Land vehicles – Wheeled – Extensible
Patent
1986-10-15
1987-09-15
Love, John J.
Land vehicles
Wheeled
Extensible
280242WC, 297DIG4, B62B 1100
Patent
active
046934901
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a collapsible wheel-chair which has a foldable frame structure which can be locked in the unfolded state and which supports the wheels and the back of the wheel-chair and which comprises a box-shaped seat having side wall members which are connected to foldable seat and bottom members and to foldable front and rear wall members.
Wheel-chairs of this type are known from several patent specifications, e.g. Swedish patent specification No. 161,002, German Auslegeschrift No. 1,176,315, British patent specification No. 711,448, and U.S. patent specifications Nos. 2,522,729, 2,592,405 and 3,337,261. Most of these collapsible wheel-chairs have a frame composed of a number of rods which are pivotally interconnected, such that the wheel-chair can be collapsed by the rods forming a hinge system. As a rule, the seat and back portions are made of strong woven fabrics but at least the seat portions have sometimes consisted of rigid components. Although British patent specification No. 711,448 does not relate to a collapsible wheel-chair but to a collapsible perambulator or go-cart, the system is the same as in the above-mentioned wheel-chairs.
The known wheel-chairs have several drawbacks in common. In most cases, they are quite heavy but, above all, they are rather bulky also when folded up. Often, it is also necessary to remove different parts before the chair can be collapsed, and the back portions made of fabric are often uncomfortable for the person sitting in the chair. Therefore, there is a demand for rigid panels as back portions, which has not been practicable in known constructions. In many cases, use has also been made of seats of woven fabric, this being also uncomfortable. Some of the known constructions have used rigid seats, but it has then been necessary to remove or raise these seats in a separate operation before the wheel-chair is folded up. Another drawback inherent in known collapsible wheel-chair constructions is that a load affecting the back of the chair has given rise to substantial stresses at the corners of the box-shaped structure forming the frame or body proper. Such substantial stresses have necessitated larger dimensions and, hence, have entailed a weight increase of the construction.
One demand placed on present-day collapsible wheel-chairs is that they should have a small width in the collapsed state, a contemplated overall width being 15-25 cm, including the wheels. It is a further desire that the wheel-chairs should have a smaller length in the folded state than in the unfolded state. This has not been achieved in known collapsible wheel-chair constructions.
One of the reasons why it has not been possible to achieve a small width of known wheel-chairs when collapsed is that the wheels usually have a driving ring which is mounted outside the wheel rim. This driving ring projects outside the tyre and, therefore, has contributed to an unnecessarily large width of the collapsed chair. One object of the invention therefore is to provide a movable driving ring for the two large wheels of the wheel-chair.
Another object of the invention is to provide a collapsible wheel-chair which is provided with a rigid back which should preferably also contribute to the stability of the wheel-chair when in the unfolded or raised state. Yet another object of the invention is to provide a wheel-chair which has great stability in the unfolded state but also low weight and small size in the collapsed state.
Further objects of the invention will appear from the following description.
The above-mentioned and other objects of the invention are achieved if the collapsible wheel-chair of the type mentioned in the introduction to this specification is designed as recited in the main claim. Thus, the wheel-chair according to the invention has a foldable frame structure which can be locked in the unfolded state and which carries the wheels and the back of the wheel-chair. In the collapsed state of the chair, all fixed parts are folded up between the wheels of the wheel-chair. The fr
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patent: 4273350 (1981-06-01), Williams
patent: 4625984 (1986-12-01), Kitrell
Loodberg Jan A. T.
Siwersson Olle L.
AB Scaniainventor
Love John J.
McGiehan Donn
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