Title of Invention


Abstract This invention relates to automatic doffing equipment. It consists of a doffer beam provided with a plurality of grippers. Each gripper has an upper and lower retaining elements pivtoably and rotatably mountable at the doffer bar. Grippers are provided with gripping means which are actuated either with compressed air or with electricity. Downtime of the spinning machine is minimised as malfunctioning of the system does not necessitates stopping of the process. The grippers do not fully get separated from the doffer beam as either the top or the bottom retaining element remains attached to the doffer beam. As the grippers do not fall away from the beam considerable damage is avoided. Sensing means and LED's are also provided to indicate the malfunctioning areas. PRICE: THIRTY RUPEES
Full Text This invention relates to automatic doffing equipment for ring spinning machine for changing a plurality of full tubes or cops.
in textile spinning processes full tubes or cops are sinniltaneously or jointly lifted and moved away from spindles and are replaced by empty tubes.in the past, doffing was carried out manually.Eventually mechanisation and automation replaced manual doffing system.Though several automatic doffing equipments are available to the textile industry, human supervision and monitoring of the operation are still found necessary.
in known automatic tube changing devices, the gripper gets separated from the doffer beam completely in the event of any malfunctioning and holds on to the tube which is either full or empty.One of the major disadvantages of this device is that the released gripper falling on full cops damage the yarn thereby making post-spinning process difficult. it is also necessary to locate the released grippers and reposition the same before restarting the machine, resulting in increased down time and consequential loss of production.

in the event of malfunctioning, the released grlpper may fall away from the tube causing yarn breakage at adjascent spindles.The falling gripper may get entangled between rotating compo¬nents causing damage to the component as well as to the gripper itself, Prolonged downing of the machinery to remedy or rectify the damages caused by a falling gripper affects production adversely.
The object of this invention is to develop an automatic doffing equipment avoiding the aforesaid drawbacks. The equipment developed by us is of modular construction, and is fully auto¬matic.Spinning starts automatically without manual inter¬vention even if there is a malfunctioning during the doffing cycle, Down-time of the machine is therefore minimised, there¬by increasing the rate of production.The doffing cycle with this system is reliable, durable and servicable.
The doffing equipment consists of a doffer beam, A plurality of grippers are mounted throughout the length of the doffer beam.The grippers are attached to the doffer beam with the help of flexible retaining elements.Sensing means are also provided for generating electric signals in response to the release of any one of the flexible retaining elements from the doffer beam due to malfunctioning The grippers are provided with gripping means like inflatable elastic diaphragm or with a mechanical linkage.The doffing equipment has actuating means such as a compressor for regulated air supply to the diaphragmor a piston

actuated by a solenoid to close or open the mechanical linkage of the grlpper.The flexible retaining elements hold the gripper to the doffer bean plvotably.
in one embodiment of the invention,the actuating means for the doffing equipment consists of an air duct running through the length of the doffer bar.The air duct is connected to the elastic diaphragm by meansof an aperture which is sealed with sealing elements.Optionally, one non return value is positioned on the doffer beam at the inlet of the air duct to each of the grippers.This cuts the air supply to the elastic dlaphragm when the gripper moves away from the doffer beam due to disturbing forces or malfunctioning.This avoids any pressure drop in the air duct in the doffer beam and saves costly compressed air that flows through the duct.
in another embodiment, the actuating means is a piston operable by a solenoid provided at each of the gripper unit.The piston operates the mechanical linkage of the gripper unit for grip¬ping or ungripping tubes.
The automatic doffing equipment for ring spinning machine according to this invention comprises a doffer beam having a plurality of grippers plvotably and rotatably mounted thereon, each gripper having releasable top and bottom retaining elements and gripping means for gripping the tubes, actuating means for releasing either the top or bottom retaining element of the grip¬per from the doffer beam, and sensing means for sensing the

release of the said retaining element from the doffer beam.
The doffer beam may have a plurality of lateral protrusions or lugs for engaging the retaining elements of the grippers. in one embodiment actuation of the gripper is with the help of compressed air which runs through the length of the doffer beam and is in comraunicatlon with each gripper unit through an aperture.A non return valve may also be positioned at the aperture.
When the tube on the spindle is jammed due to any malfunctioning during spinning process, a downward force is exerted on the grip¬per, which rotates at the pivoting point to move the top retain¬ing element and the gripper away from the doffer beam at that point.This deflates the elastic diaphragm, connected to the gripper as the air supply thereto is reduced.it should be understood that the gripper does not get fully detached from the doffer beam as no upward force acts at the bottom retaining element which is held in its position.The gripper therefore is inclined only to a small angle which does not interrupt the spinning process while the doffing beam moves down to pick up empty tubes.Since the air supply to a particular gripper is cut or reduced, and as the gripper does not get fully detached from the doffing beam, auto crushing of empty tubes by the grip¬per is avoided.Release of a retaining element of the gripper is sensed by the sensing means which generates an electrical signal to indicate the location of individual disturbances.On receiving such a signal from the sensing means, perferably through LED, the location is identified and the defect or mal¬function can be rectified, without stopping the spinning process.

he released retaining element of the gripper may then be manually replaced.
Another malfunctioning that occurs frequently is that one or more empty tubes in the transport belt may take an inclined position instead of the normal perpendicular position.An upward force is then exerted on the gripper which rotates about the top retaining element* The gripper moves away from the doffer beam at bottom retaining element before air is supplied thereto, the gripper being held by the top retaining element at the doffer beam.
The doffing cycle continues with zero down time.Signal received from the sensing means enables the operator to rectify the defect and reposition the retaining means thereafter.The downtime of the machine is zero and auto crushing of the empty spindle is avoided due to the inclined position of the gripper.
Auto crushing also occurs when the doffer comes to load an empty tube while the spindle has a full cop.This situation arises when the pressure in the main line is dropped and the holding force of the gripper is insufficient to lift the full tubes which requires maximum retaining force.The pressure may be sufficient to lift the empty tube which results in auto crushing.The swinging in of the doffer beam a few millimeters above the spindle helps the full tube on the spindle to deflect the empty tube away.The doffer beam then moves downwards thereby cutting off air supply to the gripper.The deflected tube falls

away from the spindle and the machine whereas the remiining empty tubes sit on the spindle.The operator then has to manually replace a full tube with an empty tube.The doffing cycle and the spinning process continue uninterrupted even during this malfunctioning and the downtime of the machine is zero.
it is preferred to have two sensing means located at the top and bottom retaining elements of the grlpper as it helps to locate specific malfunctioning points depending on the direction of the forces that act on the grippers.Apart from individual sensing means and LED for each grlpper and retaining means, a coiimon lamp may be provided to indicate the section where dis¬turbance or malfunctioning has occured.
After the completion of the doffing cycle, the automatic start of the spinning can be stopped, if required, automatically by setting a value for the maximum number of grippers (3) mal¬functioned during the doffing cycle.Once the grippers are set in position, the cycle can be resumed,
A safety switch with a cord running through out the length of the doffer beam is provided for stopping the spinning machine in case of any emergency.
in another entoodiment of this invention, the actuating means for releasing the retainer in the gripper is effected with the help of a solenoid activated piston operable by electricity.This avoids usage of compressed air as the actuating means disclosed in the first embodiment.The gripper is provided with a solenoid

actuated piston and a mechanical linkage for gripping and ungrlp-ping of the tubes.The gripper is held in position with the help of coil spring which forces the piston to get hold of the tube.in the unactuated state the mechanical linkage is in the open condition but when actuated by the solenoid,the piston moves to the outermost position to close the mechanical linkage.
As described earlier when the full cops are held tightly to the spindle or is Jammed, the gripper is subjected to a downward force which moves it away from the doffer beam.Once the grip¬per moves away, the power supply to the solenoid is cut, the piston moves back and the linkage opens up releasing the full cop from its grip.The doffing cycle continues and the open linkage avoids picking up of empty tubes thus preventing auto crushing.Sensing means sends an electric signal regarding re¬lease of the gripper from the doffer beam.The released gripper may on receipt of signal be positioned back manually.Similarly when a vertical upward force is exerted due to malfxmctioning, the gripper moves away from the doffer beam as already explained.
it is also within the scope of this invention to provide two solenoids and two pistons mounted on a beam.Normally the two solenoids are in an unactuated state which keeps the pistons intact and the gripper is held close by the coil spring.When the gripper is released and is about to enter a tube for holding or replacing the same, an electrical signal is supplied to the solenoid which moves the pistons apart.Once the gripper has

entered the tube, the solenoids get deactivated and the coll spring forces the pistons to hold the tube at its circumference.
This invention will now be described with reference to the figures in the accompanying drawings.
Figure i shows the sectional view of the doffing equipment wherein reference numeral (1) shows the doffer beam, numeral (5) indicates the air duct that runs through it.Lugs or protrusions are indicated by numerals (2) and (2a), Reference
number (3) indicates gripper which may be made of light weight materials.Flexible retaining elements are shown by numerals (4) and (4a), The actuating fluid is air and is supplied to an elastic diaphra^rr shown by numeral (7), Apperture (6) connected the air duct 5 to the dlaphragm.Sealing element (8) seals the doffer beam (1) and the gripper.Sensing means consisting of sensors (11) and (i1a) and sensing elements (12) and (12a) are located on either side of the doffer equipment, Non return valve is indicated by reference number 9,
Figures ii and iii show alternate embodlments of this invention
wherein the actuating means is electrical.in figure 2, numeral 1 indicates the doffer beam and numeral 3 shows the gripper which is held to the doffer beam in a manner shown in Figure i and not illustrated in Figures ii and iii.The actuating means consists of a solenoid (2), a piston (5) and a mechanical linkage (4).Tube for gripping is shown by numeral (7), while

6 shows the coil spring.
Another embodiment of gripping means is depicted in Figure iii where numeral (1) stands for the doffer beam.The gripping means has (2) and (2 a ) mounted on the doffer beam and is held in a closed position by coil springs 6, Two solenoids 3 and 3(a) and two oppositely disposed pistons 4 and (4a) also provided.Normally the two solenoids are in the unactuated state and hence the two pistons remain intact and the grlpper is held in a closed position by the coil spring.During malfunctioning the gripper is moved away from the doffer beam, the solenoids get actuated and the pistons sre moved apart.Once the gripper enters the tube, the solenoids get deactivated and the pistons hold the tube with the help of coil springs-Various other modifications known to persons skilled in the art are also within the scope and ambit of this invention and the appended claims.

1, An automat1c doff1ng equ1pment for r1ng sp1nn1ng mach1ne compr1s1ng a doffer beam (1) hav1ng a plural1ty of gr1ppers (3) plvotably and rotatably mounted thereon, each grlpper hav1ng releasable top (4) and bottom (4a) reta1n1ng elements and gr1pp1ng means (7) for gr1pp1ng the tubes, actuat1ng means (5,6) for releas1ng e1ther the top or the bottom reta1n1ng elements of the grlpper from the doffer beam and sens1ng means (11, 11a) for sens1ng the release of the reta1n1ng elements from the doffer beam,
2, The doff1ng equ1pment as cla1med 1n cla1m 1 where1n each grlpper 1s mounted on the doffer beam on lugs (2 and 2a) and 1s sealed thereto w1th seal1ng leaves (8).
3, The doff1ng equ1pment as cla1med 1n cla1ms 1 and 2 where1n actuat1ng means 1s a duct (5) runn1ng through the lengt1v of the doffer beam and commun1cat1ng w1th each grlpper through
an aperture (6) for passage of compressed a1r therethrough and the gr1pp1ng means 1s an elast1c d1aphragm,
4, The doff1ng equ1pment as cla1med 1n cla1ms 1 to 3 where1n
a non return valve 1s prov1ded at the a1r 1nlet of the grlpper,
5, The doff1ng equ1pment as cla1med 1n cla1m 1 where1n the
actuat1ng means 1s a p1ston energ1sable by a soleno1d, the
gr1pp1ng means cons1st1ng of a mechan1cal l1nkage held together
by a co1l spr1ng, the movement of the p1ston clos1ng and open1ng
the mechan1cal l1nkage.

6. The doff1ng equ1pment as cla1med 1n cla1m 1, where1n the gr1pp1ng means
compr1ses two oppos1tely d1sposed p1stons, co1l spr1ng connected thereto and
two soleno1ds for energ1s1ng the sa1d p1stons.
7. The doff1ng equ1pment as cla1med 1n any one of the preced1ng cla1ms, where1n
sens1ng means compr1ses a sensor wh1ch generates a s1gnal that act1vates a
8. The doff1ng equ1pment as cla1med 1n cla1ms 1 and 7, where1n each gr1pper 1s
prov1ded w1th a sensor and a LED.
9. The doff1ng equ1pment as cla1med 1n cla1ms 1, 7 and 8, where1n the sens1ng
means 1s connected to a common 1nd1cat1ng means such as a lamp.
10. The doff1ng equ1pment as cla1med 1n any one of the preced1ng cla1ms, where1n
a safety sw1tch and a cord runs through the doffer for stopping the operat1on
11. An automat1c doff1ng equ1pment for r1ng sp1nn1ng mach1ne substant1ally as here1n descr1bed w1th part1cular reference to the f1gures 1n the accompany1ng draw1ngs.


1397-mas-1996 abstract.pdf

1397-mas-1996 claims.pdf

1397-mas-1996 correspondence-others.pdf

1397-mas-1996 correspondence-po.pdf

1397-mas-1996 description (complete).pdf

1397-mas-1996 drawings.pdf

1397-mas-1996 form-1.pdf

1397-mas-1996 form-26.pdf

Patent Number 194550
Indian Patent Application Number 1397/MAS/1996
PG Journal Number 08/2007
Publication Date 23-Feb-2007
Grant Date 02-Jan-2006
Date of Filing 07-Aug-1996
# Inventor's Name Inventor's Address
PCT International Classification Number D01G15/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA