US 2977725 A
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Description (OCR text may contain errors)
April 1961 J. A. SIMENDINGER 2,977,725
CONTACT WHEELS Filed May 13, 1957 INVENTOR. M h A, simenallrger ATTORNEYS finishing operations.
hard root portion.
' 2,977,725 CONTACT WHEELS Joseph A. Slmendinger, 171s Huntington Stratford, Conn.
This invention relates to contact or drive wheels especially adapted for backing-up an abrasive belt for abrasive In the past, drums having rubber tire-like faces thereon have been employed as back-up wheels for driving orv supporting abrasive belts or the like. Due to use of different belts and the differences in theobjects being operated upon, it is desirable to be able. to-select a wheel surface having the proper duronieter or resiliency for the operation to be performed. This is normally done by the use of a plurality of complete wheels, since the surfaces thereon have not been readily changeable.
' In order to overcome the deficiencies present in the previously used back-up wheels, a metal or solid material drum having its periphery slotted or serrated and having resilient inserts held in the slots, as disclosed in applioants copending application, Serial No. 515,815, filed June 16, 1955, now US. Patent No. 2,850,853,'granted' September 9,1958, has been used. This type of back-up ever, it has been found advantageous to have the root.
portion of the insert which fits in the root portion of the drum of a higher durometer, i.e., a harder material, than the face portion of the insert, which contacts the belt.
' One of the objects of the invention is to provide a contact, back-up, or drive wheelfor abrasive belt finishing arranged so that the desired surface resiliency can be readily obtained, while maintaining a constant relatively Another of the objects of the invention is to provide inserts fora contact or drive wheel having different hardness characteristics at various portions thereof.
Still another object of this invention is to provide inserts of a relatively soft, or low durometer, material in which the root portion and the connecting portion are compressed so as to increase their hardness.
In one aspect of the invention the contact or back-up wheel may comprise a metal or solid material rotatable drum having a plurality of axially extending slots in its periphery, each of the slots having a widened root portion within the drum. In a preferred form, the widened root portion of the slot has a generally circular configuration and connects with the narrow slot cut in the drum periphery. Resilient insert members having widened root portions for filling the root portions in the drum and widened face portions wider than the slots and overlying, in part, the surface of the drum, are arranged to he slid into the slots from the side of the drum. The root portions of the inserts preferably are harder than the face portions thereof. The softer face portions of the inserts, when in position in the slots on the drum, contact the abrasivev belt which extends partly around said drum.
In one aspect of the invention, the resilient inserts are formed from a generally rectangular body of sponge rubber or the like, the lower portion of which is com Patented Apr. 4, 1961 ice ' i the invention will become apparent from the following insert;
of the present invention;
I In the drawings;
. QFigQ'l is a schematicview of one manner in which the invention can be used; 7
Fig. 2 is-an enlarged side view of the back-up wheel "1 Fig. 3 is an enlarged fragmentary view, showing one manner in which the invention operates;
Fig. 4 is an enlarged fragmentary view of one. form of Fig. 5 is an enlarged fragmentary view of another form of insert.
The wheel 'of this invention maybe used for various purposes but will be described specifically as a back-up arrangement for an endless abrasive belt finishing or abrading machine. Frame (Fig. 1) may carry wheel 11 and wheel 12, wheel 11 being driven by a suitable motor- (not shown). Endless abrasive belt 13 extends between .the wheels, the belt being driven at a relatively high linear speed. Work table 14 provides a support for work piece 15 which can be placed thereon, the work piece being pressed into contact with abrasive belt 13 so as to finish the face thereof.
In a preferred form, the back-up wheel may include a drum 16 (Figs. 2 and 3) having a hub 17 with anaperture 18 for mounting on a suitable shaft. Annular flange or rim 19 of drum 16 is carried by web 20, annular flange 19 having a plurality of slots 21 extending across periphery 22 of flange 19 or in an axial direction of the drum. The slots have a widened root portion 23,
such being generally circular in the preferred form. It is to be understood thatthe widened root portion may take other equivalent forms to accomplish the desired purpose.
Inserts 24 made, for example, from extruded rubber, neoprene, sponge material, or other similar rubber-like resilient material, have a root portion 25 connected to a face portion 26 by a narrower connecting portion 27, said portions extending axially of the drum when in place thereon. The underside of-margins 28 of face portion 26 is generally related to root portion 25 and the slot dimension so that margins 28 will closely grip the adjoining surfaces of periphery 22 when the inserts are in position on the drum.
As can be seen in Fig. 3, belt 13 may be irregularly displaced by work piece 15 as work piece.15 is pressed inwardly against the abrasive belt. The inserts directly thereunder will yield to permit the belt to tend to follow irregularities in the face of the work piece if the face portions of the inserts have the proper resiliency. After the belt passes the work piece, the inserts will again resume their original form and tend to flex the belt outwardly so as to eject particles from between the abrasive grains.
The inserts of the invention are formed so that the face portion 26 may be of any desired resiliency or durometer, while the root portion 25 and the connecting portion 27 are formed so as to have a high durometer or high hardness so that they will not diminish in size and pass through the slots in the surface of the drum, due to the centrifugal force created by the peripheral speed of the drum. This may be accomplished by molding the insert from two separate strips of uncured rubber or the like having different hardness characteristics. As the strips are molded under heat and pressure they will join together in a perfect bond to form the interconnecting portion, between the face portion composed of the soft strip and the root portion composed of the hard mixture, thereby forming a unitary insert having portions thereof with different hardness characteristics.
In the insert shown in Fig. 5, the hardness of the interconnectingportion and the root portion thereof is increased by compressing the lowerpart of the insert which forms these portions with a metal clip member 29. This member may be applied by a press which would bend a flat strip of metal into the desired shape. In the preferred form the insert 24a is formed from a sponge-like material having a very low durometer; It is obvious that the spring clip 29 maybe applied in many other'ways.
In'the event it becomes desirable to change the re siliency of the wheel surface, it is merely necessary to slide the inserts from their slots and replace them with inserts having the proper durometer, diameter, and face width.
The described inserts tend to stay in position when the wheel is being operated and not to slide axially. If
required, plates (not shown) could-be put on either side of the drum, although such has not been found necessary, or the wheel may be grooved in the manner described in the above mentioned copending application.
It should be apparent that details of construction can be varied and the construction used for various purposes, such as polishing, without departing from the spirit of the invention except as defined in the appended claims.
What is claimed is:
1. In a contact back-up wheel, a rotatable drum having a plurality of transversely extending slots in its periphery, each of said slots having a circular root portion in said drum and a narrow slot portion between said root portion and the periphery of the wheel, so as to define a stop surface at the radially outer portion of the root portion on either side of said narrow slot, and contact members having circular base portions for filling the bare portions in the drum contact portions wider than said slots extending beyond the surface of said drum, and portions connecting the base portions and the contact portions and filling the narrow slots, said base portions of the inserts being hard enough to resist compression sufiicient to permit them to move radially through said narrow slots under centrifugal force generated by the rotation of the drum and said contact portions being softer than said base portions both before and after said inserts are inserted insaid slots.
2. A resilient contact wheel insert comprising an elongated face portion, an elongated root portion, a portion joining said root portion to said face portion, and a resilient metal clip member longitudinally enclosing and transversely compressing the root portion and the joining portion, thereby causing said root portion and said joining portion to be harder than said face portion.
3. In a back-up wheel, the combination including a rotatable drum having a plurality of transversely cxtending slots in its periphery, each of said slots having a widened root portion in said drum, resilient contact members mounted in said slots, said members having base portions filling said slots and the root portions and widened contact portions extending transversely of said drum, said contact portions being softer than said base portions both before and after said members are inserted in said slots.
4. Ina contact back-up wheel for an abrasive belt or the like, the combination including a rotatable drum having a plurality of transversely extending slots in its periphery, each of said slots having a widened root portion within said drum, and resilient contact members mounted in said slots, said members having base portions of a relatively hard resilient material for filling said slots and said root portions and widened contact portions extending transversely of said drum, said contact portions being softer than the base portions of the inserts and being adapted to contact said abrasive belt.
References Cited in the file of this patent UNITED STATES PATENTS 2,415,308 Schulte Feb. 4, 1947 2,483,422 Larson Oct. 4, 1949 2,548,166 Larson Apr. 10, 1951 2,581,270 McKey Jan. 1, 1952 2,639,560 Cosmos May 26, 1953 2,709,879 Larson June 7, 1955 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent N0n ,2 97T 725 April 4 1961 Joseph A. Sime'ndinger It is hereby certified that error appeeirs in the above numbered patent requiring correction and that the said Letters Patent. should read as "corrected below Column 3 line 4O, for "bare" read m base same line after "'drum insert a comma.
Signed and sealed this 19th day of September 1961,
ERNEST W. SWIDER DAVID L. LADD Attesting Officer C Commissioner of Patents USCOMM-DC