PRESS PLATENS.
A drive system for the cutting station in a platen press has four toggle joints supporting the platen and each having a cam follower for moving the toggle joint by an associated rotating cam. The four toggle joints are disposed in pairs perpendicularly to the transport direction of sheets in the press. The pairs of toggle joints are aligned, with one pair of toggle joints being disposed between the other pair. The toggle joints are connected to a release device controlled by a security coupling. The cams are mounted on a common shaft provided at one end with a braking mechanism. Declutching of the security coupling simultaneously commands operation of each release device and of the braking mechanism. 1. In a platen press having a cutting station including a lower movable platen and an upper fixed platen, and a gripper bar means for transporting sheets through said press, a drive means for actuating said lower platen comprising: four toggle joints interconnected between said lower platen and a fixed frame of said cutting station, said toggle joints being disposed in pairs and each pair of toggle joints being aligned on an axis perpendicular to the direction of sheet transport through said cutting station and one pair of toggle joints being disposed between the other pair, each toggle joint having two arms respectively connected by swivel means to said lower platen and said frame and having an axle pivotably connecting said arms; a driveshaft connected to a drive means; a camshaft in driving connection with said driveshaft carrying four cams thereon; four cam followers respectively engaging said four cams, said four cam followers being respectively mounted on said axles of said four toggle joints for inclining said lower platen relative to said upper platen; four compression springs respectively interconnected between said frame and said toggle joints for urging said cam followers against said cams; pulling means interconnected between said frame and said lower platen for urging said lower platen toward said frame in opposition to movement of said lower platen imparted by said toggle joints; two toggle joint release means contained in said frame each having a bearing receiving one of said swivel means of the toggle joints in one of said pairs of toggle joints for immediately retracting said one pair of toggle joints upon actuation of said toggle joint release means such that said pulling means pulls one end of said lower platen toward said frame; a brake means operable on said driveshaft for automatic braking thereof; and a hydraulic control means in hydraulic connection with said toggle joint release means and said brake means for simultaneous actuation thereof. 2. A drive means as claimed in claim 1 wherein each of said toggle joint release means comprises: a piston rod connected to said bearing and extending through a channel in said frame and terminating in a piston head; a yoke connected to said frame in communication with said channel, said yoke having a chamber receiving said piston head, said channel and said chamber in said yoke being in hydraulic connection with said hydraulic control means. 3. A drive means as claimed in claim 1 wherein said pulling means comprises: a plurality of cups each having an open end connected to said frame; a rod having a free end terminating in a stop and having an opposite end connected to a bottom of said cup; and a connection means swivelably connected to said lower platen and connected to said rod at said bottom of said cup. 4. A drive means as claimed in claim 1 wherein said brake means comprises: a disc carried on said driveshaft; and a hydraulic clamping means partially surrounding said disc and connected to said hydraulic control means for clamping said disc and thereby stopping rotation of said driveshaft upon actuation thereof. 5. A drive means as claimed in claim 1 wherein said hydraulic control means includes a means for detecting overload of said transporting means and wherein said hydraulic control means immediately actuates said brake means and said toggle joint release means upon detection of said overload. 6. A drive means as claimed in claim 5 wherein said means for detecting said overload is an elastic coupling interconnected between said transporting means and a valve in said hydraulic control means, said elastic coupling being released upon the occurrence of an overload and actuating said valve. 7. A drive means as claimed in claim 5 wherein said hydraulic control means includes means for actuating said brake means independently of actuation of said toggle joint release means for normal stopping of said press. 8. A drive means as claimed in claim 2 wherein said yoke has a surface having a circular channel therein communicating with the atmosphere through a conduit in said yoke, said channel being covered by said piston head and permitting draining of hydraulic fluid from said chamber after actuation of said toggle joint release means. 9. A drive means as claimed in claim 8 further comprising a means for supplying compressed air to said channel for aiding in draining said hydraulic fluid. 10. A drive means as claimed in claim 2 further comprising a pilot valve in hydraulic communication with said chamber and actuated by said hydraulic control means for releasing hydraulic pressure in said chamber after actuation of said toggle joint release means for returning said toggle joint release means to an unactuated position. 11. A drive means as claimed in claim 1 wherein said driveshaft is connected to said camshaft by a worm carried by said driveshaft engaging a worm gear mounted on said camshaft.
