Patent GB-108868-A (GB)
Title: Improved Bed Movement for Cylinder Printing Machines.
Inventor: JOHNSTON THOMAS RUDDIMAN
IPC: B41F3/58
Filed: 1916-04-03
Abstract: 108,868. Johnston, T. R. April 3, 1916. Bed-reciprocating apparatus; tripping-arrangements.-The type-bed of a cylinder printing- machine having a continuously-revolving impression cylinder is driven in the printing direction by gearing from the impression cylinder engaging racks on the bed, and in the opposite direction by continuously-revolving wheels engaging other racks on the bed, the racks being brought into gear with their respective wheels by means oi one or more cams. In the form shown in Figs. 1 and 3, the impression cylinder a<1> supported on side frames b<1> and continuously rotated by gearing a<5>, g<7>, g<6>, g<5>, from a gear g<1> on the main driving-shaft is provided at each end with a gear a<2> which engages intermittently with a rack c<4> on the forme bed c'. These gears a<2> drive the bed in the printing direction. The return stroke of the bed is effected by gears e<1>, driven continuously by a gear e<4> from the gear g', engaging racks c<8> on the bed. When the bed reaches the end of its printing stroke, the impression cylinder a<1> and the gears g<7>, e<1> and e<4> are automatically raised by wedge boxes h<2> moved by a shaft h<1> to cause their wedges h<3>, h<4> to act on wedgea h<5> on the bars h<6> attached to the cylinder bearings, bringing the gears e<1> into the path of the racks c<8>. The reversal of the bed is effected by cams as follows. Carried by the underside of the bed is a runner c<3> adapted to enter a cam-groove d<3>, Fig. 3, in a constantly rotating disk d<1>. This cam is so designed that it allows the runner c<3>, until it is firmly locked in the cam and until the wheels are out of gear with their racks, to travel at the same speed as that of the surface of the cylinder. The cam-disk d<1> is carried on a cross frame member d<6> and is driven bv gearing d<8>, d<10>, d<11> from a gear g<8> on the main driving-shaft. A sprocket-wheel d<12> on the axle of the disk d<1> is connected by chain d<13> or by other gearing to a similar cam-disk at the other end of the machine. Whilst at either end of its travel, the forme bed is held and operated only by the cam. The gear-wheels g<6>, g<7> are always in full gear with each other whether the cylinder a<1> is raised or lowered. The cross-frame b<3> has a small recess in it to permit the passage of the runner c<3>. In a modification, the cam-disks are mounted vertically. Four cams may be used in place of two, which operate two runners arranged at the sides. Fig. 6 shows a modification in which the length of the period of control by the cams can be made of any desired extent. The small shaft k<12> on the bed is connected indirectly to a runner k<7>, which travels in the cam-slot k<2> in the camdisk k<1> arranged vertically, by an oscillating arm k<5> pivoted at k<8> to the side frame, and which has a side arm k<6> which carries the runner k<7>. The shaft k<12> enters a recess in the upper end of the arm k<5> and is retained therein by a pivoted arm k<13>, which is actuated by riding upon a cam-surface k<15>. When the bed is reversed, the shaft k<12> is released by the arm k<13> striking against a curved stop k<16>. A similar device k<17> on the other side of the machine is operatively connected by an arm k<10> to an extension k<9> of a pivoted arm k<5>. By redesigning the cam-groove k<2> and the sizes of the levers k<5>, k<6>, the starting movements of the forme bed can be varied. In this form, the cross-frame b<3> has no break in its surface. Two or four cams k<1> may be used in this modification. Pneumatic buffers may be used to check the momentum of the forme bed.. The invention is stated to be applicable to machines having more than one forme and one cylinder.