The invention relates to a boom that comprises a first boom part and a second boom part connected to each other by a connecting member. When the boom is lowered to its transport position, the boom parts are side by side.

The invention further relates to a personnel hoist and a method for using it. The field of the invention is described in more detail in the preambles of the independent claims of the patent application.

Higher and higher buildings are constructed all the time, which is why the personnel hoists of fire and rescue services need to be equipped with cage booms that extend ever higher. The current boom solutions extend to a height of nearly 100 m. However, it is difficult to increase the extension length of a boom, because the total height of a personnel hoist in its transport position needs to be rather low so as to allow the personnel hoist to fit under bridges and through tunnels of a normal road network. To make the height of the boom in its transport position as low as possible, a connecting member is arranged between the boom parts in the boom to allow the lowering of the upper boom part to the side of the lower boom part in the transport position. However, with booms of extremely high extensibility, problems have been detected in the stability and usability of the personnel hoist. These problems are caused, among other things, by the fact that the longitudinal axes of the boom parts are at a distance from each other and, in addition, the loads directed to the boom change during the use of the boom depending on the use direction of the boom. Thus, the present structures include drawbacks that limit the increase in the boom extension. In GB-1484263-A is disclosed a platform positioning machine and in US-5769251-A is disclosed a boom of a mobile crane.

It is an object of the present invention to provide a novel and improved boom, personnel hoist, and method for using it.

The boom of the invention is characterised by features of characterized portion of the first independent apparatus claim.

The personnel hoist of the invention is characterised by features of characterized portion of the second independent apparatus claim.

The method of the invention is characterised by features of characterized portion of independent method claim.

The idea is that between the boom parts, there is a connecting member that comprises a first connection part and a second connection part with a turning axis between them. The first connection part is fastened to the top end of the lower, first boom part, and the second connection part is fastened to the bottom end of the upper, second boom part. The connecting member permits the turning of the second boom part between transport and turning positions. In the transport position, the boom parts are side by side and their axes are on different vertical planes. When the second boom part is turned to its turning position, its axis is substantially on the same vertical plane with the first boom part.

One advantage is that the axes of the boom parts are on the same vertical plane in the use position, whereby no crosswise distance is formed between the axes or a torque arm caused thereby that causes sideward loads on the lower boom part. When stresses that are lower than before are directed to the first boom part, its structure can be made lighter. In addition, the present connecting member improves the stability of the boom.

The idea of an embodiment is that in the turning position the centre of gravity of the boom is kept continuously on one and the same side of an imaginary vertical axis that runs through the fastening point of the bottom end of the boom. Thanks to this application, loads do not move from one side of the boom to the other, and a load that is continuously in the same direction and, thus, also easier to take into account in the design of the boom construction, is directed to the boom. Therefore, the boom may be designed lighter, when the loads are better controlled. In addition, the boom is more stable in use, when the direction of the loads does not vary continuously during use.

The idea of an embodiment is that the second boom part is turned 180° or nearly 180° relative to the turning axis, when it is moved into the turning position.

The idea of an embodiment is that on the turning axis there is one or more turning members that connect the first and second connection parts turnably to each other. The turning member may be an elongated pivot pin, for instance, or some other corresponding member that permits turning.

The idea of an embodiment is that the turning axis has only one turning member that connects the first and second connection parts turnably to each other. The turning member may be an elongated pivot pin, for instance, or some other corresponding elongated member. One uniform turning member enables a simple and robust structure.

The idea of an embodiment is that the centre axis of the turning member has one or more channels. The channel may be a pipe, tube, cable, or a corresponding transfer member or path intended for transferring water, extinguishing medium, pressure fluid, compressed air, or electricity. When a transfer path of this type is in the turning centre, forces from the turning of the second boom part are not directed around its longitudinal axis, whereby no complex means allowing turning are not required in connection with the transfer path.

The idea of an embodiment is that one or more medium channels are led through the centre axis of the turning member.

The idea of an embodiment is that the turning member is a tubular piece with one or more water pipes arranged therein.

The idea of an embodiment is that the connecting member comprises one or more turning devices, the linear motion of which is transformed into a turning motion. The turning device is a pressure medium-operated cylinder, preferably a hydraulic cylinder. Cylinders are inexpensive and reliable turning devices. In addition, a cylinder may generate a high force in relation to its size.

The idea of an embodiment is that the connecting member comprises at least two turning devices and the size of the turning motion generated by both of them together moves the second boom part between the transport and turning positions. The first turning device and the second turning device are hydraulic cylinders which both provide a limited turning angle. The first turning device is connected between the first boom part and a turning piece fastened to the turning device and, correspondingly, the second turning device is connected between the second boom part and the turning piece. By means of the first turning device, the second boom part may be turned 90° relative to the turning piece and, correspondingly, by means of the second turning device, the turning piece can be turned 90° relative to the first boom part, whereby the second boom part also turns. Thanks to this embodiment, complex joint mechanisms that are difficult to manufacture, require maintenance and are prone to malfunction, are no longer needed. The present turning mechanism can also be designed to be very rigid and strong. Turning devices may be used in steps or simultaneously to provide the necessary turning motion.

The idea of an embodiment is that the second boom part is turned at a limited angle relative to its horizontal joint before it is moved in relation to the turning axis of the turning piece from the transport position to the turning position. When the second boom part is opened to some extent, there is more room for turning.

The idea of an embodiment is that the second boom part is loaded before it is turned from the transport position to the turning position. Before the second boom part is turned, one or more persons step into the man cage. Thus, the boom is under load during turning. It is then possible to step into the man cage from the carriage, which speeds up the driving of the boom to the operating site.

The idea of an embodiment is to use the boom without turning the second boom part into its turning position in situations where the operation takes place at a limited height. The telescopic first boom part is then not extended at all or at least not to its full length. When operating at smaller heights, the second boom part may be on the "back side" of the boom, that is, on the opposite side to the lifting cylinders. At smaller heights, the stability and loads usually do not cause problems. When operating at high altitudes, the second boom part is turned onto the same vertical plane with the first boom. This embodiment may be used for instance to facilitate entering the man cage, when operating at relatively low heights, or when the boom is used at sites below the operating carriage, downward from a bridge or slope, for instance.

The idea of an embodiment is that the connecting member comprises locking means with which the second connection part can be locked into the transport position and turning position, respectively. Locking improves the stability and safety of the boom.

The idea of an embodiment is that the connecting member has locking means, the operating status of which is monitored by means of one or more sensors. Sensor data is transmitted from the sensor to one or more control units of the personnel hoist to be taken into account in the control of the boom. The sensor means help avoiding dangerous situations and incorrect use of the boom. It is also possible to detect if the locking malfunctions.

The idea of an embodiment is that the connecting member comprises locking lugs and locking actuators for locking the second connection part into the transport position and turning position. The locking actuator may be a locking cylinder, the piston rod of which is pushed in a locking opening in the locking lug to achieve locking and pulled out of the locking opening to release the locking. This type of locking is simple, reliable, and firm. In addition, it is relatively easy to manufacture and service.

The idea of an embodiment is that the connecting member comprises at least one turning device that may be locked stationary so that the motion of the second connection part can be locked in the transport and turning positions. Separate locking means are then not absolutely necessary in the connection parts.

The idea of an embodiment is that on the turning axis there is one or more turning bearings, such as a ball race, which connect the first and second connection parts turnably to each other.

The idea of an embodiment is that the personnel hoist comprises a control cabin that is located on the front part of the movable carriage. The turning frame is, in turn, located on the back part of the movable carriage. In the transport position, the boom is then between the control cabin and turning frame. Owing to this embodiment, the layout of the carriage is easier to arrange suitable, and weight distribution can be made advantageous.

The idea of an embodiment is that the personnel hoist comprises a control unit containing a control strategy for controlling the boom. The control unit may for instance be arranged to make sure that, during use, the centre of gravity of the boom remains on one and the same side relative to the vertical axis running through the bottom end of the boom. This improves the safety of the personnel hoist.

The idea of an embodiment is that the personnel hoist comprises a control unit containing a control strategy for controlling the boom. The control unit may have an automatic mode for the operator to select when the boom is taken into use after a transfer run. Automatic control may drive the boom to a predefined starting position, and it may also open the boom parts in a predefined manner. An automatic start function may facilitate and speed up the work, improve the safety of the personnel hoist, and it may also help avoid incorrect operation of the boom and the equipment damage caused thereby.

Some embodiments of the invention will be described in more detail in the attached drawings, in which

• Figure 1a is a schematic representation of a prior-art personnel hoist in its upper position;
• Figure 1b is a schematic representation of a personnel hoist according to the invention in its upper position;
• Figure 2 is a schematic side representation of a personnel hoist according to the invention;
• Figure 3 is a schematic representation of a prior-art connecting member with which boom parts are attached to each other;
• Figure 4 is a schematic representation of a connecting member according to the invention for connecting boom parts turnably to each other;
• Figure 5 shows the connecting member of Figure 4 after the second boom part has been turned from the first position shown in Figure 4 to its second position;
• Figure 6 is a schematic representation of means connected to the connecting member, with which the second boom part may be turned 180° in relation the first boom part;
• Figure 7 is a schematic sectional view of a part of the connecting member and shows in particular a hollow pivot pin with at least one channel through it;
• Figures 8a to 8c are schematic representations of the steps of turning the second boom part as seen from the top of the first boom part; and
• Figure 9 is a schematic representation of a second connecting part.

In the figures, some embodiments of the invention are shown simplified for the sake of clarity. Similar parts are marked with the same reference numbers in the figures.

Figures 1a, 1b, and 2 show the basic construction of a personnel hoist 1 comprising a carriage 2 and a boom 3 arranged thereto. The carriage 2 may be a movable carriage, such as a vehicle or trailer. The carriage 2 may have a turning frame 4 to which the bottom end of the boom 3 is fastened by a first joint 5. At the top end of the boom 3, there may be a man cage 6 with space for lifting one or more persons. In addition, in connection with the man cage 6, there may be necessary tools, such as means for spraying fire extinguishing medium. The boom 3 may comprise a first boom part 3a and a second boom part 3b that are connected to each other with a second joint 7. The bottom of the first boom part 3a is fastened to the turning frame 4 by means of the first joint 5, whereby it may be lifted and lowered in relation to the joint 5 in the manner shown in the figures by arrow A. By turning the turning frame 4, the boom 3 may be moved sideways, which is shown by arrow B in the figures. The second boom part 3b may be lifted and lowered in relation to the second joint 7, as shown by arrow C. Further, the length of the first boom part 3a and second boom part 3b may be altered telescopically, whereby the boom may be extended for the use position shown in Figures 1 a and 1 b and shortened for the transport position shown in Figure 2. The movements of the telescopic parts are indicated in the figures by arrows Da and Db. The man cage 6 may also have an auxiliary boom 6a or a corresponding member with which the man cage 6 is connected to the top end of the second boom part 3b.

Figure 1 a shows a known personnel hoist 1 in which the second boom part 3b is connected to the top part of the first boom 3a by means of a fixed connecting member 8 shown in Figure 3. The second boom part 3b is all the time on a different vertical plane to the axis of the first boom part 3a. In Figure 1a, a dot-and-dash line shows the vertical axis P that runs through the bottom end of the boom 3. When the boom 3 is moved during use, the centre of gravity of the boom 3 changes depending on the position of the second boom 3b. Sometimes the centre of gravity is on the left side of the vertical axis P in the figure and sometimes on the right side. The loads directed to the boom 3 then vary from side to side, which causes instability in a long boom 3. In addition, a directionally variable load is directed to the boom 3, which causes strain on its structure. Further, as shown in Figure 3, the axis of the first boom part 3a and that of the second boom part 3b are at a cross-direction distance L from each other, that is, there is a torque arm between them. The mass of the second boom part 3b then causes a crosswise torsional load to the first boom part 3a. All in all, load management and stability are big challenges in this construction. If this structure is applied to the personnel hoist 1, the extensibility of the boom 3 can no longer be increased in a sensible manner.

Figure 1b shows a personnel hoist 1 according to the invention, in which the drawbacks of the prior art can be avoided, because the boom parts 3a, 3b are connected to each other with a turnable connecting member 8 of the type shown in Figures 4 and 5. During the use of the boom 3, the second boom part 3b can then be turned in the direction of arrow E shown in Figure 1b 180° or nearly 180° in relation to the first boom part 3a, whereby the axis of the second boom part 3b arrives at the same imaginary vertical plane T as that of the first boom part 3a. In addition, when operating at greater heights, the second boom part 3b is continuously on the "belly side" of the boom, that is, on the side of the lifting cylinders. Even though the second boom part 3b is moved during use in the direction of arrow C, the centre of gravity of the boom 3 remains all the time on the same side of the vertical axis P running through the foot of the boom. The loads then do not vary during the use of the boom, and the boom may be more stable than before when operating at great heights.

Movements of the second boom part 3b, when it has not yet been turned into its turning position, are marked by dashed lines V1 and V2 in Figure 1 b. It is, in fact, possible to utilize the second boom part 3b at heights smaller than a predefined height Y when operating on the "back side" of the boom. When operating at a relatively small height, moving the boom in this manner does not cause problems with stability, nor does it load the structures significantly. When it is necessary to operate at greater heights, the second boom part 3b is turned to its turning position.

Figure 1b also shows the driving of the boom 3 to its use position. First, the first boom part 3a can be lifted up, after which the second boom part 3b is turned to some extent in relation to the joint 7, that is, the second boom part 3b is opened U. After this, loads may be set on the boom 3, the second boom part 3b may be turned to its turning position, and the boom parts extended. Alternatively, if the operation takes place at smaller heights, loads can be set on the boom and it can be used without turning the second boom part 3b to its use position.

In Figure 2, the personnel hoist 1 is shown in the transport position, in which its height H may be 4 metres or less. The personnel hoist 1 can then be transported along normal road networks without its height H restricting its use in any way. The carriage 2 may be a truck, for instance. As seen in Figure 4, the turning frame 4 may reside at the back of the carriage 2, that is, at the opposite end to the control cabin 9. This is advantageous for weight distribution and the reach of the device, for instance. When the turning frame 4 is at the back of the carriage 2, the man cage 6 in its transport position is also at the back of the carriage 2. It is then easy to get into the man cage 6 from the back of the carriage. In addition, the man cage 6 may in the transport position be on the section over the back of the carriage, whereby the space required by the man cage 6 downward from the boom 3 does not set requirements to the carriage structures. The carriage 2 also comprises ground supports on which the carriage is supported before starting to use the boom. In connection with the personnel hoist 1, there may also be sensors for detecting that the carriage is properly supported. The control unit of the personnel hoist may be arranged to allow the use of the boom only after the support of the carriage has been detected.

Figures 4 and 5 show the structure and operation of the connecting member 8. In Figure 4, the connecting member 8 is in its unturned basic position, that is, in the position in which it is when the boom 3 is in the transport position shown in Figure 2. The connecting member 8 fastens the first boom part 3a and the second boom part 3b permanently to each other and they are not separated from each other at any time, excluding possible maintenance and repair. The connecting member 8 comprises a first connection part 10a and a second connection part 10b with a turning axis K between them. The first connection part 10a is fastened to the top end of the lower, first boom part 3a, and the second connection part 10b is fastened to the bottom end of the upper, second boom part 3b. The connecting member 8 permits the turning of the second boom part 3b between the transport and turning positions. In the transport position, the boom parts 3a, 3b are side by side and their axes are on different vertical planes. When the second boom part 3b is turned to its turning position in direction E, its axis is substantially on the same vertical plane T with the first boom part 3a, as shown in Figure 5.

On the turning axis K, there may be one or more turning members 11 with which the connection parts 10a, 10b are turnably connected to each other. The turning member 11 and connection parts 10a, 10b thus form a type of hinge, the turning axis K of which is parallel to the axis of the first boom part 3a. The turning member 11 may comprise a channel 12 on the turning axis K, and it is possible to lead through it one or more medium pipes or tubes, electric cables or any type of transfer path for transporting energy or a medium between the boom parts 3a, 3b. Figure 5 shows that on the turning axis K there may be two tubular turning members 11 a, 11 b that connect the connection lugs in the connection parts 10a, 10b to each other.

Figures 4 and 5 also show that the connecting member 8 is equipped with locking members with which the connection parts 10a, 10b can be rigidly locked into the transport position and turning position, respectively. The locking members may comprise first locking lugs 13a that are compatible in the transport position and second locking logs 13b that are compatible in the turning position and the locking lugs intermesh so that the openings 14 in them are aligned. A locking pin 15 can then be pushed through the openings 14 by means of a locking cylinder 16 or a corresponding locking mechanism. The locking pin 15 and cylinder 16 are shown in Figures 6, 7, and 9. As can be seen in the figures, the piston rod of the locking cylinder 16 may serve as the locking pin 15.

A possible turning mechanism is shown in Figure 6. The connecting member 8 may comprise two turning devices 17a, 17b, and the size of the turning motion provided with both of them together moves the second boom part 3b between the transport and turning positions. The turning devices may be hydraulic cylinders which both provide a limited turning angle. The first turning device 17a is connected between the first boom part 3a and a turning piece 18 fastened to the turning member 11. Similarly, the second turning device 17b is connected between the second boom part 3b and the turning piece 18. By means of the first turning device 17a, the second boom part 3b may be turned 90° and, correspondingly, by means of the second turning device 17b, it can be turned 90° relative to the first boom part 3a. Figures 8a to 8c show the operation of the turning mechanism in more detail. Figure 6 also shows that the connecting member 8 may be equipped with mechanical limiters 19 with which the turning motion can be limited. Then, the motion of the turning devices 17a, 17b does not need to be precisely controlled. The limiter 19 may be a pin with adjustable length. Figure 6 also shows locking means that may include locking lugs 13a, 13b, locking openings, and locking cylinders 16.

Figure 7 shows a detail of the structure of the connecting member 8. The piston rod 15 of the locking cylinder 16 may extend through the locking lugs 13a and lock the connection parts stationary. In connection with the locking device, there may be one or more sensors 20 for monitoring the operation of the lock. Locking information may be transmitted to a control unit 21 that prevents the boom being lifted higher before locking has been accomplished in the turning position. In addition, through monitoring it is possible to obtain information on the condition and service requirements of the locking device.

Figure 7 further shows a connection member 11 that is an elongated tubular piece, a kind of hollow hinge pin that connects the connection parts 10a, 10b turnably to each other. One or more transfer paths 22, such as a pressure medium pipe, pressure medium tube, electric cable, or the like, may be arranged through the channel on the turning axis of the connection member 11.

Figures 8a to 8c shows step by step the turning of the second boom part 3b from its basic position to the turning position. In Figures 8b and 8c, the structure is shown in a highly simplified manner for the sake of clarity. In Figure 8b, the first turning device 17a has finished its work cycle and pushed the turning piece 18 90° around the turning axis K, whereby the second boom part 3b has turned 90°. In Figure 8c, the second turning device 17b has also finished its work cycle, whereby only the second boom part 3b has turned yet another 90° while the turning piece 18 remains stationary held by the first turning device 17a. The linear movement of the two cylinders 17a, 17b is through this structure transformed into a turning movement. The turning devices 17a, 17b may be arranged to operate in the manner shown in the figures step by step or, alternatively, they may operate at simultaneously.

Figure 9 shows the second connection part 10b in perspective. The features described above are marked by reference numbers in the figure. In addition to these, the figure also shows lugs 24 through which the axle of the turning joint 7 is arranged.

Differing from the embodiment shown in Figures 6, and 8a to 8c, it is also possible to use one single turning device or more than two, for instance three or four, turning devices. Further, it is possible that the turning device is not a cylinder but some other actuator, such as a hydraulic motor. Further, instead of hydraulics, it is possible to use some other pressure medium, such as compressed air. It is also possible to equip the connecting member with one or more electric turning devices.

In some cases, the features described in this application may be used as such, regardless of other features. On the other hand, the features described in this application may also be combined to provide various combinations as necessary.

It should yet be noted that the above features may also be used in booms that differ from those presented above by not comprising a man cage. This may then be a boom intended for rescue operations that comprises in a similar manner at least first and second boom parts and a connecting member of the described type between the boom parts, whereby the upper boom part may be turned into its turning position in which it is substantially on the same vertical plane with the lower boom part. This type of rescue boom may comprise one or more rescue actuators, the operation of which can be remote-controlled. For remote control, the rescue boom may be equipped with one or more cameras, heat sensors or the like. A rescue actuator may comprise means for supplying extinguishing medium. Thus, the rescue actuator may be a water sprayer or an extinguishing foam nozzle. Other possible devices required in rescue and fire fighting operations are also possible. Further, it is possible that the top part of the boom has a snap lock member to which any tool, such as a sprayer or man cage, used in rescue operations can be fastened.

The drawings and the related description are only intended to illustrate the idea of the invention. The invention may vary in its details within the scope of the claims.