Patent Description:
Between a crane arm tip and a jib-carried tool, a rotator can be arranged so that the tool can be rotated in respect to the crane arm tip. A grapple is an example of a tool and another non-limiting example of a jib-carried tool is a harvester for harvesting trees. The crane system often comprises two or three crane arm parts connected to each other by crane arm joints.

Rotators come in a number of different types and the most common types are electric and hydraulic rotators. This means that the first type is electrically powered whilst the latter type is powered by hydraulic fluid. Rotators are used all over the world besides in forestry, such as in general cargo handling and material handling in ports and scrap yards.

Document <CIT> discloses the preamble of claim <NUM>.

Another objective of embodiments of the invention is to provide a rotator having a compact design in its axial extension.

The above and further objectives are solved by the subject matter of the independent claims.

Further advantageous embodiments of the invention can be found in the dependent claims.

According to a first aspect of the invention, the above mentioned and other objectives are achieved with a rotator for a tool, the rotator comprising:.

characterized in that the rotator further comprises a hydraulic swivel and an electrical swivel and/or an angle meter arranged inside the rotor, wherein the hydraulic swivel and the electrical swivel and/or the angle meter at least partially extends axially in the second axial extension in the rotator, and wherein the hydraulic swivel is axially aligned with the electrical swivel and/or the angle meter inside the rotor along the axis of rotation of the rotator.

Hence, the rotator may comprise a hydraulic swivel and an electrical swivel, a hydraulic swivel and an angle meter, or a hydraulic swivel and an electrical swivel and an angle meter.

That the hydraulic swivel and the electrical swivel and/or an angle meter at least partially extends axially in the second axial extension can be understood that the said hydraulic swivel and said electrical swivel and/or an angle meter has at least one part/section that extends or is inside the second axial extension but can have another parts/section that does not extend or is inside the second axial extension.

The rotator is in embodiments a hydraulic rotator.

The rotator has an extension in its axial direction and an extension in its radial direction. The axial direction may be parallel to or the same as the axis of rotation of the rotator.

The separate bearing may be a bearing separate from the bearing of the rotor. That the separate bearing is configured to carry an external load of the rotator can be understood as that the separate bearing carries a load generated by the tool and possible object(s) held by the tool and possible dynamic forces generated by movement of the tool and its possible object(s), e.g. due to movement of the crane to which the rotator is attached.

An advantage of the rotator according to the first aspect is that the rotator can be made or designed compact in its axial extension. Therefore, the rotator has a low building height. This implies that the tool and its possible object may be lifted higher compared to when the rotator has a higher building height.

Further, the separate bearing implies that the rotator can carry very heavy external loads in contrast to a rotator in which the external load is carried by the rotor.

Moreover, since the electrical swivel and/or the angle meter is arranged inside the rotator said electrical swivel and/or the angle meter are well protected, e.g. from mechanical impact.

In embodiments, at least one of the electrical swivel and the angle meter extends fully in the first axial extension which can be understood that at least one of the electrical swivel and the angle meter does not have an axial extension outside the first axial extension.

In an implementation form of a rotator according to the first aspect, the separate bearing at least partially extends axially in the first axial extension in the rotator.

An advantage with this implementation form is that the rotator can be made even more compact in its axial extension.

According to the invention, the rotator comprises.

The second axial extension is in embodiments of the invention within the first axial extension in the rotor.

The one or more hydraulic chambers can be part of a hydraulic motor configured to rotate the rotor in the stator. Examples of hydraulic motors are hydraulic vane motors and hydraulic piston motors.

In an implementation form of a rotator according to the first aspect, the separate bearing at least partially extends axially in the second axial extension in the rotator.

An advantage with this implementation form that a hydraulic swivel is provided which can be configured to hydraulically feed a tool coupled to the rotator. Further, the rotator comprising a hydraulic swivel can be made compact in its axial extension.

According to the invention, the hydraulic swivel at least partially extends axially in the second axial extension in the rotator.

In an implementation form of a rotator according to the first aspect, the rotator comprises the electrical swivel and the angle meter; and wherein
the angle meter is arranged axially above the electrical swivel inside the rotor.

It is noted that one or more electrical power cables and/or one or more electrical signal cables may be arranged to pass though the angle meter to the electrical swivel in such an implementation form.

An advantage with this implementation form is that electrical swivel may more easily feed the tool with electrical power since it is arranged closer to the tool than the angle meter.

In an implementation form of a rotator according to the first aspect, the electrical swivel and the angle meter are axially aligned with each other inside the rotor along an axis of rotation of the rotator.

An advantage with this implementation form is that the radial extension of the rotator can be made smaller since the electrical swivel and the angle meter shares the same axis of rotation.

In an implementation form of a rotator according to the first aspect, the electrical swivel and the angle meter are arranged in a common housing inside the rotor.

An advantage with this implementation form is easier mounting of the electrical swivel and the angle meter in the rotor. This also means easier dismounting of the electrical swivel and the angle meter, e.g. for service or repair. Further, by having a common housing the electrical swivel and the angle meter are better protected from hydraulic fluid due to a more seamless protective design of the common housing. The common housing also provides a cost-effective solution.

In an implementation form of a rotator according to the first aspect, the hydraulic swivel is arranged axially above the electrical swivel and/or the angle meter inside the rotor.

In an implementation form of a rotator according to the first aspect, the hydraulic swivel is axially aligned with the electrical swivel and/or the angle meter inside the rotor along an axis of rotation of the rotator.

An advantage with this implementation form is that the radial extension of the rotator can be made smaller since the hydraulic swivel shares the same axis of rotation with the electrical swivel and the angle meter.

In an implementation form of a rotator not covered by the invention, the rotator comprises a hydraulic conduit extending inside the rotor from the hydraulic swivel to a hydraulic coupling arranged on an underside of the rotator.

The hydraulic conduit may extend radially outside of the electrical swivel and/or the angle meter inside the rotor.

An advantage with this implementation form is that it is possible to arrange the electrical swivel and/or the angle meter in the centre of the rotor and still have a low building height of the rotator.

In an implementation form of a rotator according to the first aspect, the rotator comprises
torque transfer means arranged radially around a section of the rotor which axially extends outside of the stator.

An advantage with this implementation form is that the torque transfer means transfers load such that the loads at the bearings between the stator and the rotor are mitigated.

In an implementation form of a rotator according to the first aspect, the section of the rotor axially extends outside of the stator in the lower part of the rotator.

Aspects of the invention also relates to an arrangement comprising a rotator according to embodiments of the invention and a jib-carried tool.

The appended drawings are intended to clarify and explain different embodiments of the invention in which:.

<FIG> shows an example of a crane arm <NUM> and a rotator <NUM> attached to the crane arm <NUM>, e.g. via a universal joint/coupling also known as a cardan joint/coupling. A jib-carried tool <NUM> in the form of a harvester for harvesting trees is attached to the rotator <NUM>. A grapple is another non-limiting example of a jib-carried tool. Other types of tools can also be used.

The tool and possible objects held by the tool makes up an external load which is to be carried by the rotator. Non-limiting examples are a harvester carrying a log, and a grapple and metal scrap.

With reference to <FIG> and <FIG> a rotator <NUM> for a tool according to embodiments of the invention are herein disclosed. The rotator <NUM> is in <FIG> shown in a first cross section view in a first line B-B whilst in <FIG> shown in a second cross section view in a second line C-C. The rotator <NUM> has an axial extension and a radial extension as illustrated in <FIG>.

The rotator <NUM> comprises a stator <NUM> and a rotor <NUM> which is rotatably arranged inside the stator <NUM>. The rotor <NUM> comprising a radial bearing <NUM> having a first axial extension a1 in the rotator <NUM> as shown in <FIG>. The rotator <NUM> further comprises a separate bearing <NUM> arranged radially outside the rotor <NUM> and the separate bearing <NUM> is configured to carry an external load of the rotator <NUM>. The rotator <NUM> further comprises an electrical swivel <NUM> and/or an angle meter <NUM> arranged inside the rotor <NUM>. The electrical swivel <NUM> and/or the angle meter <NUM> at least partially extends axially in the first axial extension a1 in the rotator <NUM>. Thereby, a compact rotator is provided having a low building height, i.e. a low axial extension.

The electrical swivel <NUM> can herein be understood as a device or an arrangement that can provide electrical power at and through a rotational interface, e.g. between the stator <NUM> and the rotor <NUM>. It is therefore also disclosed an upper electrical cable <NUM> and a lower electrical cable <NUM> connected to the electrical swivel <NUM>. However, the rotator can comprise one or more upper electrical cables <NUM> and one or more lower electrical cables <NUM> even though only one is shown in the Figs. The electrical cables can be arranged for electrical power transfer or for communication.

The upper electrical cable <NUM> can hence be connected to a power source (not shown) which feeds electrical power or to a first communication device (not shown). The lower electrical cable <NUM> can be connected to one or more applications (not shown) in the tool <NUM> that consumes electrical power or arranged for electrical communication (e.g. via a CAN bus) in the form of one or more second communication devices (not shown) configured to communicate with one or more first communication devices. Non-limiting examples of such applications are processors, sensors, camera, etc..

The angle meter <NUM> can herein be understood as a device or an arrangement that indicates or provides a (relative) rotation between the rotor <NUM> and the stator <NUM>. The rotation can be given in an angle hence the name of the device. The indication of the rotation or the angle can be used in a number of different applications. For example, the rotation or the angle can be used for controlling the rotator <NUM> itself. Another exemplary application is for controlling the tool <NUM>. Yet another application is for controlling the crane arm <NUM>. Yet another application is for controlling the machine or vehicle on which the crane arm is attached. Therefore, the angle meter <NUM> may be communicatively coupled to a control arrangement (not shown). The communication between the angle meter <NUM> and the control arrangement may be performed using wireless and/or wired communications according to known communication protocols. For example, conventional communication buses, such as CAN buses, may be used. Further, the angle meter <NUM> can be powered by the electrical swivel <NUM> via a power cable. Also, the electrical swivel <NUM> may provide one or more signal cables to the angle meter <NUM> for wired communications.

In embodiments of the invention, the stator <NUM> may comprise an upper stator part 102a, a lower stator part 102c and a stator ring 102b arranged between the upper stator part 102a and the lower stator part 102c as shown in <FIG>. The stator ring 102b may comprise a cam curve of a hydraulic motor, such as a vane motor or a piston motor. The cam curve may define one or more hydraulic chambers of the hydraulic motor.

Furthermore, the radial bearing <NUM> of the rotor <NUM> is due to the fact that the rotor <NUM> has to be held in its position in relation to the axis of rotation A and the stator <NUM>. The radial bearing <NUM> of the rotor may therefore comprise an upper radial bearing <NUM> which radially abuts the upper stator part 102a and a lower radial bearing <NUM> which radially abuts the lower stator part 102c which is also shown in the Figs.

The separate bearing <NUM> can be an arrangement having an outer ring <NUM> attached to a lower link <NUM> which is arranged to be attached to the tool <NUM>. The separate bearing <NUM> has an inner ring <NUM> attached to the upper stator part 102a. In between the outer ring <NUM> and the inner ring <NUM> a ball bearing <NUM> is arranged. The separate bearing <NUM> can hence be a slewing bearing.

In embodiments of the invention, the separate bearing <NUM> is arranged axially between the upper radial bearing <NUM> and the lower radial bearing <NUM> of the rotor <NUM> as shown in <FIG> and <FIG>.

In embodiments of the invention, the separate bearing <NUM> at least partially extends axially in the first axial extension a1 in the rotator <NUM> which implies even more compact rotator <NUM> design in its axial extension.

In embodiments of the invention, the rotator <NUM> comprises one or more hydraulic chambers 106a, 106b,. , 106n arranged between the rotor <NUM> and the stator <NUM>. In <FIG> two hydraulic chambers 106a, 106b are shown. Each hydraulic chamber 106n has a second axial extension a2 in the rotator <NUM> which is different from the first axial extension a1 and less than the first axial extension a1, i.e. shorter. In such embodiments the electrical swivel <NUM> and/or the angle meter <NUM> at least partially extends axially in the second axial extension a2 in the rotator <NUM>. Thereby, an even more compact rotator design is provided.

Further, in embodiments of the invention, also the separate bearing <NUM> at least partially extends axially in the second axial extension a2 in the rotator <NUM> as shown in <FIG>. Moreover, the separate bearing <NUM> may be arranged radially outside the one or more hydraulic chambers 106a, 106b,. , 106n which is also illustrated in <FIG>. By having the separate bearing <NUM> radially outside the hydraulic chambers 106a, 106b,. , 106n a compact design can be provided.

The rotator <NUM> also comprises attachment means for attaching the rotator <NUM> to a crane arm. Many different attachment means are known and can be used and in the Figs. the attachment means are attachment ears <NUM> comprising through holes <NUM> through which the latter a coupling pin (not shown) may be inserted. The rotator <NUM> may also be attached to the crane arm via one or more links, such as a braking link, universal joint/coupling, etc..

Moreover, the rotator <NUM> comprises swivel channels <NUM> for providing hydraulic fluid to one or more hydraulic applications of the tool <NUM> and seals/gaskets <NUM> for sealing so as to prevent leakage of hydraulic fluid.

<FIG> and <FIG> shows a close up view of the rotator <NUM> in the first cross section view (B-B) and the second cross section view (C-C), respectively.

In embodiments of the invention and with reference to <FIG> and <FIG>, the rotator <NUM> further comprises a hydraulic swivel <NUM> which is arranged inside the rotor <NUM>. The hydraulic swivel <NUM> also at least partially extends axially in the first axial extension a1 in the rotator <NUM>. For even more compact design in embodiments of the invention the hydraulic swivel <NUM> at least partially extends axially in the second axial extension a2 in the rotator <NUM> since the second axial extension a2 is less than the first axial extension a1.

The hydraulic swivel <NUM> can herein be understood as a device or an arrangement that is arranged to provide hydraulic fluid to one or more hydraulic applications in the tool <NUM> at or through a rotational interface. Therefore, the hydraulic swivel <NUM> can have upper hydraulic conduit (not shown) connected to a hydraulic source which feeds hydraulic fluid and lower hydraulic conduit (see <FIG> and <FIG>) connected to the one or more hydraulic applications in the tool <NUM>. Usually the rotator <NUM> also comprises hydraulic return conduits which is not shown in the Figs.

It should also be noted that the rotator <NUM> may comprise both the electrical swivel <NUM> and the angle meter <NUM> in the same application, i.e. in the same rotator <NUM>. Therefore, in embodiments of the invention, the angle meter <NUM> may be arranged axially above the electrical swivel <NUM> inside the rotor <NUM> as disclosed in the Figs.

The electrical swivel <NUM> and the angle meter <NUM> may be axially aligned with each other inside the rotor <NUM> along the axis of rotation A of the rotator <NUM> which is illustrated in <FIG>. Said axis of rotation A can be considered as a centre axis around which the rotor <NUM> rotates inside the stator <NUM>. The rotation can be clockwise and anti-clockwise.

As further noted from <FIG> and <FIG>, the electrical swivel <NUM> and the angle meter <NUM> may be arranged in a common housing <NUM> inside the rotor <NUM>. The common housing <NUM> may be made of metal, plastic, or any other suitable material. The electrical swivel <NUM> and the angle meter <NUM> may also be axially aligned with each other inside the common housing <NUM>. The angle meter <NUM> may by fully enclosed inside the common housing <NUM> whilst the electrical swivel <NUM> is partially arranged inside the common housing <NUM>.

In embodiments not shown in the Figs. the rotator <NUM> may comprise an opening at the underside of the rotor <NUM>. The opening may be connected to a hollow structure inside the rotor and the hollow structure may be arranged to receive the common housing <NUM> comprising the electrical swivel <NUM> and the angle meter <NUM> in operation. Therefore, the common housing <NUM> can be taken out of the rotor <NUM> through the opening for service and/or repair of the electrical swivel <NUM> and the angle meter <NUM> and thereafter put back. Hence, service and/or repair is made much easier with such design.

In case the rotator <NUM> comprises a hydraulic swivel <NUM> mentioned hydraulic swivel <NUM> may be axially arranged above the electrical swivel <NUM> and/or the angle meter <NUM> inside the rotor <NUM> which is shown in the Figs. Therefore, the hydraulic swivel <NUM> may also be axially aligned with the electrical swivel <NUM> and/or the angle meter <NUM> inside the rotor <NUM> along the axis of rotation A of the rotator <NUM>.

Moreover, with reference to <FIG> the rotator <NUM> may comprises a hydraulic conduit <NUM> which extends inside the rotor <NUM> from the hydraulic swivel <NUM> to a hydraulic coupling <NUM> arranged on an underside of the rotator <NUM> closest to the tool <NUM>. The hydraulic coupling <NUM> may be arranged to couple the hydraulic conduit <NUM> with one or more hydraulic hoses (not shown) arranged to feed one or more hydraulic applications in the tool <NUM>.

Returning back to <FIG>, the rotator <NUM> may also comprise torque transfer means <NUM> arranged radially around a section of the rotor <NUM> which axially extends outside of the stator <NUM>. The torque transfer means <NUM> transfer load such that the loads at the bearings between the stator <NUM> and the rotor <NUM> are mitigated. The section of the rotor <NUM> axially extends outside of the stator <NUM> in the lower part of the rotator <NUM>.

<FIG> shows the rotator <NUM> in a first exterior view related to the first cross section view (B-B) and in a second exterior view related to the second cross section view (C-C), respectively. The attachment means <NUM>, <NUM> are clearly shown in <FIG>.

<FIG> shows the rotator <NUM> in a first perspective view and a second perspective view respectively. The rotator <NUM> comprises attachment means for attaching a tool <NUM> to the rotator <NUM>. Said attachment means may be a lower link <NUM> as previously explained but is not limited thereto. The lower link <NUM> may comprise receiving means for receiving bolts and thereby being attaching the tool <NUM> to the rotator <NUM>.

<FIG> also shows an arrangement of hydraulic couplings <NUM> for feeding the hydraulic motor and/or the hydraulic swivel <NUM>.

Claim 1:
A rotator (<NUM>) for a tool (<NUM>), the rotator (<NUM>) comprising:
a stator (<NUM>);
a rotor (<NUM>) rotatably arranged inside the stator (<NUM>), the rotor (<NUM>) comprising a radial bearing (<NUM>) having a first axial extension (a1) in the rotator (<NUM>);
a separate bearing (<NUM>) arranged radially outside the rotor (<NUM>), the separate bearing (<NUM>) being configured to carry an external load of the rotator (<NUM>);
one or more hydraulic chambers (106a, 106b,..., 106n) arranged between the rotor (<NUM>) and the stator (<NUM>), each hydraulic chamber (106n) having a second axial extension (a2) in the rotator (<NUM>), wherein the second axial extension (a2) is less than the first axial extension (a1); characterized in that the rotator (<NUM>) further comprises
a hydraulic swivel (<NUM>) and an electrical swivel (<NUM>) and/or an angle meter (<NUM>) arranged inside the rotor (<NUM>), wherein the hydraulic swivel (<NUM>) and the electrical swivel (<NUM>) and/or the angle meter (<NUM>) at least partially extends axially in the second axial extension (a2) in the rotator (<NUM>), and wherein the hydraulic swivel (<NUM>) is axially aligned with the electrical swivel (<NUM>) and/or the angle meter (<NUM>) inside the rotor (<NUM>) along the axis of rotation (A) of the rotator (<NUM>).