Rotational Motor The motor is firmly attached to the frame of the upper platform and connected to the 12 V DC power supply. The shaft runs parallel to the radius of the rotational portion of the platform. This motor turns the platform using a friction-drive mechanism, contacting the underside of the steel circle near the edge of the disk. This serves to reduce the force necessary to turn the disk, and slows the rotation of the patient to the desired speed. The rotational motor will possess a clutch mechanism that will cause the motor to slip if too much weight is being applied to the disk. This clutch would serve as a safety mechanism by alerting the user that too much weight is being applied when rotation is not functioning and help avoid motor burn-out under excess stress.National DesignCompetitionDisabled PatientPositioning SystemTeam members:Ben MogaTom PearceJoel RotroffHani Bou-ReslanAdvisor:Mitch TylerAbstract:Hospitals, clinics, and dental care facilities require a method to provide elevation and rotation to wheelchair patients for positioning near vital equipment. Currently there is noexisting device that can provide this motion. The goal of this project is to create a transportable platform that is capable of lifting a wheelchair and its occupant 3 in. to 9 in.(76.2 mm to 228.6 mm) above ground level and provide 360° of rotation. The device needs to be controlled by either the patient or doctor. The current design features two platforms connected by scissor jacks. In operation, the lower platform rests on the floor. The upper platform is translated vertically by two hydraulic cylinders that receive power from a hydraulic motor running off a 12-V rechargeable battery. Rotation is performed by a motor inside the system and is powered by the same battery. Transportation of the device is accomplished by raising the system onto four wheels when the platform is in thelowered position.Field of Invention:The Disabled Patient Positioning System is intended for use in hospitals and dental care facilities. The device allows wheelchair-bound persons and others with limited mobility greater access to health care procedures. This goal is accomplished by reducing mobility-related barriers to certain types of diagnostic and treatment tools.Some patients, specifically those using wheelchairs and other mobility aids, are severely limited in their ability to adjust the position of their bodies. For example, a person in a wheelchair may be unable to stand, thereby limiting the vertical position of the body to that dictated by the chair. It can also be difficult for these patients to use traditional positioning aids such as a dentist’s chair or an exam table. In addition, adjusting the angle of the body provides other challenges. With the help of a doctor, nurse, or orderly, some control of the direction of the patient is obtainable. However, in close proximity to medical equipment, precise control of a wheelchair can be difficult and frustrating. Someexamples of uses for the Disabled Patient Positioning System include height adjustments for dental care, positioning near X-ray machines in both hospitals and dental care facilities, and positioning near mammography machines in hospitals.Background:Research was conducted on existing wheelchair lift devices. The lifts found were intended for both commercial and residential uses. All platform lift devices researched were capable of vertical translation. However, none of the devices found allowed for controlled rotation. The main functions of current platform devices are to vertically translate the wheelchair and its occupant into cars or up stairs. Furthermore, the devices were bulky and in most cases were fixed to operate in a permanent location. This feature makes relocation for use in multiple settings very difficult. Also, most platform devices researched operated on an AC power supply. To be ideally suited for use in a hospital setting, the proposed device needs to be space efficient, transportable and able to operate on a rechargeable, DC power supply.One example of an existing platform device is shown in figure 1. This device is capable of vertical translation only. It is currently used in schools and other buildings, and is not referenced for hospital use. The elevation time for this device is around 20 seconds for a maximum height of 5.48 ft. (1.67 m.) The device has a lifting capacity of 600 lbs. and has been tested for 3000 lbs. The device weighs approximately 270 lbs. The dimensions for the device during transportation and storage are 37.5 in. x 72 in. (952.5 mm x 1828.8 mm) (Adaptative Engineering LTD., 2003). (a) (b)Figure 1: The Mobilift CX, shown in an operational state (a), is one example of an existing wheelchairlifting device. The dimensions of this device (b) are shown in the illustrated top view.Invention summary:The proposed design has six key components, which are: 1. Base: Provide support to the upper frame during normal operations.2. Platform: Secures the wheelchair, provides rotational motion, and transmits force to the lifting mechanism.3. Lifting mechanism: Allows the upper frame to translate vertically and provides the necessary support to maintain elevation.4. Rotational motor: Rotates the circular portion of the upper platform, where the patient is located. Attached permanently to the upper frame.5. Control interface: Allows remote control of both vertical position and rotation.6. Transportation/Accessibility: Gives access to the widest number of patients possible and allows the device to be easily transported between locations.Base Shown in figure 2, the base of the device will consist of a 32 in. x 36 in. (812.8 mm x 914.4 mm) rectangle made from rectangular steel tubing. The steel pipe is 1.25 in. (31.75 mm) in the vertical direction and 2 in. (50.8 mm) in the horizontal direction with awall thickness of 0.0833 in. (2.12 mm). The lifting mechanism will be attached to interior of the base. An additional section on one of the shorter sides of the rectangle willbe added, increasing the overall length. This piece (left-most part in figure 2b) houses the12-V power supply and hydraulic motor. The exact dimensions of the housing depend onthe size of the battery and hydraulic pump, which have not been determined. A hinged ramp will be placed opposite the housing. The ramp will have the ability to lock into a vertical position (figure 5b) for use in transporting the system.
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