US1924138A

US1924138A - Control mechanism

Info

Publication number: US1924138A
Application number: US319868A
Authority: US
Inventors: Strawn Marion Llewllyn
Original assignee: Western Electric Co Inc
Current assignee: AT&T Corp
Priority date: 1928-11-16
Filing date: 1928-11-16
Publication date: 1933-08-29
Anticipated expiration: 1950-08-29

Description

Aug. 29, 1933- M. L. STRAWN 1,924,138

' CONTROL MECHANISM Filed Nov. 16. 1928 2 Sheets-She et 1 .98 fig. 97

Aug. 29, 1933. M, L. STRAWN CONTROL MECHANISM Filed Nov. 16, 1928 2 Sheets-Sheet 2 m ww M @w M w m V1 m mm W d w M W m m.

f) ar Patented Aug. 29, 1933 UNITED STATES PATENT OFFICE CONTROL MECHANISM Application November 16, 1928 Serial N0. 319,868

4 Claims. (01. 60-52) This invention relates to control mechanisms, and more particularly to a control mechanism for machine tools.

The primary object of this invention is to provide an improved mechanism for controlling various operations of machine tools.

In accordance with one embodiment of this invention as applied to a multiple spindle drill press having a reclprocatory head, there is provided an automatic inelastic pressure medium variable displacement pump mechanism of a commercial type for supplying an inelastic pressure medium to the drill head feed cylinders for producing variable speeds of advance and a return 15 movement of the drills carried by the head. The action of the pump is automatically controlled by actuation of a rotary multiple spring controlled valve and mechanisms connected to the valve and the springs are automatically controlled in the movement of the head by a plurality of adjustable cam members arranged on the head and engageable with the mechanisms in predetermined sequence to store energy in the springs and thereafter release them to actuate the valve. Retractable means is operatively associated with the valve which is operable to permit an actuation thereof for rendering the system effective to complete a cycle of movements of the drill head or upon being maintained in an actuated position to provide for continuous reciprocating movements of the drill head.

Other objects and advantages of this invention will more fully appear from the following detailed description, taken in connection with the accompanying drawings, wherein Fig. 1 is a fragmentary side view of a multiple spindle drill prifis in which one embodiment of the control mechanism of this invention is employed to control the reciprocation of the drill head, the press and the control mechanism being illustrated in partial diagrammatic form;

Fig. 2 is an enlarged fragmentary view of Fig. 1, partially in section;

Fig. 3 is a vertical section on the line 3-3 of Fi 2; 1

Fig. 4 is a detail fragmentary plan view of Fig. 2; and

Figs. 5 and 6 are elevations of a cam plate carried by the drill head showing different portions 53 of the adjustable cams carried thereby for automatically actuating the rotary valve for automatically controlling the action of the variable displacement pump.- Referring now to the drawings in detail wherein reference numerals indicate similar parts,

by The Oil Gear Company of Milwaukee, Wisparticularly Fig. 1, which illustrates a multiple spindle drill press of a well known type equipped with one embodiment of this invention, a vertical frame 10 is fragmentarily shown, upon which is supported for vertical reciprocation upon standards 11 fixed to the frame 10, only one of which is illustrated, a drill head 12 carrying a plurality of power driven drills 13. A work table 14 is fixed to the frame 10 below the drill head 12 to which is attached a holder 15 for the work to be drilled. The drills 13 may be rotated in any suitable manner, the details of which are not shown, since they are not believed necessary to a complete understanding of this invention. The drill head 12, referring particularly to Fig. 1, is reciprocated by an inelastic pressure medium, such as oil, acting through a pair of vertically arranged feed cylinders 18, only one of which is illustrated. Each of the cylinders 18 is provided with a piston 19 and a stem or rod 20 extending therefrom, the latter being fixed at their upper ends to lugs 21, only one of which is illustrated, formed upon the drill head 12, the cylinders being suitably attached to the frame 10.

In drilling operations with a press of the herein described type it is desirable to move the drill head 12 toward the work from its normal position at a high rate of speed, since this is merely an idle movement of the drills, and this movement for the sake of brevity will hereinafter be termed rapid approach movement. When the drills are about to engage the work the rate of speed is diminished, to be termed feeding movement #2, this speed varying with the nature of the material composing the work being drilled and the size of the drills. When the drills are about to complete their drilling operation, feeding movement #2 is changed to a still slower rate of speed, to be termed feeding movement #1, to prevent injury to the work when .the drills are about to break through-the'work and thereafter the direction of movement of the drill head is reversed, to be termed reverse movement and the head moves upwardly at a high rate of speed.

Oil is supplied to the cylinders 18 to cause reciprocation of the drill head 12 at variable speeds by a variable displacement pump 22 of a commercial type, known as an oil gear and manufactured consin, and inasmuch as the specific construction 05 of this pump forms no part of the present invention and is not considered necessary to a complete understanding thereof detailed illustration and description thereof is deemed unnecessary and therefore is illustrated diagrammatically in Fig. 1. A pump of this type is illustrated and described in Patent 1,854,127, issued April 12, 1932 to W. Ferris. The pump 22 is provided with two

oil conduits

25 and 26 connected to the upper and lower ends, respectively, of each of the cylinders 18. It will be apparent that upon oil being entered into the upper ends of the cylinders 18, under suitable pressure, by means of the conduit 25, the piston 19 with the attached drill head 12 will be moved downwardly and similarly when the oil is entered into the lower ends of the cylinders through the conduit 26, the pistons and the drill head will be moved upwardly, the speed of the drill head in either direction being governed by the rate of flow of the oil into the cylinders from the pump 22. It will be apparent that the

conduits

25 and 26 in addition to supplying oil alternately to opposite sides of the piston also serve alternately as conduits for returning the oil from above or below the piston 19 to the pump 22.

The action of the pump 22, that is, the direction and rate of flow of the oil therefrom and through the

conduits

25 and 26, is automatically controlled by the action of a rotary spring controlled valve 27 responsive to different positions of the drill head 12 by means to be hereinafter described, the valve being suitably supported from the frame 10. Referring particularly to Figs. 2 and 3, the valve 27 comprises a casing 28 provided with a bore 29 and a plurality of

ports

31, 32, 33, 34 and 35. Rotatably mounted in the bore 29 is a shouldered valve member 38 provided with a longitudinal axial bore 39 and a laterally extending bore 40 in an enlarged intermediate portion thereof, the enlarged portion fitting a corresponding portion of the bore 29 of the casing 28. The bore 40 communicates with the bore 3 9 and in the rotation of the valve member 38, to be hereinafter described, successively communicates with the

ports

31, 32, 33 and 34 of the casing 28. The

ports

31, 32, 33, 34 and 35 of the valve casing 28 are connected to the pump 22 by

conduits

41, 42, 43, 44 and 45, respectively. The bore 39 of the rotary valve member 38 is connected to a conduit 46 axially arranged therewith at its left end (Fig. 3), while its right end terminates within the radial bore 40. The pump 22 has an oil reservoir formed in its lower portion from which the oil under constant pressure is pumped through the outlet conduit 46 to the inlet port 39 of the rotary valve member 38. From the bore 40 communicating with the port 39 the oil is directed through either of the

ports

31, 32, 33 and 34, re-

spectively, and to a mechanism included in the pump 22 for determining the direction and volume of oil to be delivered by the pump 22 to the feed cylinders 18, or as shown in Fig. 2, wherein the valve member 38 is in a neutral position with the port 40 out of communication with the other ports, the pump is idling, at which time the oil is by-passed through a suitable relief valve within the pump adapted to prevent the pressure in the bore 39 from exceeding a predetermined value. The

ports

31, 32, 33 and 34, when not in communication with the radial bore 40 of the valve member, communicate with a circumferential groove 138 of the valve member which is connected by the radial bore 140 to an axial bore 139 of the valve member. The bore 139 communicates through a radial bore 48 with a peripheral channel 47 formed in a reduced bearing portion of the valve member. The channel 47 and the bore 48, it will be apparent, permit the flow of oil at all times from the bore 139 of the valve member into the exhaust port 35 of the casing 28, from which the oil is returned to the pump by the conduit 45.

The pump 22 is so constructed that its oil displacing action through either of the

conduits

25 and 26 into the cylinders 18 is controlled by the return flow of oil to the pump through the

valve ports

31, 32, 33 and 34. Briefly described, a return flow of oil through port 31 to the pump results in an oil displacement by the pump through the conduit 25'to the upper ends of cylinders 18, which causes a rapid approach movement of the drill head. A return flow of oil through port 32 changes the oil displacement by the pump through the conduit 25 to the upper ends of the cylinders to decrease the speed of movement of the drill head to feeding movement #2. A return flow of oil through port 33 changes the oil displacement by the pump through the conduit 25 to the upper ends of the cylinders, whereby the speed of movement of the drill head is further decreased to feeding movement #1." A return flow of oil through port 34 results in an oil displacement by the pump through the conduit 26 to the lower ends of the cylinders, which causes a rapid return or reverse movement of the drill head.

Keyed to the rotatable valve member 38 at opposite reduced ends thereof and adjacent the inner faces of the casing 28 is a ratchet wheel 50 provided with four teeth spaced 90 apart. Independently rotatable upon the valve member 38 between each end face of the enlarged center portion thereof and the adjacent end face of the ratchet wheel 50 is a gear 51. Upon a reduced axial portion 52 extending from the side face of each gear 51 adjacent the ratchet wheel 50 there is provided a radially extending bracket 53 pivotally supporting a spring retracted pawl 54 arranged to cooperate with the teeth of the ratchet wheel 50 in the operation of the control mechanism to cause indexing movements of the ratchet wheels 50 and thereby subjecting the valve member 38 to intermittent rotary motions to align the port 40 successively with the

ports

31, 32, 33 and 34 of the valve casing 38. Slidably mounted in guideways 55 formed in the bottom wall of the casing 28 below each of the gears 51 are gear racks 58 which are constantly urged toward the right (Fig. 2) by compression springs 59 mounted between a wall of the casing and the racks.

Levers

60 and 61 are pivoted at 62 on the casing 28 which support rollers 63 upon their lower ends, the rollers engaging the right end faces of the gear racks 58. The upper ends of the

levers

60 and 61 are bifurcated and pivotally supported upon a common shaft 64 extending between the furcations of the lever 60 is a horizontal link 65 and a trigger member 66. Referring particularly to Fig. 4, between the furcations of the lever 61 is pivotally supported a bifurcated end of a link 67 and pivoted to the furcations of the latter are trigger

members

68 and 69, the link 67 and the

trigger members

68 and 69 being pivoted on a common shaft '70.

Tension springs '72 and '73 attached to the underside of the

triggers

66 and 68, respectively, tend to rock them clockwise and thus maintain the triggers in their normal position (Fig. 2) with similar faces '74 thereof abutting similar stop faces 76 provided on the

links

65 and 67. Mounted around the shaft between opposite faces of the

trigger members

68 and 69 is a torsion spring 80 (Fig. 4) having one end attached to the shaft and its opposite end extending under the trigger member 69, the spring tending to rock the trigger counterclockwise and thus maintain the trigger in its normal position (Fig. 2) with a face 81 abutting a second stop face 82 provided on the link 6'7. The links 65 and 6'7 are pivoted at their left ends (Fig.2) to arms 83 and 84 respectively, in turn pivoted at 8'7 upon the casing 28. Tension springs 88 and 89 secured at one end to the

links

65 and 67, respectively, and at their opposite ends to a pin 90 mounted in a wall of the casing 28 constantly tend to move the links 65 and 6'7 with the trigger members 66,

68 and 69 carried thereby to the right (Fig. 2),

the

levers

60 and 61 being urged clockwise about their pivot 62. The tension of the

springs

88 and 89 normally is such that due to the rollers 63 carried at the lower end of the

levers

60 and 61 pressing on the racks 58, the ,force of the compression springs 59 is overcome and thus energy is stored therein, which in the operation of the control mechanism is released at predetermined intervals, as will be more fully described hereinafter, to slide the gear racks 58 to the right (Fig. 2), thus rotating the gears 51 counterclockwise and carrying the pawls 54 therewith.

Fixed to the rear face of the drill head 12, or as viewed in Fig. 2 at the left portion thereof, is a plate 93 having a plurality of vertical slots 94 within which are adjustably secured a plurality of

cams

95, 96, 9'7 and 98 (Fig. 5), serving in the reciprocation of the drill head to actuate the previously described pawl and ratchet mechanisms and thereby the valve 27 at predetermined intervals to vary the oil displacing action of the pump 22. The lower face of the cam 95 is horizontal and in a downward movement of the head 12 from the normal position shown in the drawings engages a similar face of the trigger 69 and idly passes thereby, merely rocking it downwardly against the action of the torsion spring 80, the trigger thereafter moving upwardly to its normal position. The upper face of the cam 95 is inclined and in an upward movement of the head 12 engages a similar face of the trigger 69, but as hereinbefore dsecribed, due to the cooperating faces 81 and 82 of the trigger 69 and the link 6'7, no relative movement of the trigger upon the link occurs and consequently the trigger and the link are pressed backwardly or to the left as viewed in Fig. 2, thus storing energy in the spring 89.

The other cams 96, 9'7 and 98 are all reversely mounted compared to the cam 95 so that their upper faces are horizontal and their lower faces inclined. Thus in the downward movement of the head 12 the inclined faces of the cams 96, 9'7 and 98 engage similar faces of

thetriggers

68 and 66 and due to the cooperating faces of the triggers and the

links

67 and 65, the latter are pressed backwardly and energy is thus stored in the

springs

89 and 88 at predetermined intervals in the downward movement of the head 12 in a manner similar to the storage of energy in the spring 89 during the upward movement of the head. During the upward movement of the head it will be apparent that the triggers'68 and 66 idly rock about their pivots againstthe action of the tension springs '73 and '72 as the cams 96, 9'7 and 98 pass thereby. Referring to Figs. 1 and 3, attached to one end of the valve member 38 projecting from the casing 28 is a stop arm 103 and movable into the path thereof is'an arm of a lever 104 pivoted upon the shaft 87, another 1 arm of the lever being pivoted to a downwardly extending link 105. The link 105, it will be apparent, may be connected to a foot treadle mechanism of, a type commonly employedin connection with the operation of machine tools. A tension spring 106 fixed to the lever 104 acts to return the lever to its normal position after being moved out of the path of the stop arm 103.

With the

cams

95, 96, 9'7 and 98 adjustably mounted upon the plate 93 (Fig. 5), which is reciprocable with the head 12 so as to produce the hereinbefore described cycle of movements of the latter, the operation of the press and the associated control mechanism is as follows: In a return of the mechanism to its normal position as shown in the drawings from a previous cycle of movements wherein during the reverse movement the trigger 69 and the link 6'7 had been moved backwardly by the cooperating cam 95, energy was stored in the spring 89 and as the cam passed the trigger the spring was released. Instead of the link 6'7 being permitted to move such a distance as to completely release the energy built up in the spring, the lever 104 which wasin the path of the 'stop' arm 103 carried by the valve member 38, the latter moving due to the energy of the spring 89, as will be more fully referred to hereinafter, engages the arm 103 and holds it with the port 40 of the member 38 midway between the

ports

31 and 34, thus stopping the head, the pump 22 idling. With the parts in this position it will be apparent that a downward movement of the link 105 will release the valve member 38 and it will immediately rotate clockwise due to the energy still stored in the spring 89 acting through the link 6'7, the lever 61, associated gear rack 58, gear 51, pawl 54 and ratchet 50, all

of which move clockwise and thus the port 40 is aligned with the port 31, the engagement of the left end of the gear rack with a stop surface 107 of the casing 28 serving to limit the movement of the parts to provide the desired alignment of the ports. link 67 carries the

triggers

69 and 68 to the right (Fig. 2) until they are in line with the end of the trigger 66, the end of the trigger 69 being indicated in dotted outline, while the trigger 68 at this time is directly behind the trigger 66. With the port 40 in communication with the port 31, which is connected to the pump 22 by the conduit 41, the oil displacing action of the pump is immediately changed to cause a large volume of oil to be displaced by the pump for admission to the upper ends of the feed cylinders 18 through the conduit 25 and thus a rapid approach movement" is effected of the drill head 12 towards the work.

This rate of movement of the drill head 12 continues, with the trigger 69 being pressed idly downwardly by the cam 95, as hereinbefore explained, until the cam 96 engages the trigger 68, which in the following manner rotates the valve member 38 clockwise 90 until the ports 40 and 32 are in communication. During the ,movement of the cam 96 past the trigger 68,

the link 6'7 is moved backwardly, storing energy in the cooperating spring 89, rocking the lever 61 counterclockwise, the cooperating rack 58 following the roller 63 of the lever towards the right, due to the energy stored in the cooper ating spring 59. This movement of the rack 58 rotates the cooperating gear 51 counterclockwise and thus the pawl 54 carried thereby moves 90 over the stationary ratchet ready to index the ratchet and valve member 38.- When the cam releases the trigger 68 the energy of the spring 89 is released, the link 6'7 moving quickly to the right (Fig. 2), rotating the lever 61 clock- This movement of the wise, the cooperating gear rack 58 moving to the left, storing energy in the associated spring 59. This latter movement of the gear rack 58, it will be apparent, moves the cooperating pawl 54 and the ratchet 50 90, thus moving the port 40 of the valve member 38 into communication with the port 32, which is connected to the pump 22 by the conduit 42, and the oil displacing action of the pump 22 will be immediately changed and consequently the volume of oil admitted to the upper ends of the feed cylinders 18 through the conduit 25 will be such that feeding movement #2 is effected of the drill head 12 during the greater part of the drilling operation. The releasing of the trigger 68,

as just described, which through the attached lever 67 resulted in the movement of the associated pawl 54 to index the cooperating ratchet 50 90 also indexed the other ratchet 50 cooperating with the pawl 54 connected to the lever 65 a like distance, since both ratchets 50 are fixed to the valv member 38. In the case of the pawl 54 connected to the lever 65 which was stationary at this time, the latter pawl is not indexed, its cooperating ratchet 50 merely moving idly therearound. From this description it will be apparent that when one of the pawls 54 is moving its cooperating ratchet 50 to index the valve member 90 the other pawl is idle; in other words, either pawl may be actuated to perform an indexing movement of the valve member 38, the other pawl being idle at this time.

The drill head 12 continues at this rate of movement until the descending cam 97 engages the trigger 66 and moves it backwardly in a manner similar to that described in connection with the same movement of the trigger 68 by the descending cam 96 and indexes the valve member 38 another 90, moving the port 40 into communication with the port 33, which is connected to the pump 22 by the conduit 43, the oil displacing action of the pump being immediately changed and thus feeding movement #1 is effected by the drill head 12 during the final drilling period. Upon completion of this last movement of the drill head 12 the oil displacing action of the pump 22 is changed to' cause a return movement of the head. This is accomplished by the descending cam 98 engaging the trigger 68, which with the cooperating link 67 is again moved backwardly as hereinbefore described in connection with the setting of the valve 27 for feeding movement #2 and through the cooperating pawl and ratchet mechanism the valve member 38 is again indexed 90. moving the port 40 into communication with the port 34, which is connected to the pump 22 by the conduit 44, and thus reverse movement is effected of the drill head 12 and it moves upwardly at a high rate of speed.

As mentioned at the beginning of this description of operation, a downward movement of the link 105 withdrew the lever 104 from the stop arm 103 carried by the valve member 38 and the drill head 12 began to operate through a complete cycle of movements as just described. It will be apparent that if the link 105 was released after its downward movement, the arm 104 will return to its normal position and into the path of the stop arm 103, due to the action of the spring 106. Thus, when the trigger 69 and the link 67 are moved backwardly, due to the upwardly moving cam 95 engaging the trigger, as hereinbefore described, and the trigger is released, the movement of the link 67 toward the right (Fig. 2) to index the valve member 38 under the action of the spring 89 another 90, the valve member is checked at the end of an indexing movement of 45 by the stop arm 103 engaging the arm 104 and the head 12 stops. In the case of the link 105, which has hereinbefore mentioned may be connected to a foot treadle mechanism, being held in its depressed operative position, either manually or,by a suitable latch mechanism (not shown), of a type usually employed in machine tools, so as to hold the arm 104 out of the path of the stop arm 103, it will be seen that at the end of the reverse movement of the head 12 as just described, the port 40 of the valve member 38 instead of stopping midway between the

ports

34 and 31 would have moved 90 to communicate with the port 31 and thereby automatic continuous operation of the head 12 would be effected, involving variable speeds of advance and a return movement thereof. The automatic continuous operation of a drill press in this manner is advantageous in some drilling machine operations wherein it is possible to use an automatic mechanism of either a reciprocable or a rotatable type for positioning the work, depending on the nature thereof, upon the work holder 14, in the interval of time during which the reverse movement and the subsequent rapid approach movement of the drill head take place.

In drilling some classes of work; for example, work having apertures of different diameters throughout their length, wherein in a previous drilling operation the larger diameter of the apertures had been drilled down, for convenience in describing say, to a point wherein the set=up illustrated in Fig. 5, the feeding movement #1 commences and thereafter in another operation the smaller diameter of the apertures is finished, the herein described and illustrated control mechanism may be used to advantage. In such a case it is desirable in order to expedite the drilling operation to omit feeding movement #2, the rapid transverse movement continuing down to feeding movement #1. This may be accomplished with the control mechanism herein described, referring to Fig. 6, by merely adjusting the cam 97 on the plate 93 to a suitable position above the cam. 96 as is clearly shown in the drawing, the two cams being in different vertical planes. With this arrangement of the

cams

96 and 97 it will be obvious that upon completion of the 90 indexing movement of the valve member 38 effected, in the manner previously described, by the downwardly moving cam 96 engaging the trigger 68 the cam 97 which is also moving downwardly and mounted a suitable distance above the cam '96 will engage the trigger 66 and cause the valve member 38 to be again indexed 90, thus effecting a substantially continuous indexing movement of 180 thereto. It is to be understood that the last mentioned indexing movement of 90 of the valve member 38 does not begin until after the cam 96 has completed the indexing of the valve member to align the port 40 thereof with the port 32 and then substantially at this inthe ports 32 and 33 could be passed over without an appreciable dwell of the port 40 thereat.

Although the control mechanism in the embodiment herein shown and illustrated is particularly adapted for inelastic pressure medium actuated reciprocatory drill press heads, it is not limited'to this use and may be adapted for a variety of other purposes and the invention is only to be limited by the spirit and scope of the appended claims.

What is claimed is:

1. A fluid pressure control mechanism comprising a casing having a plurality of fluid transmis-' sion ports, a valve member rotatablymovable therein to a plurality of operative positions for controlling said ports, and means for actuating and controlling the valve member comprising a reciprocable member for rotating the valve member from one to another of its operative positions, means operatively interconnecting the valve member and the reciprocable member to cause the valve member to be moved by the reciprocable member only during its movement in one direction, a second reciprocable member, and a spring controlled trigger mechanism actuated by the second reciprocable member at predetermined positions in its movement for effecting the intermittent reciprocation of the first reciprocable member at predetermined intervals.

2. A fluid pressure control mechanism comprising a casing having a plurality of fluid transmission ports, a valve member movable therein to a plurality of operative positions for controlling said ports, and means for actuating and controlling the valve member comprising a reciprocable member operatively connected to the valve member, a spring for moving the reciprocable member in one direction, a second spring opposing and normally overpowering the first spring, a stop opposing the action of the second spring, and

means for momentarily rendering the second spring inefiective to thereby cause a reciprocation of the reciprocable member.

3. A fluid pressure control mechanism comprising a casing having a plurality of fluid transmission ports, a valve member movable therein to a plurality of operative positions for controlling said ports, and means for actuating and controlling the valve member comprising a reciprocable member operatively connected to the valve member, a spring for moving the reciprocable member in one direction, a second spring opposing and normally overpowering the first spring, a stop opposing the action of the second spring, and means including a second'reciprocable member operative at a predetermined position in its movement for momentarily rendering the second spring inefiective to thereby cause a reciprocation reciprocable member.

4. A fluid pressure control mechanism comprising a casing having a plurality of fluid transmission ports, a valve member rotatably movable therein to a plurality of operative positions for controlling said ports, and means for actuating and controlling the valve member comprising a reciprocable member, a spring for moving the reciprocable member in one direction, a-second spring opposing and normally overpowering the first spring, a stop opposing the action of the second spring, means for momentarily rendering the second spring ineffective to thereby cause a reciprocation of the reciprocable member, and a pawl and ratchet mechanism responsive to the movement of the reciprocable member for rotating the valve member from one to another of its operative positions.

MARION LLEWLLYN STRAWN.

of the first