POSITION SENSING A LOCATION PIN IN A WELDING ELECTRODE

Abstract

An apparatus includes a housing, a pin, a mechanism, and a sensor. The housing is configured to receive a weld head. The pin is configured to move linearly relative to said housing. The mechanism is configured to convert a position of said pin into a displacement. The sensor is configured to generate a value representative of said position of said pin based on said displacement.

Description

FIELD OF THE INVENTION

The present invention relates to resistance welding generally and, more particularly, to a method and/or architecture for position sensing a location pin in a welding electrode.

BACKGROUND OF THE INVENTION

Detecting a proper orientation of a weld fastener before applying a welding current is an issue in conventional welding assemblies. A mis-orientated or incorrect weld fastener can cause destruction of the welding electrodes, destruction of the weld fastener and destruction of the weld tooling. Any such destruction causes delays in production and incurs an expense in replacing the destroyed parts. Welding with the wrong fastener, or welding with the correct fastener but in the wrong orientation, results in rejections of the welded fasteners, failures in the welded fasteners in service and rework to replace the mis-welded fasteners.

It would be desirable to implement position sensing a location pin in a welding electrode.

SUMMARY OF THE INVENTION

The present invention concerns an apparatus including a housing, a pin, a mechanism and a sensor. The housing is configured to receive a weld head. The pin is configured to move linearly relative to said housing. The mechanism is configured to convert a position of said pin into a displacement. The sensor is configured to generate a value representative of said position of said pin based on said displacement.

The objects, features and advantages of the present invention include providing position sensing a location pin in a welding electrode that may (i) monitor an orientation of a weld part, (ii) monitor a presence/absence of the weld part, (iii) sense a position of a location pin in a way immune to electromagnetic fields generated during the welding process, (iv) incorporate inexpensive monitoring components, (v) replicate a height of conventional electrodes without the position sensing, (vi) incorporate a limit switch, (vii) incorporate a voltage detector, (viii) incorporate a visual indicator, (ix) incorporate an electrical angle sensor, (x) incorporate a mechanical angle sensor, (xi) incorporate an optical angle sensor, (xii) incorporate a pneumatic angle sensor, (xiii) provide ease of maintenance and/or (xiv) easily adapt to existing weld assemblies.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects, features and advantages of the present invention will be apparent from the following detailed description and the appended claims and drawings in which:

FIG. 1 is a cross-sectional exposed view of an apparatus in accordance with a preferred embodiment of the present invention;

FIG. 2 is another cross-sectional view of the apparatus;

FIG. 3 is a cross-sectional view of another apparatus;

FIG. 4 is a diagram of an electro-mechanical angle sensor;

FIG. 5 is a cross-sectional view of an optical angle sensor;

FIG. 6 is a detailed diagram of the optical angle sensor;

FIG. 7 is a diagram of a pneumatic angle sensor;

FIG. 8 is a cross-sectional view of another apparatus;

FIG. 9 is a cross-sectional view of a load position;

FIG. 10 is a cross-sectional view before welding;

FIG. 11 is a cross-sectional view after the welding;

FIG. 12 is a cross-sectional view with an upside down fastener;

FIG. 13 is a perspective view of another apparatus;

FIG. 14 is a cross-sectional view of still another apparatus;

FIG. 15 is a cross-sectional view of an apparatus with a weld stud in the load position;

FIG. 16 is a cross-sectional view of the apparatus and the weld stud before welding;

FIG. 17 is a cross-sectional view of another apparatus with another weld stud before welding;

FIG. 18 is a cross-sectional view of still another apparatus with still another fastener in the load position; and

FIG. 19 is a cross-sectional view of yet another apparatus with yet another weld stud in the load position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Various embodiments of the present invention may provide one or more monitoring techniques of a position, an orientation and/or an absence of a part to be welded before welding begins. The monitoring techniques are generally immune to electromagnetic fields generated by a welding current applied by a welding electrode to the part to be welded. A welding electrode incorporating the monitoring techniques may have a height matching or similar to that of existing welding electrodes without the monitoring techniques. Where incorporated into one of a pair of welding electrodes (e.g., a lower and/or stationary electrode), the welding electrodes may be easily adapted to existing welding machines and provide ease of maintenance.

A location pin of the welding electrode may move linearly in a housing to determine an orientation and/or absence of the part to be welded. A position of the location pin may be monitored (or sensed) by converting the position of the location pin into an angular position and measuring the angular position. The monitoring techniques may incorporate low-cost sensors. The sensors generally include, but are not limited to, a limit switch, a voltage detector, a visual indicator, an electrical angle sensor, a mechanical angle sensor, an optical angle sensor and/or a pneumatic angle sensor. Other sensors that measure a rotation of a shaft may be implemented to meet the criteria of a particular design application.

Referring to FIG. 1, a cross-sectional exposed view of an example implementation of an apparatus 100 is shown in accordance with a preferred embodiment of the present invention. The apparatus (or system) 100 may implement a welding electrode. The apparatus 100 may be configured to weld a fastener (or part) 90 to an object (or component) 92. The welding may be achieved by electrical resistance welding.

The apparatus 100 generally comprises a housing (or assembly) 102, a location pin (or assembly) 104, a cavity (or bore) 106, a port (or bore) 108, a spring (or assembly) 110, a rotary lever (or arm) 112, a shaft (or rod) 114, a weld head (or electrode) 116, a rotary indicator (see FIG. 2) 118 and an encoder (or monitor) 120. In operation, the fastener 90 and the object 92 are brought into contact with the weld head 116 at an end of the housing 102. The location pin 104 is generally received in an opening of the fastener 90 and an opening of the object 92. A linear distance that the location pin 104 travels into the opening of the fastener 90 generally indicates if the fastener 90 is selectively (or alternatively) in a proper orientation, an improper orientation (e.g., upside down), missing and/or is an incorrect part.

The location pin 104 may be pushed (or biased) toward the fastener 90 by air pressure created in the cavity 106 through the port 108 and/or by the spring 110. As the assembly 100 and the fastener 90/object 92 are brought together, the location pin 104 generally contacts the fastener 90. A force created between the fastener 90 and the location pin 104 may cause the location pin 104 to move into the housing 102 and compress the spring 110. The movement may stop when the weld head 116 contacts the object 92. The weld head 116 generally conveys the welding current to the object 92.

The rotary lever 112 is generally disposed between the location pin 104 and the spring 110. The linear motion of the location pin 104 may be converted (or translated) into an angular motion of the rotary lever 112 about the shaft 114. A center of rotation of the shaft 114 is generally offset from a centerline of the location pin 104 (e.g., offset to the left in the figure). The sensor 120 may measure an angle (e.g., an absolute angle or a relative angle) of the shaft 114 in reference to the housing 102. An angle value of the measured angle of the shaft 114 is generally proportional to a distance (e.g., Z) traveled by the location pin 104 in reference to the housing 102 while the fastener 90/the object 92 are moved from an initially-contacting (or load) position to a welding position. The distance (or position) Z that the location pin 104 travels may be used to determine if the welding process may be allowed (e.g., a proper fastener 90 in a proper orientation) or should be denied (e.g., wrong fastener, missing fastener, incorrect orientation, and/or any other error).

Referring to FIG. 2, another cross-sectional view of the apparatus 100 is shown. A combination of the rotary indicator 118 and the encoder 120 may form a sensor (or detector) 122. The sensor 122 may be in communication with a circuit 124 via one or more electrical signals.

The rotary indicator 118 may be coupled to the shaft 114. In various embodiments, the coupling may be a direct connection or an indirect connection between the rotary indicator 118 and the shaft 114. The coupling generally causes the rotation of the shaft 114 to be conveyed to the rotary indicator 118. The angular position of the rotary indicator 118 relative to the housing 102 may be identical to the angular position of the shaft 114. The encoder 120 may be mounted on the housing 102 in alignment with the rotary indicator 118.

In some embodiments, the rotary indicator 118 may be implemented as a positioning element. For example, the rotary indicator 118 may be a positioning element (e.g., part number P1-Ri-SR14, available from Turck Inc., Minneapolis, Minnesota) for inductive angle sensors. In some embodiments, the encoder 120 may be implemented as an inductive angle sensor (e.g., part number Ri30-P2-QR14, available from Truck Inc.) In various embodiments, the rotary indicator 118 and the encoder 120 may be arranged in a non-contact configuration.

The sensor 122 generally provides an oscillator circuit coupling between a transducer in the encoder 120 and a sensor in the rotary indicator 118. The oscillator circuit coupling may be immune to electromagnetic interference, such as the electromagnetic fields generated during the welding process. The sensor 122 may generate an analog electrical signal proportional to an angle of the rotary indicator 118 relative to the encoder 120. The analog electrical signal may be digitized in the circuit 124 to a finite resolution (e.g., 12 bits). At 12-bits resolution, the circuit 124 may monitor an angle value of the shaft 114 to a few hundredths of a degree (e.g., <0.09 degrees). Additional details of the sensor 122 may be found in datasheet “Inductive Angle Sensor With Analog Output”, Ri30P2-QR14-LiU5X2-0,3-RS4, by Turck Inc., which is hereby incorporated by reference in its entirety. Other types of electrical angle sensors may be implemented to meet the criteria of a particular design application.

The circuit 124 may implement a detector circuit. The circuit 124 is generally operational to measure the electrical signal generated by the sensor 122. Based on the measurement, the circuit 124 may provide status of the location pin 104 position to a weld control circuit (not shown). The weld control circuit generally controls the welding current applied to the weld head 116. The status may include, but is not limited to, a proper orientation of the fastener 90, an incorrect orientation of the fastener 90, the fastener 90 is missing and/or an incorrect fastener is detected. For example, the angular position measured by the sensor 122 may be translated in the circuit 124 to a linear position of the location pin 104. Where the location pin 104 is in a “correct orientation” position range, the circuit 124 may signal the weld control circuit that the fastener 90/object 92 are ready to weld. Where the location pin 104 is in an “incorrect orientation” position range, the circuit 124 may signal the weld control circuit that the fastener 90 is present and in the wrong orientation. Where the location pin 104 is in one or more possible “wrong part” position ranges, the circuit 124 may signal the weld control circuit that an incorrect fastener is loaded. Where the location pin 104 is in a “missing” position range, the circuit 124 may signal the weld control circuit that the fastener 90 and/or object 92 is missing. Other position ranges of the location pin 104 may be implemented to meet the design criteria of particular applications.

Referring to FIG. 3, a cross-sectional view of an example implementation of an apparatus 100a is shown. The apparatus 100a may be a variation of the apparatus 100. The apparatus 100a generally includes the housing 102, a spring (or assembly) 110a, a shaft (or rod) 114a and a sensor (or detector) 122a. The sensor 122a may be in electrical communication with a circuit 124a. The spring 110a (e.g., a rotary spring) may be a variation of the spring 110. The shaft 114a may be a variation of the shaft 114. The sensor 122a may be a variation of the sensor 122. The circuit 124a may be a variation of the circuit 124. Other elements of the apparatus 100 may be included in the apparatus 100a.

The sensor 122a may implement an electrical angle sensor. The sensor 122a may be operational to convert the angular position of the shaft 114a into an angle value. The angle value may be presented in one or more electrical signals to the circuit 124a. The shaft 114a may be longer than the shaft 114. The shaft 114a may extend outside the housing 102 and into the sensor 122a. The circuit 124a may be operational to measure the angle value measured by the sensor 122a. The circuit 124a may be operational to provide the status indications to the weld control circuit based on the measured angle value, similar to the circuit 124.

Referring to FIG. 4, a diagram of an example implementation of an electro-mechanical angle sensor 122b is shown. The sensor 122b may be a variation of the sensors 122 and/or 122a. The sensor 122b may be mounted to the housing 102. The sensor 122b may be in electrical communication with a circuit 124b. The circuit 124b may be a variation of the circuits 124 and/or 124a.

The sensor 122b generally comprises a wheel (or disk) 130, an arm (or lever) 132, a detent 134 in the wheel 130, a contact switch (or relay) 136 and a latch (or limit switch) 138. The wheel 130 may be coupled, indirectly connected, or directly connected to the shaft 114a. The circuit 124b may be operational to provide the status indications to the weld control circuit based on the measured angle value, similar to the circuit 124.

As the location pin 104 is pushed into the housing 102, the wheel 130 may be turned by the shaft 114a. In some embodiments, the arm 132 may be designed to press the contact switch 136 if the distance traveled by the location pin 104 indicates a present and properly oriented fastener 90. The circuit 124b may electrically sense a change in the contact switch 136 from unpressed to pressed. While the contact switch 136 is pressed, the circuit 124b may communicate to the weld control circuit that the fastener 90, the object 92 and the weld head 116 combination are in a correct orientation to be welded. While the contact switch 136 is unpressed, the circuit 124b may communicate to the weld control circuit that at least one of the fastener 90, the object 92 and/or the weld head 116 combination is not ready for the weld process to take place.

A length from the center of rotation of the shaft 114a to an outer end of the arm 132 may be greater than a length of the lever 112 (FIG. 1). The longer length of the arm 132 may provide a mechanical amplification of the distance Z that the location pin 104 is moved. A small movement of the location pin 104 may be translated into a larger linear movement of the contact switch 136 allowing for a more precise sensing of where the location pin 104 is positioned.

In other embodiments, the detent 134 and the latch 138 may be designed such that the detent 134 and the latch 138 are aligned with each other when the fastener 90, the object 92 and the weld head 116 combination are in a correct orientation to be welded. The circuit 124b may be configured to electrically monitor the latch 138 to detect an aligned condition and a not align condition between the detent 134 and the latch 138. When aligned, the circuit 124b may communicate to the weld control circuit that the welding process may take place. The circuit 124b may be configured to treat a non-aligned condition between the detent 134 and the latch 138 as an indication that at least one of the fastener 90, the object 92 and/or the weld head 116 combination is not ready for the weld process to take place.

Referring to FIG. 5, a cross-sectional view of an example implementation of an optical angle sensor 122c is shown. The sensor 122c may be a variation of the sensors 122, 122a and/or 122b. The sensor 122c may be mounted to the housing 102. The sensor 122c may be in electrical communication with a circuit 124c. The circuit 124c may be a variation of the circuits 124, 124a and/or 124b.

The sensor 122c may be directly or indirectly coupled or connected to the shaft 114a. An electrical signal generated by the sensor 122c may be proportional to an angle (absolute or relative) of the shaft 114a. The electrical signal generated by the sensor 122c may be received by the circuit 124c. The circuit 124c may examine the signal to determine if the fastener 90, the object 92 and the weld head 116 are properly aligned for the welding process to begin. Based on the angle value received in the electrical signal, the circuit 124c may determine that one or more of the fastener 90, the object 92 and/or the weld head 116 are not ready for welding. The circuit 124c may report the ready/not ready/missing part/wrong part determination to the weld control circuit. The circuit 124c may be operational to provide the status indications to the weld control circuit based on the measured angle value, similar to the circuit 124.

Referring to FIG. 6, a detailed diagram of an example implementation of the sensor 122c is shown. The sensor 122c generally comprises an extension (or wheel) 140, a shutter (or block) 142, a light source 144 that shines a light beam 146 toward a light sensor 150. The shutter 142 may be aligned along an outer edge of the extension 140 to prevent the light beam 146 from reaching the light sensor 150 at some angles (as shown). The shutter 142 may permit the light beam 146 to reach the light sensor 150 along a path 148 at other angles. The extension 140 may be coupled (or indirectly connected or directly connected) to the shaft 114a.

The circuit 124c may receive an electrical signal from the light sensor 150. The electrical signal may indicate that the light beam 146 has either reached the sensor 150 or is blocked by the shutter 142. Before the location pin 104 engages the fastener 90, the light beam 146 may reach the light sensor 150. The circuit 124c may monitor the light sensor 150 and communicate to the weld control circuit that the welding process should be inhibited. Where the location pin 104, the fastener 90 and the object 92 are present and properly aligned, the extension 140 may rotate the shutter 142 into the light beam 146 (as shown) to prevent the light beam 146 from reaching the light sensor 150. The circuit 124c may sense the change in the electrical signal generated by the now-dark light sensor 150 and communicate to the weld control circuit that the welding process may proceed. If the location pin 104 travels too far, the light beam 146 may become unblocked by the shutter 142. The light sensor 150 may convey the illumination to the circuit 124c. The circuit 124c may communicate to the weld control circuit that something is wrong with the faster 90, the object 92 and/or the location pin 104. The weld control circuit may inhibit the welding process in such situations. In various embodiments, the shutter 142 may be configured such that the light bean 146 reaches the light sensor 150 only when the faster 90, the object 92 and the location pin 104 are properly positioned for welding, and block the light beam 146 otherwise.

A length from the center of rotation of the shaft 114a to a point on the shutter 142 that engages the light beam 146 may be greater than a length of the lever 112 (FIG. 1). The longer length may provide a mechanical amplification of the distance Z that the location pin 104 is moved. A small movement of the location pin 104 may be translated into a larger angular movement of the shutter 142 allowing for a more precise sensing of where the location pin 104 is positioned.

The extension 140 may include markings 152. The markings 152 may provide a visual indication of the position of the location pin 104 relative to the housing 102. The visual indication may be used by an operator of the welding assembly to verify that the fastener 90, the object 92 and the weld head 116 are ready or not ready for the welding process to begin.

Referring to FIG. 7, a diagram of an example implementation of a pneumatic angle sensor 122d is shown. The sensor 122d may be a variation of the sensors 122, 122a, 122b and/or 122c. The sensor 122d may be mounted to the housing 102. The sensor 122d may be in electrical communication with a circuit 124d. The circuit 124d may be a variation of the circuits 124, 124a, 124b and/or 124c.

The sensor 122d generally comprises a wheel (or disk) 160, a tube (or bore) 162 through the wheel 160, an input tube (or pipe) 164, an output tube (or pipe) 166 and a pressure sensor 168. An open end of the input tube 164 may receive a pressurized fluid or gas. The pressure sensor 168 may generate a pressure value proportional to a pressure in the output tube 166. The pressure value may be conveyed from the pressure sensor 168 to the circuit 124d in an electrical signal. The circuit 124d may be operational to provide the status indications to the weld control circuit based on the measured pressure value, similar to the circuit 124.

Before the location pin 104 engages the fastener 90, the tube 162 may block the pressure in the input tube 164 from reaching the pressure sensor 168 via the output tube 166. The circuit 124d may monitor the pressure sensor 168 and communicate to the weld control circuit that the welding process should be inhibited. Where the location pin 104, the fastener 90 and the object 92 are present and properly aligned, the wheel 160 may rotate the tube 162 into alignment with the input tube 164 and the output tube 166. The rotation effectively opens a valve formed by the wheel 160 and the tubes 162, 164 and 166. The circuit 124d may sense the change in the pressure value in the electrical signal generated by the pressure sensor 168 and communicate to the weld control circuit that the welding process may proceed. If the location pin 104 travels too far, the tube 162 may rotate out of alignment with the tubes 164 and 166. The pressure sensor 168 may convey the reduced pressure to the circuit 124d. The circuit 124d may communicate to the weld control circuit that something is wrong with the faster 90, the object 92 and/or the location pin 104. The weld control circuit may inhibit the welding process in such situations.

Referring to FIG. 8, a cross-sectional view of an example implementation of an apparatus 100b is shown. The apparatus 100b may be a variation of the apparatus 100 and/or the apparatus 100a. The apparatus 100b may be used to weld a weld stud (or part) 90a to the object 92. To account for different geometries between the weld stud 90a and the fastener 90, the apparatus 100b may include a push pin 104a in place of the location pin 104. Operation of the apparatus 100b may be similar to that of the apparatus 100 and/or the apparatus 100a. Other elements of the apparatus 100 and/or the apparatus 100a may be included in the apparatus 100b.

Referring to FIG. 9, a cross-sectional view of the fastener 90 in a load position is shown. In the load position, the location pin 104 may be pushed (or biased) to a maximum distance out of the housing 102. The fastener 90, if present, may be in contact with the location pin 104 but does not apply any force to the location pin 104. If the fastener 90 is missing, the location pin 104 may also be pushed (or biased) to the maximum distance out of the housing 102. In the load position, the sensor 122 (or 122a, 122b, 122c or 122d) may be monitored by the respective circuit 124 (or 124a, 124b, 124c or 124d). The circuit 124 may report to the weld control circuit that the welding process should be inhibited.

Referring to FIG. 10, a cross-sectional view before welding is shown. The fastener 90 may be in contact with the object 92. The location pin 104 may be moved a predetermined (or anticipated) distance into the housing 102. In the before welding position, the sensor 122 (or 122a, 122b, 122c or 122d) may be monitored by the respective circuit 124 (or 124a, 124b, 124c or 124d). The circuit 124 may report to the weld control circuit that the welding process may begin.

Referring to FIG. 11, a cross-sectional view after the welding is shown. The fastener 90 may move slightly closer to the object 92 as protrusions on a bottom of the fastener 90 melt and weld the fastener 90 to the object 92. The location pin 104 may move the slight distance further into the housing 102. In the after welding position, the sensor 122 (or 122a, 122b, 122c or 122d) may be monitored by the respective circuit 124 (or 124a, 124b, 124c or 124d). The circuit 124 may report to the weld control circuit that the welding process was successful.

Referring to FIG. 12, a cross-sectional view with an upside down fastener 90 is shown. Where the fastener 90 is turned upside down relative to the object 92, the location pin 104 may be moved an improper distance into the housing 102. The improper distance may be different from the predetermined distance due to a geometry difference on opposing sides of the fastener 90. For example, a top side of the fastener 90 (e.g., the side normally facing away from the object 92), may include a beveled inside edge 94 (also see FIG. 11). If the fastener 90 is upside down, the beveled inside edge 94 may allow the location pin 104 to protrude a further distance out of the housing 102 than would normally be expected. The circuit 124 may monitor the further distance and communicate to the weld control circuit to inhibit the welding process because the fastener 90 is mis-oriented.

Referring to FIG. 13, a perspective view of an example implementation of an apparatus 100c is shown. The apparatus 100c may be a variation of the apparatus 100, the apparatus 100a and/or the apparatus 100b. The apparatus 100c may be used to weld a fastener 90 (shown) and/or a weld stud 90a to the object 92. The apparatus 100c may include one or more sets of gears configured to increase an angular displacement of the sensors 122, 122a, 122b, 122c and/or 122d to provide better location measurements. Operation of the apparatus 100c may be similar to that of the apparatus 100, the apparatus 100a and/or the apparatus 100b.

The apparatus 100c generally includes the housing 102, the location pin 104, a spring (or assembly) 110b, a rotary lever (or arm) 112a, the shaft 114b, a shaft (or rod) 115, multiple gears 117a-117b and the sensor 122 (e.g., the rotary indicator 118 and the rotary indicator 120). The spring 110b (e.g., a rotary spring) may be a variation of the spring 110a. The spring 110b may be wound around the shaft 115 and anchored at a fixed location (e.g., the shaft 114b). The rotary lever 112a may be a variation of the rotary lever 112. Other elements of the apparatus 100, the apparatus 100a and/or the apparatus 100b may be included in the apparatus 100c.

The rotary lever 112a may be connected to the shaft 115 at one end and engages the location pin 104 at an opposite end. The linear motion of the location pin 104 may be converted (or translated) into an angular motion of the rotary lever 112a about the shaft 115. A center of rotation of the shaft 114 is generally offset from a centerline of the location pin 104.

The shaft 114b and the shaft 115 may be aligned to rotate on parallel axises. A gear 117a may be connected to an end of the shaft 114b opposite the rotary indicator 118. Another gear 117b may be connected to an end of the shaft 115. The gears 117a-117b may mesh such that rotation of the gear 117b causes a rotation of the gear 117a. A gear ratio in a range of 1.4:1 to 1.8:1 (e.g., 1.6:1) may cause the shaft 114a to turn at a faster rate as the shaft 115. Other gear ratios and/or numbers of gears may be implemented to meet the design criteria of particular applications.

Referring to FIG. 14, a cross-sectional view of an example implementation of an apparatus 100d is shown. The apparatus 100d may be a variation of the apparatus 100, the apparatus 100a, the apparatus 100b and/or the apparatus 100c. The apparatus 100d may be used to weld a fastener 90 and/or a weld stud 90a (shown) to the object 92. The apparatus 100d may also include one or more sets of gears configured to increase an angular displacement of the sensors 122, 122a, 122b, 122c and/or 122d to provide better location measurements. Operation of the apparatus 100d may be similar to that of the apparatus 100, the apparatus 100a, the apparatus 100b and/or the apparatus 100c.

The apparatus 100d generally includes the housing 102, a taper feature 103, the rotary spring 110b, the rotary lever 112a, the shaft 114b, the shaft 115, the gears 117a-117b, the sensor 122, a mount (or bracket) 131, a sensor (or device) 133 and a tube 154. Other elements of the apparatus 100, the apparatus 100a, the apparatus 100b and/or the apparatus 100c may be included in the apparatus 100d.

The taper feature 103 may be located at a bottom of the housing 102. The taper feature 103 may have a standard shape that allows the assembly 100d to be mounted on a welding machine. The taper feature 103 may be included on any of the assemblies 100, 100a, 100b, 100c and/or 100d.

The mount 131 may implement a sensor mount. The sensor mount 131 is generally configured to hold the sensor 133 in a specified location relative to the housing 102.

The sensor 133 may implement a spring loaded sensor. The spring loaded sensor 133 is generally operational to determine when the assembly 100d has a specified position relative to the object 92. In various embodiments, the sensor 133 may aid the weld control circuit to determine if a weld should proceed or not. If the sensor 133 detects the presence of the object 92 and the sensor 122 detects a proper positioning of the weld stud 90a, the welding may be performed. If the sensor 133 detects an improper location of the object 92, the welding may be inhibited even though the sensor 122 indicates proper placement of the weld stud 90a.

The tube 154 may implement a water tube. The water tube 154 may provide a flow of cooling water through the housing 102 to aid in drawing heat away from the assembly 100d. In various embodiments, the tube 154 may implement an air tube configured to provide a flow of cooling air (or other gas) through the housing 102 to aid in drawing heat away from the assembly 100d.

Referring to FIG. 15, a cross-sectional view of an apparatus 100e with a weld stud 90a in the load position is shown. The apparatus 100e may be a variation of the apparatus 100, the apparatus 100a, the apparatus 100b, the apparatus 100c and/or the apparatus 100d. The apparatus 100e may be used to attach the weld stud 90a to the object 92. The apparatus 100e is illustrated in a first configuration 101a. The apparatus 100e in the first configuration 101a generally comprises the housing 102, a stud push pin 104b, the cavity 106, the port 108, an optional port 109, the rotary lever (or toggle) 112, the shaft 114, a stud weld head (or electrode) 116a, the sensor (see FIG. 2) 122, the circuit (see FIG. 2) 124, the mount 131, a guide pin retainer 170, an O-ring 172, and an insulator 174.

The stud weld head 116a may be a variation of the weld head 116. The stud weld head 116a is configured to accommodate the weld stud 90b and to weld the weld stud 90b to the object 92.

The guide pin retainer 170 is disposed in the cavity 106 of the housing 102 and is configured to move linearly within the cavity 106 towards and away from the weld head 116a. The guide pin retainer 170 may define a slot 176. In various embodiments, the slot 176 generally has a “T” shape. The “T” shaped slot 176 may be inverted such that a horizontal portion of the “T” shape is oriented toward the insulator 174 and the vertical portion of the “T” shape is oriented toward the stud push pin 104b. Other shapes may be implemented in the slot to meet the design criteria of particular applications.

The O-ring 172 is generally disposed about a circumference of the guide pin retainer 170 to form an air-tight seal between the guide pin retainer 170 and the housing 102. The air-tight seal enables a control gas 180 applied at the port 108 of the housing 102 to bias the guide pin retainer 170 and the stud push pin 104b toward the weld stud 90a (e.g., with a high pressure) and alternately away from the weld stud 90a (e.g., with a low pressure or a negative pressure). The air-tight seal also enables a second control gas 181 applied to the port 109 to push the guide pin retainer 170 away from the weld stud 90a.

The insulator 174 implements a ceramic ball. The insulator 174 generally prevents a weld current 80 present in the stud push pin 104b and the guide pin retainer 170 from flowing into the rotary lever 112 and on to other parts of the assembly 100e. Other types of insulating material may be used to meet the design criteria of particular applications.

The stud push pin 104b may be a variation of the push pin 104a. The stud push pin 104b includes a rim 178 that has a size and a shape to fit inside the slot 176 of the guide pin retainer 170. The slot 176 and the rim 178 may interlock during welding operations. The slot 176 and the rim 178 also enable the stud push pin 104b to be easily interchanged with a different diameter stud push pin and/or with a different type of pin suitable for a different type of fastener in various configurations.

The port 109 provides a channel through the housing 102. The channel places the port 109 in fluid communication with the cavity 106 between the guide pin retainer 170 and the stud weld head 116a. The second control gas 181 may be applied to the port 109 to move the guide pin retainer 170 and the stud push pin 104b away from the weld stud 90a.

Referring to FIG. 16, a cross-sectional view of the apparatus 100e and the weld stud 90a before welding is shown. The weld stud 90a is closer to the object 92 than as illustrated in the load position in FIG. 15. Therefore, the stud push pin 104b and the guide pin retainer 170 have moved a corresponding distance into the housing 102 (e.g., downward in the illustration) from the load position. The rotary lever 112 transfers the motion to the sensor 122 (see FIG. 2). The sensor 122 may be monitored by the respective circuit 124 (see FIG. 2). While the before-welding position, the circuit 124 may report to the weld control circuit that the welding may proceed.

Referring to FIG. 17, a cross-sectional view of an apparatus 100f with another weld stud 90b before welding is shown. The apparatus 100f may be a variation of the apparatus 100, the apparatus 100a, the apparatus 100b, the apparatus 100c, the apparatus 100d and/or the apparatus 100e. The apparatus 100f may be used to attach the weld stud 90b to the object 92. The apparatus 100f generally comprises the housing 102, a stud push pin 104c, the cavity 106, the port 108, the optional port 109, the rotary lever 112, the shaft 114, the stud weld head 116a, the sensor (see FIG. 2) 122, the circuit (see FIG. 2) 124, the mount 131, the guide pin retainer 170, the O-ring 172, and the insulator 174.

In various embodiments, the weld stud 90b may have a flange 96 and a body 98. A diameter of the body 98 of the weld stud 90b may be smaller than a diameter of a body of the weld stud 90a shown in FIG. 15.

The stud push pin 104c may be a variation of the push pin 104a and/or the stud push pin 104b. The stud push pin 104c includes a cavity (or pocket) 105 at an end of the stud push pin 104c facing the weld stud 90b. The cavity 105 has a larger diameter than that of the body 98 of the weld stud 90b (and smaller than the diameter of the body of the weld stud 90a shown in FIG. 15).

While the weld stud 90b is in the before-welding position, the body 98 of the weld stud 90b extends into the cavity 105. Since the body 98 of the weld stud 90b does not move the stud push pin 104c a correct distance to indicate that the weld stud 90b and the object 92 are ready for welding, the circuit 124 may signal that the wrong fastener is present and so inhibits the welding.

Referring to FIG. 18, a cross-sectional view of an apparatus 100g with another fastener 90c in the load position is shown. The apparatus 100g may be a variation of the apparatus 100, the apparatus 100a, the apparatus 100b, the apparatus 100c, the apparatus 100d, the apparatus 100e and/or the apparatus 100f. The apparatus 100g may be used to attach the fastener 90c to the object 92. The apparatus 100g is illustrated in a second configuration 101b. The apparatus 100g in the second configuration 101b generally comprises the housing 102, a nut location pin 104d, the cavity 106, the port 108, the optional port 109, the rotary lever 112, the shaft 114, a nut weld head (or electrode) 116b, the sensor (see FIG. 2) 122, the circuit (see FIG. 2) 124, the mount 131, the guide pin retainer 170, the O-ring 172, and the insulator 174.

In various embodiments, the fastener 90c may be a variation of the fastener 90. In other embodiments, the fastener 90c is the same as the fastener 90. The fastener 90c generally implements a weld nut.

The nut location pin 104d may be a variation of the location pin 104. The nut location pin 104d may include the rim 178 that is configured to mate with the slot 176 of the guide pin retainer 170.

The nut weld head 116b may be a variation of the weld head 116 and/or the stud weld head 116a. The nut weld head 116b is configured to accommodate the fastener 90c and to weld the fastener 90c to the object 92.

After the welding has completed, the control gas 180 may be applied to the port 108 with a negative pressure to draw the guide pin retainer 170 and the nut location pin 104d out of the fastener 90c and the object 92. Alternatively, the second control gas 181 may be applied to the port 109 with a positive pressure to force the guide pin retainer 170 and the nut location pin 104d out of the fastener 90c and the object 92.

The nut location pin 104d in the second configuration 101b is designed to be interchangeable with the stud location pin 104b and/or the stud location pin 104c in the first configuration 101a. The interchangeability may be achieved by at least using the same rim 178 and the same diameter in each pin 104b/104c and 104d at the guide pin retainer 170. The nut weld head 116b in the second configuration 101b is designed to be interchangeable with the stud weld head 116a in the first configuration 101a. The interchangeability may be achieved by at least using the same threads on both weld heads 116a and 116b to screw into the housing 102.

Referring to FIG. 19, a cross-sectional view of an apparatus 100h with the weld stud 90b in the load position is shown. The apparatus 100h may be a variation of the apparatus 100, the apparatus 100a, the apparatus 100b, the apparatus 100c, the apparatus 100d, the apparatus 100e, the apparatus 100f and/or the apparatus 100g. The apparatus 100h may be used to attach the weld stud 90b to the object 92. The apparatus 100h is illustrated in a third configuration 101c. The apparatus 100h in the third configuration 101c generally comprises the housing 102, a stud push pin 104e, the cavity 106, the port 108, the rotary lever 112, the shaft 114, a stud weld head (or electrode) 116c, the sensor (see FIG. 2) 122, the circuit (see FIG. 2) 124, the mount 131, the guide pin retainer 170, the O-ring 172, and the insulator 174.

The stud push pin 104e may be a variation of push pin 104a, the stud push pin 104b, the stud push pin 104c and/or the stud push pin 104d. The stud push pin 104e may include the rim 178 that is configured to mate with the slot 176 of the guide pin retainer 170.

The stud weld head 116c may be a variation of the weld head 116, the stud weld head 116a and/or the stud weld head 116b. The nut weld head 116c is configured to accommodate the weld stud 90b and to weld the weld stud 90b to the object 92.

The stud push pin 104e in the third configuration 101c is designed to be interchangeable with the stud push pin 104a in the first configuration 101a. The interchangeability may be achieved by at least using the same rim 178 and the same diameter in each stud push pin 104a and 104e at the guide pin retainer 170. The stud weld head 116c in the third configuration 101c is designed to be interchangeable with the stud weld head 116a in the first configuration 101a. The interchangeability may be achieved by at least using the same threads on both weld heads 116a and 116c to screw into the housing 102.

The functions and structures illustrated in the diagrams of FIGS. 1-19 may be designed, modeled and simulated using one or more of a conventional general-purpose processor, digital computer, microprocessor, microcontroller and/or similar computational machines, programmed according to the teachings of the present specification, as will be apparent to those skilled in the relevant art(s). Appropriate software, firmware, coding, routines, instructions, opcodes, microcode, and/or program modules may readily be prepared by skilled programmers based on the teachings of the present disclosure, as will also be apparent to those skilled in the relevant art(s). The software is generally embodied in a medium or several media, for example a non-transitory storage media, and may be executed by one or more of the processors.

While the invention has been particularly shown and described with reference to the preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made without departing from the scope of the invention.

Claims

1. An apparatus comprising: a housing that defines a cavity;a weld head removably coupled to said housing and configured to apply a welding current to weld an object to a fastener;a guide pin retainer configured to move linearly within said cavity, wherein said guide pin retainer defines a slot with a “T” shape;a pin removably coupled to said slot and extending from said guide pin retainer to engage said fastener;a sensor configured to measure a position of said pin; anda circuit configured to generate a status of said fastener based on said position, wherein said status indicates that said fastener is selectively one of a properly oriented fastener, an improperly oriented fastener, and a wrong fastener.

2. The apparatus according to claim 1, further comprising: a rotary lever configured to transfer said position of said pin to said sensor.

3. The apparatus according to claim 2, further comprising: a ball disposed between said pin and said rotary lever, wherein said ball electrically insulates said rotary lever from said welding current present in said pin.

4. The apparatus according to claim 1, wherein: said housing further defines a port in fluid communication with said cavity on an opposite side of said guide pin retainer from said weld head; andsaid port is configured to transfer a control gas.

5. The apparatus according to claim 4, wherein said guide pin retainer and said pin are alternatively extended and retracted in response to said control gas.

6. The apparatus according to claim 1, wherein: said pin defines a cavity on a side of said pin facing said guide pin retainer;said fastener is a weld stud; andsaid weld stud includes a flange and a body.

7. The apparatus according to claim 6, wherein said circuit indicates that said fastener is said wrong fastener in response to said body of said weld stud extending into said cavity.

8. The apparatus according to claim 1, wherein: in a first configuration, said pin is a nut location pin that extends out of said housing and through said fastener and said weld head is a nut weld head; andin a second configuration, said pin is a stud push pin that contacts said fastener within said cavity, and said weld head is a stud weld head.

9. The apparatus according to claim 8, wherein said nut location pin and said nut weld head of said first configuration are interchangeable with said stud push pin and said stud weld head of said second configuration.

10. The apparatus according to claim 1, wherein said apparatus forms part of a welding electrode.

11. A method for position sensing in a welding electrode, the method comprising: removably coupling a weld head to a housing, wherein said weld head is configured to apply a welding current to weld and object to a fastener, and said housing defines a cavity;moving a guide pin retainer linearly in said cavity, wherein said guide pin retainer defines a slot with a “T” shape;removably coupling a pin to said slot, wherein said pin extends from said guide pin retainer toward said fastener;engaging said fastener with said pin;measuring a position of said pin with a sensor; andgenerating in a circuit a status of said fastener based on said position, wherein said status indicates that said fastener is selectively one of a properly oriented fastener, an improperly oriented fastener, and a wrong fastener.

12. The method according to claim 11, further comprising: transferring said position of said pin through a rotary lever to said sensor.

13. The method according to claim 12, further comprising: electrically insulating said rotary lever from said welding current present in said pin with a ball, wherein said ball is disposed between said pin and said rotary lever.

14. The method according to claim 11, further comprising: transferring a control gas through a port in said housing, wherein said port is in fluid communication with said cavity on an opposite side of said guide pin retainer from said weld head.

15. The method according to claim 14, further comprising: extending and alternatively retracting said guide pin retainer and said pin in response to said control gas.

16. The method according to claim 11, wherein: said pin defines a cavity on a side of said pin facing said guide pin retainer;said fastener is a weld stud; andsaid weld stud includes a flange and a body.

17. The method according to claim 16, further comprising: indicating that said fastener is said wrong fastener in response to said body of said weld stud extending into said cavity.

18. The method according to claim 11, wherein: in a first configuration, said pin is a nut location pin that extends out of said housing and through said fastener and said weld head is a nut weld head; andin a second configuration, said pin is a stud push pin that contacts said fastener within said cavity, and said weld head is a stud weld head.

19. The method according to claim 18, further comprising: interchanging said nut location pin and said nut weld head of said first configuration with said stud push pin and said stud weld head of said second configuration.

20. The method according to claim 11, wherein said method is performed in said welding electrode.