Search results
Results from the WOW.Com Content Network
A ratchet consists of a round gear or a linear rack with teeth, and a pivoting, spring-loaded finger called a pawl (or click, in clocks and watches [1] [2]) that engages the teeth. The teeth are uniform but are usually asymmetrical, with each tooth having a moderate slope on one edge and a much steeper slope on the other edge.
The core of the keyless mechanism is a gear on the watch's winding stem, the clutch (or castle wheel in Britain), with two sets of axial gear teeth on it, which slides in and out. When the stem is pushed in, a lever slides the clutch out, and the outer set of teeth engages a small wheel train which turns the mainspring arbor, winding the ...
The single turnover notch positioned on the left side (plate connector side) of the rotor triggers the stepping motion by engaging the ratchet teeth of the wheel to the left. Later rotors had two turnover notches. The table below lists the turnover notch point of each rotor.
The most common locking mechanism is a handle ratchet, which consists of an asymmetrically serrated short protrusion near the finger loop of one of the handles, and a corresponding hook on the other. As the forceps are closed, the opposing teeth engage and interlock, keeping the handles adducted and the jaw surfaces clamped constantly.
When the stem is pushed in, the outer teeth turn the ratchet wheel on top of the mainspring barrel, which turns the shaft that the inner end of the mainspring is attached to, winding the mainspring tighter around the shaft. A spring-loaded pawl or click presses against the ratchet teeth, preventing the mainspring from unwinding. When the stem ...
At rest one of the escape wheel teeth will be locked against a pallet. As shown in the diagram, the escape wheel rotates clockwise and the entrance tooth is locked in place against the entrance pallet, the lever held in place by the left banking pin. The impulse pin is located within the lever fork and the balance wheel is near its center position.
The arbor has a ratchet attached to it, with a click to prevent the spring from turning the arbor backward and unwinding. After winding, the arbor is stationary and the pull of the mainspring turns the barrel, which has a ring of gear teeth around it. This meshes with one of the clock's gears, usually the center wheel pinion and drives the ...
Universal numbering system. This is a dental practitioner view, so tooth number 1, the rear upper tooth on the patient's right, appears on the left of the chart. The Universal Numbering System, sometimes called the "American System", is a dental notation system commonly used in the United States. [1] [2]