[0001 ] The present invention relates to a device for preventing undesired release of safety hooks, as well as a system for the same.

Background art

[0002] Hooks carrying a load are used in a number of applications, and such hooks are generally divided into hooks that can be disengaged from the load they carry only when the force applied by the load is relieved from the hook, and hooks that can also be disengaged from the load while the load still applies a force on the hook.

[0003] An exemplary area of application for hooks is the offshore and shipping industry.

[0004] For a lifeboat being launched the consequences can be fatal if the

suspension hook that keeps the lifeboat suspended is prematurely released while the boat is still hanging above water level. It is therefore considered advantageous to have a release system that does not allow the hook to open if the boat is not already floating on the water, so that the hook is substantially unloaded. Therefore, hooks working in this manner are referred to as OFF-LOAD hooks.

[0005] Nevertheless, in emergency cases it has been seen that lifeboats that have been safely lowered to the water surface still exert a tensile load on the hook. In the case of OFF-LOAD hooks, this could lead to fatal consequences as the lifeboat cannot be disengaged from a sinking ship and the ship therefore will also sink the lifeboat. For this reason, hooks have been developed that are also able to disengage a load when subject to loading. Hooks having such release mechanisms are referred to as onload hooks.

[0006] An exemplary on-load hook is described in EP 1512621 B. An exemplary OFF-LOAD/on-load hook is shown and discussed in a product brochure from Survival Craft Inspectorate, entitled "Lifeboat and Lifesaving

Equipment, Manufacture, Inspection and Maintenance." [0007] In the last few years there have been numerous accidents during training and work with lifeboats due to premature release of on-load suspension hooks. New regulations intended for preventing such unintended release have been composed. This is to ensure that the on-load hooks are designed in such a manner that, as far as possible, unforeseen situations are prevented from occurring when lowering, recovering or working with lifeboats aboard ships. However, a total of at least 30,000 lifeboat hooks of different types exist that don't comply with the new regulations.

[0008] Hence, it is a desire of providing a device for preventing unwanted release of load from ON-LOAD hooks.

[0009] It is also an aim of the present invention to form said device in such a

manner that an unstable on-load hook can be made "safe" by way of simple measures. This means that the hooks shall not release

unintentionally in any case of incorrect use and/or lacking/inappropriate maintenance.

[0010] A further aim of the present invention is to make sure that the lock cannot be incorrectly installed or operated in any manner. The lock must be able to resist release forces due to "disengagement" attempts and at the same time be able to withstand a hook falling outside of its tolerance range.

[001 1 ] Additionally, the solution must not involve any intervention in the hook

design that may affect the structural aspects thereof and thereby reduce the overall strength of the hook. This would require additional testing of each individual hook, which would be impossible in practice.

Summary of the invention

[0012] It is an object of the present invention to provide a securing device for onload hook arrangements as well as a safety assembly comprising parts configured for engagement with the securing device.

[0013] According to the present invention, a securing device adapted for

preventing unintended release of load from on-load safety hooks is provided, said securing device at least including:

• A first manually releasable securing member configured for engaging a hook housing through at least one engagement means. • At least one securing means that makes sure the securing member is maintained in a fixed position relative to a release mechanism and engaged with the release mechanism provided in the hook housing.

[0014] According to an aspect of the invention, the first securing member is

formed as a sleeve having internal sidewalls adapted to the external surface at the one end of the release mechanism protruding from the hook housing.

[0015] According to a second aspect of the invention, the first securing member has an arrow-shaped external circumference.

[0016] According to a further aspect of the invention, in any combination of the above aspects, the securing member is characterized in that it is configured for engagement with a hook housing through at least one engagement means, the securing member being provided with at least one means for receiving said engagement means.

[0017] According to a still further aspect of the invention, in any combination of the above aspects, the securing member is characterized in that the securing member includes one means for receiving one engagement means.

[0018] According to a still further aspect of the invention, in any combination of the above aspects, the securing member is characterized in that the securing member includes one means for receiving one engagement means, wherein the engagement means is a pin formed with an eye at the one end thereof, the eye being adapted for attachment of a wire end, the pin, as received in the means, protruding outwardly so that the pin is adapted for engagement with a complementary hole formed in the hook housing.

[0019] According to a still further aspect of the invention, in any combination of the above aspects, the securing member is characterized in that the securing member includes means for receiving at least one securing means.

[0020] According to a still further aspect of the invention, in any combination of the above aspects, the securing device is characterized in that the securing member includes means for receiving one securing means, the securing means being a securing pin configured for engagement with the securing member by way of associated holes formed in the securing member.

[0021 ] According to a still further aspect of the invention, the securing pin is

characterized in that the securing pin is formed with a curved section, the curved section being adapted to a corresponding curved section of the first securing member so that when the securing pin is appropriately locked, said curved sections will engage to prevent undesired movement of the securing pin.

[0022] According to the present invention, a safety assembly for preventing

unintended release of load from on-load safety hooks is also provided, the safety assembly at least including:

• A first securing member configured for engagement with a hook

housing through at least one engagement means and configured for engagement with a first end of a release mechanism.

• At least one securing means making sure the securing member is retained in a fixed position relative to the release mechanism, the release mechanism being configured for releasing a hook body and the release mechanism being rotatably arranged in the hook housing.

• A releaser arm configured to mount at a second end of the release mechanism.

• A nut ensuring that the releaser arm is secured against the release mechanism.

[0023] According to an aspect of the invention, the securing member includes one means for receiving one engagement means, the engagement means being a pin, with the pin mounted in the means protruding outwardly so that the pin is configured for engagement with a complementary hole in the hook housing.

[0024] According to a second aspect of the invention, the at least one securing means is a single securing pin shaped so as to fit into a receiving hole formed in the securing member when the securing member engages the release mechanism, the securing pin being further configured for engaging a groove in the release mechanism, so that the securing member is locked to the release mechanism in an axial direction.

Brief description of the drawings

[0025] To facilitate the understanding of the invention the following description will refer to the appended drawings, in which

[0026] Fig. 1 a shows a prior art on-load hook/release mechanism in a suspended state,

[0027] Fig. 1 b illustrates the hook of Fig. 1 a during the release process,

[0028] Fig. 2 shows an on-load hook assembly in which a release shaft and the safety nut thereof are shown separated from the hook housing

[0029] Fig. 3 shows an exemplary securing device according to the invention and a safety assembly for preventing unintended release of load from on-load safety hooks according to an aspect of the invention,

[0030] Fig. 4 shows an exemplary securing member according to the present invention,

[0031 ] Fig. 5 shows an example of the securing member of Fig. 4 according to the present invention wherein an engagement means is mounted to the securing member,

[0032] Fig. 6 shows an exemplary engagement means configured for

engagement in a hook housing,

[0033] Fig. 7 shows an exemplary securing pin configured for engagement with a safety element according to an aspect of the present invention,

[0034] Fig. 8 shows an exemplary securing device according to the present

invention,

[0035] Fig. 9 shows an exemplary release shaft according to the present

invention,

[0036] Fig. 10 shows an exemplary releaser arm according to the present

invention,

[0037] Fig. 1 1 shows an exemplary arrow member according to an aspect of the present invention,

[0038] Fig. 12 shows a nut adapted for attachment and fixation of the release shaft shown in Fig. 9, [0039] Fig. 13 shows a hook housing having a safety assembly according to an aspect of the present invention,

[0040] Fig. 14a shows an exemplary hook assembly according to an aspect of the present invention, wherein the securing member is not engaged with the release shaft, and

[0041 ] Fig. 14b shows an exemplary hook assembly according to an aspect of the present invention, wherein the securing member is engaged with the release shaft.

Embodiments of the invention

[0042] In the following, the present invention will be explained by describing

preferred embodiments, referring to the attached drawings. However, a person skilled in the art will recognize other applications and modifications within the scope of the invention, as defined in the appended independent claims.

[0043] The terms cam shaft, release shaft, and release mechanism are used

interchangeably throughout the description.

[0044] Fig. 1 a shows a principle view of an on-load hook assembly. From the figure it can be seen that a load E exerts a force s on a hook H. As the force S is not acting through the point of rotation of the hook body H, the force will result in a rotation of the hook body H about a point of rotation Q. The rotation is prevented in that the hook body H abuts against a locking device X. Hence, X will prevent or allow release of the hook under loading in that X can be rotated about a point Z. Fig. 1 b shows the hook body in a released position.

[0045] In practical implementations, locking device X may be a cam shaft, for example, in which case hook body H would abut against the cam in a locked position while the hook body would be freely rotatable about the cam shaft so that the tail end of the hook body no longer engages the cam shaft.

[0046] As indicated, unintentional rotation of the cam/release shaft has resulted in inappropriate release of load. It is therefore a need for preventing such release, or alternatively to prevent release by way of other release principles.

[0047] According to the present invention, a device 1 is provided which prevents accidental disengagement in that a cam shaft that normally locks the hook body is secured against rotation.

[0048] The device 1 preventing accidental release of load in that the cam shaft, or another type of release shaft, rotates is configured so that the device is rotationally locked to the hook housing, and the device is further configured so that when it has been mounted to the cam/release shaft, the device and shaft cannot rotate independently of each other. That is, the device is rotationally locked to the cam/release shaft. The rotational lock between the shaft and locking device may be implemented in a number of manners as known by the person skilled in the art, e.g. by way of a nut with splint, nut with set screw, splines, interference fit, and tapered fit, or, as shown in the embodiment of Fig. 3, in that the sections of device 1 and shaft are not round. The former solutions for preventing rotation may have some associated disadvantages with respect to disengagement of securing device 1 .

[0049] As mentioned, the securing device is prevented from rotating relative to the hook housing in that the device, in a locked condition, is engaged with the hook housing. The securing device is provided with at least one protruding pin, the pin being configured for engagement with a

corresponding number of holes/openings formed in the hook housing, which engagement prevents rotation of the shaft/securing device assembly.

[0050] In order to be able to release the load intentionally, it must be possible to disengage the securing device from the cam/release shaft. The securing device is hence provided with holes adapted for receiving one or more cotter pins, the cotter pins being fit to respective grooves in the

cam/release shaft. Removing the at least one cotter pin allows the securing device to be pulled off the cam/release shaft, after which the shaft can be rotated so that the hook body can be rotated to disengage the load. [0051 ] The person skilled in the art will be familiar with a number of solutions for securing axial movement of the securing device. In the present context, it is essential that the arrangement is secure, intuitive, and that an operator can easily remove the at least one cotter pin.

[0052] The securing device, together with the at least one cotter pin, must be configured for rotation locking against the cam/release shaft and hook housing. Hence, the securing device may be considered as part of a system in which certain prerequisites must be met in order for a desired functionality to be achieved.

[0053] The system comprises the shaft, which must be configured for

engagement with the securing device and the at least one pin/splint, as well as the hook housing, which must be provided with one or more means securing the engagement with the securing device.

[0054] Additionally, the system must be constructed so that the shaft is rotatable, i.e. it needs to be rotatably mounted through the hook housing and must also be provided with a release means for allowing rotation, which means may be provided in the form of an arm fixed at an end of the release shaft accessible to an operator.

A first embodiment of a securing device according to the invention

[0055] A first embodiment of the securing device according to the present

invention will now be described with reference to the drawings. In Fig. 3, the securing device is shown together with other parts which together form a system for releasing and for preventing the accidental release of load. The securing device itself is comprised by a few components, as shown in Fig. 3 at the lower left corner. According to this embodiment, the securing device includes four structural parts. These can be clearly seen in Fig. 8. In the following, the arrow-shaped device 1 configured for engagement with a release/cam shaft is referred to as the first securing member 1 . In addition to the first securing member, the securing device according to the first embodiment comprises a cotter pin 82, 72 or securing pin 82, 72. In the following, the terms cotter pin, securing pin and splint 72, 82 are used interchangeably. Also shown is a thin wire 83 attached to splint 82, 72 and a protruding pin 62. The purpose of the thin wire is to make sure the cotter pin 82, 72 will not be lost. A ribbon 85 is attached at the upper end of splint 82, 72 to facilitate disengagement of splint 82, 72. Fig. 4 shows the first securing member in more detail. It is seen that the first securing member is provided with an opening 45 for receiving a pin 62. It is this protruding pin that is adapted for and brought into engagement with a hole formed in the hook housing so that the release/cam shaft is not rotatable. It is also seen that the first securing member is shaped as a fixed arrow, which shape is functional in the sense that it clearly displays to an operator the current position of the release/cam shaft. If the arrow points upwards, according to an embodiment, it indicates that the hook has been disengaged for release. It is also seen that the first securing member 1 is provided with an opening which is not a regular circle, which opening is complementary and congruous to the one end of the cam/release shaft. The cam shaft adapted for this embodiment is shown in Fig. 9. Also shown in Fig. 4a is a member 1 b having same shape as first securing member 1 , which member 1 b is a "shell" adapted to and surrounds the first securing member 1 . Shell or member 1 b may protect the first securing member 1 , but more importantly it is made in a conspicuous colour so that the securing device appears as easily noticeable. Openings, the holes 46 are adapted for the thickness of securing pin 72, 82 so that it can be entered into hole 46. Securing pin 72, 82 is depicted more clearly in Fig. 7. It can be seen that the securing pin is formed with a curved section, which curved section is adapted to a corresponding curved section of the first securing member 1 and shell 1 b. When the securing pin is properly locked, said curved sections will engage to prevent unwanted movement of the securing pin.

[0056] An exemplary protruding pin 62 is shown in Fig. 6. In other embodiments, it is contemplated that several pins can be used or that one or more pins have another shape, the essential herein being that proper rotation prevention relative to the hook housing in which the protruding pin or pins are to be engaged is achieved.

[0057] As indicated above, other embodiments of the securing device could

engage the cam/release shaft in another manner, such that by way of splines or the like; the principle is upheld as long as the securing device/first securing member ensure a simultaneous, synchronous rotation when they are engaged. Also, the securing pin may be replaced with other types of splinters which, for example, run through the securing member and an outer end of the cam/release shaft.

A first embodiment of a system configured for rotational protection of the release/cam shaft according to the invention

[0058] A first embodiment of a system configured for rotational protection of the release/cam shaft according to the present invention will now be described with reference to the drawings. The system is illustrated in Fig. 3, which shows exemplary parts that can be replaced in an on-load hook to allow the hook to be secured by means of a securing device according to the invention. It is seen that the system comprises a release/cam shaft, an arrow-shaped disk 6, a releaser arm 5, a nut 4, and a set screw 9 for nut 4. The individual components of the system will now be described separately.

[0059] Cam shaft 3 is depicted in more detail in Fig. 9. It can be seen that the cam shaft is provided with a cam section 92 configured for engagement with the tail end of a hook body. Also seen is a groove 93 configured for engagement with securing pins 72, 82. Further shown is a flange located adjacent to section A-A, which flange forms an abutment face against the hook housing. Further seen from Fig. 9 is that cam shaft 3 is provided with external threads at the outer end opposite to the end configured for engagement with the securing device. Adjacent to the thread area there is a region configured for engagement with a releaser arm 5. The cross- section of this area is given by section E-E of Fig. 9. Section A-A of Fig. 9 is adapted for the shape of an opening in an arrow member 6 as shown in more detail in Fig. 1 1 . Arrow member 6 primarily serves as a marker which at any given time indicates the current position of cam shaft 3. This member hence has a very important function as an operator, in a quick glance, can easily ascertain the current position of the release/cam shaft. The system is further provided with grease nipples as denoted in Fig. 3 as element 2 or 8. [0060] Releaser arm 5 is shown in Fig. 10, wherein it is seen that the internal shape of the shaft opening therein is adapted for the section depicted at E- E in Fig. 9. The releaser arm is tread onto the end of cam shaft 3 that protrudes beyond the hook housing, and then the arm is secured in that nut 4 is screwed onto the threaded area of the cam shaft. Nut 4, in turn, is secured by a set screw 9.

[0061 ] Fig. 13 shows a complete hook assembly including a system for

preventing unintended release of load on on-load hooks according to the present invention, with no securing device attached.

[0062] Fig. 14a shows the hook assembly of Fig. 13 fully assembled with no

securing device installed. Fig. 14b shows a complete hook assembly with the securing device installed.

Definitions and reference numerals

1 Securing device, comprising a securing pin and the other components necessary for the intended function b A cover, shell adapted for the shape of the first securing

member

2 Grease nipple

3 Cam shaft / release shaft / release mechanism, which

shaft/mechanism, in principle, needs not include a cam; what is essential according to the present invention is that the shaft can be secured against rotation by a securing device 1

4 Nut, adapted to a threaded area of the shaft 3 and adapted to a set screw 9

5 Releaser arm configured for being able to rotate/turn shaft 3

6 Arrow member serving as an indicator for the position of shaft 3.

It is seen that the opening has the same shape as section A-A of cam shaft 3

7 Adapter for attachment of grease nipple 8

8 Grease nipple

9 Set screw for nut 4

45 Opening in the first securing member adapted to a protruding pin 52, 62

46 Opening in the first securing member, adapted for the

configuration of securing pin 72, 82

52 Pin eye for safety wire for engagement in hook housing

62 Pin for engagement in hook housing

72 Cotter pin for securing the first securing member

82 Cotter pin for securing the first securing member

83 Securing wire, preventing loss of cotter pins 72, 82

85 Ribbon for facilitating disengagement of cotter pin 72, 82

92 Cam surface of cam shaft 3

93 Grooves configured for engagement with cotter pins 72, 82

129a Threaded screw hole in nut 4 for set screw 9