Abstract:
An adjustable engagement glide is quickly and removably engaged with tubular products to finish the product end and function as a cap, foot, bumper, or scratch protector on products such as furniture, shop and transportation products, and racks and displays. Engagement is by deformation of a resilient bushing frictionally engaging the tubular product inserted in the glide. The glide is configured for severe service without breakage, has provision to protect surfaces upon which it is supported, but may also be easily disengaged from the product for replacement.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   Not Applicable. 
   STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT 
   Not Applicable. 
   REFERENCE TO A MICROFICHE APPENDIX 
   Not Applicable. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This application relates to a glide and the method of installing the glide on tubular products to provide adjustable engagement that is releasable. A glide is an apparatus used in many industries to perform a variety of functions. Most commonly glides are used to finish the end of a tubular product, and function as caps, feet, bumpers, or scratch protectors on products such as furniture, shop and transportation products, and racks and displays. In this patent application tubular products are construed to include hollow materials with circular, elliptical, rectangular, or other conic or polygon cross-section. 
   2. Description of Related Art 
   Glides are well known in the art as devices for providing a finishing device on a tubular product to prevent injury due to sharp surfaces, to prevent scratching of surfaces in contact with the tubular product, to reduce noise caused by contact with the end of a tubular product, and to provide a finished look to a tubular product. 
   The prior art glides use a frictional attachment to the tubular product that is intended to provide a semi-permanent attachment. These are prone to wear when in severe services that are prone to impact and vibration, and thus may become loose or missing in such service. Alternately, if the glide is complicated in design, such as those that swivel, the glide may become broken and the broken glide may be difficult to remove from the tubular product. Glides that use this type of attachment in furniture service are taught in U.S. Pat. Nos. 5,991,974 (Carpinella), 6,154,923 (Carpinella), 6,219,882 (Olson), 6,324,725 (Green), 6,719,256 (Rydell et al.), 6,910,246 (Desmarais). 
   The present invention overcomes these disadvantages of the prior art by providing a glide that is sturdy, is installed with adjustable engagement with the tubular product, and may be disengaged from the tubular product when desirable. 
   SUMMARY OF THE INVENTION 
   This invention is an adjustable engagement glide for installation on a tubular product. The glide has a main body, a bolt with a head portion and a threaded portion, a bushing, and a bushing deformation nut. 
   The main body is a single piece with an outer surface, an inner surface, an attachment extension also with an inner surface and an outer surface, and also with a first end engaged with the body inner surface, and a second end. A countersink opening is arranged between the outer surface and the inner surface of the main body such that the opening is centrally arranged with the attachment extension first end. 
   The bushing has a first end and a second end, an outside surface, and a through-hole arranged between the first and second ends, the through-hole arranged so the bolt threaded portion fits within the hole. The bushing deformation nut is arranged with a threaded portion to threadedly engage the bolt threaded portion and the bolt is arranged with the bolt head in the main body countersink opening. This allows the bolt threaded portion to extend centrally into the attachment extension and through the bushing through-hole, thus forming an installation annulus between the attachment extension inner surface and the bushing outside surface. 
   The bushing deformation nut is in frictional engagement with the bushing by placing a slight pretension with the bolt. Turning the bolt head in the tightening direction causes the nut to compressively engage the bushing, and turning the bolt head in the opposite direction releases the compressive engagement of the bushing. When the tubular product is inserted in the installation annulus and the bolt head turned to compressively engage the bushing, deformation of the bushing causes adjustable engagement with the tubular product. 
   The body inner surface forms a concavity around the attachment extension with a concavity end arranged such that the attachment extension is located within the main body concavity. This concavity allows impact forces to the glide to be absorbed by elastic deformation of the glide rather than damaging the glide. 
   An upper body is arranged to engage the main body at the concavity end and further arranged to engage the attachment extension at the extension second end. It thus encloses the main body from the concavity end to the attachment extension second end. This provides an attractive, finished appearance to the glide and reduces the exposed crevices prone to the collection of dirt. 
   The glide bolt and nut is pretensioned prior to installation so that the friction of the bushing on the nut assures tightening the bolt turns it within the nut threads and deforms the bushing, rather than spinning the nut without engagement with the bushing. The glide is installed by inserting the tubular product end into the installation annulus such that the tubular product end contacts the installation annulus bottom end, and then tightening the bolt such that the tubular product is forced into adjustable engagement between the bushing and attachment extension inner surface. Alternately the pretension may be adjusted to give a press-on fit to the tubular product. In this alternative sufficient force is applied to insert the tubular product end between the attachment extension inner surface and the bushing. 
   OBJECTS AND ADVANTAGES 
   One object of the present invention is to provide a guide that is easily and adjustably engaged with tubular products. 
   A second object of the present invention is to provide a guide that resists breakage in severe service, but is easily removed for replacement. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     A more complete understanding of the present invention can be obtained by considering the detailed description in conjunction with the accompanying drawings, in which: 
       FIG. 1  is a side view of an angled glide with a first embodiment of the attachment means. 
       FIG. 2  is a side view of a straight glide with a first embodiment of the attachment means. 
       FIG. 3  is a side view of an angled glide with a second embodiment of the attachment means. 
       FIG. 4  is a side view of a straight glide with a second embodiment of the attachment means. 
       FIG. 5  is a top view of a straight glide with a first embodiment of the attachment means. 
       FIG. 6  is a top view of a straight glide with a second embodiment of the attachment means. 
       FIG. 7  is a bottom view of an angled glide with a first embodiment of the attachment means. 
       FIG. 8  is a bottom view of a straight glide with a second embodiment of the attachment means. 
       FIG. 9  is a cut-away view of a straight glide with a second embodiment of the attachment means. The tubular product is shown in dashed lines as inserted in the glide. 
       FIG. 10  is a cut-away view of a straight glide with a second embodiment of the attachment means showing the glide engaged with a tubular product. The tubular product is shown in dashed lines as inserted in the glide. 
       FIG. 11  cut-away view of a straight glide with a first embodiment of the attachment means showing the glide engaged with a tubular product. The tubular product is shown in dashed lines as inserted in the glide. 
       FIG. 12  is an exploded view of an angled glide showing both a first and second embodiment of the attachment means. 
   

   REFERENCE NUMERALS IN DRAWINGS 
   These reference numbers are used in the drawings to refer to areas or features of the invention.
           30  Main Body     32  Main Body Outer Surface     33  Main Body Surface Contact Area     34  Main Body Inner Surface     40  Main Body Concavity     42  Main Body Concavity End     44  Main Body Attachment Extension     45  Main Body Attachment Extension Inner Surface     45   b  Main Body Attachment Extension Outer Surface     46  Main Body Attachment Extension First End     48  Main Body Attachment Extension Second End     50  Main Body Countersink Opening     60  Bolt     62  Bolt Head Portion     64  Bolt Threaded Portion     70  Bushing     70   a  Molded Bushing     70   b  Sleeve Bushing     72  Bushing Through Hole     74  Bushing First End     76  Bushing Second End     78  Bushing Outside Surface     80  Bushing Deformation Nut     80   a  Molded Bushing Nut     80   b  Sleeve Bushing Wedge Nut     81   b  Sleeve bushing Wedge Nut Holder     82  Bushing Deformation Nut Threaded Portion     90  Installation Annulus     92  Installation Annulus Bottom End     94  Installation Annulus Entry End     100  Upper Body     102  Upper Body First End     104  Upper Body Second End     110  Surface Protection Attachment     120  Tubular Product       

   DETAILED DESCRIPTION OF THE INVENTION 
   The assembled adjustable engagement glide is shown in side views of two models in  FIGS. 1 ,  2 ,  3 , and  4 ,  FIGS. 1 and 3  show the model for engagement with an angled tubular product, such as might be used on a chair leg that meets the supporting surface at an angle, and  FIGS. 2 and 4  the second model for engagement with a straight tubular product, such as might be used for a table or chair leg that is vertical with the supporting surface on which it rests.  FIGS. 5 and 6  show a top view of the glide for a straight tubular product. There is shown in  FIGS. 1 through 6  a first and a second embodiment of attachment means to the tubular product. The first embodiment is shown in  FIGS. 1 ,  2 , and  5 , the second embodiment in  FIGS. 3 ,  4 , and  6 . Bottom views of the two models, straight and angled, are shown in  FIGS. 7 and 8  respectively. 
   In either model, straight or angled, the glide has a main body ( 30 ) and an upper body ( 100 ) joined to form a unitary structure. The main body contains the adjustable engagement means that consists of the items shown in cut-away views in  FIGS. 9 ,  10  and  11 , and in exploded view in  FIG. 12 . The upper body encloses the main body structure and is joined by welding or glue to form the unitary structure. The main body is molded with an attachment extension portion and a concavity portion. The concavity portion has an outer surface ( 32 ), and an inner surface ( 34 ). The inner surface contains a concavity ( 40 ) with a concavity end ( 42 ) that is also one attachment point for the upper body ( 100 ). The concavity may contain structural ribs to enhance the geometric stability of the glide, and the concavity also functions to allow elastic deformation of the glide due to impact forces, providing impact absorption in severe service. This provides means for absorbing impact forces normal to the tubular product axis on a surface offset from and surrounding the tubular product as shown in  FIGS. 9 ,  10  and  11 . The concavity inner surface is also integral with the attachment extension portion that has an attachment extension ( 44 ) with a first end ( 46 ) where it is molded with the concavity portion inner surface to form the main body, and a second end ( 48 ) that is the second attachment point for the upper body ( 100 ). Between the main body outer and inner surface there is a countersink opening ( 50 ) located centrally in the attachment extension first end ( 44 ). The countersink opening is sized to allow through passage of the bolt threaded portion ( 64 ) while keeping the bolt head portion ( 62 ) within the countersink. The opening may not include a countersink in which case the bolt head portion ( 62 ) may protrude from the main body outer surface. 
   The engagement means is shown in cross-sectional view of a first embodiment in  FIG. 9  and the same embodiment engaged with a tubular product in  FIG. 10 . A second embodiment of the engagement means is shown in cross-sectional view in  FIG. 11 . The engagement means is located within the main body attachment extension ( 44 ) and consists of the bolt ( 60 ) with a head portion ( 62 ), which is the means for adjusting the engagement means, located within the countersink opening ( 50 ) and the threaded portion ( 64 ) extending centrally into the attachment extension. A bushing ( 70 ) with a through hole ( 72 ) located between the first end ( 74 ) and the second end ( 76 ) is installed around the bolt threaded portion ( 64 ), and a bushing deformation nut ( 80 ) with a threaded portion ( 82 ), which mates with the threads of the bolt threaded portion ( 64 ), is installed at the bushing second end ( 76 ). In the embodiment shown in  FIGS. 9 and 10  the molded bushing nut ( 80   a ) acts on the molded bushing second end ( 76 ) to deform the bushing. In the embodiment shown in  FIG. 11  the sleeve bushing wedge nut ( 80   b ) acts on the bushing through hole ( 72 ) to deform the bushing. The space between the attachment extension ( 44 ) and the bushing ( 70 ) forms an installation annulus ( 90 ) into which the tubular product onto which the glide is to be engaged may be inserted. This annulus has a bottom end ( 92 ) formed by the main body inner surface ( 34 ) and an entry end ( 94 ) that provides opening means for inserting the tubular product into the glide. The annulus may be shaped generally like the tubular product to which the glide is to be installed or any shape that fosters frictional engagement of the tubular product between the attachment extension inner surface and the bushing. The bushing is made of a resilient deformable material (example soft plastic, rubber). The bolt ( 60 ) and bushing deformation nut ( 80 ) are pretensioned to provide a deformation of the bushing ( 70 ) so that the nut&#39;s frictional engagement with the bushing allows turning the bolt without turning the nut, thus moving the nut axially along the bolt threads and allowing the bushing to be further compressively deformed, or the deformation relaxed. The bolt head, that is the means for adjusting the engagement means, is turned from the exterior surface of the main body using well known tools. Alternately the pretension may be adjusted to provide an installation annulus ( 90 ) that is a desired dimension smaller than the wall thickness of the tubular product ( 120 ). This arrangement provides a press-on fit for installing the guide on the tubular product. 
   Two embodiments of the engagement means are shown in  FIG. 12 . One using a molded bushing ( 70   a ) and the second using a sleeve bushing ( 70   b ). Each embodiment uses a different arrangement of the bushing deformation nut ( 80 ), the first embodiment has a molded bushing nut ( 80   a ) with means for engaging the molded bushing second end ( 76 ), the second embodiment has a sleeve bushing wedge nut ( 80   b ) with means for engaging the hole in the sleeve bushing at the bushing second end ( 76 ). 
   Operation 
   The adjustable engagement glide is installed on a tubular product by inserting the glide installation annulus on the tubular product so the product end is on the bottom end of the installation annulus ( 92 ). The bolt ( 60 ) is then turned in the tightening direction in the bushing deformation nut ( 80 ) so the bushing ( 70 ) is deformed between the bolt and nut. The tightening is continued until the bushing deforms sufficiently to press against the tubular product forming a frictional bond with the product. The glide is then adjustably frictionally engaged with the product in that the frictional engagement with the tubular product may be adjusted by the bolt. 
   Alternately the pretension may be adjusted to provide an installation annulus ( 90 ) that is a desired dimension smaller than the wall thickness of the tubular product ( 120 ). This provides a press-on fit that requires application of sufficient force to the glide to overcome the frictional resistance of the bushing and press the glide on the tubular product. The glide is then adjustably frictionally engaged with the product in that the frictional engagement with the tubular product may be adjusted by the bolt. 
   A surface protection attachment ( 110 ) may be installed by adhesive or other common attachment method on the main body surface contact area ( 33 ) for service where scratch-resistance is desired. This means for surface protection may be a non-scratching soft material (example felt) or a low friction material (examples polyethelene or Teflon) that provides an interface that will not damage the surface with which the glide is in contact. 
   A means for adjustment after installation or removal of the adjustable engagement glide may be done by removing any surface protection attachment installed on the glide and turning the bolt head. Removal requires turning in the loosening direction until the deformation of the bushing is released sufficiently to disengage the bushing from the tubular product, at which point the glide may be slid off the tubular product. 
   ADDITIONAL EMBODIMENTS 
   Those familiar with the art recognize there are many possible applications and variations for the adjustable engagement glide other than the embodiments recited. The glide may vary in geometric shape to provide other uses from those taught, or may use different contact configurations to achieve deformation of the bushing by tightening the nut on the bolt such as a nut and washer, a spherical contact surface, a bushing wedge located in the main body inner surface to which the bushing is drawn against, etc. The glide may also have the pretension on the bushing adjusted to provide a press-on fit to the tubular product in these alternative arrangements. A press-on fit provides sufficient friction on the tubular product to resist removal of the installed guide. This embodiment is installed with sufficient force to press the tubular product wall into the installation annulus. This recitation of the preferred and other embodiments is not intended to define or constrain the invention; rather the claims define the invention.