US 3627343 A
Description (OCR text may contain errors)
United States Patent Inventor Wilhelm Meyer 3 Kleinbahnhofstrasse, 4973 Vlotho, Weser, Germany Appl. No. 853,035 Filed Aug. 26, 1969 Patented Dec. 14, 1971 Priority Oct. 16, 1968 Austria A10123/68 COLLAPSIBLE INVALID CHAIR 10 Claims, 5 Drawing Figs.
U.S. C1 280/39 Int. Cl B62b 11/00 Field of Search 280/39, 40, 38, 36 B; 297/D1G. 4
References Cited UNITED STATES PATENTS 10/1937 Everest et a1.
2,486,015 10/1949 Everest et a1. 297/D1G. 4 2,618,319 11/1952 Everest et a1. 297/DIG. 4 2,669,289 2/1954 Usher et al 297/DIG. 4 2,930,429 3/1960 Mize 29 7/DIG. 4
Primary Examiner-Benjamin Hersh Assistant Examiner-Robert R. Song Attorney-Steinberg & Blake ABSTRACT: An invalid chair has two side frames supporting a seat, and a wheel on each frame. The frames are joined by two crossing struts, with a joint between said struts at the crossing point which provides two axes of rotation for the struts. One (transverse) axis of rotation enables the frames to rotate relative to each other and thus assist progress over rough ground. The other longitudinal axis of rotation gives scissorslike movement to the struts, enabling the chair frames to be collapsed towards each other for transport.
PATENTED DEC 1 4 ISII SHEET 1 BF 2 INVI'IN'I'OR: Wilhelm Meyer BYI PATENIED mu: 1 4 Ian SHEET 2 UF 2 Fig.5
INVIiN'lURi Wilhelm Meyer HY: ,fllwliu c/gzal COLLAPSIBLE INVALID CHAIR The present invention relates to a collapsible invalid chair, which chair comprises lateral frames adapted to receive the wheels, and connecting struts maintaining said frames at a desired distance apart, which struts are arranged crosswise and, with a scissorslike motion, are displaceable at the crossing point about a common folding axis.
With known collapsible invalid chairs, the chief disadvantage occurs when moving over uneven ground. Tilting of the entire invalid chair occurs due to the rigid connection of the two side frames, and the invalid chair is consequently supported on the ground by only three wheels. Consequently the chair is in danger of tipping over because the frame is rigidly connected together.
Moreover, the two connecting struts holding the frames together are connected rigidly to the frame. Consequently, when the invalid chair travels over uneven ground, the strut connection is subjected to stress, which stress as an alternating load leads to material fatigue. The life of the connecting struts is therefore curtailed.
It is the object of the present invention to provide a foldable invalid chair which obviates the previous disadvantages, is of a durable and stable construction and is able to move more efficiently over uneven ground.
According to the present invention, there is provided a collapsible invalid chair comprising lateral frames which receive the wheels of the chair and struts connecting the frames together and maintaining them at a desired distance apart, which struts are arranged crosswise and are displaceable with a scissorslike motion about a common folding axis at their crossing point wherein the lateral frames are connected together by means of the connecting struts so that they are pivotable vertically relative to each other.
In a preferred embodiment the side frames can be held together by means of a joint arranged in the crossing area (point) so that they can be pivoted vertically relatively to each other; at the same time the connecting struts in the crossing area can be separately constructed and providedin each case displaceably about a pivotal axis extending transversely to the direction of travel, and the axes of rotation may be connected together by means of the folding axis.
The adjacent joint-side ends of the strut shanks forming a connecting strut may be mounted by a bearing sleeve on a common bolt or the like provided as an axis of rotation.
In another feature of the invention the connecting struts may be formed by torsion springs pivotably connected together to the folding axis at the crossing point and rendering possible vertical swiveling (turning) of the frames relatively to each other. I
According to a further feature of the invention the connecting struts may be formed of two torsion springs connected together at the crossing point by means of the folding axis and the strut shanks provided on said torsion springs.
The invalid chair of the present invention is of simple design, easy and economical to manufacture and convenient to maneuver.
An advantageous feature of the present invention is the great adaptability of the invalid chair to the surface over which it is travelling. This is achieved by providing that the two side frames can be pivoted up or down relative to each other. This invalid chair is thus very stable when moving over uneven ground, since the relatively pivotable frames ensure that the chair rests on the ground by four wheels, which obviates the risk of the chair tipping over.
Furthermore, this invalid chair has a durable and stable construction, particularly in the area of the connecting struts. Consequently, the connecting struts are no longer subjected to stress and therefore have a longer life.
Furthermore, the invalid chair according to the present invention has improved mobility and steering properties even in a confined space, which enables the person or the patient in the chair pushing the chair to maneuver the chair with very little effort.
The invention will be further described, purely by way of example, with reference to the accompanying drawings, in which:
FIG. 1 is a side view of a foldable invalid chair in its upright position,
FIG. 2 is a front view of the invalid chair shown in FIG. 1, showing the two side frames, the distance apart thereof being variable, and connecting struts holding the side frames pivotably together in the plane of the frames,
FIG. 3 is a longitudinal section through the invalid chair in a partly folded state,
FIG. 4 is a side view of the same invalid chair with one side frame having been pivoted, and
FIG. 5 is a plan view of a joint connecting the two connecting struts foldably and pivotably together, shown partly in section.
A foldable invalid chair for handicapped persons has two side frames 10, II, the distance apart thereof being variable, which frames are identically constructed and are made of tubes or the like. Mounted on the rear of these side frames l0, 11, are wheels, usually manually actuated driving wheels 12, while at the front of the side frames running wheels 13, pivota ble about a vertical axis, which are of smaller diameter than the driving wheel 12, are provided.
The displaceable connection of the two frames 10, l 1, is effected by means of two connecting struts l4, l5, crossing each other, which are preferably provided in the center area of the frame; these two connecting struts 14, 15, are also preferably tubular or the like, which, when folded, execute a scissors like motion at their crossing point about a common folding axis 16, which is a screw, bolt, pin or the like. The lower ends of the two connecting struts 14, 15, are pivotably mounted at or near the lower edge of the frames 10, 11, preferably on lower supporting tubes 17 provided for the frames 10, II.
The upper ends of the connecting struts 14, 15, are preferably T shaped and may be assembled to form a T shape by providing a seat tube 18 extending at right angles to the longitudinal axis of the struts, which seat tubes 18 are also adapted to receive a seat 19.
Each connecting strut l4, l5, is held on the side frames l0, 11, by means of at least one guide tube or guide rod 21 displaceable in a guide sleeve 20 provided on the inside of the side frames 10, II. The connecting struts 14, 15, are guidably mounted while executing their scissors like movement about the folding axis 16 when the invalid chair is being folded or unfolded in the region of their upper ends, on guide tubes 21 extending in guide sleeves 20.
Preferably, each connecting strut l4, 15, is held on the side frames 10, 11, by means of two guide tubes 21. At the same time, guide sleeves 20 may be provided on the inside of each side frame 10, 11, at both the front and rear thereof.
The two side frames 10, 11, are connected together by mans of the connecting stru s 14, 15, in such a manner that they can be displaced in level relative to one another and are also pivotable relative to one another in the planes of the frames. Thus, on uneven ground, one of the side frames 10 or 11 can be raised or lowered relative to the other frame in such a manner that all the wheels of the chair remain in contact with the ground at all times.
Preferably, the two side frames 10, II, can be raised or lowered one relative to the other by means of a joint 22 pro vided at the crossing area of the connecting struts 14, 15. Furthermore, the two connecting struts I4, 15, are divided at the crossing area and are displaceable about an axis of rotation 23, 24, extending transversely to the direction of travel. The two axes of rotation 23, 24, are connected together by means of the folding axis 16.
The connecting struts l4, 15, are formed of two shanks 14a and 14b, and 15a and 15b respectively. The adjacent ends of shanks 14a and l4bare fixed to bearing sleeves 26, 27, respectively on a common bolt 25 or the like which serves as axis of rotation 23. The adjacent ends of shanks 15a and 15b are respectively fixed to bearing sleeves 28 and 26 on a common bolt 24 or the like which serves as an axis of rotation. The two axes of rotation 23, 24, are traversed by the bolt 16 which forms the folding axis which extends longitudinally in the direction of chair travel. The adjacent bearing sleeves 25 and 26 are disposed one behind the other when viewed in the direction of travel and are each identically formed. Also, the bearing sleeves 27 and 28 are situated one behind the other when viewed in the direction of travel and are identically formed.
The axes of rotation, for example bolts, 23, 24, and the bearing sleeves 25 and 26 enclosing them, of the strut shanks 14a and 15b provided on frame 1 l are traversed by the folding axis 16. Consequently, the bearing sleeves 25 and 26 are connected with the axes of rotation 23, 24, to form one part. The bearing sleeves 28, 27 of the strut shanks 15a, 14b, respectively arranged on the other frame are rotatable therewith about the axes of rotation 23, 24, and prevented from axial displacement with respect to the axes of rotation 23, 24, by limits 30, 29 such as a collar, safety ring, pin or the like, provided on the free ends of the axes of rotation.
The bearing sleeves 25, 26, 27, 28 are preferably formed or circular tubular members and the axes of rotation 23, 24, may be in the form of solid bolts, pins, circular tubular members or the like.
The folding axis 16 and the axes of rotation 23, 24, are detachably mounted in the bearing sleeves 25, 26, 27, 28
The angle between the longitudinal axes of the bearing sleeves 25-28 and the longitudinal axes of the connecting struts is preferably acute. The bearing sleeves are rigidly connected to the adjacent strut shanks 14a, 14b, a, 15b at the joint ends by welding or the like.
The provision of the joint 22 at the crossing point of the two connecting struts l4, 15, makes it possible not only to fold up the chair when it is not in use, but also to swivel the side frames 10, 11, relative to each other within the planes of the frames. Each frame l0, 11, is thus capable of being rotated through approximately [80 about the axes of rotation 23, 24, relative to the other frame. This rotatable arrangement of the side frames 10, 11, makes it possible to compensate for any uneveness of the ground and ensures, in such circumstances, the four-wheel support of the invalid chair on the ground.
ln another embodiment, the connecting struts 14, 15, are formed of torsion springs collapsibly connected to the folding axis 16 at the crossing point of the struts which enables the frames 10, 11, to be vertically swivelled relative to one another.
Furthermore, the connecting struts l4, 15, may be formed of shanks mounted on two torsion springs foldably connected together at a crossing point by means of the folding axis 16 in such a manner that the frames 10, 11, may have their relative spacing changed and may be swivelled relative to each other in the planes of the frames by means of the torsion springs provided as intermediate members.
It is also within the scope of the present invention to form the joint 22 in a different manner. For example, it could be formed as a ball and socket joint or the like which would make it possible for the two frames 10, l l, to be folded together and to be pivoted vertically.
The invalid chair in accordance with the present invention has enhanced stability, particularly in the area of the connecting struts which hold the frames together.
1. A collapsible invalid chair comprising a pair of lateral frames, a chair wheel on each frame, a pair of struts connecting said frames together and maintaining them at a desired distance apart, said struts being arranged crosswise and interconnected at a common horizontal folding axis extending longitudinally in the direction of chair travel so as to be displaceable with a scissorslike motion about said common folding axis at their crossing point, said struts each being divided at said crossing point into shanks, and a swivel joint interposed between adjacent ends of said shanks of each strut, said joint extending transversely with respect to said folding axis and providing for the shanks of each strut pivotal motion between said shanks thereof about an axis transverse to said folding axis and thus between said frames about a horizontal transverse axis passing through said swivel joint.
2. The invalid chair as recited in claim 1, wherein said joint comprises a pivot extending in the direction of travel of said chair whereby said struts may effect said scissors motion to collapse said lateral frames together.
3. The invalid chair as recited in claim 1 and including pivot bolts extending between and through said shanks enabling said struts to move in two degrees of freedom.
4. The invalid chair of claim 3, comprising a bearing sleeve in each strut shank, said bearing sleeve surrounding one of said pivot bolts.
5. The invalid chair of claim 4, wherein the axes of rotation of said bolts and the bearing sleeves enclosing them, of the shanks provided on only one of said frames are traversed by the folding axis.
6. The invalid chair of claim 5, comprising a rotatable mounting on said bolts for the remaining pair of bearing sleeves not traversed by said folding axis, said mountings being provided at the free ends thereof with a movement-limiting collar.
7. The invalid chair of claim 6, comprising means enabling the longitudinal and transverse pivots to be removed.
8. The invalid chair of claim 4 wherein the longitudinal axes of said bearing sleeves extend at an acute angle relative to the longitudinal axes of the said connecting struts, said bearing sleeves being secured to said connecting struts by welding.
9. The invalid chair of claim 1, wherein said connecting struts are formed by torsion springs pivotably connected together to the folding axis at said crossing point, with means enabling said lateral frames to be vertically swivelled relatively to each other.
10. The invalid chair of claim 9 wherein said connecting struts comprise strut shanks located on two torsion springs foldably connected together at said crossing point.