Back to the AWF
OK...... so here is my 2 cents .............................. >>>>May 20 2012 at 11:16 AM
No score for this post
Leslie S (Login LES2900)
AWF Approved Poster
from IP address 22.214.171.124
Response to From Pellaton to Magic Lever: auto-winding by excentric pawls...
Abraham-Louis Perrelet working on a watchThe Swiss watchmaker Abraham-Louis Perrelet is said to have invented a self-winding mechanism in the 1770s for pocket watches. It worked on the same principle as a modern pedometer, and was designed to wind as the owner walked, using an oscillating weight inside the large watch that moved up and down. The Geneva Society of Arts reported in 1776 that 15 minutes walking was necessary to wind the watch sufficiently for eight days, and the following year reported that it was selling well. However recently, the case has been made against the Perrelet hypothesis by pointing out that the first drawing and accurate description of an automatic watch was created in 1778 by Hubert Sarton fr:Hubert Sarton and that it is uncertain that the Perrelet watch was actually based on a rotor principle"
1780Perrelet sold some of his watches to a contemporary watch making luminary, Abraham-Louis Breguet around 1780 who improved upon the mechanism in his own version of the design, calling his watches "perpetuelles" the French word for perpetual. They did not work reliably and Breguet stopped producing them around 1800"
" 'Bumper' wristwatches: 1923
First automatic wrist watch, Harwood, ca. 1929 (Deutsches Uhrenmuseum, Inv. 47-3543Self winding mechanisms were more successful in wristwatches than in pocket watches because the arm moves more during daily activity than the torso. The first self-winding wristwatch did not appear until after World War I, when wristwatches became popular. It had been invented in 1923 by John Harwood, a watch repairer from Bolton who took out a UK patent with his financial backer, Harry Cutts, on 7 July 1923, and obtained a corresponding Swiss patent on 16 October 1923. The Harwood system used a pivoting weight which swung as the wearer moved, winding the mainspring. The ratchet mechanism wound the mainspring only when moving in one direction. The weight did not rotate a full 360°; spring bumpers limited its swing to about 180°, to encourage a back and forth motion. This early type of self-winding mechanism is now referred to as a 'hammer' or 'bumper'.
When fully wound, Harwood's watch would run for 12 hours autonomously. It did not have a conventional stem winder, so the hands were moved manually by rotating a bezel around the face of the watch. The watches were first produced with the help of Swiss watch manufacturer Fortis and went on sale in 1928. 30,000 were made before the Harwood Self-Winding Watch Company collapsed in 1931 in the depression. 'Bumper' watches were the first commercially successful automatic watches; they were made by several high grade watch manufacturers during the 1930s and 1940s"
The Rolex Watch Company improved Harwood's design in 1930 and used it as the basis for the Rolex Oyster Perpetual, in which the centrally mounted semi-circular weight could rotate through a full 360° rather than the 300° of the 'bumper' winder. Rolex's version also increased the amount of energy stored in the mainspring, allowing it to run autonomously for up to 35 hours.
By the 1960s, automatic winding became standard in quality mechanical watches. Because the weighted rotor needed in an automatic watch takes up a lot of room in the case, increasing the thickness of the watch, some high end watch companies, such as Patek Philippe, continue to design manually wound watches, which can achieve a case thickness as low as 1.77 millimeters."
I don`t make things. I make things better !
Scoring disabled. You must be logged in to score posts. Respond to this message Responses