Bobbin transfer tray

Abstract: The present invention provides a bobbin transfer tray that has a simple structure and is easy to assemble. The present invention is intended for a bobbin transfer tray T having, on the outer circumferential surface 8 of a peg 2, pressing members pressing the core tube 3 of a bobbin B fit over a peg 2, wherein the pressing members consist of spring plates 9 covering the outer circumferential surface 8 of the peg 2, bent portions 10 are provided at both side edges of the spring plates in the circumferential direction, the peg 2 has slits 13 into which the bent portions 10 are inserted, fixed portions 16 that elastically hold the inner surfaces 15 of the slits using the bent portions 10 are formed at the top of the spring plates 9, and the lower parts of the spring plates 9 are projected outward radially from the peg 2.

Description: The present invention relates to a bobbin transfer tray according to the preamble of claim 1. Such a tray is known from DE-A-4110284. The spring means of this tray is a tube having a longitudinal slit and being helically bent. One of the side edges of the tube has a bent portion engaging into a slit of the peg. The problem underlying the present invention is to provide a bobbin transfer tray having a structure that allows the spring means to be installed on the peg by one action and the tray to be assembled easily. This problem is a accomplished by the features defined in the characterizing portion of claim 1. The proposed structure allows both side edges of the spring plate to be fully inserted into the slits, so that sharp spring plate edges do not damage the lower end and inner circumferential surface of a core tube. The middle area between the bent portions of the spring plates be curved along the outer circumferential surface of the peg, wherein the curvature at the top of the middle area of the spring plates is equal to that of the outer circumferential surface of the peg, and the curvature of the inner circumferential surface of the lower part differs from that of the outer circumferential surface of the peg. Such a structure allows the lower part of the middle of spring plates to be tilted and fanned out in the length direction of the peg, and the lower part to be closed radially inward when the bobbin is fit, so that reactive force due to longitudinal deformation presses the bobbin. Because the lower part of the spring plates radially collapses from outside, thus deforming the plates in the circumferential direction when the bobbin is installed, the resulting reactive force also presses the bobbin. Brief Description of the Drawing Figure 1 is a perspective view showing an embodiment of a bobbin transfer tray according to the present invention. Figure 2 is a longitudinal section of a tray. Figure 3 is the cross section of the tray, taken along line III-III in Figure 2. Figure 4 is the cross section of the tray, taken along line IV-IV in Figure 2. Figure 5 is a cross section of a tray with a bobbin installed, which is equivalent to the cross section taken along line IV-IV in Figure 2. Figure 6 shows an unfinished spring plate. Detailed Description of the Preferred Embodiments Referring to the drawings, a preferred embodiment of the present invention is described below. As shown in Figures 1 and 2, a bobbin transfer tray T, with a cylindrical peg 2 integrally provided in an upright position in the center of a discoid base 1, is adapted so that a core tube 3 of a bobbin B is fit over the peg 2 to support the bobbin B in an upright position. The base 1 and the peg 2 are formed integrally from plastic. At the lower end of the peg 2, a step 4 having a larger diameter than the peg 2 is provided, on top of which is positioned the lower end 5 of the core tube 3. The top of the peg 2 is formed into a cone shape. A center hole 6 is drilled from below in the base 1 and peg 2. The hole provides a suction path to find a yarn end. A suction port 7 is provided to communicate through the top of the peg 2 with the center hole 6. When suction is provided through the center hole 6, with the bobbin fit over the peg 2, negative pressure propagates through the suction port 7 and core tube 3 to the top of the core tube 3, so that a yarn end at the top is sucked. Pressing members in the form of spring plates 9 are provided to press the core tube 3 from inside on the outer circumferential surface 8 of the peg 2. The three spring plates 9 are installed along the circumferential direction of the peg 2 and curved in the circumferential direction so that the spring plates 9 almost entirely cover the lower part of the outer circumferential surface 8, with the upper part of the surface left partially uncovered. The spring plates 9 are formed by curving rectangular stainless steel plates as shown in Figure 6. In particular, both of their side edges are bent at the chain lines over their entire length in the height direction, toward the side of the peg 2, to form bent portions 10 having a predetermined bend length L. The intermediate part 12 between the bent portions 10 is curved along the outer circumferential surface 8 of the peg 2, as described later. As shown in Figures 3 and 4, slits 13 are formed in the peg 2 along its circumferential direction at intervals of 120 degrees. The slits 13 are intended for insertion of the bent portions 10 of the spring plates 9. The slits 13, which are formed from the bottom of the tray T to the top of the peg 2 along the axis of the tray T, extend into the center hole 6 of the peg. The slits 13 receive both side edges or the bent portions 10 of the spring plates 9, which extend over the entire length in the height direction of the spring plates 9. However, the slits 13 do into the center hole 6 of the peg 2 at the step 4, so that a predetermined wall thickness remains on the side of the outer circumference of the step 4. Because the radial thickness H of the peg 2 is greater than the bend length L of the bent portions 10, the slits 13 have a depth H from the outer circumference 8 that is greater than the bend length L. As shown Figure 3, at the intermediate part 12 at the top 14 of the spring plates 9, the curvature R 1 of the inner circumferential surface 20 of the spring plates 9 is equal to the curvature R o of the outer circumferential surface 8 of the peg 2. Thus, the top 14 of the intermediate parts 12 of the spring plates 9 is in close contact at their top with the outer circumferential surface 8 of the peg 2. The bent portions 10 at the top 14 of the spring plates 9 are inserted into the slits 13, thus elastically holding the internal surfaces of the slits 13. The bent portions 10 at the top 14 therefore provide fixed portions 16 to be secured to the peg 2. The spring plates 9 are so thin that the difference in level between the outer circumferential surface 8 of the peg 2 and the outer circumferential surface 17 of the spring plates 9 is virtually negligible. Because the depth H of the slits 13 is greater than the bend length L of the bent portions 10, the bent portions 10 do not enter the center hole 6 completely. Thus, there are no obstructions in the center hole 6 on which yarn may be caught. As shown in Figure 4, the curvature R 2 of the inner circumferential surface 20 of the spring plates 9 is smaller than the curvature R o of the outer circumferential surface 8 of the peg 2 at the lower part 18 from the top 14 of the intermediate part 12 of the spring plates 12. Thus, the lower part 18 of the intermediate part 12 of the spring plates 9 is separated from the outer circumferential surface 8 of the peg 2, and both sides in the circumferential direction are in contact with the outer circumferential surface 8 of the peg 2. As described above, the bent portions 10 of the lower part 18 of the spring plates 9 is inserted into the slit 13. However, the bent portions 10 do not actually abut the inner surface 15 of the slit 13, and only the edge of the bent portions 10 is in contact with the inner surface 15. In this way, the lower part 18 is able to freely move radially and elastically deform to come in close contact with the peg 2. Strictly speaking, the spring plates 9 are curved so that the curvature of their inner circumferential surface is exactly equal at the top to that of the outer circumferential surface 8 of the peg 2, and becomes progressively smaller in the downward direction. However, due to machining errors, the tops of the spring plates 9 are almost entirely secured in close contact with the outer circumferential surface 8 of the peg 2, and their lower parts are projected away from the outer circumferential surface 8 of the peg 2, so that the lower part can freely and elastically deform. As shown in Figures 1 and 2, after the spring plates 9 are installed, the spring plates 9 tilt and are farther from the peg 2 at their lower parts, so that the three spring plates 9 fan out along the length of the peg 2, thus forming a virtually tapered surface. The effect of the embodiment is described below. To assemble the tray T, it is only necessary to install the three spring plates 9 on the outer circumferential surface 8 of the peg 2. Holding the spring plates 9 against the outer circumferential surface 8 of the peg 2 and pressing the intermediate part 12 of the spring plates 9 causes the spring plates 9 to elastically deform, so that their curvature increases and both their bent portions 10 are inserted into the slits 13, thus bringing the spring plates 9 into close contact with the outer circumferential surface 8 of the peg 2. In this way, the spring plates, which can be inserted into the slots by one action, facilitate tray assembly and eliminate the difficult operations. When the bobbin B is fit over the peg 2 from above to use the tray T, the inner circumferential surface 19 of the core tube 3 comes in contact with the outer circumferential surface 17 of the spring plates 9. Because there is little difference in level between the inner circumferential surface 8 of the peg 2 and the outer circumferential surface 17 of the spring plates 9, the bobbin B is not caught on its downward way. As fitting of the bobbin B progresses, the lower parts 18 of the spring plates 9 are gradually pressed and deformed radially inwardly. The bobbin B finally rests against the step 4, thus completing the bobbin fitting. Figure 5 shows the condition of the lower parts 18 of the spring plates 9 upon completion of fitting. Because the lower parts 18 of the spring plates 9, which are tilted and fanned out, close radially inwardly at their tops 14, the resulting reactive force presses the bobbin B from inside. The spring plates 9, when longitudinally deformed, provide pressure. At the same time that the bobbin B is fit, the inner circumferential surface 19 of the core tube 3 radially collapses the spring plates 9 from outside at the outer circumferential surface 8 of the peg 2, so that they come in close contact with the peg 2. Because the curvature R 2 of the inner circumferential surface of the spring plates 9 changes so that it equals the curvature R o f the outer circumference of the peg 2, such deformation in the circumferential direction also provides a pressing force. Because deformation in both the longitudinal and circumferential directions provides a pressing force, as described above, even a simple structure provides excellent bobbin supporting performance. The outer circumferential surface 17 of the spring plates 9 ensures stable support and prevents bobbin B vibration, because the outer surface 17 of the spring plates 9 comes in surface contact with the inner circumferential surface 19 of the core tube 3. The spring plates 9 are provided around almost the entire circumference of the peg 2, thus providing a pressing force due to surface contact with the entire circumference. In Figure 5, when the core tube 3 collapses the spring plates 9, the inner circumferential surface 20 of the spring plates 9 comes in surface contact with the outer circumferential surface 8 of the peg 2. However, the spring plates 9 may be slightly away from the outer circumferential surface 8 of the peg 2. That is, the spring plates 9 serve their purpose if they can be deformed from their normal shape. In Figure 5, the inner circumferential surface 19 of the core tube 3 is also in close contact with the entire outer circumferential surface 17 of the spring plates 9. However, the inner circumferential surface 19 may be slightly away from the outer circumferential surface 17. The curvature R 2 of the inner circumferential surface of the spring plates 9 may normally be greater than the curvature R o of the outer circumferential surface 8 of the peg 2. The curvature R 2 therefore poses no problem if it differs from the curvature R o. As shown in Figure 4, for the embodiment, the curvature R 2 is smaller than the curvature R o. Thus, the center of the spring plates 9 in the circumferential direction is the farthest point from the peg 2. However, if the curvature R 2 is greater than the curvature R o , both sides of the spring plates 9 are the farthest points from the peg 2. When the bobbin B is fit over the peg 2, the structure is as shown in Figure 5. In such a case, a pressing force is applied to the core tube 3 from both sides of the spring plates 9. The sharp edges of the spring plates 9 do not damage the bottom 15 or the inner circumferential surface 19 of the core tube 3, because both side edges of the spring plates 9 and both their bent portions 10 completely enter the slits 13. In combination with this, the round comers of the spring plates 9 enable safer assembly and easy handling. Because the bent portions 10 do not protrude into the center hole 6, there are no obstructions in the center hole 6, thus ensuring a stable suction. In addition, a yarn end can be smoothly removed from the center hole 6 if it has entered the hole. In such a case, if the yarn end penetrates the center hole 6 relatively deeply, the yarn end is easy to remove because it does not escape through the slits 13.

Claims: A bobbin transfer tray (T) having a peg (2) in an upright position in the centre of a disk shaped base (1) to receive a core tube (3) of a bobbin (B) fit over the peg (2) comprising a spring means received on the peg and engaging rotationally fixed in the circumferential direction but removably into the peg (2) characterized by at least one curved spring plate (9) both side edges of which form bent portions (10) engaging resiliently into longitudinal slits (13) of the peg (2), and characterized in that the curvature (R2) of the inner circumferential surface of the spring plate (9) is smaller than the curvature (R0) of the outer circumferential surface (8) of the peg (2) at the lower part (18) of the spring plate (9). A bobbin transfer tray according to claim 1, wherein the bent portions (10) and slits (13) are formed over the entire length of the spring plate (9) in the height direction, and both side edges of the spring plate are fully insertable into the slits. A bobbin transfer tray according to claim 1 or 2, wherein the spring plate (9) is curved so that the curvature of its inner circumferential surface is equal at the top to that of the outer circumferencial surface (8) of the peg (2), and becomes progressively smaller in the downward direction. A bobbin transfer tray according to on of the claims 1 to 3, wherein the depth of the slits (13) from the outer circumferencial surface of the peg is greater than the length of the bent portions (10) of the spring plate (9).

Inventors: YOKOTA ITARU, YOKOTA, ITARU
Applicants: MURATA MACHINERY LTD, MURATA KIKAI KABUSHIKI KAISHA
Application year: 1999
Main classification: B65H67
IPC codes: B65H49, B65H67, D01H9