AU2002300535B2 - Plank Support Stand - Google Patents

Description

1

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT Plank Support Stand The following statement is a full description of this invention, including the best method of performing it known to me: The invention relates to a plank support stand. More particularly, though not exclusively, the invention relates to structures used to support planks upon which tradespersons can walk. Such stands might be useful to plasterers, painters, bricklayers or other tradespersons or home handypersons.

Known plank support scaffolds comprise a trestle or other frame erected at or near respective end portions of a plank or planks. Step ladders can be used at either end of a plank to support the same in a raised horizontal orientation to enable a person to sit and/or stand upon the plank to work. Some scaffold structures include lengths of tubing to be inter-engaged to form a stable structure.

The above-described known structures suffer from instability and are time-consuming to erect. Also, such structures are often large and cumbersome, not lending themselves well to transportation in the trunk of a motor vehicle.

Accordingly, it is the object of the present invention to overcome or substantially ameliorate at least one of the above disadvantages and/or more generally to provide an improved plank support stand.

The present invention resides in a plank support stand including support legs, and a plank support head connecting the legs for supporting one or more planks in a generally horizontal orientation, said plank support head including clamping means for clamping said one or more planks and means for actuating said clamping means so as to fix the plank to said stand.

2 Preferably, the plank support stand comprises a single pair of said legs, each having a stabilising foot.

Preferably, one of said pair of legs is substantially vertical and the other of said pair of legs is inclined, at least one said leg having one or more step members for user access to said supported planks.

In one form, the plank support head includes a hinged member connecting said legs, said hinged member having said clamping means, and means for causing hinging of said hinged member such that the clamping means clamps against opposed edge portions of the plank. Preferably, the means for hinging includes means bearing against an underside of said plank to urge closing of said hinged member against the plank edge portions.

In a further form, the plank support head includes a cross rail extending between said legs, at least an opposed pair of end clamps mounted on said rail and wherein said clamp actuating means urges said end clamps to engage edges of said plank.

The plank support head may further include one or more intermediate clamps mounted on said rail, and may further include means for causing one or more said intermediate clamps to pull down on said planks.

In one preferred form, the clamp actuating means includes lever means mounted to said rail, said lever means being connected to one of said end clamps to actuate said clamping.

Preferably, the lever means includes a lever having a first pivotable connection to a clamp actuating rod, a second pivotable connection which travels along a mounting slot transverse to the actuating rod, and means for causing said travel along the mounting slot to cause axial movement of said actuating rod.

In an alternative form, the clamp actuating means includes gear means mounted within said rail, said gear means being connected to one of said end clamps to actuate said clamping. Preferably, the gear means comprises a pinion driving a rack which is connected to said end clamp.

Preferred forms of the present invention will be described by way of example with reference to the accompanying drawings, wherein: Fig. 1 is a front elevation view of a stand according to a first embodiment of the present invention; Fig. 2 is a detail of the head portion of the stand of Fig. 1; Fig. 3 is a plan view of the stand head portion of Fig.2; Fig. 4 is a cross-section of the portion shown in Fig.2, taken along line 4-4; Fig. 5 illustrates a wider plank secured by the stand of Fig. 2; Fig. 6 is a front elevation view of a stand according to a second embodiment of the present invention; Fig. 7 is a detail of the head portion of the stand of Fig. 6; Fig. 8 is a plan view of the clamp drive cam lever mechanism of the stand shown in Fig. 6; Figs. 9A to 9C show the clamp drive arrangement of Fig. 6 in a series of successive positions between an unclamped configuration and a clamped configuration; Figs. 10 and 11 are front elevations of a variant of the stand shown in Fig.6, with an additional plank pull-down mechanism; Figs. 12, 13 and 14A to 14C illustrate an alternative cam lever arrangement for the stand of Figs. 6 to 11; Figs. 15 and 16 are front elevations of a multiple plank clamping arrangement employing a gear drive; Figs 17 and 18 are, respectively, plan and elevation views of a gear drive and locking arrangement for the embodiment of Figs. 15 and 16; and Figs 19 and 20 illustrate engagement of locking formations on the clamp and the plank.

'L 4 Referring now to the drawings, there is illustrated in Figs. 1 5 a plank support stand according to a first embodiment of the present invention. The illustrated plank support is adapted to co-operate with one or more similar stands at spaced locations along the length of the plank, to support the plank in a generally horizontal orientation.

In this embodiment, stand 10 includes a single pair of collapsible, telescopic legs 12 connected at their tops by a plank support head 15. A stabilising foot 13 is provided at the bottom of each leg 12, and a telescopic cross-brace 14 extends between the legs 12 for additional rigidity.

The plank support head 15 consists of a pair of plates 11 joined by a central hinge 17, each plate being rigidly affixed to the upper end of a respective leg 12, for example by welding or bolting. The edge portion of each plate 11 of head 15 has a plank clamping portion 23 which clamps the opposed edges of the plank 22, with an inturned lip 16 which fits over the edge of the plank to prevent to limit upwards movement of the plank.

A tensioning arrangement is provided, comprising a threaded passage, formed by a nut attached to the centre of the hinge, through which passes a bolt 18 to which is affixed a plank engagement plate 21. The bolt has a winged head 19.

In use, a plank will be fitted into the stand, either by sliding the stand onto the edge of the plank or by opening up the angle of the hinged cross-member and inserting the plank from above, and the legs of the stand frame are then moved apart to bring the clamping portions of the cross-member to bear against the edges of the plank.

Tightening of bolt 18 by manipulation of the winged head 19 causes the engagement plate 21 to move upwardly against the undersurface of the plank 22 and urges the plank against the underside of the lips 16. Further tightening pushes the hinge line of 1 ".j the cross-member 15 down, decreasing the angle between the two plates and firmly clamping the edges of the plank.

The cross-brace 14 is then adjusted and tightened to stiffen the frame.

As apparent from comparison of Fig. 2 with Fig. 5, the illustrated plank support is adapted to accommodate planks of different widths.

To remove the plank, the cross-brace is disconnected and the bolt 18 loosened to allow the plank 22 to be lifted or slid out. The legs can be swung to a generally parallel position and telescoped down to their shortest length, to minimise the space required for transport and storage. Because each frame has just a single leg on each side, with the stabilising feet being removable if required, the units stack efficiently in the back of a vehicle or at a storage shed.

In Figs. 6 to 9C of the accompanying drawings there is schematically depicted a plank support stand 30 according to a second embodiment of the present invention. This stand may support either a single plank (see Fig. 6) or multiple planks in side-by-side orientation (Fig. 7).

In common with the first embodiment, the stand of Figs. 6-9C also has a single pair of legs 12a and 12b with plank support head 25 and a cross-brace 14 extending therebetween. Stand 30 includes one vertical leg 12a and one outwardly angled leg 12b, so that the stand may be positioned close against a wall (not shown) while maintaining sufficient stability in the direction transverse to the plank. Stabilising feet 13 provide stability in the direction parallel to the plank. Legs 12a, 12b are telescopically adjustable to allow adjustment of the height of the platform to be formed, while one or both of the legs, preferably the inclined leg 12b, has step treads 24 thereon.

In an unillustrated embodiment, the stand may further provide means for attachment of handrail support at one or both sides of the stand.

6 Referring to Figs. 7 to 9C, the plank support head 25 comprises a fixed length tubular cross beam 27 extending between the upper ends of the legs 12a, 12b, which acts as a rail for slidable mounting blocks carrying a pair of generally C-shaped plank edge clamps 29, and a clamp drive mechanism. As shown in Fig. 7, a one-plank system can be extended to accommodate two or more planks by adding similarly-mounted Ishaped intermediate clamping members 28.

In the embodiment of Figs. 6 to 9C, the clamp drive mechanism consists of a pullrod 39 mounted through the clamp mountings 38 under the cross-beam, actuated by the lever arrangement illustrated in detail in Figs. 8 and 9A to 9C.

Figs. 9A to 9C is a series of front elevations showing operation of the cam lever clamp drive mechanism from the unclamped position (Fig. 9A) to the clamped position (Fig.

9C). The lever mechanism includes a lever mounting box 48 fixed to the bottom of the rail 27, having a generally vertical slot 50 which slidably receives the end pivot pin 52 of an L-shaped clamp actuating lever 43. The lever has a further pivotable mounting pin 54 at its elbow, connected to the end of the pullrod 39. As the lever handles 45 are depressed, the pullrod is pulled to the right (as shown), which in turn brings the left end clamp 29 across to engage against the edge of the plank (not shown). The mounting for the right end clamp bears against the lever mounting box 48, thus clamping the plank or planks between the two end clamps, held down by their engagement under the top flanges of the end clamps and, where applicable, the intermediate clamp 28 (Fig. As may best be seen in Fig. 9C, the top of the guide slot 50 ends above the axis of the pullrod, so that clamp is held in the clamped position by overcentering of the lever.

Preferably, the recesses of the C- and I-clamps which receive the edge of the plank are tapered, for example as shown in Fig. 7, to provide a tight engagement with the plank edge.

To unclamp the planks for removal, the user lifts the lever handles 45. Compression spring 40 assists return of the far left end clamp to the unclamped position Figs. 10 and 11 illustrate a variation on the embodiment of Figs. 6 to 9C, further include an intermediate clamp with a pull-down mechanism. The mounting blocks 37, 38 of the two end clamps 29 have downward extensions, to which are pivotably connected linkages 33, 34 to a vertical pullrod 35 which carries the top flanges 15 of the intermediate clamp. As the clamping lever is actuated, reducing the distance between the two end clamps, the top flangesl5 are pulled down to bear against the planks. Thus, the planks are simultaneously clamped from the top and from the sides.

The compression spring 40 serves to release both the top and side clamping upon release of the clamping lever.

In the construction of Figs. 10 and 11, the end clamps may be simply an L-section, or have only a small top flange, for improved ease of installing and removing the planks.

Figs. 12 to 14C show an alternative clamping lever arrangement for the plank stand of Figs. 6 to 11. In this embodiment, the far side end clamp is fixed while the near side end clamp moves with the pullrod 39. The lever mounting box 48 is similar to that in Figs. 12 to 14C, with the L-shaped lever replaced by a pivotable link 57 with a handle 58. As the handle is lifted, the link pivots to near horizontal, pushing the end clamp across into engagement with the edge of the plank. Pressing down the handle will release the clamp.

Figs. 15 to 18 show a head arrangement adapted for multiple planks, incorporating a rack and pinion gear clamp drive located inside the tubular beam 27. The clamp drive includes a pinion gear 60 actuated by a drive handle 62, the pinion meshing with a rack 63 attached to the near side end clamp. The far side end clamp is fixed, while the intermediate clamps are attached to the mounting of the near side end clamp by a pull rod 39 to assist plank release.

The arrangement includes a pawl 64 for preventing accidental unclamping of the plank support by allowing rotation of the pinion in the clamping direction only when the pawl is engaged. The pawl may be external to the tubular beam, engaging an external ratchet gear 66 linked to the drive pinion, as shown in Figs 15 and 16, or alternatively may be attached to the pivot axis of a handle 68, directly engaging the pinion inside the tube as shown in Figs. 17 and 18.

Figs. 19 and 20 are, respectively, plan and cross-section views of a clamp and plank construction including a plurality of complementary locking formations in the clamp 29 and plank 22. The plank 22 has a series of notches 70 along its length, which receive matching Jugs 72 inside the C-shaped clamp 29. Such formations assist locking of the plank in the clamp, and is especially advantageous where the stand is to be used at the end of a plank, for example at the junction of two planks laid end-toend, as illustrated in Fig. 19.

In this specification, the word "comprising" is to be understood in its "open"~ sense, that is, in the sense of "including", and thus not limited to its "closed" sense, that is the sense of "consisting only of'. A corresponding meaning is to be attributed to the corresponding words "comprise, comprised and comprises" where they appear.

While particular embodiments of this invention have been described, it will be evident to those skilled in the art that the present invention may be embodied in other specific forms without departing from the essential characteristics thereof. The present embodiments and examples are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

It will further be understood that any reference herein to known prior art does not, unless the contrary indication appears, constitute an admission that such prior art is commonly known by those skilled in the art to which the invention relates.

Claims (10)

1. 2. A plank support stand according to claim 1, comprising a single pair of said legs.
2. 3. A plank support stand according to claims 1 or 2, wherein each said leg has a stabilising foot.
3. 4. A plank support stand according to any one of claims 1 to 3, wherein at least one said leg has one or more step members for user access to said supported planks. A plank support stand according to any one of claims 1 to 6, wherein said means for hinging or said hinged member includes means bearing against an underside of said plank to urge closing of said hinged member against the plank edge portions.
4. 6. A plank support stand according to any one of claims 1 to 5, wherein said clamping means includes a substantially C-shaped section to engage an edge of the plank.
5. 7. A plank support stand according to claim 6 wherein said C-shape is tapered so as to tighten against upper and lower surfaces of the planks when said clamping is actuated.
6. 8. A plank support stand according to any one of the preceding claims, wherein one or more intermediate clamps are utilised employing substantially an I-shaped section to engage edges of two adjacent planks.
7. 9. A plank support stand according to claim 8, including means for causing one or more said intermediate clamps to pull down on said planks. A plank support stand as claimed in any one of the preceding claims wherein means to urge said support legs apart is provided.
8. 11. A plank support stand as claimed in claim 10 wherein said means to urge includes a telescoping means. C02065 S 12. A plank support stand as claimed in claims 10 or 11, wherein said one or more planks ,I will limit movement apart of said support legs.
9. 13. A plank support stand as claimed in any one of the preceding claims wherein said hinged member allows said one or more planks to be positioned therein from above and or the side. tV 14. A plank support stand according to any preceding claim, wherein said clamping means V) includes one or more locking formations which engage with complementary formations on said plank. ¢c, C 15. A plank support stand as claimed in any one of the preceding claims wherein said clamping means urges said one or more planks in a vertical direction to clamp against a lip of said clamping means.
10. 16. A plank support stand as herein described, with reference to any of the accompanying drawings. Dated this 5thth day of October 2007 Bradley John Reinhard by its patent attorneys HALFORD CO