Improved selvedge forming mechanism, for forming a recessed selvedge in a fabric produced by means of a shuttleless loom

Abstract: A selvedge forming mechanism for forming a recessed selvedge in a fabric produced by means of a shuttleless loom comprises, in combinations: means for gripping and cutting the pick inserted inside the shed, a needle which captures the so-said "tail" of the cut pick and causes said tail to enter again, bent, the shed, which closes onto it realizing the recessed selvedge, and respective kinematic drive means for said gripping and cutting means, and for said needle. Said drive kinematic drive means comprise a first side carriage and a second side carriage, opposite to each other (15, 16) on which said gripping means (11) and cutting means (12) are installed, and a third, central carriage (26) on which said needle (13) is installed, said carriages (15, 16, 26) being driven to reciprocate by respective cams (18, 19, 28), which directly act on them, with the only interposition of a respective cam follower.

Description: The present invention relates to an improved selvedge forming mechanism, capable of forming a recessed selvedge in a fabric manufactured by means of a shuttleless loom. Selvedge forming mechanisms of this type are known, which comprise gripping means and cutting means for the pick inserted inside the shed, and a needle which captures the so-said "tail" of said cut pick, and causes it to enter again, in a bent configuration, into the shed, which closes onto it, thus realizing the recessed selvedge. Selvedge forming mechanisms of this type are well-known to those skilled in the art, and are disclosed and illustrated, e.g., in U.S. patents 3,951,177 and 4,076,049, to which the reader is referred, in case any clarifications are necessary. However, said selvedge forming mechanisms known from the prior art are only suitable for operating on looms operating with a relatively low revolution speed (rpm); in fact, difficulties arise when one tries to install said mechanisms on more modern looms, operating at very high revolution speeds, of round 600 rpm, and even more. The reason for this lack of adaptability of the selvedge forming mechanisms known from the prior art to very fast looms depends on the matter or fact that, in the selvedge forming mechanisms known from the prior art, the pick gripping/cutting means, as well as the needle, are driven by kinematic systems based on cams and levers which not only are very complex, but are also relatively cumbersome, and consequently uncapable of correctly operating at the required speeds. The general purpose of the instant invention is of obviating the drawbacks of the systems known from the prior art, by providing a very compact selvedge forming mechanism, in which the pick gripping/cutting means, and the needle, are driven by means of respective kinematic links based on cams and lever systems of very simple structure, and without the complex systems for operating connection with the motion source shaft. Said purpose is achieved according to the present invention by providing a selvedge forming mechanism for forming a recessed selvedge in a fabric manufactured on a shuttleless loom, of the type comprising, in combination: means for gripping and cutting the thread inserted inside the shed, a needle which captures the so-said "tail" of the cut pick and causes it to enter again, in a bent configuration, into the shed, which closes on it realizing the recessed selvedge, and respective kinematic drive means for said gripping/cutting means and for said needle, characterized in that said kinematic drive means comprise a first side carriage and a second side carriage, mutually opposite, (15, 16) on which said gripping means (11) and cutting means (12) are installed, and a third, central, carriage (26) on which said needle (13) is installed, said carriages (15, 16, 26) being driven to reciprocate by means of respective cams (18, 19, 28), which directly act on them, with the only interposition of a respective cam follower. The structural and functional characteristics of the invention, and the advantages thereof over the prior art will be understood in a still clearer way from the following disclosure, made by referring to the accompanying schematic drawings, which show an example of a form of practical embodiment of selvedge forming mechanism, constructed according to the principles of the same invention. In the drawings: Figures 1, 2 and 3 show transversal sectional, longitudinal sectional and top views respectively, illustrating the whole selvedge forming mechanism, in its non-operating position (i.e., in its cycle beginning position); Figures 4, 5 and 6 show transversal sectional, longitudinal sectional and top views respectively, illustrating the only gripper-scissors group of the selvedge forming mechanism, and the relevant kinematic drive means which drive it, in their non-operative position (i.e., in their cycle beginning position); Figures 7, 8 and 9 show transversal sectional, longitudinal sectional and top views respectively, illustrating the only needle of the selvedge forming mechanism, and the relevant kinematic drive means which drive the coming-out thereof, in their non-operative position (i.e., in their cycle beginning position); Figures 10, 11 and 12 show transversal sectional, longitudinal sectional and top views respectively, illustrating the only needle of the selvedge forming mechanism, and the relevant kinematic drive means which drive the rotation thereof, in their non-operative position (i.e., in their cycle beginning position); Figures 13, 14 and 15 show transversal sectional, longitudinal sectional and top views respectively, illustrating the whole selvedge forming mechanism, with the gripper-scissors group thereof being in a transient step of their coming out, and the needle thereof being in a transient step of coming out and of (zero) rotation of the same needle; Figures 16, 17 and 18 show transversal sectional, longitudinal sectional and top views respectively, illustrating the only gripper-scissors group of the selvedge forming mechanism, and the relevant kinematic drive means which drive it, during the transient step of its coming out as shown in figures 13, 14 and 15; Figures 19, 20 and 21 show transversal sectional, longitudinal sectional and top views respectively, illustrating the only needle of the selvedge forming mechanism, and the relevant kinematic drive means which drive it, during the transient step of needle coming out as shown in figures 13, 14 and 15; Figures 22, 23 and 24 show transversal sectional, longitudinal sectional and top views respectively, illustrating the only needle of the selvedge forming mechanism, and the relevant kinematic drive means which drive it, during the transient step of its rotation (zero) as shown in figures 13, 14 and 15; Figures 25, 26 and 27 show transversal sectional, longitudinal sectional and top views respectively, illustrating the whole selvedge forming mechanism with its gripper being in its end come-out and lowered position, and its needle being in its come out and rotated position; Figures 28, 29 and 30 show transversal sectional, longitudinal sectional and top views respectively, illustrating the only gripper-scissors group of the selvedge forming mechanism and the kinematic drive means which control it, in its end come-out and lowered position in order to perform the cutting of the weft by the scissors, and to enable the needle to grip the cut pick tail; Figures 31, 32 and 33 show transversal sectional, longitudinal sectional and top views respectively, illustrating the only needle of the selvedge forming mechanism, and the relevant kinematic drive means which drive it to come out, in their position shown in Figures 25, 26 and 27; and Figures 34, 35 and 36 show transversal sectional, longitudinal sectional and top views respectively, illustrating the only needle of the selvedge forming mechanism, and the relevant kinematic drive means which drive it to rotate, in their position shown in Figures 25, 26 and 27. Referring initially to Figures 1-3 of the accompanying drawings, the selvedge forming mechanism according to the present invention is generally indicated with the reference numeral 10, and is structurally formed by a gripper 11-scissors 12 group, a needle 13, and a plurality of kinematic drive means to drive them, contained inside a box or case 14. Referring to Figures 4-6 of the accompanying drawings, the gripper 11-scissors 12 group is installed on two side carriages 15, 16, which are driven to reciprocate in the directions of the arrow 17, by means of respective cams 18, 19, which typically directly act on the same carriages 15, 16, with the only interposition of a cam follower, as is explained later on. More precisely (Figures 4-6), said carriages 15, 16 comprise a chassis 20, 21, substantially having an "L"-shaped contour, fastened to guide rods 22, 23 slidingly installed on the case 14, as is clearly shown in the drawings. At the front ends of said guide rods 22, 23, the gripper 11-scissors 12 group is constrained. The cams 18, 19 act on respective rollers (cam followers) 24, 25 hinged onto the respective chassis 20, 21 of the carriages 15, 16. To secure the motion to take place at the high speeds required, with the cams 18, 19 conjugate cams 18a, 19a (integral with the cams 18, 19) cooperate, which act on respective rollers 24a, 25a hinged onto the chassis 20, 21. Referring to Figures 7-9, of the accompanying drawings, the needle 13 is installed on a central carriage 26, which is driven to reciprocate in the directions of the arrow 27, by means of a cam 28 directly acting on the same carriage 26, with the only interposition of a cam follower, as is explained in the following. More precisely, said carriage 26 comprises a chassis 29, substantially cradle-shaped, constrained to a bottom guide/drive rod 30, which is installed on the case 14, with possibility of translation and rotation, as is clearly explained in the drawings, and as is explained in greater detail in the following. The needle 13 is fastened onto the front end of the rod 30. With the lower rod 30 an upper rod 31 -- fastened to the case 14 -- cooperates. The carriage 26 reciprocates on said rod 31. The cam 28 acts on a roller 32 hinged onto the chassis 29 of the carriage 26. Also in this case, to secure the motion to take place at the required high speeds, with the cam 28 a conjugated cam 28a (integral with said cam 28) cooperates, which acts on a roller 32a hinged onto the chassis 29 of the carriage 26. Referring to figures 10-12 of the accompanying drawings, the rotation of the needle 13 is driven by a bell crank 33 hinged in 34 onto the case 14. The swinging of the bell crank 33 in the directions of the arrow 35 is driven by a cam 36 acting on a roller 37 hinged onto the same bell crank 33. A conjugated cam 36a (integral with the cam 36) acts on a roller 37a, also hinged onto said bell crank 33. The bell crank 33 is operatively linked with the lower rod 30, in order to drive said lower rod to rotate, by means of a shackle 38, which is hinged onto an end of same lever 33, and onto the opposite end of a radial arm 39 constrained to the rod 30 so as to be capable of rotating, but not of translating. The operating way of the selvedge forming mechanism according to the present invention will be clear from the above, as disclosed by referring to the drawings and, briefly, is as follows. The selvedge forming mechanism receives the motion in a per se known way from the main shaft of the loom on which said mechanism is installed; in fact, the shaft of the loom drives, through a suitable kinematic motion transmission link, the shaft schematically shown in 40, on which all the driving cams which actuate the selvedge forming mechanism are installed. Figures 1-12 show the selvedge forming mechanism in its resting position, at cycle beginning. The rotation of the driving cams 18, 19 and 28 causes the respective carriages 15, 16 and 26 to translate forwards, and to cause the gripper 11-scissors 12 group and the needle 23 to come out, to the position depicted in Figures 13, 14 and 15. During this transient step of coming out, the needle 13 does not rotate. Figures 16-18 show in detail the only movement of gripper 11-scissors 12 group coming out. Figures 19-21 show in detail the only movement of needle 13 coming out. Figures 22-24 show in detail the zero rotation of the needle 13. The gripper 11-scissors 12 group and the needle 13 complete their coming out movement in their position shown in Figures 25-27, and in this position the gripper 11 has also moved downwards to cause the pick to be cut, and the needle 13 has rotated in order to capture the "tail" of the cut pick, and to cause it to enter again, in a bent configuration, into the shed, which closes onto it. Figures 28-30 show in detail the end position of the only gripper 11-scissors 12 group, in its come-out and lowered position. Figures 31-33 show in detail the end position reached by the come out needle 13. Figures 34-36 show in detail the end position of the needle 13. The steps of moving down of the gripper 11, and of cutting of the pick by the scissors 12 are not shown herein in detail, in that said steps take place in a way per se known to those skilled in the art. Due to this reason, not even the structure of the gripper 11-scissors 12 group -- which does not fill within the scope of the present invention, and could be of any known types -- is illustrated in detail. By means of the above, the purpose declared in the preamble to the disclosure, of providing a selvedge forming mechanism, in which the means for gripping and cutting the pick, and the needle, are driven by means of an extremely simple kinematic drive link, with direct drive, i.e., without the presence of complex systems for operatively linking the motion supply shaft -- which cause errors to occur during the motion transmission, and do not enable high operating speeds to be reached, owing to the big masses required and of the several components which constitute the kinematic motion transmission link -- is thus achieved.

Claims: Selvedge forming mechanism for forming a recessed selvedge in a fabric manufactured on a shuttleless loom, of the type comprising, in combination: means for gripping (11) and cutting (12) the thread inserted inside the shed, a needle (13) which captures the so-said "tail" of the cut pick and causes it to enter again, in a bent configuration, into the shed, which closes on it realizing the recessed selvedge, and respective kinematic drive means for said gripping/cutting means and for said needle, characterized in that said kinematic drive means comprise a first side carriage and a second side carriage, mutually opposite, (15, 16) on which said gripping means (11) and cutting means (12) are installed, and a third, central, carriage (26) on which said needle (13) is installed, said carriages (15, 16, 26) being driven to reciprocate by means of respective cams (18, 19, 28), which directly act on them, with the only interposition of a respective cam follower (24, 25, 32). Selvedge forming mechanism according to claim 1, characterized in that said kinematic drive means additionally contain a drive lever (33) which drives the needle to rotate, also said lever (33) being centrally installed between the third carriage (26) and one of the side carriages (15, 16), and being driven to rotate by means of a cam (36). Selvedge forming mechanism according to claim 1, characterized in that said mutually opposite side carriages (15, 16) have a substantially "L"-shaped outline. Selvedge forming mechanism according to claim 1, characterized in that said central carriage (26) has a substantially cradle-like shape.

Inventors: NICOLINI ANTONIO, NICOLINI, ANTONIO
Applicants: CEM ITALIA SRL, CEM ITALIA S.R.L.
Application year: 1991
Main classification: D03D47
IPC codes: D03D47