Method of and apparatus for rapidly and simultaneously abrading metal workpieces in preselected plural numbers

Claim 2

A grinding machine comprising the combination of: A. a turntable having a plurality of work supports positioned to travel in a circular orbit upon rotation of the turntable, there being an even number of said work supports arranged in substantially diametrically opposite pairs with respect to the turntable axis; B. a pair of abrading heads above the turntable at substantially diametrically opposite locations on the circular orbit of the work supports, so that said locations constitute work stations, each of said abrading heads having a power driven endless abrasive belt and a backup member to hold a downwardly facing stretch of the belt against a workpiece on a work support therebeneath; C. means to effect relative motion towards one another between the abrasive belts and the work supports then at the work stations, to thereby produce and maintain work performing engagement between both abrasive belts and the workpieces on said work supports; and D. means for indexing the turntable in increments so related to the orbital distance between the work supports that with each index a pair of opposite work supports is brought to said work stations and another such pair is brought to intermediate stations on the circular orbit of the work supports, so that during the intervals between indexing of the turntable, the two workpieces at the work stations can be ground while loading and unloading of workpieces can take place at at least one of said intermediate statiOns.

Claim 3

The invention defined by claim 1, further characterized in that at one of said abrading heads the endless abrasive belt is trained over three rolls arranged in a triangle, the base of which is horizontal so that two of said rolls are at the bottom of the triangle and the third roll is at the apex thereof, and wherein the backup member for said abrading head is a flat horizontal platen overlying a substantial area of the stretch of the belt extending between the rolls at the bottom corners of the triangle.

Claim 4

movable carrier structure for the backup means; and

Claim 5

movable carrier structure for the backup means; and

Claim 6

variable speed motor means drivingly connected with said jack screw means to operate the same at a selected rate.

Claim 7

variable speed motor means drivingly connected with said jack screw means to operate the same at a selected rate.

Claim 8

control means for said jack screw means by which its screw may be extended or retracted to effect said adjustment of the stop means.

Claim 9

control means for said jack screw means by which its screw may be extended or retracted to effect said adjustment of the stop means.

Claim 10

movable carrier structure for the backup means; and

Claim 11

movable carrier structure for the backup means; and

Claim 12

a retractable stop member, and

Claim 13

a retractable stop member, and

Claim 14

stationary means mounting said stop member for movement between an operative position in the circular path defined by the stop dogs as the turntable turns, to have an advancing stop dog collide therewith and thus arrest further indexing rotation of the turntable, and a retracted position allowing the turntable to continue its indexing rotation; D. yieldable power means to impart indexIng rotation to the turntable and by which, upon engagement of a stop dog with the retractable stop member, the turntable is held firmly against said stop member; and E. controlled power means to momentarily retract the stop member from engagement with a stop dog that has collided therewith, to thereby free said yieldable power means to effect indexing rotation of the turntable to its next position.

Claim 15

stationary means mounting said stop member for movement between an operative position in the circular path defined by the stop dogs as the turntable turns, to have an advancing stop dog collide therewith and thus arrest further indexing rotation of the turntable, and a retracted position allowing the turntable to continue its indexing rotation; D. yieldable power means to impart indexIng rotation to the turntable and by which, upon engagement of a stop dog with the retractable stop member, the turntable is held firmly against said stop member; and E. controlled power means to momentarily retract the stop member from engagement with a stop dog that has collided therewith, to thereby free said yieldable power means to effect indexing rotation of the turntable to its next position.

Claim 16

guide means connecting said two structures and constraining the latter to translatory motion; and wherein said adjustable stop means comprises

Claim 17

guide means connecting said two structures and constraining the latter to translatory motion; and wherein said adjustable stop means comprises

Claim 18

guide means connecting said two structures and constraining the latter to translatory motion; and wherein said rate controlling means comprises

Claim 19

guide means connecting said two structures and constraining the latter to translatory motion; and wherein said rate controlling means comprises

Claim 20

The invention defined by claim 2, wherein the indexing of the turntable is always in the same direction so that workpieces are brought first to one and then the other work station, wherein said abrading head at which the backup member is a flat platen is at said other work station, and the backup member of the abrading head at the first work station is a contact drum, so that at said first work station the abrasive belt engages the workpieces along a narrow linear zone while at said other abrading head a substantial area of the abrasive belt engages the workpieces, wherein the work supports are rotatably mounted on the turntable, and further characterized by: means for rotating the work supports during the time the workpieces thereon are being abraded, so that during operation of the machine workpieces are rough ground by the abrading head with the contact drum as its backup member, and finish ground by the abrading head at which the flat platen provides the backup member.

Claim 21

The invention defined by claim 1, wherein said relative motion between the abrasive belts and the work supports results from downward motion of the backup members, and means for imparting downward motion to the backup members.

Claim 22

The invention defined by claim 4, wherein said means for imparting downward motion to the backup members of the two abrading heads function independently of one another.

Claim 23

An abrading machine comprising: A. a main frame; B. a plurality of spaced apart endless abrasive belts mounted on said main frame for continuous orbital motion along defined paths that include work engaging stretches; C. a plurality of work supporting means, each adapted to releasably carry a workpiece and present the same to each of the work performing stretches of said abrasive belts; D. backup means for each of said endless abrasive belts operative to hold the work engaging stretch thereof against a workpiece in position to be acted upon by its respective abrasive belt; and E. separate power drive means for each of said backup means to effect movement thereof towards the work supporting means in position presenting a workpiece to its associated abrasive belt and thereby force the work performing stretch of the belt into grinding engagement with a workpiece on said work supporting means, said power drive means for the different backup means being independent of one another so that the distances the different backup means move towards said work supporting means need not be the same.

Claim 24

An abrading machine comprising: A. a main frame; B. a plurality of spaced apart endless abrasive belts mounted on said main frame for continuous orbital motion along defined paths that include work engaging stretches; C. a plurality of work supporting means, each adapted to releasably carry a workpiece and present the same to each of the work performing stretches of said abrasive belts; D. backup means for each of said endless abrasive belts operative to hold the work engaging stretch thereof against a workpiece in position to be acted upon by its respective abrasive belt; and E. separate power drive means for each of said backup means to effect movement thereof towards the work supporting means in position presenting a workpiece to its associated abrasive belt and thereby force the work performing stretch of the belt into grinding engagement with a workpiece on said work supporting means, said power drive means for the different backup means being independent of one another so that the distances the different backup means move towards said work supporting means need not be the same.

Claim 25

The abrading machine of claim 6, further characterized by: rate control means operative to govern the rate at which said backup means move towards the work supporting means.

Claim 26

The abrading machine of claim 6, further characterized by: rate control means for each of said power means operative to cause the same to move its respective backup means at a fast rate during the advance of its associated abrasive belt towards the workpiece in position to be acted upon and at a slower rate while the abrasive belt is in contact with the workpiece.

Claim 27

The abrading machine of claim 6, wherein said power drive means for all of said backup means act simultaneously but independently of one another, so that either the same or different work can be performed simultaneously by all of said abrasive belts.

Claim 28

The abrading machine of claim 9, wherein said backup means are movable between defined projected and retracted positions towards and from the work supports, and further characterized by: adjustment means individually operative to adjust the limit to which each of said backup means can be projected, whereby the distance said backup means move the work engaging stretches of their respective abrasive belts towards the work supports and the amount ground off the workpieces by each of the different abrasive belts may be predetermined, and the workpieces being simultaneously acted upon can be ground to different predetermined depths.

Claim 29

An abrading machine comprising: A. a main frame; B. a plurality of spaced apart abrading heads mounted in the main frame, each of said abrading heads having a power driven endless abrasive belt traveling orbitally along a defined path that includes a work performing stretch; C. a frame structure mounted in the main frame for relative translatory movement toward and from said plurality of spaced apart abrading heads; D. a plurality of spaced apart rotatable work supports carried by said frame structure, each of said work supports being adapted to releasably hold a workpiece in position to be abraded by the work performing stretch of the abrasive belt of one of the abrading heads; E. power drive means operatively connected to effect simultaneous rotation of said plurality of work supports and the workpieces thereon; F. power drive means operatively connected to effect simultaneous relative work feeding movement between the work performing stretch of said spaced apart plurality of abrading heads and said work supports, to thereby effect work performing engagement between the rotating workpieces and the orbitally traveling endless abrasive belts; and G. adjustable stop means for selectively and individually limiting relative work feeding movement between the work performing stretch of each of said abrasive belts and said work supports, so that the depth to which the abrasive belts of the different abrading heads cut may be individually predetermined.

Claim 30

An abrading machine comprising: A. a main frame; B. a plurality of spaced apart abrading heads mounted in the main frame, each of said abrading heads having a power driven endless abrasive belt traveling orbitally along a defined path that includes a work performing stretch; C. a frame structure mounted in the main frame for relative translatory movement toward and from said plurality of spaced apart abrading heads; D. a plurality of spaced apart rotatable work supports carried by said frame structure, each of said work supports being adapted to releasably hold a workpiece in position to be abraded by the work performing stretch of the abrasive belt of one of the abrading heads; E. power drive means operatively connected to effect simultaneous rotation of said plurality of work supports and the workpieces thereon; F. power drive means operatively connected to effect simultaneous relative work feeding movement between the work performing stretch of said spaced apart plurality of abrading heads and said work supports, to thereby effect work performing engagement between the rotating workpieces and the orbitally traveling endless abrasive belts; and G. adjustable stop means for selectively and individually limiting relative work feeding movement between the work performing stretch of each of said abrasive belts and said work supports, so that the depth to which the abrasive belts of the different abrading heads cut may be individually predetermined.

Claim 31

The abrading machine of claim 11, further characterized by: adjustable feed rate controlling means for each of said plurality of abrading heads, operative to govern the rate at which its respective abrasive belt cuts into the workpiece being acted upon by it.

Claim 32

An abrading machine comprising: A. a pair of cooperatively disposed supports relatively movable vertically toward and away from one another; B. a plurality of horizontally spaced power driven endless abrasive belts carried by one of said supports to perform different grinding operations; C. a plurality of work supports carried by the other of said supports; D. means connected to move preselected ones of said work supports into vertically aligned and horizontally spaced apart operating positions relative to said abrasive grinding belts; and E. feed drive means connected to move said abrasive belts different vertical distances toward workpieces carried by said preselected work supports in a manner to remove different vertically measured amounts of material from different workpieces.

Claim 33

An abrading machine comprising: A. a pair of cooperatively disposed supports relatively movable vertically toward and away from one another; B. a plurality of horizontally spaced power driven endless abrasive belts carried by one of said supports to perform different grinding operations; C. a plurality of work supports carried by the other of said supports; D. means connected to move preselected ones of said work supports into vertically aligned and horizontally spaced apart operating positions relative to said abrasive grinding belts; and E. feed drive means connected to move said abrasive belts different vertical distances toward workpieces carried by said preselected work supports in a manner to remove different vertically measured amounts of material from different workpieces.

Claim 34

In combination with a roatatable work support adapted to hold a workpiece to be abraded and means for rotating the same: a. a power driven orbitally traveling endless abrasive belt; B. a backup member engaging the back side of said belt; C. first power drive means operable to urge said backup member in a direction to move the portion of said abrasive belt in engagement therewith toward the rotating face of a workpiece on said work support; D. second power drive means selectively operable to so regulate said first power drive means that said backup member initiates a regulated continuous feeding movement of said abrasive belt into direct grinding engagement with the workpiece on said rotating work support; and E. control means selectively operable to regulate the extent of feeding movement controlled by said second power drive means in a manner to selectively control the amount of material removed from a workpiece during an abrasive grinding operation.

Claim 35

In combination with a roatatable work support adapted to hold a workpiece to be abraded and means for rotating the same: a. a power driven orbitally traveling endless abrasive belt; B. a backup member engaging the back side of said belt; C. first power drive means operable to urge said backup member in a direction to move the portion of said abrasive belt in engagement therewith toward the rotating face of a workpiece on said work support; D. second power drive means selectively operable to so regulate said first power drive means that said backup member initiates a regulated continuous feeding movement of said abrasive belt into direct grinding engagement with the workpiece on said rotating work support; and E. control means selectively operable to regulate the extent of feeding movement controlled by said second power drive means in a manner to selectively control the amount of material removed from a workpiece during an abrasive grinding operation.

Claim 36

The invention defined by claim 14, further characterized by: A. hydraulic means connectable to continuously actuate said first power drive means to continuously exert power to actuate said first drive means for movement in the direction to force the abrasive belt into engagement with the workpiece; and B. wherein said second power drive means exerts a preselected restraining or braking action on the operation of said first drive means in a manner that the resultantly combined power effects feeding movement of said abrasive belt at a rate sufficiently reduced to perform a selected grinding operation.

Claim 37

The invention defined by claim 14, further characterized by: A. reversible hydraulic means connectable to first move said first drive means in the direction to bring said backup member to a retracted position relative to the work support; B. means for reversing said hydraulic means for actuating said first drive means for sustained movement in the direction to force said belt into the workpiece; and C. power operable feeding means connected to so actuate said second drive means as to exert a preselected braking action on the operation of said first drive means.

Claim 38

An abrading machine comprising: A. a plurality of horizontally spaced apart power driven abrasive belts, each having a stretch supported by a backup member engaging the back side of said belt; B. a plurality of horizontally spaced apart work supports below the abrasive belts for holding different workpieces to be abraded and for rotating the workpieces about spaced axes that intersect said backup supported stretches of the abrasive belts; C. power drive means operative to independently urge said spaced apart backup members downward and thereby effect grinding engagement of the stretches of the abrasive belts supported thereby with the workpieces that are carried by said horizontally spaced apart work supports; and D. control means presettable to selectively regulate the extent of downward movement of the backup members respectively effected by energization of each of said power drive means.

Claim 39

An abrading machine comprising: A. a plurality of horizontally spaced apart power driven abrasive belts, each having a stretch supported by a backup member engaging the back side of said belt; B. a plurality of horizontally spaced apart work supports below the abrasive belts for holding different workpieces to be abraded and for rotating the workpieces about spaced axes that intersect said backup supported stretches of the abrasive belts; C. power drive means operative to independently urge said spaced apart backup members downward and thereby effect grinding engagement of the stretches of the abrasive belts supported thereby with the workpieces that are carried by said horizontally spaced apart work supports; and D. control means presettable to selectively regulate the extent of downward movement of the backup members respectively effected by energization of each of said power drive means.

Claim 40

The abrading machine of claim 17, wherein said power drive means yieldingly urge their respective backup members downward, and further characterized by feed rate control means operable to govern the rate at which said backup members move downward.

Claim 41

In an abrading machine having a plurality of spaced apart abrading heads, each of which has a power driven orbitally travelling endless abrasive belt and a backup member bearing against a stretch of the belt to define a work performing zone, means for bringing workpieces to be ground to said work performing zones, comprising: A. a turntable mounted to turn about a fixed axis that is equispaced from said work performing zones; B. a plurality of work supporting members mounted on said turntable and so positioned thereon that upon indexed unidirectional rotation of the turntable, workpieces on the work supports are successively presented to said work performing zones; C. stop means for defining the indexed positions of the turntable, said stop means comprising

Claim 42

In an abrading machine having a plurality of spaced apart abrading heads, each of which has a power driven orbitally travelling endless abrasive belt and a backup member bearing against a stretch of the belt to define a work performing zone, means for bringing workpieces to be ground to said work performing zones, comprising: A. a turntable mounted to turn about a fixed axis that is equispaced from said work performing zones; B. a plurality of work supporting members mounted on said turntable and so positioned thereon that upon indexed unidirectional rotation of the turntable, workpieces on the work supports are successively presented to said work performing zones; C. stop means for defining the indexed positions of the turntable, said stop means comprising

Claim 43

The abrading machine of claim 19, wherein said stop dogs are uniformly spaced from one another so that with each index of the turntable, the positional relationship between the work supporting members and the abrading heads is always the same.

Claim 44

The abrading machine of claim 19, wherein said stop dogs are spaced different distances from one another, so that with each index of the turntable the positional relationship between the work supporting members and the abrading heads changes, with the result that the workpieces on the work supporting members contact the abrasive belts at different areas thereof across the width of the abrasive belts.

Claim 45

The abrading machine of claim 19, further characterized in that the stop member is a pin and its stationary mounting means is a sleeve in which the pin slides, and the stop dogs have sockets that open in the direction of indexing rotation of the turntable, and in which the operative end portion of the pin is received as a stop dog collides therewith.

Claim 46

An abrading machine comprising: A. a main frame; B. an abrading head mounted on the main frame and including a power driven endless abrasive belt traveling orbitally along a defined path that includes a work performing stretch; C. work supporting means mounted on the main frame in position to present a workpiece thereon to the work performing stretch of the abrasive belt at a fixed predetermined distance from the abrading head; D. backup means for the work supporting stretch of the abrasive belt; E. means mounting the backup means on the abrading head in position to engage the back of the work performing stretch of the abrasive belt and for movement of the backup means towards and from the work supporting means; F. power means on the abrading head operable to project the backup means towards the work supporting means and thereby force the work performing stretch of the abrasive belt into work performing engagement with a workpiece on the work supporting means; and G. rate controlling means arranged when activated to react between the backup means and the abrading head to oppose said power means and govern the rate at which projection of the backup means towards the work supporting means can take place.

Claim 47

An abrading machine comprising: A. a main frame; B. an abrading head mounted on the main frame and including a power driven endless abrasive belt traveling orbitally along a defined path that includes a work performing stretch; C. work supporting means mounted on the main frame in position to present a workpiece thereon to the work performing stretch of the abrasive belt at a fixed predetermined distance from the abrading head; D. backup means for the work supporting stretch of the abrasive belt; E. means mounting the backup means on the abrading head in position to engage the back of the work performing stretch of the abrasive belt and for movement of the backup means towards and from the work supporting means; F. power means on the abrading head operable to project the backup means towards the work supporting means and thereby force the work performing stretch of the abrasive belt into work performing engagement with a workpiece on the work supporting means; and G. rate controlling means arranged when activated to react between the backup means and the abrading head to oppose said power means and govern the rate at which projection of the backup means towards the work supporting means can take place.

Claim 48

The abrading machine of claim 23, wherein the backup means is at all times in engagement with the back of the work performing stretch of the belt.

Claim 49

The abrading machine of claim 23, wherein the backup means has a defined retracted position in which the backup means is spaced from the back of the work performing stretch of the abrasive belt.

Claim 50

The abrading machine of claim 23, further characterized by adjustable stop means to limit the projection of the backup means towards the work supporting means; and means for adjusting said stop means, whereby the depth to which the workpiece is ground may be selectively fixed.

Claim 51

The abrading machine of claim 26, wherein said power means retracts as well as projects the backup means.

Claim 52

The abrading machine of claim 27, wherein said power means is a hydraulic jack with a fixed stroke, and wherein the retracted position of the backup means is fixedly defined by the bottoming of the retraction stroke of the hydraulic jack.

Claim 53

The abrading machine of claim 23, wherein the rate controlling means is adjustable with respect to the point in the projection of the backup member at which the rate controlling means if activated, and means for effecting such adjustment.

Claim 54

The abrading machine of cLaim 23, wherein the means for mounting the backup means comprises:

Claim 55

The abrading machine of claim 23, wherein the means for mounting the backup means comprises:

Claim 58

A grinding machine comprising the combination of: A. a turntable having a plurality of work supports arranged to travel in a circular orbit upon rotation of the turntable; B. a pair of separate and independent abrading heads above the turntable at circumferentially spaced locations on the circular orbit of the work supports, so that said locations constitute work stations, each of said abrading heads having a power driven endless abrasive belt and a backup member to hold a downwardly facing stretch of the belt against a workpiece on a work support therebeneath; C. means independent of one another to effect relative motion towards one another between the backup members of the two abrading heads and the work supports then at the work stations, to thereby produce and maintain work performing engagement between both abrasive belts and the workpieces on said work supports; and D. means for indexing thE turntable in increments so related to the circumferential distance between the work supports that with each index two of said work supports are brought to said work stations and another work support is brought to an intermediate station on the circular orbit of the work supports, so that during the intervals between indexing of the turntable, the two workpieces at the work stations can be ground while loading and unloading of workpieces can take place at said intermediate station.

Claim 59

A grinding machine comprising the combination of: A. a turntable having a plurality of work supports arranged to travel in a circular orbit upon rotation of the turntable; B. a pair of separate and independent abrading heads above the turntable at circumferentially spaced locations on the circular orbit of the work supports, so that said locations constitute work stations, each of said abrading heads having a power driven endless abrasive belt and a backup member to hold a downwardly facing stretch of the belt against a workpiece on a work support therebeneath; C. means independent of one another to effect relative motion towards one another between the backup members of the two abrading heads and the work supports then at the work stations, to thereby produce and maintain work performing engagement between both abrasive belts and the workpieces on said work supports; and D. means for indexing thE turntable in increments so related to the circumferential distance between the work supports that with each index two of said work supports are brought to said work stations and another work support is brought to an intermediate station on the circular orbit of the work supports, so that during the intervals between indexing of the turntable, the two workpieces at the work stations can be ground while loading and unloading of workpieces can take place at said intermediate station.

Claim 60

The grinding machine of claim 33, wherein at one of said work stations the abrading head does rough grinding and at the other the abrading head does finish grinding; and wherein the direction in which the turntable is indexed brings a workpiece from said intermediate station sequentially to said rough grinding and then said finish grinding stations.

Claim 61

The invention defined by claim 33, wherein said relative motion between the abrasive belts and the work supports results from downward motion of the backup member, and means for imparting downward motion to the backup member.

Claim 62

The invention defined by claim 35, wherein said means for imparting downward motion to the backup members of the two abrading heads function independently of one another.

Claim 63

The invention defined by claim 33, wherein the backup member of at least one of said abrading heads is a flat platen.

Claim 64

The invention defined by claim 34, wherein the backup member of the abrading head that does the rough grinding is a contact drum and the backup member of the abrading head that does finish grinding is a flat platen.

Claim 65

The invention defined by claim 34, wherein there are four work supports on the turntable, and wherein said work stations are substantially diametrically opposite with respect to the axis of the turntable.

Claim 66

The invention defined by claim 33, wherein said relative motion towards one another between the abrasive belts and the work supports is effected by power drive means for each abrading head operative to force its backup member towards the work support therebeneath; and further characterized in that the rate at which said power drive means forces its associated backup member towards the work support therebeneath is controllable; and means for maintaining said rate constant at a preselected value regardless of discontinuity in the surface of the workpiece being ground.

Claim 67

A surface grinding machine comprising the combination of: A. a plurality of separate and independent abrading heads, each having a power driven endless abrasive belt; B. a plurality of work supports adapted to have workpieces secured thereto with the surface thereof that is to be ground positioned for presentation to the abrading heads; C. means operatively connected with the work supports to simultaneously bring one of the same into cooperative relationship with each of the abrading heads; D. a backup member to hold the abrasive belt of a first one of said abrading heads in engagement with a workpiece surface presented thereto, with the contact between the belt and the workpiece limited to a narrow zone extending transversely across the belt; E. a backup member to hold the abrasive belt of a second one of the abrading heads in area-wide flat grinding engagement with a workpiece surface presented thereto; and F. means independent of one another to effect relative motion through selected distances towards one another between the backup members of the abrading heads and the work supports in cooperative relationship therewith, to thereby produce and maintain the aforesaid narrow linear zone of contact between the workpiece surface and the abrasive belt at said first identified abrading head while at said second identified abrading head the abrasive belt is held against the surface of the workpiece thereat with the aforesaid area-wide flat grinding engagement.

Claim 68

A surface grinding machine comprising the combination of: A. a plurality of separate and independent abrading heads, each having a power driven endless abrasive belt; B. a plurality of work supports adapted to have workpieces secured thereto with the surface thereof that is to be ground positioned for presentation to the abrading heads; C. means operatively connected with the work supports to simultaneously bring one of the same into cooperative relationship with each of the abrading heads; D. a backup member to hold the abrasive belt of a first one of said abrading heads in engagement with a workpiece surface presented thereto, with the contact between the belt and the workpiece limited to a narrow zone extending transversely across the belt; E. a backup member to hold the abrasive belt of a second one of the abrading heads in area-wide flat grinding engagement with a workpiece surface presented thereto; and F. means independent of one another to effect relative motion through selected distances towards one another between the backup members of the abrading heads and the work supports in cooperative relationship therewith, to thereby produce and maintain the aforesaid narrow linear zone of contact between the workpiece surface and the abrasive belt at said first identified abrading head while at said second identified abrading head the abrasive belt is held against the surface of the workpiece thereat with the aforesaid area-wide flat grinding engagement.

Claim 69

The invention defined by claim 41, wherein the abrasive belt of the abrading hEad at which the backup member is a flat platen is trained over three rolls arranged in a triangle, the cylindrical surfaces of two of which are tangent to a plane that is perpendicular to the axis about which the work support in cooperative relation with said abrasive belt rotates, and wherein said flat platen overlies a substantial area of the stretch of said abrasive belt extending between said two rolls.

Claim 70

A grinding machine comprising the combination of: A. a turntable having four work supports thereon positioned to travel in a circular orbit upon rotation of the turntable, said work supports being arranged in substantially diametrically opposite pairs with respect to the turntable axis; B. a pair of abrading heads above the turntable at substantially diametrically opposite locations on the circular orbit of the work supports, so that said locations constitute work stations, each of said abrading heads having a power driven endless abrasive belt and a backup member to hold a downwardly facing stretch of the abrasive belt against a workpiece on a work support therebeneath; C. power drive means for the backup member of each abrading head to effect movement thereof towards the work support in position presenting a workpiece to its associated abrasive belt and thereby force the work performing stretch of the belt into grinding engagement with a workpiece on said work support, said power drive means for the backup members of the two abrading heads being independent of one another, so that different amounts of stock can be removed from a workpiece successively presented to the two abrading heads; D. means for indexing the turntable in increments so related to the orbital distance between the work supports that with each index one of said pairs of work supports is brought to said work stations and the other pair is brought to intermediate stations on the circular orbit of the work supports, so that during the intervals between indexing of the turntable, the two workpieces at the work stations can be ground while loading and unloading of work pieces can take place at at least one of said intermediate stations; and E. adjustable means for limiting the distance said power drive means effects movement of the backup member of each abrading head towards the work support therebeneath, so that the distance the backup members are moved towards the work supports may be the same or alternately different with the successive presentation to the abrading heads of the workpieces on the two pairs of work supports.

Claim 71

A grinding machine comprising the combination of: A. a turntable having four work supports thereon positioned to travel in a circular orbit upon rotation of the turntable, said work supports being arranged in substantially diametrically opposite pairs with respect to the turntable axis; B. a pair of abrading heads above the turntable at substantially diametrically opposite locations on the circular orbit of the work supports, so that said locations constitute work stations, each of said abrading heads having a power driven endless abrasive belt and a backup member to hold a downwardly facing stretch of the abrasive belt against a workpiece on a work support therebeneath; C. power drive means for the backup member of each abrading head to effect movement thereof towards the work support in position presenting a workpiece to its associated abrasive belt and thereby force the work performing stretch of the belt into grinding engagement with a workpiece on said work support, said power drive means for the backup members of the two abrading heads being independent of one another, so that different amounts of stock can be removed from a workpiece successively presented to the two abrading heads; D. means for indexing the turntable in increments so related to the orbital distance between the work supports that with each index one of said pairs of work supports is brought to said work stations and the other pair is brought to intermediate stations on the circular orbit of the work supports, so that during the intervals between indexing of the turntable, the two workpieces at the work stations can be ground while loading and unloading of work pieces can take place at at least one of said intermediate stations; and E. adjustable means for limiting the distance said power drive means effects movement of the backup member of each abrading head towards the work support therebeneath, so that the distance the backup members are moved towards the work supports may be the same or alternately different with the successive presentation to the abrading heads of the workpieces on the two pairs of work supports.

Claim 72

The grinding machine of claim 43, further characterized by rate control means operative to govern the rate at which said backup members are moved towards the work supports.

Claim 73

In an abrading machine having a plurality of spaced apart abrading heads, each of which has a power driven orbitally travelling endless abrasive belt and a backup member bearing against a stretch of the belt to define a work performing zone, means for bringing workpieces to be ground to said work performing zones, comprising: A. a turntable mounted to turn about a fixed axis that is equispaced from said work performing zones; B. a plurality of work supporting members mounted on said turntable and so positioned thereon that upon indexed unidirectional rotation of the turntable, workpieces on the work supports are successively presented to said work performing zones; and C. stop means for defining the indexed positions of the turntable with each such position different from the rest with respect to the width of the abrasive belts so that workpieces on the work supporting members contact the abrasive belts at different areas thereof across the width of the abrasive belts.

Claim 74

In an abrading machine having a plurality of spaced apart abrading heads, each of which has a power driven orbitally travelling endless abrasive belt and a backup member bearing against a stretch of the belt to define a work performing zone, means for bringing workpieces to be ground to said work performing zones, comprising: A. a turntable mounted to turn about a fixed axis that is equispaced from said work performing zones; B. a plurality of work supporting members mounted on said turntable and so positioned thereon that upon indexed unidirectional rotation of the turntable, workpieces on the work supports are successively presented to said work performing zones; and C. stop means for defining the indexed positions of the turntable with each such position different from the rest with respect to the width of the abrasive belts so that workpieces on the work supporting members contact the abrasive belts at different areas thereof across the width of the abrasive belts.

Claim 75

The surface grinding machine of claim 41, wherein there are two abrading heads, and wherein at said first identified abrading head the backup member is a contact drum and at said second identified abrading head the backup membeR is a flat platen.

Claim 76

The surface grinding machine of claim 46, wherein said means for simultaneously bringing said work supports into cooperative relationship with the abrading heads comprises a turntable mounted to turn about a vertical axis that is equispaced from the abrading heads, wherein the abrading heads are positioned above the turntable at substantially diametrically opposite sides of the turntable axis; wherein the work supports, of which there are more than the number of abrading heads, are mounted on the turntable at substantially equiangularly spaced locations, and further characterized by: means for indexing the turntable in increments so related to the angular distance between the work supports that upon securement of a workpiece to a work support not in position at an abrading head, while two other work supports are cooperatively positioned at the abrading heads, that workpiece can be successively presented to the abrading heads without being removed from the work support.