US2092727A - Grinding machine - Google Patents

Description

Sept. 7, 1937.

R. A. com;

GRINDING MACHINE Filed Nov. 25, 1935 2 Sheets-Sheet 2 F/GJG 3mm RHYME/Nu Fl. Ems

Patented" Sept. 7, 1937 UNITED STATES PATENT OFFICE 2,092,127 GRINDING MACHINE Raymond A. Cole, Norton Oompan Worcester, Mass, assignor to Worcester, Mass, at corpo The invention relates to grinding machines and with regard to its more specific features to a sizing mechanism therefor.

One object of the invention is to provide a sensitive work sizing apparatus adapted to setin operation instrumentalities for changing the grinding cycle automatically. Another object of the invention is to provide a sizing apparatus having no contact with'the work piece. Another object of the invention is to provide a sizing apparatus which may be readily installed on an existing grinding machine. Another object 'of the invention is to provide an eiiicient sizing apparatus particularly adapted to function to con trol the. size of cylindrical objects and including a light sensitive device. Another object of the invention is to provide a work sizing mechanism particularly applicable to use in connection with external grinding of a shaft or the like where relative reciprocatory traverse between work piece and grinding wheel is employed. Other objects will be in part obvious or in part pointed out hereinafter. The invention accordingly consists in the features of construction, combinations of elements, arrangements of parts, and in the several steps and relation and order of each of said steps to one or more of the others thereof, all as, will be illustratively described herein, and the scope of the application of which will following claims.

In the accompanying drawings, in which is shown one of various possible embodiments of the mechanical features of this invention,

Fig. 1 is a vertical transverse sectional view showing part of the base and the work table of a grinding machine, and illustrating also the cali-' pering mechanism, 1

Fig. 2 is a plan view of the support for the light source and lenses,

Fig. 3 is a vertical sectional view taken on the line 3-4 of Fig. 2,

Fig. 4 is an electric diagram,

Fig. 5 is an opticaldiagram,

Figs. 6 and 'l are plan views of certain lenses, 2

respectively. I h v V I provide a grinding machine including a ma- .chine base Ill having usual ways H, l2 for the support of a work carriage I3 which supports a work table I 4 upon which issupported a headstock anda tailstock, not shown, for the support, and rotation of a work piece I 5 which is to be ex-, teriorly ground. Grinding may be by the socalled plunge-cu method, in which the grindlng wheel advances relative to the work piece beindicated in the without relative traverse thereof, but by reason of the fact that there is no contact between the sizing device and the workpiece, and it is located opposite the grinding wheel, the invention is particularly applicable to grinding which includes the relative traverse between wheel and work piece. Accordingly, the usual mechanism, or any desired form thereof, for traversing the work piece by a longitudinal reciprocation of the carriage l3 may be provided. Such mechanism has not been illustrated herein as many forms thereof are well known.

I provide any desired type of cross slide and feeding mechanism therefor, anda wheel head for supporting a grinding wheel it, together with a drive for rotatingthe grinding wheel. As cross slides and wheel rotating mechanisms are themselves well-known, I have not illustrated any specific embodiment thereof herein. Specifically the sizing mechanism of .the present invention may be connected to operate the cross feeding apparatus disclosed in my copending application Serial No. 44,204 filed October 9, 1935. As will be hereinafter described, when the work piece comes to the desired size a circuit is closed which may be a power circuit, such as allO-volt circuit,

and this may operate a solenoid, disposed whereever desired, and I wish-it understood that any prior type of grinding machine having any desired controlling instrumentalities may be operated by the sizing apparatus of the present invention, by operating the desired control with the solenoid so energized, and I have above made reference to a specific embodiment of a grinding machine with solenoid control.

Considering now the sizing apparatus, and referring to Fig, 1, I provide a source of light represented by a lamp 118, and I provide a photoelectric cell tube l9v in a casing 20 and when suflicient light from the lamp I8 reaches the cathode 2| .(Fig. 4) of. the photoelectric cell, the circuits are provide a special lamp with a point source of light such as is known as a point-of-light lamp. The

light source in such a lamp is a luminous ball 22,

. the conductorswhlch convey the electricity to this .ball 22 being non-radiating. As the" ball 22 has some dimensions, the light is not a'point in the fullest sense, but as the ball 22 is very small the source is fairly close to a point, and the invention maybe carried out in actual practice using such a lamp.- Still referring to Fig. 5, in front of the lamp I8 is a color filter 23 which cuts the spectrum of the light source to a narrow band so that diffusion of light by refraction ofthe difierent wave lengths at different angles will be avoided to a sufficient extent.

In front of the color filter 23 are a pair of condensing lenses 24 and 25 which condense'the light into a cylindrical beam. For convenience I have selected three rays to illustrate the optics of the system, these rays being identified by the letters a, b and 0, wherein a is the central horizontal ray, b is the top ray and c is the bottom ray.

Still considering Fig. 5, the three rays 11, b and c are parallel after leaving the condensing lens 25. They now pass through a lens 26 which is convex .as seen from the side, but rectangular in shape as seen from above or in plan view (see I Fig. 6). Thus the rays b and c are caused to approach each other, but other rays in the same horizontal plane as the ray a do not approach ,each other. That is to say the beam is caused to converge in one plane but not in a plane normal thereto. The lenses 24 and 25' are condensing lenses whose surfaces are generated from curved lines. Lens 26 is a condensing lens whose surfaces are generated from straight lines.

The lens 26 is located close to the work piece l5, and the rays a, b and 0, together with all the other rays forming the light beam, are reflected from the surface of the work piece l5. be noted that the axis a of the beam is below the center of the work piece, and in fact all the rays strike the work piece below the center thereof. Speaking generally, therefore, the rays will be reflected downwardly. In Fig. 5' the rays a, b and c are represented in full lines upon reflection from the work piece IS in that position which they occupy when the work piece l5 has reached the desired size. It will be seen that rays a1, b and c are still parallel to each other. The beam of light is now flattened, so that as viewed from the side as in Fig. 5, its greatest width is represented by the distance between 'b and 0 below the work piece l5. As viewed from the front, however, its

greatest width is the same as the distance between b and 0 between the lenses 25 and 26. The rays a, b and 0 together with all the other rays of the beam, which are still parallel to each other. Strike a mirror 21 which is preferably at 45 to the horizontal, the beam striking the mirror 21 in a vertical direction. As a result, the entire beam is reflected horizontally. The beam strikes another mirror 28 which is also preferably at-45 to the horizontal, the two mirrors 2'| and 28 forming a V, as shown in Fig. 5. The beam now is reflected vertically upward, and strikes a third mirror 29, whereupon it progresses horizontally. Its cross section is still the same as it was ever since it left the work piece l5, andall the rays thereof are parallel to each other, except that slight variations are introduced by reason of the fact that a perfect point source of light has not yet been achieved. A certain amount of diffusion will occur on account of this fact but is not sufficient to prevent the operation of the apparatus in actual practice. The beam a, b. c and the other rays following reflection from the work piece l5 may be correctly characterized as having a focal length of infinity. As will hereinafter be graphically explained, this condition exists only when the work piece is at a particular size, and this provides a means and method of determining when the work piece is at a desired size.

The light beam including the rays m, b and 0 now passes through a lens 36 which is shown in I plan view in Fig. 7. This lens 36 contracts the beam in a horizontal plane but does not affect it in a vertical plane. The result at the photo- It will deal larger than the finished work piece I5 than would ordinarily occur in actual practice. Rays 0/, b and c are shown reflected from the oversized work piece l5a. It will be seen that the ray a. hit the wrong mirror, viz. the mirror 28, and moving back to the mirror 21 did not even strike the mirror 29 and its ultimate path as indicated in Fig. 5 is completely remote from the photoelectric cell. The ray b has a path which reintersects the lens 26. It would not be emerging from the lens 26 as shown; it would be partially reflected and partially refracted but with no chance of coming anywhere near the cathode 2|. The ray 0' is shown as striking both mirrors 21 and 28 but ending way below the lens 30. As the ray 0 is a marginal ray, it may be said that no light will reach the cathode 2| from the light source 22.

This optical apparatus is so sensitive that, with a work piece difference of only .001", a great difference in the beam as it passes the mirror 29 is produced.

It will be seen that there are two effects from the optical arrangement shown and described.

In the first place there is whatI term the leverage effect, whereby as the work piece changes in size the central axial ray a moves angularly. By giving the beama a comparatively long distance to travel, this leverage effect results in a comparatively great displacement of the beam at the receiving end. There is also what I term the focusing effect. Only when the work piece is at a given size will the bulk of the rays be in parallelism after they leave it. Accordingly, with the light source 22 at a given position, with the cathode 2| at a given position, and with given lenses and mirrors all located in given positions, the light will pass as described only if the work piece is of a given size. The apparatus may be set up by placing in the machine a work piece of the desired size to which it is intended to grind other work pieces, then adjusting the lenses relative to each other and relative to the work piece, and adjusting the light source up and down until the desired beam which will energize the circuits is produced. It is desirable to change the adjustments until Just enough light reaches the photoelectric cell cathode 2| to operate the electric circuits.

Considering now the physical structure and the mountings for the various lenses whereby the invention may be carried out in actual practice, and referring to Figs. 1, 2 and 3, the lamp I8 is enclosed in a lamp box 3| having a circular opening 33 facing the lens 24. Lamp I8 and box 3| are mounted upon a slide 34 which is mounted wheel-42 the pinion 39 can be operated, and therefore the slide 34 moved in a horizontal direction.

The support 36 has a portion 42 extending to the front of the machine which merges with the downwardly extending vertical slide 43. A support 44 has a rectangular groove 45 receiving a rack 46 attached to the slide 43, and a pinion gear 41 meshes with a rack 46, the pinion gear being mounted on the end of a shaft 48 which is journaled in the support 44, and by means of a hand wheel 50, the slide 43 may be moved up and down. The support 44 extends downwardly and is attached to the machine base III, as shown in Fig. 1. Thus the slide 34 may be moved in a horizontal direction by turning the hand wheel 42, and it may be moved in a vertical direction by turning the hand wheel 58.

The lenses 24, 25 and 26 may be adjustably mounted on the slide 34 in any suitable manner. As shown, a post 5| supports a tube 52 in which are secured the lenses 25 and 26, while a tube 53 which is telescopically mounted upon the tube 52 supports the lens 24.

Considering now one electric circuit which may respond to light impinging upon the cathode 2i, and referring to Fig. 4, a 110-volt A. C. line 55 has connected to it conductors 56 and 51 leading to terminals 58 and 59 of a. transformer primary 60. Three secondary coils 6|, 62 and 63 are energized by the primary coil 60. A non-inductive potentiometer resistance 64 is connected across conductors 65 and 66 of the coil 6|. Conductor 65 leads to the anode 61 of the photoelectric cell l9. Conductor 66 leads to condenser 68 which is connected by conductor 69 to conductor '10 which connects to cathode 2| of the photoelectric cell l9.

The secondary coil 62 energizes filament 13 of an amplifying or triode tube 14. A grid 15 of the tube 14 is connected by a conductor 16 to a noninductive resistor Tl the other end of which is connected to the conductor 10. A plate 80 in the tube 14 is connected to a conductor 8| which is connected to a terminal 82. The secondary 63 has one end thereof connected to a terminal 83. Connected in parallel by the terminals 82 and 83 are a condenser 84 and a sensitive relay coil 85. The other end of the secondary coil 63 is connected to a conductor 86 which connects to the movable element 81 of potentiometer 64. Conductor 86 is also connected by a lead 88 to the midpoint of coil 62. It will now be seen that a certain degree of illumination of the photoelectric cell cathode 2| causes energization of relay coil 85 and the apparatus is adjustable by means of the potentiometer 6481.

In so much as the energization of the relay 85 may be momentary I have further provided a relay to close and keep closed the final circuits upon any energization whatsoever of the sensitive relay. As shown in Fig. 4, conductor 56 also connects to a terminal 90. Conductor 51 connects to a relay coil 9| and the other end of the relay coil 9! is connected to a terminal 92. A pendulum contactor 93 is adapted to connect terminals 90 and 92 and this contactor is arranged to be operated by a long arm 94 of an armature 95 actuated by the coil 85. Therefore, energization of the relay coil 9| even momentarily closes a double knife switch 91 electromagnetically operated by the coil 9|. One set of the terminals of the knife switch 91 is connected by shunt leads 98 and 99 to the power lines 56 and 51 tively, while the other terminals of the respecdouble knife switch 9'! connect to power lines I and IM which lead to an operating solenoid.

Pendulum contactor 93 may be of spring steel so that normally it will lie in the position shown in Fig. 4 but a slight force will throw it into contacting position. The photoelectric cell cathode 2| is preferably a sensitive cathode and a certain definite amount of light on it will cause enough current to flow in the relay coil to close the circuit by means of the contactor 93.

The solenoid energized by the lines I and llll when the knife switch 91. is closed may operate to withdraw the grinding wheel I 6 or otherwise alter the grinding cycle, either as disclosed in my aforesaid copending application or in any other manner. It will thus be seen that there has been provided by this invention a method of sizing and an apparatus in which the various objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As various possible embodiments might be made of the mechanical features of the above invention and as the art herein described might be varied in various parts, all without departing from the scope of the invention, it is to be understood that all matter hereinbefore set forth, or shown in the accompanying drawings, is to be interpreted as illustrative and not in a limiting sense.

I claim:--

. 1. Method of determining the size of work pieces circular in cross section which are being reduced in diameter which comprises producing a beam of light, directing the beam of light upon the work piece at such an angle that as the work piece varies in size the axis of the reflected beam moves angularly', and providing a light sensitive device at a particular point in the locus of the reflected beam as it moves responsive to reduction-in diameter of the work piece.

2. Method of determining the size of work pieces having a circular contour which are being reduced in size which comprises producing a beam of light, directing the beam of light onto the work piece at such an angle that as the work piece varies in size the axis of the reflected beam moves angularly, and providing indicating means responsive to the beam of light at a particular angular position thereof which the light beam assumes when the work piece has been reduced to a particular size.

3. Method of sizing work pieces having a circular contour which comprises producing a beam of light, directing the beam of light onto the work piece, and placing an indicator at a position whereit will respond to a particular concentration or focusing effect of the reflected beam due to the specific size of the work piece.

4. Method of sizing work pieces having a circular contour which comprises providing a light source, causing concentration of the light toward a focus, reflecting the light by the work piece ahead of the focal point, and placing an indicator in the path of reflection where it will re-= spond to a particular concentration of the reflected light due to a specific work piece size.

5. Method of determining the size of work pieces having a cylindrical contour which comprises providing a light source, condensing the light, further condensing the light in one plane but not in a plane normal thereto, directing the light onto the work piece, providing a light sensitive element'in the locus of the path of the beam subsequent to its reflection from the work gization of the element when the beam impinges v said element.

6. In a grinding machine, a grinding wheel, a carriage, ways supporting said carriage-for reciprocation which produces a relative reciprocatory traverse between'the grinding wheel and a round work piece, a photoelectric cell, a solenoid to control the grinding action, electric circuits to energize said solenoid responsive to energization of the photoelectric cell, and light producing apparatus comprising a source of light, and a lens system which produces a beam of light the rays of which have a different angular relation in one plane from their angular relation in another plane and positioned to direct the beam onto the work piece, the photoelectric cell being located to receive the reflected beam only when the work piece has been ground to a certain given size.

'7. 'In a grinding machine, a grinding wheel, a

' carriage, ways supporting said carriage for reciprocation which produces a relative reciprocatory traverse between the grinding wheel and a cylindrical work piece, a photoelectric cell, a-solenoid to control-the grinding action, electric circuits to energizesaid solenoid responsive to energization of the photoelectric cell, and light producing apparatus directing light upon a work piece which upon reflection therefrom at a particular size of the work piece will have a focal length of infinity, and positioned to direct the reflected light to the photoelectric cell when the focal length is infinity.

8. Method of sizing work pieces cylindrical in contour which involves producing a beam of light having a short focal length in one axial plane and a focal length of infinity in a plane perpendicular thereto, the short focal length being such that at the critical or desired size of the cylindrical workpiece the reflected beam has a focal length in the first mentioned plane which is infinity, and placing a work piece in the path of such beam and placing a light sensitive device in the reflected path of the beam so that the beam will concentrate upon the light sensitive device when it has a focal length in the first mentioned plane which is infinity.

9. In apparatus for sizing a work piece having a surface of revolution, a source of light, a system of lenses in front of said source of light causing the light to converge in a plane perpendicular to the work piece axis and to focus in a plane normal to said first plane differentially and to impinge upon said surface of the work piece to be reflected therefrom, a light sensitive device so located that only at a given size of work piece will the reflected beam actuate it, electric circuits including said light sensitive device, and an instrumentality actuated by said electric circuits to indicate such size.

RAYMOND A. COLE.

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