Singulation mechanism

Information

  • Patent Grant
  • 6575450
  • Patent Number
    6,575,450
  • Date Filed
    Tuesday, January 30, 2001
    23 years ago
  • Date Issued
    Tuesday, June 10, 2003
    21 years ago
Abstract
An improved singulation mechanism is provided for flat articles having significant variations in size, thickness and weight, which mechanism utilizes at least two vacuum chambers positioned behind a moving perforated to feed the articles and selectively controls at least one of pressure and flow for at least one of the chambers to facilitate the feeding of heavier articles, while inhibiting bleed through doubles for lighter articles. A mechanism may be provided which provides a puff of air to at least one of the chambers at the end of the operation thereof to reduce the feeding of doubles and a bent fence may be suitably positioned to both facilitate feeding of shorter articles and to facilitate proper initial alignment of the articles.
Description




FIELD OF THE INVENTION




This invention relates to handling and processing systems for mixed mail and related articles, and more particularly to a singulation mechanism for use in such systems which facilitate the handling of articles having significant variation in size, thickness and weight.




BACKGROUND OF THE INVENTION




Mixed mail received at a post office or other location must be sorted and/or otherwise processed so as to be directable to a desired location. To accomplish this function, random items of incoming mail are typically stacked, either manually or otherwise, for feeding to a first mechanism which singulates the mail so that only a single piece of such mail, which is properly oriented and spaced, is passed on to the sorting or other processing mechanism of a mail handling system.




While many mechanisms currently on the market do an adequate job of singulating certain types of mail, increasing demands are being placed on such systems, both as to the ranges in size, thickness and weight of the mail pieces to be handled and as to the speed at which such systems are to operate, while still maintaining high controllability on the outputted mail pieces, a low jam rate, low damage rate and substantial elimination of doubles passing into the sorting mechanism. For example, a specification for mail pieces to be handled in such a high performance system might include pieces ranging in thickness from 0.007″ to 1.25″, pieces ranging in weight from 0.03 oz to 6.0 lbs., and pieces ranging in size from 3.5×″5.0″ or 4.0×″4.0″ to 15″×15″. These variations in thickness, weight and size must be handled without sacrificing throughput, which may be up to approximately 14,500 mail pieces per hour, although this maximum rate may vary somewhat with the size of the pieces being processed, and preferably with an ability to control this rate. Further while the requirements discussed above are particularly applicable to mail handling systems, they can also arise in handling systems for packages and/or other generally flat articles.




A singulation mechanism designed to meet these specifications is taught in co-pending application Ser. No. 09/411,961, filed Oct. 4, 1999, entitled “Singulation Mechanism” and assigned to the assignee of this application. The subject matter of this co-pending application is incorporated herein by reference. The system of the prior application, which is shown in attached

FIG. 1A

, includes a singulation station


14


which receives a stack of mail or other appropriate flat articles


62


, which articles contact a guide wall


32


on their leading edge side, and feeds such articles, one at a time, to a takeaway mechanism


16


. Singulation station


14


includes a head against which articles


62


are pressed with a controlled pressure by mechanisms not shown in the Figure. The singulation head includes a selectively perforated belt


34


driven by rollers


50


A-


50


E so as to pass in direction


38


over a pair of vacuum chambers V


1


, V


2


, chamber V


1


being under a trailing side of each article


62


, and chamber V


2


being under a leading side of each article. A first sensor FL


1


detects articles as they leave singulation station


14


, and a second sensor FL


2


senses articles as they reach a pinch roller mechanism


52


of takeaway mechanism


16


.




In operation, vacuum chamber V


1


is first operated, as shown in

FIG. 1B

, to pull a trailing side of the article


16


in contact with belt


34


against the portion of belt


34


over the V


1


chamber. Since belt


34


has a very low friction surface, only the portion of the belt over the V


1


chamber engages a leading article


62


of the stack and causes the article to move with belt


34


in direction


38


. The distance between the leading edge of chamber V


1


and sensor FL


1


is such that the leading edge of even the smallest article


62


will reach FL


1


before the trailing edge of the article is no longer over chamber V


1


. When the leading edge of the article is detected by sensor FL


1


, suitable controls are operative to turn off chamber V


1


and to at the same time apply vacuum pressure to chamber V


2


. The turning off of vacuum pressure from chamber V


1


prevents chamber V


1


from feeding the next article in the stack, thus preventing the feeding of doubles, and the energization of chamber V


2


causes belt


34


to engage the trailing portion of the article being fed and to advance this article to takeaway station


16


. There is a slight deceleration of the article as chamber V


1


stops driving it and chamber V


2


is not fully operational. This deceleration, followed by a rapid acceleration as chamber V


2


kicks in, tends to shake loose any double adhering to the article being fed. Again, the distance between the leading end of chamber V


2


and sensor FL


2


/pinch roller


52


is less than the length of the shortest article being fed, this assuring that chamber V


2


can feed all articles


62


to be fed to pinch roller


52


where they are detected by detector FL


2


. When the article reaches roller


52


, its motion in direction


38


can be taken over by takeaway mechanism


16


, and chamber V


2


is therefore turned off as shown in FIG.


1


B.




While the singulation mechanism of

FIGS. 1A and 1B

provides far superior performance in meeting the specifications indicated above than any prior singulation mechanism, in practice, the large variations in size, thickness and weight for the articles being fed has made it difficult to provide sufficient vacuum to feed heavier articles to be fed, for example articles weighing 4-6 pounds, while not having so much vacuum that it bleeds through thinner articles, resulting in doubles being fed. It has therefore been very difficult to select the vacuum pressures for both chambers so as to be able to feed all articles, and in particular all mail items, within the above specification without also causing the feeding of an unacceptably high number of doubles.




A second problem with the device shown in

FIG. 1A

has been that, once vacuum is removed from chamber V


1


. the chamber in practice does not quickly return to atmospheric pressure as shown in FIG.


1


B. but continues to have some vacuum pressure even after chamber V


2


has been activated. This extended vacuum pressure in chamber V


1


can result in some lighter articles being pulled against belt


34


and held sufficiently so as to be fed by the belt while chamber V


2


is clearing the leading article, this also resulting in the potential feeding of a double.




Another potential problem is that, in the system of

FIG. 1A

, operator skill is the only assurance that all articles


62


are aligned against wall or fence


32


. This results in some articles not being properly aligned, leading to potential feeding errors. The system of

FIG. 1A

also has potential problems in feeding shorter articles.




A need therefore exists for an improved singulation mechanism which overcomes the problems indicated above, and which otherwise optimizes the singulation operation, particularly in high performance applications.




SUMMARY OF THE INVENTION




In accordance with the above, this invention provides a singulation head for use in a singulation mechanism for flat articles of varying size and weight, which mechanism includes a takeaway mechanism for articles exiting the head, detectors for selectively detecting article position for an article being singulated, and controls for the singulation mechanism. The singulation head includes a selectively perforated belt driven across the head at a selected rate, at least two vacuum chambers positioned behind the belt so as to apply vacuum thereto when energized, the chambers being successively positioned along the belt, with the controls energizing the chambers in a predetermined sequence in response to outputs from the detectors, and a feedback mechanism selectively controlling pressure and/or flow for at least one of the chambers to facilitate the feeding by the head to the takeaway mechanism of heavier articles to be singulated, while inhibiting bleedthrough doubles for lighter articles to be singulated.




The feed mechanism may include a metering plate between the chambers and the belt, the metering plate having openings therein over each chamber which permits sufficient pressure/flow to feed at least most of the articles with substantially no bleedthrough doubles. A mechanism may be provided for altering the metering plate for heavier articles to increase pressure/flow for at least one of the chambers sufficiently to feed such articles. The mechanism for altering may include second plate having larger openings formed therein over at least one of the chambers, the mechanism involving removing and replacing the metering plate, or the portion thereof over at least one of the chambers, using a second plate to cover or expose more or less of openings in the metering plate or other techniques.




The feed mechanism may include a portion of the controls operating in response to an indication from at least one of the detectors that an article has not been fed by the head for increasing the pressure and/or flow for at least one of the chambers to facilitate feeding of such article. For some embodiments, there is a chamber V


1


adjacent a selected portion of each article at the beginning of a feed operation and a chamber V


2


downstream from chamber V


1


, the portion of the controls increasing pressure and/or flow for at least chamber V


1


. For one embodiment, chamber V


1


is divided into a chamber V


1




a


and a chamber V


1




b


, chamber V


1




a


being between chambers V


1




b


and V


2


. For this embodiment, chamber V


1




a


, but not chamber V


1




b


, is normally operated to feed articles, and a portion of the controls operates at least chamber V


1




b


to facilitate feeding of an unfed article detected by said detectors. A portion of the controls may operate both chambers V


1




a


and V


1




b


at substantially the same time to feed the heavier article or may operate only chamber V


1




b


for this purpose. Particularly in the latter situation, chamber V


1




b


provides a greater pressure/flow than chamber V


1




a.






For various ones of the embodiments, a mechanism is included which provides a puff of air to a chamber, for example chamber V


1




a


where there is such a chamber, or chamber V


1


, at the end of each operation thereof. The puff of air may be sufficient to momentarily positively pressurize the chamber to which it is applied. The puff of air may be controlled by a puffer valve, with the same signal preferably triggering both chamber V


2


and the puffer valve.




The invention may also include a fence against which a leading edge of each article is to abut, one of the vacuum chambers, V


2


, being the leading-most one of the vacuum chambers, and the fence terminating at a distance from the belt slightly greater than the thickest article to be fed and at a point on the belt over a portion of chamber V


2


between a mid-region thereof and a trailing edge thereof. A metering plate may be provided over chamber V


2


, the metering plate having openings formed therein over substantially only the portion of chamber V


2


on the leading end side of the fence. The detectors may include a first detector located past a leading side of chamber V


2


, a second detector between the singulation head and the take-away mechanism and a third detector at the take-away mechanism. For some embodiments, the fence bends in the leading direction at a selected point behind the end thereof.




The invention also includes a singulation head for use in a singulation mechanism for flat articles of varying size and weight, which mechanism includes a takeaway mechanism for articles exiting the head, detectors for selectively detecting article position for articles being singulated and controls for the singulation mechanism, the singulation head including a selectively perforated belt driven across the head at a selected rate, at least two vacuum chambers positioned behind the belt so as to apply vacuum thereto when energized, the chambers being successively positioned along the belt, and the controls energizing the chambers in a predetermined sequence in response to outputs from the detectors, and a mechanism which provides a puff of air to at least one of the chambers at the end of each operation thereof. Such puff of air is preferably sufficient to momentarily positively pressurize the at least one chamber to which it is applied. As indicated above, the puff of air is preferably applied to chamber V


1


or to chamber V


1




a


where one of such chambers exists, and preferably controlled by a puffer valve triggered by the same trigger signal as chamber V


2


. The fence as described above may also be provided.




Finally, the invention may also include a singulation head for use in a singulation mechanism for flat articles of varying size and weight, which mechanism includes a take-away mechanism for articles exiting the head, detectors for selectively detecting article position for articles being singulated and controls for the singulation mechanism, the singulation head including a selectively perforated belt driven across the head at a selected rate. at least two vacuum chambers positioned behind the belt so as to apply vacuum thereto when energized, the chambers being successively positioned along the belt, and the controls energizing the chambers in a predetermined sequence in response to outputs from the detectors, and a fence against which a leading edge of each article is to abut, one of the vacuum chambers, V


2


, being the leading-most one of the vacuum chambers, the fence terminating at a distance from the belt slightly greater than a thickest article to be fed and at a point on the belt over a portion of chamber V


2


between a mid-region thereof and a trailing end thereof. This aspect of the invention may include the metering plate over V


2


having openings as described above, the three detectors described above and/or the fence bending in the leading direction at a selected point beyond the end thereof.




The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of preferred embodiments of the invention as illustrated in the accompanying drawings, the same reference numerals being used for common elements in the various drawings.











IN THE DRAWINGS





FIG. 1A

is a graphic top view representation of a prior art singulation head and takeaway mechanism;





FIG. 1B

is a diagram illustrating a timing/distance profile for mail under the influence of vacuum chambers V


1


, V


2


for the prior art singulation head shown in

FIG. 1A

;





FIG. 2A

is a graphic top view representation of an improved singulation head in accordance with at least one aspect of this invention and of the corresponding takeaway mechanism.





FIG. 2B

is a diagram illustrating a timing/distance profile for mail for the head of FIG.


2


A.





FIG. 2C

is a front view of a meter or face plate for vacuum chambers V


1


, V


2


of FIG.


2


A.





FIG. 3A

is a graphic top view of the singulation head portion of the system shown in

FIG. 2A

as modified in accordance with one embodiment of the invention;





FIGS. 3B and 3C

are diagrams illustrating the pressure profile for chamber V


1


for the embodiments of

FIG. 3A

without use of a puffer valve and with use of the valve, respectively:





FIG. 4A

is a front perspective view of a pair of vacuum chambers suitable for use in practicing the embodiment of

FIG. 2A

;





FIG. 4B

is a front perspective view of a meter plate which may be placed over the front of the vacuum chambers of

FIG. 4A

, particularly to move heavy articles;





FIG. 4C

is a front perspective view of a meter plate which may be placed over the vacuum chambers of

FIG. 4A

to move lighter articles.





FIG. 4D

is a front perspective view of a plate which may be slid over the meter plate of

FIG. 4B

when lighter articles are to be fed and selectively removed for the feeding of heavier articles;





FIG. 5

is a graphic top view representation of the singulation portion of the mechanism of

FIG. 2A

for an alternative embodiment of the invention; and




FIGS.


6


A and

FIG. 6B

are front perspective views of the vacuum chamber head of

FIG. 5

with the metering plate removed and with an illustrative metering plate in place, respectively.











DETAILED DESCRIPTION





FIG. 2A

illustrates an embodiment of the invention which differs from the embodiment of

FIG. 1A

in that alignment wall


32


has been replaced by an alignment wall


32


′ which is further back on singulation head


14


and is bent from a position which is substantially the same as that for the wall


32


to the position shown when adjacent to the singulation head with the and of the wall spaced from the head by a distance slightly greater than the thickest article


62


to be fed and over a point near the middle of chamber V


2


.

FIG. 2C

shows a metering plate


66


which may be placed over vacuum chambers V


1


and V


2


, with the openings


67


in the plate over vacuum chamber V


1


being toward the leading side of this vacuum chamber and the openings


68


over the vacuum chamber V


2


being located over the portion of chamber V


2


which is on the forward or leading side of this vacuum chamber and is over the portion of the chamber beyond wall


32


′. This embodiment of the invention also has an additional detector FL


5


which is located at the leading edge side of chamber V


2


, and thus generates an output when the leading end of the article being fed is fully over openings


68


. While for the embodiment shown in

FIG. 2A

, wall


32


′ is roughly half way or a little over half way back on chamber V


2


, depending on application, the wall may, for this embodiment of the invention, be positioned anywhere from over a mid-region of chamber V


2


to the junction between the two chambers.




The embodiment of

FIG. 2A

offers at least two advantages. First, articles


62


are typically manually aligned against wall


32


. While a skilled operator can normally do a good job of aligning the articles against this wall, inevitably, some articles, particularly smaller articles, will not be in registration against this wall. Smaller articles not being initially against the wall may prevent such articles from being properly fed and/or may result in vacuum also being applied to the article behind the forward most article, causing a double to be fed. The bent wall


32


′ moves articles


62


to in the rear or trailing direction as they advance to the singulation head, thus facilitating the alignment of all or substantially all of the articles against wall


32


′.




Moving wall


32


′ back and providing an additional sensor FL


5


also facilitates the feeding of smaller, shorter articles, assuring that these articles reach and are picked up by vacuum chamber V


2


and fed by this chamber to take-away mechanism


16


. Openings


68


being beyond wall


32


′ and vacuum chamber V


1


being on for a shorter duration, as can be seen from

FIG. 2B

, also reduces bleed through of vacuum for such smaller articles, thereby reducing doubles generation.





FIG. 3A

illustrates an embodiment of the invention which may be used with either the embodiment of

FIG. 1A

or the embodiment of

FIG. 2A

, and

FIGS. 4A-4C

illustrate variations on this embodiment. In

FIG. 3A

, it is seen that the embodiment of

FIGS. 1A

,


2


A has been modified by adding a puffer valve


70


which is connected between a line


72


leading to a positive pressure air source and a line


74


leading to the back of chamber V


1


. Referring to

FIG. 3B

, without puffer valve


70


, there is a time delay between article


62


being detected by detector FL


5


and the time vacuum pressure to chamber V


1


is cut off and, once vacuum is cut off, there is a further significant time delay before the chamber returns to atmospheric pressure. For an illustrative embodiment, this time is 29 ms. Puffer valve


70


is enabled in response to the same output from FL


5


which turns off vacuum to chamber V


1


and turns on vacuum to chamber V


2


, and is enabled for the same time interval as chamber V


2


. As shown in

FIG. 3C

, while the pressure in chamber V


1


initially goes negative, when the article being fed reaches sensor FL


5


, vacuum pressure to chamber V


1


is cut off after some time delay and, at the same time, puffer valve


70


is activated causing a puff or burst of pressurized air to be applied to chamber V


1


. This reduces the time required for chamber V


1


to return to atmospheric pressure, for example by about 50% to 15 ms for an illustrative embodiment. The duration of this puff is sufficient so that, as seen in

FIG. 3C

, chamber V


1


becomes slightly positively pressurized for a duration until the article reaches FL


2


. The more rapid removal of vacuum pressure from chamber V


1




a


s a result of the application of the air puff or burst thereto ensures that vacuum pressure is not applied to a trailing document, thus reducing the likelihood of a doubles being fed. To the extent some vacuum pressure had previously been applied to a trailing document to pull it against belt


34


, the positive pressurization of the V


1


chamber pushes the mail item or other article away from the belt, assuring that it does not move therewith, and further reducing the possibility of a doubles occurring, particularly for smaller articles. Puffer valve


70


thus eliminates one of the problems with the prior art system of

FIG. 1A

which has been discussed previously.




Referring to

FIGS. 4A-4D

. a first metering plate


78


is shown which may be screwed over the front of vacuum chambers V


1


and V


2


. which plate has relatively large openings


80


and


82


formed therein over chambers V


1


and V


2


. respectively. Since plate


78


permits substantial pressure and flow from the vacuum chambers to be applied to the openings in belt


34


, and thus to the articles in contact therewith. Plate


78


is thus useful for feeding heavier articles. However, the flow with plate


78


can be sufficient that vacuum pressure bleeds through thinner articles being singulated by the head, permitting vacuum to be applied to the article in the stack behind the article being fed. If this second article is also a relatively small and light article which can be fed by the vacuum pressure applied thereto, this can result in a double being fed. Therefore, it is preferable when lighter and thinner documents are being fed that metering plate


84


be screwed to the face of chambers V


1


and V


2


, this plate having relatively small openings


86


over the leading end of the V


1


chamber and larger openings


88


over the leading edge of chamber V


2


; however, the openings


88


are still substantially smaller than the openings


82


of plate


78


. The smaller openings of plate


84


restrict air flow, and thus restrict the vacuum applied to the article


62


adjacent belt


34


. The combination of the applied pressure and the openings


86


and


88


are selected to provide sufficient flow so that the head can feed most articles


62


which it is designed to feed; however, the flow through plate


84


is not sufficient to feed heavier articles. This means that an operator of the machine in which a head having plate


84


is being utilized must presort the mail or other articles to eliminate the heavier articles therefrom when head


84


is in place and must periodically unscrew and replace metering plate


84


with, for example, metering plate


78


to do one or more runs of the heavier articles.




While the entire plate


78


,


84


is replaced for the embodiment shown in

FIGS. 4A-4C

, this is not a limitation on the invention, and it may, for example, be necessary only to replace the rear portion of the metering plate over chamber V


1


rather than the entire plate in order to feed heavier articles. Further, to speed up the exchange operation, rather than screwing the metering plates


78


,


84


to the face of the vacuum chambers, it may be possible to snap or slide the plates into position to facilitate the exchanging thereof. Further, rather than fully replacing plate


78


, it may be possible to slide a plate


90


or pivot a plate


90


in place over plate


78


so that, for example, plate


90


covers half or two-thirds of the openings


82


to leave effective openings of the general size of openings


88


and openings


80


are covered to permit flow only through the much smaller openings


92


. With such an arrangement, it might be possible for plate


90


, for example, to normally be in place, permitting perhaps 80 percent or more of articles to be fed, and for plate


90


to be slid out of the way, wholly or partially, either by the operator or under automatic control, when the head is unable to feed an article applied thereto.




While the techniques described above overcome the problem of being able to feed both relatively heavy articles and relatively light and thin articles with the same system without an unacceptably high level of doubles, it can also result in a significant reduction in the throughput of the system and, for at least some of the techniques indicated above, requires greater operator involvement, which can further reduce throughput and/or increase costs of operation. Operating in this way is therefore not preferred, particularly in applications where a significant number of heavier articles are likely to be encountered.





FIG. 5

shows an alternative embodiment of the invention which facilitates automatic operation, thus permitting a wider range of article weights to be handled without an increase in the instance of doubles, and without a significant reduction in throughput. For this embodiment of the invention, instead of having two vacuum chambers V


1


and V


2


, three vacuum chambers V


1




a


, V


1




b


and V


2


are provided, with chamber V


1




a


being between chambers V


1




b


and V


2


and with chamber V


1




a


being smaller, and therefore providing less flow, than the other two chambers. As shown in

FIG. 6B

, the holes


95


in metering plate


94


over the vacuum chambers are also relatively small for chamber V


1




a


, further reducing flow for this chamber. Puffer valve


70


is provided for chamber V


1




a


. Each of the vacuum chambers is connected to a vacuum line


97


through a corresponding vacuum valve


96




1a


-


96




2


and a corresponding vacuum line


98




1a


-


98




2


to the corresponding vacuum chamber. Vacuum valves


96


are individually controlled from a suitable processor. Metering plate


94


has openings


100


in front of vacuum chamber V


1




b


which are slightly smaller than the openings


80


in metering plate


78


and has openings


88


in front of vacuum chamber V


2


which are substantially the same as openings


88


in metering plate


84


.




In operation, vacuum pressure followed by air pressure from puffer valve


70


is normally applied to valve V


1




a


, the pressure profile for this vacuum chamber being substantially the same as that for chamber V


1


in FIG.


3


C. At the same time that puffer valve


70


is operated, valve


96




1a


is closed and valve


96




2


is opened, causing vacuum to be applied to chamber V


2


to complete the feeding of the article. With the arrangement shown in

FIGS. 5 and 6

, and with valves V


1




a


and V


2


being operated as indicated, sufficient flow should be applied to feed most of a normal mixed mail input, perhaps 80% or more depending on the mix. When a heavier article is received at head


14


″, for which activation as shown of chambers V


1




a


and V


2


does not provide sufficient pressure and flow to feed, at the end of a selected maximum time period for activation of chamber V


1




a


, sensor FL


5


will indicate that the leading edge of the article has not advanced to this point. When this occurs, chamber V


1




b


is activated, either alone or in conjunction with chamber V


1




a


. Because of the larger size and capacity of chamber V


1




b


and the larger openings


100


in metering plate


94


in front of chamber V


1




b


, chamber V


1




b


provides sufficient flow to move the heaviest article which the system is designed to handle, particularly when operated in conjunction with chamber V


1




a


. When the article has advanced to FL


1


, chamber V


1




b


(and V


1




a


if still operated) is cut off and chamber V


2


energized to move the article to takeaway mechanism


16


in the manner previously described. While chamber V


1




a


could be operated in conjunction with chamber V


1




b


, the added flow provided by chamber V


1




a


may not be required for some applications. Further., while a puffer valve could be provided for chamber V


1




b


, since this chamber is operated only for larger heavier articles, any residual vacuum in this chamber is normally not a problem. However, in a truly mixed mail environment, where the mail item following a heavy item may be a small thin item, a puffer valve for chamber V


1




b


, while generally not required, may be included. Once the heavy article has been fed, the system returns to operating only with chambers V


1




a


and V


2


for the feeding of subsequent articles until the singulation mechanism


14


″ is again unable to feed the article pressed against belt


34


.




A system has thus been provided which permits optimum flow to be provided for each article being fed so that all articles within a relatively wide size and weight range may be successfully fed by the head, while maintaining the level of doubles passing from singulation head 14-14″ at an acceptably low level. While the invention has been particularly shown and described above with reference to several illustrative embodiments, and variations on these embodiments have been discussed, it is apparent that these various embodiments and modifications are being presented for purposes of illustration only and that further modifications may be made in the invention by one skilled in the art while still remaining within the spirit and scope of the invention, which is to be defined only by the appended claims.



Claims
  • 1. A singulation head for use in a singulation mechanism for flat articles of varying size and weight, which mechanism includes a takeaway mechanism for articles exiting the head, detectors for selectively detecting article position for an article being singulated and the singulation head including:a selectively perforated belt driven across said head at a selected rate, at least three vacuum chambers positioned behind said belt so as to apply vacuum thereto when energized, said chambers being successively positioned along said belt; wherein a first of the at least three vacuum chambers begins extraction of an article by applying a substantially light vacuum pressure thereto; a second of the at least three vacuum chambers continues extraction of the article in a controlled manner for presentation to downstream devices and, after detection of a successfully captured double, begins extraction of an article in that double; and a third of the at least three vacuum chambers provides additional necessary vacuum pressure to move heaviest of articles upon failure by the first chamber to move the heaviest of articles; and a feed mechanism selectively controlling at least one of pressure and flow for at least one of said chambers to facilitate the feeding by said head to said takeaway mechanism of heavier articles to be singulated while inhibiting bleed through doubles for lighter articles to be singulated.
  • 2. A singulation head as claimed in claim 1 wherein said feed mechanism includes a metering plate between said chambers and said belt, said metering plate having openings therein over each chamber which permit sufficient pressure/flow to feed at least most said articles with substantially no bleed through doubles.
  • 3. A singulation head as claimed in claim 2 wherein pressure/flow for at least one of said chambers is increased sufficiently to feed heavier articles.
  • 4. A singulation head as claimed in claim 3 wherein said mechanism for altering includes a second plate having larger openings formed therein over at least one of said chambers, the openings of the second plate being interchangeable with the corresponding openings of said metering plate.
  • 5. A singulation head for use in a singulation mechanism for flat articles of varying size and weight, which mechanism includes a takeaway mechanism for articles exiting the head, detectors for selectively detecting article position for an article being singulated and the singulation head including:a selectively perforated belt driven across said head at a selected rate, at least two vacuum chambers positioned behind said belt so as to apply vacuum thereto when energized, said chambers being successively positioned along said belt; and a feed mechanism selectively controlling at least one of pressure and flow for at least one of said chambers to facilitate the feeding by said head to said takeaway mechanism of heavier articles to be singulated while inhibiting bleed through doubles for lighter articles to be singulated, wherein the feed mechanism operates in response to an indication from at least one of said detectors that an article has not been fed by said head for increasing at least one of the pressure/flow for at least one of said chambers to facilitate feeding of said article, wherein there is a chamber V1 adjacent a selected portion of each article at the beginning of a feed operation, and a chamber V2 downstream from chamber V1, and wherein said feed mechanism increases pressure/flow for at least V1 and wherein chamber V1 is divided into a chamber V1a and a chamber V1b, chamber V1a being between chambers V1b and V2, wherein chamber V1a, but not chamber V1b, is normally operated to feed articles, and wherein feed mechanism operates at least chamber V1b to facilitate feeding of said article.
  • 6. A singulation head as claimed in claim 5 wherein said feed mechanism operates both chambers V1a and V1b at substantially the same time.
  • 7. A singulation head as claimed in claim 5 wherein chamber V1b provides greater pressure/flow than chamber V1a.
  • 8. A singulation head as claimed in claim 7 including a mechanism which provides a puff of air to chamber V1a at the end of each operation thereof.
  • 9. A singulation head as claimed in claim 8, wherein said puff of air is sufficient to momentarily positively pressurize chamber V1a.
  • 10. A singulation head as claimed in claim 8 wherein said puff of air is controlled from a puffer valve, and wherein a same signal triggers both chamber V2 and the puffer valve.
  • 11. A singulation head as claimed in claim 5 including a mechanism which provides a puff of air to chamber V1 at the end of each operation thereof.
  • 12. A singulation head as claimed in claim 11 wherein said puff of air is sufficient to momentarily positively pressurize chamber V1.
  • 13. A singulation head for use in a singulation mechanism for flat articles of varying size and weight, which mechanism includes a takeaway mechanism for articles exiting the head, detectors for selectively detecting article position for an article being singulated and the singulation head including:a selectively perforated belt driven across said head at a selected rate, at least two vacuum chambers positioned behind said belt so as to apply vacuum thereto when energized, said chambers being successively positioned along said belt; and a feed mechanism selectively controlling at least one of pressure and flow for at least one of said chambers to facilitate the feeding by said head to said takeaway mechanism of heavier articles to be singulated while inhibiting bleed through doubles for lighter articles to be singulated, further including a fence against which a leading edge of each article is to abut, one of said vacuum chambers, V2, being the leading-most one of said vacuum chambers, said fence terminating at a distance from said belt slightly greater than a thickest article to be fed and at a point on the belt over a portion of chamber V2 between a mid-region thereof and a trailing end thereof.
  • 14. A singulation head as claimed in claim 13, including a metering plate over chamber V2, said metering plate having openings formed therein over substantially only the portion of chamber V2 on the leading end side of said fence.
  • 15. A singulation head as claimed in claim 13 wherein said detectors include a first detector located past a leading side of chamber V2, a second detector between said singulation head and said take-away mechanism, and a third detector at said take-away mechanism.
  • 16. A singulation head as claimed in claim 13 wherein said fence bends in the leading direction at a selected point behind an end thereof.
  • 17. A singulation head for use in a singulation mechanism for flat articles of varying size and weight, which mechanism includes a takeaway mechanism for articles exiting the head, detectors for selectively detecting article position for articles being singulated and the singulation head including:a selectively perforated belt driven across said head at a selected rate; at least two vacuum chambers positioned behind said belt so as to apply vacuum thereto when energized, said chambers being successively positioned along said belt and a mechanism which provides a puff of air to at least one of said chambers at the end of each operation thereof.
  • 18. A singulation head as claimed in claim 17 wherein said puff of air is sufficient to momentarily positively pressurize said at least one chamber.
  • 19. A singulation head as claimed in claim 17 wherein there is a chamber V1 adjacent a selected portion of each article at the beginning of a feed operation, and a chamber V2 downstream from chamber V1, and wherein said mechanism provides a puff of air to at least chamber V1.
  • 20. A singulation head as claimed in claim 19 wherein V1 is divided into a chamber V1a and a chamber V1b, chamber V1a being between chambers V1b and V2, wherein chamber V1a, but not chamber V1b, is normally operated to feed articles, and wherein said mechanism provides a puff of air to at least chamber V1a.
  • 21. A singulation head as claimed in claim 20 wherein said puff of air is sufficient to momentarily positively pressurize chamber V1a.
  • 22. A singulation head as claimed in claim 21 wherein said puff of air is controlled from a puffer valve, and wherein a same signal triggers both chamber V2 and the puffer valve.
  • 23. A singulation head as claimed in claim 19 wherein said puff of air is sufficient to momentarily positively pressurize chamber V1.
  • 24. A singulation head as claimed in claim 17 including a fence against which a leading edge of each article is to abut, one of said vacuum chambers, V2, being the leading-most one of said vacuum chambers, said fence terminating at a distance from said belt slightly greater than a thickest article to be fed and at a point on the belt over a portion of chamber V2 between a mid-region thereof and a trailing end thereof.
  • 25. A singulation head as claimed in claim 24 including a metering plate over chamber V2, said metering plate having openings formed therein over substantially only the portion of chamber V2 on the leading end side of said fence.
  • 26. A singulation head as claimed in claim 24 wherein said detectors include a first detector located past a leading side of chamber V2, a second detector between said singulation head and said take-away mechanism, and a third detector at said take-away mechanism.
  • 27. A singulation head as claimed in claim 24 wherein said fence bends in the leading direction at a selected point behind the end thereof.
  • 28. A singulation head for use in a singulation mechanism for flat articles of varying size and weight, which mechanism includes a takeaway mechanism for articles exiting the head, detectors for selectively detecting article position for articles being singulated and the singulation head including:a selectively perforated belt driven across said head at a selected rate; at least two vacuum chambers positioned behind said belt so as to apply vacuum thereto when energized, said chambers being successively positioned along said belt and a fence against which a leading edge of each article is to abut, one of said vacuum chambers, V2, being the leading-most one of said vacuum chambers, said fence terminating at a distance from said belt slightly greater than a thickest article to be fed and at a point on the belt over a portion of chamber V2 between a mid-region thereof and a trailing end thereof.
  • 29. A singulation head as claimed in claim 28 including a metering plate over chamber V2, said metering plate having openings formed therein over substantially only the portion of chamber V2 on the leading end side of said fence.
  • 30. A singulation head as claimed in claim 28 wherein said detectors include a first detector located past a leading side of chamber V2, a second detector between said singulation head and said take-away mechanism, and a third detector at said take-away mechanism.
  • 31. A singulation head as claimed in claim 28 wherein said fence bends in the leading direction at a selected point behind the end thereof.
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