Reciprocating Saw
We were interested in this saw particularly because of its claimed “UVP: User Vibration Protection.” We wanted to show some visiting clients something that somewhat related to and may possibly be adapted to their product line.
Saw disassembled…
Front housing of drill (right middle): This housed the gear train, radial to reciprocating motion converter, counter-weight (this is the vibration protection), and the saw blade clamping mechanism.
Rear housing with plastic grip and trigger: The gray housing contains the brushed DC motor.
Plastic covers. They are rigid plastic with an over-molded elastomer to enhance the user grip.
Trigger assembly. The main switch is an on-off control with a trim pot to fine tune the speed. The yellow dial sets the maximum speed of the motor; this is done with a variable resistor to set the primary circuit resistance. The metal can under the yellow wires is an SCR (silicon controlled rectifier) with possibly a rectifier to produce DC voltage to the motor.
Here you can see the motor shaft protruding from the housing. The teeth on this shaft mesh with the large gear in the front housing seen in the left of the image.
The large gear seen receives power from the motor shaft. The U-shaped metal piece surrounding the hollow tube is the counter weight that moves in the opposite linear direction of the blade, thus helping to dampen the vibration passed along to the user.
This gear/shaft assembly is not rigidly fixed to the rotating “bent shaft” that will be identified in following images. Only friction and a pressure angle – seen at the end of the bent shaft here, at the tip of the gear shaft – transmits power to the bent shaft.
Bent shaft with attached collars removed from housing. The ball tips on the collars fit into sockets in blade clamp and the counterweight.
Counter weight with guide shafts removed.
The bend in the shaft causes the ball tips to move in linearly opposite directions as the shaft spins.
Blurry image but one of the ball tips on the collars fit through the obround cut in the hollow shaft and into the blade clamp assembly. The blade clamp assembly reciprocated inside the hollow shaft seen here.
