Patent GB-713802-A (GB)
Title: Machine useful in the manufacture of venetian blinds
Inventor: VODRA RICHARD JAMES
IPC: E06B9/266
Filed: 1952-02-15
Abstract: 713,802. Venetian blind manufacture. LEVOLOR LORENTZEN, Inc. Feb. 15, 1952, No. 4084/52. Class 20 (3) A machine for assembling Venetian blinds by inserting slats into two or more spaced aligned ladder tapes, has means for suspending at least two ladder tapes with the corresponding longitudinal tapes thereof lying generally in common planes and the cross tapes generally horizontal, means for spreading the longitudinal tapes of each ladder tape between two adjacent cross tapes and slat inserting means for moving a slat endwise along a fixed path into inserted position between the spread portions of the tapes. The machine may also comprise means for punching lift cord rout holes in and severing the slats during insertion and means for threading the lift cord through the holes. Slat insertion.-The slat insertion and cord threading portion 20 of the machine comprises a framework including a pair of uprights 22 braced by cables 23 and a pair of horizontal guide members 24 in front of the uprights. A carriage 25, positioned above the guide members 24, is mounted for vertical movement on the uprights 22 by means of endless link chains 26 secured to each end of the carriage and mounted on the upright 22 by a drive sprocket 27 and idler sprockets 29, the lower sprocket 29 being movable to take up slack in the chain 26. The drive sprockets 27 are mounted on a longitudinal shaft 30 intermittently rotated from an electric motor 31 through a clutch 121, and brake 120, mechanism (Fig. 13) to move the carriage 25 up or down between the uprights 22. Ladder tapes, secured to a Venetian blind head bar comprising a sheet metal channel, are suspended from a pair of shelf-like hooks 32 mounted on the carriage 25. At one end of the guide members 24 (Figs. 1 and 5) a slat driving roller 35 is mounted on a shaft 36 continuously driven from an electric motor 37 through a belt 39, the roller 35 frictionally engaging a slat (or slat stock) to move it through a gate assembly 34 in a path above the members 24. A friction type slip clutch built into the hub of roller 35 causes the roller to stop when the slat is stopped by the gate assembly 34 or other stops. The assembly 34 comprises a C-shaped gate 40 freely pivotally mounted by its lowermost portion on a shaft 41. The gate 40 is supported by a frame and is biased to the closed position by a spring 44 and can be opened manually to set the machine in operation by a rod 45 and thereafter by energization of a solenoid 46. At the opposite end of the guide members 24 a stop 47 is mounted in the path of the slat on a carriage 49 slidable along the guide members 24 and having a pointer 62 co-operating with a scale 61 to indicate distance from the gate assembly 34 for varying sizes of blinds being assembled. Tape spreader units 50, one for each ladder tape, are each mounted on a carriage 51 movable along the guide members 24 and having a pointer 62, each unit 50 comprising an air manifold 52 having spaced, opposed, generally convex intakes 54 and connected to a blower 55 by a suction hose 56 to draw air in through the intakes 54. Flareguides 57 facilitate entry of a slat between the intakes 54 and a pair of spring members 59 is mounted on the carriage 51 and inclined at the slat entry end to retain the slat against deflection upwardly. A series of intermediate supports 60 are provided for the slat. When the slat is fully inserted it contacts a feeler 65 adjacent stop 47 to complete a circuit through a microswitch 64 mounted on the carriage 49 to cause the motor 31 to elevate the carriage 25 with the ladder tapes and inserted slat until the slat contacts the feeler '66 of a microswitch 67 also on carriage 49 to complete a circuit to stop the raising, the feelers being arranged so that for each slat, the carriage 25 and ladder tapes are raised an amount equal to the distance between adjacent cross tapes. This operation continues until the required number of slats, with or without an extra one to be used in the bottom bar assembly, have been inserted and the carriage 25 then rises (the microswitch 67 not being actuated by the additional slat which is not raised) until a high limit switch 69 on an upright 22 is actuated to stop the carriage. Slat cutting and punching.-The slat cutting and punching portion 21, Figs. 1 and 9, comprises a coil holder 71 for metal slat stock which is, if flat, fed between a series of forming or bending rolls 72, and is then fed through rubber covered feed rollers 74 to punching dies 75, 75 and cutting dies 76 situated therebetween so that at each operation the left-hand rout hole is punched in the severed slat and also a hole in the stock which forms the right-hand hole of the next slat. The dies 75, 76 are operated by aligned camshafts 77, 79, the shaft 77 being rocked by an electric motor 80 to operate the right-hand die only, when it is required to form additional intermediate lift cord holes, and a disconnect mechanism 81 is provided to connect the camshaft 79 for operation with the shaft 77, the two being normally connected. Rocking of the shafts 77, 79 is controlled by a stop 82 (Fig. 4) mounted on a carriage 84 movable along the guide members 24 and set against a scale 87 measured from the cutting die 76, the stop 82 being moved slightly before stopping the entering slat to actuate a microswitch 85 thereon to complete an electrical circuit through the motor 80. Operation of shafts 77, 79 also, by means of a lever 115 (Fig. 13), rocks the sha't 41, which is of square cross section, on which stop 82 is mounted, the stop 82 thus being oscillated out of the path of the slat as it is severed and the severed slat is moved forwardly by the roller 35, the feed by the roller 35 being faster than that of the stock by rollers 74 so as to leave a gap for the gate 40 to close while the carriage 25 is being raised. For wide blinds, where additional ladder tapes and cords are used, for each additional tape and cord, a spreader unit 50 is provided and a stop 106 and microswitch 197 similar to stop 82 and switch 85, the stop 106 however also operating a solenoid 105 to operate the disconnect mechanism 81 before operating the motor 80 to cause a hole to be punched for the cord. Lift cord threading.-Stringing needles 89, having a tapered end and hollowed out channel 90 to clamp a cord, are provided for inserting the cords through the holes as the blind is assembled. Each needle is mounted by roller mountings 94 on a carriage 92 extending over the carriage 25 and each needle is received in an alignment guide 95 slidable on the carriage 25. The carriage 92 is mounted for vertical movement between the uprights 22 by means of a pair of endless cables 96 running round idler pulleys 97 and drive pulleys 99 which are mounted on a shaft 100 driven by a reversible electric motor 101 and speed reducing unit 102. In the assembly of a blind, with the carriage 25 in the lowermost position, the carriage 92 is raised till the needles 89 are above the head bar, the cords inserted and the needles lowered till the ends have passed through the head bar and lie just above the path of a slat during insertion. The needles remain stationary while the ladder tapes and inserted slats are raised, the cord then being secured to the bottom bar. When more than two holes are provided, the same cord may be used for two sets of holes, the cord passing through one set as described and then either through the second set by a hand stringing needle or secured to a second needle 89 as the blind and carriage 25 is lowered, so that the cord is passed through the second set and is then secured to the head bar. Operation.-Hand operated switches 109, 110, 111, a switch. not shown, and switch 126 are used respectively to start the motor for the blower 55, the motor 31 for carriage 25, motor 37 for the roller 35, motor 80 for the slat cutting and punching device, all of which are operated continuously and motor 101 for the carriage 92. A motor (not shown), for feed rolls 74, operates continuously and a motor, not shown, for the slat forming rollers 72 is operated continuously except when interrupted by a microswitch 104 operated by accumulation of excessive slack between the rolls 72 and rolls 74. To start operation of the machine, the carriages 25 and 92 being in the lowermost positions, the motors are switched in with switch 110 in up position, and the slat stock fed by rolls 74 rests against the gate 40. The gate 40 is manually opened by the rod 45 and the machine then operating automatically in the following sequence:-at stop 82, microswitch 85 energizes relay 112 to clutch operating solenoid 114 to cause single rotation of a clutch to rock camshafts 77 and 79 to cut and punch the slat and rock shaft 41 to oscillate stop 82 and de-energize relay 112, the severed slat being fed by roller 35 till end stop 47 is reached, feeler 65 of microswitch 64 being operated to energize a relay 116. providing the microswitch 117 has been operated by closing of the gate 40, which is as the end of the severed slat passes it. Relav 116 operates switch 119 to release a brake 120 and complete a circuit to an electromagnetic clutch 121 between motor 31 and shaft 30, so as to raise carriage 25 until the inserted slat contacts feeler 66 to actuate microswitch 67 which energizes relay 122 to complete a circuit through, switch 124 to solenoid 46 to open gate and restart the cycle and at the same time to raise the movable contact of a switch 125 to de-energize relay 116 and restore switch 119 to normal position with the circuit closed through brake 120. Contacting of stop 82 by succeeding slats not only energizes relay 112 but opens the circuit through microswitch 82 and relay 122 to open switches 124, 125 to de-energize the solenoid 46 to release gate 40 which rests on the top of the slat. When the additional last slat has operated microswitch 64, the carriage 25 will continue to rise without the