US2326661A - Truing apparatus - Google Patents

Description

Aug. 10, 1943. 1.. .1. LALlME TRUING APPARATUS 4 Sheets-Sheet 1' Filed Apri l 25, 1942 Aug. 10, 1943. L. J. LALIME TRUING APPARATUS Filed April 25, 1942 4 Sheets-Sheet 2 alt Z Ed;

Int/emf to? #i/ Aug. 10, 1943. JJLALIME TRUING APPARATUS 4 Sheets-Sheet 3 Filed April 25, 1942 mww @ m NY P W @m 4 Sheets-Sheet 4 A 0, 1943. L. .1. LAL IME TRUING APPARATUS Filed April 25, 1942 Patented Aug. 10, 1943 T me APPARATUS Lesterr. Lalime, Providence, n. 1.. assignor to Y Brown and Sharpe Manufacturing Company,

a corporation of Rhode Island- Y 'ApplicationApril25,1942,SerialNo. 440,473

s Claims. (o1.'125 11) The invention relates to grinding machines, and more particularly :to a grinding wheel truing apparatus for generating-a predetermined form on the operative face ofthe grinding wheel.

In order to grind or finish certain types of curved surfaces, it is necessary to'employ a grind ing wheel having the operative face thereof shapedor formedto produce the desired curve. In instances of this type the accuracy andfineness of finish of the ground surface is dependent upon the quality of the grinding wheel employed, and particularly upon the accurate shaping of the formed grinding surface. Forprecision work in which tolerances. of as little as a few ten thousandths of an inch may be permitted, it be comes of the greatest importance to provide truing apparatus capable of shaping the operating surface with precision and accuracy atfrequent intervals during the operation of the machine.

It is a principal object of the invention to provide in a grinding wheel truing apparatus having a diamond point truing tool movablelfor generating an irregular contour. on the operative face of a grinding wheel, a novel construction and arrangement of the supporting and actuating mechanism which is capableofprovidinga rigid isLa somewhat fragmentary view in front eleva tion illustrating particularly the truing appara tus and its supporting standard mounted onthe wheel slide; Fig. is a plan view of substantially the parts shown in Fig. 4; Fig. 6 :is an enlarged View partly in section and with the parts broken advance along its predetermined path at a constant' slow rate, and in accordance with apredetermined truing' cycle of operation.

With these and other objectsin View as may hereinafter appear, the several features ofgthe invention consist in the device's, combinations and arrangement of parts hereinafter descriebd and claimed, which together withthe advantages to be obtained thereby will be readily understood by'one skilled in the art from the .following'da scription taken in connection with the accom:

away in leftside elevation to illustrate partioua larly the wheel truing apparatuaithe control dogs 1 for the truing apparatus motor being shown out of position, the true position being shown .in Fig.9; Fig. '7 is a detail view in elevation and taken on the line 1- Tof Fig. 6; Fig. 8. is an enlarged detail view partlyin section of tl1e.dia-. mond tool holder, its supporting guidewayand the former or templet; Fig.- 9 is a. detail sectional view taken on the line 99 of Fig. 7, illustrating particularly the dogs and: the switch connectionsfor reversing and forisubsequently stopping the truing apparatusmotor; and Fig. 10 is a diagram of the'electrical operating connections for the machine.=-;-' .l

The invention is herein disclosed asembodied in a grinding machine which .may be 1 of well known description; comprising a base 10,,a Work support l2 mounted forreciprocatory movement on ways it on the base, a headstock l6 andia rootstock i8 carried on the work support l2, a grinding wheel 20, a grinding wheel spindle 22; and wheel spindle carriage 24 carried onways- 26 on the base it for moving the grinding wheel toward and away from the work... Power operation of, the several supports and cooperating mechanisms is effected by means of several electric motors whichinclude' a support motor 28 for rotating thework, a coolant motor 32 generally inclicated at 33in the electrical .diagram, and 7 a wheel spindle motor 34 connected .tojdrive the spindle 22 and: grinding wheel 29. ;The present' machine is providedwitha cross feed mechanism for 'moving the .grindingwheel toand. from the work which maybe substantiallyisimil'ar to that shown in? the patentyto Mathewson and Krause No. 2,165,898, and is therefore not here specifically illustrated. 1 I w .In carrying out .thepresent invention, applicant provides a wheel truing apparatus adapted for 'truing or dressing a grinding wheel, the

abrading surface of which is'o-f irregular outline in cross section, for'the performance of]a-p'ar ticular' grinding operation. Thetruin g appara tus disclosed in the drawings,- is of the ge'neral type which comprisesa support rotatable about an axis substantially normal to theplane'of move NT 1 Oman; i

ment followed by the tool during its traverse of the grinding surface. A truing tool holder is slidably mounted on the support for movement with the support, and for movement radially of the support axis in accordance with the dictation of a relatively stationary templet or former, which causes the tool holder, during the rotational illustrated in the drawings, the truing apparatus is supported on the wheel carriage in such a position that the pivotal axis for the tool holder support extends rearwardly on a line nearlytangential to the upper surface of'the grinding wheel,

port for the forward end of a hollow pivot shaft 48 and a former or templet 50 hereinafter to be more fully described. A rearward extension 52 of the bracket 40 provides support for the rear end of the pivot shaft 48, and also for the driving and control mechanism for the truing apparatus.

- The pivot shaft 48 is arranged to receive thereon the sleeve hub'portion 54 of a swingable tool holder support 55. Two ball bearings 58 carried on the pivot shaft 48 are arranged for engagement within the sleeve hub portion 54 of thetool holder support 56, and serve to provide and the tool holder is supported to move in' a i semi-circular are over and across the upper edge illustrated construction, coolant is supplied to the point'of operation of the truing tool by means of a coolant supply line which extends through the hollow pivot shaft on which the tool holder support is mounted to turn. V

In accordance witha feature of the invention, applicants truing apparatus isiarranged to be power operated by means of a slow speed electric motor, and a worm'and worm gear connection therefrom which drives the truing tool at a rate of approximately two inchesper minute; Electrical operating controls are provided for causing the truing apparatus to operatein accordance with a semi-automatic cycle of operation, in which the truing tool is moved in a semi-circular.

- path from one side of the grinding wheeltothe other, and is then returned to starting position. The tool holder support is balanced on its axis by means of a counterweight to avoid variations in the; load on the driving gconnectionsuwhich might otherwise have some tendency tohurry or .to retard the swinging movement of the truing tool holder supported with consequent in-; juriousvariation in the'rate of feed of the truing tool. ,7 s r 7 Another feature of the invention consists i-n the construction and arrangement of the tool holder and its supporting guideway to provide a supportlof extreme rigidity for the diamond point ttool,vwhile,at the same-time permitting: complete freedom of movement of; the tool toward and away from the grinding wheel in accordassociated therewith; v

rApplicants improved wheel truing apparatus comprises a standard 38 mounted on a platform 39onthe wheel spindle carriage 24, and a bracket Mlwhich is fitted for vertical adjustment in ways 4l' in the standard. Vertical adjustment of thaposition of the bracket 40 is obtained by means of an adjusting screw 42 threaded into a nut 43 in the bracket 40 and supported adjacent itsupperend in an end thrust bearing'45 carried on a plate 44 secured to thestandard A hand wheel 46 secured to the upper end of the adjusting-screw 42 provides convenient me ns 7 ance with the dictation of the templet or former for adjusting the vertical position of the tool a sturdy, tight fitting pivotal support for the too-l holder-support 55. An angular bracket 59 formed on the forward end of the tool holder support 56 has secured thereto a box-like guideway generally designated at 60 to receive a tool holder 64 which is supported therein for sliding movement in a plane transverse. to the axis of rotation of the tool holder support 55. Thetool holder 64 is Drovided at its lower end with a vertically extending bore 56 to receive the usual diamondtruing tool '68 which is securely held in place by means of two clamping screws 10. There is also provided adjacent the lower end of the tool holder 64, a'iollower roll 12 which is arranged for engagement with t the templet or formertflvcarried on the forwardend of the bracket 41. v In accordance with a feature of the invention, the guideway 60 and toolvholder .64 supported therein are particularly constructed and. arranged to .provide a frictionless sliding support for the tool holder which will secure a maximum rigidity of support for thetruing tool duringthe truingoperationwhile permitting the tooltobe moved in accordance vwiththe dictation ofl'the former or templet as the truing tool support 56 is turned on its axis. The guideway 69 specifically takes the form of an L-shaped plate, which is'bolted into an angular bracket formed on the support 5%; and hasformed on th inner faces thereof two guide surfaces 14 and T6 of the guideway. The remaining two sides of the'box-like guideway Gilconsists of two plates 18 and 80, the plate 18 having formed on the inner face thereof the guide surface -82, and the plate having formed 'on the'inner surfac thereof the guide surface 84. The plates 18 and 83 are supported at the top and bottom respectively between two cover plates 86 and 8B which are rigidly secured to th L-shaped plate'forming the body portion of the guideway '80. The plate 18 is held in position by means of a bolt 9!) and a nut 92 which are'anchored'fat opposite [ends in the plate l8 and in the side'of the fixed portion of thehouse ing having the'face 14' formed therein. ,The'

vided in the tool holder 64 to receive the bolts 90 and 94, so that the tool holder is permitted to move freely in an axial direction with relation thereto. 4

The left andright sides of'the tool holder 64 are provided each with three roller bearings for engagement respectively with the faces 14 and 82 of the guideway. As best shown in Figs.-2,- 3

and 8 of the drawings,-the tool holder is supported withrelation to the left side wall by means of three roller bearings 91, onebeing'provided at the upper end of-the tool holder, and two being provided at the lower end of the tool holder. .Theright side, of the tool holder is provided with three roller bearings 98 for engag'e ment with the face plate 32, two roller bearings theroller bearings :eabeing provided for -engagement with .the face plate I6. 7, I

The tool holder 64 is held with the follower roll 72' in continuous engagement with the former or templet 50 by means of a compression spring IBI which is seated within a downwardly extending bore I62 formed 'in the upper portion of the tool holder, and engages against the cover plate 86. With the construction and arrange: ment of the tool holder 64 and guideway fill above set forth, it will be evident that an extremely rigid support is provided forthe diamond tool, which will avoid possibledeflection of the tool in any direction from its correct position while permitting the tool to be movedin its guideway substantially without frictional resistance and with exactness in accordance with the dictation of the former 5G.

During the truing operation, thettool holder support 56 will rotate through substantially l80 from a position in which the tool holder is located at one side'of its axis to a corresponding position in which the tool holder is located'at the other side of its axis, and will then rotate in the opposite direction to the initial position. In order that the parts may be properly balanced to insure a continuous even rotational movement of the support 55 for feeding the tool during the truing operation, a counterbalancing weight 33 is secured to the sleeve hub 54 of the supportit, so that the support 56 will be substantially in 1 balance irrespective of its angular position.

In accordance with another featureof the invention; applicant provides power driving means which is adaptedwhen thrown into operation to impart a 180 and return rotational movement to the tool holder support 56 at an extremely slow truing rate of'feed to effect the truing or dressing of the wheel.- As previously noted, it isv of the greatest importance that the dressing tool be advanced at an even rate of feed in order to avoid unevenness or variation in the depth of cut Y taken by the truing tool, and to avoid roughness I06 is connected by means of a sleeve joint with a shaft I68 having mounted thereon a worm IIB which meshes with a worm gear I I2 secured to a sleeve element I I6 which is secured to and forms a rearward extension of the sleeve hub 5d of the j A downward extension of the housing MI of one revolution per minute. T As hereinafter more fully setforth in connection with theelectrical diagram,- the motor I04 r is arranged to be electrically reversed at the end of rotation of the tool holder, support .56

by the action'of a. micro-switch HEX-and is subsequently disconnected to render the truing'ap- Y paratus inoperative after the tool'holder support 55 has moved through 180 in the reverse; direction by the action- 0f a second micro-switch H3. The switches aregrendered operative respectively, by the action of dogs E20 and "I22: which are adjustably secured in annular T shaped tracksuformed in the, opposite facesof a micro-switches ill} and IIB respectively. Ap-' plicants improved truing attachment is encased within-a housing MI which fits over the tool holder support or ar nfili and the guideway 60,

and isfitted at its rear sideagainst sleeve hub 54.

cases-. the counterweight I03. a, a Infaccordance with a feature of the present invention, the truing; attachment is constructed.

and arran ed to provide means for supplying I coolant. atfthe point of contact 'of'the truing tool,

with the grinding wheel without interferingwith the swinging movements of the truing tool holder Stand support Efiabout thepivotshaft 23. In

the illustrated construction,.,the-pivot shaft 48 is hollow, and is extended'forwardly to a "point closely adjacent'the upper edge of the grinding wheel, so that coolant passing through the bore shown) in the base of the machine throughaa flexible hose connection I40 which is' connected I with tlierear end of'the hollow shaft 38.

j The truing attachment provided with the present'machine is arrangedfto' be electrically, controlled to operate in accordancewith a semi-1 automatic cycle or operation; The electrical? operating connections for the machine including "specifically theloperating connections 'for the wheel truing apparatus, will be briefly described in connection with the elementary'diagrani of the electrical apparatus for driving and for con" trolling the operation of the machine inFig. 10.

As will'be evident 'from an inspection of this figure, "power is supplied through mainline c on. I

nectio'ns LI, L2, L3 andILfl' to the wheel spindle motor 3 the wheel; slide'motor I62, the. work support motor 28, he coolant pump motor 32,

andthe headstock spindle motor 3 8', For'startin'gja'nd'stopping all of these'motorsja main relay control switch-M is provided having switch contacts across the main line. A secondary re lay switch LE having contacts across the main line is operative to vstart and stop the coolant pump motor and the headstock spindle motor. The control-circuit for-the-n'iachine includes additionally the directional relay switches F and B forcontrolling the position ofthe wheel slide "Y 1 motor, the secondary relayswitches RCand WS, 7 manually operable machiriemain start'and stop support is rotated to advance the'jtool 'at the rate Ihe dogs I20 .and I22 are arranged as follows: 7

' 20-24 and to close contact IS-N.

switches-I44, 14s, a wheel slide-switch m, anda grind-true switch I48. i i

The operation of the severaloperating controls for the machine above noted,"- while similar in many respects to the electrical operating controls illustrated in the Patent No. 2,165,898 to Mathewson and Krause will be briefly described The pressing of the main start switch I energizes relay M or the main starting switch, thus putting in operation the wheel spindle motor '34 and the work support motor 28; Contact MI-2 closes, forming a holding circuit. Assuming that the grind-true selector switch I48 is in the-grind position, a movement of the cross feed hand wheel from its retracted position will actto shift the hand wheel switch I", causing contact I8-4 to be opened, and contact 3-5 to be closed.

For a full disclosure of the hand wheel switch I41 and the actuating connections therefor not here specifically illustrated, reference may be had to the patent to Mathewson and Krause No. 2,165,898, above noted. As will be evident from the elementary diagram, the closing of the switch contact 3-5 causes relay LE to be energized, starting the coolant pump motor 32 and the headstock spindle motor 4!]. Relay WS remainsenergize'd through the operation of a holding circuit Relay RC is relay F is energized to close the wheel slide motor forward switch. The wheel slide motor starts, and continues in operation until arrested by the operation of the wheel slide limit switch which moves to open contact Iii-24 and to close contact 20-24. Return of the cross feed hand wheel to its retracted position at the completion of the grinding operation, causes the hand wheel switch 411 tobe returned to its initial position, opening contact 3-5 and closing contact Iii-4. Relay RC' is now de-energized, causing RC contact 21-22 toopen andRC'contact 2I-23 to close. Relay 3 is energized, starting the wheel slide motor which operates to return the wheel slide to its retracted position, at which time the wheel slide limit switch is again shiftedto opencontact Relay LE is deenergized, stopping the coolant motoraia d headstock motor 3! f e 3 Movement of the" grind trueswitch I48 to the truepcsition serves to. render the hand wheel switch 41 inoperative, causes relay WS to be (lo-energized to prevent forward movement of the wheel slide, and causes relays LE and R0 to be energized, thus starting the coolant pump motor and headstock motor.

L The' truing attachment motor lfi dof applicants improved construction- 'is connected across the control circuit above, noted, and is arranged 'to be controlled by means of a number of switch connections which are operable independently of those above described, and include relay actuated trui'ng motor start switches R and Lior starting thetruing apparatus respectively to the rightand to the left, manual 'truing apparatus start right and left switches I53, I52, 3, 'dog' actuated switch -I'I6 for reversing the truing motor at the end of e the 'truing movementv to the right, a dog actuated 'truing motor stop switch H8, and a manually l and tool holder 64, the dog I29 will-engage with "so that relay L is'de-energized, contacts L3-I-40,

IRS-I0 and L29-3Elopen and the truing apparatus motor I04 stops. The truing motor stop switch I55 is maintained in-its stop position.

Micro-switch I HS will in the meantime have returned to its initial position as the dog I20 ridesofi the actuating" arm. -It may be noted that applicants truing attachmerit "for truing formed operating surfaces on grinding wheels ma be rendered operative independently of whether the grinding wheel is in an advanced or a retracted position, since the truing attachment is mounted upon the wheel slide and is arranged to engage with the upper sideof the grinding wheel, and thus avoids any possibility of interference with work which may be placed in themachine.

It will be understood that tie invention is not limited to the specific embodiment shown, and that various deviations may be made therefrom without-departing fromthe spirit and scope of the appended claims. 7

What is claimed is:

l. n timing apparatus for a grinding machine having .a' longitudinally movable table and a transversely movable wheel slide comprising a standard on the wheel slide, a bracket adjustable on the standard to adjust the truing apparatus toward and away from the grinding wheel, a support'pivotally'mounted on the bracket to swingin a circular path, a truing tool holder transversely movable on the support, a'former mounted on the bracket to move the holder transversely relative to the support as the support is swung about itspivot to cause thetruing tool to produce apredetermined.shape,onjthe grinding wheel periphery, power actuated means with 'the'supp'or't, an electric motor connected to 1 drive the .worm'reversibly in either direction, and means operative upon movement of the support toa predetermined angular position in one direction to reverse the direction of drive.

2. A truing apparatus for a'grindin machine comprising a' bracket located on the grinding machine in predetermined relation to thegrind ing" wheel, a' support pivotally mounted on the bracket'to swing in a circular path,"a truing tool holder transversely slidableon the support, means 7 including a former 'arranged to move the truing tool holder transversely relative to the support as the support isiswung about itspivot to cause the truing tool toprodu'ce a predetermined shape on the grinding wheel periphery, a 'slow'speed roversible electric motor, a worm and worm wheel connection from the motor for rotating the support, and control means for the motor including a switch and a follower element rendered operative by the rotation of the support, saidworm wheel being supported to turn co-axially and as a unit with the support through a predetermined angle to reverse the motor, and a second switch andfollower element rendered operative by the return of the support to its initial position to stop the motor. r

3. A truing apparatus for a grinding machine comprising a bracket located on the grinding machine in a predetermined position with relation to the grinding wheel, a support pivotally mounted on the bracket to swing about a substantially horizontal axis, a tool holder mounted on the support to swing therewith in a circular path and movable transversely on the support,

' means including a former and spring means for maintaining the holder in operative relation to the former for controlling the position of the tool holder on the support during the swinging movement of the support to cause the tool to follow a predetermined outline, a counterweight on the support for balancing the support on its axis for any angular position, and power means comprising a slow speed reversible electric motor, and a worm and a worm wheel co-axial with the support 7 pivot connected for rotating the support at a slow truing rate to effect the truing operation.

4. A truing apparatus for a grinding machine having a grinding wheel, a bracket located in a predetermined position with relation to the grinding wheel, a hollow pivot. shaft on the bracket extending substantially tangentially from the grindin wheel, an overarm support pivoted to turn on said pivot shaft, a truing tool holder carried on said overarm support for swinging movement therewith and formovement trans-j.

versely on the support toward and away from the grinding wheel, and means including a former on the bracket for controlling the position of the tool holder on the support during the swinging movement of the support to cause the tool to follow a predetermined outline, power means for rotating the support to effect a truing operation,

and a supply connection with said hollow pivot shaft whereby coolant issupplied through said hollow shaft to the point :of operation of the truing tool.

5. A truing apparatus for a grinding machine said hollow pivot shaft whereby coolant is supplied through said hollow shaft tothepoint'of operation of the truing tool. r

6. A truing apparatus'for a grinding machine comprising. ,a bracket, means to; support the bracket on the grinding machine, a pivotally mounted support which is arranged to'swing' in a circular path, a transversely movable truing tool holder carried on said support, anti-friction roller bearingsand guide surfaces cooperating therewith to provide anti-friction sliding support for the truing tool holder on its support, said guide surfaces and roller bearings being disposed in I opposed positions longitudinally of and transversely of said pathto provide a direct antifriction support for the truing tool holder in its guided path against deflection in any direction, tightening means for relatively adjusting each of said longitudinally and transversely opposed guide surfaces and the engaged roller bearings to maintain a tight fit .therebetween, a former controlling the position of the-tool holder on the support during swinging movement of the support to cause the tool to, follow a' predetermined outline, and yieldable means for maintaining the tool holder in operative relation with the former.

for saidpairs of opposed guide faces for subjecting the tool holder to an engaging pressure therebetween, a former acting on the tool holder to, move the holder in said guideway transversely relative to the support as the support is swung about its pivot to cause the truing tool to produce a predetermined shape on the grinding wheel periphery, and yieldable means for maintaining the .tool holder in operative relation with the former.

8. In a truing apparatus fora grinding machine having a support and means for effecting move-- ment of the support transversely of the operating face of the grinding wheel, a truing tool holder movable on the support toward and away from having a grinding wheel rotatable on a. horizontal axis, and a grinding wheel carriage, a bracket located on the carriage in a predetermined positiori with relation 'to the grinding wheel, a hollow pivot shaft on the bracket extending rearwardly substantially horizontally and tangentially from the grinding wheel, an overarm support pivoted to turn on said pivot shaft, a truing tool holder carried on said overarm support for swinging movement therewith and for movement transversely on the support toward and away from the grinding wheel, and means including a former on the bracket for controlling the position of the tool holder on the support during the swinging movement of the support to cause the tool to follow a predetermined outline, power means for rotating the support to effect a truing operation, and a supply connection with the operating surface of the grinding wheel, and

means including a former and spring means for maintaining the tool holder in contact with said former for causing the tool during movement .of the support to generate a predetermined shape on the operating face of the grindin wheel, the

combination of a four-sided guideway on the support comprising two fixed guide surfaces set at right angles to one another and two elements having guide surfaces thereon, each adjustable toward and away from an oppositely facing fixed guide surface, anti-friction roller bearings on the truing toolholder engaging each of said fixed and opposed guide surfaces, and tightening means,

for moving each of said movable elements and guide faces thereon toward the oppositely facing a guide surface forsubjecting the tool holderto an engaging pressure therebetween.

' LESTER J l LALIME. I I

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