US3813950A

US3813950A - Apparatus for producing variable amplitude vibratory force

Info

Publication number: US3813950A
Application number: US00299059A
Authority: US
Inventors: D Ebersole
Original assignee: Koehring Co
Current assignee: Koehring Co
Priority date: 1972-10-19
Filing date: 1972-10-19
Publication date: 1974-06-04
Anticipated expiration: 1991-06-04
Also published as: FR2204134A5; GB1438839A; JPS4973805A; JPS5249644B2; IT1001599B; CA983346A; DE2351945A1

Abstract

The present invention provides an apparatus for producing a variable amplitude vibratory force which is particularly useful as a rotatable eccentric for a vibratory roller. The rotatable eccentric comprises first and second eccentric fluid chambers rotatable about a common axis of rotation, and adjustable valve means interconnecting the chambers for controlling the amount of fluid transfer between the chambers upon rotation of the eccentric to produce a variable amplitude vibratory force.

Description

United States Fatent Ebersole APPARATUS FOR PRODUCHNG VARKABLE AMPLHTUDE VHERATORY FO RCE D. Henry Ebersole, Springfield,

Ohio I Assignee: Koehring Company, Milwaukee,

Wis.

Filed: Oct. 19, 1972 Appl. No.: 299,059

[75] Inventor:

US. Cl. 74/61, 198/220 DB, 74/87 Int. Cl. F1611 33/00 Field 011 Search. 74/61, 87, 573;

References Cited UNITED STATES PATENTS 9/1958 Nauta t. 74/61 June 4, 1974 Kahn 74/573 Carrier, Jr. I98/220 DB Primary ExaminerSamuel Scott Assistant Examiner-Wesley S. Ratliff, Jr. Attorney, Agent, or Firm Andrew J. Beck [5 7 ABSTRACT The present invention provides an apparatus for producing a variable amplitude vibratory force which is particularly useful as a rotatable eccentric for a vibratory roller. The rotatable eccentric comprises first and second eccentric fluid chambers rotatable about a common axis of rotation, and adjustable valve means 1 interconnecting the chambers for controlling the amount of fluid transfer between the chambers upon rotation .of the eccentric to produce a variable amplitude vibiatory force.

30 Claims, 7 Drawing Figures NENTEHJUN 4m: Q 331335 Sam 1 m d F/Q Z agelsgso PMENYEMH 4 1914 SHEU 3 (If Q l I APPARATUS FOR PRODUCING VARIABLE AMPLITUDE VIBRATORY FORCE The present invention relates to an apparatus for producing a variable amplitude vibratory force and, more particularly, to a rotatable eccentric for use in a vibratory roller to produce a variable amplitude vibratory force upon rotation.

In the art of vibratory rollers, it is well known to use a rotatable eccentric device mounted for rotation about the axis of a vibratory roller to impart a vibratory force to the roller. In the prior art, vibrating devices incorporating liquid filled eccentric weights have been.

weights. The manual arrangements have not been capable of precise and automatic control of the fluid transfer.

The present invention provides a rotatable eccentric for use in a vibratory roller to produce a variable amplitude vibratory force capable of precise adjustment. In contrast to the devices of the prior art, the rotatable eccentric requires no external control devices and operates automatically in response to centrifugal forces generated upon rotation of the eccentric.

In accordance with the present invention, a rotatable eccentric for producing a variable amplitude vibratory force upon rotation comprises first and second eccentric fluid chambers rotatable about a common axis of rotation, and adjustable valve means interconnecting the chambers for controlling the amount of fluid transfer between the chambers upon rotation of the eccentric to produce a variable amplitude vibratory force. In a preferred embodiment, the first chamber is a fluid reservoir comprising a hollow cylinder having closed ends with its axis displaced from the common axis of rotation, and the second chamber is mounted on the cylinder on the opposite side of the axis of rotation from the axis of the cylinder. Preferably, the adjustable valve means comprises an inlet member mounted at one end of the cylinder having an inlet orifice in fluid communication with the interior of the cylinder and capable of movement between various radial positions relative to the axis of rotation for receivingfluid upon rotation of the eccentric, and means for selectively moving the inlet member to adjust the inlet orifice be tween its various radial positions to control the amount of fluid transfer from the first chamber to the second chamber.

An alternative embodiment of the rotatable eccentric of the present invention includes a fluid reservoir chamber and an eccentric fluid chamber rotatable about a common axis of rotation, first adjustable valve means interconnecting the reservoir chamber and the eccentric chamber for controlling the amount of fluid transferred from the reservoir chamber to the eccentric chamber under the action of centrifugal forces generated upon rotation of the eccentric to produce a variable amplitude vibratory force, and second adjustable valve means interconnecting the reservoir chamber and the eccentric chamber for permitting a portion of the fluid transferred from the reservoir chamber to the eccentric chamber during rotation of the eccentric to return by gravity to the reservoir chamber upon termination of the rotation.

The rotatable eccentric of the present invention eliminates the requirement of an external control device for controlling fluid transfer. In addition, the eccentric permits an infinitely variable vibratory force to be obtained.

The accompanying drawings illustrate a preferred embodiment of the invention and, together with the description, serve to explain the principles of the invention.

In the drawings:

FIG. I is a longitudinal section of a vibratory roller illustrating a rotatable eccentric constructed in accordance with the principles of the present invention comprising a fluid reservoir, an eccentric fluid chamber, and adjustable valve means interconnecting the eccentric fluid chamber and reservoir.

FIG. 2 is a vertical section of the rotatable eccentric taken along line 22 of FIG. 1.

FIG. 3 is an end view of the vibratory roller of FIG. I.

.FIG. 4 is a sectional view of an alternative embodiment of the adjustable valve means of the rotatable eccentric of the present invention.

FIG. 5 is a vertical section, similar to FIG. 2, of the rotatable eccentric of FIG. 4 showing a front view of the adjustable valve means.

FIG. 6 is a front elevation, partially in section, illustrating another rotatable eccentric constructed in accordance with the principles of the present invention including a fluid reservoir chamber, an eccentric fluid chamber, and adjustable valve means in both the reservoir chamber and the eccentric chamber.

FIG. 7 is an end view of the rotatable eccentric of FIG. 6.

Referring to FIG. 1, a vibratory roller, generally 20, is mounted for rotation between a pair of transversely spaced

roller support arms

22 and 24 of a compacting device (not shown) by a pair of

bearing assemblies

26 and 28, respectively. A pair of

shaft portions

30 and 32 is rotatably supported by

bearing assemblies

26 and 28, respectively. The bearing assemblies include conventional bearing arrangements (not shown) to permit roller 20 to rotate relative to

roller support arms

22 and 24 and-to permit rotation of

shaft portions

30 and 32 relative to the roller. A pair of

rotatable counterweights

34 and 36 is mounted on

shaft portions

30 and 32, respectively, within

bearing assemblies

26 and 28.

Vibratory roller 20 comprises a pair of

circular end walls

38 and 40 and a cylindrical shell 42 mounted peripherally on

end walls

38 and 40 for compacting engagement with a surface S. End wall 38 is provided with a central circular opening 44 for receiving bearing assembly 26. Similarly, end wall 40 is provided with a central circular opening 46 for receiving bearing assembly 28. Vibratory roller 20 is thus mounted for rotation about its axis by bearing

assemblies

26 and 28. In addition, end wall 38 is provided with an opening 48 to allow easy access to the interior of vibratory roller 20.

As shown in FIG. I, a rotatable eccentric, generally 50, constructed in accordance with the-principles of the present invention, is mounted on shaft portions'3ll and 32 for rotation about the axis of vibratory roller 20. A fluid motor (not shown) is coupled to one of the shaft portions to impart rotation to the eccentric.

In accordance with the invention, the rotatable eccentric for producing a variable amplitude vibratory force comprises first and second eccentric fluid chambers rotatable about a common axis of rotation. In a preferred embodiment, the geometric axes of the chambers are located at diametrically opposed positions relative to the axis of rotation and are spaced at different distances from the axis of rotation. As embodied and shown in FIG. l, rotatable eccentric 55) includes a first fluid chamber 54 comprising a hollow cylinder 56 provided with

circular end plates

58 and 60 to close the ends of the cylinder. A sleeve @2 is mounted on end plate 58 at a position displaced from the axis of the cylinder and is coupled to shaft portion 30 by a pair of pins 6 3. .Similarly, a sleeve as is mounted on end plate 60 in axial alignment with sleeve 62 and is coupled to shaft portion 32 by a pair of pins 68.

Rotatable eccentric 50 also includes a second fluid chamber 70 comprising a generally rectangular housing 72 and

rectangular end walls

74 and 76. As shown in FIGS. l and 2, rectangular housing 72 and

end walls

74 and 76 are mounted in fluid-tight engagement on the outer surface of cylinder 56 at a position diametrically opposed to the axis of cylinder 56 in relation to the roller axis. Chamber 54 acts as a fluid reservoir to supply fluid'to eccentric chamber 70.

In accordance with the invention, the rotatable eccentric includes adjustable valve means interconnecting the chambers for controlling the amount of fluid transfer between the chambers upon rotation of the eccentric to produce a variable amplitude vibratory force. As illustrated in the embodiment shown in FIG. l, a control valve, generally 80, is mounted on end plate 58 of cylinder 56. The control valve includes an inlet member in the form of a tube 82 rotatably mounted in a passage provided in a valve block 34 secured to end plate 58. Inlet tube $2 extends into cylinder 56 through a passage provided in end plate 58. The inlet tube includes a bent portion 86 provided with an inlet orifice 88 capable of movement between various radial positions within cylinder 56 relative to the axis of rotation. A handle 90 is coupled to the opposite end of tube '82 to enable the tube to be selectively rotated. Handle 90 thus provides means for selectively moving the inlet member, i.e., rotatable tube 82, to adjust inlet orifice 88 between its various radial positions.

As shown in FIG. 1, valve block 84 includes a passageway 92 extending from the passage in the valve block for receiving inlet tube 82 to the lower end of the valve block. Tube 82 is provided with an opening (not shown) in fluid communication with passageway 92 to permit fluid admitted to tube 82 through inlet orifice 88 to flow into the passageway.

Conduit means for coupling the adjustable valve means to the second fluid chamber is embodied as a conduit 94 extendingfrom the lower end of valve block 8 3 to a fluid inlet as provided in housing '72 of eccentric fluid chamber 70. Conduit 94 permits fluid transfer from reservoir chamber t through inlet tube 82, passageway 92 and fluid inlet 96 to eccentric fluid chamber 70. An air vent in the form of a tube 97 extending through the side wall of cylinder 56 is provided to permit air located within reservoir chamber 54 and eccentric chamber to be displaced between the chambers upon fluid transferto equalize the pressures in the chambers.

A baffle plate 98 (FIGS. 1 and 2) is mounted within reservoir chamber 54. The baffle plate extends radially inward from the lower portion of the side wall of cylinder 56. A plurality of struts 99 (FIG. -1) is provided to maintain baffle plate 98 in a rigid position within the cylinder. The purpose of the baffle plate is to restrict fluid movement in the reservoir chamber during rotation of eccentric 50. As shown in FIG. 1, baffle plate 9% includes a plurality of spaced openings 100 formed in its lower edge to allow limited flow to opposite sides of the baffle plate.

In a preferred embodiment of the rotatable eccentric, conduit means is provided for coupling the first and second chambers to permit fluid transferred from the first chamber to the second chamber during rotation of the eccentric to drain into the first chamber upon termination of the rotation. As shown in FIGS. 1 and 2, this conduit means is embodied in rotatable eccentric 50 as a pair of

ball check valves

101 and 102 mounted in openings formed in cylinder 56 at the lower end of chamber 70. Referring to FIG. 2, ball check valve 101 comprises a hollow cylindrical body 104 having an opening 105 of reduced size at its upper end to provide a valve seat. A ball 106 is located within hollow cylindrical body 104, and a pin 107 extends across the hollow cylindrical body at its lower end. Upon rotation of eccentric 50, ball 106 is driven by centrifugal force into contact with the valve seat to prevent fluid flow from eccentric chamber 70 to reservoir chamber 54. When rotation of the eccentric is terminated, ball 106 drops into a rest position in contact with pin 107 to permit fluid transferred to eccentric chamber 70 to drain into reservoir chamber 54. Ball check valve 102 is identical in structure and operation to ball check valve 101.

In operation of the rotatable eccentric of FIG. 1, a predetermined amount of fluid is supplied to reservoir chamber 54. Control valve is then operated by rotating handle to position inlet orifice 88 of rotatable tube 82 in a desired radial position relative to the axis of rotation. Upon operation of the fluid motor (not shown), rotatable eccentric 50 is rotated about the axis of the vibratory roller. The rotation of eccentric 50 causes the fluid in reservoir chamber 54 to adopt a generally annular configuration (indicated by shaded region 108 in FIG. 2) about the axis of rotation of chamber 54 as a result of centrifugal forces exerted on the fluid. The fluid located in region 108 flows through inlet orifice 88 of tube 82, passageway 92, conduit 94, and inlet opening 926 into eccentric chamber 70 until, as shown in FIG. 2, the inner radius of the fluid in annular region l08 coincides with the radial distance of inlet orifice 88 from the axis of rotation. This radial distance can be selectively varied by rotation of handle 90 to move inlet orifice 88 of tube 82 to different radial positions within reservoir chamber 54 to thereby control the amount of fluid transferred from the reservoir chamber to eccentric chamber 70.

The fluid transferred to eccentric chamber 70 also adopts a generally annular configuration (indicated by shaded region ill) in FIG. 2). This fluid constitutes an eccentric weight that is rotated about the axis of vibratory roller 20. Thus, upon rotation of eccentric 50 about the axis of roller 21), a vibratory force is imparted to the roller having an amplitude determined by the amount of fluid transferred to eccentric chamber 78 and the magnitude of

counterweights

34 and 36. The amplitude of the vibratory force produced by eccentric 50 can be precisely adjusted by rotating handle 90 of control valve 80 to change the position of inlet orifice 88 of tube 82 in reservoir chamber 54 to vary the amount of fluid transferred to eccentric chamber 70. Thus, the amplitude of the total vibratory force imparted to roller 211 can be increased or decreased by adjustment of the control valve.

In the embodiment of the rotatable eccentric of FIGS. 4 and 5, an alternative arrangement is provided for securing sleeve 62 to cylinder 56. Referring to F110 4, a circular opening 118 is formed in end plate 58 of cylinder 56 at a position spaced from the common axis of the cylinder and end plate. Sleeve 62 extends through opening 118 and is secured to end plate 58 in a conventional manner, such as by welding. A similar arrangement (not shown) is provided at the opposite end of cylinder 56 for securing sleeve 66 (FIG. 2) to the cylinder.

In addition, the rotatable eccentric of FIGS. 4, and 5 incorporates an alternative embodiment of the adjustable valve means of the present invention. Referring to FIG. 4, a control valve, generally 128, is mounted on end plate 58 of cylinder 56. The end plate is provided with a circular opening 122 for receiving a generally circular valve block 124 of the control valve. The valve block is provided with a peripheral groove for mounting an O-ring seal 125 in sealing engagement with the side wall of circular opening 122. In addition, valve block 124 is provided with an axial passage 126 for rotatably receiving a shaft 128. Shaft 128 includes a pcripheral groove for mounting an O-ring seal 130 in sealing engagement with the interior wall of passage 126.

Control valve 120 includes an inlet member in the form of a disc 132 (FIGS. 4 and 5) provided with an inlet orifice 134 extending completely through the disc at a position spaced radially from the disc axis. Valve block 124 is provided with a cylindrical recess 136 formed on its front surface for receiving disc 132. The disc is supported on the inner end of shaft 128 for rotation in cylindrical recess 136. Disc 132 includes a pcripheral groove formed along its outer surface for mounting an O-ring seal 138 in sealing engagement with the interior cylindrical wall of recess 136.

As shown in FIG. 4, the outer end of shaft 128 comprises a sleeve 140 including a pair of circular openings 142 formed at diametrically opposed positions adjacent to the end of the sleeve. A lock nut 144 is provided to maintain shaft 128 within passage 126 of valve block 124. Shaft 128 is provided with an axial bore for receiving a bolt 146 to secure disc 132 to the opposite, inner end of shaft 128. Referring to FIG. 5, a handle 148 is fitted in openings 142 of sleeve 1411 to provide means for selectively moving the inlet member, i.e., rotatable disc 132, to adjust inlet orifice 134 between various radial positions relative to the axis of rotation.

Valve block 124 (FIG. 4) includes a first passageway 150 extending axially from recess 136 and a second passageway 152 extending radially from passageway 150 to the lower end of the valve block.

Passageways

150 and 152 receive fluid admitted into recess 136 through inlet orifice 134 of disc 132.

Conduit means for-coupling the adjustable valve means to the second fluid chamber is embodied as a conduit 154 extending from the lower end of valve block 124 to a fluid inlet 156-(FIG. 5) provided in the housing of eccentric fluid chamber 70. Conduit 154 permits fluid transfer from reservoir chamber 54 through orifice 134 of rotatable disc 132, recess 136, passageways 1511 and 152, and fluid inlet 156 to the eccentric fluid chamber. As shown in FIG. '5, the rotatable eccentric includes a pair of ball check valves 101 and 1112 identical in structure and operation to the ball check valves of the rotatable eccentric of FIG. 2.

The operation of the rotatable eccentric of FIGS. 4 and 5 is substantially the same as the operation of the rotatable eccentric of FIGS. 1 and 2 previously described. Initially, a predetermined amount of fluid is supplied to reservoir chamber 54. Control valve is then operated by rotating handle 148 to position inlet orifice 134 of rotatable disc 132 in a desired radial position relative to the axis of rotation.

When the eccentric is rotated, the fluid in reservoir chamber 54 adopt a generally annular configuration (indicated by shaded region 158 in FIG. 5) about the axis of rotation of reservoir chamber 54 as a result of centrifugal forces exerted on the fluid. The fluid located in region 158 flows through inlet orifice 134 of disc 132, recess 136 and passageways and 152 in valve block 124, conduit 154, and fluid inlet 156 into eccentric chamber 70 until, as shown in FIG. 5, the inner radius of the fluid in annular region 158 coincides with the radial distance of inlet orifice 134 from the axis of rotation. This radial distance can be selectively varied by rotation of handle 148 to move inlet orifice 134 to different radial positions within reservoir chamber 54 to thereby control the amount of fluid transferred from the reservoir chamber to eccentric chamber 70. i

The fluid transferred to eccentric chamber 70 also adopts a generally annular configuration (indicated by shaded region 160 in FIG. 5). This fluid constitutes an eccentric weight that produces vibratory forces as a result of rotation of the eccentric. The amplitude of the vibratory force produced by the eccentric can be precisely adjusted by rotating handle 148 of control valve 120 to change the position of inlet orifice 134 of disc 132 in reservoir chamber 54 to vary the amount of fluid transferred to eccentric chamber 70. Thus, control valve 121) permits the amplitude of the vibratory forces generated by the eccentric to be selectively increased or decreased as desired.

FIGS. 6 and 7 illustrate an alternative embodiment of the rotatable eccentric of the present invention including a fluid reservoir chamber and an eccentric fluid chamber rotatable about a common axis of rotation, and adjustable valve means located in both the reservoir chamber and the eccentric chamber. Referring to FIG. 6, fluid reservoir chamber 54 and eccentric fluid chamber 70 are identified by the same reference numerals used in the discussion of the previous embodiments. Reservoir chamber 54 is provided by cylinder 56 having

end plates

58 and 60 secured at its opposite ends.

Sleeves

62 and 66 are mounted on end plates 58 and 611, respectively, at positions displaced from the axis of cylinder 56 to support the eccentric for rotation about the axis of a vibratory roller (not shown). Eccentric fluid chamber 70 is provided by a generally rectangular housing 72 including

end plates

74 and 76. The

eccentric chamber is mounted on cylinder 56 on the opposite side of the axis of rotation from the axis of the cylinder.

An air vent in the form of a tube 97 mounted in opening formed in cylinder 56 is provided for interconnecting reservoir chamber 54 and eccentric chamber 70 to allow air displacement between the reservoir and eccentric chambers. In addition, a baffle plate 98 is mounted within reservoir chamber 54. The baffle plate extends radially inward from the lower portion of the side wall of cylinder 56, and a plurality of struts 99 is provided to maintain the baffle plate in a rigid position in the cylinder. The purpose of baffle plate 98 is to restrict fluid movement in cylinder 56 during rotation of the eccentric. Baffle plate 98 includes a plurality of spaced openings 190 formed in its lower edge to allow limited fluid flow to opposite sides of the baffle plate.

In 'accordance with the invention, the eccentric includes first adjustable valve means interconnecting the reservoir chamber and the eccentric chamber for controlling the amount of fluid transferred from the reservoir chamber to the eccentric chamber under the action of centrifugal forces generated upon rotation of the eccentric to produce a variable amplitude vibratory force. The first adjustable valve means is embodied in the rotatable eccentric of FIG. 6 as a first control valve, generally 181), substantially identical to control valve 120 of FIG. 4. Control valve 180 (FIG. 6) includes an inlet member in the form ofa rotatable disc 182 having an inlet orifice 184 in fluid communication with reser voir chamber54. Inlet orifice 184 extends completely through rotatable disc 182 at a position spaced radially from the axis of the disc.

Disc 182 is received in a recess 186 formed in a valve block 188 mounted in an opening provided in end plate 58. A shaft 190 is rotatably received in an axial passage formed in valve block 188. A gear wheel 192 is secured to the outer end of shaft 190, and disc 182 is supported on the opposite end of the shaft for rotation in recess 186. A first passageway 194 extends axially from recess 186 into valve block 188, and a second passageway 196 extends radially from passageway 194 to the lower end of the valve block.

First conduit means for coupling the first adjustable valve means to the eccentric chamber is embodied as a conduit 198 extending from the lower end of valve block 188 to a fluid inlet 2011 provided in housing 72 of eccentric chamber 70. Conduit 198 permits fluid to be transferred from reservoir chamber 54 through orifice 184 of disc 182, recess 186,

passageways

194 and 196, and fluid inlet 200 to the eccentric chamber.

In accordance with the invention, the rotatable eccentric includes second adjustable valve means interconnecting the reservoir chamber and the eccentric chamber for permitting a portion of the fluid transferred from the reservoir chamber to the eccentric chamber during rotation of the eccentric to return by gravity to the reservoir chamber upon termination of the rotation. As embodied in FIG. 6, a second control valve, generally 210, similar to control valve 180, is provided in eccentric fluid chamber 711. Control valve 210 includes an inlet member in the form ofa rotatable disc 212 having an inlet orifice 214 in fluid communication with eccentr'ic fluid chamber 70. Inlet orifice 214 extends completely through disc 212 at a position spaced radially from the axis of the disc.

Disc 212 is received in a recess 216 formed in a valve block 218 mounted in an opening provided in end wall 74. A sleeve 222 (FIG. 6) extends outward from valve.

block 218, and a shaft 224 is rotatably received within sleeve 222 and an axial passage provided in the valve block. A gear wheel 226 is secured to the outer end of shaft 224 and disc 212 is supported on the opposite end of the shaft for rotation in recess 216. Gear wheel 226 of control valve 210 is located in vertical alignment with gear wheel 192 of control valve 180.

Second conduit means for coupling the second adjustable valve means to the interior of the cylinder is embodied as tube 220 extending downward from recess 216 into reservoir chamber 54 through openings provided in valve block 218 and cylinder 56. Tube 220 allows fluid received by recess 216 through inlet orifice 214 of disc 212 to return by gravity to cylinder 56.

As shown in FIG. 6, adial 228 is mounted on shaft 224 for rotation with the shaft and gear wheel 226. The dial is provided with markers (not shown) for indicating the position of inlet orifice 214 in eccentric chamber 70. A pointer 230 is mounted on sleeve 222 and extends across the top of dial 228 to allow adjustment of control valve 210 to set its inlet orifice to a desired position by rotating dial 228 to align the corresponding marker on the dial with the pointer.

A chain 232 (FIGS. 6 and 7) is provided for

coupling gear wheels

192 and 226 to rotate the gear wheels simultaneously upon rotation of dial 228. .As shown in FIG. 7,

control valves

180 and 210 are arranged to position inlet orifice 214 of rotatable disc 212 in its lowermost position in eccentric chamber when inlet orifree 184 of disc 182 is located in its uppermost position in reservoir chamber 54. On the other hand, when inlet orifice 214 of rotatable disc 212 is located in its uppermost position in eccentric chamber 70, inlet orifice 184 of disc 182 is located in its lowermost position in the reservoir chamber. In addition, by rotation of dial 228,

inlet orifices

184 and 214 can be simultaneously adjusted to an infinite number of intermediate positions.

In the operation of the rotatable eccentric of FIGS. 6 and 7, a predetermined amount of fluid is supplied to reservoir chamber 54. Control valves and 210 are then simultaneously operated by rotating dial 228 to position

inlet orifices

184 and 214 of

rotatable discs

182 and 212, respectively, in desired radial positions relative to the axis of rotation. When the eccentric is rotated, the fluid in reservoir chamber 54 adopts a generally annular configuration about the axis .of rotation as the result of centrifugal forces exerted on the fluid. The fluid located in the reservoir chamber. flows through inlet orifice 184 of disc 182, recess 186 and

passageways

194 and 196 in valve block 188, conduit 198 and fluid inlet 200 until the inner radius of the fluid in the annular region in reservoir chamber 54 coincides with the radial distance of inlet orifice 184 from the axis of rotation. This radial distance can be selectively varied by rotation of dial 228 to move inlet orifice 184 to difierent radial positions within reservoir chamber 54 to control the amount of fluid transferred from the reservoir chamber to eccentric chamber 70.

The fluid transferred to eccentric chamber 70 also adopts a generally annular configuration during rotation of the eccentric. This fluid constitutes an eccentric weight that produces vibratory forces as a result of rotation of the eccentric. The amplitude of the vibratory force produced by the eccentric can be precisely adjusted by rotating dial 228 to change the position of inlet orifice H84 in reservoir chamber 541 to vary the amount of fluid transferred to eccentric chamber 70. Thus, by adjustment of control valve 210 to move inlet orifice 184 between its various radial positions, the amplitude of the vibratory force produced upon rotation of the eccentric can be increased or decreased as desired.

When rotation of the eccentric is terminated, the amount of fluid. that returns from eccentric chamber 70 to reservoir chamber 54 is determined by setting of control valve 210. When, as shown in FIG. 7, inlet orifice 214 of control valve 210 is located in its lowermost position, all of the fluid transferred from reservoir chamber 54 to eccentric chamber 70 through control valve 180 during rotation of the eccentric will return by gravity to the reservoir chamber. When inlet orifice 214 of control valve 210 is located in any other position, however, only a portion of the fluid transferred from reservoir chamber 54 to eccentric chamber 70 will return by gravity through control valve 210 to the reservoir chamber. Thus, an amount of fluid determined by the setting of valve 210 will remain in eccentric chamber 70 even though rotation of the eccentric is completely terminated. Thereafter, when rotation of the eccentric is resumed, the fluid returned to reservoir chamber 54 from eccentric chamber 70 will again be transferred to the eccentric chamber through control valve 180 to produce vibratory forces of a desired amplitude.

By preventing all of the fluid transferred to eccentric chamber 70 during rotation of the eccentric from returning to reservoir chamber 54 when the eccentric is temporarily stopped, the embodiments of FIGS. 6 and 7 permits the amplitude of the vibratory forces produced by the eccentric to be stabilized at a desired level. This embodiment thus allows a repeated start and stop operation of the eccentric with a minimum amount of fluid flow between the eccentric chamber to the reservoir chamber.

The invention in its broader aspects is not limited to the specific details shown and described, and modifications may be made in the details of the rotatable eccentric without departing from the principles of the present invention.

What is claimed is:

1. A compacting device, comprising:

a support;

a roller rotatably mounted on said support; and

a rotatable eccentric mounted within said roller for rotation about the roller axis independently of said roller to produce a variable amplitude vibratory force upon rotation, said eccentric comprising first and second fluid chambers each eccentrically rotatable about the roller axis independently of rotation of said roller and adjustable valve means interconnecting said chambers for controlling the amount of. fluid transfer between said chambers upon rotation of said eccentric to produce a variable amplitude vibratory force.

2. The compacting device of claim 1, wherein the geometric axes of said chambers are located at diametrically opposed positions relative to the roller axis and spaced at different distances from the roller axis. 3. The compacting device of claim 1, wherein:

said first chamber comprises a hollow cylinder having closed ends with its axis displaced from the roller axis; and

said second chamber is mounted on said cylinder on the opposite side of the roller axis from the axis of said cylinder.

4. The compacting device of claim 3, wherein said adjustable valve means comprises:

an inlet member mounted at one end of said cylinder having an inlet orifice in fluid communication with the interior of said cylinder and capable of movement between various radial positions relative to the roller axis for receiving fluid from said cylinder upon rotation of the eccentric; and

means for selectively moving said inlet member to adjust said inlet orifice between its various radial positions to control the amount of fluid transfer from said first chamber to said second chamber.

5. The compacting device of claim 4, wherein:

said inlet member of said adjustable valve means comprises a tube rotatably mounted in an opening formed at one end of said cylinder, said tube including a bent portion at one of its ends extending into said cylinder to provide said inlet orifice; and which includes conduit means for coupling said adjustable valve means to said second fluid chamber to permit fluid received from said first chamber through said inlet orifice to be transferred to said second chamber upon rotation of said eccentric.

6. The compacting device of claim 5, wherein:

said means for moving said inlet member comprises a handle connected to the opposite end of said tube for rotating the bent portion of said tube to various radial positions.

7. The compacting device of claim 4, wherein:

said inlet member of said adjustable valve means comprises a disc rotatably mounted in an opening formed at one end of said cylinder, said inlet orifice extending completely through said disc at a position spaced radially from the axis of said disc; and which includes conduit means for coupling said adjustable valve means to said second fluid chamber to permit fluid received from said first chamber through said inlet orifice to be transferred to said second, chamber upon rotation of said eccentric.

8. The compacting device of claim 4, wherein:

said adjustable valve means includes a valve block mounted in an opening formed at one end of said cylinder, said valve block including a recess formed on its front surface in fluid communication with the interior of said cylinder;

said inlet member comprises a disc rotatably mounted in said recess formed in said valve block, said inlet orifice extending completely through said disc at a position spaced radially from the axis of said disc; and which includes conduit means for coupling said adjustable valve means to said second fluid chamber to permit fluid admitted into said recess in said valve block through said inlet orifice to be transferred to said second chamber upon rotation of said eccentric.

9. The compacting device of claim 1, which includes:

conduit means for coupling said first and second chambers to permit fluid transferred from said first ill chamber to said second chamber during rotation of said eccentric to drain into said first chamber upon termination of the rotation. 10. The compacting device of claim 1, which includes:

an air vent for interconnecting said first and second chambers to permit air located within said chambers to be displaced between said chambers during fluid transfer upon rotation of said eccentric. ill. The compacting device of claim 3, which includes:

a baffle plate extending radially inward from the interior of said cylinder for restricting fluid movement in said cylinder during rotation of eccentric.

12. A compacting device, comprising:

a support;

a vibratory roller mounted on said support for rotation about its axis; and

a rotatable eccentric mounted within said roller for rotation about the roller axis independently of said roller to produce-a variable amplitude vibratory force, said rotatable eccentric comprising an eccentric fluid chamber rotatable about the roller axis for producing a vibratory force upon rotation;

a fluid reservoir rotatable about the roller axis for supplying fluid to said eccentric fluid chamber under the action of centrifugal forces generated upon rotation of said reservoir; and

adjustable valve means interconnecting said eccentric fluid chamber and said reservoir for controlling the amount of fluid transfer from said reservoir to said eccentric fluid chamber as a result of the centrifugal forces to permit the amplitude of the vibratory force to be adjusted. I

13. The compacting device of claim 12, wherein said adjustable valve means of said rotatable eccentric comprises:

an inlet member having an inlet orifice in fluid communication with said reservoir and capable of movement between-various radial positions relative to the roller axis for receiving fluid under the action of the centrifugal forces generated upon rotation of said reservoir; and

means for selectively moving said inlet member to adjust said inlet orifice between its various radial positions to control the amount of fluid transfer from said reservoir to said eccentric fluid chamber.

14. The compacting device of claim 13, wherein said rotatable eccentric includes:

conduit means for coupling said adjustable valve means to said eccentric fluid chamber to permit fluid transfer through said inlet member from said reservoir to said eccentric chamber.

15. The compacting device of claim 13, wherein:

said inlet member of said adjustable valve means comprises a tube rotatably mounted in an opening formed at one end of said fluid reservoir, said tube including a bent portion at one of its ends extending into said fluid reservoir to provide said inlet orifree; and

6 conduit means for coupling said ad ustable valve means to said eccentric fluid chamber to permit fluid received from said fluid reservoir through said inlet orifice to be transferred to said eccentric fluid chamber upon rotation of said eccentric.

16. The compacting device of claim 15, wherein:

said means for selectively moving said inlet member comprises a handle connected to the opposite end of said tube for rotating the bent portion of said tube to various-radial positions in said fluid reservoir; and

said vibratory roller'includes an opening formed in one of its sides to allow access to said handle.

17. The compacting device of claim 13, wherein:

said inlet member of said adjustable valve means comprises a disc rotatably mounted in an opening formed at one end of said fluid reservoir, said inlet orifice extending completely through said disc at a position spaced radially from the axis of said disc; and which includes conduit means for coupling said adjustable valve means to said eccentric fluid chamber to permit fluid received from said fluid reservoir through said inlet orifice to be transferred to said eccentric fluid chamber upon rotation of said eccentric.

18. The compacting device of claim 12, wherein said rotatable eccentric includes:

conduit means for coupling said eccentric fluid chamber to said reservoir to permit fluid transferred from said reservoir to said chamber during rotation of said eccentric to drain into said reservoir upon termination of the rotation.

19. The compacting device of claim 12, wherein: said fluid reservoir comprises a cylindrical chamber having its axis displaced from the roller axis; and said eccentric fluid chamber is mounted on said cylindrical chamber at a position diametrically opposed to the axis of said cylindrical chamber in relation to the roller axis. 20. The compacting device of claim 12, which includes:

counterweight means mounted for rotation with said eccentric about the axis of the vibratory roller. 21. A rotatable eccentric for producing a variable amplitude vibratory force upon rotation, comprising:

a fluid reservoir chamber and an eccentric fluid chamber rotatable about a common axis of rotation;

first adjustable valve means interconnecting said reservoir chamber and said eccentric chamber for controlling the amount of fluid transferred from said reservoir chamber to said eccentric chamber under the action of centrifugal forces generated upon rotation of the eccentric to produce a variable amplitude vibratory force; and

second adjustable'valve means interconnecting said reservoir chamber and said eccentric chamber for permitting a portion of the fluid transferred from said reservoir chamber to said eccentric chamber during rotation of the eccentric to return by gravity to said reservoir chamber upon termination of the rotation.

22. The rotatable eccentric of claim 21, wherein the geometric axes of said fluid reservoir chamber and said eccentric chamber are located at diametrically opposed positions relative to the axis of rotation and spaced at different distances from the axis of rotation.

23. The rotatable eccentric of claim 21, wherein:

said fluid reservoir chamber comprises a hollow cylinder having closed ends with its axis displaced from the common axis of rotation; and

said eccentric chamber is mounted on said cylinder on the opposite side of the axis of rotation from the axis of said cylinder.

24. The rotatable eccentric of claim 21, wherein:

said first adjustable valve means includes a first inlet member having an inlet orifice in fluid communication with said fluid reservoir chamber and capable of movement between various radial positions in said fluid reservoir chamber relative to the axis of rotation for receiving fluid from said fluid reservoir chamber upon rotation of the eccentric; and

said second adjustable valve means includes a second inlet member having an inlet orifice in fluid communication with said eccentric chamber and capable of movement between various radial positions in said eccentric chamber relative to the axis of rotation for receiving fluid from said eccentric chamber upon termination of rotation of the eccentric; and which includes first conduit means for coupling said first adjustable valve means to said eccentric chamber to permit fluid received by said first inlet member to be transferred to eccentric chamber; and

second conduit means for coupling said second adjustable valve means to said fluid reservoir chamber to permit fluid received by said second inlet member to be returned by gravity to said fluid reservoir chamber.

25. The rotatable eccentric of claim 23, wherein:

said first adjustable valve means includes a first valve block mounted in an opening formed at one end of said cylinder, said first valve block including a recess formed on its front surface in fluid communication with the interior of said cylinder, and a first disc rotatably mounted in said recess formed in said first valve block having a first inlet orifice extending completely through said first disc at a posi tion spaced radially from the axis of said first disc; and

said second adjustable valve means comprises a second valve block mounted in an opening formed at one end of said eccentric chamber, said second valve block including a recess formed on its front surface in fluid communication with the interior of said eccentric chamber, and a second disc rotatably mounted in said recess formed in said second valve block having a second inlet orifice extending completely through said second disc at a position spaced radially from the axis of said second disc; and which includes conduit means for coupling said first adjustable'valve means to said eccentric chamber to permit fluid admitted into said recess in said first valve block through said first inlet orificeto be transferred to said eccentric chamber upon rotation of the eccentric; and

second conduit means for coupling said second adjustable valve means to the interior of said cylinder to permit fluid admitted into said recess in said second valve block through said second inlet orifice to be transferred to said cylinder upon termination of the rotation of the eccentric.

26. The rotatable eccentric of claim 25, which includes:

means for simultaneously rotating said first and second discs to adjust said first and second inlet orifices to desired radial positions.

27. The rotatable eccentric of claim 26, wherein:

said first adjustable valve means includes a shaft rotatably received in a passage extending through said first valve block for supporting said first disc for rotation in said recess formed in said first valve block;

said second adjustment valve means includes a second shaft rotatably received in a passage extending through said second valve block for supporting said second disc for rotation in said recess formed in said second valve block; and

said means for simultaneously rotating said first and second discs includes a first gear wheel secured to said first shaft, a second gear wheel secured to said second shaft, and a chain for connecting said first and second gear wheels for simultaneous rotation.

28.The rotatable eccentric of claim 23, which includes:

a bafile plate extending radiallydnward from the interior of said cylinder for restricting fluid movement in said cylinder during rotation of the eccentric. 29. A compacting device, comprising: a support; a roller rotatably mounted on said support; and a rotatable eccentric mounted within said roller for rotation about the roller axis independently of said roller to produce a variable amplitude vibratory force upon rotation, said eccentric comprising first and second fluid chambers eccentrically rotatable about the roller axis independently of rotation of said roller; and

fluid conduit means interconnecting said chambers, said fluid conduit means including an inlet member located in said first chamber and movable between various positions in said first chamber for controlling the amount of fluid transfer from said first chamber to said second chamber upon rotation of said eccentric to produce a variable amplitude vibratory force.

30. A compacting device, comprising:

a support;

a vibratory roller mounted on said support for rotation about its axis;

a rotatable eccentric mounted within said roller for rotation about the roller axis independently of the roller to produce a variable amplitude force, said rotatable eccentric comprising an eccentric fluid chamber rotatable about the roller axis for producing a vibratory force upon rotation;

a fluid reservoir'rotatable about the roller axis for supplying fluid to said eccentric fluid chamber under the action of centrifugal forces generated upon rotation of said reservoir; and

fluid conduit means interconnecting said eccentric fluid chamber and said reservoir, said fluid conduit means including an inlet member located in said reservoir and movable between various positions in said reservoir for controlling the amount of fluid transfer from said reservoir to said eccentric fluid chamber as a result of the centrifugal forces to permit the amplitude of the vibratory force to be adjusted.

Claims

1. A compacting device, comprising: a support; a roller rotatably mounted on said support; and a rotatable eccentric mounted within said roller for rotation about the roller axis independently of said roller to produce a variable amplitude vibratory force upon rotation, said eccentric comprising first and second fluid chambers each eccentrically rotatable about the roller axis independently of rotation of said roller and adjustable valve means interconnecting said chambers for controlling the amount of fluid transfer between said chambers upon rotation of said eccentric to produce a variable amplitude vibratory force.

2. The compacting device of claim 1, wherein the geometric axes of said chambers are located at diametrically opposed positions relative to the roller axis and spaced at different distances from the roller axis.

3. The compacting device of claiM 1, wherein: said first chamber comprises a hollow cylinder having closed ends with its axis displaced from the roller axis; and said second chamber is mounted on said cylinder on the opposite side of the roller axis from the axis of said cylinder.

4. The compacting device of claim 3, wherein said adjustable valve means comprises: an inlet member mounted at one end of said cylinder having an inlet orifice in fluid communication with the interior of said cylinder and capable of movement between various radial positions relative to the roller axis for receiving fluid from said cylinder upon rotation of the eccentric; and means for selectively moving said inlet member to adjust said inlet orifice between its various radial positions to control the amount of fluid transfer from said first chamber to said second chamber.

5. The compacting device of claim 4, wherein: said inlet member of said adjustable valve means comprises a tube rotatably mounted in an opening formed at one end of said cylinder, said tube including a bent portion at one of its ends extending into said cylinder to provide said inlet orifice; and which includes conduit means for coupling said adjustable valve means to said second fluid chamber to permit fluid received from said first chamber through said inlet orifice to be transferred to said second chamber upon rotation of said eccentric.

6. The compacting device of claim 5, wherein: said means for moving said inlet member comprises a handle connected to the opposite end of said tube for rotating the bent portion of said tube to various radial positions.

7. The compacting device of claim 4, wherein: said inlet member of said adjustable valve means comprises a disc rotatably mounted in an opening formed at one end of said cylinder, said inlet orifice extending completely through said disc at a position spaced radially from the axis of said disc; and which includes conduit means for coupling said adjustable valve means to said second fluid chamber to permit fluid received from said first chamber through said inlet orifice to be transferred to said second chamber upon rotation of said eccentric.

8. The compacting device of claim 4, wherein: said adjustable valve means includes a valve block mounted in an opening formed at one end of said cylinder, said valve block including a recess formed on its front surface in fluid communication with the interior of said cylinder; said inlet member comprises a disc rotatably mounted in said recess formed in said valve block, said inlet orifice extending completely through said disc at a position spaced radially from the axis of said disc; and which includes conduit means for coupling said adjustable valve means to said second fluid chamber to permit fluid admitted into said recess in said valve block through said inlet orifice to be transferred to said second chamber upon rotation of said eccentric.

9. The compacting device of claim 1, which includes: conduit means for coupling said first and second chambers to permit fluid transferred from said first chamber to said second chamber during rotation of said eccentric to drain into said first chamber upon termination of the rotation.

10. The compacting device of claim 1, which includes: an air vent for interconnecting said first and second chambers to permit air located within said chambers to be displaced between said chambers during fluid transfer upon rotation of said eccentric.

11. The compacting device of claim 3, which includes: a baffle plate extending radially inward from the interior of said cylinder for restricting fluid movement in said cylinder during rotation of eccentric.

12. A compacting device, comprising: a support; a vibratory roller mounted on said support for rotation about its axis; and a rotatable eccentric mounted within said roller for rotation about the roller axis independently of said roller to produce a variable amplitude vibratory forcE, said rotatable eccentric comprising an eccentric fluid chamber rotatable about the roller axis for producing a vibratory force upon rotation; a fluid reservoir rotatable about the roller axis for supplying fluid to said eccentric fluid chamber under the action of centrifugal forces generated upon rotation of said reservoir; and adjustable valve means interconnecting said eccentric fluid chamber and said reservoir for controlling the amount of fluid transfer from said reservoir to said eccentric fluid chamber as a result of the centrifugal forces to permit the amplitude of the vibratory force to be adjusted.

13. The compacting device of claim 12, wherein said adjustable valve means of said rotatable eccentric comprises: an inlet member having an inlet orifice in fluid communication with said reservoir and capable of movement between various radial positions relative to the roller axis for receiving fluid under the action of the centrifugal forces generated upon rotation of said reservoir; and means for selectively moving said inlet member to adjust said inlet orifice between its various radial positions to control the amount of fluid transfer from said reservoir to said eccentric fluid chamber.

14. The compacting device of claim 13, wherein said rotatable eccentric includes: conduit means for coupling said adjustable valve means to said eccentric fluid chamber to permit fluid transfer through said inlet member from said reservoir to said eccentric chamber.

15. The compacting device of claim 13, wherein: said inlet member of said adjustable valve means comprises a tube rotatably mounted in an opening formed at one end of said fluid reservoir, said tube including a bent portion at one of its ends extending into said fluid reservoir to provide said inlet orifice; and conduit means for coupling said adjustable valve means to said eccentric fluid chamber to permit fluid received from said fluid reservoir through said inlet orifice to be transferred to said eccentric fluid chamber upon rotation of said eccentric.

16. The compacting device of claim 15, wherein: said means for selectively moving said inlet member comprises a handle connected to the opposite end of said tube for rotating the bent portion of said tube to various radial positions in said fluid reservoir; and said vibratory roller includes an opening formed in one of its sides to allow access to said handle.

17. The compacting device of claim 13, wherein: said inlet member of said adjustable valve means comprises a disc rotatably mounted in an opening formed at one end of said fluid reservoir, said inlet orifice extending completely through said disc at a position spaced radially from the axis of said disc; and which includes conduit means for coupling said adjustable valve means to said eccentric fluid chamber to permit fluid received from said fluid reservoir through said inlet orifice to be transferred to said eccentric fluid chamber upon rotation of said eccentric.

18. The compacting device of claim 12, wherein said rotatable eccentric includes: conduit means for coupling said eccentric fluid chamber to said reservoir to permit fluid transferred from said reservoir to said chamber during rotation of said eccentric to drain into said reservoir upon termination of the rotation.

19. The compacting device of claim 12, wherein: said fluid reservoir comprises a cylindrical chamber having its axis displaced from the roller axis; and said eccentric fluid chamber is mounted on said cylindrical chamber at a position diametrically opposed to the axis of said cylindrical chamber in relation to the roller axis.

20. The compacting device of claim 12, which includes: counterweight means mounted for rotation with said eccentric about the axis of the vibratory roller.

21. A rotatable eccentric for producing a variable amplitude vibratory force upon rotation, comprising: a fluid reservoir chamber and an eccentric fluid chamber rOtatable about a common axis of rotation; first adjustable valve means interconnecting said reservoir chamber and said eccentric chamber for controlling the amount of fluid transferred from said reservoir chamber to said eccentric chamber under the action of centrifugal forces generated upon rotation of the eccentric to produce a variable amplitude vibratory force; and second adjustable valve means interconnecting said reservoir chamber and said eccentric chamber for permitting a portion of the fluid transferred from said reservoir chamber to said eccentric chamber during rotation of the eccentric to return by gravity to said reservoir chamber upon termination of the rotation.

23. The rotatable eccentric of claim 21, wherein: said fluid reservoir chamber comprises a hollow cylinder having closed ends with its axis displaced from the common axis of rotation; and said eccentric chamber is mounted on said cylinder on the opposite side of the axis of rotation from the axis of said cylinder.

24. The rotatable eccentric of claim 21, wherein: said first adjustable valve means includes a first inlet member having an inlet orifice in fluid communication with said fluid reservoir chamber and capable of movement between various radial positions in said fluid reservoir chamber relative to the axis of rotation for receiving fluid from said fluid reservoir chamber upon rotation of the eccentric; and said second adjustable valve means includes a second inlet member having an inlet orifice in fluid communication with said eccentric chamber and capable of movement between various radial positions in said eccentric chamber relative to the axis of rotation for receiving fluid from said eccentric chamber upon termination of rotation of the eccentric; and which includes first conduit means for coupling said first adjustable valve means to said eccentric chamber to permit fluid received by said first inlet member to be transferred to eccentric chamber; and second conduit means for coupling said second adjustable valve means to said fluid reservoir chamber to permit fluid received by said second inlet member to be returned by gravity to said fluid reservoir chamber.

25. The rotatable eccentric of claim 23, wherein: said first adjustable valve means includes a first valve block mounted in an opening formed at one end of said cylinder, said first valve block including a recess formed on its front surface in fluid communication with the interior of said cylinder, and a first disc rotatably mounted in said recess formed in said first valve block having a first inlet orifice extending completely through said first disc at a position spaced radially from the axis of said first disc; and said second adjustable valve means comprises a second valve block mounted in an opening formed at one end of said eccentric chamber, said second valve block including a recess formed on its front surface in fluid communication with the interior of said eccentric chamber, and a second disc rotatably mounted in said recess formed in said second valve block having a second inlet orifice extending completely through said second disc at a position spaced radially from the axis of said second disc; and which includes conduit means for coupling said first adjustable valve means to said eccentric chamber to permit fluid admitted into said recess in said first valve block through said first inlet orifice to be transferred to said eccentric chamber upon rotation of the eccentric; and second conduit means for coupling said second adjustable valve means to the interior of said cylinder to permit fluid admitted into said recess in said second valve block through said second inlet orifice to be transfErred to said cylinder upon termination of the rotation of the eccentric.

26. The rotatable eccentric of claim 25, which includes: means for simultaneously rotating said first and second discs to adjust said first and second inlet orifices to desired radial positions.

27. The rotatable eccentric of claim 26, wherein: said first adjustable valve means includes a shaft rotatably received in a passage extending through said first valve block for supporting said first disc for rotation in said recess formed in said first valve block; said second adjustment valve means includes a second shaft rotatably received in a passage extending through said second valve block for supporting said second disc for rotation in said recess formed in said second valve block; and said means for simultaneously rotating said first and second discs includes a first gear wheel secured to said first shaft, a second gear wheel secured to said second shaft, and a chain for connecting said first and second gear wheels for simultaneous rotation.

28. The rotatable eccentric of claim 23, which includes: a baffle plate extending radially inward from the interior of said cylinder for restricting fluid movement in said cylinder during rotation of the eccentric.

29. A compacting device, comprising: a support; a roller rotatably mounted on said support; and a rotatable eccentric mounted within said roller for rotation about the roller axis independently of said roller to produce a variable amplitude vibratory force upon rotation, said eccentric comprising first and second fluid chambers eccentrically rotatable about the roller axis independently of rotation of said roller; and fluid conduit means interconnecting said chambers, said fluid conduit means including an inlet member located in said first chamber and movable between various positions in said first chamber for controlling the amount of fluid transfer from said first chamber to said second chamber upon rotation of said eccentric to produce a variable amplitude vibratory force.

30. A compacting device, comprising: a support; a vibratory roller mounted on said support for rotation about its axis; a rotatable eccentric mounted within said roller for rotation about the roller axis independently of the roller to produce a variable amplitude force, said rotatable eccentric comprising an eccentric fluid chamber rotatable about the roller axis for producing a vibratory force upon rotation; a fluid reservoir rotatable about the roller axis for supplying fluid to said eccentric fluid chamber under the action of centrifugal forces generated upon rotation of said reservoir; and fluid conduit means interconnecting said eccentric fluid chamber and said reservoir, said fluid conduit means including an inlet member located in said reservoir and movable between various positions in said reservoir for controlling the amount of fluid transfer from said reservoir to said eccentric fluid chamber as a result of the centrifugal forces to permit the amplitude of the vibratory force to be adjusted.