Jig Saw Dissection

By: Shayne Welsh

Jig Saw

• Objective– How the saw operates from battery to motor

• This type is also known as a reciprocating saw

Parts

• Power Source

• Trigger/Throttle

• Safety Switch

• Motor

Power Source

• Power source can be either a battery or plug• Batteries range in voltage, depending on model

– 8V– 14.4V

• Using a plug allows a larger motor, so more powerful saw

• Batteries are portable and are able to be used at any worksite

Trigger/Throttle

• The trigger acts as both an ‘On’ switch and a voltage regulator

• As the trigger is squeezed, the connection inside is completed, allowing energy to move from the battery into the motor

• The further the trigger is squeezed the more energy that passes at a given instant

• Causes the motor to accelerate by squeezing harder

Safety Switch

• Safety switches prevents saw from running when unintended

• Plastic object that prevents trigger from being pulled back unless it is moved to the side

• Spring loaded so it reset itself into the ‘safe’ position immediately after being let go

Motor

• Converts electrical energy to mechanical energy, electromagnetism

• Mechanical force on an wire when it is conducting electricity while contained within magnetic field– Perpendicular to both wire and magnetic field– In rotary motor

• Wires and magnetic field are arranged so torque is developed on rotary axis

Motor

• Rotating part is called the rotor

• Stationary part is stator

• Electromagnets are wound on a frame

• Armature– Part of motor which input voltage is supplied

across– Can be either stator or rotor, depending on

model

Motor

Step 1 Step 2 Step 3Magnetic field generated around armature, left side is pushed away form left magnet and drawn toward right

Armature continues to rotate

When armature is horizontally aligned, commutator reverses direction of current through coil, reversing magnetic field and process repeats

Conclusion

• Reciprocating saw operated by motor converting electric energy to mechanical energy

References

• http://www.defusco.com/Images/RS5.jpg

• http://en.wikipedia.org/wiki/Electric_motor#Operation

• http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=6013540126