AU2006235856B1 - Spring loaded removable spacer - Google Patents

Description

Spring Loaded Removable Spacer Field of the Invention.

This invention is directed to a system whereby roof trusses can be erected into place in a safe manner, and the invention is also directed to devices which can enable the truss erection to be carried out.

Background Art.

It is very common to use roof trusses in a building and to which the roofing sheets can be attached usually via battens.

The roof trusses are typically manufactured off-site in a factory and transported to a building site. A crane or something similar then lifts the roof trusses into position.

The building contains vertical support walls, and the trusses are placed on top of the support walls. The support walls are typically either made of timber or blocks. If the support walls are made of timber, the walls typically comprise a vertical framework of timber studs. If the support walls are made of blocks, the uppermost course of blocks is known as the bond beam.

The trusses are delivered to site and it is necessary to lift and erect each truss to the vertical position. It is very important that the trusses are placed in exactly in the correct position. Thus, the trusses need to be spaced apart by a precise distance and also need to be positioned on top of the support walls in exactly the right place.

Thus, it is normal for a worker to be positioned on top of the walls to position each truss into the correct position. However, this creates the risk situation as there is very little protection against falling. Also, it is common for the trusses to be positioned using the crane and lifting chains, and sometimes the truss can strike the worker causing injury.

It is known to position anchors (often known as cleats) on the top of the support walls and against which the trusses will be nailed or otherwise attached. These cleats typically comprise metal plates or something similar which are either anchored in the concrete of the top wall (if blocks are used) or nailed or otherwise fastened to the beam on the top wall.

It is normal for a worker to stand on the truss high above the ground whilst a crane lifts another truss into place. The truss is then temporarily nailed to the previous fixed truss with a timber batten.

To improve safety, there would be an advantage if it were possible to place trusses into position without requiring a worker to stand on the truss high above the ground.

There would also be an advantage to provide devices which could assist in the erection of trusses in a safer manner, for instance by allowing the worker to manipulate the truss from the ground, or by allowing the trusses to be placed into the correct position (for instance against the pre-formed cleats) in a safer manner. Thus, one aspect of the present invention may comprise a system and various devices that may enable trusses to be positioned accurately in place without with a reduced requirement for workers to be positioned high above the ground.

Another aspect of the invention may comprise one or more devices that may make erection and positioning of trusses simpler.

It will be clearly understood that, if a prior art publication is referred to herein, this reference does not constitute an admission that the publication forms part of the common general knowledge in the art in Australia or in any other country.

Object of the Invention.

3 0 It is an object of the invention to provide a truss erecting system and/or various devices to assist in the erection and positioning of trusses and which may overcome existing disadvantages or provide a useful or commercial choice.

7- 3 In one form the invention resides in a spacer apparatus to enable a pair of trusses to be held relative to each other, the apparatus comprising an elongate member adapted to extend at least between a pair of adjacent trusses in use, a connector on the elongate member to enable the apparatus to be attached to a first truss prior to the first truss being lifted into position, and a grabbing jaw on the elongate member and spaced from the connector, the grabbing jaw having a first jaw member and a second jaw member and being operable between a clamping position to clamp against a second truss, and a release position, biasing means to bias the grabbing jaw to the clamping position, and a trigger to cause the grabbing jaw to move from the release position to the clamping position.

The spacer apparatus may conveniently be called a truss spacer.

Suitably, the grabbing jaw is able to move from the release position to the clamping position upon placement of a portion of the second truss against one of the jaw members and placing a force against the one jaw member. Alternatively, some other form of triggering action may be provided.

In this manner, the truss spacer can be attached to a particular truss (conveniently called the first truss) while the truss is still on the ground and by clamping the connector to the truss. The truss can then be lifted into position and this will result in the elongate member being "cantilevered" substantially horizontally from one side of the first truss, with the grabbing jaw typically being on the end of the elongate member and in the release position. A second truss can then be lifted and manipulated such that it presses against one of the jaw members and this causes the jaw members to snap shut to the clamping position to clamp the second truss in position. Prior to lifting of the second truss, another truss spacer is attached to the second truss such that when the second truss is clamped in position, it will have its own cantilevered truss spacer and a third truss can then be lifted in position and clamped etc etc.

It is considered that the use of this type of truss spacer is much superior than requiring a worker to temporarily nail adjacent trusses into position using scrap wood. Once all the trusses are in position and properly fixed, the various truss spacers can be removed and reused. It is considered that this arrangement will be much safer than the traditional way of positioning trusses.

It is envisaged that a single truss spacer will be used to hold a pair of trusses relative to each other. However, there may be circumstances where two or more truss spacers may be used.

The truss spacer can be attached to any suitable part of the truss.

The term" first truss" need not be the very first truss which is positioned on top of the walls, and the term is used to distinguish between one truss and another truss. It is envisaged that the very first truss will be positioned via a known system and is already in a stable position. This truss may not have the spacer. For instance, the next truss may contain two truss spacers, one to lock onto the very first truss, and the other extending in the opposite direction to lock to the next lifted truss. Other alternatives are also envisaged.

The spacer comprises an elongate member which is adapted to extend at least between a pair of adjacent trusses in use. Therefore, the elongate member will typically have a length of between 0.5-3 m, although this length can vary depending on the spacing between adjacent trusses.

The elongate member may be adjustable in length to make the truss spacer more versatile in use. Thus, the elongate member may be telescopically adjustable in length and therefore may comprise a pair of members which can slide (e.g.

telescopically) relative to each other to adjust the length of the elongate member.

However, it is also envisaged that the elongate member may contain a number of segments that may be attached together to adjust the length of the elongate member.

It is also envisaged that the elongate member is not adjustable in length but the connector and/or the grabbing jaw may be adjustably mounted relative to the elongate member thereby enabling the spacing between the connector and the grabbing jaw to be varied.

It is also envisaged that both elongate member may be adjustable in length and the connector and/or grabbing jaw may be adjustably mounted to provide versatility to the truss spacer.

In a particularly preferred embodiment, the elongate member is not length adjustable, the grabbing jaw is at one end of the elongate member and the connector is adjustably mounted to the other end of the elongate member.

The elongate member may be made of any suitable material and it is considered that steel or other metal and possibly some form of plastics may be suitable materials.

Fibreglass may also be suitable material. Certain laminates structures may also be suitable materials.

The elongate member may be solid or hollow or a combination of solid portions and hollow portions. Therefore, the elongate member may be tubular (which includes a rectangular cross-section as well as a circular cross-section) or have a solid rod like configuration. The elongate member may have any suitable cross-section shape and while it is preferred and envisaged that the elongate member will be rectangular or circular, it is considered that the elongate member may also be oval or have other polygonal or irregular shapes.

It is also envisaged that the elongate member may comprise a strip like material or a plate like material as opposed to a tubular material. Thus, the elongate member may be formed from a strip material, or "angled" material such as an L-shaped angle and the like.

It is also envisaged that the elongate member may be made from "channel" like material such as a U-shaped channel or a C-shaped channel and the like.

The truss spacer contains a connector on the elongate member. The connector is preferably connected directly to the elongate member but may also be connected indirectly to the elongate member possibly via some form of intermediate member. In most cases, it is considered suitable for the connector to be directly connected to the elongate member.

A function of the connector is to be attached to a truss. Therefore, the connector should have a configuration which enables it to do so. It is envisaged that there will be many ways by which a connector can be attached to a truss.

Thus, in one form, the connector may comprise a channel shaped body or have a first side wall and a second side wall which are spaced apart by a distance sufficient to enable a truss to be positioned in the channel or between the first side wall and the second side wall. The channel or the spacing between the sidewalls may be adjustable and therefore one side wall or both sidewalls may be adjustable relative to each other.

It is also envisaged that the connector can clamp to the truss such that it cannot be easily and inadvertently knocked off.

In one particularly preferred form, the connector comprises a first part which is adapted to be clamped to the elongate member and particularly in a releasable and adjustable manner such that the connector can be adjustably positioned on the elongate member, and a second part which is adapted to attach to a truss.

The first part may have a configuration which enables it to slide over or otherwise engage with the elongate member to enable the position of the connector to be adjusted. If the elongate member has a rectangular cross-section, the first part may also have a rectangular cross-section of slightly larger size to enable it to slide over the elongate member. Of course, it is envisaged that there will be other means by 7 which the connector can be adjustably mounted to the elongate member.

Some form of an adjustable locking means is envisaged to lock the connector to the elongate member at a desirable place. In a simple form, the adjustable locking means may comprise fasteners that can be loosened or tightened to lock the connector against the elongate member. The fasteners may comprise threaded fasteners, or some form of "cam" type fastener, or some form of "clamping" type fastener and the like. It is also envisaged that some form of "pin in slot" arrangement can be provided where the elongate member is provided with an array of slots and the connector contains, or is associated with some form of locking pin(s).

The truss spacer further contains a grabbing jaw which may be attached directly or indirectly to the elongate member. It is preferred that the grabbing jaw is "fixed" to the elongate member and that any adjustment in the spacing between the grabbing jaw and the connector is carried out by adjusting the position of the connector on the elongate member.

A function of the grabbing jaw is to lock against a truss when the truss is pushed against a part of the grabbing jaw. Therefore, a function of the grabbing jaw is to provide some form of automatic clamping of the truss. This will be explained in greater detail in the preferred embodiment. An advantage of this automatic clamping arrangement is that a person does not need to stand on top of the trusses but instead can stand on the ground and push or lift the truss against the grabbing jaw to cause the grabbing jaw to automatically clamp against the truss. It is also envisaged that the crane operator can manoeuvre the truss against the grabbing jaw.

It is envisaged that the truss spacer will have a mechanical type trigger to trigger the grabbing jaw to clamp against the truss. However, a more sophisticated system may comprise some form of electronic clamping, but this may require a solenoid or other type of component to trigger the grabbing jaw into the clamping position.

The grabbing jaw will typically comprise a first jaw member and a second jaw member between which a truss (which can conveniently be called the "second" truss) can be clamped. It is envisaged that one jaw member is movable and the other one is relatively fixed or that both jaw members can move to trigger the clamping action.

It is envisaged that there will be different types of grabbing jaw arrangements which may form part of the invention and which can trigger to clamp a truss between the jaw members.

In a preferred embodiment, the grabbing jaw may comprise a first jaw member against which the truss can be positioned, and a second jaw member which can move between a release position and a clamping position. The first jaw member may form part of an arrangement or assembly to trigger a second jaw member. For instance, the second jaw member may comprise some form of over centre mechanism connected by a rod or something similar to a triggering mechanism which, when triggered, will cause the second jaw member to move to the clamping position.

The triggering mechanism may comprise a ratchet mechanism with the first jaw member activating the ratchet mechanism when the truss is pressed against the first jaw member.

In another preferred embodiment (see for instance figures 13-14), there is provided a grabbing jaw which is somewhat similar to that described above except that the first jaw member contains a "trigger" which is activated when a truss is pushed against the first jaw member and which activates the second jaw member to move to the clamping position.

The shape and configuration of the first jaw member and a second jaw member may vary. It is however preferred that each jaw member comprises some form of elongate member or projection such that a truss can be clamped between the jaw members.

In another form, the invention resides in a truss controlling device which can enable a worker to position the truss in place while remaining on the ground. The truss 9 controlling device typically comprises a head portion. The head portion may be attached to a long pole or something similar either removably or permanently thereby allowing a worker to control the truss from the ground. The head portion comprises means to engage with the truss to enable the truss to be moved. The means is typically such that the truss controlling device can be attached and released from the truss in a relatively simple manner. A useful function of the truss controlling device is to manipulate the truss such that it engages against the grabbing jaw.

In a broad form of the invention there may be provided a spacer apparatus to enable a pair of trusses to be held relative to each other, the spacer comprising an elongate member adapted to extend at least between a pair of adjacent trusses in use, a connector on the elongate member to enable the apparatus to be attached to a first truss prior to the first truss being lifted into position, and a grabbing jaw on the elongate member and spaced from the connector, the grabbing jaw having a first jaw member and a second jaw member and being operable between a clamping position to clamp against a second truss, and a release position.

Brief Description of the Drawings.

Embodiments of the invention will be described with reference to the following drawings in which: Figure 1. Illustrates a truss spacer with the grabbing jaw in the "open" position.

Figure 2. Illustrates a close up view of the grabbing jaw in the "open" position.

Figure 3. Illustrates the grabbing jaw in the "closed" position where truss can be clamped in the grabbing jaw.

Figure 4. Is an inverted view of parts of the grabbing jaw particularly illustrating the ratchet mechanism.

Figure 5. Illustrates the truss spacer attached to one truss.

Figure 6. Illustrates in greater detail the connector which is on the other side of the truss spacer.

Figure 7. Illustrates the truss spacer in use and also illustrates the truss controlling device attached to a truss.

Figure 8. Illustrates the truss spacer in use and from a different angle.

Figure 9. Illustrates the head portion of the truss controlling device.

Figure 10. Illustrates the head portion of the truss controlling device attached to a truss.

Figure 11. Illustrates the other side of the truss with the head portion of the truss controlling device attached to the truss.

Figure 12. Illustrates the truss controlling device in use.

Figure 13. Illustrates a second embodiment of the invention and particularly a different design of the grabbing jaw and in the closed position.

Figure 14. Illustrates the grabbing jaw of figure 13 in the open position.

Figures 15 21 Illustrate a Third Embodiment of the Invention and in Particular: Figure 15. Illustrates a Truss Spacer in the Closed "Grabbing" Position.

Figure 16. Illustrates the truss spacer of figure 15 in the open "cocked" position.

Figure 17. Illustrates a close up view of the truss spacer of figure 16.

Figure 18. Illustrates a "underneath" view of the truss spacer and particularly illustrating the springs.

Figure 19. Illustrates an upper view of the truss spacer in the open "cocked" position.

Figure 20. Illustrates the truss spacer of the third embodiment in position and from one side.

Figure 21. Illustrates the truss spacer of figure 20 from the other side.

Figure 22. Illustrates the truss spacer of figure 15 from the other side.

Figure 23. Illustrates the use of modified truss spacers in a hip roof.

Best Mode.

Referring to the illustrations and initially to figure 1, there is illustrated a truss spacer 10 which comprises an elongate member 11 one end of which contains a connector 12 and the other end of which contains a grabbing jaw 13.

The truss spacer functions to temporarily lock an adjacent pair of trusses in place to assist in the safe erection of trusses. It is envisaged that each truss will contain a truss spacer and that the truss spacer can be reused many times.

The elongate member 11 comprises steel box section and typically has a length of between 1-2 m as this is the typical distance between adjacent trusses.

Connector 12 is slidingly attached to one end of the elongate member 11. Connector 12 is better illustrated in figure 6 and comprises a first part 14 which is rectangular in cross-section and which is sized such that it can slide over and along elongate member 11. Connector 12 further comprises a second part 15 which is welded to first part and which contains a substantially L-shaped portion containing one side wall 17, a "top" wall 18, a strengthening "gusset" wall 19, and a second side wall 20. The spacing between the sidewalls is such that a portion of a truss can extend between the sidewalls (an example of which is illustrated in figure If desired, a tension bolt assembly can be provided to prevent inadvertent removal of connector 12 from the truss. The tension bolt assembly may comprise a threaded rod 21 which is pivotally mounted to one side wall by pivot 22, and where a threaded rod extends through a suitable opening in side wall 17 and a nut 23 which can be rotated to lightly clamp the sidewalls against each side wall of the truss. After use, nut 23 can be loosened to remove (or more correctly pivot away) the threaded rod 21, thereby enabling connector 12 to be removed from the truss.

Connector 10 (best illustrated in figure can be clamped at any desirable position on elongate member 11 by a pair of threaded rods 24 which can be rotated to clamp (or counter rotated to loosen) connector 10 to elongate member 11.

Grabbing jaw 13 functions to automatically lock against a second truss merely by pushing parts of the second truss against part of the grabbing jaw. Figures 1-4 illustrate one embodiment of the grabbing jaw while figures 13-14 illustrate another embodiment of the grabbing jaw.

12 Referring initially to the embodiment of figures 1-4, the grabbing jaw comprises a first jaw member 26, and a second jaw member 27. Second jaw member 27 can move between a "free" position particularly illustrated in figure 1, and a "locking" position particularly illustrated in figure 3 where a truss portion 28 (see figure 5) can be clamped between the jaw members 26, 27. Second jaw member 27 contains an over centre mechanism which means that the second jaw member is pivotally mounted relative to elongate member 11 at a pair of spaced apart positions (29, 30 best illustrated in figure and is connected to a short rod 31. Movement of rod 31 will cause the second jaw member to move from the free position illustrated in figure 1 to the clamping or locking position illustrated in figure 3. It is envisaged that the second jaw member can be returned back to the free position by manually pulling the second jaw member from the position of figure 3 to the position of figure 1. However, the reverse can be done automatically by "triggering" the second jaw member 27 to move to the locking position illustrated in figure 3.

The triggering action is achieved by a mechanism whereby the first jaw member 26 is connected to the triggering action and therefore the first jaw member actually triggers locking of the second jaw member. This is achieved by pushing the first jaw member in the direction of arrow 32. The pushing is carried out by a second truss member being placed against the first jaw member 26 and then pushed against the first jaw member which causes the first jaw member to move in the direction of arrow 32.

The first jaw member 26 is attached to an elongate member which is at right angles to the first jaw member and which functions as a "rack" 33.

Slidingly attached to elongate member 11 (and best illustrated in figure 4) is a ratchet mechanism 34 which can be slidingly mounted to elongate member 11. The ratchet contains a spring-loaded pawl 36 which engages against rack 33 and which functions in the well-known manner of allowing rack 33 to move in one direction (the direction of arrow 32) but not in the other direction.

Ratchet mechanism 34 is mounted to a body member 37 which is box section in shape. One end of the box section is attached to elongate member 11 by locking screws 53 (see figure A measure of adjustability can also be made. The body member 37 contains a boss 38 (see figure 3) to which rod 31 is attached.

Referring to figure 2, first jaw member 26 is welded or otherwise attached to rack 33 and is also welded or otherwise attached to an elongate mounting section 54 which is a box section and which slides within body member 37. Put differently, body member 37 can slide over elongate mounting section 54. The second jaw member 27 is pivotally attached to the end of elongate mounting section 54 this being illustrated in figure 2 and figure 3.

The ratchet mechanism 34 can be adjustably mounted and releasably locked to body member 37.

When a force is placed against the first jaw member 26, it will push first jaw member in the direction of arrow 32. This movement will force the rack 33 and the elongate mounting section 54 to also move in the direction of arrow 32 and therefore the elongate mounting section 54 moves into the body member 37. Rod 31 (by being attached to the body member 37) will push against the end of the second jaw member 27 and at some stage the second jaw member will move to its "triggering" position where it will snap down to the clamping position illustrated in figure 3.

The distance of movement will probably be between 10-100 mm.

The movement of the first jaw member 26 in the direction of arrow 32 is limited by the end of rack 33 abutting against an abutment 52 (see figure Abutment 52 is adjacent the locking screws 53 which are illustrated in figure 1 as well as figure 4.

The ratchet mechanism prevents the first jaw member 26 from moving in the other direction (unless released by the spring mounted pawl 36) which means that once the first truss and a second truss are locked in position, there is little likelihood that the trusses can move out of alignment.

In use, the truss spacer is initially attached to a "first" truss on the ground, and in particular the attachment is by attaching connector 12 to the first truss while the truss is the on the ground. The grabbing jaw 13 is then pulled to the "open" position illustrated in figure 1. The truss can then be lifted (typically by a crane or similar) and generally into position on top of the walls.

Once the "first" truss is in position, the truss spacer will be "cantilevered" to one side of the first truss which is somewhat illustrated in figure 5 (although in figure 5 the first truss 39 is still shown on the ground but this is for illustration purposes only).

A "second" truss is then placed on the ground, and a "second" truss spacer is attached to the second truss whilst along the ground and in a manner similar to that described above. The second truss is then lifted into position and while still being lifted by the crane, the second truss can be pushed against the grabbing jaw 13 which is cantilevered from the first truss. When this occurs, the second truss will push against first jaw member 26 which will cause the ratchet mechanism to activate and, at some stage, will trigger the second jaw member to shoot to the locking position thereby locking the second truss in position.

As mentioned previously, the second truss contains its own "second" truss spacer and a "third" truss can have its own truss spacer attached to its prior to being lifted by the crane and the third truss can then press against the open grabbing jaw of the second truss until the grabbing jaw is triggered to clamp against the third truss.

This can be repeated with a fourth truss, fifth truss etc, until all the trusses are in position. When the process is complete, the various truss spacers can be removed and reused.

Referring now to the second embodiment illustrated in figures 13-14, this embodiment is very similar to that described above except that the grabbing jaw has a different triggering mechanism. Again, there is described a first jaw member 40 and a second jaw member 41, with second jaw member 41 being similar to the second jaw member 27 described above in that it can move between an open position (see figure 14) and a closed locking position (see figure 13), and a ratchet mechanism is provided. In this variation there is also provided an internal spring (not illustrated) which, when triggered, functions to push against connecting rod 42 which, in turn, will cause the second jaw member 41 to trigger to the clamping position. The internal spring is held against actuation by a trigger member 43, and trigger member 43 sits slightly proud of the first jaw member 40 (see figure 14) such that when the truss is pushed against first jaw member 40 it will first slightly depress trigger 43 (to the position illustrated in figure 13) and this will actuate the spring which will trigger the second jaw member to shoot to the clamping position illustrated in figure 13.

Figures 9-12 illustrate a truss controlling device which will be called a "truss grabber". The truss grabber 47 allows a person to manoeuvre a lifted truss (that is a truss that has been lifted by a crane for instance), and especially to manoeuvre the lifted truss to push against the grabbing jaw of an adjacent truss in the manner described above. The truss grabber contains a head portion 45 which is roughly channel shaped but which contains a pair of turned in portions 51 which are angled in a particular manner (see figure 10) to allow the grabber to grab an angled part of a truss 46 (for instance as illustrated in figure Figure 11 illustrates the other side of the truss 46, and shows the turned in portions 51. The head portion is attached to a universal socket arrangement 48 to provide great flexibility to the truss grabber. The socket arrangement 48 is, in turn, attached to a small extension piece 49 (see figure 12) and a long pole (not illustrated) can be attached to the bottom of extension piece 49 via a locking ring 50 (see figure 12).

Figure 23 illustrates the versatility of the truss spacer and especially how two or more spacers can be used to hold the first truss in a hip roof. To explain, In a normal installation of the first truss in a hip roof, the truss is mounted somewhere between 1 .8 3.6 m inwards of the end support wall. This means that the first truss must be stabilised by a series of temporary props mounted by the worker perched on the truss while the crane is still in control. Only after the first truss is secured can the remaining trusses be installed.

However, with the spacer of the invention refer to figure 23), a worker can stand on a ladder adjacent the end support wall and grab the top or bottom cord of the first truss with a modified truss spacer and thereby secure the truss to the end support wall.

The modified truss spacer unit) comprises the grabbing jaws 82 described previously, and the grabbing jaws 82 are attached to a long pole 80, 81 which can be length adjustable and will typically comprise a pair of poles that can be telescopically attached relative to each other and where the length of the pole can be locked using a locking device 83. Also, the poles can be hingedly attached relative to the grabbing jaws by any form of adjustable angle 84.

A series of these modified truss spacers (units) can be applied to various points on the truss including the top cord 85 and a bottom (ceiling) chord 86 to stabilise and plumb the truss. A variation in angle can be incorporated in the elongate to accommodate various truss heights and mounting points. The adjustment to the elongate (pole) can be a simple inner and outer sliding tube combination with a threaded or similar locking system 83. The securing and fixing to the end wall 87 is by way of utilising existing wall mounted cleats or by introducing a clamp or similar.

Referring now to figures 15 22, there is illustrated a truss spacer according to a third embodiment of the invention. In this embodiment, the truss spacer functions in a manner similar to that described with reference to figures 13 14. However, in this embodiment, the truss spacer does not have a ratchet system. Instead, springs are provided to provide the necessary force to retract the second jaw member from the cocked position (open) to the grabbing position (closed).

Referring to the illustrations, and initially to figures 15 17, the truss spacer 60 again contains an elongate arm member 61 (which is best illustrated in figure 20 and figure 21). A pair of jaw members is provided comprising a first jaw member 62 and a second jaw member 63. A difference in this embodiment is that first jaw member 62 does not move and is fixed in place relative to the remainder of the truss spacer. The second jaw member 63 can pivot between the closed grabbing position illustrated in figure 15 and the open cocked position illustrated in figure 16.

A trigger 64 is provided which comprises a plate like member positioned inside the first jaw member 62, the first jaw member 62 in the particular embodiment comprising a pair of spaced apart plates 65 (best illustrated in figure 18) such that trigger 64 can be positioned partially between the spaced apart plates 65 (also illustrated in figure 18). This is similar to that described with reference to figures 13 -14.

The truss spacer according to the third embodiment (figure 17 22) includes a guide track 66 positioned on each side of the truss spacer. Guide track 66 comprises a forward portion 67 which is generally "L-shaped" and therefore provides a locking position (this will be described below), and guide track 66 comprises a rear portion 68 (illustrated in figure 16 at least) which is not "L-shaped" but is more curved and rounded (the rear portion 68 has a more complex profile which is described in greater detail below).

Second jaw member 63 is again pivotally mounted in two spaced apart positions to pivot pins 69, 70, and pin 70 is attached to a slide member 71 which can function as a "pushrod" and, which in the particular embodiment, comprises a substantially Ushaped overhead bracket.

Slide member 71 contains a guide pin 73, and guide pin 73 slides along the guide track 66 between the rear position and the front position.

When the second jaw member 63 is in the closed position (figure 15), guide pin 73 is positioned in the rear portion 68 of the guide track 66. When the second jaw member 63 is lifted to the "cocked" position illustrated in figure 16, this causes the slide member 71 and guide pin 73 to be pushed forwardly causing guide pin 73 to be positioned in the forward L-shaped position 67 of the guide track 66. The second jaw member 63 can be moved manually to the cocked position (figure 16) and this can be done quite easily because of the "rounded" curvature of the rear portion 68 of guide track 66 (however it is necessary to initially lift slide member 71 to release it from the rather complicated profile of rear portion 68 and this will be described in greater detail below and with reference to figure 17). Movement of the second jaw member causes the guide pin 73 to move from the position illustrated in figure 15 to the position illustrated in figure 16.

Conversely, movement of the slide member/guide pin in the other direction will cause the second jaw member 63 to move to the grabbing position illustrated in figure However, because of the abrupt "L-shaped" configuration of the forward part 67 of guide track 66, when the guide pin 73 is in this forward part of the guide track, it is not possible to simply push the cocked jaw member (figure 16) back into the closed grabbing position (figure 15), as the guide pin 73 is "trapped" within the L-shaped configuration of the guide track.

The only way that the second jaw member 63 can move back to the grabbing position is by "lifting" the guide pin 73 slightly such that it moves out of the L-shaped front part of the guide track can also be called the secondary lock position).

The trigger 64 functions to provide the slight lifting action.

That is, when pressure is applied to trigger 64, an upward motion is generated rearward of the pivot to generate pressure on guide pin 73 to cause a slight lifting of the guide pin out of engagement in the L-shaped configuration.

A pair of springs 72 (illustrated in figure 18) is positioned within the truss spacer.

Springs 72 are "activated" when the second jaw member 63 is moved to the cocked position (figure 16), and therefore provide a strong bias or pushing force onto second jaw member 63 to push the second jaw member back into the closed grabbing position (figure 15). However, as long as guide pin 73 is trapped within the L-shaped portion 67 in the guide track 66, this cannot happen.

Upon pressing of trigger 64, a slight lifting action is provided onto guide pin 73 to lift the guide pin out of the L-shaped portion and, as soon as this happens, the springs will cause the jaw member 63 to shoot back to the closed position illustrated in figure Figures 20 21 show the truss spacer in the locked position.

Figure 17 illustrates that the rear portion 68 of the guide track 66 can have a more sophisticated profile and may comprise the rounded area 75 described previously, but also contains a second locking area 76. This can be seen as the primary and the secondary locking ramp. When the second jaw member 63 is in the grabbing position illustrated in figure 15, guide pin 73 is in the second locking area 76 and jaw member 63 cannot be simply pulled back to the open cocked in position. This provides a measure of safety against inadvertent opening of the second jaw member. Instead, it is necessary to slightly lift the slide member 71 (also known as the overhead bracket) The first jaw member 62 becomes part of the outer housing of the unit. The springs 72 will typically be under tension. The guide track 66 (see figure 17) has a primary and secondary 76 safety locking ramp system at the rear part of the track. As the guide pin 73 passes over these locking ramps, the inherent design of the unit causes the guide pin 73 to drop down to the primary 75 and then the secondary locking ramp 76 as motion continues. This secures the moving jaw 63 into a safe position. The slide member 71 transfers loaded to the locking pin during the opening motion forcing it to the bottom of the safety locking ramp. To open the moving jaw 63, the rear of the overhead bracket is lifted upwards to release the guide pin from the locking ramp and thereafter, the moving jaw can be moved to the open cocked position.

Throughout the specification and the claims (if present), unless the context requires otherwise, the term "comprise", or variations such as "comprises" or "comprising", will be understood to apply the inclusion of the stated integer or group of integers but not the exclusion of any other integer or group of integers.

Throughout the specification and claims (if present), unless the context requires otherwise, the term "substantially" or "about" will be understood to not be limited to the value for the range qualified by the terms.

It should be appreciated that various other changes and modifications can be made to any embodiment described without departing from the spirit and scope of the invention. For instance, the spacer may be manufacture of materials of low cost, to enable the spacer to be a single use spacer, and therefore left in place on the trusses and not retrieved.

Claims (14)

1. A spacer apparatus to enable a pair of trusses to be held relative to each other, the apparatus comprising an elongate member adapted to extend at least between a pair of adjacent trusses in use, a connector on the elongate member to enable the apparatus to be attached to a first truss prior to the first truss being lifted into position, and a grabbing jaw on the elongate member and spaced from the connector, the grabbing jaw having a first jaw member and a second jaw member and being operable between a clamping position to clamp against a second truss, and a release position, biasing means to bias the grabbing jaw to the clamping position, and a trigger to cause the grabbing jaw to move from the release position to the clamping position.

2. The apparatus as claimed in claim 1, wherein the elongate member comprises a box section having a length of between 0.5-3 m.

3. The apparatus as claimed in any one of the preceding claims, wherein the connector is mounted to the elongate member in an adjustable manner and is able to be clamped and released relative to the elongate member.

4. The apparatus as claimed in any one of the preceding claims, wherein the connector is mounted adjacent one end of the elongate member.

The apparatus as claimed in any one of the preceding claims, wherein the connector comprises a first side wall and a second side wall which are spaced apart sufficiently to enable a part of the truss to be positioned between the first side wall and the second side wall.

6. The apparatus as claimed in claim 5, including a releasable locking means to releasably lock the connector to the truss to prevent the connector from being inadvertently released from the truss.

7. The apparatus as claimed in any one of the preceding claims wherein the grabbing jaw comprises a body member adapted for attachment to the elongate member and able to be releasably locked thereto, a ratchet mechanism attached to the body member, and a rack which is attached to the first jaw member.

8. The apparatus as claimed in claim 7, wherein the second jaw member is attached to the body member and is also attached relative to the first jaw member with an over centre mechanism.

9. The apparatus as claimed in claim 8, wherein the first jaw member is able to be pushed relative to the body member to cause the second jaw member to trigger from the free position to the clamping position.

The apparatus as claimed in any one of claims 1-6 wherein the first jaw member of the grabbing jaw is associated with the trigger, the grabbing jaw further including a spring adapted to move the second jaw member from the free position to the clamping position, the trigger functioning to actuate the spring.

11. The apparatus of any one of the preceding claims, wherein the trigger is operated by pushing part of the truss against the first jaw member.

12. The apparatus of any one of claims 1-11, wherein the biasing means is a spring, the spring being held against actuation to the jaw clamping position by the trigger, the trigger being a separate member which is positioned slightly proud of the first jaw member such that when a truss is pushed against first jaw member it will contact the trigger which actuates the spring to move the second jaw member to the clamping position.

13. A method of erecting trusses comprising attachment of a spacer apparatus according to any one of the preceding claims to a first truss, placing the first truss in position, attaching a further spacer apparatus to a second truss, lifting the second truss, manoeuvring the second truss such that the second truss engages the grabbing jaw of the spacer apparatus and triggers the second jaw member to clamp against the second truss, placing a further spacer apparatus onto a third truss, lifting the third truss, manoeuvring the third truss such that the third truss engages the grabbing jaw on the second truss to trigger the grabbing jaw on the second truss to clamp against the third truss and repeating the process as many times as necessary until all, or substantially all the trusses are in place.

14. A spacer apparatus substantially as hereinbefore described with reference to the accompanying illustrations. DATED 30 MARCH 2007