US2671292A - Control mechanism for honing machines - Google Patents

Description

H. J. CALDWELL ETAL CONTROL MECHANISM FOR HONING,.MACHINES March 9, 1954 2 Sheets-Sheet 1 Filed May 23, 1950 g 5 3 km a; 5 M; i

arch 9, 1954 H. J. CALDWELL arm. 2,671,292

CONTROL MECHANISM FOR HONING MACHINES Filed May 25, 1950 2 Sheets-Sheet 2 InVent'bv-J Harv-y J. Caldwell (lav-e St csebcv Patented Mar. 9, 1954 UNITED STATES PATENT OFFICE CONTROL MECHANISM FOR HONING MACHINES Harry J Caldwell and Earnest Y. Seborg, Rockford, Ill., assig'nors to Barnes Drill 00., Rockford, III., a corporation of Illinois Application May 23, 1950, Serial No. 163,578

'7 Claims. I

The invention relates to machines for finishing elongated bores by a honing or lap-ping operation, and more particularly to control mechanism for such machines. 7

In a honing or lapping operation a radially expansible cylindrical abrasive tool and a workpiece are relatively rotated and simultaneously relatively reciprocated axially of the bore in the workpiece which is to be finished. During such rotation and reciprocation, the abrasive elements of the tool expand into operative engagement with the walls of the bore. The amount of material removed from the bore walls and thus its finished diameter is determined in part by the number of times the tool is traversed over the walls. It will be apparent, therefore, that when the tool is traversed only part way through the bore, more material will be removed from the walls adjacent the entering end than from the opposite end, with a corresponding increase in the diameter of the bore at such entering end.

The primary object of the present invention is to provide improved control mechanism whereby the above principle may be utilized to advantage in generating tapered or stepped surfaces in bores initially machined to cylindrical contour.

More specifically stated, an object of the invention is to provide control mechanism operative automatically to reduce the length of the tool stroke progressively by predetermined increments so as to generate a bore of gradually increasing diameter.

Another object is to provide a control mechanism of the above general character which is readily adjustable to produce a; wide range of surface finishes including, on one hand, a finish in which the stepped areas of the surface are so short measured axially of the bore as to afford a substantially uniform taper from one end of the bore to the other, or alternatively, a finish in which the stepped areas are relatively long and prominent.

It is also an object of the invention to provide stroke control mechanism for honing machines which is simple in construction, eflicient' and dcpendable in operation and which can be applied to conventional honing machines to increase their utility without afiecting their normal mode of operation.

Other objects and advantages of the invention will become apparent from the following detailed description of the preferred embodiment illus trated in the accompanying drawings, in which:

Figure 1 is an elevational view of a control mechanism embodying the feature of the inven- 2 tion, the mechanism being shown as applied to a conventional horizontal honing machine. v v

Fig. 2 is a fragmentary sectional view taken in a vertical plane substantially on the line 2-4 of Fig. 1.

Fig. 3 is a. fragmentary sectional view taken in a horizontal plane substantially on the line 3-3 of Fig. 1. v

Fig. 4 is a diagrammatic view showing the electrical and hydraulic operating control cir+ cults of the machine shown in Fig. 1. I

While the approved controls are applicable to various types of honing and lapping machines, they are particularly suitable for use with machines designed for operating on long workpieces which are desirably handled in a horizontal po sition. It will be understood, of course,- that various changes and modifications may be made in the form, construction and arrangement of the parts of the control mechanism without depart ing from the spirit and scope of the invention as expressed in the appended claims.

For purposes of illustration, the invention has been shown as incorporated in a horizontal hon ing machine of the type disclosed in the Caldwell Patent No. 2,247,479 issued July 1, 1941, in which the work is stationarily supported and the honing tool is rotated and reciprocated relative thereto. The exemplary machine comprises an elongated, horizontally disposed bed It (Fig. 1) having means at one end for supporting a work piece W (Fig. 4) formed with a bore B to be" finished, and having means at the other end for supporting a honing tool T. The tool support comprises a head or carriage ll mounted for reciprocation so as to traverse the tool T anially of the bore B. The tool T is carried on the pro jecting end of an elongated driver I2 secured to and rotatable with a spindle l3 journalled on the head II. A motor M mountedon the head is operative through suitable gearing eaclosed Within a housing [4' to rotate the spindle [3 either continuously or intermittently.

The tool T, as shown, is a conventional honing tool having a cylindrical body 15' about which are arranged a series of elongated,- longitudi nally disposed abrasive elements l6, These abrasive elements are movable radially of the tool body into and out of operative engagement with the walls of the bore. Such movements of the abrasive elements to expand or contract the tool may be effected in any preferred manner;- as;

for example; by power operated mechanism such 2,171,261- issued- August 28,1939.

Suitable power operated means is provided for reciprocating the head The reciprocating means as shown in Fig. 4 comprises a pair of flexible members or cables 20 and 2|, each anchored at one end to an arm 22 depending from the head and at the other end to a cable drum 23 rotatably supported adjacent the end of the bed l remote from the work support. The cable leads directly from the head to the drum while the cable 2| is carried over a sheave 24 rotatably supported on the bed I8 below the work support. The arrangement is such that rotation of the drum 23 first in one direction and then in the other direction is effective to move the head toward and from the work, or in other words, to reciprocate the head.

Rotation of the cable drum 23 is preferably effected by means of a hydraulic motor HM, herein shown as drivingly connected with the drum through the medium of gearing 25. Pressure fluid is supplied to the motor HM by a motor driven pump P under control of a reversing valve RV. The particular reversing valve illustrated is pressure fluid operated under control of a pilot valve PV which, in turn, is actuated mechanically as an incident to the reciprocation of the head I The mechanism for actuating the pilot valve PV as herein shown comprises an elongated control rod 28 extending along the side of the bed l0 parallel to the path of reciprocation of the head H and supported on the bed to rock about its longitudinal axis. Such movements of the control rod are transmitted to the movable member of the pilot valve through the medium of a gear 21, pinion 28, rockshaft 29, crank arm 3!], link 3| and crank arm 32 associated with such movable member. rocked alternately in opposite directions, the pilot valve PV is shifted to set the reversing valve RV for initiating the forward and return movements of the head.

The rocking of the control rod is effected by the head through the medium of a pair of cam elements 34 and 35 reciprocable with the head and engageable respectively with a pair of actuating members comprising, in this instance, a rear dog 31 and a front dog 38 operatively associated with the control rod. As herein shown, the cams 34 and 35 are carried by an arm 39 depending from the head, the cams being opposedly faced so as to shift the dogs in opposite directions. More particularly the arrangement is such that th cam 34 engages the dog 3'! to rock the control rod in one direction (for example, counterclockwise) as the head approaches the end of its stroke whil moving toward retracted position, or to the right as viewed in Fig. 4. As the head approaches the other end of its stroke, the cam 35 engages the dog 38 to rock the control rod in the opposite direction.

The dogs 3! and 38 may be alike, in construction. In the exemplary embodiment, each comprises an arm 40 rigidly clamped to and projecting radially from a shaft 4| supported for rocking movement in a bracket 42 at the side of the machin bed adjacent the contro1 rod. A follower roller 43 is desirably provided on the outer end of each arm 48 for engagement by the associated cam.

Each shaft 4| carries a segmental gear element 44 meshing with longitudinal teeth or splines 45 formed on the control rod. With this arrangement, the rocking movement imparted to either dog by engagement of its cam correspondingly rocks the control rod and thus shifts the-pilot Thus, as the control rod is valv between forward and return stroke positions.

The toothed connection between the control rod 26 and the dogs 31 and 38 permits the latter to b mounted for adjustment longitudinally of the rod whereby to change the limit positions of the head II at opposite ends of its stroke. For this purpose the brackets 42 which support the two dogs 31 and 38 are mounted respectively on carriers 46 and 41 which are slidably supported on a guide bar 48 extending longitudinally of the bed If] below the control rod.

The carrier 46 may be conveniently constructed in the form of a channel shaped memu ber presenting inwardly facing bearing surfaces at its upper and lower ends for sliding engagement with the corresponding surfaces of the guide bar 48. A tapered gib 49 adjustable by means of a screw 50 is provided between the upper bearing and guide surfaces for insuring a snug fit and for taking up wear. In operation the carrier 46 may be securely clamped in a fixed position of adjustment, as by means of clamp screws 5|.

The carrier 4! is generally similar to the carrier 46 in having upper and lower bearing surfaces cooperating with the corresponding guide surfaces of the guide bar 48. A tapered gib 52 and adjusting screw 53 is provided for adjusting the fit between the bearing and guide surfaces and for taking up wear.

In accordance with the invention, control of the tool stroke for distributing tool action in the manner required to generate a tapered or stepped surface is effected by shifting the carrier 41 and with it the front dog 38 so as to periodically decrease the length of the forward stroke by predetermined increments. Accordingly the tool action on successive areas of the workpiece and therefore the amount of material removed from such areas increases progressively from the smaller toward the larger end of the bore as to produce a tapered or stepped configuration.

The means for shifting the dog carrier 4'! is. of course, power actuated and, as herein shown, comprises an electric motor Ml mounted on the outer face of'the carrier and adapted to rotate a transverse shaft 55 extending through and journaled on the carrier as shown in Figs. 1 and 3. This shaft is provided on its inner end with a pinion 56 meshing with a rack 51 mounted on the underside of the guide bar 48.

The drive for the shaft 55, in this instance, includes conventional speed reduction gearing 51' (Fig. 4) enclosed in a housing 58, a pinion 59 and a gear 60 rotatably mounted on the shaft 55 between a collar 6| and a clutch element 62 slidably but non-rotatably coupled to the shaft as by a key 63. The inner end of the clutch element and the adjacent face of the gear 50 are formed with cooperating clutch teeth 64 of which the rotative movements of the gear are transmitted to the clutch element and by the latter to the shaft.

Through the medium of a nut 65 threaded on the outer end of the shaft, the clutch element 62 may be shifted into or out of engagement with the gear. With the clutch elements disengaged, the shaft 55 may be rotated manually through the medium of a hand crank applied to its squared outer end.

In generating a tapered or stepped surface, it is usually desirable to vary the tool stroke in in crements of uniform length and to effect such variations 'intimed relation to the reciprocation actress of the tool, as for example, at the end of either a forward or return stroke. To this end. provision is made for initiating the operation of the motor M! as an incident to the reciprocation of the head II. Such control may be effected by means of a suitable switch S (Fig. 4) mounted on the machine bed It for actuation by the head as it passes a predetermined point in'its travel, pref erably as it approaches the limit position of its return stroke.

Through the medium of novel auxiliary control mechanism, the length of the increment of change of the tool stroke and also the interval between such changes may be varied as required by the character of the material being worked on and by the particular surface contour to be produced thereon. For determining the interval between stroke changes and therefore the number of working strokes applied to a selected area of the work, the switch S is arranged to actuate a stroke counter C which, in turn, initiates the operation of the motor M I. This stroke counter may be of any preferred type operative in response to a predetermined number of switch actuations to close a normally open switch S I. The counter, of course, is selectively adjustable by means of a knob or dial (it to effect closure of the switch SI following any desired number of actuations of the switch S.

For determining the extent of movement of the dog carrier ii and thus the length of the increment by which the tool stroke is changed, provision is made for independently controlling its operating period. In this instance, closure of switch Si by the counter C is arranged to initiate the operation of a timer T simultaneously with the starting of the motor MI. The timer T may be of any preferred construction and is preferably arranged to immediately close a switch S2 and to maintain that switch closed for a predetermined interval as determined by the setting of a selector knob or dial 61. Switch S2 when closed completes an energizing circuit for a solenoid SOL which closes a switch S3 to complete the operating circuit for the motor Mi. At the end of the interval determined by the setting knob er, timer switch S2 is opened to interrupt the circuit for the solenoid SOL which becomes disenergized and stop the motor MI.

The various electrical elements of the control mechanism are desirably mounted on the machine bed it. for convenient access by the machine attendant. When so mounted, electrical connection with the motor Ml on the movable carrier a": may be effected through the medium of sliding contact elements or brushes H! (Fig. 4) carried by an arm ll (Fig. 1) depending from the carrier. The brushes cooperate with contact strips i2 extending longitudinally of the machine bed 10.

It will be apparent that with the above arrangement the controls may be set to effect reciprocation of the tool through a series of strokes which progressively decrease in length. The number of strokes of any one length and thus the amount of tool action on a particular area of the work may be selectively determined by the setting of the stroke counter C. The operating interval of the motor MI and thu length of the increment of change in the length of the tool stroke may be varied by adjustment of the timer T. In other words, the stroke counter C and timer T provide convenient means whereby the frequency of changes in the tool stroke and the increment of change in the length of the strokes may be varied as required by the character of the work and particular finish to be produced thereon. Thus. when desired, adjustment of the dog 38 may be effected in very small steps with correspondingly small increments of'change in the tool stroke. Withsuch small increments of change, the successive surfaces produced on the work are so short measured axially of the work a to produce the effect of a substantially continuous tapered surface. Alternatively, by setting the timer T for a substantially longer operating period, the dog 38 may be shifted farther so as to amplify the increment of stroke reduction and thus produce successive stepped areas of substantial length.

Before a honing operation is started, the stroke counter C and timer '1 are ordinarily preset to produce the desired surface contour. It will be appreciated that those settings can be changed at any time if uniformity between the successive stepped surfaces is not required. 7

It will be apparent from the foregoing that the invention provides novel control mechanism for automatically varying the reciprocating stroke of a honing tool to distribute the tool action over the surface of a workpiece for producing a tapered or stepped contour thereon. The mechanism is simple in construction, free of parts that are sub-.

ject to wear or likely to get out of order, and is quickly and easily adjustable to meet a wide range of operating conditions. In this connection it. will be noted that the mechanism is adjustable to vary both the number of operating strokes applied to a selected surface of the work and also to vary the length of such surface as desired. Furthermore, the mechanism is readily attachable to conventional honing machines or other. comparable machines without affecting their usual mode of operation, since the automatic control mechanism may be temporarily disconnected or shut off, thus allowing the regular controls to function in the normal manner.

We claim as our invention:

1. In a honing machine having relatively rotatable and relatively reciprocable work and tool supports, in combination, means operatively connected in driving relation to the reciprocable support, control mechanism operatively connected with said driving means including a control rod supported to rock about its longitudinal axis, a pair of control dogs positioned so as to be rocked in opposite directions respectively as the reciprocable support approaches opposite ends of its stroke, a gear element coupled to and rocked with each dog, and circumferentially spaced teeth formed in said control rod operatively engaging said gear elements whereby the rocking movements of said dogs are transmitted to the control rod.

2. In a honing machine having relatively rotatable and relatively reciprocable work and tool supports, in combination, means operatively connected in driving relation tothe reciprocable support, control mechanism operatively connected to said driving means including a control rod supported to rock about its longitudinal axis, circumferentially spaced teeth extending longitudinally of said control rod, a pair of control dogs positioned so as to be rocked in opposite directions respectively as the reciprocable support approaches opposite ends of its stroke, a gear element coupled to and rotatable with each of said dogs, and means supporting said dogs with said gear elements in engagement with the teeth on said control rod, the supporting means for one of said dogs being adjustable longitudinally of said control rod to change the length of the stroke executed by the reciprocable support.

3. In a honing machine having relatively rotatable and relatively reciprocable work and tool supports, in combination, means operatively connected in driving relation to the reciprocable support, control mechanism operatively connected to said driving means including a control rod supported to rock about its longitudinal axis, circumferentially spaced teeth extending longitudinally of said control rod, a pair of control dogs positioned so as to be rocked in opposite directions respectively as the reciprocable support approaches opposite ends of its stroke, a gear element coupled to and rotatable with each of said dogs, a carrier supporting each dog with its associated gear element operatively engaging the teeth on said control rod,one of said carriers being shiftable longitudinally of the control rod for changing the length of the stroke executed by the reciprocable support, and alternatively available power and manually operable actuators for shifting said one carrier.

4. In a honing machine, the combination of, a reciprocable support, a member movable back and forth along a predetermined path in unison with said support, a pair of limit control devices spaced apart along said path for alternate acuation by said member and each operable when actuated to reverse the direction of movement of said support, one of said devices being mounted for movement toward and away from the other device, a power actuator connected to said one device and operable when energized to move the same along said path, means including an element actuated by said support at a predetermined point in the movement of the latter to energize said power actuator thereby to move said one device and change the length of the stroke of said support, and means for deenergizing said power actuator after a predetermined movement of said one device.

5. Mechanism for a honing machine as defined in claim 4 in which said power actuator is deenergized by a timer operated automatically as an incident to the energization of the power actuator.

6. Mechanism for a honing machine as defined in claim 4 in which said power actuator is energized by a counter actuated by said element and operable after a predetermined number of strokes of said support to energize the power actuator and move said one device.

7. In a honing machine, the combination of, a reciprocable support, a member movable back and forth along a predetermined path in unison with said support, first and second control devices spaced apart along said path for alternate actuation by said member and each operable when actuated to reverse the direction of movement of said support, said first device being mounted for movement along said path, a power actuator connected to said first device and 0perable when energized to move the same along said path toward said second device, means including an element actuated by said support at a point in the movement of the latter adjacent said second device to energize said power actuator when said member is remote from said first device thereby to move said first device toward said second device before the next actuation of the same by said member, and means for deenergizing said power actuator after a predetermined movement of said first device.

HARRY J. CALDWELL. EARNEST Y. SEBORG.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 466,739 Finnegan Jan. 5, 1892 1,884,985 Van Hamersveld Oct. 25, 1932 1,945,044 Johnson Jan. 30, 1934 1,954,155 Vlchek Apr. 10, 1934 1,954,157 Vlchek Apr. 10, 1934 2,111,784 Johnson Mar. 22, 1938 2,247,479 Caldwell July 1, 1941 2,324,727 Shartle July 20, 1943 2,352,183 Bullard June 27, 1944 2,575,031 Smith Nov. 13, 1951

Images