US2141308A - Lens surfacing machine - Google Patents

Description

Patented Dec. 27, 1938 UNITED STATES PATENT OFFICE LENS SURFACING MACHINE Joseph J. McCabe, Rochester, N. Y.,

Bausch & Lomb Optical Company,

assignor to Rochester,

3 Claims.

The present invention relates to lens surfacing machines and more particularly to pressure spindies therefor.

The hand lens surfacing machine as used in 5 the art, has a rigid pressure spindle, and, un-

less the position of the work on the lap and the position of the hand lever and spindle are accurately adjusted, the machine is very noisy and objectionable. The position of quiet opera- .0 tion is difficult to find and so, in shops where quiet is essential, a large amount of time is consumed in adjusting the machine before any work can be done.

One of the objects of the present invention is to provide a lens surfacing machine which is efficient and silent in operation. Another object is to provide a pressure spindle which will insure quiet operation of a lens surfacing machine.

These and other objects and advantages reside in certain novel features of construction, arrangement and combination of parts as will hereinafter be more fully set forth and pointed 1 out in the appended claims.

Referring to the drawing:

Fig. 1 is a side elevation with parts in section, showing an embodiment of my invention.

Fig. 2 is an elevation of the spindle.

Fig. 3 is an elevation of the spindle at right angles to that in Fig. 2.

Fig. 4 is an enlarged plan view showing the preferred position of the spindle in relation to the work and lap.

In the embodiment shown in Fig. 1, I designates a splash pan having a central opening II through which extends a rotatable shaft I2 carrying the usual lap I3. The shaft I2 may be rotated from any suitable source of power, not shown, as is well known to those skilled in the art. An upright bracket I4 is fixedly mounted on a support, not shown, and has a pressure lever I5 pivotally secured thereto. This lever I5 carries a clamp IS in which the pressure spindle I1 is adjustably and removably fixed. The structure thus far described is conventional and is shown only diagrammatically. A fuller description of a suitable surfacing machine can be found in U. S. Patent No. 1,381,245 issued June 14, 1921 to Leon G. Simpson.

The spindle H is rigidly secured to the upper side of one end of a block I8 which is provided with a slot or groove I9. A work engaging point or pin 20 is secured to the lower side of the same end of the block 18 and presses against the work piece 2|. The slot or groove I9 in the block I8 causes the block I8 to function as a U-shaped leaf spring and form a resilient connection between the spindle I1 and point 20.

The spindle Il may be positioned so that the slot IS in the block I8 faces in any direction except in that opposite the direction of rotation of the lap. Preferably the slot I9 faces in the direction of rotation of the lap as shown in Fig. i, and in this position the noise and chatter of the conventional surfacing machine is almost entirely eliminated. Apparently, the noise and chatter of the prior art machine was due to the fact that the work piece vibrated and this vibration was conducted through the rigid spindle to other parts of the machine. In the present invention the resilient connection due to the block I8 absorbs this vibration. It is also believed that the vibration itself is materially reduced if not entirely eliminated. The resilient block I8 permits the work to move away from the lap when a hard or high spot on the lap engages the work and therefore the cause of vibration is avoided.

From the foregoing it will be apparent that I am able to attain the objects of my invention and provide a lens surfacing machine which is efiicient and silent in operation. The resilient connection shown in the drawing is the preferred form and presents certain manufacturing advantages, but other resilient connections can obviously be used. Various other modifications can also be made without departing from the spirit of my invention or the scope of the appended claims.

I claim:

1. A pressure spindle for a lens surfacing machine comprising a work engaging point, a shaft, a block formed of resilient material, and means for rigidly securing said point and said shaft in axial alignment to one end of said block, said block being formed with a slot perpendicular to said point and shaft and extending from said one end toward said other end.

2. A lens grinding machine comprising a grinding lap, means for rotating the grinding lap, a work holder adapted to be held eccentrically against the grinding lap, a spindle, a resilient U- shaped leaf spring secured by one arm to said spindle, a point secured to the other arm of said spring in substantial alignment with said spindle for engaging said work holder, said spring being mounted with its open end facing in the direction of rotation of said lap, and means for applying pressure to said spindle.

3. A lens surfacing machine comprising a grinding lap, means for'rotating thegrinding lap, a Work holder adapted to be held eccentrically against said lap and means for applying pressure to said Work holder, said means comprising a pressure arm extending over said lap, a spindle secured to said arm and projecting down- Wardly therefrom toward said lap, a member secured to the lower end of said spindle having a free resilient portion extending substantially perpendicular to the spindle in the direction of rotation of said'lap, and a point secured to said resilient portion and extending downwardly substantially perpendicular to said portion to engage the Work holder.

JOSEPH J. McCABE.

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