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Mechanisms | Definitions
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Mechanisms | Definitions
Spur Gears
Standard straight-cut toothed gears.
Helical Gears
More gradual refined meshing allows for smoother and quieter running than spur gears while also giving greater strength. The teeth are not parallel to the axis of rotation but are set at an angle.
Idler Gears
An additional gear used to change the direction of a gear train, it fits between the two main gears to ensure the driver and driven rotate in the same direction. It does not influence the gear ratio of the system.
Rack and Pinion
A rack and pinion gears system looks quite unusual but it is still composed of two gears. The ‘pinion’ is the normal round gear and the ‘rack’ is straight or flat. The rack has teeth cut into it which mesh with the teeth of the pinion gear while the pinion rotates and moves the rack in a straight line. In other words, ‘rotary motion’ changes to ‘linear motion’.
Worm and Worm Wheel
A worm gear is used in conjunction with a worm wheel to change the angle of rotation through 90° and to slow down a drive. It increases the torque of a driving motor.
Ratchet and Pawl
A mechanical device that allows continuous linear or rotary motion in one direction only while preventing motion in the opposite direction.
Chain and Sprocket
A sprocket is a profiled wheel with cogs which mesh with a chain. The chain is used to transmit motion from one sprocket to another without slip. This system produces a strong drive.
Bearings
These have an inner and outer race between which balls or rollers roll. The outer race is usually fixed, allowing a press-fit shaft to turn freely without friction in the inner race.
Stepped Cone Pulley Mechanism
A mechanism used on machines to allow for speed control. This mechanism consists of two or more conical shaped pulleys joined together.
Hydraulics
A mechanical function that operates through the force of liquid pressure. The common fluids used are petroleum-based, water-based and synthetics.
A Single Acting Hydraulic Ram
A single-acting hydraulic ram has a port at one end, supplied with hydraulic fluid for the extension of the piston. The piston is retracted by a spring or gravity.
Pneumatics
A mechanical function that operates through the force of compressed air or gas.
A Single Acting Cylinder
A pneumatic output device that requires compressed air to make the piston move. If the air is removed the piston will return to its original position.
A Double Acting Cylinder
A double acting cylinder requires compressed air to move the piston. It will stay in this position if the air is turned off. Air from the opposite direction is needed to return the piston to its original position.
Reservoir
Used to create a time delay in a pneumatic circuit, the purpose of the reservoir is to temporarily store air to cater to the demands of the system and to optimise the efficiency of the circuit.
Pneumatic Flow Regulators
Valves that control the flow of pressurised air in one direction in a pneumatic circuit. They can be activated manually or electronically.
SPST Switch
A simple on/off switch. If used in a circuit with a motor it will only allow the motor to rotate in one direction.
DPDT Switch
Used where forward and reverse is required. If a motor is required to rotate in both directions a DPDT switch is used.
Resistor
A resistor will limit current flow and is used to protect electronic components such as LEDs.
Toggle Mechanism
Commonly used as a clamping mechanism (which can be seen on vice grips), it consists of a linkage that is controlled by a lever. A small amount of force on the lever results in a large amount of force on the output linkage.
Cam and Follower Mechanism
Converts rotary motion into reciprocating motion. The cam rotates while the follower moves up and down with the motion.
Capacitor
A capacitor is used to store charge which can be released when needed.
Thermostat
A component of a control system which senses the temperature of a system so that the system’s temperature can be maintained near a desired set-point.
Relay
An electromagnetic device that changes switching contacts when it receives an electric signal. It consists of a wire coil with a soft iron core.
Solenoid
An electrical device where a coil of wire, wound around a soft iron core, is energised. The magnetic force induced by the current pulls the bar towards the centre. A solenoid spring will return the bar to its original position.
Bevel Gears
Bevel gears can be used to change the direction of drive in a gear system by 90 degrees. A good example is the main mechanism for a hand drill. As the handle of the drill is turned in a vertical direction, the bevel gears change the rotation of the chuck to a horizontal rotation.
Heat Sink
A heat sink is used in electronics to conduct away the heat generated by a component. These heat sinks are normally corrugated or finned to dissipate heat to the surrounding air and protect components such as transistors.
Cut dotted horizontal lines. Fold vertical line.
Spur Gears
Standard straight-cut toothed gears.
Helical Gears
More gradual refined meshing allows for smoother and quieter running than spur gears while also giving greater strength. The teeth are not parallel to the axis of rotation but are set at an angle.
Idler Gears
An additional gear used to change the direction of a gear train, it fits between the two main gears to ensure the driver and driven rotate in the same direction. It does not influence the gear ratio of the system.
Rack and Pinion
A rack and pinion gears system looks quite unusual but it is still composed of two gears. The ‘pinion’ is the normal round gear and the ‘rack’ is straight or flat. The rack has teeth cut into it which mesh with the teeth of the pinion gear while the pinion rotates and moves the rack in a straight line. In other words, ‘rotary motion’ changes to ‘linear motion’.
Worm and Worm Wheel
A worm gear is used in conjunction with a worm wheel to change the angle of rotation through 90° and to slow down a drive. It increases the torque of a driving motor.
Ratchet and Pawl
A mechanical device that allows continuous linear or rotary motion in one direction only while preventing motion in the opposite direction.
Chain and Sprocket
A sprocket is a profiled wheel with cogs which mesh with a chain. The chain is used to transmit motion from one sprocket to another without slip. This system produces a strong drive.
Bearings
These have an inner and outer race between which balls or rollers roll. The outer race is usually fixed, allowing a press-fit shaft to turn freely without friction in the inner race.
Stepped Cone Pulley Mechanism
A mechanism used on machines to allow for speed control. This mechanism consists of two or more conical shaped pulleys joined together.
Hydraulics
A mechanical function that operates through the force of liquid pressure. The common fluids used are petroleum-based, water-based and synthetics.
A Single Acting Hydraulic Ram
A single-acting hydraulic ram has a port at one end, supplied with hydraulic fluid for the extension of the piston. The piston is retracted by a spring or gravity.
Pneumatics
A mechanical function that operates through the force of compressed air or gas.
A Single Acting Cylinder
A pneumatic output device that requires compressed air to make the piston move. If the air is removed the piston will return to its original position.
A Double Acting Cylinder
A double acting cylinder requires compressed air to move the piston. It will stay in this position if the air is turned off. Air from the opposite direction is needed to return the piston to its original position.
Reservoir
Used to create a time delay in a pneumatic circuit, the purpose of the reservoir is to temporarily store air to cater to the demands of the system and to optimise the efficiency of the circuit.
Pneumatic Flow Regulators
Valves that control the flow of pressurised air in one direction in a pneumatic circuit. They can be activated manually or electronically.
SPST Switch
A simple on/off switch. If used in a circuit with a motor it will only allow the motor to rotate in one direction.
DPDT Switch
Used where forward and reverse is required. If a motor is required to rotate in both directions a DPDT switch is used.
Resistor
A resistor will limit current flow and is used to protect electronic components such as LEDs.
Toggle Mechanism
Commonly used as a clamping mechanism (which can be seen on vice grips), it consists of a linkage that is controlled by a lever. A small amount of force on the lever results in a large amount of force on the output linkage.
Cam and Follower Mechanism
Converts rotary motion into reciprocating motion. The cam rotates while the follower moves up and down with the motion.
Capacitor
A capacitor is used to store charge which can be released when needed.
Thermostat
A component of a control system which senses the temperature of a system so that the system’s temperature can be maintained near a desired set-point.
Relay
An electromagnetic device that changes switching contacts when it receives an electric signal. It consists of a wire coil with a soft iron core.
Solenoid
An electrical device where a coil of wire, wound around a soft iron core, is energised. The magnetic force induced by the current pulls the bar towards the centre. A solenoid spring will return the bar to its original position.
Bevel Gears
Bevel gears can be used to change the direction of drive in a gear system by 90 degrees. A good example is the main mechanism for a hand drill. As the handle of the drill is turned in a vertical direction, the bevel gears change the rotation of the chuck to a horizontal rotation.
Heat Sink
A heat sink is used in electronics to conduct away the heat generated by a component. These heat sinks are normally corrugated or finned to dissipate heat to the surrounding air and protect components such as transistors.