A conveyor device

Abstract

A conveyor device comprising an endless track which follows a track path in a transport direction, which track path comprises at least one straight section and multiple curved sections in horizontal direction, wherein at least one of said curved sections forms a left curved section and at least one other one of said curved sections forms a right curved section; a plurality of carriers distributed in a closed loop along said track, wherein each carrier comprises a rectangular support surface for carrying one or more objects; driving means for moving said plurality of carriers along said track; wherein said conveyor device is configured such that while moving along said at least one straight section the distance between adjacent sides of two adjacent support surfaces is smaller than the average distance between the support surfaces while moving along said left curved sections and smaller than the average distance between the support surfaces while moving along said right curved sections.

Description

[0001]A conveyor device The present invention relates to a conveyor device comprising: an endless track which follows a track path in a transport direction, which track path comprises at least one straight section and multiple curved sections in horizontal direction, wherein at least one of said curved sections forms a left curved section and at least one other one of said curved sections forms a right curved section; a plurality of carriers distributed in a closed loop along said track, wherein each carrier comprises a rectangular support surface for carrying one or more objects; driving means for moving said plurality of carriers along said track; wherein said conveyor device is configured such that: while moving along said at least one straight section the distance between adjacent sides of two adjacent support surfaces is while moving along said left curved sections on the right-hand side the distance between adjacent corners of said support surfaces is xleftand on the left-hand side the distance between adjacent corners ofsaid support surfaces is yleft; andwhile moving along said right curved sections on the right-hand side the distance between adjacent corners of said support surfaces is xrightand on the left-hand side the distance between adjacent corners of said support surfaces is yright. Conveyor devices, such as cross-belt sorters, are well known, for instance as disclosed in US 6,253,901 B1. An example of such a device is shown in and described with reference to Figs. 1A-C and Fig. 2. These conveyor devices may be used in sorter systems, wherein objects, such as packages which are to be sorted and sent to many different destinations, are transported from a loading or induction position to respective receiving positions. These receiving positions are usually located along the straight sections of the endless track, at both sides thereof, and usually are formed by chutes into which the objects are ejected. Each receiving position corresponds to a (group of) different destinations or clients. The curves in the track path preferably have a small radius in order to save space (i.e. to increase the length of the straight sections and to decrease the gap between the adjacent straight sections. There is a desire to increase the capacity of the devices and / or minimize the radius of the curves. To this end, a conveyor device according to the preamble is characterized in that said conveyor device is further configured such that while moving along said at least one straight section the distance dstraightbetween adjacent sides of two adjacent supportsurfaces is smaller than the average distance (yleft + xleft) / 2 betweenthe support surfaces while moving along said left curved sections andsmaller than the average distance (xright + yright) / 2 between the supportsurfaces while moving along said right curved sections. It should be noted that, where reference is made to a "rectangular support surface", that this does not necessarily mean that the rectangular support surface is formed and delimited by a rectangular top side of the carrier. The rectangular support surface in this respect may also be a rectangular area within a differently shaped top side of the carrier. Furthermore, a "rectangular support surface" may also be composed of more than one support surfaces on one carrier (as shown for instance in Figs. 7A and 7B). It should furthermore be noted, that where reference is made to "left", "right", "front" and "rear", this is seen in the transport direction as indicated by the arrows in Figs. 2 and 3. Reference is made to Figs. 7A and 7B. In prior art devices with left and right curved sections, as shown in Fig. 7A, the carriers aremutually connected in the centre and the distance (dstraight) between thesupport surfaces in the straight sections is the average of the distances between the support surfaces in the curved sections, inother words: dstraight = (xleft + yleft) / 2 = (xright + yright) / 2.According to the invention, as shown in Fig. 7B, the device isconstructed such that the distance (dstraight) between the supportsurfaces in the straight sections is substantially smaller than theaverage distances (xleft + yleft) / 2 and (xright + yright) / 2 between thesupport surfaces in the curved sections. Thereby, in the straight sections of the track more carriers, and thereby more support surfaces, can be accommodated than in the prior art devices. In the configurations as shown in Figs. 2 and 3 the capacity of the conveyor device according to the invention as shown in Fig. 3 (179 carriers) is increased by 14 % compared to the prior art conveyor device as shown in Fig. 2 (157 carriers). Other prior art devices, which only comprise straight track parts and curved section track parts with either only left curved sections or only right curved sections, comprise carriers which are mutually connected at the inner side of the curved sections, such that thedistance (dstraight) between the support surfaces in the straightsections is also substantially smaller than the average distances(xleft + yleft) / 2 and (xright + yright) / 2 between the support surfaces in thecurved sections. According to the invention this principle can be carried over to tracks which have both left curved sections and right curved sections. To this end, however, the concept of fixed connections between the carriers at the inner side of the curved sections cannot be used, and alternative connection concepts or drive concepts are necessary, as described below. The driving means, which may for instance comprise a driven wheel or a gear wheel engageable with a friction surface or a toothed rack on the carriers, or which may comprise a linear motor, may dive carriers forward in at least one driving location along the endless track, such that the driven carrier at said driving location will push the carriers in front of it forward and / or pull the carriers behind it forward. The driving means may also comprise multiple drive units at multiple driving locations along the endless track. The driving means may also comprise a distributed driving means, such as a linear motor, distributed along substantially the entire length of the endless track, such that substantially all of the carriers are driven at once. According to a favourable embodiment, said distances dstraight, yleftand xrightbetween the support surfaces are substantially equal. According to an especially preferred embodiment, while moving along respectively said at least one straight section, said left curved sections and said right curved sections the carriers are in contact with each other at respectively both sides, the left-hand side, and the right-hand side. In other words, in the preferred embodiment the construction of the device is such that two adjacent carriers always touch each other, whether they are moved along a straight section, a left curve or a right curve. According to a preferred embodiment, each of said carriers is arranged to contact and push the adjacent carrier at its front side, wherein in the left curved sections the carriers contact and push each other at the left-side and in the right curved sections the carriers contact and push each other at the right-hand side. Preferably, each carrier is provided with bumpers at the right hand side and the left hand side. The bumpers may reduce the noise and wear when the carriers bump into each other, and furthermore the bumpers may be deformable by the force of the contact between the carriers. According to another embodiment, the carriers are mutually connected by releasable connection means at their left-hand side and their right-hand side, and said conveyor device provided with means for releasing the connection between the carriers at the left-hand side before or when the carrier enters a right curved section, and for releasing the connection between the carriers at the right-hand side before or when the carrier enters a left curved section, and with means for re-establishing the respective connection after or when the carrier leaves the respective curve. The respective connections may for instance be a mechanical snap or latching connection, or a magnetic or electromagnetic connection, and the connections may be self-locking and -unlocking depending on changing pull / push forces between the carriers, or they may be actively locked and / or unlocked by means of activators before and / or after each curve. According to another embodiment, the carriers are mutually connected by releasable connection means at their centre between the left-hand side and the right-hand side, wherein the connection between the carriers is constructed such that if the releasable connection means is released, the distance between the carriers is allowed to increase to a maximum distance, and with means for re-establishing the respective connection after or when the carrier enters the straight section. Said maximum distance is preferably such that in the sharpestcurved section in the endless track the distance (yleft, xright) betweenthe carriers at the side of the inside curved section is zero or almost zero. The above-mentioned preferred embodiments are not mutually exclusive and are preferably combined. For instance, the embodiment wherein the carriers are arranged to contact and push each other, preferably with the mentioned bumpers, is preferably combined with embodiments wherein the carriers are mutually connected by connection means at the sides and / or in the centre, so that they are also arranged to pull each other. Preferably, the releasable connection means comprise mechanical activator means for unlocking the respective connection at or before the start of each respective curve. The releasable connection means may also comprise mechanical activator means for locking the respective connection at or after the end of each respective curve. Preferably, said releasable connection means comprise a latch mechanism with a latch to establish said connection and said mechanical activator means comprise a guide surface located along the endless track which pushes against the latch when the carrier passes said guide surface in order to unlock the latch and release said connection. Preferably, said latch is spring loaded such that the latch automatically locks and re-establishes the respective connection when the carriers move along the straight sections of the endless track. According to an especially preferred embodiment, said support surfaces are formed by top surfaces of a cross-belt conveyor. In a cross-belt conveyor the support surfaces of each carrier are formed by the top surfaces of a small endless conveyor belt, whereby objects on the support surface can move from and be supplied to either side of the cross-belt conveyor. According to an especially preferred embodiment, the conveyor device is a sorter device. The present invention will now be illustrated with reference to the drawing where Fig. 1A is a top perspective view of a part of a prior art cross-belt conveyor device; Fig. 1B is a bottom perspective view a part of the prior art cross-belt conveyor device; Fig. 1C is a rear view of a part of the prior art cross-belt conveyor device; Fig. 2 is a schematic top view of the prior art conveyor device; Fig. 3 is a schematic top view of a conveyor device in accordance with the invention; Fig. 4A is a top perspective view of a part of a first embodiment of a cross-belt conveyor device; Fig. 4B is a bottom view of the part of the first embodiment of a cross-belt conveyor device; Fig. 4C is a detailed top perspective view of the part of the first embodiment of a cross-belt conveyor device; Fig. 5A is a top perspective view of a part of a second embodiment of a cross-belt conveyor device; Fig. 5B is a bottom perspective view of the part of the second embodiment of a cross-belt conveyor device; Fig. 5C is a detailed bottom view of the part of the second embodiment of a cross-belt conveyor device; Fig. 6A is a top perspective view of a part of a third embodiment of a cross-belt conveyor device; Fig. 6B is a detailed bottom perspective view of the part of the third embodiment of a cross-belt conveyor device; Fig. 6C is a detailed side view of the part of the third embodiment of a cross-belt conveyor device in a latched state; Fig. 6D is a detailed perspective view of the part of the third embodiment of a cross-belt conveyor device in an unlatched state without a cross belt for better visibility; and Figs. 7A and 7B are respective schematic top views of conveyor devices in accordance with the prior art and the invention. With reference to Figs. 1A-C, a cross-belt sorter of the type as disclosed in US 6,253,901 B1, the disclosure of which is incorporated herein by reference, comprises a conveyor device 101. The conveyor device 101 comprises a base frame 110 which carries guide rails 114, 115, together forming a track of the conveyor device 101. A plurality of carriers 111 positioned consecutively in a conveying direction, flexibly connected to each other and forming an endless conveying line for loading of objects 104 on each of the carriers 111. Each carrier 111 at the central section of its front side 112 and the central section of its rear side 113 is pivotably connected to the adjacent carrier 111. A cross-belt conveyor is mounted at a top end of each carrier 111 for receiving and subsequent delivering of an object. The cross-belt conveyor has an endless-loop conveying belt 105 which runs over two rollers that are separately positioned and extend in the conveying direction of the conveyor device 101. The top surface 103 of the cross-belt conveying belt 105 forms a rectangular support surface. An electric motor drives one of the cross-belt rollers in such a manner that the support surface 103 of the cross-belt conveying belt 105 moves in the direction perpendicular to the transport direction toward a predetermined delivery station. Each carrier 111 is supported and guided by means of the wheels 116 at its lower end section on left-hand side support / guide rail 114 and right-hand side support / guide rail 115, which determine an endless track path, as schematically shown in Fig. 2. According to the invention said endless track path may have both left curved sections 201 and right curved sections 202, as well as straight sections 203. As shown in Fig. 2, the hingeable connection between the carriers 111 of the prior art as described above is designed such that it allows for the carriers 111 with the support surfaces 103 to take both the left curved sections 201 and the right curved sections 202, wherein the carriers 111 may touch each other at the side of the inner curved sections, while leaving a gap between the carriers 111 at the side of the outer curved sections. In the straight sections 203 there is a gap between the carriers 111 on both sides. Now with reference to Fig. 3, according to the invention, the driving system and / or the connection means between the carriers 111 is designed such, that in the straight sections 203 of the endless track the distance between the carriers 111 is at least smaller than as shown in Fig. 2, and as shown in Fig. 3 in the preferred embodiment there is no distance between the carriers 111 in the straight sections 203 at all. Thereby in practice the capacity of the sorter can be increased by approximately 14%. According to the embodiment of Figs. 4A-C, each carrier 111 is arranged to contact and push the adjacent carrier at its front side 112. In the left curved sections 201 the carriers contact and push each other at the left-side and in the right curved sections 202 the carriers contact and push each other at the right-hand side. In the straight sections 203 the carriers 111 contact and push each other at both sides. To make contact, each carrier 111 is provided with resilient bumpers 401 at the right-hand side and the left-hand side. The bumpers 401 are deformable by the force of the contact between the carriers 111 and act as shock absorbers. The driving unit to drive the carriers 111 forward may for instance comprise a driven wheel or a gear wheel engageable with a friction surface or a toothed rack on the carriers, or may comprise a linear motor. One or more driving units may drive the carriers 111 forward at one or more driving locations along the endless track, such that the driven carrier 111 at said driving locations will push the carriers 111 in front of it forward. The driving means may also comprise a distributed driving means, such as a linear motor, distributed along substantially the entire length of the endless track, or at least along the straight section 203, such that substantially all of the carriers 111 are driven at once. According to the embodiment as shown in Figs. 5A-C, the carriers 111 are mutually connected by releasable connection means at their left-hand side and their right-hand side. The connection means on each side may comprise a latch 501 on the front side 112 of the carrier 111, which latch 501 may be a lever which is pivotable around a vertical shaft 510, and which is provided with a hook 502 on one outer end and a pin or wheel 503 on the other outer end. The hook 502 engages a pin 504 on the rear side 113 of the adjacent carrier 111. The latch 501 is spring loaded such that the latch automatically locks. An unlocking guide surface 505 is provided on the respective rail 114, 115 at the location of the start of the outer curved sections, which guide surface 505 engages the pin or rotating wheel 503 of the latch of each passing carrier, such that it forces to rotate the lever and release the hook 502 from the pin 504, thereby releasing the connection between the carriers 111 at the side of the outer curved sections. Since the latch 501 is spring loaded the latch 501 automatically locks and re-establishes the respective connection when the carriers 111 enters the straight sections 203 of the endless track. According to the embodiment as shown in Figs. 6A-D, the carriers 111 are mutually connected by releasable connection means at their centre, between the left-hand side and the right-hand side. The connection between the carriers 111 is provided by a sliding rod 611, which is fixedly connected in longitudinal direction to the front side 112 of each carrier 111, and which extend through, a slider ball joint 612 in an upright wall 613 at the rear side 113 of the adjacent carrier 111. The rod 611 is allowed to slide through said ball joint 612 in the longitudinal direction. The outer end of the rod 611 is provided with a widened stopper 614 which abuts against the inner side of the slider ball joint 612, when the rod 611 is pulled backwards through the slider ball joint 612 relative to the wall 613, as shown in Fig. 6D. The outer end of the rod 611 is furthermore provided with a pin 604, for engagement by a hook 602. The connection means furthermore may comprise a latch 601 at the centre of the carrier 111, which latch 601 may be a lever which is pivotable around a horizontal shaft 610, and which is provided with a hook 602 on one outer end and a pin or wheel 603 on the other outer end. The hook 602 engages the pin 604 on the outer end of the rod 611 of the adjacent carrier 111. The latch 601 is spring loaded such that the latch automatically locks. An unlocking guide surface 605 is fixed between the rails 114, 115 at the location of the start of the curved sections, which guide surface 605 engages the pin or wheel 603 of the latch of each passing carrier, such that it forces to rotate the lever and release the hook 602 from the pin 604, thereby releasing the fixed connection between the carriers 111. The connection between the carriers 111 is thereby constructed such, that if the connection is released by unlocking the latch 601, the distance between the carriers is allowed to increase from a minimum distance as shown in Fig. 6C to a maximum distance in the curved sections as shown in Fig. 6D, and the carriers 111 can pull the adjacent carrier 111 through the curved section. Since the latch 601 is spring loaded the latch 601 automatically locks and re-establishes the fixed connection with the rods 611 when the carriers 111 move along the straight sections 203 of the endless track. The invention has thus been described by means of preferred embodiments. It is to be understood, however, that this disclosure is merely illustrative. Various details of the structure and function were presented, but changes made therein, to the full extent extended by the general meaning of the terms in which the appended claims are expressed, are understood to be within the principle of the present invention. The description and drawings shall be used to interpret the claims. The claims should not be interpreted as meaning that the extent of the protection sought is to be understood as that defined by the strict, literal meaning of the wording used in the claims, the description and drawings being employed only for the purpose of resolving an ambiguity found in the claims. For the purpose of determining the extent of protection sought by the claims, due account shall be taken of any element which is equivalent to an element specified therein. An element is to be considered equivalent to an element specified in the claims at least if said element performs substantially the same function in substantially the same way to yield substantially the same result as the element specified in the claims.

Claims

C L A I M S 1. A conveyor device (101) comprising: an endless track which follows a track path in a transport direction, which track path comprises at least one straight section (203) and multiple curved sections in horizontal direction, wherein at least one of said curved sections forms a left curved section (201) and at least one other one of said curved sections forms a right curved section (202); a plurality of carriers (111) distributed in a closed loop along said track, wherein each carrier (111) comprises a rectangular support surface (103) for carrying one or more objects; driving means for moving said plurality of carriers (111) along said track; wherein said conveyor device (101) is configured such that: while moving along said at least one straight section (203) the distance between adjacent sides of two adjacent support surfaces (103) is dstraight; while moving along said left curved sections (201) on the right-hand side the distance between adjacent corners of said support surfaces (103) is xleftand on the left-hand side the distance betweenadjacent corners of said support surfaces (103) is yleft; andwhile moving along said right curved sections (202) on the right-hand side the distance between adjacent corners of said support surfaces (103) is xrightand on the left-hand side the distance betweenadjacent corners of said support surfaces (103) is yright; characterizedin that said conveyor device (101) is further configured such that while moving along said at least one straight section (203) the distance dstraightbetween adjacent sides of two adjacent support surfaces (103) is smaller than the average distance (yleft+ xleft) / 2 between the support surfaces (103) while moving along said left curved sections (201) and smaller than the average distance (xright+yright) / 2 between the support surfaces (103) while moving along saidright curved sections (202).

2. The conveyor device (101) according to claim 1, wherein saiddistances dstraight, yleft and xright between the support surfaces (103) aresubstantially equal.

3. The conveyor device (101) according to claim 1 or 2, wherein while moving along respectively said at least one straight section (203), said left curved sections (201) and said right curved sections (202) the carriers (111) are in contact with each other at respectively both sides, the left-hand side, and the right-hand side.

4. The conveyor device (101) according to any of the preceding claims, wherein each of said carriers (111) is arranged to contact and push the adjacent carrier (111) at its front side (112), wherein in the left curved sections (201) the carriers (111) contact and push each other at the left-side and in the right curved sections (202) the carriers (111) contact and push each other at the right-hand side.

5. The conveyor device (101) according to any of the preceding claims, wherein each carrier (111) is provided with bumpers (401) at the right hand side and the left hand side.

6. The conveyor device (101) according to any of the preceding claims, wherein the carriers (111) are mutually connected by releasable connection means at their left-hand side and their right-hand side, and said conveyor device (101) provided with means for releasing the connection between the carriers (111) at the left-hand side before or when the carrier (111) enters a right curved section (203), and for releasing the connection between the carriers (111) at the right-hand side before or when the carrier (111) enters a left curved section (203), and with means for re-establishing the respective connection after or when the carrier (111) leaves the respective curve.

7. The conveyor device (101) according to any of the preceding claims, wherein the carriers (111) are mutually connected by releasable connection means at their centre between the left-hand side and the right-hand side, wherein the connection between the carriers (111) is constructed such that if the releasable connection means is released, the distance between the carriers (111) is allowed to increase to a maximum distance, and with means for re-establishing the respective connection after or when the carrier (111) enters the straight section (203).

8. The conveyor device (101) according to any of the claims 6 or 7, wherein the releasable connection means comprise mechanical activator means for unlocking the respective connection at or before the start of each respective curve.

9. The conveyor device (101) according to any of the preceding claims, wherein said releasable connection means comprise a latch mechanism with a latch to establish said connection and said mechanical activator means comprise a guide surface located along the endless track which pushes against the latch when the carrier (111) passes said guide surface in order to unlock the latch and release said connection.

10. The conveyor device (101) according to claim 9, wherein said latch is spring loaded such that the latch automatically locks and re-establishes the respective connection when the carriers (111) move along the straight sections (203) of the endless track.

11. The conveyor device (101) according to any of the preceding claims, wherein said support surfaces (103) are formed by top surfaces (103) of a cross-belt (105) conveyor.

12. The conveyor device (101) according to any of the preceding claims, wherein the conveyor device (101) is a sorter device (101).

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