US3206948A

US3206948A - Thread shearing device

Info

Publication number: US3206948A
Application number: US359355A
Authority: US
Inventors: Bella Italo Della; Scholz Bernhard
Original assignee: Individual
Current assignee: Individual
Priority date: 1963-04-12
Filing date: 1964-04-13
Publication date: 1965-09-21
Anticipated expiration: 1982-09-21
Also published as: GB1053622A

Description

p 21, 1965 I. DELLA BELLA ETAL 3,206,948

THREAD SHEARING DEVICE 2 Sheets-Sheet 1 Filed April 13, 1964 Inventors: ITALO DELLA BELLA BERNHAPD SCHOLZ P 1955 l. DELLA BELLA ETAL 3,206,948

THREAD SHEARING DEVICE 2 Sheets-Sheet 2 Filed April 15, 1964 In ventom I TA LO DELLA BELLA BERNHARD SCHOLZ AGENT United States Patent THREAD SHEARING DEVICE Italo Della Bella, Saulheimer Str., and Bernhard Scholz, Gartner Str. 1, both of Worrstadt, Rhineland, Germany Filed Apr. 13, 1964, Ser. No. 359,355 Claims priority, application Italy, Apr. 12, 1963, 7,678/63 8 Claims. (Cl. 66-145) This application is a continuation-in-part of our copending application Ser. No. 202,014 filed June 12, 1962.

Our invention relates to a device for shearing off the loose threads on ladies stockings in circular knitting machines with a knife assembly consisting of, for example, a pair of knives each with two cutting edges and driven by electromagnetic or magnetic means, constituting a high-frequency vibrator, the assembly being displaced by means of a camming drum in accordance with the various operating phases required.

Hitherto known devices yielded good results regarding safety and reliability of operation, particularly a uniform and practically complete shearing of the loose threads, but had the disadvantage that if one or more needles accidentally failed to descend in the region of operation of the shearing device during the rotation of the needle cylinder, such needles would inevitably break as they hit the shearing knives thereby often damaging the latter.

It is, therefore, the object of the present invention to provide a safety device adapted to overcome this defect. According to the invention, the kinematic displacement means of the shearing device are provided with a spring element, extended into an operative position when the system of knives is pushed forward, and with a locking means maintaining the system of knives in an operative position as well as the spring element in its extended state. Furthermore there is provided a contact pin positioned in front of the system of knives responding upon contact with a needle and connected to a device for releasing locking means. The safety device according to the invention responds instantaneously as soon as a needle that has become caught in its upper position reaches the contact pin. The release device, which is connected with the contact pin, opens the lock instantaneously and the system of knives under the urging of the spring element immediately reverts from the region of the needle cylinder to its inoperative position Breaking of the needle and damage to the knives are thereby prevented. Another advantage of the safety device according to the invention resides in that it remains fully effective even when upon changeover to another yarn or for some other reason the needle cylinder and the needles of the circular knitting machine have been changed and the shearing device had to be readjusted with respect to the needle ring. Furthermore, the invention makes it possible to keep the system of knives near the needle ring so that loose threads can be shorn off very closely.

The invention will now be described more fully with reference to the accompanying drawing in which:

FIG. 1 is a top perspective view of part of .a circular knitting machine for ladies stockings where the shearing device according to the invention is to be disposed;

FIG. 2 is a perspective view of a shearing device with a safety device according to the invention;

FIG. 3 is a perspective view of the parts of the safety device; and

FIG. 4 is a perspective view similar to part of FIG. 2 showing a modification.

According to the drawing, a shearing device comprises a support 1 fixed to a platen 2, or to some other part of the frame of a circular knitting machine, and whose shearing knives 3 can be adjusted relatively to a needle cylinder 4 by means of one or more screws 5.

The shearing knives 3 move on a carriage 6 which, in turn, is guided on the support 1 to move in axial and radial directions to the needle cylinder 4. The carriage 6 is moved by a cable 7 against the action of a compression spring 8 mounted inside the support 1. This spring 8 is extended when the system of knives 3 moves toward the region of the needle cylinder 4 and is displaced outwardly as the knives 3 move radially away therefrom. The forward movement of the system of knives 3 into the region of the needle cylinder limited by an adjustment screw 9, is carried out as follows:

The cable 7 is covered by a sleeve 10 which resists axial pressure; the cable is connected to the support 1, which is fixed in position, while the cable sleeve 10 bears against a socket 12 mounted on an extension 11 of the carriage, thereby pushing the knives 3 forward into the region of the needle cylinder 4 by way of the carriage 6 and the extension 11 thereof.

In accordance with the invention, we provide a safety device for the system of knives 3 and the needle cylinder 4 which, on the one hand, causes the system of knives 3 to retract immediately from an operative to its inoperative position, i.e. out of the region of the needle cylinder 4, when a needle gets caught in the upper position and thus comes within operating range of the knives 3. On the other hand, the safety device according to the invention is designed to respond also when the system of knives 3, owing to incorrect adjustment of its displacement over the needle cylinder 4 or the platen 2, has been pushed forward into a region where the needles project at the top. An electromagnetic high-frequency vibrator means V is coupled with the blades 3 for relatively displacing same as described in our copending application mentioned above.

The safety device comprises, as a contacting and safety element, a contact pin 13 which projects over or in front of the system of knives 3. The contact pin 13 is held with freedom of axial displacement in a block 14 pivotable at 1411 on the carriage 6. Behind the block 14 are two

further blocks

15 and 16 clamped to the contact pin 13 by clamping screws 17. The contact pin 13 is slightly bent at 18 so that it can always be adjusted in any direction to the correct position with respect to the system of knives 3 by releasing the clamping screws 17 and axially displacing or rotating the .pin.

A guide pin 19 is fixed in the block 14. This guide pin extends parallel to the rear part of the contact pin 13 and carries a compression spring 20 behind the rear clamping block 16 bearing against the rear end of an adjustable socket 21. The two

clamping blocks

15 and 16 are slidably mounted on the guide pin 19 so that axial displacement of the contact pin 13 is transmitted to the compression spring 20 through the rear clamping block 16, this spring thereby maintaining the contact pin 13 in its forward position. The tension of the spring 20 can be adjusted by means of the socket 21.

The rearward clamping block 16 carries an actuating pin 22 threadingly engaging the block 16 so as to lie approximately parallel to the contact pin 13. Pin 22 is secured to block 16 by a nut as shown in FIG. 3. The actuating pin 22 is bent at 24. The position of the actuating pin 22 relative to the contact pin 13 can be adjusted as desired by changing the distance to which it is screwed into the block 16 and/ or by rotation.

The actuating pin 22 acts on a two-armed lever 26 by way of a transmission pin 25. The lever 26 is pivotally mounted at 27 on the carriage extension 11. The actuating lever 26 supports a locking roller 28 located ahead of the front end surface of the socket 12, so as to transmit the thrust exerted on the socket 12 by the cable sleeve 10 to the carriage extension 11 by way of the actuating lever 26. The socket 12 is provided, for this purpose, at its front end with a flange 29; an additional setting screw 30, fitted to the actuating lever 26, bears against the circumference of this flange to adjust the sensitivity of'response' of the device.

To limit the deflection of the contact pin 13, a stop pin 31 (FIGURE 2) is provided on the support 1 as well as an adjustable abutment 32 on the carriage 6. The reason for limiting the deflection of the contact pin 13 -is to ensure that during operation it will not swing into the region of the needle cylinder in which the needles project upwardly, where it might damage these needles.

During normal operation, to push the system of knives 3 into its operative position, the cable or core member 7, which isconnected to the support at 1, is pulled at the usual control plate of the machine so that the sleeve member of the control means exerts a thrust on the rear surface of the socket 12. This thrust is transmitted to the carriage extension 11 of the blade means by way of the locking roller 28, and from there to the carriage 6 and to the system of knives 3. The contact pin 13 participates in this forward displacement; a recess 33 in the block 16 abuts against the stop pin 31 so that, in the last part of the forward displacement, only the system of knives is pushed forwardly. When the pull on the cable 7 ceases, the spring 8 urges the carriage 6 with all the parts connected thereto, as well as the socket 12 and the cable sleeve 10 back into their original position. The main disturbances in operation that may occur are the following:

(1) By displacement of the support 1 relative to the platen 2, the knives 3 and the contact pin 13 are pushed forwardly into a region of the needle cylinder where the needles are raised or in an intermediate position.

(2) When a needle is damaged, it gets lodged in the upper position, i.e. in the region where the needles are cast off and would then slip into the knives 3.

In both cases, the safety device according to the. invention operates as follows:

As soon as the contact pin 13 comes into contact with a needle, the latter, rotating with the needle cylinder, causes the pin 13 to be deflected about its axis of swing 14a in the direction of the arrow 34 (FIG. 3). The actuating pin 22 of the release means thus presses against the transmission pin 25 and deflects the actuating lever 26 of the locking means so that the locking roller 28 is raised over the flange 29 of the socket 12, whereby the lock between the socket 12 and the carriage extension 11 is re-- leased. The carriage 6 is then free to move axially relatively to the socket 12 and is pushed back into its inoperative position by the spring 8. The knives 3 are thereby instantly pulled back from the region of the needle cylinder-4 before any needle can enter their operating range.

. By this axial displacement of the carriage 6 due to the spring 8, the carriage extension 11 is pushed into the socket 12. To reverse or eliminate this axial displacement, the cable 7 and its sleeve 10 are displaced relatively to each other so that they return to their original position, causing the locking roller 28 to run over the rear surface of the flange 29 and to become again located ahead of the front surface of the flange 29. It is advisable, for this purpose, to chamfer the rear surface of the flange 29 or at least make it enough so as not to cause any looking effect with respect to the radius of the locking roller 28. The setting of the locking roller 28 in its locking position is most easily achieved by keeping the actuating lever 26 constantly under the action of a spring permanently tending to swing the actuating lever 26 in a clockwise-direction, as seen in FIGS. 2 and 3.

To ensure that the locking roller 28 will respond to deflection of the contact pin 13, it is not necessary to lift the roller 28 completely over the flange 29, the radius which at that moment lies parallel to the direction in which the carriage extension 11 and the socket 12 are guided must be lifted over the outer edge of the flange 29 so that the roller can run over the flange. The deflec tion of the actuating lever 26 necessary for going beyond this critical position may be very small and can be adjusted accurately by means of the set-ting screw 30.

In the embodiment described above, the arrangement of the socket 12 of the cable 7 and the cable sleeve 10 is provided for a machine control in which the cable 7 is constantly under tension as long as the knives 3 are operative. It would also be possible to have machine controls before a pull is exerted on the cable 7 only for a short time only at the. beginning of the, shearing operation and is then immediately released. In such a system of machine control, the sleeve of the cable 7 may be disposed the socket 12 and bear against the rear end surface of the carriage extension 11. The socket 12,

like the support 1, is then fixed to an attached part of the machine frame. The roller 28 then' locks the carriage 6 and the system of knives 3 in their operative positions, while in the event of any danger'or disturbance the safety device instantly releases this lock from its operative position so that the carriage with the knives 3 can instantly jump back to the inoperative position. In such a modified construction, however, additional devices would be required to eliminate the locking of the roller 28 and of the

socket

12, 29 at the end of the shearing operation.

The above example has been described merely as one possible embodiment of the invention. Modifications of details can be visualized, which may, relate to the system of sleeves and sockets to enable the contact pin 13 to be moved axially. The arrangement of the spring and the locking system and their construction could also be modified.

What We claim is:

1'. In a shearing device for a circular knitting machine whereby loose threads are severed from a knit fabric, said device comprising blade means including at least one pair of relatively reciprocable knives having a pair of cutting edges relatively vibratable for shearing the loose threads upon the introduction thereof between the cutting edges of said knives, and control means operatively coupled with said blade means for positioning same in accordance with the operating conditions of the knitting machine, said blade means being displaceable by said control means between an operative position in which said knives. overlie the tips of the lowered needles of the knitting ma-' chine and an inoperative position in which the knives are disposed radially outwardly from said operative position, the improvement which comprises:

spring means stressable upon displacement of said blade means by said control means into said operative position and urging said blade means from said operative position toward said inoperative position; locking means releasably retaining said blade means in said operative position against the force of said spring means; a contact pin disposed in the region of said knives and engageable bya needle of the knitting machine; and release means operable by said contact pin for disengaging said locking means to permit said spring means to retract said blade means into said inoperative position. 2. The improvement defined in claim 1, further comprising a support fixed with respect to the knitting machine, said blade means including a carriage carrying said knives and generally radially displaceable on said support' relatively to said machine, said control means including a flexible cable having a sleeve member and a core mem-' said support, said carriage having an axially displaceable socket co-operating with said locking means.

' 3. The improvement defined in claim 2 wherein said I locking means comprises an actuating lever swingably mounted on said carriage between a locking position wherein said socket is retained against movement with said spring means stressed and a release position wherein displacement of said socket is permitted, a restoring spring resiliently retaining said lever in said locking position, said socket having a flange engageable by said lever for retaining said socket, and a locking roller rotatably mounted on said lever and cammable by said flange upon displacement of said socket upon the center of rotation of said roller clearing said flange.

4. The improvement defined in claim 3 wherein said socket is rigid with said carriage and said sleeve member is received within said socket while being axially displaceable relatively thereto and abuttable against said carriage for shifting same, said lever further comprising an adjusting screw engageable with said flange for regulating the distance by which said center of rotation of said roller must be displaced to clear said flange.

5. The improvement defined in claim 3 wherein said socket is rigid with said carriage and said sleeve member is rigid with said socket, said lever further comprising an adjusting screw engageable With said flange for regulating the distance by which said center of rotation of said roller must be displaced to clear said flange.

6. The improvement defined in claim 3 wherein said contact pin is swingable on said carriage and carries an actuating pin forming said release means, said actuating pin bearing against said lever, said lever having a transmission pin engageable by said actuating pin, said release means further comprising means for adjusting the position of said actuating pin relatively to said transmission pin.

7. The improvement defined in claim 6 wherein said contact pin lies generally in a horizontal plane and is axially displaceable upon said carriage, said carriage being further provided with an adjustable tension spring acting upon said contact pin for resistant axial displacement thereof.

8. The improvement defined in claim 2 wherein said contact pin is swingable substantially in a horizontal plane, said blade means further comprising adjustable abutment means on said carriage for limiting the deflection of said contact pin in one sense and a stop pin on said support for limiting deflection of said contact pin in the opposite sense, said stop pin engaging said contact pin for limiting displacement thereof relative to said support with said carriage toward said operative position.

References Cited by the Examiner UNITED STATES PATENTS DONALD W. PARKER, Primary Examiner.

Claims

1. IN A SHEARING DEVICE FOR A CIRCULAR KNITTING MACHINE WHEREBY LOOSE THREADY ARE SEVERED FROM A KNIT FABRIC, SAID DEVICE COMPRISING BALDE MEANS INCLUDING AT LEAST ONE PAIR OF RELATIVELY RECIPROCABLE KNIVES HAVING A PAIR OF CUTTING EDGES RELATIVELY VIBRATABLE FOR SHEARING THE LOOSE THREADS UPON THE INTRODUCTION THEREOF BETWEEN THE CUTTING EDGES OF SAID KNIVES, AND CONTROL MEANS OPERATIVELY COUPLED WITH SAID BLADE MEANS FOR POSITIONING SAME IN ACCORDANCE WITH THE OPERATING CONDITIONS OF THE KNITTING MACHINE, SAID BALDE MEANS BEING DISPLACEABLE BY SAID CONTROL MEANS BETWEEN AN OPERATIVE POSITION IN WHICH SAID KNIVES OVERLIE THE TIPS OF THE LOWERED NEEDLES OF THE KNITTING MACHINE AND AN INOPERATIVE POSITION IN WHICH THE KNIVES ARE DISPOSED RADIALLY OUTWARDLY FROM SAID OPERATIVE POSITION, THE IMPROVEMENT WHICH COMPRISES: SPRING MEANS STRESSABLE UPON DISPLACEMENT OF SAID BLADE MEANS BY SAID CONTROL MEANS INTO SAID OPERATIVE POSITION AND URGING SAID BLADE MEANS FROM SAID OPERATIVE POSITION TOWARD SAID INOPOERATIVE POSITION; LOCKING MEANS RELEASABLY RETAINING SAID BLADE MEANS IN SAID OPERATIVE POSITION AGAINST THE FORCE OF SAID SPRING MEANS; A CONTACT PIN DISPOSED IN THE REGION OF SAID KNIVES AND ENGAGEABLE BY A NEEDLE OF THE KNITTING MACHING; AND RELEASE MEANS OPERABLE BY SAID CONTACT PIN FOR DISENGAGING SAID LOCKING MEANS TO PERMIT SAID SPRING MEANS TO RETRACT SAID BLADE MEANS INTO SAID INOPERATIVE POSITION.