PILOTELLI, Roberto (Via Roma, 102, lseo, I-25049, IT)
PILOTELLI, Renato (Via Campo 36, lseo BS), I-25049, IT)
PILOTELLI, Roberto (Via Roma, 102, lseo, I-25049, IT)
| Claims 1. A single cylinder weft knitting machine comprising a cylinder (1) with needles (3); a plurality of feeds; a common annular support (7) for thread guides (5) of said feeds, each thread guide comprising a latch- opening cam (11); characterized by comprising guiding means (21 , 23, 25A, 27) and controlling means (31) for guiding and controlling said common support (7), so as to allow an extemporaneous displacement thereof together with the thread guides (5) carried by said common support, so as to move said latch-opening cams (11) of the needles from a normal working position to a withdrawn position with respect to the path of the latches (3A) and to maintain the threads fed by each thread guide (5) engaged by the needles (3). 2. A machine as claimed in claim 1 , characterized in that said annular support (7) of the thread guides (5) comprises a plurality of segments (25A) of cylindrical surface coaxial to the cylinder (1) of the needles (3), the segments (25A) being distributed around the support (7) and being each in contact with a respective radial support element (27) integral with the frame (19) of the machine, so as to allow a limited rotation and axial translation of the annular support (7) relative to said frame. 3. A machine as claimed in one or more of claims 1 or 2, characterized in that said annular support (7) of the thread guides (5) comprises a plurality of cams (21) distributed along the lower surface thereof, suitable to make the annular support (7) to follow said displacement between the working position and the withdrawn position of the thread guides (5) and of the corresponding latch-opening cams (11) when the support (7) is rotated between two preset angular abutments (26) with respect to the frame (19) of the machine. 4. A machine as claimed in claim 3, characterized in that each cam (21) cooperates with a respective support ferrule (23) integral with the frame of the machine, and in that elastic load means (16, 16A, 16B) are provided in order to maintain the annular support (7) pressed with a preset force against said ferrules (23). 5. A machine as claimed in one or more of claims 2 to 4, characterized in that said radial support element (27) for each segment (25A) of cylindrical surface of the annular support (7) is a radially adjustable screw ferrule, so as to facilitate, during installation, the centering of the annular support (7) with respect to the needle cylinder (1). 6. A machine as claimed in one or more of claims 2 to 5, characterized in that each of said cylindrical centering surfaces (25A) is provided on a link (25) applied inside said annular support (7), the link (25) having fixing radial bases (25B) having reduced bulk along the periphery of the annular support (7), each of which is arranged between two adjacent thread guides (5) and is fixed to the annular support (7). 7. A machine as claimed in one or more of claims 2 to 6, characterized in that said radial support elements (27) for the annular support (7) are fixed to the frame of the machine, each by means of a respective radial bracket (29) which extends beyond the annular support (7) and which has a limited lateral thickness, so as not to hinder the passage of the threads. 8. A machine as claimed in one or more of the previous claims, characterized in that from the annular support (7) of the thread guides (5) a vertical pivot pin (37) projects, and in that a lever (31) with a handle is hinged to the frame of the machine, parallel to the axis (X-X) of the annular support (7), an end of which has a recess (31D) engaged with said pivot pin (37) so as to allow the manual rotation, with limited effort, of said support (7) and of all the thread guides (5) of the machine between said two positions, respectively the working position and the withdrawn position. 9. A machine as claimed in claim 8, characterized in that said lever (31), in the part of the handle, is divided into two segments (31 B, 31C) hinged to each other at a pivot pin (35) so as to reduce the radial bulk thereof when not in use. 10. Process to facilitate the work during the phases of start of a new piece or of resumption of work following the breakage of a thread in a single cylinder weft knitting machine, characterized in that, through guiding means and controlling means according to one or more of the previous claims, the thread guides (5) of the machine are extemporaneously displaced in a position in which the respective latch-opening cams (11) are withdrawn from the trajectory of the latches (3) of the needles and the corresponding threads fed by the thread guides (5) continue to be engaged with the needles, so as to allow the rotation of the cylinder (1) without breakage of needles and without fall of work during setting and knitting operations of the machine. |
DESCRIPTION
Technical field
The present invention relates to a single cylinder weft knitting machine, in particular to a machine having a plurality of feeds.
State of the Art
The known machines of the cited type use generally latch needles and, to maximize productivity, are provided with a high number of thread feeds. When work of a new piece starts, and therefore all the needles of the machine are still devoid of thread, or when - due to the breakage or the exhaustion of a thread - the produced fabric has been left by at least one group of adjacent needles, the latches of the needles devoid of thread, no longer controlled in their rotation by the last row of stitches formed, can impact on the thread guiding members that are on their trajectory, for example the parts of thread guide acting as control cams for controlling the latches of the needles, below called "latch-opening cams", thus damaging themselves and needing long manual interventions for replacing the damaged needles and make all the feeds of the machine start working again. Objects and Summary of the invention
An object of the present invention is to alleviate substantially the drawbacks described above in the use of a single cylinder weft knitting machine having a multiplicity of feeds and comprising a common annular support for the thread guides of the various feeds.
According to the present invention, the machine comprises guiding and controlling means for guiding and controlling said common support of the thread guides, to allow extemporarily a displacement to bring the thread guides, in particular the latch opening cams of the needles, from a normal working position to a position withdrawn from the path of the latches. Furthermore, this displacement is performed so as to move the holes (and/or any guiding slit) of the thread guides according to such a direction as to maintain the threads engaged to the needles, so as to allow the operator to perform rotations of the cylinder with reduced speed for setting up the knitting without the risk of breaking needles and losing work. Brief description of the drawings
Various characteristic embodiments of the present invention are indicated in the appended claims and will be more apparent from the description below and the accompanying drawings, in which:
figure 1 is a sectional view, according to a plane containing the axis of the cylinder of the needles, of the upper part of the cylinder and of the thread guides-supporting structure in a circular knitting machine according to the invention;
figure 2 is a plan view according to H-Il in figure 1 ;
figure 3 is a plan view in reduced scale of the annular support fitted with the thread guides and the corresponding support and control members of the circular knitting machine of figure 1 ;
figure 4 is an elevation sectional view according to IV-IV of figure 1 ; figure 5 is an enlarged view of the detail V of figure 3;
figure 6 is an elevation sectional view according to Vl-Vl of figure 5; figure 7 is an elevation sectional view according to VII-VII of figure 5; figure 8 is an enlarged elevation view according to VIII-VIII of figure 1, showing a thread guide of the machine in two positions, a working position (continuous line) and a withdrawn position (dotted line).
Detailed description of embodiments of the invention
Referring first to figure 1, the invention relates to a circular knitting machine comprising a cylinder 1 rotatable around a vertical axis X-X carrying needles 3 with latch 3A slidable according to generatrixes of the cylinder in channels 1A provided on periphery thereof. The machine comprises a plurality of thread feeds distributed uniformly along the periphery of the cylinder, each of which comprises actuating cams (not shown in the drawing) for the needles and a thread guide 5, according to a well known arrangement. The thread guides 5 of the various thread feeds are carried by an annular support 7 coaxial with the cylinder 1 and supported through uprights 15 by the fixed frame 19 of the machine. In the upper surface of the annular support 7 a plurality of radial notches 7A (figure 2) is provided, mostly distributed uniformly on the periphery of the support 7. In each notch 7A a single thread guide 5 is fixed by means of a screw 9 (for the sake of simplicity in the drawing, in figures 1 , 2, and 3 only one thread guide 5 is shown applied to the support 7).
As known, each thread guide 5 comprises a latch-opening cam 11 near the needles 3 in each feed, said cam having a profile 11A (figure 8) suitable to ensure opening of the latches of the needles that must take one or more threads from specific holes or guiding slits 13 of the thread guide 5, as illustrated in the part shown with solid line in figure 8, wherein the line (a) indicates the path of the upper end of the needles at a feed and F indicates the direction of rotation of the cylinder.
According to the invention, the annular support 7 of the thread guides
5 is supported by the frame 19 of the machine so as to allow it a limited rotation around its own axis X-X (figure 3) and a limited vertical movement according to said axis, as will be better described hereunder. In particular, the annular support 7 is supported for example by five of the uprights 15 distributed along the periphery of the support and fixed by means of screws 17 (see also figure 1) to the frame 19 of the machine. In correspondence of each upright 15, to the lower surface of the annular support 7 of the thread guides a cam 21 is fixed (figure 4) which rests on the upright 15 by means of a vertical ferrule 23. This latter can be adjusted in height by means of washers 21 B and it can be fixed in position by means of a bolt 23A.
Usually this type of machines has a large number of feeds, for example 100 or more, and, as for each feed more threads are used, for example 2, it must be avoided that the supporting and moving members of the annular support 7 interfere with the thread guides 5 and with the passage of the threads. For this reason, in correspondence of the uprights 15 and inside the annular support 7, links 25 (figures 1, 2, 3, 5) are fixed, whose surface 25A facing the centre of the annular support 7 is cylindrical and coaxial with the cylinder 1 of the machine. The links 25 are fixed to the annular support 7 by means of narrow radial extensions 25B (figure 5), each of which can be inserted in the narrow space existing between two adjacent thread guides 5.
For each link 25, a threaded horizontal ferrule 27 (figure 1) is screwed to the free end of an arched radial bracket 29 of reduced thickness and - A - integral with the upright 15 and fixed there with a lock nut 27A, an end of each ferrule resting with minimum clearance on the cylindrical surface 25A of a respective link 25. In correspondence of one of these uprights 15 (figures 5, 6, and 7) two adjustable abutments are provided, suitable to define the angular travel of the annular support 7. These abutments are formed by screws 26 screwed, in correspondence of a slot 7C, in respective holes of a projecting part 7B of one of the cams 21, so as to act as a stop for a pin 16 fixed at the upright 15. On the pin 16 a compression spring 16A is inserted, acting between the head of the pin and a washer 16B to bias the annular support with its cams 21 such as to rest against the ferrules 23.
In this way the annular support 7 together with all the thread guides 5 can be rotated between the abutments 26 so that, following the profile of the cams 21, it moves with a nearly helicoidally motion with respect to the frame 19 of the machine. This movement is obtained manually by an operator through a lever 31 (figures 1 and 2) provided with a handgrip 31 A and pivoted to an upright 15 by means of a pin 33 with a vertical axis. The lever 31 comprises two segments 31 B, 31 C hinged to each other through a pin 35 with a horizontal axis, so as to take an arrangement with a reduced lateral bulk when it is not in use. The segment 31 C of the lever, at the end opposite to that with the pin 35, has a frame inside which a pin 37 is housed, fixed to one of the cams 21 and in turn integral with the annular support 7 of the thread guides 5. The length of the arms of the lever are such as to substantially reduce the manual stress necessary for the movement of rotation and lifting of the annular support 7.
The cams 21 resting on the ferrules 23 have an inclined surface 21A
(figure 4) so that, by rotating the annular support 7 around the axis X-X through the lever 31, said support follows such an helicoidal motion around the axis X-X of the cylinder 1 that the latch-opening cams 11 of the various thread guides 5 can be moved from a position shown with a solid line in figure 8, wherein the cam is adjacent to the path (a) of the needles 3 going upwards to take the threads fed through the guiding slits 13, to a position shown with a dotted line in figure 8 again, wherein the latch-opening cams 11 are completely cleared from the path of said needles 3 following the path (a) and therefore do not interfere with their latches 3A. Furthermore, the thread segments from the guiding slits 13 of the thread guide 5 to the stitch forming point (P) rest with the part under the beard of the needles so that, by rotating the cylinder 1, the needles continue to form stitches regularly, and it is possible to perform control and other operations (such as to replace a broken thread or a broken needle, or other), even if with a limited speed, without risks of folding or breaking the latches, thus significantly simplifying the work with respect to known machines.
It is understood that the drawing only shows an example provided by way of a practical demonstration of the present invention, which can vary in forms and arrangements without however departing from the scope of the concept underlying the invention. Any reference numbers in the appended claims are provided for the sole purpose of facilitating reading of the claims in the light of the description and the drawing, and do not in any manner limit the scope of protection represented by the claims.