IES20000561A2

IES20000561A2 - A transfer mechanism

Info

Publication number: IES20000561A2
Application number: IE20000561A
Authority: IE
Inventors: Martin O'malley; Gerard Patrick Kennedy
Original assignee: Bronway Res Ltd
Priority date: 2000-07-12
Filing date: 2000-07-12
Publication date: 2001-10-17
Also published as: IE20010809A1

Abstract

The invention concerns a transfer mechanism for picking-up an object at one location and placing it in another location comprising pick-up means for engaging and holding the object to be transferred, means for oscillating the pick-up means through an arc from the pick-up location to a place location, means for disengaging the object at the place location, and means to control the movement of the pick-up means. In one aspect, the mechanism comprises a main driven shaft, a number of spacer arms mounted on the main shaft, which support a second rotatable shaft which is disposed parallel to, and spaced from the main shaft. A number of pick-up devices are mounted on the second rotatable shaft. Control means, optionally comprising a belt and pulley arrangement is disposed between the main shaft and the second shaft to control the rotation of the second shaft. <Figure 1>

Description

The invention relates to a transfer mechanism for transferring objects from one location to another. In particular, the invention relates to a pick-and-place mechanism, that is a mechanism for picking up an object in one location and placing it in another. The invention has a number of applications. In one aspect, the invention is used in a machine for collating discs, especially Compact Discs (CD) and Digital Video Discs (DVD), which may be contained within sleeves, into sets and sub-sets. In another aspect, the pick-and-place mechanism may be used in a machine for placing discs within sleeves.

Background Art Repeatably picking a component and placing it at another location is a very common requirement in automation. This task is commonly accomplished using pneumatic actuators. The main disadvantage of this approach is that the actuator starts and stops suddenly causing vibration and wear. Only relatively light loads can be moved in this way satisfactorily Known transfer devices for use in collating discs, such as floppy discs, utilise mechanical pushing means and/or pneumatics for handling the discs. These known devices do not operate satisfactorily, and there is a need for a machine, for use, for example, in collating and sleeving CD discs, which will pick up a disc in one location and place it accurately in another.

Object of the Invention wrct T &(&ΰ> 1£>[<Ά | p bS ύ 3*7 I It is an object of the invention to provide a transfer mechanism for picking up an object, such as a disc, at one location and placing it in another in^«»fon. It L Lil.........“ OF£N TO PUBLIC SNSPECHON UNDER SECTION 28 AND RULE 23 inino.12£2_ IE000561 object of the invention to provide a machine for handling discs, such as CD discs. It is a further object of the invention to provide an improved collating machine which automates and simplifies the production of CD disc sets.

Summary of the Invention The invention provides transfer mechanism for picking-up an object at one location and placing it in another location comprising pick-up means for engaging and holding the object to be transferred, means for oscillating the pick-up means through an arc from the pick-up location to a place location, means for disengaging the object at the place location, and means to control the movement of the pick-up means.

In accordance with one aspect the invention comprises at least one arm or other connecting means, rotatable through an arc, means for rotating the arm, pick-up means pivotally mounted on the end of the arm, and means to control the pivoting movement of the pick-up means.

In one embodiment, the mechanism includes a main driven shaft, a plurality of spacer arms mounted on the main shaft and adapted to support a second rotatable shaft disposed parallel to, and spaced from the main shaft, a plurality of pick-up means mounted on the second rotatable shaft, and control means, optionally comprising a belt and pulley arrangement disposed between the main shaft and the second shaft to control the rotation of the second shaft. The ratio of the diameters of the pulleys determine the degree of rotation of the pick-up means during the oscillation of the second shaft.

Suitably, the drive means for oscillating the second shaft and pick-up means comprises an electric motor and includes a crank and link mechanism for converting the continuous rotation of the motor into an oscillation motion and transmitting said oscillation motion to the main shaft, spacer arms and vacuum arms.

IE000561 In accordance with another aspect, the invention provides a disc collating machine comprising disc feed means, transfer means for picking-up and transferring discs from the feed means to transport means, the transfer means comprising a plurality of pick-up means and means for oscillating the pick-up means through an arc from the feed means to the transport means.

Suitably, the feed means comprises a plurality of feed conveyors, and the transfer means comprises a main driven shaft, extending substantially at right angles to the direction of travel of the feed conveyors, a plurality of spacer arms mounted on the main shaft and adapted to support the pick-up means, and drive means for oscillating the arms through an arc from the feed means to the transport means.

The pick-up means may be carried on a second shaft which is carried by the spacer arms, the second shaft being rotatable, and control means are included to control the rotation of the shaft and the positioning of the pick-up means, said control means optionally comprising a belt and pulley arrangement disposed between the main shaft and the second shaft.

Suitably, the pick-up means comprises vacuum cups, but alternatively may comprise magnetic pick-up devices or mechanical gripping means. Preferably, the drive means for oscillating the second shaft and spacer arms comprises an electric motor and includes a crank and link mechanism for converting the continuous rotation of the motor into an oscillation motion and transmitting said oscillation motion to the main shaft, spacer arms and second shaft. Alternatively, a cam arrangement may be used.

Thus, the mechanism of the invention overcomes the disadvantages of the prior art by utilising the natural movement of a point on a circle as it rotates. When this motion is translated into linear motion via a link arm and subsequently back into a desired limit of circular motion using pulleys and belts of desired ratios, it ensures that the member (the main arm) which describes this desired limit of circular motion does so IE000561 in simple harmonic motion. This motion is very smooth having a natural and automatic acceleration/deceleration characteristic.

Brief Description of the Drawings An embodiment of the invention is hereinafter described with reference to the accompanying drawings, wherein: Figure 1 is a front elevation of one embodiment of a pick-and-place mechanism of the invention; Figure 2 shows the mechanism of Figure 1, at different stages in its operation; Figure 3 shows a modification of the device of Figure 1; Figure 4 is a schematic of control means for the transfer mechanism of the invention. Figure 5 is a front perspective view of a collating machine having a transfer mechanism according to the invention; Figure 6 is a front elevation of a collating machine similar to that of Figure 1 but with additional conveyors; Figure 7 is a left side elevation of the machine showing the transfer mechanism of the invention; Figure 8 is a right side elevation; Figure 9 is a detail of Figure 4, to an enlarged scale; and Figure 10 is a part-sectional detail, to an enlarged scale, of a vacuum cup connection.

Detailed Description Referring to Figures 1 and 2 of the drawings, this shows a first embodiment of a pick-and-place mechanism of the invention. The mechanism comprises a source of rotation, for example an electric motor 51, optionally including a gearbox, and which rotates continuously at constant velocity. A crank arm 34 is connected at one end to a rotor 33 of the motor 51, and is connected at the other end, by means of a pivot 35 to a link 36. The link 36 is pivotally connected, by a pivot 37, either directly to the periphery of an idler pulley 39 (as shown in Fig. 5) or to the idler pulley 39 by means of an arm 38 fixed to the pulley (as shown in Fig. 1). The operation of the crank IE000561 mechanism is illustrated in Figure 2, and it will be noted that it operates, to cause the pulley 39 to rotate first in one direction, and then as the linkage passes the dead point, to cause the pulley 39 to rotate in the opposite direction. This oscillating motion of the pulley 39 is transmitted by a belt 40 to a driven pulley 41 fixed to the end of a main shaft 20, which in turn transmits the motion to a main arm 23 which is caused to oscillate as shown in broken lines in Figure 9. It will be noted from Figure 1 that the arm 38 causes the pivot point 37 to describe an arc 52, thus causing pulley 39 to rotate through part of a circle. The size of the arc through which the pulley 39 rotates depends upon the distance between the centre of the circle being described by the arm 34 and its pivot point, in relation to the radius of the arc described by pivot 37. The maximum arc of oscillation of the arc 2 is about 165°. However, to maintain the forces acting on the connecting members to a minimum, it is preferred that the pulley 39 oscillate through an arc 52 of less than 90°. In order to provide for the oscillation of the arm 23, through an arc of more than 165°, e.g. example 170° to 180°, the second pulley 41 is used. The ratio of the pulleys 39 and 41 is selected, and is linear, to give the desired degree of movement of the arm 23.

The linkage of the invention ensures a smooth operation of the oscillation of the arm 23, so as to accelerate gently to normal working speed, and likewise to decelerate gently at the end of the operation.

A second embodiment is shown in Figure 3. In this embodiment the pulleys 39, and the belt 40 (of Figure 1) are replaced by gear wheels 71 and 72. The arm 38 is pivotally connected to the toothed gear wheel 71 which rotates in the same manner as pulley 39 of Figure 1. Gear 71 meshes with the toothed gear 72 which replaces the pulley 41 of the embodiment of Figure 1. Otherwise the two embodiments operate in the same manner, and like reference numerals are used to denote like parts. The ratio of the gears 71 and 72 is chosen to give the desired degree of oscillation.

As the arms 23 oscillate, as shown in Figures 1,2 and 5, a second shaft 25 is caused to rotate within bearings 24 on the ends of the arms 23. Means are provided to control the rotation of the second shaft 25, and to correctly position the vacuum cups 26.

These means, are located at the end of the second shaft 25 opposite to that on which the IE000561 main shaft drive means are located. The control means are shown in Figures 1 to 3 and schematically in Figure 4, and comprises a pulley 45 fixed to the end of the main horizontal shaft 20 and concentric therewith. A freely rotatable pulley 46 is journalled on the end of the second shaft 25. A toothed belt 47, which may be of nylon or the like, fits around the pulleys 45 and 46. As the arms 23 oscillate, as shown in Figure 4, the belt and pulley arrangement ensure that the vacuum cups are all correctly positioned, with the vacuum cups facing downwardly. The ratio of the diameters (or teeth) of the pulleys 45, 46 is important to control the range of movement of the pick-up mechanism i.e. the vacuum cups 26. The degree of parallelism of the axis of the vacuum cup can be predetermined by altering the ratio of the pulleys 45, 46. For example, when the vacuum cup 26 is in the pick position, as shown to the left of Figure 9, the plane of the pick-up end of the vacuum cup is at about 15° to the horizontal, so as to coincide with the angle of repose of the discs to be picked-up. As the vacuum cups travels, through an arc, from the left to the right of Figure 9, the angle is changed by the belt 47, until when the vacuum cup 26 reaches the end of its arc of oscillation the plane of the bottom end of the vacuum cup is substantially horizontal, i.e. it is disposed parallel to the surface of the transport conveyor 4.

A transfer mechanism of the invention used in a disc collating machine is shown in Figures 5 to 10. The collator comprises disc feed conveyors 1, transfer means 2 for picking-up discs 3, and transferring the discs 3 through an arc of predetermined size, for example from about 170° to 180°, onto a transport conveyor 4. A delivery conveyor 5, is provided, at the side of the machine, for delivering collated sets of discs from the transport conveyor, to packing means. The collator has a control panel 6. The machine is mounted on a suitable frame 7 having feet 8.

As shown in Figures 5 and 6, there are a plurality of feed conveyors 1, arranged side by side and parallel to each other. The direction of travel of the conveyors 1 is substantially at right angles to the transfer means 2. In the embodiment shown in Figure 1 there are eight feed conveyors 1, arranged side by side, while in the embodiment of Figure 2 there are sixteen conveyors 1. As shown in Figure 8, each of the feed conveyors 1 comprises an endless belt 10 which travels about a pair of spaced rollers 11, IE000561 12. The inner roller 12 is driven by an electric motor 13, through a drive belt 14 (see Fig. 5) to a pulley 15 fixed on the conveyor drive shaft 16, which is keyed to the rollers 12. Each of the feed conveyors 1 has its own individual drive means, including individual motors 13, gearboxes and drive belts 14. Each endless belt 10 may comprise a single belt or (as shown in the drawings) may consist of a plurality of flexible cords. Upstanding guide walls 17 are disposed one to each side of the feed conveyors 1.

The transfer means 2 of the invention is now described with reference to Figures 1,4 and 8 to 10. It comprises a main shaft 20, which extends transversely of the machine substantially at right angles to the direction of travel of the feed conveyors 2.

It is mounted for rotation in bearings 21 located at each side of the machine.

Intermediate bearings 22 (see Fig. 1) may also be provided. A pair of spacer arms 23 are fixed, one at each end to the shaft 20. Intermediate spacer arms 23 may be provided as required.

The inner ends of the arms 23 are fixed to the main shaft 20, whereas the outer ends of the arms 23 include a bearing 24 in which a second shaft 25 is rotatable. The second shaft 25 extends transversely of the machine parallel to the main shaft 20, but spaced therefrom by the arms 23.

As shown in broken lines in Figure 9, the arms 23, together with the second shaft 25, are caused to oscillate, through a predetermined angle, e.g. an angle of about 170° or 180°, from the feed conveyors 1 to the transport conveyor 4, by means of the eccentric crank and link mechanism as described in more detail above with reference to Figures 1 to 4.

A plurality of vacuum cups 26 are mounted at spaced intervals along the second shaft 25. The means for mounting the cups 26 on the shaft 25 is shown in more detail in Figure 6, and comprises a bracket 27 having two split parts which fix around that shaft 25. The bracket 27 is tightened on the shaft 25 by screws 28. The machine includes a vacuum pump (not shown) to apply vacuum to the vacuum cups 26 in well known manner. The vacuum pump is connected to the vacuum cups through the hollow IE000561 interior of the shaft 25, which has a plurality of air passages 29 connected to air channels 30. The air channels 30 are fitted with flow restrictors 31. The vacuum cup 26 may be made from rubber or other flexible material, in well known manner. In Figure 6, the bracket 27 is shown as supporting a single vacuum cup 26. Alternatively, each bracket 27 may support a pair of vacuum cups 26. The vacuum cup 26 (or pair of cups) are each positioned on the second shaft 25 so that they are aligned with a respective feed conveyor.

The means for oscillating the spacer arms 23 and second shaft 25, and the means for controlling the rotation are described above with reference to Figures 1 to 4. Figure 2 shows schematically the link and crank mechanism which converts continuous rotation, from the drive motor 32 into oscillation of the arms 23 with a variable velocity ratio.

As shown in Figures 7 to 9, the transport conveyor 4 is positioned directly behind the transfer means 4. It is a single conveyor and travels in a direction parallel to the main shaft 20, that is at right angles to the direction of travel of the feed conveyors 1. The transport conveyor 4 comprises an endless belt 60, consisting of a number of discrete flexible cords, which travel about a pair of rollers 61, 62 which are located one at each opposite end of the conveyor. The roller 61 is driven by an electric motor 63.

The operation of the collator is now described.

Each of the feed conveyors 1 holds between from about 100 to 150 CD sleeves, depending on their thickness. Before starting the collator a selected number of feed conveyors 1 is loaded with disc sleeves depending upon the size of the set it is desired to achieve. In this context the term “set” refers to a number of different disc sleeves 3 collated together to form a single group. A “batch” refers to a plurality of collated sets, that is several collated sets make up a single batch.

If, for example, it is desired to collate one hundred sets of disc sleeves, each set to contain six different discs 3, then one hundred of each disc 3 are loaded onto the first IE000561 six of the feed conveyors 1. Each bundle of discs 3 are loaded so that they lie forward and are spread out (shingled) so that the top surface of the bundle is approximately at the same level as the guide walls 17. The machine is then started. The feed conveyor 1 feeds the discs 3 towards the pick-up point. The vacuum pump is turned on. At the pick-up point (see Fig. 5) the arms 23 and vacuum cups 26 pick one disc 3 from each of the “active” feed conveyors 1 (in this case the first six), conveys them through an arc of about 180° and places them on the transport conveyor 4. The collator includes sensors to activate the vacuum at the start of the transfer cycle and to deactivate the vacuum at the end of the cycle to enable the disc 3 to be dropped onto the transport conveyor 4. A sensor is also provided to activate the transport conveyor 4 as each set of discs 3 is deposited on the conveyor. The transport conveyor 4 delivers each set of discs to the delivery conveyor 5, which extends at right angles to the transport conveyor 4. The delivery conveyor 5 is provided with a number of partitions (or slats) and each set of collated discs is passed by the transport conveyor 4 to a partitioned location on the delivery conveyor 5. In this way the sets of discs 3 can conveniently be formed into bundles. The arms 23 continue to oscillate to pick-up and transfer the discs to the transport conveyor until all of the discs have been collated.

The collator includes control means, e.g. a dedicated controller or a programmable logic controller (PLC) for controlling the various functions of the collator. The control panel 6 enables the operator to initiate the various functions, including starting, stopping and setting-up of collating tasks. The control panel 6 has an LCD display, a numeric keypad, a “clear” key, and “enter” key, a start button, a stop button and an emergency stop button.

The LCD display indicates the collation statistics during normal operation.

When the collation parameters are set up, the display will prompt the operator to enter the data required. The display also indicates errors in clear text if they occur. The numeric keypad allows entry of numeric values, for example set size, number of sets and so on. The numeric keys 0 to 9 are present. Selected keys allow entry into programming mode, and may be used to toggle up or down through the menu parameters when in programming mode, to enter numeric values, or to initiate selected IE000561 ίο functions. The enter key is used to set a selected parameter value keyed in during parameter set-up. It also allows a move to the next parameter option during set-up. The start button is used to commence collation having set up the collation parameters. The stop button is used to halt the collation process, for example during magazine reloading or to clear a jam of disc sleeves should one occur. The emergency stop button allows shutting off the machine completely and instantaneously. This would be used if, for example, a foreign object became jammed in the collator.

The collator embodying transfer means of the invention has a number of advantages. It has a high speed operation, and can collate and assemble a set of eight disc sleeves in approximately four seconds, that is about fifteen sets per minute, or 7,200 disc sleeves per hour. The embodiment containing sixteen feed conveyors can produce a full set of sixteen CD sleeves in about six seconds, or about 9,600 CD sleeves per hour. The feed conveyors may be reloaded while the machine is in operation. The machine of the invention substantially reduces labour costs, and reduces manual handling of the disc sleeves, which also has a cosmetic improvement. It improves product integrity.

IE000561

Claims

1. A transfer mechanism for picking-up an object at one location and placing it in another location comprising pick-up means for engaging and holding the object to be transferred, means for oscillating the pick-up means through an arc from the pick-up location to a place location, means for disengaging the object at the place location, and means to control the movement of the pick-up means.

2. A transfer mechanism as claimed in claim 1, comprising at least one arm or other connecting means, rotatable through an arc, means for rotating the arm, pick-up means pivotally mounted on the end of the arm, and means to control the pivoting movement of the pick-up means.

3. A mechanism as claimed in claim 1 or 2, comprising a main driven shaft, a plurality of spacer arms mounted on the main shaft and adapted to support a second rotatable shaft disposed parallel to, and spaced from the main shaft, a plurality of pickup means mounted on the second rotatable shaft, and control means, optionally comprising a belt and pulley arrangement disposed between the main shaft and the second shaft to control the rotation of the second shaft.

4. A mechanism as claimed in any of claims 1 to 3, wherein drive means for oscillating the second shaft and pick-up means comprises an electric motor and includes a crank and link mechanism for converting the continuous rotation of the motor into an oscillation motion and transmitting said oscillation motion to the main shaft, spacer arms and vacuum arms.

5. A collating machine for collating discs and the like comprises feed means, transfer means as claimed in any of claims 1 to 4 for picking-up and transferring discs from the feed means to transport means, and optionally the feed means comprises a plurality of feed conveyors, and the transfer means comprises a main driven shaft, extending substantially at right angles to the direction of travel of the feed conveyors, a plurality of spacer arms mounted on the main shaft and adapted to support the pick-up IE000561 means, optionally in the form of the vacuum cups, and drive means for oscillating the arms through an arc from the feed means to the transport means.

6. A transfer mechanism substantially as hereinbefore described with reference to, 5 and as illustrated in, one or more of the accompanying drawings.