GB2425287A

GB2425287A - Wheel converter for small diameter solid wheels to large diameter wheels with pneumatic tyres

Info

Publication number: GB2425287A
Application number: GB0508081A
Authority: GB
Inventors: Cameron Andrews
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-04-21
Filing date: 2005-04-21
Publication date: 2006-10-25
Also published as: GB0508081D0

Abstract

Large-diameter, all terrain wheels with pneumatic tyres 1 are fixed to the solid small-diameter wheels 2 of a non-driven pushchair via the attached wheel casings 5 to enable stable off-road use. Both wheels of the double wheel arrangement common to pushchairs sit in the wheel casings and are fixed securely by straps 9. A rigid support 6 between the casings strengthens the device. Working together, the casings and support encourage the dispersion of downward pressure through the device, providing added stability and improving the pushchair's all-terrain, all-weather capabilities. The rigid support between the casings may have a mechanism 7 to adjust its length to enable secure use of the device on different models of pushchair. The fixing mechanisms 3 in the device may be detachable to enable easy assembly / disassembly and storage.

Description

Wheel converter, incorporating stabilising features, for small-diameter

solid wheels to large- diameter wheels with pneumatic tyres This invention relates to a large-diameter, wheeled device with pneumatic tyres that fixes to the small- diameter, solid, double wheels of a non-driven pushchair I perambulator to provide stable all-terrain, all-weather capabilities.

When using a pushchair with a double set of small-diameter solid wheels at each wheel position, rough terrain and bad weather conditions such as snow can make manoeuvring the vehicle difficult. If two sets of detachable, large-diameter, off-road wheels are attached to the existing small-diameter wheels (one set for the front wheels and one set for the rear wheels), this would lift the pushchair higher from the ground and provide suitable grip and tyre pressure to manage the rough ground.

Furthermore, many pushchairs with small-wheel diameters suffer from weak fixings between the wheels and the frame of the pushchair, most notably on products offering swivel' wheels. As off-road activities are likely to result in greater pressure exerted on the pushchair than during on-road activities, the joint fixing the small-diameter wheels to the chassis may be misshapen, impeding the progress of the vehicle and potentially causing it damage.

To overcome this problem, this invention includes two specific features: i) a casing in which each set of the pushchair's double wheels will sit, thereby dispersing downward pressure through both wheels, rather than just the outside wheel.

ii) a rigid support* (extendable or fixed) attached to the casings in which the small-diameter wheels will sit. Such a fixing will provide a support between the pushchair's wheels, further dispersing the downward pressure. For pushchairs with swivel' wheels, the support fixing will also limit the negative effect of the wheels being pushed in opposite directions by rough ground. These factors will give the pushchair greater stability and will improve its off-road capabilities. The (extendable) support is fitted to the wheel casing with a permanent fixing or a push button snap lock** that fixes securely to an attachment point moulded to the wheel casing.

* N.B: For the purposes of this illustration an extendable rigid support, namely an extendable pole, will be used hereon. The extendable pole allows the invention to be used across a broad range of pushchairs, accommodating the fact that many different designs of pushchair have different wheel spacings. However, in all instances where the extendable pole is used, this can be substituted for a fixed pole of appropriate length relative to a particular make I model of pushchair. This may reduce manufacturing costs.

** N.B: The push button snap lock method of attachment, which gives the invention's user the ability to store the invention in pieces rather than as a single unit, can be substituted for a rivet / nut and bolt or other permanent fixing mechanism in all instances where it is used. For the purposes of this illustration, however, the push button snap lock will be used hereon.

The invention also addresses the problem of creating a higher centre of gravity in the pushchair that arises when fitting the larger off-road wheels. With the off-road wheels attached to the small-wheel casings and so protruding outside the original wheel spacing of the small-diameter wheels, a wider wheel spacing is created. This then compensates for the pushchair's higher centre of gravity and means that the pushchair will remain stable while off-road.

To ensure that the small-diameter wheels are fixed securely in their casings a strap, incorporating properties that grip the surface to which it is attached, is fitted over the small-diameter wheels. The adjustable strap affixes directly to the rear of the wheel casing and via a locking mechanism to the front of the casing thus impeding the rotational movement of the small-diameter wheels and improving the stability of the device. The locking mechanism for straps can constitute either a fixed fastener such as a buckle or a separable fastener, which for the purposes of this illustration will be used hereon.

When using the invention, any available wheel lock on the pushchair should be engaged at all times to ensure that the small-diameter wheels remain fixed in place in the wheel casings. This provides added stability assisting in the impediment of the rotational movement of the smalldiameter within the wheel casings when the pushchair is in motion.

To ensure safety, this invention also includes two separate braking mechanisms, attached to the rear off-road wheels, for use when the pushchair to which the off-road wheels are attached is stationary.

The invention can also be applied to double pushchairs (i.e. those that seat two infants side-by-side).

Given the differing types of double pushchairs available in the commercial market the invention provides ways to accommodate two dominant designs. They are: i) a double pushchair which has two seats side-by-side and which rests on two sets of wheels, front and back.

ii) a double pushchair that is similar to that of the first, but which includes a third set of wheels, front and back. These are spaced inbetween the standard pair, beneath the centre point of the pushchair where the two seats are joined.

To address the first design (outlined in feature (i), above), the invention can be adapted to include either: a) a double extendable pole (in that it has two extendable lengths of pole and two extending mechanisms) that extends to such a length to accommodate the distance between a double pushchair's wheels.

b) a single extendable pole of double length (i.e. of sufficient length to bridge the gap using only one extending mechanism).

For the second design (outlined in feature (ii), above), a third casing unit is used. In this instance, the right-hand off-road wheel attaches to the right-hand casing in which the right-hand small-diameter wheels sit. A single extendable pole then attaches to this unit, which extends to a second casing enclosing the middle set of small-diameter wheels. This then attaches to another single extendable pole which attaches to the left-hand casing in which the left-hand set of small-diameter wheels sit. On the outside of this set of wheels, the left-hand off-road wheel is attached.

The invention will now be described solely by way of example and with reference to the accompanying drawings in which: Figure 1 shows a set of off-road wheels attached to a single-seater pushchair's small-diameter wheels, using two wheel casings and a single-length extendable pole.

Figure 2 shows the individual casing unit in which the pushchair wheels sit.

Figure 3 shows an individual casing unit with straps and locking mechanisms attached.

Figure 4 shows a single extendable pole with locking mechanism and push button snap lock.

Figure 5 shows an all terrain wheel and the fixing mechanism with which to attach it to the wheel casing.

Figure 6 shows the mechanism used to fix the all terrain wheel to the casing unit.

Figure 7 shows detail of the mechanism that is used to secure the all terrain wheel in position.

Figure 8 shows the front elevation of the same detail shown in Figure 7.

Figure 9 shows detail of the dust cover that is used in conjunction with the mechanism that is used to secure the all terrain wheel in position.

Figure 10 shows the braking mechanism for the rear set of off-road wheels.

Figure 11 shows the braking mechanism for the rear set of off-road wheels as it appears in the mechanics of the invention.

Figures 12 and 13 show the detail of the two parts of the breaking mechanism in profile.

Figures 14, 15 and 16 show an alternative to the wheel securing mechanism and means of attachment for the breaking mechanism and dust cover.

Figure 17 shows a set of off-road wheels attached to a two-seater pushchair's small-diameter wheels, using two wheel casings and a double extendable pole with two extending mechanisms.

Figure 18 shows a set of off-road wheels attached to a two-seater pushchair's small-diameter wheels, using three wheel casings and two single-length extendable poles.

In figure 1, an off-road wheel 1 is attached via a fixing mechanism 18 to a single-seater pushchair's small-diameter wheels 2, via the locking mechanism 3 on the attachment point 4 of the wheel casing 5. A single-length extendable pole 6, incorporating a locking mechanism 7 to provide rigidity, attaches to a second wheel casing and off-road wheel 8. A strap with grip 9 is fixed over the small-diameter wheel and attached via a locking mechanism 10 to the wheel casing. The locking mechanism itself attaches to the wheel casing via an attachment piece for the strap 11, which is moulded to the casing.

12 shows part of the frame of the pushchair where it attaches to the small diameter wheels.

Figure 2 shows a moulded wheel casing 5, detailing the locking mechanism 3 to which the wheel fixing mechanism or extension pole attaches to the attachment point 4 of the wheel casing unit by use of a push button snap lock on the pole I wheel fixing mechanism. The pole or wheel fixing mechanism is locked in place by the push button snapping into place and protruding through the holes in the attachment point.

Also shown as moulded to the casing is the attachment piece 11 to which the locking mechanism for straps is attached. The strap with grip that is fixed over the small-diameter wheel is fixed to the attachment piece 13.

In Figure 3 the wheel casing 5 is shown with attachment pieces 11 and 13 shown with straps 9 sewn into position. The straps are shown with the two parts of a separable fastener 14 not joined. A buckle, or other fixed fastener, may be used as a substitute locking mechanism for the straps.

Figure 4 shows the detail of a single-length extendable pole 6, with locking mechanism 7 that is turned to fasten the inner 15 and outer 16 poles of the structure. A push button snap lock 17, which retracts into the hollow of the pole, is also evidenced. This is used to fasten the pole to the attachment point of the wheel casing.

To ensure a snug and therefore stable fit between the thinner, inner length of pole 15 and the attachment point of the wheel casing, the end of pole 15 may be widened to that of the diameter of pole 16 (which is the same as that of the locking mechanism) or the end of pole 15 may be fitted with an outer band which will also enlarge its diameter to fit that of the attachment point.

Figure 5 shows an all terrain wheel and the fixing mechanism 18 that is used to attach it to the attachment point of the wheel casing. Fixing mechanism 18 constitutes a length of pole of the same diameter to that of pole 16 with a push button snap lock I 7a that retracts into the hollow of the pole and which fastens the pole to the attachment point of the wheel casing. Once fixed to the attachment point of the wheel casing, the wheel (which incorporates a centre piece constituting a hole of the diameter of the pole) is fitted over the pole and is held in place between the attachment point of the wheel casing on the inside and a wheel securing mechanism 19 on the outside. A dust cover 20, which stops dirt from entering the inside of the hollow pole, is also shown (N.B: the dust cover is only used on the front set of wheels. A breaking mechanism substitutes the dust cover on the rear set of wheels - see Figure 10).

Figure 6 shows detail of fixing mechanism 18. A square hole 35 is cut on either side of the length of pole in to which protruding parts on the inside surface of the wheel securing mechanism (which fits over the end of the pole) are lodged, thus securing the wheel.

Figure 7 shows the wheel securing mechanism 19, which is a moulded unit, cylindrical in shape and which has a hole through its middle, enabling it to be fitted over the length of pole that is part of the fixing mechanism.

Figure 8 shows the wheel securing mechanism 19 in its front elevation, detailing the protruding parts 21 on its inside surface. These are able to be flattened against the length of pole as the wheel securing mechanism is slid into position until passing over the square holes cut on either side of pole at which point they will naturally protrude thus fixing the wheel securing mechanism in place.

Figure 9 shows detail of the dust cover 20. This moulded unit is fixed into place after the wheel securing mechanism has been slid onto the pole, but before the protruding parts of the wheel securing mechanism have been engaged. The dust cover is fitted by pushing moulded part 36 into the inside of the pole until moulded part 22 is flush with the end of the pole and wheel securing mechanism. Once the dust cover has been inserted into place, the protruding parts of the wheel securing mechanism are engaged with the holes in the wheel fixing mechanism. The dust cover is then held firmly in place by the protruding parts of the wheel securing mechanism, which engage with moulded part 36.

Figure 10 shows the braking mechanism 23 for the rear set of off-road wheels, which is attached in place of the dust cover (see Figure 11). The breaking mechanism constitutes a moulded unit based on the design of the dust cover, with the method of attachment identical to that of the dust cover. Part 24 is a fixed axis that is moulded to the mechanism 29 that enables the breaking mechanism to be held securely in position in the same manner as the dust cover for the front wheels. Part 25 is a separate moulded unit that can rotate beside part 24 when connected with a nut and bolt at point 26.

Figure 11 shows the braking mechanism 23 for the rear set of off-road wheels as it appears in the mechanics of the invention. The mechanism works by the operator pushing up at point 27 using their foot or hand. The mechanism then swivels on the fixed axis 24 to ensure that point 28 is fixed between the spokes of the wheel to disable their turning. A breaking mechanism is fitted to each of the rear wheels. The wheel securing mechanisml9, wheel casing 5 and attachment point of the wheel casing 4 are also shown.

Figure 12 shows the detail of part 25 in profile; the rotational piece of what is a two-part, moulded braking mechanism.

Figure 13 shows the detail of part 24 in profile; the fixed axis of what is a two-part, moulded braking mechanism. 29 is the attachment piece of part 24. 30 protrudes around the cylindrical edge of the attachment piece as with part 22 on the dust cover (see Figure 9) and when fixed is flush with the end of the pole and wheel securing mechanism (see Figure 11).

The components shown in Figures 12 and 13 fit together as follows. Part 24 fits to part 25 at points 26. The movement of part 25 is limited when attached to 24 due to protruding piece 31, which clicks into the hollows 32 over the central barrier 33.

Figure 14 shows fixed axis 24 of the breaking mechanism with an integrated wheel securing mechanism 36 (as an alternative to wheel securing mechanism 19 shown in Figures 7 and 8) and an integrated attachment piece 37 (as an alternative to attachment piece 29 shown in Figure 13).

Attachment piece 37 includes a screw thread.

Figure 15 shows detail of the dust cover (as an alternative to dust cover 20 shown in Figure 9). A moulded unit, it incorporates the integrated wheel securing mechanism 36 and the integrated attachment piece 37.

Figure 16 shows the length of pole that is part of the fixing mechanism 18 (shown in Figure 6) that attaches the wheel to the wheel casing as shown in Figure 6. The unit is adapted so that instead of attachment holes 35 (shown in Figure 6), there is a screw thread 38 providing a means with which to attach the wheel securing mechanism / dust cover / breaking mechanism 39.

The alternative system shown in Figures 14, 15 and 16 allow the user to detach the wheels for cleaning or repair. To save manufacturing costs, an alternative, similar system can also be used whereby the screw thread on part 37 can be a smooth unit that can be attached using a permanent fixing means to the length of pole that is part of the fixing mechanism that attaches the wheel to the wheel casing.

Figure 17 shows a set of off-road wheels attached to a two-seater pushchair's small-diameter wheels, using two wheel casings 5 and a double extendable pole 34 with two extending mechanisms. N.B: the double extendable pole with two extending mechanisms can be substituted for a double-length, single extendable pole with a single extending mechanism.

Figure 18 shows a set of off-road wheels attached to a two-seater pushchair's small-diameter wheels, using three wheel casings 5 and two single-length extendable poles 6.

Claims

Claims 1) A large diameter-wheeled device with pneumatic tyres that fixes

to the front or rear solid wheels of a small-wheeled, non-driven pushchair, the large diameter wheels to be fitted to the pushchair via casing units in which each set of the pushchair's small-diameter double wheels will sit and be secured by a fixing mechanism.
2) A large diameter-wheeled device with pneumatic tyres that fixes to the front or rear solid wheels of a small-wheeled, non-driven pushchair according to claim 1 in which the small- diameter wheel casing units and fixing mechanism hold both wheels of the double-wheel arrangement securely, inhibiting the rotational movement of the small-diameter wheels and supporting the joint between the small- diameter wheels and the pushchair's frame, and thus providing rigidity to the structure.
3) A large diameter-wheeled device with pneumatic tyres that fixes to the front or rear solid wheels of a small-wheeled, non-driven pushchair according to claim 1, in which the casing units are fixed together securely by a rigid support, further strengthening the structure and rigidity of the device.
4) A large diameter-wheeled device with pneumatic tyres that fixes to the front or rear solid wheels of a small-wheeled, non-driven pushchair according to claim 3 in which the rigid support between the casing units can be adjustable to fit the device securely to different models of pushchair.
5) A large diameter-wheeled device with pneumatic tyres that fixes to the front or rear solid wheels of a small-wheeled, non-driven pushchair according to claim 3 in which the fixing mechanism used to attach the rigid support to the casing units can be detachable to enable easy assembly / disassembly.
6) A large diameter-wheeled device with pneumatic tyres that fixes to the front or rear solid wheels of a small-wheeled, non-driven pushchair according to claim 3 in which additional casing units and rigid supports can be used to extend the device for use on pushchairs that seat more than one infant.
7) A large diameter-wheeled device with pneumatic tyres that fixes to the front or rear solid wheels of a small-wheeled, non-driven pushchair according to claim I in which the attachment means used to fix the largediameter wheels to the casing unit can be detachable to enable easy assembly / disassembly.
8) A large diameter-wheeled device with pneumatic tyres that fixes to the rear solid wheels of a small-wheeled, non-driven pushchair according to claim 1, whereby the mechanism that secures the large diameter wheel on the inside facing part of the device is the outside edge of the casing unit at the point where the length of pole that the wheel rotates around is fixed.
9) A large diameter-wheeled device with pneumatic tyres that fixes to the rear solid wheels of a small-wheeled, non-driven pushchair according to claim 1, whereby the mechanism that secures the large diameter wheel on the outside facing part of the device is fixed in place and integrated with the dust cover / breaking mechanism, either as a single moulded unit or as an arrangement of interlocking parts.
10) A large diameter-wheeled device with pneumatic tyres that fixes to the front or rear solid wheels of a small-wheeled, non-driven pushchair according to claim 9 in which the application of the breaking mechanism in place of the dust cover provides breaking capabilities and distinguishes the device as that which fits to the rear set of the pushchairs wheels.
11) A large diameter-wheeled device with pneumatic tyres that fixes to the rear solid wheels of a small-wheeled, non-driven pushchair as herein described above and illustrated in the accompanying drawings.