GB2133748A

GB2133748A - Foldable push-chair

Info

Publication number: GB2133748A
Application number: GB08228935A
Authority: GB
Inventors: Arthur Tayler
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-10-09
Filing date: 1982-10-09
Publication date: 1984-08-01
Also published as: GB2133748B

Abstract

A push-chair comprises a foldable frame supported by four ground- engaging wheels, the frame members on each side of the push-chair forming a foldable parallelogram which,when unfolded, enables one pair of parallel members to stand generally upright and define respectively the seat back 31 and the front rail 21 of the chair, whilst the other two parallel members run generally horizontally to define respectively the seat base and the arm rail 27 of the chair; and each wheel is carried on a limb 13 which, in use, projects from the base of the chair seat and which, when not in use, can fold up against the underside of the seat about an axis running along the push-chair. Preferably the wheels are positively prevented from folding against the underside of the chair seat until the parallelogram frames have been folded, eg by a downward extension at the front rails 21. <IMAGE>

Description

SPECIFICATION Foldable push-chair The invention relates to foldable push-chairs.

In modern forms offoldable push-chair, the chair frame and wheels can collapse transversely to reduce the unfolded width of the chair, and the transversely folded stackof members can sometimes then be folded again lengthwise to effectively halve the length ofthe chairfortransport. In such known chairs, the ground-engaging wheels generally maintain their in-use orientation relative to the chairframe mem bers, and the push-handle, whilst often able to be telescoped, will typically form an interlinked part of the folding frame mechanism.

Those chairs which cannot be folded lengthwise as well as transversely present a relatively lengthy folded bundle which can be difficultto get into a car boot.

Those chairs which can fold lengthwise, as well as folding transversely, have to incorporate relatively complex folding mechanisms. The invention seeks to provideafoldable push-chairwhosefolded length can be minimised withoutthe use of an unnecessarily complicated folding mechanism.

The inventive concept is based on the realisation that this object can most readily be achieved if the wheels, as they fold, do not maintain their orientation relative to the frame members, but instead fold independentlyofthose members and into a position generally flat againstthe underside ofthe chair seat.

The chairframe itself can then fold flat againstthetop of the chair seat, and the entire chair then occupies substantially the same plane without any need to fold the chair transversely.

Thefolding mechanism is thereby greatly simplified, butthechairstillfolds into an acceptably compact state. The overall aspect ofthe folded chair is square, ratherthan elongate, and this overall shape can most readily be fitted into confined spaces for transport.

A push-chair embodying the invention comprises a foldable frame supported, in use, by four groundengaging wheels, and the wheels rotate about respective axes which in use are substantially horizontal and run parallel to one another across the chair; the frame members on each side of the push-chairform a foldable parallelogram which, when unfolded, enables one pair of parallel members to stand generally upright and define respectively the seat back and the front rail ofthe chair, whilst the other two parallel members run generally horizontally to define respectivelythe seat base and the arm rail of the chair; and each wheel is carried on a limb which, in use, projects from the base of the chair seat and which, when not in use, can fold up against the underside ofthe seat about an axis running along the push-chair.

Preferably the wheels are positively prevented from folding againstthe underside of the chair seat until the parallelogram frames have been folded. One advantageous way of doing this is to extend one or both of the normally upright frame members (ie.those defining the back rest and front rail) down beyond the pivots which attach those members to the seat base rails, in such a way that the extended portions bear against, and space apart, the facing surfaces of each pair ofwheel-carrying limbs when the chairframe is unfolded, whilst automatically swinging out of the path of folding movement ofthe wheel-carrying limbs as the frame issubsequentlyfolded.

If both the wheels on one side of the frame are carried in limbswhich areconnected so astofold and unfold together, only one ofthe normally upright frame members on that side need extend beyond its seat base pivot in orderto prop those wheels upright when the push-chair is unfolded.

The downward-extended front rail portions can advantageously be broughttogethertoform a foot rail and/orto carry a foot board forthe chair occupant.

Advantageouslythewheel-carrying limbs are spring-biassed towards their folded positions. The springs can then do away with any need to positively lock the wheel-carrying limbs againstthe underside of the chair seat when the push-chair is being transported and not used for carrying an occupant.

In practical embodiments of the invention, the chair frame will usually incorporate meansto iockthe frame members in an unfolded state or in a succession of partly-unfolded states. Such means could comprise a hand-knob, tightening or untightening one of the frame pivots. Preferably, and advantageously, however,the locking means comprises a link which joins two adjacentframe members and has a lost-motion connection which allows the frame members to fold and unfold whilst being lockable to hold the members in a select position or positions relative to one another.

The link may be a rigid link, fixed to one frame member and slotted to slide back and forth about a pivot on the adjacent member which can be tightened and untightened bya locking knob but which is not one oftheframe pivots.

The push-chair may have a push-handle, projecting beyond the seat back and possibly of adjustable projecting length asforexample by telescoping. In another advantageous feature ofthe invention, the handle pivots and/orfolds flat into the general folded plane of the push-chair but its pivoting and/or folding movement is independent ofthefolding movement of the rest ofthe frame. If the handle does not form an integral linked partofthe main folding frame mechanism, the design of the folding mechanism is again simplified.

The handle may advantageously be an inverted U-member, each ofwhose opposite ends pivots about a respective one of the locking-knob pivots referred to above, and which can be locked by those knobs in selected folded or unfolded positions.

One push-chair embodying the invention is shown, byway of example only, in the accompanying drawings. It is currently the best way known to the applicant of putting the invention into practice. It will now be described with reference to those drawings.

In the drawings, Figure 1 showsthe push-chair in side-elevation, whilst Figure 2 shows the same push-chair drawn to the same scale and viewed in front end elevation. Both Figures 1 and 2 indicate the way in which the push-chairfolds fortransport.

The push-chair consists essentially of a tubular frame-work supported on fourfree-running wheels and incorporating a canvass seat. The framework consists of several sub-parts, and will be described in detail. Each of the wheels is referenced 11 in the drawings and is a conventional rubber-tyredwheel freely rotatable about its respective pivot 12. The canvass seat is not shown or referenced in the drawings, but will be referred to as the description of the framework construction proceeds.

The two wheels in-line along each side ofthe push-chair are carried in a frame 13. The frame 13 is generally U-shaped when viewed from the side, as in Figure 1, and is also U-shaped when viewed in end elevation as in Figure 2. It is pressed from steel or another suitable material. One oftheseframes 13 is carried on each longitudinal side of the push-chair.

A pin 14 connects the back end region of each frame 13 to one respective end of a U-shaped tubularcross member 15. Another pin 16 connectsthe front end region of each frame 13to one respective end of a side member 17 which is generally L-shaped when viewed fromthe side as in Figure 1 .There are two of these side members 17, and they arejoined across their aligned back ends by tube 15 and across their front ends by a tube 18 parallel with the cross member 15. The components 15,17 and 18 make up the seat or base portion ofthe push-chair frame.

Atorsion spring 19 acts between the front end of its associated frame 13 and the adjacent pin 16. There are thustwo ofthese torsion springs, one coiled around each pin 16. The spring-urge the frames 13 to fold towards one another, as indicated by arrows A in Figure 2. With the push-chair unfolded and in use, the frames 13 are kept apart and in their Figure 2 position bythe front portion of the push-chair frame, which will now be described.

Thefrontframe portion consists of opposite spaced L-shaped tubes 21 joined by a straight portion 22 to form a framework which, when viewed as in Figure 2 from the front of the push-chair, is U-shaped. This U-shapedfrontframeportion is pivoted at 23 to each ofthe side members 17. The straight base 22 of the U carries a footboard and toeboard unit 24 which is held on the bar22 by clip 25 and which, with the chair unfolded and in use as illustrated in the drawings, rests on stub-tubes 26 which are welded to the bar 22 and which project parallel with one another at right angles to the axis of the bar 22.

A single member 27 defines the opposite arms and the horizontal back rail ofthe push-chairframe. The member 27 is U-shaped when viewed from above. It is pivoted at 28 to each of the front frame portion sides 21, and it is also pivoted at 29 to another U-shaped hoop 31 which defines the back rest of the push-chair frame and which is itself pivoted at 32 to the base side members 17.

Apush-handleoftelescopicdesign completes the chair frame as'embly. The main part of the handle is referenced 32 and is again U-shaped when viewed as in Figure 2. Each limb of the U-handle 32 telescopes over a respective straighttube 33, and a spring-loaded pin fitting indicated at 34 engages in one of a succession of detents drilled in the limb of the handle 32to enable the effective length ofthe handle to be increased or decreased. The design of these springloaded detent mechanisms can be conventional, and is not particularised here.

The protruding innertelescopic parts 33 ofthe push-handle are each pivoted at35 to a respective one ofthe side rails 17 ofthe frame. A hand-knob 36 can be alternatively tightened or released to lockthe push handle 32,33 at at a desired angle in relation to the frame side members 17, as shown in Figure 1, orto release the handle and allow itto be moved to another angle relativetothoseframeside members.

Another hand-knob 37 similarly allowsthe angleof the frame back rest 31 in relation to the frame side members 17 to be selected and set. A bar 38 extends from the same pivot as the knob 37, and is slotted as indicated in Figure 1 along the greater part of its length. The bar 38 terminates at the pivot 35. The two pivots 35,37 hold the bar38 between them butallowit to slide, when both knobs 35,37 are untightened, to close or open the angle defined between the back rest 31 and side member 17.

The canvass seat, although not illustrated, would be a flat band of material occupying the greater part of the width ofthe push-chairframe, ie. the gap between the opposite limbs of the back rest 31,and would be tunnelled and stitched around the top ofthe back rest to run down in front limbs 27 and 15, be clipped to each pivot 32 and then generally horizontally forward from those clips to be tunnelled and stitched around the front cross bar 18 which spans the frame along the pivot axis 23.

With the push-chair unfolded and in use, as illustrated in the drawings, and with hand-knobs 35,37 tightened, the pivoted push-chair frame is held rigidly open whilst the two spring-loaded wheel-carrying frames 13 are kept apart and held vertical. A retaining strap, not illustrated, maybefittedto preventeach frame 13from inadvertently swinging outward (ie.

clockwise in Figure 2) beyond its intended vertical position. The telescopic handle 32 would be set at an extension comfortable forthe chair pusher.

To fold the push-chairfortransport, knobs 35,37 are untightened. The frame, between the pivots 23,28,29 and 32, then effectively constitutes a deformable parallelogram linkage which can be swung shut by folding it clockwise when viewing it in the Figure 1 orientation. The front side rails 21 and back rest 31 swing about pivots 23 and 32 respectivelyto bring the member 27 down flat against and substantially in the plane ofthetops ofthe side rails 17. The slotted bars 38 slide along pivots 35 as they move with the back rest 31. The handle 32,33 can be swung separately down flat againstthe top of the side rails 17, by moving it clockwise about its pivot 35, and can then be telescoped in on itself to minimise its projecting length from those pivots.

As the side rails 21 pivotabouttheaxis23,the bottom portions ofthose side rails will automatically swing clockwise (when viewed as in Figure 1) and up out oftheway of the frames 13. The springs 1 9then urge the frames 13 to fold flat inwards against one another, as indicated by arrows A in Figure 2. As the frames 13 move in towards one another, they push against the toe board 24 and cause it to pivot on its clips 25 aboutthe bar22.

The folded push-chair th us assumes the configuration indicated in faint line in the drawings, and if knobs 35,37 are then tightenedthechairis locked in its folded state and cannot inadvertently open.

Throughoutthefolding, and any subsequent unfolding, movement, the top ofthe back rest 31, and the front cross bar 18 spanning axis 23, both remain at an unvarying distance from the pivots 32. The canvass seat, although clipped at each opposite side to pivots 32, is not led around orfixed to cross-member 15.

Thus the seat material remains unstretched during folding and unfolding of the push-chairframe, whilst conforming automatically to the contours of the seat occupant in use.

In the push-chair described and illustrated, the knobs 37 act as safety locks. Once the main pivot knobs 35 have been tightened, the knobs 37 are to some extent redundant; but should the knobs 35 inadvertently become untightened then the tightened knobs 37 and bars 38 prevent the chair frame from folding.

In practice, the handle 32 would project somewhat farther than that illustrated, to give a reach comfort able forthe average intended pusherofthe chair.

CLAIMS (Filed on 3.8.83) 1. A push-chair in which a foldable frame is supported, in use, byfourground-engaging wheels, and the wheels rotate about respective axes which in use are substantially horizontally and run parallel to oneanotheracrossthechair; theframe members on each side ofthe push-chairform a foldable parallelogram which, when unfolded, enables one pair of parallel members to stand generally upright and define respectively the seat back and the front rail of the chair, whilst the other two parallel members run generally horizontally to define respectively the seat base and the arm rail ofthe chair; and each wheel is carried on a limb which, in use, projects from the base ofthe chair seat and which, when not in use, can fold up against the underside ofthe seat about an axis running along the push-chair.

2. A push-chair according to Claim 1 and in which the wheels are positively prevented from folding against the underside of the chair seat until the parallelogram frames have been folded.

3. A push-chair according to Claim 2 and in which one or both ofthe normally uprightframe members (ie. those defining the back rest and front rail) extends down beyond the pivots which attach those members to the seat base rails, in such a way thatthe extended portions bear against, and space apart, the facing surfaces of each pair ofwheel-carrying limbs when the chairframe is unfolded, whilstautomatically swinging out of the path of folding movementofthewheel- carrying limbs as the frame is subsequently folded.

4. A push-chair according to Claim 3, and in which both the wheels on one side of the frame are carried in limbs which are connected so as to fold and unfold together, with only one of the normally upright frame members on that side extending beyond its seat base pivot in orderto prop those wheels upright when the push-chair is unfolded.

5. A push-chair according to Claim 3 or Claim 4 and in which the downward-extended front rail portions are brought togetherto form a foot rail and/orto carry a foot board for the chair occupant.

6. A push-chair according to any of the preceding claims and in which the wheel-carrying limbs are spring-biassed towards their folded positions.

7. A push-chair according to any ofthe preceding claims and incorporating means to lockthe frame members in an unfolded state or in a succession of partly-folded states, the locking means comprising a link which joins two adjacent frame members and has a lost-motion connection which allows the frame members to fold and unfold whilst being lockable to hold the members in a select position or positions relative to one another.

8. A push-chair according to Claim 7 and in which the link is a rigid link, fixed to one frame member and slotted to slide back and forth about a pivot on the adjacent member which can be tightened and untightened bya locking knob butwhich is not one of the frame pivots.

9. A push-chair according to any of the preceding claims and with a push-handle which pivots and/or folds flat into the general folded plane ofthe push-chair but with its pivoting and/orfolding movement independent ofthe folding movement ofthe rest ofthe frame.

10. A push-chair according to Claim 9 when appendanttoClaim8and in which the handle isan inverted U-member, each ofwhose opposite ends pivots about a respective one of the locking-knob pivots, and which can be locked by those knobs in selected folded or unfolded positions.

11. A push-chair substantially as described herein with reference to and as illustrated in the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. frames 13 move in towards one another, they push against the toe board 24 and cause it to pivot on its clips 25 aboutthe bar22. The folded push-chair th us assumes the configuration indicated in faint line in the drawings, and if knobs 35,37 are then tightenedthechairis locked in its folded state and cannot inadvertently open. Throughoutthefolding, and any subsequent unfolding, movement, the top ofthe back rest 31, and the front cross bar 18 spanning axis 23, both remain at an unvarying distance from the pivots 32. The canvass seat, although clipped at each opposite side to pivots 32, is not led around orfixed to cross-member 15. Thus the seat material remains unstretched during folding and unfolding of the push-chairframe, whilst conforming automatically to the contours of the seat occupant in use. In the push-chair described and illustrated, the knobs 37 act as safety locks. Once the main pivot knobs 35 have been tightened, the knobs 37 are to some extent redundant; but should the knobs 35 inadvertently become untightened then the tightened knobs 37 and bars 38 prevent the chair frame from folding. In practice, the handle 32 would project somewhat farther than that illustrated, to give a reach comfort able forthe average intended pusherofthe chair. CLAIMS (Filed on 3.8.83)

1. A push-chair in which a foldable frame is supported, in use, byfourground-engaging wheels, and the wheels rotate about respective axes which in use are substantially horizontally and run parallel to oneanotheracrossthechair; theframe members on each side ofthe push-chairform a foldable parallelogram which, when unfolded, enables one pair of parallel members to stand generally upright and define respectively the seat back and the front rail of the chair, whilst the other two parallel members run generally horizontally to define respectively the seat base and the arm rail ofthe chair; and each wheel is carried on a limb which, in use, projects from the base ofthe chair seat and which, when not in use, can fold up against the underside ofthe seat about an axis running along the push-chair.