US3180624A

US3180624A - Vibrator mounting means

Info

Publication number: US3180624A
Application number: US257436A
Authority: US
Inventors: George L Malan
Original assignee: Individual
Current assignee: Individual
Priority date: 1963-02-11
Filing date: 1963-02-11
Publication date: 1965-04-27
Anticipated expiration: 1982-04-27

Description

United States Patent VIBRATQR MOUNTING MEANS George L. Malian, 560 E. Rowland, Apt. G3, Covina, Calif. Filed Feb. 11, 1963, Ser. No. 257,436 12 Claims. (Cl. 259-4) This invention relates to vibrators, and particularly to fluid-powered vibrators for settling and distributing masses of concrete.

Concrete vibrators, depending on their size, generally weigh in the range of between about 15 to 100 lbs, and have diameters between about 1 /2 to 8 inches. The vibrator unit is usually attached directly to a handle, which handle is grasped by one or more men and thrust by them into the concrete mass in order to vibrate and thereby to settle and distribute it.

In light construction, such as building foundations and walls, pillars, and the like, vibrators are used whose diameter and weight are-quite small. They can easily be manipulated by one person. Furthermore, the concrete used in such work is usually quite plastic, and the 'rock size used in theconcrete is relatively small. In view of this, there is no particular difficulty involved in the present technique of manipulating vibrators on light construction. One man can readily handle the vibrator, and the jobs are small and do not take a very long time. It therefore appears that present vibration techniques are generally suitable for this class of concrete work.

However, in heavy concrete work, such as in the building of dams, powerhouses, and other massive structures, it is customary to utilize rubble rock in the concrete, which rock may have dimensions on the order of 6-8 inches. Furthermore, the concrete used is usually very stiff, the water content being held to aminimum. In this class of construction, it is still common practice for the vibrators to be manipulated by hand, even though their weights and diameters are quite large. This is heavy, hard work. Some vibrators of this type can be manipulated by one man working alone, but'many require two men. All of them require at least one man, and no means yet has been devised which enables one man to manipulate more than one of such vibrators at a time.

Vibrators for heavy construction work have almost uniformly used compressed air power. This is because compressed air mains are conveniently provided on most construction sites for several purposes, only one of which is to supply power for vibrators. The pressure mains are usually large in diameter and capacity, and are an ordinary and expected expense in such vconstruction. in View of the convenience of this power supply, and the state of the vibrator art, the disadvantages in labor costs and the requirement for heavy manual labor have been tolerated.

There is-presently developing a need for vibrators which operate at relatively higher frequencies and with relatively higher output energies and'eiiiciencies than are attainable 'withlcompressed air. These are, as a practical matter,

attainable only by using high pressure, incompressible liquids for power. However, it is not feasible to provide a separate set of mains and a separate central power plant for supplying pressurized fluids to vibrators alone.

Besides, the operating pressure for liquids will be much higher than those for compressed gases, and the mains would have to be heavier and more expensive thanpresently-used, lower pressure air lines. It is therefore to be anticipated that as liquidepowered vibrators are further developed, there will have to be provided vehicles for carrying pumps to supply the pressurized liquid. Such vehicles will, of course, be moved along the pour, and

' be closely adjacent to the concrete being vibrated.

3,180,624 Patented Apr. 27, 1965 The presence of this type of vehicle at the pour gives rise to the opportunity for thrusting the vibrator into the concrete mass by mechanical means rather than by hand, and also of enabling one man mechanically to manipulate more than one vibrator at a time through controls and power units mounted to the vehicle. This oflers the opportunity for considerable savings in labor and other expenses.

The use of Vehicles requires that there be a relatively flexible coupling between the vibrator and the vehicle, so that vibratory energy is not dissipated in the thrusting means and the vehicle, but instead is largely exerted in the pour by the vibrator. A preferred type of coupling is an inherently flexible, tube between the thrusting means and the vibrator. However, this theoretically desirable coupling introduces two basic problems, that of too much flexibility at times, and of too little flexibility at others. These problems principally arise when vibrators are used in vibrating very stifl concrete wherein heavy rubble rock is used.

First, in regular operation, the coupling should be sufficiently flexible that a maximum amount of vibratory energy is exerted in the pour immediately adjacent to the vibrator. A st fl coupling would transmit too much of that energy to the vehicle, which is undesirable both from the standpoint of waste of energy and from wear and tear on the vehicle and its operator. This problem is not important in hand-held vibrators, because the handle is usually quite light in comparison with the vibrator, and the operator holds it loosely, thereby acting himself as a flexible link. However, this solution is not available in a heavy vehicle.

Second, it is necessary to exert considerable end force at times in order to make the vibrator enter into a pour and displace relatively stationary heavy rock which may block its way, or to force its way through a formation when it acts as a drill. If a very flexible coupling is used, the possibility exists that the coupling could completely buckle, thereby either destroying itself or largely eliminating end loads. This condition would tend to limit the utility of vibrators in resistant environments, because while a flexible coupling is often needed, so is considerable stifiness at other times for exerting large end loads. These requirements are contrary to each other, and it is .difiicult to effect a compromise. Instead, an adjustable,

controllable device is called for.

Third, the situation sometimes arises in a pour where a controlled deflection of the vibrator relative to the handle or thrusting means is desirable to enable the vibrator to bypass an obstruction and then to exert sidewardly directed blows on it which would tend to shift the obstruction sidewise. This is effective in moving rock out of the way which cannot be deflected by a pure axial load. When hand-held vibrators are used, this is accomplished merely by tilting the handle, thereby accomplishing the desired forces on the obstruction. However,

in deep wells, or in the use of vehicle-mounted vibrators,

such a technique is not attainable, because in these the ,center of rotation of the movement is at the point of attachment, which is far away from the point around which the vibrator should rotate.

In connection with all of these considerations, it should be borne in mind that a conventional vibrator exerts sub- ,stantially only lateral forces. The only axial forces ex- .erted by it are those which are derived from thrust on the handle. I

An object of this invention is to'provide a coupling for a vibrator, the rigidity of which is variable in response to the condition the vibrator encounters, and which rigidity in a preferred embodiment automatically varies in response to the load on the vibrator.

3 This invention is carriedrout in combination with a vibrator and the handle. It includes an inherently flexible coupling, which is preferably also elastic, and which joins the vibrator and handle in axially-aligned and spacedapartrelationship. Means is provided for exerting fluid pressure Within the coupling to place it in axial tension,

the flexibility of the coupling thereafter being a. function of its internal pressure and of the axial compressive end loading on it. Control of the rigidity of the couplingis derived from .the controllability of the internal pressure.

According to one preferred but optional feature of this invention, the pressure inside the coupling is automatically adjusted as a function of the load on the vibrator.

According to still another preferred but optional fea ture of this invention, the handle is mounted to the vehicle through means Whose direction of thrust relative to the vehicle is adjustable, thereby providing means for an operator to select the point and direction of insertion of the vibrator into a pour.

The above and other features of this invention will be fully understood from the following detailed description and the accompanying drawings in which:

FIG. 1 is a side view, partly in cutaway cross-section, showing the presently preferred embodiment of the invention;

FIG. 2 is a cross-section taken at line 22 of FIG. 1;

FIG. 3 shows the device of FIG. 1 in one operating position; and

FIG. 4 is a cross-section of still another embodiment of the invention.

FIG. 1 shows the presently preferred embodiment of the invention mounted to a vehicle 10. An axial thrust means 11 comprising a hydraulic cylinder 12 and extensible piston rod 13 is mounted to the vehicle by hinge 14. Rod 13 carries a thrust collar 15.

A direction control means 16 is also attached to the vehicle by a hinge l7 and includes a cylinder 18 and an extensible piston rod 19. The piston rod is connected to cylinder 12 by another hinge 20. The axes of all of the hinges are parallel.

Rods

13 and 19 are connected to axially shiftable pistons (not shown) inside their respective cylinders. Means 11 and 16 are provided with hydraulic connections, power or the coupling is shown in FIG, 1.

be made of rubber. The inside free length of. the tube is exposed to exhaust pressure fromthe vibrator. This pressure tends to thrust t e handle and vibrator apart, placing the tube in axial tension. It also tends to apply expansive forces thereon.

The properties and dimensions of:the tube will be selected to resist ready bending, but tobe inherently flexible. Axis 41 is the common axis or the handle, coupling and vibrator when they are at rest." T he'thrust' control means and the direction control means are adjusted to exert axial thrust to force the vibrator in the desired direction. The vibrator is placed in operation by applying pressure to the pressure lines, and in operation exerts unbalanced lateral forces. Obviously there will be some side deflection of the vibrator relative to the axis of the handle whenever the vibrator operates, because-the coupling is inherently flexible, and this is desirable in order to exert maximum energy in the pour, and minimum energy in the handle and on the vehicle. However, the inherent flexibility of the tube is lessened by axial tension to which the tube is subjected by the fluid pressure, and this stiffens the coupling when stiffness is desired. Conversely, lessening of the axial tension by an axial compression force lessens the rigidity and renders the coupling more flexible.

The control system for both automatically and manually regulating ti e flexibility, and conversely the rigidity, Aclosed, hermetically-sealed reservoir Suhas a pressure dome 5?. which is connected to a first chamber 52 of a differentialpressure accumulator its second chamber 54 has a lesser cross-sectional area. than the first chamber. A difierential piston is slidedly fitted in the two chambers. A vent port fi'is formed through the accumulator wall just above the region traversed by the lower portion or" units and controls (not shown) which are manipulated by an operator for extending and retracting the respec- Ahandle 3% includes a thrust collar 51 which abuts and is attached to thrust collar 15. The handle includes a central flexible pressure line 32 adapted to be connected to a source of pressure through line 33 and to the pressure port of the vibrator. It is surrounded by coaxial exhaust line 34 and to an exhaust line 35. The

handle also includes a reduced neck end 36.

A coupling generally designated by numeral 37 comprises a tube 38, which surrounds and is attached to neck ends 23 and 36 by

bands

39, 40 or any other suitable means. The tube spaces the neck ends apart along axis 41 of the vibrator, and joins thetwo.

support between the handle and vibrator. The only sub- The central exhaust line is not intended to provide any structuralv stantial structural support for the vibrator from the loan a die is intended to be exerted by the coupling. The cou-.

pling is inherently flexible, but still enough to resist bending. It may, for example, have an axial length of about 7 inches with a free length between the neck ends of about 3 to 4 inches. For" a 6-inch diameter vibrator operating at about 1000 p.s.i.g., the wall thickness of this tube may be about to 1 inch and may conveniently the piston to ventthe same,

The hydraulic system is closed, and not vented to atmosphere in order that the exhaust pressure may be regulated. Liquid 57 does not'entirely fill the pressure dome, but leaves a region therein above the liquid, which is occupied by a gas. This region is connected to the first chamber, of the accumulator. The purpose of the differential pressure accumulator is to step down the pressure from the pump, from which the accumulators basic pressure is derived. J

A constant delivery pump 58 withdraws liquid'frorn the reservoir and pumps it from line 59 to line. 6th, line as being connected to line 33.. A throttle valve 61 is provided in line oil. A constant; speed motor 62 drives pump 58. This motor and pump deliver a predetermined volume of liquid per unit time, but the absolute pressure at which the liquid is delivered depends upon the back pressure in the system and on thedemand of the vibrator.

Line 60 is side-tapped by side 63 which discharges into one port of a selector valve 64. Line 65 connects another port of the selector valve to the. second chamber of the accumulator.

Line 66 interconnects still another'port-a of the selector valve to the reservoir through a bleed-type regulater 67 and a pump 68. The selector valve can be set 'to-disconnect all of its lines from each other, or to connect lines 60 and 65 or lines 65 andoo.

Line 69; connects exhaust line 35 to the reservoir. A variable restrictor may, if desired, be placed in line 69.

FIG. 4 illustrates the broad scope of the invention, as applicable to flexible couplings in general, whether. also elastic or not, so long as the coupling can be placed in axial tension which is opposable by axial compressive forces; Handle 30 and vibrator 21 are shown joined by a coupling 100, which is a .ball joint. Pressure line 32 and exhaust line 3 pass through the coupling.

The handle neck has been. modified by a ball 101, and

the vibrator neck'has been modified by a seat Hi2. A

retainer 1% has a seat 1% which is threaded onto the neck, the ball being trapped between seats Th2 and 104. This ball jointis inherently flexible around the center of the ball. .In accordance with conventional construction, a very small clearance is left between the seats and the ball to permit these surfaces .to be lubricated. Conventional seals (not shown) may be provided between the seats and ball surfaces to minimize leakage and confine the lubricant, if desired.

The operation of the device of FIG. 1 will now be described. Rotarydevices such as vibrators require a given volume-rate of flow per unit time in order to operate at a given frequency. They will operate at a frequency determined by the rate of flow, although the working pressure may vary. The pressure drop across a vibrator (that is the differential pressure between the pressure and exhaust lines) will increase as the load on the vibrator increases, and decrease as the load decreases. In general, the lightest load in vibrators of this class will occur when the vibrator is running free in the air, and the heaviest load occurs when the vibratoris placed in a stiff, but still plastic medium, such as stiff liquid concrete of low water content,

"but not in the condition in which it is firmly grasped by relatively rigid and immovable rock.

In order for a given volume of fluid to be pumped through the vibrator when it is under load, the inlet pressure must be raised. With the constant speed motor and constant delivery pump shown in FIG. 1, this merely places a heavier load on the motor and its energy supply. However, the pressure generated by the pump will rise.

Furthermore, in a closed unvented system such as that shown in FIG. 1, the inlet pressure differs from reservoir pressure by an increment equal to the pressure drop and line loss. It follows that exhaust pressure relative to atmosphere can be regulated in order to control the pressure inside the coupling, which in turn raises the inlet pressure, but leaves the differential pressure between inlet and exhaust lines substantially unaffected. The pressure in the exhaust line thereby is variable with the load on the vibrator, and by the back pressure exerted from the reservoir. This latter provides means for controlling the flexibility and rigidity of the coupling.

Assume that pump 58 is running so as to deliver its prescribed volume, and that the throttle valve is wide open. The selector valve is set to connect

lines

33, 60 and 65. This sets the reservoir pressure (which is the pump inlet pressure and coupling pressure) at a lower value than pump output pressure, this value being determined by the ratio between the cross-sectional areas of the chambers. Thus, the backpressure in the reservoir and on the exhaust side of the vibrator, is established by the output pressure of pump 61.

Assuming thatthe vibrator is running at a light load, the pressure diflerence between

lines

32 and 34 is at a value toward its minimum, and the system adjusts itself accordingly, the pump output pressure also being at a working minimum to supplythe pressure differential required. Because the differential is small, the pump output pressure is relatively small, and so is the pressure inside the coupling. Now when'the vibrator is placed under a heavier load, the differential pressure acrossit, that is, the working pressure to force a constant volume of fluid per unit time, through the vibrator increases. Therefore the output pressure of the pump increases, a heavier load being placed on motor 62.

An increase in the output pressure raises the accumulator, reservoir, and coupling pressure, and the pump output pressure adjusts itself accordingly. The important result of this is an increase in the back pressure in the coupling.

' A similar result could have been secured by adjusting restrictor 70, but it is uneconomical to use restrictor valves in this type of circuit merely to control pressures, because of the amount of work it takes to pump fluid through them. The accumulator adjusts the pressures without wasting energy. Therefore, restrictor 70 is not to be preferred, and if present is usually kept wide'open.

When the coupling pressure increases, its stiffness in- 6 creases, and it will be noted that this occurred in the above example when the load increased. An increased load might reflect the'meeting of an end-loading obstruction of the type a strong axial push could overcome, such as in drilling operations, for example. This coupling, which is relatively flexible in normal running operation, becomes stiffer with increased load, which is one useful way to operate it.

Another mode of operation is to preset the reservoir or back pressure to some value, such as by connecting lines 65 and 66, and using pump 68 and bleed-type regulator 67 to maintain a constant pressure in line 65. The regulator shown maintains pressure in line 66, and discharges excess fluid through line 71 to the reservoir. With this arrangement, the coupling has a preset pressure level, and any end load will oppose this level, thereby rendering the coupling more, instead of less, flexible, as shown in FIG. 3. The difference here is that the elongating force is constant, and can be overcome by the compressive force to render the coupling more flexible, while in the previous example, an increasing load made the coupling more rigid.

Thus, the coupling is made versatile to cope with various situations. When a more rigid coupling is needed in order to axially pierce a region, it is available. When a more flexible coupling is needed to provide for side flailing, that too is available. In both arrangements, a normal flexibility is available for normal operations.

When the ball joint is provided, the results are the same. The additional or lesser loadings result in greater or lesser flexibility. Furthermore, the elongating forces tend to overcome the compressive forces, thereby enabling lubrication to reach the adjacent surfaces, thereby overcoming the cause of many ball joint failures, is. lack of lubrication at strongly forced-together abutting, relatively sliding surfaces. The ball'joint is, therefore, a mechanical equivalent of the flexible but elastic tube in many important respects.

I The term vehicle as used herein is not intended to be limited to any particular class of mobile element. In fact, the vehicle, might be skid-mounted, wheel-mounted, or track-mounted, or merely stand on a base. The term vehicle is intended to define a supporting structure which is subject to being moved, either under its power, or by being lifted or shoved around by any means, without limitation as to the exact nature of the supporting means or of the motive means.

This device thereby provides a convenient means whereby a vibrator may be vehicle-mounted and rendered more able to move into resistive bodies.

This invention is not to be limited by the embodiment shown in the drawings and described in the description which is given by way of example and not of limitation, but only in accordance with the scope of the appended claims.

' I claim: 1

1. In combination: a vibrator having an inlet and an exhaust outlet; a handle; and a coupling for mounting the vibrator to the handle, said handle, coupling and vibrator having coincident longitudinal axes, and the vibrator being adapted to exert unbalanced lateral vibratory forces, the coupling joining the vibrator and handle, and holding them in axially spaced-apart relationship, the coupling comprising a tube of inherently flexible and elastic material; pressure means for supplying fluid under pressure to the vibrator inlet to operate the same; and back-pressure means in fluid connection between the coupling and the pressure means, whereby the vibrator and the coupling are in series connection in a fluid circuit, pressure in the coupling being variable as a function of the differential pressure between the inlet and the exhaust outlet.

2. A combination according to claim 1 .in which the pressure means, vibrator, back-pressure means and coupling are formed in a closed, unvented system.

3. In combination: a vehicle; a vibrator having an inlet oneness and as exhaust outlet; a handle; a coupling for mountingv the vibrator to the handle; axial thrust means attached to the handle and to the vehicle;direction control means attached to the vehicle and to the axial thrust means, the handle, coupling, vibrator and axial thrust means having coincident longitudinal axes, the vibrator being adapted to exert unbalanced, lateral vibratory forces, the coupling joining the vibrator and handle, and holding them in axially spaced-apart relationship, the coupling comprising a tube of inherently flexible and elastic material; pressure means for supplying fluid under pressure to the vibrator inlet to operate the same; and back pressure means in fluid connection between the coupling and the pressure means, whereby the vibrator and the coupling re in series connection in a fluid circuit, pressure in, the coupling being variable as a function of the differential pressure between the inlet and the exhaust outlet; the axial;

thrust means being adapted to move the vibrator and handle in axial directions, and the direction control means being adapted to select that direction. 7

4. A combination accordingto claim 3 in which the axial thrust means and direction control means each com: prises a piston-cylinder assembly.

5. A combination according to claim 3 in which said pressure means is adjustableto vary the said pressure.

6. A combination according to claim 3 in which said pressure means is a closed unvented liquid system in-.

cluding a constant delivery pump, back pressure on the system constituting the fluid pressure in the tube.

7. A vibrator system of adjustable rigidity, comprisingz.

a vibrator having a fluid pressure inlet and an exhaust outlet; a handle; a coupling for mounting the vibrator to the handle, said handle, coupling and vibrator having coincident longitudinal axes, and the vibrator being adapted to exert unbalanced lateral vibratory forces, the coupling joining the vibrator and handle, and holding them 1 in axially spaced-apart relationship, the coupling comprising a tube of inherently flexible and elastic material; a

pressure source; a pressure line connecting the pressure source to the fluid pressure inlet of the vibrator; a closed, unvented reservoir; an exhaust line which includes the tube connecting the exhaust outlet to the reservoir; the pressure source comprising a constant delivery pump withdrawing fluid from the reservoir; and means for raising the reservoir pressure as a function of raising pump output pressure.

8. A vibrator system of adjustable rigidity comprising: a vibrator having a fluid pressure inlet and an exhaust outlet; a handle; a coupling for mounting the vibrator to the handle, said handle, coupling and vibrator having coincidence longitudinal axes, and the vibrator being adapted to exert unbalanced lateral vibratory forces, the coupling joining the vibrator and handle, and holding them in axially spaced relationship, the coupling comprising a tube of inherently flexible and elastic material; a pressure source; a pressure line connecting the pressure source to the fluid pressure inlet of the vibrator; a closed, un-

source comprising a constant delivery pump withdrawing fluid from the reservoir; and means comprising anaccumulator, one side of which is connected to the pump outlet pressure, and the other side of which is connected to the reservoir, for raisingthe reservoir pressure as a function of raising pump output pressure.

9. A, vibrator system according to claim 8 inwhich the accumulator is a differential pressure type, whereby pres sure maintained by it in the reservoir is less than pump output pressure.

10. Avibrator system accordingto claim 8 inwhich an alternate,variable pressure source, is provided to adjust the accumulator pressure independently of the pump output pressure, and in which a selector valve is provided to select between pump output pressure and said alternate source.

'11. A vibrator system of adjustable rigidity, comprising: a vibrator having a fluid pressure inlet'andfan exhaust outlet; a handle; a couplingfor mounting'the vibrator to the handle, said handle, coupling and vibrator having coincident longitudinal axes, and the vibrator being adapted to exert unbalanced lateral vibratory forces, the coupling joining the vibrator and handle, and holding them in axially spacedsapart relationship,.thecoupling comprising an inherently flexible ball joint; a pressure source; a pressure line connecting the pressure source to'the fluid pressure inlet of the vibrator; a closed, unvented reservoir; an exhaust line which includes the ball joint connecting the exhaust outlet, to the reservoir; the pressure source comprising a constant-delivery pump withdrawing fluid from the reservoir; 'andm'eans for raising the reservoir pressure as a function or" raising pump output pressure.

12. In combination: a vibrator; a handle; and a coupling for mounting the vlbratorto the'handle, said'handle, coupling and vibrator having coincident longitudinal axes, and the vibrator being adapted to exert unbalanced lateral vibratory forces, the coupling joining-the vibrator and handle, and holding them in axially spaced-apart relationship, the coupling comprising an inherently flexible ball joint; and means for exerting'fluid pressure Within the ball joint to place it in axial tension, whereby the ball joint is inherently stifierand tends to resist bending, compressive end-loading'tending to overcome at least some of the axial tension and 'render the ball joint less rigid.

References Cited by thelExarnlner UMTED STATES PATEN' I S I 2,059,239 1 11/36 Jackson 25972 2,148,722. 2/39 Baily 259-1 2,215,888 9/40 Swarthout 259--1 2,308,712 1/43 Peterson et al. 2,763,472 9/56 Fontaine; 2591 3,020,720 2/ 62 Spalding. 3,111,177 11/63 j Osgood 173--36 CHARLES A.W1LLMUTH, Primary Examiner.

Claims

1. IN COMBINATION: A VIBRATOR HAVING AN INLET AND AN EXHAUST OUTLET; A HANDLE; AND A COUPLING FOR MOUNTING THE VIBRATOR TO THE HANDLE, SAID HANDLE. COUPLING AND VIBRATOR HAVING COINCIDENT LONGITUDINAL AXES, AND THE VIBRATOR BEING ADAPTED TO EXERT UNBALANCED LATERAL VIBRATORY FORCES, THE COUPLING JOINING THE VIBRATOR AND HANDLE, AND HOLDING THEM IN AXIALLY SPACED-APART RELATIONSHIP, THE COUPLING COMPRISING A TUBE OF INHERENTLY FLEXIBLE AND ELASTIC MATERIAL; PRESSURE MEANS FOR SUPPLYING FLUID UNDER PRESSURE TO THE VIBRATOR INLET TO OPERATE THE SAME; AND BACK-PRESSURE MEANS IN FLUID CONNECTION BETWEEN THE COUPLING AND THE PRESSURE MEANS, WHEREBY THE VIBRATOR AND THE COUPLING ARE IN SERIES CONNECTION IN A FLUID CIRCUIT, PRESSURE IN THE COUPLING BEING VARIABLE AS A FUNCTION OF THE DIFFERENTIAL PRESSURE BETWEEN THE INLET AND THE EXHAUST OUTLET.