1,014,673. Bookbinding. R. D. H. THOMPSON & CO. Ltd. Feb. 25, 1963 [Nov. 23, 1961], No. 7557/63. Divided out of 1,014,671. Heading B6A. Apparatus for pressing or nipping books comprises two pressure plates relatively movable towards and away from each other, an hydraulic cylinder containing hydraulic fluid, linked to one of said pressure plates whereby a pressure proportional to the pressure between the pressure plates is applied to the hydraulic fluid, and means for governing the maximum pressure of the hydraulic fluid and hence the maximum pressure between the pressure plates. Apparatus for nipping the spine of a book comprises two pressure plates 3, each carried by two links 5 pivoted to the machine frame at 8 and moved by means of levers 10 rotatable about shafts 11, 11a. The levers are pivoted at their upper ends to rearwardly directed extensions 19 of the pressure plates and at their lower ends to pistonrods 21. The pistons 15 move in cylinders 16 containing an hydraulic fluid such as oil. The cylinders are formed with end bearings 20 cooperating with a driven crank-shaft. Rotation of the crank-shaft moves the pressure plates towards and away from each other. Each cylinder is provided with a relief valve which permits the oil contained in the cylinder to escape should the pressure between the pressure plates exceed a preselected value. The shafts 11, 11a are carried by threaded blocks 13, either of which may be moved by rotating its respective housing 14 by means of a hand wheel 18, to adjust the initial spacing between the pressure plates. Each pressure plate is provided with a rotatable jaw 31 urged towards the position shown in Fig. 2 by a spring-biased pin 32 bearing against a forked lever 34 screwed into the jaw. The two arms of the forked lever engage each side of an upstanding projection 35 on the pin 32. In operation, the jaws initially apply pressure along a line spaced from the edge of the spine and as the pressure increases the jaws rotate to apply pressure along a marginal strip adjacent the spine of the book. The spinenipping operation may serve to expel the air and partially compress the thread between the pages of the book, whereupon the book is passed to a second pair of pressure plates to complete the nipping operation. Apparatus for applying pressure over the entire surface of a book consists of a fixed jaw 41 and movable jaw 42. The latter is supported by two pairs of levers 51, 52 (only one pair being shown in Fig. 3) pivoted on shafts 53, 54 and interconnected by ties 55. A toggle 58 is provided having one arm 60 mounted on a crank-shaft 62, a second arm 57 pivoted to the lever 51 and a third arm 63 pivoted to a member 66. One end of the member 66 is pivoted at 65 to the machine frame and the other end is pivoted to a piston 67 movable in a cylinder 68. Initially, the cylinder is connected to source of hydraulic fluid at low pressure. Rotation of the crank-shaft 62 moves the arm 60 downwardly to pivot the levers 51, 52 in a clockwise direction and close the jaws 41, 42. The pressure between the jaws is transmitted via the arms 57, 63 to the oil in the cylinder and should it exceed a predetermined value a relief valve in the low pressure line blows and any further downward movement of the arm 60 is taken up by movement of the piston in the cylinder. When the arms 57, 63 assume a substantially straight line, the cylinder is connected to a source of hydraulic fluid at high pressure to effect full nipping pressure. The high pressure line likewise incorporates a relief valve which governs the maximum nipping pressure. The position of the jaw 41 may be adjusted initially by rotation of a screwthreaded housing 46 by means of a gear chain 49 and hand wheel 48. Each jaw may be provided with a countersunk button behind which is a connection to a source of compressed air. The button lies flush with the jaw during the nipping operation and is blown away from the jaw after the nipping operation to permit the compressed air to escape and prevent the book sticking to the jaw. The books are conveyed past the pressure plates 3 by pairs of gripper plates on endless chains. After being released from the gripper plates, the books are pushed by bars on an endless chain to the jaws 41, 42. The bars move below the level of said jaws. Alternatively, the books are conveyed past both stations by a pair of endless belts.