The Structure of Manual Wheelchair
Big wheel
Carrying the main weight. There are several types of wheels with diameters of 51, 56, 61 and 66 cm. In addition to a few use environment requirements and the use of solid tires, pneumatic tires are often used.
Small wheel
There are several diameters of 12, 15, 18, and 20 cm, and small wheels with large diameters can easily overcome small obstacles and special carpets. However, the large diameter makes the space occupied by the entire wheelchair larger, making it inconvenient to move. The normal small wheel precedes the large wheel, but in wheelchairs for paraplegics of the lower limbs, the small wheel is often placed after the large wheel. It should be noted that the direction of the small wheel should be perpendicular to the large wheel during operation, otherwise it is easy to fall over.
Hand wheel
Unique to wheelchairs, the diameter is generally 5cm smaller than the large wheel. When hemiplegia is driven with one hand, a smaller diameter is added for selection. The hand wheel rim is generally directly driven by the patient. If the function is not good, it is easy to drive, and the following methods can be modified: ⑴ Add rubber on the surface of the hand wheel rim to increase the grinding force. ⑵ Increase the knob around the hand wheel. There are several types of push handles: ① Horizontal push handles. Used for C5 spine injury. Therefore, when the biceps are sound, the hand is placed on the handlebar, and the elbow flexion force can push the cart forward. If there is no horizontal push, it cannot be pushed. ② Push the handle vertically. Used when rheumatoid arthritis has limited shoulder and hand joint movement. Therefore, the horizontal push bar cannot be used. ③ Bold push. It is used for patients with severely restricted finger movement and not easy to make a fist. It is also suitable for osteoarthritis, heart disease or elderly patients. (The hand-held wheelchair is driven by hand instead of the hand wheel)
Tire
There are three types of solid, inflatable inner tube and tubeless inflatable type. The solid type walks faster on flat ground and is not easy to burst and easy to push, but it is not easy to pull out when it is vibrated on uneven roads and is caught in a groove with the same width as the tire. The vibration is smaller than the solid one; the tubeless inflatable type will not puncture because there is no tube, and the inside is also inflated and comfortable to sit, but it is more difficult to push than the solid one.
Brake
The big wheels should have brakes on each wheel. Of course, if the hemiplegic can only use one hand, he has to use one hand brake, but it can also be equipped with an extension rod to control the brakes on both sides. There are two types of brakes: (1) Notched brakes. This brake is safe and reliable, but more laborious. After the adjustment, it can also be braked on the slope. If it is adjusted to level 1, it cannot be braked on the flat ground. It is invalid. ⑵ Toggle brake. Using the principle of levers to brake through several joints, the mechanical advantages are stronger than notched brakes, but the failure is faster. In order to increase the patient's braking force, an extension rod is often added to the brake, but this rod is easy to be damaged, and infrequent inspection will affect safety.
Chair Seat
Its height, depth and width depend on the patient's body type, and its material texture also depends on the disease type. Generally, the depth is 41, 43cm, the width is 40, 46cm, and the height is 45, 50cm.
Seat Cushion
In order to avoid pressure ulcers, pay attention to the mat. It is possible to use eggcrate or Roto mats. This mat consists of a large piece of plastic with a large number of papillary plastic hollow columns with a diameter of about 5 cm. Each column Both are soft and easy to move. After the patient sits on the pressure surface, the pressure surface becomes a large number of pressure points, and the patient moves slightly. The pressure point changes with the movement of the nipple, so that the pressure point can be continuously changed, avoiding frequent pressure on the same The area causes pressure sores. If the above mat is not available, a layered foam should be used. The thickness should be 10cm. The upper layer should be 0.5cm thick high-density polyurethane foam. Those with density have strong support, while those with medium density are soft and comfortable. In the sitting position, the pressure of the ischial tuberosity is very large, often exceeding the normal capillary end pressure by 1 to 16 times, and is prone to ischemia to form pressure sores. In order to avoid excessive pressure here, often dig a piece of the mat at the corresponding place to make the ischial tuberosity overhead. When digging, the front should be 2.5cm in front of the ischial tuberosity, and the side should be 2.5cm outside the nodule. The depth is about 7.5cm, the mat is concave after digging, and the notch is behind, if the above mat is used to add a cut, it can effectively prevent the occurrence of pressure sores.
Leg support and leg support
The leg supports can be either across the sides or separated on both sides. Both types of supports are ideal for swinging to the side and detachable. Attention must be paid to the height of the footrest. If the foot support is too high, the hip flexion angle is too large, and the weight is more added to the ischial tuberosity, which is likely to cause pressure sores there.
Backrest
The backrest is tall and low and can be tilted or not tilted. If the patient has a better balance and control of the torso, a wheelchair with a low backrest can be used to make the patient more mobile. On the contrary, high-back wheelchairs should be used.
Armrest
Generally, it is 22.5 ~ 25cm higher than the seat surface of the chair, and some armrests can be adjusted in height. You can also put a lap board on the arm rest for reading and dining.
Skirt Board
According to different users, the skirt board and skirt net can be selected to prevent the user's skirt or swing from getting caught in the wheel.
