US3008276A - Abrading machine - Google Patents

Description

Nov. 14, 1961 J. A. KILE 3,008,276

ABRADING MACHINE Filed April 30, 1959 4 Sheets-Sheet 1 Nov. 14, 1961 J. A. KlLE ABRADING MACHINE 4 Sheets-Sheet 2 Filed April 50. 1959 Nov. 14, 1961 J. A. KILE ABRADING MACHINE 4 Sheets-Sheet 4 Filed April 30, 1959 WK W4 M J 0 wwwf 3,608,276 ABRADlNG MAEilNE John A. Kile, St. Cloud, Minm, assignor to Kile Brothers Manufacturing Company, St. Cloud, Minn, a corpora tion of Minnesota Filed Apr. 30, 1955*, Ser. No. 810,170 9 Claims. (Cl. 51-138) This invention relates to abrading machines and more particularly relates to an abrading machine employing a replaceable abrasive or abrading belt.

It has been found advantageous to abrade a surface of a workpiece in such a manner that the abrasive-formed cuts or marks on the surface extend non-linearly. The abrasive cuts or marks are thereby less obvious on the surface, and the surface is likely to be smoother as a result of the method by which the non-linearity of the abrasive cuts is produced.

The non-linearity in the abrasive cuts will be formed by producing relative longitudinal movement produced between the workpiece and belt-mounting head for progressively subjecting various portions of the workpiece to the abrading operation, and additional relative transverse movement between the abrading belt and the workpiece so that one portion of the belt successively engages and abrades areas of the workpiece surface which are disposed in longitudinal and transversely spaced relation from areas previously abraded by this same portion of the belt. The previously mentioned relative transverse movement may be periodically reversed and thereby produce truly non-linear abrasive cuts on the workpiece surface.

Although the formation of non-linear abrasive cuts has been performed in the past, there have been no practical machines adapted for high speed operation which will produce the preferred non-linearity. Previous machines have necessitated substantial movement of high inertia parts for producing the non-linearity in the abrasive cuts and as a result of the high inertia, substantial difficulty has been encountered in producing the necessary rapid movement to effect the relative transverse movement between the workpiece and the abrasive. Furthermore, it has been found that in the rapid movement of high inertia parts, undue strains and stresses are set up which, of course, will cause periodic, if not frequent, shut downs because of mechanical failure.

With these comments in mind it is to the elimination of these and other disadvantages to which the present invention is directed, along with the inclusion therein of other novel and desirable features.

An object of my invention is to provide a new and improved belt-type abrading machine of relatively simple and inexpensive construction and operation.

Another object of my invention is the provision of a high speed abrading machine wherein the abrasive belt is steered in transverse directions by only minute move ment of parts of the machine to thereby effect production of nonlinear abrasive cuts on the surface of the workpiece.

Another object of my invention is the provision of a belt-type high speed abrading machine which is adapted for ready and easy replacement of the abrasive belt.

Still another object of my invention is the provision of an improved and novel belt-type high speed abrading machine wherein the tension in opposite side portions of the belt is carefully controlled and varied to produce steering of the belt toward one side thereof or the other.

A further object of my invention is the provision of a new and novel belt-type abrading machine adapted to sense and limit transverse steering of the belt and to reverse the direction of transverse steering when the belt reaches said limits.

A still further object of my invention is the provision of an improved belt-type high speed abrading machine wherein the pressure roll for holding the abrasive belt against the workpiece is readily and easily replaceable with only a minimum of effort.

These and other objects and advantages of my invention will more fully appear from the following description made in connection with the accompanying drawings wherein like reference characters refer to the same or similar parts throughout the several views. and in which:

FIG. 1 is a general perspective view of the machine in operative condition;

FIG. 2 is a front elevation view of the machine in an enlarged scale as compared to FIG. 1 and shown in operative condition, except that the safety shield or protective housing is removed from the head structure;

FIG. 3 is a top plan view of the machine as shown in FIG. 2 and having portions of the abrasive belt broken away and showing structure therebeneath;

FIG. 4 is a detail section view taken on a generally vertical plane substantially at 4-4 in FIG. 3;

FIG. 5 is a detail section view taken on a generally vertical plane as indicated at 5% in FIG. 4;

FIG. 6 is an enlarged and somewhat exaggerated detail end elevation view of the steering shaft and showing, diagrammatically and in dotted lines, the bearing holders at the opposite ends of the shaft;

FIG. 7 is a view substantially identical. to FIG. 6 except that the shaft is shown oriented in a different position about its rotation axis as contrasted to that shown in FIG. 6.

PEG. 8 is a schematic View of the electrical and air circuitry for controlling the machine;

FIG. 9 is a perspective view of a detailed part of the machine; and

FIG. 10 is a detail section view of a component of the air electrical circuitry.

The abrading machine is indicated in general by numeral 1%) and includes a frame structure 11 having widely spread floor-engaging feet or support portions 11a -md also having an upright rigid standard 11b. The machine also includes a workpiece-supporting structure 12 having an elongate and horizontally oriented frame portion 12a rigidly aflixed at the rear side thereof to an upright slide 12b which is carried for vertical adjustment in ways on the upright standard 1112 and is controlled in its vertical adjustment by means of a crank handle which operates through a suitable gearing mechanism for adjusting the vertical position of the slide. The work support 13 comprises an endless conveyor trained around rollers 14 at the opposite ends of the frame portion 12:: and supporting along its upper run by a steel table 15, a pad 16 which may vary in consistency from a soft sponge rubber to a hardboard, depending upon the nature of the work being performed and which is overlaid with a replaceable tensioned fabric and an anti-friction graphite impregnated garnet paper permitting free sliding movement of the workpiece support or conveyor l3 thereover. It will be understood that the conveyor 13 has an outer surface such that the workpiece will have little tendency to slip when pressed against the surface.

An upright frame plate 12d is aflixed on the slide 1% and mounts a motor 17 which is connected by chain F and sprocket means 18 to the input shaft 19 of gearbox 20, the output shaft 21 of which is connected by a chain and sprocket means 22 to the mounting shaft 23 which is affixed to roller 14 for driving the same. that the workpiece supporting structure 12 is entirely movable upwardly and downwardly on the standard 11b.

The head structure, indicated in general by numeral 24 includes a generally horizontally oriented cantilever beam sesame It will be seen which is, in the form shown, constructed in the form of a box channel of heavy structural steel and which is allixed by a suitable bracket means 25a at its rear end portion to the upright standard 11b. The head structure 24 is provided with an endless or continuous abrading belt 26 having theabrasive surface 26a facing in an outward direction. An important feature of the present invention is the manner in which the belt 26 is mounted to move in a continuous path which circumscribes or encompasses the cantilever beam and all the other belt-mounting and driving and control means such that the belt 26 may be readily and easily removed and replaced by another similar belt.

The belt-mounting and high speed driving means in cludes a plurality of rollers 27, 2S and 29 oriented with generally parallel axes and such as to define a generally triangular continuous or orbital path of movement of the belt 26. The rollers 27 and 28 have peripheral surfaces such as to provide a substantially non-slip relationship with the belt 26, and in the form shown, the rollers 27 and 28 are provided with a plurality of short, outwardly projecting rubber lugs or knobs in closely spaced relation for engaging the belt. The roller 29 is, in the form shown, provided with a plurality of generally spirally extending ribs and grooves on the periphery thereof and the ribs are constructed of hard rubber. The hardness of the peripheral portion of the roller 29 is selected in relation to the nature of work to be done and ing bearings 30a and 31a which mount the roller shaft v29a. The bearing mounts 3t? and 31 are aliixed as by bolts to an adjustable carrier plate 32 which underlies cantilever beam 25 and has a short upstanding pivot post 32a projecting through a corresponding bearing aperture 33 in the bottom of the beam 25. Plate 32 has a pair of slots 32b to receive securing bolts 34 therethrough which ailix the plate 32 in a certain position after adjustment thereof is completed.

The plate positioning or adjusting apparatus includes a pair of spaced cars 35 formed integrally with the plate 32, and a second pair of spaced cars 36 and 37 aflixed to the front portion of the beam 25. An adjusting rod 38 has a threaded end portion 38:; extending through a tapped aperture 37a in the ear3'7 and bearing against the corresponding car 35. The intermediate portion 38b of rod 38 is squared to permit application of a wrench for turning the rod. The otherend portion 33c is round and is extended through a bearing aperture 36a in the car 36 to bear against the ear 35. When bolts 34 are loosened slightly, turning of rod 38 causes movement of plate 32 and roller 29 about the pivot post 32a, in order to align the roller 29 so that transverse belt movement is not effected by this roller.

Means are provided for mounting the rollers 27 and 23 adjacent the top portion of the cantilever beam so as to permit at least limited movement of both end portions of each roll in a direction inwardly and outwardly with respectto the path of movement of belt 26. The head structure 24 is provided'wit'n a pair of cross heads 4%) and 41affixed to and rigid with the cantilever beam 25 and adjacent the outer and inner ends thereof. Each of the cross heads 46 and 41 has a pair of depending and spaced plate portions 40a and 41a respectively and disposed in confronting relation with each other to elfectively define V bifurcated end portions dill) and 41b on the cross heads for receiving and mounting in cooperation with pivots 42 and 43, the swingable bearing mounts 44a and dab, and 45a and 45b. A plurality of bearings 46 are provided in the several bearing mounts 44a, 44b, 45a and 45b and rotatably mount the shafts 47 and 48 of rollers 2.7 and 28 respectively. It will therefore be seen that the opposite ends of the rollers 27 and 28 are movable transversely of their rotation axes and inwardly and outwardly of the orbital path of belt movement when the bearing mounts are swung inwardly and outwardly about the coaxial pivots 42 and the coaxial pivots 43. It should be noted that the pivots 42 and 43 are positioned with respect to the rotation axes of shafts 4'7 and 48 respectively, and with respect to theadjacent runs of the path of the belt so that as the bearing mounts are shifted inwardly and outwardly, the rollers 27 and 28 and their corresponding rotation axes fold inwardly and outwardly along lines which substantially bisect the angle between the adjacent runs or legs of the conveyor belt.

Belt-tensioning and releasing mechanism is connected with the roller 28 through the bearing mounts 45a and 45b thereof to produce simultaneous movement of both ends of the roller in the same direction. Such mechanism includes a rotatably osciilatable shaft 59 journalled in suitable bearings St) on the front and rear cross heads 4%) and 41 and having end portions 490 afiixed as by keying to parallel crank arms 51 which are respectively disposed between the plate portions 43a and 41a of the front and rear cross heads. The crank arms 51 have substantially coaxial bearing apertures 51:: carrying pivot pins 52 which swingably mount connecting rods 53. The connecting rods 53 are threaded at 53a for ctnrying nuts 54 for rigidly, but adjustably securing attachment brackets 55 to the rod. The brackets 55 are swingaoly secured by means of pivots 56 to the respective bearing mounts 45a and 45b.

It will be seen that as the shaft 49 is' oscillated in one direction or the other, the bearing mounts 45a and 455 are simultaneously swung in similar directions inwardly or outwardly with respect to the path of the belt for releasing or tightening the tension on the entire belt and thereby facilitating removal and application of the belt to the rollers over the outer end of the cantilever beam 25 and the other apparatus on the head structure.

Control means are provided for rocking or oscillating the shaft 49 and in the form shown, such control means include a double-acting air cylinder 57 swiugably mounted by means of a pivot 58 and a bracket 59 afiixed to the cantilever beam 25 and disposed in upright position adjacent the shaft 49/ The'piston rod 57a of the air cylinder is swingably connected by means of a pivot 66 to a rocker arm 61 formed integrally with a sleeve 62 which is non-rotatably afiixcd as by set screw to the rocker shaft 49. ends thereof which are connected by means of hoses 57c and 57d to a source of air pressure and additional control mechanism (hereinafter described in connection with the air and electrical control circuitry), so as to produce, with upward movement of the piston, upward movement of the piston rod 57a and upward swinging of the rocker arm else as to rock the shaft 49 in a clockwise direction as seen in FIG. 4, so as to produce outward movement of the bearing mounts and roller 28 to tension the belt.

An additional arm 63 is integral with the sleeve 62 and is secured at its outer end to a tension spring 64, the lower end of which is connected by means of a threaded rod 65 and nuts 66 to the bracket 59 for urging the shaft '49, along with air applied to the top of the cylinder, in a counterclockwise direction When the pressure in the cylinder 57 is relieved and thereby return the roller 28 inwardly into tension-releasing position.

Belt-steering mechanism is connected through the hearing mounts 44a and 2412 to the roller 27 for producing simultaneous, but phased inward and outward movement of the opposite ends of roller 27 for producing a differential between the tensions at the opposite side portions of the belt 26 to thereby effect steering of the belt in directions transverse to the belt and longitudinally of the rollers. Such steering mechanism is indicated in The air cylinder 57 has air inlets 57b at the. I

general by numeral 67 and includes a rocker shaft 68 journalled in suitable bearings 69 on the cross heads 49 and 41 and having reduced camming end portions 68a and 68b respectively projecting into the area between the depending cross head plates 4% and 41a respectively. Rotary bearings 70a and 7% are mounted on the camming end portions 68a and 68b respectively, and are confined within the bearing mounts 71a and 715 respectively which have connecting rods 72a and 72b respectively connected thereto. The connecting rods 72a and 725 are threaded and carry nuts 73 thereon and securing in fixed relation, the brackets 74 which are swingably connected by pivot pins 75 to the respective bearing mounts 44a and 44b respectively. The rocker shaft 68 has a sleeve 76 aflixed thereon as by set screws and a rocker arm 77 having apertures 77a is formed integrally with the sleeve '76 to be oscillated upwardly and downwardly between the positions shown in FIGS. 6 and 7 for rocking the shaft 68.

With particular reference to FIGS. 6 and 7, it will be noted that the camming end portions 63a and 68b of the shaft 68 are eccentrically disposed in relation to the rotation axis of the shaft which is indicated by the point X and it will further be noted that the eccentric cumming end portions 68a and 63b are phased about the rotation axis with respect to each other. In the instant case, the camming end portions 68a and 6812 are phased 180 with respect to each other and are oriented with respect to the direction in which the bearing mounts 71a and 71b are permitted to move so that in the position of the shaft shown in FIG. 6, the bearing mounts 71a has projected the connecting rod 72a forwardly and corresponding bearing mount 44a and the corresponding end portion of roller 27 have been moved in a distance outwardly of the path of the belt. In contrast to the position of bearing mount 71a, the reduced end portion 68b has retracted the bearing mount 71b and the corresponding connecting rods 72b to effect an inward movement of the bearing mount 44b and the corresponding end of roller 27 with respect to the path of movement of belt 26. In FiG. 7, after the shaft 68 has been rotated through an are indicated by the new position of arm 77, the carnming end portions dda and 68b have respectively retracted and projected the corresponding bearing mounts 71a and 71b and have correspondingly moved the opposite end portions of roller 27 out of phase with each other, inwardly and outwardly respectively, with respect to the path of the belt. The inward and outward out of phase movement of the opposite ends of roller 27 causes the tension in the belt to the one side thereof to exceed the tension in the belt to the other side thereof and as a result, the belt will steer in a direction transversely thereof toward the side having reduced tension.

The control means for the steering mechanism 67 to effect reversing of the direction of steering includes a double-acting pneumatic cylinder 8% swingably mounted by means of a pivot 81 and a bracket 82. afiixed -to the cantilever beam 25 and and having the piston rod 80a projecting upwardly and swingably connected by means of a pivot 83 to the rocker arm 77. The air cylinder 80 has air inlet and exhausting ports 84a and 8412 at its upper and lower ends and connected to the hoses 85a and 85b for connecting the air cylinder with the remainder of the control mechanism hereinafter described in connection with the air and electrical circuitry.

The control means for the belt-steering mechanism 6'7 includes a pair of indication-producing belt edge-sensing devices 86 and 37 respectively disposed adjacent the front and rear cross heads 41} and 41 respectively. The devices 86 and 87 include elongate plates 88 having outer end portions 88a overlying the adjacent cross head and also having inner end portions 88b underlying the corresponding side portion of the belt 26. Each of the plates 88 has a mounting arm 89 formed integrally therewith and secured by means of a bolt 9% to the slotted upper horizontal leg 91 of an angle bracket 92, the upright leg 93 of which is slotted and is connected by means of a bolt 94 to the adjacent cross head. By adjusting the bracket 92 vertically with respect to the cross head and by adjusting the mounting arm 89 horizontally with respect to the bracket 92,, the plate 88 may be adjusted to a wide range of positions. Each of the devices 86 and 87 has a hose-attaching air conduit or nipple 95 afixed to the bottom surface of the plate 88 and disposed in air-flow communication and alignment with an air flow opening 96 through the plate 88. Air hoses 97a and 97b are respectively connected to the nipples 95 of the devices 86 and 87 respectively.

Normally, the devices 86 and 87 are adjusted such that the belt 26 will engage and ride over the plates 88, and are also adjusted such that the apertures 96 of the respective devices are spaced apart a distance greater than the width of the belt 26. As the belt is steered in one direction or the other, one of the openings 96 will be exposed and the other opening 96 will be covered by the edge of the belt to close the opening and indications are thereby produced for operating the control means in a fashion hereinafter more fully set forth in connection with the air and electrical circuitry. The spacing between the apertures 96 effectively defines the limits of transverse movement of the belt 26, and when the edge of the belt reaches the limits of its transverse movement the direction of steering is reversed through operation of mechanism 67 and the belt will then be steered in the opposite transverse direction.

It should be noted that all of the air hoses 97a, 97b, 85a and 85b and 57c extend from their corresponding parts rea-rwardly from the head structure 24 to a control panel 98 which is disposed on the upright standard 11 and therefore none of the hoses -will interfere with application of removal of the belt 26.

A motor 99 is mounted on a base plate 100 which is secured by means of a pivot 101 to the top of the standard 11 and is connected by means of pulleys 102 and belts 1G3 in driving relation with pulleys 104 which are secured as by keying on the shaft 48 of the roller 28. The sleeve 100a contains a coiled compression spring which bears against a post 10Gb to continuously urge the motor base plate 109 upwardly. A pneumatic cylinder 1m is anchored on the frame 11 and has its piston rod connected to the base plate 100 for urging the plate 106 upwardly when the piston rod is retracted.

It will be noted that a plane which includes the rotation axes of pulley 102 and shaft 48 is disposed substantially normal to the inward and outward direction of movement of the roller 28 and as a result, there is no substantial loosening or tightening of the belts 103 when the roller 28 is shifted inwardly and outwardly.

Means are provided for holding down the workpiece as it travels along the conveyor 13 and beneath the roller 29 and in the form shown, such means includes a pair of hold-down assemblies 105 and 106 respectively disposed adjacent opposite sides of the roller 29 and each including a workpiece-engaging roller 1417 and being journalled at its opposite ends on swingable arms 108 which are mounted by means of pivots 109 on normally static-nary but adjustable arms 110 which are aflixed to stationary bars 111. The bars 111 are fixed to a bracket plate 112 which is affixed to the cantilever beam 25.

In FIG. 10 is shown a component of the control apparatus for use in connection with the beltsensing apparatus for steering the belt. The housing 113 defines a pair of compartments 113a and 113b having movable diaphrag- ms 114 and 115 respectively therein. The diap-hragrns define chambers 116 and 117 respectively and the diaphragms, which are constructed of flexible material each have a stiffening plate 114a and 115a for movnig the fingers 118 and 119 of pressure-operated switches P1 and P2.

Air under pressure is supplied through a hose 120 and through orifices 121 and 122 into the respective chamber 117 and 116. The chambers 117 and 116 have air flow outlets 123 and 124 which provide no restriction to air flow and which are respectively connected with the hoses 97b and 97a respectively. When pressure is built up in either of the chambers 117 or 116, the corresponding pressure-operated switch P1 or P2, will operate as the fingers 118 or 119 are moved outwardly by means of the diaphragm.

With reference to FIG. 8 which shows the combined air and electrical circuit diagram, air under pressure is supplied from a suitable source at PS through an air filter F to the main pressure line M. Air pressure-regulating and gauge apparatus G is provided between the main air line M and the branch air lines M1 and 120 respectively. The branch line M1 supplies air pressure to a normally open pressure-operated switch P3, which closes when pressure is applied thereto, and also supplies air under pressure to a pair of 4-way valves V1 and V2.

Each of the valves V1 and V2 has a pressure inlet P1 and a pair of exhaust outlets EX. The pressure inlets and exhaust outlets are interchangeably connectible to the air hoses for the pneumatic cylinders. The valves V1 and V2 are operable by means of electric solenoids E1 and E2 respectively. When V1 is in its normal position the pressure inlet is connected to the pressure line 57a! for retracting the piston cylinder 57. When the solenoid E1 has operated valve V1, the pressure inlet is connected through the valve to the hose 57c and 570' for extending cylinder 57 and retracting cylinder 101a, and when operated, valve V1 connects the hose 57d to the exhaust outlets EX. 7

When valve V2 is in its normal position, the pressure inlet P1 is connected to hose 75a for normally extending cylinder 80 and the exhaust outlet EX is connected to the hose 85b. When solenoid E2 has operated valve V2, the pressure inlet P1 is connected with the hose 85b and the exhaust outlet EX is connected with the hose 85a, whereby to retract the piston rod.

In FIG, 8 is also shown the electrical circuitry which is used inconnection with the air circuitry and the line voltage, which may be 220 volts-3 phase-is provided at the terminals L1, L2, L3 and ground GND. The main drive motor 99 is connected-through a magnetic motor starter MMS, of conventional construction, and through lines a, b, c to the power terminals L1, L2 and L3. Conveyor motor 17 is connectible to line terminal L1 through lead on-ofi? switch S2'and lead a. The other side of conveyor motorv 17 is connected to line terminal L2 through lead e, terminal X11, jumper F, terminal X9 and lead b. a

A pair of solenoids E1 and E2 are provided for operating the 4-way valves V1 and V2. Solenoid E1 is connected to terminal L1 by lead a. The other side of solenoid E1 is connectible to the ground terminal GND by lead g, on-otf switch S3 and lead 11. One side of solenoid E2 is conncctible to terminal L1 through lead on-oif switch S1 and lead b. The other side of solenoid E2 is connectible to the ground terminfl GND through lead k, terminal X3, lead I, contact K2b of relay K2, lead m, terminal X13 and lead h. A stepdown transformer T1 is provided for supplying low voltage power for operating the relays K1 and K2. The primary Winding of transformer T1 is connected at one side to the ground terminal GND through lead m, terminal X13 and lead h. The other side of the primary winding of transformer T1 is connectible to terminal L1 through terminal X14, lead 12, on-otf switchSl and lead a. A bridge rectifier BR is connected across the secondary winding of transformer T1 by means of leads 0 and p and the line p has a resistor R1 connected therein. The output from the bridge rectifier BR is provided at leads q and r, and a liltering condenser C1 is connected across the leads r and q. One side of the windings of each of the'relays K1 and K2 is connected directly to the lead r. The other side of relay K1 is connectible to lead q through lead s, terminal X12, lead t, on-ofi switch S4, lead a, normally open pressure sensitive switch P3, lead z, terminal X8 and lead w. The other side of the winding of relay K2 is connectible to lead q through lead x, lead y, normally open pressure-responsive switch P1, lead z, terminal X5 and lead w. A coil discharging resistor R2 is connected across leads x and r.

Relay K2 has a contact K2a serving to hold the relay K2 energized after it is once energized, and the contact K2a is connected to line 2: and is connectible to line q through a, terminal X4, lead b, normally closed pressure responsive switch P2, lead z, terminal X5 and lead w.

Control power is provided to the magnetic motor starter MMS from the terminal L1, through lead c, terminal X7, lead d, relay contact Kla, lead a, terminal X11), lead n, on-oii switch S1 and lead a. The magnetic motor starter MMS has its controls connected to the ground terminal GND through the lead It.

It will be noted that in the circuit shown the stepdown transformer T1 and the bridge rectifier BR and the condenser Cl provide approximately 12 volts DC. for operating the relays K1 and K2.

In the operation of the air and electric circuits shown in FIG. 8, power is applied to the terminals L1, L2 and L3 and air under pressure is applied at PS. The air pressure safety switch P3 is operated to close its contacts and pressure is applied to the cylinder 57 to retract the roller 28 and permit application of the abrasive belt to the head. Pressure is also normally applied to the bottom of cylinder in order that the belt steering mechanism will assume the position shown in FIG. 6 to accomplish rearward steering of the belt. As the belt is applied to the head, the front edge-sensing device 86 will be covered by the belt and outward flow of air through the hose 97a is restricted. The edge-sensing device 87 is left uncovered and air is permitted to freely flow through the hose 97b and out through the sensing device 87 to prevent a build up of pressure in the chamber 117. The belt covering device 86 restricts outward flow of air and therefore pressure builds up in chamber 116 and causes the diaphragm 114 to move outwardly and switch P2 opens, with no immediate elfect.

Under these conditions, the on-oif switch S1 is closed and transformer T1 and the low voltage D.C. circuit is energized.

Subsequently switch S2 is closed and the conveyor motor 17 is energized to move the conveyor belt 13 beneath the head.

Subsequently switch S3 is closed, and power is applied to the solenoid E1 which operates the 4-way valve V1 and causes application of air pressure to the air cylinders 57 and 161a. Cylinder 57 produces a rocking motion of shaft &9 which causes the pulley 2 8 to swing outwardly and apply tension to the abrading belt 26. Cylinder 101a operates to swing the motor base plate upwardly and thereby apply tension to the drive belt 193. The machine is now in condition for operating the high speed drive of the belt 26, and switch S4 is closed which has the efiect of energizing relay K1, causing the contact Kla thereof to close. Closing of contact Kla causes the magnetic motor starter to operate for starting the drive motor 99. When the drive motor 99 is started the abrading belt 26 is moved at high velocity. It was previously pointed out that the steering mechanism including air cylinder 80 is in such a position as to cause the abrading belt 26 to be steered rearwardly along the rollers and along the head. As the rearward steering continues, the front edge-sensing device 86 is uncovered by the belt, whereupon air is allowed to freely fiow outwardly through the hose 97a and the pressure is dropped in the chamber 116 because of the orifice 122 at the air inlet. Diaphragm 114 moves inwardly and pressure switch P2 closes with no immediate eltect. As rearward steering of the belt is continued, it will move into overlying relation with the edge-sensing device 87 and the pressure built up in the chamber 117 results, which causes the diaphragm iii? to move outwardly and close the pressure switch Pi.

When pressure switch Pl closes line :1. is connected to relay K2, which is energized and operated. Contact K'Za establishes a holding circuit through pressure switch P25. Contact K212 energizes solenoid E2; which operates the valve V2 immediately to cause the retraction of the cylinder 8% and operation of the steering mechanism into the position shown in FIG. 7, whereupon, due to the change in the differential tension between the sides of the abrading belt 26, the abrading belt will steer forwardly toward the front end of the rollers and toward the front of the head.

When the edge-sensing device 8'7 is uncovered by the belt, air is allowed to flow freely through the hose 97/2 out of the chamber 117, and a pressure drop occurs in the chamber 117 due to the dew restriction or orifice 123, whereupon diaphragm 115 moves inwardly and pre "15G switch Pl opens with no immediate eifect. The holding circuit through contact KZo and P2 is now in control of relay K2.

As the belt is steered forwardly, edge-sensing device 236 will be subsequently covered by the abrading belt 25 to cause restriction of air flow through the hose We, causing a pressure build up in the chamber 116. Diaphragm lid is moved outwardly to effect opening of pressure switch P2, which breaks the holding circuit for relay K2 causing the contacts of relay K2 to open. Opening of contact KZa provides an additional opening in the hold circuit. Opening of contact K25 deencrgizes solenoid E2, and the spring return on valve V2 causes the valve to return to its normal position, whereupon the air connections to air cylinder 8% are reversed, the piston rod thereof is extended, and the s coring mechanism is operated to assume the position shown in FlG. 6, whereupon the abrading belt 26 is again steered rearwardly.

In order to understand the operation of the Pbrading machine, it is pointed out that the abrading belt 25 will move at speeds in the range of 506- feet per minute. distinct contrast to this, the conveyor belt 13 is moved at a slow speed of only a few feet per minute f r V workpiece under the abrading belt. The abrading bel 26 will oscillate back and forth slightly win. in predetermined limits so that the abrasive cuts on the workpiece form a non-linear pattern. The abrasive cuts on the workpiece actually have a wavy pattern wh ch may approximate the shape of a sine wave. If a particle of metal from the workpiece catches on the belt, the workpiece will not be marked along a straight line, but will be marked, if at all, along a wavy or zig-zag line. Because of the transverse movement of the belt, it has been experienced that most particles are thrown on the belt so that such particles will not mark the workpiece at all. Furthermore, as a result of the transverse oscillation or movement of the belt, it has been experienced t the machine will not load down, as is the tendency when belts of certain types are used.

It should be noted that there is only an absolute minimum of mechanical movement which accompanies the transverse steering of the belt. The shaft 6% is rocked slightly in one direction or the other to produce only a slight relative inward and outward movement of the opposite ends of roller 27 in order to produce the steering.

e magnitude of transverse steering movement of the belt 26 may be easily adjusted by adjusting t1 2 relative positions of the edge-sensing devices as i? in order to increase the magnitude of transverse steering the opening 96 will be moved away from each other, and to decrease the magnitude of transverse steering movement the Openings 96 are moved toward each other.

The rate of movement of the belt a transverse direction depends upon the relative positions of the opposite ends of roller 27, which is controlled by the arc in which the shaft 63 is permitted to turn as the cylinder is operated. If the piston rod of cylinder 8% is connected to the arm 77 at one of the apertures 77a, the rate of transverse movement of the belt will be different than if the connection is at a different aperture 157a.

When the abrading machine is to be shut down the switch Sd is opened, whereupon the relay Kit is cleanergized which causes the contact Kit: to open. This effects a deenergization, by means of the magnetic motor starter MMS of the drive motor By subsequently opening switches 51, S2 and S3, the electric control mechanism is shut down, the workpiece conveyor is stopped and the ter ion is relieved on the abrading belt and also on the drive belt.

It will be seen that l have provided a new and novel high speed abrading machine for producing, through only a of mechanical movement of relatively light weight parts, non-linear or wavy cut marks in the workpiece so as to cause any particles which are caught on the abrading belt to be thrown off and thereby reduce loading of the machine.

it will, of course, be understood that various changes may be made in the form, detail, arrangement and proportion of the parts without departing from the scope of my invention which consists of the matter described herein and set forth in the appended claims.

What is claimed is:

l. A workpiece abrading apparatus comprising a frame, a workpiece support on the frame, a head structure on the frame, means producing relative movement between the head structure and the support one along the other and in a first direction, a continuous abrading belt having opposite side portions, a belt-supporting and driving means on the head structure and including a belt-steering idler roll, a contact idler roll with a rubber belt-engaging periphery, and a belt-tensioning and drive roll, means mounting said contact roll in spaced relation with the workpiece support for guiding the belt into engagement with the workpiece, belt-steering apparatus connected with said steering roll to effect steering of the belt in a direction transversely of said first direction, means mounting the opposite ends of said tensioning and drive roller for inward and outward movement with respect to the path of the belt, means for simultaneously moving the opposite ends of said tensioning and drive roller outwardly to tension the belt, a source of rotary power on the frame and movable means connecting said power source with the tensioning and drive roller.

2. A workpiece abrading apparatus, comprising a frame, a workpiece support on the frame, a head structure on the frame, means producing relative movement between the head structure and the support one along the other and in a first direction and at a first speed, a continuous abrading belt, belt supporting and driving means on the head structure and includin a plurality of beltmounting rollers around which the belt moves in a continuous path, one of said rollers extending across said workpiece support in spaced relation therewith with the rotation axis extending transversely of said first direction for guiding the belt into engaging and abrading relation with the workpiece, a pair of bearings each mounting a respective end of a second of said rollers, a pair of mountings each carrying a respective veering means individually securing said mountings to the head structure adiacent the corresponding ends of the roller for movement transversely of the axis of said second roller, belt-steering mechanism connected with said mountings being operable to oscillate the opposite ends of said second roller in opposite direction, relative to each other, transversely of the axis of the roller to thereby effect steering of the belt, means sensing the transverse position of the belt and operating said steering mechanism in response to the sensed position of the belt, whereby the abrading produces non-linear cut marks on the workpiece.

3. A workpiece abrading apparatus, comprising a frame, a workpiece support on the frame, a head structure aooaavs on the frame, means producing relative 'movement between the head structure and the support one along the other and in a first direction and at a first speed, a continuous abrading belt, belt-supporting and high speed driving means on the head structure and including a plurality of belt-mounting rollers around which the belt moves in a continuous path, one of said rollers extending across said workpiece support in spaced relation therewith and with the rotation axis extending transversely of said first direction for guiding the belt into engaging and abrading relation with the workpiece, a pair of bearings respectively mounting the opposite ends of a second of said rollers and movably mounted on the head structure to permit relative movement of the opposite ends of the second roller in directions transversely of the roller axis, a rotary member having a pair of cams eccentrically related to the rotation axis, means mounting the rotary member for rotary movement adjacent the second roller, a pair of cam followers each interconnecting a respective cam with a corresponding bearing for producing relative movement of the bearings when the rotary member is turned, said cams being phased about the rotation axis of the rotary member to produce movement of the bearings in opposite directions with respect to each other when the rotary member is turned and thereby produce a differential between the tensions on the belt at the opposite side portions thereof and thereby efiiect steering of the belt, and control means operable for turning said rotary member to effect periodic reversing of the direction of steering of the belt, whereby the abrading belt produces non-linear cut marks on the workpiece.

4. A workpiece abrading apparatus, comprising a frame, a workpiece support on the frame, a head structure on the frame, means producing relative movement between the head structure and the support one along the other and in a first direction and at a first speed, a continuous abrading belt having opposite side portions, a beltsupporting and high-speed driving means on the head structure and driving the belt about a continuous path at a second speed substantially greater than first speed, said belt-supporting and driving means including a first roller and a second roller means, said first roller extending across the workpiece support in spaced relation therewith and with the rotation axis extending transversely of said first direction for guiding the belt into engaging and abrading relation with the workpiece, bearing means at opposite sides of the belt and mounting said second roller means for movement inwardly and outwardly with respect to the continuous path of the belt, operable and releasable belt-tensioning mechanism connected with said bearing means and operating to move the same outwardly in phase with each other to simultaneously tension both side portions of the belt, reversible belt-steering mechanism connected with said bearing means and operating to move the same inwardly and outwardly at opposite side portions of the belt out of phase'with each other to produce a differential between the tensions at opposite sides I of the belt and thereby effect transverse steering of the belt, and control means for operating said steering mechanism to elfect'reversing the direction of steering of the belt.

5. A workpiece abrading apparatus, comprising a frame, a workpiece support movably mounted on the frame for movement in a first direction, a continuous abrading belt, a head structure including a generally horizontal cantilever beam secured to the frame, belt-mounting and high speed driving roller means carrying the belt under tension about an upright, unobstructed and continuous orbital path around the beam, a portion of said path being in a direction substantially parallel to said first direction, the workpiece support being disposed in spaced,

but generally tangential relation with said portion of the path to cause the belt to engage and abrade the workpiece, bearing means onthe cantilever beam and disposed inwardly of the continuous path of belt movement and i2 iournalling the roller means adjacent opposite sides of the belt, and movable means connected with the roller means and operable to release tension on the belt, whereby the belt may be applied and removed over the end of the cantilever beam and roller means.

6. A workpiece abrading apparatus, comprising a frame, a generally horizontally oriented workpiece support movably mounted on the frame for movement in a first direction, a continuous abrading belt, a head structure including a generally horizontal cantilever beam secured to the frame, belt-mounting and high speed driving means mounted on the cantilever beam and carrying the belt under tension about an upright and unobstructed continuous orbital path around the beam and around the beltmounting means, a portion of said path being in a direction substantially parallel to said first direction, the beltmounting and driving means including a roller mounting the belt along said portion of the path, the workpiece support being disposed in spaced but generally tangential relation with said roller to cause the belt to engage and abrade the workpiece, said belt-mounting and driving means including additional belt-mounting roller means disposed inwardly of said orbital path and being mounted adjacent opposite side portions of the belt for inward and outward movement with respect to the orbital path, and control mechanism within said path for producing in phase and out of phase inward and outward movement of the additional roller means at opposite sides of the belt for tensioning and releasing the belt and for steering the belt in transverse directions, whereby the belt may be applied over the end of the cantilever beam to the belt-mounting and driving means thereon for producing non-linear abrasive cuts on the workpiece surface.

7. A workpiece abrading apparatus, comprising a frame, a workpiece support on the frame, a head structure on the frame, means producing relative movement between the head structure and the support, one along the other, and in a first direction, a continuous abrading belt having opposite side portions, a belt-supporting and driving means on the head structure and including a belt-steering idler roll, a contact idler roll with a rubber belt-engaging periphery, and a belt-tensioning, and drive roll, means mounting said contact roll in spaced relation with the workpiece support for guiding the belt into engagement with the workpiece, belt-steering apparatus connected with said steering roll to effect steering of the belt in a direction transversely of said first direction, means swingably mounting the opposite ends of said tensioning and drive roller for inward and outward swinging movement about a swing axis, means for simultaneously moving the opposite ends of said tensioning and drive roller outwardly to tension the belt, a source of rotary power on the frame and having a rotary driving element, a rotary drive element, a rotary drive element secured to the tensioning and drive roller, an endless flexible powertransmitting element trained around said rotary drive element for transmitting rotary power to the tensioning and drive roller, the rotation axes of said tensioning and drive roller and of said drive elements and said swing axis all being substantially parallel with each other and lying substantially in a plane when the belt is tensioned.

8. The invention set forth in claim 1 wherein said steering roll has a plurality of outwardly protruding diamondshaped belt-engaging treads on the periphery thereof for producing positive steering of the belt.

9. A workpiece abrading apparatus, comprising a frame, a workpiece support on the frame, a head structure on the frame, means producing relative movement between the head structure and the support one along the other and in a first direction, a continuous abrading belt, belt-supporting and high speed driving means on the head structure and including a contact idler roll positioning the belt such that one portion of the belt engages the workpiece and moves substantially parallel to said first direction at high velocity to abrade the workpiece, a sub- 13 14 stantially fiat mounting plate extending along one side for positioning said plate and contact idler roll at a preof said contact idler roll, bearing means mounted on said determined position about said pivot axis. plate and securing the contact idler roll thereto, interfitting pivot and pivot-receiving means on the head structure References Cited in the file of this patent and plate permitting movement of said plate on an axis 5 extending substantially normal to the rotation axis of UNHED STATES PATENTS said contact idler roll, adjustable means detachably secur- 2,220,268 Olsen Nov. 5, 1940 ing said plate to the head structure and permitting limited 2,597,256 Murray M 20 1952 movement of the plate about said pivot axis, and inter- 2 744 3 3 Gluck May 3 95 engaging adjustable means on the head structure and plate 10 I

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