273,577. Clark, E. W., and Schramm, C. Dec. 13, 1926. Sheet-separators; sheet guides and smoothers.-In a machine for making book cases or covers, cloth covers are fed from a stack by oscillating pneumatic separators which grasp the front edge of a cover and carry it into a position to be grasped by the fingers of a rotating receiving-cylinder, which .carries the cover around in contact with a glueing-roller, an edge levelling- bar being oscillated independently to hold the edge of the cover fiat on the cylinder until it is gripped. Feeler devices are provided for stopping the machine in the event of a cover not being fed to the receiving-cylinder. A cam-shaft 2, Fig. 5, geared to a shaft 8 which is connected to a driving pulley 9 by a clutch 10, carries a cam 11 which engages a rocking lever 12, a segmental rack 13 being provided on the upper end of the lever 12 to engage a pinion 14 .on the shalt of the sheet receiving cylinder 16. A pinion 17 on the other end of the cylinder engages a pinion driving the glueing-roller, the glue reservoir being heated in known manner. Pinions 23 at each end of the cylinder shaft are geared to pulleys 25 driving endless belts 26 which are connected to a sliding carriage 27, Fig. 13, provided with fingers 270, 271 to grip the edge of a glued sheet and convey it over a folding- table. Suction cups 49, Fig. 10, are mounted in blocks 47 on arms 46 which are adjustably secured upon a transverse bar 45 supported at its ends by arms 44, the latter being loosely mounted upon a tubular shaft 32. Tubular nipples radiating from the shaft 32 are connected by flexible tubes 52 to the suction cups 49, one end of the shaft being connected to a suction pump. An oscillatory to-and-fro movement is given to the shaft 32 by bell-crank levers 30, Fig. 1, connected by links 33 to bell-crank levers 34 which are rocked by cams 36 on a shaft 37 geared to the pinion 4. The shaft 37 also carries a cam which oscillates a lever controlling a rotary valve in the suction device. The to-and-fro movement of the suckers is accompanied by a vertical movement, in which the suckers are brought down upon the top sheet and then lifted, a downward movement being given when they are over the receiving-cylinder. The vertical movement is produced by providing on one of the arms 44 a lateral arm 62, Fig. 1, through which passes a vertical rod 63 connected at its lower end to a two-armed rocking lever 66, 67 engaging a cam 68 on the shaft 37, the connection between the members 62, 63 being cushioned by a spring 64. The levelling-bar 71, which levels the edge of the cover upon the receiving-cylinder so that it is readily gripped by the fingers 61, is supported on arms 70 mounted freely upon the shaft 32, and is normally held in a raised position by springs 72 connected between it and fingers 73 clamped on the shaft 32. When the shaft 32, together with the bar 45 and levelling-bar 71, are swung over to apply a sheet to the cylinder 16, the bar 71 is pushed down upon the sheet by rollers 74 on its ends abutting against a cam 75 fixed upon the machine frame, the bar being lifted by the .springs 72 on its return movement. Pile tables and support.-The table 78 carrving the cover sheets 77 is provided with front and side positioning-guides, and the front corners of the sheets are held beneath resilient retaining- fingers which can be adjusted for sheets of different widths. Screwed shafts engaging the sides of the table are rotated intermittently to raise the table as sheets are removed, the lower ends of the shafts being provided with worm gears engaging a pinion shaft 95, Fig. 1, which is geared to a ratchet wheel 99 controlled by a pawl 100. The pawl is mounted on a pivoted plate 1021 provided with a projecting pin 111 engaging within a slot in a link 113 connected to the rocking arm 30. Movement of the table is prevented until the pile is reduced to a predetermined height, by a rod 104 engaging the pivoted plate 102, the slotted link then riding idly over the pin 111, until the rod 104 being lifted, the plate 102 is released and is pulled round by a spring until the pin 111 abuts against the end of the slot 112 and subsequently moves the link 113. Tripping-arrangements.-The clutch 10. Fig. 5, connecting the main shaft to the driving- pulley is controlled by a treadle 123 provided with an electromagnetic trip 125, 128 which stops the machine if the separators fail to deliver a sheet to the receiving-cylinder 16, Fig. 13, or if the fingers 270, 271 of the sliding carrier 27 fail to grip a gummed sheet. For this purpose feelers 136', 137 in the form of spring-pressed plungers are mounted upon the sheet-levelling bar 71 so that the plungers 137 make contact with the receiving-cylinder 16 when the bar is in its forward position, circuit then being made through plunger 136 and a conducting block 130 against which it abuts, and actuating the tripping-mechanism. Similarly the absence of a sheet between the fingers 270, 271 on the carrier 27 causes current to pass between them and through an arm 140 which makes contact with the brushes 138 on the block 130.