DRIVE UNIT

Abstract

A drive unit for driving a carriage which can be displaced along a transporting path comprises a barrel cam, which can be driven to rotate and has a drive groove for engagement of a driver arranged on the carriage, and also comprises a control device for controlling the drive of the carriage. The barrel cam has a first barrel portion and a second barrel portion, which is separate from the first, wherein the barrel portions can be driven independently of one another, and wherein the control device is designed so that, once the carriage has been received from a separate drive unit, it can accelerate the carriage by means of the first barrel portion and can supply the accelerated carriage to the second barrel portion.

Claims

1-21. (canceled)

22. A drive unit for driving a carriage travelable along a transport path, the drive unit having a barrel cam, with the barrel cam being drivable to make a rotational movement and the barrel cam having a drive groove for an engagement of a follower arranged at the carriage, the drive unit further having a control device for controlling the drive of the carriage, wherein the barrel cam has a first barrel section and a second barrel section separate from the first barrel section, with the first and second barrel sections being drivable independently of one another, and with the control device being configured to accelerate the carriage after a takeover from a separate drive unit by means of the first barrel section and to supply the accelerated carriage to the second barrel section.

23. The drive unit in accordance with claim 22, wherein the second barrel section directly adjoins the first barrel section.

24. The drive unit in accordance with claim 22, wherein the first and second barrel sections are arranged coaxially to one another.

25. The drive unit in accordance with claim 22, wherein the drive groove has a section in the region of the first barrel section, with the section extending spirally and over an angle of rotation of at most 180 .

26. The drive unit in accordance with claim 22, wherein the drive groove has an introduction region at an inlet side of the barrel cam in the region of the first barrel section, said introduction region extending in parallel with at least one of a direction of transport of the carriage and an axis of rotation of the barrel cam.

27. The drive unit in accordance with claim 22, wherein the drive groove has a discharge region in a region of the first barrel section adjacent to the second barrel section, in which discharge region a pitch of the drive groove relative to an axis of rotation of the barrel cam corresponds to a pitch of the drive groove in an adjacent section of the second barrel section.

28. The drive unit in accordance with claim 22, wherein means are provided for determining an instantaneous speed of rotation of the second barrel section and, optionally, of the first barrel section, with the control device being configured to accelerate the first barrel section after a takeover of the carriage from a starting speed of rotation to an end speed of rotation which corresponds to the instantaneous speed of rotation of the second barrel section.

29. The drive unit in accordance with claim 22, wherein the control device is configured to drive the second barrel section to make a rotational movement at a constant speed of rotation.

30. The drive unit in accordance with claim 22, wherein means are provided for detecting an instantaneous rotational position of the first barrel section, with the control device being configured to move the first barrel section into a predefined rotational position after a supply of the carriage to the second barrel section for a takeover of a subsequent carriage.

31. The drive unit in accordance with claim 22, wherein the drive groove comprises a straight section extending in parallel with at least one of a direction of transport (T) and an axis of rotation (D) of the barrel cam and wherein the drive groove comprises a spirally extending section adjoining the straight section in the region of the first barrel section.

32. The drive unit in accordance with claim 31, wherein the control device is configured to drive the first barrel section to make a rotational movement which accelerates the carriage as soon as the follower of a taken-over carriage has moved from the straight section into the spirally extending section.

33. The drive unit in accordance with claim 22, wherein the drive groove of the second barrel section has a constant pitch.

34. A method of transporting objects along a transport path in which a carriage which is travelable along the transport path and on which at least one object is to be arranged is moved from a transfer section of the transport path onto a process section of the transport path provided for a machining of the objects, wherein the carriage is driven in the process section by means of a first barrel cam which is drivable to make a rotational movement and which has a drive groove into which a follower arranged at the carriage engages; and wherein the carriage is driven to make a movement in the transfer section by means of a separate drive, wherein the carriage is accelerated by means of a second barrel cam drivable independently of the first barrel cam to move from the transfer section to the process section.

35. The method in accordance with claim 34, wherein an instantaneous speed of rotation of the first barrel cam is determined and the second barrel cam is accelerated after a takeover of the carriage from a starting speed of rotation which preferably amounts to zero to an end speed of rotation which corresponds to the instantaneous speed of rotation of the first barrel cam.

36. The method in accordance with claim 34, wherein the first barrel cam is driven to make a rotational movement at a constant speed of rotation; and/or wherein the drive groove of the second barrel cam has a constant pitch.

37. The method in accordance with claim 34, wherein an instantaneous rotational position of the second barrel cam is detected and the second barrel cam is rotated into a predefined rotational position after a supply of the accelerated carriage to the first barrel cam for a takeover of a subsequent carriage.

38. The method in accordance with claims 34, wherein the second barrel cam is driven to make a rotational movement accelerating the carriage as soon as the follower of the carriage has moved from a straight section of a drive groove of the second barrel cam extending in parallel with a direction of transport and/or in parallel with an axis of rotation of the second barrel cam into a spirally extending section of the drive groove adjoining it.

39. A transport apparatus for transporting objects along a transport path, having at least one carriage which is travelable along the transport path and which is configured for receiving at least one object to be transported; and having means for the controlled driving of the carriage, wherein the transport path comprises at least one process section provided for a machining of the objects and at least one transfer section separate therefrom; wherein a drive unit having at least one barrel cam drivable to make a rotational movement is provided for driving the carriage in the process section, said barrel cam having a drive groove into which a follower arranged at the carriage engages; and wherein a linear motor having at least one fixed-position stator element and a runner element arranged at the carriage is provided for driving the carriage in the transfer section.

40. The transport apparatus in accordance with claim 39, wherein the drive unit is configured as a drive unit for driving the carriage travelable along a transport path, the drive unit having the barrel cam, with the barrel cam being drivable to make a rotational movement and the barrel cam having a drive groove for an engagement of a follower arranged at the carriage, the drive unit further having a control device for controlling the drive of the carriage, wherein the barrel cam has a first barrel section and a second barrel section separate from the first barrel section, with the first and second barrel sections being drivable independently of one another, and with the control device being configured to accelerate the carriage after a takeover from a separate drive unit by means of the first barrel section and to supply the accelerated carriage to the second barrel section.

41. The transport apparatus in accordance with claim 39, further comprising a control device which is configured to carry out a method of transporting objects along the transport path in which the carriage which is travelable along the transport path and on which the least one object to be arranged is moved from the transfer section of the transport path onto the process section of the transport path provided for the machining of the objects, wherein the carriage is driven in the process section by means of the first barrel cam which is drivable to make a rotational movement and which has the drive groove into which a follower arranged at the carriage engages; and wherein the carriage is driven to make a movement in the transfer section by means of a separate drive, wherein the carriage is accelerated by means of a second barrel cam drivable independently of the first barrel cam to move from the transfer section to the process section.

42. The transport apparatus in accordance with claim 39, wherein the transport path is an at least substantially circular path.

Description

[0034] FIG. 1 is a simplified plan view of a transport apparatus in accordance with the invention for transporting objects along a transport path;

[0035] FIG. 2 is a perspective view of a drive unit of the transport apparatus shown in FIG. 1;

[0036] FIG. 3 is a partial plan view of the drive unit in accordance with FIG. 2;

[0037] FIG. 4 is a perspective view of a barrel cam of the drive unit shown in FIG. 2;

[0038] FIG. 5A shows the barrel cam in accordance with FIG. 4 in a plan view; and

[0039] FIG. 5B shows the barrel cam in accordance with FIG. 4 in a side view.

[0040] The transport apparatus 10 shown in FIG. 1 serves for the transport of objects, not shown, and comprises a rail 12 which defines a closed transport path along which the objectse.g. workpiecesare transported. It is understood that the transport path could also be open and/or could have a different, e.g. more complex, extent. The transport path can also form a circle so that ultimately a rotary indexing table is implementedviewed from a functional aspectin which objects can be moved independently of one another.

[0041] A plurality of carriages 14 are guided at the rail 12 in a slidingly or rollingly travelable manner. The objects to be transported are arranged on a transport platform, not shown, of the carriages 14 and are traveled along the transport path with them. The transport path in the example shown is divided into two process sections 16A, 16B provided for a machining of the objects and indicated by dashed lines and into two transfer sections 18A, 18B respectively disposed therebetween. Depending on the application, the transport path can have any desired number of process sections 16A, 16B and transfer sections 18A, 18B.

[0042] The drive of the carriages 14 is based on a combination of two basically different drive systems. The drive of the carriages 14 in the two transfer sections 18A, 18B takes place by means of a linear motor arrangement, not shown, which comprises in a generally known manner fixed-position stator elements which are arranged along the rail 12 and respective runner elements which are arranged at the carriages 14. The carriages 14 can be traveled by means of the linear motor arrangement at a high speed between the process sections 16A, 16B. An electronic control unit, which is not shown in FIG. 1, is provided for controlling the linear motor arrangement.

[0043] The drive of the carriages 14 in the two process sections 16A, 16B does not take place by means of a linear motor, but rather by means of respective drive units 20A, 20B which have barrel cams drivable to make a rotational movement, as will be explained in more detail in the following with reference to FIGS. 2 to 5.

[0044] Each of the two drive units 20A, 20B comprises a barrel cam 22 which is drivable to make a rotational movement about an axis of rotation D by means of a motor arrangement 24. The barrel cam 22 comprises a drive groove 26.

[0045] The drive units 20A, 20B are each arranged next to the rail 12 (FIG. 1) such that followers, not shown, provided at the carriages 14 engage into the drive groove 26 when the corresponding carriage 14 enters into the associated process section 16A, 16B. Due to the cooperation of the drive groove 26 and the follower, the respective carriage 14 is moved in a direction of transport T extending in parallel with the axis of rotation D. Such a drive of a travelable carriage 14 by means of a barrel cam 22 drivenas requiredto make a uniform or a time-varying rotational movement is generally known and allows a high positioning accuracy which is significant for the machining of the objects arranged on the carriage 14 in the process sections 16A, 16B

[0046] To facilitate the transfer of the carriages 14 from a transfer section 18A, 18B into the process section 16A, 16B adjoining it, the barrel cam 22 is divided into two separate coaxial barrel sections 30A, 30B. The drive groove 26 is designed as substantially spiral in the region of the barrel section 30B. It can, however, generally have one or more latch threads and/or sections having different pitches. The barrel sections 30A, 30B are drivable independently of one another by means of respective single motor units 32A, 32B of the motor arrangement 24 and of associated transmission units 34A, 34B.

[0047] As can be seen from FIGS. 2 and 3, the first barrel section 30A at the front with respect to the direction of transport T is substantially shorter than the second barrel section 30B. The first barrel section 30A can therefore be rotatably supported on a shaft of the second barrel section 30B which acts in this respect as a total shaft of the barrel cam 22.

[0048] While the drive groove 26 in the present exampleas already explainedhas a constant pitch in the region of the second barrel section 30B, it comprises a straight section 40 extending in parallel with the direction of transport T and in parallel with the axis of rotation D of the barrel cam 40 and a spirally extending section 42 adjoining it in the region of the first cam section 30A. The spirally extending section 42 has a pitch which corresponds to the pitch of the drive groove 25 in the inlet region of the second barrel section 30B and it extends over an angle of rotation which amounts to between 90 and 180 here.

[0049] Respective sensors, not shown, are provided at the drive units 20A, 20B to detect the speeds of rotation and the instantaneous rotational positions of the barrel sections 30A, 30B. The sensors are in signal connection with a control device. The control device associated with the drive units 20A, 20B and the control unit of the linear motor arrangement preferably form a common control.

[0050] During the operation of the transport apparatus 10, carriages 14 having objects arranged thereon are consecutively taken over by the drive units 20A, 20B from the transfer section 18A, 18B preceding with respect to the direction of transport T. The control device provides that the second barrel section 30B is driven to make a rotational movement at a speed of rotation adapted to the corresponding process section 16A, 16B to generate a desired movement profile of the carriages 14 in this region. The first barrel section 30A is stationary for the takeover of the carriages 14, with the straight section 40 of the drive groove 26 facing upward, as shown in FIGS. 2 and 3. A follower provided at the lower side of an arriving carriage 14 can thus engage in a jerk-free manner and as a result of the movement effected by the linear motor arrangement of the transfer section 18A, 18B into the section 40 of the drive groove 26. As soon as the follower of a carriage 14 taken over in this manner has moved from the straight section 40 into the spirally extending section 42, the first barrel section 30A is driven to make a rotational movement. The rotational movement is accelerated until the speed of rotation of the first barrel section 30A corresponds to the speed of rotation of the second barrel section 30B and an outlet region of the section 42 and an inlet region of the part of the drive groove 26 provided at the barrel section 30B merge into one another. In other words, the section 30A is accelerated until a synchronization of the sections 30A, 30B has been achieved. The follower of the carriage 14 accelerated in this manner then moves in a jerk-free manner into the second barrel section 30B and is transported by it along the direction of transport T. It is understood that the second barrel section 30B can simultaneously transport a plurality of carriages 14 in dependence on its length and on the dimensions of the carriages 14, if this is desired.

[0051] As soon as the carriage 14 has been supplied to the second barrel section 30B, the control device provides that the first barrel section 30A is again moved into the reception rotational position shown in FIGS. 2 and 3 for a takeover of a following carriage 14.

[0052] Due to the configuration of the drive units 20A, 20B, which can also be designed differently, with a plurality of separate barrel sections 30A, 30B which can be driven independently of one another and due to the combined drive by means of the drive units 20A, 20B, on the one hand, and the linear motor arrangement, on the other hand, a particularly high throughput can be achieved in the machining of consecutively transported objects.

REFERENCE NUMERAL LIST

[0053] 10 transport apparatus [0054] 12 rail [0055] 14 carriage [0056] 16A, 16B process section [0057] 18A, 18B transfer section [0058] 20A, 20B drive unit [0059] 22 barrel cam [0060] 24 motor arrangement [0061] 26 drive groove [0062] 30A first barrel section [0063] 30B second barrel section [0064] 32A, 32B single motor unit [0065] 34A, 34B transmission unit [0066] 40 straight section [0067] 42 spirally extending section [0068] D axis of rotation [0069] T direction of transport