PUNCH RIVETING DEVICE WITH ADVANCED MATRICES

Abstract

Punch riveting device (10), comprising: a frame (12) supporting a die table (30) having a die (32, 34) arranged on it, the frame (12) being C-shaped and formed in one piece, the frame (12) defining a first channel (42) extending along an axis of rotation (36) of the die table (30) and a second channel (48) connecting to and branching off from the first channel (42); and an actuator (52) in conjunction with the matrix table (30) and able to rotate the matrix table (30) via the first and second channels (42, 48).

Description

TECHNICAL AREA

[0001] This disclosure relates to punch riveting devices, specifically with regard to multiple self-punching dies that can be switched in and out of position during use. BACKGROUND

[0002] Self-piercing riveting devices are used to join two or more materials using self-piercing rivets. The materials to be joined are placed between a punch and a die of the riveting device. The punch engages the head of the self-piercing rivet and drives the shank toward the die, piercing the materials. The rivet pierces the upper sheet metal(s) but typically only partially penetrates the lower sheet, creating a tight seal. Under the influence of the die, the end of the rivet shank expands and locks into the lower sheet, forming a low-profile locking head.

[0003] For continuous production, the self-piercing rivets are typically fed to the riveting machine from a tape, cassette, or spool. Self-piercing rivets can be used to join a variety of materials, such as steel, aluminum, plastics, composites, and pre-coated or pre-painted materials. Advantages of self-piercing riveting include low energy consumption, no heat, no fumes, no waste, and highly repeatable quality.

[0004] Single-die self-piercing riveting devices feature interchangeable dies that slide in and out of a die mounting bore. The die mounting bore is located directly beneath the die and thus in the line of the punch movement. The presence of a bore in the punch line leads to increased stress and generally necessitates reinforcement of the riveting device frame in this area. Reinforcing the frame near the die requires a larger frame support, which limits tool accessibility. Furthermore, single-die self-piercing riveting devices are not flexible enough for easy exchange between different die shapes, and therefore a single-die self-piercing riveting device cannot be used with multiple die configurations.

[0005] Examples of self-piercing riveting devices with advancing dies, featuring a switching motor mounted on the base (counterholder) of the frame, can be found in U.S. Patent No. 6964094 B2, granted to Kondo, and U.S. Patent No. 7810231 B2, granted to Naitoh. Mounting switching motors on the frame's counterholder reduces tool accessibility. U.S. Patent No. 2,652,167 A shows a riveting device with a switching motor.

[0006] The present disclosure, as summarized below, solves the above problem(s) as well as other problems. SUMMARY

[0007] One aspect of this disclosure relates to a self-piercing riveting device comprising a frame that supports a die table. The die table is rotatable about an axis of rotation and has a number of dies arranged around it. The frame is C-shaped and formed in one piece. The frame defines a first channel that runs along an axis of rotation of the die table and a second channel that is connected to and branching off from the first channel. An actuator is attached to the die table, which is capable of rotating the die table via the first and second channels.

[0008] According to another aspect of this disclosure, a self-piercing riveting device has a die table arranged at the base of its frame. The die table is rotatable about an axis, and a first shaft is connected to the die table, extending from the die table along the axis of rotation. A second shaft is coupled to the first shaft and extends from the first shaft in a branching direction. An actuator is connected to the second shaft and is capable of rotating the die table about the first and second shafts.

[0009] According to another aspect of this disclosure, a riveting device with an attached die table is disclosed, the die table defining a number of notches. A first die is arranged on the die table and corresponds to a first notch. A locking arm is attached to the riveting device, the locking arm having a free end that is selectively positioned in the first notch to prevent the table from advancing and the first die from being positioned in line with the path of a lifting punch.

[0010] The above aspects of this revelation and other aspects are explained in more detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 shows a schematic side view of a die table on a base part of a frame of a punch riveting device, an actuator arranged at a distance from the base part of the riveting device and the coupling of the actuator to the die table via shafts arranged in channels of the frame. Fig. Figure 2 is a partial side view of a first shaft coupled to a second shaft via a bevel gear set. Fig. Figure 3 is a perspective partial view of a first shaft that is coupled to a second shaft via a worm gear set. Fig. Figure 4 is a perspective partial view of a first shaft, which is coupled to a second shaft via a worm gear set. Fig. Figure 5 is a perspective partial view of a belt coupled to a first shaft. Fig. Figure 6 is a partial top view of a foot part of a frame of a punch riveting device and shows a die table with two dies and a locking arm, the far end of which is arranged in a notch to lock one of the two dies below a punch. Fig. Figure 7 is a partial top view of a foot part of a frame of a punch riveting device and shows a die table with three dies and a locking arm, the far end of which is arranged in a notch to lock one of the three dies below a punch. Fig. Figure 8 is a partial top view of a foot part of a frame of a punch riveting device and shows a die table with four dies and a locking arm, the far end of which is arranged outside a notch while the table rotates. DETAILED DESCRIPTION

[0011] The illustrated embodiments are disclosed with reference to the drawings. However, it should be understood that the disclosed embodiments are intended merely as examples, which can be implemented in various and alternative forms. The figures are not necessarily to scale, and certain features may be exaggerated or understated to show details of particular components. The specific structural and functional details disclosed here are not to be interpreted as limiting, but solely as a representative basis to illustrate to a person skilled in the art the practical realization of the disclosed concepts.

[0012] Fig. Figure 1 shows a self-piercing riveting device 10 with a frame 12. The frame 12 can generally be C-shaped and defines a head 14, a foot 16, and a central body section 18 located between the head 14 and foot 16. A punch 20 is connected to and held by the head 14 of the frame 12. The punch 20 is a reciprocating punch and moves back and forth along the stroke 22 from the head 14 to the foot 16 of the frame 12. Materials (not shown) can be joined using the self-piercing riveting device 10 by placing the materials between the head 14 and foot 16 of the frame 12 in the punch stroke 22, and a rivet (not shown) can be driven into the materials by the punch 20. The materials to be joined can have different geometries and joining points.The shape of the foot section 16 of the frame 12 is the biggest limiting factor for the accessibility and rivetability of the materials within the joining points.

[0013] A die table 30 is arranged on the frame 12 and supported by the base 16 of the frame 12. As shown, the die table 30 has a first die 32 and a second die 34 arranged on it. However, the die table 30 can have more or fewer than two dies arranged on it. Each die on the die table 30 can have a different geometry. The first die 32 is positioned in line with the punch stroke 22. The die table 30 is shown to be rotatable about an axis of rotation 36. The die table 30 and the dies 32 and 34 are shown at a symmetrical distance from the axis of rotation 36, which is parallel to the punch stroke 22. However, the die table 30 and / or the dies 32 and 34 can be arranged asymmetrically with respect to the axis of rotation 36.The matrix table 30 can also be swivelled together with the foot section 16 or switched on in relation to the foot section 16 longitudinally linearly, transversely linearly, or in any combination.

[0014] A first shaft 40 connects to and extends away from the die table 30. The first shaft 40 extends along the axis of rotation 36 of the die table 30, causing the die table 30 to rotate around the first shaft 40. The base 16 of the frame 12 defines a first channel 42. The first shaft 40 is at least partially located within the first channel 42. The first channel 42 can be a through-hole, as shown in the figure, or a blind hole. The first channel 42 also runs along the axis of rotation 36 of the die table 30. The first channel 42 extends in a direction offset from the punch stroke 22, thus allowing for less reinforcement of the base 16 of the frame 12 than in a riveting device with a bore located in the punch stroke line.The presence of a bore located in the punch stroke line leads to further stress increases and generally necessitates reinforcement of the riveting device frame on the counter-holder side, resulting in a larger dimensioned base and a tool with limited accessibility.

[0015] A second shaft 46 is coupled to the first shaft 40 and extends away from the first shaft in a branching direction. The second shaft 46 is at least partially arranged in a second channel 48. The second channel 48 is defined by the frame 12, is connected to the first channel 42, and branches off from it. The second channel 48 runs from the base 16 into and through the body section 18 of the frame 12. The direction of the second shaft 46 and the second channel 48 branching off from the first shaft 40 and the first channel 42 is generally shown as perpendicular. "Generally perpendicular" means an angle in the range of 85 to 95 degrees. However, any branching angle greater than zero can be used between the shafts 40, 46 and channels 42, 48, as long as the second shaft 46 and the second channel 48 extend out of and away from the base 16 of the frame 12.

[0016] An actuator 52 is connected to and supported by the body section 18 of the frame 12. Relocating the actuator 52 from the base 16, as opposed to a switching motor located on the base 16 of the frame 12, reduces the size of the base 16 and increases the accessibility of the tool to the joining points of the materials to be joined. The actuator 52 is coupled to the second shaft 46. To rotate the die table 30, the actuator 52 rotates the second shaft 46, which in turn rotates the first shaft 40. Alternatively, the matrix table 30 can be advanced in a non-rotating manner, such as across the foot section 16 of frame 12 or longitudinally in and out of the foot section 16 of frame 12. The actuator 52 can advance the matrix table 30 via the first and second channels 42, 48 in a rotatable, swiveling, longitudinally linear, transversely linear, or any combination thereof, relative to the foot section 16 of frame 12.

[0017] A control unit 56 actuates the actuator 52 via a control signal 58. The control unit moves the punch 20 back and forth via a stroke signal 60. Upon receiving a stroke signal 60 from the control unit, the punch 20 drives a self-piercing rivet into the materials to be joined. The self-piercing rivet is then actuated by the first die 32, and the end of the rivet shank expands and locks into the lower sheet metal, as specified by the first die 32. The control unit can send a control signal 58 to the actuator 52 to rotate the die table 30 and position the second die 34 in line with the punch stroke 22. The control unit can then also send a stroke signal 60 to the punch 20 and drive a self-piercing rivet into the materials to be joined, with the end of the rivet shank being actuated by the second die 34.

[0018] The geometry of the second die 34, which differs from that of the first die 32, results in the rivet having a different geometry in the materials being joined. This can be useful when combining different types of materials, different material thicknesses, different numbers of materials, when different stiffness or strength of the joints is desired, and / or when rivets of different dimensions are set in a continuous manufacturing process. The self-piercing riveting device 10 can also be used in conjunction with a robot arm 62, and the control unit 56 can also control the robot arm.

[0019] Fig. Figure 2 shows the second shaft 46, which is coupled to the first shaft 40 via a bevel gear set 66. The bevel gear set 66 comprises a first bevel gear 66a, located at one end of the first shaft 40, and a second bevel gear 66b, located at one end of the second shaft 46. The bevel gears 66a and 66b can be separate components connected to the ends of the shafts 40 and 46, or they can be milled directly into the ends of the shafts 40 and 46. The bevel gears 66a and 66b shown are right-angle gears with the same number of teeth and perpendicular axes; however, the bevel gears 66a and 66b can be of different sizes, have different numbers of teeth, and have different shaft angles. The bevel gears 66a and 66b are shown as spur bevel gears. However, spiral bevel gears with arc teeth can be used for a smoother and more gradual contact.The first shaft 40 and the second shaft 46 can have axes 68a, 68b that intersect each other, and thus the axes of the first and second channels 42, 48 can also be machined into the frame 12 with their axes intersecting. Alternatively, the bevel gear set 66 can use hypoid gears in which the axes 68a, 68b do not intersect, and thus the first channel 42 and the second channel 48 can be machined into the frame 12 such that their respective axes do not intersect.

[0020] Fig. Figure 3 shows the second shaft 46, which is coupled to the first shaft 40 via a worm gear 70. The worm gear 70 comprises a worm wheel 70a, located at one end of the first shaft 40, and a worm shaft 70b (also referred to as the worm) located at one end of the second shaft 46. Alternatively, the worm wheel 70a can be located on the second shaft 46 and the worm 70b on the first shaft 40. The worm wheel 70a and worm 70b can be separate components connected to the ends of the shafts 40 and 46, respectively, or they can be milled directly into the ends of the shafts 40 and 46. When using worm gear 70, first and second shaft 40, 46, the axes 68a, 68b do not intersect each other, and thus the axes of the first and second channel 42, 48 can be worked in such a way that their respective axes do not intersect each other.

[0021] Fig. Figure 4 shows the second shaft 46, which is coupled to the first shaft 40 via a face gear set 72. The face gear set 72 comprises a face gear 72a (also referred to as a crown gear or spur gear) located at one end of the first shaft 40, and a pinion 72b located at one end of the second shaft 46. Alternatively, the face gear 72a can be located on the second shaft 46 and the pinion 72b on the first shaft 40. The face gear 72a and pinion 72b can be separate components connected to the ends of the shafts 40 and 46, respectively, or they can be milled directly into the ends of the shafts 40 and 46. The planar gear set 72 can be configured so that the axes 68a, 68b of the shafts 40, 46 intersect or do not intersect, and thus the machining of the channels 42, 48 into frame 12 can be carried out such that the axes of the channels intersect or do not intersect.

[0022] Fig. Figure 5 shows the use of a belt 74 for coupling the actuator 52 to the first shaft 40. The belt 74 can be a flat belt, a round belt, or it can have multiple grooves or ribs. The belt 74 can also be a chain. The belt 74 can be partially arranged in the second channel 48 of frame 12. A third channel (not shown) can also be connected to and extend from the first channel 42, such that a drive leg 74a of the belt 74 is partially arranged in the second channel 48 and a return leg 74b of the belt 74 is partially arranged in the third channel, or vice versa. The actuator 52 can be multidirectional, and the drive leg 74a can become the return leg when the actuator 52 changes direction. The belt wraps around a pulley 76 located on the first shaft 40. The pulley 76 can also be a sprocket, a gear, or a spindle.The disc 76 can be a separate component connected to the end of the first shaft 40, or it can be incorporated directly into the end of the first shaft 40.

[0023] Fig. Figure 6 shows a mechanism for inhibiting / preventing the rotational movement of the die table 30 and for locking the position of the die table 30. The die table 30 defines a first notch 80 and a second notch 82 in its circumferential edge 84. The first notch 80 is located opposite the axis of rotation 36 from the first die 32, and a second notch 82 is located opposite the axis of rotation 36 from the second die 34.

[0024] A locking arm 90 has a near end 92, which is connected to the frame 12, and a far end 94, or free end, which extends from the near end 92 and is located in the first notch 80. The far end 94 of the locking arm 90 is located in the first notch 80 of the die table 30 to align the first die 32 in line with a stroke punch 20. Each notch 80, 82 corresponds to a corresponding die 32, 34, and the locking arm 90 is located in a notch 80, 82 to restrain the rotation of the die table 30 and to align its corresponding die 32, 34 in line with the stroke path 22 (see Fig. 1).

[0025] The die table 30 can be rotated from a first position, in which the far end 94 of the locking arm 90 is positioned in the first notch 80, to a second position, in which the far end 94 is positioned in the second notch 82, thus positioning the second die 34 in line with the lifting punch 20. The actuator 52 can be used to rotate the table 30 from a first position to a second position. The locking arm 90 can be attached to the frame 12, where the far end 94 can be selectively positioned in and outside the notches 80 and 82 by elastic deformation of the locking arm 90. The far end 94 of the locking arm 90 can be spherical to provide a ball-and-pin resistance, whereby the actuator 52 must overcome the resistance force to push the spherical end out of the first notch 80.The spherical end 94 then slides along the circumference 84 of the matrix table 30 until it springs back into the second notch 82. The locking arm 90, in conjunction with the notches 80 and 82, ensures precise alignment of the matrices 32 and 34, in contrast to alignment of the matrices 32 and 34 using actuator 52.

[0026] The indexing arm 90 can also pivot about a pin at the near end 92 to allow the far end 94 to move in and out of the notches 80, 82. A spring (not shown) can be used to move the indexing arm 90 into the notches 80, 82 and / or along the circumference 84 of the die table 30. An indexing arm servo drive 96 can also be used for the pivoting movement of the indexing arm 90. The control unit 56 can send a signal to the indexing arm servo drive 96 to pivot the indexing arm 90 away from the die table 30 when the die table 30 is energized to rotate.

[0027] Fig. Figure 7 shows another example of a die table 30 in conjunction with the indexing arm 90. The die table 30 defines a first notch 80, corresponding to a first die 32, a second notch 82, corresponding to a second die 34, and a third notch 100, corresponding to a third die 102. The indexing arm 90 can be selectively moved into one of the notches 80, 82, or 100 to align its corresponding die 32, 34, or 102 in line with the punch stroke 22 of the punch 20 (see Figure 7). Fig. 1) The indexing arm 90 can have a manual adjustment 104 located between the near and far ends 92, 94 to adjust the length of the indexing arm 90 and to calibrate the placement of the dies. A second indexing arm servo drive 106 can provide linear movement of the indexing arm 90 at the near end 92 to calibrate and / or adjust the position and orientation of the notches 80, 82, 100 in the die table 30.

[0028] Fig.Figure 8 shows another example of a die table 30 interacting with a locking arm 90. In this illustration, the far end 94 of the locking arm 90 is not arranged in a notch. Instead, the far end 94 rests between the first and second notches 80, 82 on the circumferential edge 84 of the die table 30 and allows the die table 30 to rotate about its axis of rotation 36, as indicated by arrow 108. Alternatively, the die table 30 can exhibit linear motion, as provided by a coupling such as a rack and pinion configuration (not shown). In a linear motion configuration, the locking arm 90 can be arranged in notches to restrain the linear motion of the die table 30.

[0029] The control unit 56 is able to position the self-piercing riveting device 10 between the materials to be joined using a robot arm 62. The control unit can send a stroke signal 60 to the punch 20, causing it to perform a stroke movement and press a rivet into the materials to be joined. The locking arm 90 can lock the movement of the die table 30 and ensure the correct alignment of the first die 32 with the stroke 22 of the punch 20. The control unit 56 can then use the robot arm 62 to reposition the riveting device 10 to a different location on the materials to be joined. A different rivet geometry may be required at this other location. The control unit can then send a positioning signal 58 to the actuator 52 to advance the die table 30 and provide a second die 34 in line with the stroke 22 of the punch 20.The locking arm 90 exits the notch 80, corresponding to the first die 32, and moves into the notch 82, corresponding to the second die 34, to lock the table's rotation and align the second die 34 with the punch stroke 22. The control unit 56 can then send another stroke signal 60 to the punch 20, causing it to perform a stroke movement. This results in a second rivet, with a different geometry than the first, being placed into the materials to be joined. The control unit 56 can be programmed to autonomously join materials in a mass production assembly line. The use of innovations as described above increases the tool's flexibility while maintaining its accessibility.

[0030] Exemplary embodiments are described above, but it is not intended that these embodiments describe all possible forms of the disclosed device and method. The words used in this document are not limiting but rather descriptive, and it is assumed that various modifications can be made without deviating from the essence and scope of the disclosure as claimed. The features of different embodiments can be combined to develop further realizations of the disclosed concepts.

Claims

[1] Punch riveting device (10), comprising: a frame (12) supporting a die table (30) having a die (32, 34) arranged on it, the frame (12) being C-shaped and formed in one piece, the frame (12) defining a first channel (42) extending along an axis of rotation (36) of the die table (30) and a second channel (48) connecting to and branching off from the first channel (42); and an actuator (52) in conjunction with the matrix table (30) and able to rotate the matrix table (30) via the first and second channels (42, 48). [2] Punch riveting device (10) according to claim 1, wherein the first channel (42) extends in a direction offset to a stroke (22) of a punch (20) and the second channel (48) extends substantially perpendicular to the first channel (42). [3] Punch riveting device (10) according to claim 1, further comprising a first shaft (40) which is connected to the die table (30) and is at least partially arranged in the first channel (42). [4] Punch riveting device (10) according to claim 3, further comprising a second shaft (46) which couples the actuator (52) to the first shaft (40) and is arranged at least partially in the second channel (48). [5] Punch riveting device (10) according to claim 4, wherein the second shaft (46) is coupled to the first shaft (40) via a bevel gear set (66), angle gear set, worm gear (70) and / or face gear set (72). [6] Punch riveting device (10) according to claim 3, further comprising a belt (72) which is at least partially arranged in the second channel (48) and couples the actuator (52) to the first shaft (40). [7] Punch riveting device (10) according to claim 1, further comprising a locking arm (90) having a near end (92) connected to the frame (12) and a far end (94) extending away from the near end (92), wherein the die table (30) defines a notch (80, 82) and the far end (94) of the locking arm (90) is selectively arranged in the notch (80, 82) of the die table (30) to position the die (32, 34) in line with a punch (20). [8] Punch riveting device (10) according to claim 7, further comprising at least one additional die (32, 34) arranged on the die table (30), wherein the die table (30) defines at least one recess (80, 82) corresponding to the respective at least one additional die (32, 34), and the die table (30) is able to be rotated such that the far end (94) of the locking arm (90) is selectively arranged in the at least one recess (80, 82) to position the corresponding die (32, 34) of the at least one additional die (32, 34) in line with the punch (20). [9] Punch riveting device (10) according to claim 7, wherein the notch (80, 82) is located opposite the axis of rotation (36) at the circumferential edge (84) of the die table (30). [10] Punch riveting device (10) according to claim 7, wherein the locking arm (90) is adjustable. [11] Punch riveting device (10) according to claim 7, wherein the near end (92) of the locking arm (90) is attached to the frame (12) and the far end (94) of the locking arm (90) is selectively arranged in and outside the notch (80, 82) by elastic deformation of the locking arm (90). [12] Punch riveting device (10) according to claim 7, further comprising a control unit (56) in conjunction with the die table (30), actuator (52) and locking arm (90), which is able to rotate the die table (30) to switch from the die (32, 34) positioned in line (22) with the punch (20) to the at least one additional die (32, 34) positioned in line with the punch (20).

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