US2280620A - Apparatus for finishing tubular articles - Google Patents

Description

April 21, 1942. G, w, BINNs ETAL.

APPARATUS FOR FINIHING TUBULAR ARTICLES Filed Feb. 2.8, 1939 2 Sheets-Sheet l R5. Ns d THELER ATTORNEY.

April 21, 1942. G, w. BINNS ETA;

APPARATUS FOR FINISHING TUBULAP` ARTICLES Filed Feb. 28, 1939 2 Sheets-Sheet 2 ATTORNEY.

Patented Apr. 2l, 1942 para TTES

APPARATUS FOR FINISHING TUBULAR ARTICLES of Ohio Application February 28, 1939, Serial No. 258,986

6 Claims.

This invention relates to improvements in a method of and apparatus for finishing tubular articles and relates particularly to the accurate formation or surfacing of thin-walled flexible sleeves or similar structures, being particularly adapted for use in the grinding or finishing of metallic cylinder liners for internal combustion engines.

One of the principal objects of the present invention is the provision of an improved method of supporting a flexible walled article, either interiorly or exteriorly in such manner as to maintain the same in its normal uniiexed condition by multiple application of either internal or external pressure thereto in a manner to lock the same against deformation from oppositely applied pressure incident to a machining or finishing operation.

A further object of the invention is the provision of improved apparatus for effecting multiple longitudinal and circumferential position maintenance of a flexible walled article with suitable resistance to deformation thereof during performance of a surfacing operation on the unsupported surface thereof. x

A further object of the invention is the provision of an apparatus of this character permitting ready positioning of the Work while positively maintaining the same against accidental dis placement during machining thereof.

Other objects and advantages of the present invention should be readily apparent by reference to the following specification, considered in conjunction With the accompanying drawings forming a, part thereof and it is to be understood that any modications may be made in the exact structural details there shown and described, within the scope of the appended claims, without departing from or exceeding the spirit of the invention.

Figure l is a fragmentary View of a centerless grinder in which a Work piece is being mshed in accordance with the present invention.

Figure 2 is a fragmentary plan view of the parts illustrated in Figure 1.

Figure 3 is a View partly in elevation and partly in section of a work piece suported for machining in accordance with the practice of the present invention.

Figure 4 is a view looking to the right hand end of the construction shown in Figure 3.

Figure 5 is a fragmentary longitudinal sectional View of the invention as utilized in interior support of an article to be finished.

Figure 6 is a similar view illustrating the external supporting of an article for operation on the interior thereof.

Figure 7 is a sectional view as on the line l-l of Figure 5.

Figure 8 is a fragmentary sectional View illustrating a modified form of supporting means.

fifi

Figure 9 is a sectional view as on the line 9 9 of Figure 8, and

Figure 10 is a fragmentary View illustrating the application of a terminal protective device to the work holder.

In the drawings in which similar characters of reference are employed todenote similar or corresponding parts throughout the several views, the numeral lil designates the bed of a centerless grinder having the opposed grinding Wheel Il and regulating wheel l2 intended jointly to engage a cylindrical Work piece I3 supported between the Wheels as by conventional Work rest blade lll.

An end stop l5 carried by the bed I0 serves to limit the axial movement of the work within the grinding throat.

Prior to the present invention extreme difficulty has been experienced in attempting to produce the necessary concentric truly round cylindrical surfaces on thin, flexible-walled sleeves such as are employed, for example, in lining the cylinders of internal combustion engines. This has been due to the fact that the flexibility of these Walls is such that they are bent and distorted even on the application of light pressure in the performance of surfacing or similar operations and no satisfactory method has hitherto been found by which the same, even though initially formed to substantially proper cylindrical shape, could be held in this shape without distortion for nishing of a first surface thereon.

It is, of course, understood that after either the exterior or the interior have been finished truly circular in cross section that they can then be fitted within a chuck or mounted upon an arbor for production of the second surface.

The previous difficulty has been in the producing of the first surface Without reproduction on the surface being finished of any irregularities existing on the surface employed for holding purposes, due to the distortion eiectible by such irregularities.

In accordance with the present method, hoW- ever, there has been provided a chuck or holding member which, in its dierent forms, may be applied either interiorly to or exteriorly of `the article and is provided with a multiplicity of yieldable work engaging devices individually actuated by light pressure insufficient to cause individual distortions of the article, but on the contrary, conforming respectively to the irregularities thereof.

One embodiment of the improved holding member and its manner of use is illustrated in detail in Figures 3 to 7 of the drawings. As there shown, it comprises a body portion which, for convenience of manufacture, may be formed from a series of similar bushings or collars IB, prefer n ably provided with interlocking portions such as the terminal flanges Il received in the interior recesses or sockets I 8 for building up of a sectional the springs 23 react.

tubular member designated as an entirety by the numeral I9.

Each of said sections I6 has formed therein a multiplicity of sockets 20 extending in a general axial direction with respect to the collar I6 but at a slight angle such that the outer portions break through the periphery of the collar in the elongated slots 2 I The exact angle between the axes of these sockets and the axis of the collar itself may be Varied, but preferably is such as to constitute a sticking taper with a coeicient of friction,v such as to maintain the pressure devices, such as the balls 22, against axial displacement on application of radial pressure thereto as respects the axis of the collar I6.

It is to be noted that the pressure members 22 may be inserted at the rear or inner open ends of the sockets 2U and are individually backed up by yielding pressure means which may be of hydraulic or other character but for convenience of illustration have been indicated as compression springs 23. Intertting assembly of the adjacent collars causes one collar to form a closure for the inner open ends of the sockets, each succeeding socket thus providing an abutment against which Suitable means are provided for securing the several sections together as a unit-in Figures 3 to 5, these means having been shown as a pair of discs 24 and 25 centrally connected as by bolt 26 having nut 2'I to draw the parts together with suitable and adequate retaining pressure.

In the use of this device in connection with the finishing of tubular articles, the thin-Walled sleeve or like article I3 is axially slid over the member I9. The resistance of the individual springs 23 or their equivalent is sufliciently light to permit of concomitant longitudinal and inward movement of the series of pressure members 22 in their respective sockets so that the sleeve may be readily pressed into position, being brought up, for example, against the limiting end stop 28 carried by the disc 25,

When in this position, the work piece, as indicated in Figure 3, is longitudinally and circumferentially supported at a multiplicity of points by the members 22, each individually, resiliently, outwardly urged by an equal pressure so that the internal pressures correspond at all points; exist throughout the entire circumference of the article at but slightly spaced points and therefore have no tendency to distort or Vary the shape of the article.

At the same time, due to the slight angle of the slots, the members 22 themselves will be substantially locked in position against radial movement with respect to the supporting body I9 and/or the circumscribing work piece I3 and will resist any tendency to distortion of the work piece by lateral pressure thereagainst at circumferentially spaced points.

It will thus be seen that the article is properly, satisfactorily supported in its initial shape or form Without distortion and can thus be inserted, together with the support I9, in the throat of a suitable machine tool in a suitable tooling position, such as a centerless grinder, for example, where it may be rotated on its periphery-resting on the work rest I4 under rotational and pressure control of the regulating wheel I2 while a tooling or nishing operation is performed thereon by the grinding wheel I I. It is, of course, understood that in the performance of this tooling operation the pressure reacting against the outer periphery of the Work is suitably controlled either manually by the operator or by interposition of resilient mechanism in the machine tool adjusting mechanism, such that the aggregate exterior pressure on the work is maintained below a point which will cause displacement of the frictionally locked, yieldingly urged members 22.

Upon completion of the tooling operation the unit as an entirety is removedthe end stop retracted and the work piece progressively advanced axially with respect to the member I9, as indicated in Figure 5-the retaining members 22 yielding to permit of ready slipping off of the article,

An alternative form of construction, similar in general respects to that just described but adapted for exterior engagement with articles which are to be interiorly finished, is shown in Figure 6 where the sections Ilia. have the similar sockets 29a, the pressure members 22a actuated by the springs 23a. The essential difference in this form of construction is that the sockets 20a extend inwardly and break through the inner face of the members Ia and the telescoping or interiitting portions 29 and 39 of the collars have interengaged threads so that the sections may be screwed together to form a complete unit of desired length according to the linear dimension of the work piece to be supported thereby.

The work piece, as before, is introduced in a direction tending to compress members 22a against their backing springs, and retracted or withdrawn by a continuance of the same movement.

In Figures 8 and 9 there has been illustrated a modied form of the invention in which use is made of a multiplicity of resilient spiders, each having a hub portion 3| mounted on the centering stud 32 and held in suitably spaced relation with respect to each other by the collars or bushings 33. These spiders have the multiplicity of radiating spring fingers 34 provided with terminal rounded abutment portions, such as 35, which may be removably secured in position as by screws 36, the diametrical measurement from tip to tip of the members 35 preferably being slightly greater than the internal diameter of the work piece to be mounted thereon.

As before, the thin tubular work piece or sleeve I3 is slipped over the holding device formed by this multiplicity of spring spiders, which again interiorly support the work piece with equal pressures presented at a multiplicity of points. If desired, use may be made of a cap plate or abutment 31 adapted for intertting engagement with one terminus of the Work piece and centrally receiving the tensioning screw 38 engaged in socket 39 in the stud 32 for imparting an axial urge to the stud, tending to tension the individual spring fingers against lateral deflection on application of opposed radial pressures thereto which might otherwise produce relative axial movement of the hub portion of the device with respect to the peripheral spring urged abutments interfering with the eilicient reaction thereof.

By reference particularly to Figures 3 and 9, it will be noted that adjacent sections or units which make up the work engaging member are preferably disposed in opposite or staggered relation with respect to each other whereby maximum circumferential distribution of the balanced work supporting members is accomplished. It will be further noted that as respects all forms of the invention illustrated, the basic structural principles are the same and that in all instances the improved method of finishing tubular articles consists in uniformly supporting the article in its initial form without distortion by engagement therewith or" a multiplicity of supporting devices, each individually urged into engagement with the work piece yieldingly with a pressure insufficient to cause distortion of the work piece. It will be further noted that the process contemplates the maintenance of the members in work supporting` position by irictional resistance to their displacement, rather than by appreciable radial or axial pressures which might cause distortion so that the work piece is properly universally supported and while so supported is subjected to a tooling operation reacting on the surface opposite that so supported with a pressure below that which will cause an axial displacement of the supporting members, permitting of radial deection of the article, so that a true cylindrical or like surface may be produced on the article which will remain true in contour g after removal of the work piece from its holding or supporting member. In this connection it is to be particularly noted that gage measurements show that a work piece of the type here illustrated, in the absence of a supporting mechanism, may be grasped between the thumb and finger and deiiected to cause as much as onetenth of an inch variation or elongation of diameter by such pressure but when supported by the improved device of Figure 3, for example, will remain undefiected under maximum pressure than can be applied by manual gripping thereof.

In Figure l there has been shown, as applied to the end sections, such as ifi, a flexible annular ring 40 clamped in position as by the washer 4l which in Figure l0 is shown as a'support securing member although, if preferred, the same could be made a part of the terminal discs 24 and 25, for example. Both the member It and the member il are shown as formed with the cannelures or grooves l2 and 43 respectively of size to receive the deflected peripheral exterior of the member iii as clearly shown in Figure 10.

It will thus be understood that as the work piece I3 is slipped into position the members 40 at opposite ends of the holder will be correspondingly deiiected, the one lying over into groove 42 while at the opposite end the corresponding member will interiit with groove t3 with the result that a tight seal is provided between the interior of the work piece and the exterior of the holder, eliminating the possibility of grinding grit, chips or the like working into the holder and interfering with satisfactory operation of the individual yielding work engaging members.

It will, of course, be understood that by reversal of parts a corresponding sealing action may be effected in connection with the internal chuck device shown in Figure 6.

What is claimed is:

1. An internal bracing member for support during machining of a Work piece of iiexibility distortable by the necessary pressure of the machining operation, comprising a work piece supporting member having a plurality of pressure members supported for joint axial and radial movement for engagement with the work piece, and means for individually, yieldingly urging said members into engagement with the work piece under a pressure insufficient to distort said work piece.

2. A device of the character described comprising a plurality of short tubular sections each having a multiplicity of angularly disposed bores formed therein, laterally breaking through one of the cylindrical walls of the section, work supporting members slidably mounted within said bores, means for yeldingly actuating the supporting members in the bores in a direction to cause the supporting members to project beyond the walls of the tubular members, and means for maintaining the tubular members in terminal intertting relation whereby a continuous tubular work support is provided.

3. A device of the character described comprising :a plurality of short tubular sections each having a multiplicity of angularly disposed bores formed therein, laterally breaking through one of the cylindrical walls of the section, work supporting members slidably mounted within said bores, means for yieldingly actuating the supporting members in the bores in a direction to cause the supporting members to project beyond the walls of the tubular members, and means for maintaining the tubular members in terminal intertting relation whereby a continuous tubular work support is provided, said yielding means comprising compression springs each terminally bearing at one end against one of the slidable work engaging members and at the other end against an adjacent tubular section, substantially as and for the purpose described.

4. A work support for a iiexible tubular article comprising a main supporting member, a multiplicity of individual resiliently mounted contact members disposed in longitudinally radially staggered relation and adapted for simultaneous engagement with one of the peripheral walls of the tubular article, individual means for yieldingly urging the respective work engaging members against the Work with a non-distorting pressure, and means preventing relative axial movement of the main support member and the Work piece.

5. A device of the character described comprising a body portion having a multiplicity of separate individually actuable work engaging members projectable with respect to the body portion for engagement with a work piece, and terminal exible sealing members carried by the body portion and projecting circumferentially with respect thereto in excess of the potential projection of the work engaging members whereby said yieldable terminal devices will interlock with the supported face of a work piece to prevent access of tooling produced chips to the Work supporting members. 6. A device of the character described comprising a body portion having a multiplicity of separate individually actuable work engaging members projectable with respect to the body portion for engagement with a work piece, and terminal flexible sealing members carried by the body portion and projecting circumferentially with respect thereto in excess of the potential projection of the work engaging members whereby said yieldable terminal devices will interlock with the supported face of a work piece to prevent access of tooling produced chips to the work supporting members, said body portion being formed with circumferential cannelures adjacent the flexible sealing member permitting lateral iiexure of the sealing member substantially as and for the purpose described.

GEORGE W. BINNS. FREDERICK J.` THELER.

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