Roller conveyor

Abstract

Roller conveyor (1), comprising - a plurality of conveyor rollers (3), the conveyors rollers (3) form a conveying surface (Sc) contacting an object to be conveyed (9) during a conveying operation; - a plurality of drive connections (31) connecting adjacent conveyor rollers (3) - a plurality of tube area safety guards (32); wherein conveyor rollers (3) connected to each other by any of the drive connection (31) form a conveyor zone (2); wherein said tube area safety guards (32) each close a gap (g) in a tube area (TA) between two adjacent conveyor rollers (3); wherein a gap (g) in a tube area (TA) between conveyor rollers (3) connected to each other by a drive connection (31) is not closed by one of said tube area safety guards (32).

Description

[0001] Roller conveyor

[0002] Description

[0003] The invention refers to a roller conveyor.

[0004] EP 3 222 564 B1 discloses a conveyor for conveying an object from a start position to a target place. The conveyor comprises a plurality of zones into which the conveyor is divided, the object being conveyed across the zones; each of the zones comprising: a linear conveyor zone that linearly conveys the object; a conveying direction changing zone selecting a conveying direction of the object to send out the object in the selected conveying direction; a conveyance destination storage unit that is configured to store the conveyance destination information temporarily; an information receiving unit that is configured to receive the conveyance destination information from an upstream zone; and an information transmitting unit that is configured to transmit the conveyance destination information to a downstream zone. The conveyor transfers the conveyance destination information from the upstream zone to the downstream zone with the movement of the object across the zones.

[0005] US 1 1 ,597,604 B1 discloses a conveyor safety guard module configured to be inserted between adjacent rollers in motor driven roller conveyor systems and shield drive bands or belts coupled between the adjacent rollers so as to protect workers from having their work gloves, loose hair, loose clothing, etc. becoming entangled e g. in the Poly-V-belt. Within the present description, such guards are also referred to as the drive area safety guards. Other drive area safety guards for the same purpose are known from EP 3 699 113 A1 , US 7,882,944 B1 , US 2023 / 0102050 A1 or WO 2020 / 216783 A1 . European patent application EP23158862.5 discloses filler plates to be provided in the gaps between two adjacent rollers to prevent that a user’s finger can protrude into the gap.

[0006] It is an object of the present invention to provide an efficient way of designing and operating roller conveyors in a safe manner. The object is solved by a roller conveyor according to the main claim; embodiments are subject of the subclaims and the description.

[0007] The present invention bases on the finding, that not all gaps between rollers are to be considered as a possible position, where a finger can be pulled in. Analysis of different configurations came to the result, that the rollers may not pull the finger into the gaps, which is depending on the drive configuration of the adjacent rollers.

[0008] In particular in case, that two adjacent rollers are rotating synchronously in the same direction, there is no risk of being pulled into the gap. In case that two adjacent rollers are not driven synchronously in the same direction, there may be a risk that a finger may be pulled into the gap between them.

[0009] In case that the adjacent rollers are non-driven rollers; no risk for being pulled into the gaps remains.

[0010] The invention is described in more detail with the help of the figures; herein show

[0011] Fig. 1 a conventional basic conveyor zone in perspective view in two embodiments;

[0012] Fig. 2 a roller of a conveyor zone in top view;

[0013] Fig. 3 a conventional basic roller conveyor;

[0014] Fig. 4 schematic representations of different drive configurations between adjacent rollers in side view;

[0015] Fig. 5 a schematic representation of parts of a conventional roller conveyor in side view;

[0016] Fig. 6 a schematic representation of parts of another conventional roller conveyor in side view;

[0017] Fig. 7 a schematic representation of parts of an inventive roller conveyor in side view.

[0018] Figure 1 a, b each show an exemplary conveyor zone 2 of a roller conveyor, comprising several conveyor rollers 3 mounted on a common support frame 4. The conveyor rollers 3 are driven together by a common motor. For this purpose, one of the conveyor rollers 3 is designed as a motorized conveyor roller 3M. The motorized conveyor roller 3M is driven in particular by a three-phase motor arranged within the conveyor roller. Via one or more drive connections 31 , e.g. a drive belt, some conveyor rollers 3 of a conveyor zone 2 are drive- connected to each other and are jointly driven by the motorized conveyor roller 3M. An upper side of the rollers form a conveyor surface Sc, on which an object 9 is in particular linearly conveyed from an inlet I to an outlet O along a conveying direction d.

[0019] All rollers shown in the conveyor zone of figure 1a are driven rollers, since even the idler rollers are drive-connected to the motorized roller 3M via the drive connections 31. The drive connection 31 in particular comprises a drive belt, e.g. a Poly-V-belt.

[0020] In contrast thereto figure 1 b shows a slight modification of the embodiment in figure 1. Here the most downstream conveyor roller 3x is an idler roller which is not connected to any adjacent roller via a drive connection 31 . The conveyor roller 3x is a non-driven conveyor roller. According to the definition of a conveyor zone 2 within the present application the conveyor roller 3x is not a member of the conveyor zone 2; the dashed lines Z illustrates the border of the conveyor zone 2. Consequently the term “driven roller” refers to

[0021] - a motorized roller having an internal motor and

[0022] - an idler roller, which is drive-connected to a drive motor, in particular to a motorized roller, in particular by a Poly-V belt.

[0023] By means of a presence sensor 5, the presence of an object to be conveyed 9 arranged on the conveyor zone 2 can be determined as soon as the object 9 comes into the field of view of the sensor 5.

[0024] The motorized conveyor rollers 3M are each controlled by at least one or a plurality of local zone controllers 11 (figure 3). A local zone controller 11 can control the motorized conveyor rollers 3M of several conveyor zones 2. A plurality of local zone controllers 11 are arranged in a roller conveyor 1 , which communicate with each other via a bus connection 13.

[0025] Figure 2 shows details of rollers used within a conveyor zone 2. The roller, which may be a motorized roller 3M or an idler roller 3, has a roller tube 3T. The roller tubes 3T of the several rollers within one zone constitute the constitute the conveying surface Sc of said conveyor zone. Axially neighbored to the roller tube 3T is a roller drive section 3D, comprising means for connecting the roller to a Poly-V-belt or any other drive connection 31 .

[0026] When viewed in top view as in figure 2, the roller 3 is divided into a tube area TA, where the roller tube 3T is located and which contributes to the conveying surface Sc, and a drive area DA, where the drive section 3D is located. Accordingly, the conveyor zones 2 (figure 1) and a roller conveyor 1 (as described later with figure 3) are divided into said tube area TA and said drive area DA.

[0027] Figure 3 shows a basic roller conveyor 1 , comprising conveyor zones 2a..e as described previously . A plurality of local zone controllers 11 control the operation of the conveyor zones 2. A PLC 12 (programmable logic control) may be provided to control the overall operation of the roller conveyor 1 .

[0028] Scanners (not shown) may be arranged along the conveyor zones 2 and provide identification data relating to objects 9a..c passing the scanner in the zones. These identification data are sent via a bus connection 13 to the PLC 12. The PLC 12 has access to an object data base (not shown), which provides destination data based on the identification of the objects 9. Based on the acquired data the PLC 12 provides operation instructions to a local zone controller 11 , how to handle the object 9, i.e. to which of the outlets O said object 9 is to be conveyed.

[0029] Conventionally, there are two kinds of injury risks concerned with such conveyor zones: Risk 1 : a first risk in connection with drive connection 31 , in particular in relation with a Poly-V- belt. Here a user may get trapped between a Poly-V-belt and the drive section 3D of the roller 3. This risk occurs in the drive area DA. To avoid any injuries caused by the drive connections, in particular by a Poly-V-belt of said drive connections 31 , a drive area safety guard 7 is provided below the drive connection (see figure 3)within the drive area DA of a roller conveyor. Suitable drive area safety guards are known from US 11 ,597,604 B1 , EP 3 699 113 A1 , US 7,882,944 B1 or WO 2020 / 216783 A1 . Such a drive area safety guard 7 merely covers the area of the drive connection and protects only an area between roller, which are driven synchronously.

[0030] Risk 2: a second risk is that a finger f of a user may protrude into the gap between roller tubes 3T of two adjacent rollers 3, as shown in figures 1 and 2. This risk occurs in the tube area TA. It is known to prevent this by providing a filler plate in the tube area TA between two adjacent rollers 3 (as described with reference to figure 10 in European patent application EP23158862.5 (published after the application I priority date of the present application).

[0031] Figure 4 shows different drive configurations between two adjacent rollers 3a, 3b in a conventional roller conveyor, where the subject of here is focused on the above second risk within the tube area TA is. The configurations have been analyzed in more detail in view of their safety risks. The drive connections 31 are merely illustrated schematically so that it gets apparent, which rollers are driven synchronously and which rotate independent from each other.

[0032] Figure 4a shows a first configuration with two adjacent rollers 3a, 3b, which may be part of separate conveyor zones 2. Here a first roller 3a is a driven roller which is drive-connected to other rollers (not shown) of the respective conveyor zone 2. A second roller 3b adjacent to the first roller 3a is a driven roller as well, which is also drive-connected to other rollers (not shown) of another respective conveyor zone 2. In a certain situation, both rollers rotate in contrary directions of rotation R1 , R2. When a finger f of a user protrudes into the gap g within the tube area TA between the tube sections 3T of these neighboring rollers 3a, 3b, the finger f will be actively pulled (arrow P1 ) into the gap g within the tube area TA by the contrary rotating roller tubes 3T of said rollers 3a, 3b. This configuration is a critical configuration in terms of finger safety.

[0033] Figure 4b shows a second configuration with two adjacent rollers 3a, 3b, Here a first roller 3a is a driven roller which is drive-connected to other rollers (not shown) of the respective conveyor zone 2. A second roller 3b is a non-driven roller. In a certain situation, the first roller 3a may be driven in a first direction of rotation R1 , where the second roller 3b does not rotate at all. When a finger f of a user protrudes into the gap g within the tube area TA between the tube sections 3T of these neighboring rollers 3a, 3b, the finger will be actively pulled (arrow P1) into the gap g within the tube area TA by the rotating roller 3a. The second roller 3b will be passively set into a contrary rotation R2 (dashed line) by the finger f being stuck between the two rollers 3a, 3b which is increasing the pull-in effect. Even if the one of the adjacent rollers is a non-driven roller, this configuration is a critical configuration in terms of finger safety.

[0034] Figure 4c shows a third configuration with two adjacent rollers 3a, 3b. Here both rollers 3a, 3b are motor-driven rollers which are drive-connected to each other via a drive connection 31 .

[0035] The first roller 3a and the second roller 3b rotate always synchronously in the same direction of rotation R1 . When a finger f of a user protrudes into the gap g within the tube area TA between the tube sections 3T of these neighboring rollers 3a, 3b, the finger f will be actively pushed (arrow P2) out of the gap g by one of the roller, here roller 3b.

[0036] From the above description of figures 4a,b,c is gets apparent, that the safety risks in the drive area DA and the in the tube area TA diverge and are, strictly speaking, opposite to each other.

[0037] Where the first risk of getting trapped in the DA is given at rollers, which are connected to each other by a drive connection, the second risk is given at rollers which are - -contrary to that - not connected to each other by such a drive connection.

[0038] Figures 5 to 7 show in schematic representations the tube areas TA of different conveyor zones 2 arranged in a roller conveyor 1 , where the conveyor zone may be in main similar to the conveyor zone 2 according to figure 2. The roller conveyor 1 has a plurality of conveyor rollers 3a .. 3m, the axis of which are arranged parallel to each other.

[0039] All conveyor rollers 3 within one conveyor zone 2a, 2b, and 2d are drive-connected to each other with a drive connection 31 (the drive connections are merely illustrated schematically so that it get apparent, which rollers are driven synchronously). Consequently all rollers in the first, second and fourth zones 2a, 2b, 2d are driven rollers. The rollers 3i, 3j in the remaining third conveyor zone 2c are non-driven idler rollers, each of which are not drive-connected to another roller.

[0040] In the first conventional embodiment shown in figure 5 the gaps between the rollers 3 are not provided with a safety device. This is not a safe solution.

[0041] To provide a conventional safe solution in the second conventional embodiment shown in figure 6 all gaps between all rollers are provided with tube area safety guards 32 preventing the insertion of fingers into the gaps. Figure 7 shows a novel and inventive solution which provides the most cost efficient way of making the conventional roller conveyor 1 shown in figure 5 safe. Here the findings of figure 4 are taken into account. So merely those gaps are provided with a tube area safety guard 32, which constitute a real safety issue. That means, that merely the gaps

[0042] - left of the roller 3a,

[0043] - between the rollers 3d and 3e,

[0044] - between the rollers 3h and 3i,

[0045] - between the rollers 3j and 3k are protected with tube area safety guards 32.

[0046] The remaining gaps do not constitute safety issues and are therefore not provided with tube area safety guards 32. In the present examples this implies a cost reduction for the provision of tube area safety guards of about 70%.

[0047] List of reference signs

[0048] 1 Roller conveyor

[0049] 2 conveyor zone

[0050] 3 conveyor roller

[0051] 3M motor-driven conveyor roller

[0052] 3T roller tube

[0053] 3D roller drive section

[0054] 3E endcap

[0055] 3x non-driven roller

[0056] 31 drive connection

[0057] 32 tube area safety guard

[0058] 4 support frame

[0059] 5 presence sensor

[0060] 7 drive area safety guard

[0061] 9 object to be conveyed

[0062] 11 local zone controller

[0063] 12 PLC

[0064] 13 bus connection d conveying direction

[0065] I inlet

[0066] O outlet f finger g gap between two rollers

[0067] R direction of rotation

[0068] P arrow

[0069] Sc conveying surface

[0070] Z border of conveying zone

[0071] DA drive area

[0072] TA tube area

Claims

Claims1. Roller conveyor (1), comprising- a plurality of conveyor rollers (3), the conveyors rollers (3) form a conveying surface (Sc) contacting an object to be conveyed (9) during a conveying operation;- a plurality of drive connections (31) connecting adjacent conveyor rollers (3)- a plurality of tube area safety guards (32); wherein conveyor rollers (3) connected to each other by any of the drive connection(31) form a conveyor zone (2); wherein said tube area safety guards (32) each close a gap (g) in a tube area (TA) between two adjacent conveyor rollers (3); characterized in that a gap (g) in a tube area (TA) between conveyor rollers (3) connected to each other by a drive connection (31) is not closed by one of said tube area safety guards(32).

2. Roller conveyor (1) according to the preceding claim, characterized in that a gap (g) in a tube area (TA) between driven conveyor rollers (3) which are not connected to each other by a drive connection (31) is closed by one of said tube area safety guards (32).

3. Roller conveyor (1) according to any of the preceding claims, characterized in that a gap (g) between a driven conveyor roller and a non-driven conveyor roller is closed by one of said tube area safety guards (32).

4. Roller conveyor (1) according to any of the preceding claims, characterized in that a gap (g) between two non-driven conveyor rollers is not closed by one of said tube area safety guards (32).

5. Roller conveyor (1) according to any of the preceding claims, characterized inthat at least in one gap in a drive area (DA) between the drive sections (3D) of neighboring rollers (3) a drive area safety guard (7) is provided.

6. Roller conveyor (1) according to any of the preceding claims, characterized in that each conveyor roller (3) has a roller tube (3T) and a roller drive section (3D), in particular- wherein the roller drive section (3D) is located in a drive area (DA) of the roller conveyor (1),- wherein the roller tube (3T) is located at least within a tube area (TA),- wherein the tube area (TA) is located axially neighbored to and / or axially outside of the drive area (DA).

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