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(11) | EP 0 336 020 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Apparatus for sealing of bands |
| (57) The apparatus comprises a gripping member for releasably retaining one end portion,
14, of a band, 13, a band tensioning member for restricting the band, 13, around an
article and a seal crimping means comprising a stationary plate, 41, and a ram, 27,
movable relative to the plate, 41. The plate, 41, has a cavity having symmetrical contour along a centerline thereof, the contour providing opposite surfaces, 48 and 48a, upon which respective leading edges of extension portions, 30 and 31, of a band seal, 21, will contact at an angle not perpendicular, the leading edges will then slide on the surfaces, 48 and 48a, causing the extensions, 30 and 31, to bend inwardly toward the centerline of the seal, 21, when forcedly engaged by the movable ram, 27, until the extensions, 30 and 31, become essentially parallel to an upper portion of the seal, 21, with overlapping portions of the band, 13, therebetween. The cavity of the plate, 41, has a bottom surface, 49, and two lateral inclined surfaces, 48 and 48a, including an angle of about 60°. |
[0001] This invention relates to an apparatus for securing overlapping end portions of a band loop and in particular an apparatus in which the securing is done with a friction seal formed around a portion of the band.
[0002] There are many existing units, both stationary and portable, that are used to attach the ends of a band that has been placed around a package.
[0003] Such units first tighten the band and then make a sealed joint at the overlapping end portions of the band.
[0004] The two basic functions, tension of band and sealing, can be incorporated in a single apparatus or they can be performed by separate devices. The latter are usually in the form of portable tools.
[0005] Whether the tools are separate or as a combination device the functions are commonly known as:
1) Tensioner, or tensioning section, for tightening the loop of band around the article, and
2) Sealer, or sealing section, for securing the overlapping end portions of the band after the tensioning function is completed.
[0006] The tensioning has been done by methods including a ratchet bar, rotating toothed wheel, rotatable clamp as well as other less known systems both manual and power driven. The sealing has been performed by metallic and non metallic seals, that are crimped around the bands, slitting and interlocking the band end portions and, in the case of non metallic band, by heating the band portion for fusion welding.
[0007] The present invention provides an improvement in the apparatus for crimping a seal around a portion of the overlapping ends of a band and the shape of the seal used with such an apparatus.
[0008] Seals are normally prefolded in some manner to form a flat upper portion that is somewhat wider than the band with extending portion on either side that are folded tightly around the two end portions of the band.
[0009] To provide a surface to resist slipping, especially with non-metallic band, the under side of the seal that comes in contact with the band portions is treated or scored.
[0010] Although in some cases the force created on the band by the seal being tightly formed would be acceptable, addition of a frictional slip resistance surface to the seal is preferred.
[0011] The position of the extension portions of the seal vary accordingly to the type of the tool in which they are to be crimped.
[0012] The most common of which is having the extensions of equal length and preset at less than 90° from the plane of the upper portion.
[0013] This shape provides two important aspects regarding combination tools. Firstly the seals can be stacked in a manner that allows the end of the extended portions to overlap the portion near the bend. The overlapping method of stacking allows more seals to be placed in a given space within the tool. This space is provided by a means generally known as a seal magazine.
[0014] The seal magazine associated with portable tools needs to be kept to a minimum size due to space and balance limitations on such portable tools. This in turn means there will be a limited quantity of bands that can be placed around articles before the seal magazine will have to be replenished.
[0015] Secondly the band does not have to be exactly in alignment with the center of the seal, when advancing the band between the extended portions, or when positioning the seal over the ends of the band.
[0016] By presetting the extensions at 15° each seal will fully nest to provide the maximum seals in a given space.
[0018] By presetting the extensions at 90° the crimping can be accomplished easily but only a fraction of the quantity of seals can be loaded in the combination tool.
[0019] Most systems therefore use a means in which the seal extension portions are preset at approximately 60° from upper portion and the combination tool crimping means involve pivotal jaws.
[0020] An object of the present invention is to provide an improvement in the securing of the overlapping portions of a band placed about an article.
[0021] Another object of the invention is to provide an improvement in the crimping means of a band seal.
[0022] Another object of the invention is to provide the crimping means without the use of pivotal or rotating jaws.
[0023] And yet another object of the invention is to provide a band seal configuration that will function smoothly in such a crimping means.
[0024] The present invention provides a trouble free and less expensive means of crimping, and a seal with preset extension to function smoothly in such means.
[0025] The jaw used to fold the extension portions around the under side of the band is stationary within the portable tool. The surface of the jaw is shaped to allow the extension to contact a slope or radius on the jaw and then be forced inwardly due to a force applied to the upper portion of the seal. This force can be nothing more than a ram operated by a cam handle means. Having the extensions at 90° would of course require less force by the ram but this would defeat the stacking advantage. The simplicity of the jaw and ram is lost when the extensions are preset at less than 70°, therefore the present invention limits the seal configuration to having the extension portions of equal length, and each extension portion preset between 70° and 80° from the plane of the upper portion.
[0026] These and other features will become apparent according to the description and accompanying illustration in which:
FIGURE 1 is a side elevation view of an article with a band attached thereto by an apparatus containing a seal crimping means according to the present invention;
FIGURE 2 is a cross-sectional view of the seals stacked one above the other in a seal magazine along line A-A of FIGURE 1;
FIGURE 3 is a cross-sectional view of the relationship between the seal and jaw configuration along line B-B of FIGURE 1 when the crimping means is in an open position;
FIGURE 4 is the same view as FIGURE 3 except the crimping means partially closed;
FIGURE 5 is the same view as FIGURE 3 except the crimping means fully closed;
FIGURE 6 is a perspective view of a seal according to the present invention.
[0027] Referring first to FIGURE 1 one form of a combination strapping tool, 11, is shown resting to the top of a package, 12, that is to be held closed by a band, 13. One end, 14, of the band, 13, has been placed in the tool, 11, and retained by a gripping jaw, 15.
[0028] The band, 13, is made into a loop, 16, around the package, 12, and slipped into the tool, 11, to lay over the bottom plate, 17, and overlap the end portion, 14. The band, 13, is also inserted into a slot, 18, in the tensioning wheel, 19. A hand lever, 20, is operated in a ratchet like motion to rotate the wheel, 19, in a counter clockwise direction. The excess band, 13, would be wound around the wheel, 19, until the loop, 16, is drawn tightly about the package, 12.
[0029] The tool, 11, having completed the tensioning function will be shifted to a means for securing the overlapping portions of the band, 13, with a sealing element, 21, while at the same time continue to retain the tension in the loop, 16. The method of shifting to the securing means can be done by the operator manually or done automatically within the tool. There could also be a second lever for operating the securing means completely independent of the tensioning means. A seal magazine, 22, is mounted on the tool, 11, to locate the stack, 23, of seals, 21, above the overlapping portions of the band, 13. A transfer device, 24, is actuated to slide the leading seal, 25, in the lengthwise direction of the band, 13, from the seal stack, 23. The seal, 25, is slid into the seal crimping means, 26, underneath a ram portion, 27, of the crimping means, 26, and the next seal, 28, moves into position to be ready for the next loop. The crimping means, 26, will move the ram, 27, and seal, 25, downward over the overlapping portions of the band, 13, and clamp the seal, 25, tightly therearound as will be described later in detail.
[0030] The tool, 11, as described is but one of many embodiments placing and tensioning a band around a package. The power means could be motor driven or various assortment of toothed gears and air components. The scope of the present invention is within the means of clamping a seal around the overlapping portions of a band and not limited to the type or style of tool upon which it is used.
[0031] Accordingly, FIG. 2 and 6 show the seal stack, 23, within the seal magazine, 22, and the sealing element, 21. Element, 21, is made from a single piece of material and when shaped forms an upper portion, 29, and two downwardly extending portions, 30 and 31. The upper portion, 29, is limited in one direction, commonly known as "Seal Length", by two parallel edges, 32 and 32a.
[0032] The first extending portion, 30, is made by bending, in a clockwise direction as viewed in FIGURE 6, the material along a line, 33, perpendicular to edges, 32 and 32a. The other extending portion, 31, is made by bending the material in a counter clockwise direction along a line, 34, also perpendicular to edges, 32 and 32a, thus line, 34, is parallel to line, 33. The portions, 30 and 31 are also limited in one direction, the same as the upper portion, 29, by edges, 32 and 32a. The first portion, 30, is limited in the other direction by an edge, 35, parallel to line, 33, and portion, 31, is likewise limited by edge, 36, parallel to line, 34. Therefore all three portions, 29, 30 and 31, have a rectangular shape and portions, 30 and 31, are the same size and are bent downward between 70° and 80° from the upper portion, 29.
[0033] As seen in FIGURE 2 the seals, 21, can nest one over the other to allow considerable more seals in the magazine, 22, than if the portions, 30 and 31, were perpendicular to upper portion, 29.
[0034] The magazine, 22, has a front wall, 37, and a back wall, 38, to provide a cavity in which the seals, 21, are retained along the center line of the crimping means, 26. The bottom edge, 39, of the leading seal, 25, rests on a portion, 40, of a stationary plate defining a lower jaw, 41, and the opposite edge, 42, rest on a plate, 43, attached to the magazine wall, 37.
[0035] The plate, 43, has one edge, 44, bent upward and the jaw, 41, has a tapered edge, 45, to allow easy entry of the band, 13. The end, 14, that is held by the gripping jaw, 15, is supported by a surface, 46, to keep the band, 13, a distance above a cavity provided in the lower jaw, 41, and defining the crimping surface, 47, of the lower jaw, 41. After the loop, 16, has been placed around the package, 12, the band, 13, overlaps the end, 14, and is also positioned above surface, 47.
[0036] The transfer device, 24, pushes the leading seal, 25, from the magazine, 22, into the crimping means, 26, to align the centerline of the lower jaw, 41, and under the ram, 27, as shown in FIGURE 3.
[0037] As the ram, 27, moves toward the jaw, 41, the seal, 21, is also moved downward until the edges, 39 and 41, contact the crimping surface, 47. The surface, 47, has a symmetrical shape about the centerline of the jaw, 41.
[0038] The cavity of the jaw, 41, can best be described as having two inclined surfaces, 48 and 48a, having an included angle of no more than 60° and a straight horizontal lower surface, 49, intersecting surfaces, 48 and 48a.
[0039] At both intersections there is a radius, 50, to provide a smooth continuous surface, 47, upon which the seal edges, 39 and 42, will slide.
[0040] The upper edges, 51 and 51a are further apart than the outermost edges, 39 and 42, of the seal, 21, to assure the seal, 21, will be crimped when the ram, 27, is powered downward.
[0041] As the ram, 27, continues its downward power stroke, as shown in FIGURE 4, the force on the seal, 21, at the bend lines, 33 and 34, is transmitted along portions, 30 and 31, against inclined surfaces 48 and 48a.
[0042] Since the portion, 30, is positioned at an angle considerably off perpendicularity to inclined surface, 48, there is a force vector causing portion, 30, to bend inwardly toward the centerline of the seal as the edge, 42, slides along inclined surface, 48. The opposite seal portion, 31, likewise bends inwardly.
[0043] Since the overlapping portions of the band, 13, were supported above lower surface, 49, by top portion, 46, the edges 39 and 42, will slide under band portion, 14.
[0044] It is possible that the seal portions, 30 and 31 do not remain flat during the bending but tend to take on a temporary arcuate shape.
[0045] After the ram, 27, has completed the full power stroke, as shown in FIGURE 5, the seal, 21, is fully crimped around the overlapping band portions, 13 and 14, between the ram, 27 and jaw, 41.
[0046] The band portions are therefore squeezed between seal portion, 29, 30 and 31, to provide a frictional securing means. After the full crimp is made the free portion of the band, 13, is severed near the end of the seal, 21, by a cutting means, 52. The ram, 27, is raised and the gripping jaw, 15, is released to allow the tool, 11, to be moved to the next position. To provide a stronger frictional seal the inside surfaces of the seal can be coated or serrated which is of great value when using non metallic band.
1. An apparatus for securing a band around an article so that two overlapping portions
of said band are held together, said apparatus comprising in combination a gripping
means for releasably retaining one end portion of said band, a band tensioning means
for restricting said band around said article, a seal crimping means movable between
an open and closed position, a magazine adapted to retain a series of band seals,
a means for transferring said seals one at a time from said series to a position within
said crimping means, a power means for operating said gripping, crimping, tensioning
and transferring means, said crimping means further comprising a stationary plate,
a movable ram spaced away from said plate providing said open position, a means to
forcedly move said ram toward said plate to provide said closed position characterized
in that said plate has a cavity having symmetrical contour along a centerline thereof,
said contour providing a surface upon which a leading edge of an extension portion
of said seal will contact at an angle not perpendicular, said leading edge will slide
on said surface causing said extension to bend inwardly toward the centerline of said
seal when forcedly engaged by said ram, said extensions being essentially parallel
to an upper portion of said seal with said overlapping portions of said band therebetween
whenever said crimping means is in said closed position.
2. An apparatus as claimed in claim 1, wherein said cavity has a bottom surface and
two lateral inclined surfaces, said inclined surfaces including an angle of about
60°.
3. A sealing element for securing overlapping portions of a band for use in an apparatus
as defined in claim 1 or 2 comprising a first, second and third portion, all said
portions having a flat rectangular shape, said first and second portions having a
first common side, said first and third portions having a second common side, said
first and second common sides being parallel, said second and third portions being
rotated in opposite direction about corresponding said common sides at an angle between
70° and 80° from that of said first portion, said first, second and third portion
being integral.
4. A sealing element as defined in claim 3 in which said second and third rectangular
portions are equal in size.