Patent GB-611856-A (GB)
Title: Improvements in or relating to the manufacture of pottery and like articles
IPC: B28B11/18
Filed: 1946-05-10
Abstract: 611,856. Grinding pottery. SULZER BROS. (LONDON), Ltd., WEDGWOOD & SONS, Ltd., J., and WEDGWOOD, C. T. May 10, 1946, No. 14213. [Class 60] [Also in Group X] A machine for applying a finishing operation to pottery or like plastic articles of circular form, e.g. plates, in the raw or partly finished state, comprises a rotatable head B<SP>1</SP> carrying at least one rotatable spindle C, a suction chuck E on the spindle or each spindle, driving mechanism B<SP>3</SP> such as a Geneva wheel for imparting step-by-step rotation to the head so that the chuck or each chuck is moved in sequence to at least three stations, including a station C<SP>2</SP> at which the article is automatically centred and raised on a mould into engagement with the chuck, a station at which, while rotation is imparted to the chuck, a surfacing treatment is applied to the article and a discharge station C<SP>5</SP>, and distributing valve mechanism C<SP>8</SP> operated in synchronism with the head so as to maintain the chuck connected to a source of suction at the times it is required to carry the article and to atmosphere or a source of pressure when it is to release the article. In the machine shown, a plate E<SP>1</SP> supported on a mould is lowered by a chain conveyer H into one of the sockets F<SP>2</SP> of a transfer device F<SP>1</SP> rotated by Geneva wheel mechanism F<SP>3</SP> in synchronism with the head. The plate and mould are then moved one step to the station C<SP>2</SP> and a ram G operated by a cam G<SP>1</SP> on a shaft G<SP>2</SP> rises and lifts the plate and mould past centring fingers J-J<SP>3</SP> into engagement with the chuck, the ram then descending to return the mould into its socket. The head B<SP>1</SP> then moves one step to station C<SP>3</SP> where a drive pulley C<SP>11</SP> on the spindle is engaged with a belt K<SP>2</SP> driven by an electric motor K, and a ram L operated by a cam L<SP>1</SP> on the shaft G<SP>2</SP> rises to engage an abrasive block L<SP>3</SP> with the undersurface of the plate, after which the rams descends. The head then moves to station C<SP>4</SP> where the edge of the plate is trimmed by a knife, the empty mould having by this time been carried round to a position where it is lifted off the transfer device by the chain conveyer. Finally, the head moves to station C<SP>5</SP> where the chuck is connected to atmosphere or to a source of pressure so that the plate is deposited on a table N which is driven by a belt and pulley from the shaft B driving the head. The fingers J-J<SP>3</SP> of the centring mechanism, Figs. 5 and 6, have radially adjustable pivots J<SP>6</SP> and normally occupy the position shown in Fig. 6 so that when they are engaged by the rising mould E<SP>4</SP> their inner ends move radially inwardly to centre the plate on the mould. The fingers J, J<SP>2</SP> carry adjustablymounted rollers J' which ride over the mould as it is moved by the transfer device. In a modification, Fig. 10, the fingers are replaced by plungers O slidable against the action of springs O<SP>4</SP> in guides O<SP>1</SP> pivoted at O<SP>2</SP> and normally held in the position shown by springs O<SP>5</SP>. Each plunger is connected to a Bowden cable O<SP>6</SP> operable through linkage by cam on the shaft G<SP>2</SP>, and, as the mould rises and engages the guides, the plungers are moved inwardly to centre the plate. The knife M, Fig. 8, is mounted between rubber blocks in a clamp M<SP>4</SP>, adjustable on a guide M<SP>5</SP> by a screw M<SP>6</SP>, this guide being mounted on a further guide M<SP>7</SP> along which it may be adjusted by a screw M<SP>8</SP>. The suction chuck E, Fig. 4, includes a valve E<SP>2</SP> operable by a tappet E<SP>3</SP> engaged by the plate, so that the chuck is in communication with the valve mechanism C<SP>8</SP> through a gland C<SP>6</SP> and pipe C<SP>7</SP> only when the plate is engaged with or close to the chuck.