KYLÄNPÄÄ, Harri (Luhtaniityntie 15 A 8, Akaa, FIN-37800, FI)
| CLAIMS 1. A ladder of a personnel hoist, the ladder being attached to a boom (1 ) of the personnel hoist (1 ) and comprising: an elongated first ladder frame (11a) and an elongated second ladder frame (11 b) arranged at a distance from each other; a plurality of steps (13) arranged between the ladder frames (11a, 11b); and an elongated first rail (9a) connected by means of a turning mechanism to the first ladder frame (11a), and an elongated second rail (9b) connected by means of a turning mechanism to the second ladder frame (11 b) in such a way that the rails (9) can be turned down to a transport position and up to an operating position relative to the ladder frames (11 ); whereby the rails (9) are arranged to move, during the turning, in the longitudinal direction (L) of the ladder (8); characterized in that the turning mechanism comprises at least one turning actuator (16) for moving the rails (9); and the first rail (9a) and the second rail (9b) are connected to each other by means of at least one connecting member arranged to transmit turning motion between the rails (9a, 9b). 2. A ladder according to claim ^ characterized in that the rail (9) is connected to the ladder frame (11) by means of a plurality of intermediate bars (12); the first end of each intermediate bar (12) is connected to the ladder frame (11) by means of a first joint (14), the second end of each intermediate bar (12) being connected to the rail (9) by means of a second joint (15); and the turning axes of the first joint (14) and the second joint (15) are transverse to the longitudinal axis of the ladder (8). 3. A ladder according to claim 1 or 2, characterized in that the rail (9) is arranged to become positioned against the ladder frame (11 ) in the transport position. 4. A ladder according to any one of the preceding claims, characterized in that the ladder (8) comprises a first ladder part and a second ladder part which are movable in the longitudinal direction relative to each other, whereby the length of the ladder is decreasable and increasable; and both the first ladder part and the second ladder part comprise a turning mechanism of their own for turning the rails to the transport position and to the operating position. 5. A ladder according to any one of the preceding claims, c h a r a c t e r i z e d in that the first rail (9a) and the second rail (9b) are connected to each other with at least one transverse connecting bar (19) arranged to synchronize the turning motion between the rails (9a, 9b). 6. A personnel hoist, comprising: a base (2); a turning frame (4) arranged turnably on the base (2); a boom (3), the lower part of which is connected to the turning frame (4) by means of a horizontal joint (5); at least one man cage (6) arranged in the upper part of the boom (3); at least one ladder (8) attached to the boom (3) and comprising: an elongated first ladder frame (11a) and an elongated second ladder frame (11 b); a plurality of steps (13) between the ladder frames (11 ); and, further, a first rail (9a) and a second rail (9b), which rails (9) are arranged to be turned to a transport position and to an operating position by means of a turning mechanism; whereby the turning mechanism comprises turning axes transverse to the longitudinal direction (L) of the ladder (8); and whereby the rails (9) are arranged, during turning, to move in the longitudinal direction (L) of the ladder (8) along a curved path (E); c h a r a c t e r i z e d in that the turning mechanism comprises at least one turning actuator (16) for moving the rails (9); and the first rail (9a) and the second rail (9b) are connected to each other by means of at least one connecting member (19) arranged to transmit turning motion between the rails (9a, 9b). 7. A method for using a ladder of a personnel hoist, the method comprising: keeping rails (9) of the ladder (8) in the lower position during the transport of the personnel hoist (1 ); allowing the rails (9) to be raised up to a distance from a ladder frame (11 ) when a boom (3) of the personnel hoist (1 ) is in an operating position (A); and raising the rails (9) by turning them from the transport position to the operating position by means of their turning mechanism; whereby the rails (9) are turned relative to turning axes transverse to the longitudinal direction (L) of the ladder (8), which causes the rails (9) to move in the longitudinal direction (L) of the ladder (8); c h a r a c t e r i z e d by turning the rails (9) by means of at least one turning actuator (16); and transmitting the turning motion between the first rail (9a) and the second rail (9b), whereby the rails (9a, 9b) on opposite sides of the ladder (8) are arranged to move simultaneously. |
BACKGROUND OF THE INVENTION
[0001] The invention relates to a ladder of a personnel hoist, the ladder being attached to a boom of the personnel hoist. The ladder comprises an elongated first ladder frame and an elongated second ladder frame arranged at a distance from each other and having a plurality of steps. An elongated first rail and an elongated second rail are connected by means of a turning mechanism to the ladder frames in such a way that the rails can be turned down to a transport position and up to an operating position relative to the ladder frames.
[0002] Further, the invention relates to a personnel hoist and to a method for using a ladder of a personnel hoist.
[0003] The field of the invention is described in more detail in the preambles of the independent claims of the application.
[0004] Personnel hoists are used in the fire and rescue services, in particular, but also in building contract work and in various maintenance and repair tasks. A personnel hoist comprises a boom next to which there is a ladder ensuring access into a man cage at the end of the boom as well as out of it if, for some reason, the boom cannot be steered down. Further, the ladder may also be utilized in other ways when operating with the boom. According to the safety regulations, the ladder must be provided with rails. The rails cause problems with regard to space utilization because when the boom has been steered to the transport position, the rails require a lot of space. One known solution is to arrange the rails to be turnable in the cross-direction of the ladder, in which case the ladder can be turned to the upper position in an operating situation and to the lower position for transport. Unfortunately, the ladder which has been turned down as well as its support bars prevent the access along the ladder when the turning mechanism has been stuck to the lower position due to a failure or freezing or for another reason.
BRIEF DESCRIPTION OF THE INVENTION
[0005] An object of this invention is to provide a novel and improved ladder of a personnel hoist, a personnel hoist, and a method for using a ladder of a personnel hoist.
[0006] The ladder of a personnel hoist according to the invention is characterized in that the turning mechanism comprises at least one turning actuator for moving the rails; and that the first rail and the second rail are connected to each other by means of at least one connecting member arranged to transmit turning motion between the rails.
[0007] The personnel hoist according to the invention is characterized in that the turning mechanism comprises at least one turning actuator for moving the rails; and that the first rail and the second rail are connected to each other by means of at least one connecting member arranged to transmit turning motion between the rails.
[0008] The method according to the invention is characterized by turning the rails by means of at least one turning actuator; and transmitting the turning motion between the first rail and the second rail, whereby the rails on opposite sides of the ladder are arranged to move simultaneously.
[0009] An idea of the invention is that the ladder comprises rails which can be raised to the operating position and lowered to the transport position. The rails are moved between the operating position and the transport position by turning them relative to pivoting pins that belong to the turning mechanism and are transverse to the ladder. Thus, the rails move, during the raising and lowering, along a curved path in the longitudinal direction of the ladder without any transverse motion. The rails are turned by means of one or more turning actuators whose turning motion is transmitted and synchronized by means of one or more connecting members between the rails on different sides of the ladder.
[0010] An advantage of the invention is that the rails are not, in any situation, on the route of the ladder, owing to which the ladder can be used even if the turning mechanism of the ladder failed or the rails stuck to its lower position. The safety is thus improved by the invention. Further, moving of the rails is synchronized by means of one or more connecting members. Further, when the turning mechanism comprises one or more turning actuators for moving the rails, the rails can be turned up and down by machine power, which facilitates and accelerates the use. Furthermore, the rails may, if required, be moved by remote-control and it may also be automated.
[0011] The idea of an embodiment is that the turning motion of the rails on different sides of the ladder is synchronized by means of one or more connecting bars. The connecting bar is positioned crosswise relative to the longitudinal axis of the ladder. [0012] The idea of an embodiment is that the rail is connected to the ladder frame by means of a plurality of intermediate bars. The lower end of the intermediate bar is connected to the ladder frame by means of a first joint, and the upper end of the intermediate bar is connected to the rail by means of a second joint. The first and second joints comprise turning axes the direction of which is transverse to the longitudinal axis of the ladder. Thus, when the rails are raised and lowered, both the intermediate bars and the rails move in the longitudinal direction of the ladder.
[0013] The idea of an embodiment is that the rails on different sides of the ladder are moved by means of one single turning actuator because the turning motion can be transmitted to the other rail by means of a connecting bar. In this case, too, the rails can be moved simultaneously. There may be fewer turning actuators than before, which simplifies the structure.
[0014] The idea of an embodiment is that the rails are arranged to become positioned against the upper surface of the ladder frame in the transport position.
[0015] The idea of an embodiment is that the turning mechanism comprises at least one sensor, measuring device or the like for identifying the position of the rails. The identification information may be transmitted to the control unit of the personnel hoist and it may be indicated to the operator of the personnel hoist.
[0016] The idea of an embodiment is that the ladder comprises a first ladder part and a second ladder part which are movable slidingly relative to each other in the longitudinal direction. Thus, the length of the ladder can be decreased or increased. The first ladder part and the second ladder part comprise separate turning mechanisms for turning the rails to the transport position and to the operating position.
[0017] The idea of an embodiment is that the boom of the personnel hoist comprises a first boom part and a second boom part which are arranged to be positioned one upon the other in the transport position. The outer boom is thus folded against the inner boom and it is below the inner boom, closer to the base. A first ladder is attached next to the first boom part, and a second ladder is attached next to the second boom part. The joint between the boom parts and the joint between the ladders have parallel turning centres. The first ladder and the second ladder become positioned one upon the other when the boom is steered to the transport position. The ladder attached to the outer boom part becomes positioned below the ladder attached to the inner boom part. Further, at least the rails of the ladder of the outer boom part are turned to their lower position before the boom is steered to the transport position. Thus, there remains a space below the ladders, for instance for positioning a cabin, a boot and auxiliary devices.
BRIEF DESCRIPTION OF THE FIGURES
[0018] Some embodiments of the invention will be explained in greater detail in the attached drawings, in which
Figure 1 shows schematically a side view of a personnel hoist;
Figure 2 shows schematically a side view of the boom of a personnel hoist in the operating position and in the transport position;
Figure 3 shows, schematically and obliquely from behind, the boom of a personnel hoist and a ladder attached next to it;
Figure 4 shows an arrangement according to the prior art for turning the rails belonging to the ladder up and down in the cross-direction of the ladder;
Figure 5a shows, schematically and in the longitudinal direction of the boom, the ladder attached to the boom in a situation where the rails are in the upper position;
Figure 5b shows, schematically and in the longitudinal direction, only the ladder after the rails have been lowered;
Figure 6 shows schematically a side view of the ladder according to the invention in a situation where the rail has been turned up;
Figure 7 shows schematically a side view of the ladder according to Figure 6 in a situation where the rail has been turned down;
Figure 8 shows schematically a side view of an arrangement for connecting the rails on opposite sides of the ladder in such a way that they always turn simultaneously;
Figure 9 shows schematically a top view of the positioning of a mechanical connecting bar belonging to the arrangement according to Figure 8 in the cross-direction of the ladder; and
Figure 10 shows a schematic perspective view of an alternative turning mechanism of the rails. [0019] For the sake of clarity, some embodiments of the invention are shown simplified in the figures. Similar parts are denoted with the same reference numerals.
DETAILED DESCRIPTION OF SOME EMBODIMENTS OF THE INVENTION
[0020] Figure 1 shows a personnel hoist 1 comprising a base 2 provided with a boom 3. The base 2 may be a movable carrier, such as a vehicle or a trailer. The base 2 may have a turning frame 4 to which the lower end of the boom 3 is attached by means of a first joint 5. The upper end of the boom 3 may have a man cage 6 with a space for hoisting one or more persons. In connection with the man cage 6, there may also be required work devices, such as means for spraying fire-extinguishing medium. The boom 3 may comprise only one boom part or it may comprise two or more boom parts connected pivotably to each other. The boom shown in Figure 1 comprises a first boom part 3a and a second boom part 3b, having a second joint 7 between them. The lower part of the first boom part 3a is attached to the turning frame 4 by means of the first joint 5, whereby it can be raised and lowered relative to the joint 5. Turning the turning frame 4 enables the boom 3 to be moved in the sideward direction. The second boom part 3b can be raised and lowered relative to the second joint 7. The length of the first boom part 3a and the second boom part 3b may be changed telescopically, whereby the boom 3 may be shortened to the transport position on the base, as shown in Figure 1. Correspondingly, the boom may be lengthened to a desired length in an operating situation. For the sake of clarity, Figure 1 does not show a ladder attached to the boom parts 3a, 3b at all.
[0021] Figure 2 shows a boom 3 by a continuous line in an operating situation A and by a broken line in a transport position B. The second boom part 3b may be arranged to be steered to below the first boom part 3a in the transport position B. In Figure 2, ladders 8a and 8b attached to the boom parts 3a, 3b are shown greatly simplified. Typically, the ladders 8a, 8b are arranged next to the boom parts 3a, 3b, whereby they also become positioned one upon the other in the transport position. The ladder 8a of the first boom part may comprise rails 9 that are fixedly in the upper position but it is also feasible that the rails are of a lowerable type. The rails 9 of the ladder 8b of the second boom part are typically of a lowerable type. If fixed rails were used in the ladder instead of lowerable ones, the rails 9 would point towards the base 2 in the transport position B, whereby they would restrict the positioning of the components on the base 2.
[0022] Figure 3 further shows the greatly simplified boom 3 of a personnel hoist as well as ladders 8a, 8b arranged next to its boom parts 3a, 3b, along which there is access to the man cage 6. The ladders 8a, 8b are connected to each other with a joint and further to the boom parts 3a, 3b with suitable connecting members 10.
[0023] Figure 4 shows an arrangement according to the prior art for raising and lowering the rails 9a, 9b. As seen, the rails 9 are connected to the ladder frames 11a, 11 b by means of intermediate bars 12. At the lower end of the intermediate bars 12, there is a joint 12a allowing the intermediate bar 12 and the rail 9 to be turned to their upper position and lower position in the cross-direction P of the ladder. In Figure 4, the left rail 9a has been turned down and the right rail 9b is still up. As seen from Figure 4, the intermediate bars 12 and the rails 9 prevent access along the ladder 8 in the lower position.
[0024] Figure 5a shows a solution according to the invention, where the intermediate bars 12 and the rails 9 are arranged to turn in the longitudinal direction of the ladder 8. When a rail 9 is turned from its upper position shown in Figure 5a to its lower position shown in Figure 5b, the rails 9 or the intermediate bars 12 do not move to the route of the ladder 8 but move only in the longitudinal direction of the ladder 8.
[0025] Figures 6 and 7 show, seen from one side, the principle of moving the rail 9. The ladder 8 comprises ladder frames 11 and steps 13 between them. The lower ends of the intermediate bars 12 are connected to the ladder frame 11 by means of a first turning joint 14 and, further, their upper ends are connected to the rail 9 by means of a second turning joint 15. The turning axes of the turning joints 14, 15 are transverse to the longitudinal axis of the ladder, which means that the intermediate bars 12 may turn only in the longitudinal direction L of the ladder 8. The turning mechanism comprises a turning actuator 16, which may be, for example, a pressure medium cylinder, preferably a hydraulic cylinder. The turning actuator 16 is connected to the ladder frame 11 by means of a joint 17a and to the rail 9 by means of a joint 17b. The linear motion of the turning actuator 16 in direction C causes the intermediate bars to turn in direction D and the rail 9 to turn along a curved path E, whereby the rail 9 moves simultaneously in the longitudinal direction L and, of course, in the height direction H of the ladder 8. The rails 9 on opposite sides of the ladder 8 may be used by turning mechanisms separate from each other, or alternatively, the rails 9 may be connected to be used by one common turning mechanism, as will be later seen from Figures 8 to 10.
[0026] It is also seen from Figure 7 that the rail 9 can be turned to be against the ladder frame 11 in the lower position, whereby it is in the lowest possible position.
[0027] Figure 8 shows a lever mechanism 18 which may be connected to a transverse connecting bar 19 transmitting the motion of the turning actuator 16 on a first side of the ladder to a second side of the ladder. Thus, one turning actuator 16 may be arranged to move the rails 9 on both sides of the ladder. Further, it is feasible that both sides of the ladder have turning actuators 16 of their own but then, too, the motions of the rails 9 can be synchronized by means of the connecting bar 19 and the lever mechanism 18 or the like connected to the connecting bar. The lever mechanism 18 shown in the figure comprises a crank 20 attached to the connecting bar 19 and connected to the rail 9 by means of a turning bar 21. The length of the turning bar 21 may be adjustable in such a way the heights of the rails 9 on different sides of the ladder 8 can be made equal in the upper position.
[0028] Figure 9 further shows a top view of a transverse connecting bar 19a of the ladder. A connecting bar 19b may also be arranged, if required, inside the step 13 having a tubular cross-section profile. For the sake of clarity, Figure 9 does not show any rails.
[0029] Figure 10 shows an alternative arrangement with which rails 9a, 9b can be connected to each other on opposite sides of the ladder 8. At least one intermediate bar 12a, 12b on each side opposite one another may be rigidly attached by the lower end to the connecting bar 19, which can be turned by means of a rotation motor or the like turning actuator 16. In this case, the intermediate bars 12a, 12b turn simultaneously in direction D. The intermediate bars 12 are connected pivotably to the rails 9a, 9b by their upper ends. The connecting bar 19 may be connected by means of a pivot directly to ladder frames 11a, 11 b.
[0030] In connection with the turning actuator, there may be one or more sensors with which the position of the turning actuator can be monitored. In such a case, the control system receives information on the position of the rails. Alternatively, the position of the rail, the position of the intermediate bars or the position of the connecting bar may be monitored directly. The monitoring information may be utilized in controlling the operation of the personnel hoist. The position of the rails may be indicated to the operator by means of signal lights, for example. The control system may also give alarms, for instance when the boom is being steered into the transport position while the rails are still in their upper position. The control system may naturally be arranged to automatically attend to the raising and lowering of the rails.
[0031] In some cases, features described in this application may be used as such, irrespective of other features. On the other hand, features described in this application may, if required, be combined to form various combinations.
[0032] The drawings and the attached specification are only intended to illustrate the idea of the invention. Details of the invention may vary within the scope of the claims.