US2349686A - Cutting apparatus - Google Patents

Description

May 23, 1944. D. v. WATERS CUTTING APPARATUS Filed June 1o, 1941 4 Sheets-Sheet l FIG. I

FIG. 3

nwe-Nro@ o. u WA 'rERs sRma-wawt A TTORNEY May 23, 1944. D. v. WATERS lCUTTING APPARATUS Filed June' 10, 1941 4 Sheets-Sheet 2 Nw m V. m0 D. a. w

' ATTORNEY May 23, 1944. f D. v. WATERS 2,349,686

CUTTING APPARATUS Filed June 10, 1941 4 Sheets-Sheet 3 FIG. ll

-f las 4' /2 2s 22 12a INVENTOR D. K WA TEPS A Tryon/ver May 23, 1944- D. v. WATERS 2,349,686

CUTTING APPARATUS Filed June 10, 1941 4 Sheets-Sheet 4` F G. 6 I

f/O l L/M/T SW/TCH /67 OPENS VALVE F, 6 l', /35 T0 START RETURN MOVEMENT 0F' TABLE Home /aa su fers T T 7' MO o@ ,0a s AR s ROCK/NG MOTION ROCK/NG MOT/ON F550 VALVE/a5 nosa-amro@ l sroPPEa r/ME new @sur las D. WA TEPS ATTORNEY TABLE STARTS FEED/NG MOVEMENT EY SPR/NG /44 LIM/T SWITCH /66' STA R TS MOTOR /08 RE VE IPSE TIME DELAY RELAY lSTARTS Patented May 23, 1944 UNITED naar STATES PATENT OFFICE CUTTING APPARATUS Application June 10, 1941, Serial No. 397,361

4 Claims.

This invention relates to cutting apparatus, and more particularly to an apparatus for cutting quartz crystal plates from a quartz crystal blank.

Quartz crystal plates are used, for example, in lters in the communication arts, and these plates are usually cut by the aid of a diamond edge saw from quartz crystal blanks. Due to the brittle nature, the granular structure and the natural hardness of quartz crystal blanks. the cutting of plates of definite and uniform thickness therefrom is quite difficult and painstaking. 'Ihe crystal plates cut from the crystal blanks must be cut with the grain of the blank and when the plates are rather thin difficulties arise in avoiding breaking the plates before the cut is completed.

An object of the invention is to provide a cutting apparatus which is particularly adapted for eficiently and accurately cutting plates from quartz crystal blanks.

With this and other objects in view, the invention comprises a cutting apparatus including a work or quartz crystal table for the support thereof which, in addition to being mounted for movement into various angular positions relative to a driven cutting element, is caused to move arcuately through a cutting operation by the element and simultaneously oscillated to cause substantially point contact between the element and the work, means also being provided to shift the support after each cutting cycle to position the work for a new cut'.

Other objects and advantages will be apparent from the following detailed description when taken in conjunction with the accompanying drawings, wherein Fig. 1 isa side elevational View of the apparatus;

Fig. 2 is a top plan view of the apparatus, portions thereof being broken away;

Fig. 3 is a fragmentary sectional View taken substantially along the line 3--3 of Fig. 2;

Fig. 4 is a side elevational view of the apparatus, portions thereof being removed to illustrate the table and oscillating mechanism in the forward position;

Fig. 5 is a side elevational view of the apparatus similar to Fig. 4, showing the table and its oscillating mechanism in its rearmost posiwork and the cutting element at one end of an oscillatory movement of the work;

Fig. 10 is a fragmentary detailed view illustrating the relative positions of the work and the cutting element at the other end of the oscillatory movement of the work;

Fig. 11 is a sectional ,view of the work illustrating a completed work;

Fig. 12 is a simple wiring diagram illustrating the electrical as well as the pneumatic control means for the mechanism moving the work supporting table;

Fig. 13 is a diagram illustrating an operating cycle of the apparatus and the points during which various portions of the structure function to automatically carry out the operation of the apparatus; and

Fig. 14 is a fragmentary sectional view taken along the line ill-i4 of Fig. 1.

Referring now to the drawings, attention is first directed to Figs. 1 and 2, which illustrate a hollow base lll mounted upon a suitable support, such as a table Il, and having spaced frames, indicated generally at l2 and I3, mounted thereon by any suitable means (not shown). The frames l2 and I3 are identical in structure excepting that one, the frame I2, might be called a right-hand frame while the other might be called a left-hand frame due to the fact that channel members of which the frames are composed have their open sides facing outwardly. In each frame there are vertical channel member l5 and I6 joined at their lower extremities by interposed channel members ll lying upon the upper surface of the base l t), while the upper eX- tremities of the channel members l5 and I6 of each frame are joined by a diagonally projecting channel member I8 as illustrated in Fig. 1. Shaft supporting brackets 2| of the contour illustrated in Figs. 1, 3, 4 and 5 project downwardly in the hollow upper portions of their respective vertical members I5 of each frame, where they are secured rigidly by any suitable means such as screws. Similar shaft supporting brackets 22 project downwardly in the hollow portions of their respective vertical frame members i6 and are similarly secured in place. A suitable shaft 23 extends through the brackets 2l and has nuts 2li threadedly disposed upon threaded ends thereof to secure the shaft against displacement. A similar shaft 25 has threaded ends extending through the brackets 22 and are secured in place by nuts 26 disposed on the said threaded ends.

A pair of pendulum levers 28 is mounted on the shaft 23 between the frames l2 and I3 and held in their respective spaced positions by a sleeve 353. In actual structure the pendulum levers 28 are mounted upon roller bearings 3l, only one of which is shown and this being illustrated in Fig. 3. The roller bearings are mounted upon the shaft 23 and held against lateral displacement on one side by washers 32 and on the other side by sleeves 33, the latter abutting against the bearing brackets 2|. As illustrated in Fig. 3 and also in Fig. 2, the ends of the sleeve 30 have flanges 34 apertured for screws 35 and 38 to secure the flanges to their respective pendulum lever 28, the screws 35 extending through apertures in the levers and threadedly secured to respective end plates 38, closing the ends of the lever and sleeve assemblies on the shaft 23.

Pendulum levers (58 are mounted upon their shafts 25 by the aid of bearings and with a structure identical with the mounting of the pendulum levers 28, upon their shaft 23 and, as illustrated in Fig. 3, including a roller bearing for each pendulum lever lill, a spacing sleeve (il (Fig. 2) with flanges 42 at the ends thereof to receive screws (not shown) to secure the flanges 42 to their respective pendulum levers 85 and also to the end plates 43, completing the mounting structure for the pendulum levers 88 identical with that of the pendulum levers 28.

Returning now to the pendulum levers 23, it will be observed that these levers are joined by an intermediate reenforcing member or plate L35. The lower ends of the levers 28 are bent forwardly, providing substantially horizontal portions 41, in the ends of which stub shafts t8 are mounted. The stub shafts i8 assist in supporting rocker arms 5|) short of the ends thereof, as illustrated in Fig. 2. These arms extend rearwardly from the stub shafts, are bent inwardly, that is toward each other, at like angles for short distances, as indicated at 5| (Fig. 2), and are then provided with apertured portions 53 lying in parallel planes at right angles to the shafts 23 and 25. The portions 53 of the rocker arms 58 are disposed on bearings similar to the roller bearings 3| in Fig. 3 but not shown, for here again a structure is provided which is identical to the mounting of the pendulum levers 28. This structure includes a shaft 5t, similar in structure to the shaft 23, supporting near the ends thereof the bearings upon which the portions 53 of the rocker arms are disposed and provided with a spacing sleeve 55 of like structure to the spacing sleeves 38 and dl, with end flanges 55 apertured to receive screws not shown but similar to the screws 35 and 35 of Fig. 3 to secure the flanges 56 of the spacing sleeve 55 to the portions 53 of the rocker arms 59 and also to end plates 5?, closing the ends of this assembly. The outer ends of the shaft 54 project through the lower ends of the pendulum levers 48 and receive nuts 58 and lock washers 59 to secure the pendulum levers against displacement on the shaft 54 yet permit relative movement between the shaft and the pendulum levers.

The forward portions of the rocker arms 58, that is, those portions extending forwardly from the stub shafts 48, support stub shafts 58 which in turn support bearings 8|, similar bearings 32 being also provided for the supporting of the stub shafts 48 in the lower ends of the pendulum levers 28. A support 53 has end portions 33 projecting forwardly at right angles therefrom with apertured end portions 55 in which the bearings 5| are mounted, completing the mounting of the support 63 upon the stub shafts 68. In the face of the support 53 an arcuate groove 8l is formed to receive tongue portions 88 of a table supporting member 89 and also tongue-shaped heads 19 and bolts 1| (Figs. 1 and 14), the latter projecting through an aperture in the table supporting member through a sleeve 12, where it is provided with a wing nut 'i3 serving to lock the table supporting member in any desired position relative to the support 53.

The table supporting member 59 is of the contour illustrated in Figs. 1 and 2 and has angularly projecting or dovetail portions 'I5 extending longitudinally thereof and receivable in a dovetail groove i6 (Figs. 1 and 8) of a table 18. The table 78 has a downwardly projecting portion 19 (Fig. 8) with a threaded aperture therethrough to serve as a nut for a traversing screw 80. The table 'I8 is, therefore, connected to the supporting member 69 through the dovetail portions l5 and the dovetail groove 16, which permit the movement of the table relative to the supporting member 69 by rotation of the traversing screw 80. The upper portion of the table 18 is square in general contour, having a raised circular portion 83 providing a flat surface upon which work 84, which in the present instance is a quartz crystal blank, may be mounted by any suitable means such as cement, indicated at 85 in Fig. 8. The circular portion 83 of the table has a central shank 8| extending through an aperture in the table proper 18 to support the portion 83 for circular adjustment. A hand-operated lock screw 88 carried by the table is positioned to engage the shank 8| to lock the portion 83 in any desired position.

Attention is now directed to the traversing screw 88 and the mechanism for causing rotation thereof. The ends of the traversing screw 80, which are free of threads, are journalled in portions of the table supporting member 69 and provided with suitabie means, such as head member 81, to hold the adjusting screw against longitudinal movement. A worm gear 88 (Fig. 7) is mounted upon the traversing screw 88 adjacent one end thereof and interengages a worm 89. The worm 89 is flXedly mounted upon a shaft 80, the latter being journalled in bearings 9i of a housing 92 formed as a part of the table supporting member 69 and covered with a plate 93. The forward end of the shaft 98 (Fig. 2) projects through the housing 32 and has a hand wheel 94 mounted thereon for manual rotation of the shaft and, through the worm and worm gear, manual actuation of the traversing screw 88. The other end of the shaft 9|] has a universal joint 96 connecting it with a portion Sl of a telescoping shaft indicated generally at 98. The other portion 99 of the telescoping shaft S8 is tubular in cross-section, permitting axial movement of the shaft portions 91 and 99 relative to each other vet are provided with key or spline connections (not shown) assuring simultaneous rotation one with the other. The shaft portion 99 is connected to a shaft ||l| through a universal joint |82. The shaft lill is journalled in bearings of a base member |84 (Fig. 6) the latter being rigidly mounted upon the spacing sleeve 55. The other or rearward end of the shaft |8| has a gear |05 mounted for free rotation thereon and which interengages a pinion |86 of a motor shaft |81. The shaft |01 is from a motor |58 mounted upon the support IEM.

Returning again to the shaft 0|, a free wheeling clutch |89 is mounted thereon and formed to cause positive connection between the gear |85 and the shaft |8| when the motor is driven in one direction but to allow the gear |55 to rotate freely on the shaft when the motor is driven in the opposite direction. The clutch |89 is of the conventional type illustrated in Bulletin #131, March 2, 1937, in a. catalog published by the Hilliard Corporation, Elmira, N; Y., entitled The Hilliard Line Clutches and Couplings. In view of the fact that the clutch |09 is of a well known commercial type, it is lbelieved that a detailed illustration and description of this clutch is not necessary as long as its function is made clear. The function of the clutch, as stated above, is to cause positive connection between the gear |05 and the shaft I| when the motor is driven in one direction and to allow the gear to rotate freely on the shaft when the motor is driven in the opposite direction.

When the motor |08 is driven in one direction to cause the clutch |00 to function, lateral adjustment of the table 18 is brought about. However, during rotation of the motor |08 in the opposite direction, mean-s is actuated to cause oscillatory movement yof the table 18 through similar movement imparted to the support 83. The forward end of the motor |08 has a driving connection with a lateral shaft I I2 upon which eccentric ||3 is mounted. The driving connection between the motor |08 and the shaft ||2 is not shown but this may be composed of suitable gears disposed in the housing of the motor, to cause rotation of the shaft I|2 approximately 20 R. P. M. A link I|4 (Figs. 1, 2 and 6) has one end connected to the eccentric I3, while the other end, which has a right angle bend therein as shown in Fig` 1, is pivotally connected, at ||5, to a bracket I I6, the latter being mounted upon the rear wall of the support 63 adjacent the center thereof. Therefore, during rotation of the motor |08, the shaft ||2 is rotated with the eccentric H3, imparting movement to the link ||4 which, through the bracket IIS, will impart an oscillatory movement to the support 63 and the table 18 through the pivotal supporting means for the support 63, namely the stub shafts 60.

Attention is now directed to a cutting element |20 which is rotatably mounted upon a shaft |2| of a motor |22, the latter being supported by bearing brackets |23 connected to the `base |0 and formed to house bearings for the shaft |2I. The cutting element 20`may be of any suitable structure, which in the present instance is of the type used for cutting stone. A guard |24 is mounted to partially house the cutting element, as shown in Figs. 1 and 2, and a suitable lubricant may be directed through the guard to the cutting element from a supply line |25. It will be understood that the cutting element is disposed at a fixed position and that the work is moved relative thereto.

Description has been given as to how the table 18, supporting the work 84, may be moved laterally to position the work for successive cuts by the cutting element and how the table may be oscillated during such cutting operations. Attention is now directed to one of the means to move the table relative to the cutting element, namely the table return moving means which conditions the table feeding means for actuation. rThe table return moving means includes an arm |20 integral with one of the pendulum levers 40, the one at the left (Fig. 2), attention also being directed to Figs. 1, 4 and 5, the juncture of the arm |28 with its lever 40 being adjacent the shaft 25. The arm |28 is bent, as illustrated in Fig. 2, to present its outer end to a piston rod |29, a pivoted connection being provided between the arm and the piston rod. The piston rod |29 is connected to a piston |30 (Fig.

12) which is disposed in a cylinder |3I, the latter T0 being pivotally supported at |32 (Figs. 4 and 5) to a bracket |33, the latter being mounted upon the base |0. The cylinder I3| is provided With-air under pressure from a supply line |34 through the control of electrically operated valve |35 (Figs. 1 and 12) disposed in the line. When `the valve |35 is opened, this taking place at a time when the piston |30 is in its uppermost position, air under pressure will be supplied to the cylinder above the piston to move the piston downwardly at a speed controlled by a needle or pressure relief valve |36. Through this movement ofthe piston the piston rod |20 will be moved downwardly, imparting movement to the arm |28 to move the pendulum levers (Figs, 1, 4 and v5) forwardly (clockwise) from the position shownfin Fig. 5 to the position shown in Fig. 4, this movement imparting motion to the pendulum levers'28 through the rocker arms to move the support 63 together with the table 18 into its starting position, as illustrated in Fig. 4. This constitutes means for imparting a return movement to the table and the work thereon relative to the cutting element |20.

Means is provided to counter-balance the pendulum levers not only in their return movement but in their feeding movement, which will hereinafter be described. The counter-balancing means includes a tension spring |31 which has its lower end connected to a hook l 38 nxed to the base I0, the upper end of the spring. being oonnected to an adjustable coupling |39 which connects this end of the spring pivotally, asl at |40,

The arm |4| is formed as an integral part of the other pendulum lever 40, that is the one disposed at the right (Fig. 2) and is of the shape illustrated in this figure to position the spring |31 beyond the adjacent frame I2. Dur- Ving the oscillatory movement of the pendulum levers 40, moving the table with the work relative to the cutting element, the pivotal connection of |40 of the arm |4| and the spring |31 are moved from one side of a dead center above the shaft 25, to the other side thereof, to assist in moving the pendulum levers in either direction they are travelling as soon as the pivotal connection |40 passes the dead center point. The spring |31 therefore, functions to counter-balance the pendulum levers, adding its force to the movement of the levers in either direction to bring about a predetermined feeding pressure effective to move the table and its work relative to the cutting element.

Attention is now directed to the means for moving the table and its associated structures in the feeding direction to move the work relative to the cutting element, to cause the cutting element to cut a path through the work. This feeding means includes a spring |44 which provides the force to move the table and its supporting structures in the feeding direction. The spring |44 has one end connected to a bar |45, the latter being adjustably connected to a wall of the base I0. the spring also being partially housed in the base. The other end of the spring is provided with a circular coil |46 through which a rod |41 extends. The rod |41 is threaded and extends through a sleeve |48, where the rod is provided with nuts !49 which cooperate with the rod in providing an adjustment to vary the force of the spring |44. The outer end of the rod |41 is connected to a strip |50 which extends almost completely about an eccentric-like block 5|, where its inner end is xed to the block by suitable means such as screws |52. The block |5| is ofthe contour shown in Fig. 1 and is mounted upon a shaft |53 which is journalled in suitable bearings (not shown) disposed in a sleeve |54 (Fig. 2), the latter being supported by arms |55 .of a bracket |56 mounted upon the rear wall of the base |0. As illustrated in Fig. 2, the shaft |53 is of sufficient length to extend to a position near the center line of the apparatus, where a substantially semi-cylindrical element |58 is mounted thereon for rotation therewith. The element |58 has a strip |59 xed thereto, as at |60 (Fig. l), and extends inwardly to a point where it is fixed to a pin |6| (Fig. 2), the latter being rotatably supported in the end of an arm |62 supported by or made integral with the sleeve 55. Through this structure it will be apparent that during the return movement of the table and its associated mechanism the sleeve 55 is moved forwardly with the arm |82, the pin and the strip |59, causing rotation of the element |58 and the shaft |58 a denite distance to cause expansion of the spring |44, through the block |5| and the strip |58, conditioning this means, including the creation of a desired force in the spring, to function in imparting a feeding motion to the table and the work when the proper time in the operating cycle of the apparatus arrives. The strips |50 and |59 may be of any suitable structure such as woven fabric, sheet metal or the like. During the rotation of the shaft |53 oscillatory movement is imparted to a plurality of switch arms |83, |84 and |55 to operate switches |66, |61 and |88 respectively, the function of these switches being hereinafter described.

Attention is now directed to Fig. 12, which illustrates a simple electrical circuit to control the motor |08 and the valve |35. Supply lines |10 and |1| lead into a magnetic switch |12, the operation of which is controlled through a manually operable switch |13. The valve |35 is operated through the energization of a coil which is included in an electrical circuit when a relay |18 is energized to close a switch |11. The relay |18,

however, is under the control of the limit switch |61 (Figs. 2 and 12), When the limit switch |81 is closed, through the actuation of its respective switch arm |85 (Figs, 1 and 12) a circuit is completed from the magnetic switch |12 through conductor |19, the switch |81, the relay |18, back to the switch |12, to conductor |80. The energization of the relay |18 will close the switch |11, completing a circuit through the coil |15 through connection with the conductors |19 and I 80, respectively.

The motor |08 is electrically connected to the source of electrical energy, that is the leads |10 and |1|y through the switch |12, by an electrical circuit which includes an electrically operated reversing switch indicated generally at |82, a thermo time delay relay |83 and an automatic time switch |84 in addition to the limit switches |68 and |65. The thermo time delay relay |83 is in the present instance of acommerciallyknown type illustrated in a Catalog E. page 24E, entitled Relays-Timers published by Struthers Dunn Inc., Philadelphia, Pa. Furthermore, the automatic time switch is in the present instance of a commercially known type known as type TSA-10, illustrated on page 314 of Catalog GEA- 820A entitled Electrical Equipment for Industry published by General Electric Company. The automatic time switch is electrically connected to the switch |12 through conductors |86 and |81. connected respectively to conductors |18 and |80.

Through this switch the time in which the motor |08 is energized is controlled. The length of time desirable for the energization of the motor depends upon the distance of movement of vthe table during each half of the cycle for the size of work or blank crystal being cut, and to cause the motor to function in conjunction with the table moving means which is under the control of the magnetic valve |35. The switch |82 is moved into the position shown by a relay |88 and into a reversing position by a relay |89. The relay |83 disposed in the reversing circuit controlled by the relay |89 causes the motor |08 to rotate in a reverse direction for a limited time to render the clutch |09 operable to cause operation of the table cross feed mechanism. The reversing of the motor is further controlled by the limit switch |85 through each switch arm |83. The limit switch |68 functions at a desired interval during the operation of the apparatus, to cause resetting of the automatic time switch |84.

Attention is now directed to Fig, 13, which illustrates the functioning of different features of the apparatus during each cycle of operation thereof beginning at the eXtreme left of this figure, which point may represent the beginning of the operating cycle. From this point the table starts its feeding movement by means of the spring |44. At a point shortly spaced therefrom, representing an interval of time, the motor |08 is energized to cause its rocking motion of the table 18. This continues throughout the feeding motion of the table, moving the work relative to the cutting element. At the center of the table moving cycle, the limit switch |61 operates to open the valve |35 to admit air under pressure to the piston |30, causing return movement of the table. The piston |30 and the mechanism associated therewith act to limit the spring |44, stopping the feeding motion of the table and causing the return motion thereof. The motor |08 continues to oscillate the table during the return movement thereof excepting for a short distance near the end of such movement, indicated in Fig. 13, where the motor is stopped. At this point the limit switch |88 is operated to reset the automatic switch |80. At the completion of the return movement the limit switch |68 is closed to start the motor in reverse direction, causing the clutch |09 to function to operate the mechanism to bring about a cross feeding of the table to position the work for a new cut by the cutting element. This cross feed of the table is represented by a horizontal line connecting the end of the return movement with the point representing the beginning of the next operating cycle. At this point, that is, at the beginning of the next operating cycle, the valve |35 is closed to render inoperative the means for returning the table and for holding the table in the forward position, which in turn renders the spring |44 eiective to start the feeding movement of the table. At this .point the motor |08 is also stopped by the time delay relay, to condition the motor for starting in the opposite direction to again begin its oscillatory movement of the table.

With the diaphragm shown in Fig. 13 as a guide, the operation of the apparatus may be more clearly understood. Let it be assumed that the table 18 with its associated mechanism is in the forward position shown in Figs. l and 4, the table having been moved laterally for a new cut in the work. To start the table in its feeding direction the valve |35 is closed, render- 1ng the hydraulic means associated therewith inoperative to further move the table forwardly or to hold the table in its forward position and render the spring |44 effective to begin the feeding movement of the work toward the cutting element. The force of the spring |44 will create a pull on the strip |50 (Fig. 1), causing rotation of the shaft |53 through the association of the block causing simultaneous rotation of the element |58, which in turn creates a rearward pull on the strip |59. The pull on the strip |50 is applied to the arm |62 (Figs. 2 and 4), causing rearward movement of the sleeve 55. The sleeve 55, through its shaft 54, causes counterclockwise movement o-f the pendulum levers 28 and, through the rocker arms, causes counterclockwise movement of the `pendulum levers 40. These movements of the pendulum levers about their shafts 23 and 25 create an oscillatory movement which is imparted to the support 63 supported between the forward ends of the rocker arms 50. The combined motions 0f the pendulum levers results in the movement of the table 18, and the work mounted thereon, through an arc represented by the bottom of a cut |92 illustrated in Fig. 11. Therefore, the movement imparted to the table by the cooperation of the pendulum levers about their individual axes moves the work through the arc to cause the cutting element to leave an uncut portion beginning at an edge indicated at |93 (Fig. 11) and ending at an edge |94, the intermediate portion, however, increasing in thickness between these edges to a sucient thickness adjacent the center to support the thin plate being cut from the blank during the complete cutting operation and until all of the cuts in the blank have been completed. In cutting work such as quartz crystal, it is important that unnecessary friction between the cutting element and the work be eliminated, to avoid burning. To avoid this difficulty while making a straight cut through a quartz crystal, where the periphery of the cutting element will engage the work for a considerable distance, it is necessary to reduce the speed of rotation of the cutting element and thus the resulting speed of operation of L an apparatus, to eliminate a high degree of friction and burning. This diiculty is eliminated and the friction is reduced to a minimum by imparting an oscillatory or rocking movement to the table and thus to the work during the feeding operation. Such movement is imparted to the table and work through the motor |03, its eccentric H3, the link I4 and the bracket I6, which, during the energization of the motor, will oscillate the support 63 about its pivots, namely the stub shafts 60, rocking the table 18 and the Work 84 to move the work from the position shown in Fig. 9, where the cutting element engages the work at substantially a point contact at the bottom of the cut, to a position, illustrated in Fig. 10, where the cutting element engages the work at substantially a point contact at the top of a cut. Similar point contacts are made between the cutting element and the work throughout the rocking or oscillatory movement of the work relative to the cutting element from the point illustrated in Fig. 9 to the point illustrated in Fig. 10. This oscillatory motion is continually imparted to the work throughout the feeding operation as well as the return movement excepting for the intervals of time during each portion of the operating cycle which exist at the beginning of the feeding movement and at the end of the return movement when the motor |08 is deenergized. During the feeding moveli l) ment of the table the spring |31 functions to cancel'the weight component of the pendulum levers, to render the spring |44 effective to apply a constant force in moving the work toward the cutting element throughout the'feeding movement. l

The rotation of the shaft |53, through the force of the spring |44, imparts movement to the switch arms |63, |64 and |65 mounted thereon, these arms being adjustable to vary the time during the operating cycle of the apparatus for the actuation of their respective limit switches. At a selected time during the feeding movement of the apparatus, the limit switch |61 is closed, causing energization of the relay |18 to close the switch lll (Fig. 12), resulting in the energization 0f the coil |75 to open the valve |35. When the valve |35 is opened air under pressure is admitted to the cylinder |3 i, forcing the piston |30 downwardly, which movement is Vycontrolled by the needle or pressure relief valve |36 at the bottom of the cylinder, to cause movement of the arm |23. The arm |28, as illustrated in Fig. 5, will be moved clockwise, imparting similar movement to the pendulum levers 40, and through the association of the rocker arms 50, impart clockwise movement to the pendulum levers 28. In this manner the table 18 with the work is moved from the position shown in Fig. 5 to the position shown in Fig. 4, returning the work to the starting position, moving the work in the same arcuate path that it travelled during its feeding movement. When the table has been returned to its starting position the valve |35 remains open to hold the spring |44 ineffective to move the table until the lateral adjustment of the table has been completed. The lateral adjustment cf the table is brought about through the limit switch |66, reversing the motor |08 through the relay |89 and starting the operation of the thermo time delay relay |83. The motor |88 remains energized in this reverse direction under the control of the relay |83, causing a driving of the pinion |05 and the gear |05 in reverse directions also. This rotation of the rear |05 results in rendering the clutch |09 effective to operatively connect the gear |05 to the shaft |0|, causing rotation of the telescoping shaft 98 to rotate the worm 89 (Figs. 2, 6 and '7). The rotation of the worm 89 causes rotation of the worm gear 88 and similar rotation of the adjusting screw 80. Through the rotation of the adjusting screw a nut '|9 (Fig. 8) is caused to travel laterally to the left (Fig. 2) a distance controlled by the relay |83 to move the work 84 laterally a distance desirable for the next cut. When this has been accomplished the relay |83 will close the circuit to the motor |08, deenergizing the motor and thus stopping lateral motion of the table. At this time the valve |35 is closed, rendering the spring |44 effective to again move the table through the feeding cycle of the operation of the apparatus.

Mention was made during the previous feeding cycle of the spring |31 cancelling the weight component of the pendulum levers to render the spring |44 effective to apply a constant force to the material throughout the feeding cycle. To more fully understand the function of the spring |44 and its connecting means with the table, attention is directed to the block |5| and its connection with the spring through the strap |50. The contour of the block |5| is such that, as the force of the spring |44 diminishes, during the feeding cycle, a lever arm, existing through the strap |55 and the block, between the spring and the shaft l53 increases proportionately to the diminishing force of the spring to cause application of the constant force to operate the mechanism, associated with the shaft, to move the table. The length of the lever arm may be measured along a vertical line extending from the center of the shaft to the point where such line would intersect the strap beneath the shaft. To illustrate, if it were possible to further rotate the block clockwise and cause the straight portion of the strap |50 from the spring to intersect the aXis of the shaft |53, the length of the lever arm would be nil. In such a position there would not exist suflicient force in the spring to rotate the shaft, as the connection thereof with the block would be on dead center with the shaft. As this connection moves further from the dead center position, the lever arm increases in length to its greatest length which exists when the eX- treme left of the lower or iiat portion of the .block is in a vertical plane with the axis oi the shaft. Thus, from the position of the block shown in Fig. 1 to that just described, the lever arm increases in length proportionately to the diminishing force of the spring to translate the varying spring force into a constant force at the table. The spring l3'l functions in the same manner during the return movement of the table, assisting the pneumatic means, namely the piston i3d) and its associated parts, to apply a constant force in moving the table and the work to the starting position.

It will be understood that during the operation of the apparatus the motor E22 remains energized., causing continuous rotation of the cutting element, during which time a suitable lubricant may be applied thereto through the supply line |25.

Prior to the cutting of the crystal blank the blank is examined to determine the direction of the grain therein and the blank is marked to indicate the same. After the .blank is mounted on the table, the table is adjusted to cause the direction of the grain of the work to be parallel with the cutting element. This adjustment may be brought about through the loosening of the wing nuts i3 (Fig. 1), loosening the bolts 70 (Fig. 14) to permit desired movement of the table supporting member 65 relative to the support 63 which is controlled by the arcuate ribs of the former, riding in the arcuate groove of the latter, and the similar movement of the bolts 'l0 to the desired position, after which the wing nuts 13 may be tightened to secure the table supporting member in the adjusted position on the support.

During the operation of the apparatus, it will be understood that two oscillatory movements are imparted to the table, one through the cooperating movements of the pendulum levers and their associated rocker arms to cause formation of the arcuate cut through the work, as illustrated in Fig. 11, the other oscillatory movement being repeatedly applied to the work to constantly shift the point of engagement of the work with the cutting element to cause the arc of the cut to be greater than the engaging arc of the cutting element, to result in substantially point contact between the cutting element and the work. Furthermore, the moving means to move the table relative to the cutting element is not only variable through the adjustment of the nuts on the rods It and 41 for varying the force of the spring |44 and the adjustment of the valves associated with the cylinder for varying the eiective force of the piston |30, but each force, whether it be the pneumatic means or the spring forcing means, is of the nature of a cushioned force applied to the work.

The embodiment of the invention herein dis.- closed is merely illustrative and may be modified and departed from in various ways Without de-v parting from the spirit and scope of the invention as pointed out in and limited only by the appended claims.

What is claimed is:

1. In a cutting apparatus, a rotary cutting element, a table to support work to be cut by the element, an operable mechanism connected to the table, a spring having a given starting force diminishing when utilized to actuate the mechanism, and means operatively connecting the spring to the mechanism and adapted to convert the diminishing force received thereby from the spring into a constant force transmitted thereby to the mechanism to cause operation of the mechanism to move the table in a direction to feed the work to the element under a constant force to cause the element to cut through the work.

2. In a cutting apparatus, a rotary cutting element, a table to support Work to be cut by the element, an operable mechanism connected to the table, a spring having a given starting force diminishing when utilized to actuate the mechanism, means operatively connecting the spring to the mechanism and adapted to convert the diminishing force received thereby from the spring into a constant force transmitted thereby to the mechanism to cause operation of the mechanism to move the table in a direction to feed the work to the element under a constant force to cause the element to cut through the work, and means to cause operation of the mechanism and connecting means to move the table in the opposite direction and to restore the given force in the spring.

3. In a cutting apparatus, a rotary cutting element, a table to support work to be cut by the element, an operable mechanism connected to the table, a spring. having a given starting force diminishing when utilized to actuate the mechanism, and a movable member operatively connecting the spring to the mechanism and havingk an effective lever arm which increases proportionately to the diminishing force of the spring to cause application of a constant force to ope'rate the mechanism to move the table in a direction to feed the Work to the element under a constant force to cause the element to cut through the work.

4. In a cutting apparatus, a rotary cutting element, a table to support Work to be cut by the element, an operable mechanism connected to the table, a spring having a given starting force diminishing when utilized to actuate the mechanism, a movable member operatively connecting the spring to the mechanism and having an effective lever arm which increases proportionately to the diminishing force of the spring to cause application of a constant force to operate the mechanism tomove the table in av direction to feed the work to the element under a constant force to cause the element to cut through the work, and means to cause operation of the mechanism and movable member to move the table in a reverse direction and to restore the given force in the spring,

DANIEL V. WATERS.

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