Question

Which of the following is true for proper knife registration?

• A. Mid-point of the stroke is centered between adjacent guards
• B. Outer end of cutter bar is ahead of inner end
• C. The knife is in line with pitman
• D. Both the ends of cutter bar are at same level

Hint:

Registration is all about the symmetry of the cutting stroke. Centering on the guards at both ends means the midpoint of the travel must be centered between the guards.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Knife registration in reciprocating mowers refers to the alignment of the knife sections relative to the cutter bar guards at the extreme limits of the stroke.

Step 3: Detailed Explanation:
Let us analyze the conditions:
1.

Knife Registration: A mower knife is in proper registration when the center of each knife section lines up exactly with the center of its corresponding guard at each end of the stroke.
2. If the knife registers properly at both ends of a standard stroke, then by geometric symmetry, the midpoint of the knife stroke must lie exactly midway between adjacent guards. Thus, Statement (A) is correct.
3.

Lead of cutter bar: Having the outer end of the cutter bar slightly ahead of the inner end is called cutter bar lead (Statement B), which compensates for backward deflection during operation.
4.

Pitman alignment: Ensuring the knife is in line with the pitman (Statement C) represents alignment rather than registration.

Step 4: Final Answer:
The correct option is 1, which corresponds to "Mid-point of the stroke is centered between adjacent guards".