A GATE ASSEMBLY INCORPORATING A TORSION SPRING CLUTCH FIELD OF THE INVENTION

This invention relates to a torsion spring clutch for a gate assembly or the like. PRIORITY

This patent application claims priority from:

Australian Provisional Patent Application 2010901561 , titled "A GATE AS SEMBL Y

INCORPORATING A TORSION SPRING CLUTCH", and filed on 13 April 2010;

The entire content of this application is hereby incorporated by reference. BACKGROUND OF THE INVENTION

Throughout the specification and the claims that follow, unless the context requires otherwise, the word gate will be understood to be inclusive of any movable barrier in a fence or wall or the like.

For the purpose of explanation, reference will be made to an ingress gate for a horse racing starting barrier, although it will be understood by a person skilled in the relevant art that the invention need not e so limited in its application.

The ingress gate for a horse racing starting barrier is the gate via which the horse enters the starting barrier. Once closed behind the animal, this ingress gate must be held closed so as to prevent the rearward egress of the animal while awaiting the start of the race.

An object of the present disclosure is to provide a gate assembly which may, at the least, serve as a useful alternative to known ingress gates for horse racing starting barriers.

Other objects and advantages of the present invention will become apparent from the following description, taken in connection with the accompanying drawings, wherein, by way of illustration and example, an embodiment of the present invention is disclosed. SUMMARY OF THE INVENTION

In one aspect, the invention may be said to reside in a gate assembly comprising a gate which is pivotally supported so as to have a pivotal axis of rotation, a helical torsion spring element coiled in or about a shaft having a direction of elongation which is substantially coaxial with the pivotal axis of rotation of the gate, the helical torsion spring element having a first end which is fixed relative to the gate, and a second, distal end, and wherein in use, the helical torsion spring element will either rotate or frictionally engage and thereby lock relative to the shaft depending upon whether a force applied to either of the gate and/or the distal end of the helical torsion spring element causes this to further wind or unwind.

In a further aspect, the invention may be said to reside in a clutch assembly for a gate which is pivotally supported so as to have a pivotal axis of rotation, the clutch assembly comprising a helical torsion spring element coiled in or about a shaft having a direction of elongation which is substantially coaxial with the pivotal axis of rotation of the gate, the helical torsion spring element having a first end which is fixed relative to the gate, and a second, distal end, and wherein in use, the helical torsion spring element will either rotate or frictionally engage and thereby lock relative to the shaft depending upon whether a force applied to either of the gate and/or the distal end of the helical torsion spring element causes this to further wind or unwind. In one form, the helical torsion spring element is coiled around the shaft, and in use, the helical torsion spring element will either rotate about or lock relative to the shaft depending upon whether a force applied to either of the gate or the distal end of the helical torsion spring element causes this to further wind onto and thereby tighten its grip upon the shaft, or unwind so as to permit rotation of the gate.

In one form, the helical torsion spring element is coiled inside of the shaft, at least a portion of the shaft being tubular, and in use, the helical torsion spring element will rotate inside of or lock relative to an inner wall of the shaft depending upon whether a force applied to either of the gate or the distal end of the helical torsion spring element causes the spring to unwind and thereby lock relative to the inner wall of the tubular shaft, or wind as to permit rotation of the gate.

In one form, the distal end of the helical torsion spring element is acted upon by a user operable means which translates its operation into the rotational force required to wind or unwind the helical torsion spring element as required.

In one form, the user operable means provides a mechanical advantage to the user. In one form, the user operable means is a lever.

In one form, both the gate end of the helical torsion spring element and the lever extend in the same approximate direction as each other, but from opposite sides of the shaft.

In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of embodiments in addition to those described and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate certain embodiments of the invention, and together with the description, serve to explain the principles of the invention.

Those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilised as a basis for designing other structures, methods, and systems for carrying out the several purposes of the present invention. It is important, therefore, to recognise that any claims should be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS For a better understanding of this disclosure it will now be described with respect to one or more exemplary embodiments, which shall be described herein with the assistance of drawings wherein:

Figure 1 is a perspective view of a gate assembly;

Figure 2 is detailed perspective of a clutch assembly from the gate in Figure 1 ;

Figure 3 is a perspective view of a pair of mirrored gate assemblies being used as ingress gates for a horse racing starting barrier; ' . ^■

Figure 4 is a detailed perspective view of the gate assemblies of Figure 3;

Figure 5 is a cross-sectional view through a portion of the gate assemblies of Figures 3 and 4, the section being taken across X-X;

Figure 6 is a perspective view of a gate assembly from Figure 3;

Figures 7a, 7b and 9 are detailed perspective views of a clutch assembly from a gate assembly illustrated in Figure 3; Figures 8a and 8b are exploded views of the clutch assembly illustrated in Figures 7a and 7b, Figure 8a having an upper viewpoint of the assembly, and Figure 8b having a lower viewpoint of the assembly ;

Figure 10 is a perspective view of a gate assembly according to a further exemplary embodiment; Figure 1 1 is a cross-sectional view through a torsion spring clutch assembly of the gate assembly illustrated in Figure 10, this being taken across plane x-x; and

Figure 12 is a detailed cross-sectional view through the torsion spring clutch assembly utilised in the gate assembly illustrated in Figures 10 and 11 , this being taken across plane x-x.

In the following description, like reference characters designate like or corresponding parts throughout the several views of the drawings.

DETAILED DESCRIPTION OF THE DISCLOSURE

Referring now to Figure 1 , where an exemplary embodiment of a gate assembly 1 is illustrated.

The gate assembly 1 includes a gate 2 comprising a fabricated steel framework depending from three spaced apart but aligned collar portions 4, which in turn are disposed upon a shaft 6 so that the gate 2 may rotate about the shaft.

A helical torsion spring element 10 is coiled around the shaft 6, and it is sized and adapted so as to frictionally engage the shaft 6 when it is externally unloaded. The helical torsion spring element 10 illustrated is coiled from wire of round section, but different wire forms may be employed depending on the specific application. For instance, square wire offers the advantage of increased load capability as compared with round wire of the same size.

The helical torsion spring element 10 has first and second ends, a first of which 10a is fixed relative to the gate by virtue of being captured between tabs 12 and 14. It will be understood by the skilled addressee however that various methods may be employed to fix the helical torsion spring end to the gate, including but not limited to, a swaged end, a thread formed in the end, or securing the end with a nut etc. ■ ^■ · „ ^{■ '}

The second end 10b of the helical torsion spring element 10 extends outward from the shaft 6 in the same general direction as the gate 2 (but from the other side of the shaft 6 to the first end 10a of the helical torsion spring element 10) forming a lever 15, which is slightly misaligned with respect to the gate 2. In use, any attempt to force the gate 2 in direction A in this case, will cause the spring 10 to be further wound around shaft 6, thereby tightening around this.

Should a user wish to rotate the gate 2 in this direction though, they need only push the lever 15 in direction AA (which is substantially parallel to direction A) whilst (optionally) pushing the gate 2 in direction A, as this will cause sufficient unwinding of the spring 10 relative to the shaft 6 that the spring 10 (and gate 2) may slip relative to the shaft 6 permitting rotation of the gate 2.

In contrast, any attempt to force the gate in direction B, will, in and of itself, cause sufficient unwinding of the spring 10 relative to the shaft 6 that the spring (and gate) may slip relative to the shaft. The principle of operation of the gate and torsion spring clutch in particular may be as follows. The helical torsion spring element is adapted to rotate about the shaft or lock relative to the shaft depending upon whether a force applied to an end of the helical torsion spring element causes a radial force exerted by the helical torsion spring element upon the shaft to increase and thereby tighten its grip upon the shaft (thereby increasing friction), or decrease so as to permit rotation. When utilised as an ingress gate for a horse racing starting barrier, a gate assembly 1 may be supported from an upright shaft, which itself may form part of the starting barrier. The gate 2 is closed behind the animal by being pushed (or driven) in direction B. Any attempt by the animal to force the gate in direction A (ie to egress this way) will be resisted by the operation of the torsion spring element clutch assembly. This demonstrates the importance of lever 15 being slightly misaligned with respect to the gate 2 (or otherwise guarded), as this prevents any operation of this by the animal as they push against the gate 2.

Advantages of the torsion spring clutch assembly and gate assembly disclosed herein include:

> Their operation is virtually silent; this is particularly useful given their potential for use near horses;

> The gate can be opened up to a much wider angle than that permitted by known ingress gates for a horse racing starting barrier;

> The gate may be opened in a controlled fashion by the user, even though the animal is bearing against it;

> Both the torsion spring clutch and gate assembly are simple and therefore reliable and

inexpensive to build; > Both the torsion spring clutch and gate assembly can be locked in position at any angle of rotation; and .

> Releasing the gate for rotation requires no forward motion of the gate as is the case with an over-centre latch. With reference now to Figures 3 through 5, where a pair of gate assemblies 1 A are mounted so as to be suspended from structure 20 delineating a pair of adjacent stalls 22 of a horse racing starting barrier. These two gate assemblies 1 A effectively mirror one another about the upright elements of support structure 20.

Identical pairs of gate assemblies 1 A may be mounted to common support structure either side of a stall 22 (although such further identical pairs are not illustrated), so that one gate 2 from each of the assemblies 1 operate together to close an animal in its stall 22.

Whilst the gate assemblies 1 A illustrated in Figures 3 through 5 operate in the same way as the gate assembly 1 illustrated in Figures 1 and 2, some design details differ.

With reference to Figures 8a and 8b, it can be seen that helical torsion spring element 10 is coiled around a spindle 30 that is secured relative to the support structure 20 by teeth 30a, and the spring 10 and spindle 30 are housed within a cylindrical guard 40, which serves to eliminate the pinching hazard posed by the spring 10. The spindle 30 has a function that is analogous to that of the shaft 6 referenced above.

A cap 32 sits atop the cylindrical guard 40, and the lever 15 is attached to the cap 32. The cap 32 is in turn bolted to a drive plate 33 having an underside from which there extends a downwardly extending key 33a (see Figure 8b) which locates in a slot 35 in an upper spring bearing 34 so that this upper spring bearing 34 is forced to rotate with the cap 32. The upper spring bearing 34 has an end 34a which is brought to bear against the free end 10a of the helical torsion spring element 10 as cap 32 is rotated in a direction opposing the winding direction of the spring 10. Referring now to Figure 9, where it can be seen the end 10b of the spring 10 is captured between flanges 48 and bolted to the gate 2 A via a bolt 46 through the flanges 48.

With reference to Figure 3, any attempt to force the gate 2A in direction A (ie from the inside of the stall 22) in this case, will cause the spring 10 to be further wound around spindle 30, thereby .

tightening around this. This is by virtue of spring end 10a being fixed relative to the gate 2 by the bolt 46. Should a user wish to rotate the gate 2A in this direction (ie. so as to open the gate 2A) though, they need only push the lever 15 in direction AA (which is substantially parallel to direction A) as this will cause sufficient unwinding of the spring 10 relative to the spindle 30 that the spring 10 (and gate 2A) may slip relative to the spindle 30 permitting rotation of the gate 2A. The risk of any unintended opening of the gate 2A, such as may be caused by accidental bumping of the lever 15, is reduced by there being some relative movement permissible between the cap 32 and drive plate 33. The cap 32 is secured to the drive plate 33 by bolts 37 extending through slots 39 in the cap 32. Drive is not transmitted from the cap 32 to the drive plate 33 until a driving end of the slots 39 meets the bolts 37. Moreover, the cap 32 is biased away from its driving position by a spring 41. Any attempt to force the gate in direction B (ie from the outside of the stall), will, in and of itself, cause sufficient unwinding of the spring 10 relative to the spindle 30 that the spring (and gate) may slip relative to the spindle 30.

When the or each gate 2 is closed behind the animal by being pushed (or driven) in direction B, any attempt by the animal to force the gate in direction A (ie to egress this way) will be resisted by the operation of the torsion spring element clutch assembly.

With reference now to Figures 10 through 12, where there is illustrated a gate assembly 400 incorporating a helical torsion spring element 402 coiled inside of a tubular shaft 404. This tubular shaft 404 is adapted to be fixed relative to support structure for the gate via base plate 403. One end 402a of the helical torsion spring element 402 passes through a cut-out in the tubular shaft 404 and is connected to a gate 406. The other end 402b of the helical torsion spring element 402 passes through a second cut-out in tubular shaft 404 and is connected to a lever 408 having an axis of rotation which is aligned with that of the gate 406 and helical torsion spring element 402.

The helical torsion spring element 402 is adapted to selectively rotate inside of or lock relative to the tubular shaft 404 depending upon whether a force applied to an end 402a or 402b of the helical torsion spring element 402 causes the helical torsion spring element 402 to unwind and thereby expand in overall diameter and frictionally engage the inner surface of tubular shaft 404, or wind and thereby reduce in overall diameter and permit rotation of the spring 402 relative to the inner surface of tubular shaft 404.

In use, any attempt to force the gate 406 in direction A in this case, will cause the spring 402 to be unwound, expanding this so that it engages the inner surface of the tubular shaft 404.

Should a user wish to rotate the gate 406 in A direction though, they need only push the lever 408 in direction AA (which is substantially parallel to direction A) whilst (optionally) pushing the gate 406 in direction A, as this will cause sufficient winding (ie reduction in diameter) of the spring 402 relative to the tubular shaft 404 that the spring 402 may slip relative to inner surface of the tubular shaft 404, permitting rotation of the gate 406.

In contrast, any attempt to force the gate in direction B, will, in and of itself, cause sufficient winding of the spring 402 relative to the tubular shaft 404 that the spring 402 may slip relative to inner surface of the tubular shaft 404, thereby permitting rotation of the gate 406.

When utilised as an ingress gate for a horse racing starting barrier, this gate assembly 400 may be supported from starting barrier structure. The gate 406 is closed behind the animal by being pushed (or driven) in direction B. Any attempt by the animal to force the gate in direction A (ie to egress this way) will be resisted by the operation of the torsion spring element clutch assembly.

With the embodiment of the invention described above with reference to figures 1 to 9, the "shaft" is a simple vertically orientated pole that is generally cylindrical in shape. In other embodiments of the invention not shown, the shaft may be a more complex shape,- for instance the shaft may have a generally circular cross section but may have '.'flat" or other external features. The "shaft" must have a surface to provide frictional engagement with a co-operating torsional spring, but may take various forms, provided this characteristic is met.

It can be seen then that what has been conceived is a simple but useful, effective and elegant torsion spring clutch assembly and a gate assembly incorporating the same.

Throughout the specification and the claims that follow, unless the context requires otherwise, the words "comprise" and "include" and variations such as "comprising" and "including" will be understood to imply the inclusion of a stated integer or group of integers, but not the exclusion of any other integer or group of integers.

The reference to any prior art in this specification is not, and should not be taken as, an acknowledgement of any form of suggestion that such prior art forms part of the common general knowledge.

It will be appreciated by those skilled in the art that the invention is not restricted in its use to the particular application described. Neither is the present invention restricted in its preferred embodiment with regard to the particular elements and/or features described or depicted herein. It will be appreciated that various modifications can be made without departing from the principles of the invention. Therefore, the invention should be understood to include all such modifications in its scope.