COUPLING DEVICE AND PLASTICS PROCESSING MACHINE WITH A COUPLING DEVICE

Description

[0001] The present invention relates to a coupling device for a conveyor screw and a drive driving the same of a plastics processing machine according to claim 1 and to a plastics processing machine with a coupling device for a conveyor screw and a drive driving the same according to claim 12.

[0002] Conventional coupling devices are often complex structures that are usually located in areas that are difficult to access and barely visible, making user-friendly handling difficult.

[0003] An example of such a complex solution can be found, for example, in DE 37 35 701 C1. This describes a plastic injection molding unit with a locking device for the simultaneous, program-controlled locking of the plasticizing cylinder and the conveyor screw to the support block of the plasticizing cylinder or to the rotatable drive shaft for the conveyor screw. This locking device can be inserted into a corresponding drive profile of a driver piece of the drive shaft by means of a driver profile and can be axially displaced by means of hydraulic injection cylinders to inject the plastic. Furthermore, it has two slides that are radially guided on the block and arranged diametrically opposite each other and can be displaced from their locking position by means of at least one hydraulic cylinder.It also features a rotatable slider guided radially on the driver piece, which can be moved out of the locking position by means of the same hydraulic cylinder into a desired angular position that enables locking of the screw conveyor. The desired angular position can be achieved using an orientation device that controls the rotary motor for the screw conveyor to a standstill. A driver bridge is attached to one of the diametrical sliders, which engages behind the rotatable slider at the desired angular position, ensuring a joint locking movement of the diametrical and rotatable sliders.

[0004] The solution presented in EP 0 595 200 B1 is also an example of this. It describes a coupling device on a plastic injection molding machine for coupling a conveyor screw, which is rotatable and axially displaceable in the removable plasticizing cylinder during the injection cycle, to a spindle of a machine-side drive device that is coaxial with an axis. The coupling device has at least one axial locking device that is subject to rotational movement. The locking elements belonging to the machine-side coupling are accommodated in a receptacle facing the conveyor screw, which is detachably connected to the drive device via threaded bolts. The receptacle is connected via threaded bolts to bores in the spindle, which are arranged at an angle to a plane passing through the axis.

[0005] The conveyor screw is fastened to the drive bushing using a tightened hexagon union nut, for example, so that both rotational movements and axial displacements can be transmitted through the drive. The drive shaft is usually blocked by a freewheel in the tightening direction of the union nut, which prevents it from rotating during tightening. To loosen the union nut to remove the screw, the drive shaft must be secured against twisting, as it would otherwise rotate due to the loosening torque. This often requires a sufficiently dimensioned access opening for aids or tools, especially special tools, while at the same time ensuring visual insight so that the operations can be monitored visually. There is often no way to check whether the conveyor screw is correctly seated in the drive bushing and has been fully accommodated.For example, due to contamination, burrs, defects, geometric deviations, etc., there is a risk that the screw has not been installed in the correct position and this remains undetected by the operator. This can result in malfunctions during operation, such as the nut coming loose, insufficient torque transmission, or the screw conveyor exhibiting excessive axial play. Component failure is also possible.

[0006] DE 38 08 769 A1 describes a device for changing the plasticizing unit of an injection molding machine with a plasticizing cylinder detachably attached to the machine and a coupling device consisting of at least two coupling parts for positive radial and axial locking between a conveyor screw mounted rotatably and axially displaceably in the plasticizing cylinder and a drive shaft connected to a rotary motor for the rotary movement and a piston-cylinder unit for the axial movement of the conveyor screw. One coupling part of the coupling device has grooves extending axially along its circumference, into which at least one locking body and a driver of the other coupling part can be inserted together. After insertion, the locking body(s) can be moved into a position in which they engage behind a locking surface of the coupling part for the purpose of axial locking.

[0007] DE 35 28 154 C1 discloses a solution comprising a coupling device on a plastic injection molding machine for coupling a coupling part, which is periodically moved during the injection cycle, of an automatically replaceable working unit that can be transported transversely to the injection axis, with its hydraulic drive device arranged in the injection axis when the working unit is in the installed position. The coupling device has slides arranged diametrically to the injection axis, which, for axial coupling, can be guided by means of springs into an annular groove of one coupling part and are guided radially displaceably in a sliding housing that is attached to the other coupling part. A radially displaceably guided expanding wedge can be driven slightly into a linear sliding joint between the slides by means of a radially arranged piston-cylinder unit as a radial cylinder to control the slides out of the annular groove.The coupling device with axial locking mechanism connects a rotating and axially displaceable conveyor screw as a working unit in the plasticizing cylinder to a radially and axially driving spindle of the drive device, and is assigned a positive-locking, axially disengageable radial coupling and an orientation device. The joint rotational movement of the slides of the axial locking mechanism and the radial coupling can be terminated approximately at a desired angular position of the slide joint, in which the desired angular position of the slide joint runs parallel to the working direction of the radial cylinder.

[0008] In addition, some systems require significant force / torque inputs to engage or disengage the screw conveyor, resulting in increased operating effort or, in extreme cases, damage to other machine elements not designed to withstand these loads. However, these high torques, e.g., in the case of a tight nut, are often not transferable due to the limited surrounding space and the associated restricted tool movement radius.

[0009] DE 10 2020 100 444 A1 describes a plasticizing unit for a molding machine with a coupling element for releasably connecting a plasticizing screw to a drive shaft. The plasticizing screw can be set into a rotational movement about a central axis of the plasticizing screw by means of at least one shaft-hub connection through the drive shaft. The plasticizing screw can be releasably secured or is releasably secured by the coupling element against axial movements substantially parallel to the central axis of the plasticizing screw. The coupling element has at least three locking elements that are radially displaceable for releasably axially securing the plasticizing screw.

[0010] DE 42 23 489 A1 describes a coupling device for an injection molding machine for releasably connecting an axially displaceable worm shaft to a drive shaft. The worm shaft has an insertion end provided with external toothing, which is offset from a shaft shank by a larger-diameter shoulder formed on an annular shoulder. The worm shaft can be inserted with the insertion end into a coupling sleeve of the drive shaft, which has a corresponding internal toothing. Two crescent-shaped, radially pivotable locking pawls are mounted on the end face of the coupling sleeve. These pawls engage behind the insertion end inserted into the coupling sleeve on the annular shoulder of the worm shaft and bear against the end face.

[0011] DE 32 29 223 A1 discloses a clutch device in which an output piston of a drive device is provided with a clutch housing in which a clutch piston is arranged, spring-loaded in the clutch engagement direction and pressurizable in the direction of clutch disengagement, and guided in the direction of clutch disengagement. The clutch piston is connected to a clamping cage via a tappet. Due to the spring loading of the clutch piston, the clamping cage, which is arranged radially between the clutch housing and a head portion of a worm shaft, is deformed in such a way that it frictionally connects the clutch housing and the worm shaft in such a way that both axial forces and torques can be transmitted from the drive device to the worm. By applying pressure to the clutch piston against the spring action, the clamping cage relaxes and the frictional connection is released, so that a plasticizing unit can be removed.The coupling device is particularly suitable for the fully automatic exchange of the plasticizing unit.

[0012] DE 15 29 788 A1 describes a gear unit with a hollow output shaft of a gearbox, to whose left end a worm shaft is releasably coupled with a groove and sliding key for axial movement for the purpose of driving. At the right end of the output shaft, a device for driving the screw of a plastics-processing extruder is arranged. Directly connected to one end of the hollow output shaft of the gearbox is a cylinder sleeve or a connecting element of a chuck-like device by means of a bayonet lock consisting of retaining pins and guide slots. A cover enclosing the chuck-like device is firmly connected to the connecting element by means of screws. A stepped periphery of the cover serves as a slideway for the chuck-like device, concentric with the output shaft.A retained edge of the cover, together with two projections of the connecting element with a circular cross-section, forms the axial guide on both sides for the rotating, chuck-like device. Furthermore, a notch is provided in the circumference of the cover, into which a locking pin, under the pressure of a leaf spring, engages when the threaded jaws are in the open position. These jaws can be easily and quickly closed around or released from a spindle by rotating the chuck-like device.

[0013] DE 20 35 788 A1 describes a quick coupling for cardan shafts, particularly on agricultural machinery, with a power take-off shaft stub on the tractor and a funnel-shaped, widened end piece of a cardan shaft that can be coupled thereto, with devices for transmitting torque when coupled. Spring-loaded locking members are arranged in an inner radial groove of an end piece of the cardan shaft and, with outwardly bent free ends, penetrate openings in the end piece. Compression springs for the locking members are inserted between an inner wall of the end piece and the semicircular locking members, and the latter are pressed into the interior of the end piece by spring force. A conical coupling part fastened to the power take-off shaft stub has an outer radial groove for the engagement of the locking members.

[0014] DE 84 00 654 U1 discloses a separable power take-off shaft coupling device comprising a coupling pin bearing external gearing and a coupling sleeve, into whose coaxial bore with internal gearing the coupling pin can be inserted, creating a rotationally fixed, positive connection. The coupling pin interacts in a positive manner with a radially movable, releasable locking device mounted in the coupling sleeve, which, when the coupling pin is inserted into the coupling sleeve, interacts with a locking member provided on the coupling pin. This secures the coupling pin against axial displacement in the coupling sleeve. The locking device is formed by at least one lever having a radially inward-facing hook at its end, which is pivotally mounted on an axis extending perpendicular to the longitudinal axis of the coupling sleeve and is seated in the coupling sleeve.The locking member is formed by an extension attached to the coupling pin, which, when coupled, is engaged by the hook and rests against a stop on the coupling sleeve.

[0015] JP S60157214 U describes the connection of a screw of an injection molding machine to a drive shaft. A portion of the rear end of the screw is attached to a drive shaft connecting device, and a number of connecting parts passing through the connecting device are engaged with an annular groove of the rear end of the screw by means of a connecting part actuating ring around the outside of the connecting element. Furthermore, in the connecting device that integrally connects the drive shaft and the screw, the connecting element consists of a connecting piece provided at the upper part of the element and a plate-shaped bridge element fixed to the lower end of the element.The actuating ring accommodates an equal number of cam grooves as the connecting element, and a fitting element is fitted into the cam groove to connect the connecting element to the actuating ring in such a way that it is movable in the radial direction. The connecting element and the worm are connected via the bridge element, which is positioned so that it can be freely removed.

[0016] Document JP S503572 Y1 discloses parts of an injection device in which an injection screw is rotated by a drive shaft, and a splined shaft at the rear end of a screw shaft is fitted into a splined hole in the drive shaft. To axially lock the screw to the drive shaft, a V-shaped retaining groove is provided in a portion of the screw shaft located forward of the splined shaft. This V-shaped retaining groove completely surrounds the screw shaft and engages a tip of a retaining pin, which is part of a retaining ring encompassed by a thrust ring, both of which are arranged on a front periphery of the drive shaft and surround the splined hole. The retaining pin cooperates with a first spring, both of which are arranged in an opening in the retaining ring, the retaining pin being moved radially outward by the first spring in an unloaded state.A limit pin is arranged on an outer circumference of the retaining ring, and a second spring is arranged in a recess in the outer circumference, which moves a ball radially outward. During assembly of the worm, first, before the spline shaft can be fitted into the spline hole, a semicircular recess provided on the inner surface of the thrust ring is rotated into an overlap position with the retaining pin by rotating the thrust ring in a first direction, whereby the retaining pin is moved radially outward by the first spring and the tip end of the retaining pin is retracted enough to allow the spline shaft to be inserted. In this state, when the spline shaft is pushed into the spline hole until it comes into contact with the end of the spline hole, the V-shaped retaining groove provided in the worm shaft comes into an overlap position with the retaining pin.If the thrust ring is then turned in the opposite direction until the limit pin hits an end part of an engagement groove in the thrust ring, where the positioning ball is pushed into a groove in the thrust ring by the second spring and locked therein, the retaining pin is pushed forward by the thrust ring into the V-shaped retaining groove in the worm shaft, so that the worm is axially locked in this position. The splined shaft is removed from the splined hole by turning the thrust ring again in the first direction, whereby the retaining pin is moved radially outwards out of the V-shaped retaining groove. To increase the locking security, three retaining pins are provided in corresponding openings in the retaining ring, evenly distributed around the circumference of the worm shaft.

[0017] What all of the coupling devices mentioned above have in common is that they require a tool to release the connection, which can be used to move the coupling device from a locked to a unlocked state. In practice, this very often leads to damage to the injection devices due to the limited space available for the tool.

[0018] The invention is therefore based on the object of providing a coupling device which can be operated intuitively without tools even under unfavourable environmental conditions and which can be easily locked and unlocked, has no negative effects with regard to the rotation of drive shafts and avoids damage to other elements.

[0019] This is achieved with a method according to the features of claim 1. The method is based on a coupling device for a conveyor screw and a drive driving the same of a machine for processing plastics and other plasticizable materials, for the positive coupling of a conveyor screw shaft to a drive shaft. In the coupled state, in order to lock the conveyor screw shaft to the drive shaft, at least a part of at least one movable, spring-loaded holding element of the coupling device can be guided radially into at least one recess in the conveyor screw shaft and / or against at least one elevation of the conveyor screw shaft in the direction of an axial axis extending through the conveyor screw shaft, the coupling device, and the drive shaft. A ring, which can be operated manually without tools and is arranged around a body of the coupling device and around the axis, can be rotated along a circumference of the ring.This is also achieved with a plastics processing machine with a corresponding coupling device for a conveyor screw and a drive driving the screw according to claim 12.

[0020] Advantageously, such a coupling device can be easily operated, even manually. The ring allows the release or locking forces to be effectively transmitted across the entire circumference of the coupling device, while simultaneously creating the structural prerequisites for operation at virtually any angular position. There is no need to control a specific angular position. Since access is possible at virtually any point, accessibility during operation is also facilitated.

[0021] Advantageous further developments are the subject of the dependent patent claims.

[0022] In a first preferred embodiment of the coupling device which improves the installation possibility of the coupling device, the at least one part of the at least one holding element is held by at least one spring in an unlocked, actuated state away from the axis or in a locked, actuated state towards at least one recess and / or elevation.

[0023] In a further preferred embodiment of the coupling device that improves the installation option of the coupling device, at least one part of the at least one retaining element is advantageously pivotable in the radial direction longitudinally or transversely to the axis. Depending on the embodiment, the retaining element can thus be easily and reliably moved into its locking position.

[0024] In an additional preferred embodiment of the coupling device which improves the installation possibility of the coupling device, at least one part of the at least one holding element is movable in a radial direction in a straight line to the axis.

[0025] In a preferred embodiment of the coupling device that improves the installation option of the coupling device, the retaining element has at least partially a claw-shaped, spherical, bolt-shaped, or pin-shaped configuration. This allows for a secure coupling of the conveyor screw shaft to the drive shaft.

[0026] In a further preferred embodiment of the coupling device which increases the safety of the coupling device, the at least one recess of the conveyor screw shaft is a flattening in a part of the circumference of the conveyor screw shaft with an axial extension or a depression therein and / or the at least one elevation extends either only partially or completely over the circumference of the conveyor screw shaft.

[0027] In another preferred embodiment of the coupling device that increases the safety of the coupling device, an inner radius of the ring increases continuously in a predetermined direction along the circumference from a minimum to a maximum value in several equal-sized sections of the circumference, wherein several recesses in the conveyor screw shaft and / or several elevations of the conveyor screw shaft are arranged diametrically or evenly distributed, and wherein several retaining elements are arranged diametrically or evenly distributed. This allows for easy actuation and control of the retaining elements into the locked position in almost any angular position.

[0028] In a preferred embodiment of the coupling device which advantageously reduces wear of the coupling device, the coupling device is free of play in the axial direction.

[0029] In another preferred embodiment of the coupling device which increases the safety of the coupling device, the coupling device has at least one locking element which holds the at least one part of the at least one holding element in the locked state.

[0030] In an embodiment which advantageously increases the safety of the coupling device, the at least one locking element is preferably at least one radial recess in the inner circumference of the ring, into which the at least one part of the at least one holding element is locked in the locked state.

[0031] In a next preferred embodiment of the coupling device which increases the comfort and safety of the coupling device, the locking and / or unlocking of the conveyor screw shaft with the drive shaft can be signaled by a haptic locking signal, colored markings or markings on the ring or a sensor.

[0032] In a further preferred embodiment of the coupling device which improves the comfort and ease of use of the coupling device, the ring has an ergonomic shape of an outer circumference, in particular recesses running parallel to the axis.

[0033] In an embodiment which advantageously increases the safety of the coupling device, the at least one holding element preferably has a first projection running parallel to the axis, into which a second projection of the ring running parallel to the axis engages, wherein an outer radius of the second projection increases continuously in the predetermined direction along the circumference from a minimum to a maximum value at least in a section of the ring circumference.

[0034] The features listed individually in the patent claims can be combined with one another in a technologically meaningful manner and can be supplemented by explanatory facts from the description and by details from the figures, whereby further embodiments of the invention are shown.

[0035] The invention will now be explained in more detail with reference to an embodiment illustrated in the accompanying figures. They show: Fig. 1a an axial plan view of the coupling device from the screw conveyor shaft side in an open position of the coupling device, Fig. 1b an axial plan view of the ring and holding elements of the coupling device in the open position, Fig. 1c a radial sectional view of the coupling device of the plane CC of the Fig. 1a in the open position, Fig. 2a an axial plan view of the coupling device from the screw shaft side in a closed position of the coupling device, Fig. 2b an axial plan view of the ring and holding elements of the coupling device from the screw shaft side in the closed position, Fig. 2c a radial sectional view of the coupling device of the plane FF of the Fig. 2a in the closed position. Description of preferred embodiments

[0036] Before describing the invention in detail, it should be noted that it is not limited to the specific components of the device and the specific method steps, as these components and methods may vary. The terms used herein are intended solely to describe particular embodiments and are not intended to be limiting. Furthermore, when the singular or indefinite articles are used in the description or claims, this also refers to the plural of these elements, unless the overall context clearly indicates otherwise.

[0037] In the Fig. 1a - 1c Shown is a conveyor screw shaft 20, which is connected to a Fig. 1c , 2ccan be coupled to the indicated drive shaft 140, wherein holding elements 30 of the coupling device 10 are shown in an open and unlocked state. The drive shaft 140 can either be integral with a body 60 of the coupling device 10 or connected thereto by means of a connecting device known from the prior art. In the coupled state, in order to lock the conveyor screw shaft 20 to the drive shaft 140, a part 35 of the movable, spring-loaded holding elements 30 of the coupling device 10 can be guided radially toward an axial axis 50 against a projection 40 of the conveyor screw shaft 20. The axis 50 extends through the conveyor screw shaft 20, the coupling device 10, and the drive shaft 140.

[0038] A ring 70, which can be operated manually without tools and is arranged around the body 60 of the coupling device 10 and around the axis 50, is rotatable along a circumference of the ring 70, wherein an inner radius of the ring 70, at least in a section of the circumference, continuously increases in a predetermined direction along the circumference from a minimum to a maximum value. It thus has a wedge-like shape on an inner circumference. The ring 70 is arranged over one of the ends of the holding elements 30 assigned to the conveyor screw shaft 20 and preferably rests with its inner circumference against the holding elements 30 at all times. To lock or unlock the conveyor screw shaft 20 to the drive shaft 140, the ring 70 is rotatable along the circumference in the predetermined direction and the part 35 of each holding element 30 is movable in the radial direction against a spring force.

[0039] The parts 35 of the two holding elements 30 each have a claw-shaped form ( Fig. 1a - 1b , 2a - 2b ), which are guided against the elevation 40 in the form of a circumferential collar of the conveyor screw shaft 20 in the closed and locked state of the holding elements 30, so that sliding out of the conveyor screw shaft 20 from the coupling device 10 in the axial direction is reliably prevented. In Fig. 2a - 2c the holding elements 30 are shown in a closed and locked state.

[0040] Since the torque required to lock or unlock the coupling device 10 is very low, a user can easily lock or unlock the coupling device 10 themselves at any time, even under difficult installation conditions where the coupling device 10 is not visible or where there is limited space for its operation. The ring 70 can also be operated by means of an automatic device within the plastics processing machine.

[0041] As already mentioned, the operating forces required are very low, so that the ring 70 can be operated only by hand and without the use of a tool, which improves the comfort and ease of use of the coupling device 10. However, operation is also possible using a tool, e.g., if the location of the coupling device arrangement is clearly visible and there is sufficient space for operation.

[0042] In an advantageous embodiment of the coupling device 10 that improves the installation option of the coupling device 10, at least one part 35 of the at least one holding element 30 is held by at least one spring 80 either in an unlocked, actuated state away from the axis 50 or in a locked, actuated state toward the at least one recess and / or elevation 40. The spring 80 can thus be designed either as a tension or compression spring. As a result, the ring 70 can be arranged either over the end of the holding elements 30 assigned to the conveyor screw shaft 20 or the drive shaft. If the spring 80 is designed as a compression spring, the ring 70 can also be arranged over the end of the holding elements 30 assigned to the conveyor screw shaft 20.

[0043] In an embodiment that advantageously increases the security of the coupling device 10, the at least one retaining element 30 can have a first projection extending parallel to the axis 50, into which a second projection of the ring 70 extending parallel to the axis 50 engages. An outer radius of the second projection, at least in a portion of the ring circumference, continuously increases from a minimum to a maximum value in the predetermined direction along the circumference. As a result, the retaining elements 30 are, on the one hand, securely held in the locked state and, on the other hand, securely moved away from the axis 50 in the unlocked state against the spring force.

[0044] In an advantageous embodiment improving the installation option of the coupling device 10, at least one part 35 of the at least one holding element 30 is pivotable in the radial direction along or relative to the axis 50. The at least one holding element 30 is designed as a lever and pivots about a pivot axis 120 arranged on the body 60.

[0045] In a preferred embodiment improving the installation possibility of the coupling device 10, the at least one part 35 of the at least one holding element 30 is movable in a radial direction in a straight line to the axis 50.

[0046] In an embodiment that advantageously improves the installation option of the coupling device 10, the holding element 30 has at least partially a claw-shaped, spherical, bolt-shaped, or pin-shaped configuration. When the holding element 30 is arranged in the radial direction along the axis 50, the part 35 of the holding element 30 can be claw-shaped, for example. When the holding element 30 is arranged in the radial direction transverse to the axis 50 or when the holding element 30 is arranged in the radial direction rectilinear to the axis 50, the part 35 can be spherical, bolt-shaped, or pin-shaped, for example. All embodiments have the advantage that the conveyor screw shaft is reliably coupled to the drive shaft 140.

[0047] In an embodiment which advantageously increases the safety and operation of the coupling device 10, the at least one recess of the conveyor screw shaft 20 is a flattened portion in a part of the circumference of the conveyor screw shaft 20 with an axial extension or a depression therein and / or the at least one elevation 40 extends either only partially or completely over the circumference of the conveyor screw shaft 20.

[0048] In an embodiment that advantageously increases the safety of the coupling device 10 and facilitates operability, an inner radius of the ring increases continuously in at least two, preferably in several equal-sized sections of the circumference in a predetermined direction along the circumference from a minimum value of 100 to a maximum value of 110. At least two, preferably several recesses in the conveyor screw shaft 20 and / or at least two, preferably several elevations 40 of the conveyor screw shaft 20 are arranged diametrically or evenly distributed, and at least two, preferably several retaining elements 30 are arranged diametrically or evenly distributed.

[0049] In an embodiment which advantageously reduces the wear of the coupling device 10, the coupling device 10 is free of play in the axial direction.

[0050] In an embodiment of the coupling device 10 that advantageously increases the safety of the coupling device 10, the coupling device 10 has at least one locking element that holds the at least one part of the at least one retaining element 30 in the locked state. Preferably, the at least one locking element is at least one radial recess 90 in the inner circumference of the ring 70, into which the at least one part 35 of the at least one retaining element 30 is engaged in the locked state.

[0051] In an embodiment which advantageously increases the comfort and safety of the coupling device 10, the locking and / or unlocking of the conveyor screw shaft 20 with the drive shaft 140 can be signaled by a haptic locking signal, colored markings or markings on the ring 70 or a sensor.

[0052] In an embodiment advantageously improving the comfort and ease of use of the coupling device 10, the ring 70 has an ergonomic shape of an outer circumference, in particular recesses 130 running parallel to the axis 50. The ring 70 can also have a rubberized layer and / or a ribbing on its outer circumference, which prevents slipping during its operation. List of reference symbols

[0053] 10 Coupling device 20 Conveyor screw shaft 30 Retaining element 35 Part of the retaining element 40 Elevation of the conveyor screw shaft 50 Axial axis 60 Body of the coupling device 70 Ring 80 Spring 90 Radial recess in the inner circumference of the ring 100 Minimum inner radius of the ring 110 Maximum inner radius of the ring 120 Pivot axis of the retaining element 130 Recesses in the outer circumference of the ring 140 Drive shaft

Claims

1. A coupling device (10), configured for a coupling of a screw conveyor and a drive, driving same, of a machine for processing plastics materials and other plastifiable materials, for the positive-locking coupling of a screw conveyor shaft (20) to a drive shaft (140), wherein, in the coupled state, for locking the screw conveyor shaft (20) to the drive shaft (140), at least one part (35) of at least one movable spring-loaded retaining element (30) of the coupling device (10) is insertable into at least one recess of the screw conveyor shaft (20) and / or against at least one projection (40) of the screw conveyor shaft (20) radially in the direction of an axial axis (50), which extends through the screw conveyor shaft (20), the coupling device (10) and the drive shaft (140), wherein a ring (70) arranged around a body (60) of the coupling device (10) and around the axis (50) is rotatable along a circumference of the ring (70), wherein an inner radius of the ring (70) increases continuously in a predetermined direction along the circumference from a minimum (100) to a maximum (110) value at least in a portion of the circumference, wherein the ring (70) is arranged at least partially over the at least one retaining element (30) and abuts with an inner circumference against the retaining element (30), and wherein, for locking or unlocking the screw conveyor shaft (20) with the drive shaft (140), the ring (70) is rotatable in the predetermined direction along the circumference and at least the one part (35) of the at least one retaining element (30) is movable in the radial direction against a spring force, characterised in that the ring (70) can be operated by hand without tools.

2. A coupling device (10) in accordance with claim 1, characterised in that the at least one part (35) of the at least one retaining element (30) is held by at least one spring (80) in an unlocked, removed state away from the axis (50) or in a locked, inserted state towards the at least one recess and / or projection (40).

3. A coupling device (10) in accordance with claim 1 or 2, characterised in that the at least one part (35) of the at least one retaining element (30) is pivotable in the radial direction longitudinally or transversely to the axis (50).

4. A coupling device (10) in accordance with claim 1 or 2, characterised in that the at least one part (35) of the at least one retaining element (30) can be moved in a straight line relative to the axis (50) in the radial direction.

5. A coupling device (10) in accordance with one of the preceding claims, characterised in that the retaining element (30) has at least partially a claw-shaped, spherical, bolt-shaped or pin-shaped form.

6. A coupling device (10) in accordance with one of the preceding claims, characterised in that the at least one recess of the screw conveyor shaft (20) is a flattening in a part of the circumference of the screw conveyor shaft (20) with axial extent or an indentation therein, and / or in that the at least one projection (40) extends either only partially or completely over the circumference of the screw conveyor shaft (20).

7. A coupling device (10) in accordance with one of the preceding claims, characterised in that an inner radius of the ring (70) increases continuously in a predetermined direction along the circumference from a minimum (100) to a maximum (110) value in a plurality of equally sized portions of the circumference, in that a plurality of recesses in the screw conveyor shaft (20) and / or several projections (40) of the screw conveyor shaft (20) are arranged diametrically or equally distributed, and in that a plurality of retaining elements (30) are arranged diametrically or equally distributed.

8. A coupling device (10) in accordance with one of the preceding claims, characterised in that the coupling device (10) is free of play in the axial direction.

9. A coupling device (10) in accordance with one of the preceding claims, characterised in that the coupling device (10) has at least one latching element which holds the at least one part (35) of the at least one retaining element (70) in the locked state.

10. A coupling device (10) in accordance with claim 9, characterised in that the at least one latching element is at least one radial recess (90) in the inner circumference of the ring (70), into which the at least one part (35) of the at least one retaining element (30) is latched in the locked state.

11. A coupling device (10) in accordance with one of the preceding claims, characterised in that the locking and / or unlocking of the screw conveyor shaft (20) with the drive shaft (140) can be signalled by a haptic latching signal, coloured signs or markings on the ring (70) or a sensor.

12. A plastics processing machine comprising a coupling device (10) for a screw conveyor and a drive, driving same, in accordance with one of claims 1 to 11.