Abstract:
A height adjustable chair has an upper portion that moves relative to a lower portion. Push-off arm rests are provided so that a person need not leave the chair to adjust the seat height upwardly. A seated person can transfer their body weight to the push-off arm rests supported directly by the stationary lower portion while the seat is being adjusted upwardly.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   The subject application claim the benefits of U.S. Provisional Application Ser. No. 60/513,787, filed Oct. 23, 2003 and U.S. Provisional Application Ser. No. 60/513,788, filed Oct. 23, 2003. These applications are herein incorporated by reference in their entirety. 

   BACKGROUND OF THE INVENTION 
   Height adjustable work chairs are standard in today&#39;s seated workplace environments. The most common height adjustment mechanism for work chairs utilizes a spring driven mechanism, most commonly, the locking gas spring. Since a spring driven height adjustment mechanism only powers the chair seat upwardly when the chair user reduces downward force to the spring which supports the chair seat, the maneuver for current chair design requires the chair user&#39;s legs to lift the chair user from the chair seat while the chair user awkwardly reaches with one hand to locate and lift an unmarked height adjustment lever which is usually located out of user&#39;s visual range, fashionably concealed beneath the chair seat. This puts the chair user in an awkward position, especially in a way that relates to positioning her or his height to a specific work task. And typically, the height adjustment lever is mixed in with other visually concealed and unmarked adjustment levers used to adjust seat tilt or backrest tilt, oftentimes occasioning the user to actuate the wrong lever. There is a need for some chair users performing certain tasks to adjust the height of their chair while remaining in a stable focused position on the chair. In a multiple user situation where several users share usage time on the same chair, the multi-user chair would need to be height adjusted for users of different body measurements. If, for example, the multi-user chair were used in a laboratory setting to seat multiple users at a microscope, it may sometimes be necessary for a user to adjust the height of the chair to obtain appropriate eye level for the ocular setting due to limitations of the ocular setting on the microscope. With chairs currently available, the awkward maneuver required for adjusting the height of the chair upwardly, more or less necessitates that the user speculate how far up to adjust the chair while employing trial and error to obtain the sought after adjustment. This current method usually requires more than one attempt to get it right. In other laboratory uses, when high stool type chairs are used to seat laboratory workers at counter height work surfaces, the chair needs to be adjusted at a height that oftentimes suspends a worker&#39;s feet above the floor rendering the worker unable to push her or his weight off the chair seat for further upward height adjustment. In this situation, the worker must jump off the chair, and while standing, adjust the chair upward, speculating at the needed height adjustment. Then the worker must climb back on the chair to see if the adjustment was on target, many times having to readjust the chair a second or third time. In office settings, this same inefficiency with current chair designs exists, but is less noticeable due to lesser functional requirements demanded by the work task, or by the worker. In various work settings height adjustable chairs allow a number of workers to use a specialized piece of equipment such as a drill press or assembly line machinery. Efficient upward height adjustment is not only necessary for worker efficiency, but also to allow the worker accurate adjustment of user&#39;s working height appropriate to the work equipment. In situations where chair height adjustment is needed, the most efficient and accurate upward adjustment of chair height is while the user is in the chair. An alternative for achieving the benefits of this invention would be the use of an expensive electric powered chair, attendant with power consumption costs, and the necessity of spatial support requirements related to power cord and/or battery weight, and battery recharging paraphernalia. There is a need for a relatively inexpensive height adjustable chair that provides a seated worker upward chair height adjustment while the worker remains as suitably disposed in the chair as possible to the work task to which the adjustment is being made. 
   All patents, patent applications, provisional patent applications and publications referred to or cited herein, are incorporated by reference in their entirety to the extent they are not inconsistent with the explicit teachings of the specification. 
   SUMMARY OF THE INVENTION 
   The invention involves height adjustable work chairs from which seated persons need not remove their body weight from the chair during upward height adjustment, that with current chair designs, would awkwardly position the person relative to the task to which the adjustment is being made. Push-off arm rests can support all or part of a user&#39;s weight independent of the height adjustment mechanism, allowing the chair seat to be adjusted upwardly. The chair has an upper portion that moves relative to a lower stationary portion supported on the floor. The push-off arm rests are directly connected to the lower portion allowing the body weight of the chair user to be transferred from the chair seat to the floor in a way that reduces downward force to the height adjustment mechanism without the necessity of user&#39;s feet depending contact with the floor surface, as is the requirement with current chair designs. In the most preferred embodiment, a remote actuation mechanism is mounted proximate one of the push-off arm rests which allow the chair user to actuate a spring loaded height adjustment mechanism while at the same time using the push-off arm rests to transfer user&#39;s body weight away from the spring loaded height adjustment mechanism which can then resiliently power the chair set upwardly. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  shows a side view of a preferred embodiment of the height adjustable work chair of the subject invention. 
       FIG. 2  shows a front view of the height adjustable work chair shown in  FIG. 1 . 
       FIG. 3  shows a side view of the height adjustable work chair shown in  FIG. 1  where the chair seat position has been adjusted upward. 
       FIG. 4  shows a front view of the height adjustable work chair shown in  FIG. 3 . 
       FIG. 5  shows another preferred embodiment of the height adjustable work chair of the subject invention with height adjustable push-off arm rests. 
       FIG. 6  shows another preferred embodiment of the height adjustable work chair of the subject invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Push-off arm rests allow a seated person to remove their weight from the chair seat so the position of the seat can be adjusted without the seated person having to stand or leave the chair. 
   A preferred embodiment of the height adjustable work chair is shown in  FIGS. 1–4 . The height adjustable work chair of the subject invention has a push-off arm rest which allows one seated on the chair to lift their weight off the chair seat so the seat can be raised. The chair has an upper portion  10  and a lower portion  12 . The upper portion moves relative to the lower portion. The lower portion  12  includes a floor contacting base  14 . In the exemplified embodiment, the base  14  has castors  16 . The upper portion  10  moves relative to the lower portion  12  by a height adjustment mechanism  18 . The height adjustment mechanism is supported by the base  14  and supports a seat support mechanism  20  which supports the seat  22  of the chair. The seat support mechanism  20  and the chair seat  22  move relative to the lower portion and therefore are part of the upper moving portion of the subject height adjustable chair. The upper portion  10  can further include a seat back  24  and arm rests  26 . 
   Push-off arm rests allow the body position of a person seated in the chair to be changed while the person&#39;s full body weight is supported by the height adjustable work chair. A push-off arm rest supporting mechanism is attached to the lower portion  12  of the chair. The push-off arm rest supporting mechanism  28  includes push-off arm rest supports  30 ,  32 . A first end  34 ,  36  of each support  30 ,  32 , respectively, is connected to the lower portion  12 . A second end  38 ,  40  of each support  30 ,  32  has push-off arm rests  42 ,  44 . The push-off arm rests remain stationary with the lower portion of the chair as the upper portion rises. In a particularly preferred embodiment, the push-off arm rests are height adjustable. The push-off arm rest supports  30 ,  32  allow the push-off arm rests  42 ,  44  to be adjusted relative to the push-off arm rest supporting mechanism  28  ( FIG. 5 ). Additionally, the push-off arm rest supporting mechanism  28  can be detachable. Slots  46  allow upper portion components attached to the push-off arm rest supports to move as the upper portion rises. A swivel  48  allows the chair to rotate at any position. 
   Height adjustment mechanisms can be any suitable device that can move the upper portion relative to the lower portion. Examples include, but are not limited to, springs, telescoping supports, gas springs, and locking gas springs. In the embodiment shown in  FIG. 5 , a locking gas spring  54  supported by a stand tube  56  is actuated by contacting and moving an actuation button  58 . 
   In the embodiment shown in  FIGS. 1–4 , an actuation mechanism  50  controls movement of the upper portion  12  relative to the lower portion  10 . The actuation mechanism  50  can be any type suitable to control the height adjustable mechanism. In this embodiment, the height adjustable mechanism is a telescoping support with an upper section and a lower section which move in parallel alignment and can be locked into position. The actuation mechanism  50  controlling movement of these sections is a remote activating device using a lever and cable. An additional actuator  52  is shown on the chair in  FIG. 1  and controls the tilt and positioning of the seat  22  and seat back  24 . 
     FIG. 6  shows another preferred embodiment of the height adjustable chair of the subject invention. The chair (U.S. Pat. Nos. 6,439,657 and 6,702,372) includes an upper portion  10  that moves relative to a lower portion  12 . The upper portion includes a seat support mechanism  20 , a chair seat  22  and a seat back  24 . The lower portion includes a base  14  on castors  16  and a pivoting knee pad  60 . The push-off arm rests have a remote actuator  50  and are connected to the lower portion  12 . 
   It is understood that the foregoing examples are merely illustrative of the present invention. Certain modifications of the devices and/or methods employed may be made and still achieve the objectives of the invention. Such modifications are contemplated as within the scope of the claimed invention.