Abrading – Abrading process – Glass or stone abrading
Utility Patent
1999-04-12
2001-01-02
Butler, Rodney A. (Department: 3725)
Abrading
Abrading process
Glass or stone abrading
C451S255000, C451S256000
Utility Patent
active
06168505
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a polishing machine for spectacle lense edges with a driven grinding wheel, a driven spectacle lense securing shaft moveable relative to the grinding wheel in two substantially perpendicularly arranged axes, and a grinding chamber enclosing the grinding wheel and the spectacle lense securing shaft.
Polishing machines for spectacle lense edges of the aforementioned kind are known, for example, from patents 36 08 957 and 43 09 101 of the instant applicant.
The polishing machine for spectacle lense edges described in the German patent 36 08 957 is of the kind in which a grinding chamber is fastened to a machine support frame, a spectacle lense securing shaft is guided with its drive through the grinding chamber, in which also a grinding wheel is arranged which is guided in a sealed manner out of the grinding chamber and, outside of the grinding chamber, is arranged on a cross-slide rest together with its drive so that it can be moved in this manner radially as well as axis-parallel to a spectacle lense blank arranged on the spectacle lense securing shaft.
In this polishing machine for spectacle lense edges, an increased spacial requirement results from this arrangement and, moreover, the cross-slide rest guides are highly precise components which are rather expensive to manufacture and are sensitive with regard to soiling. This is also true for a polishing machine for spectacle lense edges disclosed in French patent application 2 553 323 in which only the grinding wheel and its drive motor are arranged on a carriage guide while an arm that supports the spectacle lense securing shaft and also supports the grinding chamber, in which the spectacle lense blank arranged on the spectacle lense securing shaft as well as the grinding wheel are arranged, so that it is pivotable only about a horizontal axis.
In contrast, the polishing machine for spectacle lense edges according to the German patent 43 09 101 is less complicated in its manufacture because the grinding wheel with its drive is stationarily arranged on a machine support and the spectacle lense securing shaft is arranged so as to be moveable relative thereto at a pivotable upper machine part that can be vertically reciprocated and pivoted about a vertical axis. The column guide action can be realized precisely and in a stable fashion with simple means. However, in this known polishing machine for spectacle lense edges, despite the covers provided for the grinding wheel and the spectacle lense blanks secured at the spectacle lense securing shaft there is a risk of soiling of sensitive machine parts because of the cooling liquid which is sprayed into the area between the grinding wheel and the spectacle lense blank and is thrown off the grinding wheel together with the ground off material of the spectacle lense because between the machine support comprising a depression in which the grinding wheel is arranged and the upper machine part with the spectacle lense securing shaft an unavoidable gap is present through which the cooling liquid can penetrate into the area of the guides for the upper machine part.
It is a partial object of the invention to design a polishing machine for spectacle lense edges similar to that of German patent 43 09 101 such that with a simple construction it provides at least the same protection against splashing cooling liquid as the polishing machine for spectacle lense edges according to the German patent 36 08 957. A further partial object of the invention is to provide suitable drives for the lifting and lowering movement as well as the pivot movement that are suitable for a CNC control in conjunction with a polishing machine for spectacle lense edges of a kind similar to the kind disclosed in the aforementioned patent. Finally, the invention has a further partial object in that for a polishing machine for spectacle lense edges similar to the kind disclosed in the aforementioned patent an advantageous arrangement of a device for controlling the grinding process is to be suggested.
SUMMARY OF THE INVENTION
As a solution to the first partial object, a polishing machine for spectacle lense edges is suggested having a grinding wheel which is arranged together with its drive on a machine support supporting a guide column, further having a spectacle lense securing shaft arranged with its drive on the upper machine part so as to be linearly moveable up and down as well as pivotable about an axis of the guide column which is perpendicular to and spaced from the grinding wheel and spectacle lense securing shaft axis, further having a grinding chamber surrounding the grinding wheel and the spectacle lense securing shaft that seals against the cooling liquid which is thrown off the grinding wheel, whereby the grinding chamber is arranged at the upper machine part and has a cooling liquid drain guided into the machine support, and having a moveable seal between the grinding chamber and a grinding spindle.
Since this grinding chamber sealingly surrounds the spectacle lense securing shaft as well as the grinding wheel, the cooling liquid which is thrown off the grinding wheel cannot enter the area of drives and guides whereby, however, the spectacle lense securing shaft is easily accessible from the exterior via a pivotable lid at the grinding chamber and whereby the grinding process can be easily observed through the pivot cover when it is transparent.
In this embodiment, the guide column thus provides a linear guiding action for the up and down movement of the upper machine part as well as a pivot guiding action about the axis of the guide column. By arranging the grinding chamber, which tightly encloses the spectacle lense securing shaft and the grinding wheel at the upper machine part, the cooling liquid which is thrown off the grinding wheel is safely kept away from contacting the column guide and the drive for the grinding wheel.
In another embodiment, the grinding chamber and the spectacle lense securing shaft with its drive can be arranged above the grinding wheel and its drive at a machine support, while the grinding wheel and its drive are arranged on a pivotable arm which is moveably supported at a vertical guide column so as to move up and down and to pivot about the axis of the guide column whereby its grinding spindle is guided sealingly in the grinding chamber.
In this embodiment, the grinding chamber is thus also fastened at the upper machine part and surrounds the spectacle lense securing shaft and the grinding wheel. The grinding wheel in this case performs the relative movement to the spectacle lense securing shaft and to the spectacle lense blank clamped thereat without requiring any changes in regard to the seals and the effectiveness of the seals relative to the drives and the guides.
The sealing action between the grinding spindle and the grinding chamber can be realized in the two embodiments by a simple bellows which allows sufficient movability for the relative movements between the grinding chamber and the grinding spindle.
In order to be able to remove the grinding dust from the grinding chamber, it is possible to orient a cooling liquid stream into the area between the spectacle lense blank and the surface of the grinding wheel which, for example, consists of fresh water or cooling water which is recirculated and filtered. In both cases it is advantageous to provide in the lower area of the grinding chamber a cooling liquid drain extending into the machine support which extends into a funnel-shaped collecting receptacle at the machine support from where the collected cooling liquid flows into a collecting tank. Optionally, the liquid drain can also be sealed relative to the machine support whereby this seal is also comprised of a bellows. When the cooling liquid is fresh water, the cooling liquid draining from the cooling liquid drain is guided into a separator for removing the grinding dust and is then introduced into the waste water system. When the cooling liquid is recirculated, the cooling liquid is taken up by a cooling liquid p
Butler Rodney A.
Robert W. Becker & Associates
Wernicke & Co. GmbH
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