WO2024236036A1 - Automatic screwing device, and robot tool - Google Patents

Abstract

The invention relates to an automatic screwing device (1) for screwing belt-guided screws (2) in an automated manner into workpieces, comprising inter alia a conveying device (10) which has at least one conveying pawl (11.1, 11.2) which is mounted in a driven manner such that it can be moved to and fro between an advanced position and a withdrawn position along the advancing direction (V) in repeating cycles, wherein the conveying pawl (11.1, 11.2) has a contact surface (12.1, 12.2) which is designed to come into contact with a transport screw (2b), following the loading screw (2a), of the belt (8), in order to convey the belt (8) within one cycle in the advancing direction (V) by a screw distance (8), and the conveying device (10) has at least one stop pawl (13.1, 13.2) which is designed to hold the loading screw (2a) in its position directly below the screwing bit (6) when the belt (8) which is transported by the conveying pawl (11.1, 11.2) presses the loading screw (2a) against the stop pawl (13.1, 13.2). The invention also relates to a robot tool (28) having automatic screwing devices (1) of this type.

Description

Automatic screwing device and robot tool

The invention relates to an automatic screwing device for the automated screwing of belt-guided screws into workpieces, comprising a motor with a motor shaft to which a bit holder is coupled, which carries a screw bit that can be driven in rotation by the motor and whose axial position is adjustable, for the automatic driving of a screw attached to the screw bit into a workpiece. The invention also relates to a robot tool with several such automatic screwing devices.

DE 10 2012 020 172 A1 describes an automatic screw tightening device that transfers a screw from a screw feed mechanism to a screw tightening mechanism by means of a screw transfer mechanism using air suction of the screw tightening mechanism, that engages the screw with a screw insert portion of a front end of the screw tightening mechanism and that tightens the screw against a predetermined screw range, wherein an output unit is provided at a front end of a transfer hose of the screw feed mechanism, a rotary arm is installed on the output unit, and a feed head unit is installed at a front end of the rotary arm to be brought into close contact with a screw insert portion of a front end of the screw tightening mechanism, the feed head unit between a close contact position, wherein the feed head unit is in close contact with the screw insert portion of the front end of the screw tightening mechanism, and an emptying position is movable with the feed head unit away from the screw bit unit , and in the close contact position the screw bit portion of the front end of the screw tightening mechanism is brought into contact with the screw and sucks a head portion of the screw to be engaged with the screw .

The object of the invention is to create an automatic screwing device by means of which screws can be screwed into workpieces with a high screwing performance and high process reliability. A further object is to create a robot tool in order to be able to handle several automatic screwing devices together automatically.

The task is solved by an automatic screwing device for the automated screwing of belt-guided screws into workpieces, comprising:

- a motor with a motor shaft to which a bit holder is coupled, which carries a screw bit which can be driven in rotation by the motor and which is adjustable in its axial position, for automatically driving a screw attached to the screw bit into a workpiece,

- a loading device for feeding a belt on which several screws are pre-assembled at equal distances from one another and in parallel alignments to one another, wherein the loading device has a guide on which the screws are guided in such a way that a respective foremost one in the feed direction Loading screw can be fed into a position immediately below the screw bit by pushing the belt forward, and wherein the loading device has a conveyor device which is designed to transport the belt within the guide, and wherein

- the conveyor device has at least one conveyor pawl which is mounted so as to be movable back and forth in repeated cycles between an advance position and a retraction position along the feed direction, wherein the conveyor pawl has a contact surface which is designed to bear against a transport screw of the belt following the loading screw in order to convey the belt by one screw spacing within one cycle in the feed direction, and the conveyor device has at least one stop pawl which is designed to hold the loading screw in its position immediately below the screw bit when the belt transported by the conveyor pawl presses the loading screw against the stop pawl.

The motor can be an electric motor, for example. In addition to the motor shaft and the bit holder, the motor or a drive unit that includes the motor can have other components. The drive unit can be designed in the manner of a drywall screwdriver known per se. If necessary, commercially available drywall screwdrivers can be used for an automatic screwing device according to the invention. It can also be provided, for example, that the a commercially available drywall screwdriver is modified so that it can be operated in fully automatic mode, for example automatically controlled by a separate drive control. For example, a handle can be removed from the commercially available drywall screwdriver, a manual on/off switch and/or, if applicable, a manual direction of rotation switch can be removed. The electric motor of the drywall screwdriver modified in this way can then be attached to a height-adjustable carriage of the screw device according to the invention. Such height adjustability of the carriage relates to the longitudinal extent of the screw bit, i.e. to the axis of rotation about which the motor rotates the screw bit. The height adjustability of the carriage relates to a vertical alignment of the motor or the motor shaft, with the screw bit with its screw profile in this case pointing downwards.

The carriage can be mounted on a base frame of the screwing device in an automatically adjustable manner by a linear drive. The linear drive can, for example, comprise a pneumatic cylinder which is supplied with compressed air, and electrically controllable valves can be provided in order to be able to control the pneumatic cylinder automatically via a control device, so that the screw bit driven by the motor can be automatically adjusted in the axial direction, i.e. can be advanced and retracted again. The screw bit can be interchangeably accommodated in the bit holder. Depending on the screw size and screw head profile, different types of screw bits can be optionally inserted into the bit holder and used in conjunction with a belt that carries screws that match the screw bit.

The motor drives the bit holder and consequently the screw bit so that a screw can be turned automatically when the screw bit engages the screw head profile of a screw. The motor, or the bit holder and the screw bit, are driven forward by means of a feed movement by the linear drive so that a screw attached to the screw bit is driven into the workpiece while the motor and the screw bit rotate the screw.

In the screwing device according to the invention, the screws, which can be connected by means of a belt, are to be fed automatically so that the screwing device can automatically drive screws into one or more workpieces in cycles. A loading device and a conveyor device are provided for automatic feeding.

The loading device holds and guides the screws directly, for example by guiding the screws along the surfaces beneath the screw heads, or the loading device holds and guides the belt that carries the screws. The screws are driven directly from the belt into the workpiece by the motor-driven screw bit. The screws are therefore not fed to the screw bit one at a time. Rather, the belt is guided toward the screw bit by the loading device so that the foremost screw on the belt, the so-called loading screw, is positioned directly beneath the screw bit. For this purpose, the loading device has a guide along which the belt is guided. The guide can, for example, have two opposing strips which guide or hold the belt from two opposite sides. At least one of the two strips can have a strip shoulder on which the belt can rest and is guided on a linear feed path so that the screws, which are pre-assembled on the belt at equal screw spacings from one another and in parallel alignment to one another, can be fed in line with the axial extension of the screw bit. In a feed position, the foremost loading screw is then positioned directly below the screw bit, with the screw head directly next to the screw bit, so that the profile of the screw bit can fit positively into the matching screw head profile when the screw bit is moved axially downwards towards the screw.

The guides can be detachably attached to a base body of the screwing device. For example, the guides can be screwed to the base body. Due to a detachable attachment, in particular by means of screws, the guides can be easily replaced. This can be necessary in particular if the automatic screwing device is to be converted to a different type of screw. Depending on the type of screw head, the screw head profile and/or the diameter and/or possibly the length of the screws, it may be necessary to replace the guides.

According to the invention, the screws are moved in the feed direction by the conveyor device with the belt carrying the screws by the conveyor device has at least one conveyor pawl, which with its contact surface directly contacts a screw held on the belt and pushes this forwards in the feed direction. When the screw is pushed, the entire belt and the other screws held on it are also moved. The conveyor device, i.e. the at least one conveyor pawl, does not grip the belt itself, but only a screw on the belt.

The conveyor device or the at least one conveyor pawl works in cycles, i.e. in each cycle the belt is conveyed forwards by one screw spacing in the feed direction. After a first loading screw has been automatically screwed into the workpiece using the screw bit, the previous support point of the loading screw on the belt is emptied and the next screw is conveyed forwards by the screw spacing in the feed direction so that a new loading screw is again positioned directly below the screw bit. So that the conveyor device or the at least one conveyor pawl can convey the belt forwards by a further screw spacing in the feed direction, the at least one conveyor pawl is moved back again by one screw spacing against the feed direction. The at least one conveyor pawl jumps over a transport screw following the loading screw on the belt in order to get behind this transport screw, so that the at least one conveyor pawl can reach behind this loading screw with its contact surface in order to convey this transport screw forwards by one screw spacing in the feed direction in a new cycle step. A screw preceding the transport screw in the feed direction forms the loading screw. The at least one conveyor pawl The contact surface does not engage the screw that is moved directly under the screw bit and thus forms the loading screw. Rather, the at least one conveyor pawl engages the contact surface of a screw that follows on the belt, which then forms a transport screw that is different from the loading screw.

The at least one stop pawl specifies the position in which the loading screw is located centrally under the screw bit, so that merely by a linear movement of the screw bit in the axial direction towards the loading screw, the profile of the screw bit can engage in a form-fitting manner with the screw head profile of the loading screw.

The at least one stop pawl can be adjustably mounted on the loading device. By means of an adjustable mounting, the stop pawl can be adapted to different types of screws and/or different sizes of screws. The at least one stop pawl can in particular be pivotably mounted.

In a special embodiment, the conveyor device can have a first conveyor pawl which is designed and mounted in such a way that a first contact surface of the first conveyor pawl directly engages a shaft section of the adjacent transport screw which is exposed above the belt during the feed movement, and the conveyor device can have a second conveyor pawl which is designed and mounted in such a way that a second contact surface of the second conveyor pawl directly engages a shaft section of the adjacent transport screw which is exposed below the belt during the feed movement. As the conveyor device has the first conveyor pawl and the second conveyor pawl at a distance from it, a transport screw can be perpendicular to its

Longitudinal extension. Due to the two spaced-apart attack points of the first conveyor pawl and the second conveyor pawl on the transport screw, it is ensured that the screw maintains its orientation with its longitudinal extension perpendicular to the feed direction and in particular does not tip over or become jammed. The distance between the first conveyor pawl and the second conveyor pawl can be adapted to the total length of the screws to be used on the belt. The first conveyor pawl can contact the screw below the screw head, for example, and the second conveyor pawl can contact the screw from the free end of the screw tip, for example. The belt can connect the several screws in a middle section of the respective screw shafts. The belt runs in the intermediate area between the first conveyor pawl and the second conveyor pawl, guided directly along the at least one guide of the loading device or indirectly via the screws, which can be guided by means of their screw heads along the at least one guide of the loading device.

The at least one conveyor pawl can be pre-tensioned into its conveyor positions by means of a spring, such that when the conveyor pawl is moved back from the feed position to the retraction position against the feed direction, the conveyor pawl slides over a shaft section of a follower screw following the transport screw, in that the conveyor pawl can move transversely to the feed direction in order to move the follower screw to be able to bypass it so that at least one contact surface can come into contact with the following screw from behind in order to form the loading screw from the transport screw in the next cycle.

In an analogous manner, in the case of two conveyor pawls, it can be provided that the first conveyor pawl and the second conveyor pawl can be pre-tensioned into their conveyor positions by means of at least one spring each, such that when the first conveyor pawl and the second conveyor pawl move back from their advance positions to their retraction positions against the feed direction, the first conveyor pawl and the second conveyor pawl slide over a shaft section of a follow-up screw following the transport screw, in that the first conveyor pawl and the second conveyor pawl can deviate transversely to the feed direction in order to be able to bypass the transport screw, so that the first contact surface and the second contact surface can come into contact with the follow-up screw in order to form the loading screw in the next cycle.

The at least one conveyor pawl, in particular the first conveyor pawl and the second conveyor pawl, can be mounted pivotably about a pivot axis on a base body of the loading device. The respective spring can have a spring coil section that can be positioned coaxially to the pivot axis, wherein a first spring leg adjoining the spring coil section can be supported against the respective conveyor pawl and a second spring leg adjoining the spring coil section opposite can be supported against the base body.

The loading device can be inserted into a guide channel of the

spring-loaded locking pawl protruding into the loading device which is designed and mounted in such a way that when the belt moves forwards in the feed direction, the locking pawl is pressed out of the guide channel against its spring preload by a forwardly fed screw and when the conveyor pawl, in particular the first conveyor pawl and the second conveyor pawl, moves back from the feed position into the retraction position against the feed direction, the locking pawl projects into the guide channel in order to prevent the belt from moving back.

If, for example, the guide has two opposing strips which guide or hold the screw heads or the belt from two opposite sides, the space above and/or below the two opposing strips forms the respective guide channel for the screws. The pawl therefore acts directly on the respective screw shaft of a screw. The pawl therefore does not act directly on the belt.

The locking pawl can, for example, comprise a pivot lever which is pivotably mounted on the base body of the loading device. The pivot lever can have a locking lug which has a front surface pointing in the feed direction. The front surface can be aligned at least substantially perpendicular to the feed direction. The locking lug can have a rear surface opposite the front surface which can be aligned obliquely to the feed direction. The rear surface of the locking lug can be inclined in such a way that when a screw is conveyed forwards by means of the conveying device, a screw shaft of a subsequent screw can slide along the rear surface of the locking lug, whereby the Feed movement of the screw, which presses against the rear surface of the locking lug, the locking lug is pressed outwards against its spring preload so that the screw in question can pass the locking lug.

If a screw which has already passed the locking lug is pulled back by the belt, possibly against the conveyor system in the feed direction, the screw shaft of the screw which has passed through runs against the front surface of the locking lug. As the front surface is arranged perpendicular to the feed direction, the screw shaft cannot push the locking lug out of the guide channel, but rather runs directly onto the front surface of the locking lug without the locking lug or the pivot lever moving. This prevents the belt from running back against the feed direction. If the locking pawl is designed as a pivot lever, the front surface can be at least approximately aligned with the pivot axis, so that when pressure is applied to the front surface, no torque at all or at most a very slight torque is induced, which is less than the minimum torque that would be required to push the locking pawl out of the guide channel.

The at least one stop pawl can be adjustable between a holding position in which the loading screw is held in its position immediately below the screw bit and a release position in which the stop pawl is moved out of the guide channel in such a way that the loading screw can be moved further forwards in the feed direction from its position immediately below the screw bit. In a first embodiment, the at least one stop pawl can be driven or controlled and adjustable. In a second embodiment, the at least one stop pawl can be spring-loaded into the holding position. Such a spring-loaded mounting of the stop pawl therefore requires no drive and no additional drive energy to move the stop pawl.

In a special embodiment, two stop pawls can be provided. One stop pawl can be located to the right or left of the loading screw. The stop pawls can in particular be designed and arranged in such a way that when a conveying movement in the feed direction is generated by the conveying device, the stop pawls cause the loading screw to strike in its head area. The belt is guided past the stop pawls without contact, so that a belt section which no longer has any screws is not stopped by the stop pawls, but is conveyed further in the feed direction by the conveying device or by the at least one conveying pawl indirectly via a screw which is resting on the contact surface and is still on the belt, past the position of the screw bit.

In the case of a spring-loaded bearing, the stop pawls can be preloaded with such a spring force that a loading screw is positioned precisely by means of the stop pawls, i.e. axially aligned with the screw bit on the stop pawls when at least one conveyor pawl has moved the transport screw into the feed position. By means of a sensor, in particular an optical sensor such as a camera, the loading screw can be automatically checked in the feed position adjacent to the stop pawls to see whether the screw presented as the loading screw is OK, i.e. for example whether the screw shaft has the correct length, the screw shaft is straight, the thread on the screw shaft is complete and error-free and/or the screw head is error-free. The automatic check can be carried out, for example, by means of an image analysis on a control device which can automatically control the screwing device. By means of a sensor, in particular an optical sensor such as a camera, it can also be automatically checked whether the loading device or the belt is still loaded with screws.

If a screw presented as a loading screw is classified as not OK, i.e. as faulty, the screw bit is not operated and the screw presented as a loading screw is not used, i.e. is not automatically screwed into the workpiece. Rather, the screw bit remains in its holding position and the feed pawl is instead moved by an additional cycle so that a subsequent screw is presented as a new loading screw and the screw classified as faulty is automatically transported forwards past the stop pawls. In doing so, the screw overcomes the spring force of the stop pawls so that the stop pawls are moved out of the guide channel, in particular are swung out. After the screw classified as faulty has left the loading position, the stop pawls close due to the spring preload. automatically again and the previous transport screw is presented as a new loading screw striking the stop pawls. If this new screw is recognized as fault-free during a new optical evaluation and can therefore be used as a loading screw, the screw bit starts and drives the loading screw into the workpiece.

The guide can be attached to a base body of the loading device in an exchangeable manner. The guides can thus be detachably attached to the base body of the screwing device. For example, the guides can be screwed to the base body. Due to a detachable attachment, in particular by means of screws, the guides can be easily replaced. This can be necessary in particular if the automatic screwing device is to be converted to use a different type of screw. Depending on the type of screw head, the screw head profile and/or the diameter and/or possibly the length of the screws, it may be necessary to replace the guides.

The loading device can have a seat on its base body in which a centering bush is fastened, in particular in an interchangeable manner, wherein the centering bush forms a centering guide for the screw bit in order to align the screw bit in a coaxial alignment with respect to the loading screw.

The shaft of the screw bit is guided in the centering bushing so that the screw bit can move in the axial direction through the centering bushing, but is supported and guided in the radial direction by the centering bushing. The centering bushing prevents the shaft of the screw bit from swinging or swinging. The centering bushing This ensures that the profile of the screw bit is always aligned coaxially with the corresponding screw head profile of the screw. When the profile of the screw bit engages the screw head profile of the screw, the screw to be screwed in is also stabilized and held in its axial alignment.

The centering bushing is adapted to the type and size of the screw bit. In particular, the centering bushing is adapted to the diameter of the shaft of the screw bit. If the screwing device is to be able to screw in other types of screws automatically, then a screw bit adapted to the type of screw must always be used and the centering bushing must therefore also be adapted to the changed screw bit. The centering bushing can be screwed into the seat. Alternatively, the centering bushing can also be detachably attached to the seat in another way, for example by means of a locking device.

The automatic screwing device can be equipped with a drum magazine. The drum magazine can have:

- a drum axle designed to wind up a belt on which a large number of screws are pre-assembled at equal distances from one another and in parallel alignments to one another,

- a first limiting disc arranged at one end of the drum axis and a second limiting disc arranged at the other end of the drum axis, wherein at least the first limiting disc and/or the second limiting disc is mounted axially displaceably on the drum axis for adaptation to different screw lengths and/or screw sizes.

The drum magazine can be mounted on the automatic screwing device in an exchangeable manner. A rolled-up belt can be stored in such a drum magazine. The belt can, for example, carry several hundred or thousand screws.

By mounting at least the first limiting disk and/or the second limiting disk on the drum axis so that it can be axially displaced to adapt to different screw lengths and/or screw sizes, the drum magazine can be optionally loaded with different types and/or sizes of screws. By displacing at least one of the two limiting disks, the distance between the two opposing limiting disks can be specifically adapted to the screw length used.

The loading device can have a knife guide which is designed to guide a cutting blade of a cutting device which is designed to automatically separate a section of webbing which has passed through the loading device and/or is empty from the belt.

After a certain number of screws have been automatically removed from the belt by means of the screwing device and screwed into the desired workpiece, a certain empty part of the belt is also fed out of the loading device of the screwing device. In order for this empty part of the belt to be able to continue In order to ensure that the screws are not disturbed during the processing process, a separating device, in particular a cutting device, can be provided which, after removing a predetermined number of screws from the belt, separates a corresponding, in particular empty, part of the belt from the remaining belt and thus removes it from the screwing device. The predetermined number of screws can be flexibly adjustable, i.e. can be specified. The screws processed are automatically counted accordingly.

The separating device or the cutting device can be arranged as a component of the screwing device directly on the screwing device, in particular on the loading device. Alternatively, the separating device or the cutting device can also be set up separately from the screwing device, for example as a stationary separating device or cutting device. If the screwing device is automatically guided and moved by a robot arm, for example, the screwing device can be moved up to the stationary separating device, the separating device can cut off an empty partial length of the belt there and the screwing device can then be moved back by the robot arm to its actual work station where the screws are to be screwed into the workpieces. The empty partial lengths of the belt cut off at the stationary separating device can fall into a collecting container so that they can be disposed of or recycled.

The separating device in the form of a cutting device can have a cutting blade that can be moved automatically by a drive. The cutting blade can be moved along the knife guide of the loading device so that the knife can cross the path of movement of the empty partial lengths of the belt. The cutting blade can be moved against a fixed counter-holding plate so that the empty partial lengths of the belt come to rest between the counter-holding plate and the cutting blade and can be cut off there.

The object is also achieved by a robot tool, having a base support, a tool flange arranged on the base support, which is designed to fasten the robot tool to a connection flange of a robot arm, and having a plurality of mounting supports arranged on the base support, which are each designed to individually fasten an automatic screwing device according to one of the described embodiments.

The robot tool can accordingly have at least one automatic screwing device according to one of the described embodiments. It is expedient if the robot tool has several automatic screwing devices according to one of the described embodiments. The several automatic screwing devices can be attached or mounted on the robot tool in a desired arrangement. For example, several automatic screwing devices can be arranged next to one another in a row. The screwing devices can be arranged at equal distances from one another. For example, several screws can be screwed into the workpiece simultaneously in a line at desired distances from one another. The workpiece can, for example, be a drywall panel or several drywall panels.

The workpiece can also be a sheet metal or several sheets of metal, or lightweight steel frames that are to be screwed together with self-tapping sheet metal screws.

Because the base support of the robot tool has several mounting supports, different numbers of screw devices can be optionally attached to the base support. The mounting supports can also be adjustably mounted on the base support, so that the relative distances between two immediately adjacent mounting supports or screw devices can be adjustable, i.e. changeable.

The robot tool can be designed in such a way that the attached screw devices can be operated in any orientation, i.e. orientation in space. It can even be provided that the multiple screw devices of the robot tool can be operated "overhead", i.e. for example screws can be screwed into the workpiece in a screwing direction from bottom to top, whereby the screws are screwed into an underside of the workpiece.

The tool flange of the robot tool can have all electrical, pneumatic or hydraulic connectors or plug-in couplings so that all mounted screw devices can be supplied with the required type of energy in order to be able to control the screw devices automatically.

The connection flange of a robot arm can accordingly have corresponding electrical, pneumatic or hydraulic mating connectors or mating couplings so that the robot tool can be connected to the robot arm can be coupled and the mounted screw devices can be supplied with the required type of energy via the robot arm.

The screwing devices can be automatically controlled by a separate control system via the robot arm. The separate control system for automatically controlling the screwing devices can be synchronized with a robot control system that automatically controls the movements of the robot arm. The separate control system and the robot control system can be designed as separate, independent control devices. Alternatively, the separate control system and the robot control system can be combined in a common process control system and, if necessary, even combined in a single control computer.

A specific embodiment of the invention is explained in more detail in the following description with reference to the attached figures. Regardless of the specific context in which they are mentioned, specific features of this exemplary embodiment can also represent general features of the invention, if appropriate also considered individually or in further combinations.

They show:

Fig. 1 is a perspective view of an automatic

Screwing device with raised

screw bit,

Fig. 2 is a perspective view of the automatic Screwing device according to Fig. 1 with lowered screw bit,

Fig. 3 is a perspective view of the

Loading device in a stand-alone position with a screw-carrying belt,

Fig. 4 is a perspective view of the

Loading device according to Fig. 3 from its rear side,

Fig. 5 is a perspective view of the

Loading device according to Fig. 3 from its front side,

Fig. 6 a top view of the

funding institution of the

Screw device according to Fig. 3 with the conveyor pawl in the retracted position,

Fig . 7 a top view of the

funding institution of the

Screwing device according to Fig. 3 with the feed pawl in the feed position,

Fig. 8 a top view of the

funding institution of the

Screw device according to Fig. 3 with the conveyor pawl during a

Returning the conveyor pawl from the feed position to the

retreat position, Fig. 9 a top view of the

funding institution of the

Screw device according to Fig. 3 with opened stop pawls,

Fig. 10 is a partial perspective view of the automatic screwing device with a knife guide and a cutting device in a

custody position,

Fig. 11 is a partial perspective view of the automatic screwing device with a knife guide and a cutting device in a

cutting position,

Fig. 12 is a perspective view of a

robot tool with several automatic screwing devices,

Fig. 13 is a perspective view of an automatic screwing device with a drum magazine for a belt carrying screws,

Fig. 14 a perspective view of the

Loading device in a stand-alone position with an inserted belt that carries the screws, Fig. 15 a perspective view of the

drum magazine in a unique position from behind, and

Fig. 16 an exploded view of the

Drum magazine according to Fig. 15 in a unique position from the front.

Fig. 1 shows an automatic screwing device 1. The automatic screwing device 1 is used for the automated screwing of belt-guided screws 2 (Fig. 3, Fig. 14) into workpieces.

The automatic screwing device 1 has a motor 3 with a motor shaft 4 to which a bit holder 5 is coupled, which carries a screw bit 6 that can be driven in rotation by the motor 3 and whose axial position is adjustable in the direction of arrow PI, for automatically driving a screw 2 attached to the screw bit 6 into a workpiece.

The automatic screwing device 1 has a loading device 7 for feeding a belt 8 (Fig. 3, Fig. 14) on which several screws 2 are pre-assembled at equal screw spacings A from one another and in parallel alignments to one another, wherein the loading device 7 has a guide 9 (Fig. 5) on which the belt 8 carrying the screws 2 is guided in such a way that a loading screw 2a which is at the front in the feed direction V can be fed into a position immediately below the screw bit 6 by pushing the belt 8 forward, wherein the loading device 7 has a conveyor device 10 (Fig. 4 to Fig . 9 ) which is designed to transport the belt 8 within the guide 9 .

The guide 9 is fastened to a base body 18 of the loading device 7 on opposite sides in an exchangeable manner, as shown in Fig. 5 on one side of the loading device 7. The guide 9 is detachably screwed to the base body 18 via fastening screws 19.

The motor 3 together with the bit holder 5 , the screw bit 6 and the screwdriver carriage 40 forms a screw unit.

The screw unit also comprises a stop 41 which defines the screw-in depth of a screw 2. The stop 41 is attached to the feed unit 42 which carries the loading device 7. The counterpart 43 to the stop 42 is attached to the screw unit. If the counterpart 43 and the stop 41 come into contact with one another, as shown in Fig. 2, the screw unit cannot move any further in the direction of the workpiece and the screw bit 6 disengages from the screw 2 via a drywall coupling when the screw-in depth is reached.

Because in the case of the present embodiment, for example, a pressure sensor is used as a fixed stop 41, it can be determined automatically whether the screw 2 has reached the desired screw-in depth and, consequently, in view of the expected height position or height difference, the screw 2 has been screwed in correctly.

If, in the event of a fault, for example, screw 2 has not been tightened, this can be automatically evaluated by the control system. because in this case the signal that the stop 41 has been reached comes too early and therefore no screw 1 has been turned. This incorrect screw position can therefore automatically be assessed as not being OK.

Since the stop 41 is mounted on the feed unit 42, it does not have to be adjusted mechanically, since the feed unit 42 always rests on the workpiece. Only the desired screw-in depth of the screw 2 has to be set on the counterpart 43.

Fig. 2 shows how the stop 41 and the counterpart 43 lie against each other.

The conveyor device 10 has at least one conveyor pawl 11.1, 11.2, which is mounted so as to be movable back and forth in repeated cycles along the feed direction V between a feed position (Fig. 7) and a retraction position (Fig. 6), wherein the conveyor pawl 11.1, 11.2 has a contact surface 12.1, 12.2, which is designed to rest against a transport screw 2b of the belt 8 following the loading screw 2a in order to convey the belt 8 within one cycle in the feed direction V by a screw spacing A, and the conveyor device 10 has at least one stop pawl 13.1, 13.2, which is designed to hold the loading screw 2a in its position immediately below the screw bit 6 when the belt 8 transported by the conveyor pawl 11.1, 11.2 pushes the loading screw 2a against the stop pawl 13.1, 13.2 presses.

In the case of the present embodiment, the conveyor device 10 has a first conveyor pawl 11.1, which is designed and mounted in such a way that a first contact surface 12.1 of the first conveyor pawl 11.1 during the Feed movement directly engages a shaft section 2.1 of the adjacent transport screw 2b which is exposed above the belt 8 and the conveyor device 10 has a second conveyor pawl 11.2 which is designed and mounted in such a way that a second contact surface 12.2 of the second conveyor pawl 11.2 directly engages a shaft section 2.2 of the adjacent transport screw 2b which is exposed below the belt 8 during the feed movement.

In the case of the present embodiment, both the first conveyor pawl 11.1 and the second conveyor pawl 11.2 are pre-tensioned into their conveyor positions (Fig. 6, Fig. 7) by means of at least one spring 14 in each case, such that when the first conveyor pawl 11.1 and the second conveyor pawl 11.2 are moved back from the feed position (Fig. 7) to the retraction position (Fig. 6) in a returning direction of movement R against the feed direction V, the first conveyor pawl 11.1 and the second conveyor pawl 11.2 slide over a shaft section 2.1, 2.2 of a follower screw 2c following the transport screw 2b, as is shown in particular in Fig. 8, in that the first conveyor pawl 11.1 and the second conveyor pawl 11.2 can deviate in a transverse direction Q transverse to the feed direction V in order to move the follower screw 2c so that the first contact surface 12.1 and the second contact surface 12.2 can come into contact with the following screw 2c from behind in order to form the loading screw 2b in the next cycle.

In the case of the present embodiment, the loading device 7 has a spring-loaded locking pawl 16 which projects into a guide channel 15 of the loading device 7 and is designed and mounted in such a way that that when the belt 8 moves forward in the feed direction V, the locking pawl 16 is pressed out of the guide channel 15 by a screw 2 fed forwards against its spring preload of the spring means 17, and when the first feed pawl 11.1 and the second feed pawl 11.2 move back from the feed position (Fig. 7) into the retraction position (Fig. 6) against the feed direction V, the locking pawl 16 projects into the guide channel 15 in order to prevent the belt 8 from moving back, in that the upstream screw 2, 2c rests on the locking pawl 16.

The stop pawls 13.1, 13.2 are adjustable between a holding position (Fig. 6 to 8), in which the loading screw 2a is held in its position immediately below the screw bit 6, and a release position (Fig. 9), in which the stop pawls 13.1, 13.2 are moved out of the guide channel 15 such that the loading screw 2a can be moved further forwards in the feed direction V from its position immediately below the screw bit 6.

In the case of a spring-loaded bearing, the stop pawls 13.1, 13.2 can be preloaded by means of the compression spring pins 20 with such a spring force that a loading screw 2a is positioned precisely by means of the stop pawls 13.1, 13.2, i.e. axially aligned with the screw bit 6 on the stop pawls 13.1, 13.2 when the at least one conveyor pawl 11.1, 11.2 has moved the transport screw 2b into the feed position.

If a screw 2 presented as a loading screw 2a is classified as not OK, ie as faulty, the screw bit 6 is not operated and the screw 2 presented as a loading screw 2a is not used, ie not automatically screwed into the workpiece. Rather, the screw bit 6 remains in its holding position and the feed pawls 11.1, 11.2 are instead moved by an additional cycle, so that a subsequent screw 2, the transport screw 2b, is presented as a new loading screw 2a and the screw 2 classified as faulty is pushed forwards past the stop pawls

13.1, 13.2, as shown in Fig. 9. The screw 2 overcomes the spring force of the compression spring pins 20 of the stop pawls 13.1,

13.2, so that the stop pawls 13.1, 13.2 are moved out of the guide channel 15, in particular are pivoted out. After the screw 2 classified as faulty has left the loading position, the stop pawls 13.1, 13.2 close again automatically due to the spring preload and the previous transport screw 2b is presented as the new loading screw 2a striking the stop pawls 13.1, 13.2.

Returning to Fig. 3, the loading device 7 can have on its base body 18 a seat 21 in which a centering bushing 22 is replaceably fastened, wherein the centering bushing 22 forms a centering guide for the screw bit 6 in order to align the screw bit 6 in a coaxial alignment with respect to the loading screw 2a.

As shown in Fig. 10 and Fig. 11, the loading device 7 can have a knife guide 23 which is designed to guide a cutting blade 24 of a cutting device 25 which is designed to automatically separate a belt section which has passed through the loading device 7 and/or is empty from the belt 8. The cutting device 25 can, as shown in Fig. 10 and Fig. 11 is shown as a component of the

Screwing device 1 can be arranged directly on the screwing device 1, in particular on the loading device 7.

The cutting device 25 can have a cutting blade 24 which can be moved automatically by a drive 26. The cutting blade 24 can be guided along the knife guide 23 of the loading device 7 so that the cutting blade 24 can cross the path of movement of the empty partial lengths of the belt 8. The cutting blade 24 can be moved against a fixed counter-holding plate 27 so that the empty partial lengths of the belt 8 come to lie between the counter-holding plate 27 and the cutting blade 24 and can be cut off there. Fig. 10 shows the cutting blade 24 in its non-cutting position and Fig. 11 shows the cutting blade 24 in its cutting position.

Fig. 12 shows a robot tool 28, having a base support 29, a tool flange 30 arranged on the base support 29, which is designed to fasten the robot tool 28 to a connection flange of a robot arm (not shown), and having a plurality of, in the case of the present embodiment eight, mounting supports 31 arranged on the base support 29, which are designed to individually fasten an automatic screwing device 1 according to one of the described embodiments.

Fig. 13 additionally shows a drum magazine 32 mounted on the automatic screwing device 1. The drum magazine 32 is shown in more detail in Fig. 15 and Fig. 16. The drum magazine 32 has a drum axis 33 which is designed for winding up a belt 8 ( Fig. 14 ) on which a plurality of screws 2 are prefabricated at equal screw spacings A from one another and in parallel alignments to one another.

The drum magazine 32 has a first limiting disk 34.1 arranged at one end of the drum axis 33 and a second limiting disk 34.2 arranged at the other end of the drum axis 33, wherein at least the first limiting disk 34.1 and/or the second limiting disk 34.2 is mounted axially displaceably on the drum axis 33 for adaptation to different screw lengths and/or screw sizes. For this purpose, several locking seats 35 can be provided on the drum axis 33. The second limiting disk 34.2 can be detachably attached to the drum axis 33 as shown. The drum magazine 32 can have a carrying handle 36.

Returning to Fig. 1, the loading device 7 can be mounted on the same rails as the motor 3 or on separate rails 38 by means of a slide 37 relative to the motor 3 and thus relative to the screw bit 6 in the direction of arrow P2, so that it can be displaced in height relative to the motor 3, or on separate rails 38. For this purpose, the slide 37 can be pre-tensioned downwards by means of an air spring 39. Thus, by a joint movement of the screw device 1 towards the workpiece, for example in Fig. 1 in a downward direction, the loading device 7 can first sit on the workpiece, whereby the motor 3 and the screw bit 6 can be moved further downwards against the spring force of the air spring 39, without the screw bit 6 first engaging a screw 2 in a form-fitting manner. In the case of the present embodiment, the air spring 39 is on a Base plate attached and therefore independent of the

Movement of the screw bit 6. The air spring 39 ensures that the loading device 7 always lies flush against the workpiece. The air spring 39 is automatically moved downwards so that the screwdriver and feed unit are apart. The robot presses the air spring 39 in slightly after it has been placed on the workpiece. The air spring 39 ensures that the loading device 7 is not lifted by the screwing forces when screwing. The end position of the air spring 39 should not be reached, since otherwise the screw bit 6 would sink too deeply and an emergency stop would be triggered to protect the devices (crash protection).

If, for example, several screwing devices 1 are provided on the robot tool 28, each individual screwing device 1 can be placed on a surface of the workpiece independently of the other screwing devices 1. In the case of uneven workpieces, the several screwing devices 1 can therefore assume different heights. Only then is the motor unit, comprising the motor 3, the bit holder 5 and the screw bit 6, moved downwards so that the screw bit 6 can be placed on the associated screw head of a supplied screw 2 and the loading screw 2a can be driven into the workpiece by a feed movement of the motor 3, the bit holder 5 and the screw bit 6 while simultaneously rotating the loading screw 2a.

Claims

patent claims 1. Automatic screwing device for the automated screwing of belt-guided screws (2) into workpieces, comprising: - a motor (3) with a motor shaft (4) to which a bit holder (5) is coupled, which carries a screw bit (6) which can be driven in rotation by the motor (3) and which is adjustable in its axial position, for automatically driving a screw (2) attached to the screw bit (6) into a workpiece, - a loading device (7) for feeding a belt (8) on which a plurality of screws (2) are prefabricated at equal screw spacings (A) from one another and in parallel alignments to one another, wherein the loading device (7) has a guide (9) on which the screws (2) are guided in such a way that a loading screw (2a) which is at the front in the feed direction (V) can be fed into a position immediately below the screw bit (6) by pushing the belt (8) forward, and wherein the loading device (7) has a conveyor device (10) which is designed to transport the belt (8) within the guide (9), and wherein - the conveyor device (10) has at least one conveyor pawl (11.1, 11.2) which is mounted so as to be movable back and forth in repeated cycles between a feed position and a retraction position along the feed direction (V) wherein the conveyor pawl (11.1, 11.2) has a contact surface (12.1, 12.2) which is designed to rest on a transport screw (2b) of the belt (8) following the loading screw (2a) in order to convey the belt (8) within one cycle in the feed direction (V) by a screw spacing (A), and the conveyor device (10) has at least one stop pawl (13.1, 13.2) which is designed to hold the loading screw (2a) in its position immediately below the screw bit (6) when the belt (8) transported by the conveyor pawl (11.1, 11.2) presses the loading screw (2a) against the stop pawl (13.1, 13.2). 2. Automatic screwing device according to claim 1, characterized in that the conveyor device (10) has a first conveyor pawl (11.1) which is designed and mounted in such a way that a first Contact surface (12.1) of the first conveyor pawl (11.1) directly engages a shaft section (2.1) of the adjacent transport screw (2b) exposed above the belt (8) during the feed movement, and the conveyor device (10) has a second conveyor pawl (11.2) which is designed and mounted in such a way that a second contact surface (12.2) of the second conveyor pawl (11.2) directly engages a shaft section (2.2) of the adjacent transport screw (2b) exposed below the belt (8) during the feed movement. 3. Automatic screwing device according to claim 1 or 2, characterized in that the conveyor pawl (11.1, 11.2), in particular the first conveyor pawl (11.1) and the second conveyor pawl (11.2), are pre-tensioned into their conveyor positions by means of at least one spring (14), such that when the conveyor pawl (11.1, 11.2), in particular the first conveyor pawl (11.1) and the second conveyor pawl (11.2), are moved back from the feed position into the retraction position against the feed direction (V), the conveyor pawl (11.1, 11.2), in particular the first conveyor pawl (11.1) and the second conveyor pawl (11.2), slides over a shaft section of a follower screw (2c) following the transport screw (2b), in that the conveyor pawl (11.1, 11.2), in particular the first conveyor pawl (11.1) and the second conveyor pawl (11.2) transversely to the feed direction (V) in order to be able to bypass the following screw (2c), so that the at least one contact surface (12.1, 12.2), in particular the first contact surface (12.1) and the second contact surface (12.2) can come into contact with the following screw (2c) from behind in order to form the loading screw (2b) in the next cycle. 4. Automatic screwing device according to one of claims 1 to 3, characterized in that the loading device (7) has a spring-loaded locking pawl (16) which projects into a guide channel (15) of the loading device (7), which is designed and mounted in such a way that the locking pawl (16) is pressed out of the guide channel (15) by a screw (2) conveyed forwards against its spring preload when the belt (8) moves forwards in the feed direction (V) and when the feed pawl (11.1, 11.2), in particular the first Conveyor pawl (11.1) and the second conveyor pawl (11.2), from the advance position into the retraction position against the advance direction (V), the locking pawl (16) projects into the guide channel (15) in order to prevent the belt (8) from moving backwards. 5. Automatic screwing device according to one of claims 1 to 4, characterized in that at least one stop pawl (13.1, 13.2) is adjustable between a holding position in which the loading screw (2a) is held in its position immediately below the screw bit (6) and a release position in which the stop pawl (13.1, 13.2) is moved out of the guide channel (15) such that the loading screw (2a) can be moved further forwards in the feed direction (V) from its position immediately below the screw bit (6). 6. Automatic screwing device according to one of claims 1 to 5, characterized in that the guide (9) is replaceably attached to a base body of the loading device. 7. Automatic screwing device according to one of claims 1 to 6, characterized in that the loading device has a seat on its base body (18) (21) in which a centering bush (22) is exchangeably fastened, wherein the centering bush (22) forms a centering guide for the screw bit (6) in order to align the screw bit (6) in a coaxial alignment with respect to the loading screw (2a). 8. Automatic screwing device according to one of claims 1 to 7, characterized by a drum magazine (32) comprising: - a drum axle (33) which is designed to wind up a belt (8) on which a plurality of screws (2) are prefabricated at equal screw spacings (A) from one another and in parallel alignments to one another, - a first limiting disk (34.1) arranged at one end of the drum axis (33) and a second limiting disk (34.2) arranged at the other end of the drum axis (33), wherein at least the first limiting disk (34.1) and/or the second limiting disk (34.2) is mounted axially displaceably on the drum axis (33) for adaptation to different screw lengths and/or screw sizes. 9. Automatic screwing device according to one of claims 1 to 8, characterized in that the loading device (7) has a knife guide (23) which is designed to guide a cutting blade (24) of a cutting device (25) which is designed to automatically sever a section of belt strap which has passed through the loading device (7) and/or is empty from the belt (8). 10. Robot tool, comprising a base support (29), a tool flange (30) arranged on the base support (29) and designed to fasten the robot tool (28) to a connection flange of a robot arm, as well as having several on the base support (29) arranged mounting supports (31), which are designed for the individual fastening of an automatic screwing device (1) according to one of claims 1 to 9.