拍品專文
COMPARATIVE LITERATURE
Tom Robinson, The Longcase Clock, Antique Collectors' Club, 1981, pp. 387-393
The following is taken from a label to the inside of the trunk door; John Ellicott F.R.S., 1706-1772, succeeded his father in 1728. In 1736 he invented a form of compensating pendulum on which expansion bars acted on horizontally pivotted levers inside the pendulum bob in order to raise and lower it up or down the rod as necessary. This ingenious pendulum is said to have been disappointing as it was apt to become jerky in action after a while.
On this regulator the compensating mechanism takes the form of a stout steel bar firmly anchored to the front plate of the movement and projected some 11 in. below it. At its lower end, this steel anchorage bar carries a brass block on which is mounted a stout brass expansion bar which extends upwards and slightly above the top lever of the front plate. At its upper extremity the expansion bar is slotted to engage a counterweighted rocking lever carrying moveable "chops" embracing the suspension spring. The heavy platform carrying the rocking lever and the suspension block etc. is provided with an adjusting arrangement and capstan screw to enable the degrees of movement of the compensating mechanism to be set within fine limits. There are also adjustable jaws below the suspension hook to lock the suspension spring and secure it against rocking; these moveable jaws also carry adjustable friction rollers to guide the moveable "chops".
Tom Robinson, The Longcase Clock, Antique Collectors' Club, 1981, pp. 387-393
The following is taken from a label to the inside of the trunk door; John Ellicott F.R.S., 1706-1772, succeeded his father in 1728. In 1736 he invented a form of compensating pendulum on which expansion bars acted on horizontally pivotted levers inside the pendulum bob in order to raise and lower it up or down the rod as necessary. This ingenious pendulum is said to have been disappointing as it was apt to become jerky in action after a while.
On this regulator the compensating mechanism takes the form of a stout steel bar firmly anchored to the front plate of the movement and projected some 11 in. below it. At its lower end, this steel anchorage bar carries a brass block on which is mounted a stout brass expansion bar which extends upwards and slightly above the top lever of the front plate. At its upper extremity the expansion bar is slotted to engage a counterweighted rocking lever carrying moveable "chops" embracing the suspension spring. The heavy platform carrying the rocking lever and the suspension block etc. is provided with an adjusting arrangement and capstan screw to enable the degrees of movement of the compensating mechanism to be set within fine limits. There are also adjustable jaws below the suspension hook to lock the suspension spring and secure it against rocking; these moveable jaws also carry adjustable friction rollers to guide the moveable "chops".