general aspect, the invention can be summarized as a furniture glide base having a substantially circular sliding surface that is of elastomeric material, preferably a thermoplastic urethane such as polyurethane. In one embodiment, the glide base has an annular rim portion extending obliquely upward from the periphery of the circular sliding surface to a first elevation, and a central post extending vertically upward from the center of the base, to a higher elevation. The post can have an upper end that forms a spherical surface to form part of a swivel joint. In another embodiment, the base has an annular rim portion of the same or different material, extending upward from the periphery of the circular sliding surface, for receiving a furniture leg.  
         [0007]     In another aspect, the invention is a furniture glide comprising an upper portion for receiving a furniture leg and a lower portion defining a smooth sliding surface, wherein the lower portion consists of an elastomeric material.  
         [0008]     In yet another aspect, the invention is directed to a glide for a furniture leg, comprising (1) a ferrule including a bottom wall, an upstanding cylindrical side wall extending from the bottom wall and defining a socket for receiving a furniture leg, and clip means within the socket, for engaging a received furniture leg, (2) a glide support shell affixed to the bottom wall of the ferrule, and (3) and a glide base affixed to the support shell and defining a substantially flat sliding surface, wherein the sliding surface is an elastomer.  
         [0009]     Regardless of the embodiment, the relatively soft sliding surface of elastomeric material according to the invention performs surprisingly well on all floor surfaces. It is believed that as a result of the weight load transferred through the furniture leg causing localized high-pressure contact of dirt and debris, such as sand, glass shards, metal chips and slivers and other hard particles, the softer surface yields to temporarily “absorb” the particles. As an example, when a student sits on a chair having glides according to the invention, the particles under the sliding surface are temporarily absorbed by (i.e., recede into) the base such that when the seated student shifts the chair under a desk or table or the like, the particles trapped in the sliding surface do not interfere with the inherently low-friction interface between the sliding surface and the floor.  
         [0010]     This absorption effect not only reduces the deleterious effect on sliding due to the presence of particles between the floor and sliding surface, but by the same mechanism reduces the abrasion and smudging of the floor that can arise as particles are “scraped” across a floor by the movement of furniture such as the shifting of a chair. Similarly, the scraping of the sliding surface by such particles is also reduced, thereby extending the life of what conventional thinking would consider unsuitably soft and vulnerable material for this end use.  
         [0011]     Another advantage of the invention, is that when the weight on the base is relieved, the deformations in the base material caused by absorption of the particles are restored, thereby pushing the absorbed particles to the sliding surface where they can be easily cleaned.  
         [0012]     Accordingly, it should be evident that the present invention readily achieves the objective of providing a furniture glide having a sliding surface that can be used on both carpet and tile floors, and which maintains for extended periods of use, satisfactory durability and easy cleaning, and easy and quiet sliding along the floor, without abrasion or smudging. 
     
    
     BRIEF DESCRIPTION OF THE DRAWING  
       [0013]     The preferred embodiments of the invention will be described below with reference to the accompanying drawings, in which:  
         [0014]      FIG. 1  is a vertical sectional view through a swivel furniture glide having an elastomeric base according to a first embodiment of the present invention;  
         [0015]      FIG. 2  is a perspective view of the elastomeric base of the embodiment of  FIG. 1 ;  
         [0016]      FIG. 3  is a vertical section view through a furniture glide having an elastomeric sliding surface according to a second embodiment of the present invention; and  
         [0017]      FIG. 4  is a perspective view of the furniture glide of the embodiment of  FIG. 3 .  
         [0018]      FIGS. 5 and 6  are plan and sectional elevational views, respectively, alternative to the embodiment shown in  FIGS. 1 and 2 . 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0019]      FIGS. 1 and 2  illustrate a first embodiment of a glide base according to the invention, in the context of swivel furniture glides such as described in U.S. Pat. No. 5,991,974, “Swivelling Furniture Glide” and U.S. Pat. No. 6,154,923, “High Hold Furniture Glide”, and U.S. Publication US2002/0088082A1, the disclosures of which are hereby incorporated by reference.  
         [0020]     A clip and ferrule for receiving a furniture leg, are generally designated by the numerals  10  and  12 , respectively. The ferrule  12  has a circular bottom wall  14  and an upstanding cylindrical side wall  16 . The upper portion of the side wall preferably angles radially inward to define a circular ferrule opening  18 . The ferrule opening  18  is preferably chosen to closely match the outer diameter of the furniture leg (not shown). The bottom wall  14  defines a circular rivet opening  20  coaxial with the ferrule opening  18 . The bottom wall  14  of the ferrule  12  is further preferably contoured having a dropped portion adjacent the rivet opening  20 .  
         [0021]     Clip  10  within the ferrule  12  may take a variety of forms; that depicted in  FIG. 1  is formed from a longitudinal resilient metal strip. The clip  10  has a clip base  22  which has a footprint smaller than the ferrule opening  18 , and a single pair of oppositely positioned clip arms  24 ,  26 . The clip arms  24 ,  26  extend generally perpendicularly upward from the clip base  22 . The unstressed clip arms  24 ,  26  define a neutral diameter greater than the diameter  28  of the ferrule opening  18 . The arms  24 ,  26  and base  22  of the clip  10  are resiliently deformable whereby as the clip  10  is inserted base first into the ferrule opening  18 , the clip arms  24 ,  26  deform inwardly to the smaller diameter  28  of the ferrule opening  18 . The clip arms  24 ,  26  return to generally the neutral shape after passage through the ferrule opening  18 .  
         [0022]     The clip base  22  defines a central clip rivet opening  30 . The clip rivet opening  30  is aligned with the ferrule rivet opening  20  when the clip  10  is mounted in the ferrule  12 . The clip base  22  further projects downward to form a cylindrical portion having a length equivalent to the depth of the contour of the drop portion of the ferrule  12 . The rivet openings  20 ,  30  are of the same diameter.  
         [0023]     A rivet  32  is secured through the clip and ferrule rivet openings  30 ,  20 . The rivet  32  has an expandable head portion  34  and an opposite swivel portion  36 . The head portion  34  of the rivet  32  is inserted through the aligned rivet openings  20 ,  30  and rounded or peened over to pull the swivel portion  36  against the bottom wall  14  of the ferrule  12 . The rivet  32  securely fastens the ferrule  12  and clip  10  together. The clip  10  and ferrule  12 , when riveted together, are capable of fully supporting a furniture leg, and therefore preferably do not require any additional structural elements. The swivel portion  36  of the rivet  32  extends downward from the bottom wall  14  and radially outward to define a convex spherical outer swivel surface and a concentric inner spherical swivel surface.  
         [0024]     A shell assembly  38 , having an inner shell  40  and an outer shell  42 , slidably engages the outer swivel surface of the rivet  32 . The inner shell  40  is generally spherical and defines a circular inner shell opening  44  having a diameter less than the swivel portion  36  of the rivet  32 . The inner shell  40  is nested within the outer shell  42 . The outer shell  42  has a generally frustoconical shape forming an expanded portion  46  defining an outer edge and a reduced portion  48 . The outer shell  42  defines a circular outer shell opening  50  at the reduced portion  48  having a diameter less than the outer diameter of the inner shell  40 . The spherical shape of the inner shell  40  allows for improved swiveling sliding engagement of the inner shell  40  with the outer shell  42 .  
         [0025]     A glide base  52  is mounted to the expanded portion  46  of the outer shell  42 . The glide base  52  is preferably molded as a unitary or singular component of elastomeric material that is softer than material conventionally used for this purpose. The base  52  is circular, having an annular rim portion  54  for engagement to the outer shell  42  and an axial elevated central post portion  56 . The glide base  52  is mounted in position by the crimped outer edge of the outer shell  42 . The post portion  56  of the glide base  52  defines a generally convex base swivel surface in congruent surface-to-surface contact with the inner swivel surface of the rivet  32 . The post portion  56  is dimensioned of a sufficient height to maintain the shell assembly  38  in tight engagement with the swivel portion  36  of the rivet  32 . The swivel portion  36 , inner shell  40 , outer shell  42  and glide base  52  are preferably dimensioned to allow swiveling motion of the ferrule  12  relative to the base  52  of up to 32 degrees from the vertical. Only the outer shell  42  would be required for furniture glides  58  that require a smaller degree of swiveling. The glide base  52  is preferably constructed of thermoplastic polyurethane elastomer. The glide base  52  acts a cushion and has a smooth, circular sliding surface  60  for contacting a floor surface.  
         [0026]      FIGS. 3 and 4  illustrate a second embodiment according to the invention, in the context of a glide such as described in U.S. Pat. No. 6,405,982, “Self-Attaching Sliding Support for Articles of Furniture”, the disclosure of which is hereby incorporated by reference.  
         [0027]     A self-attaching slidable support  110  for an article of furniture includes a first resilient, especially elastomeric, support element  112  and a second, sliding element  114 . Support element  112  includes a relatively thick base portion  116 , which serves to cushion the weight of the article to be supported. Molded integrally with base portion  116  of support element  112  is an upstanding concave inwardly extending circumferential rim  118 . Rim  118  is generally “C” shaped and serves to engage a leg  120  of the article of furniture to be supported. As rim  118  is also preferably formed from elastomeric material, it is free to elastically engage the perimeter of leg  120 . Furthermore, rim  118  is also capable of accommodating legs of a range of sizes and shapes.  
         [0028]     The edge  122  of rim  118  extends inwardly and overhangs the interior space  124  of support element  112 . The diameter of the circular opening  126  of rim  118  is shown as dimension A. However, the diameter of interior space  124  of element  112  is shown as dimension B which is larger than that of dimension A. As rim  118  will elastically deform when leg  120  is inserted therein, support  110  can thus accommodate furniture legs in the diameter range of A to B. Furthermore, rim  118  will also accommodate square or rectangular legs whose diagonal is within the range A to B. This reduces the number of sizes of supports  110  that needs to be carries in stock. In addition, the generally circular support  110  shown herein could also be oval or rectangular in plan view.  
         [0029]     Sliding portion  114  is generally cup shaped and is joined to the underside of support element  112  so that it will rest on the surface on which the article of furniture is to be supported. Sliding portion  114  is preferably fabricated from a thermoplastic polyurethane elastomer  
         [0030]     It should be appreciated that the slidable support  110  according to the second embodiment could alternatively be made of a homogeneous elastomeric material, rather than diverse materials. In either variation, the lower portion  114  defining the sliding surface consists of an elastomeric material, including blends of elastomers, whereas the upper support element or portion  112  is not required to be elastomeric. Similarly, the glide base of the first embodiment could be a composite, so long as the sliding surface is elastomeric.  
         [0031]      FIGS. 5 and 6  show an alternative embodiment to that described above with respect to  FIGS. 1 and 2 . The overall glide  210  of this embodiment has a clip structure including a ferrule  212  within which is supported a generally circular clip member  214  formed with a plurality of recesses or cut-outs, thereby defining individual, downwardly projecting clip arms  216  for firmly securing the substantially tubular lower end of a furniture leg (not shown). A steel rivet  218  passes centrally through the ferrule  212  and has an upper end that is expanded during assembly to trap the clip  214  against the top of the dome  220  formed in the bottom of the ferrule. The ferrule itself rests on a support platform  222  that is in turn supported at the lower end of the rivet, where the rivet has a concave seat  224 . This provides a swivel engagement with the post portion  226  of base  228 . As with the previously described embodiment, preferably, polyurethane base  228  is mounted in position by the crimped outer edges of the cover shell  230 , which in turn is mounted over the inner shell  232 .  
         [0032]     The elastomeric material defining the sliding surface of any embodiment of the invention, is preferably a urethane, especially thermoplastic and particularly a polyester polycaprolactone resin. In general, the elastomer should have hardness in the range of 50-60, preferably about 55, on the Shore D scale. The preferred polyurethane material is available as Dow Series 2102 Pellethane TPE.  
         [0033]     It should also be appreciated that the exclusive rights in the invention are defined by the claims, and are not limited to the preferred embodiments. The elastomeric base or sliding surface according to the invention can be incorporated into other types of swivel glides e.g., such as various combinations of the ferrules, clips, and support shells described in the patents incorporated herein by reference; glides that do not swivel; temporary glides for moving furniture or the like; and glides that are adapted to fit over original equipment glides, such as described in U.S. Pat. No. 6,324,725, “Furniture Glide”.