Abstract:
An active dynamic seating device is provided that includes a seat, a central part and a base part, where a stable sitting position is attained by additionally supporting one or both legs of a user. The seating device encompasses a tone generator, which emits a tone in response to carrying out a certain change of the sitting position. The seating device is particularly well-suited for, for example, carrying out gymnastics exercises.

Description:
[0001]    This nonprovisional application claims priority under 35 U.S.C. § 119(a) to German Patent Application No. DE 102007025799, which was filed in Germany on Jun. 2, 2007, and which is herein incorporated by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to an active dynamic seating device. 
         [0004]    2. Description of the Background Art 
         [0005]    An active dynamic seating device enables active, dynamic sitting, wherein the back muscles and the spinal disks are always slightly engaged. In virtually all cases, this active dynamic sitting posture is attained in that the actual seat of the seating device swings about at least one lower pivot and is thus held in an unstable position. Additionally, provision can be made for a suspension in the vertical direction. Such sitting devices are formed in particular by rocking stools. 
         [0006]    A rocking stool is known from DE 75 31 129 U1, which corresponds in part to U.S. Pat. No. 4,099,697. However, it is less of a stool than a work seat for working professionals who are obligated to stand while working. Said work seat encompasses a saddle seat, which is adjustable with respect to height and follows each motion of the user. A ball joint disposed above a circular base plate allows the back and forth motion and a tension spring mechanism integrated in the circular base plate effects the automatic return into the neutral position. The height adjustment of the seat and a limited suspension effect are provided by way of a gas spring integrated in the intermediate part. 
         [0007]    A further rocking stool is known as SWOPPER and is described in EP 0 808 116 B1, which corresponds to U.S. Pat. No. 5,921,628, among others. It is a rocking stool that allows height adjustment and comprises a spring column having a suspension that can be adapted to the weight of the user. The deflection of the seat, which is to say the back and forth motion, takes place via a joint between the spring column and the base part. The joint holds the spring column on the base part so as to allow tilting. 
         [0008]    A further rocking stool is known by the name of ERGO. It is a rocking stool that allows height adjustment by means of a gas spring, the back and forth motion of which is attained solely by means of a convex shape of the support surface of a circular base plate. A rocking stool comprising a circular base plate with a convex support surface is also described in DD 73 618 A1. 
         [0009]    The simplest form of a rocking stool only encompasses one seat platform, at the underside of which a central column is fastened in the center, the end of which forms the base part and which is rounded off in a convex manner so as to provide for a tilting or rocking motion. 
         [0010]    All of the cited rocking stools constantly prompt the user to seek and perform balancing motions with respect to the sitting posture. The user of a rocking stool supports himself, on the one hand, with his own two legs and, on the other hand, with the base of the stool on a support or the ground, respectively, only in three points. So as not to topple over, the person sitting down must always balance the center of gravity of his body within the triangular surface, which is defined by these points. A simple one-legged stool, which only comprises the seat platform and a rigid shaft, which protrudes from the seat platform bottom, commands the greatest balancing work from the person sitting down, because the orientation of the stool is not stabilized by any auxiliary means. 
         [0011]    In response to the balancing work on the rocking stool, the lower section of the spine is activated by the initial position of the feet, and all the leg and back muscles are constantly stimulated to carry out fine flexing. This flexing of the muscles, which is physiologically considered to be advantageous, reduces tension when sitting for a long time and thus corrects malpositions and the associated discomfort. A rocking stool is thus also used in physiotherapy in order to strengthen the involved leg and back muscles and boost coordination. For example, a special exercise is to allow the pelvis and thus also the rocking stool to gyrate. Due to the lack of stabilization, such a balancing exercise can meet with unsteadiness in many people so that the exercise fails. 
       SUMMARY OF THE INVENTION 
       [0012]    It is therefore an object of the present invention to provide an active dynamic seating device such that the possible applications thereof for balance exercises are improved. 
         [0013]    An active dynamic seating device comprising a seat, a center part (central column) and a base part is typically formed by a rocking stool of the type any seating device in the broader sense, for example also to an inflatable gymnastics ball-shaped seat made of elastic PVC, which, when inflated firmly, reaches a diameter of approximately 65 cm and forms a resilient seating device, wherein the base part is formed by the support surface of the ball-shaped seat. All active dynamic seating devices have in common that a stable sitting position is attained only by means of the additional support of one or both legs of a user. 
         [0014]    In the embodiment according to the invention, the seating device encompasses a tone generator, which emits a tone in response to carrying out a certain change of the sitting position. With the tone generator, the user of the seating device is given acoustic feedback, which provides him with support when carrying out a gymnastics exercise and can eliminate unsteadiness. Examinations of test persons have shown that an exercise has more success when the attention of the person carrying out the exercise can be focused to an outside intention, that is, an intention, which, has no direct correlation with the execution of the exercise. According to the invention, the intention of the user is focused on the generation of a certain tone. A sound shall also be regarded as a “tone”. What is important is that the tone is perceived by the user and that association is possible. 
         [0015]    An aspect, which is not to be underestimated, is that the game with sound generation appeals to the play instinct of a user and prompts the user to carry out an exercise on the seating device, using concentration and persistence, which he may otherwise consider to be tedious. 
         [0016]    For the support to be able to take place in a specific manner, the tone generator must be configured such that the tone generator is stimulated to emit a certain tone, which is associated with the exercise, only by means of a specific change of the sitting position in the context of an exercise. The user thus attains acoustic feedback as to whether the exercise is being carried out correctly. 
         [0017]    An exercise, which is particularly suitable for strengthening the back muscles, is that the tone generator responds to an exercise, wherein the pelvis of the user cyclically carries out a circular or ellipsoidal motion. 
         [0018]    Generally, electrical or mechanical tone generators are possible. With electrical tone generators, the motion pattern in the seat, center part or base part is sensed by means of acceleration sensors or pressure-sensitive sensors, and acoustic feedback is given after a comparison with stored patterns if the pattern detected by the sensors comes close to a stored exercise pattern. 
         [0019]    A simple mechanical tone generator can be formed in that, by means of a movable mass, which is subject to acceleration caused by a change of the sitting position, a tone is generated in that tone generating elements are stimulated to emit a tone. The tone generating elements can be integrated in the movable mass itself and can be stimulated to emit a tone by the motion of the mass. One example would be a tone ball, which emits a high sphere sound in response to a rolling motion. Such tone balls are known as Qigong balls and are made, e.g., of silver or titanium. 
         [0020]    Alternatively or additionally, the tone generating elements can be arranged along a predetermined track, which the movable mass covers in response to carrying out an exercise and which can be stimulated to emit a tone by means of interaction with the movable mass. One example would be a singing bowl or a ball track, which is stimulated to acoustic oscillations by means of the rolling motion of a ball. 
         [0021]    In one embodiment, the tone generator comprises a ball, the motion of which is guided within a ball track, wherein the ball track is configured such that the ball induces a tone or a sound along the track in response to the rolling motion. For example, the ball track can encompass an inner profile, which emits a sound, note or tone in cooperation with a rolling ball. In the simplest case, a random pattern is already defined for the profile by the material unevenness in the ball track so that, in response to the rolling motion of the ball, a typical sound, such as a swooshing sound, is created, which is similar to the rolling motion of a glass ball on a wood plate. The effect is amplified if the plate and ball track are supported so as to oscillate and can thus serve as a resonator. 
         [0022]    The ball track can be configured such that the user cannot only follow the motion of the ball in the ball track acoustically but also optically, which amplifies the feedback effect. 
         [0023]    One embodiment, in which the ball track is self-contained, has the advantage that the guided ball can carry out an endless motion and can thus stimulate a long lasting tone in response to suitable stimulation by means of the sitting motion. 
         [0024]    One embodiment, in which the self-contained ball track encloses a central axis, which runs through the seat and the base part, has the advantage that the space available at the seat is used optimally and that the weight distribution of the vacant seat can be balanced in a simple manner by a vertical rest position. 
         [0025]    One embodiment, in which the ball track runs within a plane, which intersects the central axis at a right angle, has the advantage that even stimulation of the motion in the ball track takes place in response to a gyrating rocking motion about the vertical rest position of the seating device. Or, in other words: this special arrangement of the ball track supports a gyrating motion about the vertical axis. This is particularly advantageous when used for a seating device, which is formed by a ball-shaped seat, because the ball-shaped seat does not encompass a central axis, which a user can use for reference. 
         [0026]    In an embodiment, the seating device can be formed by a rocking stool, the base part of which is formed by a circular base plate comprising a convex support surface, wherein the ball track is arranged on the base part of the seating device. The ball track can thereby be attached to the base part from the outside, for example, by retrofitting. Alternatively, the ball track is integrated into the base part. This results when the ball track is incorporated in the course of the production process of the base, which overall represents the more cost-efficient solution. 
         [0027]    The tone generator can be equipped as a retrofit kit for the intended use in an active dynamic seating device. This has the advantage that already available active dynamic seating devices can be used and equipped with the advantages according to the invention. For a rocking stool, the retrofitting could include a ball track comprising a ball, which is retroactively attached to the base part of the rocking stool. For a ball-shaped seat as seating device, a tube, which is closed to form an annulus, would be possible as a ball track, for example, which is placed over the ball-shaped seat and held in a meridian position by means of a press fit. A ball revolving in the tube would be put into a revolving motion by a gyrating motion of the pelvis of a user and would generate a corresponding sound in response to a rolling motion. 
         [0028]    Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0029]    The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein: 
           [0030]      FIG. 1  shows a longitudinal section through an active dynamic seating device according to the invention; 
           [0031]      FIG. 2  shows a top view onto the base par of the seating device; 
           [0032]      FIG. 3   a  shows a top view onto the base part of the seating device comprising a two-sided delimiter  9   a ; and 
           [0033]      FIG. 3   b  shows a top view onto the base part of the seating device comprising two one-sided delimiters  9   b ,  9   c.    
       
    
    
     DETAILED DESCRIPTION 
       [0034]      FIG. 1  shows a rocking stool as seating device  1 . The rocking stool comprises a base part  2 , which centrally accommodates a central column  3 , on which a seat  4  is fastened. The base part  2  is formed by a circular base plate  2   a  having a diameter of 400 mm and a convex support surface  2   b , wherein the radius of curvature of the support surface is 725 mm. In the known manner, the central column  3  comprises a gas spring for height adjustment, as it is known for office chairs, which allows height adjustment of the seat in the range of 540-740 mm. The height adjustment can be brought about manually by means of a trigger  6 . The seat is cushioned slightly, wherein the seat cover encompasses only small to medium grip in order to facilitate gymnastics exercises. 
         [0035]    The tone generator  7   a ,  7   b , which comprises a ball  7   a , which can revolve in a circle in a ball track  7   b , is arranged in the base part. The ball  7   a  can have a diameter of 10-30 mm. The ball track  7   b  is adapted to the diameter of the ball  7   a  and forms a circle having a diameter of 320 mm. The wall of the ball track  7   b , which is located in a radially external direction, serves the purpose of guiding the ball at a high circumferential velocity with a high centrifugal force. The rolling motion of the ball along said circle generates a characteristic sound, which provides feedback to the user that he is carrying out the exercise correctly. 
         [0036]    The circle radius of the interior wall of the ball track  7   b  must leave sufficient play for the course of the ball  7   a . A reduction of the radius of the inside wall allows for more play for the ball  7   a . The radius can be reduced to the extent that the inner wall abuts the central column  3 . In this case, the ball track transitions into a ball cup. 
         [0037]    So as to be able to safely guide the ball even in response to an intense motion, the ball track can be undercut so that the ball cannot leave the ball track. 
         [0038]    In the exemplary embodiment, the base part  2  encompasses a cover  8 , which has a thickness of approx. 6 mm, which serves the purpose of stabilizing the base part  2  and designing the tone generation in that the ball  7   a  hitting the inner wall produces a different sound than when hitting the outer wall. The cover makes it possible to implement different surfaces according to color and feel. If the base is configured as a hollow body or as a plate structure body, the inner structure can be covered by means of the cover. The cover could at least partially cover the ball track in order to prevent the ball from escaping. As a deep drawn component made of plastic or metal in one piece, the cover could also accommodate the ball track. The cover comprising the integrated ball track could be offered for sale as a tone generator for retrofitting an existing rocking stool. 
         [0039]    The base part  2  comprising the ball track  7   a  is preferably made in one piece, for example by means of milling out a hard foam component or by the production thereof by means of a casting process in a shape, which represents the ball track. 
         [0040]    It goes without saying that the concrete height dimensions only represent approximate information, which can be deviated from if there is a need, considering the dimensions and adaptation to given factors. 
         [0041]      FIG. 2  shows a top view onto the base part  2  comprising the cross-sectional surface of the central column  3 . The circular ball track  7   b  for the ball  7   a  is defined by the radially outer wall  7   c  and by the radially inner wall  7   d . As already described, the inner wall  7   d  can extend up to the column  3 . 
         [0042]    By suitably selecting the radius of the ball track  7   b  and the mass of the ball  7   a , minimum activity can be systematically predetermined for the gyrating motion of the pelvis of a user. The ball  7   a  will revolve around the central column  3  in a circular path only if the user has adjusted the speed and rocking stroke of the exercise such that he exceeds said minimum activity, which provides him with the desired feedback. 
         [0043]    As is shown in  FIG. 3   a  and  FIG. 3   b , the delimiters  9   a ,  9   b ,  9   c , which can be inserted into the ball track  7   b  and which block the path of the ball  7   a , provide for an enhancement of the application possibilities. The delimiters are fixed in a permanent position within the ball track  7   b , for example by means of clamping. Upon striking the ball  7   a , the delimiters emit a characteristic tone. The tone results either from the material, such as the wood or metal of the delimiters, or from striking the outer contact surfaces, which are provided with delimiter tone generators  10  of their own. A delimiter tone generator made of metal or wood, for example, thus emits a characteristic tone, which can be associated by the user. A one-sided delimiter  9   b ,  9   c  encompasses only a single delimiter tone generator  10 , wherein a differentiation can be made between left-sided and right-sided delimiter. A two-sided delimiter  9   a  encompasses, on the opposite contact surfaces, a delimiter tone generator  10  in each case. 
         [0044]    If a delimiter  9   a , as is shown in  FIG. 3   a , were disposed in a rear direction in the ball track  7   b  from the user&#39;s perspective, the ball would not follow a revolving, closed track, but would be reflected at the delimiter  9   a . The tone generated when the ball  7   a  strikes the delimiter  9   a  provides characteristic feedback to the user, which supports him in his exercise. Due to the symmetric division of the track imposed on the ball  7   a , the use of a two-sided delimiter  9   a  is advisable here, because the ball can strike both contact surfaces located opposite to one another. 
         [0045]    However, it is also possible to limit the path of the ball to a track section between two one-sided delimiters  9   b ,  9   c , as is shown in  FIG. 3   b . If two delimiters  9   b ,  9   c  were laterally inserted into the ball track  7   b  on the left-hand side and the right-hand side from the user&#39;s perspective, the motion of the ball  7   a  could be forced onto the track section between the delimiters. Only an exercise with distinct lateral hip motions would accelerate the ball such that it would alternately strike the left and right delimiters  9   b ,  9   c , which provide concrete feedback to the user relating to the intensity of the exercise, which is carried out. 
         [0046]    A delimiter  9   a ,  9   b ,  9   c  can be formed in a simple manner in that a metal core is used, which has a smaller diameter than the width of the ball track  7   b , which results from the radius difference between the radially outer wall  7   c  and the radially inner wall  7   d . Said metal core is encased by an elastic hose, for example made of foamed rubber. The hose is dimensioned such that the encased metal core can be clamped into the ball track  7   b  only by applying force, thus fixing the delimiter  9   a ,  9   b ,  9   c  into the position thereof by means of a press fit and thus not being moved by a striking of the ball. A wood core can also be used instead of a metal core. 
         [0047]    A delimiter could also be completely made of metal and could be locked in the ball track by means of clamping jaws. The clamping jaws could be forced apart by means of a screw located internally, which can be tightened, for example, by means of an Allen wrench. 
         [0048]    The cover  8  is once again illustrated in  FIG. 3   b  and can be embodied as a replacement part, in that the geometry thereof is adapted to the base part  2 . The replacement of the cover  8  is performed in that the seat  4  is removed and the central column is guided through the central hole of the cover  8 . In the alternative, the cover can encompass a radially extending slot  10  and can be guided around the central column like a paper ring for covering a base of a goblet, by means of slightly expanding the radial edges of the cover on the slot  10 . The cover is then fixed on the base part  2  so as to be invisible from the outside, for example by means of a double-sided adhesive strip or clips and a clamping strip. 
         [0049]    On the visible side thereof, the cover  8  can be imprinted with color. If the cover  8  serves rather the display of information than the design-related material reinforcement, the wall thickness thereof can be configured to be thinner than the specified 6 mm. The above-described delimiters could also be fastened to the cover so that the delimiters would be moved into their positions by attaching the cover  8 . Different covers could thus be provided for different delimiter arrangements. 
         [0050]    The described concept of a replaceable cover, which can be offered in a wide variety of embodiments as a replacement part, is not limited to being used for the present rocking stool, but can also be used for other rocking stools comprising a central column, as are known from the state of the art, and represents an independent inventive idea. 
         [0051]    In one embodiment, the base part  2  can be shaped from solid wood by means of milling or turning, wherein the ball track  7   b  was also produced by means of milling or turning. This embodiment produces a pleasant tone in response to a rolling motion of a ball in the ball track. 
         [0052]    The above embodiment has been described in an example where the tone generator comprises a ball, the motion of which is guided within a ball track. However, any kind of movable mass, which is subject to acceleration by changing the sitting position, can be used instead of a ball. For example, a small toy car with wheels can be used instead of a ball. 
         [0053]    The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims.