WO2015110781A1 - Improvements in and relating to zipwire trolleys - Google Patents

Abstract

A zipwire trolley (1) comprising or including a frame (2) of generally inverted "U"- shape and associated at least one zipwire engageable roller (4), means (5) on the frame below the at least one roller for receiving a load to be carried via a karabiner or sling, and a moveable gate (8) for releasably locking the trolley to a zipwire, characterised in that the gate (8) is generally planar and includes at least one generally planar lug or lug-shaped locking formation (10) co-operable with correspondingly shaped lug(s) or locking formation(s) (11) on or in the frame whereby when the gate is closed the or each lug co-operates with the or each locking formation(s) to provide mechanical support for the frame and gate when the trolley is mounted on the zipwire and under tensile load.

Description

Improvements in and relating to zipwire trolleys

This invention relates to zipwire trolleys, also known as zipwire pulleys, for traversing wire cable stretched between anchor points, such as anchor points fixed to climbing towers within a wooded theme park offering adventure activities at height. There are typically several zipwires to traverse at each such facility separated by e.g rope walkways such that when one zipwire has been successfully traversed it is necessary to unhook the zipwire trolley from the zipwire before then re-attaching it to the next successive zipwire, the process continuing until the adventure course has been completed.

Zipwire trolleys typically include a pair of in-line flanged rollers secured by respective axles to a frame of generally inverted "U"-shape, the frame having an opening below the rollers to permit placement of the rollers onto a zipwire, the opening being closeable via a latch or gate biased to its closed position and openable to allow the zipwire to enter the frame to thereby engage the rollers. Whilst this general arrangement is simple in principle it will be understood that when a load is applied to the lower end of the frame there is a tendancy for it to splay apart or otherwise deform. Although this disadvantage can be obviated by ensuring that the size and thickness of the frame is sufficiently robust to resist the tendency for it to deform under tensile load, nevertheless it will be appreciated that this brings with it the disadvantage that the size and/or weight of the zipwire trolley can be significant and therefore not easily portable.

The foregoing problems are at least partially resolved in the teaching of US6810818 which discloses a double pulley device which again uses a frame of generally inverted "U"-section having an open end by which the rollers can engage the zipwire but where instead of the load being applied to the lower end of the frame it is applied above the zipwire itself by the simple expedient of inserting a karabiner or snap-hook through an aperture in the frame so that loads borne by the karabiner are transmitted to the upper part of the frame tending to squeeze it together rather than splay it apart. However, attaching the karabiner to the body of the trolley in this manner may leave the karabiner vulnerable to high impact side loads when the trolley collides with the end stop system of the zipwire.

The present invention is derived from the realisation that there is a need for a relatively lightweight and simple means of attaching a zipwire trolley or pulley to a zipwire which is easily portable, safe and obviates the foregoing disadvantages.

According to the invention there is provided a zipwire trolley comprising or including a frame of generally inverted "U"-shape and associated at least one zipwire engageable roller, means on the frame below the at least one roller for receiving a load to be carried via a karabiner or sling, and a moveable gate for releasably locking the trolley to a zipwire, characterised in that the gate is generally planar and includes at least one generally planar lug or lug-shaped locking formation co-operable with correspondingly shaped lug(s) or locking formation(s) on or in the frame whereby when the gate is closed the or each lug co-operates with the or each locking formation(s) to provide mechanical support for the frame and gate when the trolley is mounted on the zipwire and under tensile load. With this arrangement the at least one lug fits within its respective correspondingly shaped formation in the frame or the gate in the manner of a jigsaw piece fitting to another jigsaw piece, thereby tending to resist tensile forces acting to separate them. This permits the frame of the trolley to be relatively lightweight since when the gate is closed the frame is no longer mechanically open-ended but instead constitutes a continuous structure or loop capable of resisting any tendency for the frame to be splayed apart or otherwise deformed.

Conveniently, the or each lug, if on the gate, projects from the back-plate forming part of the gate, the back-plate being larger than the or each lug, by which means the or each lug is prevented from extending through and beyond the correspondingly shaped formation(s) in the frame. This is a particularly convenient feature since the or each lug and associated back-plate forming part of the gate can be generally smooth and planar, allowing for the trolley to be easily and simply fitted onto a zipwire and attached by the simple expedient of moving the gate from its normally closed position by pressing the gate against e.g. the bias of a spring.

The trolley advantageously includes as a safety mechanism against the accidental opening of the gate in the form of a stepped latch extendable generally perpendicularly from the rear of the gate and being receivable within a slot in the frame such that the gate can only be opened after the latch has been moved to clear the step, thereby allowing the gate to be fully opened for engagement or dis-engagement of the trolley with a zipwire. The stepped latch and associated slot therefore provide a second level of security for the user of the trolley as the gate can only be opened once the latch is lifted to the extent required to clear the step.

Preferably, the stepped latch is in the form of a cylindrical peg swivelably mounted at one end to the gate and having a neck portion towards the distal or "head" end of the peg of smaller diameter to the peg, the neck portion being co- operable within a correspondingly sized slot in the frame immediately above a larger slot through which the head can protrude. The extent of swivelling movement of the peg is limited by the presence of a step on or in the gate such that upon downward pressure of the head to the extent afforded by the presence of the step the peg thereafter acts as a handle by which, upon further downward pressure, the gate may be opened.

In either or both kinds of latch mechanism the latch itself is preferably spring biased to releasably lock the gate in its closed position.

Conveniently, the or each roller is mounted on bearings and associated axles, the axles being partly hollow along their major axis for the purposes of permitting a lubricant such as grease to be injected therewithin for lubricating the roller bearings. The open end of each axle may include a one-way valve, such as a spring-biased ball co-operable with a flange at the open end of the axle permitting lubricant to only flow towards the centre of the axle and, via a bored hole, to the roller bearings. Conveniently, the flange is annular, having a screw- threaded outer surface co-operable with a screw-threaded bore at the free end of the axle whereby the flange and hence ball and associated spring can be releasably secured within the axle. The invention will now be described, by way of example only, with reference to the accompanying drawings in which:

Figure 1 is a perspective front view of a zipwire trolley according to the invention mounted on a zipwire,

Figure 2 is a side view of the trolley of Figure 1 in its closed position, Figure 3 is a perspective rear view of the trolley of Figure 1 in the closed position as shown in Figure 2,

Figure 4 is a side view of the trolley in Figure 1 in its open position, Figure 5 is a perspective rear view of the trolley of Figure 4 in its open position,

Figure 6 is a detailed perspective view of the opening mechanism of the trolley of Figure 1 ,

Figure 7 is a cross-section of the upper part of the trolley through one of the rollers,

Figure 8 is a side view of an alternative operating mechanism to that shown with reference to Figures 1 to 6,

Figure 9 is a perspective view of the trolley with latch mechanism as shown in Figure 8,

Figure 10 is a sectional side view of the trolley shown in Figure 8, and

Figure 11 is a side view of the trolley of Figure 8 in which the gate is shown in its open position.

Referring firstly to Figure 1 a zipwire trolley shown generally at 1 includes a trolley frame 2 of generally inverted "U"-shape having a front-plate 2a and a rear-plate 2b between which are sandwiched a pair of axles 3 and associated flanged rollers 4, one of which is shown more clearly in Figure 7.

At the lower end of the rear-plate 2b is an aperture defining an eye 5 for receiving a karabiner 6 or other load-carrying means such as a sling or strap. Above the eye 5 are a pair of ribs 7 extending from the rear-plate 2b for receiving acorrespondingly slotted gate 8 pivotally mounted on the ribs 7 via a pivot pin 9 as shown in Figure 2, the gate 8 being biased to the closed position shown in Figure 2 via a spring (not shown).

At the end of the gate 8 remote from the pivot pin 9 are a pair of part circular lugs 10 received within a pair of correspondingly shaped locking formations 11 in the front-plate 2a so that they inter-engage in the manner of a pair of interlocking jigsaw pieces.

As shown more clearly with reference to Figure 6 the lugs 10 project from a back-plate 12 forming part of the gate 8 such that the lugs 10 are prevented from extending through the apertures 11 beyond the limit imposed by the back- plate 12. Hence, in the condition shown in Figure 2 the gate 8 is effectively structurally connected to and forms part of the frame 2 such that tensile loads applied to the eye 5 are transmitted directly to the rear-plate 2b and indirectly to the front-plate 2a via the gate 8 and associated lugs 10. This arrangement is particularly convenient because it allows the frame 2 to be made from relatively thin-walled front and rear-plates 2a, 2b without compromising the integrity of the frame when under load. In addition, because the lugs 10 do not extend beyond the major plane of the gate 8 they do not interfere with or otherwise snag against the zipwire Z as the trolley 1 is being mounted or dis-mounted. The presence of the back-plate 12 immediately behind the lugs 10 and the biasing of the gate 8 towards the apertures 11 in the front-plate 2a provide a first safety mechanism whereby the gate 8 is biased to its closed position as shown in Figure 2. However, in another aspect the invention also includes a second safety feature in the form of a stepped latch 13 extending perpendicularly from a latch pin 14 and associated latch receiving recess (not shown) in the rear of the gate 8, the latch 13 being receivable within a correspondingly shaped slot 15 (shown in Figures 3 and 5) by which the step 16 can be lifted to the position shown in Figures 4 and 5 in which the gate 8 can become fully opened. This stepped latching mechanism therefore provides an additional safety feature such that accidental pressure on the closed gate 8 will not cause it to be opened and thereby present a safety hazard, it being necessary to lift the latch 13 before the gate 8 can be moved to its open position.

In a further refinement to the invention and as shown in Figure 7, each axle 3 is partially hollow at one end to allow for lubrication of bearings 17 for each roller 4. The open end 18 of the axle 3 is closed by a threaded flange 19 which acts as a valve seat against a ball bearing 20 biased by spring 21 against the flange 19. A bored hole 22 of smaller diameter than the spring 21 leads to the bearings 17 such that a lubricant such as grease can be pumped under pressure beyond the ball bearing 20 as required, whereafter the ball bearing 20 serves to seal access to the conduit 22 by contaminants such as water including saltwater which could otherwise lead to corrosion of the bearings 17. This arrangement also means that the rollers 4 and attendant bearings 17 do not have to be removed from the frame 2 when the zipwire trolley 1 is being serviced Turning now to the embodiment of the invention shown with reference to Figures 8 to 11 , the latch mechanism in this instance comprises a cylindrical peg

23 swivelably mounted at one end to the gate 8a via a pivot pin 14a and having at its distal end a head portion 24 of corresponding diameter to the peg portion 23, and there between a neck portion 25 of smaller diameter so that it can fit within a correspondingly-sized slot 26 immediately above a larger-diameter slot 27 in the rear plate 2b as shown in Figure 12. In the position shown the head

24 of the pin 23 is at an intermediate position in which the neck portion 25 can be forced into the slot 26 by the action of a biasing spring (not shown) or it can instead be forced downwards to the position shown in Figure 11 by thumb- pressure, in which position the gate 8a is forced to the open position shown, thereby allowing the trolley to be mounted or dismounted onto or from a zipwire. The gate 8a includes a stepped recess 28 limiting the swivelling movement of the peg 23 to the extent afforded by the lower end of the slot 27, corresponding to the maximum extent of swivelable travel of the gate 8a from the fully closed position shown in Figure 8 to the fully opened position shown in Figure 11. Thus, with this embodiment of the invention the gate 8a can be manually opened from the rear by downward pressure on the head 24.

The invention in its various aspects therefore provides a relatively lightweight zipwire trolley which can be easily attached and detached from a zipwire without the risk of accidental entanglement as the zipwire passes the gate 8, which itself can only open after operation of the latch 13 extending out of the slot 15 in the rear plate 2b, although it will be understood that the provision of the latch mechanism itself is an optional feature of the invention. Similarly, the invention is not limited to the provision of the lubrication mechanism shown with reference to Figure 7 and although two lugs 9 and associated apertures 10 are shown it will be understood that only one or more than two lugs may be provided as required. Similarly, the lugs may be of inverted form extending from the front-plate 2a with correspondingly shaped apertures in the gate 8 to thereby provide a mechanical connection between the front and rear-plates 2a, 2b when under tensile load. The lugs and corresponding locking formations may be of any suitable shape, although part-circular is preferred for simplicity of manufacture and also because lugs of that shape are less likely to snag the zipwire.

Claims

Claims

1) A zipwire trolley (1) comprising or including a frame (2) of generally inverted "U"-shape and associated at least one zipwire engageable roller (4), means (5) on the frame below the at least one roller for receiving a load to be carried via a karabiner or sling, and a moveable gate (8) for releasably locking the trolley to a zipwire, characterised in that the gate (8) is generally planar and includes at least one generally planar lug or lug-shaped locking formation (10) co-operable with correspondingly shaped lug(s) or locking formation(s) ( 1) on or in the frame whereby when the gate is closed the or each lug co-operates with the or each locking formation(s) to provide mechanical support for the frame and gate when the trolley is mounted on the zipwire and under tensile load.

2) A zipwire trolley according to Claim 1 and further characterised in that the or each lug, (10) if on the gate, (8) projects from a back-plate, (12) forming part of the gate, the back-plate being larger than the or each lug, by which means the or each lug is prevented from extending through and beyond the correspondingly shaped formation(s) in the frame.

3) A zipwire trolley according to Claim 1 or Claim 2 further characterised including a safety mechanism (13, 15, 16) against the accidental opening of the gate (8) in the form of a stepped latch (13, 23) extendable generally perpendicularly from the rear of the gate and being receivable within a slot (15, 25) in the frame (2) such that the gate can only be opened after the latch has been moved to clear the step, thereby allowing the gate to be fully opened for engagement or dis-engagement of the trolley with a zipwire.

4) A zipwire trolley according to Claim 3 further characterised in the stepped latch is in the form of a cylindrical peg (23) swivelably mounted at one end to the gate (8a) and having a neck (25) portion towards the distal or "head" end (24) of the peg of smaller diameter to the peg, the neck portion being co-operable within a correspondingly sized slot (26) in the frame (2) immediately above a larger slot (27) through which the head can protrude.

5) A zipwire trolley according to Claim 4 and further characterised in that the extent of swivelling movement of the peg (23) is limited by the presence of a step (28) on or in the gate (8a) such that upon downward pressure of the head (24) to the extent afforded by the presence of the step the peg thereafter acts as a handle by which, upon further downward pressure, the gate may be opened.

6) A zipwire trolley according to Claim 3 or Claim 4 further characterised in that the latch (13, 23) itself is spring biased to releasably lock the gate (8, 8a) in its closed position.

7) A zipwire trolley according to any preceding Claim 1 further characterised in that the or each roller (4) is mounted on bearings (17)and associated axles, (3) the axles being partly hollow (22) along their major axis for the purposes of permitting a lubricant such as grease to be injected therewithin for lubricating the roller bearings. 8) A zipwire trolley according to Claim 7 further characterised in that the open end (18) of each axle includes a one-way valve in the form of a spring-biased ball (20) co-operable with a flange (19)at the open end of the axle (3) permitting lubricant to only flow towards the centre of the axle and, via a bored hole, (22) to the roller bearings (17).

9) A zipwire trolley according to Claim 8 further characterised in that the flange

(19) is annular, having a screw-threaded outer surface co-operable with a screw- threaded bore (18) at the free end of the axle (3) whereby the flange and hence ball

(20) and associated spring (21) can be releasably secured within the axle.

10) A zipwire trolley substantially as hereinbefore described with reference to Figures 1 to 7 or 8 to 12.