A self-piercing die riveter having an indexable die table on the nose of its frame. The die table has a number of dies disposed thereon. The frame defines a first passage and a second passage in communication with and diverging from the first passage. An actuator for indexing the die table is located on the riveter outside of the nose of the frame and is connected to the die table through either shafts or belts disposed within the first and second passages. The die table has a number of detents that cooperate with a locating arm to hinder indexing of the die table and position the dies in-line with the path of a reciprocating punch.

TECHNICAL FIELD

This disclosure relates to self-piercing die riveters, specifically with respect to multiple self-piercing dies that may be indexed in and out of position during use.

BACKGROUND

Self-piercing die riveters have been used to join two or more materials to each other using self-piercing rivets. The materials to be joined are placed between a punch and die of the riveter. The punch contacts the self-piercing rivet at the head and drives the tail towards the die piercing the materials. The self-piercing rivet fully pierces the top sheet material(s) but typically only partially pierces the bottom sheet providing a tight joint. With the influence of the die, the tail end of the rivet flares and interlocks into the bottom sheet forming a low profile button.

Self-piercing rivets are typically fed into position on the riveter from a tape, cassette or spool for continuous production. Self-piercing rivets may be used to join a range of dissimilar materials such as steel, aluminum, plastics, composites and pre-coated or pre-painted materials. Benefits of self-piercing die riveting include low energy demands, no heat, no fumes, no sparks, no waste and very repeatable quality.

Single die riveters have replaceable dies that are slid in and out of a die receiving hole. The die receiving hole is located directly beneath the die and subsequently directly in-line with the punch motion. Having a hole in-line with the punch increases the amount of stress risers and generally requires a need to reinforce the frame of the riveter in that area. Reinforcing the frame near the die requires a larger nose of the frame which limits accessibility of the tool. As well, single die riveters do not have the flexibility to easily change out varying die shapes to allow for a single die riveter to be used with multiple die configurations.

Examples of indexing die riveters having an indexing motor located on the nose of the frame may be found in U.S. Pat. No. 6,964,094 B2 to Kondo and U.S. Pat. No. 7,810,231 B2 to Naitoh. Having indexing motors located on the nose of the frame limits the access of the tool.

The above problem(s) and other problems are addressed by this disclosure as summarized below.

SUMMARY

One aspect of this disclosure is directed to a self-piercing die riveter having a frame that supports a die table. The die table is rotatable on an axis of rotation and has a number of dies disposed there around. The frame defines a first passage extending along an axis of rotation of the die table and a second passage in communication with and diverging from the first passage. An actuator is connected to the die table and is capable of rotating the die table through the first and second passages.

According to another aspect of this disclosure, a die riveter has a die table disposed on the nose of its frame. The die table is rotatable on an axis with a first shaft connected to and extending from the die table along the axis of rotation. A second shaft is coupled to and extends in a diverting direction from the first shaft. An actuator is connected to the second shaft and is capable of rotating the die table through the first and second shafts.

According to a further aspect of this disclosure, a riveter is disclosed that has a die table connected defining a number of detents. A first die is disposed on the die table corresponding to a first detent. A locating arm is connected to the riveter having a free end selectively disposed in the first detent to hinder indexing of the die table and positioning the first die in-line with the path of a reciprocating punch.

The above aspects of this disclosure and other aspects will be explained in greater detail below with reference to the attached drawings.

DETAILED DESCRIPTION

FIG. 1shows a self-piercing die riveter10with a frame12. The frame12may be generally C-shaped defining a head14, a nose16, and a central section18disposed between the head14and the nose16. A punch20is connected to and supported by the head14of the frame12. The punch20is a reciprocating punch and reciprocates along a path22from the head14to the nose16of the frame12. Materials (not shown) may be joined together using the self-piercing die riveter10by placing the materials between the head14and nose16of the frame12within the punch reciprocation path22and a rivet (not shown) may be driven into the materials by the punch20. Materials to be joined may have varying geometries and access points. The shape of the nose16of the frame12is the greatest limiting factor for being able to access and rivet the materials together within the access points.

A die table30is disposed on the frame12and supported by the nose16of the frame12. As illustrated, the die table30has a first die32and a second die34disposed thereon. However, the die table30may have more or less than two dies disposed thereon. Each die on the die table30may have a different geometry. The first die32is positioned in-line with the punch reciprocation path22. The die table30is shown rotatable about an axis of rotation36. The die table30and the dies32,34are shown symmetrically spaced about the axis of rotation36with the axis of rotation36being parallel to the punch reciprocation path22. However, the die table30and/or dies32,34may be asymmetrical in relation to the axis of rotation36. The die table30may also be pivotally coupled to the nose16or indexed linearly longitudinally, transversely, or in any combination, in relation to the nose16.

A first shaft40connects to and extends from the die table30. The first shaft40extends along the axis of rotation36of the die table30such that the die table30rotates about the first shaft40. A first passage42is defined by the nose16of the frame12. The first shaft40is at least partially disposed in the first passage42. The first passage42may be a through hole, as illustrated in the figure, or a blind hole. The first passage42also extends along the axis of rotation36of the die table30. The first passage42extends in a direction offset from the punch reciprocation path22which allows for a lesser reinforced nose16of the frame12as compared to a riveter that has a hole in-line with the punch reciprocation. A hole in-line with the punch reciprocation increases the amount of stress risers and generally requires a need to reinforce the frame of the riveter in the nose resulting in a larger nose and limiting the access of the tool.

A second shaft46is coupled to and extends from the first shaft40in a divergent direction. The second shaft46is at least partially disposed within a second passage48. The second passage48is defined by the frame12and is in communication with and diverges from the first passage42. The second passage48extends from the nose16into and through the central section18of the frame12. The divergent direction of the second shaft46and second passage48from the first shaft40and first passage42, respectively, are illustrated as being generally perpendicular. Generally, perpendicular means angles ranging from 85 to 95 degrees. However, any angle of diversion greater than zero between the shafts40,46and passages42,48may be used so long as the second shaft46and second passage48extend out and away from the nose16of the frame12.

An actuator52is connected to and supported by the central section18of the frame12. Locating the actuator52away from the nose16, as opposed to having an indexing motor located on the nose16of the frame12, decreases the size of the nose16and increases the accessibility of the tool into access points of materials to be joined. The actuator52is connected to the second shaft46. The actuator52rotates the second shaft46, which rotates the first shaft40to rotate the die table30. Alternatively, the die table30may be indexed in a non-rotating manner, such as transversely across the nose16of the frame12or longitudinally in and out from the nose16of the frame12. The actuator52may index the die table30through the first and second passages42,48rotatably, pivotally, linearly longitudinally, linearly transversely, or in any combination, in relation to the nose16of the frame12.

A controller56actuates the actuator52via an actuation signal58. The controller reciprocates the punch20through a reciprocation signal60. In response to a reciprocation signal60from the controller, the punch20drives a self-piercing rivet into the materials to be joined. The self-piercing rivet is then influenced by the first die32and the tail end of the rivet flares and interlocks into the bottom sheet as defined by the first die32. The controller may send an actuation signal58to the actuator52to rotate the die table30positioning the second die34in-line with the punch reciprocation path22. The controller may also subsequently send a reciprocation signal60to the punch20and drive a self-piercing rivet into the materials to be joined with the tail end of the rivet being influenced by the second die34.

The differing geometry of the second die34as compared to the first die32will result in the rivet having a different geometry within the materials to be joined. This may be useful when combining differing types of materials, combining differing thickness of materials, combining a differing number of materials, desiring differing stiffness or strength of joints and/or driving different sized rivets during a continuous manufacturing process. The self-piercing die riveter10may also be used in conjunction with a robotic arm62and the controller56may also control the robotic arm.

FIG. 2shows the second shaft46coupled to the first shaft40by a bevel gear set66. The bevel gear set66comprises a first bevel gear66adisposed on an end of the first shaft40and a second bevel gear66bdisposed an end of the second shaft46. The bevel gears66a,66bmay be separate components connected to the ends of the shafts40,46, or machined directly into the end of the shafts40,46. As illustrated, the bevel gears66a,66bare miter gears with equal numbers of teeth and with axes at right angles; however, the bevel gears66a,66bmay vary in size having a different number of teeth relative to each other and vary in angle between their respective axes. The bevel gears66a,66bare shown as straight bevel gears having straight teeth; however spiral bevel gears having curved teeth for a smoother and more gradual contact may also be used. The first and second shafts40,46may have axes68a,68bthat intersect, and thus the axes of the first and second passages42,48may also be machined into the frame12to intersect. The bevel gear set66may alternatively use hypoid gears in which the axes68a,68bdo not intersect, and thus the first and second passages42,48may be machined into the frame12such that their respective axes do not intersect.

FIG. 3shows the second shaft46coupled to the first shaft40by a worm drive70. The worm drive70comprises a worm gear70a(also known as a worm wheel) disposed on an end of the first shaft40and a screw70b(also known as a worm) disposed on an end of the second shaft46. Alternatively, the worm gear70amay be disposed on the second shaft46and the screw70bmay be disposed on the first shaft40. The worm gear70aand screw70bmay be separate components connected to the ends of the shafts40,46, or machined directly into the end of the shafts40,46. When using the worm drive70, the first and second shafts40,46, axes68a,68bdo not intersect, and thus the first and second passages42,48axes may be machined such that their respective axes do not intersect.

FIG. 4shows the second shaft46coupled to the first shaft40by a face gear set72. The face gear set72comprises a face gear72a(also known as face wheel, crown gear, crown wheel, contrate gear or contrate wheel) disposed on an end of the first shaft40and a pinion72bdisposed on an end of the second shaft46. Alternatively, the face gear72amay be disposed on the second shaft46and the pinion72bmay be disposed on the first shaft40. The face gear72aand pinion72bmay be separate components connected to the ends of the shafts40,46, or machined directly into the end of the shafts40,46. The face gear set72may be configured such that the axes68a,68bof the shafts40,46do or do not intersect, and thus the machining of the passages42,48into the frame12may be done such that the axes of the passages do or do not intersect.

FIG. 5shows the use of a belt74to couple the actuator52to the first shaft40. The belt74may be a flat belt, round belt, or incorporate multi-grooves or ribs. The belt74may also be a chain of connected links. The belt74may be partially disposed in the second passage48of the frame12. A third passage (not shown) may also be in communication with and extend from the first passage42, such that a driving portion74aof the belt74is partially disposed in the second passage48and a returning portion74bof the belt74is partially disposed in the third passage, or vice versa. The actuator52may be multidirectional and the driving portion74amay become the returning portion when the actuator52switches directions. The belt engages a pulley76disposed on the first shaft40. The pulley76may also be a sprocket, cog, or spindle. The pulley76may be a separate component connected to the end of the first shaft40or machined directly into the end of the first shaft40.

FIG. 6shows a mechanism to inhibit/hinder rotation of the die table30and to locate the die table30in position. The die table30defines a first detent80and a second detent82on its peripheral edge84. The first detent80is located opposite the axis of rotation36from the first die32and a second detent82is located opposite the axis of rotation36from the second die34.

A locating arm90has a proximal end92connected to the frame12and a distal end94, or free end, extending from the proximal end92and disposed in the first detent80. The distal end94of the locating arm90is disposed in the first detent80of the die table30to position the first die32in-line with a reciprocating punch20. Each detent80,82corresponds to a respective die32,34and the locating arm90is disposed in a detent80,82to hinder rotation of the die table30and position its respective die32,34in-line with the punch reciprocation path22(seeFIG. 1).

The die table30is capable of being rotated from a first position in which the distal end94of the locating arm90is disposed in the first detent80to a second position in which the distal end94is disposed in the second detent82, positioning the second die34in-line with the reciprocating punch20. The actuator52may be used to rotate the die table30from a first position to a second position. The locating arm90may be fixed to the frame12, in which the distal end94is selectively disposed in and out of the detents80,82through elastic deformation of the locating arm90. The distal end94of the locating arm90may be spherical to provide a ball and socket resistance in which the actuator52must overcome the resistance force to have the spherical end slide out of the first detent80. The spherical end94then slides along the periphery84of the die table30until it springs back into the second detent82. The locating arm90in cooperation with the detents80,82provides for precision alignment of the dies82,84as opposed to relying on the actuator52to align the dies32,34.

The locating arm90may also pivot at the proximal end92to allow the movement of the distal end94in and out of the detents80,82. A spring (not shown) may be used to bias the locating arm90into the detents80,82and/or along the periphery84of the die table30. A locating arm servo96may also be used to pivot the locating arm90. The controller56may send a signal to the locating arm servo96to pivot the locating arm90away from the die table30when the die table30is actuated to rotate.

FIG. 7shows another example of a die table30cooperating with the locating arm90The die table30defines a first detent80corresponding with a first die32, a second detent82corresponding with a second die34, and a third detent100corresponding with a third die102. The locating arm90may be selectively disposed in one of the detents80,82,100to position its corresponding die32,34,102in-line with the punch reciprocation path22of the punch20(seeFIG. 1). The locating arm90may have a manual adjuster104located between the proximal and distal ends92,94to change the length of the locating arm90and provide for calibration of the placement of the dies. A second locating arm servo106may provide linear movement of the locating arm90at the proximal end92to provide for calibration and/or provide for differing location and orientation of detents80,82,100in the die table30.

FIG. 8shows yet another example of a die table30cooperating with a locating arm90. In this illustration, the distal end94of the locating arm90is not disposed in a detent. Rather, the distal end94is adjacent the peripheral edge84of the die table30between the first and second detents80,82, allowing the die table30to rotate about its axis of rotation36as indicated by arrow108. Alternatively, the die table30may have a linear movement as provided by a coupling such as a rack and pinion configuration (not shown). In a linear movement configuration the locating arm90may be disposed in detents to hinder the linear movement of the die table30.

The controller56is capable of positioning the self-piercing die riveter10between materials to be joined utilizing a robotic arm62. The controller may send a reciprocation signal60to the punch20to reciprocate and punch a rivet into the materials to be joined. The locating arm90may hinder the movement of the die table30providing proper alignment of the first die32with the reciprocation path22of the punch20. The controller56may then use the robotic arm62to reposition the riveter10to a different location on the materials to be joined. This different location may desire a different rivet geometry. The controller may then send an actuation signal58to the actuator52to index the die table30to provide a second die34in-line with the reciprocating path22of the punch20. The locating arm90exits the detent80corresponding to the first die82and enters the detent82corresponding with the second die34to hinder the rotation of the die table and align the second die34in-line with the punch reciprocation path22. The controller56may then send another reciprocation signal60to the punch20to reciprocate, resulting in a second rivet being placed into the materials to be joined having a different geometry than the first rivet. The controller56may be programmed to join materials autonomously on a mass-production assembly line. Utilizing innovations as described above increases the flexibility of the tool while maintaining tool access.

While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the disclosed apparatus and method. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the disclosure as claimed. The features of various implementing embodiments may be combined to form further embodiments of the disclosed concepts.