Part presenter for presenting a blind rivet nut to a setting tool

Abstract

A part presenter (1) is designed for presenting a blind rivet nut (4) to a setting tool, with a housing (2) and a receptacle (3) formed by the housing (2). Into the housing (2) at least one blind rivet nut (4) can be inserted. The blind rivet nut (4) in the housing (2) is accessible for a screwing tool (21) of the setting tool through an opening (5). An end stop (7) is arranged in the receptacle (3) opposite the opening (5), which end stop (7) forms a stop for the blind rivet nut (4) and can be moved axially along a longitudinal axis of the receptacle (3) from a first position into a second position. In its second position, the end stop (7) comes into operative contact with a sensor element (15), wherein the sensor element (15) is connectable to a control unit of the setting tool in a data-exchanging manner.

Description

[0001] The invention relates to a part presenter for presenting a blind rivet nut to a setting tool. Furthermore, the invention relates to an arrangement of a part presenter and a setting tool and a method for presenting a blind rivet nut to a setting tool.

[0002] In motor vehicle manufacture it is usual that various components such as strips, rails, equipment etc. are fastened to thin-walled components, such as sheet metal or profiles of aluminium, for example. A common method of connecting components is to use a fastener having a screw thread.

[0003] Blind fasteners are fastening elements that are to be arranged in an opening, for example, in a through hole of a metal sheet or any other sheet or workpiece. They are commonly used to secure a plurality of work pieces together when it is difficult or impossible to access the blind side of one of the work pieces. Blind fasteners have generally incorporated a sleeve or shank that expands and bends during installation. A blind fastener can be a blind rivet, a blind rivet nut, a self-drilling self-tapping screw, or similar fasteners. A blind fastener can provide an internal thread and thus render possible a screw connection to metal sheets or workpieces, the wall thickness of which is not sufficient to embody a thread. A blind rivet nut typically has an elongate body, that is generally cylindrical or hexagonal in cross section, and hollow for the major part of its length, with one end being either closed (blind) or open. Part of the hollow portion is threaded to receive a setting tool or bolt.

[0004] A blind fastener setting device or setting tool for blind fasteners is used to automatically set the blind fastener in the opening of the workpiece. The blind fastener has, in a non-deformed state, a hollow cylindrical rivet shank at the one end of which a radially extending set head is embodied and on the other end of which an internal thread is formed (for instance for a blind rivet nut) and / or a mandrel may be arranged (for example for a blind rivet). It is known to use a bolt having an external thread cooperating with the internal thread of the blind rivet nut to set the blind rivet nut in the hole. The internal thread of the blind rivet nut engages with the external thread of the bolt.

[0005] The blind fastener is inserted with the rivet shank first into the hole until the rivet head contacts the sheet. By start-up of the blind fastener setting device, the bolt or the mandrel and thus the thread region are then moved axially backwards from the blind fastener and the sheet, whereby a compression of the rivet shank occurs. A bead or a bulge is formed at a desired deformation point at the workpiece side facing away from the rivet head. The blind fastener is thus held captively in the hole (or opening).

[0006] To remove the setting device from the set blind fastener, pressure on the bolt is relieved and it is rotated in the drill-off direction. The blind fastener setting device is then available for a new setting operation.

[0007] US 11,738,384 B2 describes a setting tool comprising: a first electric motor with a first drive shaft, which is arranged in a first housing portion and is connected to a tool housing portion via a first transmission; a tool shaft connected to a screw tool, and the screw tool is movable between a retracted and an extended position; a feeder with a fastener delivery tube, the delivery tube for delivering blind fasteners in front of the screw tool when in the retracted position; a second electric motor with a second drive shaft is arranged in a second housing portion and is connected to the tool housing portion via a second transmission; and the delivery tube merges with the tool housing portion through a receiver assembly, the receiver assembly comprising an interface channel connecting the delivery tube with the tool housing portion, such that the screw tool can engage with the blind fastener.

[0008] US 7,346,970 B2 discloses a setting device for blind fasteners having a single electric motor with a drive shaft that is positioned in a first housing part and is connected via a transmission means to a tool housing part. The tool housing part is laterally offset relative to the drive shaft and extends in parallel with the drive shaft. A tool shaft is arranged in the tool housing part and has non-rotationally connected thereto a screw type tool which projects from the front end of the tool housing part. Locking means to which the tool housing part and the tool shaft can be coupled together in non-rotational fashion, or decoupled, anti-rotation means with which the tool shaft can be blocked against rotation or can be released for rotation are also provided.

[0009] Such setting tools may be cumbersome and need a minimum time to perform all the steps and motions needed to perform the crimping and then become available for the next setting operation. The setting of blind fasteners is often burdensome, since several steps are necessary to catch the blind fastener and to orient it correctly. Besides, the forces and motions needed to engage such blind fasteners mostly imply complicated systems, which cannot be compact in view of the forces needed.

[0010] A problem with the known setting tools is that a misalignment between the blind rivet nut to be inserted, i.e. its internal thread, and the screwing tool of the setting tool, i.e. its external thread, cannot be detected or can only be detected with considerable technical effort. In the worst case, such cross-threads can lead to damage to the screwing tool. In the case of hexagonal blind rivet nuts, cross-threads can be detected by means of torque monitoring. This is not possible with cylindrical blind rivet nuts, i.e. those that are round in cross-section.

[0011] It is hence an object of the present invention to at least alleviate the aforementioned shortcomings. More particularly one objective of the present invention is to provide a device with which thread irregularities can be detected when picking up a blind rivet.

[0012] To this aim, according to the invention, it is provided a part presenter according to claim 1. Preferred embodiments are described in the dependent claims.

[0013] The problem is solved by providing a part presenter for presenting a blind rivet nut to a setting tool, with a housing and a receptacle formed by the housing, into which at least one blind rivet nut can be inserted and which is accessible for a screwing tool of the setting tool through an opening, with an end stop arranged in the receptacle opposite the opening, which end stop forms a stop for the blind rivet nut and can be moved axially along a longitudinal axis of the receptacle from a first position into a second position, in which the end stop comes into operative contact with a sensor element, wherein the sensor element is connectable to a control unit of the setting tool in a data-exchanging manner. The part presenter makes it possible to quickly and easily detect a misalignment, especially a cross-thread between the blind rivet nut and the setting tool, thus preventing damage to the setting tool. Another major advantage of the invention is that it does not matter whether the blind rivet nuts are cylindrical or hexagonal. This is because the misalignment causes the blind rivet nut to move towards the end stop, regardless of the outer shape.

[0014] It is preferable to have a resilient element between the end stop and the housing so that the end stop can be moved from its first position to its second position against a spring force. The resilient element dampens an axial movement of the end stop from its first position to its second position. This allows the pressure at which the blind rivet nut reaches the end stop and thus makes contact with the sensor element to be defined. The resilient element can be designed in a variety of ways and may, for example, take the form of a spring, in particular a tension or compression spring. It may also be provided with an elastically designed means between the end stop and the housing, such as a rubber ring or the like.

[0015] The end stop can be designed in a variety of ways. In one preferred design, the end stop has a disc-shaped base element that is perpendicular to the longitudinal axis of the receptacle, from which a guide element extends vertically. A circumferential surface of the base element can essentially lie flat against an inner wall of a receptacle that is, for example, cylindrical in shape.

[0016] The guide element is preferably at least partially cylindrical or sleeve-shaped. The guide element extends essentially vertically from the base element in a direction opposite to the opening, so that the end stop in this design is T-shaped.

[0017] The end stop interacts with the sensor element in its second position. In this regard, it is advantageous if the guide element has a head part at its free end with an active surface that comes into active contact with the sensor element. The active surface can be specially designed for interaction with the sensor element. This means that the active surface can be designed and have the appropriate properties depending on the type of sensor. The sensor element can be a sensor known to the expert that is suitable for the task at hand. For example, but not limited to, it can be a pressure sensor, distance sensor, optical sensor, magnetic sensor, capacitive sensor or the like.

[0018] The head part and guide element can be designed as a single piece. However, it is also possible to design the head part of the guide element as a separate component that is attached to the guide element using a fastener. This design simplifies the assembly and maintenance of the end stop.

[0019] In one embodiment of the invention, the resilient element can be provided as a spiral compression spring that engages around the guide element and is supported at its ends, on the one hand, on a shoulder of the housing and, on the other hand, on the base element. Such a spiral compression spring dampens the movement of the end stop in the direction of its second position.

[0020] The sensor element may be located inside the housing and positioned so that it interacts with the end stop when it is moved to its second position. Alternatively, the sensor element may be located close to the housing, but in particular outside the housing within reach of the end stop.

[0021] In one embodiment, the part presenter can be part of a setting tool or can be connected to it. For this purpose, it is advantageous for the part presenter to have means for fastening it to a housing of the setting tool. These can, for example, be in the form of a flange connection or screw connections and enable reversible fastening. The part presenter can also be attached to a holding device that can be moved relative to the setting tool.

[0022] Furthermore, it may be provided that the part presenter comprises means for attachment to an automated handling device. The handling device, e.g. a robot, can position the part presenter close to a setting tool and ensure that a blind rivet nut is properly presented. Alternatively, the part presenter can be positioned in a stationary manner on a device, with the setting tool being attached to a handling device and being movable from this to the part presenter.

[0023] Furthermore, the invention relates to an arrangement for setting a blind rivet nut comprising a setting tool with a screwing tool at its free end and a part presenter, according to one of the preceding claims. The advantages and designs of the part presenter explained above can be transferred to the arrangement. The part presenter can advantageously be arranged in relation to the setting tool in such a way that the external thread of the screwing tool can interact with an internal thread of a blind rivet nut present in the receptacle of the part presenter. The sensor element transmits sensor signals to the setting tool, in particular to its control unit, which can then control the setting tool accordingly. If the part presenter detects a cross-thread or the threads are canted, in particular if the sensor element comes into active contact with the end stop, a stop signal can be transmitted to the setting tool.

[0024] Furthermore, the invention concerns a method for presenting a blind rivet nut to a setting tool comprising the steps of providing a setting tool having a screwing tool for setting blind rivet nuts, the free screw-shaped end of which is rotatably drivable and has an external thread, providing a part presenter as described above, providing a blind rivet nut with an internal thread in the receptacle of the part presenter and positioning the blind rivet nut in a loading position, inserting the screwing tool along a longitudinal axis of the blind rivet nut into the receptacle and rotationally engaging the internal thread of the blind rivet nut, advancing the blind rivet nut towards and against the end stop due to a cross-thread so that the end stop is moved from its first position to its second position in which the end stop interacts with the sensor element, transmitting a signal from the sensor element to the control unit of the setting tool, stopping the forward and rotational movement of the screwing tool.

[0025] The method according to the invention enables a fast and reliable detection of a cross-thread, independent of the outer shape of the blind rivet nut.

[0026] It can be advantageous to move the screwing tool together with the blind rivet nut out of the receptacle after stopping. A worker can remove the blind rivet nut from the screwing tool by hand.

[0027] In a preferred embodiment, the screwing tool and the blind rivet nut are moved back to the loading position, where the blind rivet nut is held in place by the clamping device, and then turning the external thread of the screwing tool in a backward movement and in the opposite direction to unscrew it from the internal thread of the blind rivet nut. The blind rivet nut can then be removed from the receptacle and a new blind rivet nut can be provided. With this design, it is possible to remove the blind rivet nut automatically.

[0028] The invention is explained in more detail below using an example of the invention, which is shown in the drawing. It shows Figure 1a perspective cross-section of a part presenter with blind rivet nut, Figure 2another perspective cross-section of a part presenter with blind rivet nut and interaction with a sensor element, Figure 3-7a preferred design of the method for presenting a blind rivet nut to a setting tool.

[0029] A part presenter 1 comprises a housing 2 that can be attached to a handling device, for example. Alternatively, the part presenter can also be installed on a device and located in the handling area of an automated setting tool that is not shown and is in turn attached to a handling device. Of course, it is also possible to attach the part presenter 1 to a setting tool itself.

[0030] The housing 2 encloses a receptacle 3 that is designed to receive a blind rivet nut 4. The receptacle 3 may, for example, have a hollow cylindrical shape. The receptacle 3 is accessible via an opening 5 integrated at one end of the housing 2. A clamping device 6 may be present in the receptacle 3, which, with clamping jaws, at least partially radially engages the circumferential surface of the blind rivet nut 4. This allows the blind rivet nut 4 to be held in a loading position. Alternatively, the blind rivet nut 4 can simply be inserted into the receptacle 3 and positioned in the loading position. The clamping jaws of the clamping device 6 can be designed to move automatically and can be operated hydraulically, pneumatically or electrically, for example. The blind rivet nut 4 is not shown being inserted into the receptacle 3, but it can be done automatically using the appropriate means. Of course, it is also possible to insert the blind rivet nut 4 into the receptacle 3 by hand.

[0031] At one end of the receptacle 3, opposite the opening 5, there is an end stop 7 against which a blind rivet nut 4 can be placed with its foot part 8. The end stop 7 can have a disc-shaped base element 9 that is positioned at right angles to the longitudinal axis of the receptacle 3. The material used to make the end stop 7 can be plastic, metal or a combination of the two. The end stop 7, in particular the base element 9, can be radially mounted and, for example, can be placed with its circumferential surface against an inner surface of the receptacle 3. A sliding sleeve or the like can also be advantageous for mounting the end stop 7 in the receptacle 3.

[0032] In the design shown, there is an aperture 10 in the housing 2 opposite the opening 5. Between the receptacle 3 and the aperture 10 is a first circumferential shoulder 11, which forms a transition to a diameter-reduced area 12. The diameter-reduced area is in turn flanked by a second circumferential shoulder 13, which marks the end of the aperture 10. The aperture 10 may be surrounded by an outer housing wall 14.

[0033] The end stop 7 can be moved between a first and a second position by applying a force F axially to the blind rivet nut 4, see figure 1. It is preferable for the end stop 7 to come into contact with the blind rivet nut 4 in the first position and for this contact to continue until the second position is reached, i.e. the end stop 7 is preferably in permanent contact with the blind rivet nut 4. In the design shown in figure 2, the movement of the end stop 7 to its second position is limited by the first shoulder 11, against which the end stop 7 rests axially. A sensor element 15 can be provided on the first shoulder 11, which makes an active contact with the end stop 7 when the end stop 7 reaches its second position. In the depicted design, the sensor element is shown at another exemplary position, namely, outside of the housing 2, but within the outer housing wall 14 of the part presenter 1.

[0034] The sensor element 15 is connected to a setting tool, in particular to a control unit of the setting tool, for the exchange of data. Sensor signals generated by the sensor element 15 can be transmitted to the control unit by wire or wirelessly. The control unit may comprise an evaluation unit, which evaluates the sensor signal and transmits corresponding control commands to the control unit.

[0035] In the design shown, a resilient element 16 in the form of a spiral compression spring rests with its free ends on the second shoulder 13 and the end stop 7. In the first position of the end stop 7, the resilient element 16 is pre-tensioned. If the end stop 7 moves to its second position, the resilient element 16 is compressed and the end stop 7 moves against the spring force of the resilient element 16 to its second position. The end stop 7 can be moved back to its first position when the resilient element 16 is decompressed.

[0036] Alternatively, it may be provided that a resilient element 16 in the form of a tension spring is present in the receptacle 3, and that the end stop 7 can be moved into its second position against the spring force of the resilient element.

[0037] Furthermore, it may be provided that the resilient element 16 is designed as a leaf spring and dampens a movement of the end stop 7 into its second position.

[0038] It is also possible to provide a resilient element 16 with an elastic design and, for example, to provide an elastic rubber ring between the second step 13 and the base element 9 of the end stop 7.

[0039] In the design shown, a guide element 17 is provided on the base element 9 of the end stop 7, projecting vertically from the latter. The guide element 17 can be designed as a sleeve-shaped or cylindrical element. At its free end, the guide element 17 has a head part 18 that projects through the aperture 10. The head part 18 can be designed as part of the guide element 17. However, it can also be provided that the head part 18 - as shown in the design - is present as a separate component. In order to attach the head part 18 to a centre part located between the head part 18 and the base element 9, a bore 19 can be provided in the centre part and the head part 18, so that the head part 18 can be connected to the centre part by means of a fastening means 20 that passes through the head part 18.

[0040] In the illustrated design, the head part 18 protrudes slightly over the edge of the housing 2 and is located adjacent to a sensor element 15. The sensor element 15 can, for example, be attached to the housing 2 or otherwise arranged at a distance from the housing 2. In order to explain the principle of the invention, the sensor element 15 is sketched as a pressure switch or pressure element. However, the principle of the invention can be realised with different types of sensors as the sensor element 15 and is not limited to the design shown. The placement of the sensor element 15 is also not limited to the design variant shown. As already mentioned, the sensor element 15 can also be located in the housing 2.

[0041] The procedure is illustrated schematically in Figures 3 to 7. A blind rivet nut 4 is provided in the receptacle 3 and positioned in a loading position so that the foot part 8 of the blind rivet nut 4 essentially abuts the end stop 7 or is adjacent to the end stop 7, see figure 3. In its loading position, the blind rivet nut 4 does not exert any pressure on the end stop 7, so that the end stop 7 remains in its first position. The blind rivet nut 4 has an internal thread that is accessible via the opening 5 of the receptacle 3. The longitudinal axis of the blind rivet nut 4 is advantageously coaxial with the longitudinal axis of the receptacle 3. The head part 18 of the end stop 7 is adjacent to the sensor element 15, but is not in active contact with it, i.e. no sensor signal is generated by the sensor element 15.

[0042] A setting tool with a screwing tool 21 is provided. The free end 22 of the screwing tool 21 is helically shaped and has an external thread. The screwing tool 21, or more precisely its free end 22, is connected to a motor in a torque-transmitting manner, which drives it in a rotating manner. In addition, the screwing tool 21, or its free end 22, can be moved back and forth along its longitudinal axis.

[0043] The part presenter 1 is presented in front of the screwing tool 21. For this purpose, the part presenter 1 can be mounted on an articulated arm of a handling device, e.g. a robot. The longitudinal axis of the blind rivet nut 4 is advantageously coaxial with the longitudinal axis of the free end 22 of the screwing tool 21. The screwing tool 21, in particular its free end 22, is moved forward and set in rotation, see figure 5, indicated by the black arrows. The free end 22 is moved through the opening 5 into the receptacle 3 and into the internal thread of the blind rivet nut 4. The external thread of the screwing tool 21 engages in the internal thread of the blind rivet nut 4, see figure 6. A slight axial movement of the blind rivet nut 4 is compensated by the spring-loaded movement of the end stop 7 and does not cause the end stop 7 to reach its second position.

[0044] In a normal state, the free end 22 with its external thread is screwed into the internal thread of the blind rivet nut 4 up to a defined point and the blind rivet nut 4 is removed from the receptacle 3 by moving the screwing tool 21 back.

[0045] If the threads become jammed, for example because the internal thread of the blind rivet nut 4 is damaged, the blind rivet nut 4 is at an angle in receptacle 3 or the screw tool 21 is inserted into the receptacle 3 at an angle, the forward movement of the screwing tool 21 and its rotation should be stopped immediately to prevent any damage to the setting tool.

[0046] The preferred embodiment of the invention solves this problem as follows: As the forward movement of the screwing tool 21 continues, as indicated in figure 7, the blind rivet nut 4 moves with the screwing tool 21 in the opposite direction to the opening 5 against the end stop 7. The blind rivet nut 4 exerts pressure on the end stop 7 and moves it from its first position against the spring force of the resilient element 16 in the direction of its second position. The head part 18 of the end stop 7 is thereby moved along the longitudinal axis of the receptacle 3 and comes into operative contact with the sensor element 15. The head part 18 can have an active surface that is designed and intended to interact with the sensor element 15. For this purpose, the active surface can, for example, have a friction-reducing coating or an advantageous shape or geometry.

[0047] As soon as the head part 18 comes into operative contact with the sensor element 15 and - as shown in the simplified figure - actuates the pressure switch, a sensor signal is generated by the sensor element 15, which is transmitted to a control unit of the setting tool either wirelessly or by wire. An evaluation unit connected to the control unit can analyse the sensor signal and transmit a control command to the control unit, causing the forward and rotational movement of the screwing tool 21 to stop.

[0048] The setting tool 21 can be retracted in a controlled manner in a subsequent step so that the blind rivet nut 4 can be removed. This can be done, for example, by moving the blind rivet nut 4 into its loading position by simply moving the screwing tool 21 in a backward direction and preferably without any further rotational movement. In the loading position, the clamping device 6 can secure the blind rivet nut 4 radially and the external thread of the screwing tool 21 can be moved out of the internal thread of the blind rivet nut 4 by an opposite rotational movement and backward movement of the screwing tool 21. Alternatively, the blind rivet nut 4 can of course also be removed manually by an operator from the free end 22 of the screwing tool 21.

[0049] The invention enables the rapid detection of a cross-thread, thus preventing damage to the setting tool. Moreover, existing setting tools can be retrofitted with the invention. The device 1 is easy to maintain and can be easily adapted to the tasks at hand. For example, various types of sensors can be used as sensor element 15.

Claims

1. Part presenter (1) for presenting a blind rivet nut (4) to a setting tool, with a housing (2) and a receptacle (3) formed by the housing (2), into which at least one blind rivet nut (4) can be inserted and which is accessible for a screwing tool (21) of the setting tool through an opening (5), with an end stop (7) arranged in the receptacle (3) opposite the opening (5), which end stop (7) forms a stop for the blind rivet nut (4) and can be moved axially along a longitudinal axis of the receptacle (3) from a first position into a second position, in which the end stop (7) comes into operative contact with a sensor element (15), wherein the sensor element (15) is connectable to a control unit of the setting tool in a data-exchanging manner.

2. Part presenter (1) according to claim 1, characterised in that a resilient element (16) is provided between the end stop (7) and the housing (2), so that the end stop (7) can be moved from its first position to its second position against a spring force.

3. Part presenter (1) according to claim 1 or 2, characterised in that the end stop (7) has a disc-shaped base element (9) which is perpendicular to the longitudinal axis of the receptacle (3) and from which a guide element (17) extends vertically.

4. Part presenter (1) according to claim 3, characterised in that the guide element (17) is at least partially cylindrical or sleeve-shaped.

5. Part presenter (1) according to one of claims 3 or 4, characterised in that the guide element (17) has at its free end a head part (18) with an active surface, which comes into active contact with the sensor element (15).

6. Part presenter (1) according to claim 5, characterised in that the head part (18) of the guide element (17) is provided as a separate component and is attached to the guide element (17) by means of a fastening means (20).

7. Part presenter (1) according to one of the previous claims, characterised in that the sensor element (15) is present in the housing (2) or is arranged close to the housing (2) within reach of the end stop (7).

8. Part presenter (1) according to one of the previous claims, characterised in that the resilient element (16) is designed as a spiral compression spring which engages around the guide element (17) and is supported at its ends, on the one hand, on a shoulder (13) of the housing (2) and, on the other hand, on the base element (9).

9. Part presenter (1) according to one of the previous claims, characterised in that the part presenter (1) has means for attachment to a housing of the setting tool.

10. Part presenter (1) according to one of the previous claims 1 to 8, characterised in that the part presenter (1) comprises means for attachment to an automated handling device.

11. An assembly for setting a blind rivet nut (4) comprising a setting tool having a screwing tool (21) at its free end and a part presenter (1), according to one of the preceding claims.

12. A method for presenting a blind rivet nut (4) to a setting tool comprising the steps of providing a setting tool having a screwing tool (21) for setting blind rivet nuts (4), the free screw-shaped end (22) of which is rotatably drivable and has an external thread, providing a part presenter (1) according to one of claims 1 to 10, providing a blind rivet nut (4) with an internal thread in the receptacle (3) of the part presenter (1) and positioning the blind rivet nut (4) in a loading position, inserting the screwing tool (21) along a longitudinal axis of the blind rivet nut (4) into the receptacle (3) and rotationally engaging the internal thread of the blind rivet nut (4), advancing the blind rivet nut (4) towards and against the end stop (7) due to a cross-thread so that the end stop (7) is moved from its first position to its second position in which the end stop (7) interacts with the sensor element (15), transmitting a signal from the sensor element (15) to the control unit of the setting tool, stopping the forward and rotational movement of the screwing tool (21).

13. A method according to claim 12, characterised in that after stopping, the screwing tool (21) together with the blind rivet nut (4) is moved out of the receptacle (3).

14. A method according to claim 12, characterised in that after stopping, the screwing tool (21) together with the blind rivet nut (4) is moved back to the loading position, in which the blind rivet nut (4) is held in its position by the clamping device (6), and the external thread of the screwing tool (21) is turned out of the internal thread of the blind rivet nut (4) in a backward movement and opposite rotation.

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