US3881886A

US3881886A - Grinding machines and loading mechanism therefor

Info

Publication number: US3881886A
Application number: US411030A
Authority: US
Inventors: Stanley William Hoare
Original assignee: Newall Engineering Co Ltd
Current assignee: Newall Engineering Co Ltd
Priority date: 1973-10-30
Filing date: 1973-10-30
Publication date: 1975-05-06
Anticipated expiration: 1992-05-06

Abstract

A loading mechanism for use on a grinding machine comprises a magazine for delivering a series of components to a loading station; a slidable component carrier; means for moving the carrier from the loading station to a grinding station; means on the carrier for receiving a component from the magazine at the loading station and for supporting the component during said movement of the carrier; a rotary head disposed at the grinding station; and a controllable magnet position for attracting a component from the carrier into engagement with the rotary head for rotation therewith.

Description

United States Patent 1 [In 3,881,886

Home 1 May 6, 1975 l l GRINDING MACHINES AND LOADING 3513,596 5/1970 Beauchet 51/5 D MECHANISM THEREFOR [75] Inventor: Stanley William Hoare, Peterhorough, England [73] Assignee: The Newall Engineering Company Limited, Peterborough, England {22] Filed: Oct. 30, 1973 [21] Appl. No.1 411,030

[52] U.S.Cl. 51/5 D;5lll03 WH;51/215 H [51] Int. Cl. B241; 5/22; B24b 5/34; B24b 49/20 158] Field of Search... 51/103 WH. 215 (Pt 215 H, 51/5 D [56] References Cited UNITED STATES PATENTS 2.912.798 11/1958 Seide] 51/103 WH 3,284,959 5/1964 Seidel vvvv .7 51/103 WH Primary ExaminerDonald G. Kelly Assistant Examiner-Margaret M. Joyce Attorney, Agent. or FirmEdward F. Connors [57 I ABSTRACT A loading mechanism for use on a grinding machine comprises a magazine for delivering a series of components to a loading station; a slidable component carrier; means for moving the carrier from the loading station to a grinding station; means on the carrier for receiving a component from the magazine at the loading station and for supporting the component during said movement of the carrier; a rotary head disposed at the grinding station; and a controllable magnet position for attracting a component from the carrier into engagement with the rotary head for rotation there with.

11 Claims, 7 Drawing Figures {I} moan mum v 1125 PATENIEDHAY GREYS 3,881,886

SHEEI 1 if 5 SHEET 2 0F 5 PATENTED MAY 6197s PATENTEUHAY SIHYS SHEET 4 BF 8 LESS; 223

GRINDING MACHINES AND LOADING MECHANISM THEREFOR This invention relates to machines for grinding relatively small inner rings of hearings or similar components. and particularly to a loading mechanism for such a machine.

The grinding operation performed on small inner bearing rings comprises loading the machine with an unground component, grinding the component and unloading the ground component ready for reloading the machine. A substantial part of the period of each grinding operation is taken up by loading and unloading actions. the time taken for grinding small inner bearing rings of up to about one or two inches diameter. for ex ample. being relatively short. compared to the total period. Thus to cut down the period of a grinding operation. a machine must be capable of more rapid loading and unloading. The present invention relates to a loading mechanism for such a machine.

According to the invention, there is provided a loading mechanism for a grinding machine comprising a magazine which is arranged to deliver a series of components to a loading station. a slidable component carrier which is adapted to receive a component from the magazine at the loading station and to carry the component from the loading station to a grinding station. a rotary head which is disposed at the grinding station, and a controllable magnet positioned for atrracting a component from the carrier into engagement with the rotary head for rotation therewith.

Preferably the carrier is provided with means for supporting a component peripherally during movement from the loading station to the grinding station. where the supporting means may comprise at least one supporting shoe.

The carrier is preferably arranged to withdraw a component from the grinding station. means being provided on the carrier for disengaging the component from the rotary head.

The controllable magnet is preferably arranged to he activated when the carrier reaches the grinding station and deactivated after a set time interval. the means on the carrier for disengaging a component comprising a projection which is arranged to engage the periphery of the component as the carrier moves away from the grinding station after the controllable magnet is deactivated.

An unload chute may be provided for the removal of a component after it has been disengaged from the rotary head.

The controllable magnet preferably comprises an electromagnetic face-plate carried by the rotary head.

In a preferred embodiment. the magazine is arranged to deliver two components at a time to the loading station; and the carrier is adapted to carry two components at a time to the grinding station. there being provided at the grinding station two rotary heads. a controllable magnet for each head which is positioned for attracting one component from the carrier into engagement with the resepctivc rotary head.

According to a further aspect of the invention. there is proxidcd a grinding machinc including a grinding wheel. a dresser mechanism and loading mechanism as hcrcinbeliirc described. in I'llc'll when the dresser mechanism is advanced towards the grinding wheel to compensate for grinding hccl car by a predetermined distance. the loading mechanism is advanced towards the grinding wheel simultaneously by the same predetermined distance.

Preferably. means are provided for feeding the carrier towards the grinding wheel at a variable, controllable rate during the latter part of its movement from the loading station to the grinding station.

Reference will hereinafter be made to the accompanying drawings. of which:

Flg. l is a diagrammatic elevational view of a grind-' ing machine incorporating one embodiment of a loading mechanism according to the present invention;

FIG. 2 shows a plan view of the loading mechanism of FIG. 1, in greater detail and with a part broken away;

FIGS. 3 and 4 show an elevational view of the loading mechanism shown in FIG. 2 with the component carrier in two different operating positions;

FIG. 5 is a cross sectional view taken along line 5-5 on FIG. 4;

FIG. 6 is a diagrammatic elcvational view of part of a grinding machine incorporating a second embodiment of the invention; and

FIG. 7 is a diagrammatic plan view of the machine shown in FIG. 6, taken along the line 7-7.

Referring to FIG. I, a grinding machine I is provided with a grinding wheel 2. which is rotated by means of a wheel spindle drive motor 3. A dresser mechanism 4 is provided with a dresser feed slide 5 and a dresser traverse slide 6 so that a dresser tool unit 7 can be advanced towards the wheel 2. and traversed across the width of the wheel 2 at the same time. The rate at which the dresser tool unit 7 is advanced towards the wheel 2 is determined by a conventional ratchet and pawl type of device shown diagrammatically at 8. The rate is determined as a series of incremental steps of about I or 2 thousandths of an inch at predetermined intervals as hereinafter described. A coolant outfall 9 is also provided on the machine for the coolant used in grinding.

A component loading mechanism It) is located at the other end of the machine from the dresser mechanism 4, and includes a pair of inclined loading chutes ll. constituting a magazine having two outlets. down which unground components are permitted to roll until a loading station is reached as hereinafter described. There. a slidable component carrier I2 supports two components at a time and conveys them to a grinding station where they are transferred electromagnetically to a respective one of a pair of rotary heads [3 for grinding. After a grinding operation. the carrier is withdrawn from the grinding station disengaging the ground components and causing them to be discharged via an unload chute 14 as hereinafter described. Any magnetic residue in the ground components is removed by a demagnetising unit l5 which is located adjacent the chute 14. The carrier is moved to and from by means of pneumatic cylinder 16. An electrical control console 17 is provided on the machine. and incorporates the electrical circuitry required for the automatic operation of the machine as hereinafter described.

Referring to FIGS. 2 to S. the component carrier 12 includes a carriage 20 which is mounted on a dovetail slide 2I carried by a base member 22. The base member 22 is similarly mounted on a frame 23 which forms part of thc grinding machine frame. by means of a sccond do\ ctail slidcnay 24. The base member 22 carries a base plate 25 on which are rotatably mounted the twin rotary heads l3. Thus the base member 22. base plate 25, rotary heads 13 and carrier 12 can be moved relative to the frame 23 along the slide 24. whilst the carrier l2 can also be moved relative to the member 22 along slide 2t.

Movement of base member along slide 24 towards the fixed position of the grinding wheel 2 is effected as a series of incremental steps by means of a second conventional ratchet and pawl device 26 FIG. 2) identical to the device 8. The device 26 includes a screw 27 which, depending on the extent to which it is with drawn from the device. determines the number of ratchet teeth that the pawl (not shown) may cover in one step. Ari override member is provided in the form of a wheel 28 which is arranged to rotate the pawl out of engagement with the ratchet in order that arbitary movement of the member 22 along the slide 24 may be effected. The factors which decide the optimum interval between and the length of successive incremental steps is hereinafter described. Movement of the carrier l2 independently of the member 22 if effected by the pneumatic cylinder 16 of which the piston rod 29 is connected to a pin 30 on the carrier 12.

The load chutes ll are formed as inclined grooves in a plate 3|. the grooves being closed to form a passageway by a backing plate 32 (FIGS. 2 and The

plates

31 and 32 extend into a chamber formed by the carriagc and slide 2t. so that a series of unground components 33 can roll down both the chutes until the foremost component in each chute reaches the loading station indicated at 34 on FIGS. 3 and 4. If the carriage 20 is in its retracted position as shown in FIG. 3, the foremost component 34 in each chute is transferred by means of compressed air passing through passageways 35 through a bore 36 in plate 31 shown in (FIGS. 2 and 5) onto a pair of

shoes

37 and 38 which are adjust-ably mounted onto a plate 39. mounted on the carriage 20 as hereinafter described. The components may be held to the

shoes

37 and 38 by means of small permanent magnets (not shown). Plate 39 is pivotally mounted on carriage 20 by a pivot pin 40 and by bolts M the position of which relative to the plate 39 being adjustable in slots 42 in the plate 39. The plate is adjusted until the axis of the pivot pin 40, the midpoint of a straight line between the axis of two components held on the two pairs of

shoes

37 and 38 and the axis of the grinding wheel lie in the same horizontal plane to ensure accurate grinding.

A pair of magnetic proximity switches 43. which may be either mounted independently from the carriage 20 one adjacent the exit from each chute H as shown. or on the carriage 20. one adjacent each pair of

shoes

37 and 38. are arranged to sense the presence of a compo ncnt on each pair of

shocs

37 and 38. The air supply in passages 35 is then cut off and cylinder 16 is operated to move the carriage 20 rclati\c to the member 22 from the retracted position shown in FIG. 3 to the position shown in l-ltIiS. 2 and 4. i.c.. to the grinding station.

As the carriage 20 reaches the grinding station. it closes a microswitch 44. causing cncrgisation olan electromagnetic circuit 45 thus cncrgising an electromagnetic faceplate 46 on each rotary head l3. liach ol' the two components carried by the

shoes

37 and 38 are attracted into the positions indicated at 47 in engage ment ith a respccthc onc ol'thc heads 13. A motor 48 which in this embodiment is preferably an infinitely variable l)(' drive unit is prmided for continuously rotating the respective spindles 4) of the heads 13 \ia a pulley belt 50. the motor 48 being equidistant from and to one side of the spindles 49 to ensure identical wrap around of the belt 50. The components are thus rotated with the heads. since the electromagnetic faceplates overcome the small magnetic attraction of the small magnets on the

shoes

37 and 38. A further adjustable shoe 51 mounted on the plate 25 is provided adjacent each head 13 to guide the component as it rotates.

At the same time that the electromagnetic circuit 45 is energised, the pivot pin 40 contacts a lever 52 pivotally mounted on the member 22, and the resultant rotation of the lever as the pin 40 continues to advance. produces depression of a spring loaded piston 53 into a dashpot 54. The dash pot thus produces a damping force on the carriage 20. slowing down its movement towards the grinding wheel.

The subsequent slow advance of the carriage 20 under the combined action of cylinder 16 and dashpot 54 causes the

shoes

37 and 38 to push the rotating component across the twin faceplates into contact with the rotating grinding wheel 2. This slow advance of the carriage and the resultant grinding operation on the two components continues for a set period of time depend ing on the size of component until the carriage 20 contacts a pair of adjustable stops 55 on the member 22. Pressure is maintained in cylinder 16 to hold the carriage 20 against the stops 5S fora period of the same duration to spark out.

At the end of this time. a timer 56. previously activated by the microswitch 44 at the same time that the electromagnetic circuit 46 was energised. causes the action ofcylinder 16 to be re\ crsed. retracting the carriage from the grinding station. When the carriage moved away from switch 44. the electromagnetic circuit 45 is dcenergised. releasing the now ground components. which tend to rest on the shoes 5 l. The small permanent magnets on

shoes

37 and 38 atract the component away from the grinding wheel sufficiently for any wheel dig in to be avoided. The ground compo nents then fall under gravity into the unload chute 14. If required, a projection 57 on the end of the plate 39 aids the removal of the components from the shoes 51.

The ground components. such as that at 58 in FIG. 3. roll down the chute 14 passing through the dcmagnetising unit I5. To ensure that the correct size of component is reached. a post process gauging unit t not shown) may be positioned after the demagnetising unit 15 so that any adjustments to the position of stops 55 or to timer 56 can be made where necessary.

The empty carriage 20 continues to retract until it closes a microswitch 59 which causes the cylinder In to bring the carriage to a stop with the shoes 37 anti 38 in the position shovvn in FIG. 3. ready to receive two more unground components from the chutes ll. since the microsvvitch 5') also causes the compressed air supply to pass through passages 35. and hence the cycle is repeated until the pronniity switches 43 tail to sense the presence of any components on the

shoes

37 and 38. i.c. at thc end of a run A counter 6" is arranged to count the number of times that the cylinder to advances the carriage from the loading station to the grinding station. and hence to indicate the number ot components ground lll(iv l l. The number of components llkll can be ground between grinding heel dressing operations can be predetermined. and thus after the et number. the counter is arranged to initiate the simultaneous advance of both the dresser tool and the loading mechanism. i.e.. the member 22 and the carriage together. towards the grinding wheel. the position of which is fixed. to compcnsate for the wearing of the grinding wheel.

Referring to FIGS. 6 and 7, which illustrate diagrammatic views of a loading mechanism capable of presenting one component at a time for grinding. there is shown a slide 70. constituting a slidablc carrier. which at one end is provided with a loading arm 71. The arm 71 has a side wall 710 and shoe supports 72. The arm also has a projection 73 at its extremity.

When the carrier is in a retracted position the shoe supports 72 are at a loading station at the front of a magazine constituted by a tubular chamber 74 in the main body 75 of the machine. The magazine holds a stack 76 of components. The chamber is terminated at its outer end by a tube 77 which rests on the body 75 by means of a flange 78 and has a transverse end wall 79 through which run bores 80 for conveying air pressure from a suitable source to the stack of components in the chamber 74. At an appropriate time when the slidable carrier is retracted the air source is connected to apply pneumatic pressure to the stack in order to drive one component 76a onto the shoe supports. The distance between the side wall 71a of the arm 71, and the mouth 81 of the magazine is such that only one component can be received by the carrier at a time. The carrier 70 when moved forward (i.e., to the right) closes the mouth of the magazine.

In FIG. 7 the carrier in its forward position of the carrier is indicated by the reference 70' When the carrier is in the forward position a component carried on the shoe supports 72 is adjacent a rotary head 82 constituted by an electromagnetic plate which is rotatable about an axis 83 transverse the longitudinal movement of the slider. ()n being atracted to the face 84 of the electromagnetic face plate a component. shown as 76!), is rotated in contact with a grinding wheel 85.

On retraction of the carrier 70 the projection 3 engages the component 76b and pulls it back over the mouth of a chute 86 which slopes away downwardly from the part of the carrier 70.

A typical sequence of events in a grinding cycle using the machines described above is as follows:

After the cessation of grinding of a component. the carrier 70 retracts and in doing so raises the component 76h slightly on the face plate as the shoe supports pass underneath. The clcctro-magnet is switched off and by continued retraction of the carrier 70 the component 76! is drawn off the face plate to a position where it drops by gravity into the unloading chute 86. Substantially simultaneoush with this action. the carrier being by now fully retracted. air is applied to the loading chamber so that a component is blown into position on the shoe supports 72 on the carrier. The carrier is then driven forward to bring the component to the grinding station. A \ei short time before. typically milliseconds bcforc. the component reaches the grinding position. the clcctro-nmgnet is switched on so that the component is drawn into engagement with the drive plate and is rotated thereby The carrier 7" ma) have .i \.iri.|bl controllable feed rate for the last part of its tra el. during which tune the component is being ground l'hcicaflci the sequence itlsl described is repeated as often as necessary til] The loading mechanism of FIGS. 6 and 7 is suitable for use with a similar arrangement of switches. and timer control as described for FIGS. I to 5. and for mounting on a grinding machine similar to that shown in FIG. I, it is possible that instead of a horizontal chamber 74 from which components are blown onto the carrier. the magazine may comprise a vertical chute in which the components are assembled end to end. and from which they are gravity fed onto the carrier.

It will be seen that. essentially, the loading means for the machanisms shown in FIGS. 1 to 5 and in FIGS. 6 and 7 is also the means by which the components are supported whilst being ground, and is also preferably the means by which the components are fed into the grinding wheel.

Means may be provided for directing a jet of air at the component in order to assist its ejection down the unloading chute.

I claim: 1. A loading mechanism for a grinding machine comprising:

a magazine for delivering a series of components to a loading station;

a slidable component carrier;

pneumatic means for applying pneumatic pressure to said series of components to transfer a component at the loading station from the magazine to the carrier;

means for moving the carrier from the loading station to a grinding station;

means on the carrier for receiving said component from the magazine at the loading station and for supporting the component during said movement of the carrier;

a rotary head disposed at the grinding station;

and a controllable magnet positioned for attracting said component from the carrier into engagement with the rotary head for rotation therewith.

2. A mechanism as claimed in claim I, in which the carrier is provided with means for supporting a component peripherally during movement from the loading station to the grinding station.

3. A mechanism as claimed in claim 2, in which the means for supporting comprises at least one supporting shoe.

4. A mechanism as claimed in claim 1, in which the carrier is arranged to withdraw a component from the grinding station. means being provided on the carrier for disengaging the component from the rotary head.

5. A mechanism as claimed in claim 4, in which the controllable magnet is arranged to be activated when the carrier reaches the grinding station and deactivated after a set time interval. the means on the carrier for disengaging a component comprising a projection which is arranged to engage the periphery of the component as the carrier moves away from the grinding station after the controllable magnet is deactivated.

6. A mechanism as claimed in claim 5. in which an unload chute is provided for the removal of a compo ncnt after it has been disengaged from the rotary head.

7. A mechanism as claimed in claim I in which the controllable magnet comprises an electromagnetic faceplate carried b the rotary head.

8. A mechanism as claimed in claim I. in which the pneumatic means includes means for delivering two components at a time by pneumatic pressure from the magaline to the carrier at the loading station.

the loading mechanism further including means on the carrier for receiving two components at a time from the magazine and for supporting the two components during said mmement of the carrier;

two rotary heads disposed at the grinding station;

and a controllable magnet for each head. each magnet being positioned for atracting one of the components from the carrier into engagement with the respective rotary head for rotation therewith.

9. A grinding machine including:

a grinding wheel disposed at a grinding station:

a grinding wheel dresser mechanism adjacent the grinding wheel;

a loading mechanism comprising a magazine for delivering a series of components to a loading station:

a slidable component carrier;

pneumatic means for applying pneumatic pressure to said series of components to transfer a component at the loading station from the magazine to the carrier:

means for moving the carrier between the loading station and the grinding station;

means on the carrier for receiving a component from the magazine at the loading station and for supporting the component during movement of the carrier from the loading station to the grinding station.

a rotary head disposed at the grinding station.

a controllable magnet positioned at the grinding sta- (it l tion for attracting a component from the carrier into engagement with the rotary head for rotation therewith;

and means for advancing the grinding wheel dresser mechanism towards the grinding wheel by a predetermined distance to compensate for grinding wheel wear and for simultaneously advancing the loading mechanism towards the grinding wheel by the same predetermined distance 10. A grinding machine as claimed in claim 9. in which means are provided for feeding the carrier towards the grinding wheel as a variable, controllable rate during the latter part of its movement from the loading station to the grinding station.

ll. A grinding machine as claimed in claim 9. in which the pneumatic means includes means for deliven ing two components at a time by pneumatic pressure from the magazine to the carrier at the loading station;

the loading mechanism further including means on the carrier for receiving two components at a time from the magazine and for supporting the two co mponents during said movement of the carrier;

two rotary heads disposed at the grinding station;

and a controllable magnet for each head. each magnet being positioned for attracting one of the components from the carrier into engagement with the respective rotary head for rotation therewith.

Claims

1. A loading mechanism for a grinding machine comprising: a magazine for delivering a series of components to a loading station; a slidable component carrier; pneumatic means for applying pneumatic pressure to said series of components to transfer a component at the loading station from the magazine to the carrier; means for moving the carrier from the loading station to a grinding station; means on the carrier for receiving said component from the magazine at the loading station and for supporting the component during said movement of the carrier; a rotary head disposed at the grinding station; and a controllable magnet positioned for attracting said component from the carrier into engagement with the rotary head for rotation therewith.

2. A mechanism as Claimed in claim 1, in which the carrier is provided with means for supporting a component peripherally during movement from the loading station to the grinding station.

4. A mechanism as claimed in claim 1, in which the carrier is arranged to withdraw a component from the grinding station, means being provided on the carrier for disengaging the component from the rotary head.

5. A mechanism as claimed in claim 4, in which the controllable magnet is arranged to be activated when the carrier reaches the grinding station and deactivated after a set time interval, the means on the carrier for disengaging a component comprising a projection which is arranged to engage the periphery of the component as the carrier moves away from the grinding station after the controllable magnet is deactivated.

6. A mechanism as claimed in claim 5, in which an unload chute is provided for the removal of a component after it has been disengaged from the rotary head.

7. A mechanism as claimed in claim 1 in which the controllable magnet comprises an electromagnetic faceplate carried by the rotary head.

8. A mechanism as claimed in claim 1, in which the pneumatic means includes means for delivering two components at a time by pneumatic pressure from the magazine to the carrier at the loading station; the loading mechanism further including means on the carrier for receiving two components at a time from the magazine and for supporting the two components during said movement of the carrier; two rotary heads disposed at the grinding station; and a controllable magnet for each head, each magnet being positioned for atracting one of the components from the carrier into engagement with the respective rotary head for rotation therewith.

9. A grinding machine including: a grinding wheel disposed at a grinding station; a grinding wheel dresser mechanism adjacent the grinding wheel; a loading mechanism comprising a magazine for delivering a series of components to a loading station; a slidable component carrier; pneumatic means for applying pneumatic pressure to said series of components to transfer a component at the loading station from the magazine to the carrier; means for moving the carrier between the loading station and the grinding station; means on the carrier for receiving a component from the magazine at the loading station and for supporting the component during movement of the carrier from the loading station to the grinding station. a rotary head disposed at the grinding station; a controllable magnet positioned at the grinding station for attracting a component from the carrier into engagement with the rotary head for rotation therewith; and means for advancing the grinding wheel dresser mechanism towards the grinding wheel by a predetermined distance to compensate for grinding wheel wear and for simultaneously advancing the loading mechanism towards the grinding wheel by the same predetermined distance.

10. A grinding machine as claimed in claim 9, in which means are provided for feeding the carrier towards the grinding wheel as a variable, controllable rate during the latter part of its movement from the loading station to the grinding station.

11. A grinding machine as claimed in claim 9, in which the pneumatic means includes means for delivering two components at a time by pneumatic pressure from the magazine to the carrier at the loading station; the loading mechanism further including means on the carrier for receiving two components at a time from the magazine and for supporting the two components during said movement of the carrier; two rotary heads disposed at the grinding station; and a controllable magnet for each head, each magnet being positioned for attracting one of the components from the carrier into engagement with the respective rotary heaD for rotation therewith.