Abstract:
A wheelchair includes a seat, one or more wheels and a seat weight sensing mechanism. The wheel includes a brake for stopping the wheel. The seat weight sensing mechanism is placed below the seat and is connected to the brake. When the seat is loaded by a weight more than a predetermined value, the seat weight sensing mechanism releases the brake to free the wheel. When the seat is not loaded by a weight more than a predetermined value, the brake stops the wheel.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Under 35 USC 120, this application is a divisional application of U.S. application Ser. No. 12/399,459, filed Mar. 6, 2009, all of which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     (A) Field of the Invention 
     The present invention is related to a wheelchair, a wheelchair apparatus and a wheelchair care service network system, and more specifically, to a wheelchair, a wheelchair apparatus and a wheelchair care service network system having automatic brake and user posture detection functions. 
     (B) Description of the Related Art 
     Wheelchairs are indispensable items for disabled people, and most wheelchairs feature only basic functions and are propelled manually. Manual wheelchairs can be propelled carelessly or accidentally, and therefore are not stable and safe apparatuses. Many disabled people cannot operate or control their wheelchairs with sufficient caution, and as a result accidents frequently occur. 
     In clinical use, accidents occur most frequently when the user stands up or sits down. The wheelchair may suddenly slip, causing the user to trip. In addition, other accidents frequently occur when the user stands behind the wheelchair and pushes the wheelchair to move forward. The user may walk unsteadily and fall if the wheelchair slips abruptly. In addition to user falls, other problems can occur, including bedsores due to local compression or body deformation due to incorrect posture, both of which are common symptoms suffered by those who sit in their wheelchairs for a long time. 
     In current clinical settings, prevention of such mishaps and ailments caused by wheelchairs is maintained as part of the overall health care management system. However, with the aging of the population and increasing health care costs, more care providers must take care of many patients. As a result, less attention is given to each patient. Therefore, there is a need to reduce the tasks of the health care worker by use of technology to perform tasks such as monitoring of body postures and physiology states or the predictions of high risk conditions. Such tasks can be handled by a well prepared detection system. The system can warn the wheelchair users and care providers. 
     SUMMARY OF THE INVENTION 
     The present invention provides a wheelchair having an automatic brake, a wheelchair apparatus of user posture detection function and a wheelchair care service network system, which can be applied to clinics or families. 
     In accordance with an embodiment of the present invention, a wheelchair includes a seat, at least one wheel and a seat weight sensing mechanism. The wheel includes a brake to stop the wheel. The seat weight sensing mechanism is disposed below the seat and is connected to the brake. The seat weight sensing mechanism releases the brake to unlock the wheel when the seat is loaded over a predetermined weight, and the brake stops the wheel when the seat is not loaded over a predetermined weight. 
     In accordance with an embodiment of the present invention, a wheelchair apparatus includes a wheelchair and a data processing unit. The wheelchair includes a seat, a seat back and an armrest, and at least one of the seat, the seat back and the armrest is provided with a plurality of sensors. The data processing unit is configured to process data obtained by the sensors to analyze a user&#39;s posture and action. 
     In accordance with an embodiment of the present invention, a wheelchair care service network system includes a wheelchair, a server and at least one user interface. The wheelchair includes a seat, a seat back and an armrest, in which at least one of the seat, the seat back and the armrest is provided with a plurality of sensors. The wheelchair further includes a data processing unit for processing data obtained by the sensors to analyze a user&#39;s posture or action. The server is configured to store and process the sensed data from the wheelchair. The user interface is connected to the server and allows a care provider to access the data in the server. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1 to 4  show a wheelchair in accordance with an embodiment of the present invention; 
         FIGS. 5 to 7  show wheelchairs in accordance with other embodiments of the present invention; 
         FIGS. 8 and 9  show tug members of an automatic brake of a wheelchair in accordance with embodiments of the present invention; 
         FIG. 10  shows a wheelchair apparatus in accordance with the present invention; 
         FIG. 11  shows a function flowchart of a wheelchair apparatus in accordance with the present invention; and 
         FIG. 12  shows a wheelchair care service network system in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention will be explained with the appended drawings to clearly disclose the technical characteristics of the present invention. However, the embodiments are exemplified only, and do not limit the scope of the present invention. 
     A foldable wheelchair is a dangerous moveable apparatus when its manual brake is not locked. Many wheelchair accidents are caused by the unpredicted movement of the wheelchairs.  FIG. 1  shows a wheelchair  10  with an automatic brake of an embodiment of the present invention. Each wheel  11  of the wheelchair  10  is provided with a brake such as a disc brake, and a tugging cable  12  is connected to a tugging member  13  such as a tugging roller disposed at a side of a seat  14 . The tugging member  13  has a coil spring to pull the cable  12 , and as a result the disc brake is locked. Accordingly, the wheelchair  10  cannot move unless the brake is released. When nobody sits in the wheelchair  10 , the coil spring of the tugging member  13  locks the brake of the wheel  11  as shown in  FIG. 2 . In this embodiment, pulleys  18  are placed at the middle portions of the right and left sides of the seat  14 . A cable  17  is connected to the tugging member  13 , winds around the pulley  18  and extends to be connected to a secure position  20  at another side of the seat  14 . The cables  17  form an interlaced seat weight sensing mechanism  40  to support and sense a wheelchair user. When the user is seated correctly on the seat  14 , the seat  14  is deformed and presses the mechanism of the cables  17 . As a result, tensions are generated in the cables  12  to counteract the elastic force of the coil spring of the tugging member  13 , so as to release the brake as shown in  FIG. 3 . In other words, when the weight on the seat  14  does not exceed a predetermined weight (e.g., the user is not well seated), the brake stops the wheels  11 . When the weight on the seat  14  exceeds a predetermined weight (e.g., the user is well seated), the seat weight detection mechanism  40  tugs and releases the brake of the wheels  11 . The armrests  15  placed at the rear of the wheelchair  10  are provided with manual brake release devices  16 . When the manual brake release device  16  is activated, the tension in the cable  19  will tug the tugging member  13 , and then the cable  12  is tugged to release the brake as shown in  FIG. 4 . 
     In  FIG. 5 , the arrangement of the cables  17  may have some variations. The tugging members  13  are placed at two sides of the seat  14 . Each of the cables  17  is connected to a secure point  20  at another side of the seat  14  to form an interlaced seat weight sensing mechanism  40  to support and sense the user. In this embodiment, the pulleys are not needed, and thus the design is simpler. However, the designer may need to consider the support strength and comfort problem. 
     In  FIG. 6 , wide straps  21  can be used instead of cables to increase user comfort. If the elasticity of the straps  21  is insufficient, the straps must have enough rigidity to prevent the tugging members  13  from being forced out of control by the straps  21  because the influence of the weight is fully absorbed by the deformation of the straps  21 . 
     In  FIG. 7 , a netlike fabric  22  or leather may be used instead of the cables or the straps so as to further increase the user&#39;s comfort. The deformation of the fabric or leather must be minimal in order to retain tight control of the tugging members  13 . 
     Accordingly, the seat weight sensing mechanism of the cables, straps, netlike fabric or leather can automatically verify whether the user is seated in the wheelchair. When the user is well seated, the seat weight sensing mechanism tugs and releases the brake of the wheels. Otherwise, the wheels are locked. 
       FIG. 8  shows the details of the tugging member  13  in accordance with an embodiment of the present invention. A pulley  30  of a roller type is employed to generate and release the tensions in the cables  12 ,  17  and  19 . An end of each of the cables  12 ,  17  and  19  is connected to a secure point of the pulley  30 , and accordingly when tension or compression in the cable  12 ,  17  or  19  is changed, the other two cables will be tugged to lock or release the brake. The center of the pulley  30  has a coil spring  31 , and the elastic force of the coil spring  31  brakes the wheels  11  so that the wheelchair  10  is not moveable when nobody sits in the wheelchair  10 . When tension is generated in the cable  17  or the cable  19  is tugged by the armrest brake release device  16 , the elastic force of the coil spring  31  is counteracted to release the wheels  11 , and therefore the wheelchair  10  becomes moveable. Moreover, the tugging member  13  may use the concentric torque member  32  shown in  FIG. 9 . The concentric torque member  32  includes a coil spring  31  also to achieve equivalent efficacy. 
     The wheelchair automatic brake apparatus can ensure the wheelchair is braked whenever the user is not well seated, so as to reduce the risks of tripping while the user is getting into or out of the wheelchair. The wheelchair automatic brake apparatus can also be foldable. Many people use the wheelchair as a stepping assistant; they stand behind the wheelchair and are supported by the armrests, and step forward by pushing the wheelchair. However, the physical conditions of the users vary, and their abilities to maintain control while pushing the wheelchair are different. Many accidents such as the user&#39;s tripping are caused by an unexpected movement of the wheelchair when the user steps forward while pushing the wheelchair. According to this invention, the brake release device is placed at the armrest, and the user can press the brake release device to release the wheelchair when the user steps forward while pushing the wheelchair. If the wheelchair is out of the user&#39;s control and slips forward, the user no longer holds the brake release device and therefore the wheelchair will be braked automatically. Therefore, user tripping accident due to unexpected movement of the wheelchair can be avoided. Moreover, the care provider can press the brake release device on the armrest to move the wheelchair when needed. 
       FIG. 10  shows an apparatus  50  of the user&#39;s posture detection and warning functions. The seat  51  and the seat back  52  are provided with sensors  53 . The sensors  53  are evenly distributed or locally concentrated in an array or non-array manner, and may be of pressure type, switch type or their combination. A corresponding data processing unit  60  may include a data input interface  61 . If pressure sensors are used, the data processing unit  60  has to have an analog-to-digital conversion interface to convert the analog sensed voltages to digital signals for being processed by the microprocessor  62 . If switch sensors are used, digital interfaces read the voltages of the switch sensors, and the data can be processed in the microprocessor  62  directly. The sensors  53  on the armrests  54  may be pressure sensors or switch sensors to verify whether the user presses the armrests  54  and wishes to stand up or sit down. The manual brake sensor  55  is a switch sensor to verify that the manual brake of the wheelchair is locked. By using the information obtained from the seat  51 , the seat back  52 , the armrests  54  and the manual brake sensor  55 , the user&#39;s intended action and posture can be estimated. A user interface  63  is used for inputting the setting data to the data input interface  61 . For example, the data processing unit  60  is set to receive digital or analog data. Moreover, the data processing unit  60  may further include a wireless transmission module  64  and a warning module  65 . The data obtained by the sensors  53  is processed by the microprocessor  62  to be converted into the information of the user&#39;s postures and actions. The information can be stored locally or transmitted to a remote server through a wireless transmission module  64  for further storage and analysis. If the user&#39;s postures and actions have high risk of accidents, the warning module  65  warns the user and the care provider by sound, light or vibration, and the wireless transmission module  64  sends warning messages to a remote server and a care worker&#39;s portable device for further storage and processing. According to current wireless technology, a wireless transmission module  64  may be a mobile phone. 
       FIG. 11  shows a function flow of the data processing unit  60 . The situations of “non-brake when the user sits down” and “non-brake when the user stands up” are dangerous actions. Many wheelchair users such as aged people cannot control the wheelchair and react effectively. Therefore, if the wheelchair is not braked when a user stands up or sits down, the user may fall down due to an unexpected rush of the wheelchair. According to the variation of the pressures on the seat  51 , the seat back  53  or the armrest  54  or the contours of the buttocks and the back thereon, the user&#39;s intention of whether the user is going to stand up or sit down can be estimated. If the user intends to stand up or sit down, the brake status is checked to ensure the brakes at both sides are locked. If the wheelchair is not braked, the warning module  65  of the data processing unit  60  will generate a warning by sound, light and vibration to remind the user to lock the brakes, and at the same time the wireless transmission module  64  sends a warning to the care provider. Accordingly, the user&#39;s tripping due to an unexpected movement of the wheelchair can be avoided. Table 1 shows the sensed data and the corresponding postures in accordance with an embodiment. 
     
       
         
               
               
               
             
           
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 User&#39;s status 
                 Sensed data 
               
               
                   
                   
               
             
             
               
                   
                 Not using 
                 No pressure on the seat, seat 
               
               
                   
                   
                 back and armrest 
               
               
                   
                 Going to sit down 
                 The front of the armrest is 
               
               
                   
                   
                 pressed, and the front of the seat 
               
               
                   
                   
                 is pressed. 
               
               
                   
                 Seated 
                 The rear of the seat is pressed, 
               
               
                   
                   
                 and the seat back is pressed. 
               
               
                   
                 Going to stand up 
                 The seat back and the rear of 
               
               
                   
                   
                 the seat have no pressure, and the 
               
               
                   
                   
                 front of the armrests are pressed. 
               
               
                   
                   
               
             
          
         
       
     
     Moreover, while the user is seated in the wheelchair, the data processing unit  60  monitors the pressure distribution of the seat  51  and the seat back  52  and the contours of the buttocks and the back to verify whether the user&#39;s posture incurs local pressure, dangerous posture or the like. If a dangerous posture is verified, the warning module  65  of the data processing unit  60  will generate a warning by sound, light or vibration to remind the user of the posture, and the user&#39;s posture data will be transmitted to a care provider by the wireless transmission module  64  and stored in a care service server for further analysis. Table 2 shows the sensed data and the corresponding unhealthy postures in accordance with an embodiment. 
     
       
         
               
               
               
             
           
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                 User&#39;s posture 
                 Sensed data 
               
               
                   
                   
               
             
             
               
                   
                 Local pressure (e.g., 
                 Large local pressure on the seat, 
               
               
                   
                 lean right) 
                 and/or large local pressure on the 
               
               
                   
                   
                 seat back. 
               
               
                   
                 Dangerous posture (e.g., 
                 Only the front of the seat is 
               
               
                   
                 tripping) 
                 pressed, or only the front of the 
               
               
                   
                   
                 seat back is pressed. 
               
               
                   
                 Unhealthy posture (e.g., 
                 The pressure distribution of the 
               
               
                   
                 seated for extended time) 
                 seat, seat back and the armrest 
               
               
                   
                   
                 caused by unhealthy postures 
               
               
                   
                   
               
             
          
         
       
     
     The above two devices constitute a wheelchair apparatus of automatic brake and user posture detection and warning functions, so as to prevent an unexpected rush of the wheelchair by active automatic braking when the user is not well seated, and warn the user of the abnormal behaviors or inform the care provider of the same. Accordingly, the active and passive safety mechanisms can effectively reduce the likelihood of accidents. If one of the two independent mechanisms does not work, the other mechanism still can ensure safety. For example, if the posture detection and warning apparatus does not work, the automatic brake can effectively prevent the user from falling. Conversely, if the automatic brake does not work, the posture detection and warning apparatus can warn the user of unhealthy postures and the abnormal behaviors by sound, light and vibration to avoid dangers. 
       FIG. 12  shows a wheelchair care service network system  80  including the above-mentioned apparatus  50 , a wireless access point  84 , a server  81 , a user interface  82  and a portable device  83 . The wheelchair  50  sends the user&#39;s posture and a warning of dangerous operation to the wireless access point  84  and the portable device  83  of the care provider by wireless transmission. The wireless access point  84  transmits the data to the server  81  by the network for further data processing. The seated time, the user&#39;s posture and the warning message are analyzed in the data processing and the analyzed result is shown by tables or figures, so that the care worker can improve the service and enhance related safety education to prevent the user who is seated in the wheelchair for a long time from having chronic diseases such as bedsores and body deformations and avoid the accidents while the user gets into or out of the wheelchair. The care provider can check on the statistics in the server  81  through the user interface  82  (e.g., a computer) or portable device  83  so as to instantly provide necessary services. In an embodiment, the portable device  83  includes a notebook computer, a personal digital assistant (PDA), a smart phone or a pager. In practice, the portable device  83  could be an example of the user interface  82 . As to the processing for an urgent warning, the wireless transmission module of the wheelchair data processing unit generates a warning, and the warning is transmitted to both the wireless access point  84  and the portable device  83 , so that the care worker within the wireless transmission range can instantly take necessary actions. 
     The wheelchair care service system is developed according to the demand of the wheelchair user of institute type; the automatic brake, the detection of the user&#39;s posture, the estimation of the user&#39;s intention, the data transmission network, the care service server and the display for the care provider are used for resolving the imperative problems of the wheelchair care service system such as how to reduce accidents, the bone deformation due to being seated in the wheelchair for long periods and the task load of the care provider. 
     The above-described embodiments of the present invention are intended to be illustrative only. Numerous alternative embodiments may be devised by those skilled in the art without departing from the scope of the following claims.