US3504909A

US3504909A - Apparatus for separating and individually discharging flat articles

Info

Publication number: US3504909A
Application number: US730283A
Authority: US
Inventors: Gisbert Burkhardt
Original assignee: Telefunken Patentverwertungs GmbH
Current assignee: Telefunken Patentverwertungs GmbH
Priority date: 1967-05-26
Filing date: 1968-05-20
Publication date: 1970-04-07
Anticipated expiration: 1987-04-07
Also published as: NL6807134A; FR1565292A; BE715639A; DE1561189B1; GB1216876A

Description

Apnl 7, 1970 1 G. BURKHARDT 3,504,909

APPARATUS FOR SEPARATING AND INDIVIDUALLY DISCHARGING FLAT ARTICLES Filed May 20, 1968 2 Sheets-Sheet 1 Fig.2

, Inventor.- G-isbevt ?ar6c 35; 2 Mau Hktornegs A ril 7, 1970 G. BURKHARDT 3,504,909 APPARATUS FOR SEPARATING AND INDIVIDUALLY DISGHARGING FLAT ARTICLES Filed May 20, 1968 2 Sheets-Sheet 2 mm mm B mm il II. M .8 E fi m w y m r Rm MNWJW a m? R 0% i 42 HHZOVneSS United States Patent O Int. (:1. B65h3/12, 3/46 US. Cl. 271-11 19 Claims ABSTRACT OF THE DISCLOSURE Apparatus for separating and discharging fiat articles from a stack. A first separating means is arranged near a second separating means. Conveying means having holding and driving mean-s conveys the articles from the first to the second separating means. interrogating means having first and second sensing and signalling means is provided at the second separating means for controlling the operation of the first separating means. Interrupting means at the first separating means responds to signals received from the interrogating means by preventing the top article in such stack from being conveyed. Such interrogating means sending such signal to the interrupting means only during a predetermined period of time and in response to predetermined conditions concurrently existing at the first and second sensing and signalling means which indicate the article accumulation at the second separating means.

BACKGROUND OF THE INVENTION The present invention relates to apparatus for separating and individually discharging flat articles, for ex ample letters which are accumulated in a stack. In particular, the apparatus is characterized by an arrangement where the output of a first separating means which receives the letters in a stack is connected to the input of a second separating means and a letter sensing system is provided at the second separating means which controls the operation of the first separating means in accordance with the number of letters accumulated in the second separating means.

When flat articles are separated errors frequently occur in the form of double discharges. The number of such errors occurring during any separating operation depends on several factors including the consistency of the article, the required speed with which the separation occurs, the sequence of article separation and the type and construction characteristics of the particular separating and discharging apparatus used. For instance, the number of errors which occur are relatively high, when the articles vary greatly in physical characteristics. This is the normal situation where mail shipments are concerned. In the case of mail shipments, it has been found that suction-operated separating means are generally more useful, whereas in the separation of articles having similar physical characteristics, it has been found that simple frictional separating means are quite adequate to keep the number of errors that occur at a minimum.

The German Patent No. 1,187,246, describes suction apparatus for separating flat articles from a stack. This apparatus is intended for use at a coding station in the mail separating art. The German patent describes an apparatus whereby articles are individually discharged into a reading position upon an appropriate signal being received. For such use, it is not necessary that error occurrences be kept to a minimum. The occurrence of "Ice errors, however, should be less in such apparatus than in mechanical separating apparatus where no suction means are used.

The German patent teaches an apparatus where two or more relatively simple separating devices or separators, each having higher error incidence than permissible, are arranged serially with respect to each other. Each separator has a control element which signals the immediately preceding separator whenever the separator at which the control element is located does not have an article present. Thus, a separating operation is established with articles separated being directed toward the last separator by a sequence of signals arriving at the first and successive separators until discharge of the article at the last separator. Each separator is normally in an inoperative position and is operated only when the control element of the immediately following separator signals the absence therein of an article. Such as apparatus is based on the statistical principle that an error occurring at one separator is not likely to be repeated at another separator.

The above-discussed apparatus can be operated in a manner other than the described intermittent discharge of articles by separate signals. Such apparatus, however, is not quite as well suited for operations involving continuous separation of articles, particularly, when it is necessary to minimize error occurrences by using individual high performance separators.

Moreover, in the above-discussed apparatus, considerable wear on the switching elements is realized due to the intermittent operation of the separators during the process. Further, the separating efficiency of such apparatus is influenced by the spacing between individual articles being processed and can only be as close as the actual spacing between the separators. Flexibility in determining such spacing is therefore sometimes limited by the construction requirements of the apparatus.

SUMMARY OF THE INVENTION It is an object of the present invention to eliminate the drawbacks of the above-described apparatus and to provide a device for separating and individually discharging flat articles, such as letters, from a stack, while at the same time minimizing the number of errors that occur during such process. In brief, the present invention achieves the above-stated object by providing a first separating means and a second separating means with the inlet end of the second separating means being arranged at the outlet end of the first separating means. An articleconveying means is provided at each separating means and includes holding means in the form of suction holes. The suction holes provided at the second separating means are arranged to take hold of articles delivered to the second separating means by the first separating means only after the article has been delayed temporarily in the effective range of the second separating means. Interrupting means are also provided and are disposed at the first separating means to prevent removal of the top article from the stack of articles there provided when certain perdetermined conditions exist at the second separating means. Moreover, an interrogating means is provided which includes first and second sensing and signalling means in the effective range of the second separating means. The interrogating means is so arranged that the first and second signalling means cooperate with each other to the extent that when both emit a signal concurrently indicating a predetermined condition at the second separating means, a signal is sent fro-m the interrogating means to the interrupting means to prevent the top article in the stack from being conveyed and processed. The signal from the interrogating means to the interrupting means is transmitted only periodically and only within a predetermined time interval; namely, during the period of time after the trailing edge of an article has passed the sensing range of the first sensing means and before the leading edge of the next article has reached the sensing range of the first sensing means. While the holding means has herein been described as being in the form of suction holes, the holding means may also be in the form of appropriately disposed suction cups or suction heads, respectively.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 shows a plan view of one embodiment of the apparatus according to the invention.

FIGURE 2 shows a plan view of a second embodiment of the apparatus according to the invention.

FIGURE 3 shows a plan view of a third embodiment of the apparatus according to the invention.

FIGURE 4 is a sectional view taken along the line IVIV of FIGURE 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the embodiment shown in FIGURE 1 two suctiontype separating means or separators are connected in series. The separators contain suction troughs 1 and 2, respectively, each of which is connected to a suction source (not shown). Both separators have a common suction-type conveyor belt 3 which stretches over guide rollers 4 and 5 and is continuously circulated. The suction-type conveyor belt 3 is provided with holding means in the form of a holding device consisting of a plurality (4 are shown) of evenly distributed groups of suction holes 3', by means of which the top article of a stack 6 is taken hold of and moved. The leading edges of the articles thus removed from stack 6 are aligned along a wall 7. The suction conveyor belt 3 moves from the outlet end of the first separator to the inlet end of the second separator over a detour loop formed by

rollers

8, 9, 10, as shown. By this arrangement each of the groups of suction holes 3' enters the effective range of the second separator somewhat after the article they conveyed has done so.

At the outlet end of each of the separators, suction strippers 11 and 12, respectively, of a known construction are positioned opposite the suction conveyor belt 3. Conveying rollers 8, 13 and 4, 14, respectively, are also provided at each separator. By means of such rollers, in cooperation with the belt 3, the articles are further conveyed after they leave the effective range of suction troughs 1 and 2, respectively. It has been found advantageous to locate a means for delaying the articles in the conveying path of the second separator. This means is constructed as an abutting wall 15, as shown in FIGURE 1. Articles are conveyed against the abutting wall 15 with the assistance of a guide rail 16. A rotating brush 17 is also provided to guide the entering article.

As shown in FIGURE 1, the abutting wall 15 may be a transversely movable member with respect to the direction of movement of belt 3. The abutting wall 15 is reciprocated by means of an operating magnet (torquer magnet) 18 in synchronism with the arrival sequence of group of suction holes 3'. By such movement, it is intended that the abutting wall 15 temporarily close off the conveying path upon arrival of an article from the first separator and then open the conveying path once more depending on the thickness of the article and before the group of suction holes 3 arrive to take hold again of the article.

At the first separator, which removes the articles from stack 6, an interrupting means of known construction is provided which, depending on conditions of the second separating means, prevents removal of the top article from stack 6. The interrupting means or interrupter includes restraining finger elements 20 which are pivotally connected to axial member 19. The finger elements 20 are movable from an inoperative or rest position behind belt 3, above and below the same, by means of a coupling 21 and an actuating magnet 22, to an operative position Where the finger elements 20 restrain the top article of stack 6 and prevent it from reaching the surface of the conveyor belt 3 (as shown in FIGURE 1).

In addition to the foregoing, an interrogating means generally indicated as 24 is also provided. The interrogating means 24 consists of first and second sensing and signalling means, 23 and 26, respectively. The first sensing and signalling means 23 consists of a photoelectric device having a generator 23' and a receiver 23". The second sensing and signalling means 26 is also a photoelectric device and consists of a generator 26' and a receiver 26". The outputs of the first and second sensing and signalling means, 23 and 26, respectively, are connected to an AND-circuit in the interrogating means 24, thence to a switching stage 25. Switching stage 25, in turn, is connected to actuating magnet 22 of finger elements 20. By this arrangement, the restraining finger elements 20 are moved when a signal is received from the interrogating means that certain preconditions exist in the second separating means.

-In particular, the second sensing and signalling means 26 is so arranged with respect to the conveyor belt 3 that it senses the passing by of individual groups of suction holes 3. Upon sensing passage of the groups of suction holes 3', to which sensing and signalling means 26 are synchronized, a signal is sent thereby to one input of the AND-circuit of interrogating means 24. This signal is sent periodically and only during that interval of time which corresponds to when an article has passed beyond the sensing range of the first sensing and signalling means 23 and before the leading edge of a subsequent article has reached the same.

The present invention will more clearly be understood with a description of how the embodiment according to FIGURE 1 operates. Let it be assumed that no articles are present in the effective ranges of the two separating means and that the apparatus commences operation after insertion of a stack 6 into the first separating means. The restraining finger elements 20 are at this time in a rest position. As the first group of suction holes 3 on the conveyor belt 3 enter suction trough 1, they take hold of the lead or top article of the stack 6. The article is then moved along by belt 3, with aid of rollers 8 and 13 and rotating brush 17, into the effective range of the second separating means. At the second separating means, the abutting wall temporarily closes off the conveying path of belt 3 and the article is delayed for a short period of time by coming to rest thereagainst. The abutting wall 15 is a short time later caused to open such path, as explained above. Meanwhile the group of suction holes 3 have been detoured over

rollers

8, 9 and 10 to arrive at the second separating means after the article has reached the abutting wall 15. As the detoured group of suction holes 3' arrive, they move into suction trough 2 and take hold of the article once more to deliver the same to the discharge end of the second separating means defined by rollers 4 and 14. The article then exits from the second separating means in the direction of arrow 27.

During the operation described above, the first sensing and signalling means emits a signal which is sent to one input of the AND-circuit of the interrogating means 24. Such signal continues to be sent so long as an article is sensed by first sensing and signalling means 23. Such signal, however, can not reach the switching panel 25 until a second signal is concurrently received at the other input of the AND-circuit of interrogating device 24 from second sensing and signalling means 26. Until both signals are thus received at the AND-circuit, the restraining finger elements 20 will not be actuated by a signal from the switching panel 25. As discussed above, the signal from the second sensing and signalling means 26 is sent to the AND-circuit only during that period of time when the trailing edge of an article has passed beyond the sensing range of the first sensing and signalling means 23 and before the leading edge of a subsequent article has reached the same. Thus, in order for the signals from the two sensing and signalling devices to coincide, an article must be sensed at the first sensing and signalling means during the predetermined period of time the second sensing and signalling means is signalling the passing by of groups of holes 3. Until this happens, restraining finger elements will remain in a rest position and will not prevent the groups of suction holes 3' from taking hold of the next article in stack 6 and repeating the above-described operation.

Assuming that, in addition to the top article in stack 6, another article has been taken up and moved therewith. Such a situation arises when the articles adhere so tightly to each other that, in spite of the presence of suction strippers 11, they reach the effective range of the second separating means together. However, for reasons previously discussed, the probabilities are that the two articles will no longer be clinging to each other after the second separating operation at suction trough 2. Rather, the top article will be removed by the conveying group of suction holes 3' while the other article will remain in the effective range of the second separating means. Thus, after the top article has passed beyond the sensing range of the first sensing and signalling means 23, the other article will still be present and sensed by sensing and signalling means 23. Hence, the subsequent signal from the second sensing and signalling means 26 will arrive at the AND- circuit together with the continuing signal from the first sensing and signalling means 23 caused by the other article remaining in the range thereof. Thus, magnet 22 is actuated causing finger elements 20 to assume their operative position and thereby prevent the next article of stack 6 from being held and moved by a group of suction holes 3 which subsequently reach suction trough 1.

As soon, however, as the group of suction holes 3 prevented from taking hold of an article at the first sepa rator reach the range of suction trough 2, they take hold of the article remaining in the second separating means. As the next signal from second sensing and signalling means 26 is emitted, the first sensing and signalling means 23 will no longer be sensing and signalling the presence of an article in consequence of 'which the restraining fingers 20 will assume their rest position. The next article in stack 6 will then be removed and conveyed therefrom by an ensuing group of suction holes 3'.

According to the above description, a spacing results between consecutive articles which is somewhat greater than the spacing between the generator 23' and receiver 23" of the first sensing and signalling means 23 and the position of the leading edge of an article in stack 6. It is possible, however, to provide a closer spacing between consecutive articles within the framework of the present invention. If, for example, the distance between the first and the second separating means were increased, and the groups of suction holes 3 distributed over the suction conveyor belt 3 were doubled, it would be possible to operate the apparatus according to the invention With an additional article being interposed between an article leaving the second separator and an article being removed from stack 6. The only result of this would be that, in

the event of two articles being removed together from stack 6, the restraining finger elements 20 of the first separator would be in their operative position during more than one removal interval. Thus, a gap temporarily occurs in the article-conveying stream, since more than one removal interval is required to eliminate the temporary entry of two articles into the second separating means.

In order to make certain that an article carried through the first separator by a group of holes 3' arrives at the second separator before the group of holes 3', a pair of article-accelerating rollers may be provided at the outlet of the first separator in place of detouring

rollers

8, 9 and 10 for the conveyor belt 3. Such acceleration rollers could be inserted between the first and second separator at approximately the position of roller 13.

Instead of the guide rail 16, an upright conveyor belt may also be provided. It would also be advantageous under certain circumstances to provide a continuously driven belt below the floor in the conveying path of the second separating means.

Referring to FIGURE 2, an embodiment is shown which differs from that of FIGURE 1 in that the common suction conveyor belt 28 is not frictionally driven by rollers but rather by form-locking the belt 28 onto the guide roller 4. This arrangement can be accomplished, for instance, by an edge perforation similar to that provided on photographic film or, alternatively, the suction conveyor belt may be constructed as a sprocket band the sprockets of which engage corresponding recesses in a roller, as indicated in the vicinity of roller 4. Thus, the position of suction hole groups 28 of the conveyor belt 28 remains the same with respect to the drive means and this has certain advantages.

Moreover, an abutting wall 29 is provided instead of the stationary guide rail 16 and movable abutting wall 15. Abutting wall 29 is fixedly disposed and a guide means, having members 32, 33 which pivot around shafts 30, 31, respectively, is provided at the inlet of the second separating means. The guide members 32, 33 are rhythmically moved back and forth in keeping with the sequence of arrival at the second separating means of suction hole groups 28. By this arrangement, articles delivered to the second separating means first abut against wall 29 and subsequently are taken hold of by the suction conveyor belt 28. The guide members 32, 33 are parallel with respect to each other and can be constructed similarly to restraining finger elements 20. The guide member 32, like finger elements 20, is caused to return to a position behind the surface of suction conveyor 28 as the articles being conveyed are taken hold of thereby.

The pivotal movement of guide members 32, 33 is caused by a cam 34, driven by

sprocket wheels

35, 36 in synchronism with roller 4, hence with suction conveyor belt 28. The cam 34 periodically engages double-armed lever 38, which pivots around axis 37. Two levers 40 and 41 are provided which engage shafts 30 and 31, respectively. The levers 40, 41 are coupled to lever 38 by cou- .pling rod 39. Thus, when lever 38 pivots, it causes levers 40, 41 to turn shafts 30, 31, which in turn causes guide members 32, 33 to move. A tension spring 42 exerts a downward force on coupling rod 39. The elements 34 through 42 are illustrated as broken lines since they are disposed behind the plate 43 of the apparatus.

The form-locking drive of the suction conveyor belt 28, shown in FIGURE 2 also makes possible a simplification of the interrogating device 24. As in the FIGURE 1 embodiment, a first sensing and signalling means 23 in the form of a photoelectric device is provided as is an AND- circuit. However, in place of the photoelectric device of the second sensing and signalling means 26, a switch element 44 is provided. The switch 44 is in synchonism with the groups of holes 28', as they occur in the circulating suction conveyor belt 28, and is operated by a cam 25 which is driven by a gear 35.

Finally, in FIGURE 2 there is shown another form of the interrupting means. In place of finger elements 20 of FIGURE 1, a pneumatic valve element 46 is provided, which is actuated by a signal received from the first sensing and signalling means 23. In its inoperative position the element 46 connects suction trough 1 of the first separator with a suction source (not shown), while in its operative position the element 46 can create a normal pressure or overpressure, as required, in suction trough 1.

Referring to FIGURE 3, in the embodiment there shown, the two separators are provided with separate

suction conveyor belts

47 and 48, respectively. The

separate belts

47, 48 are moved by guide rollers 5, 49 and 4, 50,

respectively. The rollers 49 and 4, respectively, are the drive rollers of the two separating means and include form-locking means and are synchronized with respect to each other. The abutting wall 29, guide members 32, 33, as well as the interrogating means 24 including first and second sensing and signalling means 23, and 44, 45, respectively, are similar to that shown in FIGURE 2.

The interrupting means at the first separator of this embodiment can either be in the form of restraining finger elements 20, as in FIGURE 1, or in the form of a pneumatic valve element 46, as in FIGURE 2. However, FIGURE 3 shows yet another form of interrupting means.

This form of the interrupting means is best shown in FIGURE 4. The roller 4 includes a shaft 51 which is driven directly by a motor 55 by means of a chain 52 and wheels 53, 54. The roller 49 includes a shaft 56 which is driven by means of a chain 57 and wheels 58, 59. A power engaging means or clutch 60 is positioned between chain sprocket wheel 59 and shaft 56. Additional sprocket wheels 61 and 62, respectively, provide the drive for rollers 13 and 14, respectively. The clutch 60 is operatively connected to the switching stage 25 by means of a lead 25'. Clutch 60 is so constructed that upon receiving a signal from the photoelectric device of sensing and signalling means 23, which indicates the presence of an article in the second separator, it disengages the chain drive from driving conveyor belt 47 for one removal interval. The clutch 60 is then caused once again to engage the chain drive with conveyor belt 47 and it does this in phase-correct relationship to the position of the suction hole 48' on suction conveyor 48.

In a further embodiment of the present invention, it has been found advantageous to dispose a divider within the conveying path of the second separator. Such a divider exerts a force on incoming articles in a transverse direction to that in which such articles are being conveyed. As shown in FIGURE 3, such a divider is in the form of a disc 63 which corresponds in rotation to the direction in which the articles are conveyed and discharged. The disc 63, which is provided with projections 63', can not only effect the separation of articles which tend to cling to each other but can also direct articles coming into the second separator against the guide member 33, which is remote from the suction conveyor belt 43.

When two separate

suction conveyor belts

47, 48 are used, as shown in FIGURE 3, it is further possible to provide a material having a high frictional coefiicient in the form of a padding-type layer 47" or 48" of several millimeters thickness in the vicinity of each group of suction holes 47', 48, respectively. Such a layer would facilitate the taking of the top articles from the stack 6 of articles being separated.

It will be understood that the above description of the present invention is susceptible to various modifications, changes and adaptations and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims.

I claim:

1. Apparatus for separating and individually discharging relatively fiat articles from a stack, comprising, in combination:

first means for separating such a stack of articles and having an inlet end and an outlet end;

second means for separating having an inlet end and an outlet end;

means for conveying articles from said first separating means to said second separating means, said conveying means including holding means periodically operative at said first and second separating means for taking hold of the top article in such stack at said first separating means and periodically operative at said second separating means for taking hold of each article from said first separating means only after the article has been delayed momentarily while within the effective range of said second separating means;

interrupting means at said first separating means and responsive to a signal for preventing the top article in such stack from being conveyed;

interrogating means located at said second separating means and including;

(a) first means for sensing and signaling the presence of an article within the effective range of said second separating means;

(b) second means for sensing and signaling actuated, periodically, during a predetermined time period defined by the passing of the trailing edge of an article beyond and the arriving of the leading edge of the next article into the effective range of the first sensing and signaling means, to emit a signal which allows transmission of a signal from the first means for sensing and signalling to the interrupting mean during said predetermined time period which indicates the presence of an article in the effective range of said second separating means whereby said interrupting means is caused to respond by preventing the next article on top of such stack at the first separting means from being conveyed.

2. Apparatus as defined in claim 1, wherein said holding means include first and second holding devices provided at said first and second separating means, respectively.

3. Apparatus as defined in claim 2 wherein said holding devices are in the form of suction holes.

4. Apparatus as defined in claim 1, said conveying means including at least one endless conveyor belt and said holding means being in the form of groups of suction holes distributed over the entire length of said conveyor belt.

5. Apparatus as defined in claim 4 wherein said interrupting means includes a plurality of pivotal finger elements for restraining the top article in such stack, and means for moving said finger elements whereby, upon a signal being received from said interrogating means, said moving means is actuated and said finger elements are moved from a retracted position behind said conveyor belt to an operational position preventing the top article in such stack from being conveyed.

6. Apparatus as defined in claim 4 wherein said conveyor belt is common to both said first and second separating means, first and second suction troughs provided at said first and second separating means, respectively, cooperatively arranged with respect to said conveyor belt, a delay loop provided in said conveyor belt between the outlet end of said first separating means and the inlet end of the second separating means whereby each successive group of suction holes on said conveyor belt reaches the effective range of said second separating means only after the article each group has held to the outlet end of said first separating means reaches the effective range of said second separating means.

7. Apparatus as defined in claim 4 wherein said interrupting means includes a pneumatic valve member which in its inoperative position connects said first suction trough to said suction source and which, upon actuation by said interrogating means, is caused to assume an operative position whereby at least normal pressure is provided at said suction trough.

8. Apparatus as defined in claim 4 wherein said second sensing and signaling means includes a photoelectric sensor which is arranged with respect to said conveyor belt to sense said suction holes as they pass by on said conveyor belt.

9. Apparatus as defined in claim 4 wherein first and second suction troughs are positioned in the effective ranges of said first and second separating means, respectively, said conveying means being in the form of individually driven first and second conveyor belts provided at and cooperatively arranged with said first and second suction troughs, respectively, said suction holes being provided on both said first and second conveyor belts and said conveyor belts are driven according to a fixed phase relationship with respect to each other, hence with respect to the groups of suction holes provided on each.

10. Apparatus as defined in claim 9 wherein driving rollers are provided for said second conveyor belt and said second sensing and signaling means includes a switching deviceperiodically actuated by said driving rollers.

11. Apparatus as defined in claim 9, said interrupting means including a power transmitting means for driving said first conveyor belt, said power transmitting means being actuated by a signal from said interrogating means and responding to said signal by being disengaged from transmitting power to said first conveyor belt to thereby stop the same temporarily and then being engaged once more to cause said first conveyor belt to start again in a phase-correct relationship with respect to the suction holes provided on said individually driven second conveyor belt.

12. Apparatus as defined in claim 9 wherein said first and second conveyor belts, respectively, are provided a coating of material, having a high coefiicient of friction, in the vicinity of said suction means.

13. Apparatus as defined in claim 9 wherein a dividing means is located in the article conveying path of said second separating means which exerts a force transversely to the article conveying direction, on articles reaching said second separating means.

14. Apparatus as defined in claim 13 wherein said dividing means is in the form of a disc having projections provided circumferentially thereon and being rotated in a direction corresponding to the article conveying direction.

15. Apparatus as defined in claim 4 wherein a delaying means is positioned in the path of said conveyor belt at said second separating means whereby articles being conveyed in the path are delayed for a short period of time.

16. Apparatus as defined in claim 15 wherein said delaying means is an abutting member.

17. Apparatus as defined in claim 16 wherein said abutting member is transversely movable with respect to said conveyor belt and is synchronously reciprocated with re spect to the order in which said groups of suction holes on said conveyor belt are moved, whereby said abutting member temporarily closes the conveying path of said conveyor belt before an article arrives from said first separating means.

18. Apparatus as defined in claim 16 wherein said abutting member is stationary and a pivotal guide means is provided near the inlet end of said second separating means, said guide means being pivoted to and from said abutting member synchronously with respect to the order in which the groups of suction holes on said conveyor belt are driven, as a consequence of which articles reaching the effective range of said second separating means, after being conveyed thereto, are first guided against said abutting member and only thereafter are taken up by said conveyor belt once more.

19. Apparatus as defined in claim 18 wherein said guide means includes two movable elongated members extending substantially parallel with respect to each other and positioned so that the article conveying path of the conveyor belt extends between them, one of said elongated members being adjacent said conveyor belt and being made to abut said abutting member upon an article reaching the effective range of said second separating means and, thereafter, being made to retract behind said conveyor belt.

References Cited UNITED STATES PATENTS 3,194,552 7/1965 Buchwald 27l-56 3,258,262 6/1966 Rehm 271-56 RICHARD E. AEGERTER, Primary Examiner US. Cl. X.R. 27156, 26