AN IMPROVED NIPPER FRAME FOR A COMBING MACHINE
FIELD OF THE INVENTION

[0001] The invention generally relates to the field of textile industry. More particularly, embodiments of the invention relates to a nipper frame in the lap nipping mechanism of the combing machine.

BACKGROUND

[0002] A comber of a textile fiber combing machine includes a combing cylinder, a top comb, a pair of detaching rollers and a nipper apparatus. The nipper apparatus rocks back and forth while nipping sheet-like fibers hereinafter referred to as "lap", supplied thereto. The combing cylinder has a series of needles embedded on its peripheral surface. As the nipper apparatus moves backward, the needles comb the forward end of the lap. This action is called "combing". This combing action removes short fibers from the lap, producing a thin sheet-like fiber product hereinafter referred to as "fleece".

[0003] Typically a nipper apparatus of the textile fiber lap comber includes a nipper frame, a bottom nipper fixed on the nipper frame at its front end, and a top nipper to nip the lap in cooperation with the bottom nipper. The top nipper nips the lap at the tip of the bottom nipper. The nipper frame is capable of executing a rocking motion between a backmost position, wherein the tip of the bottom nipper is proximate to the cylinder needles and a foremost position, wherein the tip is proximate to the detaching rollers.

[0004] Further, the nipper frame is driven by a nipper shaft located below the frame, and is supported in a rockable manner by a four bar link mechanism with the nipper shaft.

The nipper shaft is mounted on the machine frame and oscillated by a slider crank mechanism. The swinging motion of the nipper shaft is converted as rocking motion of the bottom nipper through the four bar link mechanism. The four bar link mechanism as mentioned above, includes a crank arm with its one end is pivotally connected with nipper shaft and other end is being connected with the back end of bottom nipper frame.

The front end of bottom nipper frame is connected with a rocker arm. The rocker arm is pivotally mounted on the circular comb shaft.

[0005] As the nipper frame rocks, the tip of the bottom nipper moves along an upward projecting arc, which is part of a circle encompassing the combing cylinder circle. In a total path along which the tip of the bottom nipper together with the nipper frame rocks, there exists a point where the bottom nipper tip nips a lap in cooperation with the top nipper and releases the lap. The section in which the tip of the bottom nipper approaches the cylinder circle results in combing.

When the tip of the bottom nipper reaches the foremost position in the rocking stroke, the tip is located below a position where a pair of upper and lower detaching rollers nip a succeeding fleece.

[0006] This arcual movement and the clearance between nip and combing surface decides the level of combing and the nipper movement decides the nipping speed. In the aforementioned combing technology, reducing the clearance than a certain extent (for example less than 0.25mm) would lead to hindrance of combing cylinder with bottom nipper. In addition, the rocking stroke of the nipper frame generates more vibration during high-speed machine operation. To reduce such vibration, the to and fro motion distance of nipper frame (nipper movement) has to be reduced. Reducing the nipper movement is also not possible in the existing combing technology which is disadvantageous.

[0007] There has thus been a persistent need to develop a nipper frame that would reduce the distance between bottom nipper nip and combing circle and increase nipping speed of the combing machine without compromising the output quality. The present invention would provide an improved combing machine that would overcome all disadvantages present in the existing combing machines.

SUMMARY OF THE INVENTION

[0008] The existing combing machines in which the nippers are driven by a standing pendulum four bar driving arrangement and creates an upwardly curved nipper path, the ratio of length between the crank arm and rocker arm is maintained as 1.11. The nipper movement is maintained to a distance of more than 30mm. Also a clearance of 0.2 to 0.5mm is achieved between nipping point and combing surface and said clearance is varied up to 0.3mm.

[0009] In accordance with the basic aspect of the present invention, the ratio of length between said crank arm and rocker arm of the nipper frame is preferably 1.15 to 1.40.

[0010] In accordance with the aspect of the present invention, ratio between length of crank arm and radius of combing cylinder is preferably 1.4 to 2.0.

[0011] In accordance with the still another aspect of the present nipping point and combing surface and a minimum variation of 0.1mm in the clearance is achieved.

[0012] The above mentioned nipper frame overcomes the disadvantages present in the conventional nipper frame and nipping mechanism and by this, improved combing arc and minimum clearance can be achieved.

OBJECT OF THE INVENTION

[0013] It is thus the basic object of the present invention to provide a nipper frame with improved crank and rocker arm which avoids aforementioned disadvantages of conventional nipping mechanism in the existing combing machines.

[0014] Another object of the present invention is to provide a textile combing machine with improved nipper frame that will minimize the clearance between combing surface and nipping point and improves the nipping speed compared to the existing combing machines.

[0015] Still another object of the present invention is to provide a textile combing machine with improved nipper frame that will minimize the moving distance of nipper frame and improves the nipping speed, output quality and productivity compared to the existing combing machines.

[0016] These and other objects, features and advantages of the present invention will become more apparent from the ensuing detailed description of the invention taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Example embodiments are illustrated by way of example and not limitation in the figures of the accompanying figures, in which like references indicate similar elements and in which:

[0018] Fig - 1 of the drawings illustrates the circular comb and nipping mechanism of the existing combing machines.

[0019] Fig - 2 illustrates the clearance between combing surface and nipping point as known in the existing machines.

[0020] Fig - 3 describes the crank and rocker arm arrangement of a four bar link mechanism according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0021] An embodiment of the present invention will be described with reference to the drawings.

[0022] Fig - 1 and Fig - 2 of the drawings illustrates the circular comb and nipping mechanism of the existing combing machines. The circular comb (1) consists a base cylinder (2) and a combing segment (3) which is being mounted on a shaft (4) and the shaft (4) is being driven by a driving means such as motor (not shown). A nipper mechanism is provided over circular comb (1). Said nipper mechanism consists a bottom nipper (5), top nipper (6) and feed roller (7). The bottom nipper (5) rocks to and fro and feed roller (7) feed the lap sheet and top nipper (6) open and close to clamp the lap sheet during combing. The nip portion (9) of top and bottom nipper hold the fibers firmly to facilitate combing action. The bottom nipper (5) is oscillated by means of an oscillating nipper shaft (10). Said nipper shaft (10) is mounted on the machine frame and oscillated by a slider crank mechanism. The nipper frame consists a driving means and is connected between circular comb shaft (4) and nipper shaft (10) to facilitate swing able movement of the nipper shaft (10). The swinging motion of the nipper shaft (10) converted as rocking motion of bottom nipper (5) through a four bar link mechanism. The fiber material combed by the combing segment (3) is collected by the pair of detaching rollers (14).

[0023] Fig - 2 illustrates the clearance between combing surface and nipping point as known in the existing machines. The lap is held by the edge portion of bottom nipper (5a) and top nipper (6a) and that tip is so called as "Nip". When the nipper moves from foremost position to backmost position, the nip (9) makes upward convex arc over the combing segment (3). During this operation, combing needles (16) which are provided in the combing segment (3) combs the lap hold by the nip. While the lap undergoes combing, the nipper end moves maintaining a certain clearance 'S' between the nip (9) and the combing segment (3). Combing and cleaning efficiency of the combing machines can be improved by minimizing the clearance distance 'S' as lesser as possible. The clearance distance in the known art is minimized up to 0.2 to 0.5 mm and lesser than that is not possible due to the limitations in the existing technology.

[0024] Fig - 3 describes the crank and rocker arm arrangement of a four bar link mechanism according to the present invention. Said four bar link mechanism consists a crank arm (11) and its bottom end is pivotally connected with nipper shaft (10) and top end is being connected to the back end of fork arm (12). The back end of bottom nipper (5) is connected with front end of fork arm (12) and front end of bottom nipper (5) is connected with a rocker arm (13). The rocker arm (13) is pivotally mounted on the circular comb shaft (4). This arrangement facilitates to rock the nipper back and forth and to create upward convex arc over the combing segment. According to the present invention, a minimum clearance and minimum nipper moving distance is achieved by altering the length of rocker arm (13) and crank arm (11). The ratio between the length of crank arm (11) and rocker arm (13) is maintained between 1.15 to 1.40 to achieve the desired results.

[0025] In accordance with the another aspect of the present invention, ratio between length of crank arm (11) and radius (R) of combing cylinder is preferably lies between 1.4 to 2.0.

[0026] In accordance with the still another aspect of the present invention, with the reduced nipper movement, a clearance of 0.2mm to 0.3mm is maintained between nipping point and combing surface and a minimum variation of 0.1mm in the clearance is achieved.

[0027] The invention allows the following advantages to be obtained. The moving distance of bottom nipper is minimized and by this collision between bottom nipper and combing cylinder is avoided. Advantageously, clearance between nip portion and combing segment is minimized and maintained uniform while combing. The nipping speed and feed weight of the comber can be increased. By maintaining desired clearance between nipper and combing segment, higher lap weight with desired quality level can be achieved. Advantageously, overall productivity can be improved.

[0028] The invention, as described herein and as illustrated by diagram provides an improved nipper for a textile fiber combing machine. The foregoing description of the invention has been set for merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to person skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.

We claim:

1. A nipper arrangement for a combing machine having a combing segment comprising a nipper, a nipper shaft for mounting the nipper and a combing shaft operationally coupled to the nipper arrangement characterized in that a link mechanism is coupled to both the nipper shaft and the combing shaft, wherein the ratio between the length of crank arm and rocker arm is in the range of 1.15 to 1.40.

2. The arrangement according to claim 1, wherein the link mechanism is a four bar link comprising:

a. a crank arm having a first end and a second end, wherein the first end is pivotally connected with the nipper shaft;

b. a fork arm coupled to the second end of the crank arm;

c. a bottom nipper connected to the free end of the fork arm; and

d. a rocker arm coupled to the bottom nipper.

3. The nipper arrangement according to claim 1, wherein the movement from the link mechanism is transferred to the bottom nipper for providing the to and fro motion.

4. The nipper arrangement according to claim 1, wherein the clearance between the combing surface and the nipping point is in the range of 0.2mm to 0.3mm.

5. The nipper arrangement according to claim 1, wherein the ratio between length of crank arm and radius of combing cylinder is 1.4 to 2.0.

6. The nipper arrangement as illustrated in the drawings and as described in the specification.

7. The nipper arrangement as illustrated in the drawings and as described in the specification.

8. A combing machine having a nipper arrangement as claimed in claims 1 to 6.