Tray sealing machine and method for gently picking up a tray

Abstract

The present disclosure relates to a tray sealing machine and, in addition, to a method for gently picking-up trays and for gently depositing sealed packages.

Claims

1. A tray sealing machine comprising at least one feed unit for conveying trays in a production direction, a sealing station arranged downstream of the feed unit, when seen in the production direction, and used for producing packages, at least one discharge unit arranged downstream of the sealing station, when seen in the production direction, as well as a gripper unit configured to, in a conveying cycle, pick up trays provided on the feed unit and convey them into the sealing station for a tray sealing process taking place in the sealing station as well as pick up packages produced within the sealing station and convey them to the discharge unit, wherein the sealing station comprises a tool upper part, which includes a sealing tool, as well as a tool lower part, which includes a support plate unit for depositing thereon the trays conveyed into the sealing station and a vertically adjustable tray holder for picking up and conveying the trays transferred to the support plate unit towards the tool upper part, the tray sealing machine additionally comprising a lifting mechanism configured to move the tray holder from a first position, at which the tray holder occupies a starting position in an open state of the sealing station, to a second position, at which the tray holder occupies a working position located closer to the tool upper part in a closed state of the sealing station, during a first predetermined motion sequence, the tray holder being adapted to be moved during the first motion sequence by means of the lifting, mechanism in such a way that the tray holder will pick up the trays, which are provided on the support plate unit, at a predetermined pick-up speed, wherein the tray holder is adapted to be moved, by means of the lifting mechanism, from the second position back to the first position during a second predetermined motion sequence, which is provided for opening the sealing station, in such a way that the tray holder will transfer the produced packages accommodated therein to the support plate unit at a predetermined depositing speed, with a rate of speed change over time of the tray holder having changed from a negative value to a positive value during the second motion sequence before the tray holder has reached the predetermined depositing speed.

2. The tray sealing machine according to claim 1, wherein from a transfer moment, at which the packages have been transferred to the support plate unit, the tray holder is movable at the depositing speed for a predetermined time interval.

3. The tray sealing machine according to claim 1, wherein the tray sealing machine is configured such that the rate of speed change over time of the tray holder will have changed from a negative value to a positive value during the second motion sequence after the packages have been transferred to the support plate unit at the depositing speed and before the tray holder has returned to the first position.

4. The tray sealing machine according to claim 1, wherein the pick-up speed and/or the depositing speed are variably adjustable at the tray sealing machine.

5. The tray sealing machine according to claim 1, wherein the tray sealing machine is configured such that the tray holder will reach the pick-up speed at a predetermined pick-up position during the first motion sequence, before the trays provided on the support plate unit have been received, on tray edges formed thereon, by the tray holder.

6. The tray sealing machine according to claim 1, wherein the tray sealing machine is configured such that the tray holder will reach the depositing speed at a predetermined depositing position during the second motion sequence before the packages have been deposited on the support plate unit by means of package bases formed thereon.

7. The tray sealing machine according to claim 1, wherein the tray holder, together with the trays accommodated therein, is movable at the pick-up speed for a predetermined time interval.

8. The tray sealing machine according to claim 1, wherein the tray sealing machine is configured such that a rate of speed change over time of the tray holder will have changed from a positive value to a negative value during the first motion sequence before the tray holder has reached the predetermined pick-up speed.

9. The tray sealing machine according to claim 8, wherein the tray sealing machine is configured such that the rate of speed change over time of the tray holder, including the trays accommodated therein, will have changed from a positive value to a negative value during the first motion sequence before the tray holder arrived at the second position.

10. A method of lifting and lowering a tray holder at a sealing station of a tray sealing machine, wherein, when the tray holder is being lifted, trays, which are provided on a support plate unit, are picked-up by means of the tray holder and conveyed to a tool upper part positioned above the tray holder, so as to carry out a tray sealing process, wherein the tray holder is moved by means of a lifting mechanism from a first position, at which the tray holder occupies a starting position in an open state of the sealing station, to a second position, at which the tray holder occupies a working position located closer to the tool upper part in a closed state of the sealing station, during a first predetermined motion sequence, wherein the tray holder picks up the trays, which are provided on the support plate unit, at a predetermined pick-up speed, wherein subsequent to a tray sealing process, the tray holder is moved by means of the lifting mechanism from the second position back to the first position during a second predetermined motion sequence in such a way that the tray holder will transfer, at a predetermined depositing speed, produced packages accommodated therein to the support plate unit, with a rate of speed change over time changing from a negative value to a positive value during the second motion sequence before the tray holder reaches the predetermined depositing speed.

11. The method according to claim 10, wherein from a transfer moment, at which the packages have been transferred to the support plate unit, the tray holder is lowered still further at the depositing speed for a predetermined time interval.

12. The method according to claim 10, wherein the rate of speed change over time of the tray holder changes during the second motion sequence from a negative value to a positive value after the packages have been transferred to the support plate unit at the depositing speed and before the tray holder has returned to the first position.

13. The method according to claim 10, wherein from a moment, at which the trays have been received by the tray holder, the tray holder is lifted at the pick-up speed for a predetermined time interval.

14. The method according to claim 10, wherein a rate of speed change over time of the tray holder changes from a positive value to a negative value during the first motion sequence before the tray holder reaches the predetermined pick-up speed.

15. The method according to claim 14, wherein the rate of speed change over time of the tray holder, including the trays accommodated therein, will change from a positive value to a negative value during the first motion sequence before the tray holder arrives at the second position.

16. A tray sealing machine comprising at least one feed unit for conveying trays in a production direction, a sealing station arranged downstream of the feed unit, when seen in the production direction, and used for producing packages, at least one discharge unit arranged downstream of the sealing station, when seen in the production direction, as well as a gripper unit configured to, in a conveying cycle, pick up trays provided on the feed unit and convey them into the sealing station for a tray sealing process taking place in the sealing station as well as pick up packages produced within the sealing, station and convey them to the discharge unit, wherein the sealing station comprises a tool upper part, which includes a sealing tool, as well as a tool lower part, which includes a support plate, unit for depositing thereon the trays conveyed into the sealing station and a vertically adjustable tray holder for picking up and conveying the trays transferred to the support plate unit towards the tool upper part, the tray sealing machine additionally comprising a lifting mechanism configured to move the tray holder from a first position, at which the tray holder occupies a starting position in an open state of the sealing station, to a second position, at which the tray holder occupies a working position located closer to the tool upper part in a closed state of the sealing station, during a first predetermined motion sequence, the tray holder being adapted to be moved during the first motion sequence by means of the lifting mechanism in such a way that the tray holder will pick up the trays, which are provided on the support plate unit, at a predetermined pick-up speed, wherein the tray sealing machine is configured such that a rate of speed change over time of the tray holder will have changed from a positive value to a negative value during the first motion sequence before the tray holder has reached the predetermined pick-up speed.

17. A method of lifting and lowering a tray holder at a sealing station of a tray sealing machine, wherein, when the tray holder is being lifted, trays, which are provided on a support plate unit, are picked-up by means of the tray holder and conveyed to a tool upper part positioned above the tray holder, so as to carry out a tray sealing process, wherein the tray holder is moved by means of a lifting mechanism from a first position, at which the tray holder occupies a starting position in an open state of the sealing station, to a second position, at which the tray holder occupies a working position located closer to the tool upper part in a closed state of the sealing station, during a first predetermined motion sequence, wherein the tray holder picks up the trays, which are provided on the support plate unit, at a predetermined pick-up speed, wherein the rate of speed change over time of the tray holder changes from a positive value to a negative value during the first motion sequence before the tray holder reaches the predetermined pick-up speed.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present disclosure will be described on the basis of an embodiment in the following figures, in which

(2) FIG. 1 shows a tray sealing machine according to the present disclosure;

(3) FIG. 2A shows an open sealing station having the trays provided therein;

(4) FIG. 2B shows tray holder lifting relative to the stationarily arranged support plate unit;

(5) FIG. 2C shows trays carried along by the tray holder, so as to lift the trays for a sealing process;

(6) FIG. 2D shows tray lifting, by means of the tray holder towards the tool upper part of the sealing station arranged thereabove;

(7) FIG. 2E shows a representation of the sealing station in the closed state;

(8) FIG. 2F shows a representation of the sealing station daring the tray closing process for sealing the trays provided in the tray holder; and

(9) FIG. 3 shows a schematic motion sequence of the tray holder during closing and opening of the sealing station used on the tray sealing machine.

(10) The technical features shown in the figures are provided with like reference numerals throughout the application.

DETAILED DESCRIPTION

(11) FIG. 1 shows a tray sealing machine 1. The tray sealing machine 1 is configured as a so-called tray sealer. The tray sealing machine 1 comprises a feed unit 2 for conveying trays T in a production direction P, the trays T being shown e.g., in FIG. 2A. A sealing station 3 used for producing packages V is arranged downstream of the feed unit 2, when seen in the production direction P. The packages V are produced by a tray sealing process S according to FIG. 2F.

(12) In addition, FIG. 1 shows a discharge unit 4 arranged downstream of the sealing station. 3, When seen in the production direction P, and used for discharging the packages V produced. The tray sealing machine 1 according to FIG. 1 additionally comprises a gripper unit 5 configured for—in a conveying cycle—picking up trays T provided on the feed unit 2 and conveying them into the sealing station 3 for the tray sealing process S taking place in the latter. In addition, the gripper unit 5 is configured for picking up packages V produced within the sealing station 3 and for conveying them to the discharge unit 4. According to FIG. 1, the sealing station 3 has a tool upper part 6 as well as a tool lower part 7.

(13) FIG. 2A shows the sealing station 3 isolated from FIG. 1 in a schematic sectional view. The sealing station 3 is in an open state in FIG. 2A. The tool lower part 7 is positioned below the tool upper part 6 in spaced relationship therewith. The tool upper part 6 comprises a sealing tool 8. The tool lower part 7 provides a support plate unit 9, which is used for placing thereon the trays T conveyed into the sealing station 3. In addition, the tool lower part 7 comprises a tray holder 10 supported in a vertically adjustable manner and used for picking up and conveying the trays T deposited on the support plate unit 9 to the tool upper part 6 positioned thereabove.

(14) FIG. 2A additionally shows a lifting mechanism 11 configured for moving the tray holder 10 from a first position P1 shown in FIG. 2A to a second position P2, which will be described hereinafter in connection with FIGS. 2E and 2F. At the first position P1, the tray holder 10 is supported at a starting position in the open state of the sealing station 3. At the second position P2, the tray holder 10 occupies a working position located closer to the tool upper part 6 in the closed state of the sealing station 3. At the working position, an evacuation, gas flushing and/or sealing process can be carried out.

(15) In FIG. 2A, four trays T are arranged side by side or, when seen in the production direction P, one after the other on the support plate unit 9. The support plate unit 9 is provided with support plates 12, on which tray bases B of the respective trays T rest. The tray holder 10 is lifted by means of the lifting mechanism 11 and has reception units 13 receiving the tray edges R of the trays T provided. The tray holder 10 is lifted vertically along a direction Y to pick up the trays T provided.

(16) FIG. 2B shows the sealing station 3 with a tray holder 10 raised above its original level shown in FIG. 2A. In FIG. 2B, the respective reception units 13 have approached the tray edges R of the trays T. However, the individual trays T still rest on the respective support plates 12 of the support plate unit 9 with the tray bases 13 formed thereon.

(17) FIG. 2C shows the vertically adjustable tray holder 10 with trays T accommodated in the reception units 13 formed on the tray holder 10. The respective trays T now no longer rest on the support plate unit 9. FIG. 2D shows the tray holder 10 at a position raised still further, just before the sealing station 3 is closed,

(18) FIG. 2E shows the tray holder 10 at the second position P2, where the tray holder 10 occupies a working position located closer to the tool upper part 6 in the closed state of the sealing station 3. The sealing station 3 is now in a hermetically sealed state, so as to execute optionally an evacuation and/or a gas-flushing process within a chamber formed therein.

(19) The sealing tool 8 is lowered from the position shown in FIG. 2E to the position shown in FIG. 2F so as to close the trays T provided in the tray holder 10 by means of a top film, which is not shown, (tray sealing process S). In so doing, the top film is sealed, along the tray edges R, onto the trays T provided. Subsequently, the packages V are separated from one another within the sealing station 3.

(20) FIG. 2A to 2F show a closing process in the sealing station 3, the tray holder 10 being moved from the first position P1 up to and into the second position. P2, where the tray sealing process S can take place on trays accommodated in the sealing station 3. When the respective trays T provided by means of the tray holder 10 have been sealed, they are conveyed back to the support plate unit 9 by means of the tray holder 10. In so doing, the tray holder 10 returns to the first position P1, so that the gripper unit 5 shown in FIG. 1 can collect the sealed packages V, Which are placed on the support plate unit 9, and convey them to the discharge unit 4.

(21) FIG. 3 shows a motion sequence. A that can be used to lift and lower the tray holder 10 so as to close and open the sealing station 3. The motion sequence A comprises a first predetermined motion sequence A1, the velocity curve of which is used for illustrating the lifting of the tray holder 10 from the first position P1, at which the tray holder 10 occupies the starting position in an open state of the sealing station 3, to the second position P2, at which the tray holder 10 occupies the working position located closer to the tool upper part 6 in a closed state of the sealing station. Making use of the lifting mechanism 11, the tray holder 10 can be moved during the first motion sequence A1 such that the tray holder 10 will collect the trays 1, which have been provided on the support plate unit 9, at a predetermined pick-up speed v1 at a moment in time t1.

(22) FIG. 3 shows that the tray holder 10 is first accelerated during the motion sequence A1 up to an approach speed v2 and is then, when the approach speed v2 has been reached, decelerated down to the pick-up speed v1. The magnitude of the approach speed v2 exceeds that of the pick-up speed v1. In the course of the first motion sequence A1, the tray holder 10 is thus first accelerated up to a speed level above the pick-up speed v1 and then decelerated down to the pick-up speed v1 before the trays 71′ are received therein at the pick-up speed v1. In FIG. 3, during the first motion segment A1, local rate of speed change G over time changes, before the trays T are received by the tray holder 10, from a positive value to a negative value before the tray holder 10 has reached the predetermined pick-up speed v1.

(23) As soon as the trays T have been received by the tray holder 10, the tray holder 10 in FIG. 3 will move during a time, interval X1 at an almost constant speed, i.e., essentially at the pickup speed v1.

(24) In addition, FIG. 3 shows that, after the trays 1′ have been picked up, the tray holder 10 is, still during the first motion sequence A1, first accelerated and then decelerated, i.e., the rate of speed change G over time changes again from a positive value to a negative value before the tray holder 10 has arrived at the second position P2, i.e., the working position, at which the tray sealing process S takes place.

(25) According to FIG. 3, the tray sealing process S takes place within a predetermined time interval. After the tray sealing process S, the sealing station 3 is opened again. In so doing, the tray holder 10 is moved during the second predetermined motion sequence A2 from the second position P2 back to the first position P1 by means of the lifting mechanism 11.

(26) When the tray holder 10 is being lowered, the rate of speed change G over time of the tray holder 10 is changed from a negative value to a positive value during the second motion sequence A2 before the tray holder 10 has reached a predetermined depositing speed v4. FIG. 3 shows that the lifting and lowering of the tray holder 10 takes place in a substantially positionally symmetrical manner.

(27) Before the depositing speed v4 shown in FIG. 3 has been reached, the tray holder 10 has executed acceleration up to a maximum lowering speed v5, from which the tray holder 10 is decelerated down to the depositing speed v4. After having reached the depositing speed v4, the tray holder 10 is constantly advanced during a time interval X2 at the depositing speed v4, so as to gently deposit the produced packages V on the support plate unit 9. After having passed through the time interval X2, the tray holder 10 is accelerated again and then decelerated, so that it will return quickly to the first position P1. The packages V are then collected from the support plate unit 9 by means of the gripper unit 5 shown in FIG. 1 and transferred to the discharge unit 4. At the same time, the gripper unit 5 can deposit new trays on the support plate unit 9. Subsequently, conveyance of the trays is repeated according to motion sequence A, so as to produce new trays.

(28) The motion sequence A shown in FIG. 3 for the tray holder 10 of the sealing station 3 has the technical effect that the trays T can be picked up gently by means of the tray holder 10 and that the sealed packages V can also be deposited gently by means of the tray holder 10. The set motion sequence A also ensures rapid conveyance of the trays within the sealing station 3, so that the tray sealing machine 1 according to the present disclosure will be able to convey trays and sealed packages efficiently, i.e., within shorter conveying cycles.