Abrading – Precision device or process - or with condition responsive... – With indicating
Reexamination Certificate
1999-02-08
2001-06-19
Eley, Timothy V. (Department: 3723)
Abrading
Precision device or process - or with condition responsive...
With indicating
C451S057000, C451S065000, C483S033000, C483S054000
Reexamination Certificate
active
06247999
ABSTRACT:
FIELD OF THE INVENTION
A synthetic resin component of a vehicular lighting fixture, such as a lamp body or a front lens, is generally formed using a mold. The present invention relates to a mechanism and a method for automatically exchanging polishing tools in a mold polishing device used to polish a mold, particularly a molding surface or a parting surface of a mold, which is used for forming a synthetic resin product such as a lamp body or a front lens.
BACKGROUND OF THE INVENTION
In order to produce a mold for forming a synthetic resin product such as a lamp body or a front lens, the mold is first cut or cast into a predetermined shape, and a molding surface or a parting surface of the mold is then subjected to electric spark machining. Finally, a polishing tool is used to mirror-finish the molding surface or the parting surface. Although a polishing process using a polishing tool may be performed manually, a great deal of skill is required to properly flat-finish a work surface. Moreover, such a polishing process requires time-consuming operations. Therefore, a polishing robot has recently been employed to enhance polishing precision and reduce the time required for the polishing process.
More specifically, a polishing tool is mounted on a spindle at a leading end of an arm of the polishing robot. The polishing tool is set in rotation and pressed against a work surface of the mold and caused to run along the work surface, which is thereby polished.
In order to polish the work surface, a plurality of polishing tools of different grits (roughnesses) ranging from coarse to fine are prepared in advance. After a polishing tool of a certain grit has been used, another polishing tool of a finer grit is mounted on the spindle at the leading end of the arm of the robot. By thus exchanging polishing tools, the polishing operation is performed.
However, according to the aforementioned conventional polishing process, the polishing tool must be manually mounted on and removed from the spindle at the leading end of the arm of the polishing robot. That is, the operation of exchanging polishing tools is performed manually. Therefore, every time polishing tools are exchanged, the polishing process is interrupted. Consequently, it takes a long time to finish the polishing process.
Furthermore, the polishing tool is coupled to the spindle at the leading end portion of the arm of the polishing robot by means of a fastener, specifically, a collet chuck mechanism. In order to exchange polishing tools, the following operations must be performed. First, a wrench is used to loosen the chuck mechanism, and the previously used polishing tool is removed from the leading end portion of the spindle. A new polishing tool is mounted on the spindle, and the chuck mechanism is tightened.
The fact that it takes such a long time to exchange polishing tools also contributes to prolongation of the polishing process. Further, in order to exchange polishing tools, the operator has to stop other ongoing operations temporarily. Another problem is that unless an operator is present at the site where polishing tools are exchanged, the polishing process cannot be carried out. The fact that polishing tools are exchanged manually results in a decrease in the productivity in manufacturing molds.
SUMMARY OF THE INVENTION
The present invention has been made in the light of the aforementioned problems of the prior art. It is thus an object of the present invention to provide a mechanism and method for automatically exchanging polishing tools in a mold polishing device that can automatically exchange polishing tools.
In order to achieve the above-described and other objects, a mechanism for automatically exchanging polishing tools in a mold polishing device according to the present invention is constructed as follows. A polishing tool, which is mounted on a spindle provided on an arm of a multi-axis mold polishing robot and which rotates together with the spindle, is pressed against and moved along the work surface. A T-shaped tool holder, which has a pair of left and right horizontal latch pins protruding from a vertical rod that is coaxially integrated with the spindle, is provided at a leading end portion of the spindle. The polishing tool is provided with a pair of notches allowing the horizontal latch pins to be engaged therewith in a press-fitted manner and to be forcibly withdrawn upward therefrom. A tool stand and a tool removal stand are provided in proximity to a mold setting area to which a mold to be polished is fixed. A plurality of polishing tools are arranged at predetermined intervals on the tool stand, with the notches of the polishing tools facing upward. A horizontal slot, whose width is larger than the outer diameter of the vertical rod of the tool holder but smaller than the outer diameter of the polishing tool, is formed in the tool removal stand. The horizontal latch pins are press-fitted from above into the notches of a predetermined one of the polishing tools in the tool stand so as to mount the polishing tool to the tool holder. The horizontal latch pins are passed upward from a lower portion of the horizontal slot of the tool removal stand so as to remove the polishing tool from the tool holder.
The arm of the multi-axis robot is lowered from above towards a predetermined one of the polishing tools in the tool stand, whereby the horizontal latch pins of the tool holder are press-fitted into the notches of the polishing tool, which is then mounted on the tool holder. The arm of the multi-axis robot is raised such that the horizontal latch pins are passed upward from a lower portion of the horizontal slot of the tool removal stand. Thereby, the horizontal latch pins are forcibly withdrawn from the notches, and the polishing tool is removed from the tool holder. Thus, with a simple structure, the polishing tool can be mounted on and removed from the tool holder automatically.
Further according to the present invention, there may be provided a T-shaped cross bar portion including the horizontal latch pins of the T-shaped tool holder tiltably pin-jointed with the vertical rod. While the horizontal latch pins are in engagement with the notches of the polishing tool, the tool holder cooperates with the notches to constitute a universal joint.
The polishing tool, which is coupled to the spindle through the universal joint that is composed of the tool holder and the notches, can always move along the work surface stably.
Still further according to the present invention, the polishing tool may be composed of a polishing member holding ring that is cylindrically shaped and made of synthetic resin. A polishing member is held by a lower end portion of the polishing member holding ring. The notches, which are opposed to each other, are formed in a side wall of the polishing member holding ring. A necking portion, whose width is smaller than an outer diameter of the latch pins, is formed in each of the notches on a side where the latch pins are press-fitted. A latch pin guide portion of the necking portion has a V shape.
In the polishing member holding ring made of synthetic resin, as the horizontal latch pins are press-fitted into or forcibly withdrawn from the notches, the necking portion is elastically deformed and widened. Thus, the horizontal latch pins can be press-fitted into and withdrawn from the notches smoothly.
Furthermore, the V-shaped latch pin guide portion causes the horizontal latch pins to slide towards the notches so that the horizontal latch pins can be press-fitted into the notches easily, and also causes the horizontal latch pins to slide away from the notches so that the horizontal latch pins can be withdrawn from the notches easily.
The tool holder is solidly coupled to the spindle by means of a fastener. A pair of chamfers, which correspond to the horizontal latch pins and are designed to detect and determine a circumferential position of the tool holder, are provided in an outer peripheral surface of an outer cylinder portion of the fastener.
The chamfers provided in the outer peripher
Eley Timothy V.
Koito Manufacturing Co. Ltd.
Sughrue Mion Zinn Macpeak & Seas, PLLC
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