CA1103621A - Twin type slewing crane - Google Patents
Twin type slewing craneInfo
- Publication number
- CA1103621A CA1103621A CA353,312A CA353312A CA1103621A CA 1103621 A CA1103621 A CA 1103621A CA 353312 A CA353312 A CA 353312A CA 1103621 A CA1103621 A CA 1103621A
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- crane
- cranes
- bearing
- central axis
- base plate
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Abstract
ABSTRACT OF THE DISCLOSURE
A twin-type slewing crane comprising an upright foundation with a ring gear secured thereon and having a generally vertical axis. A generally horizontal base plate is mounted on the foundation. Two individual cranes, each having a luffing jib with means including a hoisting rope running from a winch of that crane to a jib thereof for raising and lowering the jib, are also provided. A support is provided for each crane, each mounting a respective crane for rotation about the central axis at the same distance from the central axis as one another. A rotating mechanism is provided for each crane and projects therefrom into mesh-ing relationship with the ring gear, whereby operation of the rotating mechanism of at least one of the cranes propels at least that respective crane about the said central axis.
A central axle is coaxially disposed on the central axis and extends upwards from the base plate. Also provided are two axially intercalated sets of two axially spaced bearings.
Each bearing has an inner race mounted on the axle and one set has an outer race of each bearing thereof mounted on the support of one of the cranes and the other set has an outer race of each bearing thereof mounted on the support of the other of the cranes. An anti-tipping roller is provided bet-ween the supporting means of each of the cranes and the base plate.
A twin-type slewing crane comprising an upright foundation with a ring gear secured thereon and having a generally vertical axis. A generally horizontal base plate is mounted on the foundation. Two individual cranes, each having a luffing jib with means including a hoisting rope running from a winch of that crane to a jib thereof for raising and lowering the jib, are also provided. A support is provided for each crane, each mounting a respective crane for rotation about the central axis at the same distance from the central axis as one another. A rotating mechanism is provided for each crane and projects therefrom into mesh-ing relationship with the ring gear, whereby operation of the rotating mechanism of at least one of the cranes propels at least that respective crane about the said central axis.
A central axle is coaxially disposed on the central axis and extends upwards from the base plate. Also provided are two axially intercalated sets of two axially spaced bearings.
Each bearing has an inner race mounted on the axle and one set has an outer race of each bearing thereof mounted on the support of one of the cranes and the other set has an outer race of each bearing thereof mounted on the support of the other of the cranes. An anti-tipping roller is provided bet-ween the supporting means of each of the cranes and the base plate.
Description
~1~136Zl The present invention relates to an improved twin-type slewing crane.
Twin-type slewing cranes are used for handling loads on board ship. The individual cranes together make up the twin crane being either used singly to load and unload indi-vidual holds, or in combination for moving heavy freight.
Ordinary twin slewing cranes have a large mass (weight) and are expensive as well, since each single crane is constructed and arranged in such a way as to allow an individual slewing motion. Each crane is thus rotatably arranged on a common platform which itself can be rotated around a foundation firmly anchored in the hull of the ship.
Such cranes have three slewing rims, three gear rings, three slewing mechanisms and, in addition, a large common platform.
This type of construction makes for complex and expensive assembly procedures and leads to high costs of transport, assembly, inspection and maintenance.
Another type of twin slewing crane using only a single gear ring and a slewing rim is known. These rim, or bearing, however, are constructed so as to provide a double pivoting link, that is, two bearing functions are combined so that the middle race of the bearing is attached both to the foundation of the crane and to the gear ring, while the outer race of the bearing is connected by a collar arm to one crane, and the inner race is connected, by another collar arm, to the other crane.
This type of bearing is very special, and since it produces a slewing rim of very large diameter it is extremely expensive and difficult to repair or replace if it is damaged. In addi-tion to this, the positions o~ the collar arms in relation to the bearing require different mechanical constructions in each crane while at the same time the slewing mechanisms in each C' ~
3~Zl crane must be mounted differently. In one, the driving motor is mounted upwards, and in the other it is mounted downwards.
Disadvantages are complications of construction and assembly of the mechanism, and the fact that the driving motors must be differently designed to allow drainage of condensing water.
The invention concerns a duplex slewing crane where both cranes are located at the same distance from a common vertical axis, where both are provided with a luffing jib and, in relation to one another, are able to function within a large angle of rotation, and where, whenever necessary, both cranes are able to work together and thus are adjustable to any given angle of rotation.
A feature of the present invention is to solve the problem of combining two mechanically identical cranes whose luffing jibs have the same maximum and minimum out-reach, two slewing machineries and one slewing rim, and to simplify the construction of a supporting bearing, safe to rotate and tip, so that the assembly becomes simple and as cheap as possible while the desired functions are achieved in operation of both cranes.
According to a broad aspect of the present inven-tion, there is provided a twin-type slewing crane comprising an upright foundation with a ring gear secured thereon and having a generally vertical axis. A generally horizontal base plate is mounted on the foundation. Two individual cranes, each having a luffing jib with means including a hoisting rope running from a winch of that crane to a jib thereof for raising and lowering the jib, are also provided. A supporting means is provided for each crane, each mounting a respective crane for rotation about the central axis at the same distance from the central axis as one another. A rotating mechanism is provided for each crane and projects therefrom into meshing 6Zl relationship with the ring gear, whereby operation of the rotating mechanism of at least one of the cranes propels at least that respective crane about the said central axis. A
central axle is coaxially disposed on the central axis and extends upwards from the base plate. Also provided are two axially intercalated sets of two axially spaced bearings.
Each bearing has an inner race mounted on the axle and one set has an outer race of each bearing thereof mounted on the supporting means of one of the cranes and the other set has an outer race of each bearing thereof mounted on the supporting means of the other of the cranes. An anti-tipping roller means is provided between the supporting means of each of the cranes and the base plate.
The following drawings illustrate a preferred embo-diment of the invention showing the construction of a twin slewing crane where:
FIGURE 1 is a side view, partly in section, of a first version of a twin slewing crane as per this invention:
FIGURE 2 is a plan view of Figure 1, the cranes being illustrated singly or together:
FIGURES 3, 4 and 5 are side views,partly in section, of second, third and fourth versions of a duplex slewing crane as per this invention:
and FIGURE 6 shows, in highly simplified form, the under-lying principles of a variant of the sup-porting structures of the twin crane as shown in Figures 1, 3, 4 and 5.
- 3` ~
~gl 3621 In the first version of Figure 1, a foundation 1 having a conical head 2, and provided with an end plate 3, is shown mounted on the hull of a ship, not illustrated here, On this end plate 3 is mounted an outer race 4 with a gear ring 5, to a simple ball or roller-bearing connection, or so-called slewing rim, generally designated 6. The inner race 7 of this slewing rim 6, mounted on the outer race 4, is securely screwed to a base plate 8. To this base plate 8 are attached a hollow vertical bearing-mounted axle 9 and a primary supporting structure 10 with a vertical supporting plate 11 to which the first crane 12 is attached. The axle 9 runs through a vertical, circular hole 13 in the supporting structure 10 to which it is here - 3a -1~36Zl attached, This allows the axle 9 to rotate simultaneously with the inner race 7 of the slewing rim 6 and the base plate 8.
Bolts, not illustrated here, are used to connect the supporting plate 11 with a vertical back plate 14 on the crane 12. This crane 12 is provided with a slewing machinery 15 which, by means of a gear 16, extending downwards and rotating against the gear ring 5, slews the crane 12 around the slewing axis o~
the base of the crane 12, here designated 17, In the version illustrated here, the crane 12 is equipped with a luffing jib 18, luffing rope 19, luffing machinery20, hoisting wire 21 and a hoisting machinery 22, The primary supporting structure 10 is provided with upper and lower horizontal recesses, 23 and 24, in which the secondary supporting structure 27, also designated slewing structure, provided with recess 28 and rotating round the vertical bearing-mounted axle 9, is mounted on upper and lower roller bearings 25 and 26. The slewing structure 27 is pro-vided with a vertical plate 11' supporting the second crane 12'. Like the first crane 12, this supporting plate 11' is bolted into a back plate 14' fastened to the back of the second crane 12'. The slewing structure 27 of the second crane 12' is thus mounted on the supporting structure 10 of the first crane 12 by means of the vertical bearing-mounted axle 9.
Both supporting structures 10 and 27 are located at equal heights and above the gear ring 5, and also each of the cranes 12 and 12'. The construction of the second crane 12' is identical with that of the first crane, and through the action of the slewing machinery 15' and its gear 16', which, like the first crane 12 rotates against the gear ring ~, it can be made to rotate relative to the first crane 12 and the vertical bearin~
mounted axle 9, and thereby around the slewing axis 17 of the crane base as well.
11~36Zl A connecting tube 29 runs through the vertical bearing-mounted axle 9. The lower end of this tube is attached to a bracket 30 fastened to the end plate 3, while the upper end is mounted in the vertical bearing-mounted axle 9 by means of a bearing 31. The tube 29 comprises a slip-ring device 32 for the provision of electricity to the cranes 12 and 12'.
In order to displace the second crane 12' when nece-ssary, one or more travelling wheels 33 are provided and moving on a circular track attached to the base plate 8.
Figure 2 shows how each crane 12 and 12' can work individually and how the second crane 12' can be manoeuvred in-to a position - shown here in dotted lines - next to the first crane 12 enabling both to wor~ together as a twin slewing crane.
The angle of rotation of the second crane 12' relative to the first crane 12 is at least 180. If both cranes are slewed simultaneously the angle of rotation is unlimited. If both are working together, the cranes 12 and 12' being locked into position beside one another (not illustrated here) and the rotation is unlimited.
me supporting structure 10 and slewing structure 27 are built so that they form an angle in order to be able to bring the cranes 12 and 12' into a position where they are roughly parallel with each other andto achieve a suitable dis-tance ~etween the load hooks. The angle ~ between the centre line 35 of the first luffing jib 18 and the centre line 36 of the supporting structure, and between the centre line 37 of the second luffing jib 18' and the centre line 38 of the slewing structure 27, is thus less than 90.
If both cranes are to be operated simu~taneously,the luffing machinery 20 and 20' and the hoisting machinery 2~ and 22' must be synchronized so that the movement of the jibs and ~3~Zl hoisting ropes are equal. The slewing machinery 15 and 15', too, must be synchronized in order to allow the simultaneous rotation of the cranes 12 and 12', unless one machinery is powerful enough to be able to slew both cranes alone. This twin slewing crane is thus capable of handling loads twice as heavy as the maximum working load of a single crane.
Figure 3 shows another version of a twin slewing crane, from which it is apparent that the bearing-mounted axle 9 attached to the base plate 8, illustrated in Figure 1, has been replaced by a hollow, vertical, articulated axle 39 attached to the primary supporting structure 10 but not to the base plate 40. In this version, the function of the articulated axle 39 is simply to serve as a hinged axle on which the second crane 12' is suspended by means of bearings 25 and 26, and around which the second crane 12' can be made to rotate relative to the first crane 12.
The version to be used is determined by the mechanical dimensions of the crane with regard to operational loads and stress.
Figure 4 shows a third version of a twin slewing crane, from which it is apparent that the articulated axle 39, illustrated in Figure 3, has been replaced by upper and lower tubular stubs, 41 and 42. These are attached to the supporting structure 10 but not to the base plate 40. The tubular stubs function as pivot pins on which the second crane 12' is suspended by means of bearings 25 and 26 and around which the second crane 12' can be made to rotate relative to the first crane 12.
Figure 5 shows a fourth version of a twin slewing crane, from which it is apparent that, unlike Figures 1, 3 and 4, there is no slewing rim, that both cranes 12 and 12' are suspended on a hollow, non-rotating vertical column axle 43 and that the base plate, here designated 44, is fixed to the foundation 45 of the crane.
The foundation 45 of the crane has a conical head 46, a twin supporting plate 47 and the base plate 44 just mentioned.
These two plates are rigidly mounted and cannot rotate. A gear ring 48 is mounted on the foundation of the crane 45, into which the gears, 16 and 16', of the slewing machinery 15 and 15', of the individual cranes 12 and 12' mesh. The upper end of the vertical column axle 43 is covered by a plate 49 supporting a slip-ring device 32 and is fitted with a bearing flange 50, located at some distance away from the lower end of the axle, and a supporting flange 51 with a stub axle 52 at its lower end.
Stability of the vertical column axle 43 is achieved by fixing the supporting flange 51 and stub axle 52 firmly to the support-ing plate, while the bearing flange 50 is attached to the base plate 44. The primary supporting structure 55, mounted on the axle 43 by means of upper and lower roller bearings 53 and 54, carries a vertical supporting plate 56 to which the first ~rane 12 is attached. This supporting plate 56 is fastened by bolts (not illustrated here) to a vertical plate 14 on the back of the crane 12. The primary supporting structure 55 is pro-vided with upper and lower horizontal recesses, 57 and 58, in which the secondary supporting structure 61, which rotates around the vertical column axle 43, is mounted on upper and lower roller bearings 59 and 60. The secondary supporting structure 61 is provided with upper and lower horizontal recesses 62 and 63 respectively, into which the roller bearings 53 and 54 mentioned above, running around the vertical column axle ~3 ~0 are fitted. The secondary supporting structure 61 has a verti-cal plate 56 which carries the second crane 12' and which, like the first crane 12, is fastene~ by bolts to a plate 14' attache~
to the back of the second crane 12'. The construction is other-wise the same as sho~ in Figures 1, 3 and 4. The cranes 12 and 12', working both singly and together, move in the same way as those shown in the first version.
In order to offset the downward pull of the first and second cranes 12 and 12', each is provided, if their size should make it necessary, with one or more travelling wheels, 33 and 33', moving on a circular track 64 attached to the base plate 44.
The version shown in Figure 5 has the advantage that instead of the large slewing rim with two smaller roller bearings as used in the first, second and third versions illustrated in Figures 1, 3 and 4, four small roller bearings can be used which do away with the difficulty of obtaining an expensive slewing rim manufactured in small series only, and which allow roller bearings to be used which can be manufactured in large series and are ~ence cheaper and more standardized.
Figure 6 shows, in highly simplified form, the funda-mental principle of a variant of the supporting structures ofth~ cranes 12 and 12'. The structures, here designated 65 and 66, are provided with vertical supporting plates 67 and 67' which at their lower end have horizontal projections, 68 and 68'. 8y this arrangement, the vertical plates 14 and 14' on the back of the cranes 12 and 12' can be bolted to the support-ing plates 67 and 67' while the bottom of the cranes can be bolted to the projections 68 and 68', thus increasing the strength of the attachment of the cranes to their supporting structures 65 and 66. In certain smaller versions of this crane type, bolting the cranes to the projections only wou1d be sufficient.
~19;~6Zl Some of the advantages offered by twin slewing cranes of the type described herein may be summarized as follows:
By using a vertical bearing axle, an articulated axle or tubular axle stubs co~bined with the structures supporting each crane, and by attaching the crane to a base plate which can be rotated on a slewing rim in versions 1, 2 and 3 a single slewing rim and two mechanically identical cranes without individual slewing rim or gear rings can be used.
By using a simple vertical column axle, in version 4, a number of roller bearings and supporting structures to carry the individual cranes, even the single slewing rim mentioned above can be avoided. Here, too, mechanically identical cranes without individual slewing rims can be used.
By eliminating the platform used in conventional cranes the height of this type of twin crane can be decreased.
By eliminating the large size slewing rims and gear rings hitherto used in the construction of the base of single cranes, and by omitting in the platform, the construction is simplified at the same time as building costs and total weight are reduced.
By eliminating all large size slewing rims in the fourth version and instead using more conventional roller bearings, the difficulties associated with obtaining and purchasing expensive special bearings is avoided.
By the method of construction of this twin crane, and by using the slewing machineries of the individual cranes for operation of the cranes either singly or as a pair, the slewing machinery and provision for power supply hitherto used can be avoided, meaning that testing, inspection and maintenance can be more simply carried out.
_ g _ By the method of construction used, costs of transport and assembly on board ship can be reduced as compared with conventional cranes.
Details of design of the examples of the embodiment described herein may be modified within the limits of the claims. Thus, in versions 1, 2 and 3, a recess may be provided in the middle of the supporting structure instead of at its upper and lower ends, and a bearing may be mounted there in-stead. Again, the number of bearings could, e.g. be increased or that the roller bearings replaced by slide bearings, or the supporting structures and slewing structures may be provided with a number of recesses following the principle of the "piano hinge". Another possible modification would be to place the travelling wheels at a greater distance fram the common vertical axis of the crane, under each individual crane, for instance.
This application is a division of Canadian Patent Application Serial ~o. 287,443 filed September 26, 1977.
Twin-type slewing cranes are used for handling loads on board ship. The individual cranes together make up the twin crane being either used singly to load and unload indi-vidual holds, or in combination for moving heavy freight.
Ordinary twin slewing cranes have a large mass (weight) and are expensive as well, since each single crane is constructed and arranged in such a way as to allow an individual slewing motion. Each crane is thus rotatably arranged on a common platform which itself can be rotated around a foundation firmly anchored in the hull of the ship.
Such cranes have three slewing rims, three gear rings, three slewing mechanisms and, in addition, a large common platform.
This type of construction makes for complex and expensive assembly procedures and leads to high costs of transport, assembly, inspection and maintenance.
Another type of twin slewing crane using only a single gear ring and a slewing rim is known. These rim, or bearing, however, are constructed so as to provide a double pivoting link, that is, two bearing functions are combined so that the middle race of the bearing is attached both to the foundation of the crane and to the gear ring, while the outer race of the bearing is connected by a collar arm to one crane, and the inner race is connected, by another collar arm, to the other crane.
This type of bearing is very special, and since it produces a slewing rim of very large diameter it is extremely expensive and difficult to repair or replace if it is damaged. In addi-tion to this, the positions o~ the collar arms in relation to the bearing require different mechanical constructions in each crane while at the same time the slewing mechanisms in each C' ~
3~Zl crane must be mounted differently. In one, the driving motor is mounted upwards, and in the other it is mounted downwards.
Disadvantages are complications of construction and assembly of the mechanism, and the fact that the driving motors must be differently designed to allow drainage of condensing water.
The invention concerns a duplex slewing crane where both cranes are located at the same distance from a common vertical axis, where both are provided with a luffing jib and, in relation to one another, are able to function within a large angle of rotation, and where, whenever necessary, both cranes are able to work together and thus are adjustable to any given angle of rotation.
A feature of the present invention is to solve the problem of combining two mechanically identical cranes whose luffing jibs have the same maximum and minimum out-reach, two slewing machineries and one slewing rim, and to simplify the construction of a supporting bearing, safe to rotate and tip, so that the assembly becomes simple and as cheap as possible while the desired functions are achieved in operation of both cranes.
According to a broad aspect of the present inven-tion, there is provided a twin-type slewing crane comprising an upright foundation with a ring gear secured thereon and having a generally vertical axis. A generally horizontal base plate is mounted on the foundation. Two individual cranes, each having a luffing jib with means including a hoisting rope running from a winch of that crane to a jib thereof for raising and lowering the jib, are also provided. A supporting means is provided for each crane, each mounting a respective crane for rotation about the central axis at the same distance from the central axis as one another. A rotating mechanism is provided for each crane and projects therefrom into meshing 6Zl relationship with the ring gear, whereby operation of the rotating mechanism of at least one of the cranes propels at least that respective crane about the said central axis. A
central axle is coaxially disposed on the central axis and extends upwards from the base plate. Also provided are two axially intercalated sets of two axially spaced bearings.
Each bearing has an inner race mounted on the axle and one set has an outer race of each bearing thereof mounted on the supporting means of one of the cranes and the other set has an outer race of each bearing thereof mounted on the supporting means of the other of the cranes. An anti-tipping roller means is provided between the supporting means of each of the cranes and the base plate.
The following drawings illustrate a preferred embo-diment of the invention showing the construction of a twin slewing crane where:
FIGURE 1 is a side view, partly in section, of a first version of a twin slewing crane as per this invention:
FIGURE 2 is a plan view of Figure 1, the cranes being illustrated singly or together:
FIGURES 3, 4 and 5 are side views,partly in section, of second, third and fourth versions of a duplex slewing crane as per this invention:
and FIGURE 6 shows, in highly simplified form, the under-lying principles of a variant of the sup-porting structures of the twin crane as shown in Figures 1, 3, 4 and 5.
- 3` ~
~gl 3621 In the first version of Figure 1, a foundation 1 having a conical head 2, and provided with an end plate 3, is shown mounted on the hull of a ship, not illustrated here, On this end plate 3 is mounted an outer race 4 with a gear ring 5, to a simple ball or roller-bearing connection, or so-called slewing rim, generally designated 6. The inner race 7 of this slewing rim 6, mounted on the outer race 4, is securely screwed to a base plate 8. To this base plate 8 are attached a hollow vertical bearing-mounted axle 9 and a primary supporting structure 10 with a vertical supporting plate 11 to which the first crane 12 is attached. The axle 9 runs through a vertical, circular hole 13 in the supporting structure 10 to which it is here - 3a -1~36Zl attached, This allows the axle 9 to rotate simultaneously with the inner race 7 of the slewing rim 6 and the base plate 8.
Bolts, not illustrated here, are used to connect the supporting plate 11 with a vertical back plate 14 on the crane 12. This crane 12 is provided with a slewing machinery 15 which, by means of a gear 16, extending downwards and rotating against the gear ring 5, slews the crane 12 around the slewing axis o~
the base of the crane 12, here designated 17, In the version illustrated here, the crane 12 is equipped with a luffing jib 18, luffing rope 19, luffing machinery20, hoisting wire 21 and a hoisting machinery 22, The primary supporting structure 10 is provided with upper and lower horizontal recesses, 23 and 24, in which the secondary supporting structure 27, also designated slewing structure, provided with recess 28 and rotating round the vertical bearing-mounted axle 9, is mounted on upper and lower roller bearings 25 and 26. The slewing structure 27 is pro-vided with a vertical plate 11' supporting the second crane 12'. Like the first crane 12, this supporting plate 11' is bolted into a back plate 14' fastened to the back of the second crane 12'. The slewing structure 27 of the second crane 12' is thus mounted on the supporting structure 10 of the first crane 12 by means of the vertical bearing-mounted axle 9.
Both supporting structures 10 and 27 are located at equal heights and above the gear ring 5, and also each of the cranes 12 and 12'. The construction of the second crane 12' is identical with that of the first crane, and through the action of the slewing machinery 15' and its gear 16', which, like the first crane 12 rotates against the gear ring ~, it can be made to rotate relative to the first crane 12 and the vertical bearin~
mounted axle 9, and thereby around the slewing axis 17 of the crane base as well.
11~36Zl A connecting tube 29 runs through the vertical bearing-mounted axle 9. The lower end of this tube is attached to a bracket 30 fastened to the end plate 3, while the upper end is mounted in the vertical bearing-mounted axle 9 by means of a bearing 31. The tube 29 comprises a slip-ring device 32 for the provision of electricity to the cranes 12 and 12'.
In order to displace the second crane 12' when nece-ssary, one or more travelling wheels 33 are provided and moving on a circular track attached to the base plate 8.
Figure 2 shows how each crane 12 and 12' can work individually and how the second crane 12' can be manoeuvred in-to a position - shown here in dotted lines - next to the first crane 12 enabling both to wor~ together as a twin slewing crane.
The angle of rotation of the second crane 12' relative to the first crane 12 is at least 180. If both cranes are slewed simultaneously the angle of rotation is unlimited. If both are working together, the cranes 12 and 12' being locked into position beside one another (not illustrated here) and the rotation is unlimited.
me supporting structure 10 and slewing structure 27 are built so that they form an angle in order to be able to bring the cranes 12 and 12' into a position where they are roughly parallel with each other andto achieve a suitable dis-tance ~etween the load hooks. The angle ~ between the centre line 35 of the first luffing jib 18 and the centre line 36 of the supporting structure, and between the centre line 37 of the second luffing jib 18' and the centre line 38 of the slewing structure 27, is thus less than 90.
If both cranes are to be operated simu~taneously,the luffing machinery 20 and 20' and the hoisting machinery 2~ and 22' must be synchronized so that the movement of the jibs and ~3~Zl hoisting ropes are equal. The slewing machinery 15 and 15', too, must be synchronized in order to allow the simultaneous rotation of the cranes 12 and 12', unless one machinery is powerful enough to be able to slew both cranes alone. This twin slewing crane is thus capable of handling loads twice as heavy as the maximum working load of a single crane.
Figure 3 shows another version of a twin slewing crane, from which it is apparent that the bearing-mounted axle 9 attached to the base plate 8, illustrated in Figure 1, has been replaced by a hollow, vertical, articulated axle 39 attached to the primary supporting structure 10 but not to the base plate 40. In this version, the function of the articulated axle 39 is simply to serve as a hinged axle on which the second crane 12' is suspended by means of bearings 25 and 26, and around which the second crane 12' can be made to rotate relative to the first crane 12.
The version to be used is determined by the mechanical dimensions of the crane with regard to operational loads and stress.
Figure 4 shows a third version of a twin slewing crane, from which it is apparent that the articulated axle 39, illustrated in Figure 3, has been replaced by upper and lower tubular stubs, 41 and 42. These are attached to the supporting structure 10 but not to the base plate 40. The tubular stubs function as pivot pins on which the second crane 12' is suspended by means of bearings 25 and 26 and around which the second crane 12' can be made to rotate relative to the first crane 12.
Figure 5 shows a fourth version of a twin slewing crane, from which it is apparent that, unlike Figures 1, 3 and 4, there is no slewing rim, that both cranes 12 and 12' are suspended on a hollow, non-rotating vertical column axle 43 and that the base plate, here designated 44, is fixed to the foundation 45 of the crane.
The foundation 45 of the crane has a conical head 46, a twin supporting plate 47 and the base plate 44 just mentioned.
These two plates are rigidly mounted and cannot rotate. A gear ring 48 is mounted on the foundation of the crane 45, into which the gears, 16 and 16', of the slewing machinery 15 and 15', of the individual cranes 12 and 12' mesh. The upper end of the vertical column axle 43 is covered by a plate 49 supporting a slip-ring device 32 and is fitted with a bearing flange 50, located at some distance away from the lower end of the axle, and a supporting flange 51 with a stub axle 52 at its lower end.
Stability of the vertical column axle 43 is achieved by fixing the supporting flange 51 and stub axle 52 firmly to the support-ing plate, while the bearing flange 50 is attached to the base plate 44. The primary supporting structure 55, mounted on the axle 43 by means of upper and lower roller bearings 53 and 54, carries a vertical supporting plate 56 to which the first ~rane 12 is attached. This supporting plate 56 is fastened by bolts (not illustrated here) to a vertical plate 14 on the back of the crane 12. The primary supporting structure 55 is pro-vided with upper and lower horizontal recesses, 57 and 58, in which the secondary supporting structure 61, which rotates around the vertical column axle 43, is mounted on upper and lower roller bearings 59 and 60. The secondary supporting structure 61 is provided with upper and lower horizontal recesses 62 and 63 respectively, into which the roller bearings 53 and 54 mentioned above, running around the vertical column axle ~3 ~0 are fitted. The secondary supporting structure 61 has a verti-cal plate 56 which carries the second crane 12' and which, like the first crane 12, is fastene~ by bolts to a plate 14' attache~
to the back of the second crane 12'. The construction is other-wise the same as sho~ in Figures 1, 3 and 4. The cranes 12 and 12', working both singly and together, move in the same way as those shown in the first version.
In order to offset the downward pull of the first and second cranes 12 and 12', each is provided, if their size should make it necessary, with one or more travelling wheels, 33 and 33', moving on a circular track 64 attached to the base plate 44.
The version shown in Figure 5 has the advantage that instead of the large slewing rim with two smaller roller bearings as used in the first, second and third versions illustrated in Figures 1, 3 and 4, four small roller bearings can be used which do away with the difficulty of obtaining an expensive slewing rim manufactured in small series only, and which allow roller bearings to be used which can be manufactured in large series and are ~ence cheaper and more standardized.
Figure 6 shows, in highly simplified form, the funda-mental principle of a variant of the supporting structures ofth~ cranes 12 and 12'. The structures, here designated 65 and 66, are provided with vertical supporting plates 67 and 67' which at their lower end have horizontal projections, 68 and 68'. 8y this arrangement, the vertical plates 14 and 14' on the back of the cranes 12 and 12' can be bolted to the support-ing plates 67 and 67' while the bottom of the cranes can be bolted to the projections 68 and 68', thus increasing the strength of the attachment of the cranes to their supporting structures 65 and 66. In certain smaller versions of this crane type, bolting the cranes to the projections only wou1d be sufficient.
~19;~6Zl Some of the advantages offered by twin slewing cranes of the type described herein may be summarized as follows:
By using a vertical bearing axle, an articulated axle or tubular axle stubs co~bined with the structures supporting each crane, and by attaching the crane to a base plate which can be rotated on a slewing rim in versions 1, 2 and 3 a single slewing rim and two mechanically identical cranes without individual slewing rim or gear rings can be used.
By using a simple vertical column axle, in version 4, a number of roller bearings and supporting structures to carry the individual cranes, even the single slewing rim mentioned above can be avoided. Here, too, mechanically identical cranes without individual slewing rims can be used.
By eliminating the platform used in conventional cranes the height of this type of twin crane can be decreased.
By eliminating the large size slewing rims and gear rings hitherto used in the construction of the base of single cranes, and by omitting in the platform, the construction is simplified at the same time as building costs and total weight are reduced.
By eliminating all large size slewing rims in the fourth version and instead using more conventional roller bearings, the difficulties associated with obtaining and purchasing expensive special bearings is avoided.
By the method of construction of this twin crane, and by using the slewing machineries of the individual cranes for operation of the cranes either singly or as a pair, the slewing machinery and provision for power supply hitherto used can be avoided, meaning that testing, inspection and maintenance can be more simply carried out.
_ g _ By the method of construction used, costs of transport and assembly on board ship can be reduced as compared with conventional cranes.
Details of design of the examples of the embodiment described herein may be modified within the limits of the claims. Thus, in versions 1, 2 and 3, a recess may be provided in the middle of the supporting structure instead of at its upper and lower ends, and a bearing may be mounted there in-stead. Again, the number of bearings could, e.g. be increased or that the roller bearings replaced by slide bearings, or the supporting structures and slewing structures may be provided with a number of recesses following the principle of the "piano hinge". Another possible modification would be to place the travelling wheels at a greater distance fram the common vertical axis of the crane, under each individual crane, for instance.
This application is a division of Canadian Patent Application Serial ~o. 287,443 filed September 26, 1977.
Claims (3)
1. A twin-type slewing crane, comprising:
an upright foundation with a ring gear secured thereon, the ring gear having a generally vertical axis;
a generally horizontal base plate mounted on said foundation:
two individual cranes, each having: a luffing jib with means including a hoisting rope running from a winch of that crane to a jib thereof for raising and lower-ing the jib, a supporting means for each crane, each mounting a respective crane for rotation about said central axis at the same distance from said central axis as one another, a rotating mechanism for each crane and projecting therefrom into meshing relationship with said ring gear, whereby operation of said rotating mechanism of at least one of said cranes propels at least that respective crane about said central axis, a central axle coaxially disposed on said central axis and extending upwards from said base plate, two axially intercalated sets of two axially spaced bearings, each bearing having an inner race mounted on said axle, one set having an outer race of each bearing thereof mounted on the supporting means of one of said cranes and the other set having an outer race of each bearing thereof mounted on the supporting means of the other of said cranes, and anti-tipping roller means between said sup-porting means of each of said cranes and said base plate.
an upright foundation with a ring gear secured thereon, the ring gear having a generally vertical axis;
a generally horizontal base plate mounted on said foundation:
two individual cranes, each having: a luffing jib with means including a hoisting rope running from a winch of that crane to a jib thereof for raising and lower-ing the jib, a supporting means for each crane, each mounting a respective crane for rotation about said central axis at the same distance from said central axis as one another, a rotating mechanism for each crane and projecting therefrom into meshing relationship with said ring gear, whereby operation of said rotating mechanism of at least one of said cranes propels at least that respective crane about said central axis, a central axle coaxially disposed on said central axis and extending upwards from said base plate, two axially intercalated sets of two axially spaced bearings, each bearing having an inner race mounted on said axle, one set having an outer race of each bearing thereof mounted on the supporting means of one of said cranes and the other set having an outer race of each bearing thereof mounted on the supporting means of the other of said cranes, and anti-tipping roller means between said sup-porting means of each of said cranes and said base plate.
2. The twin-type slewing crane of claim 1 wherein:
each supporting means includes a generally radially outwardly facing generally vertical plate having the respec-tive crane secured thereto.
each supporting means includes a generally radially outwardly facing generally vertical plate having the respec-tive crane secured thereto.
3. The twin-type slewing crane of claim 2 wherein:
the generally vertical plates each further includes a generally horizontal shelf upon which the respective crane is supported.
the generally vertical plates each further includes a generally horizontal shelf upon which the respective crane is supported.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA353,312A CA1103621A (en) | 1976-10-08 | 1980-06-03 | Twin type slewing crane |
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE7611188A SE401495B (en) | 1976-10-08 | 1976-10-08 | SWIVEL DOUBLE CRANE |
| SE7611188-9 | 1976-10-08 | ||
| CA287,443A CA1084452A (en) | 1976-10-08 | 1977-09-26 | Twin type slewing crane |
| CA353,312A CA1103621A (en) | 1976-10-08 | 1980-06-03 | Twin type slewing crane |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1103621A true CA1103621A (en) | 1981-06-23 |
Family
ID=27165296
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA353,312A Expired CA1103621A (en) | 1976-10-08 | 1980-06-03 | Twin type slewing crane |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1103621A (en) |
-
1980
- 1980-06-03 CA CA353,312A patent/CA1103621A/en not_active Expired
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