Side-transfer device for flat knitting machines

Abstract: A side-transfer device for flat knitting machines, comprises, above and parallel to the needle bed which is opposite to the needle bed involved in the transfer, two smaller semi-needle beds (FT-FT′), each having a length which is half the length of the main needle bed, and spaced from each other, at their inner ends, by such an extent as to be longitudinally movable in and out to the maximum distance contemplated in the transfer step. Each semi-needle bed is provided with transfer fingers (7) spaced apart as the needles of the needle beds and in such a number as to serve half a needle bed. The longitudinal movements of said transfer fingers are controlled by a single auxiliary carriage (8). Each semi-needle bed (FT-FT′) is supported by a slide (4-4′) sliding on a guide (1) parallel to the needle beds of the machine, each slide being connected to means (17,18,19,20,17′,18′,19′,20′) which move it longitudinally for the transfer, rightwards, and leftwards. The guide (1), which also supports a guide for the auxiliary carriage (8), is connected to the frame of the machine so as to be pivotable about its longitudinal shaft (2) to enable, in an intermediate step, the transfer fingers (7) of the semi-needle beds to be raised and moved away from the needle beds in order to permit the transfer of the semi-needle beds to the extent required by the side transfer of the loops. The pivoting means comprises at least one respective lever (22-22′) pivotable on each end of a fulcrum shaft (2) and which may be locked to said shaft. The levers present, at their end, a respective roller (29-29′) which co-operates with a cam (30) carried by the carriage of the machine.

Description: This invention relates to a side-transfer device for flat knitting machines, which is particularly adapted to effect the automatic narrowing of the knitted fabric being manufactured, no matter whether it is of the type involving one or both the needle beds of the machine. The invention relates also to a new method for operating the automatic narrowing of the knitted fabric by utilizing the new side-transfer device. Document EP-A-0 103 033 discloses a side-transfer device for flat knitting machines, which comprises, parallelly and above the needle bed opposite to the needle bed involved in operation, an auxiliary and composite smaller needle bed containing independently movable transfer fingers equally spaced apart with the same spacing as the needles of said needle beds and in such a number as to serve all the needles of the needle bed which may be involved in the side transfer, said auxiliary smaller needle bed including two semi-needle beds which are identical, in line with each other and sufficiently spaced as to be able to move towards and away from each other during the transfer step, each semi-needle bed being mounted so as to be longitudinally slidable, through a respective slide, on a single guide, said guide being pivotable about its longitudinal axis, and means being provided whereby, under command, this pivotal movement is effected to raise and lower said semi-needle beds. In contrast to the present invention, this side-transfer device is equipped with transfer fingers comprising a flat spring and a single indentation. According to the invention, there is provided a side-transfer device of the above disclosed type, which is characterized by the fact that: a) said independently movable fingers comprise a front indentation and a rear indentation which is deeper than the said front indentation, and which registers with an indentation in a flat spring secured at its rear end to one side of the fingers, said fingers being controlled by a single auxiliary carriage mechanically connected to the machine carriage; b) said guide also carries the guide for the auxiliary carriage; and c) each slide is connected to a servo-control for being moved longitudinally either rightwards and leftwards. The side-transfer device according to the invention is further characterized by the fact that the means effecting the pivotal movement of the device comprise at least a respective lever which is mounted so as to be freely pivotable on the end portions of the longitudinal axis of said device, and comprises respective electro-magnets which, under command, will lock said levers to said shaft, said levers being provided at their ends with a roller arranged on the path of travel of a cam associated with the machine carriage, the arrangement being such that when said auxiliary smaller needle bed is to be raised, said levers are locked on the shaft mounting them, whereas in the contrary case said levers are freely pivotable on said shaft, said cam being so shaped as to act on said levers at the end of either the rightwards and the leftwards stroke of the machine carriage. Further characteristics of the invention and the advantages resulting therefrom will be more apparent from the following description of a preferred embodiment thereof, shown by way of a non-limiting example in the figures of the accompanying sheets of drawings, wherein: Fig. 1 is a side and partly sectional view of the device in the rest position; Fig. 2 is a diagrammatic top plan view of the device, the auxiliary carriage and the fingers being omitted; Fig. 2a is a diagrammatic perspective view of one of the end portions of the device, provided with a pitching control; Figs. 4,5,6,7,8,9,10,11,12,13,14,15,16 are side views of the operating portions of the device according to the invention and of the knitting machine, during as many significant steps of the side-transfer cycle. With reference to fig. 1, FA and FP indicate the front and the rear needle beds, respectively, of a flat knitting machine, which are provided, preferably, with transfer needles A1 and A2 which, according to a conventional technique, permit to carry out a narrowing operation by acting only on the needles of either one of the two needle beds (for example, on the needles of the needle bed FA) regardless of whether the fabric being knitted concerns one or both said needle beds. According to the invention, the transfer device is arranged, for example, above the needle bed FP and comprises a guide bed 1 which is parallel to said needle bed, it has substantially the same length as said needle bed and is fulcrumed, at least at the ends thereof, at 2, on supports 3 which, in turn, are secured to the frame of the machine. The fulcrum 2 is parallel to 1 and to the needle bed FA. Mounted parallelly beside said fulcrum 2 so as to be movable longitudinally, are composite slides 4-4′ supporting longitudinally and overhangingly the beds 5-5′ of the two side-transfer smaller semi-needle beds FT-FT′, which rest by gravity, through their adjustable portions 6, on the frame on the rear needle bed FP. The bed 5-5′ of the smaller needle beds FT-FT′ is half the length of the needle bed FA of the machine and is formed with transverse equally spaced apart grooves having the same spacing or pitch as the needles of the needle beds FA-FP and slidably supporting therein the narrowing fingers 7, which are formed with a respective butt cooperatively engageable by a small carriage 8 to be discussed below, provided with cams or triangles which may be either activated or disactivated in a conventional manner in order to selectively displace said fingers longitudinally as discussed below. In fig. 2 it can be seen that the inner ends of said smaller semi-needle beds FT-FT′ are spaced apart at the minimum distance permitting the longitudinal displacements of said semi-needle beds during the transfer step, as described in the Italian patent N o 1.146.466 of July 1, 1981 and in the Italian patent application N o 12650 A/84 in the name of the same applicant. When the transfer device is in its rest position as shown in fig. 1, said fingers 7 are completely retracted in their guide seats, so as to avoid interfering with the movement of the needles in the machine needle beds. However, said fingers 7 are already oriented as required to carry out the first steps of the operating cycle pertaining to them (see below). As best shown in the detail of fig. 4, the fingers 7 present a substantially known shape and comprise a front indentation 9 and a rear indentation 10 deeper that the former and registering with a slot which is formed at one side of said finger, in a flat spring 11 secured in a conventional manner at its rear end to one side of said finger. In fig. 1, it will be noted that the carriage 8 is supported by a structure 12 which, through grooved wheels 13, moves on a guide 14 which is secured longitudinally to the guide 1 with the interposition of spacer 15. Provided on the top and intermediate section of the structure 12 there is a fork-like member 16 for the mechanical connection with the carriage of the machine through means permitting the device to pivot freely about the fulcrum 2. In figs. 1 and 2, it will be noted that the outer end of each slide 4-4′ has secured thereto a support 17-17′ carrying a nut member co-operating with a screw member 18-18′ which is connected through a shaft 19-19′ to a reversible motor unit 20-20′ which, in turn, is rotated by a support 21-21′ so arranged as to be pivotable on the fulcrum 2. With reference also to fig. 3, it will be noted that pivotably and normally mounted on the ends of the fulcrum shaft 2 are respective levers 22-22′ each of which is urged upwards by a resilient means 31 and is formed with a hole 23 parallel to said shaft 2 in one side thereof. When the lever 22 is in its rest position, the hole 23 is aligned with or slightly above a lock bolt 24 which is movable in a hole 25 formed in a body 26 keyed to the shaft 2 and mounting an electro-magnet 27 whose movable member is connected to said bolt 24 and to an opposing spring 28 which usually keeps said bolt in a retracted position within its seat 25. The lock bolt 24 is sized and arranged so that when the electro-magnet 27 is energized and the lever 22 is pivoted downwards, said lock bolt engages the hole 23 and locks said lever 22 to the shaft 2, whereby the smaller needle beds FT-FT′ are pivoted about the shaft 2 (see below) and are raised. A similar servo-control 27′ is provided to lock, if desired, also the lever 22′ to the shaft 2. It will be noted in the figures 1,2 and 2a that each lever 22-22′ mounts at an end thereof an idle roller 29-29′ arranged on the rectilinear path of travel of a rectilinear cam 30 associated with the main frame of the machine and shaped at both ends thereof as shown in fig. 2a, so as to operatively act on the lever 22 and on the lever 22′ during the rightward and leftward displacements of the machine carriage. The device disclosed above operates as follows: At the beginning of each transfer cycle, the auxiliary smaller needle beds FT-FT′ are arranged with their inner ends at the maximum distance from each other if, obviously, the transfer is supposed to effect a decrease in the operating needles of the machine. While the machine carriage and the auxiliary carriage 8 reach the operative needles of said machine, conventional means will raise (fig. 4) the active end needles A of the needle bed FA that are to be loaded with the respective stitch-loops B. The loops B slide by gravity on said needles A and will abut against a step G having at one side thereof a slot defined by a thin plate L, as specified above in connection with the narrowing fingers 7. Due to the raising of said needles A, the loops B thereon are centered with respect to as many fingers 7 which, by the action of the activated carriage 8, are extended longitudinally from the smaller needle bed FT, as from fig. 5, whereby their tips will enter said loops B. Thereafter, as shown in the sequence of figs. 6 and 7, the needles A are lowered while the activated fingers 7 are slightly retracted and then extended again, whereby the latch of each said needles A will suitably interfere with said loops B to be closed thereby, while said loops will be kept in the front indentation 9 of said fingers, as shown in fig. 8. From fig. 9, it can be seen that upon completion of the lowering movement of the needles A, the fingers 7 are over-extended so that the loops B will move from the front indentation 9 into the rear deeper indentation 10, whereafter said fingers are retracted back to their previous position (see also fig. 10). When the machine carriage moves away from the operation area (see figs. 2, 2a) and said operations have been carried out at one or both selvages of the knitted fabric, the cam 30 engages, for example, the roller 29 of the lever 22 and the latter is locked to the shaft 2 due to the programmed action of the electro-magnet 27. The device is pivoted about the shaft 2 and causes the lifting movement of said auxiliary smaller needle beds FT-FT′ to such an extent whereby the fingers 7 loaded with the loops B will disengage from the top portion of the machine needle beds. The drive units 20-20′ are now activated and move the smaller needle beds FT-FT′ longitudinally towards the centre of the machine, each by the extent required by the transfer step. On completion of the transfer, the machine carriage starts the next operative stroke and the cam 30 disengages from the roller 29, so that the auxiliary smaller needle beds FT-FT′ are returned to their initial lower position. When the carriage 8 reaches the activated fingers 7, it makes them over-extended, as from fig. 11; thereafter, while the needles A′ designed to receive the loops B are raised, said fingers 7 are retracted as viewed in the sequence of figs. 11 and 12, so that the latch of the needles A′ will be clamped sideways between the flat spring 11 and one side of said fingers 7. Immediately thereafter, the fingers 7 are extended again, as from fig. 13, so that simultaneously with the lifting movement of the needles A′ the following two conditions occur; the latches of the needles A′ will be opened; the needles A′ will enter the side slot of said fingers and, therefore, the loops B carried thereby, as shown also in fig. 14. The needles A′ are then lowered again, while at due time the fingers 7 are retracted into the respective auxiliary smaller needle beds FT-FT′, as shown in the sequence of figures 15 and 16. The loops B remain on the needles A′, which in their descent will be closed due to the co-operation between their latches with conventional means. Successively, by the action of the respective driving units 20-20′, the smaller needle beds FT-FT′ are moved again to the most spaced apart position and are ready for repeating a new operative cycle. It is apparent that with the device of the invention the transfer of the loops on both selvedges of the fabric being knitted may be carried out during only two strokes of the machine carriage, and that these strokes may start, indifferently, from the right-hand or left-hand side.

Claims: A side-transfer device for flat knitting machines, of the type comprising, parallelly and above the needle bed (FP) opposite to the needle bed (FA) involved in operation, an auxiliary and composite smaller needle bed (FT-FT') containing independently movable transfer fingers (7) equally spaced apart with the same spacing as the needles (A1,A2) of said needle beds and in such a number as to serve all the needles (A,A') of the needle bed which may be involved in the side transfer, said auxiliary smaller needle bed including two semi-needle beds (FT,FT') which are identical, in line with each other and sufficiently spaced as to be able to move towards and away from each other during the transfer step, each semi-needle bed being mounted so as to be longitudinally slidable, through a respective slide (4-4'), on a single guide (1), said guide (1) being pivotable about its longitudinal axis (2), and means (22,27,30) being provided whereby, under command, this pivotal movement is effected to raise and lower said semi-needle beds (FT,FT'), characterized by the fact that a) said independently movable fingers (7) comprise a front indentation (9) and a rear indentation (10) which is deeper than the said front indentation (9): and which registers with an indentation in a flat spring (11) secured at its rear end to one side of the fingers (7), said fingers being controlled by a single auxiliary carriage (8) mechanically connected to the machine carriage; b) said guide (1) also carries the guide (14) for the auxiliary carriage; and c) each slide (4, 4') is connected to a servo-control (17,18,19,20,17',18',19',20') for being moved longitudinally either rightwards and leftwards. A device according to claim 1, characterized by the fact that the means effecting the pivotal movement of said device comprise at least a respective lever (22-22') which is mounted so as to be freely pivotable on the end portions of the longitudinal fulcrum axis (2) of said device, and comprises respective electro-magnets (27-27') which, under command, will lock said levers to said shaft, said levers being provided at their ends with a roller (29-29') arranged on the path of travel of a cam (30) associated with the machine carriage, the arrangement being such that when said auxiliary smaller needle bed is to be raised, said levers are locked on the shaft mounting them, whereas in the contrary case said levers are freely pivotable on said shaft, said cam being so shaped as to act on said levers at the end of either the rightwards and the leftwards stroke of the machine carriage. A method for the side-tranfer of loops to effect the automatic narrowing of the knitted fabric being manufactured in flat knitting machines according to claim 1 comprising in combination the following steps: a) the independently movable transfer fingers involved in the side transfer are extended and their tips enter the loops (B) to be transferred, which have been suitably raised and positioned by the respective transfer needles (A) of the machine; b) the fingers loaded with the loops are over-extended so that said loops will engage the rear indentation (10) of said fingers, whereafter said fingers are moved back to their previous position; c) the semi-needle beds containing the transfer fingers are raised from the needle beds of the machine, are subsequently displaced longitudinally by the extent required for the transfer and are then lowered again to the previous position; d) the machine needles designed to receive the loops are raised, e) the transfer fingers are retracted back to their rest position, while the needles are lowered to carry said loops (B) therewith and are closed due to the co-operation of their latches with conventional means, the arrangement being such that before a new transfer cycle is repeated said semi-needle beds (FT-FT') will be returned automatically to their initial position, with a longitudinal movement contrary to the longitudinal movement effected previously in the active operating step, characterized by the fact that prior to step b) while the needles of the machine are lowered again, the fingers supporting said loops are first retracted by a small amount and then are extended again, so that said loops will co-operate with the latches of the needles to close them; and that during step d) the loaded fingers are over-extended and then are retracted and thereafter are extended again while, at due time, in such a manner that the latches of said needles will be clamped and opened during the predetermined relative displacement between the system of fingers with respective side spring and said needles which enter the loops carried by the fingers; .

Inventors: BERNARDELLI GIANCARLO, BERNARDELLI, GIANCARLO
Applicants: MARTINELLI COMET SRL, COMET MARTINELLI S.R.L.
Application year: 1988
Main classification: D04B7
IPC codes: D04B15, D04B7