Needle bar for a tufting machine

Abstract

A needle bar for a tufting machine, comprising a main bar having a row of holes uniformly spaced at a coarse pitch, a multiplicity of contiguous segments fitted into a longitudinal location groove in one face of the main bar, each segment having a peg accommodated in one of said holes in the main bar and retained therein by a locking screw and a row of finer holes, disposed parallel to the holes in the main bar and uniformly spaced at a finer pitch than the holes in the main bar, and needles mounted in groups in the holes in the segments to extend away from the main bar and retained in said holes by locking screws, the number of needles in each group being equal.The conventional needle bar for a tufting machine consists of a massive bar, of rectangular cross section, conveniently 1" square, which is reciprocated vertically by push rods and is formed, at uniform pitch, with vertical throughgoing holes into which the shanks of the needles are fitted and secured in position by screws fitted into horizontally extending throughgoing holes in the bar.Difficulty arises, however, in the manufacture of the needle bar when the gauge of the machine, i.e. the spacing between adjacent needles, is required to be very fine, e.g. 1/16" or 1/10". Thus in a typical case, a needle bar 1721/2" long may require to be drilled with no less than 1662 holes, each having a diameter of 0.08", disposed at a pitch of 0.10". Since the required drill is extremely fine, it is extremely difficult to drill these holes accurately and in the event of error the entire needle bar must be scrapped.It is possible to mitigate this difficulty by the use of a staggered needle bar, having two rows of needles with the needles in one row pitched midway between those in the other row. This expedient is not, however, available in the case of fine gauge machines for making cut pile fabric because there is insufficient clearance between the needles in the two rows for the passage of the loopers, which catch the loops of yarn projected through the backing fabric by the needles.The invention provides a needle bar for a tufting machine, comprising a main bar having a row of holes uniformly spaced at a coarse pitch, a multiplicity of contiguous segments fitted into a longitudinal location groove in one face of the main bar, each segment having a peg accommodated in one of said holes in the main bar and retained therein by a locking screw and a row of finer holes, disposed parallel to the holes in the main bar and uniformly spaced at a finer pitch than the holes in the main bar, and needles mounted in groups in the holes in the segments to extend away from the main bar and retained in said holes by locking screws, the number of needles in each group being equal.

Description

Claims

1. A needle bar for a tufting machine, comprising a main bar having a row of holes uniformly spaced at a coarse pitch, a multiplicity of contiguous segments fitted into a longitudinal location groove in one face of the main bar, each segment having a peg accommodated in one of said holes in the main bar and retained therein by a locking screw and a row of finer holes, disposed parallel to the holes in the main bar and uniformly spaced at a finer pitch than the holes in the main bar, and needles mounted in groups in the holes in the segments to extend away from the main bar and retained in said holes by locking screws, the number of needles in each group being equal.

2. A needle bar according to claim 1, wherein the locking screws retaining the needles in each segment are disposed in two rows in staggered relationship.

3. A needle bar according to claim 2, wherein the locking screws retaining the outermost needles in each segment are disposed off-centre with respect to the needles.