US3780765A

US3780765A - Restrictive flow regulating valve and control circuit employing same

Info

Publication number: US3780765A
Application number: US00172137A
Authority: US
Inventors: E Swatty
Original assignee: Fluid Controls Inc
Current assignee: Fluid Controls Inc
Priority date: 1971-08-16
Filing date: 1971-08-16
Publication date: 1973-12-25
Anticipated expiration: 1990-12-25
Also published as: PL100521B1

Abstract

The restrictive flow regulating valve has a plug which is adjustable axially of a complementary valve sleeve to expose different lengths of a slot in the plug, dependent on the adjusted position of the plug, for predetermining different basic flows. The plug and sleeve have a lapped fit. Concentricity of the plug and sleeve is assured during valve assembly by driving the plug into the sleeve while the sleeve is held in the valve body for limited radial movement with its passage normal to the plug axis so that the plug itself moves the sleeve into coaxial relation with the plug. The sleeve is then secured in coaxial relation in the body while so held by the plug. The valve is incorporated in an electro-mechanically operated hydraulic control circuit which controls the cycling of a cutting machine for rapid advance to feed starting position, and slower advance during feed and, optionally, for successive increments of the feed by which the tool cuts progressively deeper into the workpiece, each increment of feed being followed by rapid withdrawal of the tool to clear the chips and each withdrawal being followed, in turn, by a rapid advance to just short of the beginning of the next increment of cut. The entire control is mounted on the machine itself so that it can remain fully installed relative thereto hydraulically and electrically if the machine is to be moved to a new worksite.

Description

United States Patent [1 1 Swatty Dec. 25, 1973 RESTRICTRVE FLOW REGULATING VALVE AND CONTROL CIRCUIT EMPLOYING SAME [75] Inventor: Eugene E. Swatty, Euclid, Ohio [73] Assignee: Fluid Controls, Inc., Mentor, Ohio [22] Filed: Aug. 16, 1971 [21] Appl. No.: 172,137

[52] US. Cl 137/613, 137/6253, 251/208 [51] lint. Ci. F16k 31/143 [58] Field of Search 251/120, 121, 361, 251/208; 137/613, 625.3

[56] References Cited UNITED STATES PATENTS 3,349,798 10/1967 Allen l37/625.17

694,773 3/1902 Morris 251/361 2,160,582 5/1939 Brugma 137/613 X 3,120,243 2/1964 Allen et a1. 137/6253 X 3,506,242 4/1970 Aunspach 251/361 3,511,470 5/1970 Beckett et a1 251/121 Primary Examiner-Irwin C. Cohen Attorney-John Harrow Leonard [57] ABSTRACT The restrictive flow regulating valve has a plug which is adjustable axially of a complementary valve sleeve to expose different lengths of a slot in the plug, dependent on the adjusted position of the plug, for predetermining different basic flows. The plug and sleeve have a lapped fit.

Concentricity of the plug and sleeve is assured during valve assembly by driving the plug into the sleeve while the sleeve is held in the valve body for limited radial movement with its passage normal to the plug axis so that the plug itself moves the sleeve into coaxial relation with the plug. The sleeve is then secured in coaxial relation in the body while so held by the plug.

The valve is incorporated in an electro-mechanically operated hydraulic control circuit which controls the cycling of a cutting machine for rapid advance to feed starting position, and slower advance during feed and, optionally, for successive increments of the feed by which the tool cuts progressively deeper into the workpiece, each increment of feed being followed by rapid withdrawal of the tool to clear the chips and each withdrawal being followed, in turn, by a rapid advance to just short of the beginning of the next increment of cut.

The entire control is mounted on the machine itself so that it can remain fully installed relative thereto hydraulically and electrically if the machine is to be moved to a new worksite.

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RESTRICTIVE FLOW REGULATING VALVE AND CONTROL CIRCUIT EMPLOYING SAME BACKGROUND 1. Field of the Invention Restrictive flow regulating valve and machine tool hydraulic control employing the valve.

2. Description of Prior Art Precision restrictive flow regulating valves and uses thereof in hydraulic control circuits are known in the art. The prior types of valves are very costly to manufacture, particularly because of the difficulty of obtaining true concentricity of the valve plug and the complementary sleeve or seat in the valve body.

The prior control circuits employing flow control valves are unnecessarily complicated and expensive, and are subject to malfunctioning, due to some extent to the prior types of regulating valves employed.

Further, prior hydraulic controls have been arranged in cabinets or enclosures located adjacent to the machine to be controlled. These controls generally require partial disassembly, reassembly, and readjustment whenever the machine is moved to a new worksite.

Such controls have been used for drill presses. In general, in drill presses, the drilling operation for a shallow cut requires but a single advance and retraction of the drill. For deeper drilling operations, one or more socalled steps are required in which the drill is fed only partway of the full depth of cut at each step, then is retracted to remove the chips, and then is again advanced in the next succeeding step to cut progressively deeper.

The advances and retractions usually are arranged so that on the first advance the drill is moved rapidly to starting position in which the point of the tool is at, or closely adjacent to, the surface of the workpiece to be drilled. The drill is driven more slowly on the feeding or cutting stroke at a rate determined by the rotary speed, type of metal, diameter and type of drill, and the like, and then is retracted rapidly entirely out of the partially drilled bore to remove the chips. It is next advanced rapidly almost to the bottom of the preceding cut, and then fed at cutting speed into initial contact with the bottom of the partially drilled bore for initiating the next drilling cut. It is then fed at the usual cutting feed speed and again fully retracted, and so on through as many successive cuts and chip removing operations as may be necessitated by the particular drilling operation.

For purposes of illustration, the valve and control are shown in connection with a conventional drill press and are arranged so as to cause, in preselected cycles, a succession of progressively deeper cuts, each out being followed by a full retraction of the tool for chip removal.

One of the principal objects of the present invention is to provide a restrictive flow regulating valve which can be produced economically, and to a method of manufacturing the same, which assures extreme precision in alignment of the valve plug and its complementary valving sleeve and seat.

A more specific object resides in the provision of an electro-mechanically controlled hydraulic circuit which includes the valve and can be set to repeat preselected operating cycles rapidly and accurately.

Various other objects and advantages of the present invention will become apparent from the following description wherein reference is made to the drawings, in which:

FIG. 1 is a top plan view of a restrictive flow regulating valve embodying the principles of the present invention;

FIG. 2 is a fragmentary longitudinal sectional view of the valve and is taken on the line 2-2 of FIG. 1;

FIG. 2A is an enlarged fragmentary sectional view of a portion of the valve illustrated in FIG. 2;

FIG. 3 is a fragmentary cross sectional view of the valve taken on the line 3-3 in FIG. 2;

FIG. 4 is a diagrammatic perspective view of the hydraulic drive and the mechanical control elements and electrical switches of the control for controlling the drive of a drill press, the press being shown diagrammatically therein in dash lines for purposes of illustration;

FIG. 5 is a hydraulic diagram illustrating the hydraulic control circuit of the present invention;

FIG. 6 is a schematic wiring diagram showing the electrical control circuit of the present invention; and

FIG. 7 is a diagrammatic illustration of a cycle of successive cuts, showing the relation of the successive starting positions of the drill.

Referring first to FIGS. 1 and 2, the restrictive flow regulating valve V of the present invention comprises a body 1 having an inlet bore 2 communicating with an internal bore 3 which, in turn, through a valving mechanism, communicates with a coaxial internal bore 4 of smaller diameter than the bore 3. The bore 4, in turn, is connected to an outlet bore 5 such that, when the valve is open, hydraulic fluid can flow from the inlet bore 2 out through the outlet bore 5 under the control of the valving mechanism.

Mounted in the

bores

3 and 4 is a removable sleeve element 6 of frusto-conical shape having near its larger base a peripheral radial flange 7 of which the end faces are in parallel planes normal to the axis of the sleeve element.

The element 6 has a basal extension which projects a short distance into the bore 3 when the flange 7 is secured in operating position. At one face, the flange 7 seats on an annular shoulder 8 at the juncture of the

bores

3 and 4 and normal to their common axis. Thus the shoulder 8, by engagement with the flange 7, holds the element 6 with the axis of its frusto-conical portion parallel to the common axis of the

bores

3 and 4.

The element 6 is held in place in the body by an externally threaded header plug 9 which is in threaded engagement with internal threads in the bore 3, the joint being sealed by an O-ring, as illustrated. The plug has a cavity 10 at its inner end and lateral passages 11 connecting the cavity with the bore 3. The liner end of the plug 9 engages that face of the flange 7 which is opposite from the shoulder 8 and holds the flange firmly seated against the shoulder 8 in metal to metal contact. The shoulder 8 and adjacent face of the flange 7 are preferably precisely ground or lapped for assuring that they can provide a tight metal to metal seal and can hold the sleeve element 6 with its axis parallel to the axis of the

bores

3 and 4. For this purpose, the element 6 is made of hardened steel which can be lapped to an extremely precise polished finish.

Mounted in the plug 9 for movement axially thereof to open and closed positions is a settable valve member, indicated generally at 12. The valve member 12 comprises an externally threaded stem 13 which is in threaded engagement with an internally threaded bore 14 in the plug 9 and which extends outwardly beyond the outer. end of the plug 9 and carries on its outer end a knurled adjusting knob 15. Rotation of the knob in opposite directions advances and retracts the valve member 12 axially of the

bores

3 and 4. The valve member 12 is provided with an O-ring seal 16 between its ends for preventing the escape of pressure fluid through the bore 14.

The valve member 12 has a valve plug 20 which is coaxial with, and integral with, the stem 13. The plug 20 is cylindrical and tits into a coaxial bore 21 through the smaller base of the element 6. The plug 20 fits the wall of the bore 21 with a precise lapped fit so close that it prevents the passage of liquid between the exterior peripheral surface of the plug 20 and the wall of the bore 21, as is described hereinafter.

The plug 20 has an internal dead-end bore 22 having its open end at the inner end of the plug 20. One or more longitudinal extending radial slots 23 are provided in the plug 20 and extend through its peripheral wall and open throughout most of its length into the bore 22, thus forming a passage through the valve when the plug 20 is retracted to any degree from its closed position.

The member 12 has a frusto-conical seat 24 with its smaller base at the outer end of the cylindrical plug 20 and of the same diameter as the plug 20. As the valve plug 20 is moved to closed position, the seat 24 seats against the wall of the outer open end of the bore 21 and thereby closes the bore 21. The slots 23 extend from the inner open end of the plug 20 a substantial distance lengthwise of the plug, but terminate a little short of the inner end of the seat 24.

By rotating the operating knob 15 in opposite directions, selectively, the plug 20 can be advanced to fully extended position in which the seat 24 is in sealed position and cuts off entirely the flow of any liquid through the valve, and to retracted positions wherein the liquid flows from the inlet 2 through the slots 23 into the dead-end bore 22 and therefrom through the bore 4 to the outlet 5. The size of the passage for liquid is determined by the length of that portion of the slots 23 exposed in the hollow inner end of the plug 9 for receiving liquid from the bore 3. In the fully retracted position of the plug 20,. the slots 23 are ample to accommodate a relatively free flow of liquid from the inlet 2 to the outlet 5.

An important feature of the valve is the precise fit of the plug 20 in the bore 21. As mentioned, the element 6 and plug 20 are made of hardened steel. During manufacture the cylindrical surface of the plug 20-is ground precisely to shape and diameter. The wall of the bore 21, beginning at its entrance end and extending for about ten thousandths of an inch in a direction toward its outlet end is cylindrical and preferably about one thousandth of an inch smaller in diameter than the cylindrical surface of the plug 20. Beyond this short cylindrical portion of its wall, the bore is frusto-conical, expanding very slowly in the direction away from the entrance end toward the bore 4. The cylindrical surface of the plug 20 and entrance portion of the wall of the bore 21 are then lapped to a precise co-axial fit.

Here it is to be noted that heretofore great difficulty has been experienced in making such a cylindrical plug surface and the surface of its receiving sleeve bore precisely coaxial. While this can be done by conventional methods, such as polishing the plug exteriorly of the body to a shape and size for. fitting a polished bore wall in fixed position in the valve body, the operation is slow and expensive, and even when extreme care is exercised, a large number of rejects customarily result from lack of precise shape and concentricity.

In accordance with the present invention, the plug 20 and the entrance portion of the wall of the bore 21 are lapped together to a precise fit before both the plug 20 and element 6 are installed in the body 1. The element 6 is then placed in the bore 3 with the flange 7 resting in metal to metal contact against the shoulder 8 between the

bores

3 and 4 and with the entrance end of the bore 21 facing the plug 20. The plug 9, with the valve stem 13 threaded therein, and with the plug 20 in advanced position relative to the plug 9 is screw-titted into the body bore 3. With the plug 20 in advanced po-' sition, its cylindrival surface is pushed partly into the lapped entrance portion of the bore 21 of the element 6 before the plug 9 has engaged the flange 7 sufficiently to cause any appreciable resistance to shifting of the element 6 radially.

Since the element 6 can shift radially and since the cylindrical surface of the plug 20 and the entrance wall of the bore 21 have been lap fitted, before this assembly, to precise roundness and diameter, the plug 20 will shift the element 6 radially in the body so that the coacting cylindrical entrance wall of the bore 21 and the cylindrical wall of the plug 20 are precisely coaxial. While the element 6 is held by the plug 20 in this condition, the plug 9 is screwed farther into the body so that its inner end engages the flange 7 and clamps the flange firmly in position between the inner annular end of the plug 9 and the shoulder 8, thus securing the element 6 in a position in which the entrance wall of the bore 21 is exactly concentric with the plug 20.

The bore 21 and open end of the bore 22 communicate with passages 25 in the element 6. The passages 25 communicate with the bore 4 and therethrough with the outlet bore 5.

The structure thus far described provides for adjustment for preselected basic flows, determined by the setting of the plug 20 axially by the knob 15.

In addition to this selective adjustment, the flow through the valve is automatically varied within certain limits by the differential in pressure between the inlet 2 and outlet 5. For this purpose a piston or spool 30 of hardened steel is mounted in the bore 4 for reciprocation endwise thereof. The spool 30 is urged to a retracted position in the bore 4, as illustrated in FIG. 2, by means of a spring 31 which is supported on a suitable pin 32 connected in fixed coaxial relation with the element 6.

In order to render the valve responsive to the pressure of fluid in the inlet 2, the inlet is connected by coaxial communicating

bores

33 and 34 and a lateral duct 35 with the bore 4 at the outer or head end of the spool 30. Thus hydraulic pressure fluid entering through the bore 35 drives the spool 30 to the left in FIG. 2 against the force of the biasing spring 31. The biasing spring 31 is selected as to strength for a given working range of pressures in connection with which the valve is to be used. The bore 4 has. an outlet port 37 which opens into the bore 5 to the left of-the spool 30 when the spool 30 is fully retracted, as illustrated in FIG. 2. When the pressure in the inlet 2 exceeds a preselected minimum, it forces the spool 30 to the left in FIG. 2. As the pressure progressively increases above the minimum; the spool is 'driven progressively furtherto the left. thus covering progressively more of the port 37 and thereby progressively reducing the effective passage for fluid from the bore 4 through the outlet bore 5.

MECHANICAL CONTROL STRUCTURE The mechanical control structure is illustrated diagrammatically in FIG. 4, and comprises a rigid support or panel 40 having reinforcing channels 41 secured to its rear face and having a front mounting panel 42 secured in forwardly spaced relation from the forward face of the support 40 by means of suitable bolts and spacers, such as indicated at 43. The support 40 also includes an end plate 44 to which main power cylinder 45, for advancing and returning the drill, is secured by suitable bolts 46. A piston 47 is reciprocable in the cylinder 45 and has a piston rod 48 extending through a suitable hold in the plate 44. A rack 49 is connected to the outer end of the rod 48 and is slidably secured on the support 40 for movement endwise parallel to the piston rod 48. The rack 49 is in driving engagement with a pinion 50. The pinion is mounted on, and for rotation with, a shaft 51 carried by the support 40. As is well known in the art, the drill press, indicated generally at 52, has a shaft 53 with a radial handle 54 by which the shaft 53 can be rotated for advancing and returning the quill. The shaft 51 is connected to the shaft 53 for co-rotation therewith. The shaft 53 carries a pinion 55 which is drivingly connected to a rack 56 on the spindle quill 57 of the press for advancing the quill downwardly for rapid advance and for feeding, and for retracting it upwardly for chip removal and to starting position.

The cylinder 45 is provided at opposite ends with

pipes

58 and 59, respectively, by which the cylinder is connected in a reversible hydraulic circuit for extending and retracting the piston 47 and thereby the rack 49.

As best illustrated in FIG. 4, a mechanical memory mechanism is provided. This mechanism comprises a cam bar 60 which is connected by a suitable bracket 61 to the rack 49 and is mounted in a guide slot on the sup- 7 port 40 for movement endwise of, and in fixed position relative to, the rack 49. Slidably mounted on the cam bar 60 is a memory dog 62. In order to prevent accidental shifting of the dog 62 on the bar 60 by light noncontrol forces, a suitable spring biased frictional drag shoe, not shown, may be mounted within the dog 62 and bear against a face of the cam bar 60. The spring strength is such that the dog 62 can remain in fixed position relative to the cam bar while performing its switch operating operations, but can be moved for resetting by imposing forces thereon greater than required for switch operation.

The cam bar 60 is provided with a plurality of lateral bores 68 arranged in a row which extends lengthwise of the cam bar 60. The bores 68 open through the forward face of the bar 60 so as to receive, selectively, a trip pin 69. The bores 68 are preferably internally threaded, as is the received end of the pin 69, so that the pin can be screwed into the bores 68, selectively, and thereby held fixedly in position in the selected bore. The pin 69 is for stopping the rapid return of the quill when the point of the drill is returned to the original starting position in which the drill point is at or close to the surface of the workpiece into which a bore is to be drilled, and for initiating the start of the quill on its rapid advance stroke to the cut starting position for the next increment of cut.

The dog 62 has a longitudinal slot 70 through its forward wall to afford relative passage of the dog 62 and pin 69 as the dog is slid along the cam bar 60. A pin 71 is mounted on the front panel 42 in a preselected position in which it engages a finger on the memory dog 62 and arrests the travel of the dog 62 with the cam bar 60 when the piston has moved a predetermined distance to the right in FIG. 4 from fully extended toward re- 1 tracted positions.

Here it is again noted that for advancing the quill 57, the piston 47 is moved on its retracted direction, to the right in FIG. 4, thus moving the rack 49 and cam bar 60 to the right. It is also to be noted that as the piston is retracted, in FIG. 4, the memory dog 62 is carried to the right by and with the cam bar 60 until the finger of the dog 62 strikes the pin 71, whereupon movement of the dog 62 is arrested while the cam bar 60 continues to move to the right. The piston 47 is extended to the left in FIG. 4 to retract the quill 57, for removing chips from a bore being drilled before making the next successive drilling cut. Upon the subsequent retraction of the piston to advance the quill 57, the quill will be advanced rapidly to a new position, determined by the new position of thedog 62, for starting the next successive cut, and then will be fed at a slower rate during cutting. The successive positions of the memory dog 62 and certain limit switches and control elements to be described hereinafter assure the proper successive starting positions of the drill, when the bore being drilled is so deep that it must be drilled progressively deeper by a succession of increments of feed each of which is followed by complete withdrawal of the drill to remove chips.

Generally, as indicated in FIG. 7, the control is arranged so that each rapid advance of the quill ceases when the drill point has closely approached, but has not reached, the surface of the work on the first step, or the bottom of each partially drilled bore produced by a preceding feed step after the first step, and is followed by a slower cutting feed beginning just before the drill point finally engages the bottom of the partially drilled bore. This prevents jamming of the drill by too rapid an advance as it starts a cutting operation.

Mounted on the panel 42 are limit switches LS1, LS2, and LS3, respectively. A limit switch LS4 is adjustably mounted on the drill press and is operated by the quill 57, when the quill is fully advanced to the full final depth of cut, in the single cut cycle or the final cut of the successive cut cycle.

Also mounted on the panel 42 in parallel relation to the path of the cam bar 60 is a rock bar 75 which is supported by suitable brackets 76 for rocking movement about its axis and for limited movement endwise. The rock bar 75 carries a reset finger 77 for resetting of the memory dog 62 to its original starting position after a complete cycle. The bar 75 also carries a trip 78 which in the normal unrocked position of the bar is arranged to be engaged by the trip pin 69 for causing the rock bar to actuate the limit switch LS2 for terminating the return of the quill 57 when the tool point has been withdrawn just beyond the surface of the workpiece. The rock bar 75 is biased to the right in FIG. 4 by means of a coil spring 79. The reset finger 77 and trip 78 are adjustable individually endwise of the rock bar 75, by sliding them along the bar 75 to selected adjusted positions, and securing them in the selected positions by conventional set screws, not shown.

As the quill 57 starts to return from cutting position, the cam bar 60 is driven to the left and the rock bar 75 is in a normal unrocked position in which the trip 78 is in a position to be struck by the pin 69 and the reset finger 77 is out of the path of the dog 62. Accordingly, upon initiation of each of the successive cutting steps after the first one, the dog 62 remains in the position on the cam bar 60 to which it was caused to be moved by the pin 71 during the preceding feed step.

When the pin 69 strikes the trip 78, it drives the rock bar 75 to the left, closing the switch LS2, which stops the return of the quill 57 with the drill point withdrawn from the bore it has cut to a location just beyond the work surface. Concurrently, the closure of the switch LS2 restarts the rapid advance of the quill, the termination of which and the start of feed are controlled by the dog 62 and the switch LS3. The difference in the distance between the pin 71 and the position of the limit switch LS3 relative to the position of the dog 62 is chosen so as to stop the rapid advance of the quill 57 at a location short of the workpiece so that the drill assumes its slower feed advance before striking the work.

Thus, the termination of the original rapid advance and the start of the feed are controlled by the coaction of the dog 62 and the switch LS3, as are the termination of the rapid advance and the start of feed for each successive cut of the cycle. The different position of the quill at which each successive feed is started in successive cutting cycles is determined by the new position to which dog 62 has been moved by the pin 71 upon the termination of the immediately preceding cut.

Upon rocking the rock bar 75 to its rocked. position, the reset finger 77 is moved into the path of the memory'dog 62 and arrests its movement to the left with the cam bar 60 so that the dog 62 is restored to its original starting position when the quill 57 reaches fully returned position.

For thus restoring the dog 62 in its initial starting position for the next cycle during the final return of the quill 57, the bar 75 is rocked by a linkage 80, driven by a solenoid 81 which is controlled bya control relay, to a positionto place the reset finger 77 in the path of the dog 62 while moving the trip 78 out of the path of the trip pin 69, thus overriding the switch LS2.

After thus restoring the dog 62, to its original position, the rock bar 75 remains in its rocked position with the trip 78 out of the path of the pin 69 so that the rack 49 continues moving to the left in FIG. 4, until it operates the switch LSI and thereby stops the entire operation with the quill restored to its original starting position for a repeat cycle.

Before describing the electric and hydraulic circuitry in detail, it is well to review the functions of the limit switches.

The limit switch LS1 is'in a position to be engaged I and operated by the free or left hand end of the rack The limit switch LS4, as mentioned, is operated by the quill 57 itself, when the quill is fully advanced, to start the full return of the quill to its original starting position.

The limit switch LS3 is operated by the dog 62 as the dog is carried to the right by the cam bar 69, thus terminating the rapid advance of the quill and starting the dwell and slower feed advance.

HYDRAULIC ClRCUIT The hydraulic circuit employed in the control is shown schematically in FIG. 5. Forprecise operation, it includes the restrictive flow regulating valve V hereinbefore described in detail.

In this hydraulic circuit, the piston and cylinder assemblage is reversible. The pipeline 59 is connected to the head end of the cylinder 45 and the pipeline 58 to the rod end.

The pressure fluid is supplied by a variable delivery, pressure compensated pump P driven by a motor M. The output of the pump is delivered through a line 82 to a normally closed solenoid operated hydraulic stop and reversing valve 83. The valve 83 is reversible selectively by an advance solenoid 83a and a return solenoid 83b. A return line 84 leads from the valve 83 to a sump S. Leading from the reversible discharge and return ports of the valve 83 are

lines

85 and 86, respectively. The line 85 is connected to the inlet of a check valve 87, the outlet of which is connected to the line 58, and thereby to the rod end of the cylinder 45. The outlet of the valve 87 is also connected to the inlet 88a of a regenerating circuit valve 88 having an inlet 8821, an outlet 88b, and a plug 89 which is normally spring seated to close the inlet 88a, but which can be unseated by a predetermined positive differential in pressure at the inlet 88a. The valve 88 is connected by a line 90 to the line 85 in by-passing relation to the check valve 87 so that the plug 89 is subjected to full line pressure or is vented to the sump S, depending upon the setting of the valve 83. The end of the plug 89 subjected to fluid from the line 90 is larger than the seatingarea of its opposite end which normally closes the inlet 88a.

When the solenoid 83a is energized, the valve 83 connects the pressure side of the pump P to the line 85 and the sump S to line 86. With this setting, the valve 88 is closed due to its biasing spring and the full line pressure delivered through the by-pass line 90. Concurrently, live fluid is delivered to the rod end of the cylinder 45 and return fluid is returned from the head end of the cylinder 45 to the sump S. This return is through the

lines

59 and 86 and, selectively, by way of the restrictive flowvalve V and a normally open solenoid operated valve 91 augmented by a limited small concurrent flow through the valve V.

The valve 91 is normally open and is closed by energization of a solenoid 9.10 to constrain all of the return flow to pass through the valve V which has its inlet 2 connected to the line 59 and its outlet connected to the line 86.

With the valve 91 open and the solenoid 83a energized, the piston 47 is driven to the right, advancing the quill rapidly, until the rapid advance is interrupted, by closure or reversal of the valve 83, or bottoming of the piston 47 in the head end of the cylinder 45, or closure of the valve 9.1 by energization of its solenoid 91c.

Generally, this rapid advance is terminated and the feed initiated by energization of the solenoid 91c, the valve 91 thereupon being set to block the return flow therethrough so that all of the return flow must pass initially through the restrictive flow valve V by which the return flow is retricted and controlled. Thus, with a relatively free return flow through the valve 91, rapid advance of the quill to feed starting positions is effected, and upon closing of the valve 91 by energization of its solenoid 91c, the rapid advance is terminated and slower advance of the quill for feed is effected by the valve V.

Starting with the valve 83 in OFF position, the operation is initiated by energization of the advance solenoid 83a so that the valve 83 connects the line 82 to the line 85, whereupon pressure fluid is supplied through the check valve 87 to the rod end of the cylinder 45 to drive the piston 47 to the right for rapid advance of the quill. Concurrently the valve 83 connects the head end of the cylinder 45 to the sump S primarily through the normally open valve 91 which by-passes most of the return fluid around the restrictive flow control valve V. To initiate the slower advance or feed of the drill, the valve 91 is closed by energization of the solenoid 910. While the solenoids 83a and 910 are energized, the rate of feed of the tool is controlled by the rate of discharge from the head end of the cylinder 45 permitted by the restricted flow valve V. Any tendency toward acceleration of the piston 47 to the head end of the cylinder which would result in an increased return flow of fluid through the valve V and acceleration of the quill feed, causes the spool 30 to move against the force of its biasing spring 31 and reduce the effective size of the orifice 37, thereby constraining the piston and quill from acceleration and assuring constant feed speed.

If, at the completion of the feed stroke, the solenoid 83a is deenergized, the valve 83 returns to its normally closed position in which all flow to the rod end of the cylinder 45 from the pump P and the return to the sump S are stopped. The electric circuit is arranged to provide for dwell in any stopped position.

If the return solenoid 83b is then energized, the valve 83 is operated to reverse the flow of pressure fluid therethrough. If the solenoid 91 is then deenergized, the valve 91 returns to its open position. Upon this energization of the return solenoid 83b and reversal of the valve 83, the line 86 is connected to the pressure side of the pump P and the line 85 is connected to the sump S. The flow from the pump P is then to the head end of the cylinder 45, a slight flow passing through the valve V and the main flow through the valve 91. The check valve 87 is seated to prevent return of fluid from the rod end of the cylinder 45.

Consequently, the return flow from the rod end of the cylinder 45 is through the line 58, to the inlet of the valve 88, thus unseating the plug 89 and connecting the line 58 to the inlet of the valve 91 and to the outlet of the valve V, and both the valve V and valve 91 are connected by the line 59 to the head end of the cylinder 45. Since the valve 91 is now open, the rod end of the cylinder 45 is connected to the head end. As a result, pressure fluid from the pump P and return fluid from the rod end of the cylinder 45 are commingled and fed to the head end of the cylinder, and both ends of the cylinder are subjected to substantially the same fluid pressure. The rod 48 is of sufflcient diameter so that the total pressure exerted on the head end of the piston 47 is greater than the total pressure exerted on the rod end. This positive differential in pressure on the head end drives the piston 47 to the left, thereby driving the quill 57 on its rapid return stroke, which stroke requires but little power. The circuit is, therefore, regenerative, and a much more rapid operation of the piston is obtained than would be possible with a like pump delivery were the return fluid from the rod end of the cylinder returned to the sump S.

Thus the adjustment of the position of the valve plug 20 determines the rate of flow through the restricted flow regulating valve V, and hence the rate of return flow from the head end of the cylinder 45, and thereby the rate of advance of the quill.

ELECTRICAL CONTROL CIRCUIT A schematic wiring diagram, shown in FIG. 6, is used to control the sequence of operations to provide the selected steps of the cycles desired. Its functioning is best understood by a description of it in connection with the cycles of operation.

SINGLE CUT CYCLE WITH FULL RETURN For initiating this operation, a normally open pushbutton PB is closed, thereby establishing the following circuits:

a. through the normally closed contact 2CR1 of a control relay 2CR, the normally closed contacts TR2a of a timing relay TR2 and the coil of a control relay 1CR, thus closing the normally open contacts 1CR1 to provide a holding circuit around the pushbutton PB, and opening the normally closed contacts 1CR2 and closing the normally open contacts 1CR3 of the control relay lCR; and

b. through the contacts LS4(1) of the limit switch LS4 for energizing the advance solenoid 83a and thereby setting the valve 83 for advance of the quill 57, the solenoid 83a being maintained in energized condition through the holding circuit. Thereupon, live fluid is supplied to the rod end of the cylinder 45.

Since the valve 91 is open to vent the return fluid free to the sump S, the quill 57 is advanced rapidly toward its feed starting position in which the drill will be close to the surface of the work. This position is predetermined by the dog 62 engaging and closing the limit switch LS3. During this entire single cut cycle the normally open limit switch LS2 remains open.

When the dog 62 closes the switch LS3, the solenoid 91s of the feed valve 91 is energized and closes the valve 91, thereby directing all of the return flow from the head end of the cylinder 45 through the restrictive flow valve V and consequently stopping the rapid advance of the quill 57 and cbncurrenty initiating the slower cutting feed of the quill. The rate of cutting feed is determined by the rate of this return flow.

The closure of the limit switch LS3 also energizes the coil of a timing relay TR1 which starts the cutting time. For a single cut cycle, this timer is preset for a longer time than that required for the full cut and consequently it does not time out during the cycle. It therefore performs no timing function for a single cut cycle, but remains energized until deenergized by opening the limit switch LS3.

However, until the timing relay TR1 times out, its normally closed contacts TRla and TRlb remain closed. The closed contacts TRla establish a holding circuit by-passing the normally closed contacts 2CR1 of a control relay 2CR so as to maintain the coil of the relay lCR energized when the contacts 2CRl subsequently open. The contacts TR16 establish a circuit through the now closed contacts 1CR3, the normally closed contacts TR2b of a timing relay TR2, to energize the coil of the control relay 2CR.

Energization of the coil of the relay 2CR (a) opens its normally closed contacts 2CR (l) which leaves control of the energization and deenergization of the control relay lCR to the normally open contacts LS4(2) of the limit switch LS4, the normally closed contacts TRla, and the normally closed contacts TRZa of the timing relay TR2; and (b) open its normally closed contacts 2CR2 so as to prevent energization of the override solenoid 81 through the normally closed limit switch LS1. This eliminates rocking of the rock bar 75 while the limit switch LS1 is closed so that the pin 69 cannot strike the trip 78 and operate the limit switch LS2.

As the quill 57 is advanced on its cutting or feed stroke, it causes the limit switch LS4 to operate its contacts LS4(1) so as (a) to deenergize the advance solenoid 83a, thereby stopping advance of the quill 57, (b) to start the timing relay TR2 which starts a dwell time at the end of the feed stroke, and (c) to cause the contacts LS4(2) to close and establish a holding circuit for the coil of the control relay lCR through the contacts TRZa so that th control relay lCR remains energized Though the limit switch LS1 remains closed, the contacts lCR(2) remain open, so the solenoid 83a remains deenergized.

At the timed dwell period, the timing relay TRZ times out, opening temporarily its normally closed contacts TR2a, thereby deenergizing the coil of the control relay lCR whereupon its normally open contacts lCRl reopen to break the holding circuit around the normally open pushbutton PB.

Since limit switch LS2 has been overridden, it has remained in its normally open condition and consequently has not established a holding circuit around the push button PB.

Concurrently with the temporary opening of its normally closed contacts TR2a, the timing relay TR2 opens temporarily its normally closed contacts TRZb, deenergizing the coil of the control relay ZCR.

Deenergization of the coil of control relay 2CR recloses its normally closed contacts 2CR1, thus restores the by-pass around contacts TRla and recloses its normally closed contacts 2CR2 to reconnect the solenoid 81 for energization to rock the bar 75 to position the trip 78 out of the path of the pin 69 so as to override the operation of the limit switch LS2, and reopens its normally open contacts 2CR3 to open the holding circuit around the contacts 1CR3 to open the holding circuit around the contacts 1CR3 and TRlb, to the normally closed contact TR2b and the coil of the control relay 2CR.

The coil of the control relay lCR remains energized so that its normally closed contacts 1CR2 are held open. Concurrently the return solenoid 83b cannot be energized. When the coil of the control relay lCR is deenergized by opening of the contacts TR2a temporarily after dwell, its now open contacts 1CR2 reclose. Since the limit switch LS1 is closed, reclosure of the contacts 1CR2 energizes the return solenoid 83b, extending the piston 47 to the left to drive the quill 57 on its return stroke.

The return of the quill 57 continues until the rack 49, moving to the left in FIG. 4, strikes and opens the limit switch LS1 and deenergizes the return solenoid 83b. At this time the quill 57 is fully returned to its original starting position.

Since the by-pass circuit around the pushbutton PB is open, the opening of the limit switch LS1 terminates the single cut cycle which can be restarted only by closing the pushbutton PB.

Since the timing relay TRI was timed for a period longer than a one cut cycle, the normally closed contacts TRla remain closed and the normally open contacts TRlb remain open. The normally closed contacts TR2a, which were opened temporarily by the timing relay TR2 have reclosed. The circuitry is therefore in readiness to restart the cycle on closure of the pushbutton PB.

It is to be noted that during the cut, the dog 62, after striking the pin 71, was prevented from moving to the right in FIG. 4 with the bar 60. However, during movement of the bar 60 to the left during retraction of the quill 57, the bar was rocked by the solenoid 81, due to reclosing of the normally closed contact 2CR2, to move the reset 77 into the path of the dog 62 with the bar 60 and thus restores the dog to its original starting position on the bar 60 so that the next rapid advance from fully returned position of the quill 57 will be terminated and the single feed step begun with the drill point at the original feed starting point close to, but not in contact with, the work surface.

MULTI-STEP CYCLE WITH SUCCESSIVE PROGRESSIVELY DEEPER CUTS WITH RETRACTION OF TOOL FROM WORKPIECE FOR CHIP REMOVAL AFTER EACH FEED STEP In this cycle, the quill 57 is advanced rapidly to bring the drill point close to the original work surface, and the feed is then initiated, in the same manner as in the case of the single cut cycle.

However, the timing relay TR] is set for a timing interval for a fraction only of the complete cut so that the quill, after the drill has penetrated the work for a preselected depth, is returned rapidly until its point is slightly out of the bore, but near the original work surface, thus removing the chips. Upon reaching this location, a rapid advance step is started and continues until the drill point is close to, but spaced from, the bottom of the portion of the bore drilled in the preceding step. Thereupon the feed is initiated and the bore is drilled more deeply, followed by a dwell and then return of the drill point to the same position slightly out of the bore.

These successive steps are continued until the bore is drilled to the full depth whereupon the quill is returned fully to its original starting position.

These steps are indicated specifically in FIG. 7.

At the end of the first cutting step, when the drill has cut the preselected depth, the timing relay TRl times out, (a) tempoarily opening its contacts TRla; (b) and temporarily closing its normally open contacts TRlb. The coil of the control relay lCR remains energized through the normally closed contacts 2CR1 and now closed contacts TR2a, so as (a) to retain normally open contacts lCR(l) closed to establish the holding circuit around the pushbottom PB, (b) to retain the normally closed contacts lCR(Z) open so that the return solenoid 83b remains deenergized; and (c) to retain the normally open contacts LCR3 closed to establish a circuit through the closed contacts TRlb and tr2b and the control relay 2CR. This energizes the coil of the control relay 2CR, (a) closing its contacts 2CR3 to establish a holding circuit by-passing the contacts 1CR3 and TRlb;

b. opening the normally closed contacts 2CR2 so that the solenoid 81 is deenergized and the rock bar 75 is unrocked; and

c. opening its normally closed contacts 2CR1.

Since the timing contact TRla is open, as also is the limit switch contact LS4(2), the opening of the contacts 2CR1 deenergizes the control relay lCR, whereupon its normally closed contacts lCR2 are closed. Therefore, the return solenoid 83b is energized and the quill 57 is driven on its return stroke.

Since the rock bar 75 is unrocked, the trip 78 remains in the path of the pin 69. Accordingly, the return continues until the pin 69 strikes the trip 78, driving the rock bar 75 to the left and closing the normally open limit switch LS2. Closure of the limit switch LS2 reenergizes control relay 1CR through the normally closed contacts 2CR1 and the closed contacts TR2a. This immediately opens the normally closed contacts 1CR2 to deenergize the return solenoid 83b and closes the normally open LS3, energizing the solenoid 910 to set the feed valve 91 to start the feed.

Here it is to be noted that the dog 62 has not been restrained from movement with the bar 60 to the left during the previous return stroke, and hence remained in the position on the bar 60 to which it had been moved by the pin 71 during the preceding feed stroke. Therefore, it does not trip the limit switch LS3 and start the feed until the drill point has advanced almost to the bottom of the portion of the bore cut by the preceding cut, as the dog was driven to the left relative to the bar 60 to this position of the quill on the first cut. Upon closure of limit switch LS3 the timing relay TRl is again energized.

The feed continues, as with the first cut, until the next depth of cut selected has been reached and the timing relay TRl has timed out again. Meanwhile, as

before, since at the end of the return of the quill 57 c after the preceding cut, the limit switch LS2 had been closed and the control relay lCR energized by way of the contacts 2CR1 and contacts TR2a. This again establishes the holding circuit through contacts lCRl and opens the circuit through LCR2 to the return solenoid 83b to stop the return and energizes the advance solenoid to restart the rapid advance of the quill.

This succession of cuts is repeated until the limit switch LS4 is operated to energize timing relay TR for timing dwell and stop, and to establish a holding circuit to the control relay lCR until the timing relay TR2 times out andopens the contacts TRZa and deenergizes the control relay lCR. Thereby the normally closed contact 1CR2 closes, again energizing the return solenoid 83b to return the quill. When the timing relay TR2 times out, both control relays lCR and 2CR are deenergized, so the return solenoid 83b remains energized until the rack 49 opens limit switch LS1 and stops the cycle with the quill 57 in fully returned position. The repetitive incremental cycle is restarted by closure of the pushbutton PB.

As mentioned, cyclic controls for machines generally are mounted in floor supported cabinets which require detachment and partial disassemblage for removal from the machine if the machine is to be moved to a different work site.

In the present instance the support 40 is connected to a bracket 92 which, in turn, is bolted in fixed position on the frame or housing of the drill press.

The bracket 92 together with the housing of the shaft 51 of the pinion 50 and shaft 53 of the press, support the entire control as a unitary part of the whole so that the press can be moved to different work sites without disturbing the control Having thus described my invention, I claim:

1. A restrictive flow regulating and control valve mechanism comprising a hollow body having a first bore and a coaxial second bore, said body having an internal annular shoulder at the juncture of said bores and with an end face facing toward the outer end of said first bore and normal to the axis thereof;

said first bore having an inlet and said second bore having an outlet;

a seat member in the first bore, and having a flow passage therethrough, a portion of said passage having a cylindrical wall with its axis parallel to the common axis of the bores;

said seat member having an external radial annular flange coaxial with the cylindrical wall and of less diameter than said first bore, one end of the flange facing toward, and being engageable with, said shoulder and the other end of the flange facing toward the outer end of said first bore, the end faces of the flange being parallel to each other and normal to the axis of the cylindrical wall;

a header plug mounted in and closing the outer end of said first bore and adjustable to different positions axially thereof, and having a central axial stem receiving bore;

a valve plug member in the first bore and cooperable with the seat member for controlling the flow through the flow passage and having a cylindrical portion interfitting precisely in coaxial slip-fitting sealing relation with said cylindrical wall when the valve plug and seat members are in installed condition in the body;

a stem on the valve plug member mounted in said central axial bore for axial movement relative to said header plug and to said seat member;

clamping means in said first bore and movable with said header plug axially of said first bore to predetermined axially adjusted positions, and having an inner end portion aligned axially of the bores with said flange, which inner end portion, in one of said axially adjusted positions, is disposed close to, but slightly spaced axially from, said opposite end of the flange while said one end of the flange rests on said shoulder, thereby to hold the seat member in the first bore for limited movement relative to the body radially of the axis of said bores so that the seat member can be shifted radially to permit precise coaxial relation of its cylindrical wall with said cylindrical portion of the valve plug member by introduction of the cylindrical portion of the valve plug member thereinto;

said clamping means being operative, when moved additionally toward said shoulder, to engage said opposite end face of the flange and clamp the flange in sealing relation against said shoulder in fixed axial and radial position relative to said bores while the cylindrical portion of the valve plug member is in said precise interfitting coaxial relation with said cylindrical wall of said seat member; said cylindrical portion of the valve plug member having passage means therein connecting the bores and provided with inlet means which are open through the outer circumferential wall of said cylindrical portion and positioned so that the inlet means are progressively decreased in effective size by said cylindrical wall as the cylindrical portion of the valve plug member is moved progressively farther axially in a direction toward said second bore; wherein said passage means and inlet means comprise an axial dead end bore in the cylindrical portion of the valve member and open at the inner end of the valve plug member, and at least one narrow radial slot extending lengthwise of the cylindrical portion for the major portion of the length of the cylindrical portion and extending radially through said cylindrical portion from the outer surface of the cylindrical portion into said dead end bore,

a piston in the second bore and reciprocable axially thereof, and operative as it is moved from a retracted position to an extended position axially of the second bore to progressively restrict said outlet;

a spring biasing the piston to said retracted position;

and

said body having a duct continuously connected with said inlet of the first bore and connected to the second bore at a location between the outer end of the second bore and outer end of the piston so as to subject the piston continuously to the fluid pressure at said inlet for variably biasing the piston thereby toward its extended position against the force of the spring in relation to inlet pressure.

UNI'HED STATES PATENT nwm:

CERTWIQATE 0F CORRECTION Patent No. 3,7 ,7 5 Dated D c mb r 5, 973

Inventor(s) Eugene E. Swatty It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Col. 2, line 52, for "liner" read --inner---. I

Col. 3, line 18, for "longitudinal" read --longitudinally--;

line 36, for "sealed" read --se.aling--.

Col. L, line 16, for cylindrival".read -cylindrical--.

Col. 6, line'l3, read --the piston 1+? is moved'in its retracting direction, to the. I

Col. 8, line 6, for numeral "69" read -60--.

Col. 9, line 6, for "retricted" read --restricted- Col. 11, line 3, for "T1216" read --TRlb--; line 28, for

"th" read --the--.

Signed and sealed this 12th day of November 1974.

(SEAL) Attest:

McCOY M. GIBSON JR. C. MARSHALL DANN Attesting Officer Commissioner of Patents )RM PO-105O (10-69) USCOMM-DC GOING-P69 h u s GOVVERNMINT rnmvmc OI'IICI ID. o-au-su

Claims

1. A restrictive flow regulating and control valve mechanism comprising a hollow body having a first bore and a coaxial second bore, said body having an internal annular shoulder at the juncture of said bores and with an end face facing toward The outer end of said first bore and normal to the axis thereof; said first bore having an inlet and said second bore having an outlet; a seat member in the first bore, and having a flow passage therethrough, a portion of said passage having a cylindrical wall with its axis parallel to the common axis of the bores; said seat member having an external radial annular flange coaxial with the cylindrical wall and of less diameter than said first bore, one end of the flange facing toward, and being engageable with, said shoulder and the other end of the flange facing toward the outer end of said first bore, the end faces of the flange being parallel to each other and normal to the axis of the cylindrical wall; a header plug mounted in and closing the outer end of said first bore and adjustable to different positions axially thereof, and having a central axial stem receiving bore; a valve plug member in the first bore and cooperable with the seat member for controlling the flow through the flow passage and having a cylindrical portion interfitting precisely in coaxial slip-fitting sealing relation with said cylindrical wall when the valve plug and seat members are in installed condition in the body; a stem on the valve plug member mounted in said central axial bore for axial movement relative to said header plug and to said seat member; clamping means in said first bore and movable with said header plug axially of said first bore to predetermined axially adjusted positions, and having an inner end portion aligned axially of the bores with said flange, which inner end portion, in one of said axially adjusted positions, is disposed close to, but slightly spaced axially from, said opposite end of the flange while said one end of the flange rests on said shoulder, thereby to hold the seat member in the first bore for limited movement relative to the body radially of the axis of said bores so that the seat member can be shifted radially to permit precise coaxial relation of its cylindrical wall with said cylindrical portion of the valve plug member by introduction of the cylindrical portion of the valve plug member thereinto; said clamping means being operative, when moved additionally toward said shoulder, to engage said opposite end face of the flange and clamp the flange in sealing relation against said shoulder in fixed axial and radial position relative to said bores while the cylindrical portion of the valve plug member is in said precise interfitting coaxial relation with said cylindrical wall of said seat member; said cylindrical portion of the valve plug member having passage means therein connecting the bores and provided with inlet means which are open through the outer circumferential wall of said cylindrical portion and positioned so that the inlet means are progressively decreased in effective size by said cylindrical wall as the cylindrical portion of the valve plug member is moved progressively farther axially in a direction toward said second bore; wherein said passage means and inlet means comprise an axial dead end bore in the cylindrical portion of the valve member and open at the inner end of the valve plug member, and at least one narrow radial slot extending lengthwise of the cylindrical portion for the major portion of the length of the cylindrical portion and extending radially through said cylindrical portion from the outer surface of the cylindrical portion into said dead end bore, a piston in the second bore and reciprocable axially thereof, and operative as it is moved from a retracted position to an extended position axially of the second bore to progressively restrict said outlet; a spring biasing the piston to said retracted position; and said body having a duct continuously connected with said inlet of the first bore and connected to the second bore at a location between the outer end of the second bore and outer end of the piston so as to subject the piston continuously to the fluid pressure at said Inlet for variably biasing the piston thereby toward its extended position against the force of the spring in relation to inlet pressure.