Abstract: A high frequency welding device for welding plastic sheets, in which the high frequency energy is provided by fixed-frequency oscillator, preferably by using a quartz crystal amplifier, whose frequency does not change during the welding process. The output circuit is designed to have a resonance curve which, before the occurence of any change in the output and coupling circuit characteristics due to the welding process, intersects with the fixed frequency of the oscillator at a "operating point" which is on the slope of the resonance curve descending to lower frequencies. The circuit components are selected to behave in such a manner that the resonance curve undergoes a shift toward lower frequencies, with the fixed-frequency "operating point" rising across the peak of the resonance curve to a point on the slope of the curve descending to lower frequencies, as the welding process progresses.

Abstract: As the carriage of a flatbed knitting machine traverses the needle bed, a lse generator which comprises a toothed disc and two cycle signallers at its circumference produces pulses in synchronism with the carriage movement and corresponding to the needle cycle for electronic control of the machine. The toothed disc has a tooth pitch which corresponds in whole number multiples with the pitch of the needles in the bed. The pulse generator may be located on the machine frame or on the carriage. In the former case the carriage can have a pick-up which entrains a chain stretched on the machine frame with the toothed disc rotatable jointly with one of the sprocket wheels for the chain. In the latter case the toothed disc, carried by the carriage may be rotated by a coupled pinion which meshes with a rack stationary on the frame and co-extensive with the traverse of the carriage. In each case the pulse generator produces synchronized control pulses without direct scanning of the needles in the bed.

Abstract: A flatbed knitting machine having electronic control includes memory and trol units associated with the machine, a data entry device (11) for the entering of data into the machine, and also indicator means (12, 13), wherein upon the entering of data by way of the data entry device the indicator means provides a guidance report for the user, data called up for entry can be directed to one of several types of machine, each next step in the entry of data can only be effected in accordance with the requirement shown by the indicator means, and at least one key (.noteq.) is provided for stepping-on the indicator means. For extremely simple operation of the data entry device (11) and in order to achieve complete programming of the patterning and of the usual control data for the plan run of the machine, with all the parts necessary for the functioning of the entry device built into the entry device itself, the data entry device (11) has only one keyboard with ten number keys (0 to 9), a decimal point key (.

Abstract: In a flatbed knitting machine having one or more carriages movable reciprocally or, on a closed path with respect to one or two needle beds, control data is conveyed to the or each carriage by light or other electromagnetic radiation or acoustically, one or more data transmitters being located externally of the needle bed or beds and the carriage having means for processing and storing data relating to at least one knitting course. The transmission zone is screened or otherwise shielded against interference. The transmitted signals may be modulated in various ways and alarm and timing control arrangements are described.

Abstract: A hood movable in the direction in which pinching of the operator's hand would occur extends across the stationary part and between the stationary part and the movable part of a straight knitting machine such that a machine stopping mechanism can be triggered by movement of the hood by impact of the hood by the operator's hand to insure stopping of the machine prior to the machine movable part reaching the stationary part covered by the hood.

Abstract: A hood which is mounted to and shields a slide which in turn is longitudinally movable on a straight knitting machine, has contact devices for triggering a stopping mechanism for the knitting machine slide on the end faces of the hood as viewed in the direction in which the slide travels, with the hood being displaceable longitudinally relative to the slide through a distance corresponding to at least the braking distance of the slide after the stopping mechanism is triggered.

Abstract: A straight knitting machine comprises needles in a needle bed and cam means for actuating the needles for casting on, loop forming and stitch transfer, during which operations the needles are selected by lowering or lifting the needles into or out of the needle bed so that a foot of each needle completely or partially projects from the needle bed, or is withdrawn completely into the needle bed and is thus selectively engaged by lifting portions of the cam means. The needles are raised by spring means and are pressed into the needle bed by pressure strips mounted on a slide. A selector element is associated with each slot in the needle bed for transmitting control movements from the pressure strips to the needles and a shaft of each needle is retained in an intermediate member. The intermediate members are provided with fixed feet arranged in rows for engagement by the pressure strips and with a further foot movable selectively into different rows for engagement by the pressure strips.

Abstract: A shift device for the needle bed of a straight knitting machine comprises an indexing disc having a periphery movable substantially at right angles to the intended direction of shift of the needle bed and stoppable in selected positions. A plurality of eccentric indexing boss means adjustably mounted on the disc periphery for eccentric displacement about spindles extending radially of the disc, and a guide channel is securable to the needle bed oriented in the direction of the disc periphery. The width of the guide channel substantially corresponds to the diameter of each eccentric boss means and the eccentric boss means engage in the guide channel for establishing a predetermined shift of the guide channel substantially at right angles to the peripheral movement of the disc in accordance with the eccentricity of the boss means.

Abstract: A flat knitting machine comprises a needle bed and a carriage traversible along the needle bed. Stitch cams presettable in a plurality of different positions according to a desired knitting pattern are provided, and an adjustably positioned ramp in the needle bed fixed to a slide is adapted to displace a cooperating stitch cam into a selected position. Means are provided on the carriage for clamping the stitch cam in the position to which it has been displaced by the ramp and a slide to which the ramp is attached is raisable by control cam means preceding knitting cams in the carriage.

Abstract: A straight knitting machine includes a plurality of sliding heads 1 driven around a guide track 2 by chain and sprocket means 3, 5. A plurality of holders 8 for yarn spools 9 are positioned above their associated sliding heads and are driven around guide tracks 10, 11 by chain and sprocket means 12, 14 coupled to the same drive shaft 15 as the chain and sprocket means 3, 5. Electrical connections for safety switches and thread delivery motors are made by sliding contacts on the heads 1 which engage stationary contacts on the straight portions of the guide path.

Abstract: A limit switch arrangement for controlling the patterning and working width of knitted articles on a straight knitting machine includes a plurality of magnetically responsive switch on the movable carriage of the machine and a plurality of permanent magnets are mounted in an axially affect manner on a holder which is axially adjustable in the direction of travel of the carriage.