US2390495A - Control mechanism for honing machines - Google Patents

Description

Dec. 11, 1945. H. J. CALDWELL 2,390,495

CONTROL MECHANISM FOR HONING MACHINES I Filed Feb. 6, 1943 3 Sheets-Sheet 1 Dec. 11, 1945. H. J. CALDWELL 0, 9

CONTROL MECHANISM FOR HONING MACHINES Filed Feb. 6, 1943 v 3 Sheets-Sheet 2 [72 venior flaw- J Caldwell Dec. 11, 1945. H. J. CALDWELL 2,390,495

CONTROL MECHANISM FOR HONING MACHINES Filed Feb. 6, 1943 3 Sheets-Sheet 3 5&4.

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Patented D... 11, 1945 UNITED STATES PATENT OFFICE ,Harry J. -ciliaweu, Rockford, 111., assignor to Barnes Drill 00., Rockford, Ill., a corporation at Illinois Application February 6, 1943, Serial No. 474,917

5 Claims.

The invention relates to honing or lapping machines and more particularly to improved control mechanism for such machines.

Machines of the above general character are utilized extensively in dressing both internal and external cylindrical surfaces. Such machines employ a cylindrical tool having a series of abrasive elements mounted for movement radially toward and from the surface to be dressed. In practice, the abrasive elements of the tool are normally held in a retracted position to permit the tool and work to be brought into operative relationship without danger of marring the work are properly positioned, tool expansion is initiated, that is, the abrasive elements are shifted radially into engagement with the surface of the work and are forced against the surface with substantial pressure while the tool and work are relatively rotated and simultaneously relatively reclprocated. Relative rotation is continuous in a honing operation and intermittent in a lapping operation.

With the control mechanism heretofore available, considerable time is lost in shifting the abrasive elements from their retracted positions into engagement with the work surface, particularly when the tool expanding mechanism is arranged to effect controlled expansion of the tool, or in other words, to advance the elements at a definite.

rate so as to maintain a predetermined pressure on the work throughout the operating cycle. With this in view, one object of the invention is to provide improvedcontrol mechanism for reducing the time required to condition the tool for actual operation upon the work thereby materially increasing the productive capacity of the machine. 7

A more specific object is to provide novel control means operable at will by the machine attendant for effecting rapid expansion of the tool when desired without interfering with the controlled expansion of the same during the work ing portion of the cycle.

Another object is to provide novel means for visually indicating the extent to which the tool may be expanded at any stage of the honing cycle. I

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

Figure 1 a diagrammatic view of a honing When the tool and work" machine embodying the features of the invention.

Fig. 2 is a side elevational view of the tool expanding and control mechanism of the machine.

Fig. 3 is a vertical sectional view of the mechanism shown in Fig. 2.

Fig.4 is a transverse horizontal sectional view taken along the line 4-4 of Fig. 2 showing also a portion of the machine head to which the control mechanism is attached.

For purposes of illustration, the invention has been shown and will be described herein as embodied in a vertical, multiple spindle, internal honing machine of the type in which the relative rotational and reciprocatory movementsof the tool and work are effected by rotating and simultaneously reciprocating the tool while the work is held stationary. A specific type of hone expanding mechanism has been shown by way of illustration, but it is to be understood that the invention is not limited to use with this-particular mechanism and that it is also readily applicable to other types of machines. It is also to be understood that various modifications and adaptations may be made in the form, construction and arrangement of the parts without departing from the spirit and scope of the invention as expressed in the appended claims.

Referring now to the drawings, the machine selected to illustrate the invention comprises a head ll (Figs. 1 and 4) supported and guided by suitable framework for movement toward and from a stationarily supported workpiece w. Journaled in the head with their axes parallel to its reciprocatory path are a plurality of tubular spindles ll each carrying on its outer end a conventional internal honing tool l2. The spindles are rotatably driven by a suitable prime mover through an elongated spiral toothed gear l3 (Fig. 4) coacting with spiral toothed pinions i4 fast on the respective spindles.

In the particular machine illustrated, the head is reciprocated by pressure fluid actuated means com rising a piston 20 carried on a rod 2i rigidly anchored to the head. ranged to work in a cylinder 22 statlonarily supported on the framework of the machine. Fluid under pressure is supplied to the cylinder by a pump P- under control of a stop valve V and a reversing valve Vi. The pump may be of any suitable type and. as herein shown; is provided with an inlet 23 through which fluid is drawn The piston is an suitable prime mover may be utilized to drive the pump.

The stop valve V is a conventional, two-position, plunger type valve adapted to be operated in any preferred manner. In one Position, the valve is effective to direct the fluid delivered by the pump P back to the reservoir R through a return line or drain 25. In the alternate psi-' tion, the stop valve directs the fluid from the pump P through a pressure line 28 leading to the reversing valve VI A pressure responsive relief valve 21 connected to the pump outlet 24 acts to maintain the fluid in the system at a predetermined pressure.

The reversing valve Vi, also of conventional form, includes a two-position plunger operative to connect the pressure line 26 with either end of the cylinder 22 while connecting the other end of the cylinder to the drain line 25. The plunger of this valve is shifted selectively between its two positions under control of a pilot valve V2 arranged to direct pressure fluid alternately to opposite ends of the valve housing. The pressure fluid supply for this purpose is received through a branch 28 of the main pressure line 28.

The pilot valve is arranged for actuation in response to movement of the head l0, such actuation being effected through the medium of .a control rod 30 reciprocable with the head. For this purpose, the control rod carries a series of dogs or stops including upper and lower limit stops 3i and 32 and an intermediate stop 33. The latter, together with stop 22, defines the upper and lower limits of the working stroke of the head in which the tools are traversed axially through the work. Provision is made for shifting the intermediate stop to an inactive position thereby permitting the head to travel beyond the upper limit of the working stroke to the fully retracted position in which the tools are withdrawn from the work. As the head approaches the retracted position, further movement is interrupted by the upper limit stop 3| acting through the pilot valve and other well known control mechanism. The mode of operation of the control mechanism is well known and a detailed description is therefore believed to be unnecessary.

therethrough above and in alinement with the actuating rods. The shaft is formed with an ec-,

centric cam portion 38 positioned to coact with the projecting ends of the rods 36 and operative to force the rods downwardly-for expanding the tools when the shaft is rocked out of the neutral position in which it is shown in Fig. 1.

Power actuated means of any preferred character may be utilized for rocking the actuator shaft 37 to expand the tools I2. As herein shown, the power means provided for this purpose is of the pressure fluid actuated type comprising a piston 40 (Figs. 1 and 3) working in a cylinder 4|. The piston is connected by a rod 42 with a bar 43 arranged to shift an actuating member 44 rigidly secured to the tool expanding shaft 31. The actuating member, as herein shown, is in the form of a bell crank having arms 45 and 46 projecting radially of the shaft and substantially at right angles to each other. An operative connection between the bar 43 and the arm 45 of the actuating member is provided by rack teeth 41 formed in one face of the bar and meshing with teeth in a segmental extension formed on the end of the arm 45. The actuating member is nonrotatably anchored to the shaft 31 and held in place thereon by a nut 49 threaded on the reduced end portion of the shaft.

A pump P' of any suitable'character, herein shown as driven in tandem with pump P by the motor M, supplies fluid to the tool expanding cylinder 4|. In the present instance an accumulator A is associated with the pump in well known manner to provide a substantial volume of fluid The honing tools I2 may be of any suitable construction and are preferably adapted for power actuation. A tool of this type is disclosed in U, S. Patent 2,271,768 granted February 3, 1942 to A. M. Johnson, to which reference may be had for details of construction. Each tool l2 comprises a cylindrical body in which a series 'of elongated abrasive elements 35 are mounted for movement radially of the body. The elements are normally held in a withdrawn or contracted" position by springs (not shown) and are shifted radially outwardly or expanded" by an axially movable rod 36 extending through the tubular spindle and coasting with cam means enclosed within the body of the tool. Spring means within the spindle normally holds the actuating rod in its upper or tool contracting position.

In the particular form illustrated, the actuating rods 36 of the several tools are extended beyond the inner ends of their respective spindles and into the head III, as shown in Fig. l, for cooperation with power driven expanding mechanism carried on the head. This mechanism as herein shown includes a shaft 31 (Figs. 1 and 4) journaled in the head and extending transversely -let of the pump P.

under pressure for effecting rapid movements of the actuator and associated apparatus. A control valve V3 is arranged to direct the fluid selectively by way of pipes 50 and 5| to either end of 'the cylinder 4| while connecting the other end of the cylinder to the drain line 25. A control rod 52, adapted to be rocked about its longitudinal axis in well known manner in response to movements of the head into or out of the working range, is adapted to control the operation of the valve V3 so as to initiate expansion of the tools upon their entryv into the work and to effect contraction of the tools prior to their withdrawal from the work.

The pressure of the fluid supplied to the actuator cylinder is determined, in this instance, by one or the other of two conventional pressure reilef valves V4 and VI connected with the out- The valve V4 is preferably set to open at the lower working pressure, while the valve V5 is set for the higher working pressure. A shut-oil valve V6 is provided for closing the connection between the pump and the valve V4. Thus, when the valve V6 is closed, the pressure in the system is determined by the setting of the high pressure relief valve V5. When the valve V6 is open, low pressure relief valve V4 is in control. The shut-off valve may be operated in any preferred manner.

Provision is made for controlling the rate of expansion of the honing tool by the action of the pressure fluid actuator so as to enable the tool to operate at its most emcient rate. The particular mechanism herein shown for effecting such control comprises a shiftable abutment member 53 arranged to coact with the arm 46 of the actuator and operative to variably limit the extent of movement thereof in a direction to ex.-

pand the tool. The abutment member is sup- 'sociated elements. gral with or rigidly secured to the side wall of '.of the members, Accordingly, endwise shifting of the member is effective to cause the control surface to advance toward or reced from the arm 45 and thereby determine the extent to which the actuating member may be rocked.- To re-'- duce Irictiomthe arm is provided /with a roller 55 adapted to engage the control surface.

Shifting of the abutment member 53 may be effected by any suitable means. As herein shown, apressure fluid operated actuator is provided for shifting the member, the actuator comprising a piston 50 (Figs. 1 and 3) working in a cylinder and connected by a piston rod 62 with the abutment member.

posed in the lower end of the cylinder 5| and its presence therein substantially reduces the volume of the cylinder and the area of the. piston exposed to fluid actionto facilitate rapid return of the piston and associated parts to the upper or rest position.

-In the particular trated', the tool expanding cylinder 4| and the expansion control cylinder 5| are formed in a common cylinder block 55 adapted to be bolted or otherwise rigidly secured to the top oi. a hous ing 55 enclosing the bar 43, abutment 53 and as- The housing may be intethe head III as shown in Fig. 4.

In order to coordinate the movements of the abutment member 53 with the operation of the rack bar iii, the cylinders II and SI are preferably connected parallel to a common pressure fluid source. As shown in Figs. 1 and 3, the pipe 50 leading from the valve V3 is arranged to open into a passage 51 in the cylinder block 55 having one branch 58 leading to the upper end of the cylinder II and a second branch 59 leading to the corresponding end of the cylinder 5|. An

form of the mechanismillus-.

In a honingoperatiomthe rate of expansion of the honing tool is limited by the rate at which stock is removed from the'surface of the work. Under the most favorable conditions the rate of expansion is relatively slow and, when controlled expansion is employed, as in the exemplary machine, expansion is further restricted by the abut- A plunger 63, which may be formed integrally with piston 50 if desired, is disment member so as to maintain the pressure of the abrasive elements on the work substantially uniform and below the point at which the elements of the tool tend to become loaded with abraded material. In practice, the orifice valve 10 is therefore set to pass a very small quantity of pressure'fluid into the cylinder GI and the rate of movement of the abutment member 53 is consequently quite slow.

\ At the beginning of each honing cycle the honing tool is fully contracted, that is, the a'brasive elements are withdrawn to their inactive positions inorder to facilitate entering the tool in the work. The abutment member 53 is likewise held in the retracted position in which it is shownin i Fig. 3. In this position, the highest point of the by preventing further movement of the actuator.

This initial rocking of the actuator partially expands'the honing tool, but further expansion is orifice valve 10 of any suitable construction 'ad'apt- I ed to be adjusted by means of a hand lever II is interposed in the branch passage 69 for regulating the rate of fluid flow into the cylinder 5|. It will be understood, of course, that the orifice valve may be interposed in the exhaust passage leading from the lower end of the cylinder 4 I. In either instance, by appropriate setting of the oriflce valve, the advance of the piston 50 and the abutment member 53 may be timed as required for each particular job.

The lower ends of the cylinders .II and SI are likewise connected in parallel, in this instance, by a passage "in the cylinder block.' Accordingly, in the downwardmovement of the pistons and 60, fluid is exhausted from both cylinders through the pipe 5| and returned to the reservoir by way of the valve V3 and drain line 25. When the valve V3 is reversed to direct pressure fluid through the pipe 5|, both pistons are forced upwardly. Fluid is exhausted from the cylinder 5| through a passage 13 and check valve 14 which provide a one-way by-pass around the orifice valve. The check valve, herein shown as a spring pressed ball type valve, prevents fluid flow through the passage 13 into the cylinder,

required to bring the abrasive elements into operative contact with the surface of the work. The extent of this further expansion varies with different workpieces and may at times require a preliminary shifting of the abutment member through substantially one-half of its full working stroke.

In order to avoid the lossof time that would result from effecting this preliminary shift of the abutment member under the action of'the expansion control mechanism above described, the invention provides auxiliary control means operable at will to effect a rapid shifting of the abutment member independently of such control mechanism. The auxiliary control means, as constructed for use with expansion control mechanism of the type herein disclosed, is in the form of a pressure fluid circuit including a normally closed shut-off valve V1 arranged to by-pass the orifice valve III and deliver an unrestricted flow of pressure fluid to the upper end of the cylinder 5|. t Referring to Fig. 3, the valve V1, as herein shown, comprises a. housing 15 formed with a central passage I6 having inlet and outlet ports 11 and I8. Inlet port 11 is connected by a pipe 19 with the main pressure fluid passage 61 in the cylinder block 55 to receive pressure fluid from the pipe 50. Outlet port 18 of the valve is connected by a pipe with a port 8| communicating with the upper end of the expansion control cylinder 5|. Communication between the inlet and outlet ports of the valve is normally prevented by a valve member, herein shown as ball 82, yieldably held against its .seat by a spring 83. the valve member is shifted away from its seat (to the left as viewed in Fig. 3) fluid flows unrestrictedlythrough the pipe I9, the valve passage 15 and the pipe 85, into the upper end of the cylinder 5|, thus rapidly shifting the piston 50 and abutment member 53 toward'the tool expanding position.

When i While any suitable means may be utilized for opening the valve V1, it is preferred to employ a remotely controlled actuator for this purpose. The valve actuator, as herein shown, comprises a cylinder 84 suitably supported at one end of the valve body 15. Fitted within the cylinder is a piston 85 having a piston rod 86 extending through the valve body and into the passage 16 to coact with the valve member 82. To shift the piston 85, a fluid medium such as compressed air is introduced into the outer end of the cylinder 84 through a pipe 81 in which is interposed a manually operable valve V8 located at any point conveniently accessible to the machine attendant.

The valve V8 may be of any suitable construc tion and is preferably arranged to vent the pipe 81 to the atmosphere when in its normal or unoperated condition. This permits the piston 85 to return to rest position at the right end of the cylinder under the influence of the spring 83 acting through the valve member 82 and piston rod 88. Operation of the valve V8 closes the vent and connects the pipe 81 to the compressed air line thus directing compressed air to the cylinder 84 with a resultant shifting of the piston 85 to the left. Valve member 82 is thereby moved to the open position to establish the by-pass circuit as above described.

In order to enable the machine attendant to accurately adjust the expansion control mechanism,

means is provided for visually indicating the maximum degree of expansion permitted the honing tool at any time. The indicating means, as herein shown, comprises a pointer 88 carried on the outer end of a shaft 89 journaled on a cover plate 90 forming one side of the housing 66. The pointer is arranged to sweep over an arcuate scale 9| graduated to show the expansibility of the honing tool in any suitable units.

Means is provided for driving the pointer carrying shaft in timed relation with the shifting of the abutment member 53 so that the position of the pointer is accurately coordinated at all times with that of the member. The driving means, as shown in Fig. 4, preferably comprises a gear 92 pinned to the inner end of the shaft 89 and adapted to mesh with a pinion 93 fast on the reduced end portion of a horizontal shaft 94 extending through the housing 66 adjacent the abutment member 53. The shaft 94 is journaled in suitable bearings carried on the housing 66 and cover plate 90. Keyed to the shaft intermediate its ends is a pinion 95 meshing with the teeth of the rack member 96 removably attached to the front face of the abutment member 53. The shaft 94 also carries a roller 91 positioned for engagement by the surface of the abutment member opposite the control surface 54. The roller thus serves to support the member and absorb the thrust of the actuator 44 thereon.

Due to the direct rack and pinion connection between the abutment membe and the shaft 94 and the gear connection between the latter and the pointer shaft 89, the pointer 88 is invariably rocked through an angle proportionate to the displacement of the abutment member from the normal rest position. As the spacing of the control surface from the actuator 44 is dependent upon the position of the abutment member, the pointer is thus effective to indicate the maximum sweep permitted the actuator and therefore the maximum expansibility of the honing tool.

It will be apparent from the foregoing that the invention provides control mechanism of a novel and advantageous character for use with honing tool expanding mechanism of the controlled expansion type. The invention permits the rapid expansion of the honing tool to bring the abrasive elements thereof into working contact with the work surface without the loss of time experienced when expansion is effected solely by the controlled expansion mechanism. The invention also provides novel means for visually indicating the maximum extent to which the tool may be expanded at any stage of the honing cycle, thus permitting quick and accurate adjustment of the control mechanism to meet a wide variety of working conditions.

I claim as my invention:

1. Mechanism for actuating an expansible and contractible honing tool comprising, in combination, an actuating member movable in one direction to expand the tool and in-the opposite direction to contract the tool, power actuated means for imparting movement to said actuating member, a shiftable abutment supported for movement transversely of the path of said actuating member, said abutment having a control surface inclined with respect to its path of movement and positioned for engagement by said actuating member, a pressure fluid actuator operable to shift said abutment and thereby cause the control surface to recede from the actuating member, means for supplying pressure fluid to said actuator, a control valve operative to regulate the flow of pressure fluid to said actuator and thereby determine the rate of recession of the control surface from the actuating member, and other valve means operable to by-pass said control valve and thereby increase the rate of recession of the control surface from the actuating member.

2. Mechanism for actuating an expansible and contractible honing tool comprising, in combination, an actuating member adapted to be rocked in one direction to expand the tool and in the other direction to contract the tool, a pressure fluid operated actuator arranged to rock the member, an abutment supported for movement transversely of the path described by the actuating member when the latter is rocked in said one direction, said abutment having a control surface adapted to be engaged by said actuating member and inclined with respect to the path along which the abutment is moved, -a second pressure fluid operated actuator operative to shift the abutment in a direction to cause the control surface to recede from the actuating member, control means associated with said second actuator normally operative to limit the movement of the abutment to a predetermined rate, and other control means operable at will to condition said second actuator for shifting the abutment at a substantially faster rate than permitted by said first mentioned control means.

3. Mechanism for actuating an expansible and contractible honing tool comprising, in combination, an actuating member movable in one direction to expand the tool and in the opposite direction to contract the'tool, power actuated means for imparting movement to said actuating member, a shiftable abutment supported for movement transversely of the path of said actuating member, said abutment having a control surface inclined with respect to its positioned for engagement by said actuating member, means operative to shift said abutment and thereby cause said control surface to recede from the actuating member, a control device associated with said shifting means adapted to limit the recession of said control surface to a predepath of movement and termined rate, and control means operable at will to render said control device temporarily ineffective and thereby increase the rate of recession of said control surface.

4. Mechanism for actuating an expansible and contractible honing tool comprising, in combination, a member movable in one direction to expand the tool and in the opposite direction to contract the tool, power actuated means for moving said member in said one direction, abutment means positioned for engagement by said member to limit the advance thereof in said one direction, power actuated means normally operative to withdraw said abutment means from said member, a control device associated with said power actuated means adjustable to limit the withdrawal of the abutment means to a predetermined rate and thereby permit the member to advance at a corresponding rate, and control means operative to initiate an increase in the rate of withdrawal of the abutment means without disturbing the adjustment of said control device.

5. Mechanism for actuating an expansible and contractible honing tool comprising, in combination, a member movable in one direction to expand the tool and in the opposite direction to contract the tool, power actuated means for moving said member in said one direction, abutment means positioned for engagement by said member to limit the advance of the member in said one direction, control means operable to effect a, gradual withdrawal of the abutment means from said member to permit a corresponding gradual advance of the member, other control means operable to efiect a more rapid withdrawal of said butment means, and means for rendering one or the other of said control means operable selectively.

HARRY J. CALDWELL.

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