US1588435A - Lens-grinding apparatus - Google Patents

Description

C. A. ADAMS LENS GRINDING APPARATUS Filed Dec. :51 2 Sheets-Sheet 1 mm a. j 2mm )7, M ATTORNEY.

June 15 1926.

c. A. ADAMS LENS GRINDING APPARATUS Filed Dec. $1, 192:5 zsnuu-suut z INVENTOR.

M ATTORNEY.

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Patented June i 15, 1926.

UNITED STATES PATENT OFFICE.

LENS-GRINDING APPARATUS.

Application filed December 31, 1923. Serial No. 688,694.

My invention pertains to lens grinding apparatus, and has for its chief purpose to simplify the operation of .producing o tical lenses, and increase the output thereofi One of the objects of the invention is to form a blocker of increased capacity, togetherwith a special form ofmachine with which the same may be used.

Another object thereof is to produce a blocker of a hollow formation, from which the air may be exhausted, and provided on its outer surface with spots to receive the lenses, which spots are in communication with the interior of the blocker, so that the lenses can be caused to adhere thereto by the vacuum in the interior of the blocker.

The above named, and other features and advantages of the invention, will more full appear from the following specificatlon, re 1 erence being had to the accompanying drawings, in which: 1

Fig. 1 is a side elevation of a machine forming a part of the invention.

Fig. 2 is a vertical section thereof, with a blocker in place therein.

Fig. 3 is a plan view thereof. Fig. 4 is a view similar to Fig; 1, showing a modified use of the machine.

Fig. 5 is a side elevation of a modified form of blocker.

Fig. 6 is a view of a spherical blocker of a similar formation as the one shown in Fig. 5.

Fig. 7 is a section.

Fig. 8 is a similar view of the vent 47.

Referring first to the first three figures of the drawings, the reference number 1 indicates a pairof uprights, to the-sides of which detail of the air-valve 45, in

is attached a pair of brackets 2 and 3, the

first of which is mounted at a distance above the other. Supported by the bracket 2 are twin bearings 4 and 5, spaced apart to provide room for a worm-gear wheel 6, in mesh with a worm 7 on a shaft 8, rotatably mountedin a pair of arms 9 secured to the bracket 2. The shaft 8 and worm thereon are accommodated in an opening 10 in the bracket, and power may be applied to said shaft to impart rotation to the worm 7 and gear wheel 6. Under some manufacturing conditions the shaft 8 would comprise a line shaft, with a number of the machines connected therewith. The gear-wheel 6 is held in position by means of a vertical shaft 11, rotatable with the wheel, but vertically formed in its surface, adapted to movable with relation thereto by means of a rib and channel formation shown at 12.

On the lower end of the shaft 11 is a disk 13, to which is attached a bowl-shaped member 14, commonly called a tool, by means of a set-screw 15. In the rotary movement of the shaft 11 the tool 14 is caused to revolve therewith.

The bracket 3 supports a pair'of bearings 16 and 17, spaced apart to provide roomfor a worm-gear wheel 18, in mesh with a worm drive 19, fixed on a shaft 20, journaled in the ends of arms 21, attached to the bracket 3.} A space 22 is provided in said bracket for the shaft and worm drive thereon, and said shaft also is designed to have power apphedthereto, to'cause a rotation thereof in a direction opposite to the rotation of the shaft. 8. The wheel 18 is fixed to a vertical shaft 23, rotatable in the bearings 16 and17, and at the upper end of the shaft 23 is a disk 24, to which is fixed a tool 25, by means of asst-screw 26. The tools 14 and 25 are hollowed .out, forming semi-spherical res cesses 27 and 27, the edges of which are flared outwardly at the rims of the'tools.

' In Fig. 2 the machine is shown with a spherical blocker. 28 contained in the tools 14 and 25, said blocker having spots 29 "'01 lenses, as shown at 30. These spots are formed in the manner set forth in a companion application filed in theUnited States Patent Oflice by applicant 'onthe 26th dayof De-v cember, 1923, Serial No. 682,693, and as set forth therein, the lenses are heldin position in the spots'by a thin layer of pitch or similar adhesive. The diameter of the blocker corresponds with that of the recesses in the tools 14 and 25, and when the lenses are perfectly ground the outer faces thereof conform to the curvature of the blocker, so that the blockerand lenses thereon will conform to the inner shapes of the recesses 27 and 27. The lower tool is provided with a quantity of abrasive material in the usual manner, and-by reason of the tools 14 and 25 being rotated in opposite directions the position of the blocker'28 is constantly chan ing therein, so that all of the lenses are su mitted to the grinding operation. As the work proceeds the tool 14 is moved gradually downwardl by force of gravity, until the blocker is fina 1y contained within the recesses in the tools, with its face in contact with the walls thereof. When I the lenses positioned thereon, it is in contact tion.

with the flaring faces of said recesses, as shownin Fig. 2.

A special advantage is gained by the use of the spherical blocker, which has been impossible heretofore on account of the manner of preparing the blocker for operation, which consisted in providing its surface with a layer of pitch, with spots formedthereon. With this method it was only ossible to make use of a semi-spherical bloc er, with a limited number of spots thereon, a portion of the blocker near the edge thereof being blank, for waste space. By the use of the spherical blocker it is not only possible to double the number of spots which are found on a semi-spherical blocker, but an additional row of spots can be provided along the line of the greatest diameter of the sphere. This increases the capacity of the blocker by approximately fifty per cent. The grinding operation is also speeded up to a considerable'extent by the use of the two tools 14 and 25, operating in opposite directions.

The shaft 11 is shown provided with a central channel 11, which is continued downwardly through the tool 14, through which water may be introduced to the center of the tools during the grinding operation, to keep the abrasive material in a desired moist condition, and to prevent the parts from becoming overheated from the friction-resulting from the grinding opera- In Fig. 4 the tool'14 is replaced by a crank member 31, carrying a pin 32, eccentrically positioned, for engagement with the shank 33 of a blocker 34. This blocker is of the shape of those now in use, but is ofa hollow formation, the flat side thereof being closed by a plate 35. In the curved surface of the blocker are spots 36. out therein in the manner hereinbefore set forth, and provided with central openings 37, communicating with the space within the blocker. By providing the spots'with a plurality of lenses, and exhausting the'air fromjthe block, the suction on the inner faces of the lenses will cause them to adhere tightly to the spots,

enabling them to pass through the grinding operation. Air may be exhausted from the blocker through a tube 38, containing a check-valve, (not shown) which prevents the I water, to cause them to adhere slightly until the air is exhausted from the blocker. This may be done by an air pump or simi lar machine. The blocker is then placed in .the tool 25 and rotated in the usual manner. After the lenses have been sufliciently ground and polished, they can be released from the blocker by admitting air to the interior thereof through an opening in the plate 35 normally closed by a thumb-screw In Fig. 6 is shown a blocker 41 of spherical form, for use in the machine hereinbefore first described, but constructed after the manner of the blocker 34, the sphere being hollow, and having spots 42, with central openings 43 communicating with the interior. The lenses are positioned on the spots 36 the same as in the blocker 34, and the air exhausted from .theblocker. This can be done through an opening 44 in one side of the blocker, fitted with a tube 45, provided with a check-valve preventing return of air inwardly through the tube. The outer end of the tube projects into the opening 44,v for suitable connection with an airpump, and said projection is normally closed by a cap 46, which is within the curve of the blocker. After being provided with a plurality of lenses the blocker 41 is placed in the machine, in the same manner as with the blocker 30," and the lenses reduced to the desired convexity. The air suction can be released by means of an opening 47 in the shell of the blocker, fitted with a screw 48, seated on a gasket 49,- the head of the screw being below the surface of the blocker. Upon the air being returned to the blocker, the lenses can be removed therefrom. The spots 42 are provided with gaskets 50, to prevent the passage of air between the lenses and faces of the spots.

Upon occasion the shaft 11 can be held in an elevated position by means of a handscrew 51 in the bearing 4.

What I claim,and desire to secure by Letters Patent, is:

1. In a device -of the class described, a pair of lens g'ri'nding tools, mounted to operate in opposition, in opposite directions; and provided-with semi-spherical recesses; and a spherical blocker provided on its face with lens retaining spots. of a diameter corresponding with that of said recesses.

2. In a device of the class described, a spherical blocker having a plurality of lens spotting depressions formed on its surface. a 3. In a device of the class described, a. spherical blocker having a plurality of lens spotting depressions formed on its surface and means for seating and securing lens] blanks within such depressions. I 4. In a device of the class described. a" pair of lens grinding tools mounted to open ate in opposite directions and provided with semi-spherical depressions, and a s herical blocker provided on its face with ens retaining depressions.

5. A device of the character described comprising a pair of opposed lens grinding tools having recesses formed therein, a blocker adapted to have a plurality of lenses mounted thereon, said blocker adapted to be received in the recesses of the opposed tools, and means for rotating the tools in opposite directions, the rotation of the tools causing the blocker to be rotated within the recesses relative to the tools to bring the lenses carried thereby into engagement with different portions or surfaces of the tools.

6. A device of the characted described comprising apair of opposed lens grinding .tools having recesses formed therein, a

blocker having lens receiving spots formed around its surface, said blocker adapted to be received in the recesses of the opposed tools, means for securing'the lenses in the spots in the blocker, and means for rotating the tools in opposite directions, the rotation of the tools causing the blocker to be zotated within the recesses relative to the ,ools.

In testimony whereof I'aflix my signature,

CHARLES A. ADAMS.

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