Device and method for setting a connecting element on a workpiece

Abstract

A device for setting a connecting element on a workpiece includes a setting unit having a setting head which is movable in a feed direction into a working position, the connecting element can be fastened on the workpiece by the setting head, and a feed unit can feed the connecting element to the setting head. The feed unit is movable in the feed direction from an initial position into an intermediate position for transferring a connecting element to the setting head. A method for setting a connecting element on a workpiece by using the device is also provided.

Claims

1. A device for performing a setting process for setting a connecting element on a workpiece, the device comprising: a control device controlling operation of the setting process; a setting unit having a setting head being movable in a feed direction into a working position, said setting head being configured to fasten the connecting element on the workpiece; and a feed unit for feeding the connecting element to said setting head, said feed unit being movable in said feed direction from a starting position to a freely adjustable intermediate position for permitting a transfer of the connecting element to said setting head at different positions between said starting position and said working position.

2. The device according to claim 1, wherein said setting head and said feed unit are movable independently of one another toward said working position.

3. The device according to claim 1, wherein said setting head and said feed unit are movable parallel to one another.

4. The device according to claim 1, which further comprises a carrier on which said feed unit is mounted for linear displacement.

5. The device according to claim 1, wherein said control device is configured to adapt said intermediate position based on a geometry of the workpiece.

6. The device according to claim 1, wherein said control device is configured to select said intermediate position in such a way that a travel path of said setting unit between two consecutive setting processes is optimized for a geometry of the workpiece.

7. The device according to claim 1, wherein said control device is configured to select said intermediate position in such a way that said intermediate position is retracted dynamically during successive setting processes and optionally as a function of a geometry of the workpiece.

8. The device according to claim 1, wherein said control device is configured in such a way that said feed unit remains in said intermediate position for a plurality of setting processes.

9. The device according to claim 1, wherein said feed unit is configured to feed the connecting element to said setting head in a direction transverse to said feed direction.

10. The device according to claim 1, wherein said feed unit has at least one of a magazine for storing a plurality of connecting elements or a connection directly or through a feed tube to a feed device for the connecting elements.

11. The device according to claim 1, which further comprises a carrier on which said setting unit and said feed unit are both disposed.

12. The device according to claim 11, wherein said carrier is curved or C-shaped and has an upper curved part and a lower curved part, said setting unit and said feed unit are fastened to said upper curved part, and a holder for the workpiece is disposed on said lower curved part.

13. The device according to claim 1, which further comprises: a die against which said setting head is moveable in said feed direction, said die having a base body; a die punch displaceable in said base body; and a drive mechanism adjustably controlling said die punch counter to said feed direction, said drive mechanism: causing said die punch to serve during operation as a support for setting the connecting element, or causing said die punch to reshape the connecting element during operation to establish a form-locking connection with the workpiece.

14. A device for carrying out a setting process for setting a connecting element on a workpiece, the device comprising: a die having a base body and a die punch displaceably disposed in said base body; a setting unit including a setting head being movable against said die toward the workpiece in a feed direction; said die punch serving during operation as a support for at least one of setting the connecting element or bringing about a reshaping of the connecting element to establish a form-locking connection between the connecting element and the workpiece; said die punch being moveable to a forward position and a retracted position for a multi-stage setting process; a drive mechanism for adjusting said die punch in a controlled manner counter to said feed direction; and a control device controlling operation of the setting process, said control device being configured to move said die punch during operation to said forward and said retracted positions; said control device being configured to carry out a first variant of the setting process in such a way that said setting head moves against the workpiece for setting the connecting element and said setting head presses the connecting element against said die punch for reshaping the connecting element and establishing the form-locking connection between the connecting element and the workpiece; and said control device being configured to control the setting process in such a way that a hole is first punched into the workpiece by the connecting element, then the connecting element is moved back, then said die punch is moved to said forward position, and then said setting head presses the connecting element against said die punch to reshape the connecting element.

15. The device according to claim 14, wherein said control device for controlling the setting process is configured to carry out a piercing process in a first step of the setting process.

16. The device according to claim 14, wherein said control device is configured to carry out a second variant of the setting process in such a way that: said setting head moves against the workpiece and the connecting element is inserted into the workpiece for setting the connecting element, and then said die punch is moved against the connecting element for reshaping the connecting element and establishing the form-locking connection between the connecting element and the workpiece.

17. The device according to claim 14, wherein said drive mechanism has a self-locking linkage or a toggle mechanism for adjusting said die punch.

18. The device according to claim 14, which further comprises: a curved carrier having a lower curved part; said die being disposed on said lower curved part; said drive mechanism being disposed at least partially inside said carrier; and said drive mechanism having a drive and an actuating rod extending laterally relative to said feed direction.

19. The device according to claim 14, wherein: said base body has an inner channel, said die punch is movable in said inner channel; said base body has a lateral opening connected to said inner channel for disposing of a punched slug; a flap is configured for closing said opening; and said flap is automatically shifted from a closed to an open position by a movement of said die punch.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

(1) The individual aspects of the device are explained below with reference to the drawings. The drawings show the following, in partially simplified representations:

(2) FIG. 1 shows a side view of a device for carrying out a setting process for setting a connecting element, comprising a setting unit and a feed unit that are in a starting position,

(3) FIG. 2 shows a partial enlarged view of the device according to FIG. 1, wherein the setting unit and feed unit are in a first intermediate position,

(4) FIG. 3 shows an enlarged partial view of FIG. 2, showing an enlarged view of a transfer of a connecting element from the feed unit to the setting unit,

(5) FIG. 4 shows a partial enlarged view of the device according to FIG. 1, in which the setting unit is in a setting position for carrying out the setting process and the feed unit is in the first intermediate position,

(6) FIG. 5 shows a partial enlarged view of the device according to FIG. 1, in which, starting from the situation according to FIG. 4, the feed unit is moved to a second intermediate position, while the setting unit remains in the setting position,

(7) FIG. 6A shows a partial enlarged view in the manner of a cross-section through the device in the region of a die with an overlying workpiece formed as a metal sheet, which is pressed by the setting unit against the die and with an adjustable die punch, which is in a retracted position during a piercing process,

(8) FIG. 6B shows an enlarged view of FIG. 6A in the region of the die for illustrating the discharge of a punched slug via a lateral opening in the die,

(9) FIG. 7A shows an illustration similar to FIG. 6A, wherein after the piercing process has taken place, the die punch is in a forward position,

(10) FIG. 7B shows an enlarged view of FIG. 7A, in which the connecting element is still in a pre-assembly position before a reshaping process, and

(11) FIG. 7C shows an enlarged view in the region of the die following a reshaping process, wherein a collar of the connecting element has been reshaped for a positive connection with the workpiece.

DESCRIPTION OF THE INVENTION

(12) In the drawings, like-acting parts are assigned the same reference numerals.

(13) The device 2 shown in the drawings is used in particular to carry out a multi-stage setting process in which a connecting element 4 is placed on a workpiece 6, in particular a metal sheet. The connecting element 4 is, for example, a press-in nut, a press-in bolt (screw) or alternatively a rivet. The connecting element 4 is, for example, a self-piercing connecting element, such as a self-piercing nut or a self-piercing rivet.

(14) The device 2 has a setting unit 8, by means of which the actual setting process, i.e. the pressing in of the connecting element 4, takes place in the workpiece 6. The device 2 also has a feed unit 10, which is designed for the particularly lateral feeding of the connecting element 4 to the setting unit 8. The setting unit 8 and feed unit 10 are arranged on a carrier 12. This is configuredas shown in the exemplary embodimentpreferably in the manner of a curved, in particular C-shaped carrier 12. This carrier has an upper curved part 12A and a lower curved part 12B.

(15) The device 2 further comprises a first drive 14, which is in particular an electric motor drive. This first drive 14 is associated with a tappet 16, which in particular may be moved by electric motor in a feed direction 18. The setting unit 8 is attached at the front end of the tappet 16. This unit is thus offset in the feed direction 18 by means of the tappet 16. The first drive 14 is fixed to the carrier 12, in particular to the front end of the upper curved part 12A.

(16) The device 2 further comprises a holder 20, furnished for supporting or holding the workpiece 6. In operation, the workpiece 6 rests on this holder 20. The holder 20 forms a multi-part die 22, the detailed structure of which is explained in greater detail in particular in connection with FIGS. 6 and 7. The holder 20 or die 22 are arranged on the lower curved part 12B opposite the setting unit 8.

(17) The multi-part die 22 generally has a base body 24 and a die punch 26 that is adjustable within the base body 24 (see also FIGS. 6 and 7). A drive mechanism 28 is furnished for adjusting the die punch 26. This comprises a second drive 30, which is also configured in particular as an electric motor. The drive mechanism 28 further comprises an actuating rod 32 that may be displaced in its longitudinal direction by means of the second drive 30. At its front end, it is connected to a linkage 34, which in turn is connected to the die punch 26.

(18) The setting unit 8 generally has a setting head 36. This setting head in turn has at its front end a hold-down 38 and a movable punch arranged therein, which is configured in particular as a punch sleeve 40. Preferably, an ejector pin 42 is additionally arranged within the punch sleeve 40, which serves for ejecting a punched slug 44 (see again FIGS. 6 and 7). The punch sleeve 40 generally serves to guide the connecting element 4 to the workpiece 6. In addition, the punch sleeve 40 is formed in a preferred embodiment as a piercing sleeve, so that a piercing process may be performed for producing a hole 46 in the workpiece 6.

(19) The feed unit 10 is attached to the carrier 12 by means of a linear guide 48 and may move to different positions in the feed direction 18. For the transfer of the connecting element 4 to the setting head 36, this setting head has a lateral feed opening 50 (see, in particular, FIG. 6B). The feed is thus generally lateral, and approximately perpendicular to the feed direction 18. For this purpose, the feed unit 10 has, in particular, a feed punch 52 or slide that may be extended in the transverse direction. This feed punch or slide is optionally operated pneumatically, hydraulically and in particular by an electric motor.

(20) Feeding the connecting elements 4 to the feed unit 10 takes place in the exemplary embodiment by means of a feed tube 54.

(21) The setting process is generally controlled by means of a control device 56. This control device controls in particular the first drive 14, the second drive 30, and the adjustment of the feed unit 10 along the linear guide 48 (which preferably also takes place by means of an electric motor drive) and, in addition, the operation of the feed punch 52.

(22) A first concept relates to the method of the feed unit 10 together with the setting unit 8 in the feed direction 18, in particular also the dynamic retraction of the feed unit 10 through a plurality of consecutive settling operations (working cycles). This first aspect will be explained in greater detail in connection with FIGS. 1 to 5:

(23) FIG. 1 shows the feed unit 10 and the setting unit 8 in a completely retracted starting position A. Starting from this starting position A, the feed unit 10 may move into any intermediate position between the starting position A and a setting position S of the setting unit 8. FIG. 2 shows a first intermediate position Z1 and FIG. 5 shows a second intermediate position Z2. At the beginning of processing the workpiece 6, in which in particular a plurality of connecting elements 4 are fastened successively in the course of several setting processes, the feed unit 10 moves first of all from the starting position A shown in FIG. 1, preferably together with the setting unit 8, to the first intermediate position Z1 shown in FIG. 2. In this position, the connecting element 4 is transferred from the feed unit 10 to the setting head 36. For this purpose, the feed punch 52 moves out laterally to convey the connecting element 4 laterally to the setting head 36. After successful transfer, only the setting unit 8 moves to the setting position S, shown in FIG. 4. In this setting position S, the actual setting step takes place for establishing the positive connection of the connecting element 4 with the workpiece 6.

(24) After each setting process, a renewed conveyance of a further connecting element 4 to the setting head 36 is required. Due to the axial adjustment in the feed direction 18, a required travel path x, which the setting unit 8 must cover, is optimized in such a way that it is as short as possible under the given circumstances. As a result, high cycle rates may be achieved.

(25) In the drawings, the workpiece 6 is shown as a simple flat metal sheet. With a simple geometry of this kind, the feed unit 10 would adopt an intermediate position close to the setting position S. Typically, the connecting elements 4, especially for example in the case of motor vehicle parts, must be incorporated into complex workpiece geometries in which accessibility is limited. Typically, the carrier 12 is attached for example to a robot hand, and is moved relative to the workpiece 6. In this movement, contact, for example, of the feed unit 10 with the workpiece 6 should be avoided. The feed unit 10 should therefore be brought to a suitable retracted intermediate position. In the course of workpiece processing 6 (i.e. in the course of the plurality of setting processes), it may be necessary for the feed unit 10 to be moved to different intermediate positions. By way of example, it is shown in FIG. 5 that after the setting process for setting the first connecting element according to FIG. 4, the feed unit 10 moves into the second intermediate position Z2, which is further back. This already has taken place, for example, during the previous setting process. Alternatively, however, a return may occur during the return movement of the setting unit 8.

(26) With regard to a maximum possible cycle rate, it is also generally provided that, for the renewed transfer of an additional connecting element 4 for a subsequent setting process, the feed punch 52 with a connecting element 4 held thereon moves into a pre-position in which the feed punch 52 is partially extended.

(27) After the setting process, the setting unit 8 generally moves back to the intermediate position at which the feed unit 10 is located, receives the next connecting element 4, then moves back to the setting position S and inserts the next connecting element 4 into the workpiece 6.

(28) Overall, this cycle, receive connecting element 4perform setting process at setting position Sreceive next connecting element 4 is repeatedly performed as a work cycle, until for example, the workpiece has been processed, i.e. furnished with the intended number of connecting elements. Within such a work cycle, in the case of a dynamic retraction of the feed unit 10, the step of moving the feed unit to a further intermediate position is additionally provided. In the case of a plurality of such work cycles, a dynamic retraction of the feed unit 10 then takes place in this case.

(29) A second essential aspect relates to the movability of the die punch 26 within the base body 24. This will be explained in greater detail in connection with FIGS. 6 and 7:

(30) The setting process is in particular a multi-stage setting process, composed of a piercing process and a reshaping process for establishing the positive connection of the connecting element 4 with a hole edge of the hole 46 of the workpiece 6.

(31) From the enlarged illustrations in FIGS. 6B, 7B and 7C, the structure of the setting head 36 may once again be seen, with the hold-down 38, the punch sleeve 40 guided therein, and the ejector pin 42 guided therein in turn. These three elements are suitably guided, either coupled together or independently of each other, and adopt different axial positions. As may further be seen from this illustration, the hold-down 38 has the lateral feed opening 50 for the lateral feeding of the connecting element 4.

(32) In the setting process, the workpiece 6 is generally pressed against the holder 20 or the die 22 by means of the hold-down 38. The workpiece 6 therefore comes to rest on an upper side of the die 22, more precisely on an upper side of the base body 24. From the drawings, the structure of the die 22 may be seen further. According to this, the base body 24 has an inner channel 58, within which the die punch 26 is arranged to be adjustable counter to or in the feed direction 18.

(33) The base body 24 also has a lateral opening 60, which may be closed by means of a flap 62. The flap 62 in the exemplary embodiment is a rotary flap that is arranged with one end rotatable about a swivel joint 64. It may be shifted from a position that releases the opening 60 (FIG. 6B) into a position that closes the opening 60 (FIG. 7B), and in the latter case it is oriented substantially vertically. In the open position, the flap rests, in particular, with one end against a wall region of the inner channel 58 opposite the opening 60 and, in particular, is oriented obliquely with respect to the feed direction 18. As a result, it virtually defines a slope or chute (ramp) via which the punched slug 44 may automatically slide out via the lateral opening 60.

(34) Actuation of the flap 62 is carried out automatically by means of the die punch 26.

(35) This die punch is generally arranged so that it may move between a retracted piercing position P1, as shown in FIGS. 6A, 6B, and a front reshaping position P2, as shown in FIGS. 7A, 7B and 7C.

(36) The adjustment takes place by means of the drive mechanism 28. In particular, the drive mechanism 28 has a mechanical linkage 66, which is designed in particular as a toggle mechanism and especially as a toggle lever. The mechanical linkage 66 is actuated in particular by means of the actuating rod 32, wherein the adjusting movement of the actuating rod 32, oriented substantially transversely to the feed direction 18, is converted into a vertical movement in or counter to the feed direction 18.

(37) A particular advantage of this drive mechanism 28 with the mechanical linkage 66 is that the high forces that arise during the reshaping process may be reliably absorbed via the linkage 66 without the second drive 30 being excessively loaded. In the ideal case, the forces are not transmitted to the second drive 30. In this embodiment, therefore, the linkage 66 is locked in place. It is specially a self-locking linkage 66, for example, as a result of the toggle lever design.

(38) The linkage 66 generally acts on a lower foot area of the die punch 26 and is hinged to this foot area. In the exemplary embodiment with the toggle lever a total of three joints are furnished, first to the die punch 26, second to the actuating rod 32 and finally to the carrier 12 on which the toggle lever is supported.

(39) The die punch 26 typically has a conical end on its end face and serves as a support and for reshaping a portion of the connecting element 4 to establish the desired positive connection.

(40) In the exemplary embodiment, a nut is shown as a connecting element 4, which has on its underside a reshaping collar 68, also referred to as a flared collar. This reshaping collar 68 is bent outward during the reshaping process so that a positive rear grip is established with the workpiece 6.

(41) In the exemplary embodiment, in particular a self-piercing nut is furnished that thus initially punches a hole 46 in itself before the reshaping process takes place.

(42) As part of the multi-stage setting process, the hole-punching process is generally carried out first. This is done either by means of the self-piercing connecting element 4 or the punch sleeve 40, which in this case is formed as a piercing sleeve.

(43) In the variant with the self-piercing nut, the nut is pressed against and into the workpiece 6 using the punch sleeve 40 in the first stage of the setting process, so that the reshaping collar 68, which is also configured in this case as a punch collar, penetrates the workpiece 6 and the slug 44 is punched out. In this piercing process, the die punch 26 is arranged in the retracted piercing position P1 shown in FIGS. 6A, 6B. This also applies to the case that the piercing process uses the punch sleeve 40.

(44) There are generally two different variants for the subsequent reshaping process:

(45) According to a first variant, the connecting element 4 is moved against the die punch 26, which in this case is fixed, by means of the setting head 36, so as to reshape the reshaping collar 68. In this first variant, with respect to FIG. 6B, initially at least a slight resetting of the connecting element 4 is required. The punch sleeve 40 thus moves back a section. Next, the die punch 26 moves to the forward reshaping position P2 (FIGS. 7A, 7B) and penetrates into the pre-punched hole 46 with its end face. In the subsequent reshaping step, the connecting element 4 is then pressed against the die punch 26, as shown in FIG. 7C. In this embodiment, the reshaping forces acting in the axial direction are at least largely, or even completely, absorbed by the in particular self-locking mechanical linkage 66, relieving the second drive 30 of these reshaping forces.

(46) In the second variant, a reverse movement process is provided, according to which, starting from the position shown in FIG. 6B, the connecting element remains in the already pierced hole 46 and is held in this position by means of the setting head 36. Subsequently, the die punch 26 moves forward into the reshaping position P2. The reshaping collar 68 then reshaped (radially expanded).

(47) In this second variant as well, the reshaping forces that will be absorbed by the second drive 30 are kept low. This is done in particular due to the special design of the linkage 66, which is generally also supported on the carrier 12 by means of at least an articulated arm, so that at least a part of the reshaping forces is redirected directly into the carrier 12. Finally, a suitable lever is created by the special toggle lever mechanism, so that the force exerted by the second drive is amplified according to the principles of leverage.

(48) The presently described individual advantageous embodiments and different aspects may be combined with one another in any combination, and are not limited to the combinations shown in the drawings.

LIST OF REFERENCE SIGNS

(49) 2 Device 4 Connecting element 6 Workpiece 8 Setting unit 10 Feed unit 12 Carrier 12A Upper curved part 12B Lower curved part 14 First drive 16 Tappet 18 Feed direction 20 Holder 22 Die 24 Base body 26 Die punch 28 Drive mechanism 30 Second drive 32 Actuating rod 34 Linkage 36 Setting head 38 Hold-down 40 Punch sleeve 42 Ejector pin 44 Punched slug 46 Hole 48 Linear guide 50 Lateral feed opening 52 Feed punch 54 Feed tube 56 Control device 58 Inner channel 60 Lateral opening 62 Flap 64 Swivel joint 66 Mechanical linkage 68 Reshaping collar A Starting position P1 Piercing position P2 Reshaping position S Setting position Z Intermediate position Z1 First intermediate position Z2 Second intermediate position x Travel path