Patent GB-388645-A (GB)
Title: Improved manufacture of pottery ware
IPC: B28B13/02
Filed: 1932-06-29
Abstract: 388,645. Moulding pottery-ware. MILLER, W. J., 7337, Schoyer Avenue, Swissvale, Pennsylvania, U.S.A. June 29, 1932, No. 18348. Convention date, Nov. 4, 1931. [Class 87 (ii).] To secure greater flexibility in working, in the mass production of pottery ware, " slugs " or charges sufficient to feed several moulds are preformed and afterwards cut up into separate mould charges for delivery to the ware-forming machines. The machines can thus be remote from the source of production of the slugs, and the distribution of the slugs to particular machines controlled, and the size of the mould charges varied without interrupting production. Formation of the slugs. Figs. 1 and 5 show an intermittently-driven extrusion machine for producing the slugs, the machine preferably having interchangeable die-plates each having alternative delivery openings arranged side by side as shown in Fig. 5 and delivering to a conveyer 18ca. A cam 2w driven by the main machine lowers the member 2r at the appropriate time so that it is pushed along by the extruded bar against the action of the spring 2u to engage a contact 2tl and stop the motor, thus producing bars of definite length. The spring subsequently re-engages the member with the contact 2t to restart the motor. A screw adjustment 2t<3> enables the length of slug to be varied. In some cases the slugs are delivered to angled supports on which they are carried to the moulding-machines and means are provided for ensuring exact location of the slugs on the feeding-belt to which they are eventually transferred. Cutting the slugs into predetermined lengths for moulding separate articles. The slugs carried by the delivery belt 18c, Figs. 10 and 11, are received by regulatable spring-mounted guides 18i, which deliver them between jaws 19, pivoted at 18f until they contact with a stop 18e<1>. Projections 30b on a sliding U- shaped frame, moved in timed relation with the feeding-belt, then close the jaws so that the end of the slug is nipped off and moulded to cylindrical shape in the space 18g. The guides 18i also act as scrapers to remove adherent material from the cutting-jaws after each operation. In a modified construction the jaws carry forward extensions to pre-mould the nose of the slug before cutting it off, means also being provided to compress it vertically after the pre-moulding and before cutting off. In another modification hollow rollers, the interior of which is subjected to vacuum or pressure at will, are used to receive the slug for delivery to the cutting-jaws. Porous belts are used to receive the slugs in another construction. Varying the feed of the slugs to control the weight cut off and controlling the distribution between various machines. The feeding-belt is driven intermittently in one direction only by a one-way roller clutch associated with the sprocket 18c3 and actuated by the rack 14g which is operated in one direction through linkage by a cam 9x on the shaft 9d, Fig. 8, and restored by a spring 19m. The feed is varied by adjustment of the stop 19g<1> to limit the action of the spring, notches providing a coarse adjustment and a micrometer screw 19k a fine adjustment. A latch 21 can be set to hold the rack in its extreme left-hand position, thus cutting off the supply of slugs to any particular machine. In a modified transmission mechanism in which the rack drives the feed belt through pawl-and-ratchet mechanism, provision is made also for a slight automatic retraction of the feeding-belt after each cut, to minimize sticking of the material to the jaws. The sliding rack 14g, Fig. 21, carries a pawl 19g<2> which rotates a ratchet wheel driving the belt so as to compress a spring 19t on the forward stroke. On the idle return stroke the spring retracts the belt to a limited extent. Fig. 14 shows a modified construction in which the retraction is caused by the back pressure from the jaws. The rack 14g drives the belt through the medium of latches 19w engaging the links of a chain secured to the belt. The latches are set to yield at predetermined back pressure by the screws 19x and springs 19y. When delivering the slugs continuously to a machine, they may be actually formed with a space between each, and by manipulation of different carrying belts caused to close the intervening spaces so that they are delivered finally in abutting relation. Moulding the cut-off pieces of the slugs. The moulding trays 5f, Fig. 6, are slung by trunnions between a pair of endless driven chains 5 and are supported during the horizontal runs on tracks 4d, 4e. At the receiving station the chains are slack so that the mould trays can be manipulated without stopping the chains as a whole, in the manner described in Specification 293,023, [Class 87 (ii), Moulding plastic &c. substances]. As the trays come into register with the cut-off slug in the space 18g of the jaws 19, Fig. 10, a plunger attached to the crosshead 9k, Fig. 8, is lowered by the cam-actuated lever 9g to push the cut-off piece into an upper mould section of which the plunger forms part. Simultaneously the lower mould section 10, Fig. 8, is raised by mechanism operated by the cam 10b to compress the material progressively from the centre to the periphery of the moulds. Another cam linkage operates the shaft 13a for driving profiling and trimming mechanism. Fig. 11 shows a moulding-mechanism for hollow-ware such as cups. A porous die 20b or core is fixed in the main mould member 17h and the charge is delivered by a plunger with a porous face 20g through a tube 20c so that it is gradually forced into the space between the die 20b and the main mould walls. Axially-delivered compressed air may assist the moulding process. Rubber rings 20b<1> yield in the event of excessive pressure to permit escape of mould material. Changing the plungers and dies. Sets of bridge-members 9k<1> are provided, bored to receive the stems 20i of various sized plungers, and all fitting into a common ring 9k<4>. The bridge-members are connected by dowels to the crosshead 9k, Figs. 8 and 11. By loosening the nut 50m, Fig. 8, the dowels can be released and the plunger and bridge-piece withdrawn as a unit. The base 29b of the die 20b has a sliding tongue-and-groove connection with the main frame so that it can be withdrawn by a lateral movement after the plunger has been withdrawn. Many of the parts with which the clay contacts have provision for releasing the clay therefrom by compressed air. Specifications 282,072, 310,961, [both in Class 87 (ii), Moulding plastic &c. substances], and 364,181 also are referred to.