Patent Description:
Such a conveyor is known from <CIT>. The known conveyor is provided with a slat belt as an endless conveying member, which can transport products in vertical direction. In case of transporting weak, block-shaped products, these will be twisted somewhat during travelling through the helical conveying path. For transporting relatively long, wide and rigid, block-shaped products the conveyor will preferably be provided with a conveying path including a relatively large radius and/or a small inclination, since this type of products tends to rest on the slat belt through only two corners located opposite to each other in diagonal direction of the product; more specifically: the highest corner at the inner bend and the lowest corner at the outer bend of the helical conveying path. The inclination in the inner bend is steeper than the inclination in the outer bend. In practice a product will seek a third supporting location, such that it may wobble or even turn over. Another disadvantage is that at the corners of the product relatively high forces may locally act on the conveying member.

<CIT> is related to a conveyor which has a pliable endless belt adapted to negotiate a multiplicity of helical convolutions in a non-planar or twisted mode, and is also adapted to negotiate straight runs tangentially continuing with the helical rungs, with the belt in the straight runs operating in a flat planal untwisted mode. The belt is composed of a link-type chain having pins and rollers with tolerances among the component operating parts as to provide extension and contraction capabilities and of chain-connected separate and independent slats, supported by fixed helical track bars substantially at the mid-length of the slats, leaving the free ends of the slats free to flex toward conformity with flat-bottomed objects transported, whereby slack is introduced in each convolution to prevent snubbing or binding.

An object of the invention is to provide a conveyor which is able to transport rigid, block-shaped products in a stable manner.

This object is achieved with the conveyor according to the invention, which is defined in claim <NUM>.

It is noted that the word helical indicates that the conveying path in this portion of the conveyor is climbing continuously.

The invention will hereafter be elucidated further with reference to drawings showing an embodiment of the invention very schematically.

<FIG> shows a conveyor <NUM>. The conveyor <NUM> has a helical conveying path <NUM>, which runs about an upright central axis <NUM>. Furthermore, the conveyor <NUM> has a frame <NUM> which comprises a central column <NUM>, feet <NUM> and a helical guide trough <NUM>. The feet <NUM> and the guide trough <NUM> are mounted to the column <NUM>.

The conveyor <NUM> is provided with an endless conveying member, in this case a slat belt <NUM>, which is driven by a motor and is guided along the guide trough <NUM>. The slats of the slat belt <NUM> have a longitudinal direction in transverse direction of the conveying direction of the slat belt <NUM>. The slats are mutually connected through a chain, for example a side-bow chain. The slat belt <NUM> follows the helical conveying path <NUM> in vertical direction and is guided back through reverse rollers <NUM> and <NUM> at the ends of the helical conveying path <NUM> via a return section <NUM> by the shortest path to the helical conveying path <NUM>.

Each of the slats of the slat belt <NUM> is provided with a spherical projection <NUM> in its centreline, in this case at the centreline where the chain is located, as well. The upper sides of the projections <NUM> together form an upwardly directed supporting surface <NUM> for supporting a product. <FIG> show that the supporting surface <NUM> is located in a central portion of the conveying path <NUM>, as seen in a plane in which the central axis <NUM> lies, or a radial plane with respect to the central axis <NUM>. Products like piece goods G can be placed onto the conveying member <NUM> and can be supported and conveyed by the supporting surface <NUM>. The supporting surface <NUM> can also be formed in alternative manners, for example without using the slats.

<FIG> show cross-sections of the conveyor <NUM> according to <FIG> at a product G which is on the conveying path. The figures show that the width of the supporting surface <NUM> in radial direction of the central axis <NUM> is much smaller than the distance between the central axis <NUM> and the supporting surface <NUM>, for example smaller than <NUM>% thereof: moreover the conveying path <NUM> is free from obstacles at opposite sides of the supporting surface <NUM> at the height level of the supporting surface <NUM>.

If the supporting surface was formed by flat upper sides of the slats, a block-shaped product having a flat and rigid bottom would basically rest on the slat belt through only two diagonally opposite corners, more specifically the highest corner at the inner bend and the lowest corner at the outer bend of the helical conveying path <NUM>. This is caused by the fact that the inclination at the inner bend is steeper than the inclination at the outer bend. In practice a product will seek a third supporting location, such that it can wobble or even turn over.

The narrow supporting surface <NUM> being formed by the spherical projections <NUM> in the conveyor as shown in <FIG> is approached by a line contact between the bottom of the product G and the supporting surface <NUM> in case of a block-shaped product G having a flat and rigid bottom. Since in this case there is a space between neighbouring projections <NUM> of the slats in the conveying direction, there will be a broken line as seen from above, in fact a series of point contacts on a curved line. If the line contact or the series of point contacts would form a straight line, there would not be a stable supporting capacity, but since there is a line contact with a curved line, an automatic support of at least three points which are not on a single straight line, is created.

<FIG> shows that in the radial plane with respect to the central axis <NUM> the flat bottom of the product G in the middle of the product G extends nearly horizontally. In the conveying direction the product G is angled with respect to the horizontal plane which angle almost equals the average inclination of the conveying path <NUM>. The cross-sections in other radial planes, as shown in <FIG>, show that the bottom of the product G have deviating angles with respect to the frame <NUM> than in the cross-section according to <FIG>. It is noted, that if cross-sections are drawn of planes which extend parallel to that as shown in <FIG>, the orientation of the product G would be always the same in the drawings.

<FIG> make clear that if the slats in radial direction with respect to the central axis <NUM> at a distance from the supporting surface <NUM> would have an obstacle at the height level of the supporting surface <NUM>, these obstacles would form an extra contact surface outside the approached line contact and the intended effect would be destroyed. Thus, basically in <FIG> the slats on which the projections <NUM> are applied have no function and for that reason they are depicted as dashed lines.

<FIG>, <FIG> illustrate that the lack of obstacles at opposite sides of the supporting surface <NUM> means that a block-shaped product which is wider than the supporting surface <NUM> and even wider than the slat belt <NUM>, and having a length of <NUM>-<NUM>% of the length of a single revolution of the helical conveying path, for example, or is supported by for example <NUM>-<NUM> slats, the dimensions of the slat belt <NUM> are such that the block-shaped product only contacts the supporting surface <NUM> and not the remainder of the slats outside the supporting surface <NUM>.

Although the approximated curved line contacts can transport block-shaped products having a rigid bottom, in practice there will be a demand to avoid possible tilting of a product with respect to the line contact. This might occur, for example, in case of uneven weight distribution of the product G or placing the product G out of centre on the conveying path <NUM>. In order to prevent a product from turning over, an alternative conveyor is provided with bearing surfaces <NUM>, see <FIG>. In this conveyor the bearing surfaces <NUM> are formed by upper sides of small blocks which are provided on the slats. Hence, the bearing surfaces <NUM> move together with the supporting surface <NUM>. However, it is also conceivable that the bearing surfaces <NUM> have a fixed position on the frame <NUM>. When the product G tends to tilt, the bearing surfaces <NUM> will catch the product G.

In the conveyor according to <FIG> the bearing surfaces <NUM> are directed upwardly and are located below the supporting surface <NUM>, as seen in a plane which extends radially with respect to the central axis <NUM>. In another alternative conveyor the bearing surfaces <NUM> are located at the inner bend and outer bend of the conveying path <NUM>. This is shown in <FIG>, in which the slats are also made narrower in order to illustrate that they do not have a function in this case. The bearing surface at the inner bend of the conveying path <NUM> is indicated by <NUM> in the figures and is directed outwardly with respect to the central axis <NUM>. The bearing surface at the outer bend of the conveying path <NUM> is indicated by <NUM> in the figures and directed to the central axis <NUM>. The bearing surfaces <NUM>, <NUM> in this conveyor will specifically be applied for transporting relatively tall products. The bearing surfaces <NUM>, <NUM> are located above the supporting surface <NUM> in this case, as seen in a plane which extends radially with respect to the central axis <NUM>. Although the bearing surfaces <NUM>, <NUM> are part of the frame <NUM> in this conveyor, it is also conceivable to lengthen the slats and to provide their ends with upright supports having bearing surfaces <NUM>, <NUM> thereon.

<FIG> show an embodiment of a conveyor according to the invention. In this case the supporting surface is formed by slats each having a central portion <NUM> and two lateral portions <NUM>. The lateral portions <NUM> of the supporting surface are located in radial direction with respect to the central axis <NUM> at opposite sides remote from the central portion <NUM>. The lateral portions <NUM> are resiliently connected to the central portion <NUM> via the slats. In rest, as shown in <FIG> the lateral portions <NUM> may lie at a higher level than the central portion <NUM> as seen in a radial plane through the central axis <NUM>. This means that in case of a rebound the product may also be supported by one of the lateral portions <NUM>, as can be seen at the right side of <FIG> and the left side of <FIG>, for example.

Preferably, the lateral portions <NUM> may rebound in vertical direction with respect to the central portion <NUM> by more than <NUM>% of the pitch of the helical conveying path <NUM> as can be seen in a plane in which the central axis <NUM> lies.

The lateral portions may be all kinds of spring elements, such as gel-filled spring members.

<FIG> show still another conveyor. In this case the slats of the slat belt <NUM> are tiltable about the helical centreline of the slat belt <NUM>, such that a twistable supporting surface can be obtained. The helical centreline lies close to the chain in the centre of the conveying path in this conveyor. Each of the slats has a flat upper side. In the cross-sections as shown in <FIG> it can be seen that the slats take a position which corresponds to the bottom of the block-shaped product G. In such a case neighbouring slats have different orientations with respect to the horizontal. Due to the helical conveying path this means that the supporting surface is twisted locally.

<FIG> show still another conveyor. In this case each of the slats has a flat upper side and the slats are bendable in vertical direction in order to obtain a twistable supporting surface. The slats are only fixed to the chain at the helical centreline. In the cross-sections as shown in <FIG> show that the non-loaded parts of the slats do not rebound.

Claim 1:
A conveyor (<NUM>), comprising a helical conveying path (<NUM>) having an upright central axis (<NUM>), a frame (<NUM>) and an endless conveying member (<NUM>) in the form of a slat belt for transporting a product (G) through the conveying path (<NUM>) which conveying member (<NUM>) is displaceable with respect to the frame (<NUM>), wherein the conveying member (<NUM>) is provided with an upwardly directed supporting surface for supporting a product (G), wherein the supporting surface is formed by slats, wherein each of the slats is provided with a central portion (<NUM>) and lateral portions (<NUM>) which are located in radial direction with respect to the central axis (<NUM>) at opposite sides of the central portion (<NUM>), characterized in that the lateral portions (<NUM>) are resiliently connected to the central portion (<NUM>) via the slats, wherein in rest the lateral portions (<NUM>) may lie at a higher level than the central portion (<NUM>) as seen in a radial plane through the central axis (<NUM>) such that in case of a rebound the product (G) is also supported by one of the lateral portions (<NUM>), wherein the lateral portions (<NUM>) may rebound in vertical direction with respect to the central portion (<NUM>) by more than <NUM>% of the pitch of the helical conveying path (<NUM>) as can be seen in a plane in which the central axis (<NUM>) lies, wherein the lateral portions are spring elements, such as gel-filled spring members.