Patent Publication Number: US-6209843-B1

Title: Pivotal rocking chair base

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention herein pertains to a chair base and particularly to a chair base which provides both pivotal and rocking action. 
     2. Description of the Prior Art and Objectives of the Invention 
     It is usual in the furniture industry to provide a chair base which will allow the chair to rotate horizontally and to rock or tilt. Such chair bases have been produced for many years as illustrated in U.S. Pat. No. 4,025,020. These chair bases include coil or other springs to allow rocking while a center axis defines the rotational motion. Such chair bases are in widespread use by furniture manufacturers. Oftentimes a commercial customer will require the manufacturer to rigidly affix the rocker assembly or horizontal swivel mechanism to prevent either the rocking or rotational movement and sometimes both. This has generally been carried out in the past by welding braces or supports to rigidly affix the chair base. While such measures do serve the intended purposes, consumers often demand a more versatile chair, namely one that they can adjust and change as desired rather than one which has been permanently modified. Thus a chair owner may wish to cease all horizontal rotational movement, yet enjoy the rocking motion. Another chair owner may desire to set a particular tilt to the chair but allow the rotational movement to be free and unencumbered. 
     Thus for the more demanding consumer the present invention was conceived and one of its objectives is to provide a pivotal rocking chair base which can be easily, manually adjusted and its motion selectively limited. 
     It is still another objective of the present invention to provide a chair base in which the horizontal rotational movement can be stopped while allowing the tilting or rocking motion to continue unabated. 
     It is yet another objective of the present invention to provide a chair base which will allow the user to selectively terminate the rocking motion yet allowing the rotational movement to continue. 
     It is still a further objective of the present invention to provide chair base which can be quickly and easily transformed from one of free movement to one of very limited movement manually by a consumer. 
     It is yet another objective of the present invention to provide a chair base which is relatively inexpensive to purchase and which can be manufactured at relatively low cost. 
     Various other objectives and advantages of the present invention will become apparent to those skilled in the art as a more detailed description is provided below. 
     SUMMARY OF THE INVENTION 
     The aforesaid and other objectives are realized by providing a pivotal rocking chair base for attachment to an upholstered or other chair. The chair base includes a rocker assembly having a rocker plate and a resiliently mounted base plate. The rocker assembly is pivotally attached by a central axle to a swivel plate from which legs depend. The swivel plate includes a threaded stop member which can be aligned with an aperture in the base plate of the rocker assembly. Thus by manually turning the stop member it will extend into the base plate aperture and prevent horizontal-rotational or pivotal movement of the rocker assembly. Front and rear turnbuckles affixed such as by welding or the like along the front and rear edges of the base plate allow the user to manually adjust the amount of tilt or rocking action which occurs between the base plate. The front or first turnbuckle acts as an adjustable assembly to define the minimum space between the front of the rocker plate and the front of the base plate. A second adjustable assembly or turnbuckle is rigidly affixed proximate the rear edge of the base plate which is likewise manually adjustable and can be extended or shortened, depending on the particular tilt or angle desired for the chair seat. By extending both adjustable assemblies fully, tilting and rocking action is therefore prevented. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 depicts a typical chair with the preferred pivotal rocking chair base attached; 
     FIG. 2 illustrates an enlarged side elevational view of the pivotal rocking chair b Pas shown in FIG. 1; 
     FIG. 3 demonstrates a plan view along lines  3 — 3  of FIG. 2; 
     FIG. 4 shows the chair base as seen in FIG. 2 but with the adjustable assemblies configured for a seat rear tilt; and 
     FIG. 5 features the chair base as shown in FIG. 4 but with the adjustable assemblies configured to provide the seat with a forward tilt; 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT AND OPERATION OF THE INVENTION 
     For a better understanding of the invention, turning now to the drawings, FIG. 1 demonstrates the preferred form of pivotal rocking chair base  10  attached to the bottom of seat  13  of a conventional upholstered chair  11  such as usual by bolts, screws or otherwise. As hereinbefore explained, pivotal chair bases which rock and pivot are old and are well known in the industry. However, purchasers of such chairs often desire to temporarily limit or eliminate the rocking motion as between rocker plate  15  and base plate  16  of rocker assembly  14  as shown in FIGS. 1 and 2. Also, it is not unusual for purchasers or users of chair  11  to want to prevent the horizontal rotation of such chairs in an easy, convenient but temporary manner. 
     As seen, rocker assembly  14  is pivotally attached by axle  17  to swivel plate  19  for rotational movement. Rocker plate  15  is resiliently attached to base plate  16  by resilient coil springs  20  as seen in FIGS. 2 and 3 for rocking or tilting action. Legs  21  affixed to swivel plate  19  are formed from tubular steel or other suitable materials and are affixed such as by bolting, welding or the like. As conventional, rocker assembly  14  will rotate about axle  17  and will tilt according to the particular load distribution on seat  13  as seen in FIG. 1 as resilient coil springs  20  expand, relax or contract depending on the particular load applied. 
     It is often desirable to terminate the horizontal rotational movement between rocker assembly  14  and swivel plate  19  and accordingly, preferred stop member  23  will accommodate this. Stop member  23  is threadably affixed to swivel plate  19  and when desired, the user of chair  11  can simply rotate stop member  23  and extend it upwardly, into aligned aperture  24  of base plate  16  as shown in FIG.  3 . Thus stop member  23  effectively, rigidly affixes rocker assembly  14  to swivel plate  19  when rotation is not desired. Thereafter, if rotation is again needed, stop member  23  can be manually rotated in the opposite direction, withdrawing it from aperture  24  of base plate  16  to allow rocker assembly  14  to again rotate horizontally about axle  17  as shown in FIGS. 2 and 3. 
     As further shown in FIG. 1, chair  11  can rock or be tilted by the load distribution on chair seat  13  as coil springs  20  expand and contract according to the weight distribution. Should it be desirable to prevent the rocking action or to affix the tilt in any of a infinite variety of positions such as the rearward tilt as shown in FIG. 4 or in a forward tilt as shown in FIG. 5, standard adjustable threaded turnbuckles  26 ,  27  which are rigidly affixed to the front and rear edges of base plate  16  can be selectively rotated to apply greater, lesser or zero pressure on rocker plate  15 . Thus, if a rearward tilt of chair seat  13  is desired, front turnbuckle  26  is extended as conventional while rear turnbuckle  27  is reduced in length. Should the opposite tilt of chair seat  13  be desired such as shown in FIG. 5, then front turnbuckle  26  is shortened while rear turnbuckle  27  is lengthened to provide the desired tilt. With turnbuckles  26  and  27  extended as shown in FIGS. 4 and 5, chair  11  will not rock but will remain in a tilted position until turnbuckles  26 ,  27  are shortened by appropriate manual rotational movement to positions such as shown in FIG. 1 which illustrates both turnbuckles  26 ,  27  lowered to allow seat  13  to rock and/or tilt freely. 
     Thus, pivotal rocking base  10  can be manually adjusted as desired either for pivotal or tilting action independently as desired, quickly and easily by the ultimate chair user without the need of expensive tools or equipment. 
     The illustrations and examples provided herein are for explanatory purposes and are not intended to limit the scope of the appended claims.