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.
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.
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.
The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:
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
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 20a, 20b and a semi-circumferential outer wall 20c. The radial walls 20a, 20b 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
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 76b. The arched surface 76b 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 64a of upper yoke 54 engages rotation limiting surface 76a 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 80a and a plurality of radial bores 80b in fluid communication with one another. The radial bores 80b 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 84a and an arched surface 84b. The arched surface 84b 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 72a, 84a 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 84b 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
The proximity sensor 44 includes a sensor body 102, a first sensor probe 104, a second sensor probe 106, and a sensor pin 108 (
With reference now to
The ram base 110 includes a substantially cylindrical member disposed in the ram bore 21 of the press body 12 (shown in
The press ram 112 includes a first end 112a and a second end 112b. The first end 112a 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 112b includes a tool bore 130, a pair of transverse apertures 132a, 132b, and a marking 134. A fastener bore 133 interconnects bore 130 with bore 124. The internal threaded portion 126 of the first end 112a 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 138a and a second end 138b. The first ends 138a include longitudinal bores receiving the biasing members 140, as shown in
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
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 132a, 132b in the press ram 112. The tool portion 162 is adapted to engage a workpiece.
The stripper 146 includes a shoulder portion 146a and a sleeve portion 146b. The shoulder portion 146a includes a hollow cylindrical member defining a pair of vertical slots 164. The sleeve portion 146b 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 132a, 132b 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.
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 180a 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
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.
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 226a. The stop adjust rod 224 is a substantially cylindrical elongated member having an external thread over its entire length 224a threadably engaging the threaded bore 226a 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 234a-234d. 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 236a and 236b. The two slides 236a and 236b are fixedly attached to the press body 12 via fasteners 237. The first slide 236a is slidably engaged by the channels 244 of slide brackets 234a and 234b. The second slide 236b is slidably engaged by the channels 244 of slide brackets 234c and 234d. 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
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 248a, 250a 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.
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
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.