Pg.1_86Applied Forces and Fasteners

A set of flashcards designed to review fundamental concepts of forces, levers, and fasteners, promoting understanding of mechanics in practical applications.

What is the definition of a lever?

A lever is a rigid bar that rotates around a pivot point, called the fulcrum.

What is the purpose of the fulcrum in a lever?

The fulcrum is the pivot point around which the lever rotates.

What do we call the force applied to move a load using a lever?

The applied force is referred to as the effort force (F1).

How is the moment of force (torque) calculated?

Torque is calculated as Torque = Force x Distance.

What is the mechanical advantage (MA) formula for levers?

MA = F2/F1, where F2 is the output force and F1 is the input force.

What happens when D1 is greater than D2 in terms of mechanical advantage?

If D1 is greater than D2, it results in a mechanical advantage in force.

What characterizes a Class 1 lever?

In a Class 1 lever, the fulcrum is located between the effort force and the resistance force.

Provide an example of a Class 2 lever.

Examples of Class 2 levers include wheelbarrows and nutcrackers.

What distinguishes a Class 3 lever from Class 1 and Class 2 levers?

In a Class 3 lever, the effort force is located between the fulcrum and the resistance force, requiring greater force to move the load.

What equation shows equilibrium in levers?

F1 x D1 = F2 x D2.

What is torque's relationship with distance from the pivot point?

Torque increases as the distance from the pivot point increases.

How is the torque expressed in terms of force and distance?

Torque = Force x Distance to the fulcrum.

What is the primary use of torque in practical applications?

Torque is used to turn or rotate objects around a pivot point.

Define shear pins and their purpose.

Shear pins are designed to break under excessive stress to prevent damage to machinery.

Differentiate between regular screws and self-tapping screws.

Regular screws require pre-tapped holes, while self-tapping screws create their own threads as they are driven into material.

What is the purpose of a lock washer?

Lock washers prevent loosening of bolts or screws due to vibration or dynamic loads.

Why is proper torque important for bolts?

Proper torque ensures that bolts maintain adequate clamping force without stripping or breaking.

What is the recommended tightening sequence for multiple bolts?

Tighten the bolts in stages and follow a specific sequence, often starting at the center and working outwards.

Explain the role of washers in bolted joints.

Washers distribute load over a broader surface to prevent damage and help maintain tightening.

What is a common problem associated with fasteners over time?

Fasteners can become loose due to factors like vibration, embedding, or differential thermal expansion.

What type of thread is commonly used for general hardware in the US?

Unified National Threads (UN) are used for general hardware in the US.

What is the effect of lubrication on the rated torque of a fastener?

Lubrication usually decreases the rated torque of a fastener due to reduced friction.

Define torque multiplexers and their use.

Torque multiplexers are devices that amplify the leverage applied to a fastener for easier tightening.

What is a pull-through blind rivet?

A pull-through blind rivet has a pull stem that expands the body of the rivet when tension is applied.

Why is a primer used with threadlockers?

Primers enhance adhesion and curing of threadlockers, especially on inactive metals.

How should safety wire be installed?

Safety wire is threaded through holes in fastener heads to prevent loosening, twisted tightly to secure.

What is match marking and its purpose?

Match marking involves marking bolts and surfaces to ensure they are correctly aligned and identifying loosening.