Patent GB-656899-A (GB)
Title: Material crushers
IPC: B02C25/00
Filed: 1948-04-20
Abstract: 656,899. Disc mills. ELDRIDGE, J. A. April 20, 1948, No. 10888. [Class 59] A disc mill comprises in one form, Figs. 1, 2 and 4, a stationary disc E and a rotary disc D which, together with a feed screw B and adjustable delivery fan blades 43, is supported and driven by a holder 40 secured to a drive pulley F mounted by means of bearings 32, 33 on a stationary but axially-adjustable shaft 1. The end of the latter is in screw-threaded engagement with a rod 3 carrying a collar 26 which normally abuts against a shoulder 27 on an element 7 of the mill casing in which the shaft is keyed for sliding movement, the exterior of this element being formed with spiral grooves engaged by a similarly grooved barrel cam 8 under the faction of a spring 9. The cam 8 carries a lever 9<SP>1</SP> normally retained in a recess 10 in a locking member 11 which is also slotted to receive' a second lever 12 urged upwardly by ;a spring 14 and carrying a ratchet 52 normally engaged by a pawl 13 on the lever 9<SP>1</SP>, the second lever being bent at its lower end for connection to a pivoted gate valve 4 controlling the discharge 'from the feed hopper A. A graduated adjusting handwheel is screwed on to the rod 3 to load the spring 9 to a desired extent-this loading being such that normal variations of feed will not affect the setting of the discs but the to rotary disc may yield if an obstruction is encountered-and is then locked to the rod by a split pin. Subsequent rotation of the handwheel then' adjusts the spacing of the discs. If a foreign body enters between the discs the lever 9<SP>1</SP> is moved upwardly by the operator so that it may swing to the right under the action of the spring 9 and cam 8, this movement disengaging the pawl 13 from the ratchet and allowing upward movement of the lever 12 to close the valve 4. ,At the same time the shaft 1 is moved to the left to separate the grinding discs. The discs and valve may then be reset by returning the lever to the recess a ramp 50 being formed on the member 11 to assist this ation, and depressing the lever 12 until the pawl and ratchet are engaged with the valve 4 open. The maximum opening of the valve is determined by the engagement with the member 11 of a pin '60 which may be inserted in one of a number of holes 59 in the lever. In modifications, Figs. 6 and 7 (not shown), the pawl is replaced by an abutment and the ratchet by a second abutment slidable on the lever 12 and adjustable by screw and nut mechanism to determine the maximum opening of the valve. The spring 9 may be replaced by a collar 56<SP>1</SP> or pin 57, see Figs. 12 and 13 (not shown), the resilience of the lever 9<SP>1</SP> being sufficient to allow yielding movement of the rotary. disc. In further modifications the initial movement of the rotary disc when an obstruction is encountered is utilized to operate the lever 91 automatically. As shown in Fig. 8, an arm 69 mounted on a collar 31 secured to the handwheel 2 carries a push rod 70 which, on endwise movement of the shaft and rod 3, rotates a pivoted plate 71<SP>1</SP> connected by a link 73 to a similar plate 74 bearing against the lever 9<SP>1</SP>. The push rod is slidable in a collar on the lever so that it moves to the right as the lever is swung clear of the member 11. In Fig. 9 the lefthand end of the shaft bears against a screw carried by a pivoted plate 87 connected by a link 86 passing through the hopper A to a pivoted plate 82 bearing against the lever 9<SP>1</SP>. The discharge outlet 21 for ground material, see Fig. 11, may be fitted with a gate valve 76 which is closed automatically when the lever 9<SP>1</SP> is operated to prevent discharge of foreign bodies. This valve is normally maintained open by engagement of the rounded end of a member 81 on the lever with the downturned end 78 of a transverse rod 77 secured to the valve, the movement of the lever causing the member 81 to swing clear and allow the valve to drop. The ground material is thus diverted through an aperture 82 and as the feed is shut off by closure of the valve 4, the valve 76 swings to a rinsed position determined by an abutment 83. The pulley F serves as a reservoir for lubricating oil which is agitated by paddles, 3.7 .secured to the shaft.