US 3154263 A
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Oct. 27, 1964 H. F. FISCHER, JR., ETAL 3, 5 6
SELF-CENTERING con. CRADLE 2 Sheets-Sheet 1 Filed May 8, 1963 INVENTORS. HARRY Ff FISCHER. JQ. BLYAWRE/VCE 4.//09D,Jfi.
Oct. 27, 1964 H. F. FISCHER, JR.. ETAL 3,154,263}
SELF-CENTERING COIL CRADLE Filed May 8, 1963 2 Sheets-Sheet 2 INVENTORS.
"22 HARRY F2 FISCHER JR.
26 EL v ATTORNEKS BYLAWAENCE A. HOOQJR.
United States Patent Office 3,154,253 Patented Oct. 27, 1964 3,154,263 SElZF-CEN 66E CRADLE F. Fischer, 313, and Lawrence A. Hood, .lr., Pittsburgh, Pa, assign-01's to Zedco (30., inc., Ettshurgh, Ta, a corporation of Pennsylvania Filed May 8, 1953, Ser. No. 278,971 9 Claims. (Cl. 24-278.7}
This invention relates to roller cradles for supporting coils of strip material while they are being wound or unwound, and more particularly to cradles designed to keep the coils centered thereon.
in coiling or uncoiling a length of strip material it is common practice to place or form the coil on a pair of parallel horizontal rollers so that it can rotate. As the coil rotates, it generally will move lengthwise along the rollers slowly toward one end or the other, so stops or guides usually are provided to restrain the endwise movement of the coil. However, such guides are objectionable because they are apt to damage the edges of the strip engaging them. One solution to the problem has been to make one of the cradle rollers in a special form that tends to keep the coil from moving endwise in either direction from a centered position, but such a roller is relatively complicated and expensive.
it is among the objects of this invention to provide a coil cradle which will automatically keep a coil centered thereon, which does not require end guides, which uses conventional rollers and which is simple and inexpensive in construction.
In accordance with this invention, one of a pair of laterally spaced substantially horizontal rollers is journaled at its ends in a pair of bearings mounted in fixed position. The other roller, which is spaced from the first one just far enough to permit a coil of strip material to rest on both rollers, also has its ends journaled in a pair of bearings, but these hearings are mounted on a supporting member which is rockably supported in such a manner that it will be tilted lengthwise by a coil rotating on the rollers and starting to move lengthwise thereof from a central position. The tilting roller is rotated directly or by the coil in such direction that its top turns toward the other roller so that the tilted coil will reverse its direction of axial movement and return to centered position on the rollers.
The invention is illustrated in the accompanying drawings, in which PK}. 1 is a plan view of our coil cradle;
FIG. 2 is a side view thereof with a coil resting on the cradle;
FIG. 3 is an end view of the cradle ant. coil; and
FlGS. 4, 5 and 6 are views, similar to FIGS. 1, 2 and 3, of a modification of the invention.
Referring to FIGS. 1 to 3 of the drawings, a pair of substantially parallel horizontal rollers 1 and 2 are disposed above a suitable base 3. The ends of roller 1 are journaled in bearings 4, which are rigidly mounted on a support 5 fastened to the base. Preferably, this roller is driven in any suitable manner, such as by a chain and sprocket drive 6 mounted on an extension of the roller neck.
It is a feature of this invention that the other rol er 2 is mounted for tilting or roclc'ng movement in a vertical plane extending lengthwise of the roller. Accordingly, the ends or the roller are journaled in bearings 8 rigidly porting member 9, such as a thick plate, which is spaced mounted on the opposite ends of an elongated rigid suplaterally from the support 5 beneath the other I The plate is supported above the base by means disposed midway between the ends of the plate and which rockaoly support it on a transverse axis. For best results, this axis should be as high as possible. In the drawings the rockable support is formed in part by lugs ill projecting outward from the upper ends of brackets 11 extending upward from the opposite sides of the plate. As shown in FIG. 2, each lug is tapered downward to form a knife edge that rests in a V notch 12 in the top of a bearing block 13 rigidly mounted on the base beside the plate. The taper of the notches is flatter than that of the lugs so that the latter can rock in the notches to permit plate 9 and roller 2 to tilt lengthwise.
To normally hold the tilting roller level when there is no coil on the cradle, a vertical coil spring 14 may be compressed between each end of plate 9 and the underlying base. These springs may be held in place by pins 15 projecting up into them from the base, but the upper ends of the pins are spaced from the overlying plate far enough to allow it to tilt sufiiciently for its intended purpose. On the other hand, the pins also function as stops to prevent the plate from rocking too far in either direction, such as when a coil is being placed on the cradle or removed from it.
Assuming that a coil C of strip material, such as metal strip, has been placed on the cradle in centered position so that the tilting roller 2 is horizontal, the strip is unwound from the coil in a direction that will cause the top of roller 1 to turn away from the other roller. Either roller, or both can be driven, but it is easiest to drive roller 1 because it has stationary bearings 4. As the coil obviously rotates while it is being unwound, it will almost certainly attempt to move axially along the rollers. However, because or" the construction of the cradle any such movement of the coil will start to tilt roller 2 and the coil itself, whereupon the coil will reverse its axial movement and move toward the higher end of the tilted roller and back to centered position. It may pass that position, but.
if it does, the tilting roller and coil will tilt in the opposite direction so that the coil again will return toward centered position on the cradle. Although the reason why the tilted coil travels toward the high end of the tilted roller is not fully understood, it apparently is because engagement between the tilted coil and the horizontal roher tends to change from a horizontal line contact to a point contact that describes a helical path around the coil as it rotates that progresses toward the lower end of the coil. Since the horizontal roller cannot move axially, this screwing of the tilted coil against the horizontal roller must move the coil axially along both rollers away from the lower end of the tilted roller.
The weight of the coil will tend to push roller-supporting plate 9 away from support 5, so to prevent the plate from binding against outer bearing block 13 various means can be used, such as a thrust bearing, or rollers engaging the outer side or" the plate. A simple way of solving the problem is to connect the inner side of plate 9 to support 5 by a pair of flexible or pivoted tension links 16. To provide for lateral movement of the plate toward the support when the plate tilts, there must be some clearance between the plate and the two bearing blocks 33.
This cradle becomes more sensitive to axial movements of a coil on it as the weight of the coil on the tilting roller increases relative to its weight on the other roller. There.
fore, it is desirable to locate roller 1 at a higher elevation than the other roller in order to cause the coil to put more weight on the tilting roller, as shown in FIG. 3.
it will be seen that in actual practice there can be very little tilting of the one roller because the moment the coil begins to tilt it, the coil will start to move back in the opposite direction. Consequently, in practice the tilting roller merely rocks back and forth as the coil starts to move axially first in one direction and then in the other, with the result that the coil stays substantially centered on the cradle. However, as long as the pivot point for the tilting coil is below the coils center of gravity, there will be some overshooting of center as the coil moves back and forth along the rollers. This is because a tilted coil will have to climb past the center point before the tilting roller will level out and then the roller will quickly tilt in the opposite direction. This problem is solved to some extent by springs 14, which reduce the degree of roller tilting, but overshooting can be practically eliminated by the embodiment of the invention shown in FIGS. 4 to 6.
In the modification shown in FIGS. 4, 5 and 6, one roller 21 is journaled in permanent horizontal position in bearings 22 on a support 23 as before, but the supporting member or plate 24 for the other roller 25, instead of being carried by central pivot bearings, is mounted on two sets of wheels 26 or the like near its opposite ends. These wheels, in turn, travel on longitudinally concave track means 27 mounted on the base 28. The track means have longitudinally concave upper surfaces lying in an arc of a circle, the axis of which coincides as closely as possible with the center of the full coil supported by the rollers. Therefore, when the rotating coil starts to move axially from centered position on the rollers toward one end or the other, one end of supporting plate 24 will be pressed down and that will cause the wheels to roll toward the opposite end of the tracks, thereby tilting the plate and roller 25 and the coil around the axis of the track are. The result of this tilting will be the same as that described earlier; the coil will move axially toward the higher end of the roller and therefore return to centered position on the rollers, which will level the tilting roller. In doing this the coil will not have to pass centered position, because when the center of the coil reaches that position it will coincide with the axis of the track arc. This arrangement therefore is more sensitive than the one first described.
An important feature of this embodiment of the invention is that the coil cradle can be made to compensate automatically for changes in the weight of the coil. This is done by making the track means 27 from a pair of laterally spaced spring steel plates, so that the greater the weight on them the more they will be flattened. The initial curvature of the tracks is such that when a full coil is placed on the rollers the tracks will be flattened to the point where the axis of the track are will pass approximately through the center of the coil. As the coil is unwound and it therefore becomes lighter, the tracks will be permitted to gradually bow upward to shorten their radius of curvature, whereby the axis of the track arc and the center of the coil will remain close together.
According to the provisions of the patent statutes, we have explained the principle of our invention and have illustrated and described what we now consider to represent its best embodiment. However, we desire to have it understood that, Within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.
1. A self-centering cradle for a coil of strip material, comprising a pair of laterally spaced substantially horizontal rollers, a pair of bearings for the ends of each roller, stationary supporting means for one pair of bearings, a supporting member for the other pair of bearings, and means rockably supporting said member for lengthwise tilting by a coil rotating on said rollers and starting to move lengthwise thereof from a central position, the tilting roller being rotatable in such direction that its top turns toward the other roller so that a tilted coil will travel axially toward the high end of the tilted roller.
2. A cradle according to claim 1, in which the top of the horizontal tilting roller is at a lower level than the top of the other roller.
3. A cradle according to claim 1, including means for driving one of said rollers in such direction that the bottom of the coil will travel from the tilting roll to the other roller.
4. A self-centering cradle for a coil of strip material, comprising a pair of laterally spaced substantially horizontal rollers, a pair of bearings for the ends of each roller, stationary supporting means for one pair of bearings, a supporting member for the other pair of bearings, and means rockably supporting said member on a transverse axis midway between the ends thereof, whereby said memher will be tilted lengthwise by a coil rotating on said rollers and starting to move lengthwise thereof from a central position, the tilting roller being rotatable in such direction that its top turns toward the other roller so that a tilted coil will travel axially toward the high end of the tilted roller.
5. A cradle according to claim 4, including springs beneath said supporting member tending to hold it horizontal.
6. A self-centering cradle for a coil of strip material, comprising a base, a pair of aligned bearings mounted thereon, a roller journaled in said bearings, an elongated rigid supporting member spaced laterally from said roller, means on said base midway between the ends of said member rockably supporting it above the base on a transverse axis so that it can tilt lengthwise, a pair of aligned bearings mounted on the ends of said member, a roller journaled in said last-mentioned bearings, whereby a rotating coil supported by the rollers will tilt the roller supported by said rockable member if the coil starts to move axially from a central position, and means for driving said first-mentioned roller in such direction that its top turns away from the other roller.
7. A self-centering cradle for a coil of strip material, comprising a pair of laterally spaced substantially horizontal rollers, a pair of bearings for the ends of each roller, stationary supporting means for one pair of bearings, a supporting member for the other pair of bearings, Wheels supporting said member for longitudinal movement, and longitudinally concave track means for said wheels, whereby the wheels will run along the track means and tilt said member when a coil rotating on said rollers starts to move lengthwise of the rollers from a central position, the tilting roller being rotatable in such direction that its top turns toward the other roller so that a tilted coil will travel axially toward the high end of the tilted roller.
8. A coil cradle according to claim 7, in which said track means is bowed lengthwise and resilient and changes its curvature in accordance with the weight supported by it;
9. A coil cradle according to claim 7, in which said track means includes two laterally spaced bowed spring plates.
References Cited in the file of this patent UNITED STATES PATENTS 2,122,674 Wardle July 5, 1938 ha e...