Textiles: knitting – Feeding – Strand tensions
Patent
1986-12-10
1988-08-16
Feldbaum, Ronald
Textiles: knitting
Feeding
Strand tensions
D04B 1544
Patent
active
047634910
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
This invention relates to domestic knitting machines in which the usual needle bed carries a plurality of conventional latch needles and a carriage slidable lengthwise of the needle bed having on its underside a cam groove for successively engaging the butts of all the operative needles to be used for a given knitting operation and reciprocating them in accordance with the chosen pattern of the fabric to be produced. Such domestic knitting machines can be used in two modes:
(1) normal knitting, in which one or more yarns is fed to the carriage from a ball or cone of yarn at the rear of the machine via an overhead spring-loaded tensioning arm resiliently mounted on the top of a mast or pillar carried on the back of the needle bed;
(2) "Intarsia" or picture knitting in which a plurality of yarns, generally of equal thickness, and usually of diffferent colors, are drawn from their respective balls or cones at the front of the machine (usually placed on the floor) and laid in the open hooks of the appropriate needles which are then reciprocated by a special "intarsia" carriage. Before each traverse of the carriage adjacent yarns are crossed over, first one way then the other alternately, in order to avoid gaps or holes in the fabric at the boundaries of different colors.
In both modes, it is desirable to maintain a constant, relatively light, tension in the yarn as it is fed to the needle. In the first or normal mode of knitting, it is sometimes desired to knit a yarn which is a composite of a plurality of separate threads or filaments which differ as to color or nature e.g. a mixture of natural and artificial threads or filaments - which are coalesced into a single composite yarn as they are fed to the carriage. Prior to their coalescence, however, tensions in the several filaments are random, and differences can result in the "looping" of a slicker filament which in turn can lead to its being missed by a needle.
BACKGROUND ART
Hitherto, when knitting with a composite yarn composed of a plurality of different filaments with the machine set up for operation in mode (1) above, the only way of ensuring equality of length and tension among all the filaments when they reach the needles has been to twist them together first before feeding them as twisted yarn via the overhead springloaded tensioning arm at the head of the mast. But the only way of achieving such twisting is by bodily spinning all the supplies of the filaments - whether in the form of balls or cones or other kinds of package - as opposed to spinning the filaments after they have been drawn from stationary packages. When the number and variety of packages is large the mechanical problem of handling the whole assembly to be spun calls for precision engineering to combat problems of unbalanced rotating masses, and hence the cost, size and weight are serious limitations on the viability of the system for domestic knitting machines.
In the absence of such elaborate means for equalizing the lengths of and tensions in the component filaments of a composite yarn, the machine operator must constantly finger the separate filaments as they are fed down to the carriage in order to smooth out any individual slackness in the filaments, and the human factor involved can result in its own problems of inequality of tension.
In the case of intarsia knitting, it is common practice for the knitter to gather all the yarns together as they are drawn from their respective cones or balls and to hold them in the fingers of one hand while they are first laid by the other hand on the appropriate needles and crossed over in the usual way in order to preserve the integrity of the finished fabric at each boundary between different yarns, and then knitted by the carriage. By this system accurate control of the tension in each yarn is subject to human error, and irregularities are inevitable, even for experienced knitters. Moreover, this manual system of feed of the yarns to the needle does not eliminate the risk of tangling of the yarns, involving frequ
REFERENCES:
patent: 2912185 (1959-11-01), Vossen
patent: 3146969 (1964-09-01), Lindsey
patent: 4398681 (1983-08-01), Kupper
patent: 4526019 (1985-07-01), Betts et al.
patent: 4535609 (1985-08-01), Goller et al.
Wilson Joan A. M.
Wilson Trevor E.
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