Bowling machine
Encyclopedia
In cricket
a bowling machine is a device which enables a batsman to practice (usually in the nets
) and to hone specific skills through repetition of the ball being bowled at a certain length, line and speed. It can also be used when there is no-one available to bowl
, or no one of the desired style or standard.
There are a number of different types of bowling machine available to cricket coaches, each quite different in the ways they achieve the required delivery
, though most allow the use of remote control, so that a coach can be closer to a batsman when the stroke is played.
. These are mounted in a frame such that the wheels are in the same plane, about 7 cm apart (slightly less than the diameter of a cricket ball
). A ball joint
allows the machine a wide range of movement. The whole assembly is mounted on a sturdy tripod
or other frame so that the plane
of the wheels is roughly at the height that a typical bowler would release the ball. A chute delivers the ball between the wheels, protecting the coach’s hands.
The motors are typically powered by a car battery
, and turn in opposite directions. A controller allows variation of the speed of each wheel, allowing the machine to be slowed down for less experienced batsmen, or when the motors are not running at the same speed, swing or spin bowling can be simulated.
These machines will work with any ball of roughly the right size and weight, such as normal cricket ball
s or tennis balls. However, they usually work best with their own balls, which are made of hard plastic, and are covered in dimples. These dimples are to help with the swinging characteristics when this type of delivery is desired.
Fast bowling
This is achieved by setting both wheels to the same speed, as fast as the batsman is able to deal with, although the machine itself would have to be tipped horizontally. The coach can move the machine around slightly to vary the line and length of each ball.
Swing bowling
The plane of the wheels is flat, and the motors are set to run at slightly different speeds. This means the ball will spin about an axis perpendicular to the ground, causing it to swing due to the Magnus effect
. If the ball is spinning anticlockwise (looking from above) the ball will swing from right to left; clockwise spin results in a swing from left to right. This means that if the coach slows down the wheel on one side, ball will swing in that direction. The swing produced in this way is different from normal swing bowling, however - it is much more like a curling ball in football.
Spin bowling
To achieve spin, the machine should be tilted to one side, and the wheels set to different speeds as per swing bowling. It will also probably be necessary to make the machine bowl significantly more slowly. The combined action of the spin imparted by the wheels, and the non-perpendicular axis of that spin will cause the ball to bounce up at an angle.
Seam bowling
This is difficult to achieve since the operator cannot control exactly how the ball will roll into the machine and between the wheels. However, by the law of averages, a ball will occasionally come out with its seam at the correct angle, and bounce unpredictably as a result.
Bouncers
To get balls that bounce unnaturally high or low, the plane of the machine must be set so that it is vertical. Not all machines can do this, simply because their ball joint doesn’t give the required range of movement. To get balls that bounce higher than normal, the lower wheel should spin slightly faster than the upper. Deliveries that bounce much lower than normal are less common and are usually the result of the ball striking a broken-up patch of ground. These balls can still be simulated, however, by increasing the speed of the upper wheel.
A pump is used to provide a flow of air into the chamber that the ball drops into. The airflow pushes the ball along the chamber to rubber ring, or gasket, known as a "restrictor". The restrictor has a hole though it that is sightly smaller than the ball, which the ball presses up against. This seals the hole, so air pressure builds up in the chamber. When the pressure is so great that the restrictor can no longer hold it, the ball bursts though, out of the main body of the machine and into an external tube, which guides it upwards and releases it at the height of a bowler's arm. Machine is not good due to air leakage problem.
's "Slazball" (a hard, small, low-bounce, heavy ball, similar in appearance to a tennis ball but usually red in colour). Neither of these types of ball has a seam.
Programmable bowling machines are intended to overcome some of these limitations by rapidly re-configuring themselves to bowl different types of delivery in quick succession.
A programmable bowling machine called "Merlyn", which its makers claimed could "bowl any ball known to man" http://www.merlynbowling.com/merlyn02.htm received much public attention when it was used by the English cricket team
in the run-up to and during the 2005 Ashes series
.
Originally a one-off, Merlyn was built by Henry Pryor, a cricket coach in Hertfordshire
. Its mechanism has not been publicly revealed, though it is safe to assume it is much more complex than the other machines.
Crucially, the machine was claimed to be able to emulate Shane Warne
's leg break
s, and although he is dismissive of its usefulness http://content-uk.cricinfo.com/ci/content/story/249838.html, the England batsmen disagree, and consider their ability to play spin bowling significantly improved.
The machine, as well as its mechanical abilities, also has significant elements of computer-control built in. It is claimed that it can reproduce an over
from a particular bowler if fed the correct data.
One of the more unnerving aspects of the machine is that it provides no indication of the type of ball it is about to bowl until the ball has left the machine. This forces batsmen to work on their instinctive batting, rather than trying to second guess the bowler.
An improved version is currently in development at Loughborough University
, which will add visual feedback by showing a representation of the bowler projected onto a screen. The ball will be released as the virtual bowler’s hand reaches the hole from which the ball is released. This version of the machine is intended for mass production, so it can be sold to cricket clubs around the world. http://news.bbc.co.uk/sport1/hi/cricket/5014106.stm In the winter of 2009/10 the ECB acquired 20 of the machines, one for each county and two for the performance centre at Loughborough. http://www.cricinfo.com/england/content/current/story/439374.html
Cricket
Cricket is a bat-and-ball game played between two teams of 11 players on an oval-shaped field, at the centre of which is a rectangular 22-yard long pitch. One team bats, trying to score as many runs as possible while the other team bowls and fields, trying to dismiss the batsmen and thus limit the...
a bowling machine is a device which enables a batsman to practice (usually in the nets
Cricket nets
Cricket nets are practice nets used by batsmen and bowlers to warm up and/or improve their cricketing techniques. Cricket nets consist of a cricket pitch which is enclosed by cricket nets on either side, to the rear and optionally the roof. The bowling end of the net is left open...
) and to hone specific skills through repetition of the ball being bowled at a certain length, line and speed. It can also be used when there is no-one available to bowl
Bowling (cricket)
In the sport of cricket, bowling is the action of propelling the ball toward the wicket defended by a batsman. A player skilled at bowling is called a bowler; a bowler who is also a competent batsman is known as an all-rounder...
, or no one of the desired style or standard.
There are a number of different types of bowling machine available to cricket coaches, each quite different in the ways they achieve the required delivery
Bowling (cricket)
In the sport of cricket, bowling is the action of propelling the ball toward the wicket defended by a batsman. A player skilled at bowling is called a bowler; a bowler who is also a competent batsman is known as an all-rounder...
, though most allow the use of remote control, so that a coach can be closer to a batsman when the stroke is played.
Mechanical bowling machines
This type of machine is by far the most common. It is simple, strong and reliable, as well as being able to bowl a useful range of deliveries.How they work
The main mechanism of the machine consists of two heavy wheels, between 30 and 50 cm in diameter, shod with solid or pneumatic rubber tyres, each driven by its own electric motorElectric motor
An electric motor converts electrical energy into mechanical energy.Most electric motors operate through the interaction of magnetic fields and current-carrying conductors to generate force...
. These are mounted in a frame such that the wheels are in the same plane, about 7 cm apart (slightly less than the diameter of a cricket ball
Cricket ball
A cricket ball is a hard, solid leather ball used to play cricket. Constructed of cork and leather, a cricket ball is heavily regulated by cricket law at first class level...
). A ball joint
Ball joint
In an automobile, ball joints are spherical bearings that connect the control arms to the steering knuckles.More specifically, a ball joint is a steel bearing stud and socket enclosed in a steel casing. The bearing stud is tapered and threaded. It fits into a tapered hole in the steering knuckle. A...
allows the machine a wide range of movement. The whole assembly is mounted on a sturdy tripod
Tripod
A tripod is a portable three-legged frame, used as a platform for supporting the weight and maintaining the stability of some other object. The word comes from the Greek tripous, meaning "three feet". A tripod provides stability against downward forces, horizontal forces and moments about the...
or other frame so that the plane
Plane (mathematics)
In mathematics, a plane is a flat, two-dimensional surface. A plane is the two dimensional analogue of a point , a line and a space...
of the wheels is roughly at the height that a typical bowler would release the ball. A chute delivers the ball between the wheels, protecting the coach’s hands.
The motors are typically powered by a car battery
Car battery
An automotive battery is a type of rechargeable battery that supplies electric energy to an automobile. Usually this refers to an SLI battery to power the starter motor, the lights, and the ignition system of a vehicle’s engine...
, and turn in opposite directions. A controller allows variation of the speed of each wheel, allowing the machine to be slowed down for less experienced batsmen, or when the motors are not running at the same speed, swing or spin bowling can be simulated.
These machines will work with any ball of roughly the right size and weight, such as normal cricket ball
Cricket ball
A cricket ball is a hard, solid leather ball used to play cricket. Constructed of cork and leather, a cricket ball is heavily regulated by cricket law at first class level...
s or tennis balls. However, they usually work best with their own balls, which are made of hard plastic, and are covered in dimples. These dimples are to help with the swinging characteristics when this type of delivery is desired.
Fast bowlingFast bowlingFast bowling, sometimes known as pace bowling, is one of the two main approaches to bowling in the sport of cricket. The other is spin bowling...
This is achieved by setting both wheels to the same speed, as fast as the batsman is able to deal with, although the machine itself would have to be tipped horizontally. The coach can move the machine around slightly to vary the line and length of each ball. Swing bowlingSwing bowlingSwing bowling is a technique used for bowling in the sport of cricket. Practitioners are known as swing bowlers. Swing bowling is generally classed as a subtype of fast bowling.-Physics of swing bowling:...
The plane of the wheels is flat, and the motors are set to run at slightly different speeds. This means the ball will spin about an axis perpendicular to the ground, causing it to swing due to the Magnus effectMagnus effect
The Magnus effect is the phenomenon whereby a spinning object flying in a fluid creates a whirlpool of fluid around itself, and experiences a force perpendicular to the line of motion...
. If the ball is spinning anticlockwise (looking from above) the ball will swing from right to left; clockwise spin results in a swing from left to right. This means that if the coach slows down the wheel on one side, ball will swing in that direction. The swing produced in this way is different from normal swing bowling, however - it is much more like a curling ball in football.
Spin bowlingSpin bowlingSpin bowling is a technique used for bowling in the sport of cricket. Practitioners are known as spinners or spin bowlers.-Purpose:The main aim of spin bowling is to bowl the cricket ball with rapid rotation so that when it bounces on the pitch it will deviate, thus making it difficult for the...
To achieve spin, the machine should be tilted to one side, and the wheels set to different speeds as per swing bowling. It will also probably be necessary to make the machine bowl significantly more slowly. The combined action of the spin imparted by the wheels, and the non-perpendicular axis of that spin will cause the ball to bounce up at an angle. Seam bowlingSeam bowlingSeam bowling is a phrase used for a bowling technique in cricket whereby the ball is deliberately bowled on to its seam, to cause a random deviation. Practitioners are known as seam bowlers or seamers....
This is difficult to achieve since the operator cannot control exactly how the ball will roll into the machine and between the wheels. However, by the law of averages, a ball will occasionally come out with its seam at the correct angle, and bounce unpredictably as a result. BouncersBouncer (cricket)In the sport of cricket, a bouncer is a type of delivery, usually bowled by a fast bowler. It is pitched short so that it bounces on the pitch well short of the batsman and rears up to chest or head height as it reaches the batsman.Bouncers are used tactically to drive the batsman back on to his...
To get balls that bounce unnaturally high or low, the plane of the machine must be set so that it is vertical. Not all machines can do this, simply because their ball joint doesn’t give the required range of movement. To get balls that bounce higher than normal, the lower wheel should spin slightly faster than the upper. Deliveries that bounce much lower than normal are less common and are usually the result of the ball striking a broken-up patch of ground. These balls can still be simulated, however, by increasing the speed of the upper wheel.Pneumatic bowling machines
This design is significantly less common than the mechanical type and operates using a completely different principle.How they work
Most of the space in the machine is a hopper that contains the balls. At the bottom of the hopper, near the front, is a rotor with space for six balls. The balls slot into the spaces on the rotor by gravity, which then takes them into the innards of the mechanism. The rotor passes over a trap-door, which the ball opens with its weight, falling into a small chamber.A pump is used to provide a flow of air into the chamber that the ball drops into. The airflow pushes the ball along the chamber to rubber ring, or gasket, known as a "restrictor". The restrictor has a hole though it that is sightly smaller than the ball, which the ball presses up against. This seals the hole, so air pressure builds up in the chamber. When the pressure is so great that the restrictor can no longer hold it, the ball bursts though, out of the main body of the machine and into an external tube, which guides it upwards and releases it at the height of a bowler's arm. Machine is not good due to air leakage problem.
Fast bowling
A system exists that allows air to escape from the barrel shortly after it has passed the restrictor. This reduces the pressure on the ball, reducing its muzzle velocity. Closing this increases the speed to its maximum.Swing bowling
To do this a curved piece of tubing is attached to the end of the barrel. The ball rolls around this causing it to spin and swing.Spin bowling
The tubing used for swing bowling can also be used for spin bowling, by pointing the curve somewhere between vertical and horizontal.Seam bowling
Seam bowling is impossible on this machine as it only accepts tennis balls and cricket training balls such as SlazengerSlazenger
Slazenger is a British sports equipment brand name sold throughout the world, involving a variety of sporting categories namely cricket, tennis and hockey...
's "Slazball" (a hard, small, low-bounce, heavy ball, similar in appearance to a tennis ball but usually red in colour). Neither of these types of ball has a seam.
Bouncers
The tubing can again be used, this time to simulate high and low bounce by mounting the tube vertically.Programmable bowling machines
Both of the types of machines described above are fairly simple designs, intended for regular, hard use by clubs, and hence are simple to operate and reliable. They can only simulate one type of delivery with the machine in a given configuration and have other limitations, particularly with spin bowling, which limit their usefulness to players at the highest levels of the game.Programmable bowling machines are intended to overcome some of these limitations by rapidly re-configuring themselves to bowl different types of delivery in quick succession.
A programmable bowling machine called "Merlyn", which its makers claimed could "bowl any ball known to man" http://www.merlynbowling.com/merlyn02.htm received much public attention when it was used by the English cricket team
English cricket team
The England and Wales cricket team is a cricket team which represents England and Wales. Until 1992 it also represented Scotland. Since 1 January 1997 it has been governed by the England and Wales Cricket Board , having been previously governed by Marylebone Cricket Club from 1903 until the end...
in the run-up to and during the 2005 Ashes series
2005 Ashes series
The 2005 Ashes series was that year's edition of the long-standing and storied cricket rivalry between England and Australia. Starting on 21 July 2005, England and Australia played five Tests, with the Ashes held by Australia as the most recent victors...
.
Originally a one-off, Merlyn was built by Henry Pryor, a cricket coach in Hertfordshire
Hertfordshire
Hertfordshire is a ceremonial and non-metropolitan county in the East region of England. The county town is Hertford.The county is one of the Home Counties and lies inland, bordered by Greater London , Buckinghamshire , Bedfordshire , Cambridgeshire and...
. Its mechanism has not been publicly revealed, though it is safe to assume it is much more complex than the other machines.
Crucially, the machine was claimed to be able to emulate Shane Warne
Shane Warne
Shane Keith Warne is a former Australian international cricketer widely regarded as one of the greatest bowlers in the history of the game. In 2000, he was selected by a panel of cricket experts as one of the five Wisden Cricketers of the Century, the only specialist bowler selected in the quintet...
's leg break
Leg break
A leg break is a type of delivery in the sport of cricket. A delivery of a right-handed leg spin bowler. Leg breaks are also colloquially known as leggies or wrist spinners, as the wrist is the body part which is primarily used to impart spin on the ball, as opposed to the fingers in the case of...
s, and although he is dismissive of its usefulness http://content-uk.cricinfo.com/ci/content/story/249838.html, the England batsmen disagree, and consider their ability to play spin bowling significantly improved.
The machine, as well as its mechanical abilities, also has significant elements of computer-control built in. It is claimed that it can reproduce an over
Over (cricket)
In the sport of cricket, an over is a set of six consecutive balls bowled in succession. An over is normally bowled by a single bowler. However, in the event of injury preventing a bowler from completing an over, it is completed by a teammate....
from a particular bowler if fed the correct data.
One of the more unnerving aspects of the machine is that it provides no indication of the type of ball it is about to bowl until the ball has left the machine. This forces batsmen to work on their instinctive batting, rather than trying to second guess the bowler.
An improved version is currently in development at Loughborough University
Loughborough University
Loughborough University is a research based campus university located in the market town of Loughborough, Leicestershire, in the East Midlands of England...
, which will add visual feedback by showing a representation of the bowler projected onto a screen. The ball will be released as the virtual bowler’s hand reaches the hole from which the ball is released. This version of the machine is intended for mass production, so it can be sold to cricket clubs around the world. http://news.bbc.co.uk/sport1/hi/cricket/5014106.stm In the winter of 2009/10 the ECB acquired 20 of the machines, one for each county and two for the performance centre at Loughborough. http://www.cricinfo.com/england/content/current/story/439374.html