Patent Publication Number: US-2023138156-A1

Title: Rotator for a tool

Description:
TECHNICAL FIELD 
     The invention relates to a rotator for a tool, such as a jib-carried tool. 
     BACKGROUND 
     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. 
     SUMMARY 
     An objective of embodiments of the invention is to provide a solution which mitigates or solves the drawbacks and problems of conventional solutions. 
     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:
     a stator;   a rotor rotatably arranged inside the stator, the rotor comprising a radial bearing having a first axial extension in the rotator;   a separate bearing arranged radially outside the rotor, the separate bearing being configured to carry an external load of the rotator; and   an electrical swivel and/or an angle meter arranged inside the rotor, wherein the electrical swivel and/or the angle meter at least partially extends axially in the first axial extension in the rotator.   

     Hence, the rotator may comprise an electrical swivel, an angle meter, or an electrical swivel and an angle meter. 
     That the electrical swivel and/or an angle meter at least partially extends axially in the first axial extension can be understood that the said electrical swivel and/or an angle meter has at least one part/section that extends or is inside the first axial extension but can have another parts/section that does not extend or is inside the first axial extension. 
     The tool may be a jib-carried tool. 
     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. 
     In an implementation form of a rotator according to the first aspect, the rotator comprises 
     one or more hydraulic chambers arranged between the rotor and the stator, each hydraulic chamber having a second axial extension in the rotator, wherein the second axial extension is less than the first axial extension; and wherein   the electrical swivel and/or the angle meter at least partially extends axially in the second axial extension in the rotator.   

     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. 
     An advantage with this implementation form is that the rotator can be made even more compact in its axial extension. 
     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 is that the rotator can be made even more compact in its axial extension. 
     In an implementation form of a rotator according to the first aspect, the rotator comprises 
     a hydraulic swivel arranged inside the rotor; and wherein   the hydraulic swivel at least partially extends axially in the first 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. 
     In an implementation form of a rotator according to the first aspect, the hydraulic swivel at least partially extends axially in the second 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. 
     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 according to the first aspect, 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. 
     Further applications and advantages of the embodiments of the invention will be apparent from the following detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The appended drawings are intended to clarify and explain different embodiments of the invention in which: 
         FIG.  1    shows a rotator in a first cross section view B-B according to an embodiment of the invention; 
         FIG.  2    shows the rotator in  FIG.  1    in a second cross section view C-C which is perpendicular to the first cross section view; 
         FIG.  3    shows a close up view of the rotator in the first cross section view; 
         FIG.  4    shows a close up view of the rotator in the second cross section view; 
         FIG.  5    shows the rotator in a first exterior view related to the first cross section view B-B; 
         FIG.  6    shows the rotator in a second exterior view related to the second cross section view C-C; 
         FIG.  7    shows the rotator in a first perspective view; 
         FIG.  8    shows the rotator in a second perspective view; and 
         FIG.  9    illustrates an arrangement of crane arms, a rotator and a jib-carried tool. 
     
    
    
     DETAILED DESCRIPTION 
       FIG.  9    shows an example of a crane arm  300  and a rotator  100  attached to the crane arm  300 , e.g. via a universal joint/coupling also known as a cardan joint/coupling. A jib-carried tool  200  in the form of a harvester for harvesting trees is attached to the rotator  100 . 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  FIGS.  1  and  2    a rotator  100  for a tool according to embodiments of the invention are herein disclosed. The rotator  100  is in  FIG.  1    shown in a first cross section view in a first line B-B whilst in  FIG.  2    shown in a second cross section view in a second line C-C. The rotator  100  has an axial extension and a radial extension as illustrated in  FIG.  1   . 
     The rotator  100  comprises a stator  102  and a rotor  104  which is rotatably arranged inside the stator  102 . The rotor  104  comprising a radial bearing  122  having a first axial extension a1 in the rotator  100  as shown in  FIG.  1   . The rotator  100  further comprises a separate bearing  112  arranged radially outside the rotor  104  and the separate bearing  112  is configured to carry an external load of the rotator  100 . The rotator  100  further comprises an electrical swivel  108  and/or an angle meter 116 arranged inside the rotor  104 . The electrical swivel  108  and/or the angle meter 116 at least partially extends axially in the first axial extension a1 in the rotator  100 . Thereby, a compact rotator is provided having a low building height, i.e. a low axial extension. 
     The electrical swivel  108  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  102  and the rotor  104 . It is therefore also disclosed an upper electrical cable  132  and a lower electrical cable  134  connected to the electrical swivel  108 . However, the rotator can comprise one or more upper electrical cables  132  and one or more lower electrical cables  134  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  132  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  134  can be connected to one or more applications (not shown) in the tool  200  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 116 can herein be understood as a device or an arrangement that indicates or provides a (relative) rotation between the rotor  104  and the stator  102 . 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  100  itself. Another exemplary application is for controlling the tool  200 . Yet another application is for controlling the crane arm  300 . Yet another application is for controlling the machine or vehicle on which the crane arm is attached. Therefore, the angle meter 116 may be communicatively coupled to a control arrangement (not shown). The communication between the angle meter 116 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 116 can be powered by the electrical swivel  108  via a power cable. Also, the electrical swivel  108  may provide one or more signal cables to the angle meter 116 for wired communications. 
     In embodiments of the invention, the stator  102  may comprise an upper stator part  102   a , a lower stator part  102   c  and a stator ring  102   b  arranged between the upper stator part  102   a  and the lower stator part  102   c  as shown in  FIG.  1   . The stator ring  102   b  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  122  of the rotor  104  is due to the fact that the rotor  104  has to be held in its position in relation to the axis of rotation A and the stator  102 . The radial bearing  122  of the rotor may therefore comprise an upper radial bearing  124  which radially abuts the upper stator part  102   a  and a lower radial bearing  126  which radially abuts the lower stator part  102   c  which is also shown in the Figs. 
     The separate bearing  112  can be an arrangement having an outer ring  142  attached to a lower link  150  which is arranged to be attached to the tool  200 . The separate bearing  112  has an inner ring  144  attached to the upper stator part  102   a . In between the outer ring  142  and the inner ring  144  a ball bearing  146  is arranged. The separate bearing  112  can hence be a slewing bearing. 
     In embodiments of the invention, the separate bearing  112  is arranged axially between the upper radial bearing  124  and the lower radial bearing  126  of the rotor  104  as shown in  FIGS.  1  and  2   . 
     In embodiments of the invention, the separate bearing  112  at least partially extends axially in the first axial extension a1 in the rotator  100  which implies even more compact rotator  100  design in its axial extension. 
     In embodiments of the invention, the rotator  100  comprises one or more hydraulic chambers  106   a ,  106   b ,...,  106   n  arranged between the rotor  102  and the stator  102 . In  FIG.  1    two hydraulic chambers  106   a ,  106   b  are shown. Each hydraulic chamber  106   n  has a second axial extension a2 in the rotator  100  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  108  and/or the angle meter 116 at least partially extends axially in the second axial extension a2 in the rotator  100 . Thereby, an even more compact rotator design is provided. 
     Further, in embodiments of the invention, also the separate bearing  112  at least partially extends axially in the second axial extension a2 in the rotator  100  as shown in  FIG.  1   . Moreover, the separate bearing  112  may be arranged radially outside the one or more hydraulic chambers  106   a ,  106   b ,...,  106   n  which is also illustrated in  FIG.  1   . By having the separate bearing  112  radially outside the hydraulic chambers  106   a ,  106   b ,...,  106   n  a compact design can be provided. 
     The rotator  100  also comprises attachment means for attaching the rotator  100  to a crane arm. Many different attachment means are known and can be used and in the Figs. the attachment means are attachment ears  152  comprising through holes  154  through which the latter a coupling pin (not shown) may be inserted. The rotator  100  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  100  comprises swivel channels  128  for providing hydraulic fluid to one or more hydraulic applications of the tool  200  and seals/gaskets  136  for sealing so as to prevent leakage of hydraulic fluid. 
       FIGS.  3  and  4    shows a close up view of the rotator  100  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  FIGS.  3  and  4   , the rotator  100  further comprises a hydraulic swivel  114  which is arranged inside the rotor  104 . The hydraulic swivel  114  also at least partially extends axially in the first axial extension a1 in the rotator  100 . For even more compact design in embodiments of the invention the hydraulic swivel  114  at least partially extends axially in the second axial extension a2 in the rotator  100  since the second axial extension a2 is less than the first axial extension a1. 
     The hydraulic swivel  114  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  200  at or through a rotational interface. Therefore, the hydraulic swivel  114  can have upper hydraulic conduit (not shown) connected to a hydraulic source which feeds hydraulic fluid and lower hydraulic conduit (see  FIGS.  1  and  4   ) connected to the one or more hydraulic applications in the tool  200 . Usually the rotator  100  also comprises hydraulic return conduits which is not shown in the Figs. 
     It should also be noted that the rotator  100  may comprise both the electrical swivel  108  and the angle meter 116 in the same application, i.e. in the same rotator  100 . Therefore, in embodiments of the invention, the angle meter 116 may be arranged axially above the electrical swivel  108  inside the rotor  104  as disclosed in the Figs. 
     The electrical swivel  108  and the angle meter 116 may be axially aligned with each other inside the rotor  104  along the axis of rotation A of the rotator  100  which is illustrated in  FIGS.  2 - 4   . Said axis of rotation A can be considered as a centre axis around which the rotor  104  rotates inside the stator  102 . The rotation can be clockwise and anti-clockwise. 
     As further noted from  FIGS.  3  and  4   , the electrical swivel  108  and the angle meter 116 may be arranged in a common housing  130  inside the rotor  104 . The common housing  130  may be made of metal, plastic, or any other suitable material. The electrical swivel  108  and the angle meter 116 may also be axially aligned with each other inside the common housing  130 . The angle meter 116 may by fully enclosed inside the common housing  130  whilst the electrical swivel  108  is partially arranged inside the common housing  130 . 
     In embodiments not shown in the Figs. the rotator  100  may comprise an opening at the underside of the rotor  104 . The opening may be connected to a hollow structure inside the rotor and the hollow structure may be arranged to receive the common housing  130  comprising the electrical swivel  108  and the angle meter 116 in operation. Therefore, the common housing  130  can be taken out of the rotor  104  through the opening for service and/or repair of the electrical swivel  108  and the angle meter 116 and thereafter put back. Hence, service and/or repair is made much easier with such design. 
     In case the rotator  100  comprises a hydraulic swivel  114  mentioned hydraulic swivel  114  may be axially arranged above the electrical swivel  108  and/or the angle meter 116 inside the rotor  104  which is shown in the Figs. Therefore, the hydraulic swivel  114  may also be axially aligned with the electrical swivel  108  and/or the angle meter 116 inside the rotor  104  along the axis of rotation A of the rotator  100 . 
     Moreover, with reference to  FIG.  4    the rotator  100  may comprises a hydraulic conduit  118  which extends inside the rotor  104  from the hydraulic swivel  114  to a hydraulic coupling  120  arranged on an underside of the rotator  100  closest to the tool  200 . The hydraulic coupling  120  may be arranged to couple the hydraulic conduit  118  with one or more hydraulic hoses (not shown) arranged to feed one or more hydraulic applications in the tool  200 . 
     Returning back to  FIG.  3   , the rotator  100  may also comprise torque transfer means 110 arranged radially around a section of the rotor  104  which axially extends outside of the stator  102 . The torque transfer means 110 transfer load such that the loads at the bearings between the stator  102  and the rotor  104  are mitigated. The section of the rotor  104  axially extends outside of the stator  102  in the lower part of the rotator  100 . 
       FIGS.  5  and  6    shows the rotator  100  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  152 ,  154  are clearly shown in  FIGS.  5  and  6   . 
       FIGS.  7  and  8    shows the rotator  100  in a first perspective view and a second perspective view respectively. The rotator  100  comprises attachment means for attaching a tool  200  to the rotator  100 . Said attachment means may be a lower link  150  as previously explained but is not limited thereto. The lower link  150  may comprise receiving means for receiving bolts and thereby being attaching the tool  200  to the rotator  100 . 
       FIG.  7    also shows an arrangement of hydraulic couplings  160  for feeding the hydraulic motor and/or the hydraulic swivel  114 . 
     Finally, it should be understood that the invention is not limited to the embodiments described above, but also relates to and incorporates all embodiments within the scope of the appended independent claims.