| WO/2014/063152 | VERTICALLY ADJUSTABLE CASTER WHEEL APPARATUS |
| WO/2003/097380 | A CASTOR MOUNTING ARRANGEMENT FOR A LOAD BEARING VEHICLE |
| US5276941A | 1994-01-11 | |||
| US4491335A | 1985-01-01 | |||
| US4759098A | 1988-07-26 | |||
| US4649596A | 1987-03-17 | |||
| US0314961A | 1885-03-31 | |||
| GB2131289A | 1984-06-20 |
| 1. | A selfleveling mechanism for use with an axle and wheel assembly of a stroller comprising (a) a unitary housing, said housing having first and second chambers, said first chamber having means for vertically adjustably receiving said axle, said second chamber having a releasable locking means in a portion of said second chamber wall; (b) a lightweight spring disposed within said first chamber, said lightweight spring being responsive to the weight of said stroller when unoccupied; (c) a piston disposed within said first chamber in coaxial engagement with said spring, said piston having means for receiving said axle alignable with the adjustable receiving means of said first chamber; and (d) a stroller frame adaptor in which a depending end of a stroller frame is receivable, said adaptor being rotatably mounted within said second chamber, said adaptor including means for operative snapfitting engagement with said releasable locking means, said selfleveling mechanism being responsive to the weight of said unoccupied stroller whereby said mechanism facilitates all wheels of the unoccupied stroller resting on the ground or floor. |
| 2. | The selfleveling mechanism of claim 1 wherein said means for vertically adjustably receiving a wheel axle comprises two vertical diametrically opposed slots, said axle being receivable in each of said slots, said slots allowing adjustment of the housing position relative to said axle to facilitate the response of said mechanism to the weight of said stroller. |
| 3. | The selfleveling mechanism of claim 2 wherein at least one of said opposed slots is provided with an outwardly extending sleeve. |
| 4. | The selfleveling mechanism of claim 2 wherein the means for receiving said axle in said piston comprises a diametrical hole. |
| 5. | The selfleveling mechanism of claim 4 further comprising means for mating engagement of an interior wall of said first chamber with an exterior wall of said piston to prevent rotation of said piston with respect to said first chamber. |
| 6. | The selfleveling mechanism of claim 5 wherein said means for mating engagement comprises a groove on an exterior wall of said piston and a rib on an interior wall of said first chamber, said rib being received within said groove to prevent rotation of said piston with respect to said first chamber. |
| 7. | The selfleveling mechanism of claim 1 wherein said release means comprises a flexible tab depending from said second chamber and a means for. engaging said adaptor means, said flexible tab being in operative relation to said means for engaging said adaptor means. |
| 8. | The selfleving mechanism of claim 7 wherein said means for engaging said adaptor means is a protruding nub on an interior wall of said second chamber and mounted on said flexible tab, and wherein said means on said adaptor for operative engagement with said release means comprises an annular channel on the exterior of said adaptor, said nub being receivable within said channel, whereby said nub is released from said channel by operation of said flexible tab. |
| 9. | The selfleveling mechanism of claim 8 wherein said housing is rotatable about said adaptor to facilitate swiveling of said axle and wheel assembly. |
STROLLER WITH SELF-LEVELING MECHANISM
TECHNICAL FIELD
This invention relates to an improved child's stroller having a self-leveling mechanism for use with an axle and wheel assembly. More particularly, this invention relates to an improved lightweight child's stroller having a self-leveling mechanism for use with an axle and wheel assembly that compensates for minor misalignment of the stroller frame and for minor unevenness of the ground beneath the stroller.
BACKGROUND ART
Collapsible strollers for babies and young children and having rotating casters are well-known. In recent years, lightweight collapsible strollers weighing about 15 pounds or less have become increasingly popular. These lightweight strollers generally comprise a simple steel or aluminum folding frame having four individually mounted casters, and generally do not include any kind of leveling or shock-absorption systems.
These lightweight frames occasionally may be in circumstances such that when the stroller is fully open but unoccupied all four casters are not level with one another in the exact same plane. This may occur, for example, when the strollers are subject to rough handling during shipment, such that the frames are very slightly bent. This may also occur when the stroller is displayed for sale in a retail establishment on an
uneven floor surface. These minor variations in the frame or the floor surface do not affect the operation of the stroller. Yet because all four wheels may not be perfectly level with one another, the stroller may appear less desirable or appealing when displayed in a consumer retail outlet.
It is thus one object of the invention to provide a self-leveling wheel mechanism for a lightweight stroller frame that will compensate for minor variations in the stroller frame or minor unevenness in the ground beneath the stroller.
It is another object of the invention to provide a self-leveling wheel mechanism for a lightweight stroller frame that is of simple, unitary construction and easy to manufacture.
It is yet another object of the invention to provide a self-leveling wheel mechanism for a lightweight stroller frame that is easily attachable to and releasable from the frame.
DISCLOSURE OF THE INVENTION
In accordance with the invention, a self-leveling mechanism for use with a stroller axle and wheel assembly is disclosed comprising a unitary housing having first and second chambers, the first chamber designed to receive a spring and the second chamber designed to receive a depending end of said stroller frame. The first chamber has means for adjustably receiving the axle of the wheel assembly. A piston engages said spring within said first chamber and also
has means for receiving the axle. The axle of the assembly extends through both the receiving means of the piston and the adjustable receiving means of the first chamber. Thus, as gravitational force from the stroller is exerted against the housing and transmitted through the spring to the piston, the adjustable receiving means of the first chamber permits the housing to move vertically relative to the axle and piston in response to said force and any counterforce exerted by the spring. The spring is lightweight such that it partially compresses under the weight of the stroller itself, even when not occupied by a child, thereby ensuring that all wheels of the stroller are in contact with the ground or floor, such as when the stroller is on display in a consumer retail outlet.
The second chamber receives a depending end of the stroller frame which is fitted with an adaptor means. The second chamber includes a release means which mates with an engagement means on the adaptor means. Operation of the release means allows the self-leveling assembly of the instant invention to be easily mounted on or removed from the stroller.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGURE 1 is a perspective view of a self-leveling mechanism of the instant invention assembled with an axle and wheels;
FIGURE 2 is a front elevational view of a self-leveling mechanism of the instant invention;
FIGURE 3 is a side elevational view of a self-leveling mechanism of the instant invention;
FIGURE 4 is a bottom plan view of the housing of a self-leveling mechanism of the instant invention;
FIGURE 5 is a cross-sectional view of an assembled self-leveling mechanism of the instant invention; and
FIGURE 6 is an exploded cross-sectional view of a self-leveling mechanism of the instant invention.
BEST MODE FOR CARRYING OUT THE INVENTION As shown in the Figures, a self-leveling mechanism of the instant invention includes a unitary housing 10 having a first chamber 20 and a second chamber 40 connected by bridge member 12. The two chambers are preferably cylindrical and of circular cross section, with their respective axes oriented parallel to one another. Bridge member 12 can be of solid construction or preferably can comprise two opposed walls 13 and 14 , each said wall joining said first chamber 20 and said second chamber 40 and joined at their top edges by yoke 15. As may be seen, bridge member 12 need not extend the full length of unitary housing 10 as long as it is structurally sufficient to join and stabilize the two chambers of said housing relative to one another.
As most readily seen in Figures 2-4, first chamber 20 has a closed upper end 21 and an open lower end 22. First chamber 20 is provided with means for adjustably receiving an axle of a stroller wheel assembly; said means preferably comprise diametrically opposed slots
23 and 24 located in the walls of first chamber 20 and parallel to the central axis of the cylinder of first chamber 20. Slots 23 and 24 are so positioned in first chamber 20 as to adjustably receive the axle of the wheel assembly as will be described herein. Slots 23 and 24 are preferably provided with outwardly extending sleeves 123 and 124 to provide added stability to the self-leveling mechanism when assembled with an axle and wheels.
Lightweight spring 25 is disposed within first chamber 20. Spring 25 is of such size and strength as to offer resistance to the weight of the stroller itself, but not to the weight of a child in the stroller, nor will the spring provide shock absorbance. A spring suitable for use in the instant invention may be of about 0.035 size wire, have about 10-1/2 coils, measure about 1.220 inches from end to end when under zero compression, and have a total compression weight at full compression of about 2.1 lbs.
When disposed in first chamber 20, spring 25 is engaged at its upper end by closed upper end 21 of first chamber 20 and at its lower end by piston 26. Piston 26 is substantially cylindrical, and has an axial projection 27, the outer circumference of which defines an annular shoulder 28 in the body of piston 26. When piston 26 engages spring 25, and the lower end of spring 25 abuts annular sholder 28. Piston 26 is further provided with means for receiving the axle of the wheel assembly, which means preferably comprises diametrical hole 29. Hole 29 is so sized and shaped so as to receive the axle of the stroller wheel assembly,
and is alignable with slots 23 and 24. Piston 26 is also provided on its exterior wall with a linear groove 31 that runs parallel to the piston axis. Groove 31 is adapted to receive rib 32 on the interior wall of first chamber 20. The engagement of rib 32 within groove 31 serves to prevent any undesirable rotation of piston 26 within first chamber 20.
Second chamber 40 is substantially cylindrical and is open at both lower end 41 and upper end 42. Flexible tab 43 extends downwardly from lower end 41, and is preferably located between opposed walls 13 and 14 of bridge member 12. Flexible tab 43 may be deformed in a direction away from the central axis of second chamber 40. A protruding nub 44 is located on the interior wall of second chamber 40, and adjacent to and in operative relation with flexible tab 41. An adaptor 50 is designed to fit on a lower end of a stroller frame, and to be attached thereto with a screw or other fastening means through screw hole 56 which aligns with a corresponding hole on the stroller frame, not shown. Adaptor 50 fits within second chamber 40 in rotational engagement, such that the wheel assembly of the instant invention can swivel through a full 360° range of motion for easy maneuvering of the stroller. Adaptor 50 is provided on its upper end with a collar 51 which rests on the upper end 42 of second chamber 40. Adaptor 50 is also provided on its lower end with two annular ridges 52 and 53 which together define a channel 55. When adaptor 50 is fitted into second chamber 40, nub 44 is held in snap-fitting relation within channel 55. When tab 41 is flexed away from the central axis of second chamber 40, then nub 44 is
pulled out of channel 55, whereby the entire housing 10 is releasable from adaptor 50 and the stroller frame.
When the self-leveling mechanism of the instant invention is fully assembled with axle and wheels, axle 60 passes through first wheel 62, first bearing 64, first slot 23 of first chamber 20, hole 29 of piston 26, second slot 24 of first chamber 20, through second bearing 66, and second wheel 68.
In a preferred mode of operation, two self-leveling mechanisms of the instant invention are mounted on the front wheel assemblies of the frame of a lightweight collapsible stroller. As is known, these lightweight strollers may experience rough handling during shipping which may cause the frame to be slightly out of alignment. When the stroller is removed from its packing crate and set up for display in a store, any misalignment of the frame may cause one of the four wheels to be out of the plane of the other three wheels, so that all four wheels do not touch the floor. Even if the stroller frame is undamaged, an uneven floor surface might make it appear that the stroller frame is misaligned if all four wheels do not touch the floor. When the self-leveling mechanisms of the instant invention are used, the weight of the stroller exerts a downward force through adaptor 50 on second chamber 40 of housing unit 10. This downward force is transmitted through bridge 12 to first chamber 20, which is urged downwardly against spring 25. Lightweight spring 25 yields to the relatively small downward force of the lightweight stroller, so that housing 10 may move vertically relative to axle 60,
whereby the entire stroller frame is brought into proper alignment and all four wheels will be in contact with the floor, regardless of any minor misalignment of the frame structure or unevenness of the floor surface.
A self-leveling mechanism has been disclosed which is simple, lightweight, easy to manufacture and assemble and effectively corrects for minor misalignment in the frame of a lightweight stroller or unevenness of the floor or ground, when the stroller is unoccupied. It is to be understood that the present disclosure is made by way of example only and that certain changes may be made without departing from the spirit and scope of the invention as hereinafter claimed.