US3026733A - Mechanical vibrator - Google Patents

Description

March 27, 1962 c. F. CARLSON 3,026,733

MECHANICAL VIBRATOR Filed Oct. 2, 1958 ,Ziz (Jen/56v gZare/zz C6 FUaFZSm ite States Patent 3,026,733 MEQHANICAL VHBRATOR Clarence F. (Iarlson, 751 Spring St, Aurora, Ill. Filed Get. 2, 1953, fier. No. 764-352 4 illaims. (Cl. 74-87) This application is filed as a continuation-in-part of my copending application, Serial No. 699,236, filed November 27, 1957, and now abandoned, the disclosure of which is hereby specifically incorporated by reference,

This invention relates to a mechanical vibrator where in a vibratile hollow body receives a rotatably mounted drive shaft for one or more mass elements such as ball or roller type bearings which are confined loose within said body for movement about the axis of the shaft in unbalanced distribution thereabout.

Such vibrators are useful in a Wide variety of applications; for example, they may be arranged for contact with freshly poured concrete to assist in the operation of puddling the concrete; or they may be embodied as the vibration source for a massaging device; or they may be arranged to vibrate a screen-like member such as is used in the grading or sorting of sand, gravel, or coal. Applications for such vibrators are quite numerous, and the above examples are not intended as limitations to the field of use of the invention.

The present invention is particularly concerned with vibrators of the class that utilizes a direct mechanical drive between the source of power and the vibrator itself, as distinguished from the class of vibrators wherein the vibrator is actuated directly by pneumatic power. in the case of the direct mechanical-drive type vibrators of the prior art, the bearings for the rotatable drive shaft are subjected to intense wear, which greatly limits their useful life.

It is the principal object of the present invention to provide a vibrator arrangement that is capable of withstanding intense usage over extended periods of time without failure or impairment; that may be oriented to any desired position of use; that allows for ready adjustment of the frequency and amplitude of the vibrations produced; that is substantially free of frictional drag in the driving system; and that eliminates the need of close manufacturing tolerances and hence is easier and more economical to construct.

Another object is to provide a vibrator of the above type wherein the vibration-producing mass is arranged loose within a vibratile barrel.

It is a further and specific object of this invention to provide a vibrator of the above-mentioned type with a direct mechanical drive.

Other objects and advantages will become apparent during the course of the following description.

In the accompanying drawings forming a part of this specification and in which like numerals are employed to designate like parts throughout the same:

FIG. 1 is a longitudinal sectional view disclosing the vibrator of this invention;

FIG. 2 is a side-sectional view taken along the line 2-2 of (FIG. 1; and

FIGS. 3 and 4 are side-sectional views generally corresponding to the view of FIG. 2 and illustrating two further embodiments of a vibrator constructed in accordance with the present invention.

Referring now to the drawings, the invention is dis closed in the form of a mechanical-drive type vibrator wherein the motion of a rotatable shaft is translated into vibrations of a vibratile hollow body member 11 through the medium of a mass 25 disposed loosely within the hollow member.

The driving power for the shaft of the disclosed ar- 3,fi2fi,733 Patented Mar. 27, 1952 rangement may either be supplied from an electric motor or pneumatic motor or any other suitable source of rotary power, and the connection between the driving motor and the driven shaft may either be in the form of a rigid extension of the drive shaft or in the form of a flexible coupling shaft.

In applications such as involved in the puddling of concrete wherein the vibrator is in actual contact with the concrete, an outer protective shell may be applied over the vibratile member. If, in such an arrangement, the shaft includes a rigid extension to a driving motor, the protective shell may be extended to encase both the vibrator and the motor. Where a screen-like member such as is used in grading or sorting is to be vibrated, the vibrator may be directly secured thereto, in which case a protective shell may not be required.

The various arrangements for adapting the vibrato of the present invention to the wide variety of potential uses which exist for it will be apparent to those skilled in this art, and the present invention is basically concerned with the construction of the vibrator itself.

In the vibrator construction illustrated in FIGS. 1 and 2 for purposes of disclosure, the drive shaft 10 carries a plurality of fins 13 spaced at equal intervals thereabout to provide a dynamically balanced shaft. The vibratile member 11 is in the form of a cylinder or barrel that defines a lengthwise extending chamber and that is formed at its opposite ends with annular recesses to present oppositely, outwardly facing, annular abutment shoulders 113; the mass 25 is in the form of a roller type bearing for minimizing internal friction and is confined between the barrel 11 and the shaft 10 in unbalanced distribution about the axis of rotation of the shaft and disposed throughout the length of the chamber defined thereby. Preferably the fins 13 extend to a point closely adjacent the cylindrical internal surface defined by the barrel ill to form the chamber into a plurality of cOrnpartments 14- that extend the length of the chamber, with the ends of such compartments being sealed by end plates 15 insertable in the recesses at the ends of the barrel for abutting engagement with the annular shoulders MS. The end plates are secured in their illustrated position by snap rings, as indicated at 16, or in any other desired manner. The end plates are formed with aligned openings 17 through which the ends of the shaft 10 extend, and these plates are preferably arranged to provide annular pockets flanking the openings 17 for receiving anti-friction facilities which, as shown at 18, may be in the form of ball-bearing assemblies. The ball-bearing assemblies 18 are isolated from the cylindrical pocket defined by the annular wall portions 19 that flank the openings 17, and they may be held in place by a snap-ring arrangement 2% or in any other suitable manner.

Therefore, the shaft 10 is supported at its opposite ends in the ball-bearing assemblies 18, and it is in perfect dynamic balance so that, upon rotation thereof, no appreciable eccentric loading of the ball-bearing assemblies occurs. The bearings for the shaft, therefore, will have a long, effective life.

The vibrations of the vibratile barrel 11 are produced by the action of the mass 25, which is driven circumferentially about the axis of the shaft by the rotating fins 13. The frequency of the vibrations produced in the barrel 11 is primarily dependent upon the speed of rotation of the shaft 10, while the magnitude of the vibrations is dependent upon the weight and distribution arrangement of the mass within the barrel.

One of the important features of the invention resides in the fact that the mass, the motion of which sets up the vibrations in the barrel, derives its momentum from the drive shaft 10, but since it is loose with respect to the drive shaft, imparts no eccentric loading upon the shaft, and, hence, no eccentric loading upon the shaft bearings 18. These shaft bearings have been the usual point of failure in prior art vibrators employing a mechanical drive.

While three fins 13 are shown in the arrangement of FIGS. 1 and 2, it should be apparent that any number of fins may be employed, though in each case it is desirable to provide for dynamic balancing of the shaft.

Another feature of the vibrator construction resides in its economy of manufacture. The clearance between the fins 13 and the cylindrical internal surface of the barrel 11 is not critical; and it is, in fact, desirable that these parts do not engage in any manner in order, again, to minimize internal friction.

For purposes of reducing internal friction, a suitable lubricant is provided in the barrel 11. Preferably the shaft is provided with an oil passage 22 opening through the free end thereof to permit introducing oil after the vibrator is completely assembled. A suitable threaded plug 23 seals the passage 22, the inlet of which is suitably tapped for this purpose.

It will be apparent that the distinctive characteristic of the embodiment of FIGS. 1 and 2 resides in the use of an elongated roller 25 as the mass element. This roller preferably extends substantially the entire length of the barrel chamber with sufficient end clearances being provided for free movement of the roller within the chamber.

It should be understood that one or more rollers suitably distributed in separate compartments may be provided as required, and the rollers may be of a variety of sizes in accordance with the particular vibration characteristic required. The use of elongated rollers has the advantage over the use of ball bearings that the tremendous pressure on the barrel wall is more uniformly distributed along the length of the wall, and this minimizes wear and scoring of the barrel wall.

While roller bearings of uniform cylindrical surface configuration are contemplated within the scope of this invention, the roller element disclosed in the embodiment of FIGS. 1 and 2 is shown formed with a helical screwlike groove 26 to provide a smooth-surfaced, screw-like roller element that exhibits superior performance characteristics in terms of low internal friction resulting from a superior lubricating action and in terms of reduced heat and wear resulting from a more uniform distribution of pressure along the length of the barrel wall. As is apparent in FIG. 1, any longitudinal cross section through the roller is characterized by alternate lands and grooves.

The improved results are attained principally because of the active lubricating action that is developed with the grooved screw-like roller bearing element, the grooves of which continuously and uniformly spread the lubricant on the surface of the barrel wall, as distinguished from a uniform cylindrical roller element which continuously acts to push the lubricant ahead of it. Tests indicate that with the screw-type roller, the internal surface of the barrel wall is actually subjected to a burnishing action rather than a Wearing action.

There are a number of forms which the roller bearing element may take, depending upon the vibration requirement of the various applications that may be made of the vibrator of this invention. As shown in FIG. 3, the roller element 25' may be formed with an off-center bore- 25B to produce an eccentric or pulsating vibration component. Alternatively, as shown in FIG. 4, one roller bearing element may be arranged within another, in which case the outer roller bearing is in the form of a cylindrical tube 27 and the other roller bearing 28 rides within the tube-like element 27 and acts to develop its own vibrational characteristic that is superimposed upon the vibrational characteristic produced by this tube alone. In any of these arrangements the roller bearings may be of a uniform surface configuration though, as explained previously, they preferably are grooved to provide screwlike, fiat-surfaced roller elements. In the FIG. 4 arrangement where one bearing operates within another, the inner bearing may have an eccentric lengthwise bore to provide still an additional vibration component.

It should be understood that the description of the preferred form of the invention is for the purpose of complying with Section 112, Title 35, of the US. Code, and that the claims should be construed as broadly as prior art will permit.

I claim:

1. In a rotatively operated vibration device adapted for attachment to a member to be vibrated, a vibratile hollow body defining a lengthwise extending chamber, lubricant in said chamber, a rotatably mounted shaft extended lengthwise through said body axially of said chamber, and a generally cylindrical roller bearing element confined loose within said chamber to extend substantially the length thereof, said roller bearing element having an eccentric bore extending lengthwise therethrough, with the portion of said shaft within said body being of noncircular cross section for driving said element about the axis of rotation of said shaft by loose fitting abutting contact therewith.

2. The arrangement of claim 1 wherein a second roller bearing element is loose within and extends lengthwise through the bore in the first named roller bearing element.

3. In a rotatively operated vibration device adapted for attachment to a member to be vibrated, a vibratile hollow body member having an internal surface defining a lengthwise extending, generally cylindrical chamber, lubricant in said chamber, a rotatably mounted shaft extending lengthwise through said member axially of said chamber, and a first roller bearing member confined loose within said chamber to extend substantially the length thereof and having a generally cylindrical external surface, said roller bearing member having a bore extending lengthwise therethrough and having a second roller bearing member loose within and extending lengthwise through said bore in said first roller bearing element, with the portion of said shaft within said body member being of non-circular cross section for driving said first roller bearing member about the axis of rotation of said shaft by loose fitting abutting contact therewith such that said first roller bearing member moves along the periphery of said chamber, with the external surface of said first roller bearing member moving in rolling engagement with the internal surface of said body member, one of said surfaces having a longitudinal cross-sectional surface configuration characterized by alternate lands and grooves facilitating continuous uniform spreading of lubricant on both of said surfaces by the rolling action therebetween.

4. In a rotatively operated vibration device adapted for attachment to a member to be vibrated, a vibratile hollow body having a cylindrical internal surface surrounding and defining a lengthwise extending cylindrical chamber, lubricant in said chamber, a rotatively mounted shaft extending lengthwise through said body axially of said chamber, and a first roller bearing element having a continuous helical groove in its external surface confined loose within said chamber and extending lengthwise therein, said roller bearing element having a bore extending lengthwise therethrough and having a second roller hearing element loose within and extending lengthwise through said bore in said first roller bearing element, said second roller bearing element having a continuous helical groove in its external surface, with the portion of said shaft within said body being of non-circular cross section for driving said first roller bearing element about the axis of rotation of said shaft by loose fitting abutting contact therewith such that said first roller bearing element moves along the periphery of said chamber with the external surface of said element in rolling engagement with the internal surface of said body and exerting a continuous uniform spreading action on lubricant between said surfaces.

(References on following page) References Cfified in the file of this patent UNITED STATES PATENTS 512,438 1,459,841 Mitchell June 26, 1923 igg z 2,422,639 Wenander June 17, 1947 3 2 2,479,799 Wilde Aug. 23, 1949 5 1 67 2,785,577 Nordegren Mar. 19, 1957 6 FOREIGN PATENTS Belgium July 15, 1952 France June 17, 1953 France Sept. 8, 1954 France June 8, 1955 (Addition to No. 1,063,465)

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