Method of forming a ring doffer

A ring doffer is provided for carded web splitting that prevents loading of the card cylinder during operation by employing a circumferential groove therein to effect the web splitting that is cut in a reversing helix pattern at a pitch exceeding the width of the groove.

BACKGROUND OF THE INVENTION 
In arranging for increased carding operation output it is often desirable 
to produce a heavy web which is split after carding to provide multiple 
slivers of the weight required. Thus, if 50 grain slivers are required, a 
web of 100 grain weight is produced and split medially after carding to 
allow formation of two slivers of the required weight. 
The conventional means employed for such web splitting is a so-called ring 
doffer which is a card doffer roll having the clothing thereon disabled at 
a relatively narrow circumferential zone to effect the web splitting or 
division. The common practice heretofore followed in disabling the card 
clothing for this purpose has involved filling the clothing with a ring of 
metallic or plastic material at the circumferential zone where the 
splitting is to be done so that the doffer clothing will not strip at this 
zone and the doffer roll will accordingly strip separate webs at each side 
of this zone from the card cylinder for take-off and sliver formation. 
Such prior practice, however, has involved troublesome difficulty with 
loading of the card cylinder opposite the zone at which the doffer roll 
clothing has been disabled, and with the concerted efforts in recent years 
directed at increasing carding production rates such difficulty has been 
emphasized substantially. 
The present invention eliminates this difficulty in an exceptionally 
advantageous manner. 
SUMMARY OF THE INVENTION 
Briefly described, the ring doffer of the present invention is 
characterized in its preferable form by a clothing cover having a disabled 
zone formed by cutting at least one circumferential groove therein to the 
root of the clothing teeth and following a reversing helix pattern at a 
pitch (i.e., angle of inclination) exceeding the groove width, preferably 
in the order of three times that width. The number of grooves cut in the 
clothing cover will depend on the number of parts into which it is desired 
to split a carded web being handled. Usually the need will be for 
splitting the web medially into parts, and for this purpose the groove is 
located symmetrically in relation to the axial midpoint of the doffer. 
If desired, the cut groove or grooves can be filled with a metallic or 
plastic material comparable to the previously noted prior practice, or 
such a material can be filled in at a reversing helical zone defined 
between temporary taping applied at the clothing cover surface, or a soft 
plastic material or the like penetrable by the clothing elements can be 
taped into place in the reversing helix pattern to form the disabled zone, 
although no such aproximation of the indicated prior practice has been 
found necessary. 
Helical arrangement of the web splitting groove in the foregoing manner has 
the effect of maintaining the card cylinder clear of loading substantially 
as if the doffer clothing were continuous, which at the same time allowing 
sliver of excellent evenness and quality to be produced from the split web 
portions. The preferable ring doffer arrangement, as well as the method 
and means by which it is formed, are described further below in connection 
with the accompanying drawings.

DETAILED DESCRIPTION OF THE INVENTION 
In the drawing, a doffer roll is indicated by the reference numeral 10 
rotatably supported at journal portions of an axial shaft 12 in pillow 
block bearings or the like 14 on a frame structure 16. The frame structure 
16 may be one specially provided for use in forming ring doffers according 
to the present invention, or it may be a conventional card frame having 
the doffer roll 10 in place thereon, in which case the doffer drive, as 
well as the front girt and calendar rolls and other related operating 
structure thereat is removed to allow temporary installation of the means 
employed for cutting a web splitting groove in the doffer roll 10 as 
indicated at 18. 
In either case, with the doffer roll 10 securely supported but free for 
rotation, a sub-frame mount comprising a cross bar 20 fitted with two 
attaching legs 22 is fixed in place across the front end of frame 
structure 16 (i.e., at the bottom as seen in the drawing) to carry a drive 
motor 24 for rotating the doffer roll and a grinding unit 26 including a 
drive motor 28 from which a belt connection or the like at 30 reaches to a 
spindle on which a grinding wheel is carried at 32. The doffer roll motor 
24 is preferably a 60 RPM, 110 V, gear head type, and one end of the 
doffer roll shaft 12 is temporarily fitted with a sprocket 34 from which a 
chain connection 36 is extended to motor 24 as shown. 
The grinding unit 26 is slidably carried on the subframe cross bar 20 and 
has a pivotally connected linking rod 38 extending therefrom to one end of 
a follower arm 40 that is supported intermediate its length on a fulcrum 
arm 42 extending from the adjacent sub-frame attaching leg 22. At its 
other end, the follower arm 40 carries a cam follower roll 44 for riding 
the opposing face of a cam wheel 46 temporarily installed at the other end 
of doffer roll shaft 12, and a tension spring 48 is adjustably anchored on 
sub-frame cross bar 20 and fixed to grinding unit 26 so as to provide a 
basis by which follower roll 44 is maintained in riding contact with cam 
wheel 46. Grinding unit 26 is additionally provided with a handwheel 50 
operating a feed means (not shown) by which cutting depth of grinding 
wheel 32 is controlled. 
The foregoing arrangement is employed for cutting a web splitting groove 18 
in doffer roll 10 by first removing the tension from bias spring 48 an 
sliding the grinding unit 26 on sub-frame cross bar 20 to position 
grinding wheel 32 at the mid-point of the helical pattern in which groove 
18 is to be cut. Thus, if only a medially located groove 18 is to be 
provided as illustrated, the grinding wheel 32 is set at the axial 
midpoint of doffer roll 10. Then the installed cam wheel 46 is set at a 
centerline position, with which it should be marked, in contact with cam 
follower roll 44, after which cam wheel 46 is fixed on doffer roll shaft 
12 at this setting and biasing tension is restored at spring 48. A check 
should be made at this stage to be sure that the restored bias of spring 
48 has not disturbed the proper location of grinding wheel 32 in relation 
to doffer roll 10, and an appropriate resetting effected if it has. 
When the foregoing set-up has been checked out satisfactorily, the doffer 
roll and grinding unit drive motors 24 and 28 are both started to commence 
the groove cutting operation. For either 27" or 12" doffer rolls 10 a 6" 
grinding wheel 32 is suitable at a 1/4" width. A wheel of the 
"saw-gumming" type provides good groove cutting action, although any other 
reasonably comparable abrasive wheel might be used as well. A 1/3 HP, 1725 
RPM, 110 V drive motor 28 is advantageously provided. The clothing cover 
on doffer roll 10, which is normally formed of metallic wire according to 
current practice, is cut to the root of the clothing teeth by feeding the 
grinding wheel 32 to this depth from handwheel 50, and as the cam wheel 
and follower system provided will result in reciprocating the grinding 
unit 26 as doffer roll 10 is rotated the groove cutting will follow the 
reversing helical pattern illustrated. When a 1/4" grinding wheel is used 
to cut a groove 18 of essentially the same width it has been found that a 
helical groove pattern of 3/4" pitch provides excellent protection against 
cylinder loading in accordance with the present invention while producing 
split web portions of usual evenness and quality. 
The present invention has been described in detail above for purposes of 
illustration only and is not intended to be limited by this description or 
otherwise to exclude any variation or equivalent form or procedure that 
would be apparent from, or reasonably suggested by, the foregoing 
disclosure to the skill of the art.