The Skil Reciprocating Saw has removeable blades to cut materials ranging from wood to metal.
How It Works
The reciprocating saw runs off a 120 Volt, 8.5 Amp motor. At the end of the motor is a spiral bevel gear that is attached to a scotch yoke mechanism. The scotch yoke mechanism converts circular motion to linear motion. Referring to the avi file below, the mechanism involves a circular gear with a pin connected to a shaft. The linear motion is what moves the saw back and forth in its reciprocating motion.
Analysis in Adams yields a power output of about ¼ horsepower when cutting a medium sized log. As far as the power output is concerned there is not much as far as improvements. If a larger stoke was implemented, the time required to cut would be reduced significantly. However, a larger stoke implies a larger device which will increase material costs.
The shaft connecting to the saw blade runs between 800 and 2700 strokes per minute when it is not cutting. The shaft's motion is controlled by a scotch yoke mechanism that is connected to a gear by a pin in a slot. Using an Adams analysis, the net force acting on the shaft at an average motor speed was 22.02 pounds. This force results in a maximum deflection of the slot connected to the pin of 4.65e-4 inches. Such a deflection shows that the scotch yoke mechanism will be stable when running at very high speeds.
The table belows lists the Bill of Materials for the Reciprocating Saw:
|Part #||Part Name||Category #||Function||Material||Picture|
|1||Trigger||Switch||Control electrical signal||Plastic, copper wires|
|2||Variable speed control||Speed control||Control speed of blade||Plastic, copper wires|
|3||Insulated Bearing||Support Element||Allows rotation of motor||Steel|
|4||Motor||Input||Turns to drive gears||Copper wire, steel wire|
|6||Bearing||Support element||Allows motor and spiral bevel gear to rotate||Steel|
|7||Spiral bevel gear||Transmission motion conversion||Changes direction of rotation from motor||Steel|
|8||Brushes||Input||Electric signal causes motor rotation||Nickel, iron, cobalt|
|9||Shaft||Support element, motion conversion||Convert circular movement to linear||Stainless steel|