Page 135 - CITS - Fitter - Trade Theory

FITTER - CITS

4 Rack and Pinion Drive:
• In a rack and pinion system, a linear rack (a toothed bar) meshes with a rotating pinion (a toothed wheel).

• The rack is typically fixed in place, while the pinion rotates about its axis.
• As the pinion rotates, it engages with the teeth of the rack, causing linear motion along the length of the
rack.
• This linear motion can be used to drive the ram or slide of a power press in a controlled manner, allowing
for precise positioning and force application.
5 Knuckle joint drive
• The knuckle joint drive consists of a rotating crankshaft, a connecting rod, and a knuckle joint assembly.

• The crankshaft is driven by a motor or other power source and rotates about its axis.
• The connecting rod is attached to the crankshaft at one end and to the knuckle joint assembly at the other
end.
• The knuckle joint assembly consists of two or more arms connected by pivot joints, forming a flexible linkage

6 Eccentric drive
• An eccentric drive consists of an eccentric shaft, which is a circular shaft with an off-centre pivot point, and
a connecting rod.

• The eccentric shaft rotates about its axis, causing the off-centre pivot point to move in a circular path.
• The connecting rod is attached to the off-centre pivot point of the eccentric shaft and transmits the eccentric
motion to the ram or slide of the power press.
7 Cam drive

• A cam drive consists of a camshaft with one or more cams attached and a follower mechanism.
• The camshaft is a rotating shaft with one or more eccentric lobes, called cams, mounted on it.
• The follower mechanism, which can take various forms such as a roller, lever, or slide, engages with the
cam surface and translates its motion into linear motion.
8 Toggle lever
• A toggle lever consists of a linkage system comprised of two or more levers connected by pivot joints.
• The levers are typically arranged in a triangular or parallelogram configuration, with one end fixed in place
and the other end connected to the ram or slide of the power press.
• The pivot joints allow the levers to rotate relative to each other, creating a mechanical advantage that ampli-
fies the force applied by the press.

9 Crank and connecting rod drive
• The crank and connecting rod drive consists of a crankshaft, connecting rod, and slide mechanism.
• The crankshaft is a rotating shaft with an eccentric or offset crankpin.
• The connecting rod is attached to the crankpin at one end and to the slide mechanism at the other end.
• The slide mechanism is responsible for translating the linear motion generated by the connecting rod into
the desired motion for the press operation.

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CITS : CG & M - Fitter - Lesson 21