US2354445A - Resilient bushing for outboard motor mountings - Google Patents

Description

July 25, 1944. w. J. GRUBBSv 2,354,445

RESILIENT BUSHING FOR OUTBOARD MOTOR MOUNTING l Filed sepi. 1o, 1942 INVENTR* WILLIAM d. GRus ATTORN EYS Pianta r.hay 2s, 1944 nasiLmN'r nusnmarolt oU'rBoAa Mo'roa MoUNTmGs William-J. Grubbs, Akron, ohiassignor to 'rile Firestone Tire & Rubber Company; Akron. Ohio,'a corporation 'of Ohio v Application septemberllo, 1942, serial-No.45'7gs9a 3 claims.; (crus-gt4)` w traitor holding hisy handon thev tiller. This isV true, as for example; in the case of a man trollingj when his Acourse lay off a curved shore line or C This invention relatesto bushings, .and more .particularly it relates to a bushingin which a driveshaft housing of an outboard motor revolves.

An object of the invention is to provide a bushingl for .an outboard motor Ldrlveshaft housing that will permit easymanual turning of the housing while providing enough friction betweenthe bushing and the, housing so that thesteering" handle or tiller of an outboard motor may be set at a selected position andit will remain in that position until purposely moved by the operator ofthe boat. ,v l

Another objectof the invention is toprovide a bushing that is adapted to intercept oil running down the outsidey driveshaft housing andito rethe bushing from which openings the oil-grad- I 16 ceivesuch oil in openings formed in the walls of ually emerges and distributes itself over the bushingcontact surface.' j A Y A further object of the invention' is to provide a bushing having attached toits inner surface a fabric so treated that it will Ihave a high static and a low dynamic friction. f

Afstill furtherA object of. the invention is to provide a bushing that `will functionl asa vibration dampenei' between an outboard "motor supporting means and aiboat uponwhich the said motor is mounted.

Yet` another obiectofthe invention is to provide a bushing for themounting 4bracket; ofV an outboard motor that will not injure the 'drive shaft housing which is mounted therein. The driveshafthousingsrof outboard motors are generally` madefof anon-ferrous metal'such u aluminum `or bronze; otherwise. the housing would rusty asl it is exposed to water. The aty taching brackets are ordinarily made of cast iron, ,A

such brackets having two-arms which terminate in split yokes. These yokes have machined bearing surfaces which when the yokes are assembled provide bearings inwhich thedriveshaft housingl is revolvablyheld. The vibrations of outboard motors are severe and in service the softj:metal"`- of the housing is frequently broken yor worn through` bythe hardermetalof thel attaching bracket. Not only do the motor vibrations `cause the harder metal tocut through the softer but the turning of the `housing in its bearing, which occurs insteering 'a boat, ralso causes weary between the bracket and the housing. These are serious faults of prior art..

In operating a boat driven by an outboard mon tor it is often desirable to be able to set the tiller to steer the boat in a circular course and to have the tille'x` remain in that position without the oparound submerged rocks. In such case a mans handslare ordinarily occupiednwith his fishing tackle. However; heretofore tillers would-not hold such set .positions unless the-'bearings were so tight on the" driveshaft 'housing' that the tiller' was too hard tofturn to besatisfactory and-also would cause the housin'g'to be injured by itstightl fit in its metal bearing.

`The `abovefand other objectsaand advantages of this invention will be more fully understood by referring to the following description panying drawing in which:

Fig. 1 is azperspecti've view of an outboard mol-" y tor mounting embodying this invention and show-A ing such motor in operative position attached'to a boat;

Fig. 2-is a sectional view taken on line'fZ-'Ir of Fig. 3; and

-Fig...3 is a cross-sectionai view taken on une?` o 3 3 of Fig. 1.

As illustrated in' `1 of lthe drawing 'the mounting' kcomprises 'an outboard motor` i0,"a

tiller 9, a yfuel tank ii, aj starter wheel i2; exhaust.

' pipe la. exhaust bracket iaaydrivesin'ntt i4, irive-`A shaft housing ll, gear transmission I8, propeller I1, mounting bracket i8, and boat bracket-il.

-The motor mounting bracket il has an upper and a lower' arm terminating-in one portion of respective split yokes 30 and 3l.- The portion a necessary tojcomplete the 'yoke 30 lis attached thereto-.by bolts I2 vand nuts 33. 1n similar fash` ion the yoke Il is completed by portion 3io iltfH tached thereto by bolts'u and'nuts ll. Since. the bushings in the yokes are identical,r theinvention will be explained in connection with the bushing mounted in the upperyoke 30.' As willy be understood by those familiar with the art, out.

board motors are'usually mounted on boat brackets provided tobe attached to the rear of aboat. The rboatbracket and the motor mounting-bracket are also adapted'fo'r pivotal.` attachment as shown at 36 in Fig. 1. indicated vabove the l motor mountinggbracket is usually castfof iron and it `has'the ends of its'arms machined to form' l a bearing in which the drive shaft housing is *f mounted. The top of .the bracket is assembly contacts the bottom of `the motor rin .order to support the `Weightof the motor andits assembly,

thus avoiding the necessity of clamping the h'ous-r ing tightly in its bearings. The' lower. end of the` motor mounting bracket is similarly fastened and engages the housing i'in'order to stabilize it.

and accom- As will be seen by reference to Figs. 2 and 3 a bushing Il is mounted in the split yoke 3l. Bald bushing is molded in the usual manner of manufacturing mechanical rubber goods; however in molding, a plurality of circumferentially spaced rectangular recesses I2 are formed in the walls 0f the bushing. It is to be noted that these recesses do not extend entirely through'the bushing but terminate at an inside layer of fabric Il. It is also to be noted that the fabric 4i is turned outwardly over the edges of the bushing and accordingly much of the weight of the motor rests on the fabric. It is to be understood, however, that the inner layer of fabric may end flush with the end of the bushing. It will be seen; of course, that when the bushing 4d is in its mounted lposition the recess I2 is converted into a compartment between the fabric 4l and the metal in said split yoke. It will also be seen that Ytherinside face of the split yoke 30 has an inwardly extending projected portion adapted to enter for a short distance diametricallyopposite recesses 42. These portions II act to prevent the bushing from turning with said housing. As `this bushing is exposed to oil, as willbe explained hereinafter, it is formed oi.' an. oilfresistant rub-v ber-like material, such as for example, but without limitation, a copolymer of butadiene and acrylanitrile sold under the name of Buna N, or a polymer of 2-chlorobutadiene sold under theV name of neoprene. However, if a material such as neoprene provided the Adirect frictional contact surface against the driveshaft housing the bushingv would be worn away, alsoit would not provide a satisfactory contact surface. Accordingly this invention provides a contact surface by molding on the inside surface of the bushing said layer of fabric as stated above. Y v

Aiaterally and upwardly extending circumferentialv rib 50 is projected from the outside surface of the 'members of the split yoke.

This rib forms a groove 5L between it and thev members of said yoke. The grooves ,5i` have closed ends (not shown) and openings from the groove 5| "in the form` of drilled holes 52 `extend through the walls of the said yoke opening on assaut Afterfsaid bushing Il has been molded and vulcanized it is dipped into a solution of paramn and oil and allowed to remain in the solution long enough for the fabric Il to become impregnated with theA paraffin. Of course, the entire bushing becomes coated and it has been found I that paranln provides avery good protection for the bushing during storage and thereafter. 'I'he impregnation of the fabric with the parailin is an important feature of the invention. Applicant has found that by this means he is'able to `provide a -high static friction between the driveshaft housing and the fabric. Therefore, when the split yoke is tightened only lightly against the housingr considerable resistance against rotary movement of the housing in its bearing is n set up. It is to be understood that driveshaft the inside into said rectangular recesses 42 in the evaporates butthe oil will run down the exhaust pipe and the drivesha'ft housing. Oil running` down the yoke will be intercepted in said grooves Il and flow through the holes 52 into the recesses 42 where it is retained until it gradually seeps through the treatedvfabric ll. When an outboard motor is in actual servicethe amount of oil which has4 heretofore been vlost in this way is considerable and it will be seen from the foregoing thatthis inventiondenes means 'for interceptingv and saving the 'oil that otherwise would run down said housing and be wasted. Also means are described for retaining the excess of said oil within the openings of said bushings where it is stored but exposed to the fabric wherehousing il is rotatedby the tiller 'l in the manner common in the art. Consequently if the operator of a boat sets the tiller in a position to cause the boat to be driven in a chosen arc, it will not bel necessary for him toV keep his hand on the tiller as it will remain in that position until manually moved. v However, if the tiller is manually moved .thereby breaking the grip or seal of the fabric 4I to said housing then the dynamic friction between the housingfand the fabric is very low and the tiller can be easily shifted from one position to another. f

Outboard motors are often mounted upon rowboats which are not built sturdy enough to withstand the vibrations transmitted to the boat from necessary to retain anoutboard motor in operative position is quite hard asit has no openings into which it may distort; In the present ini' vention cushioning eifectis made'possible by pmviding thesaid rectangular openings into which the bushing can expand when subjected to the terial, willv not crush or wear through 'the housby oil gradually seepsthrou'gh the fabric and y keeps the frictional contact surface between the housing and the bushings lubricated. Of course,

if there was not' enough oil supplied to the bushing due to the spilling of the gasoline `then the required amount of oil for lubrication could be fed directly to the bushing from an voil can.

ing wall. The elastic quality of the bushing makes it possible to tighten it to cause only slight compression of its walls against the said driveshaft housing in which condition it will maintain contact with said. housing over a long period of service during which time the bushingl exerts a continuous and gentle' pressure on the housing, holding it in a predetermined operative position without yrattle or chatter between the housing and the bushing bearing.

While only one embodiment of the invention musing being composed o; an outer im: or ouresisting rubber-like material, said material bea ing of substantial thickness, and having relatively large openings formed through it at circumferentially spaced intervals, said bushing havingv an inner layer of fabric, said fabric being exposed to .said openings'in said outer layer, said fabric being saturated with a solution of oil and paraffin, and a metal split yoke in .which the bushing is mounted to form a bearing for a driveshaft housing of said motor, said yoke having a laterally and upwardly extending circumferenf ing openings formed therethrough at circula-k* ferentially spaced intervals, said' bushing having an inner layer of fabric, said fabric covering the tial rib which defines a groove between said yoke n and said rib, said yoke having inlet holes extend-V ing through the wall of the yoke from said groove to said openings in the bushing, whereby spilled oil running downwardly over said yokeis caught in the groove. and delivered through the inlet holes to the openings in the bushing, thereby pro- A viding a reserve supply of oil in contact with Vsaid inner layer of fabric through which it is gradually absorbed and of said bearing. a

2. The combination with an outboard motor mounting of a hollow cylindrical bushing, said delivered to the surface bushing being composed of an outer layer of oilresisting rubber-like material, said outer layer having relatively large radially inwardly extendinner ends of said openings, means for supplying a lubricant to said openings while said bushing Y, is in operative position, thereby providing a res-r ervoir communicating with said fabric through.

` a laterally and upwardly extending circumferenf [tial rib which defines a groove between said'yoke and said rib, said yoke having inlet holes extending through the wall'of the yoke from said groove to said openings in said bushing, whereby spilled oil running downwardly over said yokeis caught'in the groove and delivered rthrough the inlet holes'tothe openings in the'bushing, thereby providing a reserve supply of oil to the surface of said bearing. Y Y

a WILLIAM J. GRUBBS.v

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