Mechanisms considered to be an assembly of mechanical items designed to achieve a specific purpose within a machine.

Linear Actuators typically convert rotary motion of a control knob or handle into linear displacement via screws and/or gears to which the knob or handle is attached.

Clamping Mechanisms Clamps result from lever actions, screw forces, toggle motions. The two important factors in the engineering of a clamp is the method of applying a high force and the method of retaining the force after removal of the input motion...

Swinging / Rocking Mechanisms This type of mechanism produces a swinging or rocking motion of a link.   The motion is generally less than 360o and is an oscillatory motion (back and forth).

Reversing Mechanisms It is comparatively easy to obtain reversing motion using pneumatic, hydraulic, levers and gears methods.

Sliding Connectors Sliding connectors are used when one slider is used to drive another slider. The normal problem is that the sliders operate on the same plane but in different directions. Different methods of solving this problem include.

Linkage Linkages are a vital mechanism and many examples can be seen around us. The most common types of linkage are shown below. REVERSE MOTION LINKAGE: As the top rod moves to the left the bottom rod moves to the right. The bars move in opposite directions. Another way of describing this linkage is the direction of movement in one rod is reversed in the other rod. The fixed pivot is the centre of rotation.

Linkage PARALLEL MOTION LINKAGE: As the large rod at the top of the diagram moves to the left the two small rods at the bottom move to the right. All the rods are parallel to each other.

Linkage BELL CRANK LINKAGE: This linkage allows horizontal movement to be converted to vertical movement. It also works the opposite way round. A practical example of this is the brake mechanism on a bicycle.

CAMS and FOLLOWERS A CAM changes the input motion, which is usually rotary motion (a rotating motion), to a reciprocating motion of the follower. They are found in many machines and toys

Pear Cams Pear shaped cams are used on the shafts of cars. The follower remains motionless for about half of the cycle of the cam and during the second half it rises and falls.

Circular cams Circular cams or eccentric cams produce a smooth motion. These cams are used in steam engines.

Heart Cam Heart shaped cams allow the follower to rise and fall with ‘uniform’ velocity.

Drop Cam Drop cams allow the follower to rise and fall with ‘dynamic’ velocity. Also called a trip hammer.

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