US3258804A

US3258804A - Centerless finishing machine

Info

Publication number: US3258804A
Application number: US460221A
Authority: US
Inventors: John M Fowle
Original assignee: DURA BOND BEARING CO
Current assignee: DURA BOND BEARING CO
Priority date: 1965-06-01
Filing date: 1965-06-01
Publication date: 1966-07-05
Anticipated expiration: 1983-07-05

Description

July 5, 1966 J. M. FOWLE 3,258,804

CENTERLESS FINISHING MACHINE Filed June 1, 1965 INVENTOR. JOHN M. FOWLE Q 3,, b m-2A A 7' TO/QNE V United States Patent 3,258,804 CENTERLESS FINISHING MACHINE John M. Fowle, Los Altos Hills, Calif, assignor to Dura- Bond Bearing Company, Palo Alto, Calif., 21 corporation of California Filed June 1, 1965, Ser. No. 460,221 4 Claims. (Cl. -88) This invention rel-ates generally to the centerless finishing art wherein a work piece having a generally cylindrical form is finished while the work piece is supported at its periphery and not on centers. More specifically the invention is directed to the problem of removing b-urrs and sharp edges from machined parts. An example of such a part is a bearing sleeve having surface holes, slots or other machined cavities.

The main object of the present invention is the provision of a centerless finishing machine which is particularly adapted to remove burrs and sharp edges from cylindrical work pieces in one pass through the machine. In this connection there are presently avail-able centerless deburring machines employing wire brushes in which the conventional centerless grinding principle is employed except that a rotating brush is substituted for the large rotating grinding wheel employed in the typical centerless grinding operation. An important disadvantage of conventional centerless deburring devices is that two passes are required through the machine to satisfactorily complete the deburrin-g operation, or two machines are required through which the work piece is passed successively. The reason for the two separate operations is that the rotating wire brush is effective to clean only that edge of a hole or cavity which the wires of the brush strike last. In other words, the edge of a hole or cavity closest to the approaching wires of the brush do not receive the same impact as the edges last engaged by the wires of the brush. The reason for this is that the wires of the brush enter the hole or cavity and are impacted against the edges they engage as they leave the cavity. For example a bearing sleeve having a drilled hole will not be satisfactorily deburred along the edge of the hole which the wires of the brush engage first but will be satisfactorily deburred along the edge which they engage last. This effect is seen in FIG. 4 of the drawings. In view of this particular effect it has been customary in the past to pass the work piece through a center-less deburring machine with one end of the piece leading and then pass it through again with the opposite end leading. This procedure results in reversal of the edges that are exposed to the greatest abrasive action of the wire of the brushes thereby achieving satisfactory deburring and finishing effect.

By the present invention it is only necessary to pass the work piece through the machine once to achieve the desirable effect of having the wires of the brush imp-act the entire circumferential extent of the outer edge of the hole, slot or cavity formed in the periphery of the work piece.

Other objects and advantages of the invention will be apparent from the following specification and from the drawings.

FIG. 1 is a top plan view of the essential portions of the centerless finishing machine. Safety guards and other elements normally associated with this type of equipment are omitted from the drawings for clarity.

FIG. 2 is a front elevation of the machine of FIG. 1 as taken in a plane indicated by lines 2-2 of FIG. 1.

FIG. 3 is an enlarged cross section taken in a plane indicated by lines 3-3 of FIG. 1.

FIG. 4 is a schematic fragmentary view showing the cooperation between brush and the work piece.

The invention makes use of the well known centerless machining principle and includes a regulating wheel of abrasive material designated I. Said wheel is shown on the drawings as supported by a bearing 2 at one end and driven at its opposite end from a motor 3. As is well known the axis of regulating wheel 1 is inclined slightly to the path of travel of the work pieces so that the periphery of said wheel supports the work pieces and at the same time feeds the same in a direction generally axially of the wheel.

In this description the work pieces illustrated are sleeve bearings 7 which are fed to the machine along an inclined chute 8 and which then pass along the regulating wheel 1 supported on a lower work rest blade 9 (FIG. 3). Said work rest blade 9 extends the length of regulating wheel 1 and is supported at one end on a blade support structure 10 and at its opposite end in a similar blade support structure 11. This structure is conventional and no claim is made thereto except in combination with the present invention. By the present invention it is necessary to provide an upper work res-t blade 12 which is also mounted in the blade support structure as best seen in FIG. 3. It will be noted that the

work rest blades

9 and 12 are spaced apart a distance slightly greater than the extent of the work piece 7 at said blades so that said pieces may engage the blades successively.

The work pieces 7 from supply chute 8 are first engaged by a wire brush 15 which is indicated in FIG. 1 as rotating in a direction to urge the work pieces into engagement with the lower work rest blade 9. It will be understood that the regulating wheel 1 rotates at a relatively low rate of speed while the wire brush 15 rotates at a relatively high rate of speed.

Wire brush 15 is fixed to one end of a shaft 16 which is supported in a bearing 17 and which is provided at its opposite end with a pulley 18 driven through a belt 19 from a motor 20.

Alongside brush 15 and substantially coaxial therewith is a second wire brush 21 fixed to one end of a shaft 22 supported in a bearing 23. A similar drive including motor 24 and belt 25 is employed to rotate brush 21 in a direction opposite to the direction of brush 15.

After the work pieces 7 leave the region of the first brush 15, they continue through the machine until they are subjected to the thrust of the second brush 21. The thrust of this brush is, of course, in the opposite direction or upward. This lifts the work piece 7 upward into engagement with the upper work rest blade 12. The face angle of the upper blade is disposed opposite to the lower blade so that the opposite angle combined with the opposite direction of force result in a continuation of the positive driving action of the regulating wheel 1.

After the work pieces 7 have been discharged from the

work rest blades

9 and 12 they are conveyed away on a discharge chute generally designated 27.

By the above described structure it will be apparent that any apertures formed in the work pieces 7 will be smoothed and deburred completely in one pass through the machine since the upper and lower edges of such apertures or cavities will both be exposed to the impact action of the wires of the brushes. As best seen in FIG. 4 the brush 15 has the effect of smoothing out the lower edge 31 of aperture 29 in work piece 7 while leaving the upper edge 30 sharp. However the subsequent engagement of work piece 7 with the oppositely rotating brush 21 completes the deburring operation by smoothing out upper edge 30. The side edges of such holes or apertures will, of course, also be subject to the smoothing action of the wires of the brushes.

It will be apparent from FIG. 3 that the

work rest blades

9 and 12 should be spaced apart a distance such that only a slight amount of clearance exists between one blade and the work piece when the work piece is being urged against the opposite blade by whatever one of the two brushes it engages.

In many centerless operations the work pieces are disposed in an above center position which often has certain advantages in operations of great accuracy. In a wire brush deburring operation of the type for which the present invention is particularly suited above center operation holds no advantage over on center operation. In the above described structure it has been assumed that the work pieces are substantially on center with respect to the common axis of

brushes

15, 21.

It Will be understood by analogy to conventional centerless grinding operations that the speed of rotation of the regulating wheel 1 is relatively low and may impart a peripheral speed to the work pieces between 50 and 250 feet per minute. The peripheral speed of the brushes should be in the order of from 4000 to 7000 feet per minute. Insofar as the relative speed between a brush and the Work is concerned it will be noted that in one case the speeds are additive while in the other the effective speed is the diiference between the two surface speeds. In a deburring operation it will be appreciated that these dilferences in working speeds between the two stages is inconsequential and do not have any practical effect on the deburring operation.

As noted above, the usual auxiliary components associated with this type of equipment have been omitted from the description including the usual dressing wheel for maintaining the regulating wheel in good condition. Also the means for feeding the regulating wheel 1 toward the work has been omitted for clarity.

It should also be noted that the present invention contemplates polishing and grinding operations as well as deburring operations in order to obtain whatever advantages accrue from the dual finishing operations to which the invention lends itself.

The above veryspecific description of the preferred form of the invention should not be taken as restrictive as it will be apparent that various modifications in design may be resorted to without departing from the scope of the following claims.

I claim:

1. Centerless finishing apparatus comprising:

means providing centerless support for a work piece,

a regulating wheel including drive means for feeding said piece along a path of travel in one direction,

a first finishing member on the opposite side of said path from said regulating wheel and adapted to engage said piece,

means driving said member in one direction,

a second finishing member alongside said first member and in engagement with said piece,

means driving said second finishing member in a direction opposite to said first member.

2. A device according to claim 1 wherein'said centerless support includes a pair of vertically spaced work rest blades for supporting said piece against substantial vertical movement.

3. A device according to claim 1 wherein said finishing members are wire brushes.

4. Apparatus for deburring generally cylindrical work pieces comprising:

means providing centerless support for a Work piece,

a rotating regulating wheel for feeding said piece along a path of travel in one direction,

a first brush on the opposite side of said path from said regulating wheel and in deburring engagement with said work piece,

means driving said brush in one direction,

a second brush substantially coaxial with said first brush and in deburring engagement with said Work piece,

means driving said second brush in a direction opposite to said first brush.

References Cited by the Examiner UNITED STATES PATENTS 1,692,985 11/1928 Gallison 1588 X 2,238,720 4/1941 Duaei et al 1588 3,218,658 11/1965 Collins et al. 15-88 CHARLES A. WILLMUTH, Primary Examiner.

Claims

1. CENTERLESS FINISHING APPARATUS COMPRISING: MEANS PROVIDING CENTERLESS SUPPORT FOR A WORK PIECE, A REGULATING WHEEL INCLUDING DRIVE MEANS FOR FEEDING AND PIECE ALONG A PATH OF TRAVEL IN ONE DIRECTION, A FIRSAT FINISHING MEMBER ON THE OPPOSITE SIDE OF SAID PATH FROM SAID REGULATING WHEEL AND ADAPTED TO ENGAGE SAID PIECE, MEANS DRIVING SAID MEMBER IN ONE DIRECTION, A SECOND FINISHING MEMBER ALONGSIDE SAID FIRST MEMBER AND IN ENGAGMENT WITH SAID PIECE, MEANS DRIVING SAID SECOND FINISHING MEMBER IN A DIRECTION OPPOSITE TO SAID FIRST MEMBER.