Title:
Method of making bushings
United States Patent 2177584


Abstract:
This invention relates to the finishing of hollow bodies, and more particularly bushings, to gauge, and provides a method of and means for accurately finishing a semi-' or rough-finished hollow body, such as for example a bearing bushing; and that in an extremely simple manner. For the purposes...



Inventors:
Franz, Salansky
Application Number:
US14153037A
Publication Date:
10/24/1939
Filing Date:
05/08/1937
Assignee:
Franz, Salansky
Primary Class:
International Classes:
B21K1/04
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Description:

This invention relates to the finishing of hollow bodies, and more particularly bushings, to gauge, and provides a method of and means for accurately finishing a semi-' or rough-finished hollow body, such as for example a bearing bushing; and that in an extremely simple manner.

For the purposes of the present invention it is quite immaterial by what method or in what manner the semi- or rough-finished bushing is made. Bushings finished to gauge by the present method are not only dimensioned with the required degree of accuracy but also have a smoothness of surface which can not be obtained even by turning and grinding. At the same time the required rounding-off of the edges of the bushing is also effected, so that no subsequent work or touching up is required, and the bushing is discharged from the device in a condition ready for immediate use.

The method according to the invention consists in securing the hollow body, bushing, or the like, between a gauge ring and a gauge mandrel, and subjecting it to a pressure which brings about permanent deformation. This method is particularly well suited for the finishing of longitudinally slotted bushings with which the pressure is exerted upon the end surfaces of the bushing, and the material allowed to flow solely in a circumferential direction with diminution or 80 complete closing .up of the longitudinal slot.

The device serving for the carrying out of this method consists of a gauge ring mounted on the table of a press and a gauge mandrel preferably secured to the die of this press.

85 A further object of the invention is to provide safeguards of a special nature, against the unintentional opening of bushes provided with a longitudinal joint or against the coming apart of the parts of bimetallic bushes consisting of two different metals. The method is characterized in this that the bush parts to be safeguarded against coming apart are so pressed one to each other or into each other that in the connecting zones in lines parallel to the axis of the bush the parts to be connected together are alternately one above the other.

The invention is illustrated by way of example in the accompanying, drawings which form part of this specification, and in which: Figs. 1 to 3 show diagrammatically the principle of the invention, Fig. 1 showing a semifinished bushing in side elevation, Fig. 2 the parts involved in the pressing operation in longitudinal section, and Fig. 3 the bushing finished to gauge in end elevation.

Figs. 4 and 5 show the complete device in sectional elevation, with the pressing die lifted and with the pressing die in the lowered position, respectively.

Fig. 6 shows a modification of a detail of the construction.

Figs. 7 to 9 show a method for making bushes with a special joint, Fig. 7 showing a blank, Fig. 8 a side elevation of a not finished bushing and Fig. 9 of a finished bushing. Figs. 10 to 15 show methods for making bushes consisting of two metals, Fig. 10 being a side elevation and Fig. 11 an end elevation of the outer shell, Fig. 12 illustrating one phase, Fig. 13 a second phase and Fig. 14 a third phase of the method for uniting the two metal shells, Fig. 15 being an end elevation of the finished bimetallic bush.

Fig. 1 shows a semi-manufactured bushing I with a longitudinal slot 2, produced for example by rolling up a strip sheet iron. Experience has shown that as a result of this method of manufacture on the one hand the end surfaces of the bushing are uneven or wavy, and on the other hand the envelope is slightly "waisted" in the middle, so that the bushing is not fit for use as an accurate bearing lining and requires subsequent machining to obtain accurately cylindrical peripheral surfaces and plane end surfaces.

According to the invention, as shown in Fig. 2, the bushing I is Inserted in a gauge ring 3 the inside diameter of which exactly corresponds to the desired outside diameter of the finished bushing. On the die of the press there is provided a gauge mandrel 4 the diameter of which exactly corresponds to the required internal diameter of the finished bushing. On the die of the press there is further provided a shouldered-out portion 5 of which the shoulder breadth corresponds to the thickness of the bushing, and which serves for the transmission of the pressure to the end surface of the bushing and at the same time for the production of a perfectly plane and smooth end surface. Thus, seeing that both the .peripheral surfaces and also the end surfaces of the bushing are strictly defined or delimited by the gauge ring 3 and the mandrel 4, the material of the bushing can only become displaced in a circumferential direction, with the result that the breadth of the slot 2 is diminished, or, if the pressure exerted be sufficiently powerful, this slot becomes completely closed up, A completely closed bushing produced in this manner, and havSing the exact final dimensions required and per- KB fectly smooth surfaces, is shown in end elevation in Fig. 3 of the drawings.

The gauge ring 3, the upper inside edge of which is preferably rounded off to facilitate the insertion of the bushing, is attached to the table I of the press in a suitable manner. The die ' of the press carries the gauge mandrel 4 the lower edge of which is chamfered off to facilitate centering, and which is provided with a shouldered-out portion 5 corresponding to the thick- ness of the bushing. The transition from the mandrel 4 to the shouldered portion 5 is rounded out or throated as shown at 6 to effect the rounding off of the inner edge of the bushing.

lg The device may be so constructed that both the gauge ring and the mandrel are secured to the table of the press.

To the die 7 there is further attached a crosshead 8 which is rigidly connected, by means of two bolts 10, to a second cross-beam S disposed beneath the table  of the press. In an aligned bore f4 in the gauge ring 3 and in the table I I of the press there is guided an ejector 12 of which the end surface serves to support the lower end of the bushing I, and which has a bore 13 for the guiding of the mandrel 4. The ejector 12 is further provided with a shoulder 8I which is supported against the bottom i5 of the bore 14 in the table of the press when the die 7 de80 scends. Integrally with the ejector i2 there is also formed a guide pin 17 adapted to extend downwards through the table of the press and to be lifted, when the die 7 ascends, by the crossbeam 9 which participates in the movement of ,g the die.

Briefly, the pressing operation is carried out as follows: With the die 7 of the press in the elevated position the bushing I is inserted in the gauge ring S. As the die descends, the bushing I resting upon the ejector 12 is likewise lowered bodily into the bore of the gauge 3, since the ejector 12 rests with its pin 17 upon the cross-beam 9.

As soon as the shoulder 16 on the ejector 32 bears against the. bottom 15 of the bore 14 the mandrel 4 travels through the bore of the bushing and enters the bore 3 of the ejector 12, being thereby accurately centred. The shoulder 5 then presses upon the upper end surface of the bush5g ing 0, the throat 6 thereby effecting the rounding off of the inner edge of the bushing. This phase is shown in Fig. 5. of the drawings.

As.the die 1 of the press ascends the mandrel 4 is first withdrawn from the socket 13 and from the bushing, the bushing being left in the bore of the gauge ring S. Not until the lower crossbeam 8 has been lifted through the distance 19 does it begin to lift the ejector 12 also, and then the bushing I is ejected from the gauge ring and can be removed. In order to equalize and to smooth the other end surface of the bushing, and to effect the rounding-off of the other inside edge, the bushing is then turned round and inserted in the reversed position in the gauge ring. The above-described pressing operation is then repeated in the same manner as before, after which the bushing is accurately finished on all its surfaces as regards dimensions and roundingsoff.

As shown in Fig. 6, the ejecting of the bushing I may also be effected by means of a compressed spring 20 which is supported in the lower part 21 of the table II of the press, and which presses for example against a collar 22 on the guide pin 7s 1I thereby forcing the ejector upwards when the die of the press ascends. With this form of construction of the ejector, the bushing leaves the gauge ring 3 simultaneously with the mandrel 4, with the result that it is possible for the bushing to remain adhering to the mandrel. On the other hand if the die ascends by itself first, the bushing remains behind in the gauge ring, since the adhesion between the gauge ring and the bushing, after pressing, is generally greater than the adhesion between the bushing and the gauge mandrel 4.

In Fig. 7 there is shown a blank from which a unimetallic bush with longitudinal joint is to be produced by rolling up and finishing to gauge by the method described. The bush I is provided at one edge intended to delimit the slot, with a tab 23 preferably of rectangular shape. At the opposite edge, on a level with the tab, there is provided a recess 24 the width of which, measured in line with the delimiting edge 25 is equal to the breadth of the rectangular tab 23. The recess 24 widens out towards the inside, so that it is of trapezoidal or dove-tail shape. After rolling up, the blank presents the shape shown in Fig. 8, with the inner angles of the recess 24 not filled out or not completely filled out by the tab 2.. The operation of finishing to gauge is then effected by pressure exerted upon the end surfaces. Owing to the flowing of the material which can only yield circumferentially since it is clamped between an outer and an inner shapedetermining cylinder,, the result is thereby achieved that the trapezoidal recess 24 is completely filled out by material pertaining to or adjoining the tab 23 (Fig. 9). It is thereafter quite impossible for the bush to come apart through opening of the joint owing to circumferential forces.

In Figs. 10 to 15 there is shown a further constructional example, it being assumed that the bush is of the bimetallic type. Referring to Fig. 10, a plan view of which is shown in Fig. 11, the material for the outer shell 26 of the bush is produced for example by rolling up, in which case a relatively wide gap or joint 27 may be left open. The inner sleeve or lining 28 may likewise be produced by rolling up, and this lining may then be inserted in the outer shell 26, as shown in Fig. 12, the length of the lining 28 being considerably greater than that of the shell 26 and preferably 5 equal to the sum of the length 29 of the shell 26 and twice the thickness 30 of this shell. The lining 28 may be obtained, like the shell 26, by a rolling up operation. It is equally possible, however, to use, both for the shell 26 and also for the lining 28, or for one of the two, tubing as starting material. In the constructional example shown the lining sleeve 28 is also provided with a longitudinal joint 31 which may be disposed for example obliquely to the longitudinal axis of the bush. As shown in Fig. 13, axial pressure is then exerted upon the lining sleeve by means of two conical pressing dies or the like 32, 33, with the result that the projecting ends of this sleeve are spread and turned over as shown in this figure of the drawings. A semi-finished bush obtained in this manner may then be inserted in the.gauge apparatus and treated by pressure exerted upon its end surfaces in accordance with the method described whereby there results the bush shown in longitudinal section in Fig. 14 of the drawings. In this bush both the inside and the ends consist of one and'the same material.

In order to obtain a more intimate connection between the two sleeve members one of these latter may be provided with notches 34 or the like into which material of the other member becomes forced during the pressing operation, so that the two members become firmly anchored together and locked with absolute certainty against rotary movement relatively to each other.

Finally, Fig. 15 shows in end elevation the final product in the case of a bimetallic bush in which both the shell 26 and the lining 28 have a longiStudinal joint, these longitudinal joints 21 and 35, respectively, being with advantage disposed diametrically opposite each other, so that, more particularly when the joint 35 is disposed obliquely to the longitudinal axis of the bush, the effect obtained is similar to that of a solid, i. e., one-piece, bush. It will be obvious that one of the two sleeve members, and more particularly the inner, may be in the form of a jointless tube from the outset.

It is also possible to employ the method shown by way of example in Figs. 10 to 14 in such a manner that the shell 26 is folded over the end surfaces of the lining sleeve.

In the case of bimetallic bushes the described method may be combined with'that described by way of example for a unimetallic bush with reference to Figs. 7 to 9 of the drawings.

It is to be understood that the invention is not restricted to the examples described and shown, but that the same may be equally well applied to the finishing of bushings of non-round or polygonal cross-section, and of other hollow bodies.

Having now described my invention I claim: 3 1. The method of making rings, which consists in placing one split ring inside another with their opposed surfaces in contact, bending the ends of the inner ring on the ends of the outer ring and while holding the material of the rings against movement radially, applying pressure to the ends of the rings to cause the material thereof to flow annularly, thereby closing the gaps at the splits without substantially altering the thickness of the ring walls and uniting the rings into an integral whole.

2. The method of finishing to gauge one-piece bushings which are formed by bending a flat bar to tubular form with the adjacent edges spaced a substantial distance apart to constitute a longitudinal gap, said method comprising the insertion of the bushing with the gap open into a suitable die having an inside diameter equal to the desired outside diameter of the bushing, and finally exerting such pressure on the end faces Sof the bushing that the material flows and the slit is diminished in width to the extent desired.

3. The method of making bushings that are composed of an outer longitudinal slit tubular body and an inner longitudinal slit lining body, said method comprising the forming of said bodies individually from flat bar iron by bending the same into tubular form, inserting the lining body into the outer body with the slits open, the lining body being made of a greater length axially of the bushing than is the outer body, conically widening the ends of the lining body to project laterally over the ends of the outer body, then placing both bodies assembled in a die having an inside diameter equal to the desired outside diameter of the bushing, inserting a gauge mandrel into the lining body, and finally applying such pressures to the end faces of the bushing bodies that the material flows and, the slits are diminished in width to the degree desired and the lining bodies are snugly fitted to the outer bodies' contacting surfaces. 4. The method of finishing to gauge one-piece bushings which are formed by bending a flat bar to tubular form with the adjacent edges spaced a substantial distance apart to constitute a gap, the volume of which gap has such relation to the mass of the bushing that when the bushing is finished the reduction in its length to finished " state results in a closure of the gap, said method consisting in inserting the open-gap bushing into a suitable die having an inside diameter equal to the desired outside diameter of the bushing, and on a mandrel whose outside diameter is equal to the desired inside diameter of the bushing, and exerting such pressure endwise on the bushing that the metal flows as the length of the bushing is brought down to the desired finished length and the metal of the bushing's *mass is caused to flow circumferentially into the gap to diminish the gap to the point of complete closure, without substantially changing the density of the metal.

5. The method of finishing a longitudinally split tubular body, the walls of the split being initially spaced apart, which consists in applying pressures to the respective ends of said body in opposite directions along the axis, while holding the mass of said body from moving inwardly or outwardly at right angles to the axis, said pressure being exerted upon the end faces of the tubular body in such manner that the material is permitted to flow in a circumferential direction causing diminishing of the width of the longitudinal split to the point of complete closure as may be desired.

6. The method of finishing a tubular body having a longitudinal split or gap, which consists in placing said body in a gauge ring, placing a gauge mandrel in said body and applying force to the ends of the body between the gauge ring and the gauge mandrel in the direction of the axis of the body to displace the metal of the body and cause it to flow circumferentially and thereby diminish the gap to the point of. complete closure, without substantially changing the density of the metal. FRANZ SALANSKY.