A connecting rod type self-locking mechanism for a boat cradle

Abstract

The invention discloses a connecting rod type self-locking mechanism for a davit. The davit is provided with a self-locking mechanism, which is connected to shaft bodies arranged at the centers of both sides of a movable pulley. The self-locking mechanism comprises connecting rods I, II and III. The connecting rods I and II are in an L-shape. An arc notch is arranged at the intersection of the long side and the short side of the connecting rod I. The middle part of the long side of the connecting rod I is hinged to the davit at point A. The top of the long side of the connecting rod I is hinged to the top of the long side of the connecting rod II at point B. The long side of the connecting rod II and the connecting rod III are both arc-shaped. The inner arc of the connecting rod II is fitted with the outer arc of the connecting rod III. The short side of the connecting rod II is hinged to the left end of the connecting rod III at point C. The right end of the connecting rod III is hinged to the davit at point D. A threading eye plate is arranged at the bottom of the long side of the connecting rod II. One end of the control rope is connected to a lifting ring on the davit, and the other end successively passes through a pulley on a hull structure, the threading eye plate, and a pulley at the bottom of the davit, and is finally connected to a remote control locking protection device.

Description

Technical Field

[0001] The invention relates to a connecting rod type self-locking mechanism for a cradle. Background Art

[0002] There is a davit arrangement as shown in the following Figure 1 As shown, it is installed on the hull cabin roof structure and is used to retract and launch the lifeboat. It is the main load-bearing device of the lifeboat and also the storage and fixing device of the lifeboat.

[0003] The davit is wound with a lifting wire rope, one end of which is connected to the drum of the lifting winch through a guide pulley; the other end is also connected to the eye plate at the end of the davit through a guide pulley; and then connected to the lifeboat through a movable pulley connecting ring. When the winch drum is lifted and rotated, the movable pulley will drive the lifeboat to rise and eventually reach the highest position of the davit, which is the storage position of the lifeboat. However, if this state is maintained, the lifting wire rope of the davit will always be in a tensioned state, which will directly affect the service life of the lifting wire rope.

[0004] In order to extend the service life of the lifting wire rope, a mechanism needs to be invented, which can replace the lifting wire rope to bear the load of the lifeboat and reliably self-lock it when the lifeboat is stored, so that the lifting wire rope can be unloaded. When encountering an emergency, the mechanism can be quickly opened without affecting the retrieval and deployment of the lifeboat. Summary of the invention

[0005] The purpose of the present invention is to solve the above deficiencies in the prior art and to provide a connecting rod type self-locking mechanism for a davit.

[0006] A connecting rod type self-locking mechanism for a davit comprises a davit, wherein the davit is fixed to a hull structure, an end eye plate is arranged at the tail of the davit, one end of a weight-lifting wire rope is tied to the end eye plate, the other end of the weight-lifting wire rope passes through an angle pulley at the head of the davit, then passes around a movable pulley below the angle pulley, and passes through a fixed pulley behind the angle pulley to be connected to a drum of a lifting winch, the structures arranged on the left and right sides of the davit are symmetrical, a self-locking mechanism is arranged on the davit, and the self-locking mechanism is connected to an axle body arranged at the center of both sides of the movable pulley, the self-locking mechanism comprises connecting rods I, II and III, the shapes of connecting rods I and II are L-shaped, and the connecting rods III and III are L-shaped. An arc-shaped notch is provided at the intersection of the long side and the short side of rod I, the middle part of the long side of connecting rod I is hinged to the cradle at point A, the top of the long side of connecting rod I is hinged to the top of the long side of connecting rod II at point B, the long side of connecting rod II and connecting rod III are both arc-shaped, the inner arc of connecting rod II fits with the outer arc of connecting rod III, the short side of connecting rod II and the left end of connecting rod III are hinged to point C, the right end of connecting rod III is hinged to the cradle at point D, and a threading eye plate is provided at the bottom of the long side of connecting rod II, one end of the control rope is connected to the lifting ring on the cradle, and the other end passes through the pulley on the hull structure, the threading eye plate, the pulley at the bottom of the cradle, and finally is connected to the remote control locking protection device.

[0007] As a further improvement, a lifting ring is provided at the bottom of the movable pulley, and the lifting ring is connected to the lifeboat.

[0008] As a further improvement, the end eye plate is connected to the cradle by welding or by bolts.

[0009] As a further improvement, the hinges of the connecting rod are coated with grease.

[0010] As a further improvement, the materials of the connecting rod I, connecting rod II and connecting rod III are all stainless steel.

[0011] As a further improvement, the surfaces of the connecting rods I, II and III are all coated with anti-rust primer. Beneficial Effects

[0012] The invention is cleverly designed. The new type of connecting rod self-locking mechanism cleverly utilizes its own structural form. When the device is stored, it can effectively bear the load and form a self-locking state, so that the lifting wire rope can be unloaded. No matter how the load changes, the mechanism cannot be opened by relying on the deadweight of the load. When the self-locking mechanism needs to be opened, the connecting rod II must be manually turned clockwise to a certain angle. In addition, the entire process of the self-locking mechanism rotating will not interfere with the movable pulley shaft, and will not affect the retrieval and deployment of the lifeboat. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the overall structure of a connecting rod type self-locking mechanism for a davit;

[0014] Figure 2 This is the principle diagram of the locking state of the connecting rod type self-locking mechanism;

[0015] Figure 3 This is the principle diagram of the dead point state of the connecting rod type self-locking mechanism;

[0016] Figure 4 This is the schematic diagram of the open position of the connecting rod type self-locking mechanism;

[0017] Figure 5 It is the force principle diagram;

[0018] 1. End eye plate 2. Hull structure 3. Frame 4. Lifting wire rope 5. Angle pulley 6. Self-locking mechanism 7. Movable pulley 8. Fixed pulley 9. Connecting rod I 10. Connecting rod II 11. Connecting rod III 12. Movable pulley shaft 13. Limit stop rod. DETAILED DESCRIPTION

[0019] In order to deepen the understanding of the present invention, the present invention will be further described in detail below in conjunction with embodiments and drawings. The embodiments are only used to explain the present invention and do not constitute a limitation on the protection scope of the present invention.

[0020] like Figures 1 to 5 As shown, a connecting rod type self-locking mechanism for a davit includes an end eye plate 1, a hull structure 2, a davit 3, a lifting wire rope 4, an angle pulley 5, a self-locking mechanism 6, a movable pulley 7, a fixed pulley 8, a connecting rod I9, a connecting rod II10, a connecting rod III11, a movable pulley shaft 12 and a limit stop rod 13.

[0021] There are two sets of this connecting rod type self-locking mechanism, which are installed on the left and right sides of the davit boom structure, arranged symmetrically, and mainly composed of connecting rod I, connecting rod II and connecting rod III, and the three connecting rods are arranged in the same plane. Among them, connecting rod I and connecting rod II are hinged at point B; connecting rod II and connecting rod III are hinged at point C, and the inner arc of connecting rod II can fit the outer arc of connecting rod III; connecting rod I is hinged to shaft A fixed on the davit; connecting rod III is hinged to shaft D fixed on the davit.

[0022] Force analysis:

[0023] When the load G is hung on the arc-shaped notch of connecting rod I, connecting rod I of the self-locking mechanism hooks the two ends of the shaft of the movable pulley (equivalent to bearing the load), and connecting rod I is subjected to the vertical downward force of G. Connecting rod I tends to rotate clockwise around axis A, and at this time it may drive connecting rod II to rotate clockwise or counterclockwise around the hinge point B.

[0024] If connecting rod II rotates counterclockwise around hinge point B, connecting rod III will also rotate counterclockwise around axis D due to the action of connecting rod II. However, because the inner arc of connecting rod II is matched with the outer arc of connecting rod III in the design, and connecting rod II and connecting rod III are in the same plane, connecting rod II and connecting rod III cannot actually rotate counterclockwise, forming a self-locking. Therefore, connecting rod II can only rotate clockwise around hinge point B, and drive connecting rod III to rotate clockwise around axis D.

[0025] Reanalyze the attached Figure 2 , the straight line connecting the two points BD is LL, the straight line connecting the two points CD is MM, and the angle between the straight lines LL and MM is α. It can be observed that the hinge point C of the connecting rod II and the connecting rod III is below the straight line LL. At this time, the connecting rod mechanism can actually be regarded as a quadrilateral of ABCDA. Assume that a person actively moves the connecting rod II and drives the connecting rod III to rotate slowly clockwise around the axis D (such as Figure 2 Neutral force F), when point C falls on line LL (see Figure 3 ), in this case the linkage can be viewed as an ABCA triangle, and the triangle is stable (see Figure 5 ), the connecting rod mechanism will be locked. At this time, no matter how the value of G changes, the connecting rod mechanism will not rotate.

[0026] Continue to actively move connecting rod II and drive connecting rod III to slowly rotate clockwise around axis D (such as Figure 4The middle force F), at this time, the angle between the straight line MM and the straight line LL is β, which will also cause the connecting rod I to rotate clockwise. In fact, as long as the angle β>0, the deadweight of G can drive the connecting rods I, II, and III to rotate clockwise respectively, until the rotation of the connecting rod I hits the limit lever. At this time, the rotation angle of the connecting rod I is γ, and the angle γ must fully meet the lowering of the movable pulley and the load, and after rotating at an angle of γ, the connecting rod I will not interfere with the movable pulley shaft.

[0027] In summary, when the hinge point C is below the straight line LL, connecting rod II and connecting rod III in the linkage mechanism tend to rotate counterclockwise, and the mechanism is self-locking.

[0028] When the hinge point C is on the straight line LL, the linkage mechanism forms a triangle, which is a dead point and the mechanism is self-locking.

[0029] When the hinge point C is above the straight line LL, the connecting rods II and III in the linkage mechanism tend to rotate clockwise, and the mechanism will be opened.

[0030] The hinge point C must pass an angle α from the storage state to the open state, and no matter how the load changes, the mechanism cannot be rotated by the load's own weight. Figure 1 The middle remote control cable pulls the eye plate of connecting rod II clockwise to proceed.

[0031] In the storage state, in order to ensure that the self-locking mechanism connecting rod II does not accidentally rotate clockwise due to factors such as vibration, a remote control cable can be set to pull the self-locking mechanism downward to play a protective role.

[0032] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A connecting rod type self-locking mechanism for a davit, comprising a davit, the davit being fixed on a hull structure, an end eye plate being provided at the tail of the davit, one end of a weight-lifting wire rope being tied to the end eye plate, the other end of the weight-lifting wire rope passing through an angle pulley at the head of the davit, then passing around a movable pulley below the angle pulley, and passing through a fixed pulley behind the angle pulley to be connected to a drum of a lifting winch, characterized in that: A self-locking mechanism is provided on the cradle, and the self-locking mechanism is connected to the shaft body arranged at the center of both sides of the movable pulley. The self-locking mechanism includes connecting rod I, connecting rod II and connecting rod III. The shape of connecting rod I and connecting rod II is L-shaped. An arc groove is provided at the intersection of the long side and the short side of connecting rod I. The middle part of the long side of connecting rod I is hinged to the cradle at point A, and the top of the long side of connecting rod I is hinged to the top of the long side of connecting rod II at point B. The long side of connecting rod II and connecting rod III are both arc-shaped, and the inner arc of connecting rod II is fitted with the outer arc of connecting rod III. The short side of connecting rod II is hinged to the left end of connecting rod III at point C, and the right end of connecting rod III is hinged to the cradle at point D. A threading eye plate is provided at the bottom of the long side of connecting rod II. One end of the control rope is connected to the lifting ring on the cradle, and the other end passes through the pulley on the hull structure, the threading eye plate, and the pulley at the bottom of the cradle in turn, and is finally connected to the remote control locking protection device.

2. A connecting rod type self-locking mechanism for a davit according to claim 1, characterized in that: A lifting ring is arranged at the bottom of the movable pulley, and the lifting ring is connected with the lifeboat.

3. A connecting rod type self-locking mechanism for a davit according to claim 1, characterized in that: The end eye plate is connected to the cradle by welding or by bolts.

4. A connecting rod type self-locking mechanism for a davit according to claim 1, characterized in that: The hinges of the connecting rods are coated with grease.

5. The connecting rod type self-locking mechanism for a davit according to claim 1, characterized in that: The materials of the connecting rod I, connecting rod II and connecting rod III are all stainless steel.

6. A connecting rod type self-locking mechanism for a davit according to claim 1, characterized in that: The surfaces of the connecting rods I, II and III are all coated with anti-rust primer.

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