Accumulating Conveyor

Abstract

The accumulating conveyor (1) includes a first spiral track (6) and a second spiral track (7) with coincident centerlines, a first S-shaped bridge (8) and a second S-shaped bridge (9), each having a first curved portion (8a) in one direction and a second curved portion (8b) in the opposite direction when viewed from above, a first set of auxiliary guides (16) and a second set of auxiliary guides (17), and an endless conveyor belt (10) drivable in a conveying direction (X). The conveyor belt (10) can be guided by a set of first and second spiral tracks (6, 7), bridges (8, 9), and auxiliary guides (16, 17), so that under operating conditions, the conveyor belt (10) can move upwards on the first spiral track (6) from its lower end (18) to a location below its upper end (15), on the first bridge (8) to a location below its upper end (19), on the second spiral track (7), and The second spiral track (7) is followed successively downward to its lower end (20), the first set of auxiliary guides (16) to the upper end (19) of the second spiral track (7), the second spiral track (7) downward, the second bridge (9) to the first spiral track (6), the first spiral track (6) upward to its upper end (15), and the second set of auxiliary guides (17) to the lower end (18) of the first spiral track (6). The bridges (8, 9) are at least partially located on the common inside of the first and second spiral tracks (6, 7) and are simultaneously movable along the first and second spiral tracks (6, 7) to vary the effective length of the conveyor belt (10) between the lower ends (18, 20) of the first and second spiral tracks (6, 7) via the first bridge (8) on the one hand, and between the upper ends (15, 19) of the first and second spiral tracks (6, 7) via the second bridge (9) on the other hand. At least a portion of the first and second curved portions (8a, 8b) of at least one of the first and second bridges (8, 9) are inclined inwardly therefrom.

Description

[Technical field]

[0001] The present invention relates to an accumulating conveyor, comprising a first helical track and a second helical track with coincident centerlines, a first S-shaped bridge and a second S-shaped bridge, each having a first bend in one direction and a second bend in the opposite direction when viewed from above, a first set of auxiliary guides and a second set of auxiliary guides, and an endless conveyor belt drivable in a conveying direction, wherein the conveyor belt is guideable by the first and second helical tracks, the bridges and the set of auxiliary guides, so that under operating conditions the conveyor belt travels upwards on the first helical track from its lower end to a location below its upper end, through the first bridge, through its upper bridge in the second helical track, and through the first bridge, through its upper bridge in the second helical track. the second spiral track to a location below the end, then following the second spiral track downward to its lower end, the first set of auxiliary guides to an upper end of the second spiral track, then following the second bridge to the first spiral track, then following the first spiral track upward to its upper end and the second set of auxiliary guides to the lower end of the first spiral track, the bridge being at least partially located within a common interior of the first and second spiral tracks and movable simultaneously along the first and second spiral tracks to vary the effective length of the conveyor belt between the lower ends of the first and second spiral tracks via the first bridge on the one hand and between the upper ends of the first and second spiral tracks via the second bridge on the other hand. [Background technology]

[0002] Such an accumulating conveyor is known from DE 10 200 43 536 A1. The known accumulating conveyor is used to transport a mass flow of rod-shaped articles from a first station at the lower end of a first helical conveyor to a distant second station at the lower end of a second helical conveyor via a first bridge. Since the effective length of the conveyor belt between the lower ends of the first and second helical tracks can vary, the conveyor can be applied as a first-in, first-out reservoir of variable capacity. At the bridge inlet of the respective bridge, the conveyor belt is lifted off the helical track, and at the bridge outlet of the respective bridge, the conveyor belt is lowered onto the helical track. Furthermore, the first and second bends of the bridge are sharper than the bends of the first and second helical tracks. To prevent the products from tipping on the conveyor belt due to centrifugal forces while traveling along the first bridge, the maximum speed of the conveyor belt of known accumulating conveyors is limited. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] U.S. Patent No. 5,413,213 Summary of the Invention [Problem to be solved by the invention]

[0004] SUMMARY OF THE PRESENT EMBODIMENT It is an object of the present invention to provide an accumulating conveyor in which the conveyor belt can be operated at relatively high speeds. [Means for solving the problem]

[0005] This object is achieved with an accumulating conveyor according to the invention, in which at least a portion of the first and second curved portions of at least one of the first and second bridges are inclined towards their insides. Due to this feature, the accumulating conveyor according to the invention allows relatively high conveying speeds with minimal risk of tipping the products transported by the conveyor belt.

[0006] The first and second sets of auxiliary guides may include non-helical tracks, e.g., straight or curved tracks, and / or rollers, sprockets, etc., for guiding the conveyor belt outside the first and second helical tracks.

[0007] The conveyor belt may include a drivable flexible conveyor line and slats mounted on the conveyor line. The conveyor line may be a sidebow chain. Each slat may include two guide rollers spaced apart from each other in a transverse direction of the conveyor belt, where the guide rollers roll along cooperating rails.

[0008] The first and second bridges may be fixed to each other, so that the first and second bridges are displaced simultaneously when driving only one of the bridges. Driving only one of the bridges may be performed by the conveyor belt by creating a traction difference in the conveyor belt upstream and downstream of one of the first and second bridges. The first and second bridges may be connected to each other in a flexible manner, so that they are movable relative to each other in a direction along the first and second helical tracks, for example by springs, to maintain tension in the conveyor belt. This feature may also be applied to accumulating conveyors that do not have inclined first and second bends in the first and / or second bridges.

[0009] The accumulating conveyor may include motors for driving the conveyor belt. For example, a first motor may be located at or adjacent to a lower end of the first spiral track, and a second motor may be located at or adjacent to a lower end of the second spiral track. When both motors are operated at the same speed, the first and second bridges are stationary relative to the first and second spiral tracks, and the effective length of the conveyor belt between the lower ends of the first and second spiral tracks through the first bridge remains the same, and the effective length of the conveyor belt between the upper ends of the first and second spiral tracks through the second bridge remains the same. When only the first motor is operated, the conveyor belt does not move at the lower end of the second spiral track, and the first motor pulls the first and second bridges upwards by the conveyor belt, thus increasing the effective length of the conveyor belt between the lower ends of the first and second spiral tracks via the first bridge. In this case, products can be supplied to the accumulating conveyor at the lower end of the first spiral track to temporarily store them, but no products leave the accumulating conveyor at the lower end of the second spiral track. Similarly, the effective length of the conveyor belt between the upper ends of the first and second spiral tracks via the second bridge is reduced. When products are stored between the upper ends of the first and second spiral tracks via the second bridge, products can leave the upper end of the first spiral track, but no products can be supplied to the upper end of the second spiral track.

[0010] When only the second motor is operated, the conveyor belt does not move at the lower end of the first spiral track, and the second motor pulls the first and second bridges downwards by the conveyor belt, thus reducing the effective length of the conveyor belt between the lower ends of the first and second spiral tracks via the first bridge. In this case, no products can be fed to the accumulating conveyor at the lower end of the first spiral track, but stored products can leave the accumulating conveyor at the lower end of the second spiral track. Similarly, the effective length of the conveyor belt between the upper ends of the first and second spiral tracks via the second bridge increases. Products can be fed to the upper end of the second spiral track, but no products leave the upper end of the first spiral track.

[0011] In a specific embodiment, the first and second spiral tracks surround each other, so that they extend radially adjacent to each other relative to their centerlines. In an alternative embodiment, the first and second spiral tracks extend parallel to each other and lie on top of each other, so that they lie on a common imaginary cylinder and together follow a common spiral path. In the latter case, the first and second spiral tracks nest within each other.

[0012] In a particular embodiment, at least one of the first and second bridges has a first curved section, which has a less steep longitudinal gradient in the conveying direction and a smaller radius when viewed from above compared to the second curved section. When the product is transported across the first or second bridge, centrifugal forces act on the product at the first and second curved sections. The reduction in steepness of the longitudinal gradient in the conveying direction appears to allow higher centrifugal forces, especially for products with a rounded bottom. The first curved section has a less steep longitudinal gradient, which allows a relatively high conveying speed, thereby providing the opportunity to apply a relatively small radius. On the other hand, the second curved section, which has a steeper longitudinal gradient, does not allow a relatively high conveying speed, but due to its relatively large radius, a relatively high conveying speed can be achieved.

[0013] When the first and second spiral tracks surround each other, such that the first and second spiral tracks extend radially adjacent each other relative to their centerlines, the first curved section can extend at least partially over adjacent portions of the first and second spiral tracks. For example, when the first spiral track surrounds the second spiral track, the first bridge lifts the conveyor belt off the first spiral track and guides it over adjacent portions of the first and second spiral tracks, toward the inside of the second spiral track, and from there, further toward the second spiral track.

[0014] In order to avoid height losses between, on the one hand, the conveyor belt in the adjacent section where the first bridge lies above the first and second helical tracks, and, on the other hand, the adjacent windings of the first and second helical tracks above that location of the first bridge, the longitudinal gradient in the conveying direction is preferably small at that location, which allows a relatively small radius and for that reason the first curve section is located there.

[0015] In a more specific embodiment, the first curve of at least one of the first and second bridges includes a first curved section and a second curved section, with at least a portion of the second curved section having a radius that is the same as the radius of the second curved section, where approximately less than one-quarter of the length of at least one of the first and second bridges may have a minimum first radius, while more than three-quarters of the length may have a minimum second radius that is greater than the minimum first radius.

[0016] The second curved portion can be located downstream of the first curved portion, meaning that the first spiral track surrounds the second spiral track such that the first curved section is located above adjacent portions of the first and second spiral tracks.

[0017] The angle of inclination may vary along the first and / or second bridge, preferably gradually increasing. The first and second spiral tracks may also be inclined inwards.

[0018] Because the radii of the first and second spiral tracks are greater than any curved sections within the first and second bridges, the maximum inclination angle of the first curved section is preferably greater than the inclination angles of the first and second spiral tracks.

[0019] In an advantageous embodiment, the conveyor comprises a link between the respective portions of the conveyor belt in the first and second bridges to transmit the drive force between the respective portions of the conveyor belt in the respective first and second bridges. Such a link can be, for example, a sprocket engaging the chain of the conveyor belt. In particular, when the bridges are located at a relatively high or low level in the accumulating conveyor, there may be a large difference in the number of turns along which the conveyor belt travels below the first bridge and above the second bridge, so that the actual traction force of the conveyor belt in each bridge may vary significantly when the conveyor belt is pulled at a location downstream of the first bridge and / or downstream of the second bridge. The link serves to drive the portion of the conveyor belt in one of the bridges, where the actual traction force is relatively high, by the portion of the conveyor belt in the other bridge, where the traction force is relatively low if the link is not applied.

[0020] At least one of the first and second bridges may be radially supported by at least one of the first and second helical tracks through bridge rollers provided on at least one of the first and second bridges, where the bridge rollers ride on at least one of the first and second helical tracks. The bridge rollers minimize friction between the cooperating bridges and the helical tracks, but a separate support track for guiding the bridge rollers need not be applied. If the conveyor belt includes slats with guide rollers, the bridge rollers of at least one of the first and second bridges may roll on the same surface of at least one of the first and second helical tracks as the guide rollers.

[0021] Preferably, the bridge rollers are located at at least one of the bridge inlet and the bridge outlet of at least one of the first and second bridges because the radial forces between the cooperating bridges and the helical track at the ends of the bridges when driving the conveyor belt are relatively high.

[0022] In a specific embodiment, the first and second spiral tracks each include an inner rail and an outer rail for guiding the conveyor belt, where the inner and outer rails are supported by a spiral plate. The spiral plate appears to form a rigid support even in the case of a relatively thin plate. The advantage of applying the spiral plate is the small height required compared to conventional support arms that extend radially to the centerline of the spiral track at different heights and at different angles around the centerline.

[0023] In another specific embodiment, the first and second bridges are at least connected to each other through an elongated curved connecting element that extends along at least one of the first and second helical tracks between the first and second bridges, and / or two separate portions of at least one of the first and second bridges are fixed to another elongated curved connecting element that extends along one of the first and second helical tracks between the two separate portions, in which case the space in the first and second helical tracks near the first and second bridges is used to place the connecting element or another connecting element.

[0024] At least one of the elongated curved connecting element and the further elongated curved connecting element may be flexible and guided by a corresponding one of the first and second helical tracks. This is advantageous, since the first and / or the second helical track is used not only for guiding the conveyor belt, but also for guiding the connecting element between the first and second bridges and between the respective remote portions of the first and second bridges. The flexible connecting element may include a chain.

[0025] In one specific embodiment, the first and second spiral tracks each comprise an inner rail and an outer rail surrounding the inner rail, wherein the conveyor belt is upwardly, downwardly and radially supported by the inner rail and upwardly supported by the outer rail and is upwardly movable relative to the outer rail, the accumulating conveyor comprises a protective carriage that is freely movable along at least one of the first and second spiral tracks between its upper end and a stop element spaced from the upper end, the protective carriage including a retaining member located above the conveyor belt on the protective carriage to minimize lifting of the conveyor belt from the outer rail, and the second bridge and protective carriage comprise cooperating engagement elements adapted to enable the second bridge to push the protective carriage upwardly along at least one of the first and second spiral tracks. The conveyor belt is not pushed downwards by the outer rail, so as to provide the possibility of lifting the conveyor belt off the spiral track, for example by moving it in an outward direction, so that it is still supported upwards by the outer rail, but is no longer hindered upwards by the inner rail. However, this may result in a risk of the conveyor belt tipping around the inner rail, for example in case of excessive traction on the conveyor belt. The distance between the upper end of at least one of the first and second spiral tracks and the stop element may be, for example, half a turn of the corresponding spiral track. In case of a derailment of the conveyor belt on the upper side of the accumulating conveyor between the upper end of the corresponding spiral track and the protective carriage with the highest level of traction, the derailment is stopped at the protective carriage located half a turn from the upper end. If a longer effective length of conveyor belt between the lower ends of the first and second spiral tracks via the first bridge is required, the second bridge can move the protective carriage upwardly and forward away from the stop element.

[0026] In another specific embodiment, each of the spiral tracks comprises an inner rail and an outer rail surrounding the inner rail, where the conveyor belt comprises slats mounted on a flexible conveyor line such as a sidebow chain, each of the slats comprises two guide rollers spaced apart from each other in a transverse direction of the conveyor belt, each guide roller having an axis of rotation with a vertical component, one of the guide rollers of each slat being supported upwardly, downwardly and radially by the inner rail, a portion of each slat being supported upwardly by the outer rail and movable upwardly relative to the outer rail, and an upper contact location between each of the guide rollers and the inner rail on which it is radially supported is located above a line along which the resultant radial force of the conveyor line towards the centerline of the first and second spiral tracks acts on that slat, meaning that the tendency to tilt is minimized.

[0027] In another specific embodiment, the conveyor belt includes slats mounted on a flexible conveyor line, such as a sidebow chain, where each slat includes two guide rollers spaced apart from each other in a transverse direction of the conveyor belt, each guide roller having an axis of rotation that includes a vertical component, and each of the first and second bridges includes inner and outer guides for guiding the respective guide rollers, each of the inner and outer guides having a trough shape including a lower sidewall, an upper sidewall, and a bottom between the lower and upper sidewalls, the lower and upper sidewalls diverging when viewed from the bottom, and at least one of the lower and upper sidewalls having a diverging angle with respect to the bottom that is less than 100°. This is a relatively small angle and prevents undesirable additional tilting of the conveyor belt when the conveyor belt moves in its transverse direction relative to the inner and outer guides. Such movement may occur during periods of low traction of the conveyor belt at some locations along at least one of the first and second bridges.

[0028] The invention will be explained below with reference to highly schematic drawings which show, by way of example, embodiments of the invention. [Brief description of the drawings]

[0029] [Figure 1] FIG. 1 is a perspective view of one embodiment of an accumulating conveyor according to the present invention. [Diagram 2] FIG. 2 is a cross-sectional view of the embodiment as shown in FIG. 1, viewed from above. [Diagram 3] 1, but showing a portion of the embodiment on a larger scale. [Figure 4] FIG. 2 is a perspective view of a section of a portion of the embodiment of FIG. 1. [Diagram 5] 5 is a view similar to FIG. 4, but showing the section at a different location. [Figure 6] FIG. 5 is a plan view of a portion of FIG. 4 on a larger scale. [Figure 7] FIG. 13 is an exemplary plan view of a lower bridge. [Figure 8] FIG. 1 is a side view of an embodiment of a conveyor belt including two slats. [Figure 9] FIG. 9 is a cross-sectional view of the conveyor belt as shown in FIG. [Figure 10] 10 is a view similar to FIG. 9, but with the conveyor belt supported by a spiral track. [Figure 11] 11 is a view similar to FIG. 10, but showing a portion of an alternative embodiment on a larger scale. [Figure 12] FIG. 2 is a cross-sectional view of the conveyor belt in one of the bridges. [Figure 13] FIG. 13 is a view similar to FIG. 12 but showing a different state. [Figure 14] FIG. 2 is a view similar to FIG. 1, but showing a portion of it on a larger scale. [Figure 15] FIG. 15 is a cross-sectional view of a portion as shown in FIG. [Figure 16] FIG. 2 is a view similar to FIG. 1, but showing a portion of it on a larger scale. [Figure 17]FIG. 17 is a cross-sectional view of a portion as shown in FIG. [Figure 18] FIG. 2 is a view similar to FIG. 1 of an alternative embodiment. [Figure 19] 19 is a view similar to FIG. 18, showing another variation. [Figure 20] FIG. 2 is a perspective view of an embodiment of an accumulating conveyor including a spiral support plate. [Figure 21] FIG. 21 is a cross-sectional view of the embodiment as shown in FIG. 20. [Figure 22] FIG. 13 is an exemplary diagram of an alternative embodiment of an accumulating conveyor according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] Figures 1 and 2 show an embodiment of an accumulating conveyor 1 according to the invention. The accumulating conveyor 1 has a frame 2 with legs 3 that rest on the floor. The accumulating conveyor 1 has a product inlet 4, where the products are received from a supply (not shown), e.g. a supply machine, and a product outlet 5, where the products are discharged, e.g. to a receiving machine (not shown). The accumulating conveyor 1 is suitable for temporarily storing the products between the product inlet 4 and the product outlet 5. For example, if the supply continues to supply products to the product inlet 4, whereas the receiving machine downstream of the product outlet 5 is temporarily out of order, the products can be stored. This can prevent the production line from coming to a complete halt.

[0031] The frame 2 supports a first spiral track in the form of an outer spiral track 6 and a second spiral track in the form of an inner spiral track 7. The outer spiral track 6 surrounds the inner spiral track 7. The inner spiral track 7 and the outer spiral track 6 are arranged concentrically with respect to each other. In other words, their centerlines coincide. The accumulating conveyor 1 further comprises a first S-shaped bridge in the form of a lower S-shaped bridge 8 and a second S-shaped bridge in the form of an upper S-shaped bridge 9 located above the lower bridge 8. The upper bridge 9 and the lower bridge 8 are connected to each other and are movable simultaneously along the inner spiral track 7 and the outer spiral track 6.

[0032] The accumulating conveyor 1 has a single endless conveyor belt 10, in this case a slat belt, including slats 11, mounted on a horizontally and vertically flexible chain 12, e.g. a sidebow chain. The chain 12 is driven by two electric motors 13, 14, one of which is located at the product inlet 4 and the other at the product outlet 5. However, other locations are also conceivable. The conveyor belt 10 is guided by an inner spiral track 7 and an outer spiral track 6, an upper bridge 9 and a lower bridge 8, a first set of auxiliary guides in the form of a first series of wheels or sprockets 16 and a non-spiral track, and a second set of auxiliary guides in the form of a second series of wheels or sprockets 17 and a non-spiral track.

[0033] Under operating conditions, the conveyor belt 10 travels in the conveying direction X from the product inlet 4 via a horizontal track to the lower end 18 of the outer spiral track 6, then travels upward along the outer spiral track 6 and reaches the lower bridge 8. The conveyor belt 10 then travels via the lower bridge 8 to the inner spiral track 7 to a location below the upper end 19 of the spiral track 7, then travels downward along the inner spiral track 7. At the lower end 20 of the inner spiral track 7, the conveyor belt 10 leaves the inner spiral track 7 and travels via a horizontal track to the sprocket 16 at the product outlet 5 of the accumulating conveyor 1. The path of the conveyor belt 10 between the product inlet 4 and the product outlet 5 forms an accumulation area that supports and transports the products. The length of the accumulation area can be varied by displacing the upper bridge 9 and the lower bridge 8 along the inner spiral track 7 and the outer spiral track 6.

[0034] Outside the accumulation area, the conveyor belt 10 has a free area between the product outlet 5 and the product inlet 4. The free area does not support and transport the product, but returns the conveyor belt 10 from the product outlet 5 to the product inlet 4 via the upper bridge 9. Its length varies inversely with the length of the accumulation area. From the sprocket 16 at the product outlet 5, the conveyor belt 10 moves upside down along a horizontal track to a sprocket 16 below the inner spiral track 7 and the outer spiral track 6, which leads the conveyor belt 10 upwards outside the outer spiral track 6, while a sprocket 16 at the upper end 19 of the inner spiral track 7 leads the conveyor belt 10 to the inner spiral track 7. The conveyor belt 10 then moves downwards along the inner spiral track 7 until it reaches the upper bridge 9. The upper bridge 9 guides the conveyor belt 10 into the outer spiral track 6 which guides the conveyor belt 10 upwards to a sprocket 17 at the upper end 15 of the outer spiral track 6 which directs the conveyor belt 10 downwards on the outside of the outer spiral track 6. The sprocket 17 on the underside of the outer spiral track 6 turns the conveyor belt 10 into a horizontal track towards the sprocket 17 at the product inlet 4.

[0035] The lower bridge 8 and the upper bridge 9 are indirectly displaced along the inner spiral track 7 and the outer spiral track 6 by both motors 13, 14. If the motors 13, 14 are operated at the same speed, the lower bridge 8 and the upper bridge 9 are stationary relative to the inner spiral track 7 and the outer spiral track 6. The accumulation area of ​​the conveyor belt 10 remains the same. If only the motor 14 at the product inlet 4 is operated, the conveyor belt 10 does not move at the product outlet 5, and the motor 14 at the product inlet 4 pulls the lower bridge 8 and the upper bridge 9 upwards by the conveyor belt 10. As a result, the accumulation area increases. If only the motor 13 at the product outlet 5 is operated, the conveyor belt 10 does not move at the product inlet 4, and the motor 13 at the product outlet 5 pulls the lower bridge 8 and the upper bridge 9 downwards by the conveyor belt 10. As a result, the accumulation area decreases.

[0036] The transition regions between the lower bridge 8 and the inner helical track 7 at the bridge exit 32 are similar to the transition regions between the outer helical track 6 and the lower bridge 8 at the bridge entrance 31, but in the reverse order, see Figure 3. Similarly, the transition regions between the upper bridge 9 and the respective inner helical track 7 and outer helical track 6 are similar.

[0037] Figures 3 to 6 show the accumulating conveyor 1 in more detail on the upper bridge 9 and on the lower bridge 8. Figures 4 and 5 show that the inner spiral track 7 and the outer spiral track 6 are similar. They have inner rails 6a, 7a and outer rails 6b, 7b, respectively. Figure 4 shows several slats 11 of the conveyor belt 10 on the outer spiral track 6. For illustrative reasons, parts of the slats 11 are not shown. For the same reason, the upper side of the slats 11 is not shown in Figure 6. Each slat 11 is equipped with two guide rollers 20, on either side of the chain 12, at a distance from each other in the transverse direction of the conveyor belt 10. The guide rollers 20 have an axis of rotation with a vertical component, in this case the guide rollers 20 are cylindrical. In the inner spiral track 7 and the outer spiral track 6, one of the guide rollers 20 of each slat 11 is supported by the inner rails 6a, 7a in the radial direction, upwards and downwards with respect to the center line of the inner spiral track 7 and the outer spiral track 6. For this reason, the inner rails 6a, 7a have a trough shape. The outer rails 6b, 7b support the slats 11 upwards only through their sliding bottom surfaces, which under operating conditions slide on the upper surfaces of the outer rails 6b, 7b. The sliding bottom surfaces are the undersides of the respective legs of the slats 11, on which the guide rollers are rotatably mounted. Due to the height difference between the guide rollers 20 and the sliding bottom surfaces of the slats 11, the outer rails 6b, 7b are located lower than the respective inner rails 6a, 7a of the inner spiral track 7 and the outer spiral track 6, as can be seen in the cross-sectional view. See FIG. 5. It is noted that which of the two guide rollers 20 of each slat 11 is active depends on the actual location of the slat 11 inside the accumulating conveyor 1. The guide rollers 20, which roll along the inner rail 6a of the outer spiral track 6, are spaced apart from the inner rail 7a of the inner spiral track 7.

[0038] 4-6 show in more detail the transition area between the outer spiral track 6 and the lower bridge 8 at the bridge entry 31. The lower bridge 8 is equipped with a diverter 21, which guides the slats 11 in the outward direction by guiding one of the guide rollers 20 through a trough profile that is similar to the trough profile in the inner rails 6a, 7a. During a first stage of diverting the slats 11, they are supported upwards, on the one hand, by the trough profile of the diverter 21 and, on the other hand, by the outer rail 6b, along which the slats 11 slide in the outward direction. In the next stage of diverting the slats 11, the guide roller 20 in the outer rail 6b is received by the outer guide 22 of the lower bridge 8, while the other guide roller 20 is received by the inner guide 23 of the lower bridge 8. The slats 11 then follow a path defined by the inner guide 23 and the outer guide 22 of the lower bridge 8. Both the inner guide 23 and the outer guide 22 are trough-shaped. The lower bridge 8 has a bottom plate 24 to which the inner guide 23 and outer guide 22 are mounted and which has a cutout 25 to provide space for the outer rail 6b.

[0039] It will be clear to one skilled in the art that the inner guide 23 in one bend of the S-shape of the lower bridge 8 actually forms the outer guide 22 in the opposite bend, and that the outer guide 22 in one bend actually forms the inner guide 23 in the opposite bend.

[0040] 3-5 show that the lower bridge 8 is supported and guided upwardly by the outer spiral track 6 at least through wheels 26 that roll on the upper surface of the inner rail 6a. The lower bridge 8 is also supported radially outward relative to the centerline of the outer spiral track 6 through bridge rollers 27 that roll along the inner rail 6a of the outer spiral track 6. FIGS. 5 and 6 show that the bridge rollers 27 are provided in the diverter 21 and roll along the inner rail 6a of the outer spiral track 6 on the same surface as the guide rollers 20 of the slats 11 of the conveyor belt 10.

[0041] The application of the wheels 26 and the bridge rollers 27 is not limited to the lower bridge 8, but can also be applied in the upper bridge 9. The application of the bridge rollers 27 is not necessarily related to other aspects as described in this application. In other words, the present invention also relates to the following aspects:

[0042] Aspect 1: An accumulating conveyor, comprising: a first helical track and a second helical track with coincident centerlines; a first S-shaped bridge and a second S-shaped bridge, each having a first curved portion in one direction and a second curved portion in the opposite direction when viewed from above; a first set of auxiliary guides and a second set of auxiliary guides; and an endless conveyor belt drivable in a conveying direction, the conveyor belt being connected to the first and second helical tracks, the bridges, and the auxiliary guides. The conveyor belt is guideable by a set of guides so that under operating conditions the conveyor belt can move upwardly on the first spiral track from its lower end to a location below its upper end, over the first bridge to a location below its upper end on the second spiral track, downwardly on the second spiral track to its lower end, over the first set of auxiliary guides to the upper end of the second spiral track, downwardly on the second spiral track, over the second bridge to the first spiral track, and over the first spiral track to the upper end of the second spiral track. a bridge located at least partially within a common interior of the first and second spiral tracks and movable simultaneously along the first and second spiral tracks to vary an effective length of the conveyor belt between the lower ends of the first and second spiral tracks via the first bridge on the one hand and between the upper ends of the first and second spiral tracks via the second bridge on the other hand, and at least one of the first and second bridges having an axis of rotation that includes at least a vertical component and being supported by at least one of the first and second spiral tracks in a radial direction with respect to a center line of the first and second spiral tracks through bridge rollers provided on said at least one of the first and second bridges, the bridge rollers resting on said at least one of the first and second spiral tracks. Thus, at least one of the first and second spiral tracks guides both the conveyor belt and the bridge roller.

[0043] Aspect 2: The accumulating conveyor of aspect 1, wherein the bridge roller is located at at least one of the bridge inlet and the bridge outlet of said at least one of the first and second bridges. This is advantageous because the radial force of the bridge against the corresponding helical track is relatively high due to traction forces in the conveyor belt.

[0044] Fig. 3 shows that the lower bridge 8 and the upper bridge 9 are connected to each other through a chain 28 along the inner spiral track 7 and the outer spiral track 6. Furthermore, two separate parts of the lower bridge 8 are fixed to a chain 29 that is movable along the inner spiral track 7, while two separate parts of the upper bridge 9 are fixed to a chain 30 that is also located on and movable along the inner spiral track 7. In Fig. 3, the chains 28, 29, 30 are simply pieces of the same material as the conveyor belt 10, and are guided by guide rollers 20 of the slats 11 along the inner spiral track 7 and the outer spiral track 6, although alternative chains and guides are contemplated.

[0045] The application of the chains 28-30 does not necessarily relate to other aspects as described in this application. In other words, the present invention also relates to the following aspects:

[0046] Aspect 1: An accumulating conveyor, comprising: a first helical track and a second helical track with coincident centerlines; a first S-shaped bridge and a second S-shaped bridge, each having a first curved portion in one direction and a second curved portion in the opposite direction when viewed from above; a first set of auxiliary guides and a second set of auxiliary guides; and an endless conveyor belt drivable in a conveying direction, the conveyor belt being connected to the first and second helical tracks, the bridges, and the auxiliary guides. The conveyor belt is guided by a set of auxiliary guides so that under operating conditions, the conveyor belt can move upwardly from its lower end to a location below its upper end, over the first bridge to a location below its upper end on the second spiral track, downwardly over the second spiral track to its lower end, over the first set of auxiliary guides to the upper end of the second spiral track, downwardly over the second bridge to the first spiral track, and over the first spiral track. the first helical track follows the second helical track upwardly to its upper end and the second set of auxiliary guides continuously to the lower end of the first helical track, the bridge being at least partially located on a common interior side of the first and second helical tracks and simultaneously movable along the first and second helical tracks to vary an effective length of the conveyor belt between the lower ends of the first and second helical tracks via the first bridge on the one hand and between the upper ends of the first and second helical tracks via the second bridge on the other hand, the first and second bridges being connected to each other at least through an elongated curved connecting element extending along at least one of the first and second helical tracks between the first and second bridges and / or two spaced apart portions of at least one of the first and second bridges being fixed to another elongated curved connecting element extending along one of the first and second helical tracks between said spaced apart portions.

[0047] Aspect 2: An accumulating conveyor as described in aspect 1, wherein at least one of the elongated curved connecting element and the another elongated curved connecting element is flexible in its transverse direction, e.g. a chain, and is guided by a corresponding one of the first and second spiral tracks.

[0048] Aspect 3: An accumulating conveyor as described in aspect 1 or 2, wherein the first and second bridges are connected to each other through two elongated curved connecting elements extending along the inner and outer spiral tracks, respectively.

[0049] FIG. 7 shows the bridge path that the conveyor belt 10 follows from the outer spiral track 6 to the inner spiral track 7 via the lower bridge 8 when viewed from above. The lower bridge 8 has an S-shaped bridge path with a first bend 8a in one direction or clockwise direction and a second bend 8b in the opposite or counterclockwise direction when viewed from above. The second bend 8b is located downstream of the first bend 8a in this embodiment. From the bridge inlet 31 to the bridge outlet 32, the bridge path can be successively subdivided into a lift section 33, a crossover section 34, a drop section 35 and a connecting section 36. Inside the lift section 33, the conveyor belt 10 is lifted from the outer spiral track 6 as previously described herein. The bridge path has a longitudinal gradient angle in the conveying direction X in the lift section 33, which angle is greater than the longitudinal gradient angle of the outer spiral track 6 in the conveying direction X. On the other hand, the longitudinal gradient angle within the lift portion 33 is relatively small, for example the angle of the outer spiral track 6 is 4.5° and the maximum angle within the lift portion 33 is 3-8°.

[0050] Within the crossover section 34 the bridge path extends over adjacent portions of the inner spiral track 7 and the outer spiral track 6. The longitudinal gradient angle within the crossover section 34 is still rather small in order to keep the height between the conveyor belt 10 and adjacent turns of the inner spiral track 7 and the outer spiral track 6 above the crossover section 34 as large as possible. The longitudinal gradient angle may be, for example, 1-3°.

[0051] Within the descending portion 35 and the connecting portion 36 the bridge path extends downwards until it reaches the inner helical track 7. The longitudinal gradient angles within the descending portion 35 and the connecting portion 36 are relatively large, for example 3-8°. The transition between the crossover portion 34 and the descending portion 35 is in fact close to the inner rail 7a of the inner helical track 7.

[0052] The first curve 8a of the bridge path has a steepest part that is steeper than the steepest part of the second curve 8b. The steepest part of the second curve 8b of the bridge path is a curve section 35", which is part of the descending part 35 and has a radius that is the same as the radius of a curve section 35' inside the descending part 35 located in the first curve 8a adjacent to the crossover part 34. The said radius of the curve section 35' is larger than the radius of the crossover part 34. More specifically, the crossover part 34 has a combination of a less steep longitudinal gradient and a smaller radius, when viewed from above, compared to the curve sections 35', 35" of the lifting part 33, the connecting part 36 and the descending part 35, respectively. The crossover portion 34 may be referred to as a first curved section of the first bridge 8 of the present invention, while each of the curved sections 35', 35" of the lift portion 33, the connecting portion 36, and the descending portion 35 may be referred to as a second curved section of the first bridge 8 of the present invention.

[0053] Between the first and second curves 8a, 8b, the descending part 35 has a straight section, which has a length greater than zero, for example greater than the width of one slat as measured in the conveying direction X. The straight section appears to be advantageous with regard to a stable transport of the products between the first and second curves 8a, 8b.

[0054] The application of a relatively small gradient and small radius in the crossover section is not necessarily related to other aspects as described in this application. In other words, the present invention also relates to the following aspects:

[0055] Aspect 1: An accumulating conveyor, comprising: a first spiral track and a second spiral track with coincident centerlines; a first S-shaped bridge and a second S-shaped bridge, each having a first curve in one direction and a second curve in the opposite direction when viewed from above; a first set of auxiliary guides and a second set of auxiliary guides; and an endless conveyor belt drivable in a conveying direction, the conveyor belt being guideable by said first and second spiral tracks, bridges and sets of auxiliary guides, such that under operating conditions the conveyor belt can be guided upwards on the first spiral track from its lower end to a location below its upper end, through the first bridge to a location below its upper end on the second spiral track, downwards on the second spiral track to its lower end, through the first set of auxiliary guides to an upper end of the second spiral track, downwards on the second spiral track, a second bridge to the first spiral track, upwardly along the first spiral track to its upper end, and a second set of auxiliary guides to a lower end of the first spiral track, the bridge being at least partially located on a common interior side of the first and second spiral tracks and simultaneously movable along the first and second spiral tracks to vary an effective length of the conveyor belt between the lower ends of the first and second spiral tracks via the first bridge on the one hand, and between the upper ends of the first and second spiral tracks via the second bridge on the other hand, each of said bridges having a longitudinal gradient that varies in the conveying direction along its respective bridge, and at least one of the first and second bridges having a first curved section that has a less steep longitudinal gradient and a smaller radius, as viewed from above, compared to the second curved section.

[0056] Aspect 2: An accumulating conveyor as described in aspect 1, wherein the first and second spiral tracks surround each other, such that the first and second spiral tracks extend radially adjacent to each other relative to their centerlines, or the first and second spiral tracks extend parallel to each other and lie on top of each other, such that they lie on a common imaginary cylinder and together follow a common spiral path.

[0057] Aspect 3: An accumulating conveyor as described in aspect 1, wherein the first and second spiral tracks surround each other such that the first and second spiral tracks extend adjacent to each other in a radial direction relative to their centerlines, and the first curve section extends at least partially over adjacent portions of the first and second spiral tracks.

[0058] Aspect 4: An accumulating conveyor as described in any of aspects 1 to 3, wherein the first curved portion of at least one of the first and second bridges includes a first curved section and a second curved section, but the second curved portion has a radius that is the same as the radius of the second curved section.

[0059] Aspect 5: An accumulating conveyor as described in aspect 4, wherein the second curved portion is located downstream of the first curved portion.

[0060] The inner spiral track 7 and the outer spiral track 6 are inclined inwards, for example by an inclination angle of 1°. The inner guide 23 and the outer guide 22 of the lower bridge 8 are also inclined inwards. Within the lift section 33 of the lower bridge 8, the inclination angle increases, for example, from 1° at the bridge inlet 31 to a maximum of 5° at the crossover section 34. This inclination angle is maintained in the crossover section 34 and decreases to zero in the middle straight section of the lower bridge 8, from where it increases again to a higher level up to the highest level within the second curved section 8b. Within the connecting section 36, the inclination angle decreases, for example, to 1° at the bridge outlet 32. It will be clear that the inner and outer guides of the upper bridge 9 can be arranged such that the curved sections of the upper bridge 9 are inclined inwards as well.

[0061] The trough-shaped inner and outer guides 23, 22 of the upper and lower bridges 9, 8 have an outer shape that differs from the outer shape of the trough-shaped inner rails 6a, 7a. The angle between the trough-shaped diverging walls of the inner and outer guides 23, 22 of the upper and lower bridges 9, 8 may be, for example, 14-20°.

[0062] 8 and 9 show in more detail the conveyor belt 10 including two slats 11; the other slats 11 are not shown for illustrative reasons. Each slat 11 is attached to a respective link of the chain 12. FIG. 10 shows the slat 11 with one of its guide rollers 20 supported upwards, downwards and radially by the inner rail 6a of the outer spiral track 6, and the slat 11 is also supported upwards by the outer rail 6b of the outer spiral track 6. The chain 12 is not shown in FIG. 10 for reasons of clarity. As the slat 11 is only supported upwards on the outer rail 6b, there may be a risk of the slat 11 being lifted up in places where there is excessive traction on the conveyor belt 10. This may also lead to the conveyor belt 10 tilting around the inner rail 6a. This risk is minimized by the shape and dimensions of the conveyor belt 10 and the inner rail 6a, illustrated in FIG. 10. The traction force on the chain 12 creates a resultant force F radially towards the centerline of the outer spiral track 6. To avoid tilting, the upper contact location 37 between one of the guide rollers 20 of each slat 11 and the inner rail 6a on which the guide roller 20 is radially supported must be located above the line along which the resultant radial force F of the chain 12 acts as can be seen in the cross section of the outer spiral track 6 illustrated in Figure 10. The upper contact location 37 may be the upper end of the line contact between the guide roller 20 and the inner rail 6a.

[0063] It is important that the shapes of the guide roller 20 and the inner rail 6a are carefully adapted to one another. For example, a combination of a cylindrical guide roller 20 with an inner rail 6a that includes a convex radial support surface should be avoided, since the convexity may result in an effective upper contact location 37 located close to or at the same height level as the line along which the resultant force F acts as seen in the cross section of the helical track 6.

[0064] 11 shows an embodiment in which the inner rail 6a is tilted slightly so that the upper contact location 37 between the cylindrical guide roller 20 and the inner rail 6a on which it is radially supported is located at the highest possible location. This is illustrated by the angle α between the opposing surfaces of the guide roller 20 and the inner rail 6a. In this case, there is a point contact between the guide roller 20 and the inner rail 6a rather than a line contact.

[0065] The situation relating to the inner rail 6a as described above also applies to the inner rail 7a of the inner spiral track 7.

[0066] The relationship between the location of the upper contact location and the radial line along which the resulting chain force acts on each slat does not necessarily relate to other features of the accumulating conveyor as shown in the drawings and described herein. In other words, the present invention also relates to the following aspects:

[0067] Aspect 1: A conveyor including a spiral track and a conveyor belt drivable along the spiral track, the spiral track including an inner rail and an outer rail surrounding the inner rail, the conveyor belt including slats mounted on a flexible conveyor line such as a sidebow chain, each slat including a guide roller having an axis of rotation with a vertical component, the guide rollers being supported upwardly, downwardly and radially by the inner rail, each slat being supported upwardly by the outer rail and being movable upwardly relative to the outer rail, and an upper contact location between the guide rollers and the inner rail along which the guide rollers are radially supported is located above a line along which a resultant radial force of the conveyor line toward the centerline of the inner rail acts. The guide rollers are supported radially by the inner rail, radially relative to the centerline of the inner rail.

[0068] Aspect 2: A conveyor as described in aspect 1, wherein the line along which the resultant radial force of the conveyor line acts towards the centerline of the inner rail intersects the centerline of the conveyor line, so that the upper contact location between the guide roller and the inner rail on which it is radially supported is located above the centerline of the conveyor line when viewed in a cross-sectional plane of the spiral track in which the centerline of the inner rail lies.

[0069] Aspect 3: A conveyor as described in aspect 1 or 2, wherein the guide roller is cylindrical and the inner rail has a trough shape including a bottom between a lower sidewall and an upper sidewall, the bottom supporting the guide roller radially from a centerline of the inner rail.

[0070] Aspect 4: A conveyor as described in aspect 3, wherein the guide rollers and inner rails of each slat are positioned such that the upper contact location is a point contact at the bottom adjacent the upper sidewall.

[0071] Figures 12 and 13 show the conveyor belt 10 inside the lower bridge 8. It can be seen that both guide rollers 20 of each slat 11 are accommodated in the respective trough-shaped inner and outer guides 23 and 22 of the lower bridge 8. This is also the case in the upper bridge 9. The height levels of the inner and outer guides 23 and 22 are different to create an inclination angle. Figure 12 illustrates one of the slats 11 in a normal situation, where both guide rollers 20 are located on the lower side walls 38 of the inner and outer guides 23 and 22, respectively. If the guide roller 20 in the outer guide 22 is lifted from its lower side wall 38, for example due to excessive traction on the conveyor belt 10, it will be stopped by the upper side wall 39 of the outer guide 22.

[0072] The angles between the lower sidewall 38 and the upper sidewall 39 of the inner guide 23 and the outer guide 22, respectively, are relatively small, for example 10-20°, limiting the range of inclination of the slats 11 inside the inner guide 23 and the outer guide 22. This is illustrated in FIG. 13. Furthermore, the conveyor belt 10, when in a traction-free state, can move in an outward direction inside the curve, so that the guide rollers 20 move in the transverse direction of the conveyor belt 10 on the lower sidewall 38 of the inner guide 23 and the outer guide 22. In the case of FIG. 12, this results in a displacement to the left, which results in a larger inclination angle. The relatively small angles between the lower sidewall 38 and the upper sidewall 39, respectively, limit the maximum variation of the inclination angle.

[0073] The relatively small angle between the respective lower sidewall 38 and upper sidewall 39 does not necessarily relate to other features of the accumulating conveyor as shown in the drawings and described herein. In other words, the present invention also relates to the following aspects:

[0074] an accumulating conveyor comprising first and second helical tracks with coincident centrelines, first and second S-shaped bridges each having a first bend in one direction and a second bend in the opposite direction when viewed from above, a first set of auxiliary guides and a second set of auxiliary guides, and an endless conveyor belt drivable in a conveying direction, the conveyor belt being guideable by said first and second helical tracks, bridges and sets of auxiliary guides, so that under operating conditions the conveyor belt follows successively the first spiral track from its lower end upward to a location below its upper end, the first bridge to a location on the second spiral track below its upper end, the second spiral track downward to its lower end, the first set of auxiliary guides to the upper end of the second spiral track, the second spiral track downward, the second bridge to the first spiral track, the first spiral track upward to its upper end, and the second set of auxiliary guides to the lower end of the first spiral track. The bridge is at least partially located on a common inner side of the first and second helical tracks and is simultaneously movable along the first and second helical tracks to vary an effective length of the conveyor belt between lower ends of the first and second helical tracks via the first bridge on the one hand and between upper ends of the first and second helical tracks via the second bridge on the other hand, the conveyor belt including slats mounted on a flexible conveyor line such as a sidebow chain, the slats being spaced apart from each other in a transverse direction of the conveyor belt. 1. An accumulating conveyor comprising: two guide rollers, each having an axis of rotation including a vertical component; first and second bridges each comprising inner and outer guides for guiding the respective guide rollers, each of the inner and outer guides having a trough shape including a lower sidewall, an upper sidewall, and a bottom between the lower sidewall and the upper sidewall, the lower and upper sidewalls diverging when viewed from the bottom, and at least one of the lower and upper sidewalls having a diverging angle relative to the bottom that is less than 110°, preferably less than 100°.

[0075] It is noted that the inner rails 6a, 7a may have a trough shape to support the guide rollers 20 of the conveyor belt 10 upward, downward and radially, but the angle between the diverging walls of the trough shape may be larger than in the case of the inner guides 23 and outer guides 22 of the bridges 8, 9, e.g. 40°. The diverging angle of the inner rails 6a, 7a is not as critical as in the case of the bridges 8, 9 in terms of inclination variations due to the relatively large radius of the inner rails 6a, 7a, so the effect of inclination variations on the maximum allowable speed of the conveyor belt 10 is limited compared to the bridges 8, 9.

[0076] Figures 14 and 15 show the upper side of the accumulating conveyor 1 in more detail. At the upper ends 15, 19 of the inner and outer spiral tracks 7, 6, the accumulating conveyor 1 comprises two outer rail guides 40 for guiding the slats 11 at the respective transitions between the outer rails 6b, 7b and the upper sprockets 16, 17 of the accumulating conveyor 1, in order to avoid the conveyor belt 10 from displacing in the outward direction of the inner and outer spiral tracks 7, 6. Before approaching one of the outer rail guides 40, the conveyor belt 10 must rest on the corresponding outer rail 6b, 7b in order to avoid a part of one of the slats 11 colliding with the corresponding rail guide 40. This is ensured by the presence of two series of convergence rollers 44 above the conveyor belt 10. See Figure 14. In practice, depending on the conveying direction of the conveyor belt 10, only one series of converging rollers 44 is required to address the aforementioned risks, but if the conveyor belt 10 is also driven in the opposite direction, both series of converging rollers may be applied.

[0077] 16 and 17 show a protective carriage 41, which is suitable for preventing the conveyor belt 10 from completely derailing in case of an unexpected derailment of the conveyor belt 10 above the accumulating conveyor 1, for example due to excessive traction forces on the conveyor belt 10. In particular in case of small accumulation areas, the distance of the conveyor belt 10 along the outer spiral track 6 between the upper bridge 9 and the upper end 15 of the outer spiral track 6 is relatively long, resulting in relatively high traction forces in the conveyor belt 10 in the upper part of the outer spiral track 6 adjacent to the sprocket 17, and thus a risk of derailment due to tilting of the conveyor belt 10 around the inner rail 6a of the outer spiral track 6.

[0078] The protective carriage 41 has a U-shaped frame 42 which moves freely along the inner and outer spiral tracks 7, 6 through carriage rollers 43. Under normal operating conditions, when the lower and upper bridges 8, 9 are in a relatively low position, the protective carriage 41 is located, for example, at a distance of half a turn from the upper ends 15, 19 of the inner and outer spiral tracks 7, 6, where it abuts against a stop element (not shown) to prevent the protective carriage 41 from moving further downwards. Such a location is illustrated in FIG. 1. However, this distance may be different. If a large accumulation area is required, the upper bridge 9 pushes the protective carriage 41 upwards along the inner and outer spiral tracks 7, 6, over the stop element, until it stops at the upper ends 15, 19 of the first and second spiral tracks 6, 7.

[0079] The function of the protective carriage 41 is as follows: if the upper bridge 9 and the lower bridge 8 are at a relatively low height and the conveyor belt 10 derails unexpectedly above the upper bridge 9, for example at the upper end 15 of the outer spiral track 6, this is detected by a sensor (not shown) and the motors 13, 14 are immediately switched off. To avoid the derailment proceeding like a chain reaction downwards along the inner spiral track 7 and the outer spiral track 6, the protective carriage 41 limits the length of the derailment by means of wheels 45 on the inside of the frame 42 of the protective carriage 41. The wheels 45 prevent the cooperating slats 11 from tilting around the inner rails 6a, 7a. If the protective carriage 41 is located, for example, half a turn from the upper ends 15, 19 of the inner spiral track 7 and the outer spiral track 6, the derailment is limited to that distance.

[0080] The protective carriage does not necessarily relate to other features of the accumulating conveyor as shown in the drawings and described herein. In other words, the present invention also relates to the following aspects:

[0081] Aspect 1: An accumulating conveyor, comprising: a first helical track and a second helical track with coincident centerlines; a first S-shaped bridge and a second S-shaped bridge, each having a first curved portion in one direction and a second curved portion in the opposite direction when viewed from above; a first set of auxiliary guides and a second set of auxiliary guides; and an endless conveyor belt that is drivable in a conveying direction, the conveyor belt being guideable by said first and second helical tracks, bridges and sets of auxiliary guides, so that the conveyor belt is operable. Under the conditions, the conveyor belt continues to travel up the first spiral track from its lower end to a location below its upper end, over the first bridge to a location below its upper end on the second spiral track, down the second spiral track to its lower end, over the first set of auxiliary guides to the upper end of the second spiral track, down the second spiral track, over the second bridge to the first spiral track, up the first spiral track to its upper end, and over the second set of auxiliary guides to the lower end of the first spiral track. and a bridge located at least partially within a common interior of the first and second spiral tracks and movable simultaneously along the first and second spiral tracks to vary an effective length of the conveyor belt between lower ends of the first and second spiral tracks via the first bridge on the one hand and between upper ends of the first and second spiral tracks via the second bridge on the other hand, the first and second spiral tracks each including an inner rail and an outer rail surrounding the inner rail, the conveyor belt being movable upwardly, downwardly and radially by the inner rail. the accumulating conveyor includes a protective carriage supported upwardly and upwardly by the outer rail and movable upwardly relative to the outer rail, the accumulating conveyor being freely movable along at least one of the first and second spiral tracks between an upper end thereof and a stop element spaced from the upper end thereof, the protective carriage including a retaining member located above the conveyor belt at the protective carriage to minimize lifting of the conveyor belt from the outer rail, the second bridge and the protective carriage including:An accumulating conveyor comprising cooperating engagement elements adapted to enable the second bridge to push the protective carriage upwards along said at least one of the first and second spiral tracks. The cooperating engagement elements may be simple contact surfaces on the protective carriage and the upper bridge. This function of the protective carriage may be considered as a damage control system. In case of overloading of the conveyor belt, for example the upper half turn may derail in a controlled manner resulting in instantaneous belt tension relief. The retaining member may be located above the conveyor belt at the outer rail of the first spiral track only if the conveying direction is always the same.

[0082] Aspect 2: The conveyor according to aspect 1, wherein the drive motor for driving the conveyor belt is located in the second set of auxiliary guides and the protective carriage is located in the first spiral track. In this case, the drive motor generates a relatively high traction force on the conveyor belt in the first spiral track, which creates the highest risk of derailment.

[0083] Aspect 3: A conveyor as described in aspect 1 or 2, wherein the protective carriage is located on the first and second spiral tracks, and the retaining member is located above the conveyor belt on both the first and second spiral tracks.

[0084] FIG. 18 shows an embodiment in which two accumulating conveyors 1 are arranged in succession. In comparison with the embodiment as shown in FIG. 1, the left part of the embodiment of FIG. 18 can be considered as including a first 6 and a second 7 helical track, a first 8 and a second 9 bridge, and a set of a second auxiliary guide 17, while the right part can be considered as including a set of a first auxiliary guide 16. In this case, the set of the first auxiliary guide 16 includes an additional first 6' and a second 7' helical track, as well as an additional first 8' and a second 9' bridge, which function similarly to the left part of the embodiment as shown in FIG. 18. The accumulation area extends from the product inlet 4, via the first bridge 8 in the left part and the additional first bridge 8' in the right part, to the product outlet 5. With this arrangement, the speed of the conveyor belt 10 between the first bridge 8 of the left part and the additional first bridge 8' of the right part is half the speed of the conveyor belt 10 at the product outlet 5 when the speed of the conveyor belt 10 at the product inlet 4 is zero. The same effect occurs when the speed at the product outlet 5 is zero but the speed at the product inlet is not zero. Due to the reduced speed, less drive force is required. Figure 19 shows an alternative embodiment, which is less preferred since the total length of the conveyor belt 10 is longer compared to the embodiment as shown in Figure 18.

[0085] In a more general aspect, the invention also relates to the following aspects:

[0086] An accumulating conveyor, comprising first and second helical tracks with coincident centerlines, first and second S-shaped bridges each having a first curve in one direction and a second curve in the opposite direction when viewed from above, a first set of auxiliary guides and a second set of auxiliary guides, and an endless conveyor belt drivable in a conveying direction, the conveyor belt being guideable by said first and second helical tracks, bridges and sets of auxiliary guides, so that an operating condition Below, the conveyor belt continues up the first spiral track from its lower end to a location below its upper end, over the first bridge to a location below its upper end on the second spiral track, down the second spiral track to its lower end, over the first set of auxiliary guides to the upper end of the second spiral track, down the second spiral track, over the second bridge to the first spiral track, up the first spiral track to its upper end, and over the second set of auxiliary guides to the lower end of the first spiral track. a bridge located at least partially on a common inner side of the first and second helical tracks and movable simultaneously along the first and second helical tracks to vary an effective length of the conveyor belt between lower ends of the first and second helical tracks via the first bridge on the one hand and between upper ends of the first and second helical tracks via the second bridge on the other hand; and a first set of auxiliary guides for the additional first helical track and the additional second helical track including coincident centerlines and a first curved portion in one direction when viewed from above. and an additional first S-shaped bridge and an additional second S-shaped bridge, each having a second curved portion in an opposite direction, the additional bridges being at least partially located on a common inside of the additional first and second spiral tracks and simultaneously movable along the additional first and second spiral tracks, and an additional set of first auxiliary guides, in which the conveyor belt is guided from a lower end of the second spiral track to a lower end of the additional first spiral track.The accumulating conveyor follows the additional first bridge upward from its lower end to a location below its upper end, the additional second spiral track downward to its lower end, the additional first set of auxiliary guides to the upper end of the additional second spiral track, the additional second bridge downward to the additional first spiral track, the additional first spiral track upward to its upper end, and thence to the upper end of the second spiral track. This embodiment may be combined with features relating to other embodiments as disclosed herein. For example, inclinations, different radii, and gradient angles may be applied at the bridge and the additional bridge. In practice, the first and second spiral tracks may be located at a distance from the additional first and second spiral tracks.

[0087] 20 and 21 show another embodiment of the invention. In this case, the inner rails 6a, 7a and the outer rails 6b, 7b are supported by a helical plate 46. This seems to create a rigid support even in the case of a relatively thin helical plate. Thus, the first helical track 6 and the second helical track 7 can be supported by a relatively thin helical plate 46 instead of the conventional relatively thick rods that extend radially to the centerlines of the inner helical track 7 and the outer helical track 6 and are arranged at an angular distance to each other around the centerlines of the inner helical track 7 and the outer helical track 6. The sum of the heights of the helical plate 46 and the inner rails 6a, 7a and the outer rails 6b, 7b, respectively, can be minimized. The spiral plate 46 can be made by deformation of a ring-shaped plate, which includes a gap in the radial direction of the ring-shaped plate, where the end portions of the ring-shaped plate on both sides of the gap are displaced relative to each other in a direction perpendicular to the plane of the ring-shaped plate and attached to the frame 2. Due to the aforementioned displacement, the ring-shaped plate automatically deforms into a spiral shape. Figures 20 and 21 show that the spiral plate 46 is fixed to the frame 2 by a flat rod 47. Several such spiral plates 46 can be mounted behind each other to form multiple turns.

[0088] The application of the spiral plate does not necessarily relate to other aspects as described in this application. In other words, the present invention also relates to the following aspects:

[0089] Aspect 1: A spiral conveyor comprising a drivable conveyor belt supported and guided by a spiral rail, the rail being supported by a spiral plate, the spiral plate being fixed to a frame.

[0090] Aspect 2: A spiral conveyor as described in aspect 1, wherein the spiral plate is made by deformation of a ring-shaped plate, the ring-shaped plate including a gap in the radial direction of the ring-shaped plate, and the end portions of the ring-shaped plate on either side of the gap are displaced relative to each other in a direction perpendicular to the plane of the ring-shaped plate and are attached to a frame.

[0091] In practice, the spiral conveyor may comprise a number of such spiral plates, which may be fixed to each other and to the frame.

[0092] Fig. 22 shows an exemplary drawing of an alternative embodiment of the accumulating conveyor 1. This embodiment comprises connections 48 between the respective portions of the conveyor belt 10 at the lower bridge 8 and the upper bridge 9. The connections 48 transmit the drive force between the respective portions of the conveyor belt 10 at the respective lower bridge 8 and upper bridge 9. In this case, the connections 48 are formed by sprockets that engage the chains 12 of the conveyor belt 10 at the lower bridge 8 and the upper bridge 9, although alternative configurations are conceivable.

[0093] The function of the connection 48 can be explained by the following example: If the lower bridge 8 and the upper bridge 9 are at a relatively high level in the accumulating conveyor 1 and the electric motor 14 at the product inlet 4 pulls the conveyor belt 10, the level of traction force on the conveyor belt 10 immediately downstream of the product inlet 4 is low, but increases significantly during the movement towards the lower bridge 8 due to the pulling force of the electric motor 13 at the product outlet 5 and the relatively large number of turns that the conveyor belt 10 follows on its way to the lower bridge 8. As the conveyor belt 10 follows a spiral path, the required traction force increases exponentially with the number of turns. On the other hand, the electric motor 14 at the product inlet 4 can exert a relatively high pulling force on the conveyor belt 10 at the upper bridge 9, since in this state the number of turns between the upper bridge 9 and the electric motor 14 at the product inlet 4 is relatively small. Due to the presence of the linkage 48, the portion of the conveyor belt 10 at the upper bridge 9 can in this situation drive the portion of the conveyor belt 10 at the lower bridge 8. In another situation, if the bridges 8, 9 are located at a relatively low position in the accumulating conveyor 1, the portion of the conveyor belt 10 at the lower bridge 8 can drive the portion of the conveyor belt 10 at the upper bridge 9 through the linkage 48. As a result, the presence of the linkage 48 can smooth out traction force peaks in the conveyor belt 10.

[0094] The application of the connector does not necessarily relate to other aspects as described in this application. In other words, the present invention also relates to the following aspects:

[0095] Aspect 1: An accumulating conveyor, comprising: a first helical track and a second helical track with coincident centerlines; a first S-shaped bridge and a second S-shaped bridge, each having a first curve in one direction and a second curve in the opposite direction when viewed from above; a first set of auxiliary guides and a second set of auxiliary guides; and an endless conveyor belt drivable in a conveying direction, the conveyor belt being guideable by said first and second helical tracks, the bridges and the set of auxiliary guides, such that under operating conditions the conveyor belt can be guided upwards on the first helical track from its lower end to a location below its upper end, the first bridge to a location below its upper end on the second helical track, the second helical track downwards to its lower end, the first set of auxiliary guides above the second helical track. the bridge is at least partially located within a common interior of the first and second spiral tracks and is movable simultaneously along the first and second spiral tracks to vary an effective length of the conveyor belt between the lower ends of the first and second spiral tracks via the first bridge on the one hand and between the upper ends of the first and second spiral tracks via the second bridge on the other hand, the conveyor comprising a connection between respective portions of the conveyor belt at the first bridge and the second bridge for transmitting a drive force between respective portions of the conveyor belt at the respective first and second bridges.

[0096] Aspect 2: An accumulating conveyor as described in aspect 1, wherein a straight portion is present between the first curved portion and the second curved portion of each of the first and second bridges, and the connecting portion engages a portion of the conveyor belt at each straight portion.

[0097] The present invention is not limited to the embodiments shown in the drawings and described herein above, which may be varied in various ways within the scope of the claims and their technical equivalents. For example, the conveying direction of the conveyor belt may be in the opposite direction, but the product inlet and product outlet are reversed. It is also possible for the product inlet and product outlet to be located in different places than shown in the drawings.

[0098] Furthermore, the accumulation area and the empty area may be reversed, so that the product inlet and product outlet may be located at the upper ends of the respective inner and outer spiral tracks. In this case, the upper bridge forms part of the accumulation area, while the lower bridge forms part of the empty area. The function of the accumulating conveyor is essentially the same as in the embodiment described above and shown in the drawings. [Explanation of symbols]

[0099] 1 Accumulating conveyor 2 Frames 3 legs 4 Product entrance 5 Product outlet 6 Outer spiral track 6a Inner rail 6b Outer rail 6' Additional 1st spiral track 7 Inner Spiral Track 7a Inner rail 7b Outer rail 7' 2nd spiral track 8 Lower S-shaped bridge 8a First curved portion 8b Second curved section 8' Additional 1st Bridge 9 Upper S-shaped bridge 9' Additional 2nd Bridge 10 Endless Conveyor Belt 11 Slat 12 Chain 13 Electric motor 14 Electric motor 15 Upper end 16 Sprockets 16 Auxiliary Guide 17 Sprocket 17 Auxiliary Guide 18 Lower end 19 Upper end 20 Lower end 20 Guide roller 21 Diverter 22 Outer guide 23 Inner guide 24 Bottom Plate 25 Cutout 26 Wheels 27 Bridge Roller 28 Chain 29 Chain 30 Chain 31 Bridge Entrance 32 Bridge Exit 33 Lift section 34 Crossover section 35 Descending part 35' Curved Section 35” Curved Section 36 Connecting part 37 Upper contact location 38 Lower side wall 39 Upper side wall 40 Outer rail guide 41 Protective carriage 42 U-shaped frame 43 Carriage roller 44 Converging roller 45 Wheels 46 Spiral Plate 47 Flat Rod 48 Connecting part F force X Transport direction α angle

Claims

1. An accumulating conveyor (1), comprising: a first helical track (6) and a second helical track (7) having coincident centrelines; a first S-shaped bridge (8) and a second S-shaped bridge (9), each having a first curved portion (8a) in one direction and a second curved portion (8b) in the opposite direction when viewed from above; a first set of auxiliary guides (16) and a second set of auxiliary guides (17); an endless conveyor belt (10) that is drivable in a conveying direction (X); Including, The conveyor belt (10) can be guided by the first and second spiral tracks (6, 7), the bridges (8, 9) and the set of auxiliary guides (16, 17), so that under operating conditions, the conveyor belt (10) can move upwards along the first spiral track (6) from its lower end (18) to a location below its upper end (15), along the first bridge (8) to a location below its upper end (19) in the second spiral track (7), and along the second bridge (8) to a location below its upper end (19). successively following the spiral track (7) downward to its lower end (20), the set of first auxiliary guides (16) to the upper end (19) of the second spiral track (7), the second bridge (9) downward to the first spiral track (6), the first spiral track (6) upward to its upper end (15) and the set of second auxiliary guides (17) to the lower end (18) of the first spiral track (6); said bridge (8, 9) is at least partially located on a common inside of said first and second helical tracks (6, 7) and is movable simultaneously along said first and second helical tracks (6, 7) to vary an effective length of said conveyor belt (10) between said lower ends (18, 20) of said first and second helical tracks (6, 7) via said first bridge (8) on the one hand and between said upper ends (15, 19) of said first and second helical tracks (6, 7) via said second bridge (9) on the other hand, At least a portion of the first and second curved portions (8a, 8b) of at least one of the first and second bridges (8, 9) are inclined inwardly therefrom. An accumulating conveyor (1).

2. said first and second spiral tracks (6, 7) surround each other so that they extend radially adjacent to each other relative to their centre lines, or 2. An accumulating conveyor (1) as claimed in claim 1, wherein the first and second spiral tracks (6, 7) extend parallel to each other and lie on top of each other, so that they lie on a common imaginary cylinder and together follow a common spiral path.

3. 3. An accumulating conveyor (1) according to claim 1 or 2, wherein at least one of the first and second bridges (8, 9) has a first curved section (34) which has a less steep longitudinal gradient in the conveying direction (X) and a smaller radius in a top view compared to the second curved section (33, 35, 36).

4. said first and second spiral tracks (6, 7) surround each other, so that said first and second spiral tracks (6, 7) extend radially adjacent to each other relative to their centre lines; 4. An accumulating conveyor (1) according to claim 3 and based on claim 1, wherein the first curved section (34) extends at least partially over adjacent portions of the first and second spiral tracks (6, 7).

5. 5. An accumulating conveyor (1) according to claim 3 or 4, wherein the first curved portion (8a) of at least one of the first and second bridges (8, 9) comprises the first curved section (34) and the second curved section (35'), while the second curved portion (8b) has the same radius as the radius of the second curved section (35').

6. 6. An accumulating conveyor (1) according to claim 5, wherein the second curved portion (8b) is located downstream of the first curved portion (8a).

7. 7. An accumulating conveyor (1) according to any one of claims 1 to 6, wherein the conveyor comprises connections (48) between respective portions of the conveyor belt (10) at the first bridge (8) and the second bridge (9) for transmitting drive force between the respective portions of the conveyor belt (10) at the first and second bridges (8, 9).

8. 8. An accumulating conveyor (1) according to any one of claims 1 to 7, wherein at least one of the first and second bridges (8, 9) is radially supported by at least one of the first and second spiral tracks (6, 7) at least via a bridge roller (27) provided on said at least one of the first and second bridges (8, 9), said bridge roller (27) resting on said at least one of the first and second spiral tracks (6, 7).

9. the bridge roller (27) is located at at least one of a bridge inlet (31) and a bridge outlet (32) of at least one of the first and second bridges (8, 9); An accumulating conveyor (1) according to claim 8.

10. said first and second spiral tracks (6, 7) each including an inner rail (6a, 7a) and an outer rail (6b, 7b) for guiding said conveyor belt (10); 10. An accumulating conveyor (1) according to any one of claims 1 to 9, wherein the inner and outer rails (6a, 7a, 6b, 7b) are supported by a spiral plate (46).

11. said first and second bridges (8, 9) are connected to each other through an elongated curved connecting element (28) extending at least between said first and second bridges (8, 9) along at least one of said first and second helical tracks (6, 7); and / or An accumulating conveyor (1) according to any one of claims 1 to 10, wherein two spaced apart portions of at least one of the first and second bridges (8, 9) are fixed to another elongated curved connecting element (29, 30) extending along one of the first and second spiral tracks (6, 7) between the two spaced apart portions.

12. 12. The accumulating conveyor (1) according to claim 11, wherein at least one of the elongated curved connecting element (28) and the further elongated curved connecting element (29, 30) is flexible and is guided by a corresponding one of the first and second spiral tracks (6, 7).

13. each of the first and second spiral tracks (6, 7) comprises an inner rail (6a, 7a) and an outer rail (6b, 7b) surrounding the inner rail (6a, 6b); the conveyor belt (10) is upwardly, downwardly and radially supported by the inner rails (6a, 7a) and upwardly supported by the outer rails (6b, 7b) and is upwardly movable relative to the outer rails (6b, 7b); said accumulating conveyor (1) comprises a protective carriage (41) freely movable along at least one of said first helical track (6) and said second helical track (7) between said upper end (15, 19) and a stop element spaced from said upper end (15, 19); the protective carriage (41) includes a retaining member (45) located above the conveyor belt (10) on the protective carriage (41) to minimize lifting of the conveyor belt (10) from the outer rails (6b, 7b); 13. An accumulating conveyor (1) according to any one of claims 1 to 12, wherein the second bridge (9) and the protective carriage (41) are provided with cooperating engagement elements adapted to enable the second bridge (9) to push the protective carriage (41) upwards along the at least one of the first and second spiral tracks (6, 7).

14. Each of the spiral tracks (6, 7) comprises an inner rail (6a, 7a) and an outer rail (6b, 7b) surrounding the inner rail (6a, 7a); The conveyor belt (10) comprises slats (11) attached to a flexible conveyor line (12), each of said slats (11) comprises two guide rollers (20) spaced apart from each other in a transverse direction of said conveyor belt (10), each guide roller (20) having an axis of rotation with a vertical component; one of the guide rollers (20) of each slat (11) is supported upwardly, downwardly and radially by the inner rail (6a, 7a); a portion of each slat is supported upwardly by the outer rail (6b, 7b) and is upwardly movable relative to the outer rail (6b, 7b); 14. An accumulating conveyor (1) according to any one of claims 1 to 13, wherein an upper contact location (37) between each of the guide rollers (20) and the inner rail (6a, 7a) on which it is radially supported is located above a line along which a resultant radial force of the conveyor line (12) towards the centre line of the first and second spiral tracks (6, 7) acts.

15. The conveyor belt (10) comprises slats (11) attached to a flexible conveyor line (12), Each of the slats (11) comprises two guide rollers (20) spaced apart from each other in a transverse direction of the conveyor belt (10), each of the guide rollers (20) having an axis of rotation with a vertical component; said first and second bridges (8, 9) each comprising an inner and outer guide (22, 23) for guiding said respective guide roller (20); Each of the inner and outer guides (22, 23) has a trough shape including a lower sidewall (38), an upper sidewall (39), and a bottom between the lower and upper sidewalls (38, 39); said lower and upper side walls (38, 39) diverge when viewed from said bottom; 15. An accumulating conveyor (1) according to any one of the preceding claims, wherein at least one of the lower and upper side walls (38, 39) has a diverging angle with respect to the base, the diverging angle being smaller than 100°.

16. An accumulating conveyor (1) as described in claim 14 or 15, wherein the flexible conveyor line (12) is a side bow chain.

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