Patent GB-351134-A (GB)
Title: Improvements relating to slicing machines
IPC: B26D7/24
Filed: 1930-04-09
Abstract: 351,134. Guards for slicing- machines. BERKEL & PARNALL'S SLICING MANUFACTURING CO., Ltd. and THOMAS, H., Aden Road, Ponders End, Middlesex. April 9, 1930, No. 11304. [Class 80 (iv).] A slicing-machine has a guard which, in the effective position, prevents access to the knife, and is associated with means ensuring that the knife must come to rest before or immediately the guard is moved into an ineffective position. As shown in Fig. 2, the invention is applied to a machine having a disc knife mounted on an axis which moves in an orbital path and is enclosed in a knife casing F having an opening in its lower part through which the bread is fed. The loaf is supported on a surface E.and the cut slices are deposited on a receiving plate at the other side of the casing F. The surface E and the receiving plate are each covered by a guard consisting of an assemblage of horizontal bars, the bars forming the fronts of the guards being formed as a pivoted door unit. The slice receiver and its guard are bodily displaceable to prevent fouling by the grinding handle. The slice receiver guard front is hinged similarly to the front of the guard 1 which is carried by a rotatable bar 1a. A V-shaped member 14a, 14b straddles the casing F, is pivoted on a bracket 15, and is actuated by a compression spring 17. The free ends are slotted to engage, at each side, with a pin 16, one pin being on each guard door. The strength of the spring 17 is such that, if either door is raised manually, the other is raised by the spring, but the spring cannot lift both doors. The bar 1a is connected, as shown in Fig. 3, by a crank 21 to a rod 22 pivoted to an arm on the shaft 24 which is thus oscillated as the front of the guard 1 is swung. The shaft 24 carries a lever 26 having a pin and slot connection 31 with a double lever 29, 30 loose on the shaft 24. The brake shoe 20 is carried on a rod 33 extending from the arm 29, and acts on the rim of the flywheel K against which it is pressed by a spring 28 interposed between the shoe and the portion 26a of the lever 26. A pin 35 is projected out of the shoe into a hole 36 in the flywheel, the shock of the sudden retardation being taken by the shoe sliding against the spring on the rod 33. In a modification, the pin 35 is dispensed with and the shoe is urged against the flywheel by a torsion spring coiled on the hub of the lever 29. The lever 26 has a downward extension 27 which is connected by a telescopic and resiliently extensible rod 32 with the motor switch J. The lifting of either guard door thus switches off the motor and brakes the flywheel. This is effected mechanically in the apparatus described above, but it may be effected electromagnetically, e.g. a switch in the motor circuit may be associated with a lowvoltage electromagnetic device which holds the switch " on " and holds a brake clear of the flywheel so long as the guards are closed. The circuit of the electromagnetic device includes either or both doors of the guards, or a part thereon (in which case the door or part would be insulated) and the circuit would be closed only when the door rests on a contact. When the door is opened and the circuit broken, the switch is moved to the " off " position and the brake is applied. In a further modification, the opening of the slice receiver guard automatically puts a supplementary motor switch into the " off " position, and the slice receiver and guard are bodily removable, to prevent interfering with the grinding-handle when it is in use, by a preliminary lifting motion which also puts " off " the said switch. To prevent the switch from being accidentally put " on," a swinging catch is released by the removal of the slice receiver and locks the levers connected with the switch. A similar supplementary switch may be associated with the door of the loaf-support guard. Fig. 11 shows the application to a handdriven machine. The door 71 of the loaf support guard is hinged at 72 and has a projection 75 which engages a curved groove 74 in a disc 73 on the main shaft R when the handwheel Q is brought to a certain position and the door is raised. The groove may have a movable stop at its open end to prevent accidental entry of the pin 75. The door of the guard may be rigidly connected with a guard for the slice receiver at the other side of the knife housing. The guards described above may be associated with audible alarms which are operated when a guard is opened, and the guards may actuate a belt-shifter or clutch to disconnect the knife when a guard is opened. The invention is also applicable to swinging knife machines.