US2819566A - Hone expansion control mechanism - Google Patents

Description

Jan. 14, 1958 A. M. JCHNSdN 2, 66

HONE EXPANSION CONTROL MECHANISM Filed Jan. s, 1956 B SheetS-Sheet 1 m lllllllllllil mag o l O/YL Q'f knJow L a, W, my uwrw Jan. 1958 A. M. JOHNSON 2,819,566

HONE EXPANSION CONTROL MECHANISM Filed Jan. 3, 1956 8 Sheets-Sheet 2 F -"pg- 3 w 7 wsmm.

Jan. 14, 1958 A. M. JOHNSON HONE EXPANSION CONTROL MECHANISM 8 Sheets-Sheet 5 Filed Jan. 3, 1956 Jan. 14, 1958 A. M. JOHNSON 2,819,565

r HONE EXPANSIQN CONTROL MECHANISM Filed Jan. 5, 1956 8 Sheets-Sheet 4 llll' IHII I lf G0 fllbefe dohvwrovu CfiTTORME Y/ 1953 A. M. JOHNSON 66 HONE EXPANSION CONTROL MECHANISM Filed Jan. 3, 1956 8 Sheets-Sheet a ENVEMTOM Jan. 14, 1958 A. M'. JOHNSON 2,819,566

HONE EXPANSION CONTROL MECHANISM Filed Jan. 3, 1956 V 8 Sheets-Sheet 6 imvezu- OMB-edhvwom OTTO Jan. 14, 1958 A. M. JOHNSON 2,319,556

HONE EXPANSION CONTROL MECHANISM v Filed Jan. 3, 1956 8 Sheets-Sheet 7 CYCLE Jan. 14, 1958 A. M. JOHNSON 2,819,566

HONE EXPANSION CONTROL MECHANISM Filed Jan. 5 1956 j 8 Sheets-Sheet 8 United States Paten'tO 2,819,566 HONE EXPANSION CONTROL MECHANISM Albert M. Johnson, Rockford, 11]., assignor to Barnes Drill Co., Rockford, Ill., a corporation of Illinois Application January 3, 1956, Serial No. 557,116

9 Claims. (Cl. 51--1S4.3)

This invention relates to a high production machine for honing cylindrical surfaces on duplicate workpieces in successive cycles which, in the case of an internal work surface, consists in first rapidly expanding the honing tool within the work bore, continuing the expansion at a slow rate during reciprocation of the tool in the bore until the latter has been enlarged to the desired size, and then rapidly collapsing the tool preparatory to its withdrawal from the workpiece.

One object is to control the termination of the rapid expansion in a novel manner such as to minimize the time required for each honing cycle while at the same time avoiding engagement between the abrasive surface of the tool and the bore wall while the tool is being expanded at the rapid rate.

A more detailed object is to terminate the rapid expansion with the abrasive surface spaced short of the bore wall by an amount which remains substantially fixed in successive cycles irrespective of the Wearing off of the abrasive surface.

The invention also resides in the novel manner of sensing the wearing oil of the abrasive surface and correspondingly varying the successive cycles to interrupt the rapid expansion at the proper point in each cycle.

A further object is to utilize the improved control mechanism in a novel manner to signal wearing out of the abrasive elements of the honing tool.

Another object is to provide a novel means for conditioning the control mechanism for proper operation following replacement of worn out honing stones.

Other objects and advantages of the invention will become apparent from the following detailed description taken in connection with the accompanying drawings, in which Figure 1 is a fragmentary elevational view, with certain parts in section, of a honing machine embodying the novel features of the present invention.

Fig. 2 is a fragmentary section taken along the line 2-2 of Fig. 1.

Fig. 3 is a schematic view and circuit diagram.

Fig. 4 is a fragmentary view taken along the line 4-4 of Fig. 2.

Figs. 5, 6, 7, 8 and 9 are views similar to Fig. 4 illustrating different positions of the principal parts, Fig. 9 being a section along the line 99 of Fig. 2.

Figs. 10 and 11 are fragmentary views showing the relationship of the abrasive and work surfaces at different points in a honing cycle.

Fig. 12 is a view similar to Fig. 4 showing a modification.

Fig. 13 is a fragmentary view similar to Fig. 2.

Fig. 14 is a view similar to Fig. 12 with the parts in a different position.

Fig. 15 is a view similar to Fig. 3 showing the modification of Fig. 12.

Fig. 16 is a view similar to Fig. 14 indicating the different positions of the parts in the honing cycle.

.. Ice

Fig. 17 is an electric circuit diagram for use with the form of the invention shown in Fig. 3.

Fig. 18 is a similar diagram for use with the modification shown in Fig. 15.

Fig. 19 is a circuit diagram for another modification.

In the embodiment shown in the drawings for purposes of illustration, the invention is incorporated in a power actuated mechanism ltl (Figs. 1 and 3) for governing the expansion and contraction of a tool 11 for honing an internal cylindrical surface 12 of a workpiece 13 by reciprocation of the tool while the abrasive surface thereof is being pressed against the work surface. As in most production honing machines, the tool 11 is carried on the lower end of a spindle 15 journaled in a hollow head is slidable on vertical guide rods 17 (Fig. 1) mounted on the machine frame, parts of which are indicated at lid. The spindle is driven by an electric motor 19 (Fig 3) mounted on the frame and connected to the spindle through suitable'gearing and a spline shaft 26. laising and lowering of the head to enter the collapsed hone into the work bore and withdraw the same therefrom and to reciprocate the expanded hone within the bore may be effected by an hydraulic actuator 21 mounted on the frame and supplied with pressure fluid from a motor driven pump 22 under the control of a reversing valve The honing tool is of a conventional type comprising a series of abrasive sticks or stones 24 angularly spaced around and frictionally held in a body 25 and normally engaging followers of conical cams 26. The latter are fast on a rod 27 which, in this instance, extends upwardly through the tool shank and the spindle 15. When the rod is moved downwardly, the stones are expanded against the bore wall 12, the outward pressure on the stones being continued while the spindle is rotated and reciprocated to enlarge the bore to the desired size. When the rod is moved reversely, the stones are allowed to move inwardly thus collapsing the hone.

While the expander rod 27 may be moved back and forth by various kinds of power actuators, the operator shown herein is of the electric type comprising motors 23 and 29 (Figs. 2 and 3) whose motions are combined by difierential gearing 30 and converted into reciprocatoiy movement of the rod 27. The motors are carried by the tool head 16 and the motor 28 for producing the rapid expansion of the bone is coupled directly to the sun gear 31 of the differential which may as shown he of the planetary type. The speed of the motor 29 is reduced through a worm 33 meshing with teeth on the exterior of the ring gear 32. The spider or intermediate member of the differential carries planet gears 34 and is fast on a shaft 35 coupled through worm gearing 36 to a shaft 37 whose rotary motion is converted to endwise movement of the expander rod 27. While the conversion may be made through a screw mechanism, it is achieved herein by a pinion 38 on the shaft 37 meshing with a rack 39 on an extension of the expander rod 27.

The gear ratios are such that when both of the motors 23 and 29 are operating in a direction to move the rod 27 downwardly, the diameter of the hone at the working faces 40 of the stones 24 will be increased at a comparatively rapid rate, for example .047 of an inch per second. On the other hand, when the motor 29 alone is operating, the diameter of the abrasive surface of hone will be increased at a much slower rate, for example .00019 of an inch per second. This slow rate of expansion by the be varied by suitable means such as a motor 29 may rheostat 29 (Fig. 17) for adjusting a speed controller 29", the speed selected corresponding approximately to the rate of wearing off of the stones when used to hone the particular work material.

Rapid contraction of the bone will occur when the fast motor 2% is operating in the opposite direction. This raises the expanding rod 27 and the cams 26 thereby allowing the stones 24 to collapse. Quick stopping of the ai e-, 31 when the moto .8 s de s d; is effected by energizing the winding of a magnetic friction brake d1 having one element 4 fast on the motor shaft.

Through the circuitry to be described later, the energization of the hydraulic actuator 21 and the motors 28 and 29 is controlled selectively to produce a cycle of operation which includes advance ofthe collapsed hone into the bore of a new workpiece clamped in the machine fixture, rapid expansion of the hone, continued slow expanslon while the hone isbeing reciprocated throughout the length of the bore, collapse of the hone when the bore has attained the desired size and withdr wal of the collapsed hone to permit the finished workpiece to be removed from the niaehine and anpther workpiece substituted. Preferably, the shift from rapid torslow exparr sion, the initiation of the hone collapse, andthe termination of such collapse are controlled; by switches i4, 49 and 45 (H g. 3) acting in conjunctionwith other switches 47 and. &8- which respond to the reciprocatory, movements of the tool head-16;

While the collapse ofthe hone may beinitiated in other ways well known in the art, it is started, in the present instance by a sizing device 50 (Figs. 1 and 3) which feels of the bore wall in: the course of the honing and gives a suitable signal such as cl os nre of theswitch 49 when the bore has been enlargedto the desired size. Herein the SlZlIlg device comprises a sleeve 51 beveled at its lower end 5.2 andhaving an external diameter corresponding to the size of the bore to be sensed. The sleeve isurged downwardlyby a spring 53 to a posit ion determined by engagement. between an externalfiange 5d and an abutment 55 on a bracket 56 which movesf up anddown with the head 16 and permits some degree of lateral floating of the sleeve. 51- transversely of the bore. The. arrangement is suchthat-the sleeve endiSZ reaches the upper end of the borein the latter part of 'each down stroke of the head the sleeve. end-engaging and'centering itself in the end of the borewall and dwelling there during the remainder of thestroke if-the bore is undersize In the next downstroke after the desired bore size has been attained, thesleeveenters the bore under the action of the spring and continues on with the head lfiuntilaan arm 57 on the sleeveengages and actuates the switch 49 which, as shown in Fig; lfis mounted on the machine frame 1 8 i Inaccordance. with the present invention, the actuators for expanding and collapsing the honing toolare controlled in a novel manner such that the rapidexpansion part of each cycletis, irrespective of the wear that has occurred in, the previous cycles, terminated whens the working faces 40;..ofthe stones 2 4-r each' a predetermined diameter fihfidig 10, spaced-only a short distancefrom the bore wall 12 but nevertheless. before any contact occurs between the stonesand the-work. To this end, the rapidexpansion is terminated-by a control element such as theswitch d t whicht is actuated by a device 61 movable back and {01th:.iHJJHiSOn-With thfl hone expander 27 during the V collapse and thepinitial :expansionof 'the hone but joined to the expander.- by-a -coupling 62*wl1ichj permits. the. device to be. held-againshmovement in the final or slow. eap ansipnof the hone.whilesthe'stonesthereof are. in active. .engagement with: the. work-.-

Preferably. the-device, 6.1 ;is associatedwvith a-rotati11g Pa Of h QpQ,,6Xpflnder, inthisinstancethe -shaft-37v Accordingly, the device comprises. an-e1ongated arm- 63 having a hub, journaled onian extension of-the shaft: A radial 1191a w i led in the hub: receives-a shoe-66 (Figs. 4, and 6.) .ur ged against the shaft flbby a spring;

thus ,coacts with. the huhto form- :a. ,coupling-frictionallystress of, I the spring 67.- Thus; when. the arm-- is l un0b- 4 structed it swings back and forth with the shaft and follows the expansion and contraction of the working faces 40 of the honing stones.

The torque transmitted by the coupling 62 is sufficient to actuate the switch 44 which is mounted within the head 16 on a plate 69 (Figs. 2 and 4) with the actuating pin 70 disposed in the plane of oscillation of the arm 6.3 so as to be engaged and pushed inwardly to open the switch 44 when, during counterclockwise turning of the shaft 37, the arm 63. reaches the position shown in Fig. 5. This position is just short of a stop 71 formed. by the rounded end of a screw '72 threading through a block 73 on the plate 69 and" adapted to be advanced and retracted by turning a hand knob 74 which is.- exposed on the exterior of the head 16 and is adapted to be advanced in steps determined by a spring detent '75 (Fig. 2) coacting with notches in the periphery of the knob.

The, stop 7L positively limits the. counterclockwise swinging ofthe arm 63. and, when set for operation in thev intendedmanncr, is spaced; beyond the point of actuation, of the switch 44. by a distance 1: (Figs. 5 and 11.) which corresponds approximately to, the amount of stock to. beremoved from the interior ofthe. bore in an average honing cycle. By cut and try adj'ustmentof the stop 71 v the width of. the. space, a. may be reduced to a. minimum while at the same time insuring interruption of, the rapid! expansion of. thehone just before the stone faces 40, reach the wall, 12 of. a work bore. of minimum diameter.

After, the, armi63, engages the stop 71, as shown inFig. 6 and, the expansion of the; hone continues at the slow cutting rate, the coupling 62 slips andthe shaft 37 continues to turn-Q11 aheadofthe arm 63,-until.the bore has attained the desired size. as determined by the sizing device 50. As a result of, this slippage, therelationship between the arm 6.3andvthe shaft 37 is changed, in each. cycle. by an angle which corresponds substantially to the. amount of wearing off of the stone surfaces during that cycle plus or minus the difference, between the diameter ofwork bore and that of the. bore of, the, previously honed workpiece. The device 61 isthus adjustedautomatically in each cycle and conditionedto terminate. the rapid expansion of the hone close to but short of the bore wall in thenext cycle.

Closure of "the switch 49 in response to the up-to-size signal interrupts the operation ,ofthemotor 29 and energizes the motor 28' for reverse. operation to callapsc the honing tool. Such collap se may, be. etfctedin various ways and with thehone at various diameterswithout appreciably affecting the oyeralllength of the cycle lntthe hQ.W ZLE gS-H 2.. 3, and Y18; the .honeis collapsed fully in each cycle by retracting the expander rodto a limitposition through,thesactuationofrthe switch 45, by an arrn 77 fspaced along theishaft 37.-frorn the. ar1n63 andkeyedor otherwisecmade substantially fast on this shaft. The switch ismouhted on=theplate .69.: (Figs; 2 and 4) for some degree of adjustment to allow for changing the collapsed positionof the,expander rod-127., To ili a o ioninsg 1the...control= imechanisrn after replacement of a set of worn out stones, a screw stop178t (Fig. 3) is- IHOUILtfld OHLthGTPl3tC.691 andtadjustedzto-a positiomto; engage] meg-fined: anm 177'; just after: the :switch 45 is actuatedvduringzclockwise turning oftthe shaftt37 to QllFiPSQr. he; honor.

I ll? observed-1' that: the:.- angular: position of the shaft 37 at any time during active enga-gement'of' tho stonesandtheborewall@IZLis -a measure'ofithe wear which has taken place. Thus, the fully worn out conditionof the stones may'rbedndicated by closure of-fa switch 46 by a roller .onthe end of an arm 80 (Figs;- 2, 3, and 9) which turns with the shaft 37. The switch is fixed-t0, thelr'ead 16 and thearm-is fast on a sleeve-81*(Fig,;2) frictionally coupled througha spring 82, to thoshaft 37Twhich' supports the-sleevee By turning a knob 83"on,thfe outer end. of the sleeve, the position of the shaft at which the switch '5 46 is actuated may be varied to suit difierent kinds or depths of stones that may be used in the tool.

In addition to signalling the worn out condition of the stones 24, closure of the switch 46 may be utilized to effect automatic resetting of the slip arm 63 preparatory to the starting of a new series of honing cycles following replacement of the worn out stones. To this end, an adjustable stop 85 (Fig. 4) is disposed in the plane of oscillation of the arm 63 on the side thereof opposite the stop 71, the stop 85 being normally retracted as shown in full in Fig. 4 but projected into the position shown in phantom in response to closure of the switch 46 and the later energization of a solenoid 86 (Figs. 2 and 4) on the tool head 16. The stop 85 is on the end of a rod 88 connected to the solenoid armature and slidable in a guide tube 87 threaded into a block $9 to provide a stop 9% engageable with a shoulder on the rod. When the solenoid is energized and the stop 85 projected to the limit position shown in full in Figs. 2 and 9 and in phantom in Fig. 4, the arm 63 is engaged and the torque of the friction of the coupling 62 is overcome thus shifting the arm to the new starting position which may be gauged with reference to the position of the fixed arm 77 when the latter is re turned to the collapsed position (Fig. 8). In the ensuing honing cycle, the solenoid 86 is deenergized and the stop 85 retracted out of the way.

Operation An automatic honing cycle utilizing the mechanism above described may be controlled by well known circuitry, a typical form of which is shown in Fig. 17. Assuming that one cycle has been completed, the parts of the mechanism and the control circuits will be conditioned as shown in Figs. 3 and 17 with the spindle drive motor stopped and the pump 22 running. The motors 28 and 29 are deenergized and the winding of the brake 41 is energized. The switch 48 is held open by a earn 112 on a disk 113 which, through a flexible two-way connection 114 with the reciprocable head 16, is rocked back and forth during the advance and retraction of the tool head from the fully withdrawn position shown in Fig. 3.

After a new workpiece has been clamped in the machine fixture, a start switch 114 (Fig. 17) is closed manually to complete a circuit across the power lines and through a normally closed stop switch 11S for energizing a relay R1 which closes its maintaining switch 116 and a switch 117 for energizing a relay R2 through the switch 117 and the start and stop switches. Energization of the relay R2 closes a switch 118 for energizing a solenoid R3 thereby shifting a valve 119 (Fig. 3) to the right so as to direct pressure fluid through a pilot valve 124 and a valve 122 which, by virtue of the deenergization of its solenoid R4, is positioned to direct pressure fluid to the right end of the plunger 121 of the direction control valve 23. The latter is thus conditioned to admit pressure fluid t the head end of the actuator 21 for initiating a downstroke of the tool head 16. In the initial part of this movement, the switch 48 is closed thus completing the holding circuit for the relay R1.

When, in the continued downward movement of the head 16, the collapsed honing tool reaches the lower end of the work bore 12, a lug 126 (Fig. 3) on the disk 113 will engage an arm 127 and turn the latter into engagement with a detent 127 and also cause a cam surface 128 to swing a follower 129 and reverse the posi tion of the pilot valve .128 and therefore the direction valve 23 causing the actuator 21 to start its upstroke. At the same time the follower lever 129 closes the switch 47 to energize a relay R through tie then closed switches 48 and the stop switch 115 Closure of the switch 130 by the relay R5 energizes relays R6 and R7 through then closed switches 117, 116, 48 and 115 Energization of the relay R6 is maintained by its switch 131* and closure by the relay of switches 131 starts the spindle drive motor 19.

on the disk 113 (Fig. 3) engages the arm 127 and moves the cam 128 away from the follower 129. This allows a spring 129 to reverse the position of the pilot valve and thus cause pressure fluid to again be delivered to the head end of the actuator 21. In this way, the hone is reciprocated back and forth in the bore 12.

Closure of the switch 132 by the relay R7 energizes the relay R8 through then closed switches 145, 44, 46 and 151 thereby opening a switch 133 to deenergize and release the brake 41 and closing switches 133 to energize the motor 28 and initiate rapid expansion of the honing tool. At the same time, the relay R8 closes a switch 134 and completes a circuit through then closed switches 152, 138, and 45 thus energizing the relay R9 which is held energized by a switch 153 and closes switches 135 for starting the slow expansion motor 29 which operates at a rate determined by the setting of an adjuster 29 (Fig. 17) of a controller 29 that determines the voltage applied to the motor. The motions of the two motors 28 and 29 are combined by the differential 30 and applied to the shaft 37 to turn the latter counterclockwise so as to lower the push rod 27 and expand the honing stones at the desired rapid rate. In this movement of the shaft 37, the arms 63 and '77 turn in unison with the shaft. This rapid expansion of the hone continues until the surfaces 40 of the stones reach the position 60 shown in phantom in Fig. 10 and disposed close to the bore wall 12. At this point, the arm 63 engages the actuating pin of the then closed switch 44 (Fig. 5) and opens the latter to break the energizing circuit of the relay R8 thus opening the switches 133 to stop the motor 28 and closing the switch 133 to apply the brake 41.

Slow expansion of the hone is continued by the motor 29 alone. The stones first engage the bore wall 12 and by their honing action enlarge the bore wall in the usual way. At some point during this honing action depending on the rate of wearing off of the stones, the arm 63 engages the stop 71 as shown in Fig. 6 after which the coupling 62 starts to slip, the arm remaining against the stop '71 as shown in Fig. 7 as the shaft 37 and the fixed arm 77 continue on in the hone expanding direction until the bore is finished.

In the final part of each downstroke of the hone while engaging the work, the sizing plug 50 comes into feeling engagement with the upper end of the work bore wall 12 where it comes to rest and dwells in a centered position for the remainder of the stroke. The plug is lifted away from the bore during the latter part of each upstroke. Finally, on the downstroke following the enlargement of the bore to the desired size, the plug will enter the bore far enough to close the switch 49. This completes a circuit for energizing a signal lamp 49 (Fig. 17) and a relay R10 to close switches 136, 137 and 139 and open the switches 138 and 151, the relay circuit extending from the relay through the switch 49, a switch 155 then closed by the relay R7, and switches 48 and 114. The switch 136 maintains the energization of the relay and the switch 151 prevents reenergization of the motor 28 in the expansion direction. Opening of the switch 138 results in deenergization of the relay R9 thus stopping the motor 29 to terminate the slow expansion of the hone.

Closure of the switch 139 completes a circuit through the then closed switch 45 for energizing the relay R11 to close its holding switch 160, to open a switch 156 by which the brake 41 is released, and to close switches 140 by which the motor 28 is energized for reverse rotation thereby initiating rapid collapse of the hone. The arms 63 and 77 then in the position shown in Fig. 7 move clockwise with the shaft 37, the arm 63 separating from the stop 71. When the shaft has turned far enough to bring the fixed arm 77 against the actuating pin of the switch 45 (Fig. 8), the latter is opened thus deenergizing the relay R11 to terminate the collapse with the arm 77 disposed substantially against the stop 78.

antenna 6n the nexfi upstrole of the hone fhllowingtlieeupetosize sig-nal or closureof-"the switch 49-,ia*circuit for 'ener gizingthe relay R12 is completed through-the then-closed switches 141 187; 48- and" 114; the" energiz-atiorr of the relay being held by its=-switch-15 7. Glbsure of a switch 142 bythis relay energizesthe solenoid" R4 (Fig. 3") thereby shifting the valvel-zz-to the left so-as to'pr'eventreversal: of the direction control valve 23 when the'lione reachesthe upper limitof itsnormal' working stroke when the; pilot valve 120 is reversed hy engagement" of :1: dog 1 43 with thearm' 1127-1 A switch 1 58* opened by energizationof the relay R-llzbreaks the circuits of the relays R'and Rf?- thus stopping thespind'le'drive motor 19* at thestart of the withdrawingstrokesof the'honez As" a result;, the upstroke of the hone by the" actuator" 21 is continued on beyond the normal honing range thereby fully withdrawing the collapsed lion'e outof the work' bore. Suchwithdrawa-l is termi'natedwhen theswitchlti isopened by the dog 11 2 (Fig. 3"). This-deenergizes' the relay R1 and therefore the rel'ay' R 2 which inturn' de energi'zes the solenoid R3 allowing the valve 119 t'oreturn'to'the starting position'underthe action of -its spring 159 (*Fig. 3'). The openingof theswitcli48and the=re= sulting cleenergization ofthe several relays returns the various 1 switches to I the condition shown inFig: 17;

As-the stonesz t wear away in successive *h'oning'cycles; the arm 80 on the shaft 37- moves farther and'farther' toward tl'ie sWitch-46 and'closes the latter whileopeni'ng the companion switch ifi when the stone's-are fullyworn out; At tliis time, the arm 63 has slipped relativeto'the shaft 37 and'fallen behind thefiXed arm 77as'sliow1rin Fig: 9. Closure of the switch- 46-energizes-a=lamp145' (Fig. 17) to signal the worn out condition of the stones and also -a relay R13 which opens a switch 145 to prevent reenergization of the motor 'ZS'intheeXpanding direction: Therclay- R13 alsoclosesa switch 144 to=condition a circuit for energizing'the solenoid 86 thenext time the" relay Rllh is energized,- in response to the up-to size signal, in. the: next honing cycle to initiate rapid collapse of the hone and termination of that honingcycle: When'the solenoid becomes energized the stop 85 is projected" forwardly to-the position shown inpha-ntom in Fig. 4 so" that during the ensuing rapidcollapseof-thel'ione; thearm d? is-blocked, the coupling 62slipping'duringtl'ie remainder of the hone collapsemotiom In-this'way, the arm 63: isshifted counterclockwise. relative to the shaft 37 and thus returned toanangular'position matching? the fixedarm-T' i as-shownin Fig.- 82 The armfiS' isth'usconditioned' for proper operation. in" the next h'oning cycleafter thewormout' stones have :b'eenreplaced. To .di'sable theexpanding mechanism until the. stoneshave actually beenreplaced; a switch 146' maintains therelay R13 ener gized-until the mechanism is-reset by opening"a manually operable switch l l'i to deencrgize the relay K 13i- Energ-ization 1 of. the relay R 13 also opens aswitch 170 Modification -Figs. 12. :16 und: 18

It will be-apparent that the" expander rod ZT'neednot; in'order toachieve theobjectives-mentioned above; be returned fully to its limitcollapsedposition=in' ea'cli honihg cycle-t Thus,- the rapid collapse part-of each cyclemay be shortened and the-control mechanism=somewhat sim= plified by-utilizing the. arm 63 and its slip coupling 62 10 stop'the rapid motor 28-andterminate the rapidkxpansionpart of the cycle:

Forthis purpose; a normally closed' switchldPismount ed on the plate 69 on the side of the arm' 63*opposite the"- switch.44with it5ractuating pint 162 ldisposediinuthez-planez of oscillation .ofith'e arm and adaptedfonsengagement with: thearm' 63 shortly before. the latter,.in:turning:clockwise (Fig 1 2) during rapid collapse'ofith'e honegc'omesiagainst" an adjustable. step: 163: The.latter islformedibyrthe end; of a screw 164 threading through". a. block 165. onzthe' late 691;

As before; the switch. 45 is arranged to be. closed": in: response to: full collapse. oil the: honing tool as evidenced by return ofi the/shaft 37 to a limit position corresponding to the unworn' condition of: anewset of! honing stones: 24. To eiiectsuchclosure of. thetswitchi45', anoth'eriarm. 1661 is secured to the'shaft 37' in. azpositiontsuch: that at roller thereon engages'the actuatingpin. of theyswitcll 45:

and closes'thelatter when the honehas, by-clockwiser-turningof the shaft. 37; been collapsedfully.

To enable the switch: 161; to. operate in" the intended: manner, the circuit above described is modified; as. shown. in: Fig. 18' by interposing the. switcliin series;with the normally closed switch 45:. and. the switch 139xinttl1e' energizing circuit? of the. relay. RLL by: whichithe: motor ZS 'is'started to initiate rapidcollapse of. the hone. following the up-to-size; signal. Then; to permit of full withdrawal of the: hone out of. the. work. bore, the: switchlfils is disabled: by interposing; a: parallel switch 167; (Fig;

18) in the relay circuit.

In operation, the initial part of each honing cycle is executed in the manner detailed above including entry of the hone, reciprocation thereof in the work bore, starting of the spindle motor, rapid expansion of the hone startingwiththe parts p'ositioned' as shown in'Fi'g; 15', and slowexpansion-of the hone until th'eup-to-size signal is given. Thus the arm 6'3- will have turned in unison with the expander shaft 37 and at the rapid'expansion rate through the angle [1 (Fig. 16) when'the motor 28 was stopped, movedon-during slow expansion first through. an angle 0 against the stop 71 where the arm dwellsas shown in Fig. l'6during-theactual' honing ofthe bore while the shaft 37- is, due to wearing off of the stones, turned through an angle d before the upto-size signal isgiven and the motor 29- stopped; At this time, the relays R1 to R7 and R10 will be energized as described. above.

Closure of'the switch 139 by the relay R10 completes the circuit through the then closed switches 45 and 161K The switches l ltl are thusclosed to start the motor 28 in adirection to turn the shaft 37' clockwise andrapidly collapsethe hone. The arm 63 moves with the shaft until itencounters and actuates the pin 162 to open the switch. 161 thereby deenergizing the relay R11; The motor 28 is-thus stopped'with the arm 63'disposedsub stantially against the stop 163" as-shown in Fig: 15. The remainder of the-cycle including stopping of the spindle motor and full withdrawal of the hone from the work boreiscompleted in the manner detailed above.

Itwill be apparent from the foregoing'that except for variations. in the diameter of the rough bores and different amounts of wear in the honing of successive workpieces, the shaft 37 will swing back and forth through substantially equalanglese in successive cycles, the range of such. oscillation shifting progressively as the stones wean away. Finally, whenthe stones become worn'out, thearm: "v on the shaft will-have moved 'far enough to close: the switch 46, the relay R13 is energized closing" the. switch 167 in parallel with the normally'used rapid collapse switch 161'. Now, when the motor 28; in re-' sponse to the lip-1.0SlZ6 signal, is started: as above described, the rapid collapsing of the hone will not be terminated as before when the arm 63 opensthe switch 161. Instead the arm' comes against the stop 163 and the-coupling dz'slips as the shaft 37 continues to'turnand further collapses the hone; such collapse is continued until thearm'166 opens the switch 45 and stopsthe motor-z The expander rod" is then" fullyretra'cted and the hone fully collapsed preparatory to replacement of" 9. the worn out stones after the head 16 comes to rest following full withdrawal of the hone to the position shown in Fig. 3. As before, the relay R13 remains energized and the expanding control mechanism disabled until the reset button 147 is depressed.

With the circuit modified as shown in Fig. 19, the rapid collapse motion of the hone may be terminated short of the fully collapsed position by utilizing a timer to measure an interval substantially less than that required to turn the shaft 37 through its full range. The timer is a well known time delay relay R14 preferably of the flux decay type having a normally energized winding and a switch 171 which remains closed while the winding is energized and for an accurately measured short interval after the Winding has been deenergized. The relay switch 171 is interposed in the circuits of the relays R9 and R1 1 and the relay winding is in a circuit extending through the switches 45, 171 and a switch 372 which is normally closed but opened by deenergization of the relay R11. For this modification, the switch 161 and the stop 163 for the slipping arm 63 are omitted.

The circuit thus modified operates as before to the point of energization of the relay R11 through the switches 45 and 171 in response to closure of the switch 139 by the relay R10 following the up-to-size signal. This starts the motor 28 to initiate rapid collapse of the hone and at the same time opens a switch 172 for deenergizing the time delay relay R14 which, after the lapse of the desired short interval, opens the switch 171. This deenergizes the relay R11 thus stopping the motor 28 and terminating the rapid collapse of the bone well before the shaft 37 has been returned to its fully collapsed position.

When the stones of the hone are worn out, the full with drawal of the hone and disabling of the expanding is offected as above described by energization of the relay R13 as the switch 46 is closed by the arm 89. The relay R13 closes a switch 169 to establish an independent circuit for the time delay relay R14- through the switches 171 and 45. As a result, operation of the motor 23 is continued beyond the normal collapsed position and until the arm 166 on the shaft 37 opens the switch 45, the motor being stopped with the hone fully collapsed. The relay R13 continues to remain energized and, through its switch 1% (Fig. 17), disables the expanding mechanism until the manually operable switch 147 has been opened after re placement of the Worn out stones.

It will be apparent that the slipping device including the arm 63, the coupling 62, and the stop 71 operates in a novel way to modify the action of the expanding mechanism in accordance with the wearing out of the honing stones so that the rapid expansion part of each cycle is terminated with the stone faces 40 close to but nevertheless out of actual contact with the bore wall. As a result, little time is lost in idle slow expansion of the hone the overall length of the cycle is accordingly reduced.

I claim as my invention:

1. In a honing machine, the combination of, a hone adapted to enlarge a work bore by rotation and reciprocation therein, expanding mechanism including an element movable back and forth to respectively expand and co tract said hone within a work bore, a power actuator selectively operable to move said element and cause expansion of said hone at rapid and slow rates or rapid contraction of the hone, means controlling said actuator to initiate said rapid expansion, a member having a slip friction coupling wih said element and normally moved thereby in unison with said element, a device engageable by said member during expansion of the hone to control said actuator and change the expansion of the hone from said rapid to said slow rate, a stop disposed for engagement with said member at a point beyond the point of engagement whereby to block said member and cause slipping of 10 said coupling during the continued slow expansion of said hone, and mechanism for sensing changes in the diameter of a work bore being enlarged by said bone and controlling said actuator to initiate said rapid contraction of the hone when the bore has attained a predetermined size.

2. In a honing machine, the combination of, a hone adapted to enlarge a work bore by rotation and reciprocation therein, expanding mechanism including an element movable back and forth to respectively expand and contract said hone within a work bore, a power actuator selec tively operable to move said element and expand said hone at rapid and slow rates, means controlling said actuator to initiate said rapid expansion, a member having a slip friction coupling with said element and normally moved thereby in unison with said element, a device engageable by said member during expansion of the hone to control said actuator and change the expansion of the hone from said rapid to said slow rate, a stop disposed for engagement with said member at a point beyond the point of engagement whereby to block said member and cause slipping of said coupling during the continued slow expansion of said hone, and mechanism for sensing changes in the diameter of a work bore being enlarged by said hone and controlling said actuator to interrupt said slow expansion when the bore has attained a predetermined size.

3. In a honing machine, the combination of, a hone adapted to enlarge a work bore by rotation and reciprocation therein, expanding mechanism including an element movable back and forth to respectively expand and con tract said hone within a work bore, a power actuator selectively operable to move said element and expand said hone at rapid and slow rates, means controlling said actuator to initiate said rapid expansion, a member having: a slip coupling with said element and normally moved thereby in unison with said element, a device engageable by said member during expansion of the hone to control said actuator and change the expansion of the hone from said rapid to said slow rate when the abrasive surfaces of said hone are disposed close to but short of contact with the wall of said bore, and a stop positioned for engagement with said member at a point beyond the point of engagement whereby to block said member and cause slipping of said coupling during the continued slow expansion of said hone.

4. In a honing machine, the combination of, a hone adapted to enlarge a work bore by rotation and reciprocation therein, expanding mechanism therefor including a shaft rotatable back and forth to respectively expand and contract said hone Within a work bore, a reversible power actuator selectively operable to turn said element and cause expansion of said hone at rapid and slow rates or rapid contraction of the hone, means controlling said actuator to initiate said rapid expansion, an arm having a slip friction coupling with said shaft and normally movable in unison with said element, a device engageable by said arm during expansion of the hone to control said actuator and change the expansion of the hone from said rapid to said slow rate, and a stop disposed for engagement with said arm at a point beyond the point of engagement whereby to block said arm and cause slipping of said coupling during the continued slow expansion of said hone.

5. In a honing machine, the combination of, a hone adapted to enlarge a work bore by rotation and recipro cation therein, expanding mechanism therefor including a shaft rotatable back and forth to respectively expand and contract said hone within a work bore, a reversible power actuator selectively operable to turn said element and cause expansion of said hone at rapid and slow rates or rapid contraction of the hone, means controlling said actuator to initiate said rapid expansion, an arm having a slip friction coupling with said shaft and normally movable in unison with said element, a device engageable by said arm during expansion of the hone to control said actuator and change the expansion of the hone from; said, rapid .to. said-slow. rate, ,astop .disposedzfor en+ gagement with saidv arm. at. KIBQlHlIIbQ YOBdT the point of engagement: whereby; to block said arm and cause. slipping of saidcoupl-ingduring: the. continued slow expansionof said hone, means:v controlling said actuator to interrupt saidislow expansion and initiate rapid contraction of the. hone, a-secon diarm fast-on saidishaft, and a.

second device. engageablev by said second arm. andv operable to interrupt saidirapid contractionwhen saidzhone,

has been ifully collapsedi 6. Ina-honingmachine, the. combination of, a honeand-cause expansionofsaidhone at. rapid and slew rates.

or rapid contraction-bf. the hone, means-controllingsaid actuator to initiate said: rapid expansion, anarm having.

a slip friction couplingwithasaidshaft and normally movable in unison with saidelement, .a device engageable by said arm during expansion of thehoneto control said actuator and change the, expansion of; the hone from said rapid to said slow rate,,a stop. disposed forv engagement with said arm at. apoint. beyond the. point. ofv

engagement whereby to blocksaid-arm .andcause slipping of said. couplingnduring. the continued slow expansion of said hone, means controlling said actuator. to, interrupt said slow expansionandinitiate. rapid-contraction of the hone, a second arm fast. on said shaft,.a.second. device,

engageable by said. second arm andoperable to,v interrupt said rapid contraction when. said hone has been fully \gollapsed, a second stop disposed on the, side of saidfirst arm opposite. said first stop. for engagementwith the first arm, and means for shifting said second stop intoa position to engage said first arm and slip. thelatter. relative to. said shaft during the rapid collapse. of said hone.

7. In a honingmachine the combination of, a hone adapted to enlarge a work bore by rotation and reciprocation therein, expanding mechanismtor saidhone including an element movable back and-forth to respectively expand and contract saidhone within. a Work. bore. and through a range between fully Worn and fully collapsed positions, a power actuator selectively operable. to move said element and produce. expansionof said hone at, rapid and slow rates or. rapid contractionof the hone, means controlling saidactuator. to initiatesaid rapid'expansion, aimember having aslip fri-ctioncoupling with, said element and normally moved thereby in unison with said element, a device. engageable.v by saidmember during expansionof the hone to controlisaidactuator and change the expansion of the honefrom. said rapid. to said slow rate, an adjustable. stop disposed adjacent but spaced beyond said device for. blockingv engagement with said element, means automatically controlling. said. actuator 12 to initiate said rapidicollapseiof thedlone andiatseconds similar, device engageable, with,said member; during; said. rapid: collapse to terminate. the. operation of said actuator; before said=element reaches saidfully,collapscdposition.

8. In a honing machine, the combination of, a.-hone. adapted to enlarge a work bore by rotation and reciprocation therein, expanding mechanism for said hone including an element movable back. and forth to respectively expand and contractsaid'hone within awork bore and through a range betweenfully Worn andlfully, col lapsed positions, a power actuator selectively'operable" to move said element and produce expansion: ofsaid: bone at rapid'andslowrates or rapidcontraction: ofthe hone, means controlling said actuator to' initiate said rapid expansion, 2. member having a slip friction'coupling with said element and normally-moved therebyirruni son with said element, a device-engageableby said mem-L her during expansion of the-honeto control said acttn ator and change the expansion of" the hone from-said;-rapidto said slow rate, an adjustable-stop disposedadjacentr but spaced beyond said-device for bloc-kingengagemenb with said element, means automatically controlling' said actuator toinitiate said rapid-collapse-ofthehone, asecond similar device engageable with said-membenduring said rapid collapse to-termina-te the'operationofsaid actuator before said element reaches-said=fully-collapscd" position, and mechanism responsive-to-movement of'said shaft to said fully worn position=and*operable to disable said seconddevice during said rapid collapse andcon tinue such collapse until said element reaches saidfifully' collapsed position.

9. In a honing machine, the combination of, a hone adapted to enlarge a work bore bytrotation and recipro'-- cationtherein, expanding mechanism for said'honein cluding an element movable back andforth to respectively expand and contract said hone within a work bore and through a range between fully'worn-and fully'ool lapsed positions, a power actuator selectively operable-- to move said element and produce expansion of'rsaid hone at rapid and slow rates or rapid'contraction of' the hone, means controlling said actuaton to initiate said" rapid expansion, a member having aslip friction coupling with said element and normally moved thereby in 'unison with said element, a device engageable by said: member during expansion of the hone to control saidxactuatorsand change the expansion of. the hone from said rapid to said: slow rate, an adjustable stopadisposed.adjacentibut spacedbeyond said device for blocking engagementwitli; said: element, means automatically. controlling: said actuatontot: initiate said rapid collapsed-f the hone;.and-:timi11g mech} anism activated. as an incident to.starting: of saidrapidi collapse and operable to. stop. saidzactuator beforesaid? element reaches said fully. collapsed position;

No references cited.-

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