US1347766A - Lens-grinder - Google Patents

Description

D. TILLYER AND L. W. BUGBEE.

LENS GRINDER.

APPLICATION FILED NOV. 30, 1917.

ggy 'yfig Patented July 27, 1920.

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I r ,4 TTORNEYS E. D TILLYER AND L. W. BUGBEE.

LENS GRINDER.

APPLICATION FILED NOV. 30. 1917.

Patented July-27, 1920.

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2 SHEETS nw IVTOI? L w BUGBEE E .D 'r LLYER er 2a ATTORNEYS UNITED STATES,

PATENT OFFICE.

EDGAR D. TILLYER AND LUCIAN W. BUGBEE, SOUTHTBRIDGE, MASSACHUSETTS,

ASSIGNORS T0 AMERICAN OPTICAL COMPANY, OF SOUTHBIR-IDGE, MASSACHU- SETTS, A VGLUNTARY ASSOCIATION OF MASSACHUSETTS. I

LENS-GRINDER.

Specification of Letters Patent.

Application filed November 80, 1917. Serial No. 204,666.

To all whom it may concern:

Be it known that we, EDGAR D. TILLYER and LUCIAN W. BUGBEE, citizens of the United States,residing at Southbridge, in the county of Worcester and State of Massachusetts, having invented certain new and useful Improvements in Lens-Grinders, of which the following is a specification. This invention relates to improvements in grinding machinery and has particular reference to a novel and improved construction of machine for use in the grinding or constructing of ophthalmic lenses.

One of the leading objects of the present invention is the provision of apparatus which may be employed to simultaneously generate, form or produce a series of lenses, all having the same curve, and which will serve to con rol said curve and prevent wearing of the tool from the desired curve.

A further object of the present invention is the provision of a machine particularly adapted for use in the simultaneous formation of the two surfaces of a one-piece bifocal lens, which machine shall be so formed and constructed that a number of lenses may be ground or polished on it at one time, and in which the curves of both the reading and distance portion of the tools will be auto-' matically trued, or corrected during the grinding operation.

()ther objects and advantages of our improved construction should be readily apparent by reference to the following specification taken in connection with the accompanying drawings, and it will be understood that we may make any modifications in the specific details of construction shown and described within the scope of the appended claim without departing from, or-exceeding the spirit of our invention.

Figure I represents a vertical sectional view of one embodiment of our complete machine.

Fig. II represents a horizontal sectional view with the upper portion of the machine removed.

Fig. III represents a semi-diagrammatic view illustrating the driving of the several spindles.

Fig. IV represents a fragmentary semidiagrammatic plan View illustrating a different arrangement of our truing devices.

F 1g. V represents an enlarged sectional view through one of the lens blocks and intimately associated parts.

Fig. VI represents a modified form of truin wheel.

ig. VII represents a detail view of the resilient bearing.

Inthe drawings, the numeral 1 designates as an entirety the frame-0f our improved machine, formed with the bearings 2 for the main drive shaft 3, which is connected as by the belt 4 and pulleys 5 and 6 with the drive shaft 7 of the horizontally rotating table 8. This table 8 is preferably mounted on suitable ball or roller bearings 9 supported by the plate 10 and has formed thereon the annular grinding tool or lap 11, preferably formed with a central groove 12 of one curve and a pair of similar curved portions 13 disposed on each side of the central groove 12, the two portions '13 together being part of a circle in transverse section, asshould be clearly understood by reference to Fig. V.

J ournaled in'the bearings 14 at the upper portion of the frame is a second driven shaft 15 connected by the pulley 16 and belt 17 with the main drive shaft, and itself being provided with the driving gear 18 meshing with the pinions 19 on the lens driving spindles ,20, which have been illustrated as six in number, disposed about the shaft 15 as a center, and with their centers directly over the center of the groove 12 in the annular la 11.

t willv thus be seen that driving of the shaft 7 will rotate the table 8 and annular lap carried thereby, while at the same time the driving of the shaft 15 through the gear 18 and pinions19 will serve to rotate or spin the lens spindles 20 over the lap.

The spindles 20 are provided on their lower ends with the balls 21 adapted to fit in suitable recesses in the end of the lens blocks 22, and are provided with the arms 23 adapted to loosely fit within the sockets 24 of the blocks so that the blocks are held for slight rocking movement to accurately fit against the lap and at the same time have a driving connection with the spindles so that the Patented July 2'7, 1920.

blocks and thus the lenses 25 carried thereby are spun around over the groove of the lap. It will thus be seen that an extremely desirable grinding movement is provided, in that the table with its annular lap is rotating in one direction and at one speed, while the lenses are spinning against the groove "in the lap at a different speed and there is thus an absolute break-up of movement between the parts and very satisfactory grinding 1s accomplished. To permit of ready observation of the grinding and removal of any particular block and lens, as desired, without disturbing the other parts, we preferably secure on each'of the spindles 20a shift collar, as 26', adapted to be engaged by the shift lever 27 intermediately pivoted to the frame 1 in such position that depression of the handle portion of the shift. lever 27 will cause the operatingportion to engage the collar and raise the spindle until the pinion 18 is out of mesh with the gear 19, slight further movement of the handle swinging the lever past center to lock the spindle in raised position until the handle is again shifted. It will thus be seen that on account of this lifting movement the block may be readily disenga ed from the lower end of the spindle. If desired a suitable latch or locking device 28 may be provided on the block to interlock with the groove 29 on the lower end of the spindle'so that the block itself will be raised with the spindle and may be left there without attention indefinitely if desired, in place of it being necessary to grasp the block to prevent it being carried around with the table, as might otherwise be necessary.

The only difliculty to be experienced in connection with a grinding machine of the character just described is due to the fact that in time the transverse curve or curves of the annular lap may wear off true, so that the lenses will not possess exactly true spherical curves of desired dioptric value.

It is, therefore, one of the main objects of the present invention to provide means for automatically truing up or keeping these curves in shape, and in the accomplishment of this result we have shown at the right in Fig. I, supported in suitable bearings 30, the shaft 31 driven as by the belt 32 from the main drive shaft 3, and bearing thereon the central section of a sphere 33, the curve of the face of the sphere being the same as the transverse curve against which it fits. It will, of course, be, understoodthat when it is desired to use our machine for plain spherical grinding, the groove portion 13 will extend from one side to the other of the lap, and that in this event the face of the truing member 33 will fit the entire transverse curve of the groove at the point of contact, but in the present instance we have shown our machine as used for bifocal grinding, in which event there is preferably a truer provided for the central groove 12 and a second truer for the main'groove 13, although if preferred a truer such as shown in Fig. VI could be substituted for the member 33 of Fig. I, doing away with the sup" The essential advantage plemental truer. 4 of the form shown in Fig. I, however, re-

sides in the fact that by using the two separate truing devices each may be a section of a sphere of the-desired curve, and in this way the life and efficiency of the truing device will be much greater than would be the life of the truing device of Fig. VI, which would wear away and require replacement much quicker.

. In Fig. II, we have illustrated our truing devices with their axes of rotation extending transversely of theportion of the annular lap which they engage, but in Fig. IV we have shown them as extending parallel with the portion of the lap they engage, the general operation in either case being the same,

but slightly better results being obtained" be supported in floating bearings whose position is controlled as by the springs 36, to insure a light even engagement between the parts atall times.

From the foregoing description taken in 7 connection with the accompanying drawings, the construction and advantages of our 1 lens grinding machine should be readily apparent, and 1t will be seen that we have provided a novel and improved machine to 'produce a number of spherical or bifbcal lenses at a .single operation, in which any of' the spindles may be readily shifted into inoperative position as desired without affecting the operation of the remaining spindles, and in which the curve of the tool is kept at all times constant irrespective of the tendency of the lenses to wear same 'ofi' true, and consequently that we have provided a machine in which extremely high grade lenses may be economically and satisfactorily produced.

We claim:

A lens grinding machine, including 'a.

frame, a rotating table bearing an annular grinding tool, said tool having a main.

spherical transverse curve and a supplemental transverse portion of different curve, a main drive gear carried by the frame, a plurality of spindles having pinions at their upper ends to mesh with the drive gear, and In testimony whereof We have affixed our a plurality of lenses at their lower ends for signatures, in presence of two witnesses. engagement with the tool, whereby a pair of EDGAR D TILLYER surfaces of different foci will be formed on LUCIAN BUCBEE' each of the lenses, and means for independ- I ently shifting the spindles to move their Witnesses:

pinions out of mesh with the main drive HARRY H. STYLL,

gear. v H. K. PARSONS.

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