Abstract:
A sorting machine receives a bulk of workpieces or fasteners from a hopper unit into a feed station which align the fasteners into a single file for engagement to a transport system of an inspection station. Preferably, the transport system has a conveyor belt with a magnetic member disposed radially inward from the belt. The fasteners are preferably ferrous and thereby engage the conveyor belt via the magnetic field which penetrates the belt. The fasteners are thus carried along the transport system past a trigger sensor which sends a signal to a central controller to timely actuate a dimensional sensing apparatus which takes an image of the fastener and sends it to the central computer for dimensional analysis. If the fastener fails to meet pre-established guidelines the nonconforming fastener is ejected from the transport system via a reject mechanism. If the fastener conforms, it continues to move along the transport system, past a counter sensor and is then dropped off the conveyor belt of the transport system into a packaging station for ultimate delivery to the customer.

Description:
TECHNICAL FIELD  
         [0001]    The present invention relates to a workpiece sorting machine and more particularly to an automated workpiece sorting, dimensional inspection and segregation machine for fasteners.  
         BACKGROUND OF THE INVENTION  
         [0002]    With increasing world-wide competition in manufacturing, reducing production costs while maintaining, if not improving, quality of the manufactured workpiece is paramount. When the workpiece is manufactured in large quantities, unique challenges in the manufacturing process are presented. For instance, the manufacturing of a fastener or threaded bolt as the workpiece requires dimensional inspection of each bolt which may not be visible to the naked eye. Moreover, to accomplish inspection, the fasteners or bolts must be arranged in an orderly fashion.  
           [0003]    Fasteners which do not meet pre-established quality guidelines must also be segregated from the remaining fasteners which are ultimately counted and delivered to the customer. Preferably, and as a cost cutting measure, the segregated rejected fasteners are recycled.  
           [0004]    Within an assembly line operation, manual operator arrangement of hundreds, if not thousands, of fasteners is cost prohibitive. Likewise, manual inspection of many different types of workpieces or fasteners may lead to operator error, may not be possible due to sight limitations of the naked eye, or simply may not be possible due to the speed in which the fasteners pass along the assembly line.  
         SUMMARY OF THE INVENTION  
         [0005]    A sorting machine receives a bulk of workpieces or fasteners from a hopper unit into a feed station which align the fasteners into a single file for engagement to a transport system of an inspection station. Preferably, the transport system has a conveyor belt with a magnetic member disposed radially inward from the belt. The fasteners are preferably ferrous and thereby engage the conveyor belt via the magnetic field which penetrates the belt. The fasteners are thus carried along the transport system past a trigger sensor which sends a signal to a central controller to timely actuate a dimensional sensing apparatus which takes an image of the fastener and sends it to the central computer for dimensional analysis. If the fastener fails to meet pre-established guidelines the nonconforming fastener is ejected from the transport system via a reject mechanism. If the fastener conforms, it continues to move along the transport system, past a counter sensor and is then dropped off the conveyor belt of the transport system into a packaging station for ultimate delivery to the customer.  
           [0006]    Advantages of the present invention include an automated inspection and sorting machine capable of improving quality of a manufactured workpiece, reducing required manpower, increased speed and efficiency of manufacturing, and is a robust and relatively inexpensive and user friendly design. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]    The presently preferred embodiments of the invention are disclosed in the following description and in the accompanying drawings, wherein:  
         [0008]    [0008]FIG. 1 is a side view of a sorting machine of the present invention;  
         [0009]    [0009]FIG. 2 is a side view of a feeder station of the sorting machine;  
         [0010]    [0010]FIG. 3 is a top view of a vibratory bowl of the feeder station;  
         [0011]    [0011]FIG. 4 is a top view of a dual belt drive system of the feeder station showing a fastener being carried upon and between two parallel conveyor belts of the dual belt drive system;  
         [0012]    [0012]FIG. 5 is an end view of the dual belt drive system;  
         [0013]    [0013]FIG. 6 is an enlarged partial side view of the sorting machine illustrating the workpiece being transferred from the dual belt drive system to a transport system;  
         [0014]    [0014]FIG. 7 is a partial perspective view of the sorting machine illustrating suspended fasteners being transferred from the top side of the dual belt drive system to the bottom side of the transport system;  
         [0015]    [0015]FIG. 8 is a side view of an inspection station of the sorting machine having the transport system;  
         [0016]    [0016]FIG. 9 is a top view of the transport system;  
         [0017]    [0017]FIG. 10 is a fragmented side view of the workpiece dimensional sensing apparatus;  
         [0018]    [0018]FIG. 11 is a partial perspective view of the transport system illustrating a workpiece rejection assembly;  
         [0019]    [0019]FIG. 12 is a partial longitudinal cross section of a transport system illustrating a second embodiment of a workpiece rejection assembly of a sorting machine;  
         [0020]    [0020]FIG. 13 is a partial longitudinal cross section of a transport system illustrating a third embodiment of a workpiece rejection assembly of a sorting machine;  
         [0021]    [0021]FIG. 14 is a side view of a fourth embodiment of a transport system of a sorting machine wherein the workpieces arc carried on the top side of the transport system;  
         [0022]    [0022]FIG. 15 is a top view of a fifth embodiment of a feeder station of a sorting machine;  
         [0023]    [0023]FIG. 16 is a side view of a sixth embodiment of a sorting machine;  
         [0024]    [0024]FIG. 17 is a top view of the sixth embodiment of the sorting machine;  
         [0025]    [0025]FIG. 18 is top view of a dual roller conveyor of the sixth embodiment of the sorting machine; and  
         [0026]    [0026]FIG. 19 is a partial cross section of the sixth embodiment of the sorting machine taken along line  19 - 19  of FIG. 17. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0027]    Referring to FIGS.  1 - 3 , the present invention is a sorting machine  20  of workpieces  22 . The machine  20  inspects and segregates out non-conforming or defective workpieces  24  from conforming workpieces  26  which meet pre-established dimensional guidelines assuring or thus maintaining the quality of the product which is ultimately sent to the customer. The workpieces  22  are preferably metallic fasteners or any other metallic part which can be secured to a magnet and is manufactured in mass quantities. The fasteners  22  may include, for example, bolts or screws that generally have flat and enlarged head portions and unitary narrow, threaded portions. In general, once a batch of fasteners is manufactured, the fasteners within the batch are sorted so that non-conforming, malformed, or defective fasteners  24  can be removed from the batch and discarded. In this way, only the conforming, properly formed, and non-defective fasteners  26  are ultimately made available for sale to the public.  
         [0028]    More particularly, once manufactured, the un-inspected fasteners  22  are stored within a hopper or bulk dumpster unit  28  of the sorting machine  20  and are thus staged to be fed into a fastener feed station  30  located adjacent to the hopper unit  28 . The hopper unit  28  is preferably designed to vibrat, causing the fasteners  22  to loosely fall into the feed station  30 . The feed station  30  orientates and aligns each fastener  22  which are then fed into an inspection station  32  via a central controller or computer  34 . The inspection station  32  examines each fastener  22  for dimensional conformance and automatically discards the rejected or failed fasteners  24  into a rejected station or container  36 , and transports the conforming fasteners  26  into a packaging station  38  for counting, packaging, and ultimate delivery to the customer.  
         [0029]    The hopper unit  28  has a large hopper  40  which contains the staged fasteners  22  and a vibrating tray  42  disposed directly between an opening  44  at the bottom of the hopper  40  and a vibrating distribution or container assembly  46  of the feed station  30 . Disposed below and engaged directly to the bottom of the tray  42  is a vibrating mechanism  48  which activates via a limit switch  50  that measures the level of fasteners  22  contained within a cylindrical bowl  52  of the vibrating container assembly  46 . When the level of fasteners  22  contained within the bowl  52  reaches a pre-established level, the limit switch  50  causes the vibrating mechanism  48  of the tray  42  to deactivate, as best shown in FIG. 3. Without the tray vibration, the fasteners  22  cease to flow out of the hopper  40 . When the level of fasteners within the bowl  52  decrease to a lower limit, the limit switch  50  re-activates the vibrating mechanism  48  to replentish the fasteners within the bowl  52  of the container assembly  46 .  
         [0030]    The vibrating container assembly  46  of the feed station  30  has at least one vibrating mechanism  54  engaged rigidly to a base  56  of the feeder station  30  and which impacts a rigid projecting member  58  of the bowl  52  at a frequency of between sixty to one hundred and twenty hertz. Preferably, there are two vibrating mechanisms  54  for each bowl  52 . The bowl  52  is supported by a series of spring type supports or leaf springs  60  which extend upward from the base  56  and engage a substantially planar bottom  62  of the bowl  52 . The leaf springs  60  permit limited vibratory movement of the bowl  52 . The vibration of the bowl  52  causes the fasteners  22  to move upward along a spiraling shelf  64  which projects radially laterally inward from a substantially cylindrical wall  66  of the bowl  52 . The fasteners or bolts  22  move via the vibration radially outward through an opening carried by the bowl wall  66  and disposed near the top of the bowl, and onto a pair of guide rails  68  secured rigidly to the exterior of the bowl wall  66 . Transfer of the fasteners  22  from the shelf  64  to the guide rails  68  is also assisted by a continuous blast of compressed air emitted from a flexible tube  70  secured near the top of the bowl wall  66 .  
         [0031]    The guide rails  68  are disposed substantially tangential to the bowl wall  66  and project at an angle slightly downward therefrom. The two parallel guide rails  68  are sufficiently spaced laterally away from one another so that the longitudinal or threaded portion of the fasteners or bolts  22  extend substantially downward between the rails  68 . The radial or head portion of the bolts  22  has a diameter greater in length than the width between the two rails  68 . In this way, the bolts  22  do not pass downward through the rails, but are suspended from the rails  68  in a linear orderly fashion.  
         [0032]    Referring to FIGS.  2 - 5 , the vibration of the bowl  52  and thus the rigidly engaged rails  68 , and the angle of the rails, cause the bolts  22  to move in a suspended fashion along and between the rails and onto a substantially horizontal dual belt drive system  72  of the feed station  30 . Each conveyor belt  74  of the dual belt drive system  72  moves via a common variable speed motor  76  controlled by the central controller  34 . A downward facing annular surface of the head of each bolt  22  rests directly upon both conveyor belts  74 . The lateral distance between the belts  58  and between the substantially parallel rails  68  is adjustable to accommodate fasteners or bolts  22  of varying head and/or shank diameters.  
         [0033]    Referring to FIGS.  6 - 9 , slightly overlapping a distal end portion  78  of the dual belt drive system  72  is a transport system  80  of the inspection station  32 . The transport system  80  is preferably of a variable speed conveyor belt type, having a longitudinal magnetic member  82  disposed substantially horizontally and radially inward from a substantially horizontal conveyor belt  84  preferably made from polyurethane. The magnetic member  82  is directly adjacent to that portion of the belt  68  which faces generally downward, yet disposed slightly above the distal end portion  78  of the dual belt drive system  72  to permit vertical clearance for the head of the bolt  22 . Two screw-type height adjustors  85  are operatively engaged to the transport system  80  to adjust for this height difference to accommodate fasteners  22  having different head vertical heights.  
         [0034]    As consecutive suspended bolts  22  near the distal end portion  78 , the magnetic member  82  attracts the metallic properties of the bolt  22  through the conveyor belt  84  of the transport system  80 . The frictional relationship between the belt  84  and the top of the head of the bolt  22  cause the bolt to move with the belt  68  although the magnetic member  82  is held stationary. Similar to the dual belt drive system  72 , the bolts  22  are again held in a suspended fashion except now from the top of the head. The magnetic force of the member  82  is strong enough to overcome the force of gravity which would otherwise cause the bolt  22  to disengage and fall.  
         [0035]    The magnetic member  82  is generally continuous and is composed of a series of constant and/or electromagnets  86  aligned directly adjacent to one another in a linear fashion and along the length of the conveyor belt  84  opposite the fasteners or bolts  22 . The belt  84  is driven by a variable speed gear motor  87  being adjustable and controlled by the central controller  34 . Increasing the speed of the conveyor belt  84  will increase the distance between fasteners  22  suspending from the belt. A minimum of one half inch fastener to fastener separation is required for reliable sorting and inspection. As the fasteners  22  travel with the belt  84  of the transport system  80  they individual pass between an emitter and a receiver light beam of a trigger sensor  88  which is preferably of a photo or infrared design which sends a signal to the controller  34  that in-turn triggers a dimensional sensing apparatus  90  disposed immediately downstream of the sensor  88 . The dimensional image or signal is processed by the central controller  34 . If pre-established dimensions or guidelines for the fastener  22  are not met, the fastener  22  is labeled as a nonconforming fastener  24 . The controller  34  then signals a reject mechanism  92  engaged operatively to the transport system  80  immediately downstream of the dimensional sensing apparatus  90  to release or eject the nonconforming fastener  24  from the transport system  80 , thus allowing the fastener  24  to fall into a reject shoot  94  which guides the nonconforming fastener into the bin  36  for recycling. The timing of the reject mechanism  92  actuation is dictated by the speed of the conveyor belt  84 .  
         [0036]    Referring to FIGS. 8 and 11, the reject mechanism  92  is illustrated as a pivoting flipper mechanism having a rigid plate which pivots into the path of the nonconforming fastener  24  thereby physically knocking the fastener into the reject shoot  94 . The magnets  86  of the member  82 , located at the point where the flipper or reject mechanism  92  physically knocks off the nonconforming fasteners  22 , have a magnetic strength which is slightly weaker than the magnetic strength of the remaining magnets, yet strong enough to prevent the conforming fasteners  26  from falling into the reject shoot  94 . This difference in magnetic strength assists the flipper mechanism  92  in removing the nonconforming fasteners from the transport system  80 .  
         [0037]    In operation, the flipper or paddle mechanism  92  has a solenoid which is energized by the controller  34  to force air into one end of a linear actuator  95 . The air forces a cylinder arm on the actuator, with a flipper paddle  97  mounted at the end at an approximate forty-five degree angle, out. The fastener  24  is then diverted off to the side of the conveyor belt  84  and into the rejection bin  36 . The paddle  97  remains positioned across the conveyor belt  84  until a conforming fastener  26  is sensed by the inspection method being used. The inspection method will send an electrical signal back to the controller  34  and energize another solenoid (not shown), which will send an air blast to the opposite end of the linear actuator (not shown), which in-turn forces the arm and attached paddle  97  back into its “home” position, off to the side, parallel to the conveyor belt  84 . The flipper paddle  97  will remain in its “home” position until a non-conforming fastener  24  is sensed by the inspection method in use, and the flipper mechanism  92  will once again energize.  
         [0038]    Referring to FIG. 12, a second embodiment of a reject mechanism  92 ′ is illustrated wherein the flipper of the first embodiment and the weaker magnets  86  located near the flipper are replaced with an electromagnet controlled by the controller  34 . Thus, when a traveling nonconforming fastener  24  is orientated below the electromagnet reject mechanism  92 ′, the controller de-energizes the electromagnet and the nonconforming fastener  24  falls into the reject shoot  94 .  
         [0039]    Referring to FIG. 13, a third embodiment of a reject mechanism  92 ″ is illustrated wherein the electromagnet of the second embodiment which performs the reject function is replaced with a passive or polarized magnet  96  engaged to a vertical moving rod  98  of a pneumatic or electric solenoid  100  of the reject mechanism  92 ″. The solenoid  100  is controlled by the controller  34 . Actuation of the reject mechanism  92 ″ causes the rod  98  to retract upward into the solenoid  100  which moves the magnet  96  upward and away from the conveyor belt  84  and thus the non-conforming fastener  24 . The magnetic field exposed to the targeted fastener  24  thus becomes weak enough, via spatial distance, for the nonconforming fastener  24  to fall into the shoot  36 .  
         [0040]    Referring to FIG. 8, a counter sensor  102  provides the signal sent to the controller  34  to count the passing conforming fasteners  26  while they are still secured to the belt  84  of the transport system  80  and prior to their release into a conforming fastener chute  104  engaged to the end of the transport system  80 . The counter sensor  102  is mounted to the transport system  80  between the chute  104  and any one of the reject mechanisms  92 ,  92 ′,  92 ″. The conforming fasteners  26  are counted and fall into the chute  104 , one by one, and through an open gate  106  engaged pivotally to the chute, and into a packaging container or box  108  of the packaging station  38 . When a predetermined number of conforming fasteners  26  have fallen into the box  108 , the gate  106  is closed via the controller  34 , or manually by an operator, until the next box  108  is positioned under the chute  104 . During this period of time that the gate  106  is closed, the transport system  80  can continue to drop conforming fasteners  26  into the closed chute  104  for a limited period of time at which point the gate  106  must be manually reopened or automatically reopened upon a permit signal indicating the next consecutive box  108  of the packaging station  38  is properly positioned below the chute  104 . The counter sensor  102  is preferably of a photo or infrared sensor type.  
         [0041]    Referring to FIGS. 8 and 10, the dimensional sensing apparatus  90  is capable of measuring micron size dimensions and may be of a laser-type device, however, a photo or camera-type device is preferred and thus illustrated. The dimensional sensing apparatus  90  is capable of sensing a multitude of dimensions simultaneously and the controller is capable of processing the signals from the apparatus  90  all well within the time it takes any one fastener to travel from the trigger sensor  88  to the reject mechanism  92 . The aperture setting of a lens  110  and the shutter speed of a camera  112  of the sensing apparatus  90  are dictated by the surrounding light conditions and speed of the conveyor belt  94  of the transport system  80 . The multitude of dimensions that the camera  112  is capable of simultaneously capturing or imaging may include for instance if the fastener  22  is a bolt the following dimensions or conditions typically known within the trade of bolt manufacturing: head diameter, flange diameter, washer diameter, head height, bearing thickness, shoulder length, shoulder diameter, dog point diameter, dog point length, shank diameter, shank angle, major thread diameter, minor thread diameter, sealant presence, thread count, washer angle, inverted washer, and length under head. If the dimensional or pre-established condition requirements are not met, the nonconforming fastener  24  can be rejected as previously described.  
         [0042]    Referring to FIG. 10, the picture produced by the sensing apparatus  90  is established by using a planar back light  114  made up of a series of light emitting diodes which are on or energized continuously. Alternatively, a flashing back light or strobe synchronized with the traveling fastener  22  and triggered by the same trigger sensor  88  that triggers the camera  112  will also suffice. Regardless, the back light  114  is located in a substantially vertical position on one side of the transport system  80  just below the belt  84 . Located on the opposite side of the transport system  80  is a mirror  116  set at an approximate angle of forty five degrees, thus being orientated to direct the light from the back light  114  upward toward a telacentric lens  118  which eliminates distortion, through a mid-lens  120  and into the camera  112  of the sensing apparatus  90 . The camera  112  in conjunction with the lenses  120 ,  118  generate a two-sided profile of the fastener  22  passing through the sensing apparatus  90 . Located in front of the mirror is a fixed piece of metal (not shown) that is in view of the camera  112 . This piece of metal serves as a start point to aid in establishing part length measurement. In addition, the number of cameras and lenses used and the location of those cameras may vary based on the customer&#39;s inspection requirements.  
         [0043]    Referring to FIG. 14, a fourth embodiment of an inverted transport system  80 ′″ is illustrated. The fasteners  22  are carried on the top side of a conveyor belt  84 ′″ with their heads down resting upon the belt. In this embodiment, it is clear that the force of gravity will not assist in moving the rejected fasteners off the belt. Therefore, the preferred reject mechanism  92  is that of the flipper which physically knocks or punches the rejected fastener off the belt  84 ′″, as previously described. A dimensional sensing apparatus, not completely shown, has a light back light  114 ′″ disposed above the transport system  80 ′″ instead of below as in the first embodiment. The camera (not shown) is disposed on one side of the belt and the back light  114 ′″ is disposed opposite, on the other side of the belt. Because the dimensional sensing apparatus can be mounted substantially horizontal, the forty-five degree positioned mirror of the first embodiment is not required. The inverted transport system  80 ′″ is useful for fastener inspection applications where the fastener has an unusual shape or is not metallic or does not react to the magnetic field of a magnet element.  
         [0044]    Referring to FIG. 15, a fifth embodiment of a sorting machine  20 ″″ is illustrated which is similar to the first embodiment except that the feeder station  30 ″″ has two vibrating container assemblies  46 ″″ and two pairs of rails  68 ″″ substantially tangentially extend from each container assembly  46 ″″ at a V-shaped junction  122  for a total of four. Each pair of rails  68 ″″ feed fasteners  22  into a respective dual belt drive system  72 ″″ which in turn feeds the fasteners  22  to a respective transport system  80 ″″. The sorting machine  20 ″″ is particularly useful where manufacturing plant floor space is scarce.  
         [0045]    Referring to FIGS.  16 - 19 , a sixth embodiment of a sorting machine  20 ′″″ is illustrated. A series of roller assemblies  46 ′″″ of a feeder station  30 ′″″ replaces the vibrating container assembly  46  and rails  68  of the first embodiment. Each roller assembly  46 ′″″ delivers suspended fasteners  22  to a respective dual belt drive system  72 ′″″ which in turn feeds the suspended fasteners to a respective magnetic transport system  80 ′″″.  
         [0046]    Each roller assembly  46 ′″″ has a first elongated roller  124  and a second parallel elongated roller  126  which counter rotates in relation to the first roller  124  and is spaced laterally therefrom at a distance slightly greater than the shank or elongated portion of the fastener  22 . Similar to the first embodiment, the head of the fastener rides on each roller  124 ,  126 . The assembly  46 ′″″ is slightly angled thus causing the fasteners  22  to move away from a vibrating tray  42 ′″″ of a hopper unit  28 ′″″ and toward the respective dual belt drive system  72 ′″″. An inverted V-shaped baffle or fastener guide plate  128  extends longitudinally between each roller assembly  46 ′″″ to guide the fasteners  22  falling from the common or singular vibrating tray  42 ′″″ between the counter rotating rollers  124 ,  126 .  
         [0047]    Although the preferred embodiments of the present invention have been disclosed, various changes and modifications may be made thereto by one skilled in the art without departing from the scope and spirit of the invention as set forth in the appended claims. It is also understood that the terms used herein are merely descriptive, rather than limiting, and that various changes may be made without departing from the scope and spirit of the invention.