Field of the Invention

[01] The present disclosure relates generally to strain relief devices for neckbands (such as a lanyard) - i.e., devices that offer anti-strangle relief functionality to mitigate the possibility of harm to a neckband wearer by breaking open above a certain force - and more specifically to genderless safety links used to form a safety fastener and methods of manufacture of such links. Moreover, the present disclosure is particularly concerned with strain relief fasteners (and safety links thereof) for use on lanyards in the social care sector.

Background

[02] In social care environments, it is common for a client (i.e., a person being cared for, such as an elderly patient) to be issued with a device by which they can contact an onsite or remote care operator. These social alarm devices I alarm triggers I trigger devices, oftentimes have additional functionality built in such as fall detecting. To ensure that such alarm devices are always carried by the client, it is common for them to be worn on a neckband (e.g., a lanyard).

[03] It has long been appreciated in many industries that a neckband presents a possibility of harm to the wearer from e.g., the band getting caught on an object. This is particularly the case in social care environments, where a wearer might have physical difficulties which prevent them from otherwise removing a caught band. As such it is desirable that neckbands/lanyards in social care environments are provided with an anti-strangle mechanism (also termed a strain relief device) which breaks apart when subjected to a certain force.

[04] In the UK, the current standard for strain relief devices for social alarm neckbands is provided by BS EN 50134-2 (current version 2018) which, inter alia, specifies that strain relief devices must not break at forces at or below 25 N (Newtons), and must break at forces at or above 40 N (this aspect dates back to the 2000 version of the standard, i.e., BS EN 50134- 2:2000).

[05] Existing strain relief devices in use in social care environments (and which purport to meet this standard) are exemplified by Figure 1 . Such designs include a male connector end (/insertion end) and a female connector end (/receiver end), each end comprising compatible mating ‘bump off’ features (so called due to how they are formed in a mould) in the form of a circular protruding ring (male end) and circular recessed ring (female end). Insertion of the male connector end into the female connector end suitably engages these bump off features

[06] An issue with these designs, however, is that they are incredibly unreliable. A deviation of less than 0.1 mm (millimetres) in the mating ring aspects (which can arise from e.g., demoulding during the manufacturing process) can cause large deviations in the retention force of the strain relief device. For example, on average, only around 66% of the manufactured strain relief devices shown in Fig. 1 satisfy the retention force limits (i.e., never breaking at or below 25 N, always breaking above 40 N). This obviously leads to a great deal of manufacturing waste, and indeed wasted time having to suitably stress test each strain relief device before putting it into service.

[07] Hence it is highly desirable to develop an improved strain relief device as an alternative to previously available designs.

Summary

[08] The present invention is defined according to the independent claims. Additional features will be appreciated from the dependent claims and the description herein. Any embodiments which are described but which do not fall within the scope of the claims are to be interpreted merely as examples useful for a better understanding of the invention.

[09] The example embodiments have been provided with a view to addressing at least some of the difficulties that are encountered with current strain relief devices used in social care settings, whether those difficulties have been specifically mentioned above or will otherwise be appreciated from the discussion herein.

[10] Suitably, in one aspect of the invention there is provided a strain relief device for a neckband formed from a pair of genderless safety links. Each of the pair of genderless safety links are substantially identical and comprises a body comprising first engagement means, and a member, extending from a first end of the body, comprising second engagement means; the first engagement means and second engagement means of a genderless safety link are arranged rotationally out of phase with each other with respect to a major central axis of the body. To form the strain relief device, the first engagement means of each genderless safety link is configured to mutually cooperate with the second engagement means of each genderless safety link to detachably couple the member of each genderless safety link to the body of the other genderless safety link. In a preferred example, coupling the genderless safety links includes inserting the members of each safety link into a cavity formed in the body of the other safety link.

[11 ] The member is a first one of a set of members comprising at least two members, the first engagement means is a first one of a set of first engagement means comprising at least two first engagement means, and the second engagement means is a first one of a set of second engagement means comprising at least two second engagement means. Each one of the set of second engagement means is provided on a respective one of the set of members, and cooperates with a respective one of the first engagement means. Suitably it may be considered that the entire set of first engagement means is rotationally out of phase with the entire set of second engagement means.

[12] Advantageously, forming the first and second engagement means rotationally out of phase allows for the genderless safety link to be formed following principles for line of draw moulding. That is, the first and second engagement means are configured to slidably align with a line of tool draw (of a moulding tool used to form a genderless safety link). Put another way, the genderless safety links (and, specifically, the first and second engagement means) do not comprise any undercut features (sometimes termed bump off features). Also, rotationally misaligning the first and second engagement means ensures that the safety links cannot themselves rotate with respect to one another when linked to form the strain relief device, reducing a rate of wear on the device and thereby improving durability.

[13] Preferably, the pair of genderless safety links are configured to decouple at loads greater than 25 N, and less than or equal to 40 N, so that the strain relief device is suitable for use in social care environments as per BS EN 50134-2. Other decoupling loads may be appropriate in different industries. Suitably, the present invention also relates to the use of the aforementioned strain relief device with a neckband carrying a social alarm trigger device.

[14] In an example where the set of members comprises exactly two members, a bisecting plane coincident with the line of tool draw is equidistant from each member, with the members and associated second coupling means being preferably parallel. Two members has been determined to have advantageous properties for design of the members and coupling means to achieve the desired break properties (e.g., 25-40 N load) while allowing for simplicity of manufacture and convenience of use by a (typically elderly) client.

[15] In a related aspect of the invention there is provided a (singular) genderless safety link for use in a strain relief device for fastening a neckband (in a social care environment). The safety link comprises a body comprising first coupling (engagement) means, and a member, extending from a first end of the body, comprising second coupling (engagement) means, wherein the first coupling means and second coupling means are configured to mutually cooperate, and wherein the first coupling means and second coupling means are arranged rotationally out of phase with respect to a central major axis of the body. Suitably, the genderless safety link does not comprise any undercut features with respect to a plane bisecting the genderless safety link -that is, aspects of the genderless safety link, and especially the coupling means, may be considered to slidably align with this bisection plane; the bisecting plane being one which aligned with the direction of the line of tool draw.

[16] The first coupling means and second coupling means are rotated between 60 degrees and 180 degrees out of phase with each other, depending on a rotational symmetry of the genderless safety link (the rotational symmetry being largely defined by a number of members of the link: e.g., 180 degrees in the case of one member, 60 degrees in the case of three members, and in the preferred case of two members, 90 degrees out of phase).

[17] Suitably, the member is a first one of a set of members comprising at least two members, the first coupling means is a first one of a set of first coupling means, and the second coupling means is a first one of a set of second coupling means. A total number of first coupling means in the set of first coupling means, and a total number of second coupling means in the set of second coupling means, is preferably equal to the total number of members in the set of members. Preferably the set of members comprises two members, and in such a case the bisecting plane coincident with the line of tool draw is equidistant from each member, with the members and associated second coupling means being preferably parallel. Two members has been determined to have advantageous properties for design of the members and coupling means to achieve the desired break properties (e.g., 25-40 N load) while allowing for simplicity of manufacture and convenience of use by a (typically elderly) client.

[18] In one example, the second coupling means comprises a male mating part, while the second engagement means comprises a corresponding female mating part. Desirably, the first and second coupling means may be configured to engage in a substantially linear fashion. To this end, the male mating part may comprise a substantially elongate protuberance protruding from the member, while the female mating part comprises a correspondingly shaped opening in the body.

[19] In another aspect of the invention there is provided a tool for moulding an aforementioned genderless safety link for a strain relief device. The tool comprises a first tool part comprising a first surface with a first recess, and a second tool part comprising a second surface with a second recess. The first recess and second recess are configured to, in combination (when the tool parts are brought into abutment with the first/second surface touching) shape at least part of a body, at least part of a member, at least part of a first engagement means, and at least part of a second engagement means of the genderless safety link. Suitably the recesses are configured to shape the first engagement means and second engagement means rotationally out of phase with respect to a major central axis of the body, and the first and second recesses comprise surfaces which are configured to slidably align with a line of draw of the moulding tool; in this way no force/pressure is exerted on the genderless safety link when it is demoulded. It will be appreciated that, as per typical moulds, the first and second recesses therefore shape an outer surface of the genderless safety link.

[20] Preferably the first tool part and second tool part are symmetric across the first and second surface, although non-symmetric tool parts may be employed, depending particularly on the rotational symmetry desired from the end product safety link.

[21] In one example, the first and second recesses are configured to, in combination, shape the second engagement means as an elongate structure with major axis substantially perpendicular to a line of moulding of the tool. Correspondingly, the first and second recesses may be configured to shape the first engagement means as an opening through the body of the genderless safety link.

[22] In some examples the tool further comprises a third tool part which is configured as an insert for a cavity formed by the first and second recess in combination, by which an internal cavity (and appropriate internal surfaces) of a genderless safety link may be formed. Similar to the first and second recesses, the surfaces of the third tool part slidably align with its line of tool draw; i.e., the direction by which it is inserted into the moulding cavity formed by the first and second recess, and withdrawn from the cavity formed in the genderless safety link by the third tool part, so that there are no forces generated on the genderless safety link while the third tool part is removed.

[23] Relatedly, in one aspect of the invention there is also provided a method of manufacture of a genderless safety link using the aforementioned moulding tool. The method comprises arranging the first tool part and second tool part with first and second faces abutting by moving the parts towards each other along the line of tool draw, optionally inserting the third tool part into the moulding cavity formed by the recesses of the first and second tool part (the cavity corresponding to a shape of the genderless safety link being formed), injecting a moulding agent into the moulding cavity formed by the first recess, second recess, and surfaces of the third tool part, and, afterthe mould has set, separating the first and second tool parts by moving them apart along the line of tool draw.

[24] Preferably the moulding agent is a material which is hydrophobic when set, so that the resulting genderless safety link can be safely used in environments of high humidity or where water is present (e.g., in the shower). Further preferably the moulding agent is a thermoplastic polymer, and yet further preferably the moulding agent is at least one of Acrylonitrile butadiene styrene (ABS) and Polypropylene.

Brief Description of the Drawings

[25] For a better understanding of the present disclosure reference will now be made by way of example only to the accompanying drawings, in which:

[26] Fig. 1 shows an example strain relief device known in the art;

[27] Fig. 2 shows an example improved strain relief device as part of a lanyard (neckband) for a trigger device;

[28] Fig. 3 shows a pair of genderless safety links used to form the example improved strain relief device, pre-engagement;

[29] Fig. 4 shows the example improved strain relief device when the genderless safety links are engaged;

[30] Fig. 5 shows a cut through the (engaged) example improved strain relief device;

[31] Fig. 6 shows break force test results from first (Fig. 6A) and second (Fig. 6B) prototype batches, and lifetime for an example improved strain relief device (Fig. 6C);

[32] Fig. 7 shows an example tool for forming an example strain relief device;

[33] Fig. 8 shows a method of manufacture incorporating the tool of Fig. 7; [34] Fig. 9 shows another example strain relief device when its genderless safety links are engaged; and

[35] Fig. 10 shows separate views of an individual safety link of the strain relief device of Fig. 9.

[36] In these figures and the following, reference numerals are shared for common features of the genderless safety links, but prime notation ( ‘ ) is used to distinguish aspects of one link from the otherwhere appropriate).

Detailed Description

[37] At least some of the following example embodiments provide for an improved neckband strain relief device. The example device demonstrates many improvements for a more robust strain relief device that is both convenient in use and in manufacture. Many other advantages and improvements will be discussed in more detail herein.

[38] With reference to Figures 2 to 5, there is shown an example strain relief device 10 for securing a neckband 12 which holds an alarm device 14. The alarm device 14 is envisaged as any suitable device used in a social care environment, for example an electronic alarm trigger or fall detector, although it will be appreciated that the disclosure is not limited thereto and the strain relief 10 of the present disclosure may be suitably used on neckbands carrying any suitably lightweight load.

[39] The strain relief device 10 is formed from a pair of interlocking genderless (or hermaphroditic) safety links 100 1 100’. That is, the genderless safety links 100 are manufactured to be substantially identical in shape in size, such that there is no dedicated male end or female to the strain relief device 10. It will be readily appreciated that genderless design has many advantages for manufacture and ease of use. Moreover, although hermaphroditic clips may be used in other sectors, there are no known designs which conform to current standard on social care neckbands.

[40] Suitably the genderless safety links 100 interlock detachably in order to satisfy the requirement that the safety links 100 separate under a suitably heavy load (e.g., when the neckband gets caught on an object). The safety links 100 described in the present disclosure are preferably arranged (i.e., shaped I dimensioned) to meet the retention/break requirements of BS EN 50134-2 - i.e., breaking at loads at or above 40 N, retaining the link at loads below that and never breaking below 25 N (at least on initial testing) - however it will also be appreciated that the teachings herein may be readily adapted to meet other retention standards as may be required by other industries.

[41] In general, each genderless safety link 100 comprises a body 102, a member 104 extending from a first end 106 of the body 102, and mutually cooperative engagement means configured to detachably couple the member 104 of one of genderless safety link 100 to the body 102’ of the other genderless safety link 100’. More specifically, the mutually cooperative engagement means are configured to fasten together the strain relief device when the first ends 106, 106’ of the pair of links 100, 100’ are brought into abutment with each other.

[42] In the present, preferred, example it should be apparent that each genderless safety link 100 comprises two members, or tangs, 104 configured to couple to the body 102. Put another way, each genderless safety link 100 comprises a set of members 104, with the set of members in the present example comprising a first member 104a and a second member 104b. In this preferred example the tangs 104 are formed identically to each other, and so only the function of one member is described except where appropriately discussed separately. It should be appreciated, however, that the disclosure is not limited thereto and genderless safety links with only one tang, or a set of three or more tangs, are also within the present scope, as are tangs which are not formed identically (e.g., one shorter than the other, although this is not preferred).

[43] Suitably, the mutually cooperative engagement means comprise corresponding mating (i.e., detachably coupling) parts. A first mating part (/coupling means) 108 is provided on the member 104, with a correspondingly opposite second mating part (/coupling means) 110 being provided on the body 102. Put another way, the second mating part 110 is designed to detachably couple to the first mating part 108 even though the first and second mating parts 108, 110 are provided on the same safety link 100 (and it will be appreciated that in use the mating parts of a single link will never engage with each other). Thus, when the strain relief device 10 is fastened together, the first mating part 108 of the first genderless safety link 100 detachably couples to the second mating part 110’ of the second genderless safety link 100’.

[44] Where there is provided a set of members, or tangs, 104 (as shown) each genderless safety link may be considered to comprise a corresponding set of first coupling means 108 and a set of second coupling means 110. For example, in the preferred embodiment of the set of members comprising two members, the set of first coupling means 108 includes one first mating part 108a on the first member 104a of the set of members 104, and another first mating part 108b on the second member 104b of the set of members 104, while the set of second coupling means 110 includes one second mating part 110a (on the body 102) corresponding to the first mating part 108a in the first set of coupling means 108, and another second mating part 110b corresponding to the other first mating part 108b of the first set of coupling means 108. It should be appreciated however that in other examples (not shown), the set of first coupling means may comprise at least one mating part of its set on one of the set of members, and at least one other mating part of its set on the body, while correspondingly the set of second coupling means may comprise at least one second mating part on one of the set of members 104, and at least one second mating part on the body 102.

[45] Suitably, the first mating part 108 and second mating part 1 10 are arranged rotationally out of phase with one another. More specifically, at least the mechanical features of the mating parts by which the member 104 couples to the body 102 are rotated with respect to one another. Suitably the first mating part 108 and second part 110 of opposing links in the strain relief device 10 must be rotationally aligned with each other in order for the genderless safety links 100 to couple. Put another way, the mating parts 108, 100 do not themselves have rotational freedom, so that they can only be engaged with each other if coupled from a predefined angular direction. Suitably, the first mating part 108 and second mating part 1 10 are arranged such that there is no overlap of the mating parts in the plane of the out of phase rotation - i.e., the mating parts 108, 110 do not visibly overlap when a genderless safety link is viewed orthogonal to that plane, e.g., when viewed along the direction of engagement.

[46] Preferably the (out of phase) rotation is with respect to a central axis of the genderless safety link 100 which is colinear (i.e., pointing) with the direction of engagement. More generally, the out of phase rotation may be with respect to a major axis, which may be considered as an axis passing through a centre of mass of the body and pointing in the direction of engagement, and which preferably coincides with a longest dimension of the body 102. Put another way, the out of phase rotation of the mating parts is with respect the major central axis of the fastened strain relief device 10. Suitably, in the present example whereby the body 102 is substantially cylindrical - or at least elongate in shape - and the strain relief device when fastened similarly cylindrical/elongate, then the central axis is that in a z direction running along the middle of the genderless safety link 100’s I strain relief device 10’s longest dimension (and consistent with cylindrical coordinates, being orthogonal in direction to an r, theta plane).

[47] Suitably, it can be seen that in the presently preferred example with two members 104a,b, that each member (and more specifically, the mating part 108 thereof) is rotated by 90 degrees with respect to the second mating part 110 provided on the body 102. In other examples, not shown, the out of phase rotation may be suitably different. For example, with a single member, the rotation of member with respect to corresponding mating part on the body may be 180 degrees, while with three members, the rotation with respect to corresponding mating parts on the body (of which there would be three) may be 60 degrees.

[48] This out of phase alignment of the mutually corresponding mating parts 108, 1 10 provides significant advantages over existing strain relief devices. An inability of the fastened strain relief device 10 to rotate after it is fastened prevents unintended wear that can arise in prior art systems from slippage of the male and female ends, while preferably the symmetric nature of the set of members allows for ease of engagement of the pair of genderless safety links 100 forming the strain relief device 10 by rotation either clockwise or anti-clockwise with respect to each other (i.e., when their respective first ends 106 are aligned parallel with each other). In an example where the set of tangs are not symmetric (either in dimensions or mating parts provided thereon), the strain relief device would still retain the advantage of less wear, but would instead require a set rotation direction; this is generally not preferred for social care clients who desire simplicity in their devices, but may be appropriate if for use of the strain relief device in some other industries. [49] Moreover, rotating the mating parts 108, 110 with respect to each other opens up beneficial opportunities to manufacture the genderless safety links using line of draw moulding. Line of draw moulding is a (moulding) technique in which aspects of the object being moulded are substantially aligned with a direction in which a moulding tool (or part thereof) moves when extracting the object from the mould. That is, the object being moulded, which here is a genderless safety link 100, does not comprise any undercut, or bump off, features; such features would otherwise require the tool and/or the object to at least partly deform in a different direction to the line of draw, which causes stresses on the object which can impact its performance. Notably, the ring like male/female engagement features of prior art strain relief devices are historically manufactured using ‘bump off’ moulds, which leads to a high number of defective strain devices which do not pass quality control.

[50] Suitably, other aspects of the genderless safety link 100 may also be designed with line of draw moulding in mind. For the examples shown in Figs 2-5, the line of draw is along a plane bisecting the genderless safety link 100 along its major (elongate) axis, in between the two members 104a, b, and so through the second mating parts 110a,b; this will become more apparent when manufacturing is suitably discussed later herein. Put another way, the line of draw is a direction orthogonal to a plane defined by a mould line 112 for the genderless safety links 100.

[51] Preferably, in the present example the pair of members 104a,b are arranged parallel to each other. Accordingly, the first mating parts 108a,b of each member 104a,b are antiparallel to each other: that is, the respective first mating parts 108a,b are substantially aligned parallel to the same plane as the members 104a,b, but pointing in opposite directions to each other. Suitably, in the present examples the first mating part 108 is a male (or insertion type) mating part.

[52] More specifically, the first mating part 108 comprises a protrusion, protuberance, re-entrant feature, or similar, extending substantially orthogonal to the member 104. In the shown preferred example the first mating part 108 protrudes outward from the central axis of the genderless safety link 100. That is, the first mating part 108a extends away from its member 104a in a direction away from the other member 104b and its corresponding first mating part 108b.

[53] Preferably, the first mating part 108 is configured to be substantially linear in its axis which is colinear with the line of draw; this makes configuring a tool for moulding substantially easier. Put another way, the first (male) mating part 108 is substantially elongate, or cylindrical, with its longest major dimension (i.e., it’s z direction in standard cylindrical coordinate system) being the dimension which is substantially linear in the direction of the line of draw.

[54] In some examples the first mating part 108, and indeed the member 104, may be formed with a tapered shape provided that the taper does not interfere with the line of draw. More specifically, in the present example the member 104 and first mating part 108 may taper from a point on its surface corresponding to greatest mass (e.g., the centre of the member 104 and/or first mating part 108), which will generally be at the mould line 1 12, towards the centre line of the genderless safety link 100 (or put another way, toward a point on a plane bisecting the genderless safety link 100).

[55] Accordingly, in the present examples the second mating part 110 is a female (or receiving type) mating part configured to receive the first (male) mating part 108. Suitably the second mating part 110 (of which there are, of course, two in the present example, 110a,b) may be formed as an opening, a recess, a hole, or similar, suitably dimensioned to receive and retain the protrusion of the first mating part 108.

[56] In the preferred example as shown, the body 102 comprises a cavity 114 into which may be received the member(s) 104 and first mating part(s) 108 from the other genderless safety link 100’; put another way, the member(s) 104 and first mating part(s) 108 are configured to insert into the body 102’ of the other genderless safety link 100’. Suitably, the second mating part(s) 110 are configured as an opening through the body 102 from the body’s outer surface to the cavity 114. In this way line of draw moulding is made easier (as it would otherwise be more complicated, and so less economical, to form an internal recess in the cavity 114 of the body 102 without using bump off moulding. In keeping with the line of draw design, internal surfaces of the body 102 - i.e., the surfaces of the cavity 114 - are either all linearly parallel between the first end 106 and the opposite, second, end 116 of the genderless safety link 100, or taper outwardly from the second end 116 towards the first end 106.

[57] Suitably, there are a number of design parameters to consider to achieve the desired functionality of the strain relief device 10 - that is, the fastening and decoupling behaviour of the genderless safety links 100.

[58] One parameter is a length of the member 104; more specifically, a distance from the first end 106 of the body 102 to a centre of the first mating part 108 (e.g., its centre of mass in the case of a protrusion). A longer distance will generally reduce a release force required to disengage coupled mating parts 108, 110, and conversely a shorter distance increases the required release force.

[59] That is, the length of the tang (/member) 104 has an inversely proportional relationship to the force the tang exerts normally to the tang axis. This can be seen from the following formula for calculating the deflection of the member 104: where P is the deflection force, L is the length of the tang, 6 _max is the maximum tang deflection, E is elastic modulus, and I is moment of inertia (the equation can of course be suitable rearranged for deflection force P). Here, the elastic modulus (E), moment of inertia (I) and tang deflection (6_max) can be treated as constant if the same material, tang 104 cross section geometry, and protrusion geometry (which may also be termed tang ‘tooth’ geometry) are used respectively. The deflection force (P) has a direct relationship to the retention force of the strain relief device 100 and can be modified at the design stage to enable the retention force to be within design requirement limits (e.g., 25 N to 40 N).

[60] Similarly, for a desired length of tang 104, the other variables can be modified to adjust the retention force: e.g., choosing a material with a higher elastic modulus, or increasing the cross sectional area of the tang (i.e., its thickness), will result in an increase in tang deflection force and thus an increase in the retention force of the assembly.

[61] Relatedly, a size of the male aspect 108 (i.e., tang tooth) of the mutual mating parts 108, 110 in the direction in which it engages the corresponding female aspect - for example, the amount by which the protrusion 108 emanates from the surface of the member 104 - also informs the tang behaviour. The size of the protrusions suitably determines how much the member 104 has to bend before the mating parts 108, 110 decouple.

[62] Somewhat surprisingly, a distance between the members 104 (when there is a set of members) has been determined to not greatly impact the device tolerance, instead being largely a function of choice of body size (which will be at least partly determined by the considerations above, but also others such as material, intended usage, and so on).

[63] As discussed above, the present embodiments are designed in order to fit the parameters of a breaking (i.e., decoupling force) being between 25 N and 40 N. Example parameters of the genderless safety link 100 which achieve that goal are indicated in Table 1 (along with example parameters that don’t). In particular it can be seen that a material with elastic modulus 4800 MPa and tang length of 5mm yields an average retention force (when assembled) in the desired window (25N-40N), while other tang lengths may be suitable for other purposes. In general, it is preferable for each tang/member 104 to be between 4.5 mm and 5.5 mm in length.

TABLE 1 - Retention forces of links using preferred embodiment member and tang protuberance geometry and material E=4800 MPa (Ramofin PPH300G4)

[64] Figure 6 shows test results from two separate manufacturing batches of the presently preferred genderless safety links (4800 MPa elastic modules, 5 mm tang length) - Figs. 6A and 6B - where it can be seen that 100% of the strain relief devices resulted in a break force in the desired range of 25 to 40 N. Moreover, even with slight manufacturing differences, it can be seen that the tolerance in break force is much reduced over prior art devices. That is, in Fig. 6A the break force ranges by 8 N, whereas in Fig. 6B the break force ranges by 9 N.

[65] Moreover, as shown in Fig. 6C, testing has revealed that strain relief devices manufactured according to the present disclosure maintain functionality within the desired break range (25 N to 40 N) for approximately 200 activations (i.e., breaks) before some devices begin to show signs of structural weakening (which result in strain relief device separation below the desired 25 N lower limit). It should be noted however that a number of successful tests is not within the British standard but far surpasses prior art strain relief devices, and also a lifetime of approximately 200 uses is generally considered more than sufficient given that the neckband in social care environments is not usually sized to require the strain relief device to disengage in orderto remove it, but to simply slip over a user’s head when not required.

[66] It will be appreciated that other parameters may be suitable for achieving different break tolerances which may be useful to industries beyond social care. For example a lower material elastic modulus of 1150MPa combined with a 5mm tang length or tang length of 8mm combined with a material elastic modulus of 4800MPa would achieve a break force of ~12-14N. This could be useful in an application where a lower retention force is desirable than required in the preferred embodiment.

[67] It will also be appreciated that other arrangements of the genderless safety link 100 are also within the scope of the invention. For example, as shown in Figures 9 & 10, the member 104 may be suitably arranged to reside external to the body 102, rather than insert into the cavity 114, so that the mating parts 108, 110 engage from the outside of the body 102; that is, the members 104 may be arranged to engage the body 102 in a claw like fashion (and it will be appreciated that in such an example more than one member would be a requirement, whereas an insertion arrangement allows for single member safety links if desired). In this example the body 102 may also comprise a groove 120 to accommodate the member 104, so that the outer surface of the member 104 lies flush with the outer surface of the body 102 when the pair genderless safety links 100 are coupled.

[68] Furthermore, it will be appreciated that the genderless safety link 100 comprises means 118 for securing the genderless safety link 100 to an end of the neckband 12. In the present example such means are an opening in a second end 116 of the body 102, opposite the first end 106. The opening is suitably dimensioned to be slightly larger than a diameter of the neckband 12. This allows for the end of the neckband 12 to be inserted through the opening into the cavity 114, pulled through the first end 106 and suitably tied in a knot; the knot then residing in the cavity 114 and pulling against the body 102 around the inside of the opening 118, thereby securing the neckband 12 to the genderless safety link 12. [69] While the demonstrated means for securing the neckband 12 are desirable and advantageously simple for the shown preferred embodiment of the strain relief device 10, it will be appreciated that other means for securing the neckband 12 to a genderless safety link 100 may be employed depending on the specific configuration of the genderless safety link 100. For example, the means 118 may instead be in the form of a ring attached on an outside of the body 102, possibly at the second end 118; the neckband 12 then being tied to the ring. Other examples may also be possible.

[70] Figure 7 shows an example tool 200 which may be used to manufacture a genderless safety link 100 by injection moulding. Generally, the genderless safety links 100 for the strain relief device 10 may be manufactured from any plastic (or other material) suitable for use in an injection moulding technique. Also, the chosen material is preferably hydrophobic so that the strain relief is not effected by e.g., use in a shower or bath. Suitably the manufacturing material may be a thermoplastic polymer, which is preferably one of Acrylonitrile butadiene styrene (ABS) or Polypropylene.

[71] The tool 200 is formed from at least two parts (basically halves) 202, 204, which each respectively comprise a recess arranged to, in combination with the recess from the other part, define an outer surface shape of the genderless safety link 100. Thus, the two parts 202, 204 of the tool 200, when joined, define a cavity 203 in the (joined) tool into which may be injected moulding agent, thereby forming the shape of the genderless safety link 100. The moulding line 112 seen on the genderless safety link 100 is accordingly a result of the moulding using the at least two tool parts 202, 204. In preferred examples the tool also comprises a third tool part 206 which is configured as an insert for the cavity 203 so as to shape the internal surfaces of the genderless safety link 100, allowing for the formation of the cavity 114 and the empty space in between the members 104a,b; although it will be appreciated that, depending on the exact safety link configuration, a third part 206 may not be necessary.

[72] More specifically, the first tool part 202 comprises a first surface 208 comprising a first recess 210 configured to shape a first part (preferably half) of the safety link 100. The first part of the safety link 100 so shaped includes at least part of the body 102 and at least part of the member 104. Suitably, the first recess 210 will shape at least part of the first mating means 108 and at least part of the second mating means 110. In the present example, it can be seen that the recess 210 of the preferred tool shapes half of the body 102, half of the members 104a,b, half of the first mating means 108a,b, and a first one of the second mating means 110a (by being provided with a suitable inset to shape an opening).

[73] The second tool part 204 similarly comprises a second surface 212 comprising a recess 214 configured to shape a second, remaining, part (preferably half), of the genderless safety link 100. Suitably the shaped second part of the safety link 100 includes a remaining part of the body 102 and a remaining part of the member 104 (i.e., completing the features of the genderless safety link 100). Suitably the second recess 214 will also shape a remaining part of the first mating means 108 and a remaining part the second mating means 110. In the preferred example shown in the Figures, the recess 214 shapes the second half of the body 102, second half of the members 104a, b with second half of the first mating means 108a,b, and a second one of the second mating means 110b (again by being provided with a suitable inset to shape an opening).

[74] It will be readily appreciated that in the preferred example shown herein the first tool part 202 and second tool part 204 are mirror images of each other, being configured to suitably mould a respective half of the genderless safety link 100.

[75] As per the desire for line of draw moulding, the first and second tool parts 202, 204 are configured so as to not comprise any undercut features that would require ‘bump off moulding. Suitably, all features of the recess(es) are configured to slidably align I cooperate with the line of draw, by e.g., tapering inward into the body of the first tool part 202 and second tool part 204, respectively. That is, interior surfaces of the first recess 210 of the first tool part 202 are either perpendicular to the first surface 208, parallel to the first surface 208, or are at an obtuse angle (on the interior, i.e., cavity forming, side of the recess) to any plane parallel to the first surface. In this way all surfaces of the first recess 210 are visible when viewing the tool orthogonal to the first surface 208. Suitably the second tool part 204 is likewise configured so that the interior surfaces of the second recess 214 are either perpendicular to the second surface 212, parallel to the second surface 212, or taper inward and so are at an obtuse angle (on the interior, i.e., cavity forming, side of the recess) to any plane parallel to the second surface 212. In this way all features of the genderless safety link may be formed in cooperation with the line of draw of the tool 200.

[76] Suitably, in the preferred example, the first tool part 202 is configured to shape its parts of the first mating features 108 as a substantially linear elongate structures aligned perpendicular to the first surface 208, and the second tool part 204 is configured to shape its remaining parts of the first mating features 108 also as a substantially linear elongate structures aligned perpendicular to the second surface 212. In this way the first mating parts 108 especially are ensured to be aligned with the line of draw of the tool, ensuring that the first mating parts do not get deformed when demoulding. Accordingly, each of the first tool part 202 and second tool part 204 are configured to form a substantially elongate opening hole in the body 202 as the second mating part 110, each second mating part 110 being arranged 90 degrees out of phase with the first mating parts (and at a suitably configured position based on the length of the members 104). Appropriately, insets 216 in the respective recesses 210, 214 used to form the openings 110 are also cooperative with the line of draw of the tool parts 202, 204.

[77] In another example, where only a single member 104, single first mating part 108, and single second mating part 110 are provided, the first tool part 202 and second tool part 204 may be configured to each form part of the (sole) second mating part 110. That is, each tool part 202, 204 forms at least part of the first mating part 108 and at least part of the second mating part 110. As with the first mating part 108, an aspect of the respective tool parts 202, 204 configured to shape the second mating part (i.e., a respective part of the recesses 210, 214) may be configured to be cooperative with the line of draw of the tool.

[78] In more complex examples, with more than two members, and so correspondingly more than two pairs of mutually cooperative mating means are provided, then a more complex tool may be required depending on the rotational symmetry of the genderless safety link. For example, where the genderless safety link has three members and so triangular rotational symmetry, then it may be desirable to provide three tool parts to form the outer surface of the genderless safety link, the line of draw of each tool part being along a different radial direction to each other tool part, and so appropriately each tool part forming at least part of two members (and associated first mating parts) and a complete second mating part in the body of the genderless safety link.

[79] Suitably, a method of manufacture of a genderless safety link, using an example tool, may be as shown in Figure 8.

[80] At step 802 the first tool part 202 and second tool 204 are arranged with first surface 208 and second surface 212 abutting in order to form the moulding cavity 203. Suitably the surfaces may be brought into abutment by moving he first and second tool parts towards each other along their respective lines of draw (which, in the present case, are coincident, being vertically up and down on the page as per Fig. 7).

[81] Optionally, depending on the specific design of the final genderless safety link, at step 804 the third tool part 206 is inserted into the moulding cavity 203. The third tool part 206 may be suitably configured to act as a plug for moulding cavity 203.

[82] At step 806, moulding agent, such as a molten thermoplastic, is injected into the cavity 203. Injection may be via one or more suitable paths (not shown) provided in one or a combination of the first tool part 202, second tool part 204, and third tool part 206.

[83] At step 808 the moulding agent is allowed to cool, which sets the moulding agent by changing it from a molten to solid state.

[84] At step 810, the first, second, and if present third, tool parts are pulled apart from each other along their respective lines of draw (i.e., the genderless safety link 100 is demoulded). That is, in the example of Fig. 7, the first and second tool parts 202, 204 are pulled apart from each other in a vertical line, while the third tool part is pulled out of the cavity 114 of the genderless safety link 100, its line of draw being perpendicular to the shared line of draw of the first and second tool parts 202, 204.

[85] In summary, exemplary embodiments of an improved strain relief device formed from a pair of genderless safety links have been described, along with exemplary embodiments of methods of manufacture and associated tooling. It will be appreciated that the described exemplary embodiments provide for a strain relief device with enhanced performance compared to prior art models.

[86] The genderless safety links and the strain relief device may be manufactured industrially. An industrial application of the example embodiments will be clear from the discussion herein. Additionally, the described exemplary embodiments are convenient to manufacture and straightforward to use.

[87] Although preferred embodiments) of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes may be made without departing from the scope of the invention as defined in the claims.

[88] Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

[89] All of the features disclosed in this specification, and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

[90] Each feature disclosed in this specification may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

[91] The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification, or to any novel one, or any novel combination, of the steps of any method or process so disclosed.