Patent GB-835103-A (GB)
Title: Improvements in or relating to grinding mills
Inventor: TUNLEY ALLAN ASHMEAD
IPC: B02C7/14
Filed: 1955-12-23
Abstract: 835,103. Disc mills. BAKER PERKINS Ltd. March 25, 1957 [Dec. 23, 1955], No. 36952/55. Class 59 In a grinding unit for grinding cocoa nibs or cocoa liquor, in which a rotatable annular grinding member co-operates with a stationary annular grinding member on each side thereof, the rotatable grinding member is suspended on, and rotated through, universal joint means interposed between the rotatable grinding member and its axial driving shaft, and one of the stationary grinding members is mounted for limited universal movement with respect to the axis of rotation of the rotatable grinding member. As shown, a rotatable grinding member 1 comprises a supporting web 4 faced on each side by grinding plates 5, 5a which co-operate with grinding plates 28, 26 on upper and lower stationary grinding members 2, 3 respectively. A shaft 6 disposed co-axially of the grinding members is journalled in bearings 7, 8 and is driven by means of gearing 9, 11 from a motor-driven shaft 12. Secured to the shaft 6 by means of a pin 13 is a multi-start feed worm 15 having at its lower end two depending lugs 16 provided with apertures 17 in which are received pivot pins 18 which engage in recesses 19 in a spider 20 so that the latter pivots on an axis X-X, Fig. 3. Two arms 21 projecting from the spider terminate in trunnions 22 which are received and secured in recesses 23 in web 4 of the central grinding member 1 so that the latter pivots about an axis Y-Y perpendicular to the axis X-X. The plate 28 of the upper grinding member 2 is secured to a circular bed 29 which is carried by projecting pins 30, Fig. 4, aligned on a diametral axis A-A and pivotally received in bearing apertures 31 in a ring 32 surrounding the grinding member 2. The ring 32 is pivotally mounted on pins 33 disposed' on an axis B-B perpendicular to the axis: A-A, one of the pins 33 being carried on: a hinged bracket 34 and the other pin on a vertically adjustable bracket 35, the adjustment being controlled by a hand wheel 65 to which is fitted a calibrated device to indicate the position of the grinding member 2. The shaft 6 has clamped thereto a sleeve 40, Fig. 1, which serves as the internal mounting of the bearing 8, the centre ring 41 of which is secured in a surrounding annular member 44 in screw-threaded engagement with the stationary structure 45 of the machine so that by rotating the member 44, by means of a manually-operable worm 49 engaging a worm-wheel 48, the shaft 6 and central grinding member 1 are displaced axialy. Associated with the worm-wheel 48 is a coaxial calibrated disc 51 co-operating with a pointer 52 on the machine structure 45. A pair of calibrated discs may be provided. Alternatively, the shaft 6 may be carried on a bearing supported axially on a compression spring, the loading of which can be varied by adjustment of an abutment at the other end of the spring from the bearing. The effective termination (or delivery) points of alternate threads 101, 102 of the feed worm 15 are such as to deliver the material to the levels of the upper pair 5, 28 and lower pair 5a, 26 of grinding surfaces respectively so that both pairs of grinding surfaces are fed simultaneously as the feed worm rotates. An arcuate wall 103 spaning each of the threads 102 prevents feed from the threads 102 to the upper pair of grinding surfaces. A coned deflector member 104 swept by scraper blades depending from the feed worm assists in feeding material delivered by the threads 102. The material is delivered from the periphery of each pair of grinding surfaces 5, 28 and 5a, 26 into separate con- ,duit systems 120, 122 and 121, 123 having inspection points 118, 119 respectively after which points the conduit systems may combine. The central grinding member 1 is preferably formed with a peripheral flange 124 and extension members 125 overlying the open tops of the separate collecting conduits 120, 121 and carrying blades or scrapers 126 depending into the conduits to impel the collected material to its outlet points. The mill may comprise two or more vertically superposed grinding units and shoot or conduit means to feed and deliver from each unit, alternative shoot or conduit means and diverter flaps or equivalent means being provided for varying which feed or delivery shoots or conduit means are to be utilized according to the requirements of the starting material or product.