US2073786A

US2073786A - Polishing machine

Info

Publication number: US2073786A
Application number: US642478A
Authority: US
Inventors: Doutt Owen
Original assignee: CG Spring and Bumper Co
Current assignee: CG Spring and Bumper Co
Priority date: 1932-11-14
Filing date: 1932-11-14
Publication date: 1937-03-16
Anticipated expiration: 1954-03-16

Description

March 16, 1937. o. DOUTT POLISHING MACHINE 5 Sheets-Sheet 1 Filed NOV. 14, 1932 ZZ El March 16, 1937. O DOUTT 2,073,785

POLISHING MACHINE Filed Nov. 14, 1932 5 Sheets-Sheet 2 Z E YEIF 022/672 Dog/z.

March 16, 1937. o, DC JUTT POLISHING MACHINE Filed Nov. 14, 1932 5 Sheets-Sheet 5 Owe would Mar ch 16, 1937. DOUTT 2,073,786

POLISHING MACHINE Filed Nov. 14, 1932' 5 Sheets-Sheet 4 lllllllllll 9 %ZL J v IIIIIJIWI ,0 8X E- (9. 81

Ola/6% Dow/t March 16, 1937. DOUTT 2,073,786

POLISHING MACHINE Filed Nov. 14, 1932 5 Sheets-Sheet 5 v 43 z .Z/EFVYQJQ" Ozueva Doze/J,

Patented Mar. 16, 1937 UNITED STATES PATENT OFFICE POLISHING MACHINE .0wen Doutt, Detroit, Mich, assignor toGeneral Spring Bumper Corporation, Detroit, Mich.,a corporation of Michigan Application November 14, 1932, Serial No.'642,478 '7 Claims. (Cl. 51-38) Tlhld invention has to do with machines for which it is possible for the wheel to move axially polishing or. grmding work such as bumper bars while it is rotating and thereby follow the irregand has for one of its essential objects to provide ularities and offset edgesin the bar which is being r a machine of this character for grinding bumper ground.

bars of irregular or offset contour. Another object of theinvention resides in the In 'the course of rolling, bending and heat provision of a machine of this character includt eatment to which bumper bars are subjected ing means for positioning a plurality-of polishing preliminary to the grinding and polishing. operwheels at different heights and in different planes 1 atlons, at least one edge of practically every bar in operative relation to the bars to be polished,

0 becomes somewhat .uneven. In grinding bars for simultaneous engagement with the bar. which have plane impact surfaces, and whose A further object of the invention resides in the edges do not include substantially offset or bent provision of .a polishing machine for bumper portions, no diihculty is ordinarily'encountered bars embodying means cooperating with the bar r since the grinding wheel used in grinding such forproperly positioning a plurality of polishing 10 bars has a grinding face of such width that the wheelsin simultaneous operative relation to the i5 entire "surface to be ground lies between the bar. planes ofthe sides of the wheel. Where, how- Another object of the invention resides in the "ever,the impact surface of the bar is transverseprovision of a polishing machine including means ly crowned crctherwise non-rectilinear, and its for affording the positioning of a polishing wheel edge or edges are irregular, considerable difiiculat different elevations and in different planes 20 ty arises since the rigid mounting. of the grindaccording as'the surface of the bar to be ground ing wheel makes it impossible for the wheel, or polished is vertically inclined and includes whose grinding face in such case is correspondlaterally offset portions. mgly' transversely shaped, to follow the irreg- It is still a further object of the invention to V ular1ty even.though the latter is very slight. provide a machine of this character which em- 5 Oftentlmes heretofore when three or more wheels bodies acarrier for the Work to be pol sh d, the operated" simultaneously on a bar such as one carrier being provided'with means cooperating with edge irregularities and transversely crowned, with'means movable with the polishing Wheel for for example, even where the bar was mounted prop r y positioning h Wheel at different for slight lateral play, some portions of the vations and in different planes in accordance with 30 crowned or like surface and of the edges of the the location of the surface to be ground or bar were ground less than others, and some not polished. at all, and a defective bar was produced. Another object of the invention consists in Numerous bumper designs in vogue .at present the provision of a polishing wheel and a prime require flat and crowned or other non-rectilinear mover therefor, t e t being so connected that 35 bars, portions of which are substantially offset or the po is Wheel iS capable of being Positioned .bent edgewise. In the case of flat bars the grindat different distances from the prime mover while ing could be effected by employing wheels of sufthe polishing wheel is being driven therefrom.

1 ficient width. but their initial cost and upkeep Another object of the invention involves the would be prohibitive. With a crowned orlike provision of a'flexible coupling between a polish- 40 surface, as we have seen, grinding of the offset ing wheel and its prime mOVBI, d means i portions with grinding machines heretofore in dependent-of these parts for automatically caususe cannot be effected. The edgewise offset -por-' ing the wheel to be positioned .at different distions of the flat and crowned surfaces to be tances from .the p e-m v r h le the same is ground have heretofore been ground by hand being driven thereby. 5 in conjunction with agrinding wheel. This has It is also -.an object .ofthe invention to proinvolved great expense in the manufacture of vide in a flexible coupling between a polishing each bar. wheel and its prime mover, instrumentalities for Itis accordingly an essential object of the inyieldably holding the:polishing wheel in its outervention toprovide means by which it is possible most position relative to the prime mover. 50 for the grinding wheel to follow the irregularities Inaccordance with thegeneral features of one and offset edges of a piece of work such .as a form of the invention, there is provided a conbumperbar. veyor provided with resilient supports for the It is another object of this .invention to provide endsof a bumper bar whereby the. surface to be a floating mounting for a grinding wheel by polished is positioned uppermost. 'A template is arranged to travel with the conveyor and is provided with one or more laterally offset portions according as the part to be ground is provided with laterally offset or displaced portions. A polishing machine frame is provided in cooperative relation to the conveyor and carries for vertical displacement therealong a plurality of motor-polishing wheel units, one or more of which may be arranged for cooperation with the same template. A flexible coupling between each motor and its cooperating polishing wheel affords relative axial movement therebetween, and a follower arranged for movement with the mounting for the polishing wheel is spring pressed toward and into engagement with the template so that the latter moves the polishing wheel into different planes in accordance with the lateral offset of the diiferent portions of the bar.

In another form, the wheel is mounted to float freely in both directions axially between limits determined by the maximum lateral extent of the transversely crowned or other impact surface of a bar whose edges are not substantially offset but at least one of whose edges is irregular.

With this construction, it is possible to maintain the polishing wheel in operative relation to the entire surface of the bar to be ground with out the need of manual and time-wasting effort for shifting either the polishing wheel into a diiferent plane for engagement with correspondingly oifset portions of the bar, or shifting the bar to position an offset portion of a surface thereof into a position to be ground by the polishing wheel. This shifting of the polishing wheel is automatic and requires no attention whatever, and this construction may be built at a low cost of manufacture.

Further objects and advantages of the invention will appear as the description proceeds.

This invention (in preferred forms) is illustrated in the drawings and hereinafter more fully described.

On the drawings:

Figure 1 is a fragmentary front view of a polishing machine constructed in accordance with the principles of the present invention.

Figure 2 is an end view of the structure shown in Figure 1, looking from the right, certain portions including the conveyor belt being shown in section.

Figure 3 is a longitudinal sectional View taken approximately in the planes indicated by the line III-III in Figure 1, certain parts being shown fragmentarily.

Figure 4 is a sectional view taken approximately in the plane indicated by the line IV-IV in Figure 3.

Figure 5 is a sectional view taken substantially in the plane indicated by the line VV in Figure 3, showing a portion of the conveyor belt.

Figure 6 is a longitudinal sectional view taken substantially as indicated by the line VI-VI in Figure 2, showing a flexible shaft coupling, the shafts being illustrated fragmentarily.

Figure 7 is a sectional View taken substantially in the plane designated by the line VII-VII in Figure 2.

Figure 8 is a fragmentary elevation of a modified floating grinding wheel mounting.

Referring now more particularly to the drawings, the machine comprises a frame work including a plurality of stanchions l arranged in tandem beside a conveyor belt 2 which is preferably endless and travels over pulleys 3 having a suitable source of power (not shown). A table or apron 4 is secured to the stanchions and extends substantially throughout the length of the machine for supporting the portion of the belt which is uppermost as shown in Figure 2. Each stanchion l carries a motor-polishing wheel unit 5 including a motor 6 having a driving shaft 7 and a grinding wheel 8 having a driven shaft 9, the two shafts being connected through a flexible coupling If] for relative axial movement Without disturbing the driving relationship therebetween. Each of these units is carried by a support i l including the rods l2 and 13 which are slidable vertically in bearings carried stationarily by the stanchion or main frame, the rod l2 having upper and lower bearings M and i5 and the rod :3 having the lower bearing IS.

The slide rod l2 projects upwardly through the bearing l4 and carries at its upper end a sleeve I! provided with an arm l8 which is tapped to receive a threaded adjusting member l9. The member I9 is engageable at its lower end with the top of the stanchion l to limit the downward movement of the motor-grinding wheel unit support I I, and obviously the mem ber 19 may be adjusted to vary the extent of vertical movement thereof.

The support H is secured to the rod l2 at its lower end by means of a sleeve 20 which is counterbored at 2| to receive the upper end of the bearing sleeve I 5, and bracket means 22 associated with the grinding wheel head 23 is secured to the intermediate portion of the rod' 12 by bolts. The support H is provided with a second sleeve ing sleeve IS in exactly the way in which the previously described sleeve 20 cooperates with the bearing sleeve l5, and is of substantially the same construction. The support H is further provided with an upper sleeve 24 which is suitably secured to the upper end of the rod l3. The grinding wheel head 23 includes axially stationary and relatively movable parts, and it is the axially stationary part 41 which is secured through the bracket means 22 to the rod l2.

In order that the pressure which is exerted by the grinding wheel 8 upon the bar to be ground due to the weight of the motor-grinding wheel unit and its support ll may not be excessive, the latter are counterbalanced. To this end, a bracket 25 is secured to the stanchion I and pivotally carries a bar 25 intermediate the ends of the latter. One end 27 of the bar 25 has a loose pivotal connection with an adjustable rod 28 depending from the support H, and on the other part of the arm 26 are provided stationary and adjustable counter weights 29 and 30, respectively, whereby the weight of the unit If and the parts carried thereby is largely overcome. It has been found advantageous to so counterbalance the parts as to provide a pressure of approximately 15 pounds of the grinding wheel 8 upon the bar to be ground, but it is obvious that the pressure may be varied as desired.

The bar to be ground may be supported in any suitable fashion, the method herein disclosed being presented for illustrative purposes only. As here shown, yieldable brackets 31 are spaced apart in accordance with the length of the bar to be ground and are secured through an intermediate plate 32 to the conveyor 2 in position to receive the ends of the bar to which said brackets are temporarily secured as at 33. The ends of the bumper bar are here shown as rounded,

20 which cooperates with the bear- 5 and cooperating portions of the brackets 3i cor- 75 respondingly shaped, but it will be understood that this is for illustrative purposes only since the invention hereinaftenmore fully described may be practiced regardless ofthe form which the ends of the bar andthe' corresponding portions of the brackets supporting the same may take. While the brackets '3l may be rigid, they are preferably made of leaf springs or otherwise constructed to provide resilient supports for the ends of the bumper bar.

The flexible coupling is providing forrelative axial movement between the motor shaft 1 and grinding wheel head shaft 9 is shown in detail in Figures 6 and 7. This structure comprises a tube 34 provided at one 'end with a liner 35 which is securely held therein by any suitable means such as'dowels 38. The liner 35 is keyed at 31 tothe motor shaft i so that there can be no relative axial movement between the tube 34 and. the shaft 1. The remainder of the tube 34 is provided with a pluralityof preferably equally spaced longitudinal internal grooves '38 constituting outer races for a corresponding number of series of bearing balls 39. The tube 34 slidably accommodates a bearing sleeve 48 provided with a plurality of longitudinal externalgrooves 4| for registering with the grooves 38. The grooves 4| provide inner races for the balls 39. End caps in the form of ring-like members 42 are formed with external contours corresponding with the internal contour of the tube 34 and thereby provide end closures for the cylindrical spaces provided by each pair of registering grooves 38 and 4|. The end caps 42 are securely fastened tothe ends of the sleeve by screws 43 or the like. The balls 39 are separated from each other by suitable rings 43a arranged for a slidable lit in the registering grooves 38 and 4|. There is thereby established a substantially frictionless spline-connection between the tube 34 and the sleeve 48 and associated parts. 7

A ring shaped end cap 44 is securely fastened to that end of the tube 34 opposite the liner'35 by screws or any other suitable means (not shown). The caps 42, the sleeve 49, and the liner 35 are bored centrally at 45 to substantially the same diameter to receive the respective shafts 9 and 1, the grinding wheel shaft 9 being keyed at 46 to the bearing sleeve 49. Thus regardless of the position of the shaft 9 relative to the shaft 1 therewill at all times be a driving relation therebetween.

The grinding wheel head is designated generally by the numeral 23 and is supported by a sleeve 47 which carries the bracket 22 by means of which the same is mounted on and supported by the slide rod I2. A tubular member 48 is mounted for rotation relative to the grinding head shaft 9 by means of bearings 49 and 54 which are spaced apart on the shaft 9 by means of a sleeve 5|. The ends of the tube 48 are counterbored for accommodating the bearing structures, thereby providing shoulders 52 and 53. An oil shield 54 is positioned in engagement with the shoulder 52 on one side and a face of the outer race of the bearing 49 on the other side, the opposite face of the bearing 49 at the inner race engaging a collar 55 on the shaft 9, thereby positioning the bearing 49. A bearing retaining ring 56 is arranged outwardly of the bearing 49 and is provided with an outwardly extending flange 51 which engages the adjacent end 58 of the tube 48 and extends therebeyond. A-dust guard 59 is secured at 68 to the flange 51 and extends substantially cylindrically in coaxial relationto the: shaft 9 and sleeve 48.

i The bearing is received in a bearing holder 8| which fits in the other counterbore of the sleeve with a press fit. and engages the shoulder 53. The shaft 9' isthreaded at 62 to receive a bearing. retainer nut 63 by which the bearing 58 is heldin engagement with theisleevetl. The

jouter race of the bearing 50 is properly positioned and .held in place by virtue of the cooperation betweenthe bearing retaining ring 64 and the bearing holder (it, the two parts being secured together as shown at 85. The sleeve 48 is thus journalled about the shaft 9 but is held against axial movement relative to the shaft 9.

The tube 48 is provided with a. plurality of preferably equally spaced longitudinal substantially' V-shaped ball races 86 which cooperate with registering. grooves 61 'in the supporting sleeve 41 to receive anti-friction balls 68 and thereby establish a sliding connection. The

mounting sleeve 41 is provided with an individ- To insure against escape of the anti-friction balls 68, ball retaining rings H and 12 are secured to the ends of the mounting sleeve 41 in any suitable manner as by screws Na and 52a. The rings H and 12 are provided with internal gaskets 13 which engage the outer cylindrical surface of the tube 48. The portions of the mounting sleeve 41 provided with the grooves 6! are somewhat enlarged radially to accommodate the said grooves, and the rings H and H are correspondingly shaped.

The ring. H and mounting sleeve 4l are'provided with registering

slots

14 and 15, respectively. in which the offset arm 16 of a bracket Tl is slidable. The arm i5 is secured as by one or more screws 18 to the tube 48 and moves therewith, and serves as an additional means whereby the tube 48 and the parts secured there to are splined throughout part of the movement with respect to the mounting sleeve 471.

a The mounting sleeve 4'! is provided at a point remote from the bracket l! with a depending lug l9, and the lug l9 and bracket T! are yieldably urgedaway from each other by a spring 80 disposed therebetween and surrounding telescopic elements 8| and 82, removably secured to the parts TI and l9.

The lug 79 has also removably secured thereto a rod 83 extending toward the bracket 11, and the bracket TI has removably secured thereto a guide member 84 which extends toward the lug 7 l9 and is provided with a hole 85 through which the rod 83 extends. Stop means such as lock nuts 88 are applied at a desired location along the rod 83 for engagement with the portion 81 of the guide member 84 which is telescoped about the rod 83, to limit the movement of the bracket 11 away from the lug '59 under the influence of the spring 80.

The'bracket TI is provided adjacent its lower end with a slot 88 through which the threaded shank 89 of a clevis 90 is adjustably received. The shank 89 is flattened on opposite sides as shown at 9! to fit in the slot 88 so that the shank 89 is slidable but not rotatable therein. Adjusting nuts 92 applied to the shank 89 on opposite sides of the bracket 11 serve to adjust the clevis 90 both vertically and horizontally respecting the bracket 11.

The clevis 90 carries a roller93 which operates as a follower in conjunction with a cam to be hereinafter fully described.

Referring now more particularly to Figures 1 and 5,

brackets

94 and 95 for a cam indicated gen- 15 erally at 96 and consisting for illustrative purposes only of two parts 91 having edges 98 are secured to the conveyor 2 between the supporting elements SI for the bar A to be polished or ground. The cam 96 is formed preferably from another bumper bar and consists of that portion of the bumper bar which includes the offset edges, and is retained in the flattened or uni-planar condition as shown in Figure 1. Where the length of the cam will permit, it may be made in one piece; otherwise, it is made in two or more pieces as shown in order that the conveyor 2 may traverse the pulleys upon which it is mounted, without difficulty. The width of the cam 96 is immaterial, but it is necessary that at least one of its edges, preferably the edge 98 adjacent the roller or follower 93, conform exactly to the corresponding edge of the bar A to be ground, and this will of course be the case since the cam is made from a bar which is identical with the bar A. The parts 9'! of the cam are sufficiently close together as shown at 99 to establish substantial continuity of the edge 98.

Preferably two

brackets

94 and 95 are employed for supporting each cam part 91, although 40 it will be understood that one or any other number of supports for each part 91 may be provided so long as the same is properly positioned to perform the intended function. Plates I89 are disposed between the belt 2 and

brackets

94 and 95, 45 and are secured to the belt 2 as at IUI. The

brackets

94 and 95 are mounted on the plates I00 by pin and slot connections I82 so that the same may be adjusted to thereby adjust the cam 98 laterally.

It will be observed that the follower 93 is arranged so that when the guide member arm 81 abuts the stop means 86, the follower contacts the edge 98 where the latter is not offset as at I03. Assuming that the belt 2 moves as indicated by 55 the arrows B, the bar A will be engaged by the grinding wheel 8 substantially at D since the adjustable stop [9 is arranged to prevent the wheel 8 occupying a lower position. The follower 93 at that time will be positioned at a point spaced from 60 the forward end I04 of the cam 98, the wheel 8 being positioned in proper grinding relation to the bar A by the spring 80 and the engagement of the

stop instrumentalities

86 and 87. The wheel 8 is maintained in the same plane by the same instrumentalities throughout that portion of the bar A which is straight, i. -e., until the point E in the bar A is reached where the edge of the bar begins to deviate or bend. At this point, the follower 93 of that particular wheel is positioned as shown at the left in Figure 1, in substantial engagement with the extreme forward portion I93 of the cam edge 99. During the movement of the wheel 8 from the position D to 75 the position E, the wheel is raised by a cam action afforded by the fact that the bar A between these two points is bowed.

As the bar A continues forward, the follower 93 is shifted laterally by the offset cam edge 98 causing the wheel 8 to shift exactly in accordance with the shape of the bar A from the point E to the point F which for illustrative purposes is shown as located, at the center of the bar A and at which point the maximum amount of shift of the wheel 8 has been effected by the cam 96. It will be observed that the roller 93 is of such length and is so adjusted in the slot 88 of the bracket 11 as to compensate for the bow in the bar A throughout the portion of the bar which is offset, namely from the point E to substantially the point F in the upward movement of the wheel 8, and from F to G corresponding to the point E but on the down side of the bar A. This accounts for the showing in Figure 1, wherein the roller 93 at the left is shown engaging the cam 95 at approximately half the height of the roller, and the roller in the middle of the figure engaging the cam 96 adjacent the lower end of the roller. Obviously the stop means 86 may be positioned elsewhere along the rod 83 according to the extent to which the edges of the bar to be ground are offset, and the clevis 98 may be adjusted vertically of the bracket H, and the size of the clevis and roller carried thereby correspondingly varied for bumpers which are more or less bowed.

By reason of the fact that the grinding wheel head is floatingly supported, the grinding wheel, which conforms transversely to the transverse contour of the surface to be ground (in this instance the surface to be ground is convex) is enabled to be shifted by the bumper bar itself in accordance with the slight unevenness of its edges resulting from the various treatments to which the bar is subjected in the formation of the same as a bumper bar Thus the entire surface of the bar to be ground will be polished with an even smooth finish, without high spots or dull spots.

To the end that any bumper bar having a surface to be ground which is other than straight, transversely, such as a transversely convex bar herein illustrated, but whose edges are not offset, may be given a uniform finish, the telescoping parts BI and 82, the cooperating spring 80, the clevis 90, roller 93, cam 96, and associated instrumentalities may be dispensed with. As explained in a previous paragraph, the shape of the bar and grinding wheel, transversely, is such as to cause the wheel to follow all inaccuracies in the edges of the bar, thereby aifording a smooth finish for the surface to be ground. In such event, the stop instrumentalities comprising the guide element 84 and'rod 83 are retained and a second stop means 86a employed in conjunction with the stop means 86. The two stop means 86 and 88a are preferably spaced apart sufficiently to allow the guide arm 8! to have a travel therebetween to an extent somewhat in excess of the width of the bar to be ground, so that the grinding wheel 8 may travel suificiently laterally of the bar in accordance with the irregularity in the edges thereof. Such irregularities as may exist in the edges of the bar will be slight and the grinding Wheel will float between the two stop means 86 and 86a, so that the wheel will readily pass into proper position onto the following bar without the need of any special positioning means. It will thus be apparent that by establishing what amounts substantially to a tongue and groove relationship between the bumper bar and. the polishing "wheel, 'as by employing a grooved wheel when grinding a flat or crowned bar, or "a transversely convex'surfaced wheel for a transversely concave bar, a uniformly polished surface on the bar'will be obtained in spite of edge irregularities therein. In addition this relationship makes itpossible for the wheel, by reason of its ility tomove freely in an axial direction, to shif n" accordance with the offset in the bar, the bar itself in such cases serving as the means for shifting the wheel and holding the same in proper position for polishing. With the bar having one or more edge offset portions and this relationship established, the stop means 86a may be removed and a spring means such as that described above employed for urging the grinding wheel head outwardly. Such a spring need only be of sufficient strength to overcome whatever resistance is offered by the ball spline connection and would not be suflicient to cause the wheel to grind one portion of a transversely non-recti== linear bar more than another portion thereof. The spring would, however, position the grinding wheel so that upon leaving one bar it Would be correctly positioned to readily engage the proper portion of the surface of the succeeding bar to be ground.

It will be seen from the foregoing that in accordance with the present invention there is provided means for grinding a longitudinally fiat or bowed bar in such a manner that the surface operated upon will have a uniform finish, regardless of edge irregularities or offsets in the bar and regardless whether the surface to be ground is transversely rectilinear or non-rectilinear.

t will be noted that clamp flanges I are applied on the shaft 9 on opposite sides of the grinding wheel 8 for holding the same in proper operative position. If desired, shims or washers may be employed in conjunction with these flanges for the purpose of adjusting the wheel 8 along the shaft 9.

I am aware that many changes may be made and numerous details of construction may be varied through a wide range without departing from the principles of this invention, and I, therefore do not purpose limiting the patent granted hereon otherwise than necessitated by the prior art.

I claim as my invention:

1. In a machine for polishing a longitudinal substantially sinuous surface of a bumper bar, a support for holding such a bar in a position to be engaged by a polishing wheel, a polishing wheel having a polishing surface of a width sub stantially equal to the maximum dimension of the bar surface at right angles to the plane of rotation of the wheel, means for driving the wheel rotatably, means for causing relative movement between the support and the wheel in a direction parallel to the plane of the wheel, means for causing the wheel to automatically shift axially relative to the bar as the wheel passes along the diagonal part of the bar tothereby polish the sinuous surface of the bar, and means providing a support for the wheel so that the same may float up and down in a plane of its axis, to enable the wheel to polish vertically offset portions of the surface of the bar.

2. In a machine for polishing edge-offset bars, a movable support for such a bar, a template movable with the support and having an edge parallel to an offset edge of the bar, a plurality of polishing wheels, means supporting the wheels for axial movem'ent and a follower for said template and" movable with each of said wheels; wherebys'aid wheels will simultaneously polish relatively offset portions as well as relatively alined portions of the bar during continued movement of the latter. r I 3.' In a machine for polishing edge-offset bars, a movable support 'for such a bar, a template movable with the supportand having an edge parallel to an offset edge of the bar, .a plurality of polishing wheels, means supporting the wheels for axial movement, and a follower for said template and movable with each of said wheels, whereby said wheels will simultaneously polish relatively offset portions as well as relatively alined portions of the bar during continued movement of the latter, and means for yieldably holding the followers in engagement with the template.

4. In a machine for polishing edge-offset bars, a movable support for such a bar, a template movable with the support and having an edge parallel to an offset edge of the bar, a plurality of polishing wheels, means supporting the wheels for axial movement, and a follower for said template and movable with each of said wheels, whereby said wheels will simultaneously polish relatively offset portions as well as relatively alined portions of the bar during continued movement of the latter, and means for limiting axial movement of the wheels so that the followers are in position to engage the suceeding templates for enabling the wheels to polish succeeding bars.

5. A polishing machine including a rotary polishing member for polishing a bar, said bar having portions relatively offset transversely with respect to a plane of rotation of said member, and means for conveying the bar relative to said member in the general direction of the length of the bar, said member being supported for movement transverse to said plane and being formed to have a cam and follower relation with the bar so that said member will be shifted transversely of said plane by the bar as the bar is conveyed, and means for holding the polishing surface and the surface to be polished interengaged under pressure during the polishing operation.

6. A polishing machine including a polishing member for polishing a plurality of bars each having a portion relatively offset transversely with respect to a plane of rotation of said member, and means for conveying said bars relative to said member in the general direction of the length of the bars, said polishing member being supported for movement transverse to said plane and being formed to have a cam and follower relation with each bar so that said member will be shifted transversely byeach bar as the bar is conveyed, means for holding the polishing surface and the surface to be polished interengaged under pressure during the polishing operation, and means for supporting the bars in a longitudinal series with the rear end of each aligned in tandem with the front end of the succeeding bar, whereby upon becoming separated from the rear end of one polished surface said member becomes engaged with the front end of the succeeding surface to be polished, without adjustment.

'7. In a machine for polishing bars such as bumper bars, a plurality of rotary polishing wheels, means for supporting the bars longitudh nally substantially parallel to the wheels, means for moving the support in a direction parallel to said wheels, means mounting each of the wheels for independent and combined axial and cross-axial movement in addition to its rotation, so that the same polishing area thereof may polish selectively a straight bar, a bar having an edge offset in a plane parallel to the Wheel axis, a bar whose edges are offset in a plane at right angles to the wheel axis, and a bar having portions of its edges ofiset in neither of said planes, said wheels being spaced longitudinally to such an extent as to be engageable with spaced portions of the same bar, and means for holding the wheels in polishing engagement with such spaced portions of a bar, regardless whether such portions are relatively offset.

OWEN DOU'I'I.