AU2013204783B2

AU2013204783B2 - Safety chain attachment

Info

Publication number: AU2013204783B2
Application number: AU2013204783A
Authority: AU
Inventors: Wayne Baker; Allan Bartlett
Original assignee: BARTLETT TRANSP IMPROVEMENTS Pty Ltd
Current assignee: BARTLETT TRANSPORT IMPROVEMENTS PTY Ltd
Priority date: 2013-04-12
Filing date: 2013-04-12
Publication date: 2016-08-04
Anticipated expiration: 2033-04-12
Also published as: AU2013204783A1

Abstract

A safety chain attachment device for use with a safety chain having a plurality of links, the links including a leading link and a following link connected to the leading link, the device 5 including: a clevis having first and second sides and an aperture passing between the first and second sides; and a clevis pin receivable in the aperture to tether the leading link to the clevis; wherein the clevis includes, between said first and second sides, a seating region which is contoured to accommodate at least a surface geometry of the leading link, such that a clearance between the clevis and the leading link is minimised when the clevis pin is received 0 in the aperture. -42 FIGURE 1 34 24 50 O r-10 - 12

Description

SAFETY CHAIN ATTACHMENT

The present invention relates to a safety chain attachment, for example for use in prevention of separation of a trailer from a towing vehicle in the event of accidental decoupling.

In order for a powered vehicle to tow an unpowered vehicle such as a trailer it is necessary to provide a mechanical connection between the vehicles. Due to the occasional in-service failure of mechanical couplings it is desirable to use a secondary means of retaining the trailer for fail-safe purposes. Regulations (such as Australian Design Rule 62) typically prescribe that some form of safety device, for example safety chains or cables, be used to attach the towed vehicle to the towing vehicle to ensure it is properly supported in the event of an accidental decoupling. Regardless of regulatory requirements, it is critically important to ensure a safe connection between vehicles in order to protect the vehicles, other road users, and the community.

One known means of attaching safety chains to a trailer is to provide an attachment member including a clevis and a clevis pin. The attachment member is affixed to the trailer by welding and the clevis pin is used to secure a link of the safety chain.

According to a first aspect of the present invention, there is provided an attachment for use with a safety chain having a leading link and a following link connected to the leading link, the attachment being configured with a mount, via which it is secured or securable against a support surface, and comprising a clevis having first and second lateral side sections and an opening, between the sections, into which a leading end of the leading link is receivable, the sections being arranged to receive a pin member such that the pin member extends across the opening to couple the leading link to the clevis when the leading end is received in the opening, wherein a portion of the clevis defined between the sections has a configuration complementary to a configuration of the leading end of the leading link in a plane perpendicular to an axis of the pin member, whereby, when the leading link is coupled to the clevis by the pin member, there is maintained a close fit between the clevis and chain as the leading link and following link rotate relative to the clevis about the axis of the pin member.

According to a second aspect of the present invention, there is provided an attachment for use with a safety chain having a leading link and a following link connected to the leading link, the attachment being configured with a mount, via which it is secured or securable against a support surface, and comprising a clevis having first and second lateral side sections and an opening, between the sections, into which a leading end of the leading link is receivable, the sections being arranged to receive a pin member such that the pin member extends across the opening to couple the leading link to the clevis when the leading end is received in the opening, wherein portions of the sections have configurations complementary to a configurations of a leading end of the following link, whereby, when the leading link is coupled to the clevis by the pin member, there is maintained a close fit between the clevis and chain as the leading link and following link rotate relative to the clevis about an axis of the pin member.

According to a third aspect of the present invention, there is provided an assembly comprising: an attachment according to the first or second aspect; said pin member; and said chain, wherein the pin member is received by the first and second side sections, so as to extend across the opening, and the leading end of the leading link is received in the opening such that the leading link is coupled to the clevis by the pin member. A preferred embodiment of the present invention provides a safety chain attachment device for use with a safety chain having a plurality of links, the links including a leading link and a following link connected to the leading link, the device including: a clevis having first and second sides and an aperture passing between the first and second sides; and a clevis pin receivable in the aperture to tether the leading link to the clevis; wherein the clevis includes, between said first and second sides, a seating region which is contoured to accommodate at least a surface geometry of the leading link, such that a clearance between the clevis and the leading link is minimised when the clevis pin is received in the aperture. A preferred embodiment of the invention provides a clevis for a safety chain attachment device for use with a safety chain having a plurality of links, the links including a leading link and a following link connected to the leading link, the clevis including: first and second sides and an aperture passing between the first and second sides; and a seating region between the first and second sides, wherein the seating region is contoured to accommodate at least a surface geometry of the leading link, such that a clearance between the clevis and the leading link is minimised when a clevis pin is received in the aperture.

Preferably, the seating region is also contoured to accommodate a surface geometry of the following link, to minimise a clearance between the clevis and the following link. A preferred embodiment of the present invention provides a safety chain attachment device for use with a safety chain having a plurality of links, the links including a leading link and a following link connected to the leading link, the device including: a clevis having first and second sides and an aperture passing between the first and second sides; and a clevis pin receivable in the aperture to tether the leading link to the clevis; wherein the clevis includes, between said first and second sides, a slot to receive the leading link, the slot having a width substantially equal to a width of the leading link such that a clearance between the clevis and the leading link is minimised when the clevis pin is received in the aperture.

Preferably, the slot has a surface which is contoured to accommodate a surface geometry of the leading link.

By minimising the clearance between the clevis and the leading chain link or the following link, it is possible to provide a greater amount of material between the first and second sides whilst minimising the footprint and overall size of the attachment device, thereby greatly increasing the strength and load-bearing capability of the clevis and greatly reducing any tendency for the two sides of the clevis to be forced apart.

The seating region may include a first surface which is complementary to the surface geometry of the leading link. In addition, or alternatively, the seating region may have a second surface or second surfaces which is or are complementary to the surface geometry of the following link.

The clevis may have a base with a perimeter region for welding to a support surface. Preferably, the perimeter region is recessed in a region adjacent to the seating region. This provides for a larger perimeter, and thus greater weld strength, without increasing the footprint of the clevis.

In preferred embodiments, the clevis pin includes opposed flattened regions at least partway along its length such that a clearance between the clevis pin and the leading link of the chain is minimised. The flattened regions allow for a greater thickness of clevis pin to be used for given internal dimensions of the link, thus providing extra support between the two sides of the clevis and further reducing any tendency for the two sides to be forced apart. Preferably, the flattened regions do not extend along the entire length of the pin.

The clevis pin may be securable to the clevis by way of a wire lanyard which is attached to one end of the pin, looped over or through the clevis and locked to the other end of the clevis pin using, for example, a lynch pin.

Preferably, the second surface rotates at least partially along a longitudinal axis of the clevis, to allow the following link to slide along the second surface. This allows the leading link and the following link to rotate to a limited extent along the longitudinal axis. Preferably, the second surface permits rotation of the leading link by up to about 90 degrees.

In certain embodiments, the clevis may extend from a base plate. The base plate may have holes to receive fasteners for fastening the clevis to a support surface. The clevis may be integrally formed with the base plate, or may be welded to it, for example. A preferred embodiment of the present invention includes a clevis pin for tethering a chain link to a clevis having first and second sides, the clevis pin being receivable in an aperture extending between the first and second sides, the clevis pin having a length and including: a first flattened section extending partially along the length of the pin, a second flattened section opposite the first flattened section, and a curved section spanning between the first and second flattened sections, such that the clevis pin in the region of the first and second flattened sections has a surface geometry which substantially conforms to an interior surface geometry of the chain link at one end of the chain link.

Preferred embodiments of the invention will now be described, by way of non-limiting example only, with reference to the accompanying drawings in which:

Figure 1 is an isometric view of a clevis according to an embodiment of the present invention;

Figure 2 is a right side projection view of the clevis of Figure 1;

Figure 3 is a top projection view of the clevis;

Figure 4 is a front projection view of the clevis;

Figure 5 is an isometric view of an embodiment of a safety chain attachment device including the clevis of Figures 1 to 4 and a clevis pin, in use with a chain;

Figure 6 is a cutaway view of Figure 5;

Figure 7 is a front projection view of the attachment device and chain;

Figure 8 is a top projection view of the attachment device and chain;

Figure 9 is an isometric view illustrating the range of movement of the chain;

Figure 10 is a left side projection view of Figure 9;

Figure 11 is a cross-section through the line A-A of Figure 10;

Figure 12 is an isometric view of an alternative embodiment of a clevis;

Figures 13 and 14 are front and top projection views of the clevis of Figure 12;

Figure 15 is an isometric view of an embodiment of a clevis pin;

Figures 16 and 17 are top and right side projection views of the clevis pin of Figure 15; and

Figure 18 is a cross-sectional view of the clevis pin positioned within a chain link.

Referring to Figures 1 to 4, there is shown a clevis 10 including a first side generally indicated by reference numeral 20 and a second side indicated by reference numeral 30. The clevis 10 has a downwardly curving upper surface 14 and a base 16 which is substantially flat for placement on a support surface. The base 16 has a bevelled edge 12 at each side 20, 30.

In the embodiment shown in the Figures, the clevis 10 is symmetric about a longitudinal axis, such that the first 20 and second 30 sides are identical, though it will be appreciated that in some embodiments it may be possible to introduce asymmetry between the two sides without reducing the rated capacity of the clevis under load.

To affix the clevis 10 to a support surface, such as a front surface or underneath surface of a trailer or tow bar, it is welded to the support surface (by any suitable method, such as MIG or arc welding) around a perimeter of its base. In addition, the clevis has recessed portions 40, 41 at opposite ends. Advantageously, this allows a greater perimeter at the base, thereby permitting a longer weld join, without increasing the footprint of the clevis and without substantially affecting the load transfer properties.

First side 20 includes a first boss 22 and second side 30 includes a second boss 32. Each boss 22, 32 has an aperture 24, 34 extending through it so as to receive a clevis pin in a manner which will later be described.

Each side 20, 30 has a recessed region 50. Recessing of the sides 20, 30 in this manner reduces the mass of the unit 10, and limits the maximum thickness through any given cross section, for welding purposes.

Between the first side 20 and the second side 30 there is a recessed seating region or slot, generally indicated by dotted outline 300 in Figure 3. The seating region includes a first surface portion 310 and second surface portions including surface portions 302, 312 on the first boss 22 and surface portions 304, 314 on the second boss 24, adjacent to the first surface 310. Surface portion 302 transitions smoothly into surface portion 312. Likewise, surface portion 304 transitions smoothly into surface portion 314. Surface portions 302, 312, 304 and 314 taper inwardly from the edges of their respective bosses 22, 32 towards the centre of clevis 10.

The width of slot 300 is substantially equal to the width of a link of a chain (for example, a chain compliant with AS2321-2006, “Short-link chain for lifting purposes”) which is to be tethered to the clevis 10. Advantageously, the use of a seating region (slot) with the minimum (or close to the minimum) width required to accommodate the chain link allows a greater volume of material to be provided in the central part of the clevis 10. Further, contouring the slot to accommodate the surface geometry of the links 500, 510 allows even greater volume of material to be provided. This improves the load bearing capacity in the transverse direction (i.e. the direction extending along apertures 24, 34), reducing any tendency for the sides 20, 30 of the clevis 10 to be forced apart under load.

As best shown in Figures 6, 8 and 11, the first surface 310 is contoured to match the surface geometry of a leading link 500 of a chain when it is received in the seating region 300 and tethered to the clevis by a clevis pin. The second surface portions are contoured to match the surface geometry of a following link 510.

Referring now to Figures 5 to 11, the clevis 10 is shown in use with a clevis pin 60 which is used to tether a chain, having a leading link 500 and a following link 510, to the clevis 10. It will be appreciated that, in general, there will be a plurality of links joined to the leading link; only links 500 and 510 are shown in the Figures for the purposes of illustrating the principles of the present embodiments.

To tether the leading link 500 to the clevis 10, it is nestled in the clevis on first surface 310, which complements the geometry of the outer surface of at least the end of the leading link 500, as illustrated in Figure 6. As will be observed from Figures 6 and 11, in this position the following link 510 is seated against second surface portions 302, 304. The clevis pin 60 is then passed through aperture 34 of the second boss 32, the leading link 500, and aperture 24 of the first boss 22. To secure the pin 60 in place, a wire lanyard (not shown) is secured at a tail 64 of the pin 60 via hole 74, passed through holes 44 and 42 at the front of the clevis 10 (Figure 5), and then attached to head 62 of pin 60 via hole 72, for example using a lynch pin or other suitable component.

In preferred embodiments, the head 62 of the clevis pin 60 may include a groove (not shown) to accommodate a circlip or other component, which bears against boss 22 to restrain the pin 60 against transverse movement relative to the clevis 10. This improves load transfer into the pin 60, thus further reducing any tendency for the clevis sides 20, 30 to be forced apart. As will be appreciated, any number of other means of securing the clevis pin may be employed to achieve the same or a similar effect, including but not limited to a pin, bolt, or tapered shank bolt.

As illustrated in Figures 9 and 10, the leading link 500 and following link 510 may rotate relative to the clevis 10 in a plane perpendicular to the axis of the pin 60. This is made possible by the contouring of surface portions 312, 314, which allow the outer surface of leading link 500 to slide over them. The links 500, 510 may be rotatable by up to an angle of 0max, until they are in the positions 500', 510' shown in phantom in Figures 9 and 10. Preferably, 0maxis no less than 90 degrees.

As can be seen clearly from Figures 6, 8, 9 and 11, a close fit between the clevis 10 and each of the leading link 500 and following link 510 is maintained as the links rotate, through the angle 0max, between the positions shown in Figure 10.

Referring now to Figures 12 to 14, there is shown an alternative embodiment 1200 of a clevis with an upper portion 1210 and a base 1280 suitable for bolt-on applications (via bolt holes 1282). The structure of the upper portion 1210 is substantially the same as that of the clevis 10 shown in Figures 1 to 11 and the reference numerals for like parts used in Figures 12 and 13 correspond to those used in Figures 1 to 9, but incremented by 1200. In Figure 14, reference numerals labelling the surface portions of the bearing surfaces are incremented by 1100 with respect to those used in Figures 1 to 9.

The base 1280 may be integral with the upper portion 1210, so that the clevis 1200 is formed as a unitary component. Alternatively, upper portion 1210 may be affixed to base 1280 by any suitable means, for example by welding.

Turning now to Figures 15 to 18, there is shown an embodiment of a clevis pin 60 suitable for use with the above arrangements. The clevis pin 60 has a head 62, a tail 64 and a body generally indicated by reference numeral 66. The head 62 has a hole 72 for receiving a lynch pin (for example) at one end of a wire lanyard, and the tail 64 has a hole 74 for receiving and securing the other end of the wire lanyard.

The body 66 of clevis pin 60 has flattened portions 1502, 1504 extending partially along its length and located either side of a curved upper portion 1510. When leading link 500 is tethered to the clevis 10 or 1200 using the clevis pin 60 (Figures 5 to 11), then as shown in Figure 18, the upper curved portion 1510 mates with an upper curved portion 502 on an internal surface of link 500, while flattened portions 1502, 1504 mate with respective flat internal surface portions 506, 504 of the link 500, such that the clevis pin 60 occupies the maximum possible width within the link 500 (to within a tolerance which allows the pin to be relatively readily inserted within the link 500). Accordingly, the clevis pin 60 may be made larger, and thus stronger, than would otherwise be the case if a pin with a constant, circular, cross-section was used.

It will be appreciated that various modifications, additions and alterations may be made to the invention by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

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

Claims

1. An attachment for use with a safety chain having a leading link and a following link connected to the leading link, the attachment being configured with a mount, via which it is secured or securable against a support surface, and comprising a clevis having first and second lateral side sections and an opening, between the sections, into which a leading end of the leading link is receivable, the sections being arranged to receive a pin member such that the pin member extends across the opening to couple the leading link to the clevis when the leading end is received in the opening, wherein a portion of the clevis defined between the sections has a configuration complementary to a configuration of the leading end of the leading link in a plane perpendicular to an axis of the pin member, whereby, when the leading link is coupled to the clevis by the pin member, there is maintained a close fit between the clevis and chain as the leading link and following link rotate relative to the clevis about the axis of the pin member.

2. An attachment for use with a safety chain having a leading link and a following link connected to the leading link, the attachment being configured with a mount, via which it is secured or securable against a support surface, and comprising a clevis having first and second lateral side sections and an opening, between the sections, into which a leading end of the leading link is receivable, the sections being arranged to receive a pin member such that the pin member extends across the opening to couple the leading link to the clevis when the leading end is received in the opening, wherein portions of the sections have configurations complementary to a configuration of a leading end of the following link, whereby, when the leading link is coupled to the clevis by the pin member, there is maintained a close fit between the clevis and chain as the leading link and following link rotate relative to the clevis about an axis of the pin member.

3. An attachment according to claim 2, wherein a portion of the clevis defined between the sections has a configuration complementary to a configuration of the leading end of the leading link in a plane perpendicular to said axis of the pin member, whereby, when the leading link is coupled to the clevis by the pin member, there is maintained a close fit between the clevis and chain as the leading link and following link rotate relative to the clevis about said axis of the pin member.

4. An attachment according to claim 2 or 3, wherein said portions of the sections are transversely curved so as to conform to a curvature of the leading end of the following link which curvature extends in a direction from one lateral side of that end to the other lateral side of that end.

5. An attachment according to claim 4, wherein said axis of the pin member is a central axis of the pin member and portions of the sections are curved about an axis of curvature which, when the pin member is received by the sections so as to extend across the opening, is coincident with said central axis of the pin, thereby permitting rotation of the leading link and following link about the central axis.

6. An attachment according to claim 5, wherein the first and second sections are configured with a concavity which is curved about the axis about which the sections are curved, the concavity being interrupted by said opening.

7. An attachment according to claim 6, wherein the concavity is curved through an angle of at least 90° about its axis of curvature, whereby said rotation can be through an angle of at least 90°.

8. An attachment according to any one of claims 5 to 7, wherein said portions of the sections are configured such that the leading end of the following link can slide over those portions during said rotation.

9. An attachment according to claim 1 or 3, or any one of claims 4 to 8 as dependent from claim 1 or 3, wherein said axis of the pin member is a central axis of the pin member and said portion defined between the sections is curved about an axis of curvature which, when the pin member is received by the sections so as to extend across the opening, is coincident with said central axis of the pin member, whereby to conform to a curvature of the leading end of the leading link.

10. An attachment according to claim 9, wherein said portion defined between the first and second sections is so curved through an angle not exceeding 90° so as to permit rotation of the leading link about the axis of curvature.

11. An attachment according to claim 1 or 3, any one of claims 4 to 8 as dependent from claim 1 or 3, or either one of claims 9 and 10, wherein said portion of the clevis is transversely curved so as to conform to a curvature of the leading end of the leading link which curvature extends from one lateral side of that leading end to the other lateral side of that leading end.

12. An attachment according to any one of the preceding claims, comprising a base defining said mount, wherein a perimeter region of the base is weldable or welded to the support surface.

13. An attachment according to any one of claims 1 to 11, comprising a base defining said mount, the base being configured with holes through which can be received respective fasteners to secure the base against the support surface.

14. An attachment according to any one of the preceding claims, being secured against the support surface via said mount.

15. An attachment according to any one of the preceding claims, including said pin member.

16. An assembly comprising: an attachment according to claim 15; and said chain, wherein the pin member is received by the first and second side sections, so as to extend across the opening, and the leading end of the leading link is received in the opening such that the leading link is coupled to the clevis by the pin member.

17. An assembly according to claim 16, wherein the pin member is rotatable, about a central axis thereof, with respect to the clevis.

18. An assembly according to claim 16 or 17, wherein the pin member comprises a cylindrical shank configured with diametrically opposed flats passing through the opening through the leading link, the flats being separated by a distance not greater than a width of the opening.

19. An assembly according to claim 18, wherein said distance is substantially equal to said width.

20. An assembly according to claim 18 or 19, wherein the flats extend only partway along the shank.

21. An assembly according to any one of claims 16 to 20, wherein the pin member is tethered to the clevis.

22. An attachment according to any one of claims 1 to 15, substantially as hereinbefore described with reference to the accompanying drawings.

23. An assembly according to any one of claims 16 to 21, substantially as hereinbefore described with reference to the accompanying drawings.