Structure composition of manual wheelchair

Manual wheelchair structure

The manual wheelchair is generally composed of seven parts: push hand, wheelchair frame, wheel, brake device, anti backward device, seat and pedal.

1. Big wheel

It carries the main weight. The diameters of wheels are 51, 56, 61 and 66 cm. In addition to a few use environment requirements and use solid tires, more pneumatic tires.

2. Small wheel

There are 12, 15, 18 and 20 cm in diameter. The small wheel with large diameter is easy to cross small obstacles and special carpet. But the diameter is too big, the space occupied by the whole wheelchair becomes larger, and the movement is not convenient. The normal small wheel is in front of the big wheel, but in the wheelchair for lower limb paraplegia, the small wheel is often placed behind the big wheel. It should be noted that the direction of the small wheel should be perpendicular to the big wheel, otherwise it is easy to topple.

The image was provided by registered user "Jane" and the copyright notice was sent back

3. Handwheel ring

It is unique to wheelchair, and its diameter is generally 5cm smaller than that of big wheel rim. When hemiplegia is driven by one hand, a smaller diameter is added for selection. The handwheel ring is generally pushed directly by the patient. If the function is not good, the following changes can be made for easy driving:

(1) Add rubber on the surface of handwheel ring to increase friction force.

(2) Add a push knob around the wheel rim.

There are several types of push handles

① Horizontal push handle. For C5 spinal injury. Therefore, when the biceps brachii is healthy, put your hand on the handle and push forward by bending the elbow. If there is no horizontal push handle, it cannot be pushed.

② Vertical push handle. It is used for rheumatoid arthritis when shoulder and hand joint activity is limited. The horizontal push handle cannot be used at this time.

③ Bold push handle. It can be used in patients with severely limited finger movement and difficult to clench. It is also suitable for osteoarthritis, heart disease or elderly patients.

4. Tires

There are solid, inflatable tube and tubeless inflatable three. The solid type walks fast on the flat ground and is not easy to explode and push, but it vibrates heavily on the uneven road and is not easy to pull out when it is stuck in the groove with the same width as the tire; The ones with inflatable inner tube are difficult to push and easy to puncture, but the vibration is smaller than that of the solid ones; The tubeless inflatable type is more difficult to push than the solid one because it can't puncture, inflate the inside and sit comfortably.

5. Brake

The big wheels should have brakes on each wheel. Of course, when hemiplegic people can only use one hand, they have to use one hand brake, but they can also install extension rods to control the brakes on both sides.

There are two types of brakes:

(1) Notched brake. This brake is safe and reliable, but it is more laborious. After adjustment, it can also be braked on the slope. If it is adjusted to level 1, it will be invalid if it cannot be braked on the flat ground.

(2) Elbow brake. Using lever principle and braking through several joints, its mechanical advantage is stronger than notch brake, but its failure is faster. In order to increase the patient's braking force, we often add an extension rod on the brake, but this rod is easy to be damaged. If we don't check it often, it will affect the safety.

6. Chair seat

Its height, depth and width depend on the patient's body shape, 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.

7. Cushion

In order to avoid pressure sores, great attention should be paid to the cushion. Egg crate or roto cushion may be used as far as possible. This kind of cushion is composed of a large piece of plastic with a large number of papillary plastic hollow columns about 5cm in diameter. Each column is soft and easy to move. After the patient sits on it, the pressure surface becomes a large number of pressure points. When the patient moves a little, the pressure points change with the movement of the nipple, In this way, the pressure point can be changed continuously to avoid pressure sore caused by pressing the same part frequently. If there is no such cushion, then it is required to use layer foam plastics. The thickness should be 10cm, the upper layer is 0, 5cm thick high density polychloroformate (polyarethane) foam plastic, the lower layer is the same density plastic with medium density, the high-density support is strong, the middle density is soft and comfortable. In the sitting position, the pressure of the ischial tubercle is very high, often 1-16 times higher than the normal capillary pressure, which is easy to form pressure sores due to ischemia. In order to avoid excessive pressure here, we often dig a piece on the corresponding cushion to make the ischial tubercle overhead. When digging, the front should be 2 or 5 cm in front of the ischial tubercle, and the side should be 2 or 5 cm outside the tubercle, with a depth of about 7 or 5 cm. After digging, the cushion is concave, and the gap is behind. If we use the cushion and incision, we can effectively prevent the occurrence of pressure sore.

8. Foot support and leg support

Leg support can be across the two sides, or separated from the two sides, both of which can swing to one side and can be removed for the best. Pay attention to the height of the foot rest. If the foot support is too high, the hip flexion angle will be too large, and the weight will be more added to the ischial tubercle, which is easy to cause pressure sores.

9. Back rest

The back can be divided into height, tilting and non tilting. If the patient has a good balance and control of the trunk, the wheelchair with low back can be selected to make the patient have a greater range of motion. On the contrary, we should choose high back wheelchair.

10. Armrest or armrest

Generally, it is 22, 5 ~ 25cm higher than the seat surface, and some arm brackets can be adjusted. In addition, a lapboard can be built on the arm bracket for reading and dining.

From the Internet