Belt conveyor and method of converting a roller conveyor to a belt conveyor, and retrofit kit |
|||||||
申请号 | US11651810 | 申请日 | 2007-01-10 | 公开(公告)号 | US07467708B2 | 公开(公告)日 | 2008-12-23 |
申请人 | Michael Thane McGettigan; David H. Cotter; Kenneth J. Kooistra; Curtis E. LeMay; | 发明人 | Michael Thane McGettigan; David H. Cotter; Kenneth J. Kooistra; Curtis E. LeMay; | ||||
摘要 | A belt conveyor includes spaced-apart opposite sidewalls and at least two rollers positioned along and between the sidewalls defining a zone in which two of the rollers are end rollers located at opposite ends of the zone. A continuous conveying belt is reeved around the rollers and defines a conveying surface between the sidewalls. At least one of the rollers is a driven roller to drive the conveying belt and move articles along the belt conveyor. The conveying belt is initially stretched lengthwise at least 0.75 percent when it is reeved around the rollers. The conveying belt is tracked around the rollers, without a take up device, by engaging with the rollers. End rollers are mounted to axles, each axle extending through and protruding from both sidewalls. Axle retainers may receive the ends the end roller axles and connect the axle ends to their respective sidewalls. The rollers may be driven in response to an article sensor that senses articles on the conveying belt, in order to convey or accumulate articles on the belt conveyor. The belt may be applied as a retrofit to an existing roller conveyor system, and the belt may be incorporated into a kit which may also include replacement end rollers and/or axle retainers for use at either end of a zone. | ||||||
权利要求 | The embodiments of the present invention in which an exclusive property or privilege is claimed are defined as follows: |
||||||
说明书全文 | The present application is a continuation in part of U.S. patent application, Ser. No. 11/504,509 filed Aug. 15, 2006 by Cotter et al., which is a continuation of U.S. patent application, Ser. No. 10/975,199, filed Oct. 27, 2004, now U.S. Pat. No. 7,093,709, which is a division of U.S. patent application, Ser. No. 10/358,690, filed Feb. 5, 2003, now U.S. Pat. No. 6,811,018, which claims priority of U.S. provisional applications, Ser. No. 60/356,045, filed Feb. 11, 2002, and Ser. No. 60/424,629, filed Nov. 7, 2002, which are all hereby incorporated herein by reference. The present invention relates generally to conveyors and, more particularly, to belt conveyors. It is known to provide zones of rollers along a roller conveyor, where each zone includes a driven roller and/or a plurality of idler or freely rotating rollers. The driven roller is typically operable to drive the idler rollers via a plurality of O-rings connecting each roller to an adjacent roller in the zone. Each zone may be independently operable to accumulate articles on a particular zone or zones, or to generally continuously convey articles along the zones of the roller conveyor. However, such roller conveyors are not suitable for certain applications where belt conveyors are desired, such as for conveying small articles which may fall between the rollers, for conveying damaged articles or articles with loose parts that may tend to become entangled with individual rollers, or for applications where a belt conveyor may be required or desired for other reasons. Also, due to relatively low friction between typical rollers and the articles being conveyed thereon, such roller conveyors are not suitable for providing accumulation of articles along an inclined or declined section of the roller conveyor. The present invention provides a belt conveyor that is suitable for continuously conveying articles along the conveyor or along segments or zones of the conveyor, and for accumulating articles on the individual segments or zones. The invention may provide for accumulation of articles on an incline or a decline if desired. The invention also provides a kit, and a method for installing the kit, to convert an existing roller conveyor to a belt conveyor. According to an aspect of the present invention, a belt conveyor includes spaced-apart opposite sidewalls and at least two rollers positioned along and between the sidewalls defining a zone in which two of the rollers are end rollers located at opposite ends of the zone. A continuous conveying belt is reeved around the rollers, the conveying belt defining a conveying surface between the sidewalls. At least one of the rollers is a driven roller to drive the conveying belt and move articles along the belt conveyor. The conveying belt is initially stretched lengthwise at least 0.75 percent when it is reeved around the rollers. The conveying belt is tracked around the rollers, without a take up device, by engaging with the rollers. According to another aspect, a belt conveyor's end rollers are mounted to axles, each axle extending through and protruding from both sidewalls. According to another aspect, a belt conveyor includes at least two axle retainers, each having at least one hole that receives an end of an axle, the axle retainer connecting the axle end to a respective sidewall. According to yet another aspect, a belt conveyor includes a contact assembly, a drive member, and a lifting device. The lifting device reciprocates to move the contact assembly and cause the drive member to engage at least one of the rollers and drive the conveying belt. According to still another aspect, a belt conveyor includes a motor-driven roller, such as a motorized roller, that drives the conveying belt. According to another aspect, a belt conveyor has two or more tandem zones, each including at least two rollers and a conveying belt. According to another aspect, each zone of the belt conveyor has at least one article sensor to detect articles in a zone, and a control to selectively drive at least one driven roller to drive the conveying belt. Each control may be operable to selectively accumulate articles in a zone. According to another aspect, a retrofit kit may be applied to a roller conveyor having at least two conveying rollers positioned between opposite sidewalls and forming at least one zone, in which the retrofit kit includes one or more conveying belts that are stretched at least 0.75 percent when installed over the rollers, the kit further including at least one replacement end roller having an axle longer than the spacing of the sidewalls between which the replacement end roller is to be installed, and at least two axle retainers to receive the ends of the axle at the sidewalls. According to another aspect, a method of converting a roller conveyor to a belt conveyor includes providing a roller conveyor with one or more zones, each zone including two or more conveying rollers positioned between opposite sidewalls, where two of the conveying rollers are end rollers located at opposite ends of each zone. The method further includes providing at least one continuous conveying belt, at least one replacement end roller, and at least two axle retainers. The rollers of a given zone are removed from the roller conveyor, after which one or both end rollers may be replaced by the replacement end rollers. The conveying belt may then be routed or reeved around the rollers, and stretched at least 0.75 percent as the rollers are positioned between the opposite sidewalls. The axle retainers are connected to the sidewalls at an end, or at both ends, of each zone. Once the rollers are in position with the conveying belt reeved around them, the axle retainers may be connected to the ends of the end roller axles. According to another aspect, a belt conveyor includes two or more zones that may be independently operable to allow for accumulation of articles at one or more zones along the belt conveyor. Each zone may include an article sensor that is operable to detect articles on the belt of the respective zone, whereby the conveying belt of each zone is operable in response to the sensor and the particular application of the zoned belt conveyor. Therefore, the present invention provides a belt conveyor which may have a plurality of independently operable zones or segments, each of which includes a continuous conveying belt, at least two rollers, and axle retainers. The zones may operate together as a generally continuously running belt conveyor or may operate individually as an accumulating conveyor with zone control and photo eyes or sensors. The invention may be practiced by applying a retrofit kit to an existing roller conveyor. The present invention thus provides a zone controlled belt conveyor which may operate in a similar manner as a zone controlled roller conveyor, but with a conveying belt reeved around the rollers. These and other objects, advantages, purposes, and features of the present invention will become apparent upon review of the following specification in conjunction with the drawings. Referring now specifically to the drawings and the illustrative embodiments depicted therein, a belt conveyor or belt accumulator 10, 110 includes one or more zones or segments 12, 112 positioned along and between opposite sidewalls or side frames 14, 114, and is operable to convey articles in a direction of conveyance indicated by the arrow marked “flow” ( Each belted zone 12, 112 may be independently operable to accumulate articles on the zone 12, 112 or to move articles in the flow direction onto a next, adjacent segment or zone or onto another conveyor, such as another belt conveyor, a roller conveyor, a slider bed, or the like, or any other means for receiving articles from a discharge end of the last zone or segment of the zoned belt conveyor 10, 110. Thus, belt conveyor 10, 110 may be used to convey small articles which might otherwise fall between the rollers, to convey damaged articles or articles with loose parts that may tend to become entangled with individual rollers, or for applications where a belt conveyor may be required or desired for other reasons such as transporting articles along inclines or declines. Belt conveyor 10, 110 may be manufactured from new components, or alternatively, belt conveyor 10, 110 may be constructed by modifying an existing roller conveyor such as that which is disclosed in U.S. Pat. No. 6,478,142, the disclosure of which is hereby incorporated herein by reference. Where it is desirable to modify a roller conveyor to be a belt conveyor, a retrofit kit 24 ( As noted above, retrofit kit 24 may include a conveying belt 20, replacement end rollers 26, and axle retainers 22. Replacement end rollers 26 and axle retainers 22 may improve the durability of the resulting belt conveyor when additional stresses are applied to any roller located at an end of a zone by the addition of the low modulus conveying belt 20, as will be discussed below. In the embodiment of In the embodiment of Optionally, other means for driving the conveying belt 20 may be implemented while remaining within the spirit and scope of the present invention. For example, motorized roller 34 ( In the embodiment of Conveying belt 20 may be a low modulus belt. In the illustrated embodiments, conveying belt 20 has a stretch capability or characteristic of at least approximately 1.5% stretch or more and may have a stretch capability or characteristic of approximately 3% to 5% stretch or more in its lengthwise direction. Conveying belt 20 may be initially stretched as it is reeved around rollers 16, 18, such that the belt has an initial stretch of approximately 0.75% or more in its lengthwise direction when positioned around rollers 16, 18, and may be initially stretched to have an initial stretch of approximately 1% or 1.5%. Conveying belt 20 provides a substantially greater amount of stretch over conventional conveyor belts, which typically may only provide approximately a 1% stretch characteristic or less, and typically may have an initial stretch of approximately 0.25% to 0.5% when reeved or positioned around the pulleys of a conventional belt conveyor. The low modulus characteristic of conveying belt 20 and the approximately 0.75% or more initial stretch of conveying belt 20 allows each zone 12, 112 of the belt conveyor 10, 110 to be operated with little or no take-up or adjustment being necessary to maintain the appropriate tension in conveying belt 20. However, such adjustment may be provided on belt conveyor 10, 110, without affecting the scope of the present invention. Conveying belt 20 is described in more detail in U.S. Pat. No. 6,811,018. Rollers 16, 116 may be any type of rollers, such as conventional, freely rotating rollers, such as the types commercially available from various sources, such as Dematic Corp. of Grand Rapids, Mich. End rollers 18, 118 and replacement end rollers 26 are preferably of a more robust construction to resist high belt tension loads, as will be described in more detail below. Although shown in the illustrations as having multiple rollers along each of zones 12, 112 one or more zones 12, 112 of the zoned belt conveyor 10, 110 of the present invention may include a support plate or slider bed (not shown) between the end rollers 18, 118, 26 to support conveying belt 20 without affecting the scope of the present invention. End rollers 18, 118 and replacement end rollers 26 ( Roller shell 44 may have one or more crowns or bumps 46 along roller shell 44 to assist in tracking belt 20 during operation of belt conveyor 10, 110. The use of crowns 46 to track belt 20 is disclosed in commonly assigned U.S. Pat. No. 6,811,018, the disclosure of which is hereby incorporated herein by reference. Crowns 46 may comprise one or more slightly larger diameter regions of the roller shell 44, such as two or three regions (or more or less depending on the length of the roller and the particular application) having, for example, approximately a 1-4 mm larger diameter than the diameter of the generally cylindrical roller shell 44, which may typically have a diameter of approximately 50 mm. Crowns 46 may be formed as part of the roller shell 44 or may comprise molded portions, such as molded polyurethane portions or the like, positioned along the roller shell 44, without affecting the scope of the present invention. Roller shell 44 may further incorporate circumferential grooves 38, as in Axles 40 preferably have a non-circular cross section, for example, a six-sided hex cross section, so that axles 40 may be gripped and held substantially stationary during operation of the belt conveyor 10, 110. Sidewalls 14, 114 have a plurality of sidewall apertures or holes 48 ( Additional support may be provided to end rollers 18, 118 or replacement end rollers 26 by connecting the rollers' axles 40 to axle retainers 22, which may themselves be connected to sidewalls 14, 114 ( Each clamping aperture 54 may be partly bounded by movable adjustment block 56, which is located at least partially in a channel 60 in base plate 52. Adjustment block 56 may have a recession 62 facing the center of clamping aperture 54, the recession 62 being shaped to receive an end portion of axle 40. Channel 60 may have an angled side surface 64 against which a portion of adjustment block 56 rests, the angled side surface 64 being angled to deflect adjustment block 56 toward the center of clamping aperture 54 by bolt 58, to grip axle 40 when bolt 58 is tightened. By tightening bolt 58 and thus urging adjustment block 56 toward the center of clamping aperture 54 until adjustment block 56 is tight against axle 40, axle 40 is held stationary during conveyor operation. Other embodiments of axle retainers may be found in commonly assigned U.S. patent application, Ser. No. 11/159,796 filed Jun. 23, 2005 by Cotter, et al., which is hereby incorporated herein by reference. Axle retainer 22 may be connected to sidewall 14, 114 such as with at least one bolt 66 ( Each zone 12, 112 of conveyor 10, 110 may include a photo eye or article sensor 70 ( Accordingly, belt conveyor 10, 110 may transport articles or accumulate and transport articles in response to article sensor 70 that detects the presence of articles in a given zone 12, 112 or in response to one or more other control inputs. Conveying belt 20 is driven by one or more rollers (16, 18, 116, 118, 26, 34) around which conveying belt 20 is reeved. One or more of rollers 16, 18, 26 may be driven by drive member 28 that is selectively moved into contact with a lower portion of rollers 16, 18, 26 ( Retrofit kit 24 may be installed on an existing roller conveyor by first at least partly removing the rollers from the zone, optionally replacing two of rollers 16, 116 with replacement end rollers 26, stretching and reeving conveying belt 20 around the rollers (16, 18, 116, 118, 26, 34), and by optionally installing axle retainers 22 at each end of the axles 40 corresponding to each end roller 18, 118, 26. The lift devices 30 ( Though in the embodiment of Therefore, the segmented or zoned belt conveyor of the present invention provides a plurality of independently operable zones which may operate together as a generally continuously running belt conveyor or may operate individually as an accumulating conveyor with zone control and photo eyes. The present invention thus provides a zone controlled belt conveyor which may operate in a similar manner as a zone controlled roller conveyor, but with a continuous conveying belt around the rollers rather than multiple O-rings or the like connecting the rollers to a motor-driven roller in each zone. Retrofit kit 24 may be installed on a roller conveyor by removing the rollers (16, 116, 18, 118, 34) of a given zone 12, 112, reeving or routing conveying belt 20 around the previously removed rollers and stretching the conveying belt 20 while reinstalling the rollers (16, 116, 18, 118, 34). Axle retainers 22 may be connected to axles 40 and sidewalls 14, 114 at each end of each zone 12, 112 during installation of retrofit kit 24. Replacement end rollers 26 may be installed after removing the rollers to be replaced, and before stretching the conveying belt 20 around the rollers. Changes and modifications in the specifically described embodiments may be carried out without departing from the principles of the present invention, which is intended to be limited only by the scope of the appended claims, as interpreted according to the principles of patent law. |