US3523618A - Feeder devices - Google Patents

Description

1970 J. A. NIELSEN 3,523,618

FEEDER DEVICES Filed Aug. 25, 1968 2 Sheets-Sheet l INVENTOR.

J0me Baez/:7 Mass ATTORNEYS ug- 1970 J. A. NIELSEN 3,523,618

I FEEDER DEVICES Filed Aug. 23; 1968 1 2 Sheets-Sheet2 mvmron.

Jmroe 17061187 N/HSM ATTORNEYS.

United States Patent ()1 ice US. Cl. 214-11 5 Claims ABSTRACT OF THE DISCLOSURE A feeding device for sequentially delivering single articles to a conveyor, comprising at least two feeding stations each adapted to sequentially receive one article in a position in front of a release station in which releasable holding means are provided for preventing said articles from leaving the release station, actuation means operable to release said holding means, conveying means operable in response to release of said holding means for moving said article away from said release station towards the delivery end of said feeding stations but one as long as an article is passing the release station of this feeding station in response to said holding means in this station being released so as to prevent overlapping of articles sequentially being released from different release stations, coding means located adjacent each of said feeding stations and associated with code signal memoring means so as to be operable to set in said memory means a code signal for each article to be delivered from the feeding stations, and code signal transferring means operable to transfer said code signal from said memory means in any of said feeding stations to code signal receiving means in response to an article belonging to said code signal being released from the feeding station.

The present invention relates to a feeding device for conveyor systems and more particularly to a device for sequentially delivering single articles of goods to a conveyor from two or more feeding stations. Still more specifically though not exclusively the invention relates to a feeding device for automatic sorting apparatuses for post parcels and similar sorters.

During the last years different sorting equipments have been developed for making the sorting of post parcels, flight luggage etc. more or less automatic. It is a common feature in these systems that the articles are fed one by one into the apparatus and a code for the destination of each article is set by the operator as the article passes by a coding station. Hereafter the article passes out on a conveyor line past a number of discharging stations each corresponding to a certain destination, and according to the code set by the operator the particular article will be automatically diverted from the conveyor line as it reaches the discharging station for the particular destination. Some of these sorters are able to work with a remarkable speed, but since the actual speed of operation is limited by the manual code setting procedure it will be apparent that the actual sorting capacity cannot be increased to the technical possible magnitude unless the coding process can be accelerated. In some systems it will be possible to prepare or provide the articles with detectable code means subject to automatic reading or detection in a data reading destination selector unit at the entrance to the sorting conveyor line or in each discharging station so as to actuate the means for diverting the article from the conveyor to a destination in direct response to local detection of the code for this particular destination. In such cases it would be possible to let two or more operators provide the articles with the correct Patented Aug. 11, 1970 means at the desired discharging station as the articles pass by a coding station. Sorter systems have been developed in which according to this principle the articles pass an operator standing at a feeder station at the entrance to the conveyor line and setting a code at a key board according to the destination appearing in normal writing on each article passing his position. The code set is recorded in a so-called driving register and when the driving velocity of the articles on the conveyor line is known, it is possible to set the code electronically or otherwise follow the particular article until it reaches the discharge station corresponding to the code set. In this stage the recorded code data will actuate the diverter means for this particular discharging station. 'It will be appreciated that in a system of this nature where the coding of the articles is carried out sequentially as the articles enter the sorting machine, the sorting capacity is effectively limited by the speed with which the operator reads the destination on the single article and operates the key board in accordance therewith, and practice has shown that this reading and coding operation is in fact the bottle neck of the system. The articles may be delivered to the operator in a quick continuous flow and the automatic sorting on or from the conveyor line may take place rapidly, but the reading and code setting by necessity takes some time.

It is the object of the invention to provide a feeding device for a conveyor or sorter line which is able to deliver articles one by one to the conveyor line from at least two feeding stations in each of which an operator may make articles ready for delivery to the conveyor and get them delivered thereto without taking notice of to which times articles are delivered from the other feeding station or stations.

Another object of the invention is to provide a feeding device comprising two or more feeding stations and provided with means ensuring that the consecutive articles in the row of articles leaving the feeding device will show a suitable spacing from each other in order to enable a well defined and individual treatment of the articles in the conveyor line, such as removal or diversion from the conveyor.

Yet a further object of the invention is to provide a feeding device comprising at least two parallelly arranged feeding stations in each of which an operator can read the data such as an address on the articles and register the data for each article in a code setting register in such a manner that the article may later, on the said conveyor or otherwise, be treated in accordance with the code set, irrespectively of the sequence in which articles are delivered from the plurality of feeding stations.

Conveyor systems are known in which articles from two lines are moved into one row on a single line by means of a mechanical arrangement comprising a retractable stop member at the delivery end of each of the two feeder lines, these stop members being mounted on a see-saw-like supporting member ensuring that either one or the other stop member is in a protruding position in which it prevents article delivery from its associated feeder line while the other, respectively the first stop member is in a retracted position allowing at least the first article in its associated feeder line to be delivered to the common line. An alternate delivery from the two feeder lines is obtainable by means of an arrangement including in both feeder stations an arm which is pressed down by the article under delivery from the concerned feeder line, said arm when pressed down causing the advancing means for the next article on this line to stop and-when the article leaves the said arm-causing its associated stop member to move to its protruding stop position and thereby the other stop member to move to its released position, whereby an article will be released from the other feeding line with its leading edge in a certain distance from the rear edge of the article just delivered from the first feeder line, viz a distance corresponding to the distance between the stop member and the said arm. However, in the known systems of this kind, there is no question of moving articles onto a sorter line with individual code signals for the single articles being registered in each of the feeding stations and following the articles in correct sequence as the articles are delivered to the common line.

According to one aspect of the invention, the feeding device comprises at least two feeding stations each adapted to sequentially receive one article in a position in front of a release station in which releasable holding means are provided for preventing said articles from leaving the release station, actuation means operable to release said holding means, conveying means operable in response to release of said holding means for moving said article away from said release station towards the delivery end of said feeding device, means for blocking the holding means of the release station in all feeding stations but one as long as an article is passing the release station of this feeding station in response to said holding means in this station being released so as to prevent overlapping of articles sequentially being released from the different release stations, coding means located adjacent each of said feeding stations and associated with code signal memoring means so as to be operable to set in said memory means a code signal for each article to be delivered from the feeding stations, and means for transferring the code signal for a given article to code signal receiving means in response to said article being released from the feeding station.

If the articles to be handled are all of the same length the blocking means in a second release station may be actuated by the release of the holding means in a first release station and deactivated by means of a timing device ensuring that the next article from the second station does not leave the station until the article already delivered from the first station has moved so far towards the delivery end that there is space behind it for the article from the second station. This kind of automatic non-overlapping control is usable where the articles are of uniform length in each single of the feeding stations.

If the articles are of different lengths such as usual in case of post parcels, the deactuation of the blocking means may be controlled by a feeler operable to register the passage of the rear edge of an article under departure from a release station so as to ensure that the next article from any release station cannot be released until the rear edge of the first article has passed to a position in front of the leading edge of the next article to be released. Such feeler means may be provided as a photoelectric detecting device. When it is desired to work with a certain spacing between consecutive articles for example in automatic sorter systems, this is obtainable in a simple manner by the use of a time delay means in the operative connection between the feeler and the blocking means or alternatively as known per se by locating the feeler means in the desired distance in front of the release stations.

According to the invention the feeler means serving to actuate the blocking means may at the same time constitute means for detecting the length of the article under delivery in order to later cause the actuation of an appropriate number of diverting members or other handling means in accordance with the length of the article, whereby separate length measuring means are avoided.

In the following the invention is described in more detail with reference to the accompanying drawing, in which FIG. 1 is a perspective view of one embodiment of a feeding device according to the invention, and

FIG. 2 is a block diagram of the control circuit thereof.

The feeder device shown in FIG. 1 comprises a feeding table 2 with two feeding stations 4 and 6 separated by means of a longitudinal rib 8. These feeding stations are constituted by supporting rollers 10 mounted between the rib 8 and side frame portions 12 extending forwardly from the feeding table 2. The rollers 10 are rotated in anti-clockwise direction by means of friction belts 14 connected to a motor not shown. The two feeding stations continue into a common conveyor section 16 of forwardly tapered configuration and consisting of a number of rollers 18 rotated in anticlockwise direction by means of a friction belt 20 corresponding to the belts 14. The conveyor section 16 continues in a conveyor line 22 constituting an automatic sorting, conveyor; though this sorting conveyor does not in itself form part of the present invention, some of its functions will be described in more detail below.

Adjacent the front end of each of the feeding stations 4, 6 there is provided a retractable stop plate 24 which in an upwardly projecting position prevents parcels or other articles from being moved forwardly from the feeding station. Each stop plate 24 is mounted on the free end of a lever 26 which at its rear end is pivotally secured to bracket means 28 so as to be swingable between a raised position shown in the station 4 and a lowered position shown in the station 6. As a control means for this movement there is provided a pneumatic cylinder 30 underneath each of the levers 26.

Adjacent the front end of the rib 8 there is mounted a housing 32 for an electric lamp sending a transverse light beam out to both sides of the housing 32, and cooperating therewith there is provided a casing 34 for a photoelectric cell or photo resistor at each of the frame portions 12 so as to be able to register the passage of any article leaving each of the feeding stations.

It will be readily understood that an article placed on the rollers 10 will be moved into engagement with the stop plate 24 and moved further as soon as this stop plate is retracted to its lowered position. A parcel 36 is shown in a position in which it has just left the feeding station 4 and is now moving forwardly over the conveyor section 16. It is desired to ensure that all articles will have the same travelling time between the two ends of the conveyor section 16, but since some of the articles depending of their positions in the moment they are released from the stop plate 24 shall need a lateral displacement in order to be guided into the narrower conveyor 22, this would cause a difference in travelling time between articles travelling close to the center line of the conveyor section 16 and articles travelling close to the sides thereof in case these latter were guided inwardly by rigid side guiding rails; instead of such rigid guiding rails the conveyor section 16 is provided with side guiding means in the shape of a friction belt 38 driven with a velocity having a forwardly directed component equal to the advancing velocity of the articles on the rollers 18. Hereby the articles will be moved with uniform longitudinal velocity on the conveyor section 16 irrespectively of their departure position in the feeding stations.

Each feeding station is provided with a code setting box 40 having a key board 42 comprising a number of press buttons 44 enabling an operator to set a destination code for an article to be delivered from the feeding station and a release button 46 for actuating the cylinder 30 in order to release the article from the feeding station after the code has been set. The system is particu larly adapted for use in connection with automatic sorters for post parcels and the keys 44 are used to set a digital code corresponding to the address of the particular post parcel. The conveyor 22 constitutes the automative sorter line and along this line there is located a number of receiving stations, means being provided at each of these stations for diverting to the particular station all parcels travelling on the line 22 with this station as destination. The operation of these diverting means is controlled by a control system adapted so as to actuate the particular diverting means with such a time delay after the code has been set and the article has been released from the feeding station that the concerned article has in the meantime travelled the distance exactly to this particular position in which it will be engaged by said diverting means upon actuation thereof. Such systemshowever with one feeding station only-are generally known in the art and should therefore need no detailed description in the pres ent connection.

The rollers 18 in the conveyor section 16 are driven with a velocity which is somewhat higher than that of the rollers in the feeding stations. The control system is so adaptedas also described in connection with FIG. 2-that the stop plate 24 in each feeding station upon retraction thereof is held in the retracted position until the rear edge of the article passes the photoelectric measuring equipment 32, 34, whereas the cylinder 30- is actuated to raise the stop plate to its projecting holding position as soon as the article is no longer breaking the light beam on the photo cell 34. In order to ensure a correct operation of the said diverting means it is important to provide a suitable spacing between consecutive parcels, and some spacing is necessary already by the passage of the photoelectric means because it must be ensured that the light beam is reestablished after the passage of each single parcel so as to enable the stop plate 24 to be operated for holding the next parcel back at least until the correct spacing from the foregoing parcel has been obtained. The driven rollers 10 act to move all parcels in the feeding station forwardly so that when more parcels are lined up therein there will usually be no spacing between them. However, when the stop plate 24 is releasing the first parcel this will move out on the rollem 18 followed in the feeding station by the other parcels 1n the row, and since the rollers 18 will move the first parcel away with increased speed a spacing to the next parcel will automatically be obtained in this manner so that the photoelectric means will always register the passage of each single parcel.

In operation, the operator at each feeding station pushes a parcel out on the rollers 10, reads the address on the parcel, and operates the code setting buttons 44 correspondingly. The parcel is moved by the rollers 10 until it is stopped by the protruding stop plate 24. The operator, thereafter, presses the release button 46, and if no other parcel is under release from the other feeding station the stop plate 24 will hereby be moved to its retracted position to thereby release the parcel for further travelling; simultaneously, the code set on the box 40 will be fed into an electronic register serving to actuate the diverting means adjacent the destination of the parcel on the line 22 exactly when the parcel has reached this diverting station.

As soon as the rear edge of the parcel passes the light beam from the lamp 32 the photo cell 34 will cause the stop plate 24 to be raised into itsstop position, and this is done almost instantaneously so that the leading edge of the next parcel, if any, will be stopped by the plate 24 after the spacing provided for as described above. For ensuring a well defined start of the parcel in response to the stop plate 24 being retracted as well as a safe acceleration of the parcel on the first rollers 18 in the conveyor section 16 there is provided a frictional layer on the rollers in the neighbourhood of the stop plate 24 so that these rollers will get a good grip on the parcels, however without preventing the roller 10 immediately before the plate 24 to rotate under a parcel held back by the plate 24.

The control means of each control box are connected to a common control unit in which means are provided for ensuring that the stop plate 24 in one of the feeding stations cannot be released as long as the stop plate in the other feeding station is released. When one stop plate 24 is released in response to the release button 46 being operated, this will automatically cause the operative connection between the release button 46 and the stop plate 24 in the other feeding station to be broken, and the control unit is so adapted that this operative connection is not reestablished until the light beam to the photo cell 34 in the first station has been reestablished upon passage of the rear edge of the article leaving this station, and in order to ensure the correct spacing the said operative connection will first be reestablished with a certain time delay after the light beam has been reestablished. The control unit may be so adapted that both feeding stations are made parallelly operable after the said tlme delay so that the next parcel will leave that of the stations 1n WhlCll the release button 46 is first operated. Preferably, the control unit contains memory means for registering the operation of the release button 46 in such a manner that the button may well be operated whilst a parcel is leaving one of the stations, but the release signal to the corresponding stop plate 24 will be given by the memory unit first when the condition for the release, i.e. a correct spacing from the foregoing parcel as determined by the photoelectric means in connection with the time delay unit has been reestablished.

In a preferred embodiment, the memory unit is designed so as to be able to memorize two or four code settings and release signals from each of the control boxes 40. The parcels will then be delivered or released in the same sequence in which the code settings from the two control boxes were transferred to the memory unit by operation of the buttons 46. The control boxes 40 further have buttons for'cancelling of a code already set, and for repeating a code already set.

It will be appreciated that the two operators may act entirely independent of each other and it will also be appreciated that the system described is in no way limited to the use of only two feeding stations.

The feeder device according to the invention may well be used in connection with already existing sorter lines 22. Some of the known sorters are provided with automatic spacing control means adjacent the inlet end of the conveyor line and a memory register for the code settings fed to the sorter so as to provide for exact synchronisrn between parcel positions and the timed progress of the codings. This memory register may easily be fed from the said memory unit of the feeding device, and it may even be practical to work with an intermediate memory register covering the passage of the parcels on the conveyor section 16. The memory unit that may be able to store for example four code settings hereby transfers the code setting for any parcel under departure from the feeding station to the said intermediate memory register which may contain for example five or six sequential code settings according to the maximal number of parcels being able to travel simultaneously on the conveyor section 16. As the parcels hereafter pass the automatic spacing control means on the sorting conveyor 22 the code settings are transferred further to the memory register on the sorter itself.

As mentioned, the coding and code transferring means belong to the known art, and it is believed that the detailed construction of the circuits in the said control unit of the feeding station should need no special description since it will be no problem for persons skilled in the art to build up a unit showing the function-a1 characteristics described above.

In order to further exemplify the invention a block diagram of a control circuit for the feeder device is shown in FIG. 3. This control system is so adapted that one of the feeding stations takes precedence over the other station, i.e. parcels from the other station will not be released until a moment in which there is no parcel ready for delivery from the first station. Theoretically, this could mean that the operator at the second station should wait for a pause in the operation of the first station, but in practice one operator will not be able to continuously follow up the maximal delivery capacity of his feeding station so that intervals will often occur in which parcels from the other station may be released. For this reason the system will work almost as if the two stations had been controlled in parallel, without one taking precedence over the other.

Generally, in the system shown, the digital code set in the control box 42 is transferred to a driving register 50 as soon as a parcel is released from one of the feeding stations. According to known principles the binary destination code corresponding to the particular parcel is repeatedly supplied to the driving register during the time in which the parcel is under passage of the photoelectric measuring equipment whereby the length of the parcel is automatically detected. The code setting is transferred repeatedly by means of transferring pulses occurring at a frequency proportional to the advancing speed of the conveyor as for example obtained by switch means actuated by constantly spaced actuators mounted in connection with the driving means for the conveyor. In accordance with the frequency of these pulses the code setting is thereafter advanced stepwise in the driving register 50 so as to electronically follow the parcel in its movement along the conveyor. When the particular code setting or signal hereby reaches the driving register stage corresponding to the actual destination of the parcel the code signal will here cause an actuation of suitable diverter means such as a tilting mechanism for the supporting rollers of the conveyor or for corresponding slats in a moved conveyor band to which the parcels are delivered from the tapered conveyor section 16 of the feeder device shown in FIG. 1. Thus, when the parcel reaches its point of destination, as many rollers of slats as corresponding to the length of the parcel will be tilted so as to let the parcel slide out into the receiving station at this place without influencing the parcels immediately preceding and following the diverted parcel.

In FIG. 2 the diverter means are designated 52 and are shown located at dilferent points along the driving register proportional to the location of the diverting stations along the conveyor. It will be appreciated that any suitable type of diverter mechanisms other than the said tilting arrangement may also be used, for example socalled live arm or dead arm diverters.

When a destination code has been set in the control box 40 the particular code is deposited in binary form in a memory unit 54. When the release button 46 is thereafter operated the code signal is transferred to another memory unit 56 designated a queue register and containing four memory circuits arranged in series. The signals pass a selector 58 of the kind serving to transfer the signal to the first memory circuit in the queue register which is not already containing a previously transferred code signal. The first code signal in the queue register is adapted to be transmitted to the driving register 50 through a gate 60 in response to a trigger impulse being supplied through a conductor 62.

The control voltage for the system shown in applied through a wire 64 which is connected to a switch 66 controlled by the stop member 24 which in its raised position holds the switch in position I and in its lowered position holds the switch in position II. When in position II the switch 66 supplies control voltage to another switch 68 which in its tum is controlled by the photo cell 34 so as to assume position I when the photo cell registers a light beam from the lamp 32 and in position II when there is no beam hitting the photo cells. The voltage for the trigger impulses from the said conductor 62 is supplied from the photo cell switch 68 in the position II thereof, and it will be noted that no such voltage is applied as long as the stop member 24 assumes its raised position, i.e. the switch 66 is in position I, and furthermore as long as the photo cell registers a light beam from the lamp 32, the switch 68 hereby being in position I. On the other hand, when the stop member 24 moves down and releases a parcel, and when thereafter the parcel breaks the light beam to the photo cell 34, the trigger wire 62 will be connected to the voltage supply wire 64 through the switches 68 and 66 and through a pulse switch 70 designated ADVANCING PULSES; this switch is operated intermittently with a frequency corresponding to the advancing velocity of the parcels on the sorter conveyor so as to cause a correctly timed delivery of code signals to the driving register 50. The gate 60 is connected to position I of the switch 68 so as to be closed whenever the photo cell 34 registers a light beam from the lamp 32; this arrangement serves to additionally ensure that no code signals are transferred to the driving register as long as no parcel is passing the photo cell, but the arrangement is not strictly necessary because the said trigger pulses may occur only when the switch 68 is in position II, i.e. when the light beam is broken.

Through a wire 72 the queue register 56 is connected to a gate 74 in the connection between position I of the switch 66 and a relay 76 for activating the cylinder 30 to lower the stop plate 24. The wire 72 transfer an opening signal to the gate 74 whenever there is a code signal set in at least one of the memory circuits of the queue register 56. Thus, the gate 74 is opened as soon as the release button 46 is operated, whereafter the control voltage may proceed towards the relay 76 in order to release the stop member 24. However, the gate 74 is connected in series with another gate 78 connected to the control system of the other feeding station so as to be closed whenever the stop member 24 belonging to this feeding station is held in its lowered position, i.e. when a parcel is under departure from the second feeding station. Furthermore, in the control line to the relay 76 there is inserted a delay circuit 80 serving to prevent operation of the stop plate releasing means until a desired spacing from the foregoing parcel has been obtained. When the release button 46 is operated and no parcel is under departure from the second feeding station the control voltage from the line 64 will pass the switch 66, the gate 74, and the delay circuit 80 to thereafter cause the relay 76 to retract the stop member 24 and thereby release the parcel, the destination code of which has been set in the first memory circuit of the queue register 56.

In the manner described above the parcel starts to travel out on the conveyor section 16, and a very short time after the release the front edge of the parcel will break the light beam on the photo cell 34. By the lowering of the stop member 24 the switch 66 will be switched over to position II so as to pass the control voltage to the photo cell switch 68. After the said very short time this switch will be shifted to its position II which causes the gate 60 to open and control voltage to be supplied to the triggering system 70, 62. The trigger pulses will cause the first code signal in the queue register 56 to be repeatedly delivered to the driving register 50 as long as the switch 68 is in position II, i.e. as long as the parcel is actually passing the photo cell 34. As soon as the light beam on the photo cell 34 is reestablished upon passage of the rear edge of the parcel the switch 68 is shifted to position I whereby the gate 60 closes and the trigger pulses are stopped. Through a wire 82 position I of the switch 68 is connected to a relay 84 for activating the cylinder 30 so as to raise the stop member as soon as the light beam is reestablished in order to stop the next parcel from directly following the parcel under departure. In the wire 82 there is inserted a gate 86 having a connection 88 to position II of the switch 68 so as to be open when voltage is supplied to position II. In the connection 88 there is a holding circuit 90 including a capacity serving to hold the opening signal on the gate 86 a short time after the control voltage has been removed from position II of the switch 68. The gate 86, therefore, will be open in the moment the switch 68 shifts to position I so as to enable a control signal to pass to the relay 84 to raise the stop member 24; simultaneously a control signal is applied to a shift unit 92 serving to cancel the code signal in the first memory circuit of the queue register 56 and to deplace the following code signals in the register one step towards the left so as to bring the next code signal ready for delivery to the driving register 50 in response to further trigger pulses being applied through the wire 62 at a later moment.

When the relay 84 has been actuated to raise the stop plate 24 the switch 66 will hereby be brought back to its position I, and if there is already a new code signal present in the queue register 56 the gate 74 will be open. If there is still no parcel under departure from the second feeding station also the gate 78 will be open, so that after a certain time as controlled by the delay circuit 80 the relay 76 will again be actuated to cause retraction of the stop plate 24 whereafter the described operation cycle is repeated and the next parcel released from the feeding station with prescribed spacing from the first parcel. It should be mentioned that when the switch 66 is brought into position II in response to the stop plate 24 being lowered the control voltage will pass to position I of the switch 68, i.e. in direction towards the relay 84 and the shift unit 92; however, since a short but nevertheless relatively long time has gone since the control voltage was removed from position 11 of the switch 68 the voltage holding unit 90 has in the meantime caused the gate 86 to close so that the control voltage will not reach the relay 84 or the shift unit 92 in response to the switch 66 being brought to position II, and a short time thereafter the released parcel will break the light beam so as to cause the switch 68 to shift to position II and thereby start the delivery of code signals to the driving register 50.

With a few exceptions the control circuit for the other feeding station, shown in the lower half of FIG. 2, is built up in exactly the same manner as the described control system of the first feeding station. The switch 66 registering the position of the stop plate 24 of the second feeding station has its position II connected to the gate 78 of the control system described above so as to cause a closing of this gate whenever the stop member 24 assumes its retracted position, i.e., when a parcel is under delivery from the second feeding station. As mentioned this will prevent the release mechanism of the first feeding sta tion to go in operation until the stop member 24 is again brought to its raised stop position. If the release button 46 of the first station has been operated during the delivery of a parcel from the second station the next delivery from the first station will hereby automatically be deferred until the stop member 24' is raised; since in this situation the gate 74 is already opened the opening of the gate 78 in response to the stop member 24' being raised will automatically cause the relay 76 to be operated after the prescribed delay, so that also in this case a quick release though with correct spacing from the foregoing parcel will be obtained independently of the manual activation of the system.

The gate 78 in the second feeder station is connected to the wire 72 from the queue register 56 in the first station in such a manner that the gate 78' is closed whenever there is a signal on the wire 72, i.e. whenever there is one or more code signals remaining in the queue register 56 of the first station. The operator of the second station may preset the code of up to four parcels in the queue register 56', and the first of these code signals together with the corresponding first parcel in the second station will be transferred to the driving register 50, respectively the sorting conveyor as soon as there are no parcels waiting or under departure in the first station. As mentioned this makes the first station take precedence over the second station such as often fully usable in practice.

Obviously, the coupling of the two systems may be made otherwise, for example with the use of a selector enabling the two stations to work alternately. A control system of this kind may in itself be made in several possible manners of which an example is indicated in FIG. 2 in dotted lines. In this system the gate 78' is connected directly to position II of the switch 66 as shown by the wire 100, and not to the connection 72 between the queue register 56 and the gate 74, so that in this case the two control systems are identical and also identically interconnected, The gates 78 and 78' are through wires 102, respectively 104 connected to opposite terminals of a selector 106 adapted to be switched downwardly by activation of an operation member 108 and upwardly by activation of an operation member 110. These members 108, 110 are operatively connected to the wires 82, respectively 82' so that when a control signal is applied to the relay 84 the member 108 is actuated to switch the selector 106 down in order to connect the wire 102 with the control voltage on the input line 112 of the selector 106. Hereby a closing voltage is applied to the gate 78 so that this gate cannot be opened until the selector 106 is switched back to its initial position. This switching back is effected by the member 110 in response to a control signal occuring in the wire 82', i.e. in response to the second feeding station having completed the delivery of one parcel therefrom. When the selector 106 is thereby switched back to the position shown the gate 78 will be closed and the gate 78 opened whereafter a parcel may be delivered from the first station. It will be appreciated that in this manner parcels will be alternately delivered from the two feeding stations.

As indicated in FIG. 2 the driving register 50 has a first portion 51 which is not connected to any diverter unit 52. This section 51 geometrically corresponds to the tapering conveyor section 16 shown in FIG. 1. It is an important feature that the code signals from the queue registers 56 and 56' are transferred directly to the driving register because this involves that the photo cell 34, 34' are used both for controlling the correct spacing between consecutive parcels and for detecting the length of each parcel leaving the feeding stations. Hereby a high degree of simplicity is obtained in the device according to the invention, since difierent functions are carried out by the same means.

Another aspect of the invention is the provision of the described means for providing a safe and well defined spacing between consecutive articles leaving each of the feeding stations, and these means are perfectly usable in connection with sorters having one feeding station only.

FIG. 3 shows a simplified control system in which the two feeding stations are working in parallel using a single queue register being adapted to receive code signals from both control boxes in the sequence in which the release buttons 46 and 46 are operated. The destination code signals from the box 40 include an additional identification signal specific for this box, and the signals from the other box 46' correspondingly include another identification signal. The code signal to be transferred from the queue register to the driving register in connection with the release of the parcel belonging to this signal, whether present in one or the other of said feeding stations, is first passed to a detector or selector unit reading the identification signal and causing the stop member 24 or 24' in the correct feeding station to be retracted whereafter the parcel is delivered from the station together with the destination code signal thereof.

In this embodiment there is used a single queue register designated 120. As in FIG. 2 the control boxes 40 and 40' are provided with memory units 54 in which the code set by means of the keys 42 is temporarily stored in binary form until it is transferred to the queue register by means of the release button 46. The selector 58 shown in FIG. 2 is here included in the queue register and connected in parallel to the two memory units 54 and 54' in such a manner that any code signal delivered from any of these control boxes will be set in the first memory unit of the queue register which is not already containing a previously transferred code signal. The memory units 54 and 54' are so adapted that a code signal released therefrom will automatically be completed with an identification code signal referring to either the unit 54 or the unit 54' as the case may be, and the memory units in the queue register are adapted to also memorize this identification signal. An interconnection 122 is established between the two boxes 40 and 40 so as to block the release button of one box during the actuation of the release button of the other box whereby it is prevented that signals from the two boxes may be simultaneously applied to the same memory unit in the queue register 120. Provisions are also made, in a manner not indicated, to block the release buttons of both boxes when code signals have been set in all the memory units of the queue register.

As soon as the first code signal is transferred to the first memory unit 124 in the queue register this signal is transmitted to a selector 126 passing the destination code signal further towards the driving register 50 and besides capable of reading the identification signal mentioned above; an indentification signal from the unit 40, 54, i.e. box I, will cause the selector to actuate a relay 76 serving in its turn to actuate the cylinder 30 to retract the stop member 24 in that of the feeding stations which belong to the said box I. On the other hand, if the signal from the first unit 124 in the queue register originates from the other box unit 40, 54' (box II) the selector 126 will read the corresponding identification signal and cause a relay 76' to retract the stop member 24' in the other feeding station. A gate 128 is arranged in the connection between the selector 126 and the driving register 50, and this gate is adapted to be closed as long as both of the photo cells 34, 34' registers the light beam from the lamp 32, i.e. as long as no parcel is under delivery from any of the feeding station; it will be appreciated that under these circumstances no code signals are transferred to the driving register.

As soon as one of the stop members have been re tracted in response to the selector 126 reading the identification signal contained in the code signal to be delivered together with the parcel under delivery, this parcel will start moving out onto the conveyor section 16 and thereby break the light beam to the photo cell in its feeding station. The photo cell controls a switch 130 applying control voltage on an output line 132 as long as the photo cell does not receive light from the lamp 32. This voltage is through a wire 134 applied to the unit 70 which as described in connection with FIG. 2 serves to generate output pulses corresponding to the velocity of the conveyor means in the conveyor section 16 as well as the sorter line 22. These pulses are through wire 62 applied to the gate 128 so as to repeatedly open and close this gate as long as the released parcel is under passage of the photo cell. By this operation of the gate 128 the code set in the first memory unit 124 of the queue register 120 will intermittently pass to the driving register 50 so as to fill up as many units therein as corresponding to the length of the parcel being released. When the rear edge of the parcel has passed the photo cell the light beam will be reestablished so as to cause the switch 130, respectively the switch 130 to shift to position light after dark and thereby remove the control voltage from the wire 132 so as to close the gate 128. Through a wire 136 the pulse generating unit 70 still transfers advancing pulses to the driving register '50 in order to provide trigger impulses thereto so as to cause the code settings therein to move forwardly through the register in a stepwise movement proportional to the advancing velocity of the parcels.

As soon as the switch 130 respectively 130 is shifted to the position light after dark a relay 84, respectively 84 will be actuated and cause the retracted stop plate 24 or 24 to be raised to its stop position; this takes place almost immediately after the released parcel has passed the photo cell so that the next parcel in the row in the concerned feeding station will hit the stop plate and be held back thereby. In this position of the switch 130 respectively 130' control voltage will also be applied to an output wire 138 which is connected to the selector 126 through a unit 140 which serves to send a cancelling impulse to the selector 126 so as to cancel the reading of the identification code signal and to prepare the selector to react on the occurrence of a new identification code signal. Simultaneously, from the wire 138, control voltage is applied to a shift unit 142 through a delay circuit 80, and the shift unit 142 is connected to the queue register so as to cause the code setting in the first memory unit 124 to be cancelled and the following queue of code sigals to be advanced one step towards the left so as to bring a new code signal into the memory unit 124. At this time the switch 130, respectively has shifted to position steady light so that the signal on the selector 126 from the cancelling unit has ceased. Therefore, the selector 126 now reads the identification code signal of the new code signal in the unit 124, whereafter the described operation cycle is repeated. The delay unit 80, as in the embodiment previously described, serves to delay, the shift in the queue register until the previously released parcel has moved sutficiently to ensure the desired spacing from the next coming parcel.

Due to the identification code signals used the device will work correctly independent of in which sequence the release buttons in the two control boxes are actuated, and of course the queue register may contain as many memory units as desired, for example corresponding to the maximal number of parcels which can be lined up in the two feeding stations.

It will be appreciated that the system involves no limitation as to the number of different feeding stations, since the device will work in the manner described when the code signals from each of the feeding stations are completed with a specific identification code signal for the particular feeding station, since the selector 126 will then cause the stop member in the correct feeding station to be retracted in connection with the destination code signal for the parcel to be released being transferred to the driving register 50.

It is not even necessary that each of the stations are provided with separate photo cells; thus, in FIG. 1 the lamp 32 may be removed and mounted instead of the photo cell 34' so that the photo cell 34 will register the parcel delivery from both of the stations shown. The photo cell switches 130 and 130' are connected in parallel and might therefore be substituted by one switch only. The relays 84 and 84 would in this case be substituted by one relay connected further in the circuits in such a manner that upon actuation it would cause a stop member lowered in any of the feeding stations to be raised. Since there can only be one stop member lowered at a time there are no difiiculties in providing a system in which the lowering of the stop members are selectively controlled by the selector 1 26 whilst the returning of the stop members to the holding position is controlled by a unit common to all stop members, for example with the use of a purely mechanical resetting system including a raisable cross beam extending crosswise underneath all the carrier arms 26 of the stop members 24 so as to raise any lowered stop member when it is raised itself in response to the relay 84 being actuated. Alternatively the relay '84 may send an actuation signal to separate raising relays in all feeding stations at one time whereby an actual raising of the stop members will only take place in the station in which the stop member has been lowered.

What is claimed is:

1. A feeding device for sequentially delivering single articles to a conveyor, comprising at least two feeding stations each adapted to sequentially receive one article in a position in front of a release station in which releasable holding means are provided for preventing said articles from leaving the release station, actuation means operable to release said holding means, conveying means operable in response to release of said holding means for moving said article away from said release station towards the delivery end of said feeding device, means for blocking the holding means of the release station in all feeding stations but one as long as an article is passing the release station of this feeding station in response to said holding means in this station being released so as to prevent overlapping of articles sequentially being released from different release stations, coding means located adjacent each of said feeding stations and associated with code signal memoring means so as to be operable to set in said memory means a code signal for each article to be delivered from the feeding stations, and code signal transferring means operable to transfer said code signal from said memory means in any of said feeding stations to code signal receiving means in response to an article belonging to said code signal being released from the feeding station.

2. A feeding device as claimed in claim 1, in which each of said feeding stations is operable to receive at least two aligned articles, said conveying means comprising at first continually and endlessly moving supporting surface located in each feeding station and being operable to frictionally engage the articles resting thereon so as to tend to move the articles forwardly and against said holding means and a second continually and endlessly moving supporting surface located in a common conveyor section in front of the holding means of all feeding stations and also operable to frictionally engage an article released from any of said feeding stations in order to move the released article towards the delivery end of said feeding device, said second conveying means being driven at a speed higher than that of said first conveying means, feeler means operable to register the passage of the rear edge of a released article being located adjacent said releasable holding means and being operatively connected with means for actuating said holding means so as to bring said holding means to their stop position in response to the rear edge of the released article passing said feeler means.

3. A feeding device as claimed in claim 1, in which articles from all feeding stations are delivered to a common conveying section the side walls of which are tapering towards a delivery end therefor, said tapering sides being defined by continually and towards said delivery end endlessly moving wall portions capable of frictionally engaging a side portion of an article being moved thereagainst, whereas said moving wall portions are driven at a speed having a velocity component in the moving direction of the conveying means in said common which is substantially equal to the speed of said conveying means.

4. A feeding device as claimed in claim 1, in which feeler means for detecting the passage of the rear edge of a delivered article past said holding means of any feeder station are provided so as to cause actuation of returning means for bringing the holding means to their stop position in response to said passage, said feeler means also serving to register the passage of the front end of the released article, and in which means are provided for detecting the length of said article, said length detecting means being actuated by said feeler means in response to passage of the front end of the article and disactuated by said feeler means in response to passage of the rear edge of the article.

5. A feeding device as claimed in claim 1 in which said coding means are adapted to provide each code signal transferred to said memory means with an identification code signal specific for each of the different feeding stations, whereas selector means are provided for reading the identification code signal of any article under release from the feeding device so as to cause retraction of the holding means in the feeding station from which the identification signal originates.

References Cited UNITED STATES PATENTS 3,327,836 6/1967 Burt 214-11 XR GERALD M. FORLENZA, Primary Examiner R. B. JOHNSON, Assistant Examiner US. Cl. X.R. 198-32

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