Patent Description:
This disclosure relates to the field of adjustable height stools. More particularly, this disclosure relates to an adjustable height stool of improved construction and aesthetics that is resistant to developing a looseness over time that results in wobbling when a user sits on the stool.

Improvement is desired in the construction of adjustable height stools. Conventional adjustable height stools have various shortcomings. For example, many height adjusting devices for these stools are designed in a way that a screw connecting a stool seat penetrates a screw hole in a stool base, and the height may be adjusted through the cooperation of the screw with the screw hole. After a long-term use, a gap between the screw and the screw hole will develop due to multiple repetitive rotational adjustments on the screw. The gap results in wobbling and other undesired movement of the screw in the screw hole.

When a user sits on the stool the weight of the user applied to the wobbling movement of the screw results in uneven stress to be applied to the small contact area of the connection site of the screw and the stool seat. As a result, the stool seat is easy to loosen and wobble, thus affecting the use reliability of the stool. This undesired wobbling of the stool can cause discomfort in sitting and can result in the user falling from the stool.

Examples of known adjustable height stools are disclosed in <CIT>, <CIT> and <CIT>.

What is desired is an adjustable height stool that is resistant to developing a looseness over time that results in wobbling when a user sits on the stool.

The present invention provides an anti-wobbling adjustable height stool as defined in claim <NUM>. Preferred features of the invention are set out in the dependent claims. In one aspect, an embodiment of an anti-wobbling adjustable height stool according to the disclosure includes an adjusting screw having a threaded seat support spindle and a top spindle head and a stool seat assembly. The stool seat assembly includes a stool seat, and a connecting frame connected with a bottom of the stool seat. The connecting frame having an installation hole, and the spindle head penetrating through and being arranged in the installation hole to enable a tight fit of the spindle head with the connecting frame.

The anti-wobbling adjustable height stool also includes an underframe assembly having a support, a bushing arranged at a middle of the support and sleeved outside the adjusting screw, the bushing being internally provided with a nut fit with the threaded seat support spindle, and a rubber pad with a fitting recess arranged between the adjusting screw and the bushing. A bottom of the adjusting screw is installed in the fitting recess and in interference fit with the rubber pad, a movable gap ranging from <NUM> to <NUM> being formed between an outer wall of the rubber pad and an inner wall of the bushing.

According to the invention, an anti-wobbling adjustable height stool according to the disclosure includes a threaded seat support spindle; a support; a bushing vertically supported by the support and sleeved outside the threaded seat support spindle, the bushing being internally provided with a nut fit with the threaded seat support spindle, and a pad with a fitting recess arranged between the adjusting screw and the bushing, a bottom of the adjusting screw being installed in the fitting recess and in interference fit with the pad, a movable gap being formed between an outer wall of the pad and an inner wall of the bushing.

In a further aspect, an anti-wobbling stool according to the disclosure includes a support spindle having a cone-shaped top spindle head; and a stool seat assembly. The stool seat assembly includes a stool seat, and a connecting frame connected with a bottom of the stool seat. The connecting frame having a cone-shaped installation hole, and the spindle head penetrating through and being arranged in the cone-shaped installation hole to enable a tight fit of the cone-shaped spindle head with the connecting frame.

Further advantages of the disclosure are apparent by reference to the detailed description when considered in conjunction with the figures, which are not to scale so as to more clearly show the details, wherein like reference numbers indicate like elements throughout the several views, and wherein:.

With reference to the drawings, there is shown an adjustable height stool configured to avoid wobbling and other shortcomings associated with conventional adjustable height stools. The appearance of the stool is also configured to be aesthetically pleasing and includes various ornamental aspects and features.

In the drawing figures, the reference numerals refer to the components of the stool as follows:.

With initial reference to <FIG>, according to an embodiment of the disclosure an anti-wobbling stool structure is provided, which includes an adjusting screw <NUM>, a stool seat assembly and an underframe assembly. The adjusting screw <NUM> includes a threaded seat support spindle <NUM> and a spindle head <NUM> disposed at an upper end of the threaded seat support spindle <NUM>.

The stool seat assembly includes a stool seat <NUM> which is fixedly provided at a bottom thereof with a connecting frame <NUM> having a central installation hole <NUM>. The installation hole <NUM> is desirably tapered to be a cone-shaped hole. The spindle head <NUM> penetrates through and is arranged in the installation hole <NUM>, and the spindle head <NUM> is fittingly engaged with the connecting frame <NUM>. Preferably, the spindle head <NUM> has a smooth outer surface and has a taper matching the taper of the hole <NUM> so as to be cone-shaped in mating relationship with the installation hole <NUM> for facilitating insertion of the spindle head <NUM> into the installation hole <NUM> during installation. A limit boss <NUM> is located at a bottom of the spindle head <NUM> to limit an insertion depth of the adjusting screw <NUM>, thus preventing excessive insertion which might damage the threaded seat support spindle <NUM> and the stool seat <NUM>.

In the depicted embodiment, the connecting frame <NUM> includes a supporting plate <NUM> fixedly connected with the stool seat <NUM> and an installation bushing <NUM> arranged at a bottom of the supporting plate <NUM>. Preferably, a central portion of the support plate <NUM> is configured to define a void area that defines the installation hole <NUM>, with edges of the support plate <NUM> surrounding the installation hole <NUM> curved upwardly to define an installation ring <NUM>. The installation ring <NUM> is configured to fittingly receive an outer surface of the spindle head <NUM>. The installation ring <NUM> is integrally arranged with the supporting plate <NUM> and has a taper consistent with the taper of the spindle head <NUM>.

An inner side wall of the installation bushing <NUM> contacting the spindle head <NUM> has a taper consistent with the taper of the spindle head <NUM>, and the installation bushing <NUM> is in tapered fit with the spindle head <NUM>. When the taper of the installation ring <NUM> is slightly deviated with the taper of the spindle head <NUM> within a tolerance range, the stool seat <NUM> is prevented from loosening. The installation hole <NUM> is arranged to penetrate the supporting plate <NUM> and the installation bushing <NUM>.

During assembly of the stool, the spindle head <NUM> is inserted into the installation hole <NUM>, and the supporting plate <NUM> and the installation bushing <NUM> are tightly connected with the tapered spindle head <NUM> through the tapered installation ring <NUM> and the tapered inner side wall respectively. This is advantageous to provide a large area of contact between the stool seat assembly and the spindle head <NUM> to provide a tight and reliable connection between the stool seat assembly and the adjusting screw <NUM>.

Preferably, the installation bushing <NUM> is set as a solid bushing, which increases the strength of the connection structure and prevents abrasion, looseness or cracking of a connection part between the stool seat <NUM> and the adjusting screw <NUM> after long-term use, thus further ensuring reliable connection. As will be appreciated, the above described structure can be provided to install a seat in a manner to be anti-wobbling even without the height-adjusting aspects of the described embodiment.

In the described embodiment, the underframe assembly includes a support <NUM> shown configured as three support legs which are positioned to contract the ground or floor surface on which the stool is placed. The underframe assembly also includes an elongate cylindrical sleeve or bushing <NUM> located at a middle of the support <NUM> which is sleeved outside the adjusting screw <NUM>. The bushing <NUM> is internally provided with a nut <NUM> fit with the threaded seat support spindle <NUM>, the nut <NUM> is fixedly arranged at a top end inside the bushing <NUM>.

With additional reference to <FIG>, a rubber pad <NUM> is arranged between the adjusting screw <NUM> and the bushing <NUM> and a fitting recess <NUM> is arranged on the rubber pad <NUM>. It will be appreciated that the rubber pad <NUM> may be formed of deformable materials other than rubber to provide the desired padding effect. A bottom of the adjusting screw <NUM> is installed in the fitting recess <NUM> and is in interference fit with the rubber pad <NUM>. A movable gap <NUM> is formed between an outer wall of the rubber pad <NUM> and an inner wall of the bushing <NUM>, and the movable gap <NUM> ranges from <NUM> to <NUM>. It will be appreciated that one end of the adjusting screw <NUM> is fixedly connected with the stool seat <NUM>, the other end of the adjusting screw <NUM> is inserted into the bushing <NUM>, the threaded seat support spindle <NUM> is fit with the nut <NUM> in the bushing <NUM>.

A height of the stool seat <NUM> may be adjusted by rotating the adjusting screw <NUM>. The adjusting screw <NUM> may be limited in a horizontal direction as by the rubber pad <NUM> to prevent the adjusting screw <NUM> and thus the stool seat from wobbling, thereby improving the use experience. Meanwhile, because the adjusting screw <NUM> is installed in the fitting recess <NUM> of the rubber pad <NUM> and is in interference fit with the rubber pad <NUM>, the rubber pad <NUM> may rotate accordingly when the adjusting screw <NUM> is rotated. Therefore, the movable gap <NUM> is arranged between the rubber pad <NUM> and the bushing <NUM> to facilitate the rubber pad <NUM> to rotate and move up and down in the bushing <NUM> along with the adjusting screw <NUM>, and the movable gap <NUM> is controlled to be within a desired range of <NUM> to <NUM>.

Preferably, the movable gap <NUM> is set as <NUM>, with an upper deviation of <NUM> and a lower deviation of -<NUM>, which limits a horizontal movement and prevents a limit effect of the rubber pad <NUM> on the adjusting screw <NUM> from being invalid due to too large gap, or a friction between the rubber pad <NUM> and the bushing <NUM> from being increased due to too small gap, thus being not conducive to rotation adjustment by the adjusting screw <NUM>, thereby ensuring the adjusting screw <NUM> to be easily rotated and.

According to the invention, a washer <NUM> is arranged at a bottom of the rubber pad <NUM>. Preferably, a diameter of the washer <NUM> is smaller than a diameter of the rubber pad <NUM> and not smaller than a diameter of the fitting recess <NUM>. The washer <NUM> and the rubber pad <NUM> are connected by a plurality of bolts <NUM>. Preferably, two bolts <NUM> are arranged. It can be understood that, the rubber pad <NUM> is in interference fit with the adjusting screw <NUM>, when the adjusting screw <NUM> moves up and down, an acting force is exerted to the rubber pad <NUM>, and in particular, when the adjusting screw <NUM> moves downwardly, the bottom of the adjusting screw <NUM> downwardly pushes the rubber pad <NUM>.

Since the adjusting screw <NUM> is installed in the fitting mesa <NUM> of the rubber pad <NUM> and the corresponding rubber pad <NUM> at the fitting recess <NUM> has a smaller thickness, the rubber pad <NUM> is easy to be damaged under the force after long-term use. However, by using the washer <NUM> to support the rubber pad <NUM>, it is prevented that the rubber pad <NUM> may be damaged under the force and thus effectively prolonging a service life of the rubber pad <NUM>. The washer <NUM> is fixedly connected with the rubber pad <NUM> through the bolts <NUM>, thus having a simple structure and convenient installation, and two bolts are used to fix the washer <NUM>, thus preventing the washer <NUM> from rotating to drive the bolts <NUM> to rotate, which leads to that the bolts <NUM> are loosened and fell off, and ensuring reliable connection of the washer <NUM>.

With reference to <FIG>, in the embodiment, the stool seat <NUM> and the supporting plate <NUM> are connected by a plurality of rivets <NUM>. The stool seat <NUM> includes installation recesses <NUM> for accommodating a respective one of the rivets <NUM>, and the supporting plate <NUM> is correspondingly provided with a positioning mesa <NUM> for accommodating the installation recess <NUM>. It can be understood that the stool seat <NUM> and the supporting plate <NUM> are riveted by the rivets <NUM>, thus having a simple structure and reliable connection, and preventing the stool seat <NUM> from loosening and falling off with the supporting plate <NUM>. The rivet <NUM> is installed in the installation recess <NUM> to enable a top end of the rivet <NUM> to be flush with a surface of the stool seat <NUM> to achieve a flat surface of the stool seat <NUM>. The supporting plate <NUM> is correspondingly provided with the positioning mesa <NUM> to be fit with the installation recess <NUM>, the installation recess <NUM> and the positioning mesa <NUM> are in one-to-one correspondence during installation to facilitate installation and positioning, and a position of the stool seat <NUM> is limited in a horizontal direction to prevent the stool seat <NUM> from shifting relative to the supporting plate <NUM>.

Claim 1:
An anti-wobbling adjustable height stool comprising:
an adjusting screw (<NUM>) that includes a threaded seat support spindle (<NUM>) and a spindle head (<NUM>) disposed at an upper end of the threaded seat support spindle (<NUM>);
a support (<NUM>) configured as three support legs which are positioned to contact a ground or floor surface on which the stool is placed;
a bushing (<NUM>) located at a middle of the support (<NUM>), vertically supported by the support (<NUM>) and disposed outside the threaded seat support spindle (<NUM>); the bushing (<NUM>) being internally provided with a nut (<NUM>) fit with the threaded seat support spindle (<NUM>), the nut (<NUM>) being fixedly arranged at a top end inside the bushing (<NUM>);
a rubber pad (<NUM>) arranged between the adjusting screw (<NUM>) and the bushing (<NUM>);
a fitting recess (<NUM>) arranged on the rubber pad (<NUM>);
a washer (<NUM>) arranged at a bottom of the rubber pad (<NUM>), the washer (<NUM>) having a diameter smaller than a diameter of the rubber pad (<NUM>) and not smaller than a diameter of the fitting recess (<NUM>); and
a plurality of bolts (<NUM>) that connect the washer (<NUM>) and the rubber pad (<NUM>),
wherein a bottom of the adjusting screw (<NUM>) is installed in the fitting recess (<NUM>) and is in interference fit with the rubber pad (<NUM>),
wherein a movable gap (<NUM>) is formed between an outer wall of the rubber pad (<NUM>) and an inner wall of the bushing (<NUM>).