1. Field of the Invention
The present invention relates to measuring apparatuses, and particularly to an apparatus and method for measuring kinetic parameters of a punch during press molding.
2. Description of Related Art
In a typical press molding machine, a punch is used to insert into and engage with molding die, so as to make through holes or blind holes in a workpiece. Initially, the workpiece is placed on a molding surface of molding die having a predetermined concave shape. Next, the workpiece is pressed by a punch having a shape corresponding to the concaved portion. Often the punch may be displaced along the molding surface of the molding die during press molding. As a result, the accuracy of the press-molded product may be affected.
What is needed is an apparatus and method for determining the position of the punch during press molding.
An exemplary apparatus and method for measuring kinetic parameters of a machining tool within a press molding machine includes two magnets and two electrical conductors attached to a machining tool. The two magnets are fixed for producing two magnetic fields that are at an angle to each other. The two electrical conductors are connected to a controller to form two closed loops respectively. Each electrical conductor is located in a corresponding magnetic field and is unparallel to the direction of the corresponding magnetic field. Upon the condition that the machining tool deviates from its axial path, voltages are induced across the two electrical conductors. The controller receives the induced voltages, and determines a velocity of the machining tool's deviation from the axial path.
Other novel features and advantages will become more apparent from the following detailed description of preferred and exemplary embodiment when taken in conjunction with the accompanying drawings, in which:
Referring to
The fixing device 10 has a hollow cylindrical main body 16 for receiving the punch 30, two rectangular projecting portions 12 and 14 protruding from the main body 16. The conductive wires ab and cd are embedded in the projecting portions 12 and 14 respectively. The projecting portion 12 is perpendicular to the projecting portion 14. In this exemplary embodiment, the conductive wires ab and cd are parallel to the axial direction of the punch 30. The magnet 22 has a north pole 220, a south pole 222, and a bottom part 224 connecting the north pole 220 to the south pole 222 to form a recess. The magnet 24 has a north pole 240, a south pole 242, and a bottom part 244 connecting the north pole 240 to the south pole 242 to form another recess. In this exemplary embodiment, the magnets 22 and 24 are suspended firmly from a ceiling of a worktable of the press molding machine maintained in a fixed position. The projecting portions 12 and 14 are non-contactingly located in the recesses of the magnets 22 and 24 respectively and move with the punch 30. North poles 220, 240 of the magnets 22 and 24 face each other.
Referring to
In use, when the punch 30 moves along its path, it may deviate from its axial direction, the conductive wires ab and cd move in the magnetic fields B1 and B2 respectively, and voltages are induced across the wires ab and cd. The AD converters 40 and 50 convert the voltages from analog values to digital values, respectively. The controller 60 receives the digital values of the voltages and calculates the kinetic velocity of the conductive wires ab and cd.
Referring to
E1 and E2 are respectively the strength of the magnetic fields B1 and B2
L1 and L2 are respectively the length of the conductive wires ab and cd that are inside and perpendicular to the magnetic fields B1 and B2
α is the angle between a deviating direction of the punch 30 and the direction of the magnetic field B1
β is the angle between the deviating direction of the punch 30 and the direction of the magnetic field B2
e1 and e2 are the digital values of the induced voltages received by the controller 60.
In this exemplary embodiment, the equations pre-set in the controller 60 can be changed according to the user's needs. Given that the magnets are offset by ninety degrees, β is equal to 90°−α (graphic example shown in
The displacements of the punch 30 along the x-axis and y-axis can be calculated by the controller 60 according to the x-axis component vx and the y-axis component vy respectively. The position of the punch 30 and a workpiece to be punched by the press molding machine can be adjusted by the controller 60 according to the displacements of the punch 30 along the x-axis and y-axis respectively. Therefore, the press molding machine works more accurately.
The foregoing description of the exemplary embodiments of the invention has been presented only for the purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to explain the principles of the invention and their practical application so as to enable others skilled in the art to utilize the invention and various embodiments and with various modifications as are suited to the particular use contemplated. Alternative embodiments will become apparent to those skilled in the art to which the present invention pertains without departing from its spirit and scope. Accordingly, the scope of the present invention is defined by the appended claims rather than the foregoing description and the exemplary embodiments described therein.
Number | Date | Country | Kind |
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200810300418.9 | Feb 2008 | CN | national |