Background Art In textile processing, a fibre plucking machine is used to pluck fibres from a stock of bales that are arranged on both sides of the machine. The conventional plucking machine comprises a trolley and a turntable mounted thereon. A plucking head assembly is attached to the turntable through a tower which is mounted on the turntable. The plucking head assembly consists of one or more plucking rollers, a suction arrangement and a grill arrangement. A locking spindle is housed inside the tower on which the plucking head assembly slide in a vertical direction.

The plucking rollers have a plurality of plucking teeth disposed on the outer surface thereof to pick up the fibres when the plucking head travels on and above the stock of the fibre bales. In the convention plucking machines, the plucking teeth forms an integral part of the

roller and are fixed permanently therein by welding or such other means. This arrangement is found disadvantageous as failure of a single tooth in the assembly necessitates replacement of the entire roller assembly. In order to avoid this disadvantage, rollers with multiple segments were constructed where each rollers is divided into different segments and each segment is provided with fixed teeth thereon. These segments constitute the entire roller assembly. This avoids replacement of the entire roller in case of damage or failure of a single tooth as replacement of the damaged segment alone is sufficient. Replacement of segments is also expensive and the down time of the machinery during such replacement is considerably high resulting in production loss. Disassembly of the damaged roller involves removal of contact rollers and grills which are heavy components leading to high labour.

In a conventional bale plucking machine, the grill is disposed beneath the plucking rollers wherein the width of the grill spacing has direct impact on the inlet of fibre and tuft formation. Therefore, the higher inflow of fibre lead to high tuft formation and lower inflow of fibre improves fibre quality. This is a factor for fibre

processing industry to desirably select between high production with a compromise on tuft formation and to select reduced production for achieving high quality of fibre. Known methods are available for increasing the inflow of fibre material by either lowering or lifting the plucking rollers or by swivelling the plucking rollers desirably. These methods involve complicated mechanisms and driving elements for enabling such movement or swivel of the plucking rollers. Conventional suction arrangement of the plucking head assembly consists of suction means, suction hood and collection system. Suction hood in the hitherto known suction arrangement is permanently bonded to the plucking head assembly. Such permanent bonding is found disadvantageous as it prevents easy access for cleaning and maintenance of the components housed within the head assembly. Contact rollers and the grill are to be dismantled to provide access for cleaning and maintenance of the conventional plucking machine.

The plucking head assembly is lifted and lowered by a drive system in which a drive medium such as a chain is connected to the head assembly. The other end of the chain is provided with counter weights for safety reasons.

During operation, the drive rotates, thereby enabling the

travel of the chain which in turn lifts and lowers the head assembly. The drive system of this known arrangement is housed in the tower of the plucking machine, and occupies considerable space therein. The existing system also requires expensive and complicated junction boxes for the control of the drive. Moreover, chain drives require frequent maintenance and cleaning and are prone to slip.

Slippage of the chain results in lowering of the head when not required thereby causing damage to the machinery. The conventional drive system is also prone to unexpected failures.

The turntable arrangement which is widely used in conventional plucking machines for turning the head assembly from one side of the machine to the opposite side includes complicated gear drive systems. These gears frequently get affected by fibre flies and fibre as they get stuck to grease present in the gears. Further, the gears require high momentum for rotation and are not easily accessible. In addition the known gear drive system is expensive and requires frequent maintenance.

In a conventional plucking machine, the plucking head assembly is enabled to travel horizontally on a

semicircular path in order to turn from one side of the machine to the other side of the machine for plucking fibre bales. In order to lock the plucking head assembly to ensure linear horizontal movement at one side of the machine and to avoid unexpected rolling back to the other side of the machine, one end of the spindle is inserted into a locking hole provided on the side of the trolley.

The plucking head gets locked when the spindle is inserted into the locking hole in the trolley. Once the plucking head completes plucking of fibres from one side of the machine, the spindle is lifted from the locking hole, and the turntable, which is now free to rotate, is rotated together with the spindle and the head assembly to the other side of the machine till the free end of the spindle is inserted into the locking hole on the opposite side of the trolley. In the conventional plucking machines, the insertion and the removal of the spindle in the locking holes are enabled by a separate spindle drive arrangement comprising of expensive and complicated driving means such as a motor which involves cost and frequent maintenance.

Disclosure of the Invention The object of the present invention is to provide a bale plucking machine which overcomes one or more of the abovementioned drawbacks or disadvantages.

Accordingly the present invention provides a bale plucking machine for plucking fibres from the bales arranged on both sides of the machine, comprising a trolley mounted on rails and having a locking hole on diagonaly oppsite sides; a turntable with a indexing hole rotatably mounted on the trolley; a tower mounted on the turntable; a plucking head assembly connected to the turntable through the tower and positioned by a spring biased locking spindle housed inside the tower, the said plucking head assembly having at least one feed roller, at least one plucking roller, a detachable suction hood and an interchangeable grill assembly, the said plucking roller having at least one detachable strip with a row of teeth attached to its outer periphery; a drive arrangement for rotating the turntable in a semicircular path so as to turn the plucking head assembly from one side of the machine to its opposite side, the said drive arrangement having a driving means for turning the turntable through a

driving medium and a guiding roller for guiding the driving medium to overlap more than half the circumference of the turntable; lifting and lowering means for lifting and lowering the head assembly, the said lifting and lowering means being housed in the plucking head assembly and comprising a shaft, at least one pair of rollers mounted on the shaft, a driving means for driving the shaft, and at least one pair of slings one end of which is fixed to the tower and the other end is attached to the said rollers.

The plucking head assembly of the bale plucking machine of the present invention includes plucking rollers provided with detachable strips of plurality of teeth on its periphery. Strips with damaged teeth may easily be detached from the roller and can be replaced with a suitable strip in good condition with minimum downtime.

Removal of the entire roller or a roller segment is thereby avoided. The strips may be of any desired length such that more than one strip may be fixed to form a single row of teeth. Strips may be fastened to the roller with the help of threaded insertion.

The interchangeable grill assembly of the plucking haed assembly consists of two longitudinal frame members

between which a plurality of grill bars are provided. The grill bars are shaped so as to allow two plucking rollers to rotate in the opposite direction with respect to each other. Bars are shaped such that the plurality of teeth provided on the plucking rollers do not interface with each other. The grill assembly consists of guiding means like shackles preferably made of stainless steel to guide the fibre material in the grill bars. The spacing of grill bars in one grill may be different from the spacing in another grill. For instance, spacing between bars in one grill assembly may be 60mm while in another assembly, the spacing may be 120mm. These grill assemblies may be fixed to the plucking head with the help of fasteners.

Depending upon the quality of fibre to be produced and the desired production rate, these grill assemblies may be interchanged easily. For instance when a grill with larger pitch spacing is mounted, the production rate is high and when a grill with a smaller pitch space is used the inflow of fibre is relatively low, thus reducing the production rate. Interchanging of one grill assembly with another is effected manually. Further, the suction hood of the plucking head assembly is made detachable providing easy access to areas located on or above the plucking

rollers and inside the plucking head assembly once the suction hood is detached from the head assembly. Thus the improved plucking head assembly of the bale plucking machine according to the invention minimises labour and downtime of the machine thereby optimising the production.

The improved arrangement for lifting and lowering the plucking head assembly comprises a driving medium and a drive system. The driving medium consists of a pair of slings. The drive system consists of a pair of rollers, a shaft connecting the rollers, and a motor. The drive system is housed inside the plucking head assembly. One end of each of the slings are fixed to the tower and the other end is fixed to the head assembly through the rollers of the drive system. The rollers are connected by the shaft which is driven by the motor. When the motor is driven the slings gets wound or unwound on said rollers thereby lifting or lowering the head assembly as desired.

The drive system for rotating the turntable includes a driving means, driving medium and a guiding roller. The driving medium transfers the drive force from the driving means to the turntable. The guiding roller guides the driving medium to overlap more than half the circumference of the turntable so that the turntable is

rotated in a semi-circular path on both, clockwise and anti-clockwise directions with lesser amount of force.

The driving medium keeps the dust away and thereby reduces maintenance and also less downtime in case of replacement.

The spring bias provided in the spindle enables the insertion of the spindle into the locking hole in the trolly so as to lock the plucking head assembly to a particular side of the machine.

Brief Description of the Drainas The features and advantages of the invention will be apparent from the following description which is given solely by way of example with reference to the accompanying drawings, in which; Fig. 1 shows a bale plucking machine of the present invention.

Fig. 2 shows a bale plucking machine of the present invention in a disassembled condition.

Fig. 3 shows a plucking roller of a plucking head assembly of the bale plucking machine.

Fig. 4 shows an interchangeable grill assembly of the bale plucking machine.

Fig. 5 shows a detachable suction hood and the plucking head assembly of the bale plucking machine.

Fig. 6 shows a drive arrangement for lifting and lowering the plucking head assembly of the bale plucking machine.

Fig. 7 shows a drive system for rotating a turntable of the bale plucking machine.

Fig. 8 & 9 shows locking arrangement for locking the plucking head assembly of the bale plucking machine.

Best mode for carrvina out the invention The bale plucking machine shown in figures 1 and 2 comprises a trolley (1) mounted on rails (2). A turntable (3) is rotatably mounted on the trolley. A tower (5) is fixed to the turntable (3) by means of a cam roll bearing arrangement. A plucking head assembly (6) is attached to the turntable through the tower (5) in such a way that the head assembly is capable of sliding in a vertical direction on a spindle housed inside the tower (5). The plucking head assembly (6) includes a detachable suction hood (7), a plurality of feed rollers (8), an interchangable grill (9) and a plurality of plucking rollers (10). The fibres plucked by the plucking head are fed to a suction duct (31) through a flexible hose (30).

The suction duct is covered by a belt (32). The plucking head assembly is lifted and lowered in vertical direction

with the help of a pair of slings (11,11') attached to a tower (5) at one end and to the head at the other end.

The control panel and an cperator panel are indicated by reference numerals 33 and 34 respectively.

In figure 3, reference numeral 10 indicate the plucking roller. A plurality of plates (16) are fixed permanently on the peripheral surface of the plucking roller. A strip (17) having a set of tooth arrangement (18) is fixed on each of the plates with fastening means.

The plucking roller is provided with a polygon shaped configuration on its circumferance.

The grill assembly shown in Fig. 4 consists of a frame member (41) made of steel in between which spacedly shaped grill bars (42) are welded with a spacing'd'. The shape of the grill bars allow the two rollers to work opposite to each other and the population of the teeth do not head towards each other. Guiding means (43), such as shackles, made of stainless steel is provided to guide the material properly into the grill bars (42).

Fig. 5 illustrates the plucking head assembly (6) and the detached suction hood (7). The plucking head has an opening (51) on which the suction hood is detachably

mounted. The suction hood includes a curved outer member (52), a side plate (53) laterally extending on either side thereof and a frame member (54) which enables the positioning of the suction hood within the opening in the head assembly. The suction hood is detachably mounted to the head assembly by means of fastening means (55,55').

The shape of the suction hood is a major factor which enables free and smooth flow of materials. To obtain best results, the maximum height of the suction hood should be between 2 to 3 times, preferably 2.67 times, of the diameter of the plucking roller.

In figure 6, reference numeral 5 indicates the tower of the fibre plucking machine, plurality of slings (11,11') are fixedly mounted on the tower with the help of fixing means (12). Fixing means may be clamps or rivets. Plurality of rollers 15 are mounted on the head assembly through a shaft (14), the other end of each of the sling is rotatably wound on these rollers. The shaft is driven by driving means such as motor (13). When driven by the motor, the sling gets wound or unwound on the rollers thereby varying its length. This determines the vertical positioning of the head assembly.

The drive system for rotating the turntable (3) shown in figure 7 comprises a driving means such as electric motor (19). The motor drives a toothed pinion (20) which is connected to the turntable (3) through a driving medium such as toothed belt (21). The toothed belt is guided through a guiding roller (22) so as to overlap more than half the circumference of the turntable. This overlapping enables the turntable to rotate both in clockwise and anti-clockwise directions with a lesser amount of force. Preferably, 3/4th circumference of the turntable is overlapped by the toothed belt (21). The electric motor (19) and the toothed pinion (20) may be separated by a cover (23).

As shown in figures 8 and 9, the turntable (3) is mounted on top of the trolley (1) and is capable of rotating on a semicircular path so as to move a plucking head assembly (6) from one side of the machine to the other side. The plucking head assembly (6) comes into contact with the spindle (4) with the use of a lifting guide (25) in such a way that the head travels vertically on a linear path. The spindle is provided with a spring bias (24) and a collar (26) on its top end and guides at both ends. The bottom end of the spindle passes through a

positioning hole (29) in the tower, an indexing hole (28) in the turntable and one of the locking holes (27) in the trolley when the plucking head is locked for plucking fibres from the fibre bales arranged on any side of the machine.

Initially, the plucking head (6) plucks fibres from the bales arranged on one side of the fibre plucking machine. The plucking head travels in forward and backward directions along with the trolley (1). The free end of the spindle (4) is inserted into the locking hole (27) in the trolley, as shown in fig. 9, so that the plucking head is locked to one side of the machine and is not turned to the other side of the machine. Once the fibre bales arranged on one side of the machine are plucked completely/partialy, the plucking head (6) is lifted upwards and the lifting guide (25) lifts the spindle (4) so that the free end of the spindle is released from the locking hole (27) in the trolley (1) as shown in fig. 8.

The plucking head (6) is now free to turn to the other side of the machine. The turntable (3) enables the plucking head (6) to travel in a semicircular path. The

spindle (e) alsc travels along with the head (6) abutting th& trolley (1) till the free end of the spindle gets inserted into the locking hole (27) on the opposite side of the trolley (1). The plucking head travels downwardly once the turntable (3) turns to the other side of the machine and sensed by the controls. Once, the free end of the spindle (4) is inserted into the locking hole (27) of the trolley (1) the plucking head travels horizontally in a linear path to pluck fibres from the bales that are arranged on the other side of the machine. This process continues so that the plucking head (6) of the fibre plucking machine can pluck fibres continuously from the fibre bales arranged on both sides of the machine.

Industrial Applicability As explained hereinbefore, a bale plucking machine according te the present invention enables plucking of fibres from a row of bales arranged on both sides of the machine in order to obtain blends with predetermined weight and proportion in a most efficient and ecconomical manner.