US20050252269A1

US20050252269A1 - Toggle press

Info

Publication number: US20050252269A1
Application number: US10/844,618
Authority: US
Inventors: Edwin Sawdon; Steven Sprotberry
Original assignee: BTM Corp
Current assignee: BTM Corp
Priority date: 2004-05-12
Filing date: 2004-05-12
Publication date: 2005-11-17
Also published as: CN1695937A

Abstract

A press for translating a tool includes a first member, a second member and a plurality of retention members. The first member is drivingly coupled to an actuator. The first member is axially moveable between first and second positions in response to movement of the actuator. The first member includes a first end surface having a plurality of circumferentially spaced apart detents. The second member is threadably engaged with the first member. The first and second members define an assembly having a length. The retention members are positioned between the first and second members. Each retention member is biasedly engaged with one of the detents to provide resistance to relative rotation between the first and second members. The resistance to relative rotation may be overcome to adjust the length of the assembly.

Description

FIELD OF THE INVENTION

The present invention relates generally to sheet metal forming devices and, more particularly, to a sheet metal forming press incorporating unique force generating and translating mechanisms.

BACKGROUND OF THE INVENTION

In the manufacture of products, there is often a need to join several pieces of material such as sheet metal to build various assemblies and subassemblies. There are many different means for accomplishing this joining task. For example, there is adhesive bonding, welding, or cold deformation. Both bonding and welding processes require the introduction of a foreign material to the assembly. The foreign material can tend to fail, thereby weakening the assembly. In cold deformation, several pieces of sheet material are plastically deformed in such a manner that they are locked together. Depending on the thickness, strength, and/or the number of pieces of material to be joined, a great amount of force is required to accomplish this task.
Traditional presses for providing this force include in-line hydraulic presses and accordion-type toggle presses. Such presses, however, are often heavy and include many intricate parts making maintenance difficult and time consuming.

SUMMARY OF THE INVENTION

A press for translating a tool and drivingly engaging a workpiece is provided. The press generally includes a press body, a piston, a sensor pin, and a sensor. The press body defines a cavity. The piston is disposed within the cavity and is pivotable between a first position and a second position. The piston includes a trunnion defining a trunnion face and a plurality of pin recesses. The sensor pin is disposed in one of the plurality of pin recesses. The sensor is supported by the press body substantially axially aligned with the trunnion. The sensor is operable to detect the presence of the sensor pin and determine when the piston is in the first and second positions.
Another aspect of the present invention provides a press body containing an actuation device including a piston, a press link, and a link pin. The piston is movable between a first position and a second position. The press link includes a first yoke receiving the piston. The first yoke includes a first leg and a second leg. The first leg includes a first aperture. The second leg includes a second aperture. The first aperture is substantially circular and the second aperture includes a rotation limiting surface. The first link pin extends through the first and second legs and the piston. The first link pin includes a first end, a body portion, a second end, and a network of internal cavities. The first end engages the first aperture. The body portion has a substantially cylindrical bearing surface rotatably supporting the piston. The second end engages the second aperture and has a rotation limiting surface engaging the rotation limiting surface of the second aperture. This prevents rotation of the first link pin relative to the press link. The internal cavities of the network fluidly communicate with the bearing surface and are adapted to contain and dispense a lubricant.
Another aspect of the present invention provides a press for translating a tool including a first member, a second member and a plurality of retention members. The first member is drivingly coupled to an actuator. The first member is axially moveable between first and second positions in response to movement of the actuator. The first member includes a first end surface having a plurality of circumferentially spaced apart detents. The second member is threadably engaged with the first member. The first and second members define an assembly having a length. The retention members are positioned between the first and second members. Each retention member is biasedly engaged with one of the detents to provide resistance to relative rotation between the first and second members. The resistance to relative rotation may be overcome to adjust the length of the assembly.
Another aspect of the present invention provides a press for translating a tool including a press body, an actuator, a ram assembly, a tool assembly and a quick release mechanism. The actuator is supported by the press body. The ram assembly is drivingly coupled to the actuator. The ram assembly is linearly moveable in an advanced direction and a retracting direction. The tool assembly is coupled to an end of the ram assembly opposite the actuator. The quick release mechanism includes a pin removably attaching the tool assembly to the ram assembly. A load being transferred to the tool assembly during movement of the ram assembly in the advancing direction bypasses the pin. The tool assembly is disconnectable from the ram assembly by removal of the pin without the use of hand tools.
Another aspect of the present invention provides a press for translating a tool including a press body, an actuator, a ram assembly, a lower tool assembly and a quick release mechanism. The press body has an upper jaw and a lower jaw. The actuator is supported by the press body. The ram assembly is drivingly coupled to an actuator and slidably positioned within the upper jaw. The lower tool assembly is supported by the lower jaw of the press body axially below the ram assembly. The lower tool assembly includes a shoulder portion engaging the lower jaw and a shank portion including a transverse aperture engaging an axial bore extending through the lower jaw. The quick release mechanism includes a pin removably attaching the lower tool assembly to the press body. The lower tool assembly is disconnectable from the press body by removing the pin without the use of hand tools.
Another aspect of the present invention provides a press for translating a tool including a press body, a first actuator, a tool assembly, a second actuator, a guide assembly and a sensor. The first actuator is coupled to the press body. The tool assembly is coupled to the first actuator and supported by the press body for drivingly engaging a workpiece. The second actuator is attached to the press body and adapted to translate the press body relative to a mounting member. The guide assembly interconnects the mounting member and the press body. The drive assembly includes a translation limiting mechanism operable to adjust the range of translation of the press body between various extended and retracted positions. The sensor is fixedly attached to the guide assembly and operable to detect the position of the press body when located at the extended and retracted positions.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:
FIG. 1 is a perspective view of a press in accordance with the principles of the present invention;
FIG. 2 is a side view of the press of FIG. 1 with a cover plate removed to illustrate an exemplary actuation device and ram assembly in a first position;
FIG. 3 is a side view of the press of FIG. 2 illustrating the actuation device in a second position;
FIG. 4 is an exploded perspective view of the press of FIG. 1;
FIG. 5 is an exploded perspective view of the actuation device and a portion of the cover plate of the press of FIG. 1;
FIG. 6 is a cross-sectional view of a ram assembly of the press of FIG. 1;
FIG. 7 is an exploded perspective view of the ram assembly of FIG. 6;
FIG. 8 is a cross-sectional view of a punch assembly of the press of FIG. 1;
FIG. 9 is an exploded perspective view of the punch assembly of FIG. 8;
FIG. 10 is a cross-sectional view of a lower tooling assembly of the press of FIG. 1;
FIG. 11 is an exploded perspective view of the lower tooling assembly of FIG. 10;
FIG. 12 is a perspective view of the press of FIG. 1 coupled to an equalizer assembly in a first position;
FIG. 13 is a perspective view of the press and equalizer assembly of FIG. 12 in a second position;
FIG. 14 is an exploded perspective view of the equalizer assembly and a portion of the press of FIGS. 12 and 13;
FIG. 15 is an exploded perspective view of an alternate embodiment ram assembly;
FIG. 16 is a top view of the ram assembly of FIG. 15;
FIG. 17 is a cross-sectional view of the ram assembly of FIG. 15; and
FIG. 18 is another cross-sectional view of the ram assembly depicted in FIG. 15.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description of the preferred embodiments is merely exemplary in nature and is in no way intended to limit the scope of the invention, its application, or its uses.
With reference to FIGS. 1-4, a press 10 in accordance with the present invention is described. The press 10 generally includes a press body 12, an actuation device 14, a ram assembly 16, and a lower tooling assembly 18. The actuation device 14 (shown in FIGS. 2-4) is operable to axially reciprocate the ram assembly 16 between a retracted position (shown in FIG. 2) and an extended position (shown in FIG. 3). The ram assembly 16 is adapted to engage a workpiece against the lower tooling assembly 18 to form a desired joint.
The press body 12 includes an actuation cavity 20, a ram bore 21, first and second cover plates 22, 24, an upper pneumatic port 26, an upper lubrication port 27, a lower pneumatic port 28, a lower lubrication port 29, a throat 30, and a set of apertures comprising a mounting pattern 31. The actuation cavity 20 includes a pair of radial walls 20 a, 20 b and a semi-circumferential outer wall 20 c. The radial walls 20 a, 20 b are spaced apart from one another and define a swept arc length of approximately 90°. The first and second cover plates 22, 24 are removably fixed to opposite sides of the press body 12 with a plurality of fasteners 25 such as screws or bolts. The cover plates 22, 24 provide an airtight seal to the actuation cavity 20. The cover plates 22, 24 also ensure that the actuation device 14 remains substantially protected from dust and debris during operation of the press 10. The upper 26 and lower 28 pneumatic ports extend through the press body 12 and are in communication with the actuation cavity 20. In an exemplary embodiment, a compressor (not shown), or similar device, is operable to selectively supply pressurized air to the upper 26 and lower 28 pneumatic ports and provide a pneumatic impetus to the actuation device 14. The upper and lower lubrication ports 27, 29 are adapted to carry a lubricant to the actuation device 14 and ram assembly 16, respectively. The throat 30 defines an upper jaw 32 and a lower jaw 34. The throat 30 is adapted to receive a workpiece prior to and during a joining operation.
With specific reference to FIGS. 2-5, the actuation device 14 generally includes a piston 36, a press link 38, an upper link pin 40, a lower link pin 42, and a proximity sensor 44. The piston 36 includes a one-piece member defining a trunnion 46, a wiper arm 48, and a link ring 50. The piston further includes a groove 51 for receipt of two substantially rectangular seals (not shown). The rectangular seals are V-shaped in cross-section and sealingly engage inner surfaces of the cover plates 22, 24 as well as the walls of cavity 20. The wiper arm 48 of the piston 36 is adapted to pivot between a first position adjacent the first radial wall 20 b of the cavity 20 (shown in FIG. 2) and a second position adjacent the second radial wall 20 a of the cavity 20 (shown in FIG. 3). It is envisioned that in an alternative embodiment, a stroke wedge 52 (shown in phantom in FIG. 3) may be inserted into the actuation cavity 20 adjacent the first radial wall 20 b. The stroke wedge 52 provides a third position for the wiper arm 48 of the piston 36. The third position would provide a shortened stroke for the ram assembly 16. A shortened stroke for the ram assembly 16 enables larger dimensioned workpieces to be joined. It is further envisioned that stroke wedges 52 of different circumferential dimensions could be implemented to provide multiple stroke variations.
FIG. 5 depicts the press link 38 as including an upper yoke 54 and a lower yoke 56. The upper yoke 54 includes a first leg 58 and a second leg 60. The first leg 58 includes an aperture 62 having a generally circular cross-section. The second leg 60 includes an aperture 61 having generally cylindrically shaped portion 63 and an adjacent portion 64 having a generally D-shaped cross-section. The aperture portion 64 in the second leg 60 defines a rotation limiting surface 64 a and an arched surface 64 b. The arched surface 64 b has a radius that is larger than the radius of the aperture 62 in the first leg 58. The lower yoke 56 includes a third leg 66 and a fourth leg 68. The third leg 66 includes an aperture 70 having a generally circular cross-section. The fourth leg 68 includes an aperture 72 having a generally D-shaped cross-section. The D-shaped portion of aperture 72 in the fourth leg 68 defines a rotation limiting surface 72 a and an arched surface 72 b. The arched surface 72 b has a radius larger than the radius of the aperture 70 in the third leg 66. The upper link pin 40 drivingly couples the press link 38 to the piston 36 through the link ring 50 and the upper yoke 54. The lower link pin 42 drivingly couples the press link 38 to the ram assembly 16 as will be discussed in more detail below.
The upper link pin 40 includes a first end 74, a second end 76, a bearing surface 78, and a network of internal cavities 80. The first end 74 is generally circular in cross-section. The first end 74 engages aperture 62 in the first leg 58 of the upper yoke 54. The second end 76 has a generally D-shaped cross-section defining a rotation limiting surface 76a and an arched surface 76 b. The arched surface 76 b has a smaller radial dimension than the bearing surface 78. The second end 76 engages aperture 64 in the second leg 60 of the upper yoke 54. The rotation limiting surface 64 a of upper yoke 54 engages rotation limiting surface 76 a of upper link pin 40 to maintain the rotational position of the upper link pin 40 relative to the press link 38. Lastly, a first snap ring 75 engages a groove (not shown) in the aperture 62 of the first leg 58. The snap ring 75 maintains the axial position of the first link pin 40 in the upper yoke 54. The bearing surface 78 rotationally engages an inner circumferential surface 77 of the link ring 50 of the piston 36. In an exemplary embodiment, the bearing surface 78 has a diameter in close tolerance to the inner circumferential surface 77 of the link ring 50. The network of internal cavities 80 includes an axial bore 80 a and a plurality of radial bores 80 b in fluid communication with one another. The radial bores 80 b are further in fluid communication with the bearing surface 78. The network of internal cavities 80 contains a lubricant, such as oil or grease, and are adapted to dispense the lubricant to the bearing surface 78. This ensures proper lubrication between the bearing surface 78 and the link ring 50.
The lower link pin 42 is constructed substantially similarly to the upper link pin 40. The lower link pin 42 includes a third end 82, a fourth end 84, a bearing surface 86, and a network of internal cavities 88. The third end 82 is generally circular in cross-section. The third end 82 engages the aperture 70 in the third leg 66 of the lower yoke 56. The fourth end 84 is generally D-shaped in cross-section. The fourth end 84 defines a rotation limiting surface 84 a and an arched surface 84 b. The arched surface 84 b has a smaller radial dimension than the bearing surface 86. The fourth end 84 engages the aperture 72 in the fourth leg 68 of lower yoke 56. The rotation limiting surfaces 72 a, 84 a of the lower yoke 56 and the lower link pin 42 engage to maintain the rotational position of the lower link pin 42 relative to the press link 38. Lastly, a second snap ring 85 engages a groove (not shown) in the aperture 70 in the third leg 66. The snap ring 85 maintains the axial disposition of the lower link pin 42. The arched surface 84 b has a smaller radial dimension than the bearing surface 86. The network of internal cavities 88 in the lower link pin 42 are substantially similar to the network of internal cavities 80 in the upper link pin 40. The network of internal cavities 88 operate to provide lubrication to the interface between the bearing surface 86 of the lower link pin 42 and the ram assembly 16. Therefore, it should be appreciated that the present design provides the advantages of preventing relative rotation between the link pins 40, 42 and the press link 38, while enabling lubricated rotation between the upper link pin 40 and the piston 36 as well as between the lower link pin 42 and the ram assembly 16.
With continued reference to FIG. 5, the interrelationship between the piston 36 and proximity sensor 44 of the actuation device 14 is described. The proximity sensor 44 is attached to the first cover plate 22 and is axially aligned with the trunnion 46 of the piston 36. The trunnion 46 includes a cylindrical bearing surface 90, a trunnion face 92, and a network of internal cavities 94. The trunnion face 92 includes an upper arcuate slot 96 and a lower arcuate slot 98. The upper arcuate slot 96 includes a plurality of pin recesses 100 (shown in FIGS. 2 and 3). The network of internal cavities 94 are in fluid communication with the bearing surface 90 and adapted to contain and dispense a lubricant such as oil or grease.
The proximity sensor 44 includes a sensor body 102, a first sensor probe 104, a second sensor probe 106, and a sensor pin 108 (FIGS. 2 and 3). The sensor body 102 is adapted to be attached to an output device. It is envisioned that the output device may provide an audible, visual, or combination of audible and visual signal. The first and second sensor probes 104, 106 include end portions 104 a, 106 a that extend through apertures in the first cover plate 22. The end portions 104 a, 106 a are disposed substantially flush with the trunnion face 92 and aligned with the upper and lower arcuate slots 96, 98. The sensor pin 108 is selectively positioned in one of the plurality of pin recesses 100 in the upper arcuate slot 96 of the trunnion 46. In FIGS. 2 and 3, the sensor pin 108 is located in the clockwise most pin recess 100. In this position, the sensor probe 106 detects the sensor pin 108 when the wiper arm 48 is positioned adjacent the first radial wall 20 b. Sensor probe 104 detects sensor pin 108 when the wiper arm 48 is positioned adjacent to the second radial wall 20 a. The sensor pin 108 may be positioned in the middle pin recess 100. In this position, the sensor probe 104 detects the sensor pin 108 when the wiper arm 48 is positioned adjacent the stroke wedge 52 (shown in phantom). Thus, it should be appreciated that this configuration provides a versatile sensing system for the press 10. The present design enables the sensor 44 to detect the position of the piston 36, even when the stroke of the ram assembly 16 is altered via a stroke wedge 52. The proximity sensor 44 is operable to detect the presence of the sensor pin 108 and output a signal indicating the position of the piston 36. In an exemplary embodiment, the sensor pin 108 is a metal screw and the first and second sensor probes 104,106 include magnetic devices.
With reference now to FIGS. 6 and 7, the ram assembly 16 is described in detail. The ram assembly 16 includes a ram base 110, a press ram 112, a biasing mechanism 114, a punch holder 115 and a punch assembly 116 (shown in FIGS. 8 and 9). The ram base 110 and press ram 112 are threadably coupled together to enable adjustments to the axial overall length of the ram assembly 16. The biasing mechanism 114 acts to secure the ram assembly 16 from involuntary adjustments.
The ram base 110 includes a substantially cylindrical member disposed in the ram bore 21 of the press body 12 (shown in FIGS. 2 and 3). The ram base 110 includes a transverse bore 117, an external threaded portion 118, and an end surface 120. The transverse bore 117 receives the lower link pin 42 of the actuation device 14, as described above. The end surface 120 includes a plurality of indentations 122 circumferentially spaced apart from one another. In the embodiment illustrated, the plurality of indentations 122 includes eight indentations. Each indentation 122 has a conical geometry and may be formed using a drill point.
The press ram 112 includes a first end 112 a and a second end 112 b. The first end 112 a includes a bore 124, an internal threaded portion 126, and a plurality of blind bores 128. Each blind bore 128 contains at least a portion of the biasing mechanism 114. The second end 112 b includes a tool bore 130, a pair of transverse apertures 132 a, 132 b, and a marking 134. A fastener bore 133 interconnects bore 130 with bore 124. The internal threaded portion 126 of the first end 112 a threadably engages the external threaded portion 118 of the ram base 110. This provides for an overall length adjustment of the ram assembly 16, as will be described in more detail below. The tool bore 130 is stepped to align the punch holder 115 with a longitudinal axis of the press ram 112. A fastener 135 threadingly engages punch holder 115 to couple the punch holder to press ram 112.
The biasing mechanism 114 includes a plurality of pins 138, and a plurality of biasing members 140. In the embodiment illustrated, the plurality of biasing members 140 include coil springs. Each coil spring 140 is positioned within a corresponding blind bore 128. The plurality of pins 138 each include a first end 138 a and a second end 138 b. The first ends 138 a include longitudinal bores receiving the biasing members 140, as shown in FIG. 6. The second ends 138 b are rounded and received by the plurality of indentations 122 in the end surface 120 of the ram base 110. The biasing members 140 provide an axial load on the plurality of pins 138 to maintain their engagement with the plurality of indentations 122. Accordingly, relative rotational displacement of the ram base 110 and the press ram 112 is somewhat restricted.
In an exemplary embodiment, the external and internal threaded portions 118, 126 include a predetermined thread pitch such that one revolution of the press ram 112 relative to the ram base 110 provides a predetermined axial adjustment of the ram assembly 16. In the embodiment illustrated, the external threaded portion 118 includes a diameter of one and one-eighth inch and thirty-two threads per inch. One revolution of the press ram 112 relative to the ram base 110, therefore, provides an axial displacement of approximately 0.032 inches. Additionally, because there are eight equally spaced apart pins 138, a single click between pins 138 equates to a rotational angle of approximately 45 degrees. This rotational amount provides an axial displacement of the ram assembly 16 of approximately 0.004 inches. It should be appreciated that such simple and accurate axial adjustment of the ram assembly 16 is highly advantageous when using the press 10 for multiple joining applications.
Furthermore, as stated above, a marking 134 is included on the press ram 112. The marking 134 provides a datum line for adjusting the axial dimension of the ram assembly 16. For example, with the ram assembly 16 in the retracted position (as shown in FIG. 2), the press ram 112 can be rotated relative to the ram base 110 such that the marking 134 is substantially flush with the upper jaw 32 of the press body 12. When this situation exists, the axial dimension of the ram assembly 16 is known to be some predetermined length. The press ram 112 can then be rotated to adjust the length in 0.004 inch increments. It is envisioned that the press ram 112 may also include further markings to establish datum lines for the ram assembly 16 when a stroke wedge 52 is utilized, as discussed above in reference to FIG. 3. Furthermore, it should be appreciated that the threads and numbers of pins 138 utilized can be altered to achieve alternative incremental adjustments for the ram assembly 16.
FIGS. 8-9 depict the punch assembly 116 including a collar 142, a punch 144, a stripper 146, a spring spacer 148, a biasing member 150, and a quick release mechanism 152. The collar 142 is a substantially annular member including a shoulder portion 142 a and a shank portion 142 b. The shank portion 142 b includes external threads 154 and a plurality of U-shaped recesses 156. The shoulder portion 142 a includes a plurality of transverse bores 158. The external threads 154 threadably engage the internal threaded portion 136 of the second end 112 b of the press ram 112. The apertures 132 a, 132 b in the press ram 112 are substantially aligned with a pair of the U-shaped recesses 156 in shank portion 142 b of the collar 142.
The punch 144 includes an elongated cylindrical member having a transverse bore 160 and a tool portion 162. The punch 144 is disposed through the collar 142 and extends into a bore 163 of the punch holder 115. The transverse bore 160 in the punch 144 is substantially aligned with the U-shaped recesses 156 in the collar 142 and the apertures 132 a, 132 b in the press ram 112. The tool portion 162 is adapted to engage a workpiece.
The stripper 146 includes a shoulder portion 146 a and a sleeve portion 146 b. The shoulder portion 146 a includes a hollow cylindrical member defining a pair of vertical slots 164. The sleeve portion 146 b includes a hollow cylindrical member defining a stripper aperture 166. The stripper 146 receives the punch 144 such that the vertical slots 164 are substantially aligned with the transverse bore 160 in the punch 144 and the U-shaped recesses 156 in the collar 142. The biasing member 150 includes a compression spring disposed within the tool bore 130 of the press ram 112. The spring spacer 148 includes a solid annular member disposed within the tool bore 130 axially between the biasing member 150 and the stripper 146. The biasing member 150 is adapted to bias the stripper 146 away from the ram assembly 16.
The quick release mechanism 152 includes a detent pin 168 having a spring biased detent 170. The detent pin 168 extends through the apertures 132 a, 132 b in the press ram 112, the pair of U-shaped recesses 156 in the collar 142, the transverse bore 160 in the punch 144, and the vertical slots 164 in the stripper 146. In this manner, the detent pin 168 prevents rotation of the punch assembly 116 relative to the press ram 112. It should be appreciated that the detent pin 168 does not carry any load created by the actuation device 14 through the ram assembly 16. Rather, the axial load is transferred through the ram assembly 16 via the punch holder 115 to punch 144. An advantage of this design lies in the quick release mechanism 152. The detent pin 168 includes a ring 172. A user of the press 10 can simply grasp the ring 172 and extract the detent pin 168 from the ram assembly 16. This enables the punch 144 and stripper 146 to be removed without tools. Therefore, the punch 144 can be quickly and easily swapped out for another punch and stripper designed to provide a different joint.
FIGS. 10 and 11 show the lower tooling assembly 18 statically supported by the lower jaw 34 of the press body 12. The lower jaw 34 includes an axial bore 174, a pair of axially aligned transverse bores 176, and a locking bore 178. The axial bore 174 receives a portion of the lower tooling assembly 18. The lower tooling assembly 18 includes a tool holder 180, a die assembly 182, and a quick release mechanism 184. The tool holder 180 includes a generally cylindrical member having a shoulder portion 180 a, a shank portion 180 b, a tool bore 186, a fastener bore 188, and a pair of transverse apertures 192. The tool bore 186 extends axially through the shoulder portion 180 a and partly into the shank portion 180 b. The fastener bore 188 is radially conjoined with the tool bore 186. The fastener bore 188 also includes a threaded blind bore 190 for receiving a fastener 200 and a washer 201.
The die assembly 182 generally includes a cylindrical column 194 supporting a tool die 196. The die assembly 182 is disposed in the tool bore 186 of the tool holder 180. The tool die 196 includes a die for providing a TOG-L-LOC® type joint between two workpieces. Such a die is described in greater detail in U.S. Pat. No. 6,092,270, the entire disclosure of which is hereby incorporated by reference herein. The cylindrical column 194 further includes a pocket 198 formed on an outer cylindrical surface of the column. The pocket 198 is aligned with the fastener bore 188 in the tool holder 180. The screw 200 includes a head 202 positioned in the fastener bore 188. The washer 201 is positioned below the head 202 and engages the pocket 198 in the column 194 to prevent undesired removal of the die assembly 182 from the tool bore 186. The shoulder portion 180 a of the tool holder 180 engages the lower jaw 34 of the press body 12 to support the lower tooling assembly 18. The transverse apertures 192 in the tool holder 180 are substantially aligned with the transverse bores 176 in the lower jaw 34.
The quick release mechanism 184 includes a detent pin 204 having a spring biased detent 206 and a ring 208. The detent pin 204 extends through the transverse bores 176 in the lower jaw 34 such that the spring biased detent 206 engages the locking bore 178. As such, the detent pin 204 extends through the transverse apertures 192 in the tool holder 180 to maintain the tool holder 180 in the axial bore 174. This design provides for toolless removal of the lower tooling assembly 18 from the press body 12. The ring 208 is simply grasped by a user and the detent pin 204 can quickly and easily be removed to interchange the tool holder 180 with an alternative tool holder.
During operation, a plurality of workpieces (not shown) are placed over the lower tooling assembly 18 when the actuation device 14 is in its retracted position, as shown in FIG. 2. Then, a compressor, or similar device, provides pressurized fluid to the upper pneumatic port 26. The wiper arm 48 of the piston 36 travels from the first radial wall 20 b to the second radial wall 20 a. Simultaneously with the piston 36 traveling as just described, the press link 38 drives the ram assembly 16 toward the lower tooling assembly 18. The tool portion 162 of the punch 144 engages the workpiece before the wiper arm 48 of the piston 36 engages the second radial wall 20 a of the actuation cavity 20. This initiates the forming process. Once the wiper arm 48 of the piston 36 reaches the second radial wall 20 a, upper pneumatic port 26 is exhausted to atmosphere and pressurized fluid is supplied to the lower pneumatic port 28 to force the piston 36 back toward the first radial wall 20 b. This, in turn, retracts the ram assembly 16 to the position shown in FIG. 2. The joined workpieces are then removed.
The press 10 of the present invention provides an override feature during the above-described process. A sensor 210, such as a strain gauge, is positioned on the press body 12 adjacent the throat 30. The sensor 210 is positioned here because this is the point of the press body 12 that experiences the most stress during the above-described process. The sensor 210 is operable to detect stress applied to the press body 12 and output a signal accordingly. In an exemplary embodiment, the sensor 210 communicates with a controller operable to control the supply of pressurized air from the compressor. For example, if the sensor 210 detects a stress level greater than a predetermined threshold, the sensor instructs the controller to discontinue the press operation. This function provides for an override feature for the press 10 in situations when the punch may be broken or when piston 36 or ram assembly 16 have become obstructed.
FIGS. 12-14 illustrate an alternative embodiment of the present invention, wherein the press 10 further includes an equalizer assembly 212. The equalizer assembly 212 is adapted to be mounted to a working surface such as a workbench or a robot arm. The equalizer assembly 212 is operable to translate the press 10 along a linear axis between a first position (shown in FIG. 12) and a second position (shown in FIG. 13).
The equalizer assembly 212 generally includes an actuator 214, a guide assembly 216, and a sensor 218. The actuator 214 includes a cylinder 220 and a piston 222, wherein the piston 222 is driven by a pneumatic source (not shown) applied to the cylinder 220. The cylinder 220 is fixed to the press body 12 via threaded fasteners 223. The piston 222 is drivingly coupled to the guide assembly 216 by a pin 225.
The guide assembly 216 includes a stop adjust rod 224, an equalize block 226, an equalize mount block 228, a lower stop collar 230, an upper stop collar 232, a plurality of slide brackets 234, and a plurality of slides 236. The equalize block 226 is mounted to the press body 12 via threaded fasteners 227 and includes a threaded bore 226 a. The stop adjust rod 224 is a substantially cylindrical elongated member having an external thread over its entire length 224 a threadably engaging the threaded bore 226 a in the equalize block 226. The equalize mount block 228 includes an aperture 238, a guide cavity 240, and a plurality of threaded bores constituting a mounting pattern 242. The aperture 238 is in communication with the guide cavity 240. The aperture 238 receives the stop adjust rod 224. The guide cavity 240 contains the equalize block 226. The mounting pattern 242 mates with the mounting pattern 31 on the press body 12. The mounting patterns 31, 242 include an ISO Standard 125 millimeter diameter Weld Gun Mounting Pattern. The mounting pattern 31 is machined through the side of the press body 12. This enables the equalizer assembly 212 to be mounted on either the right hand or left hand side of the press body 12. Additionally, for ease of assembly, the mounting pattern 242 is provided such that fasteners can be installed from the opposite side of the press body 12 from which the equalizer assembly 212 is being mounted.
The lower 230 and upper 232 stop collars are disposed on opposite ends of the stop adjust rod 224. The lower 230 and upper 232 stop collars include steel rings and a screw. The screws can be loosened and/or tightened to position the stop collars 230, 232 as desired on the stop adjust rod 224. Such positioning enables a user to adjust the stroke of the press 10 relative to the equalize mount block 228 of the equalizer assembly 212. Additionally, the stop adjust rod 224 may be threadably adjusted relative to the equalize block 226 to adjust the stroke of the ram assembly 16 of the press 10.
The plurality of slide brackets 234 includes four slide brackets 234 a-234 d. The slide brackets 234 each include channels 244. The slide brackets 234 are mounted to a backside of the equalize mount block 228 via threaded fasteners 235. The plurality of slides 236 include two slides 236 a and 236 b. The two slides 236 a and 236 b are fixedly attached to the press body 12 via fasteners 237. The first slide 236 a is slidably engaged by the channels 244 of slide brackets 234 a and 234 b. The second slide 236 b is slidably engaged by the channels 244 of slide brackets 234 c and 234 d. As the actuator 214 operates to translate the piston 222 within the cylinder 220, the press 10 translates linearly relative to the equalize mount block 228 between the first position (shown in FIG. 12) and the second position (shown in FIG. 13).
The sensor 218 includes a sensor body 246, an upper probe 248, and a lower probe 250. The sensor body 246 is disposed on a side of the equalize mount block 228 adjacent the guide cavity 240. The upper 248 and lower 250 sensor probes extend through the sidewall of the equalize mount block 228 and have ends 248 a, 250 a disposed substantially flush with a plane common to the peripheral edges of the lower 230 and upper 232 stop collars. In an exemplary embodiment, the upper 248 and lower 250 sensor probes include magnetic devices operable to detect the presence of either the lower stop collar 230 or the upper stop collar 232. In either event, it should be appreciated that the sensor 218 remains fixed in a single position on the equalize mount block 228, regardless of the position of the stop collars 230, 232. It should further be appreciated that the sensor 218 is operable to output a first signal when detecting the presence of one of the stop collars 230, 232 and output a second signal when the sensor fails to detect the presence of a stop collar 230, 232.
FIGS. 15-18 depict an alternate embodiment ram assembly 300. Ram assembly 300 is substantially similar to ram assembly 16, previously described. As such, like components will retain the reference numerals previously introduced. Ram assembly 300 includes ram base 110 threadingly engaged with a press ram 301. A biasing mechanism 302 allows incremental adjustment of the overall length of ram assembly 300 by rotating press ram 301 relative to ram base 110.
Biasing mechanism 302 includes a plurality of balls 304, a retainer 306 and a coil spring 308. Coil spring 308 is positioned within a bore 310 of press ram 301. A bore 312 interconnects bore 310 and a punch holder bore 314. The remaining lower portion of press ram 301 is substantially similar to the lower portion of press ram 112 and is not depicted in FIG. 17. As in the previous embodiment, fastener 135 couples holder 115 (FIG. 6) to the press ram.
The retainer 306 is a substantially cylindrical member having a bore 316 axially extending therethrough. A counterbore 318 is in communication with bore 316 and is sized to receive coil spring 308. The retainer 306 includes an end face 320. A plurality of recesses 322 are positioned on end face 320 and circumferentially spaced apart from one another. The recesses 322 are sized to receive a portion of balls 304 and allow a remaining portion of each ball to protrude outwardly from end face 320. As mentioned earlier, ram base 110 includes eight circumferentially spaced apart indentations 122 positioned on the end surface 120. Each of the indentations 122 are sized to receive a portion of the balls 304. One skilled in the art will appreciate that biasing mechanism 302 functions substantially similarly to biasing mechanism 114 in that eight distinct rotational positions exist between ram base 110 and press ram 301.
Retainer 306 is positioned within bore 310 and is free to axially translate within the bore. A series of flats 324 are formed on an outer surface of retainer 306. Flats 324 engage correspondingly flat wall portions 326 to restrict rotation of retainer 306 relative to press ram 301. In operation, coil spring 308 biasedly loads retainer 306 and balls 304 into engagement with ram base 110 to somewhat restrict relative rotational movement between ram base 110 and press ram 301. As mentioned previously, the overall length of ram assembly 300 may be adjusted by rotating press ram 301 relative to ram base 110 with sufficient force to overcome coil spring 308 and move balls 304 into the next set of indentations 122. Because ram base 110 includes eight equally spaced indentations, the exact change in overall length may be calculated knowing the thread pitch of the connection between ram base 110 and press ram 301 in view of a rotational angle of 450. In the embodiment disclosed, 450 of rotation changes the overall length of ram assembly 300 by approximately 0.004 inches.
Furthermore, the foregoing discussion discloses and describes merely exemplary embodiments of the present invention. One skilled in the art will readily recognize from such discussion, and from the accompanying drawings and claims, that various changes, modifications and variations may be made therein without department from the spirit and scope of the invention as defined in the following claims.

Claims

1. A press for translating a tool, comprising:

a press body defining a cavity;

a piston disposed within said cavity, said piston being pivotable between a first position and a second position, said piston including a trunnion defining a trunnion face and a plurality of pin recesses aligned on an arc;

a sensor pin disposed in one of said plurality of pin recesses substantially flush with said trunnion face; and

a sensor supported by said press body and substantially axially aligned with said trunnion, said sensor being operable to detect the presence of said sensor pin when said piston is in said first and second positions.

2. The press of claim 1 wherein said trunnion face further includes an arcuate slot surrounding said plurality of pin recesses.

3. The press of claim 1 wherein said plurality of pin recesses each include a threaded blind bore for receiving said sensor pin.

4. The press of claim 1 wherein said sensor is a proximity sensor having a sensing element disposed substantially flush with said trunnion face.

5. The press of claim 1 wherein said sensor includes a magnetic device and said sensor pin is constructed of a ferromagnetic material.

6. The press of claim 1 wherein said sensor is operable to output a first signal when said piston is in said first position and a second signal when said piston is in said second position.

7. The press of claim 1 wherein said trunnion further defines a substantially cylindrical bearing surface in sliding rotational engagement with said press body.

8. The press of claim 7 wherein said trunnion further includes a network of internal cavities in fluid communication with said bearing surface for containing and dispensing a lubricant thereto.

9. The press of claim 8 wherein said press body includes a first lubrication port in fluid communication with said network of internal cavities for injecting a lubricant therein.

10. The press of claim 1 wherein said press includes a first pneumatic port in communication with said cavity for selectively supplying pressurized fluid to one side of said piston.

11. A press for translating a tool, comprising:

a press body having a cavity;

a piston rotatably positioned within said cavity and moveable between a first position and a second position;

a press link including a first yoke and having a first leg defining a first aperture and a second leg defining a second aperture, wherein said second aperture includes a rotation limiting surface; and

a first link pin drivingly interconnecting said first yoke and said piston, said first link pin including:

a first end engaging said first aperture;

a body portion having a substantially cylindrical bearing surface rotatably engaging said piston;

a second end engaging said second aperture such that said rotation limiting surface prevents said first link pin from rotating relative to said first yoke; and

a network of internal cavities in fluid communication with said bearing surface, said network adapted to contain and dispense a lubricant to said bearing surface.

12. The press of claim 11 wherein a portion of said second aperture includes a curved wall portion and a substantially planar wall portion.

13. The press of claim 12 wherein a portion of said second aperture is substantially D-shaped.

14. The press of claim 13 wherein said second end of said first link pin is substantially D-shaped.

15. The press of claim 11 wherein said network of internal cavities includes an axial cavity and a plurality of radial cavities in fluid communication with said axial cavity.

16. The press of claim 11 wherein said press link further includes a second yoke opposite said first yoke.

17. The press of claim 16 further comprising a second link pin, wherein said second yoke includes a third leg defining a third aperture and a fourth leg defining a fourth aperture, said second link pin extending through said third and fourth apertures of said second yoke wherein said second link pin is prevented from rotating relative to said second yoke.

18. A press for translating a tool, comprising:

a first member drivingly coupled to an actuator, said first member being axially moveable between first and second positions in response to movement of said actuator, said first member including a first end surface having a plurality of circumferentially spaced apart detents;

a second member threadably engaging said first member, said first and second members defining an assembly having a length;

a plurality of retention members positioned between said first and second members, each retention member biasedly engaging one of said detents, thereby providing resistance to relative rotation between said first and second members, wherein said resistance to relative rotation may be overcome to adjust said length of said assembly.

19. The press of claim 18 wherein said second member includes a plurality of axially extending bores in receipt of said retention members.

20. The press of claim 19 further including a plurality of biasing members positioned within said bores between said retention members and said second member.

21. The press of claim 20 wherein said plurality of detents includes eight detents.

22. The press of claim 21 wherein said plurality of engaging members includes eight pins.

23. The press of claim 18 further including a press body and a strain gauge mounted to said press body, said strain gauge being operable to indicate an overload condition and provide a signal to discontinue the application of force by said actuator.

24. The press of claim 18 wherein said plurality of detents are equally spaced apart and aligned substantially in a circle.

25. The press of claim 18 wherein said second member includes an annular surface substantially parallel to and axially spaced apart from said first end surface, said annular surface including a plurality of bores alignable with said detents, said bores receiving at least a portion of said plurality of retention members.

26. The press of claim 18 wherein said plurality of retention members each include a first end having a longitudinal bore in receipt of a biasing member.

27. The press of claim 26 wherein said plurality of retention members each include a second end that is curved and received by said detents.

28. The press of claim 27 wherein said plurality of detents are conically shaped.

29. The press of claim 18 wherein one of said first and second members includes a marking on an outer surface thereof to provide a datum for said length of said assembly of said first and second members.

30. The press of claim 18 further including a retainer aligning said retention members in a spaced apart relation to one another.

31. The press of claim 30 wherein said retainer is axially translatable to allow said retention members to enter and exit said detents during adjustment of said length of said assembly.

32. The press of claim 31 further including a spring biasedly loading said retainer toward said first member.

33. The press of claim 32 wherein said first member includes eight equally spaced apart detents and said retainer aligns four retention members in an equally spaced apart relation.

34. The press of claim 30 wherein said retainer and said retention members are positioned within a cavity formed in one of aid first and second members.

35. A press for translating a tool, comprising:

a press body;

an actuator supported by said press body;

a ram assembly drivingly coupled to said actuator, said ram assembly linearly moveable in an advancing direction and a retracting direction;

a tool assembly coupled to an end of said ram assembly opposite said actuator; and

a quick release mechanism including a pin removably attaching said tool assembly to said ram assembly wherein a load being transferred to said tool assembly during movement in said advancing direction bypasses said pin, said tool assembly being disconnectable from said ram assembly by removal of said pin without the use of hand tools.

36. The press of claim 35 wherein said tool assembly includes a punch having a transverse aperture extending therethrough.

37. The press of claim 36 wherein said ram assembly includes an elongated tube having a pair of transverse apertures substantially aligned with said transverse aperture in said punch.

38. The press of claim 37 wherein said pin extends through said apertures in said punch and said elongated tube to limit axial and rotational movement of said punch relative to said elongated tube.

39. The press of claim 38 wherein a clearance exists between said pin and said punch aperture such that load travels through said punch to said ram assembly without loading said pin during movement of said ram assembly in said advancing direction.

40. The press of claim 37 further including a stripper at least partially surrounding said punch, said stripper being biased in a direction away from said elongated tube.

41. The press of claim 40 wherein said stripper includes a pair of spaced apart axially extending slots in receipt of said pin.

42. The press of claim 41 wherein said ram assembly further includes an annular collar threadably engaging said elongated tube to retain a spring in a cavity of said elongated tube, said spring being operable to provide said biasing load to said stripper.

43. The press of claim 42 wherein said annular collar includes a pair of axial slots aligned to receive said pin.

44. A press for translating a tool, comprising:

a press body having an upper jaw and a lower jaw;

an actuator supported by said press body;

a ram assembly drivingly coupled to said actuator and slidably positioned within said upper jaw;

a lower tool assembly supported by said lower jaw of said press body axially below said ram assembly, said lower tool assembly including a shoulder portion engaging said lower jaw and a shank portion including a transverse aperture engaging an axial bore extending through said lower jaw; and

a quick release mechanism including a pin removably attaching said lower tool assembly to said press body, said lower tool assembly being disconnectable from said press body by removal of said pin without the use of hand tools.

45. The press of claim 44 wherein said lower jaw portion defines a first axial bore receiving said lower tool assembly.

46. The press of claim 45 wherein said lower tool assembly includes a tool holder positioned in said first axial bore.

47. The press of claim 46 wherein said press body defines a transverse bore extending through said first axial bore substantially aligned with said transverse aperture in said shank portion of said tool holder.

48. The press of claim 47 wherein said press body further includes a second axial bore substantially parallel to said first axial bore and intersecting said transverse bore, said second axial bore receiving a locking portion of said quick release mechanism.

49. The press of claim 48 wherein said detent pin is disposed through said transverse bore and transverse aperture, thereby restricting relative rotational displacement of said tool assembly and press body.

50. The press of claim 49 wherein said locking portion of said quick release mechanism includes a spring biased detent retained on said pin.

51. The press of claim 47 wherein said tool holder includes an axial recess for receiving a tool.

52. The press of claim 51 wherein said tool includes a die for forming a workpiece compressed between said ram assembly and said lower assembly.

53. The press of claim 52 wherein said tool holder further includes a fastener bore for receiving a fastener to secure said tool in said tool holder, said fastener bore extending substantially coaxially to and in communication with said axial recess.

54. A press for translating a tool, comprising:

a press body;

a first actuator coupled to said press body;

a tool assembly coupled to said first actuator and supported by said press body for drivingly engaging a workpiece;

a second actuator attached to said press body and adapted to translate said press body relative to a mounting member;

a guide assembly interconnecting said mounting member and said press body, said guide assembly including a translation limiting mechanism operable to adjust a range of translation of said press body between various extended and retracted positions; and

a sensor fixedly attached to said guide assembly and operable to detect the position of said press body when located at said extended and retracted positions.

55. The press of claim 54 wherein said actuator includes a cylinder fixedly attached to said press body and a piston fixedly attached to said mounting member.

56. The press of claim 55 wherein said mounting member slidably engages a stop adjust rod, wherein said stop adjust rod is fixedly attached to said press body.

57. The press of claim 56 wherein said translation limiting mechanism includes a stop collar selectively positioned on said stop adjust rod.

58. The press of claim 57 wherein said translation limiting mechanism further includes a screw for selectively fixing said stop collar to said stop adjust rod in said plurality of positions.

59. The press of claim 58 wherein said sensor includes a sensing element disposed in a plane substantially parallel to a peripheral edge of said translation limiting mechanism.

60. The press of claim 59 wherein said sensing element is a magnetic device and said stop collar is constructed of a ferromagnetic material.