GB2601127A

GB2601127A - Ball-projection machine

Info

Publication number: GB2601127A
Application number: GB2018116.0A
Authority: GB
Inventors: Charles Pryor Henry
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-11-18
Filing date: 2020-11-18
Publication date: 2022-05-25
Also published as: GB202018116D0

Abstract

A three-wheel cricket bowling machine 10 comprises first second and third counter-rotating drive wheels 1A-1C which are independently driven 2A-2C with a speed differential. The first drive wheel 1A is angularly offsettable about a vertical axis (X) to achieve the spin required to project a cricket ball 3 with a full range of cricket deliveries. The drive wheels and associated mountings are carried on a tiltable and turnable rectangular frame (F). The parallel lower drive wheels 1B, 1C are tapered, enabling their axes (A3) and associated motors 2B, 2C to be mounted vertically, thereby lowering the centre of gravity.

Description

Ball-projection machine The present invention concerns a three-wheel ball-projection machine, and is particularly but not exclusively concerned with a bowling machine for use in cricket.

By a three-wheel ball-projecting machine is meant a ball-projecting machine in which the ball is impelled by three powered wheels.

Bowling machines are commercially available, one of the best known being the Merlyn (RTM) bowling machines as disclosed in GB 2,293,979B, in GB 2,430,892A, in GB 2,481,140B, in GB 2,451,904B and in GB 2,553,610B (all in the name of the present applicant). The GB '979B machine has four counter-rotating wheels which are spaced apart and disposed at 90° intervals with their axes lying in a common plane transverse to the axis of projection of the ball. One pair of opposed counter-rotating wheels can be used to impart a spin about one axis orthogonal to the axis of projection and the other pair of diametrically opposed counter-rotating wheels can be used to apply spin about the other axis orthogonal to the axis of projection, in each case by varying the relative speeds of the opposed wheels.

Three of the more recent machines (of GB.892A, GB 140B and GB 1904B) all have two opposed drive wheels and have the advantage of being significantly lighter than the four-wheeled bowling machine of GB '979B, since they require only two electric motors rather than four and the associated frame and lifting gear are also correspondingly lighter.

In GB 2,430,892A the opposed drive wheels are mounted on a sub-frame which is rotatable about the axis of projection of the ball in order to vary the orientation of the axis of the spin applied to the ball and hence achieve a range of standard cricket deliveries.

In GB 2,553,610B there are three counter-rotating drive wheels, including an uppermost drive wheel whose axis of rotation is angularly offsettable so as to impart a spin to a cricket ball about its axis of projection, the two other drive wheels having axes of rotation fixed in a substantially coplanar configuration and being driven with a speed differential so as impart spin orthogonal to the axis of projection. The axis of rotation of the uppermost drive wheel is offsettable out of the common plane of the axes of the two other drive wheels. The mid-planes of the other drive wheels subtend an angle of less than 120°, eg 50° to 110° US 4,442,823 discloses a three-wheel ball projecting machine for use in baseball. It includes three drive wheels spaced at 120° intervals and each angularly offsettable about an axis orthogonal to its axis of rotation to impart spin to the ball about the axis of projection. There is no disclosure of cricket or cricket deliveries in this patent.

US 2013/087131 (Paulson eta!) also discloses in one embodiment a three-wheel ball-projection machine for throwing baseballs, softballs, tennis balls and the like. The drive wheels are fixed in a common plane with their drive axes at 120° intervals but in a variant, it is taught that the orientation of one or more of the drive wheels may be adjustable. No further details of the adjustment are given.

All the above prior art machines utilise drive wheels with cylindrical drive surfaces.

The present invention provides a three-wheel ball-projecting machine comprising an array of first, second and third counter-rotating drive wheels having spaced-apart peripheral surfaces which cooperatively engage and project a ball and wherein the axis of rotation of the first drive wheel is angularly offsettable so as to impart a spin to the ball about its axis of projection and wherein the second and third drive wheels are tapered, the drive wheels each being coupled to drive means which in use can drive at least two of them with a speed differential to impart a spin orthogonal to the axis of projection.

This arrangement can be made with a lower centre of gravity than that of GB 2553610B because the taper of the second and third drive wheels allows their drive means (eg directly-coupled electric motors) to be positioned immediately below them.

This also minimises the height of the arrangement. In this manner the stability of the apparatus and hence reproducibility of deliveries can be improved.

Preferably the axes of rotation of the second and third drive wheels are substantially parallel. This enables the height of the second and third drive wheels and their associated drive means (eg directly coupled electric motors) to be minimised.

Preferably the axis of rotation of the first drive wheel is angularly offsettable out of a common plane of the axes of rotation of the second and third drive wheels.

The second and third drive wheels may have a tapered profile. The second and third drive wheels may be tapered relative to their radial plane, such that the drive wheels may have a frusto-conical shape, for example. A first surface perpendicular to the axis of rotation may have a smaller radius than that of a second surface perpendicular to the axis of rotation.

Preferably the angle of taper of the second and third drive wheels relative to their radial plane is in the range 40° to 80°, more preferably 45° to 75°, most preferably 45° to 70° Preferably said first drive wheel is disposed above said second and third drive wheels.

The drive wheels may be fixable at a plurality of positions such that they can sufficiently grip balls of different sizes. At least one of the drive wheels may biased towards the other drive wheels by spring means so as to accommodate balls of different sizes in the gap between said peripheral surfaces. The two bottom drive wheels may be fixable in position, thereby fixing the gap between the drive wheels.

Preferably the three-wheel ball-projecting machine is a cricket bowling machine in which the spacing between said opposed peripheral surfaces is such that they can grip a cricket ball, said machine having first means for varying the angular offset of said first drive wheel and second means for varying a speed differential between at least two of the first, second and third drive wheels, said first and second means having settings which in combination correspond to standard cricket deliveries.

Preferably respective setting combinations correspond to at least two, if not all of the following cricket deliveries: i) straight ii) in swing iii) away swing iv) leg break v) off break vi) leg cutter vii) off cutter Preferably respective setting combinations correspond to at least one straight or bouncer or yorker delivery, at least one in swing or away swing delivery, and at least one off break or leg break delivery.

Preferably respective setting combinations correspond to at least one straight delivery, at least one in swing or away swing delivery, and at least one off cutter or leg cutter delivery, or correspond to at least one straight, at least one off break or leg break delivery, and at least one off cutter or leg cutter delivery.

Preferably said axis of rotation of the first drive wheel is angularly offsettable about an axis which lies in a substantially vertical plane.

Preferably the plane of rotation of said first drive wheel is settable to at least three orientations on each side of a central orientation corresponding to a straight delivery.

A straight delivery can include a bouncer or yorker delivery, for example.

Preferably the angle between adjacent settable orientations of said plane of rotation is in the range 6 to 14 degrees, more preferably in the range 8 to 12 degrees, most preferably in the range 9 to II degrees.

In a preferred embodiment the three-wheel ball-projecting machine comprises a frame carrying said drive-wheels and drive means, a sub-frame supporting said frame at one end of the sub-frame, and a pivotal support supporting the sub-frame at an opposite end of the sub-frame, the sub-frame being rotatable about a substantially horizontal axis to allow the frame and associated drive wheels and drive means to be lowered to reconfigure the machine from a deployed configuration to a transport configuration.

Preferably said frame is oriented transversely when the ball-projecting machine is in a deployed configuration and can be rotated to a longitudinal orientation before rotating the sub-frame to lower the drive wheels and drive means and thereby reconfigure the machine to the transport configuration in which the frame is oriented longitudinally.

Further preferred features are defined in the dependent claims Reference is directed to GB 2,430,892A (noted above) which discloses certain electronic control features and feed mechanisms which can optionally be utilized in the ball-projecting machine of the present invention. The disclosures of the above electronic control features and feed mechanisms in the above patent application are hereby incorporated by reference.

However the preferred embodiment is hand operated (i.e. the angles of the drive wheels are selected manually), only the drive wheel speeds being determined electronically. This preferred apparatus can preferably be tilted and turned manually and is not programmable.

The preferred embodiment of the present invention is shown in Figures Ito 10 of the accompanying drawings, wherein: Figure 1 is a front elevation of the movable frame assembly of a three-wheel cricket bowling machine in accordance with the present invention, Figure 2 is a diagrammatic front elevation of the drive wheel arrangement in Figure 1 with the upper drive wheel arranged to impart a spin (top spin) to the ball about a horizontal lateral axis, Figure 3 is a vector diagram in plan view showing the relationship between the radial wheel velocities needed to impart a spin about the upright axis X; Figure 4 is a vector diagram in plan view showing the relationship between the angle of the upper wheel and the wheel velocities needed to impart a spin about the axis of projection; Figure 5 is a diagrammatic front elevation of a variant of the drive wheel arrangement of Figure 1 with the upper drive wheel arranged to impart a spin to the ball about the axis of projection; Figure 6 is a diagrammatic front elevation of a further variant of the drive wheel arrangement of Figure 1 with the upper drive wheel arranged to impart a spin (swing delivery) to the ball about an upright axis; Figure 7 is a schematic side elevation of the cricket-bowling machine shown in Figure 1, with the delivery arrangement shown schematically in cross section; Figure 8 is a top plan view showing the range of angular orientations of the upper drive wheel; Figure 9 is a diagrammatic representation of the cricket ball trajectory in plan view (or in elevation in Figures 4d) and e)) for various standard cricket deliveries achievable by the above bowling machine, and Figure 10 is a side elevation of a three-wheel bowling machine in accordance with the present invention and incorporating the movable frame assembly of Figure 1.

Referring to Figure 1, a movable frame assembly 10 is mounted on a transverse supporting bar 6 and comprises a yoke Y rotatable about a vertical axis X. A generally rectangular frame F is mounted at the mid-point of its long sides for rotation about a horizontal tilt axis A2 on yoke Y and in the mid-point of its upper side carries a pivot 7 on which is mounted a generally L-shaped mounting bracket B which is rotatable about an upright axis which is coincident with axis X when the frame F is vertical as shown. Axis Al lies in the mid plane of frame F and is orthogonal to the axis of projection of the ball 3 and to tilt axis A2 It will be noted that axis X is laterally offset from the centre of supporting bar 6, for reasons explained below in relation to Figure 10.

Bracket B carries a variable speed electric drive motor 2A and an upper (first) cylindrical drive wheel IA is mounted on the drive shaft of this drive motor. A supporting bracket 4 is secured between opposite upright sides of frame F beneath axis A2 and carries two lower (second and third) variable speed electric drive motors 2B and 2C which drive respective lower drive wheels 1B and IC mounted on their drive shafts.

As shown, each drive wheel 1B and IC is tapered inwardly towards the first drive wheel IA to form (typically somewhat rounded) frusto-conical drive surfaces.

In use, the cylindrical drive surface of upper drive wheel lA co-operates with the frusto-conical drive surfaces of the lower drive wheels 1B and 1C to engage and project a cricket ball 3.

The axes of rotation A3 of drive wheels 1B and 1C are substantially coplanar and the axis of rotation of pivot 7 lies in or close to their common plane. Thus, axis Al is angularly offsettable out of this common plane.

The angle of taper A (i.e. the angle subtended by the drive surface of drive-wheel 1B or IC and the radial plane of that drive wheel in an axial plane defined by axis A3) is 70° in this embodiment.

As explained below with reference to Figure 5, a larger value of A would favour configurations for applying spin about the axis of projection (for leg break, off break, leg cutter and off cutter deliveries). As explained below with reference to Figure 6, a smaller value of A would favour the configurations for applying spin about an upright axis (for in swing and away swing deliveries).

Generally, as noted above, the angle A is in the range 40° to 80°, more preferably 45° to 75° and most preferably 45 to 70 ° In a given bowling machine, angle A is normally fixed but in principle could be varied by providing two or more sets of lower drive wheels with different angles of taper A.

S

The drive wheels define a central gap between them corresponding to the diameter of a cricket ball. The diameter of the central gap is suitably 54mm (2.125") compared to the 70mm diameter (2.75") diameter of a cricket ball. A cricket ball 3 is shown engaged by the peripheral regions of the drive wheels, which are driven to counter rotate in the sense indicated by the arrows to project a ball along an axis of projection extending out of the plane of the drawing. Pivot 7 exerts a downward pressure on the cricket ball to ensure it is gripped by all three drive wheels. The pivot 7 (which is preferably adjustable by a screw (not shown) to vary the distance between axis Al and the intersection of planes p2 which are orthogonal to the frusto-conical drive surfaces of the lower drive wheels) has sufficient downward travel, (eg lmm) to accommodate cricket balls of slightly different diameter, eg a 64mm diameter cricket ball. The cricket ball is resiliently engaged between the opposed peripheral regions of the drive wheels.

It will be appreciated that in the configuration shown in Figure 1, if the peripheral speeds a, b, c of the respective drive wheels IA, 1B and 1C are the same, the ball will be projected without spin along an axis of projection which is orthogonal to the plane of the drawing, whereas if (say) the peripheral speed a of the first (upper) drive wheel lA is greater than the speeds b and c of the second and third (lower) drive wheels 1B and IC, then top spin will be imparted to the ball 3. If the peripheral speed a of the upper drive wheel 1 A is lower than peripheral speeds b and c, then back spin will be imparted.

In general, by varying the speeds of the wheels 1A, 1B and 1C, and the orientation about axis X of wheel 1A, a wide range of spins about the horizontal axis orthogonal to the axis of projection, about the upright axis X, and about the axis of projection can be achieved, all as used in cricket. This is illustrated in Figures 2 to 4.

Referring to Figure 2, if the upper drive wheel IA has a peripheral velocity a which is greater than the peripheral velocities b and c of the lower drive wheels 1B and IC, then a down spin will be imparted to the ball 3 about the horizontal axis orthogonal to the axis of projection, as indicated by arrow S. If the peripheral velocity a is less than the peripheral velocities hand c of the lower drive wheels 1B and 1C, then an up spin will be imparted to the ball 3.

Referring to Figure 3, if there is progressive increase in peripheral velocities c, a and b as shown, then this is equivalent to an anticlockwise rotation (spin S) as shown, proportional to the difference b -c, superimposed on a ball velocity a The reverse (clockwise) spin can be imparted by a progressive increase in the opposite sense.

Referring to Figure 4, if the upper wheel is swung to an angle and rotated with a peripheral velocity a such that its forward component a2 = b = c, then the transverse component al will impart a clockwise spin S (as seen looking from the bowling end to the batsman) about the axis of projection of the ball 3 Referring to Figure 5, a variant is shown in front elevation (as seen by the batsman) in which the angle between the opposed regions of the respective frusto-conical drive surfaces of the lower drive wheels 1B and 1C is reduced, corresponding to a larger angle A. When the axis of the upper drive wheel IA is moved anticlockwise to the orientation shown, the rotation of this drive wheel urges the cricket ball 3 against drive wheel IC and away from drive wheel 1B. Accordingly the main driving contact to the ball is applied by drive wheels IA and IC and the effect is to apply a spin S about the axis of projection as shown. The reverse spin can be applied by moving the axis of the upper drive wheel IA to a clockwise setting.

Conversely, in the variant shown in Figure 6 in which the angle between the opposed regions of the respective frusto-conical drive surfaces of the lower drive wheels 1B and IC is larger (A is smaller), the ball 3 is held firmly in contact with both the lower drive wheels irrespective of the orientation of the axis of the upper drive wheel 1A. If the speed of drive wheel 1B is greater than that of drive wheel IC (as shown by the vector arrows) a spin is applied to the ball about an upright axis (as indicated by broad arrow SW) which results in a swing delivery. The reverse configuration, with the speed of drive wheel IA greater than that of drive wheel 1B, results in a swing delivery in the opposite direction.

Referring to Figure 7, it will be seen that the frame F is coupled to the yoke Y by an adjustable linkage 5 to enable the angle of elevation of the axis of projection (shown as a broad left-pointing arrow in Figure 7) to be varied. Figure 7 also shows an inclined guide frame C carried by frame F on its rear side and extending between the drive wheels 1A, 1B and W. Guide frame C includes a lower central rail and two side rails. Cricket balls, eg ball 3 as shown, are allowed to roll along guide frame C into the nip of the drive wheels. Alternatively, the cricket balls can be introduced into the nip of the drive wheels by a linear actuator, not shown, as disclosed in GB2,430,892A.

The drive wheels IA, 1B and IC are provided with solid polyurethane tyres T in order to ensure that the cricket ball 3 is resiliently gripped as it passes through their nip. The overall diameter of each drive wheel is suitably approximately 230mm (9") and the maximum speed of rotation achievable by the drive motors 2A, 2B and 2C is suitably 6,000 rpm, corresponding to a peripheral velocity approaching 70 ms-1. The gap between the drive wheels is suitably 59mm (2") or slightly less, corresponding to the diameter of a cricket ball. The thickness (ie the axial dimension) of the drive wheels is suitably 76mm (3").

As shown in Figure 8, the angular offset of the upper drive wheel IA can be varied from the centre direction CE (corresponding to a straight delivery) by about +65° or -65°. The appropriate settings can be provided mechanically or electromechanically and optionally can be programmable.

The frame Y is turned to adjust the line (ie direction in the horizontal plane) of the delivery (positive angles being measured anticlockwise, ie in the off direction, and negative angles being measured clockwise i.e. in the leg direction as shown in Figure 8) and the frame F is tilted (positive angles representing an upward tilt). The tilt angle affects the length before pitching. The relative wheel speeds of the upper wheel and the pair of lower wheels in the straight delivery can be varied to apply top spin or back spin as noted above in connection with Figure 1. Top spin will shorten the flight and increase the bounce whereas back spin will project the ball further and flatten the bounce.

In general, the relative wheel speeds can be varied, eg by ±10°0 and the angles can also be varied, eg by +5° The larger the angle the greater will be the swing or break. Increasing the speed of the lower wheels, and thereby reducing the speed differential between the wheels, will result in a lower bounce to replicate the conditions found at different cricket grounds In a variant the frame F could be mounted on a universal joint which allows tilting about an axis orthogonal to the axis of projection and turning (about a vertical axis) from a fixed mounting. The universal joint in this variant would be constrained to prevent significant tilting about the axis of projection. The yoke Y could then be dispensed with.

The types of delivery are shown in Figure 9, wherein 9a) shows a straight delivery towards wicket w On which the angular velocities of the wheels 1A, 1B and 1C are equal).

Figure 9b) shows an in swing resulting from a spin about the vertical axis of the ball and Figure 9c) shows an away swing as a result of a similar spin but in the reverse sense The back spin delivery shown in Figure 9d) is achieved by rotating the lower drive wheels 1B and IC faster than the upper drive wheel 1A, with the upper drive wheel IA in a centred orientation CE resulting in a Yorker. Figure 90 shows the reverse arrangement in which the upper drive wheel rotates faster than the lower drive wheels, resulting in a bouncer.

Figure 90 shows an off break delivery (in which the lower drive wheels rotate faster than the upper drive wheel 1A).

Figure 9g) shows a leg break delivery involving back spin.

Figure 9h) shows an off cutter, and Figure 9i) shows a leg cutter.

Additionally, variants of the above deliveries can be obtained as shown, using similar differentials in wheel speeds and angles Figure 10 shows a complete bowling machine which is in the form of a trolley comprising a frame 11 mounted on a forward and rear pair of wheels 17 and carrying a battery module 15 which supplies power to the motors 2A, 2B and 2C and to an electronic speed control unit 16 which controls the motor speeds and angle of the upper drive motor assembly 1A, 2A, B. Preferably the speed control unit 16 is microprocessor-controlled and allows the user to select any desired delivery. Some or all of the motors are controlled electronically.

At the forward end of the trolley, a sub-frame 13 is pivotally connected about a transverse pivot axis 12 to the frame 11 and carries the transverse supporting bar 6 on which the movable frame assembly 10 is mounted. In normal use, the supporting bar 6 is held in the position shown by fixing bolts 14 which secure it to the underside of the upper rail of frame 11. The supporting bar 6 may also be supported by collapsible air struts (not shown) which can be collapsed only after unscrewing the rising bolts 14. In normal use, the movable frame assembly 10 is pivoted about axis X to a plane orthogonal to the plane of the drawing and bowls balls in the forward direction, i.e. to the left relative to Figure 10.

As shown in Figure 10, the movable frame assembly 10 has been pivoted anticlockwise by 900 to lie parallel to the plane of the drawing. The fixing bolts 14 can then be unscrewed (and if present, air struts collapsed) to allow the movable frame assembly and its supporting sub-frame 13 to rotate downwardly into the interior of frame 11 as indicated by the arrow 20. In this configuration the bowling machine is much more compact and stable and can be transported easily. A best seen in Figure 1, the movable frame assembly is offset from the centre of supporting bar 6 to allow the motor and wheel assemblies on the front of supporting plate 9 to fit within the interior of frame 11.

In a variant, means are provided for sequentially feeding stored balls into engagement with the drive wheels for projection in sequence. The sequence can be controlled by a timer or remote controller. Warning lights are suitably provided to signal the sequence of deliveries.

In other embodiments, balls can be fed singly by hand. :3

In other embodiments, the lower drive wheels could each have a convexly or concavely tapered drive surface rather than a frusto-conical drive surface.

Claims

Claims 1 A three-wheel ball-projecting machine comprising an array of first, second and third counter-rotating drive wheels having spaced-apart peripheral surfaces which cooperatively engage and project a ball and wherein the axis of rotation of the first drive wheel is angularly offsettable so as to impart a spin to the ball about its axis of projection and wherein the second and third drive wheels are tapered, the drive wheels each being coupled to drive means which in use can drive at least two of them with a speed differential to impart a spin orthogonal to the axis of projection.
2 A three-wheel ball-projecting machine according to claim 1 wherein the axes of rotation of the second and third drive wheels are substantially parallel.
3. A three-wheel ball projecting machine according to claim 1 or claim 2 wherein the axis of rotation of the first drive wheel is angularly offsettable out of a common plane of the axes of rotation of the second and third drive wheels
4. A three-wheel ball projecting machine according to any preceding claim wherein the angle of taper of the second and third drive wheels relative to their radial plane is in the range 40° to 80°, preferably 45° to 75° and more preferably 45' to 70°.
5. A three-wheel ball-projecting machine according to any preceding claim wherein said first drive wheel is disposed above said second and third drive wheels.
6 A three-wheel ball-projecting machine according to any preceding claim wherein at least one of said drive wheels is biased towards the other drive wheels by spring means towards so as to accommodate balls of different sizes in the gap between said peripheral surfaces
7 A three-wheel ball-projecting machine according to any preceding claim which is a cricket bowling machine in which the spacing between said opposed peripheral surfaces is such that they can grip a cricket ball, said machine having first means for varying the angular offset of said first drive wheel and second means for varying a speed differential between at least two of the first, second and third drive wheels, said first and second means having settings which in combination correspond to standard cricket deliveries
8 A three-wheel cricket bowling machine according to claim 7 wherein respective setting combinations correspond to at least two of the following cricket deliveries: i) straight ii) in swing iii) away swing iv) leg break v) off break vi) leg cutter vii) off cutter.
9. A three-wheel cricket bowling machine according to claim 7 wherein respective setting combinations correspond to at least one straight delivery, at least one in swing or away swing delivery, and at least one off break or leg break delivery.
10. A three-wheel cricket bowling machine according to claim 7 wherein respective setting combinations correspond to at least one straight, at least one in swing or away swing delivery, and at least one off cutter or leg cutter delivery.
11. A three-wheel cricket bowling machine according to claim 7 wherein respective setting combinations correspond to at least one straight delivery, at least one off break or leg break delivery, and at least one off cutter or leg cutter delivery.
12. A three-wheel cricket ball bowling machine according to any of claims 7 to 11 wherein said axis of rotation of the first drive wheel is angularly offsettable about an axis which lies in a substantially vertical plane
13 A three-wheel cricket bowling machine according to claim 12 wherein the plane of rotation of said first drive wheel is settable to at least three orientations on each side of a central orientation corresponding to a straight delivery.
14 A three-wheel ball-projecting machine according to any preceding claim wherein said first, second and third drive wheels are mounted on a supporting frame which is pivotally mounted for tilting about a substantially horizontal lateral axis.
15. A three-wheel ball-projecting machine according to claim 14 wherein said supporting frame is mounted on a turntable for rotation about a vertical axis.
16. A three-wheel ball-projecting machine according to any preceding claim wherein said drive means comprises three electric motors coupled to the respective drive wheels, and means for controlling the speeds of the electric motors
17. A three-wheel ball-projecting machine according to any preceding claim having programmable means for varying one or more parameters of the machine which determine the type of delivery.
18. A three-wheel ball-projecting machine according to any preceding claim which is standardized to project the ball with deliveries whose parameters are specified by the user.
19. A three-wheel ball-projecting machine according to any preceding claim having means for sequentially feeding stored balls into engagement with said drive wheels for projection in sequence A three-wheel ball-projecting machine according to any preceding claim which comprises a frame carrying said drive-wheels and drive means, a sub-frame supporting said frame at one end of the sub-frame, and a pivotal support supporting the sub-frame at an opposite end of the sub-frame, the sub-frame being rotatable about a substantially horizontal axis to allow the frame and associated drive wheels and drive means to be lowered to reconfigure the machine from a deployed configuration to a transport configuration.21 A three-wheel ball-projecting machine according to claim 20 wherein said frame is oriented transversely when the ball-projecting machine is in a deployed configuration and can be rotated to a longitudinal orientation before rotating the sub-frame to lower the drive wheels and drive means and thereby reconfigure the machine to the transport configuration in which the frame is oriented longitudinally.