US2817222A - Knitting machine needle - Google Patents

Description

H. C. NOE

KNITTING MACHINE NEEDLE Filed March 1'7, 1954 Dec;24, 1957 2,817,222

INVENTOR & glam/a!0.11/28 KNITTING MACIflNE NEEDLE Harold C. Noe, Upper Montclair, N. J., assignor to Kidde Manufacturing Co., Inc., Bloomfield, N. J., a corporation of Delaware Application March 17, 1954, Serial No. 416,790

6 Claims. (Cl. 66-121) The present invention relates to needles for knitting machines, and, more particularly, to such needles of the latch type.

Latch needles generally comprise a shank having a longitudinal slot formed in the front face thereof, a hook at the upper end of the shank having a bend of about 180, and a latch pivotally mounted in the slot and having a spoon at its free end adapted to engage the point of the hook when the latch is in its closed or upper position. When the latch is in its open or lower position, the back of the spoon is adapted to engage the cheeks of the shank which define the latch receiving slot.

Heretofore, such needles were considered satisfactory for use in connection with knitting machines, for example of the Raschel type, which were operated at speeds of about 100 to 200 courses per minute. However, in the past five years, Raschel knitting machines have been improved in such a manner that they can now be operated at speeds of about 500 to 600 courses per minute. As a consequence of these high operating speeds, excessive breakage of the heretofore satisfactory conventional latch needles has been experienced. The time consumed in replacing broken needles thereby somewhat offsets the time gained by faster operation, with the net result that the fabric output of the machines is not materially increased.

Such needle breakage is attributed to the fact that, when the machines are operated at high speeds, the force acting on the latch to swing it up and down greatly increases the kinetic energy of the latch, such energy being a function of the square of the needle velocity. It therefore follows that needle breakage is induced when the fast moving latch strikes stationary portions of the needle and the latch is momentarily brought to rest.

It has been discovered that needle breakage occurs at the hook and at the cheek portions below the pivot. The former breakage is primarily due to the fact that the latch strikes the point of the hook to exert a bending moment thereon which creates a strain concentration at about the midpoint of the bend of the hook when such forces are applied at high frequencies. The latter breakage is primarily due to the fact that the rounded or somewhat V-shaped back of the spoon seeks to enter the slot when the latch is swung down either by inertia or the pull of the yarn. This imparts a combined wedging and hammering action of the spoon on the edges of the cheeks, whereby the cheeks are chipped or slivered and eventually crack to cause what is known as check breakage. Also, this results in the roughening of the latch and cheeks to an extent whereby the thread being knitted is subjected to being frayed or severed upon engaging the impaired cheeks.

Accordingly, the present invention aims to overcome needle breakage and impairment due to the foregoing or other causes.

An object of the present invention is to provide a latch needle suitable for use in connection with knitting ma- 7 chines operated at high speeds which is simple, practical and economical in construction.

nited States Patent f Patented Dec. 24, 1957 "ice Another object is to provide such a needle which will resist hook or point breakage.

A further object is to provide such a needle which will resist cheek breakage or impairment thereof.

Other and further objects of the invention will be obvious upon an understanding of the illustrative embodiment about to be described, or will be indicated in the appended claims, and various advantages not referred to herein will occur to one skilled in the art upon employment of the invention in practice.

In accordance with the present invention, the foregoing objects are accomplished by providing a needle having a hook which resists breakage thereof and having a spoon which cooperates with the checks to prevent breakage or impairment thereof.

A preferred embodiment of the invention has been chosen for purposes of illustration and description, and is shown in the accompanying drawing, forming a part of the specification, wherein:

Fig. 1 is a side view of the upper portion of a latch in its upper or closed position.

Fig. 2 is a similar View with the latch in its lower or open position.

Fig. 3 is a front view of the needle as shown in Fig. 1.

Fig. 4 is a sectional view taken along the line 4-4 on Fig. 1.

Fig. 5 is a sectional view taken along the line 5-5 on Fig. 2.

Fig. 6 is a fragmentary side view of the hook.

In Figs. 1 to 3, the needle is shown on an enlarged scale of about 25 to 1; whereas, in Figs. 4 to 6, the scale is about 50 to 1.

Referring to the drawing in detail, there is shown a needle generally comprising a shank 10 and a latch 11. The shank has a hook 12 at its upper end and is formed with a longitudinal slot or groove 14 at the front face thereof defined by cheeks 15 (Fig. 3). The latch is pivotally mounted in the groove by a pin or rivet 15 and has a spoon 18 at its free end adapted to contact the point of the hook.

As shown in Figs. 4 and 5, the face of the spoon is recessed or dished out in the conventional manner. However, the back of the spoon, instead of being rounded or V-shaped, is formed in a manner to prevent wedging itself between the cheeks. This is accomplished by forming the back of the spoon with a generally rectangular lengthwise extending rib 20 having a width slightly less than that of the slot 14 and about equal to that of the body or blade of the latch. At the shallow or lower portion of the spoon (as viewed in Fig. 1), the back of the spoon has a pair of shoulders 21 which meet the rib 20 at about right angles (Fig. 5).

When the latch is moved into its lower position (Figs. 2 and 5), the rib 20 freely enters the slot 14 and the shoulders 21 contact the cheeks 15 adjacent the inner edges thereof. The shoulders, by meeting the front surfaces 22 of the cheeks almost squarely, do not impart any wedging action thereon. Frequent contact between the shoulders 21 and the surfaces 22 will not impair the cheeks, but may result in truly flattening of shoulders 21 and the surfaces 22 which initially are slightly rounded due to the method employed in making the needle shank and latch. Such flattening is beneficial and takes place without roughening or otherwise impairing the cheeks or the spoon.

As shown in Fig. 6, the hook 12 differs from the con-- ventional design in that the tip thereof comprises a pair of converging faces 24 meeting at an edge 25 substantially parallel to the shank. The upper edge of the hook extends through an arc of about and the lower edge- 0 of the hook extends through an arc of about whereby 3 of this configuration, the force exerted by the latch on the hook is applied in a substantially horizontal direction, that is, at a point disposed in a plane perpendicular to the longitudinal axis of the shank; and the midpoint of the bend of the hook is so close to the vertical section of the shank that any bending moments are readily resisted by this section because of its greater width and thickness than that of the conventional midpoint of the bend of the hook which is spaced at an arc of 90 from the shank. Consequently, the forces of the latch are absorbed without inducing hook breakage.

Another advantage derived from the short bend is that the yarn guides need barely enter between adjacent needles. This is very desirable in fine gauge knitting since it effects shortening of the stroke of the needle for a latch of a given length and facilitates higher knitting speeds.

The hook and latch are so constructed and arranged that the tip of the latch spoon is about in horizontal alignment with or extends just slightly outwardly and above the top of the bend of the hook (Fig. 1), whereby the latch covers the wear point of the needle and stitches are cast off from the latch rather than the hook. This also reduces yarn breakage when knitting at high speeds.

A still further feature of the short hook is that the latch makes contact therewith when substantially parallel to the longitudinal axis of the shank of the needle.

The hook also is less likely to break due to yarn tension applied at the lower edge adjacent the point because of the short distance to the midpoint of the bend and the resulting small bending moment exerted on the hook by the yarn. Such forces are further resisted by the heavier than normal hook cross-section near the point because the bend of the hook is not tapered as it approaches the point.

Also, the bend of the hook has flattened side faces 26 which extend almost to the tip of the hook.

From the foregoing description, it will be seen that the present invention provides a stronger and more durable latch needle than utilized heretofore Without increasing the weight or dimensions of the needles but actually reducing the same. Such needles will resist breakage when used for long periods in connection with machines operated at the high speeds previously indicated herein.

As various changes may be made in the form, construction and arrangement of the parts herein, without departing from the spirit and scope of the invention and without sacrificing any of its advantages, it is to be understood that all matter herein is to be interpreted as illustrative and not in any limiting sense.

I claim:

1. A latch needle comprising a shank having a straight upper portion, a hook at the upper portion of said shank having a bend of about and terminating in a tip, a latch for contacting said tip, and means for pivotally mounting said latch on said shank, said tip facing a plane passing through said latch mounting means and the lower portion of said shank.

2. A latch needle according to claim 1 wherein said latch makes contact with said tip when substantially parallel to the upper portion of said shank.

3. A latch needle according to claim 1, wherein the free end of said latch extends slightly beyond the outermost portion of the bend of said hook when said latch contacts said tip.

4. A latch needle according to claim 1, wherein the sides of said hook are flattened from said tip to said shank.

5. A latch needle according to claim 1, wherein said tip consists of a pair of converging faces providing an edge contacted by said latch lengthwise with respect to said latch.

6. A latch needle according to claim 1, wherein said shank has a longitudinal slot at the front face thereof below said hook defined by a pair of cheeks, and said latch is pivotally mounted in said slot by said latching mounting means and has a spoon at its free end provided with a surface on one side for contacting said hook and provided with a configuration on the opposite side thereof, said configuration including a longitudinally extending rib having parallel sides adapted to freely enter said slot and including shoulders extending lengthwise at the respective sides of said rib and being dispossed at about right angles thereto thereby providing zones adapted to substantially fiatly contact only the front surfaces of said cheeks to prevent said spoon from being wedged into said slot and causing cheek breakage.

References Cited in the file of this patent UNITED STATES PATENTS 1,168,039 Swinglehurst Jan. 11, 1916 1,354,096 Fels Sept. 28, 1920 1,468,518 Scott Sept. 18, 1923 1,752,155 Egly Mar. 25, 1930 1,848,900 Messing Mar. 8, 1932 2,249,780 Page July 22, 1941

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