Abstract:
A knob for installation on circular and non-circular shafts. The knob includes a hub molded of a thermoplastic material. An elongated socket is formed in the hub and has a transverse cross-section which is complimentary to that of the shaft. Flexible fingers of Y-shaped cross-section are formed in the socket integral with the walls of the socket and spaced from one another around the socket. The flexible fingers extend the length of the socket and are relieved adjacent the shaft receiving entrance to the socket. In a modification, a skirt surrounds the hub and extends outwardly of the socket and the flexible fingers extend outwardly beyond the socket. In another modification, ribs are formed between the fingers.

Description:
BACKGROUND AND SUMMARY OF THE INVENTION 
   The molded knobs of this invention are of the type intended to be installed on shafts of both circular and non-circular transverse cross-sections. 
   One embodiment of this invention is directed to a friction fit knob having resilient, flexible gripping fingers which can securely grip a shaft of circular transverse cross-section to permit turning of the knob to rotate the shaft without slippage of the knob on the shaft and without the necessity of providing a flat section on the shaft. 
   Another embodiment of this invention is directed to a friction fit knob for a shaft having an arcuate surface and a flat surface. 
   An object of this invention is a friction fit knob having resilient, flexible gripping fingers spaced around the inner wall of the knob socket and positioned to engage an outer surface of the shaft which improves the anti-slip engagement of the knob with the shaft. 
   Another object of this invention is a friction fit knob having resilient, flexible gripping fingers which can grip a shaft of fully circular transverse cross-section thereby avoiding the orientation problems inherent with the installation of knobs on shafts which are non-circular in transverse cross-section or have a flattened section. 
   Yet another object of this invention are resilient, flexible shaft gripping fingers which allow a knob to pilot on the shaft to which it is being applied before the gripping fingers are engaged by the shaft to avoid damaging the gripping fingers during installation. 
   Still another object of this invention is a friction fit knob having resilient, flexible shaft gripping fingers which apply gripping pressure around the entire periphery of the shaft. 
   Other objects of the invention will be found in the following specification, claims and drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is illustrated more or less diagrammatically in the following drawings wherein: 
       FIG. 1  is a longitudinal cross-sectional view of a first embodiment of a knob of this invention; 
       FIG. 2  is an enlarged bottom plan view of the knob of  FIG. 1  with parts other than the core omitted or shown in phantom lines; 
       FIG. 3  is a view similar to  FIG. 2  but showing a shaft of circular transverse cross-section seated in the socket of the knob; 
       FIG. 4  is a longitudinal cross-sectional view of a second embodiment of a knob of this invention; 
       FIG. 5  is an enlarged bottom plan view the knob of  FIG. 4  with parts other than the core omitted or shown in phantom lines; 
       FIG. 6  is an isometric view of a longitudinally extending cross-section of the knob of  FIG. 4 ; 
       FIG. 7  is an enlarged bottom plan view of a third embodiment of a knob of this invention; 
       FIG. 8  is a cross-sectional view on a reduced scale taken along line  8 — 8  of  FIG. 7 ; 
       FIG. 9  is a cross-sectional view on a reduced scale taken along line  9 — 9  of  FIG. 7 ; and 
       FIG. 10  is an enlarged bottom plan view of the knob of  FIG. 7  with parts other than the core and portions of the ribs omitted for clarity of illustration. 
       FIG. 11  is an enlarged bottom view of a fourth embodiment of a knob of this invention; 
       FIG. 12  is a cross-sectional view taken along line  12 — 12  of  FIG. 11 ; 
       FIG. 13  is a cross-sectional view taken along line  13 — 13  of  FIG. 11 ; and 
       FIG. 14  is an enlarged bottom plan view of the knob of  FIG. 11  with portions omitted. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIGS. 1-3  of the drawings show a first embodiment of a molded knob  11  of this invention which is adapted to fit over a circular shaft  13  which has a circular outer surface  15 , which shaft is often formed of metal. The invention is adaptable to many types of knobs and while a few will be shown and described in this specification, it should be understood and appreciated that the invention is usable with many other types of knobs in addition to those specifically described herein. The knob  11  includes a hub  21 , a front enclosing wall  23  and a tubular outer wall  25 . The tubular outer wall  25  ends in a distal end edge  27  which surrounds an open end  29  leading into a chamber  31 . An annular flange  33  is formed on the end edge  27 . 
   A shaft receiving socket  35  is formed in the hub  21  with the socket having a bottom or end surface  37  at the front end closing wall  23  of the knob. A circular shaft stop  39  extends from the bottom or end surface  37  of the knob closing wall  23 . The shaft receiving socket includes a cylindrical interior wall  41  with a shaft receiving entrance  43  to the socket  35 . 
   Fingers  51  are formed inside the socket  35  and extend the length of the cylindrical interior wall  41  of the socket. As can best be seen in  FIGS. 2 and 3  of the drawings, the fingers  51  connect to the wall  41  by webs  53  with ribs  55  extending outwardly on opposite sides of the webs to form the fingers  51  that are generally Y-shaped in transverse cross-section. The distal ends of the fingers near the shaft receiving entrance  43  to the socket are relieved at  57  to provide leads which allow the knob to pilot on the circular shaft  13  before the shaft engages and is held by the ribs  55  of the fingers  51 . 
   An enlarged bore  61  is formed outwardly of the shaft receiving entrance  43  to the socket  35 . The enlarged bore has a tapered circumferential wall  63  with the enlarged bore minimizing rocking of the knob on the shaft  13  when the shaft enters the enlarged bore and before engaging the fingers  51  inside the shaft receiving socket  35 . 
   A second embodiment of the invention and a variation thereof are shown in  FIGS. 4 ,  5  and  6  of the drawings. Molded knob  71  includes a front end or closing wall  73  and a tubular outer wall  75  which terminates in an end edge  77  surrounding an open end  79  which leads into an enlarged bore  81  extending from the open end  79  of the knob. Located inwardly of the enlarged bore  81  is a shaft receiving socket  85  having a bottom surface  87  at the front closing wall  73 . A circular shaft stop  89  extends longitudinally from said bottom wall  87 . The shaft receiving socket has a cylindrically-shaped interior wall  91  which extends to a shaft receiving entrance  93  to the socket. 
   Shaft engaging fingers  95  are formed on the cylindrical interior wall  91  of the socket and each includes a web  97  formed integrally with the tubular outer wall  75  of the knob with ribs  99  extending generally outwardly of the web to form the fingers  95  of generally Y-shaped transverse cross-section as can best be seen in FIG.  5 . The fingers  95  have columnar extensions  101  which extend beyond the socket  85  and into the enlarged bore  81  with the extensions having the same Y-shaped cross-sections as previously described. In  FIG. 6  of the drawings, the tips  103  of the columnar extensions  101  of the fingers are flat, but in the variation of  FIG. 5 , the fingers are beveled at  105  to form a lead for insertion of the shaft into the socket  85 . The columnar extensions  101  of the fingers  95  that extend beyond the socket  85  act as a piloting feature to assist the insertion of the circular shaft into the socket  85 . 
   A third embodiment of the invention is shown in  FIGS. 7 ,  8 ,  9  and  10  of the drawings. In the third embodiment of the invention, a molded knob  111  is formed with a hub  113 , a front end enclosing wall  115 , a tubular outer wall  117  and a distal skirt portion  119  of reduced thickness beginning at a shoulder  121  of the tubular outer wall. The skirt portion  119  has an end edge  123  defining an open end  125  leading into a knob chamber  127 . A shaft receiving socket  131  is formed in the hub  113  and has a bottom or end surface  133  at the front end enclosing wall  115  of the knob. An annular shaft stop  135  extends from the bottom surface  133 . The shaft receiving socket has a cylindrical interior wall  137  which extends to a shaft receiving entrance  139  to the socket. An enlarged bore  141  is formed in the hub outwardly of the shaft receiving entrance  139 . Webs  143  extend between hub  113  and the generally tubular outer wall  117  of the knob. 
   Fingers  151  are formed integrally with the cylindrical interior wall  137  of the socket and project diametrically inwardly of the socket while extending the length of the cylindrical interior wall  137  of the socket from the bottom surface  133  to the shaft receiving entrance  139 . As can be seen more clearly in the enlarged partial view of  FIG. 10 , each finger is Y-shaped in transverse cross-section and includes a web  153  formed integrally with the hub  113  and have ribs  155  extending generally outwardly on opposite sides of the web to form the Y-shaped fingers. 
   The distal ends of the fingers  151  near the shaft receiving entrance  139  to the socket  131  are relieved at  157  to allow the knob to pilot on the circular shaft before the shaft engages the fingers. The enlarged bore  141  engages the circular shaft before it contacts the fingers  151  to minimize rocking of the knob on the shaft during installation. Ribs  159  are formed on the cylindrical inner wall  137  of the shaft receiving socket  131  and are located between the fingers  151 . The ribs project radially inwardly to assist the fingers  151  in centering the shaft. The ribs  159  are not relieved near the shaft receiving entrance  139  to the socket  131 . 
   A fourth embodiment of the invention is shown in  11 ,  12 ,  13 , and  14  of the drawings. In this embodiment, a molded knob  171  is formed with a hub  173 , a front end enclosing wall  175 , a tubular outer wall  177 , and a distal skirt portion  179  of increased thickness. The skirt portion  179  has an end edge  181  defining an open end  183  leading into a knob chamber  185 . A shaft receiving socket  187  of substantially D-shaped transverse cross-section is formed in the hub  173  and has a bottom or end surface  189  at the front end enclosing wall  175  of the knob. A cylindrical shaft stop  191  extends from the bottom surface or end surface  189  of the socket. As shown most clearly in  FIG. 14 , the socket includes an arcuate interior wall portion  193  and a flat wall portion  195  which is recessed from the arcuate portion, both of which extend to a shaft receiving entrance  197  to the socket. 
   Fingers  201  are formed integrally with the interior wall portions  193  and  195  of the socket and project diametrically inwardly of the socket while extending the lengths of the interior wall portions  193  and  195  to the shaft receiving entrance  197 . 
   As can be seen most clearly in FIG.  11  and in the enlarged partial view of  FIG. 14 , each finger is Y-shaped in transverse cross-section and includes a web  203  formed integrally with the hub  173 . Each finger has ribs  205  extending generally laterally on opposite sides of the web to form the fingers  201  that are generally Y-shaped in transverse cross-section. 
   The distal ends of the fingers  201  near the shaft receiving entrance  197  are relieved at  207  to allow the knob to pilot on the shaft before the shaft engages the fingers. Ribs  209  are formed on the arcuate interior wall portion  193  and on the flat wall portion  195  of the shaft receiving socket  187  and are located between the fingers  201 . The ribs  209  project inwardly to assist the fingers  201  in centering the shaft. The ribs  209  are not relieved near the shaft receiving entrance  197  to the socket  187 . Notched corners  211  are provided between the arcuate interior wall  193  and the recessed flat wall portion  195 . The notched corners  211  in conjunction with the ribs  205  and the ribs  209  take up torque from the shaft.