US1798305A - Method and means for preventing electrolytic action - Google Patents

Description

March 31, 1931. H. CHRISTOPHERSEN 1,798,305

METHOD AND MEANS FOR PREVENTING ELECTROLYTIC ACTION .3 SheetsSheet l Filed Sept. 29. 1927 March 3l, 1931. H. CHRISTOPHERSEN 19793,:395

METHOD AND MEANS FOR PREVENTING ELEGTROLYTIC ACTON Filed sept. 29, 1927 Sweets-sheet 2 W5. v W 7 /y y Z5 '/NVENTo/efwww [NVENTOR A TTORNEY H. CHRHSTPHERSEN METHOD AND MEANS FOR PREVENTIHG ELEGTROLYTIG ACTION Filed Sept. .'5 Sheets-Sheet 3 March 31, 193,11.

Patented Mar. 31, 1931 UNITED YSTATES PATENT OFFICE HERBERT CHRISTOPHERSEN, 0F EAST ORANGE, NEWJERSEY, ASSIGNOR TO REVERE RUBBER COMPANY, OF CHELSEA, MASSACHUSETTS, A CORPORATION OF RHODE ISLAND METHOD AND MEANS FOR PREVENTING ELECTROLYTIC ACTION f Application led September 29, 1927. Serial No. 222,916.

This invention relates to an improved method of and means for protecting parts from electrolytic action. More particularly it relates to an improved method for sealing the ends of a rubber sleeveupon a shaft, rod or similar part whereby water is excluded from the part, and to the resulting article.

This application is a continuation in part of my co-pending application Serial No. 139,251, filed October 4, 1926.

A serious diliiculty in the use of propeller shaft assemblies has been that by reason of electrolytic action, the shaft assembly members, such as shafts, struts, etc., quickly become pitted and weakened, and this action is particularly rapid at points where the member is in direct contact with a dissimilar metal. The shafts are ordinarily made of steel and provided with bearing sleeves of bronze or similar metal, which sleeves are disposed in the bearings within the stern tubeof the vessel. Itis impossible to prevent the leakage of water through the bearings into the stern tube, and as a result, the above described electrolytic action takes place within the stern tube.

An obJect of the invention is to provide a protective coating for propeller shafts and other members such as struts or braces which will prevent access of water to the same and thereby avoid electrolytic action. Another object is to provide a permanent and water tight union at the ends of the protective coating. Other objects will appear from the detailed disclosure.

Referring to the drawings:

Fig. 1 is a perspective view of the propeller and the propeller guard of a ship with parts of the stern of the ship broken away to show the shaft and bearings therefor in transverse section;

Fig. 2 is a side elevation of the propeller shaft with parts thereof broken away and in section;

Fig. 3 is a cross-section taken on the line 3-3 of Fig. 2;

Fig. 4 is a front elevation of one forni of band for gripping the rubber tube;

Fig. 5 is a side elevation of the band;

Fig. 6 is a front elevation of the band showing the fastening means for the end of the band;

y Fig. 7 is a front elevation of a modification of the band;

Figs. 8 and 9 are perspective views of the fastening elements for the modified band;

Fig. 10 is a side elevation of a rubber covered strut prior to vulcanization;

Fig. 11 is a section upon the line 11-11 of Fig. 10 showing the rubber covered strut subsequent to vulcanization; Y

Fig. 12 is a detail side eleva-tion of a strut with parts broken away and illustrating the manner of assembling the sleeve upon the strut; and t Fig. 13 is a section upon the line 13-13 of Fig. 1l.

Referring to the drawings, and particularly to Figs. 1-9 inclusive, reference numeral 1 designates the stern of a ship in which is rigidly secured the propeller shaft assembly members comprising the stern tube 2 which is held in position by shoulders 3, t and 5 which engage the walls of the ship. An inboard bearing sleeve 6 made of suitable material such as bronze is secured Within the stern tube together with an aft or stern bearing 7 which is formed for example of lignuin vitae. The stern bearing 7 is enclosed in a bronze housing 8. Both the housing 8 and the stern bearing 7 abut against a shoulder 9 upon the stern tube 2. A cover plate 10 formed of bronze or other suitable material overlies their outer end portions. Extending through the inboard and stern bearings in spaced relation to the stern tube is the propeller shaft 11 which carries rigidly secured thereto composition bearing sleeves 12 at those portions which contact with the bearings 6 and 7. The composition bearing sleeves 12 may be made for exampleof brass or bronze and ordinarily are secured to the shaft 11 by shrinking them thereon. The outer end of the shaftll is tapered at 13 and a propeller wheel 14 is held thereon by means of a nut 15 which is threaded on tothe end of the shaft.

Leakage of water commonly occurs through the stern bearing and the water accumulates between the stern tube and the (ill propeller shaft. Electrolytic action results, causing rapid deterioration of the propeller shaft, usually most rapid at the portions immediately adjacent the bearing sleeves 12. In order to exclude the water between the stern tube and propeller shaft from direct contact with the shaft and thereby prevent pitting of the shaft caused by electrolytic action, a sleeve 11 of rubber composition is formed about thehshaft completely covering same, and it is particularly desirable that the ends of the sleeve be tightly and permanentlyv secured.

The bearing sleeves 12 are so formed at their adjacent ends as to facilitate the connection thereto of the rubber sleeve in a permanent and water tight manner. Each sleeve 12 is provided with a reduced extension in the form of steps 15 and 19, which steps are provided respectively with the annular grooves 17 and 20. Between the step 19 and the main body of the sleeve, a shoulder 21 is formed which is preferably a vertical one, while between the steps 15 and 19 and at the end of the step 15 there are formed the respective bevelled or inclined shoulders 13 and 16. The number and size of these stepped portions may be varied as desired.

Instead of the annular recesses 17 and 20, a plurality of localized recesses which do not extend entirely around the sleeves 12 can be provided.

In the operation of encasing the shaft 11 with rubber composition, one or more coatings of rubber cement, either vulcanizable or unvulcanizable, are applied to the shaft and a strip of the composition of the approximate thickness of the shoulder 16 is wrapped around the same to form a tube or sleeve 22 of approximately the same thickness as the extension 15 with the ends of the sleeve abutting the shoulders 16. The tube 22 is rolled and stitched into intimate contact with the cemented shaft. A band 23 of metal is se cured around the rubber tube 22 adjacent each end thereof and if desired at intervals throughout its length to clamp the tube to the shaft 11. The band is provided with a plurality of perforations 25 which may be transversely elongated or otherwise shaped as desired. In its preferred embodiment the band is cut away adjacent one end to form an elongated slot 26 with arms 27 at either side thereof. The end of the band is bent back upon itself at about the middle portion of the arms 27 and secured to the body of the band by the rivet 2S, thus forming loops 29. Adjacent its opposite end the band is cut away at the sides to leave a connecting tongue 30 in the middle thereof, which is of a width to fit within the slot 26. This end of the band is bent back upon itself at the middle of the tongue and a rivet secures it to the band leaving a loop 31. lVhen securing the tube of rubber composition to the shaft the band is wrapped around it with the loop 31 fitting between the loops 29. A wedge 32 is then driven through the loops and serves to draw the ends of the band together thereby tightening the band in place. lVhen a wedge is used of sufficient length to protrude from the loops 29, the ends can be bent back to function as locking means to prevent the wedge from slipping loose.

Iaving secured the rubber tube 22 in position, a second strip of rubber composition of a thickness about equal to that of the shoulder 18 is wrapped around the rubber tube 22 to form the tube 33, the ends of which overlie the steps 15 and abut the shoulders 18. The tube 33 is preferably rolled and stitched into place. A metal band 23 is positioned over the tube opposite the annular groove 17 and is clamped in position. In the embodiment illustrated in the drawings a third tube V 3st of rubber composition of a thickness less than that ofthe shoulder 21 is placed over the tube 33 and step 19 is preferably rolled and stitched, and is secured in place by a band 23. Narrow tapering strips 457 of rubber composition are wrapped around the ends of the outer band abutting against the shoulders 21 and terminating substantially flush with the surfaces of sleeves 12. Preferably cement is applied to the steps 15 and 19 before applyine` the rubber sleeves 33 and 34e.

The pressure which is applied to the band 23 when driving the wedge 32 into place is preferably sullicient to cause A[low of the rubber composition into perforations 25 and into the grooves or recesses 17 and 20. Vulcanization causes complete flow of the rubber into the same so that the completed sleeve of rubber contains the rings embedded therein with projections of rubber passing both through the perforations and into the grooves, and the cement bonds the rubber to the metallic parts.

The rubber tubing is made of a composition suitable to withstand the vibration and .Xposure to water to which it is subjected. Such a composition can consist of the following ingredients:

Parts by wright Rubber 100 Zinc oxide 2 Lamp black 35 Dibenzylamine 11/2 Sulphur 11/2 cent the shaft can be made of hard rubberl composition. Vulcanization unites -the plies into a unitary sleeve of rubber composition. In some cases it may be advantageous to roughen, plate, or otherwise treat the shaft to obtain a satisfactory foundation for the rubber composition.

A modified form of band is shown in Figs. 7, 8 and 9 in which a band 36 is provided with closely spaced transversely extending slots 37. This form of band can be made in long strips and cut to size as needed, and fastening means secured to the ends. The fastening means for the ends of the band consist of separate clips one of which 38 comprises a body portion from which projects a lug 39 bent to engage a slot 37 of the band and thereby hold the clip securely to the band. The opposite end of a clip 38 is provided with two projecting arms 40, the ends of which are bent about themselves to form locking lugs 41. rlhe other clip 42 is provided with a bent lugv43 for engaging a slot 37 in the band whereby it is secured thereto. From the opposite end of the clip there projects an arm 44 of a size adapted to fit between the arms 40. A bent-over end upon the arm 44 constitutes a locking lug 45. Upon positioning the band 36 with clips 38 and 42 around the rubber tube a Wedge 32 (see Fig. 6) is driven into the slots formed between arms 40 and lugs 41 and arm 44 and lug 45 thereby drawing the parts together.

When the sleeve of rubber composition is to be applied to a member of non-cylindrical shape, such for example as a rod which is rectangular, ovoidal, or otherwise curved or shaped in cross section and which has relatively sharp edges or margins, the edged portion of the rod is preferably provided with a recess wider than the width of the clamping band which is to be used to grip the sleeve to the rod. Such a construction is shown in Figs. 10 to 13 inclusive in which there is shown a strut 50, such as can be used in bracing and supporting a propeller shaft to the side of a ship. The strut terminates in an enlarged portion at one end which is so shaped as to form a retaining hub 51 for the propeller shaft. The opposite end of the strut is enlarged and suitably flanged so that a water tight connection can be formed with the plating 52 of the ship. The strut is generally oval in shape as can be seen in Fig. 11, being given a stream line contour which is gradually enlargedtoward one side and tapers toward a relatively sharp edge at-the opposite side. The ends of the strut adjacent the hub 51 and the plating 52 are enlarged gradually, as can be seen fromV an inspection of Fig. l0. The sleeve of rubber composition is preferably applied over the entire surface which is exposed to electrolytic action. Before applying the sleeve, the edged side of the strut is provided with a plurality of spaced recesses indicated as 53.

The base of each recess extends generally parallel with the surface of the opposite side of the strut. The recesses at the ends of the strut, which recesses are positioned in the gradually enlarged portion of the strut, are made sufficiently wide to receive two or more clamping bands in side by side relation and the base of these recesses is made generally parallel with the first mentioned recesses. The thickened side of the strut can also be recessed at the enlarged tapered end of the strut, as shown at 54, and the base of this recess is formed approximately parallel with the general extent of the strut. The recesses are made suficiently deep in the strut and are given a contour such that when the clamping bands are positioned in the recesses and are drawn tightly around the strut, the tendency of the bands to cut into the sleeve of rubber composition due to the edged and tapered shape of the strut, is eliminated.

ln building up the sleeve, the surface of the strut is preferably cleaned in any way which may be desirable and one or more coatings 55 of rubber cement are preferably applied thereto. A tube 56 of rubber composi tion is formed around the strut and is rolled and stitched into intimate contact with the recessed and cemented strut. 'Clamping bands 57, either perforated or unperforated, are positioned around the tube 56 passing through the recesses 53 and 54 and are drawn together sufficiently tightly by means of the wedge 58 to cause flow of the rubber composition into the perforations of the clamping band. The small end of the wedge is then bent back over the band to lock the connection. The recesses 53 and 54 are now filled in with a body 59 of rubber composition forming a continuous unrecessed coating of rubber composition over the strut. A second tube 60 of rubber composition is then assembled around the strut and is rolled and stitched into place. Vulcanization is now effected under such conditions as are required for the particular rubberV composition used forming a solid sleeve 61 of rubber composition intimately united to the strut and carrying a plurality of clamping bands embedded therein.

While the invention has been described with particular reference to its application to propeller shaft assembly members such as shafts or struts, it is obvious that it can be applied to any type of rod or pipe which is to be subjected to electrolytic or other destructive or corrosive action. A waterproof insulating sleeve with its connecting means such as has been described would be of special advantage, if suitably protected, when applied to a pump rod. In place of a metal band for holding the sleeve in place there can be substituted a band made of any material which will grip the sleeve to a'shaft. Unperforated bands can be used if desired as well as bands o f varying degrees of'width.

By the apparatus just described there has been formed a member which Will have a prolonged life When surrounded by Water. The rubber sleeves or coatings completely surround. the propeller shaft assembly mem- -bers and prevent any access of Water thereto, thereby obviating any electrolytic action. However, due to Whipping of the propeller i shaft, expansion and contraction, and other Cil causes, the ends of the rubber sleeve are liable to become loosened, thereby allowing access of Water to the shaft at the very points Where electrolytic action is most severe, that is, Where the ends of the bronze bearing sleeves 12 meet the steel shaft. By the connection herein disclosed, a permanent and Water tie-ht connection for the rubber sleeve is provided at these points, and as the reinforcing bands used are completely emb-edded in the rubber composition, they are not subject to deterioration such as would occur if they Were on the exterior of the sleeve and in contact with Water.

It is to be understood that the invention is not limited to the particular method of vulcanization set forth. The use of a rubber composition vulcanizable through the agency of carbon disulphide has been found satisfactory, but it is evident that the composition and the means for vulcanizin the same may be considerably varied Without depa` ting from thx spirit of the invention as defined in the appended claims.

Having thus described my invention, what l claim and desire to protect by Letters Patent is:

l. As an article of manufacture, a propeller shaft assembly member, a coating of rubber composition carried by the member, and a clamping band embedded in the coating and encircling the member, said band being provided with means adapted to tighten it around said member.

As an article of manufacture, a propeller shaft assembly member provided with a recess, a coating of rubber composition carried by the member, a rib of rubber composition integral with the coating projecting into the recess, and a clamping band embedded in the coating und encircling the member.

3. As an article of manufacture, a pr peller shaft assembly member provided With a recess, a sleeve of rubber composition encircling` the member. a rib of rubber composition integral With the sleeve projecting into the recess, and a clamping band embedded in the sleeve opposite the recess.

4. As an article of manufacture, a member provided with an annular recess, a sleeve of rubber composition encircling the member, an annular rib of rubber composition carried by the sleeve and projecting into the recess, a perforated clamping band embedded in the sleeve, and ribs of rubber composition inteeveaeos gral with the sleeve extending into the perforations of the band.

5. As an article of manufacture, a member provided with a recess in its surface, a sleeve of rubber composition encircling the member, a rib carried by the sleeve and engaging the recess, a perforated clamping band embedded in and gripping the sleeve, and projections of rubber composition integral with the sleeve extending into the perferations.

6. As an article of manufacture, a propeller shaft assembly member, a sleeve of rubber composition encircling the member, and a plurality of clamping bands embedded in the sleeve at varying radial positions.

7. As an article of manufacture, a member, a sleeve of rubber composition encircling the member, a plurality of perforated bands embedded in the sleeve at varying radial positions, and projections carried by the sleeve extending through the perforations.

8. As an article of manufacture. a pro` peller shaft assembly member provided with an enlarged portion, said enlarged portion being recessed, a sleeve of rubber composition encircling the member and overlapping the enlarged portion, a rib of rubber com position integral with the sleeve and projet-ting into the recess, and a clamping band embedded in and gripping the sleeve opposite the recess.

9. As an article of manufacture, a propeller shaft assembly member having an enlarged portion, a sleeve of rubber composition encircling the member and abutting a portion at least of the enlarged portion, a perforated band gripping the sleeve against the member and projections on the sleeve extending into the perforations.

l0. As an article of manufacture, a member having a recessed enlarged portion, a sleeve of rubber composition encircling the member, a perforated band embedded in and gripping the sleeve opposite the recess, and projections on the sleeve extending into the recess and into the perforations of the band.

ll. As an article of manufacture, a member provided With a plurality of enlarged p rtions in stepped relation, a sleeve of rubber composition encircling the member and at least some of the enlarged portions, and clamping bands gripping the sleeve opposite the enlarged portions.

1Q. As an article of manufacture, a propeller shaft assembly member having an e lged portion, said edged portion being provided With a recess, a coating of rubber composition carried by the member and extending into the recess, and a clamping band gripping the coating to the member, said clamping band passing through t-he recess and embedded in said rubber coating.

13. As an article of manufacture, a propeller shaft assembly member having an edged portionsaid edged portion being proyvided `with a recess, a coating of rubber compositioncarried bythe `member and filling the recess, and a clamping band gripping the coating to the member, said clamping band passing through the recess and embedded in said rubber coating.

14.-. As an article of manufacture, a propeller shaft assembly member having an edged portion, said edged portion being provided With'a recess, a coating of rubber composition carried by the member, and a clamping band embedded in the rubber composition and encircling the member passing through the recess. l

15. As an article of manufacture, a member having a gradually enlarged and edged portion, said edged portion being provided with a recess, a coating of rubber composition carried by the member and a plurality of clamping bands embedded in the rubber composition and encircling the member passing through the recess in side by side relation.

16. As an article of manufacture, a member having an edged portion, said edged por- 'tion being provided with a recess, a coating of rubber composition carried by the member and a plurality of clamping bands gripping the rubber composition and en-n circling the member passing through the recess in side by side relation.

17. As an .article of manufacture, a member having an edged portion, said edged portion being recessed, a coating of rubber composition carried by the member, and a clamping band gripping the coating to saidmember, said clamping band passing through the recess and embedded in the coating.

18. A propeller shaft assembly member having a gradually enlarged edged portion, said enlarged edged portion being recessed, a coating of rubber composition carried by the member, and a clamping band embedded in the coating and passing through the recess.

19. A propeller shaft assembly member having a gradually enlarged portion, said enlarged portion being provided With a re cess the base of Which extends parallel With the extent of the member, a coating of rub ber composition carried by the member, and a clamping band embedded in the coating and passing through the recess.

20. The method of protecting from electron lytic action a plurality of adjoining members composed of dissimilar metals, which consists in covering the members with a sleeve of rubber composition having incorporated bands adapted to clamp the sleeve around the members.

21. The method of protecting Va member exposed to electrolytic action which com prises forming a recess in the member, dis posing a sleeve of rubber composition around the member, clamping the sleeve opposite the recess with a band with sufficient pressure to cause a portion of the sleeve to be projected into the recess, encasing the band with a second sleeve of rubber composition, and vulcanizing.

22. The method of protecting a member lforming a recess in the member, applying rubber cement to the member, disposing a sleeve of rubber composition around the member, clamping the sleeve oppositeV the recess With a perforated band With sufficient pressure to cause a portion of the sleeve to project into the recess and perforations, encasing the band with a second sleeve of rubber composition and vulcanizing.

24. The method of protecting from electrolytic action a plurality of adjoining members composed of dissimilar metals, which comprises applying rubber cement to the members, forming a sleeve of rubber composition around the members, clamping the sleeve with a band around each member, encasing the bands with rubber composition, and vulcanizing. j

25. A method of securing a sleeve of rubber composition to a member provided with a plurality of progressively enlarged portions Which comprises forming grooves in the enlarged portions, coating the member with rubber cement, applying a sleeve of rubber composition to -the cemented member in abutting relation to the end of one of the enlarged portions, clamping the sleeveivith a band, placing a sleeve of rubber composition over 'the lirst mentioned sleeve and extending upon the adjoining enlarged portion, clamping the second sleeve With a band to the last named enlarged portion, placing a sleeve of rubber composition over the second mentioned band, and vulcanizing.

26. A method of securing a sleeve of-rubber composition to a member provided With a plurality of progressively enlarged portions vvhich comprises coating the member With rubber cement, disposing a sleeve lof rubber composition of the approximate thickness of one of the enlarged portions upon the cemented member in abuttingrelation to one of the enlarged portions, clamping the sleeve to the member with a band, encasing the sleeve With a second sleeve .of rubber composition, the second sleeve overlying the next adjoining enlarged portion, clamping the Sleeve With a band opposite the enlarged portion, encasing the last mentioned band with a sleeve of rubber composition, and vulcanizing.

27. The combination with a propeller shaft assembly including bearing sleeves mounted upon the shaft, of a covering of rubber composition adhesively connected to the shaft and the sleeves and adapted to prevent communication of water between said shaft and the sleeves, and retaining bands embedded in the rubber composition.

28. The combination with a propeller shaft assembly including bearing sleeves mounted upon the shaft, of a covering of rubber composition adhesively connected to the shaft and the sleeves and adapted to prevent communication of water between said shaft and the sleeves, said bearing sleeves being provided with annular reduced portions in the form of steps over which the ends of the rubber covering extend, said steps having de-- pressions in which the covering is anchored.

29. The combination with a propeller shaft assembly including bearing sleeves mounted upon the shaft, of a covering of rubber composition adhesively connected to the shaft and the sleeves and adapted to prevent communication of water between said shaft and the sleeves, said bearing members being provided with annular reduced portions in the form of steps over which the ends of the rubber covering extend, and retaining bands embedded in said rubber covering around said steps.

30. The combination of a propeller shaft assembly including bearing sleeves mounted upon the shaft, a covering of rubber composition adhesively connected to the shaft and the sleeves and adapted to prevent communication of water between said shaft and the sleeves, said bearing members being provided with annular reduced portions in the form of steps over which the ends of the rubber covering extend, said steps being provided with annular grooves, and retaining bands embedded in said rubber composition over said grooves.

31. A propeller shaft assembly including a shaft and bearing member secured thereto, said bearing members being reduced to form a plurality of annular steps of successively decreasing diameters, and a plurality of layers of rubber composition placed one upon another around said shaft and having the ends thereof respectively covering the successive steps of the bearing members, the rubber composition being adhesively united to the shaft and the bearing members and vulcanized together to form a unit.

32. The combination with a propeller shaft assembly including a bearing sleeve mounted upon the shaft-of a covering of rubber composition surrounding the shaft and overlapping the bearing sleeve, said covering being adhesively united to the shaft and the bearing sleeve, and a clamping element for holding the overlapping portion of said covering in intimate contact with the bearing sleeve.

33. The combination with a propeller shaft assembly including a bearing sleeve provided with an annular groove, of a covering of rubber composition surrounding the shaft and overlapping the bearing sleeve and provided with a bead fitting into said groove, said covering being adhesively united to the shaft and the bearing sleeve, and retaining bands associated with said covering and forcing the bead into the annular groove.

34. The method of protecting from electrolytic action a propeller shaft having a bearing member thereon, which consists in covering the shaft with a sleeve of rubber composition, extending the end of said sleeve over the end of the bearing member, adhesively connecting said sleeve to the shaft and the bearing member, reinforcing said sleeve With retaining bands adapted to encircle the shaft and the bearing member, and vulcanizing the whole to form a unit.

35. In combination, a shaft, a bearing sleeve, and a waterproof covering over the shaft and the bearing sleeve, said sleeve having an annular groove in which the waterproof covering is anchored.

3G. In combination, a shaft, a bearing sleeve, and a waterproof covering over the shaft and the bearing sleeve, said sleeve having an annular groove, and bands arranged to hold the covering anchored in the groove.

Signed at New York, county and State of New Yori, this 28th day of September, 1927.

HERBERT CHRISTOPHERSEN.

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