Captured control knob

Abstract

Apparatus for preventing the removal of control knobs from the control section of a machine. Each knob includes a body section and a radially expanded flange at the lower end of the body section. The knob engages a control shaft of a controllable machine component that passes upwardly through a first panel so that the flange is positioned adjacent to the panel. A second panel having an opening for rotatably containing the body section of the knob is passed over the knob and, when secured in place over the first panel, captures the flange between the panels.

We claim:  
     
         1 . Apparatus for preventing the loss of easily accessed control knobs of a machine that includes: 
 a lower panel having the distal end of a control shaft of a controllable machine component that passes through said lower panel;    a control knob mounted upon the distal end of said control shaft for facilitating rotation of said shaft;    said control knob having a body section and a radially disposed flange mounted upon said body section at the bottom of said body section, said flange being located adjacent to and in parallel alignment with the lower panel; and    a raised upper panel mounted over the cover panel having an opening for rotatably containing the body section of said knob therein, said opening being insufficient to permit the flange from passing therethrough wherein said flange is captured between said upper and lower panels.    
     
     
         2 . The apparatus of  claim 1  that further includes means for supporting the upper panel in spaced apart relationship with said lower panel.  
     
     
         3 . The apparatus of  claim 1  wherein said body section of said knob is cylindrical in form.  
     
     
         4 . The apparatus of  claim 1  that further includes a stop means for limiting the range of rotation of said knob.  
     
     
         5 . The apparatus of  claim 1  wherein said body section and said flange are integrally molded of plastic.  
     
     
         6 . Apparatus for preventing the loss of easily accessible control knobs from the control section of an air conditioning unit that includes 
 a machine support frame containing a first panel;    at least one control shaft associated with a controllable component of the air conditioning unit, the distal end of said shaft passing upwardly through the first panel;    a control knob mounted upon the distal end of said at least one control shaft for rotation therewith, said control knob having a cylindrical body section and a radially expanded flange mounted upon the body section that is adjacent to and parallel with the first panel;    a front cover mounted over the front of the unit containing a second panel that is located in parallel spaced apart relation with said first panel and having an opening therein for rotatably containing the body section of the knob and being of a size insufficient to permit said flange to pass therethrough such that the flange is captured between the first and second panels.    
     
     
         7 . The apparatus of  claim 6  wherein said second panel is located within a well in said front cover, and further includes a hinged door for closing said well.  
     
     
         8 . The apparatus of  claim 6  containing a first control knob for controlling the output temperature of the unit and a second control knob for controlling the mode of operation of the unit.  
     
     
         9 . The apparatus of  claim 6  wherein the control knob and the expanded flange are integrally molded of plastic.  
     
     
         10 . A method of mounting a control knob upon the shaft of a controllable component to prevent removal of the knob that includes the steps of 
 passing the distal end of the shaft of the component through an opening in a first panel,    providing a control knob having a cylindrical body section and a radially disposed flange section which is located at the bottom of said body section,    mounting the knob upon the distal end of said shaft so that said flange is adjacent to said first panel,    mounting a second cover panel over said control panel that has an opening for rotatably containing the body section of said control knob, and which prevents the flange section of the knob from passing through said opening whereby the knob is captured between said panels.    
     
     
         11 . The method of  claim 10  that includes the further step of integrally molding the body section and the flange from plastic.  
     
     
         12 . The method of  claim 10  that includes the further step of limiting the range of movement of said control knob.