GB2608163A

GB2608163A - Improved crane

Info

Publication number: GB2608163A
Application number: GB2109098.0A
Authority: GB
Inventors: Lee Crowder Jeff
Original assignee: CDR SYSTEMS Ltd
Current assignee: CDR SYSTEMS Ltd
Priority date: 2021-06-24
Filing date: 2021-06-24
Publication date: 2022-12-28
Also published as: GB202109098D0

Abstract

A crane 10 for use in raising windows into place in a window opening in a building has a mast 12 with a boom 14 pivotally mounted thereon, a winch 18 mounted on the mast 12, a distal pulley 20 mounted on the boom 14 towards a distal end, an intermediate pulley 22 mounted on the boom between the distal pulley 20 and a proximal end of the boom 14, a mast pulley 26 mounted on the mast 12 towards the top and a cable 28 which runs from the winch 18 to the mast pulley 26 to the intermediate pulley 22 and on to the distal pulley 20 for subsequent engagement with a load L. The intermediate pulley 22 is mounted on the boom 14 with a mounting adapted to be moveable along the boom 14. The intermediate pulley 22 may be mounted on a bearing which can move within a slot 24 formed in the boom 14 and a spring may urge the bearing towards the proximal end of the boom 14.

Description

Improved Crane

Field of the invention

The present inventive concept relates to cranes, especially those used for raising and lowering window elements such as glazing units for repair or replacement thereof.

Window elements are heavy and vulnerable to damage; the raising and lowering thereof is a specialised area of endeavour.

Background to the invention

International patent application with publication no. W02006/000808 of Jeffrey Lee Crowder discloses a crane for use in raising window elements into place in a window opening in a building. An embodiment disclosed in that earlier publication, shown and described in respect of Figure 6 is especially relevant.

The disclosure of Crowder -who is also the inventor of the present inventive concept -is considered to be the closest prior art relating to the present application. -2 -

The present inventive concept seeks to provide improvements over the earlier arrangement, enabling a crane to lift larger weights.

Summary of invention

The present inventive concept provides a crane for use in raising windows into place in a window opening in a building, the crane having a mast with a boom pivotally mounted thereon, the crane further having a winch mounted on the mast, a distal pulley mounted on the boom towards a distal end thereof, an intermediate pulley mounted on the boom between the distal pulley and a proximal end of the boom, a mast pulley mounted on the mast towards the top thereof, and a cable which runs from the winch to the mast pulley to the intermediate pulley to the distal pulley for subsequent engagement with a load, characterised in that the intermediate pulley is mounted on the boom with a mounting adapted to be moveable along the boom.

The skilled reader will understand that whilst the term cable is used in this description, functionally equivalent elements such as a rope or the like may be used without departing from the inventive concept The ability for the mounting of the intermediate pulley to be moved along the boom is advantageous in that slippage of the cable is reduced and the cranking load of the winch can be lessened, enabling a larger maximum weight to be lifted. For example, the crane of the earlier Crowder disclosure can handle a maximum load of around 100 kg. The present arrangement provides for an increase in maximum load to around 150 kg.

With the crane of the earlier Crowder disclosure -with a fixed position of the intermediate pulley -it was found that the position of the intermediate pulley affected the performance of the crane. For example if the intermediate pulley were positioned too close to the distal pulley, slippage would occur when lifting a load causing the boom to suddenly move upwards and hit the mast in an uncontrolled manner causing the load to be lowered rapidly whilst taking up slack in the cable. Clearly, this is not ideal when lifting heavy loads as it could cause a shock loading in the crane support system, within the window opening. -3 -

Alternatively, if the intermediate pulley were positioned further away from the distal pulley nearer to the mast, slippage would also occur but on the lowering process. The boom would stay in a position approaching the vertical and, instead of deploying the winch cable outwards before Lowering, the boom would not move and the winch cable would be paid out downwards, vertically, causing anything attached to it such as Lifting equipment being lowered to the ground to interfere with the window sill, instead of -as preferred -being Lowered clear of the building with a fully deployed boom. Whilst this was slightly safer than the aforementioned situation, it caused an inconvenience when lowering both Light and heavy loads. Furthermore when the intermediate pulley is in such a position, the leverage compared with when the intermediate pulley is closer to the distal pully gives rise to an increased cranking Load on the winch for a given Load.

An increase in Load exaggerates any imbalances. Furthermore, the ideal position for the intermediate pulley varies with load.

Provision of the intermediate pulley being mounted on the boom with a mounting adapted to be moveable along the boom thus gives rise to several synergistic advantages.

In addition, to accommodate a significant increase in maximum load, the mast and boom should be longer, and the cable stronger by being thicker. Thus the geometry suitable for a crane capable of Lifting and lowering heavier loads must be altered.

Preferably, the mounting comprises a bearing on which the intermediate pulley is rotatable. Preferably, the mounting comprises a spring engaged with the said bearing the spring being arranged to urge the bearing towards the proximal end of the boom. One or more parts of the said bearing may be captured in a slot formed in the boom.

The provision of a spring enables the intermediate pulley to move along an axis of the boom away from the proximal end of the boom under a force from the load transferred via the cable. In other words, the intermediate pulley can reposition according to the Load being raised or lowered, which improves the performance of the crane for the reasons set out above. Use of low friction materials such as ball bearings in the pulleys to minimise the effort required to lift or lower the increased load within accepted manual operational parameters, benefits from an intermediate pulley as described that has a movable pivot point, such that when under high loading it moves under its own -4 -force towards the end of the boom, or if subject only to a light Loading remains in the default position closer towards the mast pivot point.

The skilled reader will understand that whilst the term spring is used in this description, functionally equivalent elements may be used without departing from the inventive concept.

Improved control of the boom and the lifted load is advantageous when lifting or Lowering heavy Loads. Thus providing an adjustable intermediate pulley position brings significant improvements in the performance of a crane.

The present inventive concept provides such positioning control by spring pressure and automatically adjusts to suit the imposed load. The spring may be arranged as an external spring arrangement or an internal spring arrangement.

The crane may further comprise a means adapted to adjust the spring force. Said means may comprise an adjustment wheel, which can be rotated by hand. This provides a micro adjustment facility to suit operational conditions.

The skilled reader will envisage other combinations of springs, levers, fixings and devices that would allow for the correct positioning of the intermediate pulley within a desired movement path, which would fall within the scope of the present inventive concept.

Preferably, the boom comprises a pair of elongate members which are arranged mostly in parallel with one another, the elongate members linked together to form a frame.

Preferably each elongate member has a slot formed therein, adapted to capture the said bearing. Whilst the elongate members are said to be arranged mostly in parallel with one another, the distance between then may vary. For example, the elongate members may be closer together at a distal end of the boom than at the proximal end, i.e. in the region which engages the mast. When the boom comprises a pair of elongate members, the bearing and the spring may be arranged between the elongate members.

The boom may further comprise a blocking pin arranged between the distal pulley and the distal end of the boom. Such a blocking pin can prevent a Load attachment from being drawn past the distal pulley during raising of a load. A stopper ball may be provided attached to the cable, arranged between the blocking pin and the said load attachment -5 -Thus when the load is attached to the lifting rope and hoisted up, a stopper ball attached to the lifting rope positioned above the attachment eye, then bLocks out at the boom end by contact with a boom end blocking pin, causing the boom to be raised by the continued winding action of the winch.

A preferred arrangement has a bearing comprising an axial bolt arranged within slots in each of a pair of elongate members, with the bolt also passing through the intermediate pulley so that the pulley can rotate around the bolt, the bearing further comprising a bracket mounted to the axial bolt and shaped so as to not interfere with rotation of the pulley, the bracket comprising an engagement means adapted to engage one end of a threaded spring bolt. Preferably the other end of the spring engages with a hand wheel adapted to screw axialLy around the thread of the spring boft so as to increase or reduce the axial length of the spring. This arrangement could be described as an internal spring arrangement In use, the resting length of the spring can be varied so that the weight of the Load required to move the intermediate pulley within the slot can be varied. This provides a user with the ability to make fine adjustments to the crane.

Another preferred arrangement has a bearing comprising an axiaL bolt arranged within slots in each of a pair of elongate members, with the bolt also passing through the intermediate pulley so that the pulley can rotate around the bolt. A pair of springs are arranged to be attached to the bearing at approximately either end of the bearing, with the said elongate members being between the springs. This arrangement couLd be described as an external spring arrangement. Ends of the springs not attached to the bearing are attached to the respective elongate member.

Preferably, the said slots in the elongate members have its or their end closest to the proximal end of the boom approximateLy one third of the Length of the boom from the proximal end of the boom. In other words, that proximal end of the slots is approximately twice as far away from the distal end of the boom than from the proximal end of the boom.

The said slots may be approximately 20 to 40 mm long. In other words, the intermediate pulley may move up to between 20 to 50 mm along the boom under load.

Preferably, the said slots are approximately 30 mm long. -6 -

The winch may be adapted to be wound or unwound by an external source of mechanical torque. The winch may thus comprise a driving surface adapted to engage with a screwdriver tip. Such a driving surface may comprise one or more slots, grooves, recesses or the like. The source of mechanical torque may be a suitable power tool, for example an electric drill or electric screwdriver.

The winch may comprise a generator of mechanical torque. Such a generator of mechanical torque may be a motor or the like.

The crane may further comprise a trip device to stop an electrical supply to such a motor. For example, the trip device may comprise a trip switch or the like adapted to operate as the boom reaches the mast, or in the event of overloading or a blockage. Alternatively or in addition the crane may further comprise a mechanical means adapted to prevent over-driving of the winch such as a torque set ratchet to stop drive to the winch.

Detailed description of the invention

Elements of exemplary embodiment of the present inventive concept will now be described with reference to the accompanying drawings, in which: Figure 1 shows a partial_ cross-section of an embodiment of the crane of the inventive concept; Figure 2 shows a partial cross-section of the same embodiment of the crane shown in Figure 1, with a different load; Figure 3 shows a simplified representation of the same embodiment, with the intermediate pulley shown in two possible states; Figure 4 shows an expanded view of parts of the same embodiment; Figure 5 shows an expanded view of parts of the same embodiment; Figure 6 shows a partial cross-section of the same embodiment at one lifting stage; 7 -Figure 7 shows a partial cross-section of the same embodiment at a different lifting stage from that shown in Figure 6; Figures 8A and 8B show a possible external spring arrangement for use with the present inventive concept; and Figures 9A and 9B show a possible internal spring arrangement for use with the present inventive concept.

The skilled reader will appreciate that not all of the elements are labelled and referred to with respect to each drawing, to aid clarity and understanding.

Turning to Figure 1, a crane 10 is shown having a mast 12 and a boom 14. The mast 12 is arranged substantially vertically in use, and the boom 14 is mounted on the mast 12 by way of a pivoted connection 16. The boom 14 can be said to have a proximal end near the pivoted connection 16 and a distal end away from the said proximal end. The crane 10 has a winch 18 which is also mounted on the mast 12.

Towards the distal end of the boom 14 is arranged a distal pulley 20, and between the distal pulley 20 and the proximal end of the boom is arranged an intermediate pulley 22. The intermediate pulley 22 is mounted on a bearing (not shown), and the bearing can move within a slot 24 which is formed in the boom 14. The bearing is engaged with a spring (not shown). Towards the upper end of the mast 12 is a mast pulley 26. A cable 28 runs from the winch 18 to the mast pulley 26 to the intermediate pulley 22 then to the distal pulley 22 before engaging with a load [(not part of the embodiment as such).

Between the distal pulley and the distal end of the boom is a blocking pin 46.

An optional support rope 30 is also shown in this embodiment, fixed at each end to an upper part of the mast 12 and towards the distal end of the boom 14; the rope 30 prevents the distal end of the boom 14 from extending further from the mast 12 than the length of the rope, so that the boom 14 is prevented from dropping under the weight of the load [than desirable. Preferred embodiments also include a catch for storing the crane 10 if the boom 14 is brought close to upright towards the mast 12; the catch is not shown in this drawing to aid clarity. -8 -

In use, the Load L can be raised and lowered by rotation of the winch 18 to wind in or pay out the cable 28. If the load L is heavy, then the weight can overcome the force of the spring which engages the bearing to move the bearing within the slot 24. This movement provides the advantages set out previously. If the Load L is not heavy, then the bearing does not move within the siot 24, as in this example.

Figure 2 shows the same embodiment of the crane 10; for clarity several of the Labels have been omitted. In this example the Load L' is heavier than the Load L of Figure 1. As can be seen in Figure 2, the Load L' has overcome the spring force so that the bearing has moved within the slot 24 towards the distai end of the boom 14, and thus the intermediate pulley 22 has moved towards the distal end of the boom 14.

Figure 3 shows a simplified representation of the same embodiment of Figures 1 and 2; again for clarity several of the Labels have been omitted. The crane 10 is shown with the intermediate pulley 22 in two possible positions labelled as BH and BL. When a heavy Load is in place, the Load may overcome the spring force so that the bearing moves within the slot 24 towards the distal end of the boom 14, so that the intermediate pulley 22 moves to position BH. When a Lighter load is in pLace, the Load does not overcome the spring force, so the bearing is not displaced within the slot 24, so that the intermediate pulley 22 remains in position BL Figures 4 and 5 show shows an expanded view of parts of the same embodiment; several elements are now shown and again for clarity several of the Labels have been omitted.

Figure 4 shows the position of the intermediate pulley 22 within slot 24 when a Lighter Load L is in pLace. When a lighter load L is in pLace, the load does not overcome the spring force so the bearing remains towards the proximal end of the boom 14-corresponding to state BL in Figure 3. In Figure 5 a heavier load L' is in place, which has overcome the spring force so that the bearing has moved within slot 24 towards the distal and of the boom 14-corresponding to state BH in Figure 3.

Figure 6 shows the arrangement of Figures 2 and 5, with a heavier load ['in place, with the crane 10 near the end of a lifting phase.

Figure 7 shows the same embodiment as described above, with a boom latch 32 visible.

The boom Latch 32 is pivotably attached to the mast 12 and releasably engageable with the distal end of the boom 14. Thus, when the boom 14 is brought close to upright -9 -towards the mast 12, the latch 32 can be engaged so as to prevent further relative movement between the boom 14 and the mast 12. This is especially advantageous near or at the end of a lifting phase to prevent unwanted lowering of a load.

Figures 8A and 8B show an external spring arrangement for use with the present inventive concept. Figure 8A shows a pair of springs 34 arranged externally relative to elongate elements of the boom 14. Springs 34 are in a relatively neutral state when a Lighter load is in place as in Figure 8A. The springs 34 are fixed at a first end 36 relative to the boom 14 and are attached at their other end to a bearing 38 which is free to move in slots (not shown) formed in elongate elements of the boom 14. In Figure 8B the springs 34 have been elongated due to a heavier Load being in place. The fixed end 36 has not moved, but the springs have elongated and provided for bearing 38 to move in the said slots, so bearing 38 has moved relative to the boom 14 to move the intermediate pulley 22. Part of the cable 28 is shown in both drawings.

Figures 9A and 9B shows an internal spring arrangement for use with the present inventive concept. Figure 9A shows a spring 34' arranged between elongate elements of the boom 14. Within the spring 34' is a threaded spring bolt 40 which has at one end a hand wheel 44 fixed relative to the spring 34' and the other end captured within a bracket 42. The bracket 42 engages the bearing 38 and allows the rotation of the bearing 38 and thus the intermediate pulley 22. Rotation of the hand wheel 44 rotates the spring bolt 40 to add or reduce tension in the spring 34', which means that a user is able to adjust the load at which the bearing 38 may move within the slots. In Figure 9B the hand wheel 44 has increased the tension in the spring 34' by increasing the resting Length of the spring 34'. The result is that the intermediate pulley 22 moves within the slots only when a Larger load is in place.

In an exemplary embodiment such as the one described above, the crane has a winch which may be manually or electrically operated mounted on the vertical support mast, around which the lifting cable is wound. The cable extending from the winch passes over the pulley at the top of the mast, then down to and under an intermediate pulley mounted on the boom arms, between the mast pivot point and the distal end of the boom. The cable then passes over a pulley at the end of the boom, past a blocking pin to a load attachment point -10 -When the Load is attached to the cable and hoisted up, a stopper ball attached to the Lifting rope positioned above the attachment point, then blocks out at the distal end of the boom by contact with a blocking pin, causing the boom to be raised by the continued winding action of the winch.

Further winding of the winch draws the boom towards the mast so that the window, glass or material being raised can be located in its final securing position without removing the crane from the window opening.

The crane has a latch to hold the boom arms (elongate sections of the boom) in a vertical position without further deployment, so that small Lifting or Lowering adjustments to the lifted load height may be carried out by winding the winch handle, adjusting the position of the load correctly in the window opening, prior to fixing.

The latch also serves to hold the crane with its mast and boom arms in a dosed and safe position to aid in carrying and storage.

When an attached load is to be lowered the latch is released and winding of the winch causes the boom arm to be automatically deployed outwards before the cable and its attached stopper ball and attached Load is Lowered.

The boom recovery and deployment operation is an automatic process created by frictional resistance in the boom pivot points, and pulley bearings, and governed by the pulley's relative positions to each other, further enhanced by the intermediate pulley arrangement The boom deployment position is Limited by a support rope, positioned between the mast upper point and the boom's end point, establishing a boom 'reach' position before any lowering of the lifted load commences to avoid any obstacles in the line of lift

Claims

Claims 1. A crane for use in raising windows into place in a window opening in a building, the crane having a mast with a boom pivotally mounted thereon, the crane further having a winch mounted on the mast, a distal pulley mounted on the boom towards a distal end thereof, an intermediate pulley mounted on the boom between the distal pulley and a proximal end of the boom, a mast pulley mounted on the mast towards the top thereof, and a cable which runs from the winch to the mast pulley to the intermediate pulley to the distal pulley for subsequent engagement with a load, characterised in that the intermediate pulley is mounted on the boom with a mounting adapted to be moveable along the boom.
2. A crane according to claim 1, wherein the mounting comprises a bearing on which the intermediate pulley is rotatable.
3. A crane according to claim 1 or claim 2, wherein the mounting comprises a spring engaged with the said bearing the spring being arranged to urge the bearing towards the proximal end of the boom.
4. A crane according to claim 2 or claim 3, wherein one or more parts of the said bearing may be captured in a slot formed in the boom.
5. A crane according to claim 3, further comprising means adapted to adjust a spring force of the said spring.
6. A crane according to claim 5, wherein the means adapted to adjust the spring force comprises an adjustment wheel, which can be rotated by hand.
7. A crane according to any preceding claim, wherein the boom comprises a pair of elongate members which are arranged mostly in parallel with one another, the elongate members linked together to form a frame.
8. A crane according to claim 7, wherein each elongate member has a slot formed therein, adapted to capture the said bearing.
9. A crane according to claim 7 or claim 8, wherein the crane has a bearing comprising an axial bolt arranged within slots in each of a pair of elongate members, with the bolt also passing through the intermediate pulley so that the pulley can rotate around the bolt, the bearing further comprising a bracket mounted to the axial bolt and shaped so as to not interfere with rotation of the pulley, the bracket comprising an engagement means adapted to engage one end of a threaded spring bolt.
10. A crane according to claim 9, wherein the other end of the spring engages with a hand wheel adapted to screw axially around the thread of the spring bolt so as to increase or reduce the axial length of the spring.
11. A crane according to any of claims 8 to 10, wherein the said slots in the elongate members have its or their end closest to the proximal end of the boom approximately one third of the length of the boom from the proximal end of the boom.
12. A crane according to any preceding claim, wherein the winch is adapted to be wound or unwound by an external source of mechanical torque.
13. A crane according to any preceding claim, wherein the winch comprises a generator of mechanical torque.