Patent Description:
Surface compactor machines, or surface compactors, are used to compact a variety of substrates, such as asphalt and soil. Surface compactors are provided with one or more compacting surfaces for this purpose. For example, a roller compactor may be provided with one or more cylindrical drums that provide compacting surfaces for compacting soil, asphalt, or other materials.

Roller compactors use the weight of the compactor to compress the surface being rolled. In addition, one or more of the drums of some roller compactors may vibrate to induce additional mechanical compaction of the surface being rolled.

Heavy duty surface compactors typically have two rollers or drums, e.g., front and back rollers, that provide compaction of the surface. An operator cab may be positioned between the rollers. The drums in such a compactor, referred to as tandem drums, may vibrate or be static, and may be driven by a motor mounted next to or under the operator cab.

A single-drum (or uni-drum) compactor only includes a single compacting drum. A conventional single drum compactor may include drive tires that propel the compactor and an operator cab positioned between the drum and the drive tires. For light duty, walk behind single drum compactors are also known. Such compactors may be driven by motors provided within the drum.

German Patent Application <CIT> discloses according to its abstract a vibratory roller with at least one tyre having a built-in twin-shaft vibration generator, the roller design making it possible to cause the vibration generator to execute optionally either a circular oscillatory motion or a directional motion with respect to the axis of rotation of the roller tyre. Unbalanced shafts are disposed coaxially with respect to each other and to the axis of rotation of the roller and can be coupled to each other in different ways, either to rotate in the same direction or to rotate in opposite directions. It is possible in each case to change the phase relationship of the unbalanced shafts with respect to each other.

French Patent Application <CIT> discloses according to its abstract a self-propelled road roller or similar machine of the type used for the agglomeration of asphalt wearing surfaces and asphalt macadam as well as for the compaction of particulate materials. The self-propelled road roller, or machine of the same type comprises a pair of cylinders arranged side by side and coaxially, a frame pivotally supported by the common axis of the cylinders, a device for imparting vibration to the cylinders, a device for driving the cylinders independently of each other and a balancing device arranged on the frame and adjustable in order to keep the roller in balance whatever the conditions under which it is called upon to operate. The driving of the cylinders and of the vibratory device is ensured by hydraulic motors powered by a suitable pump driven by an internal combustion engine and mounted on the frame.

US Patent Application <CIT> discloses according to its abstract a vibratory compactor which includes a roller and an eccentric shaft. The roller is rotatably mounted on a main frame and may include a first vertical support and a second vertical support. The eccentric shaft is rotatably connected between the first vertical support and the second vertical support in the roller. The eccentric shaft includes a first end, a second end, a first eccentric weight, a second eccentric weight, and a center portion, casted as a single piece. The first eccentric weight is proximal to the first end and the second eccentric weight is proximal to the second end. The center portion may be disposed between the first eccentric weight and the second eccentric weight. The center portion may include at least one cavity on a surface of the center portion. The at least one cavity is elongated between the first eccentric weight and the second eccentric weight.

This summary is provided to introduce simplified concepts that are further described below in the Detailed Description.

A surface compactor machine according to independent claim <NUM> includes a cylindrical drum including a cylindrical drum shell and a cylindrical spool disposed within the cylindrical drum shell and supporting the cylindrical drum shell, and an eccentric assembly mechanically coupled to the cylindrical drum and arranged to impart vibration to the cylindrical drum when the eccentric assembly is rotated. The cylindrical drum and the eccentric assembly form part of an unsprung mass having a combined first center of gravity. A head plate is affixed to the cylindrical spool through a shock isolator, and a sprung mass is rotationally coupled to the head plate along an axis of rotation of the cylindrical drum shell and the cylindrical spool. The sprung mass includes a plurality of components having a combined second center of gravity that is lower than the first center of gravity when the surface compactor machine is in a stationary position. The sprung mass includes a traction system including a traction motor and a slewing gear coupled to the traction motor. The traction system rotates the sprung mass relative to the head plate about the axis of rotation.

In an aspect, when the surface compactor machine is in the stationary position, the first center of gravity of the unsprung mass and the second center of gravity of the sprung mass are in vertical alignment.

In an aspect, when the traction system rotates the sprung mass relative to the head plate about the axis of rotation, the second center of gravity of the sprung mass is rotated out of vertical alignment with the first center of gravity of the unsprung mass, thereby imparting torque to the cylindrical drum that causes rotation of the cylindrical drum.

In an aspect, the rotation imparted to the cylindrical drum imparts linear motion of the cylindrical drum in a direction from the first center of gravity of the unsprung mass toward the second center of gravity of the sprung mass.

In an aspect, the shock isolator provides vibrational isolation of the sprung mass from vibration of the cylindrical drum generated by the eccentric assembly.

In an aspect, the eccentric assembly includes an eccentric shaft disposed with in the cylindrical drum and rotationally driven by a vibration motor.

In an aspect, the slewing gear is coupled to the head plate.

In an aspect, the traction motor is coupled to the slewing gear through a planetary gear.

In an aspect, the traction system includes a drive shaft coupled to the traction motor and the slewing gear and a safety brake coupled to the drive shaft.

In an aspect, the vibration motor is positioned outside the head plate relative to the cylindrical spool and is coupled to the eccentric shaft through a constant velocity joint.

In an aspect, the surface compactor machine further includes a frame forming part of the sprung mass, wherein the traction system is mounted to the frame.

In an aspect, the frame extends partially within a space defined by the cylindrical drum shell adjacent the cylindrical spool, and wherein the drive motor is disposed at least partially within the space defined by the cylindrical drum shell adjacent the cylindrical spool.

In an aspect, the sprung mass further includes an engine mounted on the frame, a counterweight mounted on the frame, and/or a bumper mounted on the frame.

In an aspect, the surface compactor machine further includes a second head plate affixed to the second cylindrical spool through a second shock isolator, and a second traction system including a second traction motor and a second slewing gear coupled to the second traction motor, wherein the second traction system is configured to rotate the sprung mass relative to the second head plate about the axis of rotation.

<FIG> is a perspective view of a single drum surface compactor machine <NUM> according to some embodiments. As will be appreciated, a single drum surface compactor machine may be a self-propelled autonomous or semi-autonomous vehicle for compacting a substrate.

Referring to <FIG>, the surface compactor machine <NUM> has a split drum construction. In particular, the surface compactor machine <NUM> includes a split cylindrical drum <NUM> including first and second cylindrical drums 12a, 12b arranged along a common axis of rotation. Each of the cylindrical drums 12a, 12b includes an independent drive system and can rotate independently to allow the surface compactor machine <NUM> to move forward/backward, steer left of right, and/or to change directions. Each of the cylindrical drums 12a, 12b includes a cylindrical drum shell 14a, 14b that contacts an underlying substrate. Compaction of the substrate is achieved as a result of the weight of the surface compactor machine <NUM> as it rolls over the substrate. Compaction of the substrate may be enhanced by vibration of the cylindrical drums 12a, 12b, as described in more detail below.

<FIG> is a cutaway perspective view, <FIG> is a side cutaway view, and <FIG> is a plan cutaway view of the surface compactor machine <NUM> showing various internal components of the surface compactor machine <NUM>. <FIG> is a side elevation of the surface compactor machine <NUM>.

Referring to <FIG>, each of the cylindrical drums 12a, 12b of the surface compactor machine <NUM> includes a cylindrical spool 16a, 16b disposed within the cylindrical drum shell 14a, 14b. As best seen in <FIG>, the cylindrical drums 12a, 12b and the cylindrical spools 16a, 16b rotate around a common axis of rotation <NUM>. The cylindrical spools 16a, 16b are coupled together by means of a slewing bearing <NUM> (<FIG>), which allows independent rotation of the cylindrical drums 12a, 12b about the axis of rotation <NUM>.

The surface compactor machine <NUM> includes an eccentric assembly <NUM> that is mechanically coupled to the cylindrical drums 12a, 12b and arranged to impart vibration to the cylindrical drum when the eccentric assembly <NUM> is rotated. The cylindrical drums 12a, 12b and the eccentric assembly <NUM> form part of an unsprung mass <NUM> having a combined first center of gravity G1 approximately near the axis of rotation <NUM> (<FIG>). As will be described in more detail below, other components of the surface compactor machine <NUM> form a sprung mass <NUM> that is at least partially isolated from vibration of the unsprung mass <NUM> by means of shock isolators, although some vibration of the unsprung mass <NUM> may be transmitted through the shock isolators to the sprung mass <NUM>.

Referring to <FIG>, a head plate 24a, 24b is affixed to each cylindrical spool 16a, 16b through a respective set of shock isolators 26a, 26b. The shock isolators 26a, 26b provide vibrational isolation of the sprung mass <NUM> from vibration of the cylindrical drums 12a, 12b generated by rotation of the eccentric assembly <NUM>. A frame 60a, 60b is mounted to the head plate 24a, 24b through a slewing gear 38a, 38b. A portion of the frame 60a, 60b may extend partially into a space defined by the cylindrical drum shell 14a, 14b adjacent the spool 16a, 16b. Elements of the sprung mass <NUM> may be mounted to the frame 60a, 60b.

The eccentric assembly includes an eccentric shaft <NUM> disposed within the cylindrical drums 12a, 12b and rotationally driven by a vibration motor <NUM> that is mounted outside the spools 16a, 16b in the illustrated embodiment. The vibration motor <NUM>, which is mounted to the frame 60a, forms part of the sprung mass <NUM> and is at least partially isolated from vibration of the eccentric assembly <NUM>. The vibration motor <NUM> is coupled to the eccentric shaft <NUM> through a constant velocity joint <NUM>. The vibration motor <NUM> rotates the eccentric assembly to impart vibration to the drums 12a, 12b to enhance compaction of the substrate. The continuous velocity joint <NUM> is able to transfer high speed and bear with deflections of the shock isolators 26a, 26b. This construction enhances isolation of the electrical and electronical components from vibrations, since all electrical components are mounted on the cushioned frame 60a, 60b.

The sprung mass <NUM> includes a plurality of components having a combined second center of gravity G2 (<FIG>) that is lower than the first center of gravity G1 when the surface compactor machine <NUM> is in a stationary position (i.e., the drums 12a, 12b are not rotating).

Referring to <FIG>, the sprung mass <NUM> includes traction systems 34a, 34b for each of the drums 12a, 12b. The traction systems 34a, 34b each include a traction motor 36a, 36b and a slewing gear 38a, 38b coupled to the traction motor 36a, 36b. The traction motor 36a, 36b and slewing gear 38a, 38b are mounted to the frame 60a, 60b. The traction system includes a drive shaft 48a, 48b coupled to the traction motor 36a, 36b and the slewing gear 38a, 38b, and a safety brake 52a, 52b coupled to the drive shaft 48a, 48b. The traction motor 36a, 36b is coupled to the slewing gear 38a, 38b through a <NUM>-degree planetary reduction gear 46a, 46b. The slewing gear 38a, 38b contacts a slewing bearing 40a, 40b that is coupled to the head plate 24a, 24b. As is known in the art, a slewing bearing permits independent rotation of the joined bodies. In this case, the slewing bearing 40a, 40b, which is centered on the axis of rotation <NUM>, enables independent rotation of the sprung mass <NUM> connected to the frame 60a, 60b and the unsprung mass <NUM> connected to the head plate 24a, 24b. When the traction motor 36a, 36b turns the slewing gear 38a, 38b via the drive shaft 48a, 48b,the the sprung mass <NUM> rotates about the axis of rotation <NUM> independently of the unsprung mass <NUM>. That is, when the slewing gear 38a, 38b is driven by the traction motor 36a, 36b against the slewing bearing 40a, 40b, the sprung mass <NUM> rotates about the axis of rotation <NUM> relative to the unsprung mass <NUM>.

Accordingly, in each drum 12a, 12b, the traction system 34a, 34b rotates the sprung mass <NUM> about the axis of rotation <NUM> relative to the head plate 24a, 24b and the unsprung mass <NUM>. The sprung mass <NUM> is rotationally coupled to the head plate 24a, 24b along the axis of rotation <NUM> of the cylindrical drum shells 14a, 14b and the cylindrical spools 16a, 16b via the slewing bearings 40a, 40b.

As shown in <FIG>, the traction systems 34a, 34b are offset from the central axis of rotation <NUM> of the drums 12a, 12b. This offset between the central axis of the traction motors 36a, 36b and the center of the drums 12a, 12b using slewing gears 38a, 38b allows the system to directly drive the eccentric assembly <NUM> along the central axis <NUM> of the drum 12a via the constant velocity joint <NUM>.

The sprung mass <NUM> further includes a number of other components mounted to the frame 60a, 60b and that contribute to the mass of the sprung mass <NUM>. For example, as shown in <FIG>, the sprung mass <NUM> further includes an engine <NUM> mounted on the frame, a counterweight <NUM> mounted on the frame, and/or a bumper 64a, 64b mounted on the frame 60a, 60b. Water tanks may be mounted in the bumper 64a, 64b which may also add further mass to the sprung mass <NUM>.

Referring to <FIG> and <FIG>, when the surface compactor machine is in the stationary position, the first center of gravity G1 of the unsprung mass <NUM> and the second center of gravity G2 of the sprung mass <NUM> are in vertical alignment (<FIG>).

When the traction system 34a, 34b rotates the sprung mass <NUM> relative to the head plate 24a, 24b about the axis of rotation <NUM> (for example, by an angle of rotation A1 shown in <FIG>), the second center of gravity G2 of the sprung mass <NUM> is rotated out of vertical alignment with the first center of gravity G1 of the unsprung mass <NUM>. In the example shown in <FIG>, the second center of gravity G2 of the sprung mass <NUM> is rotated out of vertical alignment with the first center of gravity G1 of the unsprung mass <NUM>. This rotation of the second center of gravity G2 of the sprung mass <NUM> relative to the first center of gravity G1 of the unsprung mass <NUM> lifts the second center of gravity G2 of the sprung mass <NUM>. The gravitational force on the sprung mass <NUM> causes an imbalance within the surface compactor machine <NUM>. As the force of gravity attempts to correct this imbalance by pulling the second center of gravity G2 of the sprung mass <NUM> back down beneath the first center of gravity of the unsprung mass <NUM>, friction between the ground and the cylindrical drum 12a, 12b imparts torque to the cylindrical drum 12a, 12b, which in turn causes rotation of the cylindrical drum 12a, 12b in a direction toward the rotated center of gravity of the sprung mass <NUM>.

That is, the rotation imparted to the cylindrical drum 12a, 12b imparts linear (forward or backward) motion of the cylindrical drum 12a, 12b in a direction <NUM> from the first center of gravity G1 of the unsprung mass <NUM> toward the second center of gravity G2 of the sprung mass <NUM>.

Accordingly, a surface compactor machine <NUM> according to some embodiments includes an unsprung mass <NUM> having a first center of gravity, the unsprung mass including a cylindrical drum 12a, 12b including a cylindrical drum shell 14a, 14b and a cylindrical spool 16a, 16b disposed within the cylindrical drum shell 14a, 14b and supporting the cylindrical drum shell 14a, 14b, and a sprung mass <NUM> rotationally coupled to the cylindrical spool along an axis of rotation <NUM> of the cylindrical drum shell 14a, 14b and the cylindrical spool 16a, 16b. The sprung mass <NUM> has a second center of gravity G2 that is lower than the first center of gravity G1 when the surface compactor machine is in a stationary position. The sprung mass <NUM> includes a traction system 34a, 34b including a traction motor 36a, 36b and a slewing gear 38a, 38b coupled to the traction motor. The traction system 34a, 34b is configured to rotate the sprung mass <NUM> relative to the cylindrical spool 16a, 16b about the axis of rotation <NUM>. When the surface compactor machine <NUM> is in the stationary position, the first center of gravity G1 of the unsprung mass <NUM> and the second center of gravity G2 of the sprung mass <NUM> are in vertical alignment, and when the traction system 34a, 34b rotates the sprung mass <NUM> relative to the cylindrical spool 16a, 16b about the axis of rotation <NUM>, the second center of gravity G2 of the sprung mass <NUM> is rotated out of vertical alignment with the first center of gravity G1 of the unsprung mass <NUM>, thereby imparting torque to the cylindrical spool 16a, 16b that causes rotation of the cylindrical drum 12a, 12b.

Accordingly, as described above, the sprung mass <NUM>, which includes all components other than the drum 12a, 12b and the eccentric assembly <NUM>, is connected with the drum 12a, 12b by a slewing gear 38a, 38b including slewing bearings. The sprung mass <NUM> has a center of gravity that is displaced from the center of the slewing bearing. Therefore, gravity works to maintain the designed position of the sprung mass <NUM> without any additional controls or actuators. Heavy components of the sprung mass, such as an internal combustion engine, generator, ultra capacitors, counterweights, etc., are mounted as low as possible in order to keep the frame 60a, 60b in a horizontal position without active control.

Some embodiments include symmetrical electrical powertrains for both halves of the split drum 12a, 12b. Moreover, each drum 12a, 12b includes an electrical traction motor 36a, 36b with a reduction gear 46a, 46b and slewing gear 38a, 38b for driving the drum 12a, 12b.

To better utilize space inside the drum 14a, 14b, and to protect components from vibrations, the shock isolators 26a, 26b are mounted directly to the drum spools 16a, 16b.

Various elements of the machine could be modified. For example, in some embodiments, the engine <NUM> and generator could be omitted and the drive motors could be powered from batteries/ultra capacitors and be fully electric. The angular planetary gear 46a, 46b could be replaced by straight planetary gear provided that the drive motor 36a, 36b were rotated by <NUM> degrees. The slewing slewing gear 38a, 38b could be functionally divided into separate units of bearing and gear with internal engagement. There could also be one wrapping frame 60a, 60b at the top of the machine <NUM> with tanks and space for electronics. Gyro stabilization could also optionally be provided. The electrical safety brake could be implemented into the drive motor 36a, 36b or its function could be performed by inline disc brakes operated with compressed air. Many other such modifications are possible and could be made within the scope of the appended claims.

While embodiments of the inventive concepts are illustrated and described herein, the device may be embodied in many different configurations, forms and materials. The present disclosure is to be considered as an exemplification of the principles of the inventive concepts and the associated functional specifications for their construction and is not intended to limit the inventive concepts to the embodiments illustrated. Those skilled in the art will envision many other possible variations within the scope of the appended claims.

Claim 1:
A surface compactor machine, comprising:
a cylindrical drum (12a, 12b) comprising a cylindrical drum shell (14a, 14b) and a cylindrical spool (16a, 16b) disposed within the cylindrical drum shell and supporting the cylindrical drum shell, the cylindrical drum shell and the cylindrical spool having an axis of rotation (<NUM>);
an eccentric assembly (<NUM>) mechanically coupled to the cylindrical drum and arranged to impart vibration to the cylindrical drum when the eccentric assembly is rotated, wherein the cylindrical drum and the eccentric assembly form part of an unsprung mass (<NUM>) having a combined first center of gravity;
a head plate (24a, 24b) affixed to the cylindrical spool through a shock isolator (26a, 26b); and wherein the surface compactor machine further comprises:
a sprung mass (<NUM>) comprising a plurality of components having a combined second center of gravity that is lower than the first center of gravity when the surface compactor machine is in a stationary position;
wherein the sprung mass comprises a traction system (34a, 34b) including a traction motor (36a, 36b) and a slewing gear (38a, 38b) coupled to the traction motor, wherein the traction system is configured to rotate the sprung mass relative to the unsprung mass about the axis of rotation,
characterized in that
the sprung mass (<NUM>) is rotationally coupled to the head plate (24a, 24b) along the axis of rotation (<NUM>).