pulley

Abstract

A pulley block is disclosed. The pulley block comprises: a first plate (10) and a second plate (12), and a pulley (30) sheave arranged between the plates, the pulley sheave being adapted to rotate on bearings on sheave shafts (40, 42), the sheave shafts extending between the plates along the sheave axis. The plates are connected to the sheave shafts so as to allow one plate to rotate relative to the other plate about the sheave axis between a closed position of the pulley block and an open position of the pulley block. Each plate has a corresponding bollard structure at a position away from the sheave axis, the bollard structures being arranged so that when the plates are in the closed position, the corresponding bollard structures are in contact with or in close proximity with each other to form bollards extending between the plates. When the plates are in the open position, the corresponding bollard structures are spaced apart. The pulley sheave rotates on bearings on a sheave shaft assembly extending between the plates along the sheave axis. The assembly has: a spindle fixed to the first plate without rotation and free to rotate relative to the second plate; and a shaft cap clamping the spindle to the first plate, the shaft cap being removably fixed to the spindle.

Description

Technical Field

[0001] The present invention relates to pulley blocks. In particular, but not exclusively, the invention applies to impact block pulleys, but may also be applied to many other types of rope guide products. Background Art

[0002] Pulley blocks have a variety of applications in many different types of rope rigging, including but not limited to applications in climbing, rope access, rescue, industrial height safety, marine, heavy lifting and tightrope walking, sports, industrial and tactical fields. There are several terms closely associated with the word "pulley block", including "impact block", "impact pulley", "roller", "redirection", "traction block", "traction sheave", "lifting block", "tree stand block", "tail block", "marine block", "lifting pulley" (or just "pulley"), etc.

[0003] As with all equipment used in rope rigging, users require pulley blocks to be both strong and lightweight. These requirements are in some ways contradictory, as pursuing one aspect often compromises the other. The design of a pulley block has the additional challenge of maintaining an efficient rope configuration as a moving line is redirected over a rotating pulley sheave. Summary of the invention

[0004] The object of the present invention is to provide a pulley which improves upon the known pulleys taking these design objectives into account.

[0005] The main components of the pulley block are a first and a second spaced apart plate between which a sheave is carried for rotation about an axis generally orthogonal to the plates. In use, the plates are interconnected by fixed bollards spaced apart from the sheaves, the bollards generally having a cross-section that is circular about an axis parallel to the axis of rotation of the sheaves (or, at least, convex in its extent facing the sheaves), this shape being adapted to allow the line to slide smoothly over the bollards. Typically, the bollards can be unlocked, whereby the plates can rotate relative to each other about the sheave axis.

[0006] From a first aspect, the present invention provides a pulley block, the pulley block comprising:

[0007] a. The first plate and the second plate;

[0008] b. a pulley sheave disposed between the plates, the pulley sheave being adapted to rotate on a bearing on a sheave shaft extending between the plates along the sheave axis,

[0009] c. the plates are connected to the sheave shaft so as to allow one plate to rotate relative to the other about the sheave axis between a closed position of the block and an open position of the block, and

[0010] d. Each plate has a corresponding bollard structure at a position away from the axis of the sheave, the bollard structures being arranged so that when the plates are in a closed position, the corresponding bollard structures are in contact or close proximity with each other to form a bollard extending between the plates, and when the plates are in an open position, the corresponding bollard structures are spaced apart.

[0011] The bollard is thus formed from the structure of the two plates, rather than from separate components attached to one or both plates. This saves mass, simplifies manufacturing and increases strength compared to known pulley blocks. This also increases safety, as there are fewer parts to fail than with conventional pulley blocks. Once correctly configured and loaded, the loading mode pushes the pulley block into the closed position.

[0012] In the open position, a rope, attached sling or other line can be installed into the pulley block. When the pulley block is subsequently moved to the closed position, the line is constrained to move between the bollard and the sheave.

[0013] Typically, each bollard structure is integrally formed with the respective plate, for example as a one-piece cast and / or forged component.

[0014] Preferably, respective holes extend through each of the bollard structures (or through one bollard structure and partially through the other bollard structure), the holes being aligned with one another on the bollard axis when the pulley block is in the closed position. In such an embodiment, the pulley block can be secured in the closed position by inserting a locking member into the holes, thereby maintaining the holes aligned with one another.

[0015] Preferably, the bollard structures are shaped so that in the closed position a portion of one bollard structure overlaps and contacts a portion of the other bollard structure in a direction having a component parallel to the bollard axis. Preferably, the overlapping portions of the bollard structures have surfaces contacting each other orthogonal to the bollard axis. This has the effect of interlocking the bollard structures and preventing separation when the panels are subjected to lateral forces (in a direction tending to separate the panels), thereby increasing the strength and safety of the pulley block.

[0016] Wherein, in the closed position, preferably, the bollard structures together form a bollard with a convex cross-section in the direction facing the groove wheel. For example, in the closed position, the bollard structures can together form a bollard with a circular cross-section, but other smooth cross-sections can provide a suitable low friction surface.

[0017] From a second aspect, the present invention provides a pulley block, the pulley block comprising:

[0018] a. The first plate and the second plate;

[0019] b. a pulley sheave disposed between the plates, the pulley sheave being adapted to rotate on bearings on a sheave shaft assembly extending between the plates along the sheave axis,

[0020] c. the plates are connected to the sheave shaft assembly so as to allow one plate to rotate relative to the other plate about the sheave axis between a closed position of the block and an open position of the block, and

[0021] d. The sheave shaft assembly includes:

[0022] i. A spindle fixed without rotation relative to the first plate and freely rotating relative to the second plate;

[0023] as well as

[0024] ii. A shaft cap, which clamps the spindle to the first plate, and the shaft cap is detachably fixed to the spindle.

[0025] Such an arrangement enables an end user or service personnel to disassemble the shaft assembly, for example to perform maintenance.

[0026] Typically, the shaft cap engages with the spindle threads.

[0027] Each of the shaft cap and the spindle includes a shaft portion extending through corresponding through holes in the first and second plates. Each of the shaft cap and the spindle may include a head portion adjacent to surfaces of the first and second plates adjacent to the through holes, respectively.

[0028] The shaft assembly includes a spacer that spaces the head portion of the main shaft from the second plate in a direction parallel to the sheave axis. This prevents the second plate from being clamped onto the shaft assembly, which would result in its rotational movement being restricted.

[0029] In typical embodiments, the shaft cap is threadably engaged with the spindle.

[0030] Embodiments may further include a fixing mechanism to prevent the shaft cap from rotating relative to the first plate.Such a fixing mechanism is preferably removable to enable the shaft cap to be separated from the main shaft, thereby enabling the shaft assembly to be disassembled.

[0031] Embodiments of the second aspect of the invention may include features present in embodiments of the first aspect of the invention.

[0032] Preferably, each plate has a groove into which a portion of the sheave extends. This ensures that there is minimal clearance between the sheave and the plate and provides a smooth path for the wire to contact or leave the sheave. Typically, the groove is circular and centered on the sheave axis.

[0033] The shaft assembly is preferably hollow to provide a passage through the pulley block in a direction parallel to the axis of the sheave. Advantageously, the cross-section of the end portion of the passage is convex to provide smooth entry and exit for lines, webbing or other load-bearing components entering and leaving the passage.

[0034] Embodiments of the present invention may include two or more sheaves between plates, and may include more than two plates.

[0035] Most typically, the sheave is free to rotate in either direction, but may alternatively be constrained to rotate in a single direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Embodiments of the present invention will now be described in detail by way of example and with reference to the accompanying drawings, in which:

[0037] Figure 1 and Figure 2 is a front view of a pulley in a closed state embodying the present invention;

[0038] Figure 3 is Figure 1 A top view of an embodiment of the invention in a closed state;

[0039] Figure 4 corresponds to Figure 1 A front view of the unlocked state;

[0040] Figure 5 is corresponding to Figure 1 A front view of the device in an open state;

[0041] Figure 6 yes Figure 1 A top view of an embodiment of the invention in an open state;

[0042] Figure 7 is through Figure 1 A cross section of an embodiment of the present invention;

[0043] Figure 8 It is shown in detail Figure 1 A cross section of a sheave shaft assembly in an embodiment of;

[0044] Fig. 9 yes Fig. 9 An exploded view of the components of the shaft assembly;

[0045] Fig.10a and Fig.10b The use of a tool to secure the shaft cap to the spindle is shown;

[0046] Fig.11 A locking mechanism for preventing removal of the shaft cap is shown;

[0047] Fig.12 yes Figure 1An exploded view of a plate of an embodiment of the present invention;

[0048] Fig.13 yes Figure 1 Details of the bollard structure of the first plate of the embodiment;

[0049] Fig.14 and Fig.15 Details showing the locked and unlocked states Figure 1 A locking assembly of an embodiment;

[0050] Fig.16 and Fig.17 Shown for use with fixed and mobile ropes Figure 1 Embodiments of

[0051] Fig.18 Components of an embodiment of the present invention are shown, which embodiment is Figures 1 to 17 Variations of the embodiments; and

[0052] Fig.19 is through Fig.18 A partial cross section of an embodiment of the invention. DETAILED DESCRIPTION

[0053] With reference to the drawings, a pulley embodying the invention has a first plate 10 and a second plate 12. The plates 10, 12 have substantially similar peripheral shapes: they are formed by two arcuate portions, the first arcuate portion having a larger radius and extending from the sheave axis A. s The second arc part has a smaller radius and is centered on the bollard axis A. b Thus, each plate 10, 12 has a small boss portion 22, 22' and a large boss portion 24, 24' interconnected by an axis portion 26. The plates are arranged in a midplane P m The small boss portion 22 of the first plate 10 and the small boss portion 22' of the second plate 12 are each at the bollard axis A b The through hole on the first plate 10 is centered, the through hole of the first plate 10 is internally threaded, and the through hole of the second plate 12 is smooth. A cylindrical wall 28 surrounds the through hole of the small boss portion 22 ′ of the second plate 12 .

[0054] The sheave 30 is arranged between the plates 10, 12. The sheave 30 is mounted on rolling element bearings 32, 34 which enable the sheave to rotate about a sheave axis A centered about the through-holes of the large boss portions 24, 24'. s The bearings 32, 34 are mounted on a sheave shaft assembly which includes a main shaft 40, a shaft cap 42 and a shaft spacer 44. The sheave 30 has an outer working surface 36 of concave cross-section and a cylindrical inner passage of a diameter suitable for mounting on the outer rings of the bearings 32, 34. Ribs 38 protrude radially inwardly along the length of the cylindrical inner passage to the middle of the cylindrical inner passage.

[0055] The spindle 40 is a tubular component having a hollow shaft portion 50 with a cylindrical outer surface on which the inner rings of the bearings 32, 34 are supported. At a first end. The spindle 40 has a head 52 with a larger diameter than the shaft portion 50, with a curved inner surface that provides a smooth, diverging entrance to the interior of the shaft portion 50. The end portion 54 of the spindle 40 opposite the head 52 has a polygonal outer profile with a plurality of (in this embodiment, 10) flat faces. Internally, the spindle 40 has an internal thread starting from the multi-faceted end portion 54.

[0056] The shaft cap 42 has a hollow externally threaded shaft 58 and a head 60 centered on the shaft 58. The threads of the shaft 58 are adapted to interconnect with the threads of the spindle 40. The head 60 has a curved inner surface that provides a smooth, diverging entrance to the interior of the threaded shaft 58. The head 60 of the shaft cap 42 has a plurality of axially extending drive slots 66 spaced around its periphery.

[0057] The spacer 44 is shaped as a short cylinder with a radially projecting flange 62 proximate one of the ends of the spacer. A passage 64 extends axially through the spacer and is sized to provide a close sliding fit of the spacer 44 on the shaft portion 50 of the spindle 40 .

[0058] The first plate 10 has a through hole 16, the through hole 16 is centered at the sheave axis A. s The through hole 16 of the first plate 10 is centered and extends between the outer surface and the inner surface of the first plate 10. The peripheral shape of the through hole 16 of the first plate 10 is polygonal, and the size of the through hole of the first plate is such that the polygonal end portion 54 of the spindle 40 fits tightly therein. Therefore, the polygonal end portion 54 of the spindle 40 can be accommodated in the through hole 16 of the first plate 10, preventing the spindle from rotating about its axis. It should be understood that the specific shape of the through hole 16 of the end portion 54 of the first plate 10 of the spindle 40 is not limited to a polygon. What is required is that when the end portion 54 of the spindle 40 is accommodated in the through hole 16 of the first plate 10, the spindle is restricted from rotating. For example, they may alternatively have a flat cross-section, be square or have splines.

[0059] The second plate 12 has a through hole 18 centered on the sheave axis and extending between the outer and inner surfaces of the second plate 12. The through hole 18 of the second plate 12 is circular in cross section and has a stepped diameter so that a rib 70 of rectangular cross section radially protrudes into the through hole. The inner diameter of the through hole 18 of the second plate 12 in the region of the rib 70 is greater than the outer diameter of the portion of the spacer 44 near the flange 62 by an amount that enables the spacer to be inserted into the through hole 18 of the second plate 12 and rotated relative to the second plate 12 with minimal lateral movement. The rib 70 contacts the flange 62 to limit axial movement of the spacer within the through hole 18 of the second plate 12. The diameter of the through hole 18 of the second plate 12 between the rib 70 and the outer surface of the plate 12 is greater than the diameter of the head of the spindle 40 so that the head 52 fits tightly within the through hole.

[0060] The shaft assembly is established by passing the shaft portion 50 of the main shaft 40 through the outer surface of the second plate 12 into the through hole 18 of the second plate 12 until the head 52 of the main shaft 40 contacts the rib 70, thereby preventing further axial movement of the main shaft 40. The spacer 44 is then passed over the shaft portion 50 of the main shaft 40 so that the flange 62 is away from the head 52 of the main shaft 40 until the spacer contacts the inner surface of the head 52. The first of the bearings 34 is then slid onto the shaft portion 50 of the main shaft 40 until the inner race of the first bearing contacts the spacer 44. The annular spacer 72, the sheave 30 and the second bearing 32 are then arranged on the shaft portion, wherein the spacer 72 is aligned with the middle plane P. m The rib 38 of the sheave 30 is located at the middle plane P between the outer rings of the bearings 32 and 34. m The bearing and sheave are formed as a single unit, thereby avoiding the need for spacers.

[0061] Then, the polygonal end portion of the spindle 40 is inserted into the through hole 16 of the first plate 10, and the shaft cap 42 is arranged in place by screwing the shaft 58 of the shaft cap 42 into engagement with the internal thread of the shaft portion 50 of the spindle 40. The shaft cap 42 is tightened using a socket tool 78 having protruding teeth 80 that engage with the drive grooves 66 in the head 60 of the shaft cap 42 and a square recess 82 for receiving the socket drive tool. (See Fig.18 and Fig.19 ) Tighten the shaft cap 42 to connect the plates 10, 12, sheaves and shaft assembly together. The head 60 of the shaft cap 42 is received in a groove on the outer surface of the first plate 10.

[0062] The path that forces are transmitted through the components of the pulley block is important. Compressive forces are transmitted from the inner surface of the first plate 10 through the inner races of the bearings 32, 34 and the spacer shims 72 to the spacer 44 and then to the head 52 of the spindle. Tension forces are transmitted through the shaft 50 of the spindle 40 and the shaft 58 of the cap, and these forces are controlled by the degree to which the shaft cap is tightened using tool 78. The ribs 70 of the spacer 44 and the second plate 12 are sized so that the ribs 70 bridge, but do not clamp, between the flanges 62 of the spacer 44 and the head 52 of the spindle 40 - the spacer 44 carries all of the compressive forces. Instead, there is a small gap between the ribs 70 and the adjacent flanges 62 and head 52, which allows the second plate 12 to move about the sheave axis A on the spacer 44 and spindle 40. s Rotates with minimal lateral or axial movement.

[0063] A groove having a circular perimeter is formed in each of the plates 10, 12, the groove of the first plate being Fig.12 and Fig.19 The groove 84 is shown in FIG. 84. The diameter of the groove 84 is slightly larger than the outer diameter of the sheave 30. The axial end face of the sheave 30 is received in the groove to ensure that the sheave 30 does not contact the plates 10, 12 and to protect the periphery of the sheave from the influence of the rope passing through the pulley block, so that when the rope is inclined from the sheave axis A s The plate 10, 12 is shaped so that the material of the plate provides a smooth, curved lead-in to the sheave, which serves to minimize friction between the plate and the rope or other line within the pulley block.

[0064] It can be seen that the position of the polyhedral portion of the polygonal end portion 54 of the spindle 40 within the hole 16 of the first plate 10 prevents the spindle from rotating relative to the first plate 10 and relative to the spindle cap 42, thereby preventing accidental loosening of the spindle cap 42. The security of the spindle cap 42 is further enhanced by using a thread locking agent and providing a fixing mechanism for preventing the spindle cap 42 from loosening.

[0065] The securing mechanism comprises a wedge 90 which can be attached to a recess of the first plate 10 by means of a bolt 92 so that a portion of the wedge forcibly abuts against the head 60 of the shaft cap 42 , thereby preventing it from rotating relative to the first plate 10 and hence the spindle 40 .

[0066] exist Fig.11 In the illustrated embodiment, the wedge 90 has a flat portion through which two bolt holes pass, and the flat portion has an arcuate locking surface having a radius corresponding to the radius of the head 60 of the shaft cap 42. The locking surface tapers at an angle of approximately 10° from the normal to the flat portion. Figure 2 and Fig.11As can be seen in FIG. 1 , this maximizes the contact between the locking surface and the head 60 of the shaft cap 42. The wedge 90 also has a block protruding from its planar portion to space the planar portion from the surface of the first plate 10. Fig.11 As shown, in this arrangement, the clamping force F1 of the bolt 92 is determined by the force F applied to the head 60 of the shaft cap. r The reaction force F r There is a component orthogonal to the axis of the shaft assembly and a component parallel to the axis of the shaft assembly.

[0067] Fig.18 and Fig.19 A variation of the securing mechanism in an alternative embodiment is shown in . In this embodiment, the wedge 190 is tapered on the locking surface and the opposing surface so that when the wedge is tightened into the recessed portion of the plate, the wedge is pushed in to contact the head 60 of the shaft cap 42. In this embodiment, a single bolt 192 is used. In this embodiment, the wedge 190 will automatically center when the bolt 192 is tightened. In addition, the locking surface of the wedge 190 and the head 60 of the shaft cap 42 are serrated to provide a greater grip between the cap 60 and the wedge 190 - these serrations can also be used to Figures 1 to 17 In the embodiment, as a substitute or in addition to the drive slot 66.

[0068] The shaft assembly can be disassembled by reversing the above assembly process. It can then be reassembled using one or more replacement parts to replace parts that have suffered wear or damage (most typically the sheave 30 or bearings 32, 34, but it could be any other part) or to provide alternative functionality. Parts that have not worn beyond their useful life (e.g., plates 10, 12) can be reused.

[0069] In the region of the small boss portions 22, 22', a structure of cylindrical peripheral cross-section protrudes from each plate 10, 12, each protruding portion constituting a bollard structure 110, 112 formed integrally with the corresponding plate. The bollard structure 110, 112 is centered on a through hole at the small boss portion 22, 22' of each plate 10, 12. The through hole at the small boss portion 22, 22' is internally threaded.

[0070] Each bollard structure 110, 112 extends as a portion of the panels 10, 12, each having a first portion that is a cylindrical base 120 centered about the axis of the bollard and having a circular cross-sectional aperture 114, 116 extending through the first portion. The bollard structures 110, 112 are of complementary shapes so that when the pulley block is in the closed position, the bollard structures join together to form a bollard having a cylindrical cross-section extending between the panels 10, 12. While the bollard structures may be formed having many specific shapes, in this embodiment, the bollard structures have the additional property of resisting separation of the panels 10, 12 when lateral forces are applied to the panels 10, 12 when the pulley block is in the closed position. The shapes of the bollard structures will now be described.

[0071] Each bollard structure 110, 112 has an approximately C-shaped interlocking structure 122 extending from a cylindrical base 120. The interlocking structure 122 has an outer peripheral surface parallel to the midplane P. m The plane is C-shaped and the bollard axis A b The cylindrical base 120 is centered and parallel to the bollard axis A. b Thus, a groove 124 is formed between the interlocking structure 122 and the base 120. The surface S of each interlocking structure 122 defining the groove 124 is With the middle plane P m The surface S of the base 120 facing the interlocking structure 122 pi and the surface S of the interlocking structure 122 facing away from the base lp From the middle plane P m Offset common angle.

[0072] The bollard structures 110, 112 and associated structures are shaped and sized so that when the panels 10, 12 are relative to each other about the sheave axis A s When pivoting to bring the pulley block toward the closed position, each interlocking structure 122 enters the slot 124 of the other bollard structure, as best shown in FIG3. For each bollard structure 110, 112, the surface S of each base 120 facing the interlocking structure 122 is pi The surface S of the locking structure facing away from the base of another bollard structure lp The surfaces of the interlocking structure 122 defining the groove 124 come into contact with each other. Because these surfaces are relative to the middle plane P m The surface S of the interlocking structure 122 defining the groove 124 is inclined so as to produce a wedging effect, which causes the surface S of the interlocking structure 122 defining the groove 124 to is In addition, the inclined surface reduces the is and the middle plane P mThe need for precise alignment between the plates 10 and 12 is eliminated, as the wedging action tends to cause the plates to self-align. Thus, the two bollard structures form a unified cylindrical bollard extending between the plates 10 and 12.

[0073] A locking assembly is mounted on the second plate 12 and can be used to secure the plates 10, 12 to prevent movement relative to each other when the pulley block is in the closed position.

[0074] The locking assembly includes a cylindrical locking shaft 130. The locking shaft has a first end portion 132, the external threads of which are compatible with the threads of the through hole at the small boss portion 22 of the first plate 10. A hexagonal hole 134 is formed in the end of the locking shaft 130 radially inwardly from the threads of the first end portion 132 to enable the locking shaft 130 to be rotated using a suitable tool. In addition, the locking shaft has a second end portion 140 with external threads, and a threaded hole 142 is formed in the end of the locking shaft 130 radially inwardly from the threads of the second end portion 140. Between the end portions 132, 140, the locking shaft 130 is sized to fit tightly in the through hole of the small boss 22' of the second plate 12, and a peripheral groove is formed in the locking shaft 130, and an O-ring 144 (in the assembly mechanism) is located in the groove.

[0075] The locking assembly further includes an arbor 150. The arbor 150 has a central threaded hole that is threaded onto the second end portion 140 of the locking shaft 130 and is locked in place by a cap screw 152 that is screwed into the threaded hole 142 inside the second end portion 140 of the locking shaft 130. The arbor 150 has a central threaded hole that is threaded onto the second end portion 140 of the locking shaft 130 and is locked in place by a cap screw 152 that is screwed into the threaded hole 142 inside the second end portion 140 of the locking shaft 130. b The cylindrical peripheral wall is centered on the bollard, and the peripheral wall has a peripheral groove in which the O-ring 154 is located. Inside the peripheral wall, the shaft handle 150 has a peripheral groove that can be engaged by the user's fingers to surround the bollard axis A. b The structure of the rotating shaft handle.

[0076] In order to install the locking mechanism, before the shaft handle 150 is connected to the locking shaft 130, the second end portion 140 of the locking shaft 130 is passed through the through hole of the small boss 22' of the second plate 12 from the inner surface to the outer surface. Then, the shaft handle 150 is screwed onto the second end portion 140 of the locking shaft 130 and fixed by adding a cap screw 152. The O-ring 144 then passes over the free end of the locking shaft and is located in the peripheral groove. The locking shaft 130 can then slide axially in the through hole of the small boss 22', between the limit portion that cannot pass through the hole defined by the first end portion 132 of the locking shaft 130 and the shaft handle, and the shaft handle comes into contact with the second plate 12. When the locking shaft 130 is in this position (such as Fig.15 ), the pulley block is unlocked and the panels 10, 12 can be moved between the closed position and the open position. Fig.15 It can be seen that in this position of the locking shaft, the O-ring 144 is outside the second plate 12, and the O-ring is used to maintain the locking shaft 132 in that position, which prevents the locking shaft from colliding with the first plate 10 when the plates 10, 12 are pivoted between the closed position and the open position.

[0077] When the pulley block is closed and the holes in the small boss portions 22, 22' of the first and second plates 10, 12 are aligned, the locking shaft 130 can be pushed toward the first plate 10. Initially, the sliding movement of the locking shaft 130 is blocked by the O-ring 144, which must be compressed to pass through the through hole of the small boss portion 22' of the second plate 12. Once the locking shaft 130 is in contact with the first plate, the locking shaft can be rotated using the shaft handle 150 so that its first end portion 132 is pulled into the through hole of the small boss portion 22 of the first plate 10 by its thread until a locked configuration is achieved, as shown. Fig.14 In the locked configuration, the shaft handle 150 abuts the second plate 12, and the O-ring 154 in the peripheral wall of the shaft handle 150 contacts the cylindrical wall 28 of the small boss portion 22' of the second plate 12. The friction between the O-ring 154 and the cylindrical wall prevents the shaft handle 150 from rotating other than due to intentional manual action, thereby preventing accidental unlocking.

[0078] Fig.16 and Fig.17 An alternative configuration of an embodiment of the present invention in use is shown. In these figures, a fixed line L is shown passing over the bollard and through the shaft assembly. s , and shows the moving line L across the sheave 30 m (Line L extending through the shaft assembly s It can also move, but it is not connected to the line L that crosses the groove wheel 30. m will experience additional friction. Fig.17 As can be seen in the main shaft 40 and the curved surfaces in the shaft cap 42 provide a smooth path for the rope to enter and exit the shaft assembly. The presence of the wire passing over the bollard has the effect of pulling the bollard structures 110, 112 together towards the closed position. The effect of this is to ensure that the pulley block will not open even if the locking mechanism has failed or is not activated.

Claims

1. A pulley block, comprising: A first plate (10) and a second plate (12); A sheave (30) is disposed between the first plate (10) and the second plate (12), the sheave being adapted to rotate on bearings (32, 34) on a sheave shaft assembly which is rotatable along a sheave axis (A s ) extends between the first plate and the second plate, The first plate (10) and the second plate (12) are connected to the sheave shaft assembly so as to allow one plate to be moved relative to the other about the sheave axis (A s ) is rotatable between a closed position of the pulley block and an open position of the pulley block, and The sheave shaft assembly comprises: a main shaft (40) fixed to the first plate (10) and non-rotatable and freely rotatable relative to the second plate (12); and a shaft cap (42) clamping the main shaft (40) to the first plate (10), the shaft cap being detachably fixed to the main shaft, Features: Each of the shaft cap (42) and the spindle (40) includes a shaft portion (50) extending through respective through holes in the first plate (10) and the second plate (12), and each of the shaft cap (42) and the spindle (40) includes a head portion adjacent to surfaces of the first plate and the second plate adjacent to the through holes, respectively. The shaft assembly includes a spacer (44) that allows the head portion of the main shaft (40) to be parallel to the sheave axis (A) s ) direction and is spaced apart from the second plate (12), The shaft assembly is hollow to provide a shaft parallel to the sheave axis (A s ) direction through the pulley block, the cross-section of the end portion of the channel is convex to provide smooth entry and exit for the wire, belt or other load-bearing components entering and leaving the channel.

2. The pulley assembly according to claim 1, wherein: The shaft cap (42) is threadably engaged with the main shaft (40).

3. The pulley block according to claim 1 or 2, further comprising a fixing mechanism, wherein the fixing mechanism prevents the shaft cap from rotating relative to the first plate.

4. The pulley assembly according to claim 3, wherein: The fixing mechanism is removable so that the shaft cap (42) can be separated from the main shaft (40), thereby enabling the shaft assembly to be disassembled.

5. The pulley assembly according to claim 4, wherein: The securing mechanism includes a wedge (90) that can be attached to the first plate (10) so that a portion of the wedge forcibly abuts against a head portion of the shaft cap (42), thereby preventing the shaft cap from rotating relative to the first plate (10).

6. The pulley assembly according to claim 5, wherein: The wedge (90) is attachable within a recess in the first plate (10).

7. The pulley assembly according to claim 6, wherein: The wedge (90) has a tapered locking surface that contacts the head portion of the shaft cap (42).

8. The pulley block according to claim 1 or 2, wherein: The spindle (40) has an end portion (54) opposite the head portion, the end portion being received in a through hole in the first plate (10) and thereby restricted from rotating relative to the first plate.

9. The pulley assembly according to claim 8, wherein: The end portion (54) of the main shaft (40) is polygonal in shape.

10. The pulley block according to claim 1 or 2, wherein: Each of the first plate (10) and the second plate (12) has a corresponding bollard structure (110, 112) at a position away from the axis of the sheave, and the bollard structures are arranged so that when the first plate (10) and the second plate (12) are in the closed position, the corresponding bollard structures (110, 112) are in contact with or in close proximity to each other to form a bollard extending between the first plate (10) and the second plate (12), and when the first plate and the second plate are in the open position, the corresponding bollard structures are spaced apart.

11. The pulley assembly according to claim 10, wherein: A respective hole (114, 116) extends through each of the bollard structures (110, 112) and is oriented on the bollard axis (A) when the pulley block is in the closed position. b ) are aligned with each other, whereby the pulley block can be fixed in the closed position by a locking mechanism, which operates to insert a locking member into the hole to keep the holes aligned with each other.

12. The pulley assembly according to claim 11, wherein: The bollard structures (110, 112) are shaped such that in the closed position, a portion (122) of a bollard structure is parallel to the bollard axis (A) b ) in the direction of the component of the bollard structure, overlapping and contacting a portion of another bollard structure, the overlapping portions of the bollard structures having surfaces in contact with each other that are orthogonal to the bollard axis.

13. The pulley assembly according to claim 10, wherein: In the closed position, the bollard structures (110, 112) together form a bollard that is convex in cross-section in a direction facing the sheave (30).

14. The pulley block of claim 1 or 2 having two or more sheaves disposed between the first plate and the second plate.

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