WO2010081202A2

WO2010081202A2 - Self-retracting lifeline

Info

Publication number: WO2010081202A2
Application number: PCT/AU2010/000046
Authority: WO
Inventors: Michael Bermeio
Original assignee: Roofsafe-T-Systems Pty Limited
Priority date: 2009-01-19
Filing date: 2010-01-19
Publication date: 2010-07-22
Also published as: AU2010205907B2; AU2010205907A1; WO2010081202A3

Abstract

A self-retracting safety line device (10) comprising a casing (12), a cable (18) retractably dispensable from the casing (12) and mounted on a spool (14) in the casing (12), capable of movement in two directions, a spool spring to bias the spool (14) in one direction; a locking mechanism (24) to selectively lock the safety line device (10), two locking rings (30, 32) with serrations facing in opposite directions and two sets of inertia pins (40, 42) mounted to an inertia disc (38) fixed relative to the spool (14) and adjacent the locking rings (30, 32), where high accelerating rotation of the spool (14) in the first direction causes braking of the cable (18) in the first direction, and high accelerating rotation of the spool (14) in the second direction causes the cable (18) to brake in the second direction.

Description

SELF-RETRACTING LIFELINE

Field of Invention

The present invention relates to a self-retracting lifeline for arresting the fall of a user operating at dangerous heights.

Background

Retractable spooled safety lines are used as personal safety lines by individual workers operating at dangerous heights and allow the worker to move around laterally, for example on a rooftop, while being anchored to a fixed point. As the worker moves away from the fixed point, the cable of the safety line uncoils and as the worker moves closer to the fixed point, the cable recoils on the spool, maintaining tension on the cable. In the event of a fall, an inertia activated locking mechanism engages the spool and prevents further uncoiling of the cable, arresting the worker's fall.

Horizontal safety lines secured at each end are used by groups of workers operating in a common area. Each worker has a personal safety line connected to the horizontal safety line by way of a karabiner and can move lengthways along the horizontal safety line and laterally to the extent that their personal safety line allows. In order to install a horizontal safety line, a worker typically secures one end of a spooled safety line to the building and carries the other end of the cable to a distant location and secures it, before ratcheting the line taught. Such lines do not typically have inertia activated locking mechanisms, meaning that the worker would require a further personal safety line while installing and uninstalling the safety line. These lines are also not typically self-retracting due to the danger to other workers of an accidentally released safety line retracting at great speed and whipping about the work area.

Consequently, different types of safety lines are typically used for personal safety lines and horizontal safety lines at the expense of safety, efficiency and convenience.

The present inventors have now developed a new safety line device.

Disclosure of Invention

Accordingly, in a first aspect, the present invention provides a self-retracting safety line device comprising: a casing; a spool mounted in the casing on a shaft for rotation in a first direction and an opposite second direction; a cable retractably dispensable from the casing, the cable being mounted on the spool and having a free end extending from the casing; a spool spring biasing the spool to rotate in one of the first or second directions; a locking mechanism adapted to selectively lock the device and prevent dispensing of the cable; a first locking ring fixed relative to the casing, the first locking ring having a serrated inner circumference with serrations oriented in a first circumferential direction; a second locking ring fixed relative to the casing, the second locking ring having a serrated inner circumference with serrations oriented in a second circumferential direction, opposite to the first circumferential direction; an inertia disc fixed relative to the spool and arranged adjacent to the locking rings; a first inertia pin having a proximal end pivotally mounted to the inertia disc and a distal end biased radially inwardly of the inertia disc, the distal end being located within the inner circumference of the first locking ring; and a second inertia pin having a proximal end pivotally mounted to the inertia disc and a distal end biased radially inwardly of the inertia disc, the distal end being located within the inner circumference of the second locking ring; wherein accelerating rotation of the spool in the first direction causes the first inertia pin to pivot radially outwardly of the inertia disc until the distal end of the first inertia pin engages the serrations of the first locking ring and prevents further rotation of the spool in the first direction; and wherein accelerating rotation of the spool in the second direction causes the second inertia pin to pivot radially outwardly of the inertia disc until the distal end of the second inertia pin engages the serrations of the second locking ring and prevents further rotation of the spool in the second direction.

In a preferred embodiment, the first locking ring is arranged between the inertia disc and the second locking ring. Preferably, the distal end of the first inertia pin comprises a tooth adjacent the inertia disc and arranged within the first locking ring and the distal end of the second inertia pin comprises a tooth spaced from the inertia disc and arranged within the second locking ring. In a preferred embodiment, the first and second inertia pins are mounted on the inertia disc via first and second shafts, such that the first inertia pin pivots substantially parallel and adjacent to the inertia disc and the second inertia pin pivots parallel to the inertia disc and is spaced from the inertia disc by the second shaft. Preferably, the safety line device includes a pair of the first inertia pins and a pair of the second inertia pins.

In a preferred embodiment, the locking mechanism is a spool lock adapted to selectively lock the spool and prevent rotation of the spool. Preferably, the locking mechanism comprises a retractable pin aligned with an aperture in the housing and locking rings, wherein the pin is adapted to retractably extend into the casing, through the locking rings and into a pin hole in the inertia disc. Further preferably, the inertia disc has a plurality of pin holes. Alternatively, the locking mechanism is a selectively releasable cable clamp. Preferably, the locking mechanism is actuated by way of an actuator mounted externally on the casing.

Optionally, the casing includes a pair of casing halves and a frame clamped between the casing halves and having a handle projecting from the casing. Preferably, the frame includes a mounting flange projecting from the casing and the safety line device includes a mounting plate having a bracket for receiving and securing the mounting flange.

Preferably, the free end of the cable incorporates a force attenuator.

In a preferred embodiment, the safety line device includes a ratchet mechanism to facilitate manual winding or unwinding of the cable. Preferably, the ratchet mechanism is releasably coupled to the device.

Throughout this specification, unless the context requires otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is solely for the purpose of providing a context for the present invention. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed in Australia before the priority date of each claim of this specification.

In order that the present invention may be more clearly understood, preferred embodiments will be described with reference to the following drawings and examples. Brief Description of the Drawings

Figure 1 depicts a safety line device;

Figure 2 is a cross-sectional view of the safety line device of Figure 1 ;

Figure 3 depicts the inertia disc of the device of Figure 1;

Figure 4 depicts the inertia disc and locking rings of the device of Figure 1 in an at rest state; and

Figure 5 depicts the inertia disc and locking rings of Figure 4 in a locked state.

Mode(s) for Carrying Out the Invention

Referring to Figures 1 and 2, the safety line device 10 comprises a casing 12 housing a spool 14, the spool 14 being mounted on a shaft 16 for rotation in a first direction and an opposite second direction. The device 10 includes a cable 18 having a fixed end attached to the spool 14 and a free end extending from an opening in the casing 12. The spool 14 is biased by a spool spring (not shown) to rotate in one of the first or second directions. As shown in Figure 2, the device 10 includes a clutch mechanism 22 associated with the spool 14. A manual lock mechanism 24 comprising a retractable pin 26 is mounted on the casing 12 and is aligned with an aperture 28 extending into the casing 12.

As best depicted in Figures 4 and 5, the device 10 further comprises first and second locking rings 30, 32 fixed inside the casing 12, with the first locking ring 30 having a serrated inner circumference with serrations 34 oriented in a first circumferential direction and the second locking ring 32 having a serrated inner circumference with serrations 36 oriented in a second circumferential direction, opposite to the first circumferential direction. The aperture 28 extends through the two locking rings 30, 32.

As shown separately in Figure 3, an inertia disc 38 is fixed to the spool 14 and arranged adjacent to the locking rings 30, 32. First and second pairs of inertia pins 40, 42 are pivotally mounted on the inertia disc 38. Each pin of the first pair of inertia pins 40 has a proximal end 44 pivotally mounted to the inertia disc 38 and a distal end 46 biased radially inwardly of the inertia disc 38. The distal end 46 of each of the first inertia pins 40 comprises a tooth and is located within the inner circumference of the first locking ring 30. Each pin of the second pair of inertia pins 42 has a proximal end 48 pivotally mounted to the inertia disc 38 and a distal end 50 biased radially inwardly of the inertia disc 38. The distal end 50 of each of the second inertia pins 42 comprises a tooth and is located within the inner circumference of the second locking ring 32. A plurality of pin holes 52 are formed in the inertia disc 38, which align with the aperture 28 as the inertia disc 38 spins.

As depicted in Figure 1, the device 10 has an optional force attenuator 54 mounted at the free end of the cable 18. The force attenuator 54 acts to reduce the impact forces transferred to a user when a fall is suddenly arrested. A suitable force attenuator 54, for example, is a polyutherine force attenuator capable of reducing forces on a person or structure to at least 6 kN.

A ratchet mechanism (not shown) may be attached to, or incorporated into, the device 10 to apply tension to the cable 18.

In operation as a personal safety line, the device 10 is anchored and a worker attaches a harness to the free end of the cable 18. As the worker moves around and away from the device 10, the spool 14 is free to unwind in the first direction against the bias of the spool spring (not shown). As the worker nears the device 10 again, the spool spring (not shown) winds any slack in the cable 18 back onto the spool 14 in the second direction. Should the worker fall, the rapid acceleration of the spool 14 in the first direction would cause the first inertia pins 40 to pivot radially outwardly of the inertia disc 38 until the distal ends 46 of the first inertia pins 40 engage the serrations 34 of the first locking ring 30 and prevent further rotation of the spool 14 in the first direction, thereby arresting the fall of the worker.

If the device 10 is used as a horizontal safety line, the worker anchors the device 10 at a first anchor point and connects the free end of the cable 18 to his harness. The worker then moves to a second anchor point, while the device 10 acts as a personal safety line protecting the worker from a fall as described above. Upon reaching the second anchor point, the worker disconnects the free end of the cable 18 from his harness and mounts it at the second anchor point.

If the worker was to accidentally release the free end while securing or disconnecting it, the free end of the cable 18 would recoil rapidly as the spool 14 rotates in the second direction under the bias of the spool spring (not shown), in order to wind the cable 18 back onto the spool 14. The rapid acceleration of the spool 14 in the second direction would cause the second inertia pins 42 to pivot radially outwardly of the inertia disc 38 until the distal ends 50 of the second inertia pins 42 engage the serrations 36 of the second locking ring 32 and prevent further rotation of the spool 14 in the second direction, thereby arresting the recoil of the free end of the cable 18. The worker then attaches a separate safety line, eg. a lanyard, to the cable 18 to return to the first anchor point. If the worker falls during this journey, the personal safety line would pull on the cable 18 and the device 10 would lock in the same way as described above. Upon returning to the first anchor point, the worker actuates the manual lock mechanism 24, installing the pin 26 through the aperture 28 and into one of the pin holes 52. With the cable 18 locked, the worker can then tension the cable 18 using the ratchet mechanism (not shown). The device 10 can then be used as a conventional horizontal safety line.

If two workers were involved in the installation, once the first worker reached the second anchor point, the second worker could lock and tension the cable 18 at the first anchor point.

The manual lock mechanism 24 also acts to prevent the spool 14 from winding outwards as tension is applied to the cable 18 with the ratchet mechanism (not shown). This ensures that the cable 18 can be tehsioned to the required parameters while still retaining its inertia locking capabilities.

Advantageously, the design of the device 10 allows it to be used as either a personal safety line or as a horizontal multiple user safety line. Further, even as a horizontal safety line, the device 10 has inbuilt force attenuation capability. It is further advantageous that the cable 18 can be manually locked or unlocked to allow different operations.

The device 10 advantageously incorporates inertia locking mechanisms that operate in both the winding and unwinding directions. This provides added safety benefits and allows the device 10 to be utilised for a greater range of applications.

It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Claims

Claims:

1. A self-retracting safety line device comprising: a casing; a spool mounted in the casing on a shaft for rotation in a first direction and an opposite second direction; a cable retractably dispensable from the casing, the cable being mounted on the spool and having a free end extending from the casing; a spool spring biasing the spool to rotate in one of the first or second directions; a locking mechanism adapted to selectively lock the device and prevent dispensing of the cable; a first locking ring fixed relative to the casing, the first locking ring having a serrated inner circumference with serrations oriented in a first circumferential direction; a second locking ring fixed relative to the casing, the second locking ring having a serrated inner circumference with serrations oriented in a second circumferential direction, opposite to the first circumferential direction; an inertia disc fixed relative to the spool and arranged adjacent to the locking rings; a first inertia pin having a proximal end pivotally mounted to the inertia disc and a distal end biased radially inwardly of the inertia disc, the distal end being located within the inner circumference of the first locking ring; and a second inertia pin having a proximal end pivotally mounted to the inertia disc and a distal end biased radially inwardly of the inertia disc, the distal end being located within the inner circumference of the second locking ring; wherein accelerating rotation of the spool in the first direction causes the first inertia pin to pivot radially outwardly of the inertia disc until the distal end of the first inertia pin engages the serrations of the first locking ring and prevents further rotation of the spool in the first direction; and wherein accelerating rotation of the spool in the second direction causes the second inertia pin to pivot radially outwardly of the inertia disc until the distal end of the second inertia pin engages the serrations of the second locking ring and prevents further rotation of the spool in the second direction.

2. The device of claim 1 wherein the first locking ring is arranged between the inertia disc and the second locking ring.

3. The device of claim 2 wherein the distal end of the first inertia pin comprises a tooth adjacent the inertia disc and arranged within the first locking ring and the distal end of the second inertia pin comprises a tooth spaced from the inertia disc and arranged within the second locking ring.

4. The devjce of claim 3 wherein the first and second inertia pins are mounted on the inertia disc via first and second shafts, such that the first inertia pin pivots substantially parallel and adjacent to the inertia disc and the second inertia pin pivots parallel to the inertia disc and is spaced from the inertia disc by the second shaft.

5. The device of any one of claims 2 to 4 wherein the safety line device includes a pair of the first inertia pins and a pair of the second inertia pins.

6. The device of any one of the preceding claims wherein the locking mechanism is a spool lock adapted to selectively lock the spool and prevent rotation of the spool.

7. The device of claim 6 wherein the locking mechanism comprises a retractable pin aligned with an aperture in the housing and¹ locking rings, wherein the pin is adapted to retractably extend into the casing, through the locking rings and into a pin hole in the inertia disc.

8. The device of claim 7 wherein the inertia disc has a plurality of pin holes.

9. The device of any one of claims 1 to 5 wherein the locking mechanism is a selectively releasable cable clamp.

10. The device of any one of the preceding claims wherein the locking mechanism is actuated by way of an actuator mounted externally on the casing.

11. The device of any one of the preceding claims wherein the casing includes a pair of casing halves and a frame clamped between the casing halves and having a handle projecting from the casing.

12. The device of claim 11 wherein the frame includes a mounting flange projecting from the casing and the safety line device includes a mounting plate having a bracket for receiving and securing the mounting flange.

13. The device of any one of the preceding claims wherein the free end of the cable incorporates a force attenuator.

14. The device of any one of the preceding claims wherein the safety line device includes a ratchet mechanism to facilitate manual winding or unwinding of the cable.

15. The device of claim 14 wherein the ratchet mechanism is releasably coupled to the device.