Patent Grant
6871378
The present invention relates to the washing and drying of aluminum laps used in the processing of ophthalmic lenses and, more particularly, to an automated lap washer rack system structure having an enclosure containing a washing and a drying chamber through which special mounting trays, removably attached to a tabletop style conveyor, carry aluminum laps through first the washing and then the drying chambers.
Aluminum laps, used for the processing of ophthalmic lenses, are generally made of bar stock aluminum ranging in diameter from 2.5 to 3.5 inches. Laps weigh approximately one pound and have one to two convex curves on the topside and a flat grooved bottom. They have an indefinite life and are used continuously to hold special pads designed to smooth and polish ophthalmic lenses. The polishing process is accomplished in two steps, “fining” and “polishing”. The fining process accomplished using a cylinder surface machine, uses a paper-like material typically coated with silicon carbide which removes material from the lens until it conforms to the convex shape of the lap. The polishing step replaces the fining pad with a soft woven velveteen backed pad which is impregnated with aluminum oxide polish to produce a clear transparent finish on the lens.
When polishing is complete, the lap is unclean and must be washed before the aluminum oxide dries and becomes difficult to remove. Washing laps by hand is laborious and time consuming and, in a large lens production facility, is counter-productive. The present invention facilitates the cleaning of large numbers of laps in an efficient and consistent manner as will be described in the following description and in the drawings annexed hereto.
In a preferred embodiment, the present invention provides an efficient, enclosed, and automatic means for conveying aluminum laps through a washing and drying cycle.
It is a further object of the invention to provide a conveyor means for carrying aluminum laps through the cleaning process.
It is a further object of the invention to provide trays for holding aluminum laps as they proceed through the cleaning cycle.
It is a further object of the invention to provide durable rotating brushes for cleaning the upper surface of aluminum laps and directed jets of water/air for cleaning the bottom of the laps.
It is a further object of the invention to provide a safety cut off switch.
It is a further object of the device to provide adjustable delivery means for both air and water.
It is a further object of the invention to provide filtration means for the efficient recycling of cleaning fluids used in the cleaning process.
The present invention is constructed in a unique assembly of components which are generally available commercially and to one skilled in the art the following parts list and the annexed drawings and description would serve to enable the successful construction of the invention.
Here follows the parts list to which, subsequent, more specific, and particular reference is made:
In the operation of the invention device, the following sequence is observed; Unclean aluminum laps are loaded upon the carrying tray of the invention. Each such tray carries 8 individual laps. The trays are made of UHMW polyethylene plastic and measure ½″ D×12″W×18″L. The trays and laps are placed upon a 4″ wide Bunting table top style conveyor which carries them into the washing system (through a slatted plastic apron curtain). The system is comprised of two separate chambers enclosed within a single rectangular box measuring 16″ D×14″ W×72″ L which is supported by four adjustable legs measuring approximately 32″ H.
The washing process takes place in the first chamber which is equipped with multiple water jets and a pair of rotating brushes. The brushes are made from nylon 66 material and measure 7″ in diameter and 10″ wide. The brushes rotate away from the incoming lap at a variable rate, normal rotation being at 125 rpm. A variable speed ¼ horsepower Lesson DC motor/gearbox drives the brushes via a synchronous tensioned drive belt and pulley system. The brushes are flooded with recirculated water, filtered through a Harrington Series A-B filtration system using a 20 micron cartridge to remove polish sediment, while the lap is sprayed through two Loc-Line fan spray plastic nozzles. Moistening the brushes facilitates the removal of the unwanted aluminum oxide polish. The brush completely encompasses the convex side of the lap whereas the bottom side of the lap is not brushed. To remove the unwanted polish from the bottom of the lap, it is instead subjected to a forceful steady stream of water provided by two Loc-Line round plastic nozzles.
Once the tray passes from the washing to the drying chamber (through a further slatted plastic apron curtain), it is immediately exposed to a thrust of shop air provided by five Exair® Air Jet units each of which delivers 12.5 oz. of force at a rate of 13.1 SCFM. There are three air units located at the top of the chamber and two below. One top unit is used exclusively to keep the top of the conveyor belt and rack dry. The other two units dry the tops of the laps only. An Omron® snap action switch engages the lap drying portion of the air system which is regulated in its deployment via an Omron® time delay relay. There is a ten second delay between the time the tray is loaded into the washing unit and the activation of the air system.
Before the tray exits the unit, it passes over four Exair® adjustable air nozzles which are located beneath the tray to blow excessive water from the washing chamber off of the lap. Each of these air units delivers 12.5 oz. of force at a rate of 13 SCFM. The latter are wired to the same delay system as the other air jets. Optionally a time delay relay may be installed to offset the amount of air used. The above described process takes approximately 28 seconds.
a are plan and elevational views respectively showing components of the belt/pulley drive system.
Referring now to the drawings wherein like numerals designate like and corresponding parts throughout the several views (except for
Water filtration unit 28 is supported by metal shelf 17. Electrical connections and supply are contained within NEMA box 27. National Electrical Manufacturers Association. Water resistant electrical component enclosure approved by NEMA for use in wet environments. Belt drive assembly 29 connects to nylon brushes 21, 21′. Brushes 21, and 21′ are housed in washing chamber 20 which is defined by flexible scree curtains 24 and 25. Water jets 22 supply filtered water to the brushes and to the top of trays 500 as they pass through. Lower water jets 22a force water upwards below trays 500. The water strikes the bottom of laps 507 by passing through apertures 508 (FIG. 5). The tops of laps 507 are completely encompassed by nylon brushes 21, 21′, and kept in place thereby. Unclean water is recovered from cabinet 11 by draining into tray 12 through holes 13a (
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| Number | Name | Date | Kind |
|---|---|---|---|
| 3530526 | Schmidt | Sep 1970 | A |
| 4589926 | Holmstrand | May 1986 | A |
| 4926520 | Watson | May 1990 | A |
| Number | Date | Country | |
|---|---|---|---|
| 20030217429 A1 | Nov 2003 | US |
