Patent Publication Number: US-7594698-B1

Title: Portable seat for a wheelchair

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates generally to wheelchairs and scooters, and, more particularly, relates to a seat of a wheelchair or scooter, and, in greater particularity, relates to means for assisting the user to elevate oneself or to assist the user in removing oneself from the seat. 
   2. Description of the Prior Art 
   Wheelchairs are very important mobility vehicles for persons having a physical condition where mobility is otherwise limited by physical and/or mental impairment. Wheelchairs are present in great numbers in hospitals, nursing homes, rest homes, and at home. Further, there are many reasons to remove oneself from a seated position: to go to bed, to relieve oneself, to change clothes, to take a shower, for medical examinations, etc. 
   Wheelchairs come with many options that can greatly affect the price. Simple wheelchairs may cost several hundred dollars, and more fully accessorized wheelchairs may cost up to one thousand dollars. The addition of an electric drive and seat adjustable features to wheelchairs raise the cost to between 5 thousand to 10 thousand dollars. Another related product is called the electric scooter and an electric power chair. The cost of these varies greatly depending on features, but ranges from about 1 thousand to several thousand dollars. The electric scooter may be used outside and inside. The power chair is usually limited to the home. 
   Wheelchairs vary from simple to complex. A very simple wheelchair is called a transport chair and its main feature is that it is lightweight weighing only about 20 pounds. Rather than having two large wheels, a small wheel is placed on each corner of the frame. The seat is a fabric sling seat and secured to two horizontal seat rail tubes. Two widths are available typically. On more traditional wheelchairs, the end of each seat rail tube is mounted a plastic guide that slides up and down the vertical tubes which form an armrest on the top, that can not be removed. Two crossing pivoted tubes, one end attached to the seat rail tube and the other end to a lower frame tube allow the wheelchair to be folded. It has swing-away footrests. Such a wheelchair is sold by Drive Medical Design and Manufacturing. 
   A more upscale and traditional wheelchair has removable arm rests, a pair of large wheels in the rear and a pair of small wheels in the front, elevating leg rests, swingaway foot rests, fabric sling seat and back and is illustrated by Probasics Model EC10, for example. Additional features of other wheelchairs would include chrome plating; selection of seat widths, ranging from 18 inches to 26 inches; seat depth of 16 inches; a selection of weight capacity; full length armrests. Two pairs of crossed pivoted tubes support the seat rail tubes. In one wheelchair, the seat rail tube is further mounted to a single vertical sliding tube mounted inside a tube secured to the frame. One pair of crossed tubes is used between the sides. As the wheelchair is folded, the seat rail elevates and one end has a plastic guide that travels along a vertical tube where the seat back is secured. 
   Electric wheelchairs are significantly more expensive than regular wheelchairs and cost from several thousand up to almost 10 thousand dollars. These wheelchairs further add many additional features not available otherwise. Several example of such are sold by Invacare as Model Formula TRE, by Pride Mobility Products Corp. as the Jazzy 100, and by 21 st . Century Scientific, Inc., as Model Bounder Plus H-Frame Power. For example, the Bounder comes with a chair seat that can recline, tilt, and elevate. All of these actions are provided by computer controlled electric motors driving crossed tubes under the chair seat. The Invacare model also provides recline, tilt and elevate of the chair seat in various combinations of movement. The elevate mode goes up to 7 inches. The seat fabric in these models are not of the sling design as is typical of the regular wheelchair, but have a cushion mounted in a rigid frame. No model is shown having the ability to just move the seat cushion. 
   For the user who does not require a wheelchair, but still lacks mobility, the electric scooter is an option. The electric scooter provides a cushioned seat mounted to a frame that includes the backrest. The seat may be adjustable in height, but not with a user on the seat. The seat is pivotally mounted to the seat frame for ease of mounting and dismounting. It further may have armrests that can be folded out of the way. Control of the scooter is through a tiller with handle bars with controls thereon. Typically, the scooter has three wheels with the back pair being driven. Such an electric scooter is sold by Pride Mobility Products Corp. as Model Go-Go Ultra. 
   In the standard wheelchairs and scooters, no provision is made for assisting the user in standing or being elevated. Several patents do disclose such means, but do not disclose seat controllable devices or any device that is portable from one wheelchair to another for such a purpose. 
   U.S. Pat. No. 3,985,389 discloses a mechanical/hydraulic elevating means attached to the frame for lifting the wheelchair vertically. 
   U.S. Pat. No. 4,613,151 discloses an electric wheelchair having the seat attached to four pivoting legs to lower the seat and to raise the seat to a standard position. 
   U.S. Pat. No. 4,949,408 discloses an electric wheelchair having a movable back and leg rest that allows the wheelchair to be converted to a horizontal bed for transferring the user to a bed. 
   U.S. Pat. No. 4,993,736 discloses wheelchair with a plurality of inflatable cushions under the seat for raising the seat and back to a higher position as a unit. 
   U.S. Pat. No. 5,108,202 discloses a wheelchair having a mechanical device for moving a sitting patient to a standing position. 
   U.S. Pat. No. 5,520,403 discloses a wheelchair having a complex mechanical device for elevating the seat within the wheelchair. 
   U.S. Pat. No. 5,513,867 discloses a wheelchair having a mechanical device for rotating the seat from the horizontal position to an almost vertical position wherein the user may stand. 
   U.S. Pat. No. 5,613,697 discloses a wheelchair having four hydraulic lifting devices for lifting the wheelchair to a higher position. 
   U.S. Pat. No. 6,431,650 discloses a wheelchair having a single hydraulic pump in the center of the seat frame and further having four tube-in-tube corners for allowing the seat to be raised vertically. 
   U.S. Pat. No. 7,040,641 discloses a user lifting device/hoist attached to the wheelchair, and further has a sliding seat to assist in standing the user. 
   U.S. Pat. No. 7,165,778 discloses a wheelchair having mechanical means to assist in the standing of a user by slanting and raising the seat. 
   These patents are incorporated by reference. 
   Accordingly, there is an established need for an improved mobility device having an optional seat having elevating and tilting features. 
   SUMMARY OF THE INVENTION 
   The present invention is directed at an improved seat for a limited mobility vehicle, i.e., a wheelchair or scooter. 
   The present invention further provides means for using the improved seat on standard non-electric wheelchairs and scooters as well as transferring this improved seat to other similar vehicles. 
   In operation, the present invention allows the user to elevate oneself, tilt the seat, and use the improved seat on standard wheelchairs. 
   In the present invention, an improved seat may be attached to standard wheelchairs and scooters with or without the original seat thereon. It further may be used as a standalone seat in regular chairs where additional assistance is needed to elevate and/or tilt the seat. In most standard wheelchairs the sling seats are made of leather-like materials without any additional cushioning thereunder. This allows for the seat to remain when the wheelchair is folded. This type of seat has no special features to provide comfort and protection to the user and when used, the user&#39;s rear is basically placed in a sling where the weight of the user is support on the seat in basically two locations. 
   In the preferred embodiment, a portable inflatable seat is positioned where the original wheelchair seat is mounted to two seat rail tubes. The portable inflating seat has a lower frame upon which are attached four supporting brackets, one pair on each side. Each bracket fits over the seat rail tube in a manner that allows it to be easily removed for folding of the wheelchair. Different brackets may be used when the original seat remains. Upon the top of the lower frame is stack mounted a plurality of box-like inflatable seat bags. An air pump unit with battery is removably attached to the back of the wheelchair. A control unit is also removably attached to the wheelchair and a control box is attached to the armrest and to the control unit. A hose from the air pump unit is attached to the lowest inflatable seat bag. When turned on, the air pump unit will inflate the seat bags to a predetermined pressure based upon the weight of the user. The user will be elevated to a height of about 6 inches or so. A deflate switch on the control box will allow the bags to deflate in a controlled manner. As an additional feature, a tilt seat bag being of predetermined shape and attached to the top of the highest inflatable seat bag can be inflated also causing the seat to tilt forward allowing the user to more easily dismount. A separate control is provided for the tilt seat bag. Attached to the top bag is a cushion mounted to an upper frame that is more appropriately designed to prevent excessive point pressures to the user&#39;s rear. The portable inflatable seat may also be used on scooters. If the scooter seat is or is not removed, adjustable straps attached to the lower seat frame may be used to secure the portable inflatable seat thereto. 
   In an alternative embodiment, a portable seat is positioned where the original wheelchair seat is mounted to two seat rail tubes. The portable seat has a lower frame upon which are attached four brackets, one pair on each side. Each bracket fits over the seat rail tube in a manner that allows it to be easily removed for folding of the wheelchair. Different brackets may be used when the original seat remains. Upon the top of the lower frame are four pivoted legs. Two legs are positioned as a unit on the front and two legs as a unit on the rear of the frame. A horizontal arm connects the two front legs at the lower part thereof and has a pivoting and threaded drive nut. Another horizontal arm connects the two rear legs at the lower part thereof and has a pivoting and threaded drive nut, being oppositely threaded. A drive screw is mounted to both drive nuts and when rotated the legs are pushed apart in the front and rear direction to raise the seat thereon. The legs at the lower part are mounted in channels in the sidewalls of the lower frame to further secure them. The upper part of each leg is pivotally mounted to an upper frame. The drive screw may be turned by hand or by an electric motor through a control unit having a control box mounted on the armrest and a battery for power removably attached to the back of the wheelchair. An elevation control switch is included in the control box attached to the armrest and to the motor control unit. An alternative embodiment may allow the power to be supplied by an A/C source. The user will be elevated to a height of about 6 inches or so. A lowering switch on the control box will allow the lowering of the seat in a controlled manner. As an additional feature, a tilt seat section may be attached to the upper frame causing the seat to tilt forward allowing the user to more easily dismount. This feature may be activated when the seat is or is not elevated. A tilt control switch is provided for the tilt seat feature in the control box. Between the lower and upper frame is mounted a plastic curtain to prevent fingers and other objects from becoming lodged in the mechanical mechanisms. A cushion is mounted to the upper frame that is more appropriately designed to prevent excessive point pressures to the user&#39;s rear. The portable seat may also be used on scooters. If the scooter seat is or is not removed, adjustable straps attached to the lower seat frame may be used to secure the portable seat thereto. 
   An object of the present invention is to provide a portable seat that may be used on wheelchairs, scooters, and chairs. 
   It is another object of the present invention to provide a portable seat that has independently operated elevating and tilting features. 
   It is a further object of the present invention to provide a portable seat having a seat surface better adapted for long-term use than a standard upholstered sling seat. 
   It is still a further object of the present invention to provide a portable seat that is easily removed and attached to a standard wheelchair, for example. 
   It is yet a further object of the present invention to provide a portable seat that minimizes manufacturing costs. 
   These and other objects, features, and advantages of the present invention will become more readily apparent from the attached drawings and the detailed description of the preferred embodiments, which follow. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The preferred embodiments of the invention will hereinafter be described in conjunction with the appended drawings provided to illustrate and not to limit the invention, where like designations denote like elements, and in which: 
       FIG. 1  is a partial schematic front view of a portable inflatable seat of the present invention; 
       FIG. 2A  is a partial front view of a preferred embodiment of a mounting bracket for a portable seat of the present invention; 
       FIG. 2B  is a front view of another mounting bracket for a portable seat of the present invention wherein the sling seat is not removed; 
       FIG. 3  is a top view of a control unit of the portable inflatable seat of  FIG. 1 ; 
       FIG. 4  is a top view of a control box of the portable inflatable seat of  FIG. 1 ; 
       FIG. 5  is a partial side view of a tilting bag of the portable inflatable seat of the present invention; 
       FIG. 6A  is a side view of a means for mounting a portable seat of the present invention to an electric scooter 
       FIG. 6B  is a partial front view of a mounting bracket as shown in  FIG. 6A  for a portable seat of the present invention on an electric scooter; 
       FIG. 7A  is a partial side view of a portable seat of the present invention in a elevated position; 
       FIG. 7B  is a partial side view of a portable seat of the present invention in the non-elevated position; 
       FIG. 8  is a partial front view of a pair of legs with a connecting member between the legs with a drive nut thereon for a portable seat of the present invention as shown in  FIGS. 7A and 7B ; 
       FIG. 9  is a top view of a screw mounted to two drive nuts of the present invention of the portable seat of  FIGS. 7A ,  7 B, and  8 ; 
       FIG. 10  is a top view of a tilting seat for a portable seat of the present invention; and 
       FIG. 11  is a side view of a drive means for opening the tilting seat for a portable seat of the present invention as shown in  FIG. 10 . 
   

   Like reference numerals refer to like parts throughout the several views of the drawings. 
   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The present invention is directed at a portable seat for a limited mobility vehicle. 
   As a preferred embodiment, the present invention is directed at a portable seating device being inflatable or electro-mechanically driven for use on wheelchairs, scooters, and on other seats where the user needs assistance in being elevated or dismounting. 
   Turning to the drawings, wherein like components are designated by like reference numerals throughout the various figures, attention is initially directed to  FIG. 1  which illustrates by a partial schematic view a portable inflatable seat  100  constructed according to the present invention. 
   As best shown in  FIG. 1 , the portable inflatable seat  100  is inflated by the use of a plurality of stacked rectangular inflatable bags  102 . Although other alternative designs may be used, the preferred embodiment is directed at the portable inflatable seat  100  of  FIG. 1 . 
   In the present invention, the improved seat may be attached to standard wheelchairs and scooters with or without the original seat thereon. It further may be used as a standalone seat in regular chairs where additional assistance is needed to elevate and/or tilt the seat. In most standard wheelchairs the sling seats are made of leather-like materials without any additional cushioning thereunder. This allows for the seat to remain when the wheelchair is folded. This type of seat has no special features to provide comfort and protection to the user and when used, the user&#39;s rear is basically placed in a sling where the weight of the user is support on the seat in basically two locations due to the v-shaped feature of the sling device. 
   In the preferred embodiment, a portable inflatable seat  100  is positioned where the original wheelchair seat  202  is mounted to two seat rail tubes  200 ,  FIGS. 2A and 2B  being of conventional design. The portable inflating seat  100  has a lower frame  204  upon which are attached four supporting brackets  206 , one pair on each side. The lower frame  204  must be of sufficient strength to support the user resting up it. It may be manufactured of lightweight sheet metal or plastic material. Each bracket  206  fits over the seat rail tube  200  in a manner that allows it to be easily removed for folding of the wheelchair, but still provides sufficient support to the user. Further opposite brackets  206  may further be an integral part of a single strap. As seen in  FIG. 2B , the seat  202  has been removed and is normally attached to the seal rail tubes  200  with screws and one or more retainers  208 . Different brackets may be used when the original seat remains such as a bracket  210  that is L-shaped. Further, these brackets  206  or  210  may be removed and replaced with other types of brackets for holding the seat to a scooter with straps, for example,  FIG. 6B . 
   Upon a top surface  104  of the lower frame  204  is stack mounted a plurality of box-like inflatable seat bags  102 ,  FIG. 1 . These bags  102  may be made of a strong and durable fiber cloth and/or plastic material. An air pump unit  106 , being a means of inflating the bags  102  and elevating an upper frame  120  having a cushioned seat  122  thereon, has a battery unit  108  which may be removably attached to the back of the wheelchair upon one of the vertical tubes, not shown. The battery unit  108  may further include means for connecting to an A/C source by plug  128  for converting the A/C power to D/C power and/or for charging the battery unit  108 . The air pump unit  106  may be similar to air pumps used to inflate car tires run off of a car battery, for example, and also includes a pressure sensor  118 . A control unit  110 ,  FIG. 3 , is also removably attached to the wheelchair and a control box  112 ,  FIG. 4 , is removably attached to the armrest of the wheelchair and to the control unit  110 . The control box  112  contains the necessary switches and indicators to operate the seat by the user, and the control unit  110  has the necessary electronics to monitor and control the movement of the seat. Although separate units are shown, these may be combined into one unit that must be mounted on the wheelchair to be within the reach of the user, most typically on an armrest. A hose  124  from the air pump unit  106  is attached to a lowest inflatable seat bag  116 . The pressurized air flowing from one seat bag to the next bag. When turned on, the air pump unit  106  will inflate the seat bags  102  to a predetermined pressure as measured by the pressure sensor  118  in the air pump unit  106  based upon the weight of the user entered into the control unit  110  upon initial setup. The user will be elevated to a height of about 6 inches or so in a horizontal plane. The backrest of the wheelchair does not move in the present invention. 
   Referring to  FIG. 3 , the control unit  110  would include various switches and indicators to operate the portable seat  100 . There is mounted therein a pressure sensitive switch  306  to turn the unit on. A green light  300 , from an LED, for example, would so indicate the “on” condition. A set switch  308  when pressed, for example, would cause an indicator  310 , being a LCD, for example, to illuminate. An adjustment switch  312  would be used to enter the weight of the user. If there was insufficient voltage from the battery  108 , a red light  314  would blink. 
   Referring to  FIG. 4 , a pressure sensitive switch “ON/OFF”  408  is used to turn the seat  100  on with a green light indicator  404  indicating the “on” condition. A raise/lower switch  400  is mounted on the control box  112 . This controls the inflation/deflation of the bags  102  in a controlled manner. A tilt/level switch  402  would start the tilting of the seat. Another push would level the seat. At any time during the inflation, deflation, tilt, or level, a stop/continue switch  406  may be pushed to stop any action occurring and then resume that action upon a second push. All of these devices, switches, indicators, and controls are considered to be conventional and known to one skilled in the art of making control devices for such devices as exercise devices. 
   As an additional feature, a tilt seat bag  500 ,  FIG. 5 , being of predetermined shape and attached to a top of a highest inflatable seat bag  502  can be inflated causing a seat  504  to tilt forward in an inclined plane allowing the user to more easily dismount. The tilt seat bag  500  may be wedge shaped or rectangular shaped as shown. A pressure-opening valve  506  is connected between the bags  502  and  500  so that when a predetermined pressure is obtained in bag  502 , the valve  506  will open to allow the pressurized air to flow into the bag  500 . A separate control switch  402 ,  FIG. 4 , is provided for the tilt seat bag  500  on the control box  112 . Attached to the top bag  502  is an upper frame  120  having a cushion  122  mounted thereto which is more appropriately designed to prevent excessive pressure to the user&#39;s rear. 
   The portable inflatable seat  100  may also be used on scooters. If a scooter seat  600 , partially shown in  FIG. 6A , is removed, adjustable straps  602  attached to the lower seat frame  204  may be used to secure the portable inflatable seat  100  thereto. As seen in  FIG. 6B , the strap  602  is passed through a bracket  608  and may be secured by means of a buckle  606  or other means such as a Velcro-like material. The strap  602  would pass over the frame  604  of the scooter seat, only one rail seen therein. If the scooter seat is not removed, the straps  602  must be sufficiently secured to the flexible scooter seat to prevent the portable inflatable seat from shifting. 
   In an alternative embodiment, a portable seat  700 , partially shown by side view in  FIG. 7A , is positioned where the original wheelchair seat is mounted to two seat rail tubes. The portable seat  700  has a lower frame  702  that is attached to the wheelchair or scooter in a manner similar to the portable inflatable seat  100  as shown above.  FIG. 7A  illustrates the seat in the elevated position, and  FIG. 7B  illustrates the seat in the non-elevated position. 
   Upon a topside  704  of the lower frame  702  are four pivoted legs  706 , only two shown from the side. Two legs  708 , only one shown, are positioned on a front  710  and two legs  714  on a rear  712  of the frame  702 . The legs  706  are pivotally connected to a top frame  716  at each corner thereof. Referring to  FIG. 7A , the lower legs  718  and  802  are mounted in channels  720  and  722  in the sidewalls  724  of the lower frame  702 . The upper part  726  and  728  of each leg is pivotally mounted to an upper frame  716 . The drive screw  900  may be turned by hand or by an electric motor  730 . 
   Referring to  FIG. 8 , a horizontal arm  800  connects the two front legs  708 , for example, at the lower part  802  thereof. The horizontal arm  800  may rotate as mounted therein and has a pivoting and threaded drive nut  804 . Another horizontal arm connects the two rear legs  714 , not shown, at a lower part  718  thereof and has a pivoting and threaded drive nut  902 , being oppositely threaded. Referring to  FIG. 9 , a drive screw  900  is mounted to both drive nuts  804  and  902 , and when rotated the legs are pushed apart in the front and rear direction to raise the seat thereon. As seen therein, the drive screw  900  is oppositely threaded on each half thereof. When in the non-elevated position the drive nuts  804  and  902  are located at the center of the drive screw  900 . An electric motor  730  is located on the back of the lower frame  702  for driving the drive screw  900 . A portion  906  of the drive screw  900  extends from the motor  730  so that an appropriate wrench or tool may be used to manually move the drive screw  900  if there is a power failure or a malfunction in the seat  100 . 
   As an additional feature, a tilt seat  1000 ,  FIG. 10 , may be attached to the upper frame  716  causing the seat to tilt forward from a hinged edge  1002  allowing the user to more easily dismount.  FIG. 11  illustrates a tilt means  1100  having an electric motor  1104  mounted to the upper frame  716  with a drive screw  1106  having a drive nut  1102  thereon. The drive nut  1102  is rotatably mounted to a lower part  1114  of the arm  1112  that is further pivotally mounted  1110  to the back edge of the tilting seat  1000 . The upper part of the arm  1112  is pivotally mounted  1108  to the rear of seat  1000 . This feature may be activated when the seat is or is not elevated. A tilt control switch is provided for the tilt seat feature in the control box. 
   Between the lower and upper frames  704  and  716 , respectively,  FIG. 7A , is mounted a plastic curtain  732  to prevent fingers and other objects from becoming logged in the mechanical mechanisms. A cushion is mounted to the upper frame  716  that is more appropriately designed to prevent excessive pressure to the user&#39;s rear as shown above. The portable seat may also be used on scooters. If the scooter seat is or is not removed, adjustable straps attached to the lower seat frame may be used to secure the portable seat thereto. 
   Since many modifications, variations, and changes in detail can be made to the described embodiments of the invention, it is intended that all matters in the foregoing description and shown in the accompanying drawings be interpreted as illustrative and not in a limiting sense. Thus, the scope of the invention should be determined by the appended claims and their legal equivalents.