US2348945A - Protected internal bearing for concrete mixers - Google Patents

Description

y 1944- J. R. WILLIAMS 2,348,945

PROTECTED INTERNAL.BEARING' FOR CONCRETE MIXERS Filed Jan. 9, 1942 2 Sheets-Sheet l May 16, 1944- J. R. WILLIAMS PROTECTED INTERNAL BEARING FOR CONCRETE MIXERS Filed Jan. 9, 1942 2 Sheets-Sheet 2 IN VEN TOR.

IIIIIIII III I ATTORNEY Patented May 16, 1944 PROTECTED INTERNAL BEARING FOR CONCRETE MIXERS Joseph R. Williams, North Plainfield, N. J., assignor to Ransome Qoncrete Machinery Company, Plainfield, N. J., a corporation of New Jersey Application January 9, 1942, Serial No. 426,117 3 Claims. (01. 259-175) .The improvements relate to bearings and their housings, and more particularly to bearings located and operating in the presence of a liquid or other penetrating and injurious material or elements. j

The present application of the improvements is to the bearings of a shaft extending from outside the charging end of a two-compartment rotary drum concrete mixer along the axis of the drum for the purpose of operating, by rotating through an arc of a circle to transferring and non-transferring positions, a transfer chute for the concrete aggregates being mixed in thedrum compartments. It is necessary that such a shaft shall'be supported in position by a support between the'charging head of the drum and the chute at its inner end, so that 'it will withstand the impact of the 'heavy concrete aggregates charged into the drum by the usual'charging chute, through which the shaft extends, I and falling from the upper part of the drum during the mixing operation, as wellas the impact 'and Weight of such aggregates on thertransfer chute, and the other' shocks, vibrations and strains incident to the operation of the mixer. For this purpose a spider is usually provided having its extremitie's fixed to the shell of'the drum and having a bearingfor the shaft at its middle, so that both the' shaft and the chute are supported and maintained in proper position thereby, the drum permitted to rotate about the shaft and the shaft to rotate in the said bearing to operate the chute.

v I To provide proper lubrication for such a bearing and to protect it against thepenetration and injurious efiect of the wetconcrete' constantly thrown i tliereon during the. mixing operation is the primary object of the present improvements. Other objects and other uses will be apparent to those skilled in'fthej a'rt ,fromthe' following asscri'pti'onL.

The improvements are illustrated in. the accompanying drawings, referred; to herein, which show anexemplar-y embodiment.

In the said drawings, Fig.1 is a yertical medial section of the charging end'jand middle portion of, aitwo-co'mpartmeii rotary concrete mixer with, the parts involved, in, the present improvementsshown diagrammatically;

Fig. 2 is a similar section of ,th bearing and its lubricating andprotecting me s embodying eim rqt m sig J i P 1 --The transfer chuteoperatingshaft'l is mount ed in the spiderfi' fixedto the innershell of the drum, by'the bearing 3 and'on'its-inner end has the rotary transfer chute 4 mounted by means of a collar 5 receiving the end of the shaft, which is keyed or otherwise fixedthereto. The shaft extends through the feed chute 6 to a point outside the mixing drum and chute where it is provided with a connection I for oscillation by suitable power means and resulting rotation of the transfer chute through an arc of degrees or more to transferring and non-transferring positions. It will be understood that the inner shell of the drum is provided with concrete mixing blades of any desired form for lifting, dumping and otherwise agitating the wet concrete in the drum, and usually consisting of stone, sand, cement and water. Such blades are illustrated in the copending application of John P. Faber, filed October 12, 1938, Serial No. 234,530, and in that application are also shown certain details of the shaft, transfer chute and other parts notfully illustrated herein (see Patent No. 2,282,467

granted May 12, 1942).

The shaft I has a bore 8 therein running from its outer end to a point inside the bearings 9 and connected with the annular gland II] and grease packing chamber II through lateral ducts I2 and I3. A hardened steel collar I I is pressed on the shaft I, so as to be substantially integral therewith, and to cooperate with the roller bearings 9 to provide the bearing proper between the shaft and its mounting in which the former may turn to operate the chute and the latter may rotate with the spider 2 and the mixing drum I5, while the shaft remains stationary.

Collars I6 and I1 are also fixed on the shaft I and between them and the inner housings I8 and I9 are suitable packing rings 20 and 2|. The

outer end of the bore 8 is provided with a fitting of the Alemite type (not shown) to receive the nozzle of a grease gun of the same variety, by which lubricant is forced under pressure in through the bore 8, the ducts I2 and I3 into the channels Ii) and II, the annular channel IIl' receiving its lubricant through between the roller bearings. In this manner, the bearings and the annular grease chamber II are supplied with lubricant from time to'time as required.

At the inner end of the bearing structure and also at the outer end are located grease cups 22 and 23, the latter providing the chamber II and the former a similar chamber 24, which is not in communication with lubricating bore *8 but receives lubricant 'to a certain extent, after being initially'packed, from-the .duct I2 and gland I I] through the packing 20 and the space between the ring 25 and the collar I6. These cups are formed in two sections united by projecting lugs 26 through which clamping bolts 21 are passed. The ring 25 is united with the outer housing cylinder 28 by means of screw bolts 29 passed through the former through upward extensions iii of the inner housing members l8, which have each a small spacing ring l8, and in this manner the bearing is compleely housed and its parts maintained in proper position and relation.

The shaft i8 is provided at both ends of the bearing and lubricating structure with a sleeve 39 of heavy closely Woven duck canvas, or similar material having the properties of such canvas, and the inside of each grease packing cup is provided with a lining 3! of similar material. The object and function of this canvas is to protect and guard the bearing in a peculiar manner. The aggregates of concrete when mixed or partly mixed contain a liquid composed of water, Portland cement and sand, which is commonly called soup, and this liquid has a penetrating quality comparable with that of water, particularly the portion of it which consists of water and cement, the cement being pulverent material of a gritty, abrasive character. It also has the effect of causing deterioration or hardening of viscous substances, such as ordinary lubricating oils and greases which it may penetrate or with which it may become mixed. The cement in a mixer is in a nascent state since it has been hydrated and has started to set or transform from a light powder to binding cement. It has therefore been found that the liquid of the concret mixture will penetrate very small interstices, such as exist in the bushings of bearings and the joints between their casings and rotative or non-rotativ parts. This penetration destroys the lubricating effect of oils, greases or other lubricants and causes abrasion and quick destruction of the effectiveness of such parts, through quick Wear or heating due to the friction. In bearings of the kind here involved this undue wear and destruction will occur even when the bearings are cleaned and packed with fresh lubricant daily, and even when the bearings are new and unworn, and the necessit for such frequent packing. and lubrication is a source of great trouble and expense, since the location of the bearing requires that a man with tools shall creep inside the drum and attend to it each day during operation and even oftene'r, as has been found necessary to maintain the life of the bearing for even a short period.

Various means have been employed to overcome this penetration of the liquid and it injury to the parts, but heretofore Without success. Thus, rubber, leather'and other packings, both under compression and without compression, have been used ine'ifectively, and the present improvements involving the use of canvas or similar fabric supplied from inside the housing with a body of lubricant which will penetrate and saturate it by capillary action was discovered after many trials and failures.

In practicing the invention, themain bearing is first assembled in the manner indicated. The two end grease boxes or cups 22 and 23 are then filled with a waterproof grease packing 32 such as is used on pumps, placed in position on the housing and clamped thereon by tightening the bolts 21, the said cups being first provided with the canvas linings 3i and the shaft I being provided with the-canvas sleeves 33. The bore of the shaft I and the glands in communication therewith are then filled with aiiuent lubricant 7d under pressure by means of a pump connected at its outer end. This completes the assembly and lubrication of the bearing and its protective housing and also exerts a certain pressure on the packing in the cups as well as causing some of the liquid lubricant to penetrate along the shaft and enter the canvas packing sleeves. cant will also impregnate the linings 3| at this time, and this lubricant entering the canvas packing sleeves and lining will pass by capillary action to the portion of the canvas which'extends beyond the joint in which it is held. The machine should then be rotated for a short time in order to give the lubricant an opportunit to saturate the canvas packing both inside and outside the housing.

When the concrete dry aggregates and water are then deposited in the mixing drum, through the chute 6, and the drum rotated, the shaft l'remaining stationary, the liquid in the mixture will be constantly raised with the solid aggregates and cascaded tothe bottom of the drum, pouring over the bearing in its fall and thoroughly showering the joints of the housing and the canvas packing. The lubricant, however, will prevent this liquid from penetrating the canvas packing or passing between it and the surrounding metal to the interior, and as this lubricant is washed off the outer surfaces of the canvas by the liquid, lubricant capillaried through the canvas to the exterior will take its place, so that an effective water-tight seal will be maintained.

It will thus be seen that the packing of the joints of the housing is maintained by constant saturation of the canvas packing within, in'and beyond the joint and that this is made possible by the capillarity of the fabric.

The canvas sleeves are, not substantially com-- pressed when the cups are clamped on the housing and they are not tightly'clamped in the open ings formed at the axes of the cups; They are squeezed however to some extent so that they will hold their positions but not to an extent sufficient to destroy their capillarity which would cause them to lose their lubricant on the outside, absorb the liquid, be hardened by it and rot out. They may however be held in position by other suitable means. They also maintain a certain degree of elasticity for a relatively long period and will remain intact and function as herein described for several months in constant use.

The shaft bearing is fixed to the spider by means of flanges 33 extending from its housing bolted, welded or otherwise secured to the hat inner end 2 of the spider legs, or in'anyother suitable manner. j h I What variations o1. equivalents of thefc'anvas maybe employed and 'to what extent; capillary action is essential and has not been determined. It is apparent, however, that a fabric of fibrous material having capillarity and also a certain degree of elasticity must be used to secure the desired result. The'bore of the shaft .mayalso be extended to a point opposite the insidei'jcup and be provided withia radial duct 'forldirect communication therewith, although this has not been found necessary, and various other modifications of the exemplary embodiment shown may be made without departing'from the scope of the invention.

' What I claim is:

1. In a device of the character indicated, a rotary drum, means for mixing, wet concrete asgregates therein,- a shaft',extending into said drum, bearings between saiddrum and shaft Lubriwithin the mixing zone of said drum, means fixed within the drum for supporting said bearings, a housing for saidbearings and means between said housing and shaft and extending along the latter and from within to beyond the former for maintaining a seal against the wet aggregates and protecting the bearings against them, 'comprising a fabric of fibrous capillary material and a body of lubricant inside said housing in contact with said material,

2. In a device of the character indicated, a rotary drum, means for mixing wet concrete aggregates therein, a shaft extending into said drum, bearings between said drum and shaft within the mixing zone of said drum, means fixed within the drum, for supporting said bearings, a housing for said bearings and means between said housing and shaft and extending along the latter and from within to beyond the former for maintaining a seal against the wet aggregates and protecting the bearings against them, comprising a fabric of fibrous capillary material in the form of a sleeve on the shaft and a body of lubricant inside said housing in contact with said material and extending through such material by capillary action.

3. In a device of the character indicated, a rotary drum, means for mixing wet concrete aggregates therein, a shaft extending into said drum, bearings between said drum and shaft within the mixing zone of said drum, means fixed within the drum for supporting said bearings, a housing for said bearings and means between said housing and shaft for maintaining a seal against the wet aggregates and protecting the bearings against them, comprising a fabric of fibrous capillary material and a body of lubricant inside said housing in contact with said material, said housing being jointed and a similar means for maintaining a seal between the joints of said housing.

JOSEPH R. WILLIAMS.

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