AU682771B2 - Turning device and cam guide mechanism included therein - Google Patents

Description

WO 95/30612 PCT/SE95/00482 1 TURNING DEVICE AND CAM GUIDE MECHANISM INCLUDED THEREIN Field of the Invention This invention relates to a device for turning an object, and more specifically concerns a turning device as set forth in the preamble to appended claim i. The invention further relates to a cam guide mechanism intended for use in the turning device.

Background of the Invention Various conveyors, packaging machines and the like are used for conveying and handling objects, and frequently require that the objects can be turned through a predetermined angle. The reason for this may be that the object is to be oriented in another direction and subsequently be further conveyed by the same conveyor, or that the object is to be transferred to another conveyor and thus has to be turned through a predetermined angle, for instance an angle of 900.

In both cases, the object at issue is frequently conveyed by some sort of conveyor, for instance a belt conveyor, up to a turning site or junction, where the object is momentarily stopped and first is lifted a certain distance in tbe vertical direction by one and the same turning device so as to be released from the conveyor and be supported by the turning device. The object is then turned through the predetermined angle and is finally lowered so as to rest on the conveyor in the turned position. Thus, the turning operation often involves a lifting operation.

US-3.100,039 teaches a conventional method of achieving the combined lifting and turning operation described above. The US document describes a turning device intended for use in association with a conveyor.

This turning device comprises a turntable which, with the aid of a first pneumatic piston and cylinder unit, is movable in the vertical direction along an axis between a I- WO 95/30612 PCl/SE95/00482 2 lower position on a level with an adjoining conveyor belt and an upper position above the conveyor belt. Furthermore, the turntable is, with the aid of a second pneumatic piston and cylinder unit, reciprocatingly turnable about the axis within a restricted angular range.

However, this prior-art construction suffers from a number of drawbacks. Thus, the linear lifting and lowering movement of the turntable, as well as the turning movement thereof, is brought about with the aid of various driving means. This constitutes a complicated solution, since the relative movements of the driving means thus have to be svnchronised. In addition, the turning movements of the turntable are reciprocating, the forward movement actively causing an object to turn, whereas the backward movement merely returns the turntable to a suitable position in view of a subsequent forward movement for turning the object. As a result, only every other turning movement of the turntable is an active movement, i.e. causes the supported object to turn. Also, this conventional construction is disadvantageous in that the mechanical components involved in the turning operation are subjected to a considerable load when heavy objects are to be lifted and turned.

There is thus a demand for a better solution than the one offered by the prior-art construction described above.

One object of the invention is to provide a device which is adapted to turn an object while the tte undergoes a linear reciprocating movement, _\in the vertical direction, and which obviatea the drawbacks mentioned above.

Another object of the invention is to provide a turning device which is subjected to less torsional stress than prior-art devices.

Summary of the Invention According to one aspect the present invention provides a device for turning an object through a predetermined angle about an axis, comprising a frame, a supporting means which is adapted to support said object and which, in relation to the frame, is reciprocatingly movable along and turnable about said axis, and a driving means which is connected to the supporting means in order to produce the reciprocating movement thereof, and a cam guide mechanism which is arranged between and connected to the frame and the supporting means and which is so designed that a linear force generated by the driving means in order to produce the reciprocating movement of the supporting means is partly converted to a turning force acting on the supporting means, such that the latter is turned through said predetermined angle during a cycle of reciprocating movement.

In a preferred embodiment of the invention the cam guide mechanism comprises an undulated guiding groove running endlessly about the axis at a radial distance therefrom, and at least one cam follower accommodated in and 20 travelling along the guiding groove, one of said guiding groove and said at least 20 one cam follower being connected to said frame, while the other of said guiding o groove and said at least one cam follower is connected to the supporting means.

Preferably, during a cycle of reciprocating movement of the supporting means, the cam follower first travels along an upper cam surface of the undulated guiding groove from a starting position in a trough to a turning position on a crest, and then travels along a lower cam surface of the undulated guiding groove to an end position in a trough, an upper end of the lower cam surface being so offset in the circumferential direction in relation to the turning position that the cam follower encounters tha lower cam surface when a linear return movement is begun, and said end position constituting a new starting position for a subsequent cycle of movement.

According to another aspect this invention provides a cam guide \R--mechanism, wherein it comprises a first member and a second member which are 2B rotatable in relation to each other about an axis, as well as reciprocatingly moveable in relation to each other along the same axis, the first member comprising an undulated guiding groove running endlessly round said axis at a radial distance therefrom, and the second member comprising at least one cam follower which is accommodated in and travels along the guiding groove, and wherein the cam guide mechanism is so designed that, during a reciprocating, linear relative movement of the first and the second member, the cam follower first travels along a front cam surface of the undulated guiding groove from a starting position in a trough to a turning position on a crest, and then travels along a rear cam surface of the undulated guiding groove to an end position in a trough, a front end of the rear cam surface being so offset in the circumferential direction in relation to the turning position that the cam follower encounters the rear cam surface when a linear return movement is begun, and said end position constituting a new starting position for the subsequent cycle of movement.

S a S S 55.

a I **o a lb h« WO 95/30612 PCT/SE95/00482 3 Summary of the Invention According to the invention, these and other e ects are attained by a turning device having th3 istinctive features recited in appended claim 1 referred embodiments of the turning device be'n. defined in dependent claims 2-10.

The invention rthe- provides a cam guide mechanism having the iinctive features recited in independent claim preferred embodiments of the cam guide mecha- /ism being defined in dependent claims 12-14.

The present invention has several advantages over the prior art. The fact that a single driving means, which may be of simple and conventional design, achieves not only the lifting and lowering movement but also the turning movement results in a construction which, generally speaking, is less expensive than prior-art turning devices. In addition, the use of a single driving means of simple design increases the service life of the turning device, since there are but a few mechanical components running the risk of being exposed to wear. Furthermore, there is no need of synchronising several separate driving means during the turning cycle.

The inventive construction, in which the turning movement is achieved by converting a component of a linear force to a torsional force, further entails that the mechanical components involved in the turning operation are not exposed to torsional stress of any significance. This means that the device is able to take up a greater load and that the component parts are not much worn.

The invention further enables the prior-art, inactive, backward turning movement to be dispensed with, since the turning movement according to the invention can be achieved continuously in the same direction.

It should further be emphasised that the linear movement of the turning device and the cam guide mechanism according to the invention may be vertical, as will L1 d II 3A be described below in connection with the preferred embodiment nf the invention, as well as non-vertical, for instance horizontal. Thus, the appended claims are meant to encompass all conceivable directions of the axis of movement of the device, and all references in the foregoing as well as in the following to a lifting and lowering movement, as well as to a movement in the vertical direction, are to be interpreted accordingly.

In addition, throughout the description and claims of this specification the word "comprise" and variations of the word, such as "comprising" and "comprises", are not intended to exclude other additives or components or integers.

a a i i go 4

C

a -I WO 95/30612 PCT/SE95/00482 4 be described below in connection with the preferred em diment of the invention, as well as non-vertica lfor instance horizontal. Thus, the appended cliams are meant to encompass all conceivable dir etons of the axis of movement of the device, alli references in the foregoing as well as he following to a lifting and lowering movem e as well as to a movement in the vertical di cecion, are t, be interpreted accordingly.

Brief Description of the Drawings A preferred embodiment of the inventive turning device in the form of a turntable, as well as an inventive cam guide mechanism included therein, will now be described in more detail with reference to the accompanying drawings, in which Fig. 1 is a side view of the turntable, which is disposed in a roller conveyor and shown when occupying a lower initial position, Fig. 2 is a top view of the turntable and the conveyor in Fig. 1, Fig. 3 is a side view of a frame forming part of the turntable, Fig. 4 is a top plan view of a jacket for the frame in Fig. 3 when in flat state, Fig. 5 is a section taken along the line A-A in Fig. 3, Fig. 6 is a side view of a lifting piston forming part of the turntable, Fig. 7 is a section taken along the line B-B in Fig. 6, and Fig. 8 is a side view of a cam follower adapted to be mounted in the lifting piston shown in Fig. 6.

Description of a Preferred Embodiment In Figs 1 and 2, the turntable is disposed in a horizontal roller conveyor with rollers 100 mounted in a stand 110, the turntable being here adapted to turn some -r b~LP~L~- ~I WO 95/30612 PCTISE95/00482 sort of object, for instance a carton (not shown), about a vertical axis 1 through an angle of 900 in the direction indicated by the arrow a.

As appears from Fig. i, the turntable comprises a driving means in the form of a vertical piston and cylinder unit 2 including a cylinder 3 and a piston rod 4 which is reciprocatingly movable along the axis 1, as well as freely turnable about the latter. The turntable further comprises a supporting means 5, which is intended to support the object and includes an elongate lifting piston 6, which is centred round and extends vertically along the axis 1 and which, at its lower end, is rigidly connected to the piston rod 4 by means of a screw joint 8. The supporting means 5 is thus vertically adjustable along the axis 1, as well as turnable about the latter.

It appears from Figs 6-8 that the lifting piston 6 at its lower end has four recesses 7, which are directed radially inwards and each are adapted to accommodate a cam follower 11 in the form of a roller bearing which, with its inner ring, is fastened by screws in the respective recesses 7.

The supporting means 5 further comprises two orthogonal supporting plates 12, 13 which, by the intermediary of a spacer 10, are connected to the upper end of the lifting piston 6 and which together form the shape of a cross perpendicular to the axis 1.

As appears from Fig. i, the supporting plates 12, 13 are, in the initial position of the turntable, located on a level beneath the upper periphery of the rollers 100.

It is further evident from Figs 1 and 3-5 that the turntable comprises a frame 16, which is stationary in relation to the stand 110 of the conveyor and which includes an elongate, cylindrical jacket 18, which is centred round and extends vertically along the axis 1 so as to surround essentially the entire lifting piston 6.

The inside diameter of the jacket 18 corresponds to the diameter of the lifting piston 6. The jacket 18 is clamp- L~er WO 95/30612 PCTISE95/00482 6 ed in, and supported by, a supporting element 20 of the frame 16, this element being arranged above the piston and cylinder unit 2 and having an opening for receiving the latter. The jacket 18 is made up t.f two substantially identical parts, namely an upper part 22 and a lower part 24, which are rigidly interconlected with the aid of four vertical connecting rods 26.

The jacket parts 22, 24 are shown in flat state in Fig. 4, from which it appears that the Jacket-part ends facing one another are provided with recesses in such a manner that there is formed, between the two jacket parts 22, 24, an undulated, throughgoing guiding groove 28 running endlessly in the circumferential direction and being adapted to accommodate the cam followers 11. The guiding groove 28 has a width corresponding to, but being slightly larger than, the diameter of the cam followers 11.

The guiding groove 28 comprises vertical lower portions 30, forming the troughs of the guiding groove, and vertical upper portions 32, forming the crests of the guiding groove. A vertical axis 34 extends through each vertical portion 30, 32 and is horizontally centred therein.

Furthermore, the guiding groove 28 comprises upwardly inclined portions 36, each having an upper cam surface 38, as well as downwardly inclined portions 40, each having a lower cam surface 42. Each upper cam surface 38 extends from a downwardly-directed narrow end 44, which consists of the transition between one of the downwardly inclined portions 40 and one of the upwardly inclined portions 36, to the point where the guiding groove 28 passes from the upwardly inclined portion 36 to an upper vertical portion 32. Each lower cam surface 42 extends from an upwardly-directed narrow end 46, which consists of the transition between one of the upwardly inclined portions 36 and one of the downwardly inclined portions to the point where the guiding groove 28 passes from WO 95/30612 PCTSE95100482 7 the downwardly inclined portion 40 to a lower vertical portion Each downwardly-directed narrow end 44 and each upwardly-directed narrow end 46 are offset in the lateral direction (to the left in Fig. 4) in relation to respective axes 34, i.e. in relation to the centre of respectively the lower and the upper vertical portions 32 of the guiding groove 28.

The turntable operates as follows. In a lower initial position, the piston rod 4 of the piston and cylinder unit 2 occupies a retracted position, in which the supporting plates 12, 13 are located on a lower level than the upper periphery of the rollers 100, and in which each cam follower 11 occupies a starting position P1 (shown in Fig. 4) and rests on the bottom of one of the lower vertical portions 30 of the groove 28, the cam follower 11 thus taking up the dead weight of the supporting means Initially, the object to be turned is conveyed to a position above the supporting plates 12, 13 by means of the conveyor. The piston and cylinder unit 2 is then actuated, causing the piston rod 4 to perform a linear lifting movement along the axis i. As a result of the upward linear movement of the piston rod 4, the lifting piston 6 is likewise moved upwards, each cam follower 11 received in the guiding groove 28 being, owing to this linear movement, caused to follow the lower vertical portion 30 of the groove 28 up to a lower intermediate position P2. Having reached this lower intermediate position P2, the cam follower 11 encounters the upper cam surface 38 and is thus forcibly applied against the latter as the lifting movement continues. The linear force generated by the piston and cylinder unit 2 is, as a result, partly converted to a torsional force, such that the piston rod 4 and the supporting means 5 will, in addition to the lifting movement, be subjected to a turning movement. The cam follower 11 travels in contact with the upper cam WO 95/30612 PCTISE95/00482 8 surface 38 along the entire length thereof, up to an upper turning position P3, where the cam follower 11 is located in the upper vertical poriLon 32 of the guiding groove 28. In the turning position P3, the piston rod 4 and the supporting means 5 have, as seen in Fig. 2, been turned anticlockwise through a part angle of 450 in relation to the starting position- When the cam follower has reached the turning position P3, the supporting means 5 i thus completely uplifted. As a result of a subsequent linear lowering movement of the piston rcd 4, the cam follower 11 is moved vertically downwards from the turning position P3 to an upper intermediate position P4, where the cam follower 11 instead encounters the lower cam surface 42. As the lowering movement continues, the cam follower 11 travels in contact with the lower cam surface 42 along the entire length thereof to a lower intermediate position P5, the suppoxting means 5 and the piston rod 4 being thus com- 1 pelled to turn anticlockwise, as seen in Fig. 2, through a second part angle of 45°. Finally, the supporting means is lowered in the vertical direction without turning, such that the cam follower 11 reaches an end position P6, which corresponds to the starting position P1, the only difference being that the end position P6 is located in a successive trough of the guiding groove 28, as compared with the trough where the starting position P1 is located. The supporting plates 12, 13 will thus again be located on a level beneath the upper periphery of the rollers 100, thus releasing the object from the supporting plates. The piston and cylinder .unit 2 has thus completed a cycle consisting of a lifting and a lowering movement, while the supporting means 5 simultaneously has been turned through 90°. It will be appreciated that the end position P6 constitutes the starting position P1 of the subsequent cycle of movement.

Owing to the special design of the groove with lower and upper narrow ends 44, 46 offset in the lateral direc- I WO 95/30612 PCT/SE95/00482 9 tion in relation to the axis 34, the cam follower 11 will be brought into direct application against the respective upper and lower cam surfaces 38, 42.

Thus, the object to be turned is first located on the supporting rollers 100 above the turntable at a distance therefrom. When the driving means 2 is actuated, the object is first lifted a small distance, such that the supporting plates 12, 13 come -to occupy a level above the upper periphery of the rollers 100 in order not to be interfered with during the subsequent turning movement.

As the lifting movement continues, the object is gradually turned through 450 in a predetermined direction. Then, the driving means 2 is actuated in the opposite direction, such that the object is lowered and thus simultaneously is turned through another 450 in the same direction. Finally, the turntable is lowered beneath the supporting rollers 100, and the object thus turned through 900 again rests on the supporting rollers to be further conveyed thereby.

It will be appreciated that all the cam followers 11 simultaneously perform a corresponding movement in their respective parts of the endless undulated guiding grcove 28. It is also to be understood that the supporting means will be turned through another 900 in the same direction during the subsequent cycle of movement of the piston and cylinder unit 2.

Conceivable Modifications of the Invention It goes without saying that the invention is by no means restricted to the preferred embodiment described above, but can be modified in many ways within the scope of the appended claims. For instance, the vertical portions 30 and/or the vertical portions 32 may be dispensed with. Also, the inclined portions need not be straight but may, for example, have the shape of half a parabola.

In addition, the jacket part, 22, 24 may be mutually turnable about the axis 1, thus enabling turning in both 1 WO 95/30612 PCT/SE95/00482 directions. There may be provided one cam follower 11 only. Moreover, the guiding groove 28 and the cam followers 11 may change places, i.e. the guiding groove 28 may be provided in the lifting piston 6, while the cam followers 11 are stationarily supported by the frame 16.

Finally, it should once more be emphasised that the use of the turning device need not be focused on the vertical direction, for which reason the expressions "up" and "down" as well as "upper" and "lower" throughout are to be interpreted in the broad sense, as referring to opposite directions in relation to the orientation of the main axis.

Claims (15)

1. A device for turning an object through a predetermined angle about an axis, comprising a frame, a supporting means which is adapted to support said object and which, in relation to the frame, is reciprocatingly movable along and turnable about said axis, and a driving means which is connected to the supporting means in order to produce the reciprocating movement thereof, and a cam guide mechanism which is arranged between and connected to the frame and the supporting means and which is so designed that a linear force generated by the driving means in order to produce the reciprocating movement of the supporting means is partly converted to a turning force acting on the supporting means, such that the latter is turned through said predetermined angle during a cycle of reciprocating movement.

2. A device as set forth in claim 1, wherein the cam guide mechanism comprises an undulated guiding groove running endlessly about the axis at a radial distance therefrom, and at least one cam follower accommodated in and o. travelling along the guiding groove, one of said guiding groove and said at least one cam follower being connected to said frame, while the other of said guiding groove and said at least one cam follower is connected to the supporting means.

S3. A device as set forth in claim 2, wherein, during a cycle of recipiocating movement of the supporting means, the cam follower first travels see along an upper cam surface of the undulated guiding groove from a starting 25 position in a trough to a turning position on a crest, and then travels along a lower cam surface of the undulated guiding groove to an end position in a trough, an upper end of the lower cam surface being so offset in the circumferential direction in relation to the turning position that the cam follower encounters the lower cam surface when a linear return movement is begun, and said end position constituting a new starting position for a subsequent cycle of movement.

4. A device as set forth in claim 3, wherein the cam guide mechanism t is so designed that the supporting means is turned through a first part angle in a C:AVVINWORDUENNIFERARIOSNODEFTELE2587P2I I II 12 predetermined turning direction when the cam follower is moving from the starting posit;jn to the turning position, and through a second part angle in the same turning direction when the cam follower is moving from the turning position to the end position, said part angles together forming said predetermined angle.

5. A device as set forth in any one of claims wherein the endless, undulated guiding groove comprises at least two troughs and at least two crests.

6. A device as set forth in claim 5, wherein the distance between two successive troughs is the same along the entire circumference of the guiding groove.

7. A device as set forth in any one of claims 2-6, wherein the guiding groove is provided in the frame, and the cam follower is connected to the supporting means in order to move jointly therewith.

8. A device as set forth in any one of the preceding claims, wherein the driving means consists of a piston and cylinder unit extending along said axis and comprising a stationary element which, at its upper end, is rigidly connected to the frame, and the supporting means comprises an elongate lifting piston which is centred S round and extends along said axis, a lower end of the lifting piston being rigidly S connected to an upper piston end of the pic aid cylinder unit, and an upper end of the lifting piston being rigidly connected to a supporting element of the supporting means extending transversely of said axis.

9. A device as set forth in any one of the preceding claims, wherein the cam follower is in the form of a roller bearing, which is supported by the lifting piston and projects radially therefrom. 25

10. A device as set forth in any one of the preceding claims, wherein the frame has a cylindrical jacket.

:11. A cam guide mechanism, wherein it comprises a first member and a second member which are rotatable in relation to each other about an axis, as well as reciprocatingly moveable in relation to each other along the same axis, the first member comprising an undulated guiding groove running endlessly round said axis at a radial distance therefrom, and the second member comprising at S least one cam follower which is accommodated in and travels along the gucLtng I iI I 13 groove, and wherein the cam guide mechanism is so designed that, during a reciprocating, linear relative movement of the first and the second member, the cam follower first travels along a front cam surface of the undulated guiding groove from a starting position in a trough to a turning position on a crest, and then travels along a rear cam surface of the undulated guiding groove to an end position in a trough, a front end of the rear cam surface being so offset in the circumferential direction in relation to the turning position that the cam follower encounters the rear cam surface when a linear return movement is begun, and said end position constituting a new starting position for the subsequent cycle of movement.

12. A cam guide mechanism as set forth in claim 11, wherein it is so designed that the first member and the second member are turned in relation to each other through a first part angle in a predetermined turning direction when the cam follower is moving from the starting position to the turning position, and through a second part angle in the same turning direction when the cam follower is moving from the turning position to the end position, said part angles together forming a predetermined angle.

13. A cam guide mechanism as set forth in claim 11 or 12, wherein the endless, undulated guiding groove comprises at least two troughs and at least two crests.

14. A cam guide mechanism as set forth in claim 13, wherein the distance between two successive troughs is the same along the entire circumference of the guiding groove.

15. A device for turning an object through a predetermined angle about S 25 an axis substantially as herein described with reference to the accompanying drawings. A cam guide mechanism substantially as herein described with i reference to the accompanying drawings. DATED: 18 July, 1997 PHILLIPS ORMONDE FITZPATRICK Attorneys for: RYDEN I-