Abstract:
A two-way actuator device having a lever with a handle portion near a first end and a bearing portion near a second, opposing end for applying force to a responsive device. Two pivots are provided on the lever and located on opposing sides of the bearing portion. The pivots are biased so that the bearing portion moves in a direction opposite to the handle portion when the handle portion is moved in a first direction and the bearing portion moves in the same direction as a handle portion when the handle portion is moved in a second direction, opposite to the first direction.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to chair height adjustment mechanisms and more particularly to a control actuator for a pneumatic or gas spring adjustment mechanism. 
     A fairly wide variety of chair or seating vertical height adjustment mechanisms are currently available. A typical office chair, for example, includes a seat, a back portion and a support pedestal. The support pedestal usually incorporates a chair height adjustment mechanism which raises the seat height with respect to floor level. The pedestal or base may include threadably interconnected and relatively positionable elements. In the alternative, a pneumatic or gas spring is provided for height adjustment. The gas spring includes a piston rod connected to a piston which rides within a cylinder. A release pin extends from an outer end of the cylinder or housing through a seal. The release pin serves as an actuator for releasing or locking the piston in a desired set position and for setting the initial or unloaded chair height. An actuator handle or lever located under the seat cushion of the chair is provided to engage the release pin and selectively release or lock the height adjustment mechanism. The lever or control actuator is typically movable in one of an upward, downward, backward or forward direction. An example of a chair height adjustment mechanism incorporating a gas spring may be found in U.S. Pat. No. 3,711,054 entitled CONTINUOUSLY ADJUSTABLE LIFTING DEVICES and issued on Jan. 16, 1973 to Bauer. 
     Problems have been experienced with user operation of the control actuators. A user unfamiliar with the particular mechanism will not know which direction within which to move the height control lever or control actuator. If the actuator functions to control the release pin when it is pulled in the upward direction, the actuator handle may be broken or bent should the user place their full weight onto the handle and push downwardly. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention, the aforementioned problems are solved. Essentially, a control actuator is provided for engaging a release pin or the like of a chair height adjustment mechanism. The actuator includes an elongated lever having a handle portion and a bearing portion. Pivot means engage the lever when the handle portion is moved in a first direction so that the bearing portion moves in a predetermined direction. The pivot means also engage the lever at another point when the handle is moved in a second direction so that the bearing portion again moves in the predetermined direction The release pin or control button of the height adjustment mechanism is engaged and actuated when the handle portion is moved in either of two directions. 
     In narrower aspects of the invention, the actuator device includes a plate defining an aperture through which the lever extends. The lever includes a pivot which engages the plate at the aperture when the handle is moved in the first direction. The plate and lever define another pivot which is operative when the handle is moved in the second direction. In a preferred form, the second pivot is defined by a generally hook shaped fulcrum extending through another aperture in the plate. 
     By virtue of the dual or two-way operation of the actuator in accordance with the present invention, problems heretofore experienced with bending or damage to the actuator handle are eliminated. A user can actuate the height control mechanism by pulling up or pushing down on the handle portion. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded perspective view of a two-way actuator according to the present invention. 
     FIG. 2 is a partial sectional and partial rear elevational view of the actuator of FIG. 1. 
     FIG. 3 is the view of FIG. 2 with the actuator manipulated in a first direction. 
     FIG. 4 is the view of FIG. 2 with the actuator manipulated in a second direction. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     An actuator device in accordance with the present invention is illustrated in FIG. 1 and generally designated by the numeral 10. Device 10 includes a lever 11 having a grasp 12, an elongated handle portion 14, a fulcrum block or pivot member 16, a bearing bar 18 and another pivot member in the form of a fulcrum hook 20. Handle portion 14 is generally L-shaped including a generally horizontal leg 15 and a generally vertical leg 17. Actuator device 10 may be used with a height adjustable chair base 110, having a conventional height adjustment mechanism which is released for adjustment by depressing a control button or release pin 112. Base 110 includes a plate 114 which defines a pivot seat 22 at an aperture 116. Another pivot seat 24 is defined in chair base plate 110 by a second aperture 118. Aperture 118 receives fulcrum hook 20 at the end of the lever. Lever 11 extends through aperture 116. 
     Fulcrum hook 20 is a generally hook shaped portion formed at one end of bearing bar 18. Fulcrum hook 20 has a leg 21 extending generally perpendicularly from bearing bar 18 to a flange 23 (FIG. 2) and a bearing surface 26 on flange 23, as best shown in FIG. 3. Base plate 114 has a bottom surface 120 which bearing surface 26 engages to define a pivot point for actuator 10 (FIGS. 2 and 4). 
     Bearing bar 18 extends between fulcrum hook 20 and a connector 28 (FIG. 2). Bearing bar 18 also has a bearing surface 30 which engages pin 112 for applying pressure to and depressing the pin, releasing the height adjustment mechanism for adjusting the chair height. Fulcrum hook 20 and bearing bar 18 are preferably formed from a thirty-three percent glass filled nylon plastic material. 
     Connector 28 is adapted to engage and lock with a corresponding connector tang 32 which extends from fulcrum block 16 (FIG. 2). Connector 28, which defines an aperture through bearing bar 18, has a series of biased teeth or barbs 34 formed within the aperture. Tang 32 has a corresponding series of opposing or oppositely directed biased teeth or barbs 36 for cooperation and engagement with teeth 34 of connector 28. Tang 32 can be easily inserted into connector 28 because of the bias of teeth 34,36. However, tang 32 can not be withdrawn from connector 28 because of the engagement of teeth 36 with teeth 34 and the bias of teeth 34,36. 
     Fulcrum block 16 is preferably formed of a thirty-three percent glass filled nylon plastic. Block 16 has two fulcrum shoulders or pivot portions 38 on either side of tang 32 which define a pivot. Each fulcrum shoulder 38 has a generally wedge shape as shown, with the actual bearing point of the fulcrum being defined by the apex of each fulcrum shoulder 38. Tang 32 extends through aperture 116 of base plate 114 so that fulcrum shoulders 38 engage bottom surface 120 of base plate 114 (FIGS. 2 and 3). The point of engagement between shoulders 38 and bottom surface 120 defines pivot seat 22. Fulcrum block 16 also has a cavity 40, opposite to tang 32 for receiving one end of handle portion 14 (FIG. 2). 
     Handle portion 14 is preferably a stamped steel flat bar which is dimensioned suitably and formed of an alloy suitable to accommodate the moment forces generated by a user manipulating handle grasp 12. Handle portion 14 is most preferably formed from three-sixteenths inch by one-half inch chromium steel flat bar. Handle portion 14 also has a connector tang 42 formed at one end and dimensioned for a force fit with cavity 40, in fulcrum block 16. Handle grasp 12 is preferably injection molded with thermoplastic material, most preferably polypropylene. A mounting cavity 46 is molded into handle grasp 12 and dimensioned for a force fit with end 44 of handle portion 14. 
     Actuator 10 is assembled by forcing end 44 of handle portion 14 into cavity 46 of handle grasp 12. Connector tang 42 of handle portion 14 is forced into cavity 40 of fulcrum block 16. Flange 23 of fulcrum hook 20 is inserted through aperture 118 of base plate 114 so that bearing bar 18 is positioned to overlay control button 112 with bearing surface 30 in contact with the control pin. Connector tang 32 of fulcrum block 16 is inserted through aperture 116 in base plate 114 and further through connector 28 of bearing bar 18 so that teeth 36 engage teeth 34, locking fulcrum block 16 to bearing bar 18. 
     In operation, pressure may be exerted on control button 112 and the control button depressed to release the seat height control mechanism for adjustment of seat height by lifting handle grasp 12 (FIG. 3). As handle grasp 12 is lifted, shoulders 38 of fulcrum block 16 bear against bottom surface 120 of base plate 114, causing a pivot action about pivot seat 22 whereby bearing bar 18 moves in a direction generally opposite to handle grasp 12. The force exerted in manipulating handle grasp 12 in an upward direction is transferred through the contact between bearing surface 30 of bearing bar 18 to depress the control pin and release the height adjustment mechanism. 
     The seat height adjustment mechanism may also be released by manipulation of handle grasp 12 in a downward direction to apply force to control button 112, depressing the control button and releasing the height adjustment mechanism (FIG. 4). As handle grasp 12 is manipulated in a downward direction, bearing surface 26 of second fulcrum hook 20 bears against bottom surface 120 of base plate 114 defining a pivot point about which actuator 10 and specifically bearing bar 18 rotate. Bearing bar 18 moves in the same general direction as handle grasp 12 and handle portion 14. The force manipulating handle grasp 12 in a downward direction is transferred through the contact between bearing surface 30 of bearing bar 18 and the control button 112, to depress the control button and release the height adjustment mechanism. 
     While the present description of the invention is with regard to upward and downward movements in a vertical plane, it is understood that the embodiment shown in the drawings and described above is merely for illustrative purposes and is not intended to limit the scope of the invention. It is possible to rotate the plane of reference whereby backward and forward motions or side to side motions are generated in a horizontal plane for example. The actuation could pull or push a cable or secondary lever actuating devices, for example, instead of the button device or release pin specifically referred to above. 
     The above description is considered that of a preferred embodiment only. The invention and the scope of the invention are defined by the following claims as interpreted according to the principles of patent law.