US2795089A - Honing machine - Google Patents

Description

June 11,A 1957 E. Y. sEBoRG 2,795,089

HONING MACHINE Filed Aug. l. 1955 3 Sheets-Sheet l ccwnea W /Shag June 11, 1957 E. Y. sEBoRG 2,795,089

HONING MACHINE Filed Aug. l, 1955 5 Sheets-Sheet 2 E. Y. SEBORG HONING MACHINE June 11, 1957 5 Sheets-Sheet 5 Filed Aug. l, 1955 n m, M/ mlm .QIJ l. .d .ITQIII S j Lf 4| f Y 1 1 5 /f i MV. F 5 M /TL w V| L X f f fl VR. Y .L v 5\v L rr. uw f 4% @n m 5 V n s A C P. +I i M". A. m m M u f a L L M. l w F P LIL l. O *pm Y United States Patent O HONING MACHINE Earnest Y. Seborg, Rockford, Ill., assigner to Barnes Drill Co., Rockford, Ill., a corporation of Illinois Application August 1, 1955, Serial No. 525,667

with the bore wall whereby to limit thepressure transmitting capacity of the connection.

One object of the invention is to providenovel hone expanding mechanism of the above character in which the full pressure transmitting capacity of the connection is established in response to contact of the hone with the bore wall and in timed relation to termination of the high speed expansion so as to reduce the time required for the transition from high to low speed expansion while avoiding damage to the hone.

Another object is to establish the full pressure trans'- mitting capacity of the' connection by clamping the relatively movable parts of the latter together as an incident to contact ofthe hone and thework. i

A more detailed object is to utilize the relative movement of the pressure limiting parts themselves to produce a signal for changing from rapid to slow expansion and for timing of the clamping of the parts against further relative movement.

Other objects and advantages of the invention will become apparent from the followingl detailed description taken in connection with the accompanying drawings, in

which Figure 1 is a fragmentary elevational View of the head and tool of a honing machine embodying the novelv features of the present invention.

Figure 2 is a fragmentary sectional view taken' along the line 2-2'of Fig. l.

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

Fig. 4 is a fragmentary sectional view taken along the lineV 4-4 of Fig. 3.

Fig. 5 is a schematic view of the hone expander drive mechanism and an electric circuit diagram.

While the invention is applicable' to all types of honing machines, itis especially adapted for high production machines and: is shownv for purposes of illustration incorporated in a so-called vertical machine in which the honing tool 10 is carried by the lower end of a jointed hollow shank 11 coupled to a spindle 12'. The latter' is journaledl in a hollow head 13 reciprocable vertically on stationary guides 9 on the machine frame" (not shown) and isV rotated by an electric motor 14 mounted on the frame and driving a splined shaft 15 geared to the spindle. To raise andl lower the head 13 for entry and removal of the collapsed hone into and out of the bore 16 of a workpiece 17 and for reciprocation of the'expanded honeV within the bore, a hydraulic actuator 18 mounted on the frame is connected to the head and is suppliedA with pressure'- fluid' in' a manner' well known in the art.

The honing tool'10 is of thew type comprising a-series rifice of stones 19 spaced angularly around and shiftable radially relative to the body 20 and normally held in inner collapsed positions by garter springs 21. Outward expansion of the stones is eected in this instance by downward axial shifting of a rod 23 which extends upwardly through the hollow tool shank 11 and spindle 12 and, at its lower end, carries conicaly cams 22 acting on the inner sides of the stones, the latter shifting inwardly under the action of the garter springs during upward shifting of the rod and the cams.

Motion for shifting the expander rod 23fto expand the hone 10 is derived from power operated mechanism 24 (Figs. 1 and 4) which produces motion at high and low speeds respectively in response to the energization of two electromagneticwindings 25 and 26. in the present instance, the windings are parts of two electric motors 27 and 28 mounted on the head 13 and coupled to the terminal members 29 and 30 of a planetary type differential gearing (Fig. 5). The shaft of one motor 2'7 carries the sun gear 29 of the diierential, this gear meshing with angularly spaced planet gears 31 whose shafts are journaled on the spider or intermediatemember 32 of the dilerential. The ring gear3) meshes with the planet gears 31 and, on its outer periphery, is toothed to constitute a worm wheel meshing with a worm 33 which is connected to the shaft of thev other motor 28 through anotherl worm 34 and worm wheel 35. A shaft 36 jour naled in the head 13 (Fig. 2) and secured at one end to the spider 32 constitutes the output member of the drive mechanism 2'4.

, The motion of the output shaft 36 of the expander drive mechanism 24 is converted to reciprocatory motion and is -transmitted to the expander rod 23 by a connection 37. Herein, the latter comprises a worm 38 rotatable with the output shaft 36 and meshing with a worm wheel 39 journaled on the'head for rotation about a vertical axis. The wheel is threaded internally to form a nut for a screw 40 on a vertical shaft 41 slidable endwise along the axis of the expander rod but held against turning relative to the head. At its lower end, the screw shaft bears against a slidahle plug 42 supporting the upper end of the expander rod 23 in a thrust bearing y43 (Fig. 2).

It will he' apparent that the rotary motions. of the motors Z7 and 2S ,are combined by the differentialy to produce rotary motion of the output shaft 36, and, after further speed reduction by the worm gearing 38, 39 and the nut and screw 39, 40, are converted to axial shifting motion of the expander rod 23.A The gear ratios of the parts of the drive mechanism 24 and the connection 37 are such that, when the windings 2S and 26 of both motors are energized for operation of the latter in a direction to move the rod downwardly, the hone 10 expands at a comparatively rapid rate such as .047 of an inch per second. On the other hand, when only the winding 26 is energized for operation of the motor 28 alone and the sun gear 2% is held against rotation, the rate of expansion is much slower, for example, .00019 of an inch per second, this rate corresponding. approximately to the rate of wearing off of one type of honing stone and work material. The sun gear 29 preferably is held^ against rotation each time the motor 27 is. deenergzed by a suitable brake 44 which may be of the electromagnetic friction type having a winding 45 (-Fig. 5) and operable, when the winding is energized to' apply a retarding torque to the motor shaft, the Winding being energized anddeenergized respectively when the motor is deenergzed and: energized. Variation of the rate of slow expansion-maybe obtained by manually adjusting a potentiometer 46 forming'a part of a speed regu lator 47' (Fig. 5) whichv controlsl energization of the slow motor 28.

To enable therapid expansion parts to come toV a stop without applying further pressure to the stones 19 after the latter contact the bore wall 16, the connection 37 includes a device having parts normally held against relative movement but shiftable relative to eachlother in response to the build-up of pressure inthe connection following engagement of the stones with the bore wall, the device thus limiting the torque transmitting capacity of the connection. In the present instance, the torque limiting device comprises the output shaft 36 of the drive mechanism 24 and the worm 38 which is splined on this shaft. During rapid expansion of thestones, the worm is urged axially of the output shaft and against a stop 48 as shown in Fig. 3 on the head 13 by a spring 49 acting between the head and a lever 50 fulcrumed intermediate its ends on the head. The lever is connected to the worm 38 by trunnious 51 formed on a yoke 52 at one end of the lever and projecting into a peripheral groove of a collar ,53 journaled on but fixed against movement axially of the worm. The spring 49 yields for shifting of the worm away from the stop when the pressure builds up in the connection 37 but before such pressure becomes sufficient to crush `the stones.

Means is provided to sense initial contact of the stones 19 with the bore wall 16 during rapid expansion of the stones. In the present instance, such contact is detected as a build-up of torque in the connection 37 between the drive mechanism 24 and the hone expander 23. To simplify the construction, the initial relative shifting of the parts of the torque limiting device 36, 38 in response to the pressure build-up after contact of the stones and the bore wall preferably is utiilzed to actuate a switch LS6 (Figs. 2 and 5) which thus provides a signal of such contact. In this instance, the switch is housed within a casing 54 mounted on a partition 55 in the head 13 for movement of the switch actuator 56 by a plunger 57 slidably mounted on the partition and yieldably urged byla spring 58 away from the actuator and against a cam surface59 on a sleeve 60 rigid with the worm 38. The switch LS6 is located in circuits which control energization of the rapid expansion motor 27 and operate, when the switchis actu,- ated upon contact of the stones with the bore wall 16, to deenergize the motor and energize the brake winding 45 in a manner to be described later to bring the rapid expansion parts to a quick stop. Y

Due to their inertia, the rapid expansion parts require a linitetime interval to come to a stop, the worm 38 contnuing to shift along the output shaft 36 against the action of the spring 49 to limit the torque transmitting capacity of the connection 37 during such stopping. To allow time for the stopping while avoiding any loss of time for the transition from rapid expansion of the stones to slow expansion for feeding of the same into the work 167 the presentinvention contemplates establishment of the full pressure transmitting capacity of the connection 37 in timed relation to contact of the stones with the bore wall and as soon as possible after the rapid expansion parts have come to a stop. This is accomplished by the locking or clamping of parts 36 and 38 of the pressure limiting device rigidly together in response to contact of the stones and the work and at the end of a predetermined time interval which expires long enough after such contact to insure that the rapid expansion parts have stopped.

Clamping of the worm 38 against further axial shifting along the output shaft 36 and away from the stop 48 after the rapid expansionparts have come to a stop is effected by energization of an electromagnetic winding 61. The latter, in this instance, is part of an electromagnetic friction brake 62 (Fig. 4) `having a magnet with an annular core 63 of magnetic materialiof U--shaped cross section enclosing the winding and stationarily mounted on the head 13. Annular axially facing `pole faces 64 on. the core are spanned by and adapted for axial gripping engagement with a fiat magnetic armature disk 65 which `is fast on a shaft 66 journaled in the head for rotation about the axis of the core. The retarding torque of the brake produced by energization of the winding is transmitted to the worm 38 by a gear 67 fast on the brake shaft 66 and a gear segment 68 meshing with the gear and formed on the end of the lever 50 remote from the yoke S2 which is connected to the worm to shift axially therewith as described above.

The time interval for stopping of the rapid expansion parts and for energization of the worm brake 62 is dctermined by a timer TD (Fig. 5) whose operation is started in response to actuation of the Contact sensing switch L86 upon initial shifting of the worm 38 away from its stop 48. Herein, where the contact sensing switch is normally closed and is opened upon contact of the stones 19 and the work 16, the timer TD may comprise a relay which is connected in series with the sensing switch across supply lines L1, L2 (Fig. 5) and is of the type having a delayed drop out. Such delay may be effected, for example, by a dash pot 69 of which the piston 7i) is connected to the movable one of the Contact elcments TD-l of the relay TD with the rate of movement of the piston varied by adjustment of a valve 72. To apply the worm brake 62 at the end of the interval dctermined by the timer relay TD, an energizing circuit for ythe brake includes normally closed contacts TD-I or the relay connected in series with the brake winding 61 across the output terminals of a rectifier 73 whose input terminals are connected to the supply lines Lil and L2.

Operation Energization and deenergization of the windings 2S and 26 of the motors 27 and 28 for expanding and contracting the hone 10 occur at proper times in an automatic cycle of the honing machine governed by mechanism well known in the art and including certain of the control circuits of Fig. 5. Assuming that a cycle has been completed, the circuits are conditioned as shown in Fig. 5 with the spindle drive motor 14, the hone expansion motors 27 and 28, and the worm brake winding 61 deenergized and with the rapid expansion brake winding 45 energized through a circuit extending between the output terminals of the rectifier 73 and through normally closed contacts MF-l and MR-l of two relays MF and MR controlling energization of the rapid expansion motor 27 for rotation in oppositedirections.

After a new workpiece has been clamped in a suitable fixture (not shown) on the machine, a start switch 74 is closed manually to complete a circuit across the A. C. power lines Lil and L2 for energizing a relay R1 through a normally closed stop switch 75. The resulting closure of contacts Rl-l completes a circuit for energizing the relay R2 through contacts LS41 of a switch L84 (Figs. 2 and 5) positioned on the head for actuation by a roller 76 carried by a rack bar 77 meshing with a pinion 78. The latter meshes with rack teeth 79 formed on an extension of the screw shaft 41, endwise motion of the expander rod 23 `to its upper limit position thus being utilized to close contacts LS-nl when the hone is fully collapsed and to open the contacts when the rod starts its downward movement to expand the hone.

Energization of the relay R2 closes its contacts R2-1 thereby completing a circuit across supply lines L3 and L4 for energizing a solenoid 80 to supply pressure fluid to the hydraulic actuator 18 fand thereby initiate downward movement of the head 13. In the tirst part of this movement, a switch LS1 is closed to complete a holding circuit for the relay R1 through contacts R1--2 thereof and the stop switch 75, and a holding circuit for the relay R2 through the then closed contacts Ril-3 and R2-2. Operation of the switch LS1 and of a switch LS2 referred to below is effected in response to movements of the head 13 in a manner well known in the art.

When, in the continued downward movement of the head 13, the honing tool 10 reaches the lower end of the work bore 1,6, Athe switch LSZ is closed, this switch remaining closed while" theftool reciprocates within the bore but opening in response'to withdrawal. of the tool from'the bore. Closure of the switch LS2 completes a circuit throughA a relay R4- for closure of its contacts R4--1 to energize the spindle motor 14, contacts R4-2 in a sizing circuit, and contacts R43r in series with the now closed contact sensing switch LS6 to energize the timing relay TD and the relay MF. Contacts R4-5 in. series with the worm brake winding 61 are closed and contacts R4'-4 are opened in series with the relay MR controlling rotation of the rapid: expansion motor 27 in adirection towithdraw the expander rody 23'. The relay then'. opens contacts MF-l for deenergization of the brake winding 45, closes contacts MF--Z' thereof for energization of.' the rapid expansion motor 27, and closes contacts MF4l in series with a relay R3 for the slow expansion. motor 28;

In the initiall part ofthe ensuing downward shift of the expander rod 23, the contacts LS4f-1 of the switch LS4`` are. opened by withdrawal of the'roller 76 as shown in Fig. 2 andl companion contacts LS4-2 are closed, the latter completing the circuit through the contacts MF-3 for energization of the relay R3. The latter pulls in to close contacts R3--1 in a holding circuit around the contacts MF'-3 and contacts R3-2 for connecting the slow expansion motor 28 to the speed regulator 47 thereby energizing thisl motor.

With both expansion motors 27 and 28' operating, the output shaft` 36 rotatesy at its fast speed' to shift the expander 23- downwardly and expand the honing tool tothe full" size of the work boreV 16 in a small fraction of'a second. As soon as the rapidly expanding stones 19 come against the work', the pressure thereon and the torque in the driving connection 37 build up rarpidl'y. When such torque attains a value suicient to overcome the spring 49, the worm 38' and its sleeve 60 shift axially away from the stop 48 and, in their initial movement, the cam 59 shifts the plunger 58-y outwardly to open the switch LS6 and thereby signal contact of the stones with`the work. The relay MF thus isdeenergized to open the contacts MF2 in the circuit for the rapid expansion motor 27 and to close the contacts MF-l for energizing theY brake winding 45. thereby bringing the rapidA expansion parts to a' quick stop. Although the contacts' M13-3 are opened at this time, energization ofy i the' slow expansion motor 28. continues by virtue of the holding circuit for the relay R3 through the contacts R13-f1 and LS4-2. K s

When the contact ysensing switch LS6 opens, the timing relay. TD is deenergized to initiate the time interval before the worm brake winding` 61 is deenergized. During this interval .while the rapid expansion parts are. stopping, the worm 38 continues to shift yawayfrom the stop 48 and the brake armature 65 is turned. relative to the core 63 through the yoke 52, the lever 50, and the. gear 67. At. the end of the interval. which: is. determined by the setting of the dash pot valve 72 and. which is just long enough tov insure safely that. the rapid expansion parts have stopped, the timing relay contacts TDLI. close to complete thecircuit` through thewormfbrake winding 61 thereby. energizing the latter to lock thev worm against further movementvv relative to the. output shaft 36. The full torque transmitting capacity ofv the connection 37 thus.r is established. and, the slow expansion motor'still being energized, the stones 19 Vare expandedinto the work at v'their slow feed 'irate while the hone. is recprocated back and; forth throughthe work bore.

Termination ofA the honing operation -by 7 contractionof the stones v1'9"and withdrawal ofthe tool" 10 axially from the bore -16`when the latter reaches vthe. desired'diameter may be etectedin various. ways asA by a suitable gaging device (not'shown) adapted to measure/the |bore'and close a switch LS5l when the bore is of thefinished size. Upon kclosure of: the .sizing switchLS5 "and, aswitchf LS3\`V which isfclosed 'at the. endof each downstrokeof the head 13`y afvcircuit for energizing a' relay R6 is completed through the stop switch 75 andthe head actuated. switch LS1; The. energization vof thisrelay is maintainedv through sealing contacts R6-1 and results in closure of contacts R15-2' for energizing a. withdraw relay R5 to close contacts R5-1 thereof to establishk circuits controlling the pressure uid system and effect withdrawal of the tool 10 from the bore 16. Also, contacts R6-3 and R6-5 arev opened in the circuitst-o the' forward motor relay MF and to the slow expansion relay R3 while contacts R6-4 close to energize the relay MR. Contacts MR-1 of the latter then are opened to deenergize the motor brake winding 45 and contacts MR-Z complete circuits to energize the motor 27 rotation in a reverse direction to retract the expander screw 40 thereby permitting the garter springs 21. to contract the stones 19 and retract the expander rod23. Other contacts R6-6 open in the circuit for the worm brake winding 61 todeenergize the latter. Then, in the initial reverse turning of the worm with the output shaft 36-the spring `49 shifts' the sleeve 60 to permit thev contact switch LS6 to close after which therwormagain abuts itsstop 4-8.

As soon: as the expander screw 40 reaches its fully retracted position, the roller 76 actuatesV the switch L84 to close theV contacts LS4--1I and open contacts LS4-2 thereby interrupting thel circuit to the contact relay MR for deenergization ofthe fast motor 27. Normally, collapse of the hone'by. the reverse 'action of the motor 27 is completed substantially instantaneously and before the hone. passes yout of. the bore. When the hone is withdrawn from the latter under the control of the withdraw relay R5', the switch L82 opens tol deenergize the relay R42 resulting in de'energization of the spindle motor and the relay R6. The withdraw relay R5 and the relays R1 andl R2' remainv energized. until. the head 13 has been raisedto its fully retracted position'as indicated by opening of the switch LS1; The' head then comes to rest and they circuits are conditioned' for the start of the next cycle which may be initiated by again closing the manual switch 74 after anew workpiece has been'placed in the machine xture.

Itv willk be apparent from the foregoing that the provision of aclamp for'locking the parts 36 and 38 of the pressure limiting device against relative` shifting makes it possible to protect the stones 19 against' crushing pressuresl durin-g high speed expansion with the clamp deenergized, -and yet, to attain rapid transition trom high to. low speed expansion upon energization of the clamp. By utilizing the relative shift of the pressure limiting parts 36 and 38 t-o indicate contact of the stones with the bore wall, these parts not only protect the stones against crushing pressures but also perform the additional y functions' of controlling' termination of the rapid expan sion'. and starting the timing of thev interval before the parts are .locked to establish the full. torque transmitting capacityoff the connection 37, the timer TD providing a simple. and'v reliable means for controlling and effecting the locking quickly 'after the rapid expansion parts have stopped;

I claim as my invention: v1. In a machine for honing a work bore, the combination of, a honeY having an expander, power operated mechanism for produc-ing motion at high and low speeds reavancee honefmeans operable during such expansion to sense axial shifting of said wormy and elect deenergization of said high speed winding while maintaining said low speed winding energized, a timer started in `operation in responseto the initial shifting of said worm away from said position and operable to measure an interval substantially equal to that required for terminating the high speedexpansion of said hone, a brake coupled t-o said worm and operable when activated to block the worm against `shifting axially `in a direction away from said position, and means controlled iby said timer and operable upon the expiration of said interval to activate said brake whereby to establish the full torque transmitting capacity of said connection during the continued low speed expansion of said hone.

2. In a machine for honing a work bore, the combination of, a hone `having an expanderfpower operated mechanism for producing motion at high and low speeds respectively in response to the energization of two electromagnetic windings, a connection transmitting thc high and low speed motions of said mechanism to said expander including a device having two parts normally held against relative movement `but movable relative to each other in response to the engagement of the hone with a work bore during rapid expansionof the hone whereby to limit the hone expanding pressure transmitting capacity of said connection, means for energiz ing said mechanism to initiate rapid expansion of said hone, means operable during such expansion to sense relative movement between said parts and eiect deenergization of said high `speed winding while maintaining said low speed winding energized, a timer started in operation in response to the initial relative movement between said parts `and, operable toy measure an interval substantially equal to that required for terminating the high speed expansion of said hone, and means controlled by said timer and operable upon the expiration of said interval to clamp said parts together against further relative movement whereby to establish the full pressure transmitting capacity of said connection during the continued low speed expansion of said hone. y

3. in a machine for Vhoning a work bore, the combination of, a hone having an expander, power operated mechanism for producing motion at high and low speeds respectively in response to the energization of two electromagnetic windings, a connection transmitting the high and low speed motions of said mechanism lto said expander including a device having two parts normally held against relative movement but movable relative to each other in response to the build up of pressure following engagement of the hone-with a work bore during rapid expansion of the hone whereby to limit the hone `expanding pressure transmitting capacity of said connection, means for energizing said mechanism to initiate rapid expansion of said hone, a sensing device operable during such expansion to detect` said engagement of said hone and bore Wall, means operable in response to said sensing device to effect deenergization of said high speed winding while maintaining said low speed winding energized, a timer started in operation in response to detection of said engagement by said sensing device and operable to measure an interval substantially equal to that required for terminating the high speed expansion of said hone, means including an electromagnet and operable when activated to clamp said parts together against further relative movement, and means controlled by said timer` and operable to activate said clamping means at the expiration of said interval whereby to establish the full torque transmitting capacity of said connection during the continued low speed expansion of said hone.

4. In a machine for honing a work bore, the combination of, a hone having an expander, power operated mechanism for producing motion at high and low speeds respectively in response to the energization of two electromagnetic windings, a connection transmitting the high and low speed motions of said mechanism to said expander including a device having two parts normally held againstvrelative movement but movable relative to each other in response to the build up of pressure following engagement of the hone with a work bore during rapid expansion of the hone whereby to limit the expanding pressure transmitting capacity of said connection, means for energizing said mechanism to initiate rapid expansion of said hone, a sensing device operable during such expansion to detect said engagement of the hone and the work bore, means operable in response to said sensing device to effect deenergization of said high speed winding while maintaining said low speed winding energized, a timer started in operation in response to detection of said engagement by said sensing device and operable to measure an interval substantially equal to that required for terminating the high speed expansion of said hone, and means controlled by said timer and operable upon the expiration of said interval to clamp said parts together against further relative movement whereby to establish the full pressure transmitting capacity of said connection during thc continued low speed expansion of said hone.

5. In a honing machine, the combination of, an expansible and collapsible hone having stones and an expander, a power actuatable mechanism for producing motion at high and low speeds respectively, a connection transmitting the high and low speed motions of said mechanism to said expander including a device having parts normally held against relative movement but shiftable relative to each other under the resistance offered by the wall of a work bore when the wall is engaged by said stones, means operable when activated to lock said parts of said device together to transmit sufficient pressure to said stones to feed the same into said bore wall, means for controlling said mechanism to initiate expansion of said hone at said high speed, means for sensing contact of said stones with the wall of a work bore when said hone is expanding at said high speed, a timer responsive to said sensing means and started as an incident to contact of said stones with a bore wall,` means controlled by said sensing means and operable to change said mechanism from said high speed to said low speed operation, and means controlled by said timer and operable to activate said locking means after said change from high speed to low speed operation.

6. In a honing machine, the combination of, an expansible and collapsible hone having stones and an expander, a power actuatable mechanism for producing motion at high and low speeds respectively, a connection transmitting the high and low speed motions of said mechanism to said expander.- including a device having parts normally held against relative movement but shift-` able relative to each other under the resistance offered by the wall of a work bore when the wall is engaged by said stones, means operable when activated to lock said parts of said device together to transmit suicient pressure to said stones to feed the same into said bore wall, means for controlling said mechanism to initiate expansion of said hone at said high speed, means for sensing contact of said stones with the wall of a work bore when said hone is expanding at said high speed, means controlled by said sensing means and operable to change said mechanism from said high speed to said low speed operation in response to contact of said stones with said wall, and mechanism controlling said locking means in response to said sensing means and operable to activate the locking means in timed relation to and after said change from high speed to low speed operation.

References Cited in the le of this patent UNITED STATES PATENTS 2,377,310 Caldwell June 5, 1945

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