US3281995A

US3281995A - Machine tool

Info

Publication number: US3281995A
Application number: US332018A
Authority: US
Inventors: Alfred T Parrella; Gene R Gagliardi
Original assignee: Farrel Corp
Current assignee: Farrel Corp
Priority date: 1963-12-20
Filing date: 1963-12-20
Publication date: 1966-11-01
Anticipated expiration: 1983-11-01

Description

Nov. 1, 1966 PARRELLA ET AL 3,281,995

MACHINE TOOL Filed Dec. 20, 1963 1 5 Sheets-Sheet l HHved T. POWYO\ Gene R. Gaqhardi RMM De w ATTORNEY5 Nov. 1, 1966 Filed -Dec. 20, 1963 A- T. PARRELLA ET AL MACHINE TOOL 5 Sheets-Sheet 2 ENCODER COMPH RHTOR (B\-D\RECTIONF\L COUNTER) NUMBER TO FREQUENCY CONVERTER ENCODER DIG] THL TO PINQLOG CONVE RTER M H NUFH.

CONTROL HMPLIFlER INVENTORS Hlfied T Pavvdm Gene R Coaqharch RM M31 De w ATTORNEYS 1956 A. T. PARRELLA ET AL 3,281,995

MACHINE TOOL Filed Dec. 20, 1963 5 Sheets-Sheet 5 HLTERNRTING CURRENT/ 96 SOURCE LMJ P113 72 m BOWDISCRIMINHTOR DlSCRlMINRTOR, 9! l l COMPHRHTOR 95 HMPLIFIER 95 l l 4 MnNum. Z/ INVENTORS MOTOR CONTROL Hhved T. PoweHQ 3| Gene R Gaqhavch RM Ma De'iw ATTORNEY5 United States Patent 3,281,995 MACHINE TOOL Alfred T. Parrella, Newtown, and Gene R. Gagliardi,

Bethany, Conn, assignors to Farrel Corporation, Ansonia, Conn.

Filed Dec. 20, 1963, Ser. No. 332,018 17 Claims. (Cl. 51-165) This invention relates to machine tools and relates more particularly to machine tools having means for aligning a longitudinally extending workpiece with respect to a reference axis of the machine.

The invention may be employed to advantage in roll grinding machines and will, therefore, be dis-closed with reference to such a machine. A roll grinder in which this invention may be embodied is disclosed in US. Patent No. 3,088,250.

Over a period of time mill rolls used in steel mills for rolling steel will wear beyond permissible operating limits. This wear necessitates the regrinding of these rolls to provide the rolls with the surface characteristics necessary for proper operation of the rolls in steel mills. When a roll requires regrinding, it may be placed on a grinding machine such as that shown and described in the aforementioned patent with the axis of the roll substantially in parallelism with a reference axis of the machine, which reference axis is parallel to the path of travel of the grinding wheel of the machine. In practice it is seldom, if ever, possible to initially position a roll in the grinding machine in such a manner that its axis is within the desired degree of parallelism with a reference axis and the path of travel of the grinding wheel. The difiiculty in positioning a roll within the desired degree of parallelism is often due to uneven wear of the roll journals with respect to each other. This difficulty may also be due to the roll journal supports of the grinding machine not being properly positioned to align the axis of the roll with the path of travel of the grinding wheel.

This invention provides a new and improved machine of the character described which detects the center of each roll journal and the horizontal distance of each journal center with respect to a reference axis and actuates drive means to move one end of the roll together with the journal support in a direction and a sufficient distance so that there is no difference in the detected distances of the journal centers from the reference axis.

The invention provides new and improved means incorporated in a roll grinder, for example, adapted to be operatively positioned with respect to each roll journal to detect the center thereof, simultaneously measure the distance of each roll center from a reference axis, and provide an indication of any difference in such distances. The indication of such differences may be visually observed and corrective action initiated manually, or automatic means may be provided which is responsive to the detected error and operative to correct such error.

Accordingly, it is an object of this invention to provide a new and improved apparatus for detecting misalignment of a longitudinally extending workpiece with respect to a reference axis.

Another object of this invention is to provide a new and improved means in a roll grinding machine which detects misalignment of a roll thereon with respect to a reference axis, and is further effective to correct such misalignment.

A further object of this invention is to provide new and improved means for detecting the center of a cylindrical object and yielding an indication indicative of the distance of the detected center from a reference axis.

The features of the invention which are believed to be novel are pointed out with particularity and distinctly claimed in the concluding portion of this specification.

3,281,995 Patented Nov. 1, 1966 However, the invention both as to its organization and operation together with further objects and advantages thereof may best be appreciated by reference to the following detailed description -taken in conjunction with the drawings, in which:

FIG. 1 is plan view of a roll grinding machine which incorporates the invention;

FIG. 2 is a front elevation of machine in FIG. 1;

FIG. 3 is an end view of the illustration of FIGS. 1 and 2 as viewed from the right side;

FIG. 4 is a view similar to FIG. 3, but with certain parts shown in section;

FIG. 5 is a sectional view seen along line 5-5 of FIG. 4;

FIG. 6 is a view siimlar to FIG. 4 in illustrating roll jounal center detecting means, but illustrating an alternate embodiment thereof;

FIG. 7 is a diagram in block form of electrical measuring means for detecting differences in distance of the roll axis with respect to a reference axis, and prime mover means for aligning said axis;

FIG. 8 is a view similar to FIG. 4, which illustrates another embodiment of the invention; and

FIG. 9 is a diagram, partly schematic and partly in block form of electrical means for detecting and correcting misalignment of a roll axis using the measuring device shown in FIG. 6.

The invention may be embodied in a roll grinder generally indicated by the reference numeral 10 comprising a bed or frame 11 having thereon

ways

12 and 13, in turn having mounted thereon a grinding assembly 14 movable in either direction along the ways. The grinding assembly 14 includes a grinding wheel 15 adapted to operate upon a mill roll 16. Roll 16 is supported at each end thereof at

journals

17 and 18 on journal or neck supports 19 and 20, respectively.

Roll 16 is adapted to be turned on

supports

19 and 20 by a drive motor 21 through suitable gearing means 22. Journal 18 of roll 16 is suitably chucked to a head stock 23.

Means are provided on journal support 19 to move roll neck or journal 17 towards or away from grinding wheel 15 to properly align the axis of the roll with respect to the path of travel of grinding wheel 15.

Journal 17 is mounted on support 19 by means of bearings 25 and 26 (FIG. 3). Bearing 25 is mounted in the main body 27 of support 19 and bearing 26 is carried in an arm 28 pivotally mounted to body 27, as indicated at 29. Roll support body 27 is positionable along bed 30 on ways. Arm 28 is pivotal with respect to body 27 to allow adjustment of bearing 26 in a horizontal direction as viewed in FIGS. 3 and 4 and thereby allow horizontal adjustment of the axis of .roll 16.

Power drive means are provided to predetermine the position of arm 28. The drive means comprises a motor 31, carried on body 27, which drives a gear 32 through a pinion 33 on the motor shaft. Gear 32 drives a lead screw 34. Rotation of lead screw 34 produces upward or downward movement of nut 36 thereon dependent upon the direction of rotation of motor 31. Movement of nut 36 operates link 37. Link 37 is keyed to and operates to rotate eccentric shaft 38. Carried on shaft 38 is a pair of links 39 (only one shown) which are pivoted at the other end thereof to arm 28 at 41. Rotation of eccentric shaft 38 will produce rotative motion of arm 28 about ivot 29. This rotative motion of arm 28 causes neck support bearing 26 mounted in arm 28 to move inwardly or outwardly with respect to grinding wheel 15 to move journal 17 toward or away from the grinding wheel 15.

Extending upwardly from the body 27 of each journal support is an upright member 43 which comprises oppositely disposed

wall portions

44 and 45 extending above journal 17 a suficient distance for the purposes hereinafter described.

Wall portions

44 and 45 fixedly carry therebetween a shaft rotative means such as a fluid motor 47 secured to a cylindrical object center-detecting assembly 48. Assembly 48 comprises a member 49 having secured thereto fluid motor 47 to allow pivotal movement of assembly 48 about the axis of shaft 46. Mounted in and extending from member 49 are

parallel guide shafts

50 and 51 which slidably carry thereon a member 52 on bearing means 53. Member 52 carries a centering device which comprises a generally symmetrical U-shaped member 55 having

roller probes

56 and 57 at either end there of adapted to contact the surface of a cylindrical object, here shown as journal 17. Member 55 is vertically movable with respect to member 52 by means of a stem 58 slidably mounted in bearing means 59 carried by member 52. Biasing means shown as a spring 61 is provided between member 52 and member 55 to normally urge member 55 downwardly towards engagement with a cylindrical object.

Mounted in arm portion 63 of member 52 is a ball nut and screw assembly 64 comprising a nut 64a and screw thread 64b on shaft 65. Antifriction bearing elements in the form of balls are provided between the mating threads of the nut and screw to essentially eliminate friction therebetween. Shaft 65 is rotatably mounted in bearing means 66 on arm portion 67 of member 49 and coupled at 68 to the shaft of an encoder 69 carried on member 49 at 70.

With the construction disclosed, it may be seen that as member 52 moves on

guide rods

50 and 51, nut 64 will -have linear movement with respect to screw 64b and by .virtue of the ball connection therebetween such linear movement of nut 64a will produce rotation of shaft 65 proportional to the linear movement of nut 64a.

In the device shown in FIGS. 4 and 5, the roller probes 56 and 57 are symmetrically disposed on either side of the vetical center line of member 55, which coincides with the axis of stem 58. Therefore, when both of roller probes 56 and 57 are seated on the cylindrical surface of journal 17, the axes of the rollers are radially equidistant from the center of journal 17 and form equal angles with the center line through stem 58. At this time the center line of stem 58, which is the vertical center line of member 55 passes through the center of journal 17. The travel of member 52 on

guide rods

50 and 51 to properly seat probes 56 and 57 is a measure of the horizontal distance between the axis of shaft 46 and the center of journal 17. As hereinafter described,-the motion or rotation of shaft 65 is used to properly align the axis of roll 16 with respect to the axis of travel of grinding wheel 15. Stop ping means is provided in the form of a lug 43a on member 43 to engage the under surface of member 49, as viewed in FIG. 3, to maintain assembly 48 and guide

rods

50 and 51 horizontal when assembly 48 is rotated into operative position from the position show in broken line (FIG. 4).

FIGS. 3 and 4 illustrate a center locating device wherein the location of the center is signalled by rotation of shaft- 65. Shaft encoders 'which produce a digital or pulse output proportional to rotation of a shaft are well known to those skilled in the art and may be utilized in the present invention as hereinafter described.

FIG. 6 illustrates an alternate embodiment of the invention wherein the longitudinal movement of a member 50 is detected by a linear variable differential transformer 72. As well known to those skilled in the art, and hereinatfer exemplified in FIG. 9, a linear variable differential transformer is a transformer designed with two secondaries that are so arranged that at some position of a movable core, the output from each individual secondary is of equal amplitude and phase relation. The secon dary windings are connected in series opposition so that the outputs cancel. The secondary windings are distributed in such a manner that any physical displacement of the core causes the voltage in one secondary to increase while simultaneously reducing the voltage in the other secondary. The difference between the two voltages appears across the output terminals of the serially opposed secondaries and gives a measure of the physical position of the core. By detecting the magnitude of the output and the phase difference between the primary excitation voltage and the output voltage, linear movement of the core is detected. Such motion transducers are available from many sources, one of which is Daytronic Corporation of Dayton, Ohio, whose model 102B-160 linear variable differential transformer has been satisfactorily utilized in a structure exemplified in FIG. 6.

In utilizing the apparatus as shown in FIG. 4 a roll to be ground is first placed on the journal supports 19 and 20 and a centering assembly 48 on each of the journal supports is pivoted about its respective shaft 46 from the position shown in broken line in FIG. 4 to a position similar to that shown in full line in FIG. 4. It will be understood that initially member 52 is at its furthest degree of travel to the left as viewed in FIGS. 4 and 5. Then member 55 is urged downwardly towards journal 17 under the bias of spring 61 and roller probes 56 and 57 will seek the lowest possible location on journal 17. This lowest possible location occurs when both roller probes 56 and 57 have their axes equidistant from the center of roll 16. To assume such a position of member 55 it is necessary for member 52 to move to the right, as viewed in FIGS. 4 and'S, causing nut 64a to move along screw 64b. This in turn produces rotation of screw 64b in shaft 65 proportional to the linear distance travelled by nut 64. Rotation of shaft 65 in a preferred form of the invention causes encoder 69 to produce a plurality of pulses proportional in number to the linear movement of member 52. Therefore, the pulse output of encoder 69 is indicative of the horizontal distance between the axis of shaft 46 and the center of journal 17 In a similar manner, apparatus like that shown in FIGS. 4 and 5 is carried on roll support 20 and will yield the same information.

It will be understood that the axes of the shafts 46 on both of the journal supports coincide and such coincident axis is parallel to the path of travel of grinding wheel 15 along

ways

12 and 13. Therefore, any difference in the outputs of shaft encoder 69 on journal support 17 or shaft encoder 69', FIG; on journal 18 is indicative of the deviation in the axis of roll 16 with respect to the path of travel of grinding wheel 15. Such difference may be detected in a number of ways known to those skilled in the art. One exemplary way is to apply the pulse output of both of the shaft encoders to a comparator 75 (FIG. 7) in the form of a bidirectional counter to determine the difference. The error then appears as the resultant number in the counter. This number in the counter is then converted to a pulse frequency by number-to-frequency converter 76 and subsequently converted to a voltage by a digital-to-analogue converter 77. The votlage may then be read on a visual-indicating meter and the operator manually operates motor 31 to move journal 17 toward or away from grinding wheel 15 until the axis of roll 16 is parallel to the line of travel of grinding Wheel 15 and also the axis defined by shafts 46. At such time the visual-indicating meter 78 would show zero error. Alternatively, the number in the comparator 75 might be read directly by a suitable read-out means. In another alternative, the motor 31 may be automatically operated through an amplifier 79 which is sensitive to both the magnitude and the direction of the error. In this last mentioned arrangement the axis of the roll 16 would be automatically aligned with the reference axis. Automatic or manual control systems for eliminating any difference in the distance of the center of each journal from a reference point are known to those skilled in the art and various other systems and electrical components may be utilized.

It is to be understood that journal support 20, not illustrated in detail, supports journal 18 in a similar manner to that shown for journal 17. However, it is not necessary to provide means, such as arm 28, to move journal 18 toward and away from grinding wheel 15.

In the embodiment of the invention shown in FIGS. 4 and 5 the assembly 48 may be arranged to be pivoted about the pin 46 by means of the fluid motor 47. In another embodiment of the invention the center-detecting and signalling means are arranged to be raised and lowered by means such as a hydraulic cylinder. As exemplified in FIG. 8 a center-detecting means 80 and an indicating means, again in the form of a shaft encoder 81, are carried on an arm 82 which is mounted to a shaft 83 rotatably carried by a journal support member 84. Shaft 83 has a gear 85 thereon drivably engaged by a worm 86 driven by a motor 87, also mounted on journal support 84. The motor 88 is effective to rotate arm 82 on shaft 83 to aid in positioning centering assembly 80 011 roll journal 88. The centering assembly is movable vertically by means of a cylinder 89 which comprises arm 82.

In operation, the center-detecting means 80, together with the indicating means, is moved in a vertical direction towards or away from the roll journal 88 by means of cylinder 89 and when the center-detecting assembly and indicating means are not required motor 87 may be energized to move this assembly from the roll journal to a position as shown in broken line.

In FIG. 8 it may be seen that the structure of the detecting means 80 varies slightly from the structure of the detecting means shown in FIGS. 4 and 5. Likewise, the encoder carrier of FIG. 8 differs slightly from that of FIGS. 3, 4 and 5. However, the construction and operation of the apparatus of FIG. 8 will be apparent from the foregoing descriptions.

FIG. 9 illustrates another electrical measuring system using linear variable differential transformers 72 and 72' to measure the distances of the journal centers from a reference axis. Here the measured distances as detected in

discriminators

90 and 91 are compared in a comparator 92. The resultant error may be visually indicated on a meter 93 and a manual motor control 94 actuated to operated motor 31. Alternatively, an amplifier 95 may be utilized to sense the direction and magnitude of the error and operate motor 31 to nullify the measured error and thereby align the roll axis with respect to a reference axis. The

discriminators

90 and 91 compare the magnitudes and phases of the primary voltage of alternating current source 96 with the magnitudes and phases of the secondary votlages of transformers 72' and 72, respectively. The discriminators 9t and 91 then yield a signal indicative of movement of cores 72a and 722) respectively.

It may thus be seen that the objects of the invention set forth, as well as those made apparent from the preceding description are etficiently attained. Other embodiments of the invention as well as modifications to the disclosed embodiments of the invention may occur to those skilled in the art for practicing the invention. Accordingly, it is intended to cover in the appended claims all embodiments and modifications of the invention which do not depart from the spirit and scope of the invention.

What is claimed is:

1. In a machine tool of the type wherein a workpiece having generally cylindrical surfaces is supported at either end thereof and arranged to be axially aligned with a reference axis, the improvement comprising; means for detecting the center of a workpiece adjacent either end thereof, support means including guide means, said detecting means being movable on said guide means in a direction substantially perpendicular to the axis of a workpiece whose center is to be detected, and means responsive to movement of each of said detecting means for indicating the distances of the detected centers from a reference axis.

2. In a machine tool of the type wherein a workpiece having generally cylindrical surfaces is supported at either end thereof and arranged to be axially aligned with a reference axis, the improvement comprising; means the object until the difference is zero.

3. In a roll grinder of the type wherein a mill roll is supported on journal ends thereof on journal supports and arranged to be axially aligned with a reference axis, the improvement comprising; means for detecting the center of each journal at its journal support, support means including guide means, said detecting means being movable on said guide means in a direction substantially perpendicular to the axis of a mill roll supported on the grinder, and means responsive to movement of each of said detecting means for indicating the distance of the detected centers from a reference axis.

4. The apparatus of claim 3 further including means for moving one of the journal supports to eliminate any difference in the distance of the detected centers from the reference axis.

5. The apparatus of claim 3 including means for comparing the distances of the detected centers from the reference axis and means responsive to said comparing means for moving one of the journal supports to essentially eliminate the difference.

6. In a machine tool of the type wherein a workpiece having cylindrical surfaces is supported at either end thereof and arranged to be axially aligned with a reference axis and wherein means are provided for supporting the workpiece adjacent either end thereof, the improvement comprising; means for detecting the center of the workpiece adjacent either end thereof, means actuated by each of said detecting means for indicating the distance of the detected centers from a reference axis, means responsive to each of said indicating means for deriving a representation of the difference in the distance of the detected centers from the reference axis, and means responsive to the representation for moving one of the supports until the difference in the distance of the detected centers from the reference axis is zero.

7. A device for detecting the center of a cylindrical object comprising a member movable perpendicular to a reference axis, said member carrying thereon probe members arranged to engage a cylindrical surface on opposite sides of the center of the cylindrical surface, said probe members being symmetrically disposed with respect to a vertical center line and movable in a second direction perpendicular to the reference axis so that when said probes contact the cylindrical surface the vertical center line passes through the center of the cylindrical surface, and means for detecting the first perpendicular movement of said member to seat said probes on the cylindrical surface.

8. In a machine tool of the type wherein a workpiece is supported at either end thereof and arranged to be axially aligned with a reference axis and wherein means are provided for supporting the workpiece adjacent either end thereof, the improvement comprising; means for detecting the center of the workpiece adjacent either end thereof, means actuated by said detecting means for indicating the distance of the detected centers from a reference axis and means responsive to said indicating means for deriving a representation of the difference in the dis-.

tance of the detected centers from the reference axis.

9. The apparatus of claim 8 wherein said means for detecting comprises a member movable horizontally perpendicular to the reference axis, said member having thereon probe members arranged to engage a cylindrical surface, said probe members being symmetrically disposed with respect to a vertical center line so that when said probes contact the cylindrical surface the vertical center line passes through the center of the cylindrical surface.

10. The apparatus of claim 9 wherein said means for detecting is pivotally mounted on the machine tool for movement toward and away from the cylindrical surface.

11. In a roll grinder of the type wherein a mill roll is supported on journal ends thereof on journal supports and arranged to be axially aligned with a reference axis and wherein means are provided for supporting the workpiece adjacent either end thereof, the improvement comprising; first and second means for detecting the center of each journal, each of said means for detecting being pivotally mounted on the grinder about a common axis and each adjacent a journal so that said means for detecting may be pivoted into or away from engagement with an associated journal to allow a roll to be placed on and removed from the support, each of said detecing means being linearly movable substantially perpendicular to the axis of a mill roll to locate the center thereof, and means responsive to movement of each of said detecting means from a reference line to indicate the distance of said detecting means from said reference line.

12. The apparatus of claim 11 wherein said means for detecting comprises a member movable horizontally and perpendicular to the reference axis, said member having thereon probe members arranged to engage a cylindrical surface, said probe members being symmetrically disposed 'with respect to a vertical center line so that when said probes contact the cylindrical surface the vertical center line passes through the axis of the cylindrical surface.

13. A device for detecting the axis of a cylindrical object comprising means for supporting a cylindrical object, a probe member having depending probe arms symmetrically disposed on either side of a center line, said arms being adapted to engage the peripheral surface of a cylindrical object, a probe carrying member, a mounting member carried on said means for supporting a cylindrical object, guide means carried by said mounting member, said probe carrying member being movable on said guide means, biasing means interposed between said probe member and said probe carrying member urging said probe member away from said probe carrying member and toward an object whose center is to be detected so that when one of said probe arms contacts a cylindrical object, said biasing means acts to urge both said arms into engagement with the object on either side of the axis thereof and equidistant therefrom and said mounting member is moved on said guide means.

14. A device for detecting the axis of a cylindrical object comprising means for supporting a cylindrical object, a probe member having depending probe arms symmetrically disposed on either side of a center line, said arms being adapted to engage the peripheral surface of a cylindrical object, a probe carrying member, a mounting member carried on said means for supporting a cylindrical object, guide means carried by said mounting member, said probe carrying member being movable on said guide means, biasing means interposed between said probe member and said probe carrying member urging said probe member away from said probe carrying member and toward an object whose center is to be detected so that when one of said probe arms contacts a cylindrical object, said biasing means acts to urge both said arms into engagement with the object on either side of the axis thereof and equidistant therefrom and said mounting member is moved on said guide means, and means 8' for measuring the position of said probe means with respect tov a reference line.

15. A device for detecting the axis of a cylindrical object comprising means for supporting a cylindrical object, a probe member having depending probe arms symmetrically disposed on either side of a center line, said arms being adapted to engage the peripheral surface of a cylindrical object, a probe carrying member, a mounting member carried on said means for supporting a cylindrical object and including guide means, said probe carrying member being movable on said guide means, biasing means interposed between said probe member and said probe carrying member urging said probe member away from said probe carrying member and toward an object whose center is to be detected so that when one of said probe arms contacts a cylindrical object, said biasing means acts to urge both said arms into engagement with the object on either side of the axis thereof and equidistant therefrom and said mounting member is moved on said guide means, said mounting member being pivotally mounted to saidmeans for supporting a cylindrical object.

16. A device for detecting the axis of a cylindrical object comprising means for supporting a cylindrical object, a probe member having depending probe arms symmetrically disposed on either side of a center line, said arms being adapted to engage the peripheral surface of a cylindrical object, a probe carrying member, guide means carried by said means for supporting a cylindrical object, said probe carrying member being movable on said guide means, biasing means interposed between said probe member and said probe carrying member urging said probe member away from said probe carrying member and toward an object whose center is to be detected so that when one of said probe arms contacts a cylindrical object said biasing means acts to urge both said arms into engagement with' the object on either side of the axis thereof and equidistant therefrom, and said mounting member is moved on said guide means.

17. An element having probe arms symmetrically disposed on either side of a center line, said arms being adapted to engage the peripheral surface of a cylindrical object, a support member for said element, means biasing 'said element away from said support member so that said probe arms may contact the peripheral surface of a cylindrical object and tend to seat themselves equally on either side of the axis thereof, mounting means, said mounting means including guide means, said support member being freely movable on said guide means in a direction substantially perpendicular to the direction of movement of said probe member by said biasing means.

References Cited by the Examiner UNITED STATES PATENTS 1,808,392 6/ 1931 Waldrich 5149 2,312,161 2/1943 Hartman 5149 2,544,156 3/1951 Hathaway 51-98 X 2,864,211 12/1958 Balsiger et a1. 51289 3,056,243 10/1962 Flanders 51-289 3,070,925 1/ 1963 Woodford et al 5149 FOREIGN PATENTS 476,363 12/1937 Great Britain.

LESTER M. SWINGLE, Primary Examiner.