Patent Description:
A Tyrolean traverse is performed by connecting a main line between two remote locations across an expanse and placing a carriage on the main line. The carriage has a plurality of sheaves or other low-friction devices that allow it to travel along the main line. Control lines are connected to the carriage to control its movement along the main line. The carriage also has connection points to which a load can be connected. As the control lines are used to move the carriage along the main line, it is possible to move a load connected to the carriage between the remote locations. This arrangement has a variety of applications, including movement of inanimate objects, such as timber from a cut-down tree, or transport of people, either to cross a void, or to rescue an incapacitated person.

<CIT> and <CIT> disclose a trolley for performing a Tyrolean traverse which is effective and useful. An aim of this invention is to provide a trolley that is easier to use, lighter than existing products and all components are replaceable. A trolley embodying this invention may be simpler or less expensive to manufacture without any reduction in strength and durability.

<CIT>, <CIT> and <CIT> disclose zip line apparatus for carrying a person or an object using gravity along an extended cable line suspended between two trees or towers.

To this end, from a first aspect, the invention provides a trolley for lifting and/or moving a load on one or more lines comprising:.

The retention fasteners and sheave axles serve to connect the plates together in a strong and solid manner. For installation, free access can be obtained to allow introduction of lines into the trolley by removal of the retention fasteners.

Typical embodiments include three or more (e.g., four) sheave assemblies.

Each sheave cartridge preferably includes a sheave boss that surrounds the sheave axle shaft, and which is clamped between the plates by force applied by the retention fastener. The retention fastener and sheave axle are therefore in tension, which the sheave boss provides structure in compression for reacting the tension in the sheave axle. The boss is generally fixed against rotation with respect to the plates, and preferably also with respect to an inner race of the bearing, while an outer race of the bearing is fixed for rotation with the pulley wheel.

Each sheave axle is preferably secured to the first plate by a releasable fixation fastener. When secured to the first plate, part of the shaft of the sheave axle typically extends through a hole in the first plate and projects from an inner surface of the first plate, and a head of the sheave axle is typically in contact with an outer surface of the first plate. In the latter case, the head is shaped and/or dimensioned such that it cannot pass through the hole in the first plate. When secured to the first plate, axial and rotational movement of the sheave axle with respect to the plate is prevented. Note that removal of the sheave axles from the first plate is not required to gain access to the sheaves.

A trolley assembly embodying the invention may comprise two (or more) interconnected trolleys as defined above, the plates of the trolleys being parallel to one another.

From a second aspect, this invention provides an installation for lifting and/or moving a load that includes a trolley or trolley assembly embodying the first aspect of the invention, a main line that extends between two fixed anchorages, and which, in use, passes between the plates of the trolley, whereby the main line makes contact with one or more sheave or sheave component of the trolley whereby the trolley can be suspended from and travel along the main line.

A typical installation further includes a control line that is connected to the trolley whereby the trolley can be drawn along the main line.

A typical installation further includes a lifting line that passes between the plates of the trolley and over two or more sheaves or sheave components of the trolley, the lifting line carrying, between the sheaves or sheave components, a device such as a pulley for connection with a load.

An alternative installation includes a second lifting line upon which a pulley assembly is carried, the pulley assembly being connected to support the trolley.

One or more fixed lines may be connected to the trolley. These can provide additional lifting capacity, for example serving as a climbing line and a backup line to enable a person to descend and ascend with respect to the trolley, for example to accompany a person being rescued.

From a third aspect, this invention provides a method of installing an installation according to the second aspect of the invention comprising:.

Typically, prior to step c. , part of a lifting line may be passed between the plates of the trolley.

Embodiments of the invention will now be described in detail, by way of example, with reference to the accompanying drawings, in which:.

With reference to the drawings, a trolley for use in performing a Tyrolean traverse comprises first and second side plates <NUM>, <NUM> of similar peripheral size and shape. The side plates <NUM>, <NUM> are formed from a suitable load-bearing material such as an alloy, stainless steel or composite material. In an orientation in which the trolley will typically be used, the plates are an approximate inverted U-shape. The plates are symmetrical about a median axis A (shown in <FIG>) with first and second legs to opposite sides of the axis A and a recess defined between the legs. Various holes are formed in the plates, each hole, in the assembled trolley, being in alignment with a corresponding hole in the other plate.

The trolley further includes four sheave assemblies, one of which is shown in detail in <FIG>. The sheave assemblies are disposed at the vertices of a rectangle that is symmetrical about the median axis forming an upper pair of sheave assemblies and a lower pair of sheave assemblies. One of the upper sheave assemblies has been omitted from <FIG> to illustrate features that would otherwise be hidden.

Each sheave assembly includes a sheave cartridge <NUM> that comprises a pulley wheel <NUM> carried on a rolling element bearing <NUM>. An outer race of the bearing <NUM> rotates with the pulley wheel <NUM> and an inner race of the bearing <NUM> is carried on and a sheave boss <NUM>. The sheave boss <NUM> has a central cylindrical bore centred on the axis of rotation of the pulley wheel <NUM>.

Each sheave assembly further includes a sheave axle <NUM>. The sheave axle <NUM> has a cylindrical shaft <NUM> at one end of which is a head <NUM>. The shaft <NUM> is dimensioned to be a close fit within the bore of the sheave boss <NUM>. The head <NUM> extends radially from the shaft <NUM> and has a projecting region that has a part-circular notch <NUM> formed in a radially-outward-facing surface. A coaxial tapped bore <NUM> is formed into the shaft <NUM> from its end opposite that of the head <NUM>. A further coaxial blind hole <NUM> may be formed through the head <NUM>.

Each sheave assembly includes a fixation bolt <NUM> and a retention bolt <NUM>, the purpose of which will be described below.

Assembly of the trolley proceeds in stages as will now be described.

During the stage of assembly described in the last-preceding paragraph, movement of the sheave axles <NUM> is prevented by the fixation bolts. This allows this stage of assembly to be performed using a single tool to tighten the retention bolts <NUM>: there is no need to use a tool on the axle <NUM> or the fixation bolt <NUM>.

The head <NUM> of each retention bolt has a circumferential groove within which an O-ring <NUM> is located. The O-ring <NUM> serves two purposes: when the retention bolt <NUM> is tight, it is compressed between the head <NUM> and the counterbored cavity to resist rotation of the retention bolt <NUM> against unintended loosening; and it provides a visible indication of the retention bolt <NUM>' being insufficiently tightened, as shown at the left-hand side of <FIG>, by remaining visible from the exterior of the plate <NUM>. To enhance performance of the latter purpose, the O-ring <NUM> is preferably brightly coloured - for example, coloured red.

In the event that a retention bolt <NUM> is omitted or becomes loose, the axle <NUM> will not be lost, because the fixation bolt <NUM> will prevent its removal from the first plate. The retention bolts <NUM> of the other sheave assemblies maintain the overall structural integrity of the trolley, and while it is believed that the strength of the trolley would not be significantly affected if one of the retention bolts were not tightened correctly or were missing entirely, this is an undesirable situation that is to be avoided if possible.

Each plate <NUM>, <NUM> includes a plurality of additional pairs of circular mounting holes <NUM>. Each pair of mounting holes <NUM> can receive a removable pin <NUM>, which locks into place in the holes until it is released by a user-operated trigger.

When not in use, each retention bolt can be inserted into a blind hole e.g. <NUM> in the head <NUM> of the sheave axle <NUM>.

Assembly of a complete installation for moving items using the trolley describe above will now be described.

In addition to the trolley, the installation comprises several lines formed from ropes or cables. These are:.

A typical sequence of assembly is as follows:.

Slackening or loosening the lifting line <NUM> causes a load L attached to the pulley block <NUM> to be lowered or raised with respect to the trolley. As shown in <FIG>, in a raised position, the pulley block <NUM> is received within the recess between the legs of the trolley. When the pulley block <NUM> is in this position, the lifting line passes <NUM> through the trolley along an approximately straight path, which minimises friction arising from movement of the trolley.

In installations where the main line <NUM> is sloping, one control line <NUM> can be used to pull the trolley in an upward direction on the main line <NUM> or released in a controlled manner to cause the trolley to move in a downward direction along the main line <NUM> under the action of gravity. Where there is no overall slope, two control lines <NUM>, <NUM>' may be provided to pull the trolley in opposite directions along the main line <NUM>.

The arrangement of <FIG> uses the same trolley described above. Series redundancy is created by providing an additional main line <NUM>. An additional pulley assembly <NUM> is carried on the additional main line <NUM> and connected to the trolley using a pin <NUM> inserted into a pair of mounting holes <NUM> towards the top of the plates <NUM>, <NUM>. In that way, should the main line <NUM> fail, the additional main line serves as a backup to prevent loss of a load being carried. This arrangement can be used with a single control line <NUM> or two control lines <NUM>, <NUM>' as needed.

Also shown in this embodiment are additional lines <NUM> that can be used to carry a load. These are fixed lines that are each secured to the trolley using a pin <NUM> inserted into a pair of mounting holes <NUM> towards the bottom of the plates <NUM>, <NUM>. A typical use for these fixed lines <NUM> would be to allow a person to accompany a load, such as an injured person, being lifted on the pulley block <NUM>. In such an application, one of the fixed lines <NUM> would be used as a climbing line upon which a climber could move using an ascender, and the other fixed line <NUM> would be used as a back-up line to protect the climber against failure of the climbing line and associated apparatus.

A trolley as described above could be paired, as shown in <FIG> and <FIG>, with another identical trolley to create a system which has theoretically twice the strength and lifting capacity as that described above, but most importantly for some users gives redundancy in the system and a backup device through a parallel redundancy system. Using such a trolley, each line and piece of equipment being part of an installation can be duplicated to provide redundancy and therefore protect against failure of multiple components in the installation. Two trolleys are joined together using long bolts <NUM> and spacers through the first and second plates <NUM>, <NUM>.

While stage B of the assembly sequence described above is being performed, the sheave cartridges <NUM> have been slid onto the shafts <NUM> of the sheave axles <NUM>, but they are not retained there, which means that they could slide off and potentially become lost. To minimise the risk of this happening, in a modification of the above-described embodiment shown in <FIG>, a circumferential groove is formed on the shafts <NUM> of the sheave axles <NUM> and an O-ring <NUM> is retained in the groove. The sheave boss <NUM> is gripped by the O-ring <NUM> with sufficient force that it will not fall off the shaft <NUM> accidentally under the weight of the sheave assembly, but such that it can be removed using light manual effort when required.

A further alternative configuration of the sheave assembly is shown in <FIG>. In this arrangement, there is no sheave boss <NUM>, and the inner race of the bearing <NUM> is carried directly upon the shaft <NUM> of the sheave axle <NUM>. As compared with the arrangement described above, the shaft <NUM> of the sheave axle <NUM> is of larger diameter so that the size of the bearing <NUM> can remain unchanged. Axial location of the bearing <NUM> on the axle <NUM> is provided by annular abutments <NUM>, <NUM> that project from the first and second plates <NUM>, <NUM>. The abutments <NUM>, <NUM> closely surround the shaft <NUM> of the sheave axle <NUM>, and make contact with opposite side faces of the inner race of the bearing <NUM> to prevent it moving axially along the shaft <NUM>, and thereby preventing axial movement of the pulley wheel <NUM>.

Claim 1:
A trolley for lifting and/or moving a load on one or more lines comprising:
a. a first side plate (<NUM>) and a second side plate (<NUM>) and
b. three or more sheave assemblies;
in which each sheave assembly includes
c. a sheave axle (<NUM>) that includes an axle shaft (<NUM>) which projects from the first plate (<NUM>) and passes into a hole (<NUM>) in the second plate (<NUM>), a sheave cartridge (<NUM>) being carried on the axle shaft between the plates, wherein each sheave cartridge includes:
i. a pulley wheel (<NUM>) that can rotate on a bearing (<NUM>) around an axis of the axle shaft (<NUM>); and
ii. a removable retention fastener (<NUM>) that extends through the hole (<NUM>) in the second plate (<NUM>) to engage with the axle shaft movably secure the second plate to the first plate through the axle shaft;
d. wherein the axes of the axle shafts (<NUM>) are parallel to one another.