US2271902A - Knitting machine - Google Patents

Description

1942- A. E. STEWART 2,271,902

KNITTING MACHINE Filed Nov. 6, 1959 2 Sheets-Sheet 1 ATTORNEY.

Feb. 3, 1942. A. E. STEWART 2,271,902

KNITTING MACHINE Filed Nov. 6, 1959 2 Sheets-Sheet 2 INVENTOR. [B I ATTORNEY;

Patented Feb. 3, 1942 KNITTING MACHINE.

Albert E. Stewart, Franklin, N. H., assignor to Acme Knitting Machine & Needle Company,

Franklin, N. H., Hampshire corporation of New Application November 6, 1939, Serial No. 303,089

9 Claims. (01. 66-158) This invention relates to knitting machines and is more especially concerned with mechanisms designed to stop a machine of this type automatically in the event that the thread with which the knitting operation is being performed breaks or runs out.

Such mechanisms are in common use, and they are very valuable in preventing the production of imperfect work under circumstances such as those just described. Also in certain types of machines they prevent the breakage of needles or latches which would occur if one of two threads running to the needles breaks and the nature of the knitting instrumentalities is such that the machine continues to operate with the remaining thread which accumulates or piles up- On the needles.

The invention aims to improve stop mechanisms of this general character with a view to simplifying their construction, making them more reliable, and reducing the expense of manufacturing and installing them.

The nature of the invention will be readily understood from the following description when read in connection with the accompanying drawings, and the novel features will be particularly pointed out in the appended claims.

In the drawings,

Figure 1 is a side elevation of parts of a circular knitting machine equipped with an automatic stop mechanism constructed in accordance with this invention;

Fig. 2 is a front view of the machine and stop mechanism shown in Fig. 1; and

Fig. 3 is an elevation, on a somewhat larger scale, of those parts at the upper end of the mechanism.

The machine shown in the drawings is designed more especially for the automatic production of circular knit stockings, The illustration of it, in general, has been limited to those features with which the present invention is more especially concerned. It includes a needle cylinder 2 mounted on a base 3 of a common form, and a thread ring 4 cooperating therewith. A single thread T is shown running from a suitable supply, bobbin, or spool (not shown) through a thread tension device 5 of a common form, and thence to the knitting instrumentalities.

It is a common practice in machines of this type to include a clutch or a fast and loose pulley in the driving connections so that the machine may be stopped by throwing the clutch out or shifting a driving belt from the fast-to the loose pulley. In either case a knock-off mechanism is usually provided to control the clutch or the belt. A common arrangement is that shown in Fig. 2 in which a rock shaft 6 is provided to operate the clutch or the belt shipper, and the 7 rock shaft, in turn, is operated by a hand lever l. A link 8 is slidably connected to the lever and is provided at its end remote therefrom with a notch [0. Thus the link forms a latch, and a coiled spring l2 connected with it, as shown in So far as the general organization above described is concerned, it is of a common form and it may be of any other suitable or convenient nature.

This invention is directed to the provision of a controlling means for the knock-off mechanism which will release the latch when the thread breaks or fails for any reason, as by running out. In prior constructions the operation of such controlling means is dependent upon the use of springs, and it is one of the objects of this invention to eliminate springs, with their inherent defects and objectionable characteristics, from the action of those parts which feel for the presence of the thread and preferably from the entire controlling mechanism.

The controlling mechanismillustrated in the drawings comprises a thread guiding finger or feeler l5 which may conveniently consist of a wire bent into suitable form and having an eye or hook at its forward end to engage and guide the thread T. This feeler is adjustably clamped in a holder It by means of a set screw H, the holder being mounted to rock or pivot freely on a rock shaft [8. The rearward end portion of the wire I5 is bent, as shown in Fig.v 1, to provide a portion above, and parallel with, the main body breaks or runs out, the feeler is instantlyxre-i leased, the weight 20 swings in a counter-clockwise direction around the axis of the rock shaft l8, together with the support [6, and after swinging for a considerable distance and thus acquiring momentum, the feeler wire strikes a pin 22 fixed in an arm 23 which is pinned to the rock shaft H3. The outer end of this rock shaft has a plate 24 secured thereto, and a pin 25 projecting laterally from said plate normally overlies the end of a weighted lever 26, as shown in Fig. 1, and thus restrains it, or acts as a latch for it. At this time the pin is in the same vertical plane with the axis of the rock shaft l8 to which the pin supporting plate 24 is secured. The shaft !8 rocks freely in its bearings 2'!--21 and consequently, when the feeler I strikes the pin 22, as above described, it rocks the shaft It in a counterclockwise direction, Fig. 1, and thus moves the pin or latch 25 off the end of the lever 26. This action is accomplished with certainty because of the relatively heavy impact delivered by the feeler, and the parts movable with it, when it strikes the pin 22.

Immediately upon the release of the weighted lever 26, it swings about its fulcrum 28 and the pin or screw 33 projecting laterally from it and running in the slot 3| of the link 32, strikes the lower end of this slot with a very substantial degree of momentum. This blow or impact is transmitted to the upwardly extending arm A of the bell crank lever l3 and trips the latch 8 of the knock-off mechanism, allowing it to shut down the machine.

It will be seen from the foregoing that the controlling mechanism here shown includes a primary latch H)l3 which normally restreins the knock-off mechanism but is arranged to be released by the action of the gravity impact element 2%. This element, in turn, is normally restrained by a secondary latch 25 adapted to be released upon the breaking or running out of the thread by the action of a second gravity impact element consisting of the weighted feeler assembly. Such a mechanism is extremely reliable in operation. At the same time it is simple in its construction, the parts can be manufactured and assembled economically, and it is of such a nature that the matter of installation is relatively simple. Also, because of the mounting of the weight 20 above the axis of the pivot IS on which the feeler swings and the adjustability of this weight, the force exerted by it to tension the thread can be adjusted very precisely, while at the same time the impact which it will deliver when the thread breaks is ample to operate the latch 25.

In the event that the work being produced requires the substitution of one or more threads for that shown at T, as for example, in knitting the heel and toe of a stocking, the thread T will be cut off by the usual thread changing mechanism and its end may be left free, or comparatively so. Thus, if such a thread change were to occur, the feeler would immediately be released and would initiate the operation of the knock-off mechanism, thus shutting down the machine. In order to prevent such an occurrence, the mechanism above described preferably is placed under the control of the pattern mechanism of the machine. As shown in Fig, 1, this object is accomplished by mounting a cam disk 34 on the cam shaft 35 of the pattern mechanism and providing this disk with one or more cam lugs such as B or C where they will operate a lever 36. A link 31 connects this lever with another lever 38, fulcrumed on the machine frame at 40, Figs. 2 and 3. So long as the lever 36 is not resting on a cam lug on the disk 34, its weight operates through the connections just described to hold the right-hand end, Figs. 2 and 3, of the lever 38 against the lower face of the feeler holder l-6 where it maintains this feeler, the rock shaft 18 and the latch pin 25 locked against movement under the influence of those forces which otherwise would actuate them. When so looked a lug 39, Fig, 3, projecting downwardly from the holder It bears against the rearward side of the right-hand end of the lever 38 and prevents any rotation of the holder out of its operating position. At this time the thread T is not being used but the knitting instrumentalities are working with another thread or threads. When, however, the pattern mechanism changes threads again and brings the thread T into feeding position, it also moves a lug under the end of the lever 36 and releases the brake lever 38. In a typical stocking the lugs B and C would control the lever during the knitting of foot and leg portions, respectively, of the stocking, and the feeler mechanism would be held in an inactive or inoperative condition during the knitting of the remaining portions of the stocking.

After the knock-off mechanism has been actuated and has shut down the machine, and the starting lever 1 is again swung to the left, Fig. 2, to start up the machine, the link -8 is automatically latched by the trip lever 3 due to the fact that it tends to swing in a counter-clockwise direction, Fig. 1, by gravity. The feeler mechanism is returned to its normal position, as shown in Fig. l, and the lever 26 is re-latched by the pin 25, also as there shown. This completes the re-setting of the controlling mechanism. A second pin 4|, Fig. 1, carried by the plate 24, engages a frame plate 42 when the latch pin 25 is in its operative position and holds the rock shaft and the arm 23, pinned thereto, in position for subsequent operation by the feeler.

While I have herein shown and described a preferred embodiment of my invention, it will be evident that the invention may be embodied in other forms without departing from the spirit or scope thereof,

Having thus described my invention, what I desire to claim as new is:

1. In an automatic stop mechanism for knitting machines, the combination with a knock-off mechanism, of controlling means therefor comprising primary and secondary latches, a gravity impact element normally restrained by the thread running to the knitting instrumentalities and adapted when released by the breaking of the thread to release the secondary latch, a second gravity impact element normally restrained by said secondary latch but arranged to be released by said first impact element for releasing the primary latch and means continuously connecting said second gravity impact element with said primary latch and serving to transmit motion from one of these parts to the other.

2. In an automatic stop mechanism for knitting machines, the combination with a knock-off mechanism, of controlling means therefor including a latch restraining said mechanism, a weighted member connected with said latch to release it, means supporting said member for operative swinging movement, a second latch normally restraining said member, and a pivoted and weighted feeler normally controlled by the thread running to the knitting instrumentalities and operable upon the breakage of said thread to release said second latch through the momentum developed in its movement out of its operative position and means connecting said weighted member with the first mentioned latch for tran mitting movement from each of said members to the other.

3. In an automatic stop mechanism for knitting machines, the combination with a knock-01f mechanism, of controlling means therefor including a latch restraining said mechanism, a weighted member connected with said latch to release it, a second latch normally restraining said member, a feeler having a horizontally extending arm engaging the thread running to said knitting instrumentalities, a horizontal pivot supporting said feeler, a weight movable with said feeler and mounted directly above the pivotal support for the latter in an approximately balanced position but so biased as to apply tension to said thread, whereby when the thread breaks or runs out the feeler will be released and said weight will swing downwardly around said pivot, and means arranged to be struck by a part movable with said weight during such swinging movement to release said second latch due to the impact of said part.

4. In an automatic stop mechanism for knitting machines, the combination with a knock-off mechanism, of controlling means therefor including a latch, and means for releasing said latch comprising a feeler supported in a generally horizontal position and engaging the threadrunning to the knitting instrumentalities, a weight connected with said feeler to be moved thereby in response to variations in tension of said thread, means supporting said weight for swinging movement about an axis directly under it, said weight being so positioned with reference to said axis that it is approximately balanced but is so biased as to operate through its connections with said feeler to apply a moderate degree of tension to the thread, whereby when the thread breaks or runs out the feeler will be released and said weight will swing downwardly around said pivot into a latch releasing position, said weight and the feeler assembly having sufficient mass to deliver an impact serving to release the latch.

5. In an automatic stop mechanism for knitting machines, the combination of a thread guiding feeler, means supporting said feeler in a generally horizontal position, said means including a holder mounted to swing about a horizontal axis disposed transversely to the feeler, a weight mounted for movement around said axis and connected with said feeler to be moved thereby in response to variations in the tension of said thread, said weight being mounted directly over said axis in an approximately balanced position, and mechanism for stopping said machine including an operating element 25 and a latch normally restraining said element but mounted for releasing movement around said axis and arranged to be released by the impact of the feeler assembly, including said weight, delivered upon the breaking or running out of the thread.

6. In an automatic stop mechanism for knitting machines, the combination with a knock-oil mechanism, of controlling means therefor including a latch, a pivoted and weighted feeler normally restrained by the thread running to the knitting instrumentalities, connections arranged to be operated by the release of said feeler for tripping said latch, and means controlled by the pattern mechanism of the machine for locking said feeler in its operative position during certain of the knitting operations and automatically releasing it to the control of said thread at other times.

7. In an automatic stop mechanism for kniting machines, the combination with a knock-oil mechanism, of controlling means therefor including a latch, means for releasing said latch comprising a feeler engaging the thread running to the knitting instrumentalities, a pivoted and weighted support for said feeler normally governed as to position by the action of said thread on said feeler, said feeler'assembly being so biased as to swing by gravity into a latch releasing position upon the breakage of said thread and having sufficient mass to deliver an impact serving to release the latch, and means controlled by the pattern mechanism of the machine for locking said controlling means in its operative position but in an inoperative condition during the knitting of certain portions of the work and releasing it automatically while other portions are being knit.

8. In an automatic stop mechanism for knitting machines, the combination with a knock-off mechanism, of controlling means therefor comprising primary and secondary latches, a gravity impact element normally restrained by the thread running to the knitting instrumentalities and adapted when released by the breaking of the thread to release the secondary latch, a second gravity impact element normally restrained by but arranged to be released by said first impact element for releasing the primary latch, and means controlled by the pattern mechanism of the machine for holding said secondary latch releasing means in its operative position but in an inoperative condition during the knitting of certain portions of the work and restoring it again to an operative condition while other portions are being knit.

9. In an automatic stop mechanism for knitting machines, the combination of a thread guiding feeler, means supporting said feeler in a generally horizontal position, said means including a holder mounted to swing about a horizontal axis disposed transversely to the feeler, a weight mounted for movement around said axis and connected with said feeler to be moved thereby in response to variations in the tension of said thread, said weight being mounted directly over ing a slotted link.

ALBERT E. STEWART.

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