Automatic Cloth-Shearing Machine (Cropping the Nap)

Lower blade r dropping to reach the nap-roots

As the shears close, the lower blade r must drop so it can enter to the very roots of the nap. Because the blade is pivoted at t, its back a rises as r descends. Since blade r needs only a little lowering, the ring n is made to strike against the knee m.

Wedge a adjusting the depth of cut

A wedge, a, raises or lowers the cutting blade so the machine can crop more or less nap at one pass than another. It sets the depth of the cut. The labels n m and a mark the parts.

Simplest arrangement, cloth travelling toward f

In the simplest arrangement the part a has no rozena, which is better because there is less pivot to wear away. As the cloth travels toward f it meets the shear-blade, which lifts the nap lying flat and crops it cleanly. Leonardo calls this the simplest mode that can be used.

Why the cloth must be still at the instant of cutting

The thread p q drives the cloth against the shears while they are open and lets it stop while they cut; the two guide-irons m n can each steer a pair of shears. Leonardo argues the cloth must not move during the cut: if it ran continuously, the part begun at first contact would have shifted before the blades finished closing, leaving a strip of uncut nap. Keeping the cloth still makes the cut line straight and between equal angles with its sides.

A sinistra Figura colle lettere:

Figure colle lettere:

Figura colla lettera:

A destra Figura con lettere e parole:

Figura colle lettere:

On the left. Figure with the letters:

Figures with the letters:

Figure with the letter:

On the right. Figure with letters and words:

Figure with the letters:

Automatic Cloth-Shearing Machine (Cropping the Nap)

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Lower blade r dropping to reach the nap-roots

Wedge a adjusting the depth of cut

Simplest arrangement, cloth travelling toward f

Why the cloth must be still at the instant of cutting