US2571913A - Stop motion for knitting machines - Google Patents

Description

1951 c. s. MARTIN ET AL 2,571,913

STOP MOTION FOR KNITTING MACHINES Filed Dec. 5, 1946 3 Sheets-Sheet l 0a. 16, 1951 h c. s. MARTIN ETAL 2,571,913

STOP MOTION FOR KNITTING MAQHINES Filed Dec. 5, 1946 3 Sheets-Sheet 2 Inventor:

By -0; ma 1 W 1951 c. s. MARTIN ET AL 2,571,913

STOP MOTION FOR'KNITTING MACHINES Filed Dec. 5, 1946 3 Sheets-Sheet 3 QZQ V I Q; Mair/126mm;

Patented Oct. 16, 1951 STOP MOTION FOR KNITTING MACHINES Charles Stanley Martin, Leicester, Lewis Henry Colton, West Bridgford, Nottingham, and Albert Edward Cooke, Leicester, England Application December 5, 1946, Serial No. 714,182 In Great Britain November 15, 1945 Claims. 1

This invention concerns the stop motion of knitting machines, the expression stop motion being employed herein to include a means whereby the knitting motions or certain thereof are suspended. The present invention is concerned solely with the Cottons patent or other straight bar knitting machines of the type having a needle bar and a presser, which bar and presser are relatively movable at each knitting cycle to cause the needles to press, and its object is the provision in a machine of this type of an improved stop motion. It may here be explained that the provision of a satisfactory stop motion in a straight bar knitting machine presents peculiar difiiculties in view of the cyclic knitting motions, the intermittent yarn feed, the great weight of the moving parts such as the needle bar, and the short interval available in each cycle for completing all operations of the stop motion, subsequent to the detection of a yarn breakage, if the knitting motions are to be modified or suspended in time to prevent a press-off.

As viewed from one aspect, the invention provides in a knitting machine of the type specified, a stop motion including means timed and operated directly or indirectly by the main cam shaft of the machine for preventing the needles from pressing. This prevention may be achieved by modifying or terminating the pressing motions of the needle bar (e. g. by displacing the latter to a non-pressing position) or by displacing the presser to an inoperative position, or by both expedients. The term presser is employed herein to include not only the usual continuous presser provided in the majority of straight bar machines, but also a presser which is sub-divided into a plurality of parts, and a presser which consists of a multiplicity of needle-pressing instruments.

The displacement may take place at a predetermined phase in the knitting cycle, preferably at or about the time when the operative yarn carrier is stationary at one end of its traverse. The mechanism for displacing the needle bar or presser preferably comprises two elements which pass each other at each knitting cycle and means for displacing one of them into or out of the path of the other so that in their relative movement the two elements are brought into contact and one of them is shifted thereby to efiect displacement of the needle bar or presser.

The foregoing and other features of the invention are incorporated in the constructions which will now be described with reference to the drawings as examples of the application of the invention to the displacement of the needle bar of a Cottons patent knitting machine, although, as envisaged above, similar means may be employed for displacing the one or more parts of the presser bar instead of displacing the needle bar.

In these drawings Fig. 1 is a cross section through the machine, showing the relevant parts;

Fig. 2 is an elevation, on a larger scale, showing an electromagnetic device for displacing one of the elements aforesaid, and also showing the mechanical means for disengaging the hand lever and press lever of the machine;

Fig. 3 is a plan View, partly in section, of the apparatus shown in Fig. 2;

Fig. 4 is a view of certain parts, looking on the left hand end on Fig. 2;

Fig. 5 shows the relative positions of certain of the parts, shown in Fig. 1, after the stop motion has operated;

Fig. 6 shows a modification;

Fig. 7 is a circuit diagram; and

Fig. 8 is a perspective view of a detecting mechanism.

The machine herein illustrated has driving means including a main cam shaft 3 by which cyclic knitting motions are imparted to the various moving parts.

In each section or division of the machine, the needle bar 1 is caused to make its pressing move-= ments through releasable mechanical connections operated by a press cam on the main cam shaft 3 of the machine, which cam rocks a press lever 4 which latter is connected by a hand lever 5 extending transversely of the machine to a lever or arm 6 depending from the needle bar I.

Thus, as the press lever 4 is rocked by the press cam, the needle bar I is moved towards and away from the presser I to cause the needles 8 to press. The hand lever 5 is releasably connected to the press lever 4, for which purpose it has a notch or recess 9 which is normally engaged with a stud vided with an operating abutment l2 which during the normal operation of the machine moves up and down past a displaceable stud I3 at one end of a rock lever 14 (carried by shaft i8) which stud I3 is displaceable when the stop motion detects a fault (such for example as the absence of the yarn or undue slackness in the yarn), into the path of saidabutment [2. Thus at a predetermined phase in the knitting cycle as the needle bar I travels downwards and towards the presser I to cause the needles 8 to press, this I descent brings the abutmentvonto ,thedisplaceable stud and thereby rocks the lever.. A pin IE on the front end of the lever .14 is located beneath a cam [6 on the-handleverE-and when this lever I4 is rocked, this pin [5 is raised into engagement with the cam 16 to raise the hand lever 5 and to disengage the recess-95h the "latter from the stud l 0 on the press lever 4. Thereupon, the weight of the needle bar I combined with the aforesaid spring ll, causes said bar to swing .away from .the :DIBSSBI 1.

7111 an .alternativeconstruction shown in Fig. =6,

a releasecam i9 is provided on the main cam shaft 3 which at each rotation of the "latter ;tr avels;p ast astud l3 on the'hand lever 5. This 1 stud !;3 is displaceable by the stop ;motion from its normal attitude in which it is out of .the path of the cam 19 into an attitude-in :which'itis located in :thepath of the cam. As a-resultfat a predetermined phase in the knitting cycle, the cam L9 raisesthe hand 'lever'5 to disengage the recessifl from the studlB-on-the press lever :4 with {the result that the needle bar swings forward away from the 'gpresser.

In each construction, the travel of the needle bar :I away from the presser is arrested by a second notch 20 in the hand lever 5 catching on the stud Ill. It will also be appreciated that in each of these constructions, although the stop -motion may detect .a fault during the travel of .the-yarn;-carrier,;itinitially serves to make "ready other mechanisms which result in the needle'bar being thrown out at ;a subsequent phase in the knitting cycle, the displacement of the needle bar being :timed by :the main cam shaft.

In each construction the displaceable stud [3 may 'be displaced :by electro-magnetic means I! under the control of a fault detector such for example .as that described in the specification of Patent No. 2,488,133, dated November 15, 1949.

It will be seen from Figs. '2, 3 and 4, that stud 43 is urged towards its protruding position by a spring 21, but is held in the retracted position because it extends through and wedges in a hole in a lever 22 pivoted at 2.3. This lever '22 carries :the armature :24 of an electro-magnet 25, so that when the latter is energized (upon operation of the detector) the armature is attracted and lever 22 is pulled against the action of a spring '26, to a position in which it ceases to bind on the stud i3 and the latter is shot forward by spring 2| to the extent allowed'by stop plate 21.

In Fig. 1 the detector apparatus is indicated generally by the reference numeral 28 and Fig. 7 shows a circuit diagram incorporating this apparatus. Numeral 2!! indicates a supply transformer and the detector apparatus 28 is inserted in the circuit between said transformer, the coil of magnet 25, and the usual stopand start switch 30 for the motor driving the machine. As it is desirable that the detector shall only operate at a predetermined phase in the knitting cycle, the circuit is controlled by contacts 31 operable by a cam 32 on the cam shaft 3.

In Figures 1, '7 and 8 the detector apparatus 28 is that described in the aforesaid patent. The

yarn T runs through a slub catcher 33 to eye 34 of a feeler 35 and thence to the yarn carrier 36 supplying the needles 8. This detector 35 is 6 pivoted at 3'! (Fig. 8) and normally rests against an adjustable stop 38 but when the carrier comes to either end of its traverse thefeeler is biased or swung sideways towards the contact 39 by a momentary impulse applied by means of an electro-magnet 40, Fig. 8, to the circuit to which is periodically completed by the contacts 3| Figure 7 and this magnet thereupon attracts its armaituredll -which,by means of a hook 42, pulls the feeleri35 sideways. If the thread T is present and :correct said thread resists this movement and terminates it short of the contact 39. On the-otherhand, if the thread is absent or is unduly slack, the movement will continue until contact 35a on the feeler strikes contact 39 to 0 complete the electric circuit to bring the stop imotion into pperation.

We-claim:

-l. In :a .knitting -machine=of the type having means for driving it, needles, a needle bar, and a 'presser, which bar and tpresser are relatively movable in each knitting cycle to cause the needlestmpress; a'stop motion including a detector for detecting the occurrence 10f a fault while the :machine is iknitting and -power-operated means, functioning :uponthe detection of-a fault and while the machine 'is .still :running :and deriving its power from said driVingmeans, for preventing the needles'from pressing by modify- :ingthe relation between theneedle bar and the -Dresser.

".2. In a knitting machine of the type having driving means for driving it, a needle "bar, a presser, which bar and'presser are movable relatively at each knitting cycle'to cause the needles to press, and releasable mechanical connections from the driving means for effecting said relative movements; :a stop motion comprising a'fault detec'ior and means, operable upon detection of a fault by the detector, for preventing the needles from pressing, which means comprises two elements which, prior to the needles pressing in each cycle, pass each other under power derived from the driving means, means for moving one of them into the path of the other upon detection of afault by the detector and for thereby producing displacement of one of them by power derived from the driving means, and mechanical connections extending directly from the displa-ccable element to the releasable connections and actuated by this power displacement for disengaging the releasable connections before the needles press.

3. In a straight bar knitting machine of the type having driving means for producing its, cyclic knitting motions, .a presser, a needle bar movable towards the presser to cause needles carried by the bar to press, and releasable connections be tween said driving means and the needle bar for impartin pressing movements to the latter; a stop motion comprising a fault detector, a displaceable driven element, direct connections between it and said releasableconnections whereby displacement of the driven element releases said releasable connections, an operating element driven cyclically by the driving means in a path which normally carries it past the driven element at a stage in each knitting cycle prior to that at which the needles press, and means operable upon detection of a fault by the detector, for

shifting one of the elements so that the operating element engages and displaces the driven element to release the releasable connections.

4. In a knitting machine of the type having driving means for producing its cyclic knitting motions, needles, and a presser and a needle bar movable relatively to each other in each knitting cycle to cause the needles to press and connections from said driving means for producing said relative pressing movements, a stop motion comprising a fault detector, and mechanism driven by said driving means for preventing the needles from pressing upon detection of a fault by the detector, which mechanism includes means for applying power and movement, derived from said driving means, to said connections to modify them.

5. In a straight bar knitting machine of the type comprising a presser, a needle bar for needles, a press lever for imparting pressing motions to the needle bar, a hand lever for transmitting pressing motions from the press lever to the need1e bar and having a releasable connection with the press lever, the needle bar being movable to a non-pressing position upon release of the hand lever from the press lever, and a main cam shaft for imparting cyclic knitting motions to the machine, including pressing movements of the press lever; a, stop motion for disengaging the hand lever from the press lever upon detection of a fault and thereby preventing the needles from pressing upon detection of a fault, including a fault detec'tor, a lever movable under power derived from the cam shaft to release the hand lever from the press lever, a driven element carried by the release lever, an operating element movable cyclically with the needle bar and normally passing the driven element at a time in each cycle before the needles press, and means operable upon detection of a fault for shifting one of these elements to a position in which the operating element engages the driven element and rocks the release lever.

CHARLES STANLEY MARTIN.

LEWIS HENRY OOLTON.

ALBERT EDWARD COOKE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,040,047 Haines, Jr., et a1. May 5, 1936 2,265,100 Colton Dec. 2, 1941

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