Activity 6.3 Product Observation Example

Activity 6.3 Product Observation Example

Product Name: Stapler

Company Name: Bates Model 640 Custom

1. What is the purpose or primary function of the object?

This device is designed to perforate and mechanically bind sheets of paper together using metal wire.

2. Sketch an isometric pictorial of the product and label the individual components. If you are not sure what a particular component is called, then make a logical guess.

Sketch from engineering notebook

3. Make an educated guess as to how this product operates. Use simple machines’ terminology to explain the operation.

The top portion of the stapler serves as a lever arm and rotates about a pivot pin. The pivot pin functions as a fulcrum. An effort force is applied downward on the end of the lever arm, which moves the top assembly down toward a small metal plate, called the anvil. The top assembly consists of the top portion of the stapler and the magazine.

The magazine, which is located on the underside of the lever arm assembly, is compressed against the corner of a stack of papers that rests on top of the anvil. The top portion of the stapler continues to move downward, which causes a single piece of metal wire, bent in an upside down U-shape, to be ejected from the magazine. The ends of the wire are small enough in diameter to puncture several sheets of stacked paper. The wire is pushed through the paper until it contacts the anvil.

The anvil has two indentations that function as inclined planes. These inclined planes cause the wire ends to deform and hook inward toward each other as the wires continue to make their way through the paper sheets. The hooked ends form a mechanical connection that binds the papers together. When the U-shaped wire bottoms out on the top sheet of paper, the stapling action is complete.

Force is removed from the top portion of the stapler and the lever returns to its original position, as if it were pushed by some internal force. This action seems to automatically reset the magazine to eject another metal wire staple when the process is repeated.

4. Identify the system inputs, intended product function, and outputs in the table below.

Staples / Noise
Loose paper / Fasten paper / Heat
Applied force / Bent staple

5. What mechanical components are visible?

Base plate, riser, pivot pin, magazine, anvil, upper stapler lever arm

6. What is it about this device’s function that you cannot identify because the mechanical components are hidden from plain view?

It is not obvious what is causing the magazine to advance another staple after each cycle.

It is also not obvious what is causing the lever arm assembly to return to its original position.