Patent Publication Number: US-7708340-B2

Title: Massage chair

Description:
TECHNICAL FIELD 
     The invention relates generally to massage chairs and more particularly to a massage chair that uses reclining movement of a backrest for stretching user&#39;s arms. 
     BACKGROUND ART 
     Such a massage machine is described in, for example, Japanese Patent Application Publication No. 2005-152260 issued Jun. 16, 2005. This machine (hereinafter referred to as a “first prior art”) uses an electric reclining mechanism of a backrest to obtain a stretch (extension) effect on the user&#39;s arms and shoulders. That is, the first prior art swells upper and lower airbags located at each of left and right armrests to hold each hand and forearm of the user with each upper and lower airbags, and moves the backrest into an end position from a start position to lean the upper part of the user&#39;s body backward. The start position is a sloping position, and the end position is a sloping position that has an inclination larger than the start position with respect to the vertical direction. In case of a first operational example, the first prior art moves the backrest into the end position while swelling the airbags of the armrests; returns the backrest to the start position after the airbags finish swelling; and shrinks the airbags after holding each swell condition of the airbags for a specified time. In case of a second operational example, the first prior art swells the airbags of the armrests; moves the backrest into the end position after the airbags finish swelling; and returns the backrest to the start position while shrinking the airbags after holding each swell condition of the airbags for a specified time. However, in this first prior art, there is an issue that the two sets of upper and lower airbags restrain the user&#39;s arms simultaneously. 
     Another massage machine described in Japanese Patent Application Publication No. 2005-177278 issued Jul. 7, 2005 can solve the issue. This massage machine (hereinafter referred to as a “second prior art”) also swells upper and lower airbags located at each of left and right armrests to hold each hand and forearm of the user with each upper and lower airbags, and moves the backrest into an end position from a start position to lean the upper part of the user&#39;s body backward. At this point, the second prior art adjusts holding strength by upper and lower airbags located at one of the left and right armrests so that the user can take the corresponding arm off the upper and lower airbags. Therefore, the second prior art can prevent two sets of upper and lower airbags from restraining the user&#39;s arms simultaneously. 
     However, the second prior art decreases holding strength by upper and lower airbags located at one of the left and right armrests and accordingly cannot hold the user&#39;s corresponding hand and forearm surely. 
     DISCLOSURE OF THE INVENTION 
     It is an object of the present invention to use reclining movement of a backrest for stretching the user&#39;s arms not to restrain the arms simultaneously, without adjusting holding strength by one of left and right holding mechanisms so that the user can take the corresponding arm off the one of left and right holding mechanisms. 
     A massage chair of the present invention comprises a base, a reclining backrest, an electric reclining mechanism, a left holding mechanism, a right holding mechanism and a controller. The base includes a seat. The reclining backrest is located at the back of the base. The electric reclining mechanism is configured to move the backrest into different sloping positions. The left holding mechanism is configured to hold at least left forearm of a user to fix the at least left forearm to the base side. The right holding mechanism is configured to hold at least right forearm of the user to fix the at least right forearm to the base side. The controller is configured to control operations of the electric reclining mechanism and the left and right holding mechanisms. According to an aspect of the invention, the controller separately controls operations of the electric reclining mechanism and the left holding mechanism as well as operations of the electric reclining mechanism and the right holding mechanism. When controlling operations of the electric reclining mechanism and the left holding mechanism, the controller controls (A) allow the left holding mechanism to hold the at least left forearm, (B) allow the electric reclining mechanism to recline the backrest to any of the different sloping positions, (C) allow the electric reclining mechanism to raise the backrest to any of the different sloping positions, and (D) allow the left holding mechanism to release the at least left forearm. When controlling operations of the electric reclining mechanism and the right holding mechanism, the controller controls (a) allow the right holding mechanism to hold the at least right forearm, (b) allow the electric reclining mechanism to recline the backrest to any of the different sloping positions, (c) allow the electric reclining mechanism to raise the backrest to any of the different sloping positions, and (d) allow the right holding mechanism to release the at least right forearm. 
     In this invention, one side of the user&#39;s arms and shoulder is stretched and then released, and afterwards the other side is stretched and then released. Accordingly, it is possible to use reclining movement of the backrest for stretching the user&#39;s arms and shoulders not to restrain the arms simultaneously, without adjusting holding strength by one of the left and right holding mechanisms so that the user can take the corresponding arm off the one of left and right holding mechanisms. 
     In a preferred embodiment, the massage chair further comprises left and right armrests. The left holding mechanism comprises: a left cover that is located above the left armrest and covers the at least left forearm; at least one first airbag located at the left armrest and/or the left cover; and an air supply pump for swelling the first airbag. The right holding mechanism comprises: a right cover that is located above the right armrest and covers the at least right forearm; at least one second airbag located at the right armrest and/or the right cover; and said or another air supply pump for swelling the second airbag. When holding the at least left forearm, the controller controls to swell the first airbag through the air supply pump of the left holding mechanism to hold the at least left forearm with the first airbag, the left armrest and the left cover. When holding the at least right forearm, the controller controls to swell the second airbag through the air supply pump of the right holding mechanism to hold the at least right forearm with the second airbag, the right armrest and the right cover. In this construction, it is possible to hold the at least left and right forearms elastically with the first and second airbags, respectively. Moreover, this invention can prevent the left and right holding mechanisms from putting stress on the user&#39;s left and right forearms in a stretching operation of the at least left and right forearms, respectively. 
     Preferably, in case that a sloping position of the backrest has an inclination larger than a reference sloping position of the different sloping positions with respect to the vertical direction, the controller controls to allow the electric reclining mechanism to raise the backrest to the reference sloping position before allowing any of the left and right holding mechanisms to hold the corresponding at least forearm of the user. This invention can stretch the user&#39;s arms and shoulders with sufficient strength. 
     In another preferred embodiment, the controller controls to increase holding force by the first airbag as allowing the electric reclining mechanism to recline the backrest after holding the at least left forearm with the first airbag, the left armrest and the left cover. The controller also controls to increase holding force by the second airbag as allowing the electric reclining mechanism to recline the backrest after holding the at least right forearm with the second airbag, the right armrest and the right cover. In this construction, the at least left and right forearms can be held properly with the first and second airbags, respectively, without applying excessive force during a stretching operation each of them. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Preferred embodiments of the invention will now be described in further details. Other features and advantages of the present invention will become better understood with regard to the following detailed description and accompanying drawings where: 
         FIG. 1  is a schematic diagram of an embodiment according to the present invention seen from the right side; 
         FIG. 2  is a schematic diagram of the embodiment seen from the front side; 
         FIG. 3  is an explanatory diagram of a left holding mechanism in the embodiment; 
         FIG. 4  is a block diagram of a drive system in the embodiment; 
         FIG. 5  is an explanatory diagram of a keypad in the embodiment; 
         FIG. 6  is a time chart of a stretching operation of the embodiment; 
         FIGS. 7A and 7B  are explanatory diagrams of an issue to be solved in the embodiment; 
         FIG. 8  is explanatory diagrams of an advantage of the embodiment; 
         FIGS. 9A and 9B  are explanatory diagrams of an advantage of the embodiment; 
         FIG. 10  is a time chart of a stretching operation of a preferred embodiment; 
         FIG. 11  is an explanatory diagram of the stretching operation; and 
         FIGS. 12A and 12B  are explanatory diagrams of a preliminary operation in the preferred embodiment. 
     
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
       FIGS. 1 and 2  show an embodiment according to the present invention, namely a massage chair  1 . For example, this chair  1  comprises a base  10 , a leg/foot rest  12 , a reclining backrest  13 , a massage mechanism  14 , an electric reclining mechanism  15 , left and right armrests  16  and  17 , left and right holding mechanisms  18  and  19 , and a drive system  100  (see  FIG. 4 ). The base  10  includes a seat  11 . The leg/foot rest  12  is configured so as to be supported by at least one axis fixed to the base  10  to rise and fall by rotating about the axis through an electric elevating mechanism (not shown) put in the base  10 . This mechanism is well known to those skilled in the art and therefore is not described in detail herein. 
     The backrest  13  is located at the back of the base  10  and can be reclined to different sloping positions such as sitting position, full reclining position and so on through the electric reclining mechanism  15  constructed of a motor  151  and a link mechanism  152  in the same way as conventional massage chairs. In this embodiment, the backrest  13  can be reclined to any of eight sloping positions equally divided in the reclining direction. The massage mechanism  14  is an elevating massage mechanism located in the backrest  13 , and has left and right massage heads (e.g., kneading balls)  141  and  142  that simulate massage movement (e.g., kneading and tapping) to give a user a massage in accordance with control of the drive system  100 . In general, the massage mechanism  14  is driven after the backrest  13  is moved into a desired sloping position through a sloping-position adjusting key (not shown). 
     As shown in  FIGS. 1-4 , the left and right armrests  16  and  17  are installed at the left and right sides of the base  10  and are provided with the left and right holding mechanisms  18  and  19 , respectively. The left holding mechanism  18  includes a left cover  181 , upper and lower airbags (first airbags)  182  and  183 , electronic valves  184  and  185 , and an air supply pump  186 . The cover  181  is formed so as to cover at least left forearm of a user. In this embodiment, the cover  181  is formed to cover the user&#39;s left hand and forearm, and is supported by an axis fixed to the front of the left armrest  16  to move upward and downward in the upside of the armrest  16  by rotating about the axis. In addition, for example, by an electric mechanism (not shown), the cover  181  can be moved into a predetermined angle in a specified range and then be locked. The airbag  182  is installed on the bottom face of the cover  181  and is coupled to the pump  186  or the atmosphere through the electronic valve  184 , while the airbag  183  is installed on the top face of the armrest  16  and is coupled to the pump  186  or the atmosphere through the electronic valve  185 . The electronic valve  184  is driven by the drive system  100  to couple the airbag  182  to the pump  186  and the atmosphere in case of air supply and exhaust, respectively. The electronic valve  185  is also driven by the drive system  100  to couple the airbag  183  to the pump  186  and the atmosphere in case of air supply and exhaust, respectively. The pump  186  is driven by the drive system  100 . 
     Similarly, the right holding mechanism  19  includes a right cover  191 , upper and lower airbags (second airbags)  192  and  193 , electronic valves  194  and  195 , and the air supply pump  186 . However, not limited to this, the right holding mechanism  19  may comprise another air supply pump instead of the pump  186 . Each airbag of the left and right holding mechanisms  18  and  19  is formed from flexible materials and has airtightness. The cover  191  is formed so as to cover at least right forearm of a user. In the embodiment, the cover  191  is formed to cover the user&#39;s right hand and forearm, and is supported by an axis  171  fixed to the front of the right armrest  17  to move upward and downward in the upside of the armrest  17  by rotating about the axis  171 . In addition, for example, by an electric mechanism (not shown), the cover  191  can be moved into a predetermined angle in a specified range and then be locked. However, not limited to these, the covers  181  and  191  may be fixed to the left and right armrests  16  and  17  at a predetermined angle, respectively. The airbag  192  is installed on the bottom face of the cover  191  and is coupled to the pump  186  or the atmosphere through the electronic valve  194 , while the airbag  193  is installed on the top face of the armrest  17  and is coupled to the pump  186  or the atmosphere through the electronic valve  195 . The electronic valve  194  is driven by the drive system  100  to couple the airbag  192  to the pump  186  and the atmosphere in case of air supply and exhaust, respectively. The electronic valve  195  is also driven by the drive system  100  to couple the airbag  193  to the pump  186  and the atmosphere in case of air supply and exhaust, respectively. 
     The drive system  100  comprises a keypad  101  as an input means, an angle sensor  102 , a controller  103  and so on. As shown in  FIG. 5 , the keypad  101  comprises various keys such as a power on/off key  101   a , an arm/shoulder stretch key  101   b  and so on in addition to the above sloping-position adjusting key. The angle sensor  102  is configured to detect the angle of a sloping position of the backrest  13 . The controller  103  is, for example, constructed of one or more microcomputers, a storage device and so on, and has various programs, data on angles of the different sloping positions and so on. This controller  103  controls operations of different mechanisms based on different instructions obtained from the keypad  101 , detection result of the angle sensor  102  and so on. The different mechanisms include the electric elevating mechanism of the leg/foot rest  12 , the elevating massage mechanism, the electric reclining mechanism  15 , the left and right holding mechanisms  18  and  19  and so on. 
     In addition to various controls executed in the same way as conventional massage chairs, the controller  103  provides the control for stretching the user&#39;s arms and shoulders according to an aspect of the embodiment when the key  101   b  is pressed after switch-on by pressing the key  101   a . That is, the controller  103  controls to move the covers  181  and  191  into the predetermined angle to lock the covers  181  and  191  through the electric mechanisms of the left and right holding mechanisms  18  and  19 , respectively. Afterwards, the controller  103  provides the control for stretching the user&#39;s left arm and shoulder and the control for stretching the right arm and shoulder separately (e.g., alternately). The both controls constitute a stretching operation of the arms and shoulders. 
     Expanding on this stretching operation, for example, the controller  103  controls to swell the airbags  182  and  183  through the electronic valves  184  and  185  and the pump  186  to hold the left hand and forearm elastically with the airbags  182  and  183 . That is, the controller  103  controls to allow the left holding mechanism  18  to hold the left hand and forearm. The controller  103  then controls to allow the electric reclining mechanism  15  to recline the backrest  13  from a start position to an end position based on detection result of the angle sensor  102 . At this point, the controller  103  dives the motor  151  so that the detection result agrees with the angle of an objective sloping position stored in the storage device of the controller  103 . The start and end positions are included in the above different sloping positions, and the end position has an inclination larger than the start position with respect to the vertical direction. The controller  103  also controls to increase holding force by the first airbags as allowing the electric reclining mechanism  15  to move the backrest  13  from the start position to the end position. The controller  103  then controls to allow the electric reclining mechanism  15  to raise the backrest  13  from the end position to a return position based on detection result of the angle sensor  102 . The return position is included in the different sloping positions, and has an inclination smaller than the end position with respect to the vertical direction. In the embodiment, the return position is same as the start position. The controller  103  controls to shrink the airbags  182  and  183  through the electronic valves  184  and  185  and the pump  186  to release the left hand and forearm. That is, the controller  103  controls to allow the left holding mechanism  18  to release the left hand and forearm. 
     Similarly, the controller  103  controls to allow the right holding mechanism  19  to hold the right hand and forearm. The controller  103  then controls to allow the electric reclining mechanism  15  to move the backrest  13  from a start position to an end position and afterwards from the end position to a return position based on detection result of the angle sensor  102 . The controller  103  also controls to increase holding force by the second airbags as allowing the electric reclining mechanism  15  to move the backrest  13  from the start position to the end position. The controller  103  then controls to allow the right holding mechanism  19  to release the right hand and forearm. 
     The controller  103  also utilizes the airbags  182 ,  183 ,  192  and  193  as massage means. In this case, the controller  103  swells and shrinks at least one of the airbags  182 ,  183 ,  192  and  193  while driving the pump  186 . 
     The operation of the massage chair  1  is now explained with reference to  FIG. 6 , as follows. When the key  101   b  is pressed after switch-on by pressing the key  101   a , the controller  103  moves the covers  181  and  191  into the predetermined angle to lock the covers  181  and  191  through the electric mechanisms of the left and right holding mechanisms  18  and  19 , and then starts and repeats the stretching operation. 
     In each stretching operation, first, the controller  103  provides the control for stretching the user&#39;s left arm and shoulder or the control for stretching the right arm and shoulder. For example, the controller  103  swells the airbags  182  and  183  through the electronic valves  184  and  185  and the pump  186 . At this point, the controller  103  drives the electronic valves  184  and  185  to couple the airbags  182  and  183  to the pump  186 , and also drives the pump  186 . After a waiting time T 1 , the controller  103  moves the backrest  13  into an end position from a start position at a constant speed through the electric reclining mechanism  15 . The time T 1  is set to a time necessary to hold one hand and forearm surely with the corresponding airbags. After few seconds from a point in time at which the backrest  13  reaches the end position, the controller  103  shrinks the airbags  182  and  183  through the electronic valves  184  and  185  and the pump  186 . At this point, the controller  103  drives the electronic valves  184  and  185  to couple the airbags  182  and  183  to the atmosphere, and also stops the pump  186 . The controller  103  also starts moving the backrest  13  into a return position from the end position at a constant speed through the electric reclining mechanism  15 . 
     After (or immediately after) the backrest  13  reaches the return position, the controller  103  swells the airbags  192  and  193  through the electronic valves  194  and  195  and the pump  186 . At this point, the controller  103  drives the electronic valves  194  and  195  to couple the airbags  192  and  193  to the pump  186 , and also drives the pump  186 . After a waiting time T 1 , the controller  103  moves the backrest  13  into an end position from a start position at a constant speed through the electric reclining mechanism  15 . After few seconds from a point in time at which the backrest  13  reaches the end position, the controller  103  shrinks the airbags  192  and  193  through the electronic valves  194  and  195  and the pump  186 . At this point, the controller  103  drives the electronic valves  194  and  195  to couple the airbags  192  and  193  to the atmosphere, and also stops the pump  186 . The controller  103  also starts moving the backrest  13  into a return position from the end position at a constant speed through the electric reclining mechanism  15 . When the backrest  13  reaches the return position, one stretching operation of the user&#39;s arms and shoulders is completed. However, not limited to this stretching operation, the controller of the present invention may control to stretch the user&#39;s left (or right) arm and shoulder once or more, and then stretch the right (or left) arm and shoulder once or more. 
     In this embodiment, one side of the user&#39;s arms and shoulders is stretched and then released, and afterwards the other side is stretched and then released. Accordingly, it is possible to use reclining movement of a backrest for stretching the user&#39;s arms not to restrain the arms simultaneously, without adjusting holding strength by one of left and right holding mechanisms so that the user can take the corresponding arm off the one of left and right holding mechanisms. In addition, since one of the user&#39;s arms is always free, the user can operate the keypad  101  during a stretching operation. Also, since the backrest  13  is kept at an end position for few seconds, a preferable stretch effect can be obtained. Moreover, after holding one hand and forearm of the user surely with the corresponding airbags, the controller  103  controls to increase holding force by the corresponding airbags as allowing the electric reclining mechanism  15  to move the backrest  13  into an end position from a start position. Accordingly, the left and right hands and forearms can be held properly with the first and second airbags, respectively, without applying excessive force during a stretching operation. 
     Expanding on other advantages of this embodiment, the massage chair  1  can be prevented from pulling the user&#39;s arms strongly in a stretching operation. In case that the user&#39;s arms are comparatively long as shown in  FIG. 7A , the first or second prior art can always support the upper part of the body by its backrest  13 PA in a stretching operation of the arms. However, in case that the user&#39;s arms are comparatively short as shown in  FIG. 7B , the backrest  13 PA cannot always support the upper part of the body in a stretching operation. As a result, since the upper part of the body is completely apart from the backrest  13 PA, the arms are pulled strongly. In this embodiment, even if the user&#39;s arms are comparatively short as shown in an example of  FIG. 8 , one side (e.g., right side) of the upper part of the body is supported by the backrest  13  when the opposite arm (e.g., left arm) is stretched, and accordingly the massage chair  1  can be prevented from pulling the user&#39;s arms strongly. 
     In addition, the left and right holding mechanisms  18  and  19  can be prevented from putting stress on the user&#39;s left and right forearms in a stretching operation, respectively. For example, a massage machine described in Japanese Patent Application Publication No. 2005-013463 issued Jan. 20, 2005 comprises left and right holding mechanisms located at left and right armrests, respectively. As shown in  FIG. 9A , each of the holding mechanisms comprises a U-shaped supporter  181 PA (or  191 PA), and left and right airbags  182 PA and  183 PA (or  192 PA and  193 PA) installed inside the supporter. In such holding mechanisms, when the user&#39;s arms are stretched simultaneously, the supporters  181 PA and  191 PA interfere with movement of the user&#39;s left and right forearms to put stress on the left and right forearms, respectively. In the embodiment, the upper and lower airbags  182  and  183  are respectively installed at the cover  181  and the armrest  16  as shown in  FIG. 9B . The upper and lower airbags  192  and  193  are also installed at the cover  191  and the armrest  17 , respectively. Accordingly, since the covers  181  and  191  do not interfere with movement of the user&#39;s left and right forearms, the holding mechanisms  18  and  19  can be prevented from putting stress on the left and right forearms. 
     In a modified embodiment, the controller  103  is configured to swell one of the airbags  182  and  183  when holding the user&#39;s left hand and forearm, and also swell one of the airbags  192  and  193  when holding the right hand and forearm. However, not limited to this, the left mechanism  18  may be provided with an upper or lower airbag and a lower or upper cushion instead of the airbags  182  and  183 , and also the right mechanism  19  may be provided with an upper or lower airbag and a lower or upper cushion instead of the airbags  192  and  193 . In short, the left holding mechanism of the present invention may comprise: a left cover that is located above the left armrest  16  and covers at least the left forearm of a user; at least one first airbag located at the left armrest and/or the left cover; and an air supply pump for swelling the first airbag. Similarly, the right holding mechanism of the present invention may comprise: a right cover that is located above the right armrest  17  and covers at least the right forearm of the user; at least one second airbag located at the right armrest and/or the right cover; and said or another air supply pump for swelling the second airbag. 
     In a preferred embodiment, when a sloping position of the backrest  13  has an inclination larger than a reference sloping position of the above different sloping positions with respect to the vertical direction, the controller  103  controls to allow the electric reclining mechanism  15  to raise the backrest  13  to the reference sloping position before allowing any of the left and right holding mechanisms  18  and  19  to hold the corresponding at least forearm of the user. The operation of this control is hereinafter referred to as a “preliminary operation” (see  FIG. 10 ). The different sloping positions are eight sloping positions equally divided in the reclining direction as shown in an example of  FIG. 11 , and the reference sloping position is, for example, the second sloping position  2  from the vertical direction and has an inclination α. The stretch strength on the user&#39;s left arm depends on the position of the left hand put on the armrest  16 , and the stretch strength on the right arm also depends on the position of the right hand put on the armrest  17 . For example, as shown in  FIG. 12A , in case that the user&#39;s left and right hands are deeply inserted into the left and right holding mechanisms  18  and  19 , the stretch strength on the arms is increased. As shown in  FIG. 12B , in case that the left and right hands are slightly inserted into the holding mechanisms  18  and  19 , the stretch strength on the arms is decreased. In this preferred embodiment, when a sloping position of the backrest  13  has an inclination larger than the reference sloping position, the controller  103  provides the control for the preliminary operation so that the user&#39;s left and right hands are deeply inserted into the left and right holding mechanisms  18  and  19 , respectively. Preferably, the inclination α is set to, for example, 30° or less, and is stored in the storage device of the controller  103 . 
     The operation of this preferred embodiment is now explained. In each stretching operation, when a sloping position of the backrest  13  has an inclination larger than the reference sloping position, the controller  103  performs the control for the preliminary operation based on detection result of the angle sensor  102  as shown in  FIG. 10 . At this point, the controller  103  drives the electric reclining mechanism  15  so that detection result of the angle sensor  102  agrees with the angle of the reference sloping position. Afterwards, the controller  103  provides the control for stretching the user&#39;s left arm and shoulder or the control for stretching the right arm and shoulder. This preferred embodiment can stretch the user&#39;s arms and shoulders with sufficient strength. 
     In another modified embodiment, the controller  103  is configured to stop the pump  186  immediately after the backrest  13  reaches an end position and, after few seconds, drive the corresponding electronic valves to couple the corresponding airbags to the atmosphere. In this construction, immediately after the backrest  13  reaches an end position, increase of holding force by the corresponding airbags can be stopped, and holding force when the backrest  13  reaches the end position can be kept for few seconds. 
     Although the present invention has been described with reference to certain preferred embodiments, numerous modifications and variations can be made by those skilled in the art without departing from the true spirit and scope of this invention.