US3047988A

US3047988A - Feed mechanisms for grinding machines

Info

Publication number: US3047988A
Application number: US791684A
Authority: US
Inventors: Ralph E Price
Original assignee: Landis Tool Co
Current assignee: Landis Tool Co
Priority date: 1959-02-06
Filing date: 1959-02-06
Publication date: 1962-08-07
Anticipated expiration: 1979-08-07
Also published as: FR1311657A

Description

Aug. 7, 1962 R. E. PRICE 3,047,988

FEED MECHANISMS FOR GRINDING MACHINES Filed Feb. 6, 1959 v 4 Sheets*Sheet l 37 O 'l I RALPH E. PRICE INVENTOR.

ATTORNEYS Aug. 7, 1962 R. E. PRICE FEED MECHANISMS FOR GRINDING MACHINES 4 SheetsSheet 2 Filed Feb. 6, 1959 I on E 0 in m m P E G W w w E I I I. ll W L A L I! R. ulh Hh I II I m 01 A Q1 W l I 3 mm Z 5 IT 3 FIIIIIL m. 2 I u I -L. Ill]. c j 0.. Q ii i IFIK. w mN & G 0 mm II n Ill v V N OE l m mm mm N E ATTORNEYS Aug. 7, 1962 R. E. PRICE FEED MECHANISMS FOR GRINDING MACHINES 4 Sheets-Sheet 5 Filed Feb. 6, 1959 Aug. 7, 1962 R. E. PRICE FEED MECHANISMS FOR GRINDING MACHINES 4 Sheets-Sheet 4 Filed Feb. 6, 1959 lg E E W wmq l m M I m E O H P L A R 8 6 6 6 I [I 7 ll 4 mplplllllllul. m J un -w .E L W 00 bill/ .194 daiiblo w W El INVENTOR T atent Giiice 3,047,988 Patented Aug. 7, 1962 3,047,988 FEED MECHANISMS FOR GRINDING MACHINES Ralph E. Price, Waynesboro, Pa., assignor to Landis Tool Company, Waynesboro, Pa. Filed Feb. 6, 1959, Ser. No. 791,684 9 Claims. (Cl. 51-165) The following specification relates to a novel improvement in a resetting mechanism for grinding machines.

In the operation of a rotary grinding wheel upon a workpiece, the gradual wearing away of the grinding wheel necessitates frequent readjustment so that a uniform range of movement can be maintained with respect to the successive workpieces. Inother words, it is of great importance to assure the grinding operations starting from a predetermined fixed distance from the workpiece. In this way, the successive advancing movements of the grinding wheel will always begin at the same distance from the work axis.

To attain this object, it is important that the resetting of the grinding wheel shall be controlled to this end and that the cutting surface of the grinding wheel is always reset to the same position with relation to the axis of the workpiece. 7

One object of this invention is to provide a pawl and ratchet feed mechanism which will advance and retract the wheel slide with due compensation for wheel wear or other variations.

A still further object of the invention is to locate the pawl and ratchet feed mechanism in direct relation to the feed screw and independent of the conventional hand wheel adjustments.

Among the objects of my invention is to provide a drive for the feed screw which will minimize backlash during operation.

As illustrating this invention, the preferred form is shown on the accompanying drawings in which:

FIG. 1 is a plan view, partly in horizontal section of the improved ratchet feed for grinding machines;

FIG. 2 is an end elevation of the ratchet operated drive for the initial shaft;

FIG. 3 is a side elevation partly in vertical section of the same;

FIG. 4 is a side elevation partly in-vertical section of the intermediate shaft;

FIG. 5 is a vertical longitudinal section of the feed screw and associated gearing;

FIG. 6 is a perspective view of a modified train of gearing for traversing the wheel slide relative to the feed screw;

FIG. 7 is a fragmentary side elevation of the shaft and inclined keyway; and

FIG, 8 is a vertical longitudinal section on line 88 of FIG. 1.

It will be understood that the invention deals with the effective operation of a grinding wheel 7 having one or more units which are operated against a workpiece 8 held and rotated in the usual manner in a conventional grinding machine.

For-the purpose of reciprocating the grinding wheel slide 45 with a suitable compensating adjustment of the slide, provision is made for a train of gearing which begins with shaft 11 as shown in FIGS. 1, 2 and 3. This shaft has a reversible ratchet wheel '12 keyed to the shaft 11. The ratchet wheel 12 includes a hub portion 13. The latter is journalled within a bear-ing 14 supported in the frame 15.

A toothed segment 16 is journalled on the bearing 14 for controlling the rate of forward feeding of the grinding wheel slide 45.

A similar toothed segment 17 is journalled on the bearing 14 opposite from the segment 16.

A pin 18 is mounted on the segment 16 and carries a spring-held pawl 19. This pawl is in engagement with the ratchet wheel 12.

A link 20 connects the rear of the segment 16 to the piston rod 21 of a hydraulic or pneumatic cylinder 22. This serves to advance the toothed segment 16 and the pawl 19 during the feeding operation.

A pin 23 is mounted on the segment 17. The pin 23 carries a spring-held pawl 24 on the segment 17.

A link 25 on the rear of the segment 17 connects the latter to a piston rod 26. The piston rod is advanced by a fluid resetting cylinder 27.

A toothed stop member 28 is mounted on pivot 2 which forms part of frame 15. The stop member 28 is operated by the fluid motor 39 so that the member 28 is brought into engagement with the segment 16 and thus when the fluid motor 30 is actuated serves to dimit the forward feeding movement of the pawl 19.

A similar toothed stop member 31 also pivoted at 29 on the frame 15, is capable of being set in adjusted position by a screw-threaded adjusting rod 32.

The shaft 11 carries a spiral worm gear 33, at its opposite end.

Beneath the opposite end of the shaft 11 and journalled in the frame 15, is a transverse shaft 34. This shaft carries a worm wheel 35 in engagement with the worm gear 33.

The opposite end of the transverse shaft 34 carries a worm gear 36.

A worm wheel 37 is journalled in

bearings

38, 38 in the frame 15 above and at right angles to the transverse shaft 34. The worm wheel 37 is in engagement with the worm gear 36 on the end of the shaft 34.

The worm wheel 37 is keyed to feed screw 40. There is an inclined key slot 4-1 on the feed screw 40 opposite the worm wheel 37, while a corresponding inclined keyway 42 is on the inner surface of the worm wheel 37. The key-way extends the full length of the worm wheel 37. A key 43 fits in the recesses provided :by the slot 41 in feed screw 40 and key-way 42 in worm wheel 37, and is subject to a limited longitudinal movement relative to these parts.

At the opposite end of the feed screw 40, there is a vertical shaft 44. This vertical shaft is journalled in the grinding wheel slide 45. $lide 45 is mounted on bed 10 for movement toward and from a workpiece. A pinion or worrn wheel 46 at the bottom of shaft 44 engages the thread 47 on feed screw 40.

The upper end of the vertical shaft 44' is equipped with a worm wheel 48. This worm wheel is in engagement with a horizontal worm gear 49 on shaft which extends forwardly to a convenient position to receive a hand wheel 50. The pinion 46 is thus a feed screw engaging means both when the drive is from the latter and from the hand wheel.

In the housing for the hand wheel 59, there is provided a hydraulic motor 51. This has a suitable piston 71 and rack 72 in engagement with a pinion 73 on the shaft 70 to provide rapid advance of the wheel slide 45 for feed in fast grinding. This mechanism is similar to the means for turning the hand wheel shaft 63 in FIG. 6.

The preliminary feed through the hand wheel shaft 70 by the hydraulic motor 51 acts through worm-wheel 48 and pinion 46 to advance the wheel slide 45 relative to the feed screw 40.

After the fast grinding has been accomplished, the further advance of the wheel slide 45 is accomplished by means of the pressure cylinder 22 and segment 16 operating through pawl 19 on the ratchet 12. The extent of each stroke of pawl 19 is controlled by means of the toothed member 28.

spa /pea The extent of this advance is, of course, dependent upon the ultimate size of the finished work, and the advance of the wheel slide 45 compensates for wear on the wheel 7.

After the work has been reduced to size, pressure cylinder 27 operates to reset the ratchet l2 and the shaft ll, retracting the wheel slide 45. This retraction is for a definite prearranged distance established by the adjustment of a stop member 31 by the screw-threaded member 32 and a predetermined number of strokes of pawl 24. It follows that the feed screw 4t) and the wheel slide 4'5 are thus left in position so that the next feed movement provides the same approach to the work as occurred in the initial feeding movement.

It will be observed that the rotation of the worm wheel 37 on the feed screw 40 is dependent upon the obliquely arranged key 43. The operation of the latter is to take up backlash between the worm wheel 37 and worm gear 36 when the feed screw 40 is moved bodily endwise during the rapid feed movement.

A modified arrangement of the wheel slide feed and resetting is shown in FIG. 6 diagrammatically.

In this arrangement, the feed screw '2. is slidably arranged in the base of the grinding machine. The screw 52 is adapted for hydraulic rapid approach movement toward the work, as indicated on the diagram.

A worm wheel 53 keyed to feed screw 52 is slidably carried on the rear portion of said feed screw. This worm wheel 53 engages a worm gear 54 on a transverse shaft 54.

The outer end of the shaft 54 carries two

ratchet wheels

55 and 57. Wheel 55 is arranged for advancing the feed screw 52 and adjusting it for necessary dressing. It is operated by means of pawl 56 which is actuated in the manner indicated for the pawl 19 on FIG. 2.

A resetting ratchet wheel 57 also on shaft 54, serves for retracting the feed screw 52. This is accomplished by means of pawl 58 serving to reset the feed screw 52 and shaft 54 a fixed amount as done by the pawl 24-.

The horizontal shaft for longitudinally adjusting and feeding the wheel slide 45 is shown at 59. At its left end, it has a pinion 66 which is in engagement with the thread 61 on the feed screw 52.

At the right hand end of the shaft 59 is a worm wheel 62. The worm wheel 62 is in engagement with the worm gear 64 on a manual adjustment shaft 63. The shaft 63 has a pinion 65.

Opposite the pinion 65, there is mounted a pressure cylinder 66 having a reversible piston 67. The piston 67 is provided with rack 68 having rack teeth 69. This rack engages the pinion 65. Pressure applied within the cylinder 66 is effective to produce rotation of shaft 63 through a range corresponding to the length of cylinder 66. This serves to rotate shaft 59 along the thread 61 which at that time is stationary. Consequently, the wheel slide 45 in which shaft 59 is horizontally mounted, can be advanced to the desired point at a rate suitable for grinding.

This movement can also be accomplished by fluid pressure in the

cylinders

74, 75 built in the base around the feed screw 52.

The piston in cylinder 22 and the one actuating pawl 56 may be operated by air pressure. The velocity of the piston under air pressure is greater than with hydraulic fluid power. Also the piston strikes against the front end of the cylinder 22. It follows that a slight jar is imparted to the ratchet wheel 12 and through the entire gear train to the grinding wheel slide 45. This overcomes the inertia of the parts and assures each individual advance movement being transmitted to the wheel slide 45. The latter is therefore advanced by an infinitesimal amount even as small as of the order of ten to twenty micro-inches.

The final feeding movement is accomplished through the ratchet wheel 55 and shaft 54 and the worm wheel 53 on feed screw 52. This movement is stopped by suitable size control mechanism such as a caliper when the desired work size is reached. The size control mechanism also initiates a predetermined number of impulses of pawl 53 to turn the shaft 54 in the opposite direction and thus give a predetermined longitudinal retraction of the feed screw 52. As a consequence, the wheel slide adjusting shaft 59 is retracted a predetermined amount for every forward movement. The amount of retraction is generally less than the ratchet operated advance by the amount of the wheel wear. The actual difference between the feed and reset movements varies with changes in the machine such as temperature, stresses, etc.

In either modification, the wheel slide 45 is caused to advance by an indefinite amount determined by the necessity of reducing the workpiece 8 to the ultimate size. This involves the operation of the pawl and ratchet mechanism 55 to Wheel wear and other variables are automatically compensated for by the resetting of the ratchet mechanism as described above. It therefore follows that each successive advance of the wheel slide 45 starts from a point definitely established with respect to the extent of travel desired toward the workpiece 8. Other equivalent one-way step by-step incremental movements may be used in place of the pawl and ratchet movement described.

The operation of this invention is similar in sequence to that shown in application Serial No. 650,902, filed April 5, 1957.

While the invention has been described in the above examples, it may be embodied variously without departing from the scope of the following claims.

What is claimed is:

1. In a grinding machine, a bed, a work support on said bed, a grinding wheel support mounted slidably on said bed for movement toward and from said work support, a grinding Wheel rotatably mounted on said grinding Wheel support, means for feeding said grinding wheel support including a feed screw and screw-engaging means on said wheel support, drive means for effecting movement of said grinding wheel support relative to said feed screw comprising a hand wheel mechanism on said grinding wheel support at a point remote from said feed screw, continuously moving means for rotating said hand wheel mechanism to move the said grinding wheel support relative to said feed screw for a preliminary grinding operation, connections between said hand wheel mechanism and said feed screw, independent means for rotating said feed screw including a pawl and reversible ratchet mechanism mounted on the bed of the grinding machine adjacent said feed screw, and operating connections between said pawl and ratchet mechanism and said feed screw which are remote from said connections between said hand wheel mechanism and said feed screw.

2. In a grinding machine, a bed, a work support on the bed, a grinding wheel support mounted slidably on said bed for movement toward and from said work support, a grinding wheel rotatably mounted on said grinding wheel support, means for feeding said grinding wheel support including a feed screw and screw-engaging means on said wheel support drive, means for effecting movement of said grinding wheel support relative to said feed screw including a hand wheel mechanism on said grinding wheel support at a point remote from said feed screw, continuously moving means for rotating said hand wheel mechanism to move the said grinding wheel support relative to said feed screw for a preliminary grinding operation, connections between said hand wheel mechanism and said feed screw, means for rotating said feed screw including a pawl and reversible ratchet mechanism mounted on the bed of the grinding machine adjacent said feed screw, and operating connections between said pawl and ratchet mechanism and said feed screw which are remote from said connections between said hand wheel mechanism and said feed screw including a gear driven by said ratchet and a gear on said feed screw co-acting with said ratchet-driven gear.

3. In a grinding machine, a bed, a work support on said bed and having means for rotatably supporting a worn piece, a grinding wheel support slidably mounted on said support, a grinding wheel rotatably mounted on said grinding wheel support, a feed mechanism for moving said grinding wheel support comprising a feed screw and screw-engaging means on said wheel support, drive means for rotating said feed screw comprising a gear keyed to said feed screw, means for rotating said gear, a key in said feed screw, a key way in said gear, said key and said key way being inclined to the axis of said feed screw, means for effecting bodily endwise movement of said feed screw to advance said grinding wheel to operative position, said inclined key and key way being responsive to said endwise movement to efiect a relative rotation between said feed screw and said gear whereby to take up backlash between said gear and said gear driving means.

4. in a grinding machine having a bed, means on said bed for supporting a workpiece, a grinding wheel support, a grinding wheel rotatably mounted on said grinding wheel support, a feed mechanism for moving said grinding wheel support toward and from said work support comprising a feed screw, a screw-engaging member on said grinding wheel support in operative relation with said feed screw, continuous moving means operable between predetermined limits =for actuating said screw-engaging member to move said grinding wheel support relative to said feed screw for a preliminary grinding operation, a reversible ratchet mechanism on said bed operable after said pre-- liminary operation has ended for rotating said feed screw by increments until it is stopped at the end of a grinding cycle, and means for reversing said ratchet mechanism after each grinding cycle by substantially a fixed amount.

5. In a grinding machine having a bed, means on said bed for supporting a workpiece, a grinding wheel support, a grinding wheel rotatably mounted on said grinding wheel support, a feed mechanism for moving said grinding wheel support toward and from said work support comprising a feed screw, a screw-engaging member on said grinding wheel support in operative relation with said feed screw, continuous moving means operable between predetermined limits for actuating said screw-engaging to move said grinding wheel support relative to said feed screw for a preliminary grinding operation, a gear on said feed screw, a reversible ratchet mechanism connected to said gear and operable after said preliminary operation has ended for rotating said feed screw by increments relative to said screw-engaging member until it is stopped and means for reversing said ratchet mechanism after each grinding cycle by a substantially fixed amount from the point to which said ratchet mechanism has advanced.

6. In a grinding machine, a bed, a work support on said bed, a grinding wheel support mounted on said bed for movement toward and from said work support, a grinding wheel rotatably mounted on said grinding wheel support, means for feeding said grinding wheel support including a feed screw in said bed and screw engaging means in said grinding wheel support, continuous moving means operable between predetermined limits for actuating said screw engaging means to move said grinding wheel support relative to said feed screw for a fast grinding operation, means for rotating said feed screw including an increment feed actuating mechanism mounted on said bed and including power operated means for actuating said increment means a varying amount in one direction for operating said feed screw to feed said grinding wheel during a finish grinding operation, and a second power means for actuating said increment means by a fixed amount in the opposite direction for resetting said increment feed actuating mechanism and said feed. screw.

7. in a grinding machine having a bed, means on said bed for supporting a workpiece, a grinding Wheel support, a grinding wheel'rotatably mounted on said grinding wheel support, a feed mechanism for moving said grinding wheel support toward and from said work support comprising a feed screw, a screw engaging member on said grinding wheel support in operative relation with said feed screw, continuous moving means on said grinding wheel support operable between predetermined limits for actuating said screw engaging member to move said grinding wheel support relative to said feed screw for a preliminary grinding operation, means for rotating said feed screw in engagement with said screw engaging member to move said grinding wheel support relative to said feed screw for a finish grinding operation comprising an incremental actuatini means on said bed adjacent said feed screw, and means connecting said incremental actuating means and said feed screw.

8. in a grinding machine, a bed, a work supporting means on said bed, a grinding wheel support on said bed, a grinding wheel rotatably mounted on said grinding wheel support, a feed mechanism for moving said grinding wheel support toward and from said work support coma feed screw rotatably mounted in said bed, a screw engaging member rotatably mounted in said grinding wheel support in operative relation with said feed screw, continuous moving means operable between predetermined limits for rotating said screw engaging member to move said grinding wheel support relative to said feed screw and said bed for a preliminary grinding operation, means for rotating said feed screw relative to said screw engaging member to advance said grinding wheel support relative to said feed screw for a finish grinding operation comprising an incremental actuating means mounted on said bed adiacent said feed. screw and connections between said actuating means and said feed screw.

9. In a grinding machine, a bed, work supporting means on said bed, a grinding wheel support on said bed, a grinding wheel rotatably mounted on said grinding wheel support, a feed mechanism for moving said grinding wheel support toward and from said work support comprising a feed screw rotatably mounted in said bed, -a screw engaging member rotatably mounted in said grinding wheel support in operative relation with said feed screw, means for moving said feed screw endwise to advance said grinding wheel support to grinding position, continuous moving means operable between predetermined limits for rotating said screw engaging member to move said grinding wheel support relative to said feed screw and said bed for a preliminary grinding operation, means for rotating said feed screw relative to said screw engaging member to advance said grinding wheel support relative to said feed screw for a finish grinding operation comprising an incremental actuating means mounted on said bed adjacent said feed screw, and connections between said actuating means and said feed screw.

References @ited in the file of this patent UNITED STATES PATENTS 2,378,903 Baldenhofer June 26, 1945 2,486,244 Balsiger et a1 Oct. 25, 1949 2,692,457 Bindszus Oct. 26, 1954 2,862,338 Hill Dec. 2, 1958 2,897,639 Hill Aug. 4, 1959 2,931,145 Hill Apr. 5, 1960 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION P atent No. 3,047,988 August 7 1962 Ralph E. Price It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 4, line 57, after "support," insert a comma; column 5, line 40, after "screwengaging" insert member Signed and sealed this 25th day of December 1962.,

,SEAL) Attest:

DAVID L. LADD ERNEST W. SWIDER Commissioner of Patents Attesting Officer