This disclosure relates to parts feeders for sorting parts and systems and methods therefor.
In a base implementation, step feeders for sorting and/or selecting parts consist of few basic components. A hopper which stores the parts prior to sorting. A lift to raise the parts to a linear conveyance system. A fixed mechanical track specific to the part, is used to singulate the parts. Any parts which do not align or are stacked are then recycled back to the hopper, typically through a fixed reject escarpment. To change the feeder to select for a new part, the existing mechanical track must be removed and the replaced with a new mechanical track specific to the part being sorted.
In a base implementation, a more advanced vision enabled feeder has a hopper to store the parts, a lift to raise the parts to a conveyance system, and a camera system having a wide field of vision which, when a known part is recognized, utilizes a robot enabled pick and place mechanism, to pick up the selected part. The conveyor runs continuously to passively reject both good and bad (i.e. rejected) parts back into the hopper. To select for a different part, the ‘end of arm’ tooling would be replaced with one specific to the new part to be selected.
A need exists for a flexible, high feed rate, rapid change over, full inspection parts feeder of the type described herein.
It will be appreciated by those skilled in the art that other variations of the embodiments described below may also be practiced without departing from the scope of the invention. Further note, these embodiments, and other embodiments of the present invention will become more fully apparent from a review of the description and claims which follow.
In one embodiment, there is described a parts feeder assembly which includes a hopper for receiving parts or other objects, a fixed depth lift operatively connected to an end of the hopper for driving received parts toward a conveyer, wherein the lift is controlled by a motor which can determine by use of an encoder the top end position of parts on the conveyer, the speed with which the parts are raised by the lift and the rate of acceleration/deceleration. At the top end of the lift, parts to be sorted are placed on the conveyor. The conveyor is also controlled by a motor which can determine by use of an encoder both the position of parts on the conveyor as well as conveyer speed. In operation, parts drop from the lift into a staging or accumulation area on the conveyor. Pre-staging singulation of parts is accomplished using an adjustable flex crowder comprising substantially a crowder landing member, a flex crowder member comprised of a flexible material, and a singulator crowder member. The flex crowder functions to control the passage of parts of varying sizes and/or shapes along the conveyor. The crowder landing member is a walled member positioned substantially perpendicular to the upper surface of the conveyor, which acts as a back stop for parts raised from the lift onto the conveyor to ensure that these parts remain on the conveyor. The crowder landing member is positioned in the vicinity of the lift egress. The singulator crowder member is a walled member also positioned substantially perpendicular to the conveyor. The singulator crowder member is positioned downstream from the lift egress and functions to guide singulated parts along the conveyor for selection. Both the crowder landing member and the singulator crowder member are adapted for movement in a horizontal plane toward and away from the conveyor). A flex crowder member is disposed between the crowder landing member and the singulator crowder member for the purpose of linking these members together. The flex crowder member is composed of a flexible material and the placement and material composition of the flex crowder member allow the flex crowder member to slide and flex, and change in shape in relation to the length of the conveyor adjacent to the flex crowder member in response to the movement of the adjacent members of the flex crowder forward and away from the conveyor. In particular, the size, shape and flexibility of the flex crowder member 90 promotes the gradual acceleration of parts as they move along the conveyor, and a gradual deceleration. An angled destacker functions to deflect stacked parts while reducing the occurrence of parts jamming by variance of its pinch point angle. The destacker is an angled divergence plate moveably attached to the leading end of the singulator crowder member for the purposes of enabling movement of the destacker up and down in a vertical plane substantially perpendicular to the upper surface of the conveyor depending on the characteristics of the parts to be sorted. Parts are singulated as they pass along the conveyor from the area in the vicinity of the flex crowder member to the area of the conveyor in the vicinity of the singulator crowder member. Once parts are positioned on the moving conveyor in the vicinity of the singulator crowder member, the singulator crowder member is moveable to position parts in the field of view of a camera, which operates as part of a linked, computer implemented system to identify parts to be selected or rejected. When a non-compliant part is identified, the system transmits instructions to a processor associated with the at least one blower to activate and the at least one part removal apparatus (such as a blower or a combination of a plurality of blowers) in order to remove the part from the conveyor. A bumper or abutment is affixed on or near the leading edge of the singulator crowder member, wherein the lower edge of the bumper is in contact with, or is close to contact with, the upper surface of the conveyor. When the parts feeder is in operation, parts which come into contact with the bumper are forced away from the singulator crowder member, which in turn enables an at least one blower disposed downstream from the bumper to pick up additional venture effect air volume.
In the drawings, preferred embodiments of the invention are illustrated by way of example. It is to be expressly understood that the drawings are only for the purpose of illustration and as an aid to understanding and are not intended as a definition of the limits of the invention. The embodiments herein will be understood from the following description with reference to the drawings, in which:
In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of the components outlined in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. In particular, all terms used herein are used in accordance with their ordinary meanings unless the context or definition clearly indicates otherwise. Also, unless indicated otherwise except within the claims the use of “or” includes “and” and vice-versa. Non-limiting terms are not to be construed as limiting unless expressly stated or the context clearly indicates otherwise (for example, “including”, “having”, “characterized by” and “comprising” typically indicate “including without limitation”). Singular forms included in the claims such as “a”, “an” and “the” include the plural reference unless expressly stated or the context clearly indicates otherwise. Further, the stated features and/or configurations or embodiments thereof the suggested intent may be applied as seen fit to certain operating conditions or environments by one experienced in the field of art.
In an example embodiment, as shown in
At the top end of the lift 30, parts to be sorted (not shown) are placed on the conveyor 40. The conveyor 40 is also controlled by a motor 60 (or equivalent) which can determine by use of an encoder (not shown) both the position of parts on the conveyor 40 as well as conveyer speed. In the embodiment contemplated, the encoder is an electro-mechanical device which converts the angular position of the motor 60 into digital pulses. For example, if the encoder has 360 increments, each pulse would indicate 1 degree of rotation of the shaft (not shown) of the motor 50. By operation of the encoder, the parts feeder assembly 10 is able to synchronize the cycle of the lift 30 with the speed of the conveyor 40 such that parts on the conveyor 40 will clear the deposit of a new batch of parts being placed on the conveyor. If parts are placed on the conveyor 40 without clearing the preceding batch, excessive parts are rejected, and cycle time goes down. In contrast, when the preceding parts are cleared off, cycle time goes up as system capacity increases. Still referring to
The singulator crowder member 100 is a walled member also positioned substantially perpendicular to the conveyor 40. The singulator crowder member 100 is positioned downstream from the lift 30 egress and functions to guide singulated parts along the conveyor 40 for selection. The singulator crowder member 100 is also operatively connected to an at least one adjusting rod (or movement member) 110 affixed to the feeder assembly on the side of the singulator crowder member 100. In the embodiment shown in
It should also be mentioned that the singulator crowder member 100 can also be moved close to the edge of the conveyor 40 on the side of the conveyor 40 opposite the singulator crowder member 100 in order to force non-aligned parts moving on the conveyor 40 in the vicinity of the singulator crowder member 100 back into the hopper 20.
Once parts are positioned on the moving conveyor 40 in the vicinity of the singulator crowder member 100 (e.g. parts on the conveyor adjacent to member 100), the singulator crowder member 100 is moveable to position parts in the field of view of a camera 180, which camera 180 is positioned above the conveyor 40 in the vicinity of the singulator crowder member 100.
Referring to
As previously indicated, the flex crowder 120 functions to retain and guide parts as they move along the conveyor 40. On the conveyor 40 in the vicinity of the crowder landing member 80, the parts dropped onto the conveyor 40 from the lift 30 are positioned in the staging area 70 on the conveyor 40. An alternative view of the staging area 70 is depicted in
The flex crowder 120 feature reduces or eliminates the need to employ a feeder using lifts of varying depths and widths including feeders which utilize multiple lifts of different sizes And the flex crowder member 90 which is disposed between and connected to each of the members 80, 100 makes up any difference in alignment between members 80 and 100 and thereby allows for a smooth transition of parts from the crowder landing member 80 to the singulator crowder member 100. When the feeder 10 is in operation, as parts move on the conveyor 40 from a position in the vicinity of the crowder landing member 80 and past the flex crowder member 90 to the singulator crowder member 100, any stacked parts and/or crowded parts (i.e. parts positioned side-by-side) are diverted back to the hopper 20 to be recycled through the process again.
The base concept of a step feeder is to align or singulate the parts such that the parts can then be fed either into a fixed escarpment or positioned in the field of view of a vision system associated with the step feeder. The conventional lift is of a fixed with and parts not aligned initially fall off the lift back into the hopper. With this type of system, the staging area is fixed so that as the parts move along the conveyor, they are further aligned. For large parts and/or cylindrical parts a wider lift is needed. The system of the present invention uses a different approach. All parts (i.e. small, large and/or cylindrical) are raised by a lift of defined width. The flex crowder staging or accumulation area 70, can be adjusted to a position either close to the edge of the conveyor 40 or set back from the edge of the conveyor 40. If a part being staged needs to be tipped back into the hopper 20, then the crowder landing member 80 can be moved forward close to the edge of the conveyor 40, in a similar manner to using a lift of narrow depth—but rather than have the parts tip back into the hopper 20 because the lift is too narrow to support them, in the case of the present invention, the parts tip back into the hopper 20 since the staging or accumulation area 70 has been narrowed by movement of the crowder landing member 80. In contrast, when larger parts are to be selected, since the lift is already of a fixed, wide depth to accommodate larger sized parts, the staging area 70 can be set wider by moving the crowder landing member 80 further away from the edge of the conveyor 40.
An angled destacker, shown generally by reference numeral 130 functions to deflect stacked parts while reducing the occurrence of parts jamming by variance of its pinch point angle. In the embodiment shown in
As mentioned, parts are singulated as they pass along the conveyor 40 from the area in the vicinity of the flex crowder member 90 to the area of the conveyor in the vicinity of the singulator crowder member 100. In the flex crowder 120 embodiment shown in
As different parts have different shapes, sizes, heights and centers of gravity, the push point or blow off point of a given part will vary from the upper surface of the conveyor 40 to typically the mid-point from the bottom of the conveyor to the top of the part. For example, parts such as washers which lie very close to the conveyor 40 surface require a low blow off point close to the conveyor 40 surface. In contrast, mid-size parts such as a ¾ inch nut may require a blow off point above the base of the conveyor 40. To accommodate a wide variety of parts of various shapes and sizes, heights and centers of gravity, a multiple blow off manifold with multiple jet outlet locations (or blowers 150) is used. Setting the location of the blow off point(s) is as simple as removing set screws from the manifold for desired location(s) and placing in set screws for blocking individual blowers 150.
Since parts on a conveyor may be prone to rolling (including cylindrical-shaped parts), the parts feeder 10 of the present invention may be adapted to slightly tilt the parts feeder (or the conveyor 40 portion of the parts feeder) to create a slight incline (e.g. 1 degree, or 1 to 5 degrees) on the conveyor 40 as parts move from the staging area 70 through the singulation crowder member 100 zone of the conveyor 40. This allows for cylindrical parts to be stabilized while traveling through the camera 180 field of view on the conveyor 40, while also not impeding the part from being rejected.
Now referring to
The part continues to move along the conveyor 40, wherein the position of the part has now been located by the laser trigger sensor to identify the leading-edge trigger set point and the position of the part on the conveyor based on the encoder count readings. The encoder count readings may be transmitted from the encoder for processing as part of a computer implemented system, wherein key components of the system are in network communication with one another in order to produce a set out outputs. A processor may be employed to receive and analyze the encoder count readings and transmit instructions to the camera 180 to take an image of the part when the part reaches the focal area for the camera 180, on the conveyor 40. A computer associated with a memory having stored thereon a database of existing part images, can be employed to receive a transmission of the image in question and compare the image in question to the images in the database using a proprietary algorithm based on input from the network linked camera, laser trigger sensor, and conveyor encoder for the purpose of identifying a non-compliant part. When a non-compliant part is identified, the system transmits instructions to a processor associated with the at least one blower 150 to activate and the at least one blower 150 or a combination of a plurality of blowers in order to remove the part from the conveyor 40.
In the case where a part is identical dimensionally to another part but only distinguishable by color, then the algorithm is set up to compare multiple (2 or more) images to determine a non-compliant part. When a part is identical to another with all physical dimensions and distinguishable only by color or finish, multiple camera images are then considered in the algorithm.
The part continues to move along the conveyor, the position is still being reference based on the pulse counts provided by the conveyor encoder. The part would then reach the part reject location or blow off. If the algorithm has determined that the part is non-compliant, then the blow-off pulse is activated. Typically, and by default the program is set up for a single reject/blow off pulse and is activated in, or approximately in, the center location of the part. In some cases, multiple blow off pulses will be required. The location of the blow off may be determined not to be the part center and may be activated ahead or after the center of the part which can be located by the leading edge of the laser trigger point as well as the location based on the pulse count from the encoder associated with the conveyor motor.
The algorithm monitors parts as they pass under the camera 180. If after a set period of time where parts are no longer being sensed as present, the system interprets this as a jam. At this point the conveyor stops, the lift is deactivated and the conveyor cycles in reverse to remove parts from the conveyor and from the destacker. Once the cycle concludes, normal operation resumes.
Consider the following jam clearing examples. The first is based on a situation where the destacker 130 cannot clear multiple level parts. In this case the conveyor 40 would continue to run however no images would be recorded by the camera 180. If after a set period of time (e.g. fifteen seconds), the system would assume a jam and go into a jam recovery cycle, wherein the conveyor motor 60 would move in a reverse direction. The lift motor 50 moves the lift to a lower position and remains there for the cycle, and any parts jammed under the destacker 130 would travel back to the conveyor landing area adjacent to member 80 and be directed back into the hopper 20. While the conveyor 40 reverses the blow off pulses of the at least one blower 150, any parts that are on the discharge member of the conveyor are returned back into the hopper 20 to be recycled. If the jam has cleared, the parts traveling along the conveyor 40 will now trigger an escapement sensor 170 which would reset a jam cycle count to zero. If a jam is still present a jam cycle count would increase by one and the jam recovery cycle would repeat. This cycle will repeat for three times or until the jam cycle count reaches three. If after the third time a jam is still being detected, the system will shut down a wait for technically assistance. The system will not restart until the system is reset. The escapement sensor 170 functions to monitor parts as they are being discharged through the escapement (e.g. the end of the conveyor 40, or conveyor roll-off member). If the escapement sensor 170 remains activated typically for a period of fifteen seconds, if is considered that there is an issue at the discharge of the parts. This would not be considered a feeder problem but to moderate the feeder, the conveyor motor 60 and the lift motor 50 would stop until the issue is resolved and parts resume feeding.
At some point the current part being run requires a change over to a new part. When this happens, the hopper 20 may be empty, partially full or completely full. Feeders are typically emptied by either scooping or manually picking the parts out or by continuing to run the system and switching a form of gate mechanism. At times this gate mechanism is not easily or safely accessible. The feeder 10 of the present invention uses an empty hopper cycle, wherein a back gate 190 is removed and an empty bin cycle is initiated which has the lift 30 operate as normal but in this case the conveyor 40 is reversed. The parts are then discharged to an area which is typically not the production member. The feeder allows for a hopper empty cycle by opening the back gate 190 and reversing the conveyor 40 while the lift 30 continues to cycle.
The scope of this disclosure encompasses all changes, substitutions, variations, alterations, and modifications to the example embodiments described or illustrated herein that a person having ordinary skill in the art would comprehend. The scope of this disclosure is not limited to the example embodiments described or illustrated herein. Moreover, although this disclosure describes and illustrates respective embodiments herein as including particular components, elements, functions, operations, or steps, any of these embodiments may include any modification, combination or permutation of any of the components, elements, functions, operations, or steps described or illustrated anywhere herein that a person having ordinary skill in the art would comprehend. All such modifications, combinations and permutations are believed to be within the sphere and scope of the invention as defined by the claims appended hereto.