US2120108A - Apparatus for liberating useful fibers - Google Patents

Description

June 7, 1 938.

R. w, MCLEANI 2,120,108

APPARATUS FOR LIBERATING USEFUL FIBERS Filed May 11, 1935 Patented June 7, 1938 UNITED STATES,

PATENT OFFICE APPARATUS FOR LIBERATING USEFUL FIBERS chusetts Application May 11, 1935, Serial No. 20,952

11 Claims.

This invention relates to the liberation of useful fiber, or fibrous material, from its attachments, for example from seeds, by the use of toothed disks or saws projecting through slots in a grate-fall, and relates more particularly to an improved method of and apparatus for use in so liberating fibers from their attachments. As herein disclosed the invention is shown as embodied in a linter gin for delinting cottonseed, but I contemplate its wider utility in any mechanism of the general class.

In one common form of gin, the slots for the saws in the grate-fall are defined by independent grate-bars, adjacent bars being in substantial contact at their upper and lower ends where they are supported by transverse rails,the bars being recessed or relieved along their sides, intermediate their upper and lower ends, so that the opposed recesses in adjacent bars collectively form the slot in which the saw blade turns. Sometimes these slots are somewhat widened near their upper ends on the theory that such wider spaces or holes will permit foreign matter, such as trash, leaf stalks, pebbles or the like, which may be caught by the saw teeth, to escape.

However, as these holes are soon pluggedup during use, this theoretical utility is of little practical value but, on the other hand, it has been observed that when these openings are apparent1y plugged or even when the openings are omitted, there is a tendency for fiber to enter between the closely adjacent upper ends of the bars and to catch and cling so as to form masses in the space behind the grate-fall and above the doffing brush. This tendency of the fibers to form into streamers or tags of substantial size at this point may perhaps be, in part at least, due to electrification. When these streamers become of suflicient weight, they break off and drop down into the moting space and are moted out with the motes, so that this fiber is lost, and loss of fiber from this cause may amount to a substantial percentage of the total output of the gin. On the other hand, if these streamers, which usually include dirt and trash as well as clean fiber, are carried along with the other fibers to the condenser, the value of the product of the machine is greatly lessened.

Although the action which takes place adjacent to the ginning point is not easily observable, I have ascertained that even a microscopic crack, invisible to the eye, at the end of the slot (for example, such as results from fitting adjacent gratebars together), provides a place in which fibers, impelled at high velocity by the saw teeth,

take root,so to speak, thus providing an anchorage for the accumulation of an accretion of material.

Not only do minute cracks or irregularities at the end of the slot itself cause tagging, but abrupt shoulders, projections, crevices or rough surfaces upon or in the parts defining the space immediately above and behind the upper ends of the slots, or the sudden contraction of this space, also result in the accumulation of streamers of lint at this point.

As one step in the effort to eliminate the tagging effect, I believe it desirable to have the ends of the slots defined by transverse elements which are integrally continuous from one side to the other of the slot so that not even an invisible crevice or crack exists at this point.

In my patent just referred to I have suggested the desirability of guarding the joints between adjacent bars nearly down to the ginning point. However, it does not appear to be wholly sufficient merely to cover or guard the minute cracks or joints between the adjacent grate-bars beyond the ends of the slots, since further experiment has convinced me that for most effective results the distance between the slot-terminating element and the path described by the tips of the saw teeth is critically small, to wit, of the order of one-sixteenth of an inch. Wherever practicable, a spacing of less than one-sixteenth inch is recommended. With this small spacing the tips of the saw teeth pass so close to the slotterminating element as to sweep the end of the slot itself completely clean of lint, so that the incipient growth of tags or streamers is prevented, not only along the joint between adjacent bars above the slot proper, but within the end of the slot itself.

The requisite accuracy of setting of the saw cylinder shaft relatively to the grate-fall may readily be obtained by the use of mechanism such Fig. l is a fragmentary front View of the upper part of a one-piece grate-fall, showing the upper ends of the slots and with the saw blades projecting through the slots and arranged in accordance with the present invention;

Fig. 2 is a fragmentary vertical section of the blade, arranged in, accordance with the present 7 Fig. 4 is a section, to larger scale, substantially V on the line 44 of Fig. 3, showing that part of the grate-fall which is immediately above the ginning point, together with a portion of a saw invention; and I v Fig. is another view, similar to Fig. 1, but showing a slight further modification.

Figs. 1 and 2 illustrate a grate-fall 1 consisting of a single piece of sheet material, for example steel, suitably shaped at its upper and lower edges for anchorage to the transverse rails 2 and 3, respectively. As illustrated in Fig. 2, the rail 2 is integral with the rear wall of the roll box of the gin, and the sheet I is set into a recess in the rail so that the upper surface of the sheet is substantially flush with and forms an uninterrupted continuation of the inner curved surface 2 of said wall. The lower surface 2 of the rail 2' is smooth (preferably being buffed and polished), and is preferably upwardly and rearwardly inclined at'2 so as to provide a space which flares, or increases upwardly in vertical dimensions, rearwardly of the ginning point. With an arrangement substantially as just described, no ledges, recesses, projections or rough surfaces are opposed to the normal movement of the lint carrying air current, such as might provide mechanical lodgement for fiber, or such as would formpoints for accumulation of static electricity, while by reason of the rapid upward increase in the dimensions of the space rearwardly of i the ginning point, air currents are set up which effectively sweep the surfaces clean of lint. The slots 4 in this grate-fall are conveniently formed 'by a milling operation which provides slots of very accurate width and spacing. Preferably the terminal elements of these slots are concavely curved, as indicated at 5, so that the opposite side walls of the slotgradually approach the'plane of the tooth tips thereby to minimize the space at each side of the tip of the saw tooth. While noattempt has been made in the drawing to show the exact shape of the saw teeth, it is well known to those skilled in the art that gin saw teeth are of a more or less pyramidal shape, tapering in thickness toward their tips. Thus the narrowing of the slot at its terminus is highly desirable in order to minimize the clearance between the extreme tip portion'of the tooth Patent No. 1,988,850, above referred to. The saw blades 6 are mounted on the sawcylinder shaft 1, the shaft bearings and grate-fall preferably beingrelatively and accurately adjustable, for example by means such "as disclosed in McLean Patent No. 1,988,850, above referred to. The saw blades 6 project through the slots 4' and as the saws turn in the'direction of the arrow A (Fig. 2) the teeth of the saws carry the detached fiber downwardly and rearwardly through the slots in the grate-fall.

In accordance with the present invention the saw shaft is so set relatively to the grate-fallthat the circumferential path, indicated at 8 (Fig. 1), in which the tips of the sawteeth move, is within approximately one-sixteenth of an inch or less from the terminal element 5 of the slot 4. In such'an integral grate-fall as shown'in Fig. 1, this terminal element 5 is obviously continuous and without any break or crevice from one side of the grate-fall, independent guard 'members slot to the other, so there is no crack, however minute, in which fibrous material may lodge.

- As stated, the space 9 between the circurnfei' so arranging the saw relatively to the terminal element of the grate-fall within the range above suggested, it is found that the saw teeth sweep the end of the slot itself clean, even though the teeth do not actually touch such terminal element. It seems probable that, with this very close spacing, the current of air driven forward by the tip of the tooth suffices to clean the eX-' treme end of the slot, even though the tooth tip does not come into actual-physical contact with the end wall of the slot.

In Fig. 3 a slightly different form of grate- This guard extends down substantially'to the gin ning point, and its lower edge may, if desired, be provided with recesses having concavely curved ends like those shown in Fig. 1, each recess, being of a width substantially equaling that of the slot 5 with which the recess registers. The curved end surface 5*, which forms an integrally continuous terminal element for the slot i is spaced from the periphery of the saw in the same Way as the surface 5 of Figs. 1 and 2, so that the effective end of the slot is always swept clean of fibrous material. v

In this arrangement, as in that of Figs. 1 and 2, a clear unobstructed space of increasing capacity is provided just above and to the rear of the ginning point. In this construction the upper ends of the bars I are received behind the its front face substantially flush with the rear.

surface of theinner wall of the roll box, .while the under surface ofthe member 2.] is smooth, preferably polished, and closely fits against the sides and rear surfaces of the bars is. Thus as in the arrangement of Fig. 1, thereare no corners, projections, recesses or obstructions such as to oppose the flowof the lintcarrying air stream and which might cause the collection of lint either mechanically or; electricallyat this point. I

In Fig. 5 a further modification is-showniin which the grate-fall comprises the independent bars I having their opposed edges recessed to provide the slots 4 for the saws ,6. These slots between the bars terminate at the points and where the bars meet at their upper endsa joint I2 is formed. Instead of a continuous guard extending transversely across the width of, the 13 are provided, each such guard member, if desired, being set into the grate -bars so as t0 .lie flush with their front surfaces, and, extending across vso from one grate-bar to the next, said guard members each being firmly united to one grate-bar at least, for example by pins, spot welding, or the like. The lower edges of these elements I3 are integrally continuous from one side of the slot to the other and form the effective terminal element of the slot. The saw blade is set close to this terminal element (within the range above specified), said element, in this instance, being shown as being substantially straight and parallel to the axis of the saw cylinder. The operation of the saw in keeping theend of the slot clean is the same as previously described.

Obviously other modes of constructing the grate-fall may be employed, although, as above stated, it is preferred for best results to terminate each slot by means of an element which is integrally continuous, that is to say, without any joint, crack or crevice, from one side of the slot to the other, and I wish it to be understood that all such modifications of the arrangement herein disclosed as may fall within the scope of the appended claims are to be regarded as within the purview of the invention.

I claim:

1. Apparatus for delinting cottonseed comprising a grate-fall and a rotating saw cylinder having blades turning in slots in the grate-fall, the width of each such slot, adjacent to the ginning point where the saw teeth pass downwardly through the grate-fall, not exceeding the width of the slot at other points, a transversely continuous terminal element for each of said slots, each such terminal element having walls converging toward the extreme end of the slot, and means for rotating the cylinder relatively to the rate-fall, the parts being 50 arranged that the tips of the saw teeth move between said convergent walls of the respective terminal elements and pass the extreme ends of the respective slots as defined by said terminal elements at a distance of the order of one-sixteenth inch, thereby at all times to keep the ends of the slots clear of accumulations of material.

2. Apparatus for delinting cottonseed comprising a grate-fall and a rotary saw cylinder having blades which turn respectively in slots of the grate-fall, the width of each such slot, adjacent to the ginning point where the saw teeth pass downwardly through the grate-fall, not exceeding the width of the slot at other points, a transversely integral terminal element for each slot, each terminal element being concavely curved toward the edge of its saw so as to narrow the slot near its end, and means for rotating the saw cylinder relatively to the grate-fall, the parts being so arranged that the saw teeth of a given saw move within the concavity of the corresponding terminal element with the tips of the teeth as close to the extreme ends of the respective slots as defined by said terminal elements as is practicable without actual contact of the teeth with said terminal elements, thereby at all times to keep said slots free from accumulations of material.

3. Apparatus for delinting cottonseed comprising a grate-fall and a rotating saw cylinder having blades turning in slots in the grate-fall, the width of each such slot, adjacent to the ginning point where the saw teeth pass downwardly through the grate-fall, not exceeding the width of the slot at other points, a transversely continuous terminal element for each slot, each said element being concave toward the edge of its respective saw, means for rotating the saw cylinder,

thetparts being so arranged that the saw teeth of a given saw move within the concavity of the corresponding terminal element and so close to the extreme end of the slot as defined by said terminal element as at all times to keep said slots clean of accumulations of material, and a rigid support for the upper part of .the grate-fall, said support having a smooth under surface so shaped as to provide a rearwardly flaring space immediately above and to the rear of the ginning point into which the lint may pass without encountering elements such as might interfere with the free movement of lint through such space.

4. Apparatus for delinting cottonseed comprising a grate-fall and a rotary saw cylinder having blades which turn respectively in slots of the grate-fall, the width of each such slot, adjacent to the ginning point where the saw teeth pass downwardly through the grate-fall, not exceeding the width of the slot at other points, a transversely integral terminal element for each slot, said element substantially defining the ginning point and being so shaped as to provide a narrow terminus for the slot, means for rotating the saw cylinder relatively to the grate-fall, the parts being so arranged that the saw teeth of any given saw move within the narrow terminus of the corresponding slot and with the tips of the teeth spaced approximately one-sixteenth of an inch from the extreme end of the slot as defined by said terminal element thereby at all times to keep the slots free from accumulations of material, and a rigid support for the upper part of the' grate-fall, said support having an under surface so shaped as to form a vertically flaring space immediately above and to the rear of the ginning point through which the lint may pass without encountering rough surfaces upon which it might collect.

5. Apparatus for delinting cottonseed comprising a grate-fall and a rotary saw cylinder having blades which turn respectively in slots of the grate-fall, the width of each such slot, adjacent to the ginning point where the saw teeth' 'pass downwardly through the grate-fall, not exceeding the width of the slot at other points, a transversely integral terminal element for each slot, said element defining the ginning point and being concave toward the corresponding saw blade, means for rotating the saw cylinder relatively to the grate-fall in such a way that the saw teeth of any given saw pass through the narrow end of the slot defined by the concavity of the terminal element and with the tips of the teeth at a distance of the order of one-sixteenth of an inch from the extreme end of the slot as defined by said terminal element.

6. A saw gin for delinting cottonseed compris ing a saw cylinder having blades, a grate-fall having slots in which the respective blades turn, the width of each such slot, adjacent to the ginning point where the saw teeth pass downwardly through the grate-fall, not exceeding the width of the slot at other points, each such slot being terminated by a stationary transversely integral element defining the ginning point, and bearings for the saw cylinder so arranged relatively to the grate-fall that the tips of the teeth of any given saw blade describe a circumference which is spaced from the terminal element of its slot a distance of the order of one-sixteenth inch, whereby the teeth of the saws sweep clean the effective ends of the slots, and a rigid rail supporting the upper part of the grate-fall, said supporting rail having a smoothly finished under surface including an upwardly and rearwardly sloping face providing a clear space which flares upwardly immediately to the rear of the ginning point.

7. A saw gin for delinting cottonseed-comprising a saw cylinder, a grate-fallhaving slots in which the respective saw blades turn, the width of each such slot, adjacent ,to the ginning point where the saw teeth pass downwardly through the grate-fall, not exceeding the width of the slot at other points, each such slot being terminated by a stationary transversely integral element concave toward the edge of the saw and defining the ginning point, and bearings for the saw cylinder so arranged relatively to the gratefall that the tips of the teethof any given'saw blade describe a circumference which is as close as practicable to the terminal element of its slot and within the concavity thereof whereby the teeth of the saw sweep clean the effective end of the slot.

,8. A saw gin for delinting cottonseed comprising a saw cylinder, a grate-fall having slots in which the respective saw blades turn, the width of each such slot, adjacent to the ginning point where the saw teeth pass downwardly through the grate-fall, not exceeding the width of the slot at other points, each such slot being terminated by a stationary transversely integral element concave toward the edge of the saw and defining the ginning point, and bearings for the saw cylinder so arranged relatively to the gratefall that the tips of the teeth of any given saw blade describe a circumference such that they move within the concavity of the terminal element of the respective slot so that the teeth of I the saw sweep clean the effective end of the slot, and a railsupporting the upper part of the V grate-fall, said rail having under surfaces which are smooth, free of obstructions or crevices, and which define the top of an upwardly flaring space into which lint may pass without danger of being obstructed or caught by contact with the rail.

9. A saw gin for delinting cottonseed, said gin having a saw cylinder, a grate-fall comprising an integral piece of sheet material having substantially parallel slots, therein in which therespective blades turn, the .Width of each such slot, adjacent to the ginning'point where the saw teeth pass downwardly through the grate-fall, not exceeding the width ofthe slot at other points, each slot having an end wall forming a' transversely integral terminal element whose walls converge in width toward the extreme end ofcthe slot, the

saw cylinder and grate-fall being so relatively disposed that the tips of the teeth of any given saw move in a circumferential path which lies between the convergent walls of the terminal .element and is at a distance of the order of onesixteenth of an inch from the extreme end 'of the slot. v

10. A saw gin for delinting cottonseed, said gin having a saw cylinder, a grate-fall comprising an integral piece of sheet material having substantially parallel slots therein in which the respec-c tive saw blades turn, the width of each such slot, adjacent to the ginning point where the saw teeth pass downwardly through the grate-fall, not exceeding the width of the slot at other points, each slot having a curved end wall forming an uninterrupted terminal element concave toward the edge of the corresponding saw blade;

and bearings for the saw cylinder so arranged that the tips of the teeth of any given saw blade describe a circumferential path which is within the concavity of the terminal element of the slot and at a distanceof the order of one-sixteenth of an inch from the extreme end of the slot, there by to cause the teeth of the saws to sweep clean the ends of the slots.

11'. A grate-fall comprising a series of parallel

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