US2442042A

US2442042A - Grinding apparatus

Info

Publication number: US2442042A
Application number: US655486A
Authority: US
Inventors: Alfred E Hamilton
Original assignee: Individual
Current assignee: Individual
Priority date: 1946-03-19
Filing date: 1946-03-19
Publication date: 1948-05-25
Anticipated expiration: 1965-05-25

Description

9 Sheets-Sheet l ATTORNEY May 25, 1948. A. E. HAMILTON GRINDING APPARATUS Filed March 19, 1946 INVENTOR HLFRED .HHIVZ'LT'ON,

E l I J .1 i WHHMMMH HMHH n H IHWMIM H u H .MMM

May 25, 1948. v A. E. HAMILTON GRINDING APPARATUS Filed MaICh 19, 1946 ATTORNEY May 25, 1948. A. E. HAMILTON GRlNDING APPARATUS Filed March 19, 194e 9 Sheets-Sheet 5 ATTORNEY 9 sheetslsheet 4 Filed March 19, 1946 l BY MMM

' ATTORNEY May 25, 1948. A. E. HAMILTON GRlNDING APPARATUS Filed March 19, 1946 9 Sheets-Sheet 5 m wv.

INVENTOR HLFE E. HAMILTON.

ATTORNEY May 25, 1948. A. E. HAMILTON GRINDING APPARATUS Filed March 19, 1946 9 Sheets-Sheet 6 INVENTOR HLF'E EJHNILTN.

ATTORNEY May 25, 1948. A E, HAMILTON 2,442,042

GRlNDING APPARATUS Filed March 19, 19.46 9 Sheets-Sheet '7 Ew D 'SU I@ D @l INVENTOR ALFRED E HQMzL TON ATTORN EY May 25, 1948. A. E. HAMILTON GRlNDING APPARATUS Filed March 19, 1946 9 Sheets-Sheet 8 INVENTOR HL H25 D 5 Hana TON,

ATTORNEY 9 sheets-sheet 9 Filed March 19, 1946 INVENTOR4 HL/-RED E. HHH/1L roN.

BY m v ATTORNEY Patented May 25,'1948 UNITED s'rAr-r-:s f PATE-NT ori-ics dnmnmc arrmrus Alfred E. Hamilton, Pittsburgh, Pa. Anuman March 19. 194e, semi No. escaso 11 Claims.

One object of my invention is to provide apvparatus for snagging or grinding heavy pieces of metal under greater grinding pressures and with a more rapid removal of metal than is possible with various forms of grinding machines heretofore employed.

Another object of my invention is to provide an improved mechanism for moving a grinding wheel and a work piece relative to each other,

during grinding operations. A

Still another object of my invention is to provide an improved means for moving a grinding wheel to operative position on a work piece and maintaining it under desired degrees of grinding pressure. l

A further object of my invention is to provide an improved means and method for preventing loading of the grinding surface of the wheel with particles of metal from the work pieces or with abrasive fines or particles loosened from the wheel itself.

Figure 1 is a fragmentary schematic plan view of the apparatus; Fig. 2 is a side elevational view thereof; Fig. 3 is an elevational view on an enlarged scale of a portion of the table driving apparatus of Fig. 2; Fig. 4 is a sectional view taken on the line IV-IV of Fig. 3; Fig. 5 is an enlarged sectional view taken on the line V-V of Fig. 2 and showing one of the clamping devices for holding a slab on the table; Fig. 6 is lan enlarged cross sectional view of a portion of the apparatus of Fig. 1; Fig. l is an end view of a portion of the apparatus of Fig. 6; Fig. 8 is a view partly in elevation and partly in section looking in the direction of arrows VIII-VIII of Fig. 6; Fig. 9 is a. fragmentary end view of the apparatus, partly in section, showing a portion of the grinding wheel relative to the work; Fig. 10 is a sectional plan view showing mechanism for oscillating the grinding wheel; Fig. 11 is a face view, of a control box for the various motors that operate various parts of the machine; Flg.-12 is an end view thereof, partly in section, and Fig. 13 is a plan view, partly diagrammatic, showing the control mechanisms in the box and their relation to the various motors.

The apparatus comprises a foundation or base I2 having pedestals i3 to which track rails I4 are anchored by means of bolts I5. The table I6 for the slabs or other work pieces is in the form l (QL 51-38) of a carrier that is made up of trucks or buggies i1 that are coupled together by bolts Il and haveanged wheels I3 that travel on the track rails I4 when the table is driven in to-and-fro directions.

A rack or series of longitudinally-aimed racks 2| (Fig. 4) are secured to the under surfaces of the buggies by screws 22. The table is driven along the tracks i4 by a gear wheel 23 (Figs. 3 and 4) that meshes with the rack. The gear wheel 23 is driven from a motor 24 (Fig. l), through a reducer 25, that drives a pinion shaft 23 which carries a pinion 21 that meshes with a gear wheel 23 whose shaft is provided with a pinion 23 (Fig.

l5 3) that meshes with the gear wheel 23 to drive the same. The motor 24 will preferably be of the direct current and reversible type so that the table can be driven in both directions to carry the work pieces' past a grinding wheel that will be hereinafter described.

The floor surface beneath the track rails is sloped toward one end so that the water used in grinding and the detritus and grindings will drain into a sump 3| from which they will be removed.

25 A grinder-supporting carriage 32' (Figs. 6-'7-8) is mounted on a base 33 that extends laterally of the table as shown more clearly in Fig. l, the carriage being supported on anti-friction bearings 34. As shown more clearly in Figs. 6 and 8,

the carriage 32 is reciprocated by a reversible motor 35 that is mounted thereon and has a driving pinion 36 which. through a gear wheel 31, drives a gear wheel 33 that has a threaded hub or nut 39 rigidly secured thereto. The nut 35 39 is mounted between the anti-friction bearings that are positioned between bearing surfaces 4| and 42 that are carried by the carriage 32.

The nut 39 has threaded engagement with a screw 43 that is rigidly held in bearings 44 and 45 that are carried by the base 33. It will be seen that as the motor 35 is driven in its forward and reverse directions, the carriage 32 will be reciprocated transversely of the table, on the bearings at 34, to move a grinding wheel 46 that is mounted on the carriage 32 back and forth across slabs or other work pieces on the table.

A housing 41 of generally cylindrical form is rigidly supported on the carriage 32 and contains bearing rings 43 which support a ring 49 for oscillating movement. The ring rigidly carries at its lower end a member 5|, by means of studs or screws 52. The member 5l is connected to a link 53 which is reciprocated as hereinafter described, to oscillate the ring 49. vA rocking frame 54 is pivotally supported in the frame, and a water spray directed against the grinding wheelby a pipe 50. A motor 51 for driving the grinding wheel is mounted on a base plate 58 that is slidably supported on the rocking frame 54 and is adjusted longitudinally of the rocker -frame by a screw 59,v to control'l the belt tension. The motor 51 has a pair of pulleys 6I that, through belts 62, drive pulleys 63 on the shaft 60 of the grinding wheel 46.

As above stated, the carriage 32 is reciprocated by the motor to move the grinding wheel 15 46 transversely of a slab 65 (Figs. 5 and 9), as the trucks I1 of the table are moved along the track rails I4. The rocking frame 54 is oscillated in a vertical plane (Fig. 6) by a piston contained within a, cylinder 66 to which uid under 20 pressure is admitted through a pipe 61, the piston rod being pivotally connected at 68 to the frame 64. The lower end of the cylinder has`a ball-and-'socket connection at 69 with'the carriage 52, so that the piston and cylinder will 25 accommodate themselves to the arcv through which the rocking frame 54 is moved.

Fluid pressure is directed through the pipe 61 to hold 'the grinding wheel 46 against the work lating and vibratory movement while the carriage 32 is being reciprocated to move the grinding wheel 48 to and fro across the work piece, in order to prevent loading of the grinding surface of the wheel46 by bits of removed metal or crushed nes from the grinding wheel, to thereby maintain the effectiveness of the wheel. The corners of the wheel will first be worn away by this oscillating motion, leaving the abrading surface ofthe wheel in a somewhat convex shape, and it has been found that the oscillating and vibratory movements hereafter referred to assist in removing the grindings from the surface of the wheel and the work piece.

This oscillatory movement is provided by the mechanism shown more clearly in Figs. 2, 8 and 10 and comprises (a gear case 85 that is secured to the carriage 32, and a base 86 for a motor 81. The motor 81 drives the gearing through a belt 88, the belt tension being adjustable by a screw 89. The belt 88 drives a pulley 9| that is mounted on a shaft 92 which carries a gear wheel 93 that, in turn, drives a gear wheel 94 mounted on a shaft 95 (Fig. 10). The shaft 95 has an enlarged end 96 that is supported in a bearing 91 which has lan internally toothed gear ring 96 rigidly mounted therein. The enlarged end 96 serves as a housing for agear wheel 99 anda shaft IIII that is rigidly secured to the gear piece With 8 desired pressure, While the Carriage 30 wheel. The gear wheel 99 meshes with the gear 32 is being reciprocated. vIn order to prevent too great tilting of the frame 54 and consequentl dropping of the grinding wheel, I providea hanger in the form of a chain 1I that will nor-',

3ring 9,8, soa-that when the gear wheel 94 is being irotated, the'g'ear wheel 99 and its shaft |8I will aiso be rotated about their individual axes Ywhich are offset from the axis of the shaft 95.

mally be slack during a; grinding operation but The shaft iol has a crank arm |02 that carwhich will limit the downward movement of the grindingy wheel under theiiuid pressure force when it has passed the edges of the work piece 65. The chain 1| is connected at its lower end to a stud 12 on the rocker frame and at its upper 40 end extends over a sprocket wheel 13 that is keyed to a shaft 14 which also has keyed thereto a worm wheel 15. The worm wheel has mesh engagement with a worm 16 which, when turned by its shaft 16a and hand wheel 16h, will shorten 45 cut off at the pipe 61, the rocking frame may tilt in a. clockwise direction under weight of the motor 51, to lift the wheel from the work, or pressure can be admitted to the upper side of the piston through a pipe 11 which pipe will serve as of the cylinder when pressure is being admitted through the pipe 61 to move the grinding .wheel against a work piece.

As shown more clearly in Fig. 5, the slabs or 'a means for exhausting :fluid from the upper end 65 other work pieces are releasably held on the table by.clamping screws 18 placed at suitable intervals and having threaded engagement with upstanding shoulders 19 on the trucks I1, the trucks also having anges or shoulders 8| at their opposite edges. Clamping blocks or bars 82 have 85 holes to receive reduced ends 63 of the clamping screwsland are recessed in their inner surfaces to receive handle-like extensions 84 that are carried by the inner ends of the screws whereby the screws can be oscillated to move the clamping members 82 into and out of engagement with the edge of the slab and to hold it firmly against the shoulder 8|.

The ring 49, upon which the rocking frame 54 is pivotally supported, is given a combined oscilries a crank pin |93 on which the outer end of the link 53 is journaled, the other end of the link being pivotally connected to the ring 49 (Figs. 6 and 8).

It will be seen that when the shaft 95 is being driven by the motor 81, the movement of the shaft |0I around the axis of the shaft 95 will impart an oscillatory or rocking movement to thering 49 and that there will be a simultaneous vibratory motion imparted to the llink 53 and the ring 49, through rotation of the gear wheel 99 in the ring 95 and consequent rotation of the shaft I0| about its own axis. This gives what might be called a hypocycloidal motion of the ring 49.

For eillcient and accurate operation of apparatus of this kind, it is necessary that there be some synchronlsm of operation, particularly with respect to the table-driving motor 24 and the motor 35 that reciprocates the grinding wheel transversely of the table and the work piece thereon. It is also desirable that there be automatic control of these motors, with respect to the starting and stopping and the reversal thereof. For instance, when the grinding wheel 46 is being reciprocated transversely of the path of travel of the work piece, the reciprocating movements will be in timed relation to the traveling movements of the table I1. For example, at the extreme outward position of the grinding wheel 46 and its carriage 32, a limit switch will be automatically actuated to reverse the motor 35 that drives the carriage, and at this time, a switch will be closed to set the table-driving motor 24 in operation, to move the work table I1 one step. Similarly, at the end of the reverse movement of the grinding wheel and its carriage 32, its motor will be stopped and reversed. and the table-moving motor will again be energized to advance the table another step.

The limit switches that control the reciprocating movements of the carriage 32 and the grinding wheel are adjustable so that the length -of stroke can be varied to suit various widths of work pieces. The limit switches which. control the table-driving motor 24 are also adjustable so that the motor can be started, stopped, and reversed at proper times, at all lengths of I reciprocatory strokes of the grinding wheel. To

zontal slot |08 to receive an arm |01 that is carried by the carriage or casing 32 so that this arm |01 will operate certain of the switches during reciprocating movements of the carriage 32. Shafts |09 and ||0 are journaled in the end walls of the box |04, the shaft |09 having a reduced extension I that extends into the shaft ||0 to give stability to these shafts and to Ipermit rotation of either shaft relative to the other by hand wheels ||2 and |I3 respectively. The

y shafts are held in assembled relation by a nut ||4 that is threaded on to the reduced extension and the shafts are longitudinally shift- ,able as a unit in the box for a purpose hereinafter explained.

A trip arm ||5 has threaded connection with the shaft |09 so that it, together with the shafts |09-||0, will be shifted by the pusher arm |01 at desired intervals. Similarly', a trip arm ||6 has threaded connection with the shaft H0, for adjustment longitudinally thereof. A camming collar ||1, of split form, is tightly secured to the shaft |09 by a tightening screw ||8 and a similar cam collar ||9 is clamped to the shaft ||0 by a screw that extends through the split parts of the collar. The front faces of the members 5|| 6 lie against the front wall of the `box |04 and are thereby held against rotation during turning of the screw shafts |09| |0.

The trip arms ||5 and ||6 carry pointers |2| and |22 respectively, that project through a slot in the front wall of the box and register with scales on the front wall of the box which show the spacing of the trip arms and hence the points at which the carriage 32 will, through the arm |01, operate the control switches during reciprocating movements of the grinding wheel.

The camming collar ||1 trips a limit switch |23 that controls the motor 35,. at a predetermined point in the travel of the carriage 32 and its arm |01 in one direction. The point of travel at which this actuation/0f the switch is effected is determined by the point at which the trip arm ||5 is adjusted on its shaft |09 and hence the point at which the arm |01 actuates the shaft in that direction. Similarly, the shafts |09| I0 will be pushed in the opposite direction by the arm |01 on the return stroke of the carriage 32 and the grinding wheel. The arm |01 will shift the trip arm ||6 and the shafts, to effect operation of a switch |24 that also controls the motor 35 which reciprocates the carriage 32 and the grinding wheel. It will be seen that these switches both control circuits-through a reversing starter |25 and a rheostat |26 to the motor 35 to stop the same and to again start it in the opposite direction at each end of a reciprocating stroke. The adjustment of the arms ||5 and transversely movable carriage.

H6 is for adapting the length of reciprocating stroke to the width of the work pieces.

Hand wheels |21 and |28 are provided for adjusting limit switches |29 and |30 respectively with respect to the camming collars ||1||9 so that the table-driving motor 24 will be stopped, started and reversed in predetermined relation to the reciprocatory movements of the carriage 32. To this end, the switches |29 and |30 control a circuit through a reverser and motor starter |3| and a rheostat |32.

When the arm |01 strikes the trip arm ||6 on backward movement of the grinding wheel and its carriage 32, the switch |24 will be actuated by the camming collar I6 to close the circuit and the switch arm |23 released to allow that portion of the circuit to be broken, thereby effecting a reversal of current in the reversing starter |25. At this time, the collar ||9 has actuated the switch lever at |30 thereby completing the circuit through the reversing starter |3| and causing the motor 24 to start and run only momentarily, the speed of the Vmotor being regulated by the rheostat |32. The rheostat is adjusted to -control the length of travel of the table upon tripping of the limit switch |30, this speed being more or less variable according to the speed of the reciprocating carriage 32.

During these operations, the switch |29 ordinarily will have been adjusted back by turning of the knob |21 so that it will not be actuated during regular forward grinding movements. This limit switch |29 is held in reserve for controlling the intermittent movements of the table in its backward direction, in which case the switch |30 will be adjusted to an inoperative position by its knob |28. Since the limit switches |23 and |24 are fixedly fastened to the box and limit switches |29 and |30 are adjustable, the relation between |23 and |29 can be varied and the relative positions of the switches I 24 and |30 also changed. Therefore, the intermittent movement of the table driven by the motor 24 is adjustable with respect to the reciprocating motion of the In other words, the switch |30 can be adjusted to trip just before the wheel `has finished its grinding movement across the slab, or after the wheel has fully completed `such movement, and the limit switch |29 will be operative in a like manner during backward movement of the table.

As shown in Fig. 11, push-button controls are provided at the front of the control box. At |34, there is push-button control of the motor 35.

At |36 is the push-button control for starting and stopping the motor 81 that operates the vibrating or hypocycloidal device for oscillating the grinding wheel. At |31, there is push-button control for starting and stopping the motor 51 that rotates the grinding wheel. At |38 is the push-'button station for starting and stopping the table-driving motor 24, through the reversing starter |3| and the rheostat |32. An across-theline switch is provided at |39 for starting a motor |40 that drives a pump (not shown) which will furnish a grinding solution to the grinding wheel.

In order to control the operation of the piston in the cylinder 66, and hence the pressure of the grinding wheel on the work, I provide a handle lever |4| and a four-way valve |42 for controlling the admission of air to the upper and lower ends of the cylinder 66. yIt will be understood that the pipes 61 and 11 are of flexible hose-like form and of suiiicient length to permit the travel of the carriage and the cylinder 66 relative to the control box I 04. At one position oi! the valve |42, air will -be admitted to the upper end oi' the piston and exhausted from the lower end thereof, while at the opposite position, the duid pressure will be admitted to the lower end of the piston to swing the rocking frame 54 in a direction to move the grinding wheelagainst the work. A pressure regulator |43 is provided in the air line |44 to control the pressure to the underside of the piston in the cylinder 66 and hence the grinding pressure. A cam disc |45 is rigidly secured to the extended rotary barrel |48 of the valve |42 in position to engage a pressure regulating pin |41 that operates within the regulating valve |43 to vary the grinding pressure. This disc is rotatably adjustable in order to limit the grinding pressure to a desired predetermined maximum degree.

I claim as my invention:

l. Grinding apparatus comprising a table for a work piece, a grinding wheel mounted on an axis that is approximately parallelto the path of travel of the table, means for reciprocating the grinding wheel crosswiseof the table, means for advancing the table past the grinding wheel, in step-by-step movements, a device actuated by the reciprocating means, for controlling the movements of the table, and means for oscillating the axis of the grinding wheel in a plane perpendicular to the plane of the table, during said crosswise movements.

ZifGrinding apparatus comprising a table for a wafgpiece, a grinding wheel mounted on an axis tliatlisl approximately parallel to the path of travel ai the table, automatically operable means for reciprocating the grinding wheel crosswise of the table, means for advancing the table past the grinding Wheel, in step-by-step movements, a device actuated by the reciprocating means, for controlling the movements of the table, means for oscillating the axis of the grinding wheel in a plane perpendicular to the plane of the table during said crosswise movements, and means for manually controlling the said'crosswise movements of the grinding wheel independently of the automatically operable means.

3. Grinding apparatus comprising a table for a work piece, an electric motor for moving the table, a grinding wheel mounted on an axis that is approximately parallel to the path of travel of the table, an electric motor for reciprocatingthe gr'nding wheel crosswise of the table, and a control device operated in timed relation to said reciprocatory movements, for periodically energizing and deenergizing the table-driving motor.

4. Grinding apparatus comprising a table for a work piece, an electric motor for moving the table, a grinding wheel mounted on an axis that is approximately parallel to the path of travel of the table, an electric motor for reciprocating the grinding wheel crosswise of the table, and a control device operated in timed relation to said reciprocatory movements, for periodically energizing and deenergizing the table-driving motor,

`the said device being operative at the end of each reciprocatory movement of the grinding wheel.

5. Grinding apparatus comprising a table for a work piece, an electric motor for moving the table, a grinding wheel mounted on an axis that is approximately parallel to the path of travel of the table, an electric motor for reciprocatingA the grinding wheel crosswise oi' the table, means for automatically reversing the second-named motor at the end of each reciprocatory stroke, and a control device operated in timed relation to said reciprocatory movements, for periodically energizing and deenergizing the table-driving motor, the said device being operative at the end gheazh reciprocatory movement of the grinding 6. Grinding apparatus comprising a table ior motor, the. said device being operative at the end of each reciprocatory movement of the grinding wheel, and means for manually controlling the length of reciprocatory stroke of the grinding wheel independently oi the said automatic means.

'7. Grinding apparatus comprising a carrier for a work piece, a grinding wheel mounted on an axis that is approximately parallel to the plane of the carrier, means for imparting relative Itraveling movements to the carrier and the grinding wheel, in directions transversely of and approximately parallel to the axis of the grinding wheel, means for rotating the wheel, and means for oscillating the grinding wheel in a plane that is perpendicularto the plane of the carrier and on an axis that iaparalleltetheend l faces of the grinding Wheeland which lsspacad' a substantial distance from-the grinding plane.

8. Grinding apparatus comprising a carriage that is movable in a given path, a bearing on the carriage, a bearing ring in said bearing, rotatable about an axis that is parallel to said path, a rocking frame extending through said ring and pivoted thereon, intermediate its ends, on an axis transverse to the ilrst-named axis, a grinding wheel rotatably mounted on the outer end of said frame, a motor mounted on the inner end of said frame and having driving connection with the grinding wheel, a cylinder and a piston respectively connected to the inner end of the frame and the carriage, the said connections being pivotal, means for supplying iiuid pressure to said cylinder to rock the frame on its axis, and means foroscillating the frame about the axis of the bearing ring.

9. Grinding apparatus comprising a carriage that is movable in a given path, a bearing on the carriage, a bearing ring in 'said bearing, rotatable about an axis thatis parallel to said path, a rocking iframe extending through said ring and piv- 1 oted thereon, intermediate its ends, on an axis ing ring, Va second motor on the carriage, and` means operative by said second motor for imparting reciprocating movements to the carriage, in said path.

l0. 'I'he method of grinding, which comprises moving a work piece past a grinding wheel while rotating the wheel on an axis that is approximately parallel to the path oi travel oi the work piece, while oscillating the grinding wheel on an axis that is Itransverse to its axis of rotation and parallel to the face of the work piece and While bodily moving the grinding wheel on the work piece in directions transversely of said path, the said axes of oscillation being spaced a substantial distance above the plane of contact by the grinding wheel with the work piece when the wheel is positioned above the work piece.

11. The method of grinding, which comprises moving a work piece past a grinding wheel while rotating the wheel on an axis that is approxi? mately parallel to the path of travel of the work piece, while oscillating the grinding wheel on an axis that is transverse to its axis, of rotation and parallel to the face of the work piece and while bodily moving the grinding wheel on the work piece in directions transversely of said path, and moving the work piece step-by-step in periodic relation to the transverse movements of the grinding wheel.

ALFRED E. HAMILTON.

10 REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 411,839 Taft Oct. 1, 1889 725,142 Robinson Apr. 14, 1903 1,866,212 Hunford et al July 5, 1932 1,952,334 Robinson Mar. 27, 1934 2,308,843 Wilson Jan. 19, 1943 2,403,341 Carlson July 2, 1946 FOREIGN PATENTS Number Country Date 340,910 Great Britain Jan. 8, 1931