Tilt-swivel Mechanism For A Chair

Abstract

A tilt-swivel mechanism for a chair. The tilt-swivel mechanism includes a vertical shaft journaled for rotation within the base or column of the chair. The upper end portion of the shaft carries a mounting plate and a dish shaped upper plate is secured to the bottom pan of the chair seat and is hinged to the mounting plate so that the upper plate, as well as the seat, can pivot about the hinge pin. A resilient block of rubber or plastic material is located between the bottom surface of the upper plate and a cap secured to the upper end of the shaft. As the seat tilts rearwardly, the bottom surface of the upper plate pivots upwardly to compress the resilient block against the cap and cushion the tilting action.

Description

BACKGROUND OF THE INVENTION

Many chairs incorporate a tilt-swivel mechanism which not only enables the chair to swivel or rotate with respect to the base but also to tilt or pivot rearwardly. To cushion the tilting action and provide a return to the upright position, a spring assembly is normally utilized with the chair. In one common form of tilt-swivel mechanism coil springs are utilized for this function. To provide the necessary cushioning action, a coil spring of substantial length would normally be required, and thus in order to decrease the overall length of the spring, it is common practice to employ a pair of side-by-side coil springs. The use of the coil springs in the conventional tilt-swivel mechanism detracts from the appearance of the chair for the springs are readily visible, and occasionally clothing or stockings may catch on the exposed springs or spring supports. To camouflage the springs, the springs are often painted the color of the chair base, while in other cases the springs are enclosed in housings or shields. As a further disadvantage, the use of coil springs requires occasional lubrication to prevent squeaking and adjustment of the spring force.

In some instances rubber cushions or pads have been utilized in place of the coil springs, and the most common form of rubber cushion is a cylindrical cushion substituted for the conventional coil spring. However, the use of rubber cushions of this type results in a rather unattractive appearance for the chair in that the elongated rubber cushion or its casing is visible to the observer.

SUMMARY OF THE INVENTION

The invention relates to an improved tilt-swivel mechanism for a chair. The tilt-swivel mechanism includes a vertical shaft journaled for rotation within the base of the chair, and the upper end portion of the shaft carries a mounting plate. Hinged to the mounting plate for tilting movement is a dish shaped upper plate which is secured to the bottom pan of the chair seat. With the hinge construction, the upper plate and chair seat can tilt in a front-to-rear direction with respect to the shaft and base of the chair.

To cushion the tilting action, a pair of resilient rubber-like blocks are located between the bottom surface of the upper plate and a cap secured to the upper end of the shaft. As the seat tilts, the bottom surface of the upper plate pivots upwardly to compress the block against the cap and cushion the tilting action.

The tilt-swivel mechanism of the invention is a compact unit in which the resilient cushioning blocks are not exposed and are located entirely within the upper, dish shaped mounting plate.

As the use of the resilient blocks eliminates the conventional coil springs, the need for lubrication is eliminated and there is no necessity for readjusting the cushioning force due to wear or fatigue as is required with coil springs.

As a further advantage, the tilt-swivel construction has a fewer number of parts than conventional tilt-swivel mechanisms and thereby has a lower cost.

DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a side elevation of a chair incorporating the tilt-swivel construction of the invention;

FIG. 2 is an enlarged side elevation of the tilt-swivel mechanism with parts broken away in section;

FIG. 3 is a view similar to FIG. 2 showing the chair seat in a tilted condition and the rubber blocks compressed, and

FIG. 4 is a section taken along line 4--4 of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 illustrates a chair having a base 1 and a seat 2 which is connected to the base through a tilt-swivel mechanism, indicated generally by 3.

As illustrated in FIGS. 2 and 3, the tilt-swivel mechanism 3 includes a vertical shaft 4, which is mounted for rotation within a bushing 5 in the base 1. Secured to the upper portion of the shaft 4 is a mounting plate 6 which includes a generally flat bottom section 7 and upwardly sloping side edges 8. Ears 9 extend upwardly from the sloping side wall 8 and are provided with aligned openings.

An upper plate 10 is secured to the seat 2 and is mounted for tilting movement with respect to the plate 6. As shown in FIG. 2, the upper plate 10 is provided with a peripheral flange 11 which is secured to the bottom pan of seat 2 by screws or other fasteners. The mounting plate 10 has a generally dish shaped configuration including a downwardly sloping sidewall or body 12 which terminates in a bottom surface 13. Bottom surface 13 is provided with an elongated opening or slot which receives the shaft 4.

To hinge the plate 10 to the mounting plate 6, a hinge pin 14 is secured to the body portion 12 of plate 10, and the ends of the hinge pin project through openings in the body portion 12 and are journaled within the openings in ears 9.

To limit the forward tilting movement of the upper plate 10 and seat with respect to the mounting plate 6, a resilient bumper 15 is utilized. The bumper 15 includes an upper enlarged head 16 and a stem 17, which is secured with an opening in the sloping wall 8 of the mounting plate 6. As the upper plate 10 tilts forwardly, the body portion 12 engages the head 16 of the bumper to limit the forward tilt.

To cushion the rearward tilting action, a pair of resilient blocks 18 are located between the bottom surface 13 of plate 10 and an annular cap 19 secured to the upper end of shaft 4. The bottom surface 13 of plate 10 is provided with a pair of recesses 20 which serve to position the blocks 18 on either side of the shaft 4. In addition, the cap 19 is provided with a downwardly extending rear flange 21 which engages and aligns the rear edges of the blocks 18.

To fabricate the tilt-swivel mechanism of the invention, after attachment of the upper plate 10 to the mounting plate 6 through the hinge pin 14, the resilient blocks 18 are positioned on the bottom surface 13 of the upper plate. The cap 19 is then inserted around the upper end of the shaft and forced downwardly, thereby compressing the blocks. With the blocks in a compressed condition, the upper end of the shaft 4 is upset or swaged outwardly by a staking action to thereby firmly secure the cap to the upper end of the shaft 4.

As the shaft 4 is journaled within the socket 5 in the base, the shaft and seat can rotate freely around the axis of the shaft 4.

When the seat 2 is tilted rearwardly about the axis of the hinge pin 14, the lower surface 13 of the upper plate 10 will pivot upwardly, thereby further compressing the blocks 18 against the fixed cap 19 to cushion the tilting action. When the tilting force is removed, the resiliency of the blocks 18 will urge the upper plate 10 and seat 2 to the original upright position.

While the drawings illustrate two generally cubical blocks 18 being utilized, it is contemplated that the blocks can take any desired configuration, such as cylindrical, sperical, oval or the like. Similarly, while the drawings show two blocks being utilized, it is contemplated that a single annular block can be employed which surrounds the shaft 4, or a series of separate blocks can be spaced around the shaft 4.

The tilt-swivel mechanism of the invention is a compact unit, and as the resilient cushioning blocks 18 are located within the upper plate 10, they are not exposed so that the tilt-swivel mechanism has a more pleasing outer appearance than conventional types using coil springs or other rubber cushioning members.

The tilt-swivel mechanism has a fewer number of parts than conventional tilt-swivel mechanisms, thereby reducing the overall cost of the unit.

While the above description has been directed to a tilt-swivel chair, it is contemplated that the tilt mechanism can also be utilized in a non-swivel type of seating such as used in theaters, airports, multiple chair units for reception rooms, and the like.

Various modes of carrying out the invention are contemplated as being within the scope of the following claims, particularly pointing out and distinctly claiming the subject matter which is regarded as the invention.

Claims

I claim

1. A tilt-swivel mechanism for a chair to enable the seat of the chair to swivel as well as tilt to the rear, comprising a supporting structure, a vertical shaft journaled for rotation about its axis with respect to said supporting structure, a mounting plate secured to said shaft and spaced below the upper end of the shaft, an upper dish-shaped annular support member located above said mounting plate, a chair seat secured to said upper support member, said upper support member having a peripheral portion secured to said chair seat and having a central body portion extending downwardly from said peripheral portion and terminating in a generally flat bottom surface spaced beneath said chair seat, said bottom surface having a single operative opening to receive said shaft, hinge means for hinging the upper support member to said mounting plate to enable the upper support member and said chair seat to tilt to the rear, abutment means secured to the upper end of the shaft and located above the bottom surface of said upper support member, and resilient means disposed and held between said abutment means and the bottom surface of said upper support member whereby said resilient means is concealed by said dish-shaped support member, rearward tilting of said chair seat acting to pivot said bottom surface upwardly and compress said resilient means against said abutment means to cushion the tilting action.

2. The structure of claim 1, wherein the bottom surface of said upper support member is provided with an upwardly facing recess to receive said resilient means.

3. The structure of claim 1, and including a resilient bumper interposed between the mounting plate and said bottom surface and located on the opposite side of said shaft from hinge means, said bumper disposed to prevent contact between said upper support member and said mounting plate when the chair seat is in a non-tilted position.

4. The structure of claim 1, wherein said abutment means includes a surface extending radially outward from the shaft and engaged with the upper end of said resilient means, and said abutment means also includes a downwardly extending member engaged with the rear end of said resilient means.

5. A tilt-swivel mechanism for a chair to enable the seat of the chair to swivel as well as tilt to the rear, comprising a supporting structure, a vertical shaft journalled for rotation about its axis with respect to said supporting structure, a mounting plate secured to said shaft and spaced below the upper end of the shaft, an upper annular support plate located above said mounting plate, a chair seat secured to said upper support member, said upper support member having a peripheral portion secured to said chair seat and having a central body portion extending downwardly from said peripheral portion and terminating in a bottom surface spaced beneath said chair seat, said bottom surface having an opening to receive said shaft, hinge means for hinging the upper support member to said mounting plate to enable the upper support member and said chair seat to tilt to the rear, abutment means secured to the upper end of the shaft and located above the bottom surface of said upper support member, and resilient means disposed between said abutment means and the bottom surface of said upper support member, rearward tilting of said chair seat acting to pivot said bottom surface upwardly and compress said resilient means against said abutment means to cushion the tilting action, said resilient means including a pair of resilient members of rubber-like material located laterally with respect to the fore and aft direction of tilt of said seat on opposite sides of said shaft.

6. The structure of claim 5, wherein each resilient member is generally cube-like in shape.