US 3772923 A
An intermittently driven eccentric weight rotary vibrator with matched dual or coaxially concentric weights rotatable relative to each other about a common axis, which eccentric weights normally are urged to assume an additive eccentric position except when rotarily driven at which time the driving forces place the eccentric weights in balance during these alternate driving periods. The attained speeds of the balanced weights are above the critical speed required for vibrating the loaded object to which the rotary vibrator is attached. During the alternate retarding periods, the eccentric weights in their eccentric additive positions transmit their vibratory motion to the loaded object to be vibrated at the critical speed of the same. The driving period represents only a short part of each operating cycle and the retarding periods provide a declining series of spaced critical nodes effective in producing vibrations over a period of approximately one minute. The energy driving or storage period may be one-tenth of the vibratory period with the total cycle being approximately one minute. This improved result is due to the constuction of the vibrator and its parts with very little drain on the energizer, which is usually a motor driven by a battery.
Description (OCR text may contain errors)
United States Patent 1191 Burt 1451 Nov. 20, 1973 21 Appl. No.: 230,806
52 US. Cl. 74/61, 198/220 DB, 209/3665 51 Int. 01. Fl6h 33/00  Field of Search 209/3665, 367, 326;
 References Cited UNITED STATES PATENTS 2,078,715 4/1937 Lurz et al. 74/61 2127 311 8 1938 Welch 2 sea 210 i 312 1958 Fisher 977, 09 4 1961 Becker et al FOREIGN PATENTS OR APPt'I' 415,309 /1933 GreatBritain..... l
Primary Examiner-Charles J. Myhre Assistant ExaminerWesley S. Ratliff, Jr. Attorneyqarothers & Carothers  ABSTRACT An intermittently-driven eccentric weight rotary vibrator with matched dual or coaxially concentric weights rotatable relative to each other about a common axis, which eccentric weights normally are urged to assume an additive eccentric position except when rotarily driven at which time the driving forces place the eccentric weights in balance during these alternate driving periods. The attained speeds of the balanced weights are above the critical speed required for vibrating the loaded object to which the rotary vibrator is attached. During the alternate retarding periods, the eccentric weights in their eccentric additive positions transmit their vibratory motion to the loaded object to be vibrated at the critical speed of the same. The driving period represents only a short part of each operating cycle and the retarding periods provide a declining series of spaced critical nodes effective in producing vibrations over a period of approximately one minute. The energy driving or storage period may be one-tenth of the vibratory period with the total cycle being approximately one minute. This improved result is due to the constuction of the vibrator and its parts with very little drain on the energizer, which is usually a motor driven by a battery.
9 Claims, 10 Drawing Figures PMENTED NOV 20 1973 sum 1 u 3 1 ECCENTRIC WEIGHT ROTARY VIBRATOR BACKGROUND OF THE INVENTION Intermittently driven rotary eccentric vibrators are not new in the art or in commercial use. They are used for vibrating hopper cars, trucks and to aid in discharging their contents as well as for vibratory motors for operating screens, conveyors and other material moving devices. A principal reference is the Plant U.S. Pat. No. 2,673,651, where one weight unit has limited movement on a rotary shaft relative to a second weight unit fixed to a shaft system with two sources of drive means to place the weights in balanced position or additive eccentric position. Many of the other patents such as Stroud U.S. Pat. No. 2,528,620, have a similar weight structure with a single drive and provided with a spring structure to normally maintain the weights in a balanced position and not in eccentric position as in this invention.
SUMMARY OF THE INVENTION The present invention is based upon a different concept of requiring the accelerating force of the driving action to place the weights in balanced position and a spring to draw the weights into additive eccentric position which requires a very short accelerating period by the driving force and a materially longer decelerating or vibratory period making up the full intermittent operating cycle which may occur once every minute or thereabout. With this novel structure, the spring could be eliminated entirely, but predetermined positive operating conditions are assured by the use of the spring at constant speeds or during the retarding periods.
One object of this invention is the form of the eccentric weight structure which is preferably a cast wheel having a hub, a flange and a rim weight, a part of the latter being omitted to produce the eccentric weight.
Another object is the provision of mounting and employing the cast wheel weight unit. When used as a pair, the weights being identical will balance each other and one weight unit is fixed to a rotary driven shaft while the other weight unit is journaled thereon to have relative aligning movement to produce a balanced position and an unbalanced position of the weight units. Thus, one weight unit is secured to the shaft by a wedged sleeve or any other desired means while the second weight unit is supported by a frictionless bearing on the same shaft and provided with a stop which may or may not be located at 180 positions, or may be adjustable to obtain different effects.
If four weights are employed, the two weights that are fixed to the rotary shaft are placed on opposite sides of the relative rotary weights which may be secured to each other. Thus, in their symmetry, the four weights function as a two-weight system.
The other weight system is made by mounting coaxial concentric weights on the same rotary shaft, the fixed weight entirely enclosing the relatively movable weight supported by anti-friction bearings on the shaft. The four-weight system may also be provided with an outer cylindrical cover for the system to effect the same results. An enclosed system of this character may be hermetically sealed and supplied with a lubricant mist for the enclosed bearings if they are not of the sealed type.
Assuming a spring is not provided, the accelerating force makes the movable weight stop at the balanced position of the weights. When not driven, or driven at a constant speed, the movable weight is naturally moved to the unbalanced or additive eccentric position. If two or more identically driven vibratory systems are mounted on a single object to be vibrated, they will function in synchronization for the same reasons as the automatic synchronization of eccentric weights driven in opposite directions of the Signeul U.S. Pat. No. 2,531,706; Canadian Patent 516,381 to provide linear vibrations; French Patents 905,601 of 1945 and 888,521 of 1943; and Swedish Patent 163,270. Although these structures include a spring suspended body, the weight systems must be rigid relative to each other.
A principle feature of this invention is that the vibrator can be changed from balanced operation to eccentric operation at any speed desired by reducing the accelerating force below the spring force, and it can be put back into balanced operation at any speed if the accelerating force is increased above the spring force. Thus, with the spring means applied, this action is made positive and predictable.
Other objects and advantages appear in the following description and claims.
The accompanying drawings show, for thepurpose of exemplification without limiting the invention or the claims thereto, certain practical embodiments illustrating the principles of this invention wherein:
FIG. 1 is an isometric view of an eccentric weight member comprising this invention.
FIG. 2 is a view in vertical elevation with parts shown in section illustrating an assembly of four eccentric weights on a base.
FIGS. 3 and 4 are cross-sectional views of the coaxial concentric eccentric weights respectively showing their weights in-their normal additive eccentric position and their balanced position when being driven.
FIG. 5 is a view of a coaxially concentric eccentric weight structure shown in section and connected through a free-wheeling clutch and couplings to a motor drive and provided with an internal atmosphere control.
FIG. 6 is a graph illustrating a single cycle operation substantially one minute in length wherein the acceleration time is approximately 10 seconds and the deceleration time is approximately 60 seconds.
FIG. 7 is an RPM speed graph illustrating acceleration with weights in balance and applied with rotary power to accelerate from zero speed to a maximum speed above the critical speed of the object to be vibrated, and the power off time during the deceleration period with the full eccentricity of the weights applying their vibration to the load at different harmonic amplitude positions of deceleration within the cycle shown in FIG. 6.
FIGS. 8(a), (b) and (c) are respective diagrammatic views illustrating respectively two weights between spaced bearing mounts, two weights on opposite sides of single bearing mounts, and four weights on opposite sides of a single bearing mount.
Referring to FIG. 1 of the drawings which shows the simplest structural form of one eccentric weight forming one part of this invention. This weight may be machined, but is preferably cast. This eccentric weight is a rim or fly wheel weight wherein the hub 10 is provided with a bore 11. One end of the hub 10 has the integral radial flange 12 which extends through 360 and the perimeter of this flange is formed integral with the rim weight 13 of which a section of approximately 90 is omitted, as shown in FIG. 1, permitting one to view the end faces that lie in plains radial to the axis 14 of the weight, thus providing an eccentric weight of which two or more pairs form an eccentric rotary vibrator.
Since the bore 11 of each weight is sufficiently large, it may receive the tapered bushing 15 secured thereto by bolts such as illustrated in the bores of the outer weights l6 and 17 of FIG. 2. These bolts together with the tapered bushing 15 tightly secure these weights to the shaft 20, which is carried by anti-friction bearings 21 and 22 which are preferably of the tapered roller type mounted in the bearing standards 23 and 24 integral with the base 25 provided with suitable means for detachably securing this base to the object to be vibrated such as by bolting.
It will be noted that the eccentric weights are each made from the same mold and the hub 10 is spaced from the inner rim weight 13 providing an annualar chamber 18. The hubs of the inner pair of eccentric weights 26 and 27 face each other to enclose their chambers 18, and the bore 11 of each is provided with an anti-friction bearing 28 on the shaft 20 in the vicinity of their radial flanges 12. This pair of weights 26 and 27 are secured to each other as by welding around their perimeters as indicated or by bolting (not shown).
The outer pair of eccentric weights 30 and 31 are assembled with their chambers 18 facing the flanges 12 of the inner pair of weights so that one of these chambers 18 may be employed to receive the helical spring 32, one end of which is secured relative to the shaft 20 through the cylindrical hub 10 by the bolt 33 on the weight 30 and the opposite end is secured through an eye formed in the outer end of the spring 32 by the bolt 33' threaded into the flange 12 of the weight 26.
The chamber 18 of the weight 31 has secured thereto the stop 34 to engage the stop 35 on the flange of weight 27 when the shaft 20 is accelerated causing the weight systems to balance each other. This condition is maintained until they exceed a critical speed and the excitation of the exciter or driving element is cut off, at which time the helical spring 32 causes the stop 35 to engage the stop 34 180 out of phase from the position shown in FIG. 2. The stop 34 in the chamber 18 of the weight 31 places the weights in added eccentric position when both sets of weights are traveling at their highest critical speed. The vibratory action created by the added eccentricity of both sets of weights is then applied through the base 25 to the load to be vibrated.
The exciter or motor drive 37 is secured to the right end of the shaft 20 shown in FIG. 2, and a centrifugal switch 38 is connected to the shaft 20 indicated at the left.
The eccentric weights may be enclosed and hermetically sealed by a cylindrical enclosing drum 40 secured to the perimeter weights 30 and 31 and enclosing their open end sections, where the omitted portions of the rim weight 13 occur. A desired atmosphere may be supplied through a sealed valve on the side of this cover or drum 40 or through the rotary shaft 20 to the chamber created by the enclosing drum 40. This drum 40 is built upon the perimetral ends of weights 30 and 31 to provide clearance with the central pair of weights 26 and 27.
A coaxial concentric rotary eccentric weight structure is shown in the cross-sectional views of FIGS. 3, 4 and 5, wherein the inner eccentric weight 41 is arcuate and must balance the outer eccentric weight 42 as shown in FIG. 4 and is engaging the stop 43 in its balanced position. In FIG. 3, these weights are shown in their additive eccentric position. Since these weights are substantially semi-circular, the single stop 43 on the weight 42 makes both eccentric weights additive for vi brating the object during the deceleration period.
As shown in FIG. 5, the spaced discs 44 and 45 are preferably circular to accomodate the helical spring 32 fastened to the shaft 20 at its inner end by the bolt 33 and by bolt 33' to the disc 44 at its outer end to normally maintain these eccentric weights in their added position of eccentricity for providing vibratory power to the object to be vibrated. The outer cylindrical weight is also provided with spaced heads 46 and 47 hermetically sealed with the shaft 20 and secured thereto such as by the shaft keys shown, and connected by a cylindrical housing 48 of sufficient strength to rotatably support its eccentric weight 42 and rotatably carried by the bearing standards 23 and 24. A standard 50 is provided on the left end of the shaft to provide a sealed connection to the inner chamber of the drum 48 to provide an atmosphere with a lubricant mist.
Thus, the structure of FIG. 5 as well as that of FIG. 2 provides a rotary eccentric vibrator with a base for connection to the object to be vibrated. The matched pairs of eccentric weights are the coaxially concentric weight structures. The weight that is realtively movable is in both instances of FIG. 2 and FIG. 5 the innermost weight units 26 and 27 and the discs 44 and 45 supporting the inner weight 41 respectively. The stop means 43 is on the outer weight means effective to engage the inner weight means, and the spring 32 is effective by attachment relative to the shaft 20 to position these weights in their additive eccentric position during the deceleration period as set forth in this disclosure and the claims therefor.
The opposite end of the shaft 20 may have an over running clutch 51 to disconnect the drive 37 while the vibrator is performing. In some instances, it may be preferable to retain the drive 37 or vibratory energizing system solidly connected with the shaft and function to have a continuing fly wheel effect to obtain the proper vibratory pattern of the declining amplitude peaks that occur at spaced harmonic positions during the decelerating periods.
FIG. 6 shows a typical curve which demonstrates approximately 10 seconds to drive or accelerate this eccentric weight system in balanced position to attain the speed of 1,200 RPM and provide substantially seconds to redeliver this energy through the additive rotary eccentric vibrations to the object being vibrated. These periods, as shown in FIG. 7, may be changed by proper selection of the speed of drive for the chosen eccentric weights, together with the character of the truck body or railroad car or other body being vibrated and the conditions of the materials being moved, conveyed or discharged.
A series DC motor operated from a twelve volt battery system can properly wind up this eccentric weight system in ten seconds or less and will not drain the battery in this character of intermittent operation. The balance of the weights with a heavy vibratory discharge through the critical speeds is obtained by the use of adequate anti-frictional bearings in the whole system which is an important object and providing the success of this invention and structure over known devices.
Various arrangements of the vibratory weight means are shown in FIGS. 8a, 8b, and 80, wherein in FIG. 8a there are only two weight units between spaced bearings, which is somewhat similar to that of FIG. 2. In FIGS. 8b and 8c, the single bearing mount 23 and 24 is positioned between two weight units or weight sys tems of four weight units and the shaft 20 provides a compact unit with either arrangement of eccentric weights. The application has much to do with the structure of this rotary eccentric vibratory motor.
This structure has other advantages particularly in having a single eccentric weight casting to provide multiple vibrators at strategic places on one object to be vibrated which will maintain synchronism without being rotarily connected.
1. A rotary eccentric vibrator comprising a base for attachment to an object to be vibrated,
a rotary shaft means supported in frictionless bearing means mounted on said base to be accelerated, first eccentric weight means fixed on said shaft means, second eccentric weight means mounted on antifrictional bearings carried by said shaft means to provide a balanced and an eccentric weight system,
stop means effective between said first and second eccentric weight means to arrest the position of said second weight means to balance said weight system when said shaft is accelerated,
an accelerator drive means energized to accelerate said shaft means to force said second weight against said stop means with said weight means in balance,
and cutoff means to make said accelerator drive means ineffective and permit deceleration of said weight system causing their eccentric weights to be additive and transmit their total effective eccentric energy to vibrate the object to which said base is attached.
2. The structure of claim 1 characterized in that,
each of said eccentric weight means includes an eccentric weight unit comprising,
a cylindrical hub for receiving said rotary axis means,
a radial circumferential flange extending from one end of said hub,
and a rim integral with the perimeterof said radial and having considerable weight for at least a substantial portion of its circumference to form said counterweight means,
and to produce a chamber about said hub.
3. The structure of claim 2 characterized in that each eccentric weight means also includes a pair of eccentric weight units with their matched co-extensive weight sections on each rim secured to each other and to enclose their chambers with their flanges facing axially outwardly.
4. The structure of claim 1 characterized in that said first and second eccentric weight means represent an outer and inner rotary eccentric unit selectively enclosing one within the other.
5. The eccentric weight structure of claim 1 wherein said second pair of matched eccentric weight units are secured to said shaft means comprising said rotary axis means and their chambers facing the radial flanges of said first pair of matched eccentric weight units, said means to limit the relative movement between said eccentric weight means including a stop means in said chamber of one eccentric weight unit of said second pair of matched eccentric weight units and a relatively movable stop means on the flange of one of said eccentric weight units to engage said first stop means and limit the relative movement of said eccentric weight means to positions of balanced and additive eccentricity, and said automatic means including spring means in said chamber of the other eccentric weight unit of said second pair of matched eccentric weight units connecting said pairs of eccentric weight units to place them in their additive eccentric position when said shaft means is decelerated.
6. The eccentric weight structure of claim 5 which also includes an accelerator means for said shaft means to rotate said eccentric weight means in balanced relation to afore-selected critical speeds, and cutoff means for said accelerator means to permit said eccentric weight means to decelerate and impart periods of eccentric vibration through said base to the object to be vibrated when not being accelerated.
7. The eccentric weight structure of claim 5 which also includes bushing means to secure said second pair of matched eccentric weight means to said shaft means, each of said eccentric weight units being matched duplicates.
8. The eccentric weight structure of claim 5 which also includes a cylindrical enclosure attached to the peripheries of said second pair of eccentric weight units and free of said first pair of eccentric weight units to enclose and seal said eccentric weight system.
9. A rotary eccentric vibrator comprising a base to be attached to a member to be vibrated, a rotary shaft means supported by frictionless bearing means from said base to be accelerated, a matched pair of eccentric weight means fixed to said shaft means in spaced relation to each other, a second matched pair of eccentric weight means secured to each other and supported by frictionless bearing means on said shaft means between said first pair of eccentric weight means, stop means effective between said first pair and said second pair of weight means to limit the relative rotary movement of the latter relative to the former to produce a balanced weight condition of said rotary shaft means, and spring means effective between said first pair and said second is not accelerated.
j UNITED STATES PATENT-I oFFIc'E CERTIFICATE OF CORRECTION Patent No. 7721923 lj t d November 20 1973 Inventor(s) Ralph D. Burt It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:
Col. 6, ciaim 5, line 4, erase "l" and substitute --9-- line 17, delete "said automatic means including" S d and sealed this 16th dayof July 1971.
- MCCOY M. GIBSON,-JR. C. MARSHALL DANN Attesting Officer Commissioner of Patents USCQMM-DC 503764 69 U45. GOVERNMENT PRINTING OFFICE: I969 O366-334 FORM PO-lOSO (10-69)