Patent GB-799612-A (GB)
Title: Improvements in machines for cutting veneer strips into lengths
IPC: B23D33/00
Filed: 1956-03-05
Abstract: 799,612. Feeding webs. MULLER, C. H. March 5, 1956 [March 18, 19551, No. 6876/56. Addition to 767,228. Class 100(1) [Also in Group XXIII] An improvement in the apparatus for automatically controlling veneer shears as claimed in the parent Specification, comprises conveying means for the veneer strip, a first drive means for the conveying means adapted to assume a comparatively high speed and a comparatively low speed, a second drive means for the shears switching means connecting the second drive means to the shears, and a control device responsive to a predetermined length of strip measured beyond the shears for reducing the speed of the first drive means, to operate the switching means for causing the shears to perform one operation, then to increase the speed of the first drive means and to repeat this cycle of operations. As shown, a strip of veneer A is fed by an endless conveyer 3 beneath a cutter 1 driven bv a motor 2 preferably as described in Specification 742,033 [Group XXIII]. The conveyer 3 is driven through a chain or belt drive R by a conveyer 4 driven alternatively by a variable speed motor 5 or a motor 7. Electric contacts 9, 9' control the actuation of the motor 2, while contacts 8, 8<SP>1</SP> control the actuation of an electro-magnetic clutch 26, 27. The clutch 26, 27 is carried by a shaft driving the conveyers 3, 4 and permits driving the conveyers at high speed through the. part 26 by the motor 5 or at low speed through the part 27 by the motor 7. The contacts 8<SP>1</SP>, 9<SP>1</SP> are adjustable along a support T<SP>1</SP>, thus permitting cutting of various lengths of veneer A as determined by the position of the contacts 8<SP>1</SP>, 9<SP>1</SP>. A selector switch 20 determines which pair of contacts 8, 9 or 8<SP>1</SP>, 9<SP>1</SP> are operative. In operation, the clutch 26 is energized by a battery 32, Fig. 3 through a lead 70, the contact 40 of a relay 38 and a wire 60, thus the conveyers 3, 4 are driven at high speed. When the front end of the veneer A engages the contact 8 current flows from a battery 34, through a lead 49, the frame 6 carrying the cutter, the veneer A, the contact 8, the lead 64, the switch 20, and a lead 65 to the grid 46 of a triode 30 thereby causing current to flow from the battery 34 through the lead 50, contact 42 of a relay 41, a lead 68, the winding of the relay 38, the lead 69, through the triode 30 to the lead 48 connected to the battery 34. The relay 38 is thus energized to actuate contact 40 which de-energizes the clutch 26 and energizes the clutch 27, such that the conveyers 3 and 4 are driven at low speed. When the front end of the veneer A engages the contact 9, current flows from the battery 34 through the lead 49, the frame 6, the veneer, the contact 9, the wire 72, the switch 20, and a lead 73 to the grid 47 of a triode 31, thus varying the grid bias, such that current flows from the battery 34 through the lead 50, contact 39 of the relay 38, lead 74, the winding of the relay 41, lead 75, through the triode 31 and leads 67 and 48 to the battery 34. The relay 41 is thus energized to close contact 43 which supplies current from a supply N to the motor 2 to actuate the cutter 1. Energization of the relay 41 opens contacts 42 thereby breaking the circuit to the plate 51 of the triode 30. The relay 38 is de-energized after a delay dependent upon the discharge time of a capacitance 37. The conveyer 4 is driven faster than the conveyer 3, such that the piece B cut from the veneer A is spaced therefrom, thus interrupting the currents flowing from the battery 34 until the front edge of the veneer A meets the contact 8 and the cycle of operation is repeated. Meanwhile the conveyers 3 and 4 are driven at high speed. The veneer A actuates the contacts 8<SP>1</SP>, 9' in the same manner as the contacts 8<SP>1</SP>, 9'; the contacts 8<SP>1</SP>, 9<SP>1</SP> are rendered operative by actuation of the selector switch 20 to the appropriate position.