GB1588059A

GB1588059A - Transferring workpieces to or from a rotary table

Info

Publication number: GB1588059A
Application number: GB5105277A
Authority: GB
Original assignee: KUMETH S
Current assignee: KUMETH S
Priority date: 1977-12-08
Filing date: 1977-12-08
Publication date: 1981-04-15

Description

(54) TRANSFERRING WORKPIECES TO OR FROM A ROTARY TABLE (71) I, SIEGMUND KUMETH, a citizen of the German Federal Republic of Schlottstr.

3, 8450 Amberg, German Federal Republic, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement:- The invention relates to transferring workpieces to or from a rotary table, and is applicable to fabrication finishing or assembly apparatus. In particular the invention relates to transferring a workpiece or component from a pick-up station to a corresponding reception station, on a rotary indexed table, by means of a handling device.

Such fabrication, fipishing or assembly apparatus may serve, for example, to further process workpieces delivered to the pick-up station by a device e.g. conveyor belt, chute etc. or to produce an end product by assembling workpieces or components. In the latter case there will usually be a plurality of transfer mechanism pick-up stations from which the workpieces or components delivered thereto are transferred by a handling device to the reception station. These workpieces or components can then be further processed or can be assembled with other workpieces or components which have already been transferred to the reception station at a previous pick-up station.

A disadvantage of known such apparatus is that, in bringing the workpiece or component to the reception station, the handling device must carry out a relatively complicated movement in several space axes, so that the operation and the controlling of the apparatus is extremely complicated.

An object of the invention is to produce apparatus which avoids this disadvantage.

According to the present invention there is provided apparatus comprising a rotary table movable stepwise about a vertical axis and having a plurality of receiving stations spaced about its periphery, at least one transfer mechanism for transporting workpieces to or from the apparatus, and a handling device operable for transferring a workpiece from a transfer mechanism terminal to a rotary table receiving station or for transferring a workpiece from a rotary table receiving station to the transfer mechanism terminal, characterised in that the rotary table has recesses interposed between said receiving stations, the transfer mechanism terminal is disposed below the path of movement of the rotary table receiving stations and the handling device is movable only along a vertical axis intersecting the transfer mechanism terminal and the path of movement of the rotary table receiving station, in transferring the workpiece therebetween.

Preferably the spacing between neighbouring receiving stations corresponds to two movement steps of the rotary table.

Then the handling device and rotary table may cooperate such that for transferring a workpiece from the transfer mechanism terminal to a rotary table receiving station the handling device moves firstly from a first position above the rotary table through a recess between two neighbouring rotary table receiving stations to pick-up the workpiece from the transfer mechanism terminal below the path of movement of said receiving stations, then returns to a position above the path of movement of said receiving station from whence the device is again moved towards the rotary table for depositing the workpiece on a rotary table receiving station, the rotary table performing one movement step between the return and deposition movements of the handling device.

For transferring a workpiece from a rotary table receiving station to the transfer mechanism terminal, the arrangement may be such that, firstly, the handling device moves from a first position above the rotary table to pick up a workpiece from a rotary table receiving station, returns to a position above the rotary table, and then moves through a rotary table recess to the subjacent transfer mechanism terminal for depositing the workpiece on said terminal, the rotary table performing one movement step, between the return and deposition movements of the handling device.

The reception stations may comprise inte gral parts of the rotary table, or be formed by parts fastened to an upper surface of this rotary table and projecting beyond its periphery. The spaces or recesses provided between the individual reception stations result in the rotary table (inclusive, where applicable, of the parts forming the reception stations) having at the reception stations a greater diameter or radius than in the region between two neighbouring reception stations.

One embodiment of the invention is described in more detail below by way of example and with reference to the drawings in which: Figure 1 is a schematic illustration of a side elevation of fabricating, finishing or assembly apparatus according to the invention.

Figure 2 is a schematic plan view of the apparatus according to Figure 1 and with handling devices omitted.

Figure 3 is a perspective view of a work piece produced with the apparatus according to Figure 1; Figure 4 is a sectional view of the drive for the rotary table carrying the reception stations, as well as for the handling devices in the apparatus according to Figure 1; Figure 5 is a detail of the drive for lifting and lowering the handling devices; Figure 6 a detail of the drive for the rotary table, and Figure 7 is a detailed sectional view of a handling device.

The fabrication, finishing or assembly apparatus shown in the drawings consists of a fixed housing part 1, which contains the driving mechanism, on the upper side of which is rotatably mounted a disc-shaped rotary table 2, which by means of the drive mechanism is rotated stepwise about a vertical axis A. A number of lugs 3 are fastened to the outer periphery of the rotary table 2 which project above the peripheral surface of the rotary table 2 and have a mutual spacing from one another which is double the movement of the rotary table in a working step. In the illustration of Figure 2 the rotary table 2 is moved by the driving device stepwise in the clockwise direction, that is to say in the direction of the arrow B, so that the lugs 3 occupy working positions I to V (Figure 2), successively, after alternate movement steps.

The lugs 3 form on their surface remote from the housing part 1 reception stations 4 for the workpieces or for component parts for the production of the workpieces.

The illustrated embodiment of apparatus according to the invention, is used to assemble a workpiece as illustrated in Figure 3, which is an electrical resistance, consisting of a carrier body 5 with a layer of electrically conducting material (for example, a carbon layer) and soldering lugs 7 fastened to the ends of this body by rivets 6. Such resistances are used, for example, for the production of electrical slide-potentiometers.

In the assembly of such a resistance by the indicated fabricating, finishing or assembly apparatus a first device 8 delivers the rivets 6 from a magazine, not shown in detail, to the rotary table 2, at working position I. The rivets 6 are then taken off the device 8 by means of a handling device 9, and set down on a fixing pin 10 (see Figures 2 and 7) on the upper side of the lug 3 or on the reception station surface 4 in such a way that the rivets 6 rest with their enlarged head part on the reception surface 4 and embrace the fixing pin 10.

Since one rivet 6 is required for fastening each soldering lug 7, two fixing pins 10 are arranged spaced apart on the reception surface 4, which spacing corresponds to the spacing of the soldering lugs 7 or the spacing of the bores in the carrier body 5 for the rivets 6.

As indicated in Figure 2 two rivet conveyor devices 8 are provided with the fabricating or assembly apparatus, so that in working position I, a rivet 6 from the first device 8 is positioned on one fixing pin 10 by means of the handling device 9 provided at that working position and in working position II of the rotary table 2, a rivet 6 from the second device 8 is set down on the other fixing pin 10 by means of a second handling device 9, at the second position. A carrier body 5 with bores prepared for the rivets 6 is delivered to working position III of the rotary table 2, by means of a second conveyor 11, and by the handling device 9 provided there, is taken off the conveyor 11 and set down on the rivets 6 carried by the fixing pins 10.In the working positions IV and V there then takes place in similar manner the depositing of the soldering lugs 7 and, if desired, the riveting of these soldering lugs to the carrier body 5.

The handling device 9 provided at each working position I-V consists of gripping tongs 13, which can, for example, be opened or closed hydraulically or pneumatically, and which are fastened to a carrier beam 14 in such a way, that these tongs 13 lie exactly over the fixing pins 10 or over the removal position of the conveyor devices 8, 11 or 12.

The carrier beam 14 of each handling device 9 is displaceably guided in the vertical direction or in the direction of the axis A on two pillars 15 and 16, and, by means of a rod 17 which can be moved up and down from the rest position shown in Figure 1, can be lowered, to a first operative position, in which the tongs 13 with their two oppositely pivotable parts 13' and 13" can grasp a rivet 6, a carrier body 5 or a soldering lug 7 from the corresponding conveyor device 8, 11 or 12 at a pick-up position below the lugs 3.

The carrier beam//14 and therewith the tongs 13 can be 4towered from the rest position indicatedam Figure 1 with a smaller working stroke into a second operative position, in which the rivets 6, carrier body 5 or soldering lugs 7 can be deposited from the gripping tongs 13 onto the fixing pins 10, at the reception station.

Pillars 15 and 16 serving as guides for the carrier beams 14 are fastened on a first stationary plate 18, which is arranged above the rotary table 2 and has a smaller diameter than this rotary table. In order to be able to actuate a plurality of carrier beams 14 with a single rod 17, this has at its upper end a plate shaped extension 17', on which rest the ends remote from the gripping tongs 13 of the carrier beams 14 of the individual handling devices 9.The fundamental method of operation of the fabricating, finishing or assembly device is as follows; It is assumed that the rotary table 2 is in a position in which none of the reception stations 4 or lugs 3 are in one of the working positions I-V, that is to say the lugs 3 are in intermediate positions between the working positions I-V or between the conveyor devices 8, 11, and 12 as indicated in Figure 2 by chain lines between working positions III and IV.

The carrier beams 14 together with handling devices 9 with opened tong halves 13' and 13" are now lowered by means of rod 17 towards the first working position and on reaching this the tongs 13 are closed so that the tongs of each handling device 9 grasp either a rivet 6, a carrier body 5 or a soldering lug 7.

The carrier beams 14 and their tongs 13 are now returned to the rest position shown in Figure 1 by means of rod 17. Following that the rotary table 2 is rotated through one step in the direction of the arrow B so that each lug 3 fastened on the outer periphery of the rotary table reaches a corresponding one of the working positions I-V. The carrier beams 14 with their tongs 13 are lowered by rod 17 into the second working position and the rivets 6, the carrier bodies 5 and the soldering lugs 7 then deposited onto the fixing pins 10 or the rivets 6 already provided on these pins. The tong halves 13' and 13" are again opened and by means of rod 19 the handling devices are returned to the rest position shown in Figure 1.

There next follows a rotation of the rotary table 2 through one step, so that the lugs 3 are again between the working positions I V. By repeated lowering of the handling devices into the first working position further rivets 6, carrier bodies 5 or soldering lugs 7 delivered by the conveyor devices 8, 11 and 12 respectively are grasped by the tongs 13, which then, in the manner described, by lifting up the handling devices, further movement of the rotary table 2 through one step and lowering of the handling devices 9, are set down at the reception station 4 or onto the fixing pins 10 as required.

It should noted that the handling devices 9 for the removal of the individual parts (rivets 6, carrier bodies 5 and soldering lugs 7) from the conveyor devices 8, 11 and 12 as well as for depositing these parts onto the reception stations 4 of the lugs 3, carry out a movement in only one individual plane perpendicular to the surface of the rotary table 2, namely in the direction of the axis A, (Figure 1) and furthermore the handling devices 9, after each further stepping of the rotary table 2, either carry out a large working stroke from the rest position into the first working position and back or a small working stroke from the rest position into the second working position and back.

The necessary control or driving means for this movement of the rotary table or the handling devices are explained in detail below with reference to Figures 4--7. A bushing 20 extending through a central bore 19 of rotary table 2 serves as a bearing therefor, which bushing is fastened at its lower end to a horizontal stationary frame 21 of the housing 1. The frame part 21 preferably forms therein the bottom of a laterally closed oil trough 22. An annular part 25 is rotatably mounted, by ball or roller bearings 23 and 24 on the outer surface of the bushing 20, on the upper side of which part 25 is fastened the rotary table 2. The central part of the annular part 25 has a laterally extending peripheral flange 26 to which is screwed a disc 27 which has on its outer periphery toothing, for example of Maltese cross form.

A roller 29 co-operates with the teeth 28, the roller being eccentrically arranged on a disc 30, which is fastened to the end of a rotatable shaft 31. With each rotation of the shaft 31 the roller 29 comes once into engagement with an indentation of the toothing 28 and accordingly rotates the disc 27 and therewith, by way of part 25, the rotary table 2 by a step determined by the division of the toothing 28.

In order to ensure an exact stepwise advance of the rotary table 2 and in particular to avoid an undesired movement of this table in between the two step movements, the disc 30 is preferably also formed as a cam disc to co-operate with a roller 32 of a lever 34, pivotally mounted at 33, in such a way, that an indexing pin 35 provided on the lever 34 falls into groove-shaped recesses arranged between the indentations or recesses 28' of the toothing 28 and locks the rotary table 2 against further rotation, as soon as the roller 29 is out of engagement with one of the indentations 28'. The lever 34 is biassed (Figure 6) by a tension spring 37 against the disc 27 or against the disc 30.

The shaft 31 is driven by a mitre gear 38, fastened to the underside of the frame part 21 and its drive shaft 39 is connected by a chain drive 40 with a shaft 41, which itself is then driven by an electric motor 43. The transmission ratio for the mitre gear 38 and with the chain drive 40 is so selected that the shaft 31 rotates twice as fast as the shaft 41, that is to say with the chain drive 40 and/or the mitre gear 38 a transmission ratio U of 2:1 is attained.

The shaft 41 carries at one end a cam disc 44 which effects the drive of the rod 17 and for this purpose has, at the periphery, two trough-shaped indentations 45 and 46 displaced through 180", the trough-shaped indentation 46 corresponding to the greater lifting movement of the rod 17 or the handling device 9 being formed deeper than the trough-shaped indentation 45.

The cam disc 44 acts on a roller 48 rotatably secured on a pivotal lever 47, that is to say the roller 48 abuts the peripheral surface of the cam disc 44, so that on each rotation of the shaft 41 and hence cam disc 44, the lever 47 is swung about a pivot 49 out of a raised position to a first lowered position, from this into the raised position again and following that into a second, deeper, lowered position and then swung back into the raised position. The roller 48 is fastened approximately to the centre of the pivotal lever 47, and at the free end of this pivotal lever there is a roller 50 which abuts against the hardened lower end of the rod 17, so that the rod 17 follows the movement of the pivotal lever 47 and also is twice lowered and again raised in each rotation of the shaft 41, whereby the two working strokes of the handling devices 9 are attained.

Obviously it would also be possible to allow the cam disc 44 to act directly on the lower end of the rod 17. In contrast, the use of an additional pivotal lever 47 has however the advantage that no lateral forces or forces acting transversely to the longitudinal axis of the rod 17 are transmitted to this rod. It is ensured through the selected transmission ratio U = 2:1 that with each working stroke or after each working stroke of the rod 17 the rotary table 2 is moved through one step.

As further shown in Figure 4 the plate 18 is fastened to the upper end of the stationary bushing 20, so that this plate 18, which has a central bore for the rod 17, is also stationary and can serve for holding the guide pillars 15 and 16 as well as other devices not described in detail.

A handling device 9 is illustrated in detail in Figure 7. In order to be able to position the first, and second, operative positions of each handling device independently of the other handling devices, the carrier beam 14 does not bear directly against the plate-shaped extension 17' of the rod 17, but there is provided on the relevant end of the carrier beam an adjustable contact surface in the shape of an adjustment screw 51 guided in a thread of the carrier beam, which screw consists, at least on its lower end, of hardened material and co-operates with a hardened surface of the plate-shaped extension 17'.

The second working position associated with the reception surface 4 is determined by this screw 51. A similar adjustment screw 52, is provided between the pillars 15 and 16, which in the lowering of the carrier beams 14 lies against a hardened contact surface 53 on the plate 18. By means of the adjustment screw 52 the first working position of the handling devices 9 associated with the pickup position of the conveyor devices 8, 11 and 12 is exactly adjusted. Furthermore a tension spring 54 is provided, which connects the carrier beam 14 with the plate 18 and biasses the carrier beam 14 downwardly.

In the embodiment shown the gripper tong halves 13' and 13" are actuated by means of a hydraulic cylinder 55 or by an associated piston 56 fastened in this cylinder, the free end of which acts on attachments 57 of the gripper tong halves 13' and 13", so that on actuation of the piston-cylinder arrangement (55, 56) the gripper tong halves 13', 13" are pivoted about the pivots 58 and 59 against the action of the tension spring 60 connecting the two gripper tong halves, whereby the tongs are opened.

One embodiment df the invention has been explained in the foregoing. It is clear that alterations and modifications thereto are possible without departing from the inventive concept.

Because of the simplified movement and control of the handling device, apparatus embodying the invention has an uncomplicated structure, works reliably and can be produced relatively economically, as compared with the known apparatus.

WHAT I CLAIM IS:- 1. Apparatus comprising a rotary table movable stepwise about a veritical axis and having a plurality of receiving stations spaced about its periphery, at least one transfer mechanism for transporting workpieces to or from the apparatus, and a handling device operable for transferring a workpiece from a transfer mechanism terminal to a rotary table receiving station or for transferring a workpiece form a rotary table receiving station to the transfer mechanism terminal, characterised in that the rotary table has recesses interposed between said receiving stations, the transfer mechanism terminal is disposed below the path of movement of the rotary table receiving stations and the handling device is movable only along a vertical axis intersecting the transfer mechanism terminal and the path of

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. The shaft 31 is driven by a mitre gear 38, fastened to the underside of the frame part 21 and its drive shaft 39 is connected by a chain drive 40 with a shaft 41, which itself is then driven by an electric motor 43. The transmission ratio for the mitre gear 38 and with the chain drive 40 is so selected that the shaft 31 rotates twice as fast as the shaft 41, that is to say with the chain drive 40 and/or the mitre gear 38 a transmission ratio U of 2:1 is attained. The shaft 41 carries at one end a cam disc 44 which effects the drive of the rod 17 and for this purpose has, at the periphery, two trough-shaped indentations 45 and 46 displaced through 180", the trough-shaped indentation 46 corresponding to the greater lifting movement of the rod 17 or the handling device 9 being formed deeper than the trough-shaped indentation 45. The cam disc 44 acts on a roller 48 rotatably secured on a pivotal lever 47, that is to say the roller 48 abuts the peripheral surface of the cam disc 44, so that on each rotation of the shaft 41 and hence cam disc 44, the lever 47 is swung about a pivot 49 out of a raised position to a first lowered position, from this into the raised position again and following that into a second, deeper, lowered position and then swung back into the raised position. The roller 48 is fastened approximately to the centre of the pivotal lever 47, and at the free end of this pivotal lever there is a roller 50 which abuts against the hardened lower end of the rod 17, so that the rod 17 follows the movement of the pivotal lever 47 and also is twice lowered and again raised in each rotation of the shaft 41, whereby the two working strokes of the handling devices 9 are attained. Obviously it would also be possible to allow the cam disc 44 to act directly on the lower end of the rod 17. In contrast, the use of an additional pivotal lever 47 has however the advantage that no lateral forces or forces acting transversely to the longitudinal axis of the rod 17 are transmitted to this rod. It is ensured through the selected transmission ratio U = 2:1 that with each working stroke or after each working stroke of the rod 17 the rotary table 2 is moved through one step. As further shown in Figure 4 the plate 18 is fastened to the upper end of the stationary bushing 20, so that this plate 18, which has a central bore for the rod 17, is also stationary and can serve for holding the guide pillars 15 and 16 as well as other devices not described in detail. A handling device 9 is illustrated in detail in Figure 7. In order to be able to position the first, and second, operative positions of each handling device independently of the other handling devices, the carrier beam 14 does not bear directly against the plate-shaped extension 17' of the rod 17, but there is provided on the relevant end of the carrier beam an adjustable contact surface in the shape of an adjustment screw 51 guided in a thread of the carrier beam, which screw consists, at least on its lower end, of hardened material and co-operates with a hardened surface of the plate-shaped extension 17'. The second working position associated with the reception surface 4 is determined by this screw 51. A similar adjustment screw 52, is provided between the pillars 15 and 16, which in the lowering of the carrier beams 14 lies against a hardened contact surface 53 on the plate 18. By means of the adjustment screw 52 the first working position of the handling devices 9 associated with the pickup position of the conveyor devices 8, 11 and 12 is exactly adjusted. Furthermore a tension spring 54 is provided, which connects the carrier beam 14 with the plate 18 and biasses the carrier beam 14 downwardly. In the embodiment shown the gripper tong halves 13' and 13" are actuated by means of a hydraulic cylinder 55 or by an associated piston 56 fastened in this cylinder, the free end of which acts on attachments 57 of the gripper tong halves 13' and 13", so that on actuation of the piston-cylinder arrangement (55, 56) the gripper tong halves 13', 13" are pivoted about the pivots 58 and 59 against the action of the tension spring 60 connecting the two gripper tong halves, whereby the tongs are opened. One embodiment df the invention has been explained in the foregoing. It is clear that alterations and modifications thereto are possible without departing from the inventive concept. Because of the simplified movement and control of the handling device, apparatus embodying the invention has an uncomplicated structure, works reliably and can be produced relatively economically, as compared with the known apparatus. WHAT I CLAIM IS:-

1. Apparatus comprising a rotary table movable stepwise about a veritical axis and having a plurality of receiving stations spaced about its periphery, at least one transfer mechanism for transporting workpieces to or from the apparatus, and a handling device operable for transferring a workpiece from a transfer mechanism terminal to a rotary table receiving station or for transferring a workpiece form a rotary table receiving station to the transfer mechanism terminal, characterised in that the rotary table has recesses interposed between said receiving stations, the transfer mechanism terminal is disposed below the path of movement of the rotary table receiving stations and the handling device is movable only along a vertical axis intersecting the transfer mechanism terminal and the path of

movement of the rotary table receiving station, in transferring the workpiece therebetween.

2. Apparatus as claimed in claim 1, wherein the spacing between neighbouring receiving stations corresponds to two movement steps of the rotary table.

3. Apparatus as claimed in claim 2, wherein the rotary table and the handling device are operable such that for transferring a workpiece from the transfer mechanism terminal to a rotary table receiving station the handling device is moved firstly from a first position above the rotary table through a recess between two neighbouring rotary table receiving stations to pick-up the workpiece from the transfer mechanism terminal below the path of movement of said receiving stations, then returns to a position above the path of movement of said receiving station from whence the device is again moved towards the rotary table for depositing the workpiece on a rotary table receiving station, the rotary table performing one movement step between the return and deposition movements of the handling device.

4. Apparatus as claimed in claim 2 wherein the rotary table and the handling device are operable such that for transferring a workpiece from a rotary table receiving station to the transfer mechanism terminal the handling device moves firstly from a position above the rotary table to pick up a workpiece from a rotary table receiving station returns to a position above the rotary table, and then moves through a rotary table recess to the subjacent transfer mechanism terminal for depositing the workpiece on said terminal, the rotary table performing one movement step, between the return and deposition movements of the handling device.

5. Apparatus as claimed in any preceding claim, wherein one or more receiving stations comprise a part fastened to the rotary table and projecting beyond the periphery thereof.

6. Apparatus as claimed in any preceding claim, wherein means for providing stepwise movement of the rotary table includes a Maltese cross transmission.

7. Apparatus as claimed in any preceding claim, including a detent mechanism for inhibiting movement of the rotary table in between two movement steps.

8. Apparatus as claimed in claim 7, wherein the detent mechanism comprises a pin engageable in a recess or groove of the rotary table or a part secured relative thereto, the pin being disengageable by cam means operable for stepwise movement of the rotary table.

9. Apparatus as claimed in any preceding claim comprising a plurality of handling devices, all operable by a common push-rod.

10. Apparatus as claimed in any preceding claim, wherein each handling device comprises a carrier beam having at one end gripping tongs and being supported by guide elements on a stationary part of the apparatus.

11. Apparatus as claimed in claim 10, wherein the stationary part comprises a plate arranged concentrically with the rotary table.

12. Apparatus according to claim 10 or 11 as appendant to claim 9, wherein the carrier beam abuts against said push-rod at a position remote from the gripping tongs.

13. Apparatus as claimed in any of the claims 9 to 12, wherein one end of said pushrod cooperates with a cam.

14. Apparatus as claimed in claim 13, wherein the cam is a cam disc acting on a pivotal lever, the free end of which lever abuts against the push-rod.

15. Apparatus as claimed in any preceding claim, further comprising first driving means for providing the stepwise movement of the rotary table and second driving means for moving the handling device, with each of said driving means having a shaft driven by a common motor, and further comprising at least one transmission gear interposed between said common motor and one of said driving means shafts, the transmission ratio of said gear being such that the shaft of the first driving means is driven twice as fast as the shaft of the second driving means.

16. Apparatus arranged and adapted to operate substantially as herein described with reference to and as shown in the accompanying drawings.