US2870577A - Honing machine with plug sizing - Google Patents

Description

Jan. 27, 1959 E. Y. sEBoRG HoNING MACHINE WITH PLUG sIzING original Filed Jan. 2e, 195e 2,870,577 HONING MACHINE WITH PLUG SIZING Earnest Y. Seborg, Rockford, Ill., assignorto Barnes Drill Co., Rockford, lil., a corporation of Illinois Continuation of application Serial No. 561,483, January 26, 1956. r.This application October 30, 1957, Serial No. 693,390

3 Claims. (Cl. 51-34) This invention relates to honing machines equipped with a plug for mechanically feeling of the work bore automatically and periodically during reciprocation of the honing tool and eventually entering the bore when the latter has been enlarged to the desired size. The invention is more particularly concerned with gaging devices in which the sizing plug is a sleeve surrounding the tool spindle and carried into and out of feeling engagement with the work in the down and ,up strokes of the honing head.

The general object is to derive the up-to-size signal from the sizing plug in a novel manner which, as compared to prior constructions, provides for consistently greater accuracy in measuring the sizes of the bores of successive work pieces being honed and this irrespective of the size of the bore being honed.

A more detailed object is to sense the entry of the sizing plug into the uptosize bore without imposing on the plug any sidewise or other variable forces tending to tilt the plug or otherwise interfere with the freedom of its entry and the uniformity' of such entry in successive machine cycles.

The invention also resides in the novel arrangement of the gage plug and the size sensing device to achieve the foregoing objects.

Other objects and advantages of the invention will become lapparent from the following detailed description taken in connection with the accompanying drawings, in which Figure 1 is a fragmentary view of the principal elements of a simple homng machine incorporating the improved sizing device.

Figs. 2 and 3 are enlarged fragmentary views of a part of Fig. 1 showing the sizing device in longitudinal section land in different positions.

ln the simplied honing machine shown in the drawings ,for purposes of illustration, the honing tool is on the end of an elongated rigid spindle 11 which, after entry of the hone into the bore 12 of a workpiece 13 as shown in Fig. 2, is reciprocated back and forth by suitable means such as a power rotated crank 14. Hereinthe crank motion is transmitted through a connecting rod 15 to a nonrotatable rod 16 coupled through a bearing 17 to the upper end of the spindle which is formed by a sleeve 18. The latter is splined into an internally toothed sleeve 19 journaled on the machine-frame 20 and carrying a gear 21 through which the spindle is rotated from a suitable power source.

The hone comprises a series of abrasive sticks or stones 21 frictionally held in slots angularly spaced around a hollow body 22 at the lower end of the hone. The usual rod 23 extends down through the spindle to the conical cam by which the stones are expanded or allowed to collapse. A head 24 on the upper end of the rod 23 carries a pin 25 which rides in a helical groove in a sleeve 26 splined into a sleeve 27 journaled on the machine frame and adapted to be turned l by endwise movement of a rack bar 28 meshing with a gear on the sleeve. Thus, in response to opposite movements of the rack bar, the rod 23 is lowered and raised to respectively expand and contract the hone.

2,870,577 Patented Jan. 27, 1959 ICC In the present instance, entry "of the honel into the lwork bore preparatoryto actual honing is etected by moving the work xture vertically. The workpiece is thus carried to the operating position shown in phantom in Fig. 1.

v ln the present instance, the improved sizing device in.l dicated generally at 30 is mounted on the spindle 11 above the hone 10 and carried into engagement with the upper end 31 of the work bore in the final part o f Yeachv advancing stroke and retracted during the reverse stroke. For this purpose, the device comprises a plug in the form of a thin walled sleeve 32 of comparatively light weight i loosely surrounding the spindle 11 above the hone 1l!l and having angularly'spaced hardened segments 33 se, cured as by brazing to the shouldered lower end of the sleeve and externally sized to enter the work bore as shown in Fig. 3 when the latter has been enlarged precisely to the desired size. The extreme ends of the segmentsv are chamfered as indicated at 34 to define a beveled surface for causing the plug to center itself in the bore as the segments come against the end 31 of an Y under size bore as shown in Fig. 2. Such automatic centering is permitted by the provision of a narrow radial clearance 35, usually about .008 of an inch, between the interior of the sleeve 32 and the exteriory of the spindle.

Downward movement of the plug along the spindle is limited by engagement of the plug end 36 with a stop formed by the upper end 37 of the hone body 22. The plug is urged downwardly against the stop by a light force only sufcient to insure immediate entry ofthe plug end f' 34 into the bore when the latter cornes up to size. Herein, the force is derived from a loosely coiled spring38 encircling the spindle and bearing at one end against a collar 39 on the spindle and at the other end against a. right angular flange 40 which may be integral with'the upper end of the sleeve 32. With the spring thus constructed and arranged, the line of its action coincides with the spindle axis thus avoiding a tendency for the springl to tip the plug after it has come into feeling engagement with the bore end and become centered therein.

In each honing cycle, the sizing plug remains against the stop 37 and moves downwardly with the hone until its beveled end comes against the end 31 of the bore' wall in the nal part of the down stroke. The motion of the plug is arrested and, under the force of the spring and the light impact ofthe engagement, the wall edge 31 acts on the beveled surface 34 to interrupt further turning of the plug and also to cam the plug laterally as permitted by the clearance 35. Inthis way, any slight misalinement which exists between the plug and bore axes is compensated for and the plug comes to rest in the precisely centered position shown in Fig. '2. As the hone completes its down stroke, the spring 38 is further compressed. Then, after part of the next upstroke, the stop 37 encounters the shoulder 36 and picks up the plug which again moves with the spindle during the `upper and major portion of the range of reciprocation of the hone.

The work feeling operation above described is, in the present instance, repeated during each reciprocation of the hone, the beveled surface 34 entering progressively farther into the bore as the latter is enlarged by the hone.

` Finally, on the next downstroke following the attainment of the plug 11 into the up-to-size bore is detected and signaled without any mechanical contact with the plug or the imposition of any overhanging weight or olf-center force which would tend to tilt the plug and thus interfere with the uniformity of its feeling engagement with the bore end at the time of its entry in successive honing cycles. To this end, a magnetic field is established in the path of a mass 46 of metal reciprocable with the plug and disposed remotely from the eld in one of the positions of the plug (Fig. 2), but within the magnetic field in the other or entered position of the plug (Fig. 3). Changes of the character of the eld when the mass of metal is disposed within it are utilized to provide a signal such as closure of a switch 49.

While the sensing means indicated generally at dit may take various forms, it is shown for purposes of illustration as a so-called high frequency carrier-operated transducer or magnetic pick-up unit having a shell 42 composed of non-conducting material enclosing a coil 43 which is associated with a voltage source and an electronic amplier 44. A magnetic pick-up suitable for carrying out the present invention is the so-called Model 4900 manufactured by Electrol Products Laboratories. With this device, a substantially constant output voltage is produced in response to the change in the coil impedance resulting from bringing a metallic mass near the end of the shell 42. The voltage drops to zero when the exciting mass is removed.

In carrying out the present invention, the pick-up unit 41 is mounted stationarily on a bracket 45 attached to the honing machine frame 20 with its end surface disposed parallel to the path of reciprocation of the plug which carries a metallic mass 46 disposed remotely from the unit l1 in one of the positions of the plug, the feeling position (Fig. 2) in this instance, but in close proximity to the pick-up in the other or entered position (Fig. 3). Herein, the metal mass takes the form of a right angular flange substantially larger in diameter than the plug sleeve 32 and upstanding from the periphery of the abutment flange @l on the plug. The radius of the cylindrical flange is somewhat less than the spacing of the pick-up from the spindle axis so that an arc of the ange will come into close proximity to the pickup when the plug enters the work bore as shown in Fig. 3. With the present type of pick-up, the flange 46 may be formed of light metal such as aluminum and pressed onto the spring abutment 40. In this instance, the plug follows the hone into the work bore so that its lowermost position (Fig. 3) is determined by the length of the downstroke of the hone. In this limit position, an arcuate portion of the flange 46 is disposed directly opposite the pick-up irrespective of the angular position in which the plug may be disposed.

The increase in the output voltage resulting from the presence of the exciting metal results in energization of a relay 48 and closure of a switch 49. This signal is utilized in a manner well known in the art to terminate the honing cycle and separate the hone from the finished workpiece.

It will be observed from the foregoing that the plug 30 is relatively light in weight with its entire mass distributed symmetrically around its axis. At the same time, the pick-up unit 41 of the character above described operates without mechanical contact with the plug and without exerting a magnetic or other side force on the plug. The latter is thus subjected only to the endwise force tending to urge it into the finished bore, such force acting along the spindle axis and remaining of uniform magnitude at all times. As a result, the entry of the plug is controlled so accurately that it has been posible in actual practice to consistently produce nished bores with a variation of no more than .0001 in diameter.

This application is a continuation of my copending l application Serial No. 561,483 filed January 26, 1956, now abandoned.

I claim as my invention:

l. In a machine for honing the wall of a bore in a workpiece, the combination of, a rotary spindle, a honing tool thereon, mechanism for reciprocating said spindle to move said tool back and forth through said bore, a sizing plug including a sleeve surrounding and loosely journaled on said spindle so as to be adapted for limited transaxial oating relative to the spindle, means on the end of said sleeve adjacent said tool providing a beveled surface adapted to engage and be stopped at the end of said bore wall when the latter is under a predetermined size but to enter the bore when the wall attains such size, said plug being carried by the spindle alternately into and out of feeling engagement with said wall end during reciprocation of said tool, an electric pick-up device having an output circuit and a sensing element disposed adjacent the path of reciprocation of said plug but at all times out of mechanical contact with the latter, means on said sleeve axially spaced from said bevel surface and providing a metallic mass spaced different distances from said sensing element when said plug is in the stopped and entered positions respectively, and means responsive to current changes in said output circuit produced by changes in the position of said mass and operable to signal the entry of said plug into said bore.

2. In a machine for honing the wall of a bore in a workpiece, the combination of, a rotary spindle, a honing tool thereon, mechanism for rotating said spindle and tool while reciprocating the latter back and forth through the bore, a sizing plug including a sleeve loosely surrounding said spindle and having on the end adjacent the bore a beveled surface adapted to engage and be stopped at the end of said bore wall when the latter is under a predetermined size but to enter the bore when the wall attains such size, said plug being carried alternate.y into and out of feeling engagement with said wall end during reciprocation of said tool, an electric pick-up device having an output circuit and a sensing element disposed adjacent the path of reciprocation of said plug but at all times out of mechanical `contact with the latter, a metallic surface movable with said plug and spaced different dis` tances from said sensing element when said plug is in the stopped and entered positions respectively, and responsive to voltage changes produced in said output circuit by coaction of said metallic mass and said sensing element for signaling the entry of said plug into said bore.

3. In a machine for honing the wall of a bore in a workpiece, the combination of, a honing tool mechanism for rotating said tool while reciprocating the same back and forth through the bore, a plug axially alined with said bore and having on the end adjacent the bore a beveled surface adapted to engage and be stopped at the end of said bore wall when the latter is under a predetermined size but to enter the bore when the wall attains such size, means supporting said plug for limited transaxial floating and carrying the plug alternately into and out of feeling engagement with said wall end during reciprocation of said tool, a magnetic device having an output circuit and a sensing element disposed adjacent the path of reciprocation of said plug but at all times out of mechanical contact with the latter, a metallic mass movable with said plug and spaced different distances from said sensing element when said plug is in the stopped and entered positions respectively, said mass enacting with said sensing element to produce different voltages in said circuit when said plug is in the respective ones of said positions, and means responsive to such voltage changes for signaling the entry of said plug into said bore.

No references cited.

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