Screwing tool head, screwing tool, method for screwing in a screw using the screwing tool, and computer program product

Abstract

The invention relates to a screwing tool head (100) having at least one spindle unit (101, 102) which is designed to receive a screwing means (130, 131, 132) for screwing in a screw (1) or similar screw element, the screwing tool head (100) being designed for installation in a screwing tool (1000), in particular an automatic screwing machine, and the spindle unit (101, 102) comprising: - a spindle (110, 111, 112) which is arranged axially with respect to the spindle unit and has a drive side (110a) and a head side (110k), it being possible for the spindle to be coupled on the drive side to an output unit (1200) of the automatic screwing machine and to be rotated by this output unit and it being possible for the screwing means (130, 131, 132) to be received on the head side of the spindle (110, 111, 112) for attachment to a screw head (3) of the screw (1); and - a reference structure which extends at least partly along the spindle unit (101, 102), is movable axially with respect to the spindle, is held on the spindle unit (101, 102) and can be rotated relative to the spindle. According to the invention: - a measuring attachment (MA), which is designed for a distance measurement (A) between the drive side (110a) and the head side (110k), is attached to the spindle (130, 131, 132); and - a measuring device (ME), which is designed for the distance measurement (A) between the head side (110k) of the spindle and the measuring attachment (MA) and interacts with the measuring attachment, is attached to the reference structure; and - a spacer element for the reference structure is provided, the spacer element being designed to be placed on a screw base.

Description

[0001] DESCRIPTION

[0002] Screwing tool head, screwing tool, method for screwing a screw with the screwing tool and computer program product

[0003] The invention relates to a screwing tool head according to the preamble of claim 1. Such a screwing tool head has at least one spindle unit which is designed to receive a screwing means for screwing in a screw or similar screw element, wherein the screwing tool head is designed for installation in a screwing tool, in particular a screwing machine, and the spindle unit comprises:

[0004] - a spindle arranged axially of the spindle unit with a drive side and a head side, wherein the spindle is designed to be coupled on the drive side to an output unit of the screwing machine and rotatable thereover, and the screwing means for engagement with a screw head of the screw is accommodated on the spindle head side,

[0005] - a reference structure extending at least partially along the spindle unit, which is axially displaceable relative to the spindle and which is held on the spindle unit and relative to which the spindle is rotatable.

[0006] The invention also relates to a screwing tool, in particular a screwing machine or similar partially or fully automated screwing tool, with a screwing tool head of the type mentioned at the beginning, as well as a method for screwing in a screw with a screwing tool and a computer program product designed to carry out the method for screwing in a screw with a screwing tool.

[0007] Screwing tools, in particular automatic screwing machines or similar partially or fully automated screwing tools, with a screwing tool head are known per se and a general mode of operation is described, for example, in EP 0 600 285 A1.

[0008] DE 10 2011 121 923 A1 describes a distance measuring device acting in a horizontal plane for a screwing machine, wherein the screwing machine has a chassis for the horizontal plane that can be moved by means of wheels or rollers and on which at least one magazine for receiving fastening elements is arranged, of which a fastening element or the individual elements to be brought together are separated from the respective magazine stream by the lifting movement of a vertically movable screwdriver arranged on the chassis and are positioned in the screwing axis and screwed.

[0009] EP 0 798 449 A1 shows a screwing tool head mentioned above, which serves as part of an adjusting device for the relative angular adjustment of a driven camshaft of an internal combustion engine. This comprises a controlled, displaceable adjusting element that is connected to the camshaft in a rotationally fixed manner via gear teeth of a drive gear and that is assigned to a stop of the adjusting device in a machine reference position. For the precise rotational position assignment of the adjusting device to the camshaft during assembly, a signaling device indicating the retarded stop position of the adjusting element at the stop is provided in an assembly-dependent reference position of the internal combustion engine.

[0010] Such processes are used to fully or partially screw in a screw or similar screw elements of the aforementioned type, usually using stationary screwing tools in a production chain. Particular care is required; however, in general, with any type of automated screwing process, care must be taken to ensure that the screwing is carried out and completed according to specifications and without damaging the screw.

[0011] In the case of torque-controlled screw joints, the achieved tightening torque can be used to a certain extent to check compliance with all specifications for the screwing process; in the case of screw joints controlled by the angle of rotation—such as that in EP 0 798 449 A1—a cumulative angle of rotation is used to check a reliable screw joint.

[0012] The latter approach is particularly problematic, however, if the screwing tool's contact with the screw head is incomplete. Slipping of, for example, screw sockets on electrically driven screw spindles can then occur when tightening screws or nuts—these and other nuts are generally referred to as screw heads in the following. To prevent screw sockets from slipping, the screwing program generally attempts to encourage a so-called snap-over of the sockets via the rotating movement of the screw spindles (also known as the "threading process" or "finding stage"). There are also chamfers on screw sockets or specially shaped "surface drive" sockets designed to facilitate this.For example, DE 10 2005 014 901 A1 describes a pneumatic screwing system with a screwing device that is fastened to a holder and that contains a screwing tool that can be moved back and forth in a screwing channel between a retracted starting position and an advanced screwing position, with a screw feed device with a magazine from which a screw is fed into the screwing channel, and with a work table on which a workpiece can be fastened into which the screw can be screwed, and with a torque detection device, wherein the screwing device has a travel measuring device that detects the distance covered by the screwing tool until the end of the screwing process, wherein the screwing device has a further measuring device that detects the position of the upper edge of the workpiece.

[0013] However, these measures cannot ensure that the screwing tool engages the screw head sufficiently; monitoring and detecting an incorrect screwing process can usually no longer prevent damage to the screw head.

[0014] Despite the known measures, it occasionally still happens that - depending on the screwing application and system design - screw heads are damaged by slipping. This can occur especially in all automatic screwdriving processes with high torques. However, it can happen that the socket slips as the torque increases, leaving the screw in place. With angle tightening (a screwing specification here is not a final torque, but a final angle) - especially with high angle specifications of 180°, for example - it can also happen that the socket threads itself back on due to a slow final stage speed - for example, with hexagon screws after 60° - and thus simulates a good end result.

[0015] If this is not discovered otherwise, it can have fatal consequences for the (often demanding angle of rotation) screw connection.

[0016] Such cases could be avoided with reliable detection that the socket is correctly inserted. This is where the invention comes in, the object of which is, in a first aspect, to provide a screwing tool head and a screwing tool by means of which a sufficient engagement of the screwing means with the screw head can be ensured, in particular such that the screwing means is engaged with the screw head, preferably such that the engagement of the screwing means with the screw head is completely engaged or at least sufficiently far for the required force transmission.

[0017] In a second aspect, a method for screwing in a screw is to be specified to solve this problem.

[0018] The object is achieved according to the first aspect by a method according to claim 1.

[0019] Accordingly, the invention is based on a screwing tool head mentioned at the outset with at least one spindle unit, which is designed to receive a screwing means for screwing in a screw or similar screw element, wherein the screwing tool head is designed for installation in a screwing tool, in particular an automatic screwing machine. The spindle unit has

[0020] - a spindle arranged axially of the spindle unit with a drive side and a head side, wherein the spindle is designed to be coupled on the drive side to an output unit of the screwing machine and rotatable thereover, and the screwing means for engagement with a screw head of the screw is accommodated on the spindle head side,

[0021] - a reference structure extending at least partially along the spindle unit, which is axially displaceable relative to the spindle and which is held on the spindle unit and relative to which the spindle is rotatable.

[0022] According to the invention, it is provided that

[0023] - a measuring attachment designed for distance measurement is attached to the spindle between the drive side and the head side, and

[0024] - a measuring device is attached to the reference structure between the head side of the spindle and the measuring attachment for distance measurement and interacting with the measuring attachment.

[0025] In an alternative variant, the concept of the invention includes that (conversely) a measuring device designed for distance measurement is attached to the spindle between the drive side and the head side, and a measuring attachment designed for distance measurement between the head side of the spindle and the measuring device and cooperating with the measuring device is attached to the reference structure.

[0026] The variants can generally be combined. A distance measurement is performed by the measuring device interacting with the measuring attachment. This means that the measuring device has physical means capable of specifying a distance between the measuring device and the measuring attachment, in particular, the distance in the sense of a distance set in relation to each other between the measuring device and the measuring attachment.

[0027] According to the invention, the spindle unit further comprises:

[0028] - an additional spacer element to the reference structure or one formed with the reference structure, wherein the spacer element is designed to be placed on a screw base.

[0029] The phrase "in joint" also includes the fact that the screwing element mounted on the spindle head is in at least sufficient joint with the screw head. In particular, this means that the joint is sufficient to provide a complete force-transmitting and optimized, or optimal to maximum torque-resistant, positive connection between the screwing element and the screw head in this state of complete or partial but sufficient joint.

[0030] The screwing tool head according to the invention, with the design of the spindle unit, ensures that when the screwing means is in sufficient engagement with the screw head (i.e. preferably complete or sufficiently partial engagement so that a screwing process can be completed safely), this is recognizable or recognizable if this should not be the case.

[0031] In a first aspect, the invention also relates to a screwing tool, in particular a screwing machine or similar partially or fully automated screwing tool, with a screwing tool head according to the concept of the invention, ie of the aforementioned type, and with a screwdriver drive for driving at least one spindle of the screwing tool head.

[0032] The object is achieved according to the second aspect by a method for screwing in a screw; in the method, the invention provides for the use of the screwing tool according to the first aspect of the invention. According to the invention, the method comprises the steps

[0033] - optionally screwing in the screw up to a protrusion dimension,

[0034] - Threading the screw, if possible in such a way that when an additional spacer element is attached or formed with the reference structure, preferably in the form of a cage, the screwing means accommodated on the head side of the spindle is positioned on the screw head in such a way that it is in contact with the screw head,

[0035] - Check whether the screwing tool is in contact with the screw head, using the measuring device attached to the reference structure designed for distance measurement and cooperating with the measuring attachment attached to the spindle, OR

[0036] - Check whether the screwing device is in contact with the screw head by means of the measuring attachment attached to the reference structure, which is designed for distance measurement and interacts with the measuring device attached to the spindle

[0037] - Screw in the screw with the screwing tool.

[0038] It is advantageous to screw in the screw only when the distance measurement confirms that the screwing means mounted on the head side of the spindle is in contact with the screw head.

[0039] According to the second aspect, the object also leads to a computer program product designed to carry out the method for screwing in a screw with a screwing tool according to the invention when the computer program product is executed on the screwing tool.

[0040] Put simply, the invention conceptually offers an improved measurement system by which the relative height of the screw spindle, or for example, the screw socket, to the screwed component can be measured. The measurement system of the invention—with the design as claimed—also avoids uncertainties regarding variances and changes in the screwing element and the screw head in an improved manner.

[0041] The invention thus conceptually offers an improved measurement system. For this purpose, a measuring attachment is mounted on the spindle between the drive side and the head side for distance measurement, and a measuring device is mounted on the reference structure between the head side of the spindle and the measuring attachment for distance measurement and interacts with the measuring attachment. The measuring attachment and the interacting measuring device can also be arranged in reverse, i.e., the measuring attachment is mounted on the reference structure and the measuring device is mounted on the spindle.

[0042] The distance measurement therefore only uses defined reference points, namely the spindle and the reference structure, but not directly the screwing tools and screw heads, which are subject to variances; even variances in the screw base are minimized to a certain extent.

[0043] The invention proposes a means, generally referred to as a spacer element, for continuing the reference structure, which can be specially designed.

[0044] This means that the spindle unit is free of variations and is designed reliably so that when the spacer element is attached, the screwing means mounted on the head side of the spindle can be positioned on the screw head in such a way that it is in contact with the screw head, whereby the distance measurement shows that the screwing means is in contact with the screw head.

[0045] Advantageous further developments of the invention can be found in the dependent claims and specify in detail advantageous possibilities for realizing the concept explained above within the scope of the task and with regard to further advantages.

[0046] The spindle unit is advantageously designed in such a way that when the spacer element is attached, the screwing means accommodated on the head side of the spindle can be positioned on the screw head in such a way that it is in contact with the screw head.

[0047] It is advantageous that the distance measurement makes it possible to determine whether the screwing means is in contact with the screw head.

[0048] The spacer element for the reference structure can preferably be held on and / or with a stop to the reference structure and by the reference structure. The spacer element is preferably designed to surround the head side and the screw means, wherein the spacer element is further designed for placement on a screw base. The spacer element can thus be understood as the distal end of the reference structure and, in an advantageous further development, can also be formed, for example, integrally with the reference structure; in this respect, a further development of the invention fundamentally encompasses a wide variety of possibilities for designing the spacer element on and / or with a stop to the reference structure and held by the reference structure.

[0049] It is advantageous that

[0050] - the spacer element is provided and / or designed as a distance-maintaining element between the screw base and the reference structure, and / or

[0051] - the spacer element is held on and / or with a stop to the reference structure and by the reference structure.

[0052] Advantageously, the spacer element comprises one or more of the elements selected from the group of elements arranged individually or in pairs, consisting of: a plate, a finger, a pin, a tube, a cage, in particular wherein the tube and / or the cage is designed to surround the head side and the screw means.

[0053] It is advantageously provided that the reference structure is formed as a sleeve which extends off-axis of the spindle unit and surrounds the spindle, which sleeve extends off-axis of the spindle unit and surrounds the spindle, in particular wherein the spacer element in the form of a tube and / or the cage is aligned with the sleeve and is designed to surround the head side and the screw means.

[0054] Advantageously, the spacer element placed on a screw base is designed with a stop to the reference structure for displacing the reference structure axially and relative to the spindle, wherein a relative displacement path between the reference structure and the spindle is detected by the measuring device cooperating with the measuring attachment.

[0055] The additional spacer element or the spacer element formed with the reference structure is particularly advantageous, but not necessarily, in the form of a cage. The reference structure is particularly advantageous, but not necessarily, in the form of a sleeve, advantageously as a sleeve extending off-axis from the spindle unit and surrounding the spindle. The spacer element and the reference structure can also merge into one another in one piece or be formed integrally as a single part.

[0056] The spindle unit has particularly advantageous features according to the above-mentioned:

[0057] - a cage for the sleeve extending off-axis from the spindle unit and surrounding the spindle, wherein the cage is designed to be placed on a screw base. Advantageously, the cage can simply represent a section of the sleeve.

[0058] It is advantageously provided that - analogous to the spacer element and the reference structure - the attached cage (or generally a spacer element) is designed with a stop to the sleeve (or generally to the reference structure) and is held by the sleeve for displacing the sleeve axially and relative to the spindle, wherein a relative displacement path between the sleeve and the spindle is detected by the measuring device cooperating with the measuring attachment.

[0059] Advantageously, it is provided that the distance measurement is designed to indicate a distance dimension, in particular by means of a relative displacement path between the sleeve and the spindle, wherein the distance dimension, set in relation to a distance threshold value, indicates that the screwing means is in engagement with the screw head.

[0060] The improved measuring system of the invention is fundamentally capable of advantageously comparing a distance measurement measured by means of the distance measurement with specified target values ​​in a reliable manner, namely, above all, while avoiding the variances that otherwise existed up to now.

[0061] It is advantageous that

[0062] - the measuring attachment is designed as a measuring plate around the spindle, and / or

[0063] - the measuring device is a non-contact measuring device, in particular for detecting a measuring pulse transit time or a phase-sensitive measuring signal between the measuring attachment and the measuring device, preferably a measuring device based on a light signal, a radio signal or similar electromagnetic measuring signal or a sound measuring signal between the measuring attachment and the measuring device.

[0064] It is advantageously provided that the measuring attachment and the measuring device are arranged along a distance measuring section extending axially along the spindle unit, in particular wherein the measuring section extends along the spindle between an upper end of the sleeve and the drive side.

[0065] A further development advantageously provides for a calibration ring for the screwing tool head, which is held with a stop to the sleeve and by the sleeve, and which is designed to surround the head side and the screwing means, wherein the calibration ring is further designed to be placed on a screw base, wherein the calibration distance set by the calibration ring for displacing the sleeve axially and relative to the spindle is known in advance and can be determined.

[0066] Advantageously, the spindle and / or the sleeve are spring-mounted, in particular spring-loaded. Instead of spring-loaded mounting, the weight of the spindle and / or the reference structure, in particular a sleeve, can also be used if the weight acts in the screwing direction.

[0067] It is advantageously provided that the measuring device is designed to transmit and / or receive an evaluation and / or information signal, wherein the evaluation and / or information signal contains one or more of the default or evaluation information items selected from the group of default or evaluation information items consisting of: an offset value for a screw head of a screw, in particular a screw head with a collar, a tolerance value for a screw head of a screw, a projection value for a projection of a screw head from the screw base, a calibration distance for moving the sleeve axially and relative to the spindle, a distance threshold value that indicates that the screwing means is applied to the screw head.

[0068] In particular, it can be used because the position and height of the screw head are usually known. This also allows for the calculation of how far the socket is placed over the screw head, and thus ultimately how far the socket's output geometry engages the screw's drive geometry. If this engagement is too small, it is insufficient for smooth and non-destructive application of the screw torque.

[0069] Ideally, especially with regard to the process, in electronically controlled screwdriving systems the finding stage is automatically repeated until the overlap is sufficient. To prevent endless loops in the event of mechanical defects or similar, a fixed finding duration should be specified. If this is exceeded, a fault can be triggered. Advantageously, a measurement evaluation unit is designed to record one or more of the evaluation variables selected from the group of evaluation variables consisting of: number of confirmed and / or non-confirmed threading processes in which the screwdriving tool held on the head side of the spindle comes into contact with the screw head, in particular is in contact with the screw head, one or more threshold values ​​for the number of threading processes and / or for a time period of a threading process.

[0070] It is advantageously provided that the screwing tool head is designed as a double screwing tool head, wherein the spindle unit is formed as a first spindle unit and a second spindle unit is formed analogously to the spindle unit.

[0071] It is advantageously provided that the screwing tool head is designed as a double screwing tool head with a first and a second spindle unit, and the screwdriver drive has an output with a first output unit for driving a first spindle of the first spindle unit and with a second output unit for driving a second spindle of the second spindle unit.

[0072] It is advantageous that the screwdriver drive is designed to implement the drive of the first and second spindle by means of the output synchronized to each other and with opposite directions of rotation.

[0073] Embodiments of the invention will now be described below with reference to the drawings in comparison to the prior art, some of which are also shown. These are not necessarily intended to represent the embodiments to scale; rather, where useful for explanation, the drawings are presented in a schematic and / or slightly distorted form. With regard to supplements to the teachings immediately apparent from the drawings, reference is made to the relevant prior art. It should be noted that numerous modifications and changes to the form and detail of an embodiment can be made without deviating from the general idea of ​​the invention.The features of the invention disclosed in the description, the drawings and the claims can be used both individually and in any combination to further develop the invention; in particular, combinations of at least two of the features disclosed in the description, the drawings and / or the claims fall within the scope of the invention. The general idea of ​​the invention is not limited to the exact form or detail of the preferred embodiment shown and described below, or limited to an object that would be limited compared to the object claimed in the claims. For specified dimensioning ranges, values ​​lying within the stated limits are also intended to be disclosed as limit values ​​and to be used and claimed as desired.Further advantages, features and details of the invention will become apparent from the following description of the preferred embodiments and from the drawing, which shows:.

[0074] FIG. 1A shows an exemplary representation of screws with a damaged screw head as a result of the failure of a screwing process due to a lack of sufficiently joined screwing means of a screwdriver socket on the screw head;

[0075] FIG. 1B shows an exemplary screw curve as a screw force or torque curve over angle of rotation with an event leading to damage to a screw head due to a screwdriver socket slipping off and being re-threaded on the screw head;

[0076] FIG. 2 shows a basic schematic diagram relating to the situation on a screwing tool, such as an automatic screwing machine, with a check of the positioning of a screwing means on the screw head carried out by means of a distance measurement, the alternative shown here being particularly advantageous for a simple, advantageously hand-held, screwing tool;

[0077] FIG. 3 is a schematic representation of the situation on an advantageously stationary screwing tool, such as in an automatic screwing machine or similar screwing tool according to a particularly preferred embodiment of a screwing tool head, by means of which, in an alternative to the aforementioned FIG.

[0078] 2 even more advantageous distance measurement makes it possible to see whether the screwing means is in contact with the screw head;

[0079] FIG. 4 shows a detailed illustration of a screwing tool head according to a second preferred embodiment for installation in an automatic screwing machine or similar screwing tool; FIG. 5 shows a perspective view from below of the screwing tool head, showing its sleeve and screwdriver socket as screwing means on a spindle;

[0080] FIG. 6 is a side perspective view of the screwing tool head of FIGS. 4 and 5 according to the particularly preferred embodiment;

[0081] FIG. 7 is a side perspective view of a detail of the sleeve and the screwdriver socket and the spindle at the screw base for the embodiment of FIG. 6;

[0082] FIG. 8 is a flowchart of a basic sequence of a method for screwing in a screw with a screwing tool according to the concept of the invention, namely in particular according to an embodiment as shown in FIG. 3 to FIG. 7.

[0083] The joining of a screwdriver socket onto a screw head 3 of a screw 1 shown in FIG. 1A is typically carried out by means of a so-called threading process at the beginning of screwing the screw 1 with its thread 5 into a screw hole. Depending on the nature of the screw head 3 and the matching screwdriver socket, as well as a number of other factors, it may happen that the screw is not fully joined onto the screw head 3.

[0084] Factors include, for example, axial alignment of the spindle and screw axis; alignment of the screwing point (vertical / angled / horizontal); play between the spindle output and the nut; wear on the square end of the nut or spindle output, wear and / or contamination on the nut output; tolerances in all of the above; in particular: any combination of the factors mentioned above.

[0085] As recognized by the invention, however, the most significant of these factors are overcome, and the screwing tool head according to the concept of the invention thus supports a reliable screwing process, in which it is reliably ensured in advance, in a manner that is advantageous compared to previously known measures, that a screwing means (such as the screw) is in contact with a screw head. This is, in any case, an important and even necessary prerequisite that should be met before the start of a screwing process in order to subsequently be able to complete the screwing process of the screw with a screwing tool efficiently and without interruption, i.e., above all, successfully and without damaging the screw.In the best case scenario, it may be sufficient to abort the screwing process—even if the screwing tool, such as the screw used here as an example, is positioned against the screw head but is not or only partially in contact with it—to leave the screw undamaged. However, it is unlikely that the screwing process can be completed until the screw is fully tightened—that is, until the screw is fully installed—or that the screw remains undamaged.

[0086] The screws 1 shown as examples in FIG. 1A are the result of a less favorable case, in which the screw head 3 is damaged during the screwing process, specifically during the screwing-in process. Visible on the screw head 3 are crushed areas, dents, or similar damage 3a, 3b, 3c.

[0087] These damages 3a, 3b, 3c may make it impossible to reattach the screwing device such as the screw if the screwing process is interrupted, so that further assembly of the screw, or in any case loosening of the screw, is made difficult or even impossible.

[0088] If the screwdriver socket or similar screwing device fails or if the screw head 3 fails as a result of damage 3a, 3b, 3c, this can lead to a disruption of the entire production process and even to a plant shutdown.

[0089] The consequence is usually that a corresponding screw 1 on the object to be screwed together—such as an engine or a complex drive unit such as a generator, a genset, a fuel cell, or other parts of a drive or internal combustion engine—must be interrupted, and the last screw(s) tightened, or all previous screws and screwing operations, must be inspected or replaced. For this reason, it is also desirable to have an increased level of safety regarding the above-mentioned problem before a screwing operation.

[0090] FIG. 1B shows an example of a screw curve 2 recorded in an automatic screw machine and during monitoring of the screwing process when screwing in a screw 1. The screw curve 2 is shown as a function of torque M on the screwing tool and angle αp as the angle of rotation of the screwing means, such as the screw nut. It can be seen that the characteristic curve of the torque M over the angle of rotation αp - that is, the curve of the screw curve 2 - has a torque M during the screwing process that increases with the angle of rotation αp. The fact that, contrary to the characteristic curve, the torque drops abruptly at a rotation angle of approximately 58° in this case is the result of the screwdriver socket slipping off the screw head 3 at that point. However, the screwdriver socket threads itself back in at a rotation angle αp of approximately 60° onto the thread shown here in FIG.1 A visible hexagon screw head 3 to complete the screw tightening; deviating from the characteristic curve, the torque increases abruptly at the rotation angle cp of 60° and then follows the characteristic curve of a largely linear increase.

[0091] However, many screwdriving processes are less focused on tightening torque in the sense of torque-controlled screwdriving, but are designed more simply and thus more efficiently controlled by the angle of rotation. This means that the screwdriving process would be considered complete when the socket has traveled a certain angle of rotation—in this case of a screwing curve shown in FIG. 1B, the slipping of the socket could have gone unnoticed, and the screw could not have been fully tightened to the required angle and / or could have been damaged.

[0092] This should also be avoided as much as possible, although it is problematic if a faulty screwing process has already been detected - because even if the screwing curve 2 clearly shows a faulty screwing process, the production process is already delayed or necessarily stopped.

[0093] FIG. 2 shows in principle a view of a screwing tool 10 in relation to an object 20, into whose screw base 21 a screw 1 with screw head 3 is to be screwed.

[0094] The screwing tool 10 can advantageously be a stationary screwing machine or a hand-held screwing tool.

[0095] The screwing tool 10 has a screwing tool head 12 and a screwdriver drive 14. The screwdriver drive 14 serves to drive a spindle 11 of the screwing tool head 12, wherein a screwing means 13, such as the aforementioned screw driver, can be attached to the head of the spindle 11. The screw driver 13 receives the screw head 3 of the screw 1 and screws it in by means of the screwdriver drive 14, to which the spindle 11 is coupled via an output 16.

[0096] In principle, at and / or before the start of the actual screwing process, a statement can be made as to whether the screw nut 13 is in contact with the screw head 3 by measuring the distance A between the screw nut 13 or similar screwing means and the screw base 21, provided the basic height of a screw head 3 is known.

[0097] This already applies to a hand-held screwing tool, such as the Screw Tool 10. For hand-held screwing tools such as hand screwdrivers with a counterholder, there is not only a quality aspect, but also a safety aspect, as slipping can potentially lead to uncontrolled movements, which can cause injury or damage.

[0098] Because handheld screwdrivers usually do not have a spring-loaded spindle, but rather fixed nuts, a suitable measurement is already possible if a constant distance to the component is checked.

[0099] For the sake of simplicity, handheld screwdrivers could therefore measure directly on the component using a laser probe or similar non-contact measuring device. This also improves accessibility of the measuring system at the screw location. For a handheld screwdriver, it is therefore helpful to overcome the above-mentioned problem if the distance Al to the screw base 21 is already known.

[0100] The screw (with screw head 3) can be screwed in using the conventional screwdriving tool. Before applying increased torque, checking the distance dimension Al has proven advantageous.

[0101] Zeroing could therefore be performed directly on the component, for example, using a button on the screwdriver or sensor housing. Zeroing should be performed after each socket change.

[0102] The accuracy of the measurement could be slightly reduced compared to stationary systems and possibly also influenced by reflection from the component surface. However, due to the handheld screwdrivers, this would be acceptable or correctable in a rather shaky situation (e.g., screwdrivers are often naturally held somewhat crooked). This would open up simple command and implementation options for resolving the problem. For example, zeroing could be performed with a longer button press and, if necessary, a second confirmation press. A measured average value could also be taken – this could reduce measurement errors caused by holding the screwdriver at an angle, etc.

[0103] For handheld screwdriving tools, such as electronic torque wrenches in particular, it would be possible to warn, in particular acoustically, when a torque is built up, but the examination of the distance dimension Al shows that the screw is not sufficiently tightened.

[0104] It could also be advantageous to measure a corresponding relative measurement of a distance measurement A1 to the screw base 21 and a distance measurement A2 to the upper edge of the screw socket 13. This can provide an even more accurate statement, from which it can be seen that the screw socket 13 is in contact with the screw head 3. This distance measurement A can also be performed, for example, using a laser measurement.

[0105] In principle, the absolute height of the screw spindles must also be checked or known before the actual screwing process begins. This can be done advantageously with a discriminatory accuracy of + / -0.5 mm, which can be adjusted, for example, in a parameter window.

[0106] In this approach, which is advantageous in the concept for a screwing-in process, the joining of the screw head 3 and the screwing means such as the screwdriver socket 13 must be checked before the start of the actual screwing process.

[0107] However, as explained and although correctable, the problem is that the distance measurement Al is carried out relative to the screw base 21 and, above all, the socket 13. There are many potential sources of error here. Regarding the distance measurement Al before the screwing process, this can still be improved, especially with regard to the design of a stationary screwing tool or the screwing tool head.

[0108] The spindle height can, in principle, also be measured directly on the screw, as explained above. This should, however, primarily be done if the resulting uncertainties (e.g., due to wobbling in the square play, possibly requiring special nuts, etc.) can be sufficiently controlled. In order to be able to evaluate the nut joint, in the alternative shown in FIG. 2, in addition to the measured spindle height, the distance from the screwdriver to the motor housing must also be measured and calculated as an example of the screw base 21. The nut joint value is determined in the same way, but is not identical to the immersion depth in other variants where a nut joint check is also required.

[0109] FIG. 3 therefore shows a preferred embodiment of a screwing tool head 100 that is improved compared to the prior art and is installed in a screwing tool 1000; in particular, a stationary screwing tool, although (where applicable) application in a hand-held screwing tool is also fundamentally possible.

[0110] A more reliable way to measure is to use a precise, tilt- and shift-proof measuring plate or similar device with a measuring attachment designed for distance measurement. This should be positioned directly above the spindle's output square, as shown below. In principle, a measuring attachment designed for distance measurement can be mounted on the spindle between the drive side and the head side.

[0111] The screwing tool 1000 is shown here in the form of an automatic screwing machine, which is preferably used for automatically screwing a large number of screws on a complex object such as, for example, an engine of an internal combustion engine.

[0112] The automatic screwdriving machine shown here has a screwdriver drive 1100, which drives at least one spindle of the screwdriving tool head via an output 1200. The screwdriving tool head, designed here as a double screwdriving tool head 100, has a first and a second spindle unit 101, 102, with a first output unit 1201 being designed to drive a first spindle of the first spindle unit 101 and a second output unit 1202 being designed to drive a second spindle of the second spindle unit 102.

[0113] In principle, the screwing tool head 100 can also be designed as a single screwing tool head—similar to that shown in FIG. 2—, ie with only a single spindle unit.

[0114] However, as in the embodiment of a double screwing tool head shown here as an example and not intended to be limiting, it has proven advantageous for the screwdriver drive 1100 to be designed using the output shown here in the diagram. This means that in the present case, a first and second output 1201, 1202 and a first and second spindle 110, 120 of the first and second spindle unit 101, 102 are provided; the drive can and should be implemented in a synchronized manner. This leads to a more even load on the structure and thus also to greater dimensional accuracy during the screwing process. The screwing tool 1000 shown here as an automatic screwing machine with a double screwing tool head 100 can, however, also be designed separately and on its own, for example, with a single screwing tool head, such as the spindle unit 101 or the spindle unit 102.In another variant not shown here, the screwing tool can also be designed as a multi-spindle machine with more than two tool heads, e.g. as a three- or four-spindle machine.

[0115] For the sake of simplicity and clarity, the same reference numerals are used below for identical or similar parts or parts with identical or similar functions of a first and / or second spindle unit 101, 102.

[0116] The spindle unit 101, 102 of the screwing tool head 100 is used to screw a screw 1, recognizable by its screw head 3, into an object 20, such as an internal combustion engine. Such automatic screwing machines, as shown in FIG. 3, are used as a preferred embodiment of a screwing tool 1000 for screwing screws into a connecting rod or cylinder head, cylinder cover, or engine housing. Such screws are safety-relevant, and the screwing tool is therefore subject to a special guarantee of a safe screwing process for screwing in the screw 1 with the screwing tool 1000.

[0117] As explained in FIGS. 1 to 2, such processes are carried out as torque-controlled screwing, but above all as angle-controlled screwing processes. The automatic screwing machine can preferably be designed as a semi-automatic or even a fully automatic machine; it has a unit (not shown in detail here) for sensory detection of the screwing process itself and, if necessary, for displaying one or more monitoring parameters for the screwing process, such as the screwing curve as shown by way of example in FIG. 1B.

[0118] The screwing tool head 1000 accordingly has a spindle unit 101, 102, each having an axially arranged spindle 110, 120—i.e., on an axis a of the spindle unit 101, 102—with a drive side 110a and a head side 110k. On the drive side, the spindle 110 can be coupled to the drive unit 1200 of the automatic screwing device 1000 and is rotatable thereover. Attached to the head side of the spindle 110 is a previously explained screwing means 130, similar to the previously explained screwdriver socket. The screwing means 130 serves to engage a screw head 3 of the screw 1 and is thus to be brought into engagement with the screw head 3 for gripping and screwing the screw in.

[0119] On the left side of the embodiment of FIG. 3 concerning the spindle unit 101, the screwing means 130 is in engagement with the screw head 3. On the right side of the spindle unit 102, the screwing means 130 is attached to the screw head 3, but not in engagement; this is a condition that either exists before the screwing process or is highly undesirable during a screwing process.

[0120] If the screwing means 130 is applied to the screw head 3 but is not in contact with it, it can lead to the aforementioned problems at the start of the screwing process, i.e. damage to the screw head 3 and the further screwing process with all the associated production interruptions and safety concerns.

[0121] Therefore, a distance measurement A, in particular a distance measurement A improved from the aforementioned distance measurement A1, is provided here, which is described below for a spindle unit 101, 102. The concept of the invention is based, on the one hand, on making a distance measurement A1, as explained with reference to FIG. 2, available in principle, by means of which, when carried out on the screwing tool head 12, the preferably automated screwing tool is able to determine, via an automated test step before the actual screwing process, whether the screwing means 130 is in contact with the screw head 3.

[0122] The concept of the invention takes into account—as explained and evident from the diagram in FIG. 3—that a distance measurement A is as independent as possible of the type of screwing device being used. This means that in this case, it is irrelevant which screw 130 is used.

[0123] The particularly preferred embodiment of a screwing tool head 100 provided in FIG. 3 according to the concept of the invention for the screwing tool 1000 therefore initially provides, in a spindle unit 101, 102, the already explained spindle 110, 120 arranged axially along an axis a of the spindle unit with a drive side 110a and a head side 110k. The spindle 110 shown in FIG. 3 is coupled on the drive side to the drive unit 1200 of the screwing tool and can be turned or rotated by means of the drive unit.

[0124] By means of the rotational or multiple rotation of the spindle 110 and the screw means 130 available on the head side of the spindle 110, in this case in the form of the screw nut, the latter is thus able - in the approach to the screw head 3 of the screw 1 - to rotate the screw 1 and then screw it into the screw hole in the base screw bearing of the object 20.

[0125] The spindle unit 101, 102 has a previously mentioned independent distance measurement A with the said advantage, ie a distance measurement A independent of the type of screw means 130 currently used and a suitable arrangement of measuring attachment and measuring device cooperating with the measuring attachment for carrying out the distance measurement A.

[0126] On the spindle 130, 131, 132, a measuring attachment MA is attached between the drive side 110a and the head side 110k for a distance measurement A, and on the reference structure - in this case a sleeve 121, 122 surrounding the spindle - a measuring device ME is attached between the head side 110k of the spindle and the measuring attachment MA for the distance measurement A and interacting with the measuring attachment.

[0127] In this case, the measuring attachment MA is firmly connected to the spindle 110 and thus indicates a height position of the spindle 110; in principle, a measuring attachment MA can also be connected or coupled to the spindle 130, 131, 132 in a different way.

[0128] In the present case, the measuring device ME is firmly connected to the sleeve and thus indicates a height position of the sleeve 121, 122; in principle, a measuring device ME can also be connected or coupled to the sleeve in a different way.

[0129] The arrangement shown in the embodiment of FIG. 3 could, in principle, also be reversed, such that the measuring attachment is arranged on the sleeve and the measuring device is arranged on the spindle; and this is thus arranged "fixedly" to indicate a height position. This means that in one variant - not shown here - it can be provided that a measuring device ME designed for distance measurement A is attached to the spindle 130, 131, 132 between the drive side 110a and the head side 110k, and a measuring attachment MA designed for distance measurement A between the head side 110k of the spindle and the measuring device ME is attached to the reference structure and interacts with the measuring device ME.

[0130] In any case, a distance measurement A is performed by the measuring device ME (in this case, arranged on the sleeve and firmly connected to it for height indication) interacting with the measuring attachment MA (in this case, arranged on the spindle and firmly connected to it for indicating a height position). This means that the measuring device ME has physical means capable of indicating a distance in the sense of a distance d between the measuring device ME (and thus relevant for the sleeve) and the measuring attachment MA (thus relevant for the spindle).

[0131] In another variant, also not shown here, a distance can also be defined as a distance between the measuring device and the measuring attachment, set in relation to each other. In principle, an approach would also be conceivable in which measurements are taken directly from the spindle 130, 131, 132 as well as from the sleeve 21, 122, with a sensor pointing directly downwards in each case, e.g., onto the component to be screwed together. This would then require two sensors, i.e., two measuring devices ME.

[0132] With direct measurement, one could also measure the component directly with a sensor, but then the spindle must not deflect when placed on the component; this approach therefore has certain limitations. The spindle would have to protrude rigidly from the screw driver. In the variant shown here, the sleeve offers the advantage of capturing the deflection when calculating the difference between the "sleeve-component" and "spindle-component."

[0133] In the present case, for example, on the left side, i.e., the spindle unit 101, it can be seen that a distance dl between the measuring unit and the measuring attachment ME, MA is smaller than a distance d2 on the right side of FIG. 3, i.e., at the spindle unit 102. The reason is that the sleeve (first and second sleeve 121, 122; not shown for the sake of clarity) in both spindle units 101, 102 rests on the base screw bearing, i.e., the screw base 21. In the first spindle unit 101, the situation of the spindle is different in relation to the spindle 110 of the second spindle unit 102—i.e., specifically, at the screw means 130—i.e.a distance dl between the measuring unit and the measuring attachment ME, MA is smaller on the left than the distance d2 between the measuring unit and the measuring attachment ME, MA on the right, since the first spindle 111 of the left spindle unit 101 sits (can sit) “deeper” than the second spindle 112 of the right spindle unit 102 (since the second spindle 112 hangs further “up” on the screw means 130).

[0134] One can say that on the left side of the spindle unit 101, the screwing means 130 in the form of a screwdriver socket is in contact with the screw head 3, namely, it completely fits over and encompasses it. This means that in this fully joined state on the left side of the spindle unit 101, there is a complete force-transmitting and optimized, or optimal to maximum torque-resistant, positive connection between the screwing means 130 and the screw head 3. In contrast, the screwing means 130 in the form of a screw socket on the right side of the spindle unit 102 is attached to the screw head 3; however, the screwing means 130 in the form of a screwdriver socket clearly only encompasses the screw head 3 on the right side of the spindle unit 102 at its upper edge, or not at all.

[0135] In a subsequent, beginning rotation process, ie rotating the spindle 110 and the screwing means 130 in the form of the screwdriver nut, the following would happen:

[0136] - With the left spindle unit 101, the screwing process of screw 1 is fully implemented and completed by the right spindle 110—here the first spindle—using the screwing means 130. This is because the torque applied can be fully transmitted from the socket to the screw head 3 throughout the entire screwing process, and the screwing means 130 in the form of the socket can then be removed from the screw head 3 again. The screw head 3 remains intact and undamaged. The screwing process can be securely implemented with angle control, since the number of intended turns of the screw 1 can be carried out safely and reliably due to the screwing means 130 being fully engaged with the screw head 3.

[0137] This is by no means the case with the spindle unit 102 shown on the right. The greater distance d2 between the measuring unit and the measuring attachment ME, MA on the right—because the first spindle 111 of the left spindle unit 101 sits (can sit) "deeper" than the second spindle 112 of the right spindle unit 102 (because the second spindle 112 hangs further up on the screwing means 130) indicates this. When the screw starts to be turned using the right spindle 110—here the second spindle 112—it would slip off the screw head 3 right from the start, since it does not engage the screw head 3, or only engages it in a narrow section. In any case, a screwing process would probably have to be interrupted as the torque increases if the screwdriver socket were to slip off the screw head as a result of the increasing torque.

[0138] FIG. 4 shows in detail the structural design of a screwdriving tool 1000 in the form of an automatic screwdriving machine, specifically a semi-automatic machine in this case. For the sake of simplicity, the same reference numerals are used for identical or similar parts or parts with the same or similar function in the FIGS. 4 to 7 that refer to them below. Not shown here is the object 20, such as, for example, an engine of an internal combustion engine, as is sufficiently symbolically recognizable in FIGS. 3 and 2 and also applies in principle to FIGS. 4 to 6.

[0139] The screwing tool 1000 in this case has a screwing tool head designed as a double screwing tool head 100, which is housed in a housing frame 200, wherein the housing frame 200 is in turn held in a supporting structure 300 of the screwing tool 1000. The housing frame 200 of the screwing tool head could be supported by a supporting and stable support device 400 (actually, however, this is only necessary with a two- or multi-spindle machine if one of the two sockets breaks as an emergency protection, because otherwise the screwing device would rotate about its own axis and thus become a danger - otherwise, the other spindle serves as a counterholder or momentary support).

[0140] The housing frame 200 of the screwing tool head can be placed with this support device 400, for example, on a cylinder head surface or engine surface or a similar screw base 21 for screwing a screw 1 into a corresponding object 20, such as an engine, as explained with reference to FIG. 2 and FIG. 3.

[0141] The support structure 300 is formed here as a rod assembly 301, which is covered on the upper side by a rod assembly plate 302. The rod assembly plate 302 carries further devices to support the function of the screwing tool 1000, such as, in this case, a rotating element 303 shown, which is connected to the surroundings of the housing of the screwing tool 1000 (not shown here) in a tolerance-compensating manner. The support structure 300, with the rod assembly 301, penetrates an upper wall 201 of the particularly stable housing frame 200, which has a lower wall 203 opposite the upper wall 201 and side walls 202, 204. The housing frame 200 can thus be understood as a box-like frame structure made of solid plates for forming the walls 201, 202, 203, 204. The support structure 300 is supported on the lower wall 203 by the rod 301 passing through the upper wall 201.

[0142] Within the housing frame 200 is the screwing tool head 100, in this case forming the double screwing tool head, with a first spindle unit 101 and a second spindle unit 102. For the aforementioned reason, the spindle units 101, 102 are designed to be driven by means of the drive units 1210, 1220—arranged above the upper housing wall 201—via a corresponding first and second output 1201, 1202 below the upper supporting wall 201; in this case, these are driven synchronously with one another.

[0143] As can be seen in the lower part of FIG. 4, the spindle unit 101 is shown with a sleeve to be described in more detail, and the second spindle unit 102 is shown without that sleeve in order to provide a clearer view of the second spindle.

[0144] Having said that, each of the spindle units 101, 102 has a spindle 111, 112 arranged axially to the spindle unit 101, 102, on each of which a screwing means 131, 132 in the form of a screwdriver socket is received on the head side. Each of the spindles 111, 112 is thus individually coupled on the drive side to one of the drive units 1210, 1220 and is rotatable via the associated output unit 1201, 1202. This allows a screw to be screwed into a corresponding object using the screwing means 131, 132—that is, via the screw head located in engagement with the screwing means.

[0145] Extending outside of axis a and centered around axis a of spindle unit 101, 102 are first and second sleeves 121, 122, respectively surrounding the first and second spindles 111, 112; i.e., the first and second sleeves 121, 122 are arranged circumferentially around axis a and around the first and second spindles 111, 112, respectively. The first and second sleeves 121, 122 are each held in the respective spindle unit 101, 102 so as to be axially displaceable relative to the spindle 111, 112, which is arranged rotatably on its axis. The first and second spindles 111, 112 are each freely rotatable relative to the first and second sleeves 121, 122. In other words, the first sleeve 121 surrounds the rotatable first spindle 111 without contact, and the second sleeve 122 surrounds the rotatable second spindle 112 without contact.At the end of a sleeve, a first and second cage 141, 142 (the latter not shown) is formed as an integral part of the same or formed on it or with it, molded on or attached thereto or otherwise with a stop to the first and second sleeve 121, 122 and held by the first and second sleeve respectively.

[0146] In general, a spacer element can be provided for the reference structure, wherein the spacer element is designed to be placed on a screw base. In particular, the spacer element is provided and / or designed as an element that maintains a distance between the screw base and the reference structure, and / or the spacer element is held on and / or with a stop to the reference structure and by the reference structure. The spacer element can have one or more of the elements selected from the group of elements arranged individually or in pairs, consisting of: a plate, a finger, a pin, a tube, a cage, in particular wherein the tube and / or the cage is designed to surround the head side and the screw means.

[0147] Instead of forming the spacer element as a cage 141, 142, in a variant not shown here, the spacer element could also be designed as a half cage or finger or plate

[0148] A respective screw is arranged in the cage 141, 142 shown here or surrounded by it, that is to say in the present case the first and second screw means 131, 132 are held on the first and second spindles 111, 112, respectively.

[0149] In FIG. 5, precisely this arrangement of adjacent spindle units 101, 102 of the screwing tool head 100 is shown, each with the aforementioned first and second output units 1201, 1202, first and second spindles 111, 112, first and second sleeves 121, 122, first and second cages 141, 142, each surrounding a first and second screwing means 131, 132.

[0150] The measuring attachment can be designed as a measuring plate around the spindle, as shown here. The measuring attachment and the measuring device are clearly arranged along a distance measuring section extending axially along the spindle unit, with the measuring section extending along the spindle between an upper end of the sleeve and the drive side. Not shown here is the possibility of extending the screwing tool head with a calibration ring.

[0151] The calibration ring is advantageously, but not necessarily, held with a stop against the sleeve and by the sleeve. The calibration ring is advantageously designed to surround the head side and the screw means, with the calibration ring further configured for placement on a screw base. The calibration distance set by the calibration ring for displacing the sleeve axially and relative to the spindle is known in advance and can be determined.

[0152] The calibration ring is designed, for example, like a washer or, more generally, like a plate with a hole. In the simplest case, the washer-like calibration disc, or more generally, calibration plate, can simply be placed over / around the screw head so that the head protrudes through the hole. The spacer element, in particular the cage, then measures the upper surface of the washer-like calibration disc, or, more generally, calibration plate, instead of the underlying component surface, i.e., the screw base.

[0153] The spindle and / or the sleeve can be spring-mounted, in particular spring-loaded.

[0154] In FIG. 6, the same embodiment of the screwing tool head 100 is shown in a lateral perspective view, wherein reference is made below to the spindles 111, 112 provided with a measuring attachment MA for distance measurement A and the sleeves provided with a measuring unit ME for distance measurement A; which are thus designed to cooperate for distance measurement A.

[0155] The distance measurement A thus records a distance dl, d2 between the upper edge of the first or second sleeve 121, 122 and the respective measuring projection MA, whereby this difference can be understood as an indication of whether the aforementioned first or second cage 141, 142 is not only mounted on a screw base 21, but rather, moreover, with the cage mounted, the first or second screw means 131, 132 received on the head side of the spindle 111, 112 is in engagement with the screw head 3 of a screw 1 to be screwed in. This is clearly shown in FIG. 7 on the left side with the screw means received on the head side being mounted on the screw head and in engagement with it. The first cage 141 sits on the screw base 21 and the first screw means in the form of the screw groove 131 completely accommodates the screw head 3 over its entire circumference and its entire height - the screw head 3 is therefore not visible.

[0156] This means that the first sleeve 121, with its visible continuation of the first cage 141 shown there on the sleeve or with a stop to the sleeve and held by the sleeve, has its lowest position; it or the first cage 141 reaches the screw base 21 and rests there; the lower edge of the first cage 141 should therefore be flush with the lower edge of the screw means 131 on the screw base 21.

[0157] When using collar screws, the lower edge of the fastener does not rest on the base of the screw 21, but is slightly raised on the collar of the collar screw. This changes the nominal position of the lower edge of the fastener from "base of the screw 21" to "base of the screw 21 plus the collar height of the screw."

[0158] Since it's a measuring system, it can also be used for this purpose. In this case, simply use a different offset value.

[0159] On the right side of the screwing tool with screwing tool head 100 shown in FIG. 7, however, this is clearly not the case, since the screw must as a second screwing means 132 is indeed attached to the screw head 3 and also completely surrounds it, but is not completely in contact with it - this is recognizable because the screw must as a screwing means 132 does not rest on the screw base 21.

[0160] Thus, while a second sleeve 122 with a second cage 142 on the head side would stand on the screw base 21, the second spindle 122 would stand up at a distance from the first spindle 121 due to the screwdriver nut as the second screwing means 132 only being in contact and not in the joining.

[0161] This difference is evident from the measuring projection MA formed on the spindle between the drive side and the head side for distance measurement A, as shown in FIG. 6. In the case of the right-hand spindle unit 102—the corresponding illustration is shown schematically in FIG. 3—a distance measurement would be larger as distance d2, since the "right" measuring projection MA is raised compared to the "left" measuring projection MA in FIG. 7 or FIG. 3, so that the distance dl is smaller than the distance d2 for distance measurement A.

[0162] It can therefore be seen that the design of the first sleeve and cage 121, 141 or the second sleeve and cage 121, 142 is selected such that the regularly mounted cage 141, 142 is designed with a stop to the sleeve and held by the sleeve for displacing the sleeve axially and relative to the spindle 111, 112. A relative displacement path between the sleeve 121, 122 on the one hand and the spindle 111, 112 on the other hand is thus recorded by the measuring device ME interacting with the measuring attachment MA. The distance measurement A is accordingly designed to indicate a corresponding respective first and second distance dimension d1, d2, in particular by means of the relative displacement path between the sleeve 141, 142 and the spindle 111, 112.

[0163] The respective distance dimension can then be set relative to a distance threshold value, and this can be used to indicate whether the screwing means 131, 132 is in contact with the screw head 3. In this case, the determination can thus be made approximately such that the second distance dimension d2 is too large in the sense that it is greater than a predetermined distance threshold value (e.g., specified by dl). As a result, it can then be determined that the screw is not sufficiently in contact with the screw head 3 in the spindle unit 102 and that a screwing process should therefore not be started.

[0164] The measuring device can be designed either as a contact device (e.g., a mechanical measuring probe) or as a non-contact device. This can be used, in particular, to detect a measuring pulse propagation time or a phase-sensitive measuring signal between the measuring attachment and the measuring device, preferably a measuring device based on a light signal, a radio signal, or a similar electromagnetic measuring signal, or a sound measuring signal between the measuring attachment and the measuring device.

[0165] The measuring device can be configured to transmit and / or receive an evaluation and / or information signal. In particular, the evaluation and / or information signal can contain one or more pieces of specification or evaluation information selected from the group of specification or evaluation information consisting of: an offset value for a screw head of a screw, in particular a screw head with a collar; a tolerance value for a screw head of a screw; a projection value for a projection of a screw head from the screw base; a calibration distance for displacing the sleeve axially and relative to the spindle; and a distance threshold value indicating that the screwing means is applied to the screw head.

[0166] A measurement evaluation unit can be designed to record one or more of the evaluation variables that are selected from the group of evaluation variables consisting of: number of confirmed and / or non-confirmed threading processes in which the screwing means received on the head side of the spindle engages the screw head, in particular is in contact with the screw head, one or more threshold values ​​for the number of threading processes and / or for a time period of a threading process.

[0167] The method for screwing in the screw with a screwing tool 1000 to be carried out according to the concept of the invention within the framework of a particular embodiment thus comprises the following steps with reference to FIG. 8:

[0168] - in a first step 1001, optional, the screw 1 is screwed in until a projection dimension;

[0169] - in a second step 1003, the screw is threaded, i.e., the screwing means 130 is placed on and onto the screw head 3, i.e., the screw 1 is threaded in such a way that, with the cage in place, the screwing means 130, which is received on the head side of the spindle, is placed on the screw head 3 in such a way that it is in engagement with the screw head; this is not guaranteed at this point by the automatic mechanism of the automatic screwing machine. However, the automatic mechanism of the automatic screwing machine according to the concept of the invention is designed such that the screwing means 130, which is received on the head side of the spindle, is placed on the screw head 3 in such a way that it is in sufficient, in particular complete, engagement with the screw head;

[0170] - According to the concept of the invention, in a further step 1005, a check is carried out to determine whether the screwing means 130 is in contact with the screw head 3. This is carried out by means of the measuring device attached to the sleeve, which is designed for distance measurement and interacts with the measuring attachment attached to the spindle, as will be explained with reference to step 1005; ie, the present embodiment of the invention preferably only begins after the screw has been screwed in. The screw is screwed in using a conventional cordless screwdriver, and then the concept of the invention comes into effect.

[0171] - In a further step 1006, screw 1 is screwed in using the screwing tool 100. However, according to the concept of the invention, screwing in step 1006 only occurs if the distance measurement A confirms that the screwing means 130 received on the head side of the spindle is in contact with the screw head 3. In other words, the screwing process involving screwing in the screw in step 1006 only occurs if the distance measurement is "OK."

[0172] The screwing process is properly completed in a further step 1008 so that the next screwing process can follow.

[0173] If the measurements of spindle height and screwdriver distance show that a nut has not been completely threaded, the 'threading process' must be repeated automatically (the number of repetitions that the screwdriver automatically performs when it receives another "not OK" rating).

[0174] If, however, a distance measurement is still "not OK" even after a repetition W, an error message is generated in step 1007. In this case, the process should be intervened to correct the dividing machine or similar screwing tool 1000.

[0175] The step 1005 for checking whether the screwing means is in contact with the screw head comprises, before the distance measurement A or, if necessary, repeated W distance measurement A, the steps: zeroing N and documenting D.

[0176] In one variant, zeroing N is advantageously performed before the assembly process during system commissioning. This has the advantage that during the actual screwing process, only the distance d that occurs after the screwing device is attached needs to be measured and compared with the associated limit values. A computer program product can be configured to execute the method for screwing in a screw with a screwing tool when the computer program product is executed with a screwing tool.

[0177] The device and method for the “nut joining check”, as shown here in a preferred embodiment, can be designed so that it can be quickly and easily checked and, if necessary, reset on measuring stands.

[0178] In particular, the computer program product can be created for this purpose. This can include a human-machine interface—such as a query menu, e.g., implemented in a view or, if appropriate, in another suitable way—e.g., as a program. Suitable master parts can be created.

[0179] For insertion, the respective spindles can be lifted by springs and the master parts can be pushed underneath - a procedure can include a calibration process as follows:

[0180] - Zero measurement on the measuring stand -^Checking (zeroing if necessary) the zero value;

[0181] - Small spacer for measuring the minimum permissible height —> simulation of nuts that are almost completely but not yet fully joined;

[0182] - Large spacer for measuring the maximum permissible height —> simulation of only very minimally / barely joined nuts;

[0183] - Oversized spacer for measuring the excessive, no longer permissible height —> simulation of nuts that are only minimally or barely joined.

[0184] A spacer in the form of a calibration ring has proven advantageous. The calibration ring is shaped like a washer, for example, or more generally, like a plate with a hole. In the simplest case, the washer-like calibration disc or, more generally, calibration plate can simply be placed over / around the screw head so that the head protrudes through the hole. The spacer element, in particular the cage, then measures onto the higher surface of the washer-like calibration disc or, more generally, calibration plate instead of onto the underlying component surface, i.e., the screw base. It is actually not necessary for it to be "held by the sleeve." It is sufficient if the washer-like calibration discs can simply be placed over / around the screw head so that the head protrudes through the hole.The cage / distance / finger then measures on the higher surface of the calibration plate instead of on the underlying component surface / screw base.

[0185] Another option could be to extend the cage, a finger, or a similar spacer element downwards using a calibration plate (e.g., a magnetic washer) or some other mechanical extension. This is more complex, but achieves the same effect. This could also be achieved (e.g., in cases of poor accessibility) by using a cage / finger extended by the thickness of the washer, which is specifically designed and used for calibration purposes.

[0186] If a zeroing occurs, this must be documented under the event or fault messages with a time stamp and stored in a retrievable manner.

[0187] If the measurements of spindle height and screwdriver distance show that a nut has not been fully threaded, the threading process must be repeated automatically; at least for a number of repetitions that the screwdriver automatically performs when it again determines that the nut is not OK.

[0188] LIST OF REFERENCE SYMBOLS

[0189] 1 screw

[0190] 2 Screw curve 3 Screw head

[0191] 3a, 3b, 3c Damage

[0192] 5 threads

[0193] 10, 1000 screw tools

[0194] 11 Spindle 12, 100 screw tool head

[0195] 13 Screw must

[0196] 14, 1100 screwdriver drive

[0197] 16, 1200 downforce

[0198] 20 Object 21 Screw base

[0199] 101 first spindle unit

[0200] 102 second spindle unit

[0201] 110 spindle

[0202] 110a drive side 110k head side

[0203] 111 first spindle

[0204] 112 second spindle

[0205] 120 second spindle

[0206] 121, 122 Sleeve 130 Screwing tool

[0207] 131, 132 Screwing tools / screwdriver socket

[0208] 141, 142 cage

[0209] 200 housing frames

[0210] 201 upper wall 202, 204 side walls

[0211] 203 lower wall

[0212] 300 Structure

[0213] 301 rods

[0214] 302 Linkage plate 303 Rotary element

[0215] 400 carrying device

[0216] 1001 steps

[0217] 1003 steps

[0218] 1005 steps

[0219] 1006 steps

[0220] 1008 steps

[0221] 1200 drive unit

[0222] 1201 first output unit

[0223] 1202 second output unit

[0224] 1210 first drive unit

[0225] 1220 second drive unit

[0226] A distance measurement

[0227] Al, A2 Distance dimension

[0228] D Document d, dl, d2 Distance

[0229] M torque

[0230] MA measurement approach

[0231] ME measuring device

[0232] N Zero

[0233] W Repetition

[0234]

Claims

CLAIMS 1. A screwing tool head (100) comprising at least one spindle unit (101, 102) designed to receive a screwing means (130, 131, 132) for screwing in a screw (1) or similar screw element, wherein the screwing tool head (100) is designed for installation in a screwing tool (1000), in particular an automatic screwing machine, and the spindle unit (101, 102) comprises: - a spindle (110, 111, 112) arranged axially of the spindle unit, having a drive side (110a) and a head side (110k), wherein the spindle is designed to be coupled on the drive side to an output unit (1200) of the automatic screwing machine and rotatable thereover, and the screwing means (130, 131, 132) for engagement with a screw head (3) of the screw (1) can be accommodated on the head side of the spindle (110, 111, 112), - a reference structure extending at least partially along the spindle unit (101, 102), which is axially displaceable relative to the spindle and which is held on the spindle unit (101, 102) and relative to which the spindle is rotatable, characterized in that - a measuring attachment (MA) designed for a distance measurement (A) is attached to the spindle (130, 131, 132) between the drive side (110a) and the head side (110k), and - a measuring device (ME) is attached to the reference structure between the head side (110k) of the spindle and the measuring attachment (MA) for the distance measurement (A) and interacting with the measuring attachment, OR - a measuring device (ME) designed for distance measurement (A) is mounted on the spindle (130, 131, 132) between the drive side (110a) and the head side (110k), and - a measuring attachment (MA) is attached to the reference structure between the head side (110k) of the spindle and the measuring device (ME) for the distance measurement (A) and interacting with the measuring device (ME), and - an additional spacer element to the reference structure or one formed with the reference structure, wherein the spacer element is designed to be placed on a screw base.

2. Screwing tool head (100) according to claim 1, characterized in that the spindle unit (101, 102) is designed such that when the spacer element is attached, the screwing means (130, 131, 132) received on the head side of the spindle (130, 131, 132) can be attached to the screw head (3) in such a way that it is in contact with the screw head (3), wherein it can be seen by means of the distance measurement (A) that the screw means (130, 131, 132) is in engagement with the screw head (3).

3. Screwing tool head (100) according to claim 1 or 2, characterized in that - the spacer element is provided and / or designed as a distance-maintaining element between the screw base and the reference structure, and / or - the spacer element is held on and / or with a stop to the reference structure and by the reference structure.

4. Screwing tool head (100) according to one of claims 1 to 3, characterized in that the spacer element comprises one or more of the elements which are selected from the group of elements arranged individually or in pairs, consisting of: a plate, a finger, a pin, a tube, a cage, in particular wherein the tube and / or the cage is designed to surround the head side (110k) and the screwing means (130, 131, 132).

5. Screwing tool head (100) according to one of claims 1 to 4, characterized in that the reference structure is formed as a sleeve (121, 122) extending off-axis of the spindle unit and surrounding the spindle, which extends off-axis of the spindle unit and surrounds the spindle, in particular wherein the spacer element in the form of a tube and / or the cage (141, 142) is aligned with the sleeve (121, 122) and is designed to surround the head side (110k) and the screw means (130, 131, 132).

6. Screwing tool head (100) according to one of the preceding claims, characterized in that the spacer element placed on a screw base is designed with a stop to the reference structure for displacing the reference structure axially and relative to the spindle (110, 111, 112), wherein a relative displacement path between the reference structure and the spindle (110, 111, 112) is detected by the measuring device (ME) cooperating with the measuring attachment (MA), - in particular, wherein the attached cage (141, 142) is designed with a stop to the sleeve (121, 122) and is held by the sleeve (121, 122) for displacing the sleeve (121, 122) axially and relative to the spindle (110, 111, 112), wherein a relative displacement path between the sleeve (121, 122) and the spindle (110, 111, 112) is detected by the measuring device (ME) cooperating with the measuring attachment (MA).

7. Screwing tool head (100) according to one of the preceding claims, characterized in that the distance measurement is designed to indicate a distance measurement (Al, A2), in particular by means of a relative displacement path between the reference structure and the spindle, wherein the distance measurement (Al, A2) set in relation to a distance threshold value indicates that the screwing means (131, 132) is in engagement with the screw head (3).

8. Screwing tool head (100) according to one of the preceding claims, characterized in that - the measuring attachment (MA) is designed as a measuring plate around the spindle (110, 111, 112), and / or - the measuring device (ME) is a non-contact measuring device, in particular for detecting a measuring pulse transit time or a phase-sensitive measuring signal between the measuring attachment (MA) and the measuring device (ME), preferably a measuring device (ME) based on a light signal, a radio signal or similar electromagnetic measuring signal or a sound measuring signal between the measuring attachment (MA) and the measuring device (ME).

9. Screwing tool head (100) according to one of the preceding claims, characterized in that the measuring attachment (MA) and the measuring device (ME) are arranged along a distance measuring section extending axially along the spindle unit (101, 102), in particular wherein the measuring section extends along the spindle (110, 111, 112) between an upper end of the sleeve and the drive side (110a).

10. Screwing tool head (100) according to one of the preceding claims, characterized by a calibration ring, in particular a washer, wherein the calibration ring is held with a stop to the reference structure, in particular by a sleeve and by the sleeve (121, 122), and which is designed to surround the head side (110k) and the screw means (130), wherein the calibration ring is further designed to be placed on a screw base, wherein the calibration distance set by the calibration ring for displacing the sleeve (121, 122) axially and relative to the spindle (110, 111, 112) is previously known and can be determined.

11. Screwing tool head (100) according to one of the preceding claims, characterized in that the spindle (110, 111, 112) and / or the reference structure is resiliently mounted, in particular is spring-loaded.

12. Screwing tool head (100) according to one of the preceding claims, characterized in that the measuring device (ME) is designed to transmit and / or receive an evaluation and / or information signal, wherein the evaluation and / or information signal contains one or more of the default or evaluation information selected from the group of default or evaluation information consisting of: - an offset value for a screw head of a screw, in particular a screw head with a collar, - a tolerance value for a screw head of a screw, - a projection value for the projection of a screw head to the screw base, - a calibration distance for moving the sleeve axially and relative to the spindle, - a distance threshold that indicates that the screwing tool is applied to the screw head.

13. Screwing tool head (100) according to one of the preceding claims, characterized in that a measurement evaluation unit is designed to detect one or more of the evaluation variables which are selected from the group of evaluation variables consisting of: - Number of confirmed and / or non-confirmed threading operations in which the screwing tool mounted on the head side of the spindle engages the screw head, in particular is in contact with the screw head, - one or more threshold values ​​for the number of threading operations and / or for a time period of a threading operation.

14. Screwing tool head (100) according to one of the preceding claims, characterized in that the screwing tool head is designed as a double screwing tool head, wherein the spindle unit (101, 102) is formed as a first spindle unit (101) and a second spindle unit (102) is formed analogously to the spindle unit.

15. Screwing tool (1000), in particular a screwing machine or similar partially or fully automated screwing tool, with a screwing tool head according to one of the preceding claims 1 to 14 and with a screwdriver drive for driving at least one spindle of the screwing tool head (100).

16. Screwing tool (1000) according to claim 15, characterized in that the screwing tool head is designed as a double screwing tool head with a first and a second spindle unit (101, 102), and the screw drive has an output with a first output unit for driving a first spindle (111) of the first spindle unit (101) and a second output unit for driving a second spindle (112) of the second spindle unit (102).

17. Screwing tool (1000) according to claim 15 or 16, characterized in that the screwdriver drive is designed to implement the drive of the first and second spindles (110, 111, 112) synchronized with one another by means of the output.

18. A method for screwing in a screw (1) with a screwing tool (1000) according to one of claims 15 to 17, comprising the steps: - optionally screwing in the screw (1) up to a protrusion dimension, - Threading the screw (1), if possible in such a way that, when the spacer element is in place, the screwing means (130, 131, 132) held on the head side of the spindle (110, 111, 112) is placed on the screw head (3) in such a way that it is in contact with the screw head (3), - Checking whether the screwing means (130, 131, 132) is in engagement with the screw head (3) by means of the measuring device (ME) attached to the reference structure, which is designed for distance measurement (A) and interacts with the measuring attachment (MA) attached to the spindle (110, 111, 112), OR - Checking whether the screwing means (130, 131, 132) is in engagement with the screw head (3) by means of the measuring attachment (MA) attached to the reference structure, which is designed for distance measurement (A) and interacts with the measuring device (ME) attached to the spindle (110, 111, 112), - screwing in the screw (1) with the screwing tool (100), whereby the screw (1) is only screwed in when the distance measurement (A) confirms that the screwing means (131, 132) received on the head side of the spindle (110, 111, 112) is in engagement with the screw head.

19. Computer program product designed to carry out the method for screwing in a screw with a screwing tool according to one of claims 15 to 17, when the computer program product is carried out with a screwing tool according to one of claims 15 to 17.

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