Fluid meter having a crankshaft with two angularly spaced crank pins radially offset from the crankshaft

A meter for measuring the volume of a fluid flowing therethrough, comprising:

• a body having a crankcase portion and first and second axially-aligned cylinder portions, each of said cylinder portions having an inner end in fluid communication with said crankcase portion, said first and second cylinder portions having respective first and second head ends opposing said inner ends, said body further having a first port, a second port, and a third port in fluid communication with said first head end, said second head ends and said crankcase portion, respectively;
• a crankshaft rotatably mounted in said crankcase portion, said crankshaft including first and second crank pins radially offset from said crankshaft and angularly spaced approximately sixty degrees apart;
• a first piston reciprocally mounted in said first cylinder portion and drivingly connected to said first crank pin so that rotation of said crankshaft is effected by reciprocation of said first piston within said first cylinder;
• a second piston reciprocally mounted in said second cylinder portion and drivingly connected to said second crank pin so that rotation of said crankshaft is effected by reciprocation of said second piston within said second cylinder;
• and
• a rotary valve coupled to said crankshaft and having an inlet port and an outlet port arranged to sequentially register with said first, second, and third ports when said crankshaft is rotated so that fluid flow into said inlet port flows through said body and out through said outlet port, and causes said crankshaft to rotate at a rate proportional to the rate of fluid flow.

A fluid meter comprising:

• a housing defining at least one crankcase and two axially-aligned cylinders;
• a crankshaft disposed in said crankcase;
• first and second pistons respectively mounted in said cylinders for reciprocating movement;
• a first connecting rod having a first end connected to said first piston and a second end slidably engaging said second piston and said crankshaft so that, during movement of said first piston, said first connecting rod is guided by said second piston and said crankshaft is rotated;
• a second connecting rod having a first end connected to said second piston and a second end slidably engaging said first piston and said crankshaft so that, during movement of said second piston, said second connecting rod is guided by said first piston and said crankshaft is rotated;
• and
• wherein said first and second connecting rods are respectively connected to said crankshaft by crank pins that are radially offset from said crankshaft and angularly spaced substantially sixty degrees apart so that said pistons reciprocate substantially sixty degrees out of phase.