Patent Description:
Certain soil compaction machines may operate with a vibratory eccentric system that assists in the compaction of a substrate, such as. for example, soil or asphalt. Depending on the substrate type and/or requirements of the job, an operator of the compaction machine may select from drum configurations that provide a desired compaction. Compaction vibration may often times be adjusted, for example, by adjusting a speed or frequency at which an eccentric mass(es) rotates. Additionally, often times, the vibrational impact force or amplitude may be adjustable.

In some designs, the amplitude is adjusted by the provision of a rotatable joint that connects an inner secondary eccentric mass to an outer primary eccentric mass. The rotatable joint allows relative phase changes between the primary and secondary weight about an axis of rotation. Due to the forces involved during the operation of such vibratory eccentric systems, the rotatable joint between the primary and secondary weight is subject to significant wear and risk of failure.

The present invention is directed to an improved vibratory eccentric system for compaction machines.

<CIT> relates to an eccentric shaft for a compaction machine. The eccentric shaft comprises a fixed eccentric mass and a movable eccentric mass. A compaction machine having a drum comprising two separate eccentric shafts is also presented.

According to the invention, an eccentric assembly for a compaction machine according to claim <NUM> is provided.

According to other embodiments of inventive concepts, a compaction machine may include a chassis, a drum, an eccentric assembly mounted inside the drum, and a vibration motor coupled to the eccentric assembly. The drum is rotatably connected to the chassis to allow rotation of the drum over a work surface. The eccentric assembly includes an outer eccentric mass, a first inner eccentric mass, and a second inner eccentric mass. A length of the outer eccentric mass is in a direction of an axis of rotation of the outer eccentric mass. The first inner eccentric mass is rotatably connected to the outer eccentric mass by a first joint. The second inner eccentric mass is rotatably connected to the outer eccentric mass by a second joint. Moreover, the first and second inner eccentric masses are separate, and the first and second joints are separate and isolated from each other.

The vibration motor is configured to rotate the outer eccentric mass in a first direction about the axis of rotation of the outer eccentric mass so that the first and second inner eccentric masses move to respective first positions relative to the outer eccentric mass to provide high amplitude vibration, and the vibration motor is configured to rotate the outer eccentric mass in a second direction about the axis of rotation of the outer eccentric mass so that the first and second inner eccentric masses move to respective second positions relative to the outer eccentric mass to provide low amplitude vibration.

The first and second joints may be spaced apart in the direction of the axis of rotation of the outer eccentric mass, the first joint may be aligned with a center of mass of the first inner eccentric mass, and the second joint may be aligned with a center of mass of the second inner eccentric mass. The first joint may be a first double shear joint, and the second joint may be a second double shear joint.

The first double shear joint may include a first tab extending from the outer eccentric mass in a direction orthogonal with respect to the axis of rotation, and the second double shear joint may include a second tab extending from the outer eccentric mass in a direction orthogonal with respect to the axis of rotation. The first double shear joint may include third and fourth tabs extending from the first inner eccentric mass to opposite sides of the first tab and a first pin extending through the first, third, and fourth tabs. Similarly, the second double shear joint may include fifth and sixth tabs extending from the second inner eccentric mass to opposite sides of the second tab and a second pin extending through the second, fifth, and sixth tabs. Moreover, the first pin may define an axis of rotation of the first double shear joint that is parallel with the axis of rotation of the outer eccentric mass, and the second pin may define an axis of rotation of the second double shear joint that is parallel with the axis of rotation of the outer eccentric mass,.

The eccentric assembly may also include first and second stops extending from the outer eccentric mass. The first stop may be longitudinally centered with respect to the first joint and with respect to the center of mass of the first inner eccentric mass. The second stop may be longitudinally centered with respect to the second joint and with respect to the center of mass of the second inner eccentric mass, and the first and second stops may be spaced apart. A line of action of the first stop may extend through the center of mass of the first inner eccentric mass and orthogonal to the axis of rotation of the first joint, and a line of action of the second stop may extend through the center of mass of the second inner eccentric mass and orthogonal to the axis of rotation of the second joint.

The outer eccentric mass may have a recess. The first and second inner eccentric masses may be configured to move to respective first positions seated in the recess of the outer eccentric mass and spaced apart from the respective first and second stops responsive to rotation of the outer eccentric mass in a first direction about the axis of rotation of the outer eccentric mass. The first and second inner eccentric masses may be configured to move to respective second positions against the respective first and second stops responsive to rotation of the outer eccentric mass in a second direction about the axis of rotation of the outer eccentric mass.

In addition, first and second mounting journals may extend from opposite ends of the outer eccentric mass, with the first and second mounting journals being aligned with the axis of rotation of the outer eccentric mass.

The eccentric assembly may further include a third inner eccentric mass between the first and second inner eccentric masses. The third inner eccentric mass may be rotatably connected to the outer eccentric mass by a third joint. Moreover, the first, second, and third inner eccentric masses are separate, and the first, second, and third joints are separate. The first, second, and third inner eccentric masses may have a same mass, or the third inner eccentric mass may have a mass that is different than that of the first and second inner eccentric masses.

According to another aspect, a compaction machine may include a chassis, a drum, an eccentric assembly mounted inside the drum, and a vibration motor coupled to the eccentric assembly. The drum is rotatably connected to the chassis to allow rotation of the drum over a work surface. The eccentric assembly includes an outer eccentric mass, a first inner eccentric mass, and a second inner eccentric mass. A length of the outer eccentric mass is in a direction of an axis of rotation of the outer eccentric mass. The first inner eccentric mass is rotatably connected to the outer eccentric mass by a first joint. The second inner eccentric mass is rotatably connected to the outer eccentric mass by a second joint. Moreover, the first and second inner eccentric masses are separate, and the first and second joints are separate. The vibration motor is configured to rotate the outer eccentric mass in a first direction about the axis of rotation of the outer eccentric mass so that the first and second inner eccentric masses move to respective first positions relative to the outer eccentric mass to provide high amplitude vibration, and the vibration motor is configured to rotate the outer eccentric mass in a second direction about the axis of rotation of the outer eccentric mass so that the first and second inner eccentric masses move to respective second positions relative to the outer eccentric mass to provide low amplitude vibration.

The first and second joints may be spaced apart in the direction of the axis of rotation of the outer eccentric mass, the first joint may be aligned with a center of mass of the first inner eccentric mass, and the second joint may be aligned with a center of mass of the second inner eccentric mass. The first joint may be a first double shear joint, and the second joint may be a second double shear joint. The first double shear joint may include a first tab extending from the outer eccentric mass in a direction orthogonal with respect to the axis of rotation, and the second double shear joint may include a second tab extending from the outer eccentric mass in a direction orthogonal with respect to the axis of rotation. The first double shear joint may include third and fourth tabs extending from the first inner eccentric mass to opposite sides of the first tab and a first pin extending through the first, third, and fourth tabs, and the second double shear joint may include fifth and sixth tabs extending from the second inner eccentric mass to opposite sides of the second tab and a second pin extending through the second, fifth, and sixth tabs. The first pin may define an axis of rotation of the first double shear joint that is parallel with the axis of rotation of the outer eccentric mass, and the second pin may define an axis of rotation of the second double shear joint that is parallel with the axis of rotation of the outer eccentric mass.

The eccentric assembly may further include first and second stops extending from the outer eccentric mass. The first stop may be longitudinally centered with respect to the first joint and with respect to the center of mass of the first inner eccentric mass. The second stop may be longitudinally centered with respect to the second joint and with respect to the center of mass of the second inner eccentric mass, and the first and second stops may be spaced apart. A line of action of the first stop may extend through the center of mass of the first inner eccentric mass and orthogonal to the axis of rotation of the first joint, and a line of action of the second stop may extend through the center of mass of the second inner eccentric mass and orthogonal to the axis of rotation of the second joint.

The outer eccentric mass may have a recess, the first and second inner eccentric masses may be configured to move to the respective first positions seated in the recess of the outer eccentric mass and spaced apart from the respective first and second stops responsive to rotation of the outer eccentric mass in the first direction to provide the high amplitude vibration. The first and second inner eccentric masses may be configured to move to the respective second positions against the respective first and second stops responsive to rotation of the outer eccentric mass in the second direction to provide the low amplitude vibration.

The eccentric assembly may also include first and second mounting journals extending from opposite ends of the outer eccentric mass with the first and second mounting journals being aligned with the axis of rotation of the outer eccentric mass. In addition, the compaction machine may include a coupling between the second journal and the and the vibration motor, with the coupling providing drive input from the vibration motor to the eccentric assembly.

The compaction machine may also include a drive motor coupled with a second drum and/or a traction wheel to propel the compaction machine, and a driver station on the chassis including a steering mechanism to allow a driver to control operation of the compaction machine.

Other eccentric assemblies, drums, and compaction machines according to aspects of embodiments will be or become apparent to those with skill in the art upon review of the following drawings and detailed description.

The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in a constitute a part of this application, illustrate certain non-limiting embodiments of inventive concepts. In the drawings:.

Moreover, certain details of the described embodiments may be modified, omitted, or expanded upon without departing from the scope of the described subject matter. The scope of the invention is solely defined by the appended claims.

<FIG> illustrates a compaction machine <NUM> according to some embodiments of inventive concepts. The compaction machine <NUM> of <FIG> includes a chassis <NUM> and rotatable drums <NUM> located at opposite ends of the chassis <NUM>. In the present embodiment, one or both of the drums <NUM> is/are driven by a drive motor <NUM> and/or <NUM>. As discussed in greater detail below, eccentric assemblies may be used to increase a force F on work surface15.

<FIG>, <FIG>, and <FIG> schematically illustrates a drum <NUM> including a vibratory eccentric system provided with a vibration motor <NUM> and an eccentric assembly <NUM> therein according to some embodiments of inventive concepts. The vibration motor <NUM> rotates the assembly <NUM> about an axis of rotation <NUM> of the eccentric assembly that is parallel with an axis of rotation of the drum.

According to one aspect of the present invention, vibration motor <NUM> is configured to rotate the eccentric assembly <NUM> in a first direction to provide high amplitude vibration and in a second direction that is opposite the first direction to provide low amplitude vibration. Vibrations generated by the rotation of the eccentric assembly increase the force F the compacting surface (i.e., drum <NUM>) exerts on the work surface <NUM> (e.g., soil, asphalt, etc.) and provides improved compaction.

<FIG> and <FIG> are enlarged perspective views of an eccentric assembly of <FIG> in respective high and low amplitude orientations according to some embodiments of inventive concepts. As shown, eccentric assembly <NUM> includes outer eccentric mass <NUM> provided with a shape that is elongated relative to lengths of inner eccentric masses <NUM> and <NUM> with a length in a direction of an axis of rotation <NUM> of the outer eccentric mass. First inner eccentric mass <NUM> is rotatably connected to outer eccentric mass <NUM> by first joint (including tabs 37a, 37b, and 37c, and pin 37d), and second inner eccentric mass <NUM> is rotatably connected to outer eccentric mass <NUM> by second joint (including tabs 39a, 39b, and 39c, and pin 39d). Moreover, first and second inner eccentric masses <NUM> and <NUM> are separate, and the respective first and second joints are separate.

Outer eccentric mass <NUM> may include an elongate recess therein with the recess being substantially co-directional with the length of the outer eccentric mass. Stops <NUM> and <NUM> may extend from outer eccentric mass <NUM>. Accordingly, inner eccentric masses <NUM> and <NUM> may be connected to rotate against a wall <NUM> of the outer eccentric mass <NUM> in the recess in a high amplitude orientation (as shown in <FIG>) or against respective stops <NUM> and <NUM> in a low amplitude orientation (as shown in <FIG>). For high amplitude vibration, vibration motor <NUM> is thus configured to rotate outer eccentric mass <NUM> in a first direction (indicated by the rotational arrow of <FIG>) so that the first and second inner eccentric masses move to respective high amplitude (first) positions as shown in <FIG>. In the high amplitude positions, each of the inner eccentric masses may thus be seated/stopped against wall <NUM> of the recess of the outer eccentric mass and spaced apart from the respective low amplitude stops <NUM> and <NUM>.

For low amplitude vibration, vibration motor <NUM> is configured to rotate outer eccentric mass <NUM> in a second direction (indicated by the rotational arrow of <FIG>) so that the first and second inner eccentric masses move to respective low amplitude (second) positions against stops <NUM> and <NUM> as shown in <FIG>. More particularly, stop <NUM> extends from outer eccentric mass <NUM> with stop <NUM> being longitudinally centered with respect to the center tab 37c of the first joint and with respect to the center of mass <NUM> of inner eccentric mass <NUM> (shown in <FIG>). Similarly, stop <NUM> extends from outer eccentric mass <NUM> with stop <NUM> being longitudinally centered with respect to center tab 39c of the second joint and with respect to the center of mass of inner eccentric mass <NUM>, and with stops <NUM> and <NUM> being spaced apart. By providing separate stops <NUM> and <NUM> that are spaced apart (as opposed to one continuous stop), a mass of material extending beyond the axis of rotation opposite the outer eccentric mass (and thus counteracting high amplitude vibration) may be reduced.

With inner eccentric masses <NUM> and <NUM> in low amplitude positions against respective stops <NUM> and <NUM>, a line of action <NUM> of each stop <NUM> and <NUM> extends through the center of mass <NUM> of the respective inner eccentric mass and orthogonal to the axis of rotation of the respective joint as shown in <FIG>. Moreover, radial line <NUM> extends though the center of mass of the inner eccentric mass and the axis of rotation defined by pin 37d. Accordingly, a moment arm of a joint pin 37d, 39d used in a respective joint may be increased giving greater resistance against a load from the respective inner eccentric mass <NUM> and <NUM> trying to rotate about a low amplitude stop point, thereby reducing load on the pin when the inner eccentric mass contacts the stop.

As shown in <FIG>, the first joint (including tabs 37a, 37b, and 37c, and tab 37d) and the second joint (including tabs 39a, 39b, and 39c, and tab 39d) are spaced apart in the direction of the axis of rotation of the outer eccentric mass. Moreover, the first joint is aligned with a center of mass of inner eccentric mass <NUM>, and the second joint is aligned with a center of mass of the inner eccentric mass <NUM>. Stated in other words, a center of mass of each inner eccentric mass may be radially aligned with a longitudinal center of the respective joint as discussed in greater detail below with respect to <FIG>. More particularly, the first and second joints may be respective double shear joints (also referred to as pin joints or knuckle joints), with each joint including one tab extending from the outer eccentric mass in a direction orthogonal with respect to the axis of rotation, two tabs extending from the inner eccentric mass, and a pin extending through the three tabs. <FIG> is a cross sectional view illustrating elements of the first joint (including tabs 37a, 37b, and 37c, and pin 37d) used for eccentric mass <NUM>. As shown, tabs 37a and 37b extend from inner eccentric mass <NUM>, tab 37c extends from outer eccentric mass <NUM> between tabs 37a and 37b, and pin 37d extends through each of tabs 37a, 37b, and 37c. For each double shear joint, the pin thus defines an axis of rotation of the double shear joint that is parallel with the axis of rotation of outer eccentric mass <NUM>. According to some embodiments, the axis of rotation of outer eccentric mass <NUM>, the axis of rotation of the first joint (defined by pin 37d), and the axis of rotation of the second joint (defined by pin 39d) may all be coincident. Moreover, each of these axes of rotation may be coincident with the axis of rotation of drum <NUM>.

As shown in <FIG>, center of mass <NUM> of eccentric mass <NUM> may thus be radially aligned with a longitudinal center of the first joint indicated by line <NUM>. For example, center of mass <NUM> of inner eccentric mass <NUM> may be radially aligned with a center tab (e.g., tab 37c) of the respective joint. While center tab 37c is shown extending from outer eccentric mass <NUM>, center tab 37c could extend from inner eccentric mass <NUM> with tabs 37a and 37b extending from outer eccentric mass <NUM>.

The double shear joint design of <FIG> and <FIG> thus supports the pin in double shear to reduce bending load on the pin that may result from weight of the respective inner eccentric mass and/or centrifugal force of the respective inner eccentric mass. Moreover, by providing two separate inner eccentric masses <NUM> and <NUM>, the respective double shear joints (also referred to as pin joints or knuckle joints) are isolated from each other, thereby reducing bending load on the pins that could result from bending of a single longer inner eccentric mass and/or bending of the outer eccentric mass. Each pin may thus be substantially subjected to only a shearing load. Moreover, each tab 37c, 39c extending from the outer eccentric mass <NUM> may be aligned with a center of mass of the respective inner eccentric mass <NUM>, <NUM> in a radial direction from the axis of rotation defined by the respective pin 37d, 39d.

<FIG> is an exploded view of eccentric assembly <NUM> of <FIG> according to some embodiments of inventive concepts. The first joint thus includes tabs 37a, 37b, and 37c and pin 37d, and the second joint includes tabs 39a, 39b, and 39c and pin 39d. In addition, each joint may include washers <NUM>, bushings <NUM>, and snap rings <NUM> (used to hold the pin in place) as shown in the exploded view of the first joint. Outer eccentric mass <NUM> may also include mounting journals <NUM> and <NUM> extending from opposite ends thereof. These mounting journals <NUM> and <NUM> may be provided to rotatably mount the eccentric assembly within drum <NUM> of <FIG> on the desired axis of rotation. In addition, coupling <NUM> may be attached to mounting journal <NUM> using washers <NUM> and screws <NUM> to provide rotational drive input from vibration motor <NUM> of <FIG>. Journal <NUM> may mount to vibration motor <NUM> and/or drum <NUM> of <FIG>.

By providing multiple inner eccentric masses, double shear joints for each inner eccentric mass, and/or raised stops for the low amplitude operation, stress on the joint pins may be reduced thereby reducing pin failure and/or allowing reduced pin size/material (i.e., less expensive pins may be used). Raised stops <NUM> and <NUM> for low amplitude operation may reduce impact load on the joint pins when the respective inner eccentric masses contact the respective stops <NUM> and <NUM>. By supporting joint pins in double shear using tabs as discussed above, bending load on the pins may be reduced. By providing separate inner eccentric masses <NUM> and <NUM>, the joint pins for the respective inner eccentric masses may be isolated from each other to thereby reduce bending load on the joint pins due to deflection of a longer inner eccentric mass and/or deflection of the outer eccentric mass. Use of a split inner eccentric mass and loose fit joint pins may also increase ease of assembly and/or serviceability.

As shown in <FIG>, <FIG>, and <FIG>, inner eccentric masses <NUM> and <NUM> may have the same mass, size, and shape, for example, to provide symmetry for the eccentric assembly. According to some other embodiments, eccentric masses <NUM> and <NUM> may have different masses, sizes, and/or shapes, for example, to compensate for a non-centered placement of the eccentric assembly in a drum (e.g., shifted to one side of the drum or the other).

In addition, efficient use of mass in shaping of the outer eccentric mass <NUM> and inner eccentric masses <NUM> and <NUM> may provide improved efficiency of use with reduced power draw and thus reduced fuel consumption without reducing functional performance. Accordingly, design flexibility for a compaction machine <NUM> may be increased by allowing use of smaller and/or more efficient components (e.g., for hydraulic and/or powertrain systems).

Moreover, while two inner eccentric masses are discussed by way of example, eccentric assemblies may include any number of inner eccentric masses according to some embodiments of inventive concepts and as long as compatible with claim <NUM>. For example, three inner eccentric masses may be used with one outer eccentric mass, and a separate double shear joint and low amplitude stop may be provided for each of the three inner eccentric masses.

<FIG> illustrates an example of an eccentric assembly including an outer eccentric mass and first, second, and third inner eccentric masses according to some embodiments of inventive concepts. In <FIG>, outer eccentric mass <NUM>' may be similar to outer eccentric mass <NUM> of <FIG> and <FIG> except that outer eccentric mass <NUM>' is longer with a longer recess, and with an additional stop <NUM> and an additional tab 77c to accommodate third inner eccentric mass <NUM>. Inner eccentric mass <NUM> and related elements (including tabs 37a, 37b, and 37c, and stop <NUM>) and inner eccentric mass <NUM> and related elements (including tabs 39a, 39b, 39c, and stop <NUM>) may be substantially the same as inner eccentric masses <NUM> and <NUM> (and related elements) of <FIG> and <FIG>. In addition, the eccentric assembly of <FIG> may include third inner eccentric mass <NUM> between inner eccentric masses <NUM> and <NUM>, and tabs 77a, 77b, and 77c, and pin 77d may provide a double shear joint for inner eccentric mass <NUM>. Inner eccentric mass <NUM> may thus rotate between a high amplitude position (spaced apart from stop <NUM>) and a low amplitude position (against stop <NUM>) depending on a direction of rotation of the eccentric assembly <NUM>', as discussed above with respect to inner eccentric masses <NUM> and <NUM>.

Third inner eccentric mass <NUM>, for example, may be useful for a larger eccentric assembly where use of only two eccentric masses might require lengths that are longer than desired. Moreover, a size/mass of inner eccentric mass <NUM> (in the middle) may be different than sizes of inner eccentric masses <NUM> and <NUM> while still maintaining symmetry of the eccentric assembly. For example, a mass/length of inner eccentric mass <NUM> may be less than that of inner eccentric masses <NUM> and <NUM> as shown in <FIG>, or a mass/length of inner eccentric mass <NUM> may be the same as that of inner eccentric masses <NUM> and <NUM>, depending on a desired size of the assembly.

In the above-description of various embodiments of the present disclosure, it is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

When an element is referred to as being "connected", "coupled", "responsive", "mounted", or variants thereof to another element, it can be directly connected, coupled, responsive, or mounted to the other element or intervening elements may be present. In contrast, when an element is referred to as being "directly connected", "directly coupled", "directly responsive", "directly mounted" or variants thereof to another element, there are no intervening elements present. The term "and/or" and its abbreviation "/" include any and all combinations of one or more of the associated listed items.

As used herein, the terms "comprise", "comprising", "comprises", "include", "including", "includes", "have", "has", "having", or variants thereof are open-ended, and include one or more stated features, integers, elements, steps, components or functions but do not preclude the presence or addition of one or more other features, integers, elements, steps, components, functions or groups thereof.

Claim 1:
An eccentric assembly (<NUM>) for a compaction machine (<NUM>), the eccentric assembly (<NUM>) comprising:
an outer eccentric mass (<NUM>) with a length in a direction of an axis of rotation of the outer eccentric mass (<NUM>);
a first inner eccentric mass (<NUM>) rotatably connected to the outer eccentric mass (<NUM>) by a first joint (<NUM>); and
a second inner eccentric mass (<NUM>) rotatably connected to the outer eccentric mass (<NUM>) by a second joint (<NUM>), wherein the first and second inner eccentric masses (<NUM>, <NUM>) are separate, and
characterized in that the first and second joints (<NUM>, <NUM>) are separate and are isolated from each other.