Driven screw device for multiple screw widths

Abstract

An actively driven screwing device with a, in particular electric, rotary screw drive, a first tool (1) designed as an internal screwing means, a second tool (2) designed as an external screwing means, a drive shaft (4) as the drive shaft of the rotary screw drive, a gear (5) and a screw spindle (6), wherein the first tool (1), the second tool (2) and the drive shaft (4) are arranged coaxially to one another, wherein a linear drive is provided, by means of which the first tool (1), which is arranged coaxially in or partially in the second tool (2), and the second tool (2) can be displaced coaxially relative to one another with respect to their common axial direction between a first relative position in which the first tool (1) is active, and a second relative position in which the second tool (2) is active, characterized in thatthat the screw spindle (6) is arranged parallel to the drive shaft (4) and is coupled to the drive shaft (4) via the gear (5) in order to transmit the drive torque to at least one of the screw means via the gear (5).

Description

The present invention relates to an actively driven screwing device with an, in particular electric, rotary screw drive and a method for providing a screwing means.DE 10 2007 023 807 A1 shows a screwing device in which two tool holders arranged coaxially with respect to one another are always held in a fixed position with respect to one another. The tool holders are only displaced together and without displacing their position relative to one another when either a bevel gear of the outer tool holder or a bevel gear of the inner tool holder is brought into engagement with a bevel gear of the drive.A nut is used for screwing to electrical screw systems. The nut has the same width of the wrench as the screw head to be screwed. If now a plurality of screws of different sizes are to be tightened, the tool must be changed on the screw spindle of the electric screw system.For automated applications, such as e.g. wheel screwdrivers, wheel bolts or nuts of different sizes are also used for different models. The measures required to handle the different sizes are complicated, expensive, time-consuming and also prone to errors.The solutions known hitherto are primarily intended for manual actuation. In this case, a smaller width of the key is spring-mounted in the interior of the nut. It is pressed back by the screw head, if necessary, when manually attached. The service life is very short. Likewise, the torque to be transmitted is designed more for manual assembly. Process monitoring does not take place.It is the object of the present invention to provide an improved actively driven screwing device and an improved method for providing a screwing means.This object is achieved by an actively driven screwing device according to claim 1 and a method for providing a screwing means according to claim 10.The present invention is based on the finding that with a screwing device which has an inner and an outer screwing means, it is possible to simplify a change in the screw width of the screwing device. In addition, the possibility is created that a change in the screw width can be represented less prone to errors, in particular in a process-safe manner.The approach according to the invention can be used advantageously in automatic and semi-automatic assembly and in automatic and semi-automatic assembly systems. By means of the automation, different torques can also be applied which are adapted to the screw size. Furthermore, no manual changeover is required by the automation.This results in a number of advantages. This allows a secure setting of the required key width (SW). By the controlled presetting of the key width, the screw head can be found reliably in the process. This results in easier threading onto the screw head. No counterforce is to be overcome in this case, since the spring used in known systems is made possible to fail. In addition, a long service life at high torques can be achieved.According to the invention, a change of the screw width can be carried out with only one screw system and without time-consuming tool changes. With the screwing tool according to the invention, this requirement can be fulfilled automatically and in particular monitored in a reliable manner. A rapid and in particular process-safe monitored adjustment of the width of the wrench on the screwing tool is thus made possible, for example for screws and nuts.The present invention provides an actively driven screwing device with an, in particular electric, rotary screw drive as described in claim 1, and in which a linear drive is provided by means of which an inner screw means, which is arranged coaxially in or partially in an outer screw means, and the outer screw means can be displaced coaxially relative to their common axial direction between a first relative position, in which the inner screw means is active, and a second relative position, in which the outer screw means is active.Active can mean that the respective screw means / the nut is in an engagement position. In the engagement position, a screw of the corresponding size is detected by the screw means, in particular in a process-safe manner, i.e. for example with regard to the engagement in a reproducible and measurable manner or can be verified by simple measurement, and can be screwed in or out.According to one embodiment, a drive shaft of the rotary screw drive can be displaced radially parallel with respect to the screw axis of the screw means, wherein a transmission is provided which transmits the drive torque to at least one of the screw means. This makes it easier to provide a changeover switch in or on the drive shaft, with which changeover switch can be switched between the first and the second relative position.An attachment gear can be provided as the gear.A pneumatically, hydraulically or electrically driven spindle drive can be provided as the rotary screw drive. Known spindle drives can be used here, which are already used, for example, in automatic or semi-automatic mounting systems.A pneumatic cylinder, a hollow shaft motor, an electric linear drive or an electric solenoid can be provided as the linear drive. A corresponding selection for the linear drive can be selected according to the respective requirements or circumstances.According to one embodiment, at least one sensor can be provided which can detect the first and the second relative position, in particular in a process-safe manner, and can communicate in particular to an evaluation unit, e.g. a controller, as described in claim 6. In this way, a changeover between the relative positions can be monitored and displayed.For example, a first sensor can detect the first relative position and / or a second sensor can detect the second relative position. Such an arrangement is simple to realize.Furthermore, the drive shaft can be designed substantially in the manner of a hollow shaft and an actuator of the linear drive can be led through the hollow shaft or vice versa. In this way, a simple and reliable actuation is possible.The present invention further provides a method for providing a screwing means of an actively driven screwing device having an, in particular electric, rotary screw drive, wherein the screwing device has an inner screwing means, an outer screwing means and a linear drive as described in claim 10, wherein the inner screwing means is arranged coaxially in or partially in the outer screwing means, and wherein the inner screwing means is active in a first relative position and the outer screwing means is active in a second relative position, wherein the method comprises the following steps: receiving, with at least one sensor of the screwing device, information about whether the outer screwing means or the inner screwing means is to be activated; actuating the rotary screw drive in order to displace the inner screw means and the outer screw means coaxially relative to one another with respect to their common axial direction, so that the inner screw means and the outer screw means assume either the first relative position or the second relative position depending on the information.According to the invention, several steps required can be done in one. No continuous tool change is necessary and a secure finding of the screw head is ensured.The invention is explained in more detail below by way of example with reference to the attached drawings. The following are shown: FIG. 1 shows a schematic representation of a screw device according to an embodiment of the invention; and FIG. 2 shows a flow diagram of a method according to an exemplary embodiment of the invention.Identical or similar elements can be provided with identical or similar reference numerals in the following figures. Furthermore, the figures of the drawings, their description and the claims contain numerous features in combination. A person skilled in the art will understand that these features can also be considered individually or they can be combined to form further combinations which are not explicitly described here.FIG. 1 shows a schematic illustration of a screw device according to an exemplary embodiment of the present invention. This can be an actively driven screw device with a rotary screw drive.According to this exemplary embodiment, the screwing device has a tool 1 and a tool 2 that can be adjusted. The tool 1 is designed as an inner screwing means and the tool 2 which can be adjusted is designed as an outer screwing means. In this case, the tool 2 that can be adjusted is integrated in the tool 1 in such a way that it is completely or partially surrounded by the tool 1. The screwing device further comprises an actuator 3, a drive shaft 4, a gear in the form of an attachment gear 5 and a screw spindle 6. The tool 1, the feedable tool 2 and the drive shaft 4 are arranged coaxially with respect to one another. The tool 1 may be fixedly or interchangeably attached to one end of the drive shaft 4.The actuator 3 can be arranged within the drive shaft 4 and can be operated from an end of the drive shaft 4 opposite the tool 1. The actuator 3 can be designed to move the tool 2 that can be adjusted back and forth between a first relative position and a second relative position. In order to assume the first relative position, the tool 2 that can be adjusted can be moved away from the drive shaft 4. In the first relative position, a nut to be screwed or a screw head to be screwed can be introduced into the tool 2 that can be adjusted. In order to make this possible, a first end of the feedable tool opposite the drive shaft 4 can, in the first relative position, end with a corresponding first end of the tool 1 or protrude beyond it. Alternatively, the first end of the feedable tool 2 can still be located within the tool 1 in the first relative position, wherein it is ensured that the nut or the screw head to be received by the feedable tool 2 can be inserted sufficiently far into the feedable tool 2 in order to reliably transmit the required torque. In the second relative position, a nut or a screwing head to be screwed can be inserted sufficiently far into the tool 1 in order to reliably transmit the required torque. In order to assume the second relative position, the tool 2 that can be adjusted can be moved within the tool 1 in the direction of the drive shaft 4. For example, an end of the feedable tool 2 facing the drive shaft 4 can, in the second relative position, bear against the drive shaft 4 or against an end of the tool 1 facing the drive shaft 4 or a gap can be removed therefrom.The tool 1 and the tool 2 that can be adjusted can each be designed as a nut and each have an opening at the end opposite the drive shaft 4. A screw head or a nut can be inserted into the opening. The tool 2 that can be advanced has an outer diameter that is smaller than an inner diameter of the tool 1. Thus, there may be a gap between the tool 1 and the feedable tool 2, which gap may be large enough to be able to move the feedable tool 2 back and forth in the tool 1 and which gap may be small enough to allow torque transmission between the tool 1 and the feedable tool 2.The screw spindle 6 can be arranged parallel to the drive shaft 4 and coupled to the latter via the auxiliary transmission 5. Thus, a torque of the screw spindle 6 can be transmitted via the attachment gear 5 to the drive shaft 4 and to the tool 1 and, if applicable, to the tool 2 that can be adjusted.The screwing device shown in FIG. 1 can furthermore have a first sensor 7 and a second sensor 8 and a changeover switch 9. The changeover switch 9 can be arranged at an end of the drive shaft 4 opposite the tool 1. The actuator 3 can be operated accordingly by the changeover switch 9 in order to move the tool 2 which can be advanced back and forth between the relative positions. A corresponding position of the feedable tool 2 can be detected by means of the sensors 7, 8. For this purpose, the sensors 7 and 8 can be designed, for example, to detect a position of the actuator 3 or of the changeover switch 9. For example, the first sensor 7 can be designed to detect the first relative position and the second sensor 8 can be designed to detect the second relative position. The sensors 7, 8 can have an interface in order to provide information about the detected relative position. Furthermore, the changeover switch 9 can have an interface via which an instruction for switching between the relative positions can be received.The screwing device according to the invention can be suitable for automated applications. For example, the screwing device can be used as a wheel wrench in the vehicle sector. With such a wheel wrench, wheel screws or wheel nuts can be screwed or loosened. Different vehicle models can have wheel bolts or wheel nuts of different sizes. These can be handled using one and the same wheel wrench on account of the tool 1 and the integrated feedable tool 2, without a tool change being required. Thus, at least two different key widths can be provided by the screwing device, between which the device can be switched. The screwing device according to the invention can, however, also be provided for any other desired application areas in which, for example, an alternating provision of different tool sizes is required.According to this exemplary embodiment, the screw spindle 6 has an attachment gear 5 instead of a straight output. The attachment gear 5 has a screw output provided with a through bore. Mounted on this screw drive is a tool 1 designed as a nut, which has the greatest required width of the wrench. In the cavity of the tool 1 there is mounted a feedable tool 2, e.g. a hexagonal element, torx, or double hexagonal 2, or a crown or a "surface drive" nut, which has the diameter for the smaller width of the key. This feedable tool 2 preferably only has the task of positively receiving the screw head and, when tightened, of conducting the counterforce generated by the screw head further to the outer walls of the tool 1 designed as a nut.The actuator 3 can be designed as an actuator shaft and can be designed to selectively push the insert 2 forward or backward. The respective position can be monitored by the sensors 7, 8.The screw axis is radially and coaxially displaced with respect to the spindle axis by the attachment gear 5, so that there is geometric installation space for the arrangement of a direct linear drive for the linear displacement of one of the two tools 1, 2. In this case, the tool 2 that can be adjusted is preferably displaced.The torque is applied by the screw driver via the tool 1 to the positively adjustable tool 2.As a result of the counter-torque arising in the final tightening phase, the tool 2 which can be adjusted is supported on the tool 1 as it were.The linear drive for displacing the feedable tool 2 is rotatably mounted, since the drive shaft 4 of the screwdriver is likewise intended to rotate or must rotate. Because the two tools 1, 2 are arranged coaxially, in particular on one and the same axis, the tool change is reliable. The two sensors 7, 8 also contribute to the process safety. The sensors 7, 8 can also be omitted if necessary.The linear displacement can be realized, for example, by means of pneumatic cylinders or solenoids or by means of other linear drives. A solenoid would be used, for example, if there is no compressed air at the plant.The drive shaft 4 can be a hollow shaft and the screw axis of the actuator 3 can be arranged coaxially in the center thereof.In FIG. 1, reference numeral 1 denotes the larger hexagon, and reference numeral 2 denotes the smaller hexagon. Instead of a hexagon, all other screwing tool shapes, for example a crown, torx, double hexagon, or other special shapes can also be used.Such crowns can be inserted and an insert in the form of a crown can be slid into the arches of the outer crown to make the change to the smaller width of the key.In the exemplary embodiment shown, when using the tool 1 in the form of the larger nut (e.g. M 19), the feedable tool 2 in the form of the smaller nut (e.g. M 17) is intended to be retracted to such an extent that the tool 1 can completely axially receive a screw in its entire hexagonal height without hindrance by the feedable tool 2. For this purpose, the tool 1 in the form of the nut is designed to be correspondingly deep. The variables M 17, M 19 are specified here only by way of example. In particular, the sizes can be interchangeable. For example, the tool 1 and the tool 2 that can be adjusted can be inserted into each other and placed on the actuator 3 and the drive shaft 4 and can be removed from them.The actuator 3 and the drive shaft 4 are rotationally rigid, for example positively locking, but axially displaceable relative to one another. For example, the actuator 3 can have interlocking elements with the drive shaft 4 along part of its length or its entire length, e.g. a hexagonal shape.The drive shaft 4 can also be designed as a simple, round shaft which can bear only on the receiving side of the tool, for example a thread for fastening the inner tool 2. The entrainment will then take place in particular already solely by the form fit of the tool.FIG. 2 shows a flow diagram of a method for providing a screw means of an actively driven screw device, according to an exemplary embodiment of the present invention. The screw device can be, for example, the screw device described with reference to FIG. 1.In a first step 21, an item of information can be received about whether the outer screw means or the inner screw means is to be provided and thus activated. The information can be provided, for example, as an electrical signal via an interface to the screw device. In response to the information, in a second step 22, the rotary screw drive can be actuated. By means of the rotary screw drive, the inner screw means and the outer screw means can be displaced coaxially relative to one another with respect to their common axial direction. If the information indicates that the inner screw means is to be activated, the actuation of the rotary screw drive can be effected such that the inner screw means and the outer screw means are moved relative to one another into the first relative position. If the information indicates that the outer screw means is to be activated, the actuation of the rotary screw drive can be effected such that the inner screw means and the outer screw means are moved relative to one another into the second relative position. The steps described can be repeated as desired according to the tools required.The exemplary embodiments shown are chosen only by way of example and can be combined with one another. The claims are only suggest formulations without any limiting effect on the disclosure content. Combinations of features from the description in each combination - in particular also without the claims - are also encompassed by the disclosure. The claim hierarchy also does not restrict the disclosure, so that each sub-claim can also define an independent scope of disclosure and be claimed independently or in combination with other features from the claims and / or the description.List of reference characters1 Tool 2 Tool 3 Actuator 4 Drive shaft 5 Attachment gear 6 Screw spindle 7 First sensor 8 Second sensor 9 Changeover switch

Claims

Actively driven screwing device having an, in particular electric, rotary screw drive, a first tool (1) which is designed as an inner screw means, a second tool (2) which is designed as an outer screw means, a drive shaft (4) as a drive shaft of the rotary screw drive, a transmission (5) and a screw spindle (6), wherein the first tool (1), the second tool (2) and the drive shaft (4) are arranged coaxially with respect to one another, wherein a linear drive is provided by means of which the first tool (1), which is arranged coaxially in or partially in the second tool (2), and the second tool (2) can be displaced coaxially with respect to one another with respect to their common axial direction between a first relative position in which the first tool (1) is active and a second relative position in which the second tool (2) is active, characterized in that, the screw spindle (6) is arranged parallel to the drive shaft (4) and is coupled to the drive shaft (4) via the transmission (5) in order to transmit the drive torque to at least one of the screw means with the transmission (5).Screwing device according to claim 1, characterised in that the drive shaft of the rotary screw drive is displaced radially parallel with respect to a screw axis of the screwing means.Screwing device according to claim 2, characterised in that an attachment gear is provided as the gear (5).Screwing device according to one of Claims 1 to 3, characterized in that a pneumatically, hydraulically or electrically driven spindle drive is provided as the rotary screw drive.Screwing device according to one of Claims 1 to 4, characterized in that a pneumatic cylinder, a hollow shaft motor, an electrical linear drive or an electrical solenoid is provided as the linear drive.Screwing device according to one of claims 1 to 5, characterised in that at least one sensor (7, 8) is provided for detecting the first and the second relative position, wherein the at least one sensor (7, 8) has an interface for providing information about the detected relative position.Screwing device according to claim 6, characterised in that a first sensor detects the first relative position and / or a second sensor detects the second relative position.Screwing device according to claim 5 or 6, characterized in that the screwing device comprises a changeover switch (9) having an interface for receiving an instruction for switching between the relative positions.Screwing device according to one of Claims 1 to 8, characterized in that the drive shaft (4) is designed substantially in the manner of a hollow shaft and an actuator (3) of the linear drive is led through the hollow shaft or vice versa.Method for providing a screwing means of an actively driven screwing device having an, in particular electric, rotary screw drive, wherein the screwing device has a first tool (1) which is designed as an inner screwing means, a second tool (2) which is designed as an outer screwing means, a drive shaft (4), a gear mechanism (5), a screw spindle (6), at least one sensor (7, 8) and a linear drive, wherein the first tool (1), the second tool (2) and the drive shaft (4) are arranged coaxially with respect to one another, wherein the first tool (1) is arranged coaxially in or partially in the second tool (2), wherein the first tool (1) is active in a first relative position and the second tool (2) is active in a second relative position, and wherein the screw spindle (6) is arranged parallel to the drive shaft (4), and coupled to the drive shaft (4) via the transmission (5) in order to transmit the drive torque to at least one of the screwing means with the transmission (5), wherein the method comprises the following steps: receiving, with the at least one sensor (7, 8), information about whether the second tool (2) or the first tool (1) is to be activated; actuating the rotary screw drive in order to displace the first tool (1) and the second tool (2) coaxially relative to one another with respect to their common axial direction, such that the first tool (1) and the second tool (2) assume either the first relative position or the second relative position depending on the information.

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