US 2989265 A
Description (OCR text may contain errors)
June 20, 1961 w. T. sELsTED 2,989,265
TAPE GUIDING SYSTEM Filed May s1, leso IN V EN TOR. /g l/PM rf@ Z7 Sas/*0 BY Mg. Lum
United States Patent 2,989,265 TAPE GUIDING SYSTEM Walter T. Selsted, Woodside, Calif., assignor 'to Ampex Corporation, Redwood City, Calif., a corporation 'of California Filed May 31, 1960, Ser. No. 32,803 7 Claims. (Cl. 242-76) The present invention relates to a web handling system and in particular to a system for accurately feeding pliant magnetic tape from a storage roll to a slitting device at a high rate of speed.
For convenience, magnetic tape is usually processed and stored in rolls having a larger width than is required in use. The wide rolls of tape must then be longitudinally slit or cut into strips of desired uniform width. When the tape is of a limp material, such as present-day magnetic tape, maintenance of proper alignment during slitting is diicult, and such diculties are considerably pronounced during a high speed slitting operation because of the lateral displacement of the tape material to one side or the other of the wide roll. Because of the limpness of the tape material, laterally applied pressure does not overcome the sideways displacement of the material, and conventional roller and guide combinations do not provide proper alignment as `is possible with stiff materials.
It is therefore an object of the present invention to provide a new and improved feed system for material in tape form.
Another object of the invention is to provide a high speed tape handling system for delivering magnetic tape to a slitting device with accurate alignment.
A further object of the invention is to provide a feed system for tape of =a limp material wherein the lateral and radial position o-f the tape at the slitting device is established accurately regardless of the degree of limpness of the material. 1
In brief, the system of the present invention guides tape from a wide roll under a rst hollow cylinder and over a second hollow cylinder to a slitting device. In accordance with the invention, the two cylinders may be in the form of hollow guide tubes which are mounted in vertical spaced-apart relationship with the second being in substantially parallel alignment with the rst and with a storage roll of the tape. To compensate for lateral deviations of the tape the irst guide tube is centrally mounted'as a pivotal joint so as to have freedom of movement in two planes. The second guide tube is also pivotally mounted about a central point, but is movable only about an axis extending transverse to the tube and parallel to the direction of movement of the tape. Each of the tubesis provided with a plurality of apertures along the surface adjacent to the tape and is connected to a source of air under pressure so that the tape is supported by a lm of air. As the wide roll is fed from the roll toward the slitting knives, the guide tubes are moved automatically in a balanced fashion to introduce cornpensatory twists in the tape to cause the edges of the `tape to approach the knives in proper alignment.
Other objects and advantages of the present invention will be apparent from the following description, considered together with the accompanying drawing, in which:
FIGURE l is a simplied perspective representation of a system in accordance with the invention;
, ,FIGURE 2 is a perspective view schematically illustrating the structural arrangement of a tape handling system in accordance with the invention; and
FIGURE 3 is a simplified schematic illustrating the operation of various elements employed in the arrangement of FIGURE 2. g
In FIGURES 1 and 2, there is shown a roll 11 of tape lCC material 12 wound upon a shaft 13. Extended ends 14 of the shaft 13 are journaled for yfree rotation in a suitable rigid frame, which is not shown in the drawing for ease of illustration, and which may be of any convenient form.
To maintain desired lateral alignment of the tape material 12, as unwound from the roll 11, there is provided a lirst hollow cylinder or tube 16 pivotally mounted with respect to the referenced rigid frame. Thus, a bracket arm 17 (best seen in FIGURE 2) is mounted in fixed relation, spaced apart from and parallel to the shaft 13, with a suspension rod 18 suitably mounted at one end to the bracket arm 17, substantially midway of the length of the shaft, and extended vertically downward to terminate in a ball 19. The cylinder 16 is provided with a socket 21 disposed midway of the length thereof to engage the ball 19 so as to provide a pivotal ball joint coupling. The rst tube 16 is free to rotate in both horizontal and vertical planes (as seen in FIGURE 3) about its central pivot point.
Also, to correct the radial alignment of the tape material 12, -a second hollow cylinder or tube 26 is centrally mounted for rotation about a central pivot point lying on an axis 27. The axis 27 is transverse to the longitudinal center-line of the second tube 26 and parallel to a line extending from the ball 19 and socket 21 combination to the midpoint of the shaft 13. For proper guidance of the tape material 12 the second tube 26 is vertically spaced above the rst tube 16. Rota-tion of the second tube 26 about theaxis 27 is provided by a hollow support shaft ,28 mounted at one end to the tube 26, midway of its length, and extended along the axis 27A away from the roll 11lto rotatably engage a member (not shown) affixed, to the referenced frame, as by ,spacedapart bearings 29. Two guide rings 30 are mountedon the second tube 26 and spaced apart the width of the tape material 12 to provide lateral restraint.
The first and second tubes 16and 26 are both mounted in a manner preventing rotation about their longitudinal axes, land a plurality of apertures 31 and 32 are provided through each tube 16 and26 respectively over the surface contacted by the tape material 12. One end of the cylinder 16v is closed by aplug 33, and air under pressure is applied to the other end of the tube 16, as by a hose connection 36. Air under pressure is also supplied to the second tube 26 througha hose'37 and the hollow support shaft28. It is understood that the tube 26 is sealed at both ends to prevent air escape from the ends. Y rected through the apertures 31, 32 from within the tubes 16 and 26 creates a lilm of air which supports the tape,
material 12, without friction, away from the surface of the respective cylinders 16 and 26. A similar result may be obtained by vforming the cylinders 16 and 26 with a porous material at the contact surface, rather than the apertures 31 and 32.
From the second tube 26 the tape 12 moves toward slitting knives 40, which in the present example are preferably in the form of paired rollers having peripheral` cutting edges, with the tape moving between the rollers of each pair. All ofthe knife rollers on each side ofthe tape 12 may be mounted ,onV a common retatable shaft wound up on a ydifferent takeup reel 42 driven by an ex-v' ternal source (not shown).
With the tape material 12 moving betweenY the roll 11 and the knives of the slitting device 40 infthe manner described,- the `ends of the first tube 16 'are free to move arcuately about the pivot point at the ball 19 and socket 21 combination. The first tube 16 may have components of arcuate motion in either a horizontal direction, a vertical direction, or both directions. Thus, should the tape material 12 be laterally displaced on' the roll 11, or tend to creep to one side of the first tube 16, the resulting unbalance of forces at the first tube 16 causes a twist which compensates for the misalignment. The compensation for misalignment is completed by the movement of the second tube 26 in conjunction with the first guide tube 16. Reference may be made to the simplified representation of FIGURE 3 for a better understanding of these relationships. FIGURE 3 shows in exaggerated form the way that the guide tubes 16 and 26 may be displaced for a given lateral displacement of the tape 12. from the roll 11 as viewed from above the roll in FIGURE 1, looking toward the slitting knives. As seen in FIGURE 3, alateral tape displacement on one side draws thefirst guide tube 16 toward the supply roll (out of the paper) and also upward on that side. On theopposite side of the pivot point the tube 16 moves down and away. A1- though the amount of tape on one side (the left in the example of FIGURE 3) is greater and the lever arm is effectively longer, the sharper bend on the other (right) side introduces higher forces so that at some point the extent of the pivot places the total moments on each side of the pivot point in balance. Here it should be recognized that the balance is also affected by the position assumed by the second guide tube 26.
In the present example, the second guide tube 26 pivots down on the right side (as seen in FIGURE 3) because the tube 26 is drawn down by the sharper tape angle caused by the outward movement of the first tube 16 at that side. If the second tube 26 were fixed, the tape 12 would slide somewhat to the left, in this example. Because the second tube 26 may rotate in one plane, however, it introduces an added twist which further assists in aligning the tape 12 with the positions desired for the side margins.
At this point, two additional factors should be noted. First, the tape 12 from the roll may have a lateral displacement on the roll, or a lateral tendency between limits, but may be considered to be retained at least momentarily by frictional forces in the path which it assumes. Therefore, the tape will not tend to ride uncontrollably in a lateral direction off the guide tubes 16 and 26. Second, although only a slight constraint of the tape 12 at the sides is feasible, the constraint provided by the rings 30 on the second tube 26 is suicient with this balancing arrangement to maintain the side edges of the tape 12 in the desired relationship to the slitting knives.
Thus, movement of the tape 12 in a lateral direction introduces twisting in two dimensions at the first tube 16 and in one dimension at the second tube 26 which brings the edges of the tape back into line. The action is virtually instantaneous and free of frictional forces. Deviation of the tape in a direction opposite to that described results in twists which are also opposite to provide the needed correction. By this means high speed and automatic control of a limp magnetic tape is made feasible.
There has been describedherein a system for guiding a wide roll of tape utilizing spaced guide tubes. A first guide tube is movable in two planes, while a second guide is pivotable only about an axis which is transverse to such second tube and parallel to the direction of movement of the tape. In addition, the guide tubes have means for supplying air pressure so that the tape is oated on an air film. The guide tubes automatically align the tape roll with relation to slitting knives utilized to severe the tape longitudinally in the direction of tape movement.
What is claimed is:
i 1-. A system for feeding a pliant4 magnetic tape material hom a supply -roll into precise alignment with a slitting device comprising: a rst guide member pivotally mounted at a central point to have freedom of movement in two dimensions; and a second guide member pivotally mounted at a central point to have freedom of movement in one dimension, the first and second guide members being positioned substantially transversely relative to the direction of feed and adjacent to the'magnetic tape so as to provide two angles therein, the second guide member being closest to the slitting device.
2. A system for feeding a pliant magnetic tape at high speed from a supply roll into a tape slitting device despite lateral displacement of the tape comprising the combination of: a pair of guide members positioned along the path of the tape between the supply roll and the slitting device, the guide members each being pivotally mounted at a central pivotal point with respect to the intended path of the magnetic tape, and the guide members being positioned to provide two substantially right angle turns in the magnetic tape between the supply roll and the slitting device.
3. In a high speed feed system for accurate delivery of tape material from a roll of su'ch material to a receivingpoint along a projected linear path, the combination comprising: rotatable means for centrally mounting said roll transverse to said path; first guide means centrally and pivotally mounted transverse to said path in spacedapart relation with said roll to engage a first surface of said tape; second guide means centrally and rotatably mounted transverse to said path with the center of rotation extended along said path, said second guide means being transversely spaced apart from said first guide means to engage a second surface of said tape; and means coupled to said first and second guide means to provide a film of air between said tape and each of said guide means.
4. In a high speed feed system for accurate delivery of tape material from a roll of such tape to a receiving point along a projected linear path, the combination comprising: rotatable means for centrally mounting said roll transverse to said path; a first hollow cylinder centrally mounted transverse to said path in spaced-apart relation with said roll to engage a first surface of said tape, said first cylinder being mounted to pivot about an axis transverse to said path; a second hollow cylinder centrally mounted transverse to said path to engage a second surface of said tape, said second cylinder being transversely spaced apart from said first cylinder on said path and being rotatable about an axis extended along said path, each of said first and second cylinders being closed at one end and having a porous surface in contact with said tape; and means for connecting compressed air to the respective open ends of said first and second cylinders to provide a film of air between said tape and said cylinders.
5. The combination of claim 4 wherein said first cylinder is pivotably mounted by a ball joint and saidsecond cylinder is rotatably mounted by a journaled shaft.
6. In a high speed feed system for accurate delivery of tape material from a roll of such tape to a receiving point along a projected linear path, the combination comprising: a rotatable shaft centrally mounted on said path transverse thereto for supporting a roll of said tape; first guide means having a centrally disposed ball joint for pivotably supporting such first guide meanson said path in spaced-apart relation to said rotatable shaft to engage a first surface of said tape and minimize lateral movement thereof; second guide means having a centrally mounted shaft extended transversely along said path, `said second guide means being rotatable about the longitudinal axis of said centrally mounted shaft and spaced from said first guide means to engage a second surface of said tape for compensating radial movement thereof; and means coupled to said rst and second guide 5 means for providing `substantially friotionless transport of said tape thereover.
7. In a high speed feed system for tape material, the combination comprising: a roll of tape Wound on a shaft mounted for free rotation about the longitudinal axis thereof; a first cylinder pivotably mounted about a point lying on a line extended transverse to said shaft at the midpoint of the length thereof, said point being midway of the length of said rst cylinder; a second cylinder mounted above said rst cylinder With respective midpoints ofthe lengths thereof being vertically aligned, said second cylinder being rotatable about an axis extending through the midpoint of said second cylinder and transverse to a line between the respective midpoints of said 6 rst and second cylinders, the rtape of said roll being extended under said lirst cylinder and over said second cylinder for accurate alignment of the tape; #and means coupled to said rst and second cylinders to provide a film of air lbetween said tape and said cylinders.
References Cited in the tile of this patent UNITED STATES PATENTS 698,125 Messter Apr. 22, 1902 1,189,611 Morse July 4, 1916 2,837,330 Lawrance et al .Tune 3, 1958 FOREIGN PATENTS 327,360 Great Britain Apr. 3, 1930