Abstract:
A control for a fluid cylinder includes a cylindrical housing made of a polymeric material which pivotally receives a control arm having a cable release receiving member at one end and which can be snap-fitted within an open end of a pneumatic cylinder to lockably engage a valve spacer manufactured as part of the cylinder. With such a system, the control can be installed in the cylinder and rotated to position the cable release in any orientation within a 360° adjustment range to allow proper alignment of the cable release.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     The present invention relates to a control for use in connection with an adjustable pneumatic cylinder.  
         [0002]     Pneumatic adjustment cylinders are frequently employed for adjusting a movable member with respect to a fixed base. Frequently, such cylinders are employed in connection with adjustable height office chairs, tables, and the like. In the past, controls for actuating the valves for such adjustable cylinders have been manufactured such that they position the cable control in a direction for mounting to the chair or table in a particular orientation, such as the left side, right side, center or other location. In such installations, it is necessary to properly align the pneumatic cylinder during assembly in the chair or table such that the cable control is correctly positioned for coupling to an actuator, lever, or button. Slight misalignment can cause excessive wear during use or inoperability of the control. There exists a need, therefore, for a pneumatic cylinder valve control which facilitates installation and which allows adjustability of the exit position of the control cable therefor and one which can be used with existing cylinder designs.  
       SUMMARY OF THE INVENTION  
       [0003]     The control of the present invention satisfies this need by providing a housing made of a polymeric material which pivotally receives a control arm having a cable control receiving member at one end and which can be snap-fitted within an open end of a fluid cylinder after its manufacture. With such a system, the control can be installed in the fluid cylinder, such as a pneumatic cylinder, and rotated to position a cable control in any orientation within a 360° adjustment range to allow proper alignment of the cable control to the desired location. Such a universal snap-in control, therefore, can be used for left, right, middle, or any other location in, for example, a chair, thereby providing the manufacturer the options of locating the actuator, lever, or button at any desired position. The control system components can be molded of a suitable polymeric material and easily assembled, and subsequently snap-fitted within an existing pneumatic cylinder, thereby reducing the cost of a control system as well as providing desired flexibility for installation.  
         [0004]     These and other features, objects and advantages of the present invention will become apparent upon reading the following description thereof together with reference to the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0005]      FIG. 1  is a vertical cross-sectional view, partly broken away, of a pneumatic cylinder installation embodying the control system of the present invention;  
         [0006]      FIG. 2  is a fragmentary exploded view, partly in cross section, of the control system components and pneumatic cylinder;  
         [0007]      FIG. 3  is an enlarged fragmentary cross-sectional view showing the assembly of components of the control of the present invention;  
         [0008]      FIG. 4  is a left side elevational view of the housing and control arm shown in  FIG. 3 ;  
         [0009]      FIG. 5  is a right side view of the assembled structure shown in  FIG. 3 , shown partly in cross section;  
         [0010]      FIG. 6  is a vertical cross-sectional View showing the insertion of the control components of  FIGS. 4 and 5  into a cylinder;  
         [0011]      FIG. 7  is an enlarged fragmentary vertical cross-sectional view of the control elements shown in an assembled position in the valve open actuation position; and  
         [0012]      FIG. 8  is a top plan view of the control and cylinder shown in  FIG. 7 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0013]     Referring initially to  FIG. 1 , there is shown a pneumatic cylinder  10  incorporating the control system of the present invention. Cylinder  10  includes an outer cylindrical housing  12  in which there is positioned a piston  14  coupled to a piston rod  16 , which extends downwardly to a thrust bearing  18  coupled to a base  20 , such as a chair base to allow rotation of the cylinder  10  with respect to the base  20 . A cover sleeve  22  extends over the piston rod  16  and slidably engages the outer cylindrical surface of cylinder  10  to allow, upon actuation of the control valve  24  by the control assembly  30  of the present invention, a support member  60 , such as the chair bottom to be vertically adjustable with respect to base  20 . The upper end of cylinder  10  is tapered at  13  and is received in a tapered socket  15  of bracket  17  coupled to the bottom  62  of the chair or table  60 . Opening  19  in bracket  17  provides access to the upper end of cylinder  10  and allows installation of the cable control  30 , described below, and attachment of a release or control cable  65  thereto, which extends to a push-button (or other type) control  70  which can be positioned at any desired location within a chair or table due to the unique nature of the control  30 .  
         [0014]     As best seen in  FIGS. 1 and 7 , valve  24  has a control element or rod  25  extending upwardly and which is selectively engaged by control  30  of the present invention. The cylinder  10  includes a valve spacer  21  which is crimped to the top opening of housing  12 , as best seen in  FIG. 6 . Valve spacer  21  includes an annular undercut surface  23  ( FIG. 2 ) which secures the snap-fit control  30  therein, as seen in  FIGS. 1 and 7 , once control  30  is inserted into the top opening  26  of spacer  21 , as illustrated in  FIG. 6 .  
         [0015]     Control  30  includes an actuating button  32  which includes a central axially extending blind aperture  34  for receiving control rod  25  of valve  24 . As best seen in  FIG. 3 , button  32  includes a camming upper surface  36  which is elliptically curved from the outer edge  33  to the crown  35  to engage a rounded camming surface  45  on control arm  40  of control  30 . The control arm  40  is pivotally received within housing  50 , as described below.  
         [0016]     Housing  50  is generally cylindrical and includes vertical slots  52  along its lower cylindrical side wall to allow flexibility for the bottom outwardly projecting arcuate flanges  54 , which engage the annular surface  23  of valve spacer  21 , as best seen in  FIGS. 1, 7 , and  8 , when assembled. The four 90° spaced slots  52  thereby define four resilient legs  53  of housing  50  ( FIGS. 4 and 5 ) to allow them to deflect and extend within the cylindrical opening  26  of valve spacer  21  during insertion of the assembly, as illustrated by arrow A in  FIG. 6 . Housing  50  includes an open top  56  through which control arm  40  extends once assembled, as seen in  FIG. 6 . A cylindrical socket  57  ( FIGS. 4 and 5 ) is formed in a mounting boss  58  on the inner cylindrical side  59  of the housing for receiving a pivot axle  47  on control arm  40 . Control arm  40  is inserted upwardly into the lower open end  55  of housing  50 , as illustrated by arrow B in  FIGS. 3 and 4 , until the pivot axle  47 , extending from opposite sides of control arm  40 , engages and snap-fits within socket  57 .  
         [0017]     The control cam  45  of control arm  40  is offset from pivot axle  47  such that pivotal movement of the upper end  44  of arm  40  will provide a mechanical advantage due to the spacing between pivot axle  47  and cam  45  and the greater distance between pivot axle  47  and end  44  to actuate control button  32  against the pneumatic pressure of valve control element or rod  25 . End  44  of control arm  40  includes a radially and axially extending slot  46  for receiving a standard cylindrical end of a cable release  65  which can be extended within the cylindrical opening  48  of slot  46  and rotated until the cable is captively held to end  44  of control arm  40 .  
         [0018]     The actuating button  32 , housing  50 , and control arm  40  can all be individually integrally molded of a suitable polymeric material, such as acetal, which provides the necessary strength and rigidity and yet flexibility for the snap-insertion of housing  50  into valve spacer  21 , as illustrated in  FIG. 6 , to an installed position, as shown in  FIG. 7 , in which the camming surface  45  of control arm  40  is shown in an opening position for valve  24 . Thus, arm  40  is moved to the right, as shown by arrow C ( FIG. 7 ) to depress button  32  actuating valve  22  for lowering the element  60  with respect to base  20 .  
         [0019]     Control  30  can, thus, be assembled to pneumatic cylinder  10  by inserting control button  32  downwardly through open end  26  of the spacer  21 , positioning control arm  40  into housing  50  and subsequently snap-fitting the housing downwardly into opening  26  deflecting legs  53  until flanges  54  engaged the annular surface  23  of valve spacer  21 , which snap-fits control  30  into open end  26  of pneumatic cylinder  10 . The polymeric interface between the typically aluminum valve spacer  21  and the housing  50  allows the housing and control arm pivotally mounted thereto to rotate, as seen by arrow D in  FIG. 8 , through 360°, allowing positioning of release cable  65  at any desired location with respect to the element being controlled by cylinder  10 . Thus, the control  30  will permit left side, right side, front, rear, or any incremental position therebetween for the positioning of push-button or other type of actuating control  70  on, for example, a chair base or arm or to the undersurface of a table at any desired location.  
         [0020]     Typically, during manufacture of a chair, the cable release  65  and control  70  will be prepositioned and the coupling of the end of cable  65  to control  30  can be easily accommodated as the control cylinder  10  is secured to the chair base and undersurface of the chair to accommodate whatever position cable  65  is located. Thus, the system of the present invention provides a great degree of flexibility for the manufacturer and provides an inexpensive, durable, and flexible control for activating an adjustable fluid cylinder.  
         [0021]     It will become apparent to those skilled in the art that various modifications to the preferred embodiment of the invention as described herein can be made without departing from the spirit or scope of the invention as defined by the appended claims.