Patent GB-259280-A (GB)
Abstract: 259,280. Whyte, T. G., and Smith, T., (trading as Whyte Smith). July 1, 1925. Screw-and-nut mechanism.-In means for obtaining combined rotary and axial reciprocating motion, applicable to pattern producing mechanism of circular knitting machines, the hub of the rotary member has threaded engagement with a worm or screw which is rotated at a faster rate than the hub to obtain motion in one direction and is held stationary to effect the return movemen, the action being controlled by a clutch and a brake thrown' alternately into and out of engagement by the hub member in its movements. A drum 6, Fig. 1, which may be tha pattern producing drum of a circular kniting machine, is carried by a hub 4 engaging a threaded portion 3 of a sleeve 2 enclosing a rod 1, the drum being rotated by a gearwheel 8 loosely mounted on a loose collar 9 and carrying a number of rods 7 passing through holes in the spokes 5. A gear-wheel 10 driving the wheel 8, carries a larger gear 11 meshing with a pinion 12. secured to the collar 9, so that the gear ratio 11, 12 is greater than that of the gears 10, 8. When the sleeve 2 is clutched to the gear 12, it is rotated faster than the hub and carries the drum axially in one direction, the return movement being obtained by disconnecting the sleeve from the gear 12 and locking it to a fixed part 32 of the machine. The controlling parts are carried by the rod 1 movable axially within the sleeve 2, and comprise a clutch collar 28 with teeth 28<a> adapted to engage recesses 31 in the collar 9, and a similar collar 33 with teeth 33<a> adapted to engage recesses 35 in the machine frame 32. Also secured to the rod 1 by bolts 16, 22 are collars 15, 21, between which and the ends of the threaded portion 3 are interposed springs 27, 25 with or without washers 26. The collars 15, 21 carry in lateral slots such as 18, loose radial pins 19, 24 projecting inwardly into bayonet slots 17, 23 in the sleeve 2 through which the bolts 16, 22 pass, spring such as 20 tending to draw the pins into the vertical parts of the bayonet slots. The pins 19, 24 also extend outwardly and are adapted to co-operate with pins 13<a>, 14<a>, carried by collars 13, 14 secured to the hub 4. When the rod 1 is positioned so that the clutch 28 is in engagement, the upper collar 15 is drawn down and the pin 19 is pulled by the spring 20 into the end 17<a> of the bayonet slot to hold the clutch in action, causing the hub to travel upwardly from the lower end of the screw 3. As it reaches the upper end, the spring 27 is compressed until one of the pins 13a comes into the path of the pin 19 carried by the more rapidly rotating collar 15 and knock,; the pin out of the end of the bayonet slot, thereby releasing the stressed spring 27 which causes the rod to move axially to disconnect the clutch 28 and to throw the brake device 33 into action to hold the sleeve stationary for the return movement of the hub, the parts being again locked in engagement by the passage of the lower radial pin 24 into the lateral part of the lower bayonet slot 23. The number and positions of the releasing pins 13<a>, 14<a> may be varied. As applied to circular knitting machines, the drum 6, Fig. 2, is formed with a number of suitably spaced circumferential rows of holes to receive detachable and interchangeable pegs or cam pieces 36 adapted to act through a bell-crank 37 to operate a lever 38 with a suitably shaped nose 38<b> to press in certain of the sinkers traversing a cam track 40 in the sinker ring 41. The levers 37, 38 are designed to move quickly in striking and leaving the sinkers. The driving gears 10, 11 would be coaxial, with the axis of rotation of the needle cylinder and the arrangement such that one revolution of the machine occurs to one rotation of the pattern cylinder.