FIELD OF THE INVENTION

The present invention relates to an improved setting apparatus of a textile spinning preparatory process. Particularly the invention related to a nipper gauge setting apparatus used in a textile combing machine. More particularly the invention relates to an improved device for precisely adjusting the distance between nippers and detaching rollers in a combing machine.

BACKGROUND OF THE INVENTION A known textile fibre combing machine comprises a plurality of combing heads in which the elements like combing cylinder, a nipper apparatus, a top comb and a pair of detaching rollers are being mounted. During combing operation, the fibre web is being combed by the rotating combing cylinder in order to remove the short fibres from it. The combers of these type having an oscillating nipper shaft for oscillating the nipper apparatus adjacent to a rotary combing cylinder, the so- called half-lap, and to a top comb, toward and away from a pair of detaching rollers in order intermittently to feed and comb the fibers of a lap having long been known in the textile art. Heretofore, such combers have been subject to a number of deficiencies, mostly resulting from their mechanical complication. Thus, they were not only difficult to set up, but also as to the unwanted high percentage of noil produced. Noil is the waste fibres that are being removed from fibre web during combing operation. Depending upon the staple length of the processing fibres, the percentage of noil removal can be fixed. Said noil quantity can be adjusted by varying the detaching distance i.e., the distance between nipping point of nipper arrangement and the nipping point of pair of detaching rollers (such distance is referred as the "nipper gauge"). To increase the noil percentage, the nipper gauge is made larger, whereas, to decrease the noil percentage, the nipper gauge is made smaller. To adjust the nipper gauge, the relative angular position of the drive coupling and nipper shaft is to be changed. For changing the nipper gauge (the front reversal point of nipper), the bolts on the drive coupling is loosened and the nipper shaft is to be rotated. After ensuring the desired detaching distance the bolts on the coupling is to be tightened. In said technology, for adjusting the nipper gauge the setting screws are provided with coarser pitch thread in which one revolution of the setting screw results higher (around 2mm) variation of detaching distance.

In aforesaid case, controlling the movement within one revolution of screw is difficult; either it will move more or lesser than the required amount. So now the users are doing the setting in trial and error method. Since the setting adjustment place and checking points are apart, considerable operative efforts are required. The finer pitch threads cannot be the solution because of its lower load carrying capacity and life.

An attempt was made to increase the user friendliness in the Indian patent IN231262 of MASCHINENFABRIK RIETER AG by providing the vernier kind of scale. But in this arrangement also, the threads are coarser and hence the finer controlled movement is difficult. And also the absence of additional finer adjustment provision of vernier makes more difficult while finer setting requirements. Because of these limitations, the precised and effective control on noil removal is quite complicated one. OBJECTS OF THE INVENTION

The primary object of the present invention is to provide an improved setting device in a combing apparatus which would give more precised nipper gauge setting.

One more object of the present invention is to provide a improved setting device with simplified constructions and quickly arriving the precised setting, Yet another object of the present invention is to provide a user-friendly nipper gauge setting apparatus which requires less man hour for setting and reduced operative effort.

SUMMARY OF THE INVENTION

The present invention related to an improved nipper gauge setting apparatus for a textile combing machine. In order to overcome the aforesaid difficulties of existing art, the present invention provides a nipper gauge setting apparatus, comprising: a nipper shaft; a setting bar firmly held at an end of the nipper shaft through at least one fastening means; wherein the said apparatus is provided with atleast one differential screw arrangement. For rotating the nipper shaft with respect to the coupling, a differential screw arrangement with two different kind of thread pitches is proposed in nipper gauge setting apparatus. Even with coarser thread, finer variation of (approximately around 0.25mm) detaching distance can be achieved with lesser effort. The apparatus comprises a two different kind of thread pitches, in which both of them is coarser in setting screw or setting nut or in both. Since these two different kind of pitch threads are moved with respect to one another, it is possible to set the nipper gauge with fine adjustments and thereby the accurate setting can be achieved with very less effort. Accordingly, an aspect of the present invention is to provide a differential screw nipper gauge setting apparatus, comprising a nipper shaft, a setting bar firmly held at an end of the nipper shaft through at least one fastening means, first self aligning member has internal thread for adopting threads of a first screw means of a stud member, wherein the first self aligning member is hinged on one side of the setting bar apart from the axis of fastening means and a second self aligning member has internal thread for adopting threads of a second screw means of other side of a stud member, wherein the second self aligning member is screwed into the threads to hinge on a slit bracket, wherein through the nipper gauge setting, for one full revolution of the stud member, the stud member moves a predetermined distance with respect to the second self aligning member, and for the same revolution of first screw means the first self aligning member moves a predetermined distance relatively.

In another aspect of the present invention is to provide a differential screw nipper gauge setting apparatus, comprising: a nipper shaft, a setting bar firmly held at an end of the nipper shaft through at least one fastening means and a pair of screw means are positioned in the internal bores of "T" studs, wherein the first end of screws are flattened to allow linear movement without rotation and the second end of screws are provided with a pair of differential nut fasteners, wherein through the nipper gauge setting, the differential nut fastener is rotated for one full revolution, the screw means is screwed to push a stopper bush triggers the setting bar to get a curvilinear movement away with respect to the stopper bush, which further triggers the nipper shaft to get an angular displacement along the setting bar to obtain a required nipper gauge setting.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

Fig-1 is the isometric view of the headstock of the typical combing machine, wherein a combing unit and the setting apparatus which relates to the invention is shown. Fig-2 is the schematic representation of the combing unit which shows the detaching distance i.e., the nipper gauge. Fig-3 illustrates the improved nipper gauge setting apparatus according to the invention.

Fig-4 schematically represents the alternate embodiment of the nipper gauge setting apparatus according to the invention.

Fig-4a schematically represents the top view of the present invention as well as the differential nut fastener provided in the alternate embodiment of the invention. Fig-5 illustrates the top view of the embodiment shown in Fig-4 according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION The typical combing machine with a combing unit (1) and nipper gauge setting apparatus (2) is shown in Fig-1 of the drawings. For example a single combing unit (1) of the machine is shown instead of plurality of combing units. The driving arrangement for several combing unit (1) is provided at the headstock (3) of the machine wherein a nipper gauge setting apparatus (2) is provided for the entire plurality of combing units. In Fig-2 of the drawings, the combing unit (1) is shown wherein the pair of detaching rollers (7), nipper arrangement (8) and the detaching distance or nipper gauge (D) are clearly illustrated. The nipper gauge (D) is the distance between nipping point of pair of detaching rollers (7) and the nipping point of nipper arrangement (8). Since the circular comb shaft (5) and nipper shaft (6) are synchronously connected with each other through a slider crank mechanism (4), the nipper arrangement (8) can be adjusted while nipper gauge setting.

According to the one aspect of the present invention, the differential screw nipper gauge setting apparatus (2) is illustrated in Fig-3 of the drawings. The differential screw nipper gauge setting apparatus (2) is rigidly mounted at headstock end of the nipper shaft (6) which is mounted with a slit bracket assembly (9a, 9b). Said slit bracket assembly (9a, 9b) comprises a three pair of screws (10a, 10b and another one is not shown) for tightening and loosening them over the nipper shaft (6), while setting the nipper gauge (D), the screws (10a, 10b) are being loosened and after adjusting the nipper gauge they have been tightened in their position. The coaxial rotational adjustment (relative angular displacement) of the nipper shaft (6) with respect to slit bracket assembly (9a, 9b) and slider crank (4) is meant for nipper gauge setting. The differential screw nipper gauge setting apparatus (2) comprises a setting bar (11) which is firmly held to the end of nipper shaft (6) through a fastening means (12). Because of this, while rotating the setting bar (11) the nipper shaft (6) also rotates wisely. A first self aligning member (13) is hinged on one side of the setting bar (11) but apart from the axis of fastening means (12) as shown in Fig-3. The first self aligning member (13) has internal thread for adopting the threads of the first screw means (14) of stud member (15). Said stud member (15) also provided with a second screw means (16) which is screwed into the threads of a hinged second self aligning member (17). The second self aligning member is hinged on slit bracket (9b). The first screw means (14) and first self aligning member (13) has threads with smaller pitch value for eg. 1.5mm. whereas the second screw means (16) and second self aligning member (17) has threads with comparatively larger pitch value for eg. 2mm. So that the differential pitch value of the first and second screw means (14, 16) is set to be constant, the movement is proportional to the pitch difference

During the nipper gauge setting, primarily the studs (10a, 10b) of the slit bracket assembly (9a, 9b) are loosened and hence the nipper shaft (6) becomes free to rotate. When the head (18) of the stud member (15) is rotated manually, depending upon the direction of rotation, the first and second screw means (14,16) are screwed or unscrewed with the first and second self aligning members (13,17) respectively. Since the first self aligning member (13) is hinged with setting bar (11), the setting bar ( 1) is getting a curvilinear movement towards or away from the second self aligning member (13) as shown by arrow. Because of it, the nipper shaft (6) also receives the angular displacement along with the setting bar (11) to obtain a required nipper gauge setting. A graduation scale (25) (as shown in Fig-5) is provided on the slit bracket (9b) and the pointer (26) provided on setting bar (11) helps to visually show the setting value.

For example, the first screw means (14) and first self aligning member (13) have threads with pitch value of 1.5mm, and the second screw means (16) and second self aligning member (17) have threads with pitch value of 2mm. If the head (18) is rotated one full revolution in clockwise direction, the stud (15) moves 2mm towards left direction with respect to the self aligning member (17). For the same revolution of screw (14) the relative movement of self aligning member (13) is to be 1.5mm. So the final relative movement between self aligning members (13) and (17) is 0.5mm.

Since the second self aligning member (17) is pivotably hinged in slit bracket assembly (9b), and the first self aligning member is hinged with nipper shaft setting bar(11), the resultant movement of the setting bar (11) with its associated nipper shaft (6) will be 2mm - 1.5mm = 0.5mm in clockwise direction. i.e., the angular displacement of nipper shaft (6) for one full revolution of stud member (15) will be,

2 - 1.5 = 0.5mm.

By this way, a very fine adjustment of nipper gauge is possible with the present invention. After adjusting to the required setting value, the screws (10a, nipper shaft (6) firmly from free of rotation. Both first and second self aligning members (13, 17) are rotatably hinged with setting bar (11) and slit bracket (9b) respectively so as to secure their position while nipper shaft (6) oscillates when machine is running. Thereby the nipper gauge setting is firmly maintained even though when the machine is in running condition.

Fig-4 of the drawings shows another embodiment of the present invention wherein a pair of screw means (19a, 19b) are located in the internal bores of "T" studs 20a, 20b. The end of the bores is slotted as in fig 4a. Also the end (22a) and (22b) of screws (20a) and (20b) are flattened. Hence the said screws (19a, 19b) can be linearly moved without rotation. Said "T" stud member (20a, 20b) which is integrated with setting bar (21) are formed with external threads with larger pitch value for e.g. 2mm. These pair of screw means (19a, 19b) is provided with threads with comparatively smaller pitch value for e.g. 1.5mm. So that the differential pitch value of the the "T" stud member (20a/20b) and the screw means (19a/19b)is set to be constant, the movement is proportional to the pitch difference. The flattened end (22a, 22b) of the pair of screw means (19a, 19b) are keep in contact with their corresponding stopper bushes (23a, 23b) which are firmly secured with slit bracket assembly (9b, 9a) respectively. Since the ends (22a, 22b) of the screw means (19a, 19b) are flattened with setting bar (21), said screw means (19a, 19b) are locked from rotating but free to slide inside the setting bar (21).

The another end of pair of screw means (19a, 19b) are provided with a pair of differential nut fasteners (24a, 24b) wherein the leg portion (A) comprises internal threads with larger pitch value for e.g. 2mm, and the head portion (B) comprises internal threads with smaller pitch value for e.g. 1.5mm as shown in Fig-4a. Hence the threaded leg portion (A) of differential nut fasteners (24a or 24b) engages with the threads of "T" stud members (20a or 20b), whereas the head portion (B) engages with the threads of pair of screw means (19a or 19b). During the nipper gauge setting, primarily the screws (10a, 10b) of the slit bracket assembly (9a, 9b) are loosened and the nipper shaft (6) becomes free to rotate. For example, when one of the differential nut fasteners (24a) is rotated in one direction and another differential nut fastener (24b) is to be rotated in opposite direction. Depending upon the direction of rotation, the screw means (19a) and the "T" stud member (20a) is screwed or unscrewed with the differential nut fastener (24a). If the differential nut fastener (24a) is rotated clockwise direction, the screw means (19a) is screwed into and pushes the stopper bush (23a) of slit bracket (9b). Meanwhile the setting bar (21) is getting a curvilinear movement away with respect to the stopper bush (23a). Since the setting bar (21) is rigidly connected to the nipper shaft (6) through a fastening means (12), the nipper shaft (6) also receives the angular displacement along with the setting bar (21) to obtain a required nipper gauge setting. Fig-5 of the drawings shows the top view of the present embodiment of the invention wherein a graduation scale (25) is provided on the slit bracket (9b) and the pointer (26) provided on setting bar (21) in order to view the setting values. The sarne kind of adjustment is possible when differential nut fastener (24b) is rotated in opposite direction. For achieving the precise setting value, the differential nut fastener (24a) may be rotated in one direction by countervail rotation of another differential nut fastener (24b) or vice-versa.

For example, the "T" stud member (20a) and the leg portion (A) (Ref Fig. 4a) of differential nut fastener (24a). have threads with pitch value cf 2mm, and the screw means (19a) and head portion (B) of differential nut fastener (24a) have threads with pitch value of 1.5mm. If the differential nut fastener (24a) is rotated one full revolution in clockwise direction, it will be screwed 2mm towards left direction onto the "T" stud member (20a) because of 2mm pitch. Meanwhile the same differential nut fastener (24a) is screwed 1.5mm towards left direction onto the screw means (19a) because of 1.5mm pitch. Since the differentia! nut fastener (24a) is screwed on bath "f'stud member

(20a) and the screw means (19 ) _; one revolution of nut fastener (24a) to be effected 1.5mm relative displacement between the fastener nut (24a) and the screw (19a). For the same revolution of nut fastener (24a) the relative displacement between nut fastener (24a) and "T" stud member is to be moved for its pitch 2mm. So the net relative movement between "T" stud and screw is 2 - 1.5

= 0.5mm. i.e., the angular displacement of nipper shaft (6) for one full revolution of differential nut fasteners (24a) will be,

2 - 1.5 = 0.5mm.

After adjusting to the required setting value, the screws (10a, 10b) of the slit bracket assembly (9a, 9b) are tightened in order to secure the nipper shaft (6) f irmly from free of rotation.

Since the present invention uses differential screw nipper gauge setting apparatus (2), it is possible to achieve more precised nipper gauge setting even 0.1mm accuracy. Moreover the construction is very simple and not uses any complicated instruments like vernier scale, so that a quicker setting is permissible. Furthermore, the operator need not be move from setting place to checking points frequently which enhance a user-friendly nipper gauge setting apparatus.

The embodiments shown herein are only exemplary. Further embodiments are possible within the scope of the invention.