Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B30—PRESSES
  • B30B—PRESSES IN GENERAL
  • B30B1/00—Presses, using a press ram, characterised by the features of the drive therefor, pressure being transmitted directly, or through simple thrust or tension members only, to the press ram or platen
  • B30B1/18—Presses, using a press ram, characterised by the features of the drive therefor, pressure being transmitted directly, or through simple thrust or tension members only, to the press ram or platen by screw means
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B30—PRESSES
  • B30B—PRESSES IN GENERAL
  • B30B1/00—Presses, using a press ram, characterised by the features of the drive therefor, pressure being transmitted directly, or through simple thrust or tension members only, to the press ram or platen
  • B30B1/18—Presses, using a press ram, characterised by the features of the drive therefor, pressure being transmitted directly, or through simple thrust or tension members only, to the press ram or platen by screw means
  • B30B1/186—Control arrangements
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B30—PRESSES
  • B30B—PRESSES IN GENERAL
  • B30B15/00—Details of, or accessories for, presses; Auxiliary measures in connection with pressing
  • B30B15/12—Clutches specially adapted for presses

Definitions

• This invention relates to a fastener press which utilizes electric servo motors for precise ram position control. More specifically, the present invention relates to a servo motor driven ram having separate high- force and low- force drive motors using a clutch-type drive mechanism and regulated by a controller. BACKGROUND OF THE INVENTION
• presses utilize a two-motor servo system to control velocity, position, and force of the press ram to install fasteners to the proper force or distance depending on the application.
• a high torque drive is engaged to drive the ram to the desired force or position. After insertion the high speed motor returns the ram to the home position.
• a fastener press for example a Pemserter Series 3000 manufactured and sold by Penn Engineering and Manufacturing Corp., as shown in Figure 1, utilizes a bidirectional over-running clutch through which high force ram drive power passes.
• the clutch is controlled by relative motion of two separate motor drives as will be described in detail below.
• Bidirectional over-running clutches are commercially available components that consist of a regular, polygon-shaped inner hub surrounded by rollers encased in an outer hub as shown in Figure 3.
• the inner and outer hubs are connected to separate shafts.
• the inner hub shaft can drive the outer hub shaft in either a clockwise or counterclockwise direction if the inner hub shaft speed of rotation is greater than the outer hub.
• Figure 1 is a front left isometric view of a ram press utilizing the invention.
• FIG. 2 is a diagram showing the major components of the invention.
• Figure 3 is a top front left isometric view of the bidirectional clutch of the invention.
• Figure 4 is a elevation cross-sectional view of the bidirectional clutch of the invention.
• Figure 5 is a graph showing the pressing profile of one embodiment of the invention depicting the speed of the ram over time. DESCRIPTION OF THE PREFERRED EMBODIMENT
• a ram press 4 employing the invention which includes a c-shaped frame 1 that supports an anvil 2 that is reciprocally impacted by ram 3.
• major components of the invention are disclosed which comprise a frame that supports basic mechanical components of the invention that comprise a high-speed mechanical actuator and a high-torque motor.
• a screw drive which may be operated in either direction by either the high-speed or low-speed motor means.
• a bidirectional self-disengaging clutch is connected to the high torque motor means which includes a motor/gear reducer combination.
• a programmable logic controller regulates operation of the two motors and thus movement of the ram by way of the screw drive.
• the bidirectional clutch is connected to the main shaft of the screw drive by way of a timing belt.
• the logic controller regulates the movement of the ram according to a pressing profile that will be described in more particularity with regard to Figure 5.
• the press ram is moved by a screw actuator whose shaft is coupled directly to the high speed motor means in this embodiment being the commercially available device generally referred to as an electromechanical actuator.
• the device incorporates a screw drive mechanism so that its internal shaft is reciprocated in a range of motion between extended and retracted positions. That drive shaft is also coupled to the output of the above-described clutch by way of a gear belt drive.
• the input shaft of the clutch is coupled to the high torque motor.
• the clutch is operated by the relative speeds of separate brushless DC or AC servo motors that are regulated by a controller.
• Each motor has a feedback device such as an encoder or resolver and an additional encoder is attached to the main actuator shaft so that the relative position of the ram is known regardless of which motor is operating the ram.
• One motor provides a high-speed drive while the second motor is a high-torque drive which is an integrated servo gear motor with a 10 to 1 ratio.
• the high- torque motor means has its own encoder for communication and control and its output shaft is coupled to the high-speed motor's drive shaft through the above-described high-torque clutch, transmitted there by a belt.
• the high-torque motor can rotate the screw actuator when the clutch is engaged. Engagement of the clutch is achieved by regulating the speeds of the motors to switch ram operation from one motor to the other when the other is running faster.
• FIG. 4 is a cross- sectional view of the bidirectional clutch describing greater details of its structure.
• the outer hub shaft carries the output of the clutch and is connected to the high speed motor shaft by way of a belt drive as depicted in Figure 2.
• the inner hub shaft is connected to a high torque output of the gear motor. Operation
• the above movements are regulated by a controller which determines the speeds of the high speed and high torque motors which, in combination with the clutch of Figure 2 interposed between the high torque motor and the screw actuator, follows a prescribed pressing profile that determines the motion of the ram.
• Figure 5 represents a typical pressing profile.
• the X axis represents time in seconds and the Y axis represents speed (inches per second)
• the dotted lines 9 indicate the typical motion of the high torque motor and the solid lines 8 represent the motion of the high speed motor as it relates to ram movement.
• the first move is to start the high torque motor prior to starting the high speed motor. This move insures that the clutch will disengage when the high speed motor overtakes the high torque motor.
• the high speed motor When the solid line crosses the dotted line (reading from left to right) the high speed motor overtakes the high torque motor and is then in control of the ram. The high torque motor then decelerates and stops during the high speed move. At the mid point of the graph the high speed move (solid line) is approaching the pressing position. At this time the high torque motor starts accelerating while the high speed motor is decelerating. When the dotted line overtakes the solid line the high torque motor is in control and the pressing sequence begins. Once pressing is complete the high torque motor decelerates. On the return stoke after pressing, the high torque motor is started in reverse and begins to accelerate. The high speed motor then starts and begins to accelerate at a faster rate. When the solid line crosses the dotted line the high speed motor overtakes the high torque motor and is in control. The high speed motor finishes the move and decelerates to a stop. The cycle is complete and ready for the next cycle.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Press Drives And Press Lines (AREA)
• Control Of Presses (AREA)
• Presses And Accessory Devices Thereof (AREA)

Priority Applications (5)

Applications Claiming Priority (2)

Publications (2)

Family

ID=42198711

Family Applications (1)

Country Status (6)

Families Citing this family (5)

Family Cites Families (13)

• 2008
  • 2008-11-06 MX MX2010002778A patent/MX2010002778A/es active IP Right Grant
  • 2008-11-06 EP EP08876907A patent/EP2432671A4/en not_active Withdrawn
  • 2008-11-06 CN CN200880116458.6A patent/CN101970271B/zh not_active Expired - Fee Related
  • 2008-11-06 MY MYPI2010001090A patent/MY153347A/en unknown
  • 2008-11-06 WO PCT/US2008/082636 patent/WO2010059147A2/en not_active Ceased
  • 2008-11-06 JP JP2010539553A patent/JP5222956B2/ja not_active Expired - Fee Related

Non-Patent Citations (1)

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