US1640543A - Bushing and method of forming the same - Google Patents

Description

192 Aug 7 B. J. GUDGE BUSHING AND METHOD OF FORMING THE SAME 2 Sheets-Sheet 1 Filed Nov. 28, 1919 3 INVENTOR Be/y'amim/ 621 6 WITNESSES:

ATTbRNEY I 1,640,543 v 1927' B. J. GUDGE BUSHING AND METHQD OF FORMING THE SAME Filed Nov. 28, 1919 2 Sheets-Sheet 2 I I?! m m x m WITNESSES: INVENTOR 1 I ATTORNEY 'IBENJ'AMIN J. GUDGE, OF WILKINSBURG,

PATIENT OFFICE.

PENNSYLVANIA, ASSIGNOR TO WESTING- HOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYL- VANIA.

BUSHING AND METHOD OF FORMING THE SAME.

Application filed November 28, 1919. Serial No. 341,606.

My invention relates to bushings and to methodsof manufacturing them and it has, for its primary object, the provision of an insulating bushing formed with an integral been satisfactory for some purposes.

flange in such manner as to ensure a strong structure throughout and, particularly, at the juncture of the body portion and the flange. I

One of the objects of my invention resides in constructing a bushing of the above mentioned character from superimposed layers of fibrous sheet material, such as paper,

cloth, duck and thelike impregnated with a binder which will give the finished product the requisite strength, permanency of form and insulating qualities. Various binders, such as shellac, phenolic condensation products, copal, casein and like shellac substitutes may be employed but I prefer to employ a binder which may be hardened by application of heat and pressure, such as bakelite.

Various methods have been practiced in the manufacture of bushings from sheet material and a binder. and such bushings have For example, by onemethod, a-tubular body, comprising superimposed convolutions of fibrous sheet material associated with a proper binder, has been disposed about a cylindrical mandrel with one end of the convolutions in engagement against one of a plurality of annular sheets of similar material superimposed upon the bottom plate of the mold, and mold elements have been assembled about the sheet material thus disposed to compact it and harden the binder. The result has been an insulating bushing comprising a tubular body portion havinganintegral outwardly directed flange at one end. This bushing has possessed the desired insulating properties but has been mechanically weak at the juncture of the tubular portion of the bushing and its flange.

Another method, which has been practiced with somewhat more success, com rised superimposing'a plurality of discs of brous sheet material associated with a binder and provided centrall with slits about a cylindrical mandrel orced through the slitted portions of the discs. The discs and mandrel were then disposed upon the bottom portion of a mold,the tubular body portion of superimposed layersof similar sheet material treated with a binder was placed about the mandrel and the material thus assembled was subjected to heatand pressure through the employment of suitable molding elements to compact the material and harden the binder. By this method, a somewhat stronger structure at the joint of the tubular body portion and *flange of the bushing was produced. However, this jointhas been found to betoo weak in some instances and is also liable to be too bulky.

, With these ditfic'ulties in View, my present invention comprehends the provision of a method of forming flangedbushings by which an extremely strong and compact joint is formed between the bushing proper and its flange so .that all parts of the bushing possess substantially-uniform strength and thickness. j

A still further object of my invention comprises a method of manufacturing bushings of the foregoing character which may be simply andrapidly practiced and which will not requlre any unusual skill upon the part of the operators. V

With these and other objects in view, Fig.

1 is a perspective View of a'bushin which may be constructed by the practice 0 my invention; Fig. 2 is a plan view of a mold which may be employed in forming a bushing, showing a bushing in plate; Fig. 3 is a sectional view of the mold and its enclosed bushing, taken along the line 33 of Fig. 2, Fig. 4 ,is a plan View, parts being broken away for the sake of-clearness, illustrating the method of assembling the fibrous sheet material according to my invention, Fig. 5 is a plan view of a strip of material slitted in accordance with my'invention, and Fig. 6 is an exploded view of thebushing shown in Fig. 1. r i

In Fig. 1 of the drawing, I have illustrated a bushing, constructed in accordance with my invention, which may comprise a tubular body portion 1 formed, at one end, with a laterally directed peripheral'flange 2. The tubular body portion 1 may be cylindrical in form but it preferably tapers slightly from its flanged end, when the use to whichit is to be put will permit it, in order to facilitate the molding operation.

In order to ensure a .clear and accurate understanding of my invention and the method of practicing it, a general knowledge of a mold suitable for forming the bushing is essential, and reference is, therei fore, to Figs. 2 and 3 of the draw-' Bastian, Se t. 8, 1919, Serial 'No. 322,542,

I strength.

and assigns to the Westinghouse Electric & Manufacturing Company and relating to molds.

Briefly stated, a mold suitable for, em-

ployment in the practice of my inventionmay comprise an annular bottom plate 3, the central opening of which may snugly receive the enlarged lower end 4; of acentering pin or mandrel 5.. This centering pin or mandrel ma cross-section and may taper slightly towards its up er end. (Jo-operating with the bottom p ate and centering pin are three or more splits 6, so formed that, when assembled about the centering pin, with their opposed faces abutting each other, they provide a substantially frusto-conical body forming a continuation of the peripheral wall of the bottom plate, which is correspondingly inclined. A matrix or press ring 7 1s provided having its inner face inclined to engage uniformly against the inclined outer faces of the splits and bottom plate so that, when it is lowered about the upper portions of the splits and forced downwardly to the position shown in Fig, 3, it will force the splits inwardl 7 and downwardly against material dispose between them and the mandrel and bottom plate to uniformly and strongly compact the material.

My present invention comprises animproved method of shaping and fitting fibrous sheet material, of any desired character .and associated with any suitable binder, in such manner that it may be disposed within a mold of the character above described and there subjected to pressure and such other treatment as may be required to compact the material and harden the binder to produce a body havin the desired permanency of shape and While various binders may employed and diflerent sheet materialsmay be utilized, I prefer to form bushings :from cotton duck which has been impregnated 'with a phenolic b condensation product in solution and'from which all solvent has been driven-in such manner as to leave the binder in a solid but moldable condition. In otherwords, when expelling the solvent, care should be taken that the temperature does not reach such a point as to convert the binder to its final solid and substantially insoluble and infusible condition. I

Sheet material so treated may be cut to ,E id a strip equal in width to the comined length of the body portion of the uniformity of bushing and the radial dimension of the flange, and the strip thus provided may be slitted at suitable intervals, along and at right angles to its longer edges, to provide a plurality of tongues equal in length to the radius of the flange. Additional sheet material may be cut to provide a plurality of annular layers of the external diameter of the desired bushing flange and having central openings of diameters varying from that of the internal diameter of the desired bushing to a diameter but slightly less than that of the desired flange. Obviously, the.

preparation of the slitted sheet and of the several annular layers may be performed by 'unskilled labor. preferably be of circular 4 WVith the material thus prepared, the bushing bod may be assembled by winding the slitted s eet to form a tubular body 8 of superimposed layers of. treated material, reference being had to Fig. 4 of the drawings. The tongues '9 formed at the slitted edge of the sheet,so wound, may be bent outwardly, and each layer of tongues arranged. alternately to cover the openings between the tongues in the previous layer, as shown and may be disposed upon an annular bottom sheet 10 having the mternal diameter of the corresponding diameter of the. desired bushing. A plurality of annular layers 11 of l graduated width may then be concentrically disposed'in superimposed relation upon the laterally projecting tongues 9, after which a top layer 12, having a central opening fitting snngly about the tubular portion 8, may be applied. The snug engagement of the tubular portion 8 in the opening of the top layer 12 serves to prevent displacement of any of the various layers and also prevents the tubular portion 8 from becoming unwound. B interposing a suitable number of the intermediate layers 11 of proper graduated widths, I provide additional material, to compensate for the shortage of material in the outer portion of the flange, so that a flange of substantially uniform thickness of material is provided. I

\Vhen ,the bushing body has been as,- sembled, as above described, the tubular portion ma be slipped over the centering pin 5 of a mo d until the flan e portion rests upon the bottom plate '3. T e s lits 6 may then e positioned about the tu ular portion of the bushing and in engagement with the upper layer 12 of the flange portion thereof, and the matrix 7 of the mold, may be lowered about the upper portions of the s lits. The assembled mold, with the cue osed bushing, may then be disposed in'a suitabl heated ress which may be actuated to simu taneous y heatthe various mold sections and to force the matrix 7 downwardly to the position shown in Fig. 3 ofthe drawings. The movement of .the matrix forces the splits inwardly and downwardly to strongly and lUU mandrel thereof. The combination of heat uniformly compact the superimposed layers of fibrous material, both against the bottom of the mold and against the centerlng pin or and pressure thus provided will firstsoften and then harden the binder of the sheet ma- 'te1 'ial,if a phenolic condensation product I or other adhesive hardeningupon the application of heat is employed.

By practicing my invention. as above set forth, I obtain a bushing of the desired permanency of form and insulating qualities which, furthermore, possesses an unusual and 'highly desirable degree of strength. The

strength obtained may be attributed to the factthat the-tongues .9,which are integral I with the sheet material forming the bodyof the mold, project laterally to the outer ."edge of the bushing flange and are locked firmly between the several layers compflis- I ing the main portion of the flange.

- combined with the fact that the graduated intermediate layers ensure a substantially uniform thickness of material throughout the width of the flange, ensures not only a strong flange but a strong joint between the flange and body of the bushing.- Furthermore, there is no undue thickening of the material about the joint as has been the case the past.

,While I'have described my invention in considerable detail, it will be appreciated that it is susceptible of various modifications. For example, the opposite end of the, sheet forming thebo-dy of the bushing may be slitted to provide tongues, and a second flange may be formed, in identically the same manner as the first, at the'other end of the bushing. As this is merely a dupli cation of the method above described and as n the application of A. J. Bastian. hereinbefore referred to, discloses amold suitable for forming a bushing with flanges at both' ends, any further description orzillustration of this modification of my present case is believed to'be unnecessary.

Although I have disclosed a preferred embodiment of my invention, it will, of course, be appreciated that I reserve the right'to.

make any changes, both in the materials employed and in the method practiced in assembling and treating them, which may come within the scope of the claims or which the prior art will permit.

I claim as my invention 1. Thegnethod of forming flanged tubular objects that comprises forming a tubular body of moldable material with outwardly projecting-portions, disposing moldable material against the projecting portions and molding the material thus assembled to compact and harden it into a tubular structure provided with a flange formed by the proecting portions of the tubular body and the materlal disposed against them.

. 2. The method of forming flanged tubular objects that comprises forming a tubular body of fibrous sheet material, associated with a binder and provided with integral outwardly projecting portions, disposing 7 fibrous sheet material impregnated with a binder against the outwardly projecting portions and treating the body thus assembled to compact the material and to harden the binder.

3. The method of forming flanged tubular objects that comprises forming a tubular body portion of fibroussheet material associated with a binder and provided, at one end, with outwardly directed radial tongues,

impregnated with a like binder against the opposite faces of the tongues and subject ing the entire body thus assembled to heat and pressure in a mold to compact it and harden its binder. I

v 5. The method of forming flanged tubular objects that comprises providing slits in one edge of a sheet of fibrous material impregnated with a binder to provide a series of tongues, winding the sheet to provide a tubular body comprising a plurality of superimposed convolutions, bending the tongues outwardly with respect to the body, disposing aplurality of annular layers of sheet ma terial impregnated with a binder. against the opposite faces of the tongues and treating the body thus assembled under pressure in a mold to compact it and harden its binder.

6-. The method of forming flanged tubular objects that comprises forming a tubular body of superimposed layers of fibrous sheet material impregnated with a binder and provided, at one end, with outwardly directed,

integral tongues, disposing a plurality of annular layers of fibrous sheet material impregnated with a binder against the faces of the tongues, all of the layers being of uniform, external diameter and certain of the layers being of graduated internal di-v ameter and. treating the material thus assembled in a mold the binder.

7. A flanged tubular object comprising a to compact it and harden.

tubular body of superimposed/ layers of fibrous'material provided, at one end, with outwardly directed integral tongues and annular layers of fibrous sheet material disposed against the faces of the tongues for co-o erationtherewith' to form a flange, all of t e la *jers being associated with a hard.- ened bin er.

8. A flaned tubular object comprising a tubular b0 y of superimposed layers of fibrous material provided, at one end, with outwardly directed integral tongues andannular layers of fibrous sheet material disposed against the faces of the tongues for (lo-operation therewith to form a flan e, all

. of the sheet material being impregnate with a heat hardened binder.

9. A fian ed tubular object comprising a tubular body of su rimposed layers of fibrous material provided, at one end, with outwardly directed integral tongues and annular layers of fibrous sheet material disposed against the faces of the tongues for 00- operationtherewith to form a flange, all of the layers being impregnated with a hardened phenolic condensation product.

1n testimony whereof. I have hereunto subscribed my name this 21st day of November, 1919,

BENJAMIN J. GUDGE,

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