Compound stool with energy storing spring

Abstract

A compound stool provides a base supporting a seat structure for limited vertical motion with an energy storing spring communicating between the base and seat structure to bias the seat structure upwardly but allow its motion downward relative to the base. The seat structure moves downwardly responsive to a user's weight as the user is seated to store energy generated in the spring by its compression. The spring releases stored energy as the user exits from the stool to aid the user's exiting motion. The base provides auxiliary wheels for locomotion and peripheral supports to aid a user's motion in entering and exiting the stool. The seat structure may be locked in lowermost position, once attained by a user's weight thereon.

1 . A compound stool having a seat structure vertically movable relative to a supporting base responsive to a user's weight on the seat structure to store kinetic energy in a spring to aid users entry on and exit from the stool, comprising in combination: 
 a peripherally defined conic base having a truncating top and a bottom disk to define a medial base chamber;    seat structure having an uppermost seat disk with at least three spacedly arrayed depending support shafts extending for slidable motion through seat support holes defined in the truncating top of the base and extending into the medial base chamber to communicate with an upper spring plate in the medial base chamber; and    spring structure including a compression spring between the upper spring plate and the bottom disk to bias the upper spring plate to an upward position in the medial base chamber but allow motion of the upper spring plate downwardly against spring structure bias responsive to weight of a user on the seat disk.    
   
   
       2 . The compound stool of  claim 1  further comprising: 
 the truncating top of the base supporting a seat stop disk spacedly thereabove and beneath the seat disk, said seat stop disk defining a fastener slot and pivotally carrying therebeneath a fastening lever having a fastening finger movable beneath the fastening slot; and    the seat disk carrying a depending fastener having a lowermost fastening ring to move vertically through and below the fastening slot defined in the seat stop disk for selective fastening beneath the seat stop disk responsive to pivotal motion of the fastening lever to positionally maintain the seat disk from upward motion position relative to the base.    
   
   
       3 . The compound stool of  claim 1  further comprising: 
 at least three Z-shaped wheel brackets having lower horizontal arms supported on the bottom disk, medial arms extending spacedly upwardly adjacent the circumferential outer surface of the base and upper horizontal arms extending radially outwardly from the base to carry depending wheels having coplanar lower surfaces spacedly below the base,    said wheel brackets having resilience to allow the upper horizontal arms to move upwardly responsive to the weight of a user on the seat disk to move the wheels upwardly to a position at least coplanar with the base to support the base for positional maintenance on an underlying supportative surface.    
   
   
       4 . The compound stool of  claim 1  further comprising user support structure carried by the base, comprising: 
 similar diametrically opposed fastening plates supported on the lower surface of the bottom disk to extend radially outwardly therefrom;    similar upstanding loop structures carried by each fastening plate to extend upwardly therefrom and spacedly above the seat.    
   
   
       5 . The compound stool of  claim 1  having means for maintaining the compression spring in axial alignment with the axis of the truncated conic base.  
   
   
       6 . The compound stool of  claim 1  further comprising: 
 a spring bottom support disk carried spacedly above the bottom disk to support the compression spring thereabove, and    support means communicating between the spring bottom support disk and the bottom disk for adjustable vertical positioning of the spring bottom support disk relative to the bottom disk to regulate compression in the compression spring.    
   
   
       7 . The compound stool of  claim 1  wherein the compression spring comprises a wound wire spring of right circular cylindrical configuration.  
   
   
       8 . A compound stool having seat structure vertically movable relative to a supporting base responsive to a user's weight on the seat structure to store kinetic energy in a spring to aid user entry on and exit from the stool, comprising in combination: 
 a peripherally defined conic base having a truncating top and a bottom disk to define a medial base chamber, said base having 
 at least three Z-shaped wheel bracket having lower horizontal arms supported on the undersurface of the bottom disk, medial arms extending upwardly adjacent the circumferential outer surface of the base and upper horizontal arms extending radially outwardly from the base to carry depending castor wheels having coplanar lower surfaces extending spacedly below the base, said wheel brackets having sufficient resilience to allow the upper horizontal arms to move angularly upwardly responsive to the weight of a user on the seat structure to move the castor wheels upwardly to a position at least not below the base to positionally maintain the base on an underlying supportive surface, and  
 the truncating top of the base supporting a seat stop disk spacedly thereabove, said seat stop disk defining a fastener slot and pivotally carrying therebenath a fastening lever to selectively move an elongate fastening finger defined by the fastening lever beneath the fastening slot;  
   a seat structure having an uppermost seat disk with at least three spacedly arrayed depending support shafts extending for slidable motion through support shaft holes defined in the truncating top of the base and into the medial base chamber to carry an upper spring plate in the medial base chamber, said seat disk 
 carrying a depending fastener having a lowermost fastening ring movable through and downwardly below the seat support stop disk for selective fastening beneath the seat disk responsive to motion of the fastening lever to positonally maintain the seat disk in a vertical position relative to the base; and  
 spring structure including a circularly cylindrical compression spring between the upper spring plate and a spring bottom support disk carried spacedly above the bottom disk to bias the upper spring plate to an upward position in the medial base chamber but allow motion of the upper spring plate downwardly against compression spring bias responsible to weight of a user on the seat disk.  
   
   
   
       9 . The compound stool of  claim 1  further having: 
 support means communicating between the spring bottom support disk and the bottom disk for adjustable vertical positioning of the spring bottom support disk relative to the bottom disk to regulate compression in the compression spring,    said support means including at least three bolts extending upwardly through the bottom disk, carrying a first nut between the bottom disk and the spring bottom support disk, extending in threaded engagement through a second nut immovably carried by the spring bottom support disk and spacedly above the spring bottom support disk.