Hook block and crane

Abstract

A hook block (1) for a crane, comprising at least one casing (2) covering at least partially one rope pulley, a load hook (3) connected to the casing (2) for lifting load, the hook block (1) is movable in at least one horizontal direction. The hook block (1) further comprises visually observable or readable means (5), wherein the visually or readable means (5) indicates a movable horizontal direction.

Description

[0001]HOOK^BLOCK^AND^CRANE TECHNICAL FIELD The present invention relates to a hook block, and more particularly to a hook block of a crane. BACKGROUND Storages, factories or workshops typically accommodate a crane, such as an overhead bridge crane, for facilitating lifting and moving heavy objects. A rope hoist may move along a main girder in x-direction and the main girder may move along two end girders in y-direction, perpendicular to the x-direction. This allows the rope hoist to move freely within the area defined by the end girders. A crane operator may control the movement of a hook block connected to the rope hoist via a controller. Typically, the controller has an emergency stop button, up and down buttons for respectively lifting and lowering the hook block which are vertical movements, and four direction buttons for four air directions which are horizontal movements. The four horizontal air directions are typically labeled on the bottom surface of the main girder to indicate which button corre- sponds to which direction. Whenever the crane operator needs to check the correct direction, it can be verified by checking the direction markings on the main girder. In some cranes, the hook block can only be moved in two horizontal directions in which case only two markings are necessary. However, due to storage shelves or other obstacles, the crane operator may not be able to see the direction markings. In some cases, the main girder is so high, the direction markings are too blurry to distinct them from each other. Addi- tionally, crane operators are required to wear a safety helmet with a peak, which can further obstruct the crane operator’s sight. Due to above disadvantages, the crane operator often has difficulties to determine the right button for the wanted direction-to-be-moved and must find out the correct direction by trying which direction the button pressed will guide the hook block. This takes additional time and may damage the load or surround- ings if the space is limited, and the direction button pressed resulted in an unex- pected direction. Especially when moving large and heavy items, it may even cause a risk of accidents for other workers next to the load or damaging the surrounding structures. BRIEF DESCRIPTION An object of the present invention is to solve the above-mentioned drawbacks and to provide a new type of hook block. This and other objects are achieved with the hook block according to the independent claim. Preferred embodiments are disclosed in dependent claims. The hook block is based on the idea of having visually observable or readable means arranged on a casing of the hook block for detecting the load hook position, which indicates the position of the hook block in relation to the crane or building. Some of the advantages obtained from this invention are better safety and more ergonomic working position for the user. The implementation is easy, fast to detect and cost-effective. BRIEF DESCRIPTION OF THE DRAWINGS In the following the invention will be described in greater detail by means of preferred embodiments with reference to the attached drawings, in which Figure 1 illustrates a top perspective view of a bridge crane; Figure 2 illustrates a perspective view of a hook block according to an embodiment; Figure 3 illustrates a top view of the hook block of Figure 2; Figure 4 illustrates a side view of the hook block of Figure 2: Figure 5 illustrates another side view of the hook of Figure 2; Figure 6 illustrates another side view of the hook of Figure 2; Figure 7 illustrates another side view of the hook of Figure 2; Figure 8 illustrates markings according to ANSI standard; Figure 9 illustrates markings according to FIN / SEN standard; Figure 10 illustrates an embodiment of markings in a simplified man- ner, Figure 11 illustrates another embodiment of markings in a simplified manner. DETAILED DESCRIPTION The present invention pertains to a hook block 1 for a crane, and spe- cially for an overhead bridge crane, a wall jib crane or a gantry crane. Figure 1 il- lustrates an example of a bridge crane. The hook block 1 can be part of a hoisting mechanism comprising a trolley 11 and a rope hoist 10 comprising a rope drum 12 for a hoisting rope 15 to be winded thereon and the hook block 1 is connected to the rope hoist 10 via the hoisting rope 15. The rope hoist 10 can be movable along a main girder 13 via the trolley 11. The main girder 13 can be movable on rails 14, so the main girder 13 is usually supported by said rails 14 at its ends. The rope hoist 10 may comprise a motor and a gearing for operating the rope drum 12 and the hook block 1. The rope drum 12 may have a single-layer winding or a multi- layer winding for the hoisting rope 15. The controller (not shown) can be a wireless radio, or it can be attached to the crane, for example suspended by a fixed cable. The cable or similar attach- ment may allow the controller to rotate, allowing the directions of the push buttons to be freely positioned in relation to the visually observable or readable means of the hook block 1. Figure 2 illustrates a perspective and simplified view of a hook block 1 according to an embodiment. The hook block 1 comprises a casing 2 cover- ing at least one rope pulley (not shown). The rope pulley is a rotatable grooved wheel for guiding and holding the hoisting rope allowing the hoisting rope to move up and down and minimizing the friction and wear on the hoisting rope. There may be more than one rope pulley in the hook block 1, such as two, three or four rope pulleys. The casing 2 may be a steel, aluminium or polymer enclosure housing one or more rope pulleys. The casing 2 may enclose the rope pulley completely or partially. The rope pulley can rotate, and the hoisting rope 15 can move freely in- side the casing 2 without contacting inner surface of the casing 2. The casing 2 also prevents the users accidentally touching the rope pulleys for safety reasons, and additionally minimalizing the dust accumulating to the rope pulleys. The rope pul- ley can rotate around a centre axis, and the casing 2 can be connected to the centre axis using a nut fixed to an end of the centre axis, such as an acorn nut for instance. The casing 2 may comprise two counterparts on both sides of the rope pulley ar- ranged to axially cover the entire rope pulley. The counterparts may be mutually identical. The casing 2 may comprise at least a partial flange radially covering at least a part of the edge of the rope pulley in the radial direction which further pre- vents the user from accidently touching the rope pulley. A load hook 3 is connected to the casing 2 for lifting load. The load hook 3 can be fastened to the casing 2 using a hook nut and a trunnion pin, for instance. The trunnion pin allows the load hook to rotate around a horizontal axis of the trunnion pin. The casing 2 may further comprise or is connected to an axial bearing with a bearing plate for allowing the load hook to rotate around a vertical axis. This allows facilitating of the free turning or rotating load hook. When load is lifted, it is often necessary to turn the load to position in a new location or to avoid hitting obstructions. The hook block 1 allows the load to be freely rotated without chang- ing the orientation of the hoisting rope. The load hook 3 may comprise a safety latch 4 for preventing the load from slipping off the load hook 3. If the hook block 1 has more than one rope pulley, the casing 2 may be arranged to cover all the rope pulleys, or there may be more than one casing, for example two, which are connected to each other via a connector. The connector in this context may refer to any object, separated from or integrated to the casing 2, rigidly connecting the casings together. The connector may be additionally ar- ranged to couple the load hook 3 to the casing 2. The hook block 1 is movable in at least one horizontal direction when it is suspended from the rope hoist. The hook block 1 further comprises visually ob- servable or readable means 5, wherein the visually or readable means 5 indicates or illustrates a movable horizontal direction of the hook block 1. Figure 3 illustrates a simplified top view of the hook block 1 according to Figure 2 where the visually observable or readable means 5 are detached from the hook block 1 but indicates the horizontal air directions. Figures 4-7 illustrates four side views of the hook block 1 according to Figure 2. The casing 2 may com- prise four peripheral surfaces 6, 7, 8, 9 on its side, wherein a first peripheral surface 6 and a third peripheral surface 8 are towards opposite directions, and a second peripheral surface 7 and a fourth peripheral surface 9 are towards opposite direc- tions, perpendicular to the direction of the first peripheral surface 6 and the third peripheral surface 8. In some embodiments, the flange of the casing 2 may be one of the peripheral surfaces 6, 7, 8, 9. The visually observable or readable means 5 may be arranged on each of the four peripheral surfaces 6, 7, 8, 9, wherein the four visually observable or readable means 5 indicate four movable horizontal air directions. Said peripheral surfaces 6, 7, 8, 9 may not be perpendicular to each other as the casing 2 may be other than the simplified cube shaped. For example, some casings may be a cylinder or barrel shaped. The term “peripheral surface” in this context may refer to the most outer surface of the hook block 1 facing away from the rope pulley or rope pulleys. In practice, the four movable horizontal air directions are relative to the movement of the crane, wherein the first and third movable air direction are in accordance with the movement of the rope hoist along the main girder, and the second and fourth movable air direction are in accordance with the movement of the main girder along the end girders. However, for instance in the wall jib crane, the main girder is secured to a wall via a support column from one end of the main girder (boom) only and rotatable around said support column. In these cases, the second and fourth movable air direction may be in accordance with the rotation direction around the support column. In the embodiment with more than one casing 2, the visually observable or readable means 5 may be arranged on the most peripheral surfaces 6, 7, 8, 9 of the casings and / or on surfaces of the connector in such a way that each of the four horizontal air directions are indicated on each surface facing towards said air di- rection. Each of the four movable air direction may be indicated by different marking. In the embodiment illustrated in the Figures 2-7, the markings are indi- cated using ANSI (American National Standards Institute) standard. Figure 8 illustrates the visually observable or readable means 5 indicat- ing exemplary markings according to ANSI standard. In ANSI standard, letter N (North) indicates a direction opposite to letter S (South). Letter E (East) indicates a direction opposite to W (West). The building with the crane may not literally align with the cardinal directions when they are built. Typically, one longitudinal direc- tion is marked as N regardless of whether it points to north or not. Figure 9 illustrates the visually observable or readable means 5 indicat- ing exemplary markings according SFS (Finnish Standards Association) standard. Instead of letters, SFS standard uses shapes, such as a rectangle, circle, triangle and square. The square and the triangle indicate opposite directions, and the circle and the rectangle indicate opposite directions. However, they may be implemented to indicate any direction, such as in SIS (Swedish Institute for Standards) standard where the rectangle and circle are mirrored compared to SFS standard. Using other standards or markings may also be implemented, such as DIN (Deutsches Institut für Normung) standard, which uses arrows pointing up, down, left and right. The visually observable or readable means 5 may also indicate different colours distinguishable from each other, or words or symbols meaning different air directions. In an embodiment, markings and symbols meaning different air direc- tions and different colours may be combined in such a way that for a specific direc- tion, that specific direction is marked with a specific colour. Different colours help the user to accurately and quickly differentiate the visually observable or readable means 5 for different air directions. The visually observable or readable means 5 may be colourful with optical contrast relative to the hook block 1, yet without in- creasing much weight to it. For example, if the hook block 1 is black, letter N can be coloured purple, letter E coloured orange, letter S coloured light blue, and letter W coloured green. Other colours may also be used and not restricted to the ones men- tioned in examples. This coloured marking can be easier for users, which has a poor sense of direction, and has challenges to perceive air directions. Respective mark- ings can be located under the crane structures, e.g. main girder 13, which can be detected by the user when looking up. Additionally, on the pillars or walls (not shown in Figures) supporting the rails 14 can be marked with mentioned direc- tions with specific colours, for example on northern wall letter N in purple, on east- ern wall letter E in orange, on southern wall letter S in light blue and on western wall letter W in green at every ten meters or on every second pillar. Alternatively, northern wall (N) can be painted in purple, eastern wall (E) can be painted in or- ange, southern wall (S) can be painted in light blue or the western wall (W) can be painted in green, or in combination thereof, without letters or symbols. Detecting the wanted driving direction, the user can be further assisted with the colour coded markings or their backgrounds on the hook block 1. Respec- tive colours can be implemented in the controller, hook block 1, crane structures or in surrounding structures. In yet another embodiment, the markings may have a background col- our to emphasize the colour of the markings, for example with an opposite colour. For example, letter N is in black colour and has a white background colour, or letter S is in yellow colour and has a purple background colour. Letters may also be re- placed by shapes. However, different shades of red and green as opposite colours are not recommended to use due to common vision deficiency. In yet another em- bodiment, as illustrated in Figure 10 in a very simplified manner, the letters may be in black colour, but the background colours are different. For example, the letter S is in black colour and has the background colour light blue, while the letter E is in black colour and has the background colour orange. In yet another embodiment, the markings may include an additional in- dication 51 of the direction which further visualizes which direction the marking is moving away from. The additional indication 51 may be a crescent or line or smaller marking indicating opposite direction, having a same or different colour than the background colour and / or the marking colour, next to the letter or shape, as illustrated in Figure 11 in a simplified manner. For example, the letter S is in black colour and has a background colour light blue and the additional indication 51 colour purple, while letter E is in black colour and has a background colour or- ange and the additional indication 51 colour green. The user may realize without looking at all driving directions and guide the hook block 1 faster away from the user. In an embodiment, the visually observable or readable means 5 may be sticky labels, such as stickers, which are easily attachable and removable. Manufac- turing such labels are also inexpensive. In another embodiment, the visually observable or readable means 5 may be spreadable substance, such as paint. The paint may also contain fluorescent or phosphorescent pigments, so that the visually observable or readable means 5 may be visible in the dark. In yet another embodiment, the visually observable or readable means 5 may be nonplanar. The nonplanarity may be arranged as integrated part of the casing, for instance by engraving or metal stamping. The nonplanarity may alter- natively be arranged as a separate part attachable to the casing, for instance by welding or using a fastener. In the above embodiments, the visually observable or readable means 5 are located on the hook block 1 in such a way that they are visible from the sides or from a worm’s eye point of view. The visibility of the visually observable or read- able means 5 are preferably seen in different height positions, such as downwards, to the side and upwards. When a maintenance person is at the same level as the main girder 13, he or she will have difficulties to see the markings on the bottom surface of the main girder 13 but won’t have restrictions to look downwards at the visually observable or readable means 5 of the hook block 1 when the visually ob- servable or readable means 5 can be detected from a bird’s eye point of view. The controller can be a wireless and portable device nowadays. During the mainte- nance the hook block 1 is typically driven to the top position in order to check the top hoisting limit. The controller is then usually used by the maintenance person due to safety reasons so that the crane can not be operated during the maintenance from the ground level. However, an additional set of visually observable or readable means 5 may also be located on the hook block 1 in such a way that they are visible from the above or from a bird’s-eye point of view. For instance, they can be arranged on the top surface of the casing 2. The additional set of the visually observable or readable means 5 may similarly indicate the movable horizontal direction with same mark- ings. The aim of the present invention is to provide an ergonomic and cost- effective solution for detecting the correct direction to which the hook block 1 is desired to be moved. The crane operator uses the controller for moving the hook block 1 but due to constant movement around the hook block, he / she may easily become disorientated when trying to decide the correct direction and has to check the desired direction from the main girder. When the markings are located on the bottom surface of the main girder 13, they can be inconvenient and difficult to out- line due to the strong and dazzling lights which are arranged near the ceiling. With the implementation of the present invention, the crane operator can see the visu- ally observable or readable means 5 as direction markings right in front of him / her without needing to lift his / her head and trying to distinguish the direction mark- ings on the bottom surface of the main girder. The crane operator can save time and avoid dangerous situations by seeing the direction markings which would in- dicate which direction the peripheral surface of the hook block is facing towards and avoid attempting to guess the correct direction by trial and error, which is not sensible in narrow spaces as the load may collide with other loads or shelf struc- tures or even other staff. The hoisting rope 15 is usually threaded at least twice up-and-down be- tween the rope hoist 10 and the hook block 1, and forms a rigging that resists twist- ing around the vertical axis, whereby the visually observable or readable means 5 on the hook block 1 maintain their direction as long as the hook block 1 is sup- ported by the hoisting ropes 15. If a hook block 1 is removed from the hoisting ropes 15 when changing the rope, it is possible to lift the hook block 1 to other way round, with a 180-degree phase shift and the visually observable or readable means 5 deviate from the intended directions. The visually observable or readable means 5 can be also arranged on the main girder 13, for instance on the bottom surface of the main girder 13, in which case the aforementioned problem is avoided. The visually observable or readable means 5 may additionally locate on the top surface of the main girder 13 so they are visible to a maintenance worker when working on or beside the main girder 13. It is to be understood that the above description and the accompanying figures are only intended to illustrate the present invention. It will be obvious to a person skilled in the art that the invention can be varied and modified without de- parting from the scope of the invention.

Claims

CLAIMS 1. A hook block (1) for a crane, comprising at least one casing (2) covering at least partially one rope pulley, a load hook (3) connected to the casing (2) for lifting load, the hook block (1) is movable in at least one horizontal direction, c h a r a c t e r i z e d in that the hook block (1) further comprises visually observable or readable means (5), wherein the visually or readable means (5) indicates a movable hori- zontal direction.

2. The hook block according to claim 1, wherein the visually observable or readable means (5) are sticky labels.

3. The hook block according to claim 1, wherein the visually observable or readable means (5) are spreadable substance, such as paint.

4. The hook block according to claim 1, wherein the visually observable or readable means (5) are nonplanar.

5. The hook block according to claim 4, wherein the nonplanarity is ar- ranged as integrated part of the casing (2).

6. The hook block according to claim 4, wherein the nonplanarity is ar- ranged as separate part attachable to the casing (2).

7. The hook block according to any preceding claims 1-6, wherein the at least one casing (2) comprises four peripheral surfaces (6, 7, 8, 9), wherein a first peripheral surface (6) and a third peripheral surface (8) are towards opposite di- rections, and a second peripheral surface (7) and a fourth peripheral surface (9) are towards opposite directions, perpendicular to the direction of the first periph- eral surface (6) and the third peripheral surface (8), and the visually observable or readable means (5) are arranged on each of the four peripheral surfaces (6, 7, 8, 9).

8. The hook block according to claim 7, wherein the four visually ob- servable or readable means (5) indicate four movable horizontal air directions.

9. The hook block according to claim 8, wherein the air directions are indicated using SFS standard markings with shapes rectangle, circle, triangle and square.

10. The hook block according to claim 8, wherein the air directions are indicated using ANSI standard markings with letters N, E, S, W.

11. The hook block according to claim 8, wherein the air directions areindicated using DIN standard markings with arrows pointing up, right, down and left.

12. A crane, comprising a main girder (13), a rope hoist (10), arranged to move along the main girder (13), com- prising a rope drum (12) for a hoisting rope (15) to be winded thereon, and the hook block (1) according to any preceding claims connected to the rope hoist (10) via the hoisting rope (15).

13. The crane according to claim 12, wherein the main girder (13) is movable on rails (14), wherein the main girder (13) is supported by said rails (14) at its ends, 14. The crane according to claim 12 or 13, wherein the crane is an over- head bridge crane or a gantry crane.

15. The crane according to claim 12, wherein the crane is a wall jib crane.

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