WO2002055270A1

WO2002055270A1 - Collapsible trestle type support structure

Info

Publication number: WO2002055270A1
Application number: PCT/AU2001/000024
Authority: WO
Inventors: Darryl Glen Harpley; Terry Reginald Godde
Original assignee: Darryl Glen Harpley; Terry Reginald Godde
Priority date: 2001-01-10
Filing date: 2001-01-10
Publication date: 2002-07-18

Abstract

A trestle like support structure comprises an elongate carrier beam, with a pair of support legs mounted to each end of the beam. The two pairs of support legs are mounted to the beam by a first and second pivot assemblies. The first pivot assembly enables a pair of legs to pivot between a first position in which the two legs are substantially parallel to the beam, and a second position in which the two legs are perpendicular to the beam. The second pivot assembly enables the pair of legs to pivot relative to each other from a generally parallel position to a splayed position. When the legs are erected and splayed they are secured against collapse, thereby providing a strong and stable work platform.

Description

Collapsible Trestle Type Support Structure

Field of the invention

This invention relates to collapsible trestles suitable for use as work benches, saw horses, work surfaces or the like. Background of the invention

Collapsible work benches are frequently used by a wide variety of tradesmen. In such work benches, one or more pairs of legs is usually pivotally secured to a beam via a bracket assembly such that the legs may be moved between a folded position and a strong, secure and stable upright position. The work bench may therefore be used by the tradesman when the legs are in the upright position supporting the beam, and when the tradesman no longer requires the work bench, the legs may be folded to be substantially parallel with the beam to enable the convenient storage of the work bench.

A common problem with such collapsible structures is the stability of the structure when in use. Many known prior structures are prone to wobble or yield somewhat when a force is applied to them or a weight is supported on them.

In order to overcome such stability problems, structures have been proposed which are strongly reinforced but which are therefore heavy, cumbersome and expensive. Typically, such structures include braces extending between the legs of the work bench and frequently between the legs and the beam itself. This additional reinforcing structure prevents known collapsible work benches from being folded into a neat and compact package for convenient transportation and storage. The structures are often difficult to collapse.

It is an object of the present invention to provide a trestle or like structure which forms a structurally stable trestle when the legs are in an erected position but which forms a compact unit when collapsed. Summary of the invention

According to the invention there is provided a trestle like support structure comprising: an elongate carrier beam, a pair of support legs mounted to each of the ends of said beam, each pair of legs being mounted to the beam via first and second pivot assemblies; the first pivot assembly being adapted to enable the pair of legs to pivot between a first position in which the two legs are substantially parallel to the beam and a second position in which the legs are generally perpendicular to the beam; the second pivot assembly being adapted to enable the pair of legs to pivot relative to each other from a generally parallel position to a relatively splayed position; and stop means preventing the legs moving angularly apart from each other beyond said splayed position. Preferably the support beam comprises an inverted generally U-shaped channel section having a web and parallel flanges and the two pairs of legs nest between the flanges when in said first position. The legs may be locked in their second position when they are splayed relative to each other. The legs are preferably biased relative to each other towards said splayed position. The said second pivot assembly may comprise a single pivot pin aligned generally parallel to the length of the carrier beam. Each of said flanges may have an inwardly directed lip on the distal ends thereof and the lips on each end of the beam are removed to define an enlargened opening at each end of the beam, the legs, when in said second position being adapted to move into said enlargened opening as they pivot into said splayed position. The lips adjacent the enlargened opening prevent the legs moving from said second position to said first position when the legs are in said splayed position. The distal edges of said flanges in said enlargened opening may define said stop means.

Each pair of legs may be mounted to a generally cylindrical bracket, the cylindrical bracket being pivotable relative to the beam about a pivot axis which is operatively horizontal and perpendicular to the length of the beam. The cylindrical bracket may be part non-circular, part circular, in cross-section with the non circular part acting as a stop for the legs when pivoting into said second position. The second pivot assembly may comprise a pivot hole through said bracket which is perpendicular to said pivot axis, and a fastener which passes through the legs and through the pivot hole to thereby pivotally connect the legs to the bracket. A support structure may have a work surface secured to the beam.

The work surface may be secured to the beam by means of a pair of elongate brackets formed of a generally L-shaped section which are secured to opposite sides of the beam.

Preferred arrangements of the present invention are depicted in the accompanying drawings, but those drawings are not to be understood as illustrating the only possible form or arrangement of the various features which make up the apparatus according to the invention.

Brief description of the drawings

FIG. 1 is a perspective view of a collapsible trestle or work bench according to the present invention; FIG. 2 is a perspective cut-away view of a portion of the collapsible work bench of FIG. 1 ;

FIG. 3 is a plan view from under the collapsible work bench of FIG. 1 when the legs supporting the work bench are in a folded position;

FIG. 4 is a plan view from underneath the work bench of FIG. 1 when the legs supporting the work bench are in an extended position; FIG. 5 is an end view of one embodiment of a bracket for connecting a pair of legs to a beam according to the present invention with the legs in an extended position;

FIG. 6 is an end view of a bracket for connecting a pair of legs on a beam of FIG. 5 but with the legs in a folded position;

FIG. 7 is a side view of a bracket for connecting a pair of legs on a beam as shown in FIG. 5; FIG. 8 is a side view of a bracket for connecting a pair of legs on a beam as shown in FIG. 6;

FIG. 9 is a plan view of one embodiment of a blank used to form one of the legs;

FIGS.10A and 10 B show side and end elevations of a solid bracket for connecting the legs to the beam; and

FIG. 11 shows a partly exploded perspective view of a trestle and work surface. Detailed description of the embodiments

Referring to the drawings, a trestle type workbench 1 is shown comprising a beam 2 which is supported on two pairs of legs, numbered 3, 4, 5 and 6 respectively. The legs are connected to the beam 2 by means of a cylindrical bracket 14 which is described in more detail below. The beam 2 includes an inverted channel shaped section 8 which is comprised of a web 10 and parallel flanges numbered 11 and 12.

Each pair of legs is pivotable relative to the beam 2 about a pivot axis indicated by dotted lines 15. The legs are pivotable between an erected condition as shown in figure 1 in which the legs are generally perpendicular to the beam 2, and a folded condition, as shown in figure 3 in which the legs are parallel with the beam 2 and nest between the flanges 11 and 12, against the underside of the web 10.

The individual legs in each pair of legs are also pivotable relative to each other about a pivot axis 16. The legs are only pivotable about axis 16 when in their erected condition, that is, when the legs are perpendicular to the beam 2. When the legs are in this erected condition they are able to pivot about the axis 16 between a position in which the legs are basically parallel with each other and a position in which the legs are angularly splayed. Figure 5 indicates the manner in which the legs 3 and 4 are pivotable relative to each other. Each pair of legs is provided with a spring 9 which urges the legs into their splayed condition. The spring 9 is coiled around a pin 17 about which the legs are pivotable relative to the bracket 14. The pin 17 is thus coaxial with the axis 16.

The channel 8 includes a pair of inwardly directed lips numbered 18 and 19 formed on the distal edges of the flanges 11 and 12. It will be noted that at each end of the beam 8, the lips 18 and 19 have been removed from the beam 8 to create an enlarged opening numbered 20 and 21 in the drawings. Openings 20 and 21 provide a gap into which the legs can move as they move from the parallel position to the splayed position, indicated in figure 5. The ends of the lips 18 and 19 define an abutment edge 22 against which the legs will bear when the legs are in their splayed positions to prevent the legs collapsing towards the centre of the beam when the legs are in their splayed position. Thus, as the legs move into the splayed position they abut against the abutment edges 22, thereby locking the legs in their erected position preventing the trestle collapsing if a lateral load is applied to the trestle.

In addition, the edges 23 of the flanges 11 and 12 in the openings 20 and 21 engage with the outer surface 24 of the legs to thereby prevent the legs splaying open beyond a selected angular separation. The edges 23 thus serve as a stop formation and the spring means 9 urges the legs against that stop formation, thereby once again holding the trestle in a stable condition when the legs are erected and splayed.

An alternative form of bracket 14 is shown in figure 10 of the drawing. The bracket 14 has a generally cylindrical shape with one side 25 of the cylindrical shape being of circular or arcuate form which allows the bracket to rotate with the legs as the legs move between their folded position, shown in figure 3, and their erected position shown in figure 7. The bracket 14 also includes a non-circular portion 26 which abuts against the underside of the web 10 when the legs are in their erected position. This is best shown in Figure 7. The bracket 14 thus serves to prevent the legs moving beyond a substantially vertical position when the legs are erected, thereby, once again, holding the trestle in a stable condition when the legs are erected.

The bracket 14 is preferably machined from a solid block of material such as steel or aluminium and is notched as indicated so as to engage with corresponding formation formed on the underside of the U-shaped section channel 8. This ensures that when the legs are in their erect position the bracket 14 positively engages with corresponding formations on the underside of the channel 8 to thereby lock and stabilise the legs in that position ensuring stability and rigidity for the overall structure.

Some of the notches in the bracket 14 are designed to engage with the legs when the legs are in their splayed position and the depression 14' engages with a dimple in the underside of the web portion of the channel 8.

It is envisaged that the overall product will be approximately 1 metre in length, that is, the beam 2 will be 1 metre in length and will stand 680mm high when unfolded. The length extension will increase the height of the trestle by 200mm. It is envisaged that the channel section will be formed of 1mm thick steel and the legs will be formed of 2mm thick steel. Of course, other materials are possible and a light weight trestle could be formed of aluminium or thinner steel section. It is envisaged that a trestle as described above without extended legs will be capable of safely supporting a load of 250 kg.

It will also be noted from figure 5 that the top edges 27 of the legs engage against the underside of the web 10 when the legs are in their splayed condition. This arrangement, once again, ensures that the interaction between the beam and the legs is such that the legs are stable and rigidly connected to the beam when in their erected and splayed position.

It will be appreciated that to collapse the trestle all that will be required is to move the two legs into parallel relationship with each other and then fold the legs inwardly between the flanges 11 and 12. The lips 18 and 19 will ensure the legs do not inadvertently fall out of the gap between the two flanges during transportation of the structure.

It will be possible to mount any suitable work surface onto the upper side of the channel 8. As shown in figures 1 to 9, a relatively narrow wooden work strip 7 has been fixed to the operatively upper side of the channel 8. Figure 11 indicates a different arrangement. In figure 11 a work surface 28 is shown which is mounted to the channel 8 by means of a pair of brackets 30 which are secured to the channel 8 by means of fasteners 31 which are preferably hand tightenable nut and bolt assemblies. The work surface 28 will serve as a work bench or work table and clearly, if required, a larger table surface could be affixed to the channel 8. The work surface 28 has a handle opening 32 in one side thereof to facilitate carrying of the structure when the legs are folded into the gap between the flanges 11 and 12.

As also shown in figure 11, the legs 3 to 6 may have extension legs 33 securable thereto to enable the height of the structure to be increased. The extension legs 33 preferably clip into notch formations formed on the legs 3 to 6 to allow for simple raising of the structure.

There may be many variations to the above described embodiment without departing on the scope of the invention. However, it is considered that a simple trestle which is easy to erect and, once erected is stable is provided by a simple double pivot arrangement as described herein. Different brackets and pivot arrangements are possible without departing from the scope of the invention. For example, it would be possible for each leg of each pair of legs to be connected to the bracket 14 by a separate pivot pin arrangement. Also, the bracket 14, may take on various different forms and configurations without departing from the scope of the invention.

It will be understood that the invention disclosed and defined herein extends to all alternative combinations of two or more of the individual features mentioned or evident from the text or drawings. All of these different combinations constitute various alternative aspects of the invention. The foregoing describes embodiments of the present invention and modifications, obvious to those skilled in the art can be made thereto, without departing from the scope of the present invention.

Claims

1. A trestle like support structure comprising: an elongate carrier beam, a pair of support legs mounted to each of the ends of said beam, each pair of legs being mounted to the beam via first and second pivot assemblies; the first pivot assembly being adapted to enable the pair of legs to pivot between a first position in which the two legs are substantially parallel to the beam and a second position in which the legs are generally perpendicular to the beam; the second pivot assembly being adapted to enable the pair of legs to pivot relative to each other from a generally parallel position to a relatively splayed position; and stop means preventing the legs moving angularly apart from each other beyond said splayed position.

2. A support structure according to claim 1 wherein the support beam comprises an inverted generally U-shaped channel section having a web and parallel flanges and the two pairs of legs nest between the flanges when in said first position.

3. A support structure according to either preceding claims wherein the legs are locked in their second position when they are splayed relative to each other.

4. A support structure according to claim 3 wherein the legs are biased relative to each other towards said splayed position.

5. A support structure according to any preceding claims wherein said second pivot assembly comprises a single pivot pin aligned generally parallel to the length of the carrier beam.

6. A support structure according to claim 2 wherein each of said flanges have an inwardly directed lip on the distal ends thereof and the lips on each end of the beam are removed to define an enlargened opening at each end of the beam, the legs, when in said second position being adapted to move into said enlargened opening as they pivot into said splayed position.

7. A support structure according to claim 6 wherein the lips adjacent said enlargened opening prevent the legs moving from said second position to said first position when the legs are in said splayed position.

8. A support structure according to claim 7 wherein the distal edges of said flanges in said enlargened opening define said stop means.

9. A support structure according to claim 8 wherein spring means biases the legs into said splayed position.

10. A support structure according to any preceding claim wherein each pair of legs is mounted to a generally cylindrical bracket, the cylindrical bracket being pivotable relative to the beam about a pivot axis which is operatively horizontal and perpendicular to the length of the beam.

11. A support structure according to claim 10 wherein the cylindrical bracket is part non- circular, part circular, in cross-section with the non circular part acting as a stop for the legs when pivoting into said second position.

12. A support structure according to claim 11 wherein said second pivot assembly comprises a pivot hole through said bracket which is perpendicular to said pivot axis, and a fastener which passes through the legs and through the pivot hole to thereby pivotally connect the legs to the bracket.

13. A support structure according to any preceding claims having a work surface secured to the beam.

14. A support structure according to claim 13 wherein the work surface is secured to the beam by means of a pair of elongate brackets formed of a generally L-shaped section which are secured to opposite sides of the beam.

15. A support structure substantially as hereinbefore described with reference to the accompanying drawings.