GB2572971A

GB2572971A - Adjustable harness

Info

Publication number: GB2572971A
Application number: GB1806254.7A
Authority: GB
Inventors: Andrew Farnaby James
Original assignee: Draeger Safety UK Ltd
Current assignee: Draeger Safety UK Ltd
Priority date: 2018-04-17
Filing date: 2018-04-17
Publication date: 2019-10-23
Also published as: GB201806254D0; WO2019202316A1

Abstract

The harness comprises an adjustable back plate for accommodating a breathing gas delivery system which is adjustable between a contracted position and an extended position and comprises a biasing mechanism configured to bias the back plate towards the contracted position. The back plate may comprise an upper element or yoke 122 having two longitudinally extending rails 126 and a lower element 124 with channels 132 for receiving the rails. The biasing mechanism may comprise a spring element 136 which is extended by relative movement of the upper and lower elements. Also disclosed is a breathing apparatus comprising the harness, shoulder straps, and a waist belt.

Description

The present invention relates to an adjustable harness for use with self-contained breathing apparatus (SCBA) having an improved body length adjusting system.

SCBAs are generally used by emergency services personnel when they enter an environment which has reduced or no safe breathable air, such as the scene of a fire or a gas leak. SCBA harnesses generally comprise a back plate, a pair of shoulder straps and a waist belt. The back plate is provided with a first stage pressure reduction valve towards the lower end and a retaining strap. In use, a cylinder of breathable gas is attached to the first stage pressure reduction valve and is secured to the back plate by means of the retaining strap. One or more flexible hoses extended from the first stage pressure reduction valve to the shoulder straps so that breathing apparatus worn by the user may be conveniently connected thereto.

It is desirable for a SCBA harness, and in particular the back plate, to be adjustable in length. This allows it to be comfortably worn by users of different heights, who may have differing distances between their waist and shoulders. There are known harnesses which permit adjustment of the back plate length, which generally provide a number of incremental fixed adjustment lengths. However, these fixed lengths may not provide suitably fine adjustment for users whose body size falls between the fixed lengths provided, which can result in an uncomfortable or ineffective fit.

However, in these previously considered harnesses, adjustment of the length of the back plate is a time-consuming and inefficient task which must be performed before the SCBA harness is donned. For example, if the adjustment is incorrect for the user, the SCBA harness must then be doffed, further adjusted, and then re-donned. This can waste valuable time at the scene which can delay an emergency response. In the alternative, if there is not sufficient time for the user to adjust the back plate, then this may result in them wearing an incorrectly-sized harness which could impair their effective use of the SCBA.

Therefore, it will be understood that it is desirable to provide an improved harness for an SCBA which enables quicker and easier length adjustment.

According to a first aspect, there is provided a harness for a breathing apparatus comprising an adjustable back plate for accommodating a breathing gas delivery system, the back plate being adjustable between a contracted position and an extended position;

and a biasing mechanism configured to bias the back plate towards the contracted position.

The back plate may comprise an upper back plate element for attachment to at least one shoulder support and a lower back plate element for attachment to a waist support. The upper and lower back plate elements may be moveable relative to each other to adjust the back plate between the contracted position and the extended position. In the contracted position, the back plate may have a first length, and in the extended position, the back plate may have a second length longer than the first length.

The back plate, and in particular, the upper and lower back plate elements, may be freely moveable between the contracted and extended positions. It should be understood that by “freely moveable” it is meant that the upper and lower back plate elements can be moved relative to one another without any obstruction other than the resilient biasing force between the two back plate elements. There may be no other resistance to relative movement between the upper and lower back plate elements across the range of movement between the contracted and extended positions.

The upper and lower back plate elements may be maintained at any intermediate position between the contracted and extended positions if appropriate opposing force is applied to counteract the resilient biasing therebetween. For example, during use of the harness, the weight of the SCBA and the securing of the waist support to the user’s waist and the securing of the shoulder support to the user’s shoulder may maintain the length of the back plate in the contracted position, the extended position, or any intermediate position therebetween. The resilient biasing of the upper and lower back plate elements may automatically adjust the length of the back plate to the length of the user’s back. The resilient biasing may automatically adjust the length of the back plate to the shortest possible length for the particular user. It is noted that in this disclosure, the contracted and extended positions of the upper and lower back plate elements may also be referred to generally as contracted or extended positions of the back plate as a whole.

The back plate may be adjustable over a range of at least 25mm, 50mm, 75mm, 100mm, or 125mm. In a particular examples, the back plate may be adjustable over a range of 100mm-125mm. The back plate may be continuously adjustable over the adjustment range. The adjustment range may be a length adjustment range. In a fully contracted position, the back plate may have a first length and, in a fully extended position, the back plate may have a second length which is longer than the first length by the total adjustment range. For example, if the adjustment range was 100mm and the fully contracted length of the back plate was 1000mm, then the fully extended length of the back plate would be 1100mm.

The harness may further comprise a contraction stop mechanism configured to prevent contraction of the back plate beyond the contracted position. The contraction stop mechanism may be a physical element which engages with the upper and/or lower back plate elements to prevent further contracting movement of the back plate. The contraction stop mechanism may comprise a resilient buffer or stop element to prevent jarring when the stop mechanism is engaged or contacted. The compression stop mechanism may prevent or inhibit the upper and lower back plate elements from becoming disengaged and/or may prevent damage to the resilient biasing means by over-compression.

The harness may further comprise an extension stop mechanism configured to prevent extension of the back plate beyond the extended position. The extension stop mechanism may be a physical element which engages with the upper and/or lower back plate elements to prevent further extending movement of the back plate. The extension stop mechanism may comprise a resilient buffer or stop element to prevent jarring when the stop mechanism is engaged or contacted. The extension stop mechanism may prevent or inhibit the upper and lower back plate elements from becoming disengaged and/or may prevent damage to the resilient biasing means by over-extension.

The upper and lower back plate elements may be movable relative to each other in a longitudinal direction. The longitudinal direction may be a longitudinal direction with respect to the back plate (i.e. a vertical direction of the back plate in use). The upper and lower back plate elements may be moveable longitudinally in an arched manner so as to follow a contour or shape of the user’s back or torso.

The upper and lower back plate elements may each comprise complimentary longitudinally-extending features for being slidably engaged to thereby slidably adjust the back plate between the contracted and extended positions.

In some examples, at least one of the upper and/or lower back plate element may comprise at least one longitudinally-extending rail for being slidably engaged with the other of the upper or lower back plate element to thereby slidably adjust the back plate between the contracted and extended positions.

In an example, the upper back plate element may comprise first and second longitudinally-extending rails and the lower back plate element may comprise first and second complimentary longitudinally-extending channels for slidably receiving the first and second longitudinally-extending rails of the upper back plate element. The upper back plate element may further comprise a laterally-extending shoulder strap fixing portion for attachment to first and second shoulder straps at opposing lateral sides of the upper back plate element. In another example, the lower back plate element may comprise the rails, and the upper back plate element may comprise the complimentary channels.

The harness may further comprise a spring element configured to resiliently bias the upper and lower back plate elements towards the contracted position.

The spring element may be configured to apply a biasing or restorative force to bias the upper and lower back plate elements towards the contracted position. The spring element may be a mechanical spring or a pneumatic spring, such as a compressible gas cylinder spring (i.e. a compression spring) or an extendable vacuum cylinder spring (i.e. a tension spring). In other examples, the resilient biasing may be provided exclusively or additionally by a magnetic arrangement which applies a magnetic force to bias the upper and lower back plate elements to the contracted position.

The spring element may be configured such that, when the upper back plate element is supported on a user’s shoulders in use, the total weight of the lower back plate element and any components to be attached thereto at least partially counteracts the resilient biasing of the upper and lower back plate elements to thereby assist the extension of the back plate towards the extended position.

The means for providing the resilient biasing, such as a spring, may be encapsulated within a protective housing. The housing may protect the resilient biasing means from damage, tampering, ingress of dirt or dust, and present objects from being trapped in the biasing means, for example in the extended coils of a tension spring.

The spring element may be configured to be extended by relative movement of the upper and lower back plate elements in the longitudinal direction from the contracted to extended position.

The spring element may be configured to be compressed by relative movement of the upper and lower back plate elements in the longitudinal direction from the contracted to extended position. In other words, the spring element may be a compression spring.

The upper back plate element may be an upper yoke. The upper back plate element may configured for attachment to upper end of shoulder support. The shoulder support may comprise one or more shoulder straps.

The lower back plate element may be a back plate frame or a major structural component of the back plate. The lower back plate element may be configured for attachment to a waist support, such as a waist belt for securing the lower back plate element to a user’s waist. In some examples, the lower back plate element may be also be configured to be attached to lower end of shoulder strap.

The upper and lower back plate elements may be moveable relative to each other in a longitudinal direction of the back plate to thereby adjust a longitudinal distance between the waist support and the shoulder support.

The breathing gas delivery system may be a compressed breathing gas cylinder or a closed circuit breathing system. The closed circuit breathing system may comprise a compressed oxygen cylinder and a carbon dioxide scrubber, such as a soda lime scrubber.

According to a second aspect, there is provided a breathing apparatus comprising a harness according to the first aspect described above, left and right shoulder straps, and a waist belt. An upper end of each shoulder strap is attached to the upper back plate element and the waist belt is attached to the lower back plate element. Relative movement between the upper and lower back plate elements of the back plate adjusts a distance between the upper ends of the left and right shoulder straps and the waist belt to thereby permit the breathing apparatus to be worn by a plurality of different users having different back lengths without manual adjustment.

The breathing apparatus may be an SOBA (self-contained breathing apparatus) or a SCUBA (self-contained underwater breathing apparatus) or a CCBA (Closed Circuit Breathing Apparatus). The breathing apparatus may further comprise one or more of a breathing gas cylinder or cylinders, and breathing gas hoses.

It should be understood that, except where mutually exclusive, any features described with respect to the first aspect could equally be applied to the harness of the second aspect.

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which:

Figure 1 shows a front view of a harness according to an embodiment of the invention, wherein the harness is in an extended position;

Figure 2 shows a back view of a harness according to an embodiment of the invention, wherein the harness is in a contracted position; and

Figure 3 shows a back view of a harness according to an embodiment of the invention, wherein the harness is in an extended position.

Referring to Figure 1, the harness 100 comprises a back plate 102, a pair of lengthadjustable shoulder straps 104,106 and a length-adjustable waist belt 108. The upper ends 110,112 of shoulder straps 104, 106 are fixed to an upper portion of the back plate 102 and the belt 108 is fixed to a lower portion of the back plate 102. A valve 114 is provided at the bottom of the back plate 102. In use, a cylinder of breathable gas (not shown) is connected to the valve 114 and it is retained by the back plate 102 and a retaining strap 116. Two air supply hoses, or conduits, 118, 120 are connected to the valve for supplying breathable gas, one to the breathing apparatus of the harness wearer and one to a pressure gauge. The hoses 118, 120 extend substantially longitudinally from the valve 114 and pass through an opening in the back plate 102 to the inside (or ‘back’) of the back plate 102. In addition, or instead, one or more of the conduits may be an electrical cable.

For the avoidance of doubt, this side of the harness 100 and back plate 102 will be referred to as the ‘front’. In use, this side of the harness 100 will face away from the wearer’s back. The opposing side of the harness 100 and back plate 102, shown in Figures 2 and 3, will be referred to as the ‘back’, as it faces the user’s back and is therefore not visible in use.

The back plate 102 of the harness 100 comprises two parts: an upper back plate element 122 and a lower back plate element 124, which will be referred to as an upper yoke 122 and a back plate frame 124 (or frame 124) respectively. The upper yoke 122 and back plate frame 124 are configured to be moveable relative to one another such that the total length of the back plate 102 is adjustable.

The upper yoke 122 comprises a pair of spaced-apart parallel rails 126, which extend in the longitudinal direction with respect to the harness 100 and back plate 102 (i.e. generally vertically). The rails 126 are connected at their respective upper ends to a laterally-extending fixing portion 128 for the shoulder straps 104,106. The upper ends 110, 112 of the shoulder straps 104,106 are attached to the fixing portion 128 with releasable connections to permit their removal for cleaning and maintenance. It will be understood that the upper yoke 122 generally forms an ‘n’ shape, with the rails 126 extending vertically downward from the shoulder strap fixing portion 128. The rails 126 comprise conduit channels formed therein for receiving the conduits 118,120 and routing them to the shoulder straps 104,106. In some other examples, the upper yoke 122 could be flexible to permit the yoke 122, when extended from the frame 124, to comply with the curvature of a user’s back. For example, the rails 126 could be made to be resiliently deformable away from the longitudinal axis of the rail 126.

The back plate frame 124 forms the major structural component of the back plate 102. The waist belt 108 is attached to a lower part of the frame 124, the first stage pressure reduction valve 114 and other gas-handling components are provided on the frame 124, and the cylinder of breathable gas (not shown) is secured to and supported by the frame 124. It should be understood, however, that in alternative examples, some of these parts may be provided on the upper yoke 122. In this example, the lower ends 129,130 of the shoulder straps 104,106 are attached to the frame 124, but in other examples, they may be attached to the upper yoke 122, or the waist belt 108.

The frame 124 comprises a pair of channels 132 which extend longitudinally with respect to the back plate 102. The channels 132 are spaced apart by substantially the same distance as the rails 126 of the upper yoke 122 and are sized so as to slidably receive the rails 126 therein. For visibility of the yoke 122 and the frame 124, in this example, the back plate 102 (i.e. the upper yoke 122 and frame 124) are shown in an extended position, whereby the rails 126 are mostly retracted from the channels 132 such that the back plate 102 has an enlarged length. It will be appreciated that the distal ends of the rails 126 remain within the channels 132 to prevent the back plate 102 from becoming inadvertently disassembled. An extension stop mechanism 134 is provided to prevent the rails 126 of upper yoke 122 from 124 completely withdrawing from the channels 132 of the frame 124. This extension stop mechanism 134 therefore defines the maximum extension, and thus the maximum length, of the back plate 102. In this example, the rails 126 (and therefore the upper yoke 122) may extend from the frame 124 by around 125mm before the extension stop mechanism 134 is engaged.

It should be understood that the upper yoke 122 is slidably attached to the frame 124 in such a way that it can move longitudinally with respect to the frame 124 between the fully extended position shown in Figure 1 and the fully contracted position shown in Figure 2. The upper yoke 122 is generally freely slidable between the positions between the fully extended position and the fully contracted position, notwithstanding the biasing which will be discussed below. Accordingly, the total length of the back plate 102 can be adjusted in order to allow it to be comfortably worn by users of different heights or back lengths.

Referring now to Figure 2, the harness 100 is shown from the rear. In this view, the back plate 102 is in the fully contracted position, in which the rails 126 of the upper yoke 122 are fully received within the channels 132 of the frame 124. In this configuration, the back plate 102 has its shortest possible total length. Figure 2 also illustrates the configuration of the back plate 102 when it is not being worn. As illustrated, the rails 126 each comprise a channel for housing a conduit 135. The waist belt 108 of the harness 100 is not shown in this view to enable other components of the back plate to be seen.

Near the bottom portion of the frame 124, a first end of each of a pair of tension springs 136 are secured to respective lower anchor points 138. The other end of each tension spring 136 is secured to a respective upper anchor point 140 formed at the distal end of each of the rails 126 of the upper yoke 122. The tension springs 136 are configured such that they are in tension even when the upper yoke 122 and frame 124 are in this fully contacted position. Therefore, the tension springs 136 constantly apply a resilient biasing force to urge the back plate 102 into its fully contracted position by pulling the rails 126 longitudinally downwards into the channels 132. The minimum length of the back plate 102 (i.e. the maximum contraction of the upper yoke 122 and frame 124) is limited by the fixing portion 128 of the upper yoke 122 contacting the upper edge of the frame 124, which together form a contraction stop mechanism. It should be understood that in other examples, the tension springs 136 may instead be compression springs configured to extend to force the upper yoke 122 into the frame 124. The springs 136 in this example are mechanical springs, but it should be understood that they may alternatively be pneumatic or magnetic springs.

By virtue of the biasing of the back plate 102 to the fully contracted position by the tension springs 136, it will be understood that the back plate 102 will automatically revert to the fully contracted state when it is not being worn by a user. Importantly, SCBAs must often be stored in confined stowing spaces, such as in an emergency services vehicle, so the back plate 102 disclosed herein will advantageously revert automatically to the smallest and easiest stowage configuration without the need for manual adjustment.

When a user is required to don the harness 100, they will do so first by donning the shoulder straps 104,106 and securing the waist belt 108. Once the waist belt 108 is secured, the weight of the harness 100 is predominantly supported by the user’s waist. The shoulder straps 104, 106 of the upper yoke 122 will then be tightened to conform them tightly to the user’s shoulders. This tightening of the shoulder straps 104,106 will move the upper yoke 122 upwardly with respect to the frame 124, counteracting the biasing of the springs 136, and thereby extending the springs 136. The weight of the frame 124 and the waist belt 108 will naturally retain the frame 124 at the user’s waist to thereby ensure that the back plate 102 is extended to the correct length for the user’s comfort. The springs 136 will continuously apply a biasing force which urges the yoke 122 back into the frame 124, but this force is counteracted by the attachment of the upper yoke 122 to the user’s shoulders and the frame 124 to the user’s waist, which sets a minimum length for the back plate 102 during its use.

The harness 100 is shown from the rear in an extended position (such as it would be when secured to many users) in Figure 3. As will be apparent, as the rails 126 of the upper yoke 122 now extend an increased distance from the frame 124, the tension springs 136 have been extended in length. The springs 136 may selected or configured such that they give a substantially constant biasing force across the entire extension range of the back plate 102. Other than the spring biasing force, the rails 126 are freely slidable within the channels 132 between the positions of the maximum and minimum extension. In this example, the back plate 102 cannot be locked’ in any position, but in other examples, such a lock may be provided.

Advantageously, the slidable adjustment and resilient biasing of the back plate 102 permits the back plate length to adjust naturally during use dependent upon the users movements. Thus, it will be appreciated that a secure but flexible fitting of the harness 100 to users of different heights can be achieved without the need for manual adjustment. Generally, the harness 100 having the back plate 102 will automatically adjust to the appropriate length for the user once the shoulder straps 104,106 and waist belt 108 are secured.

Claims

1. A harness for a breathing apparatus comprising:

an adjustable back plate for accommodating a breathing gas delivery system, the back plate being adjustable between a contracted position and an extended position; and a biasing mechanism configured to bias the back plate towards the contracted position.

2. A harness for a breathing apparatus as claimed in claim 1, wherein the back plate comprises an upper back plate element for attachment to at least one shoulder support and a lower back plate element for attachment to a waist support; and wherein the upper and lower back plate elements are moveable relative to each other to adjust the back plate between the contracted position and the extended position.

3. A harness for a breathing apparatus as claimed in claim 1 or 2, wherein the back plate is freely moveable between the contracted and extended positions.

4. A harness as claimed in any preceding claim, further comprising a contraction stop mechanism configured to prevent contraction of the back plate beyond the contracted position.

5. A harness as claimed in any preceding claim, further comprising an extension stop mechanism configured to prevent extension of the back plate beyond the extended position.

6. A harness as claimed in claim 2 or any of claims 3-5 when dependent upon claim 2, wherein the upper and lower back plate elements are movable relative to each other in a longitudinal direction.

7. A harness as claimed in claim 6, wherein the upper and lower back plate elements each comprise complimentary longitudinally-extending features for being slidably engaged to thereby slidably adjust the back plate between the contacted and extended positions.

8. A harness as claimed in claim 6 or 7, wherein at least one of the upper and/or lower back plate element comprises at least one longitudinally-extending rail for being slidably engaged with the other of the upper or lower back plate element to thereby slidably adjust the back plate between the contacted and extended positions.

9. A harness as claimed in any of claims 6-8, wherein the upper back plate element comprises first and second longitudinally-extending rails and the lower back plate element comprises first and second complimentary longitudinally-extending channels for slidably receiving the first and second longitudinally-extending rails of the upper back plate element, the upper back plate element further comprising a laterally-extending shoulder strap fixing portion for attachment to first and second shoulder straps at opposing lateral sides of the upper back plate element.

10. A harness as claimed in any preceding claim, wherein the biasing mechanism comprises a spring element configured to resiliently bias the back plate towards the contracted position.

11. A harness as claimed in claim 10 when dependent upon claim 2, wherein the spring element is configured to be extended by relative movement of the upper and lower back plate elements in the longitudinal direction from the contracted to extended position.

12. A harness as claimed in claim 11, wherein the spring element is configured to be compressed by relative movement of the upper and lower back plate elements in the longitudinal direction from the contracted to extended position.

13. A harness as claimed in claim 2, or any of claims 3-12 when dependent upon claim 2, wherein the upper back plate element is an upper yoke.

14. A harness as claimed in any preceding claim, wherein the breathing gas delivery system is a compressed breathing gas cylinder or a closed-circuit breathing system.

15. A breathing apparatus comprising:

a harness according to any preceding claim;

left and right shoulder straps, an upper end of each shoulder strap being attached to an upper back plate element; and a waist belt attached to a lower back plate element;

wherein relative movement between the upper and lower back plate elements adjusts a distance between the upper ends of the left and right shoulder straps and the waist belt to thereby permit the breathing apparatus to be worn by a plurality of different users having different back lengths without manual adjustment.