US2581270A - Variable abrasive belt backup wheel - Google Patents

Description

Jan. 1, 1952 McVEY VARIABLE ABRASIVE BELT BACKUP WHEEL Filed Nov. 29, 1949 V m y g a m. T 4 YA L Y 2 w Patented Jan. 1, 1952 UNITED STATES PATENT OFFICE Y 2,581,270

VARIABLE'ABRASIVE BELT BACKUP-WHEEL I Elden N. McVey, Ashtabula Ohio, Application November 29, 1949,1Serial No; 129,959 6 Claims. (Cl..51?14 Thisinvention relatestogrinding and polishing apparatus, and'more particularly to an improved form of back-up wheel for holding. an abrasive belt or the like incontactwith the material be:- ing-ground or polished;

. Inthegrinding or polishing-ofimaterial such as metal sheets, strips, knives tools; lids and other such articles that have either a flat surfacetor gently curving surface, it is customary practice to employ a presseror back-mp wheel to =hold'or back-up an abrasive-belt against the surface of such material. Itisimportant that a=back-up wheel develop'suflicient pressure against theb'elt to-insure maximum belt life and maximumcutting action by the individual grains of abrasive. Inaddition, it must be sufficiently flexible to conform with the contour of the material being ground or polished. I

' It'has been found that-a-Wheel having asolid face which isfiexibleenough to shape itself to the contour of the material being-ground cannot produce sufiicient pressure to effect the maximum rate of cut. Thedesired pressures-can only be developed by wheels having an intermittent face. Such a wheel allows the piece being ground or polished intermittently to depress below the surface of' the-wheel, the projecting surface then contacting the work-piece, thereby eif'ectingan intermittent striking, or saw-tooth,- action-and producinggreatpressurer Furthermore, maximum belt life can only be attained by the application of sufficient pressure to cause individual grains of abrasive topenetrate the --material being ground to adepth wherethe grainspull out of the bond holding them to the belt when-they become dull or worn. Asa result of -"sueh increased pressure as is caused by a wheel having an intermittent face, the belt-continuously presents'anew cutting surface as grains of abrasive are shed, thus insuring-maximum cutting action.

It is a primary object of this invention to provide aback-upwheel having all theabove-enumerateddesirable characteristics.

Otherpbiects and advantageswill becomeapparent as thexfollowing description proceeds.

Totheaccomplishment of the foregoing and pulleys.

In said-annexeddrawing:

Fig. 1 is a, longitudinal sectionalview ofjagrinding or polishing. machine Fig; 2 is aside elevation ofa back-upzwheel within the principle of myinventioni.

Fig. azis a front view-.of'the backsup-rwheel shown in Fig. 2', partly in section;

Fig. 4. is .a front view of a portion ofaback-up wheel having amodi-fied form of construction;

Fig.- 5- is:a:longitudinal sectional viewof :a specialcontourback-up bar; and

Fig: d is a transverse seetional'view of a:back.- upbar;

Referring: now to thedrawing and :more --espe ciallyto Fig. 1 thereof, the grindingaor polishing machine there indicated is supported by side frames only one of whichbeing. thereshown. Pairs-of guiding orfeed rollers 2 and-3 are journaled in the side frames- 1, either or. both of which-may be-drivenfrom asuitable source of power-to advance a-inetal sheet or strip 4- through the mach-inst Pulleys- 5 and -6: are journaledin the side frames I of the upper portion of-themachine; an abrasive belt I passing-aroundsuch Abrasive be1t'8 passes around pulleys-'9 and ljou-rnaled in theside frames! in thelower por-tion of the machine. A motor" l is-provided to drive the pulleys to effect movement of the belts '1 and-8t Back-upwheels I 2 are-journaled intheside-frames I of the machine-andserveto hold-"respective belts l and Sin grinding engagement with the'workl. g

Referring next to Fig. 2, the back-up-wheel l2 comprisesa shaft l3, a -bus'hi-ng I4, anda hub-lfi, the latter having a flange I centrally about its periphery. A pair of identical circular discsor side plates- 11- are secured-to the flange I'B- by means of bolts t8, the side plates being-formed with aseries of-circumferentially spaced slots I9 adjacent-their peripheriesi A- series ofopenings or-vents 20' are formed in each side plate-l1 disposed in circulararrangement about theaxis thereof? A plurality of axially disposedback-up bars areprovided about the peripheryof the wheel; such bars comprising inserts '2 I preferably of a hard metallic substance, secured between the sidepla tes llby extending into respective slots their-respective slots:

The inserts 2! are provided witha resilient covering- 23; preferably of rubber or'-a-plastic material; which covering extends-beyond the periphery'ofthe sideplates, the cuttingarea- 24 of the covering 23 being adapted to bear upon the belt at the point of contact of the latter with the surface being ground or polished. A special contour bar as, for example, the one shown in Fig. of the drawing, may be provided for workpieces having a surface of a particular contour.

Thus, the entire assembly is made so that by removal of the bolts 18 securing the side plates I! to the flange it of the hub, all of the parts may be quickly disassembled permitting the use of different side plates and back-up bars to vary the diameter and width of the wheel. Likewise, change may be made in the peripheral surface of the back-up wheel by changing the spacing between the back-up bars (as, for example, by removing alternate bars from the wheel) It will be noted that increasing the spacing between the back-up bars produces a more definite striking, or saw-tooth, action as the latter intermittently press the belt against the surface being ground or polished, thus increasing the pressure whereby greater cutting action is obtained. Of course, if more flexible back-up bars are substituted, it is necessary to provide even greater spacing to obtain the same amount of pressure.

The backup bars may be replaced by others having difierent cutting areas and having covers of varying degrees of resilience. Referring to Fig. 6 of the drawing, it is seen that the metallic bar or insert 21 is rectangular in cross-section and thus may be rotated 180 to present a greater cutting area and thus increase the rate of out. It is, of course, obvious that inserts having other cross-sections may be employed whereby such inserts may be rotated and secured in any number ofselected rotative positions so that the cutting area which bears upon the abrasive belt may be varied as desired, limited only by the number of rotative positions available.

The back-up wheel of my invention is thus seen to be quickly adaptable to varying peripheral surface requirements and to work-pieces of a variety.

of conformations.

Fig. 4 shows a back-up wheel having a modified form of construction. Instead of being axially disposed about the wheel, the back-up bars 25 are there illustrated as being helically disposed thereabout. It is well known to those familiar in the art that at certain critical speeds of belt travel, chattering of the belt often occurs. The modified form of construction of back-up wheel shown in Fig. 4 of the drawing serves a purpose in addition to those described with reference to the previous embodiment in that such wheel serves also to prevent chattering of the belt, since the latter will be held against the work at all points along the length of contact without any intermediate portions of belt being unsupported.

The same result may be obtained with the embodiment previously described by securing the back-up bars in non-opposed slots of the side plates to effect helical placement of the bars, or, for finer adjustment, by forming the side plates so as to be relatively rotatably adjustable, whereby the back-up bars may be disposed axially or helically as desired. Of course, by reducing the spacing between the back-up bars, the intermediate portions of unsupported belt may be correspondingly reduced, thereby lessening the tendency of the belt to chatter.

It should be noted, however, that the intermittent striking action or saw-tooth effect caused by circumferential spacing of the back-up bars is most effective where such bars are disposed axially about the wheel. Thus, the degree of helical placement of the bars to reduce possible chattering of the belt must necessarily correspondingly reduce the cutting action of the belt. Rela tively close spacing of the bars also sacrifices belt cutting action, since the striking action of the individual bars is less effective to produce the high pressures necessary for a high rate of cut.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims, or the equivalent of such, be employed.

I therefore particularly point out and distinctly claim as my invention:

1. A back-up wheel for an abrasive belt and the like comprising a pair of axially spaced, substantially radially rigid circular side plates, a plurality of substantially rigid back-up bars extending between said side plates adjacent their peripheries and removably supported on said plates in circumferentially spaced relationpand a resilient covering surrounding each said backup bar and projecting radially outwardly of the peripheries of said side plates.

2. A back-up wheel for an abrasive belt and the like comprising a hub, a pair of axially spaced, substantially radially rigid circular side plates secured on said hub, said side plates being formed with a series of circumferentially spaced slots adjacent their peripheries, a plurality of substantially rigid back-up bars extending between said side plates and removably engaging such slots, and a resilient covering surrounding each said back-up bar and projecting radially outwardly of the peripheries of said side plates.

3. A back-up wheel for an abrasive belt and the like comprising a pair of axially spaced, substantially radially rigid circular side plates, a plurality of substantially rigid back-up bars extending between said side plates adjacent their peripheries, -means removably supporting said back-up bars on said plates in circumferentially spaced relation, whereby said bars may be rotated to present a different face or selectively removed to vary the spacing therebetween, said bars extending parallel with the axis of said wheel, and a resilient covering surrounding each said back-up bar and projecting radially outwardly of the peripheries of said side plates.

4. A back-up wheel for an abrasive belt and the like comprising a hub, a pair of axially spaced, substantially radially rigid circular side plates removably secured on said hub, said side plates being formed with a series of circumferentially spaced slots adjacent their peripheries, a plurality of substantially rigid back-up bars extending parallel with the axis of said wheel removably secured between said side plates and engaging such slots, and; a resilient covering surrounding each said back-up bar and projecting radially outwardly of the peripheries of said side plates.

5. A back-up Wheel for an abrasive belt and the like comprisin a hub, a pair of axially spaced, substantially radially rigid circular side plates removably secured on said hub, said side plates being formed with a series of circumferentially spaced slots adjacent their peripheries, a plurality of substantially rigid helically disposed, mutually parallel back-up bars removably secured between said side plates and engaging such slots, and a resilient covering surrounding eachsaid back-upbar and projecting radiallyoutwardly from the peripheries of said side plates.

6. A back-up wheel for anabrasive belt and the like comprising a pair of axially spaced, substantially radially rigid circular side plates, a plurality of substantially rigid back-up bars displates adjacent their ELDEN N. McVEY.

6 REFERENCES orrEn Number UNITED STATES PATENTS Name Date Cummins June 30, 1891 Courtney Dec. 12, 1911 Dade Sept. 27, 1927 Howland July 24, 1928 Schulte Jan. 28, 1930 Mason Jan. 17, 1933 Schneider July 28, 1936 Herchehrider June 13, 1939 Losey June 19, 1945 Hill Nov. 26, 1946 Herchenrider Aug. 2, 1949 Kirstek -1. Jan. 17, 1950

Images