Patent GB-142989-A (GB)
Title: Improvements in separators for grading crushed rock and other materials
IPC: B07B1/34
Filed: 1919-04-09
Abstract: 142,989. Sturtevant, T. J. April 9, 1919. Fixed sieves.-A separator for grading crushed rock, minerals, bone fertilizer, &c. comprises superposed screens carried by a removable frame provided with bridge bars to which vibrations are imparted through pins by means of hammers. The separator comprises units each having a casing 5, 7 with a hinged cover 9 thereon and supported in an inclined position by a framework 17, 19 and supplied with material to be graded by a feed-box 21 containing a screw conveyer 23. The separator contains three screens, the uppermost being the scalper screen comprising a clothing 39 secured to a frame formed by end and side angle-bars 41, 43 and transverse bars 45, carried by the cover by means of hanger-plates 47 with flanges 49 on which the screen may be slid; the screen is held in position by means of resilient locking-arms 51 provided on the hanger-plates and adapted to engage the bar 41. The intermediate and fine screens each comprise clothing 53 secured at the sides, the upper and lower ends being left free, between wooden or other bars 55 and angle-bars 57 having flanges 59 secured to a master frame comprising side plates 61 with lower inturned flanges 63 connected by bars 65 and upper inturned flanges 67 connected by bridge bars 69 of wood &c. The screens are detachably secured to the master frame by means of bolts 79, whereby the clothing also may be tensioned, and to prevent material from entering the spaces between the bars 55 and the plates 61, the flanges 59 are arranged to engage the flanges 63, 67; deflecting-plates 71 similarly prevent material from the scalper screen from entering between the plates 61 and the casting. The master frame is yieldingly mounted in the casing on springs 81 secured to bars 83 resting on the bottom of the casing, and brackets 85 are provided to prevent downward sliding of the frame. The screens are vibrated by means of pins 93 projecting through collars 95 on the cover, through sleeves 97 on the scalper screen, and having tapered ends frictionally secured in split sockets 99 secured to the bridge bars. Cotters 101 are passed through the pins, so that on lifting the cover, the pins are lifted upwards therewith. The pins receive blows from hammers 103 secured to preferably resilient arms 105 carried by flat bars 107, fulcrumed in open bearings in brackets 111 secured to the cover, and held in position by gravity. Pins 115 may also be provided mounted close to some of the pins 93 with their ends in split sockets 117 on the scalper screen formed on the plates 119 carry ing the sleeves 97. Hammers 121 are provided for the pins 115 made integral with U-shaped members 123 carried by preferably resilient arms 125 secured at their other ends to the fulcrum bars 107. The hammers are lifted and dropped to strike the pins by means of rotary cams having fingers 127 adapted to engage the hammer arms and carried by shafts 131 mounted in bearings on the cover and rotated by pulleys 135 from a pulley 139 on one of the shafts driven by a belt 141 from the conveyer shaft 24. When several units are employed side by side in the separator, in order that the drive for the alined cam shafts 131 may be transmitted from one unit to the next, the shafts have formed on their adjacent ends couplings comprising flanges with lugs thereon so formed as to permit of the cover of any unit being lifted, whilst when the shafts are in line, the lugs engage. In a modified method of mounting the clothing of the screens in the master frame, Fig. 19, the.clothing is secured at its edges to bars 225 connected by bolts 227 to the frame, and a bar 229 is provided between the bridge bar 231 and the upper screen clothing. A channel stretching-device 233 is provided between the upper and lower clothings, and the stretching- device and the bar 229 are secured to each other and to the bridge bar, whereby the vibrations are transmitted to the lower screen. Other modifications are described similar to that shown in Fig. 19, such modifications being also described as applied to the construction in which only one screen clothing is employed in the master frame.