Abstract:
A chair tilting control having a bracket connectable to a seat and a bracket connectable to a base, the base bracket being entirely within the seat connector bracket and having a pair of elongated flat spring bars urging the seat connector bracket against the base connector bracket to the no-tilt condition, and a manually operable spring adjustment screw or lever driving a cam follower to increase or decrease the non-tilting action of the spring.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates generally to chair controls, and more particularly to a vary compact chair control of neat appearance. 
     2. Description of the Prior Art 
     Many chair controls are known in the art. They involve a variety of sizes and shapes and mechanisms. A reference to any specific number of patents in this art could be misleading because of the possible omission of some other chair control which someone might consider relevant. One control of which we are aware and which was a step in the direction of attractive design and compact construction is shown in U.S. Pat. No. Des. 213,494. 
     Despite the many efforts toward simplified, more reliable, inexpensive, and attractive chair controls, further improvement was needed and the result is the present invention. 
     SUMMARY OF THE INVENTION 
     In a typical embodiment of the present invention, a chair control assembly has a base connector and a seat connector pivoted thereto on a horizontal axis. Between the base and seat connector there is at least one spring member which is adjustable by a manually operated member to increase or decrease the spring force urging the seat connector against the base connector in a non-tilting, stop direction. Different embodiments employ different adjusting means and the preferred spring is a flat bar-type elongated spring leaf member. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevational view of a chair assembly using a chair tilting control assembly according to a typical embodiment of the present invention. 
     FIG. 2 is a fragmentary top plan view of the control assembly with portions broken away to show interior details. 
     FIG. 3 is a section therethrough taken at line 3--3 in FIG. 2 and viewed in the direction of the arrows. 
     FIG. 4 is a section through a portion of the cam formed in the seat connector portion, the section being taken at the line 4--4 in FIG. 2 and viewed in the direction of the arrows. 
     FIG. 5 is a side view of the spindle connector bracket itself. 
     FIG. 6 is a front view of the assembly of the spindle connector bracket and spring mounting bracket. 
     FIG. 7 is a bottom view of an alternate embodiment of the control assembly. 
     FIG. 8 is a side, partially sectioned, view of the alternate embodiment. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawings in detail, FIG. 1 shows a chair assembly 5 with seat 6, base 7 and spindle 26. The chair tilting control assembly 8 includes the seat connector bracket 11 (FIG. 2), horizontal pivot pin 12, and the base connector bracket assembly 13. The base connector bracket assembly includes a spindle connector bracket 14 and the spring mounting bracket 16 secured thereto. As is better shown in FIG. 5, the spindle connector bracket has a pair of notches 17 in the upper marginal edge, and the spring mounting bracket has a pair of lugs such as 18, one at each side, and which are received and located in these notches. Also, the spring mounting bracket has a plurality of tabs 19 therein which are received in slots 21 in the front upturned flange of the spindle connector bracket. 
     Pivot or hinge pin 12 is received in the upturned flanges at the sides of the spindle connector bracket, and is also received in the downwardly turned side flanges of the seat connector bracket and is retained in place by a push-on nut 22. Suitable spacers 23 can be provided between the downturned flanges of the seat connector bracket and the upturned flanges of the spindle connector bracket. 
     The assembly 13 is secured on the spindle 26 by forcing the assembly downwardly on the tapered surface 27 of the spindle, and downturned annular flange 28 of the spindle mounting bracket, and the downturned annular flange 29 of the spring mounting bracket, being thereupon snugly and securely affixed to the spindle. 
     In the illustrated embodiment, two spring bars 31 and 32 are employed. Each of these is mounted as bar 31 is mounted, by means of a pin 33 received through an aperture in the front end of the spring mounting bracket, the spring passing rearwardly therefrom through the aperture 34 in the spring mounting bracket, and toward the rear of the seat connector bracket, where the rear edge 36 of the spring bar is immediately in front of the rear downturned flange 11R of the seat connector bracket. A generally U-shaped rod 37 is received in a nut 38, the central portion 37C being received in the upwardly opening slot 39 in the nut, and the outboard portion 37D of the bar being received on top of the rear end of the spring bar. 
     The nut 38 is received on an adjustment screw 41 which is received through an aperture 42 in the rear downturned flange 11R of the seat connector portion, and a front downturned tab 43 is apertured to receive the front end mounting portion 44 of the screw therethrough, this being stepped down so that the front shoulder 46 of the screw rests against the tab 43, and a washer 48 retained by a snap ring 49 in the groove at the front of the screw, retains the screw longitudinally in the tab 43. The nut 38, being threadedly received on the screw, can be advanced toward the front of the control assembly in the direction of arrow 51, or retracted toward the rear of the assembly in the direction of the arrow 52. 
     The front end of the spring bar 31 abuts the underside of the spring mounting bracket at 53. The rear end of the spring bar abuts the outboard portion of the bar 37 which, in turn, abuts the underside of the seat connector bracket at 57. The midportion of the spring is supported on the spring mounting bracket at the bottom edge 54 of the aperture in the rear wall 56 thereof. Edge 54 is high enough to cause an upward bow in the center of an otherwise flat spring bar. Therefore the rear end of each spring urges the seat connector bracket in the direction of the arrow 58, so that the underside of the front portion thereof abuttingly engages the upper edge of the upturned flange 59 of the spindle connector bracket at 61, this being the non-tilt condition. Then, if the user of the seat mounted on top of the seat connector bracket leans back, the seat will tilt about pivot pin 12 in the direction of the arrow 62, thus increasing the spring return force as the tilting motion separates the underside of the front portion of the seat connector bracket from the upper edge 61 of the spindle connector bracket. 
     To increase the resistance of the assembly to tilting, the adjustment screw 41 is turned by means of the handle 63 thereon to drive the screw in rotation and thereby drive the nut 38 forward in the direction of arrow 51. As this occurs, the cam surface 65, which is formed in the top of the seat connector bracket, and which is inclined downwardly toward the front of the unit, urges the outboard portion 37D of the cam follower bar downward and away from the seat, thus increasing the spring bias in the spring bar as it is bowed to a greater degree about the fulcrum edge 54 in the spring mounting bracket. Accordingly, the resistance of the seat to tilting is increased. Turning the adjustment screw in the opposite direction achieves the opposite result. 
     The overall height of the unit is not affected as the adjustment is made, nor does the adjustment screw extend further out of or recede further into the unit. Thus, the very compact configuration remains the same, and the overall height of the unit itself can be kept at approximately one inch. Typically the spring bars are made of fiberglass, and the seat connector bracket, spring mounting bracket, and spindle connector bracket are made of formed sheet metal. The other components can also be made inexpensively of readily available, but reliable, materials. 
     Referring now to the alternate embodiment, the spring members are mounted in the same way as in the first described embodiment. However, a guide rod 66 is received through the aperture in the downturned tab 43 and passes through the aperture 42 in the rear wall 11R of the seat connector bracket, the rod having a head 67 thereon. A detent rail 68 has a front leg 69 and rear leg 71, both of which are apertured and received on the rod 66. The rod has a stop ring 72 received in a groove at the front end thereof whereby the rod is retained in assembly with the tab 43, rear wall 11R of the seat mounting bracket, and the two flanges 71 and 72 of the detent rail 68. 
     The lower edge of the detent rail has a series of downwardly projecting teeth 73 therein which receive the upwardly turned detent lug 74 of the adjustment handle 76 which is pivotally mounted at 77 to the seat connector bracket. The outer end of the lever 76 has a protective boot 78 thereon and can be pulled and pushed by the operator to pivot the lever 76 about the axis 77 and thus slide the cam follower mount block 38A along the rod 66. The block has a downwardly projecting pin 79 thereon received in the slot 81 of the operating lever, the pin and lever being retained together by a stop ring 82 received in a slot in the pin 79. The rings 82 and 72 may be of the Waldes-Kohinoor type, for example. The block 38A has a cam follower bar 37 mounted therein in the same manner as in the previously described embodiment, and thus functions in much the same way, except that it is operated by the lever rather than by a hand screw. 
     The spring 83 between the lever 76 and the stop ring 82, facilitates the movement of the lever detenting lug 74 along the downwardly facing teeth of the detent rail 68, but urges the lug up into the notches at all times so that any particular lever adjustment will be reliably maintained. 
     Because of the novel construction according to the invention, the overall height of the control assembly can be as little as one inch. The overall height is typically from 1.0 to 1.2 inches, &#34;D&#34; in FIG. 3.