GB2198070A

GB2198070A - A workbench for an inclined surface

Info

Publication number: GB2198070A
Application number: GB08728421A
Authority: GB
Inventors: Christopher Peter Hawkins
Original assignee: Individual
Current assignee: Individual
Priority date: 1986-12-05
Filing date: 1987-12-04
Publication date: 1988-06-08
Also published as: GB8907521D0; GB2218373A; GB8728421D0

Abstract

A workbench (11) comprises a working platform (12) mounted on a support frame comprising adjustable legs (18, 19, 20, 21) at least two of which (18, 19) are telescopically adjustable to enable the bench to be supported on an inclined surface such as a roof. Gripper feet (24) pivotally mounted to the ends of the legs enable the bench to be secured to battens (33, 34) of a roof and these can be clamped in place to hold the workbench securely. Pivots (22, 23) allow the working platform (12) to be adjusted in inclination with respect to the leg frame (18, 19, 20, 21) and a bracing strut (38) with a clamp (42) secures the platform (12) in the desired orientation. A vice (45) and slate-guillotine (46) may additionally be provided. Rollers may be provided on the feet 24 for moving the workbench along the roof battens. <IMAGE>

Description

A WORKBENCH FOR AN INCLINED SURFACE The present invention relates generally to a workbench for an inclined surface, and particularly to a workbench which is able to be used on a steeply inclined surface such as a pitch roof.

During the construction of pitch roofs it is frequently necessary to perform operations on the roof cladding elements or other parts of the roof structure which require a secure working surface for which reason it has in the past been necessary to return from the sloping roof surface to a horizontal surface, for example, of a tower platform or scaffolding, to perform these operations.

Continual commuting between a work point on the sloping roof and a work bench on the scaffolding constitutes a considerable waste of time and therefore detrimentally affects the cost of construction of the roof both from the waste of an artisan's time in moving from one place to another (first order effect) and the increase in fatigue due to the unnecessarily wasteful effort this involves (second order effect). However, until now such commuting has been unavoidable since, for example, slate cutting or shaping operations which require a secure horizontal surface or a vice, could not be performed in situ because it was impossible to work on the slate on the inclined roof surface.Although the much-acclaimed portable work benches which have been introduced of recent years have ameliorated this problem by making it possible to set up a temporary work station on the scaffolding, rather than, as had previously been necessary, returning to the ground to perform such operations, there is still quite a considerable time and effort wasted in moving to and from such a work bench.

The present invention seeks to overcome this problem by providing a work bench which can be set up on an inclined surface, such as the inclined surface of a roof under construction, and provide a secure horizontal, or if appropriate, inclined, working platform on which the necessary operations on roof cladding elements and the like can be performed conveniently and in safety.

According to one aspect of the present invention, therefore, a workbench for an inclined surface having a working platform supported on a collapsible frame having two pairs of legs, the legs of at least one pair of which are longer than the others such that the working platform is held substantially horizontally or at a selected inclination when the workbench is placed on an inclined surface.

Preferably, the legs of one pair thereof are adjustable in length whereby to adjust the inclination of the working platform with respect to a support surface on which the work bench is placed.

This allows the work bench to be adjusted to accommodate various different inclinations to which roof structures are conventionally constructed. Although it would be possible to make the telescopic legs infinitely adjustable over a given range, because roof constructions traditionally are limited to relatively fixed angles, it may be found sufficient for the adjustment to be limited to two or three different positions, say at 321/20, 371/20 and 450.

According to another aspect of the present invention a workbench for an inclined surface has a working platform supported on a collapsible frame having two pairs of legs one pair of which is adjustable to be made longer than the other with the working platform substantially horizontal when the workbench is placed on an inclined surface, in which there are provided feet at the lower end of at least one pair of legs, incorporating rollers allowing the workbench to be moved in at least one direction by rolling thereon.

This facilitates movement of the workbench along a roof since, if the rollers are provided with associated guide means, the bench can be rolled along a batten or pair of adjacent or otherwise parallel battens from one work point to another. In this respect it will be appreciated that the battens for receiving slates must already be positioned with a high degree of parallelism in order to ensure that the lines of slates are parallel, this being an important visual aspect of a roof.

In the preferred embodiment of the invention the ends of the legs are provided with engagement means for engaging against ridges or other surface asperities on an inclined surface on which the workbench may be positioned. For this purpose the end of at least one of the legs may have a gripper foot which can be actuated to grip a fixed part of an inclined surface whereby to retain the workbench in position on such inclined surface. The said gripper foot may, for example, comprise a clamping member having screw operated or other clamping means.Of course, although the minimum requirement is for only a single leg to be provided with such gripper means, it is preferable for two or more such legs to be so provided in order to ensure that the workbench is securely locked in position on the inclined surface for resisting any turning movements which may be imparted to the working platform of the workbench during use. In embodiments of the invention having roller feet, the gripper or clamp means may be provided in addition to the rollers for clamping onto upstanding ribs or battens. The feet may be provided on all four legs and are conveniently in the form of generally U-shape members having the roller located in the bight portion thereof.

For use on rough or irregular ground all four legs may be independently adjustable so that inclined surfaces of an irregular nature as well as the regular inclined surfaces of roofs may be accommodated. For example, when building roofs having dormers or other inclined pitches it may be convenient to be able to position the workbench at the junction between two roof planes and in this case two identical pairs of legs may not provide the required degree of adaptability for the workbench to be positioned conveniently.Likewise, it may be required to use the workbench in other locations (either on horizontal or Inclined surfaces) and in such circumstances ae least -cwo of tihe legs may use provided with means for inserting the tip portion thereof into soft ground.

In embodiments in which a gripper foot is provided at the end of at least one leg, such gripper foot preferably comprises jaws which can be brought together to effect gripping of a projection from the inclined surface. During construction of a roof it is usual to provide inclined rafters spanned by horizontal purl ins parallel to a ridge of the roof, and a plurality of battens also parallel to ci ridge. By appropriaFe ---r?apinJ and posit oning the gripper foot it can be made possible for the workbench to be mounted on any of these structural elements of a roof construction. Most usually, however, it is anticipated that the workbench would be fixed to horizontal battens since it is considered that the workbench would find its greatest application during cladding of the roof with roofing elements such as slates. It may be used, however, to grip timbers being cut during construction of the underlying roof structure, and it is for this purpose that the gripper foot (or feet, may be adapted to be mounted on any convenient structural element of a roof in order to hold it in position during construction.

The jaws of the gripper foot (or feet) may alternatively by spring-loaded to a closed position to allow rapid-coupling of the foot to a support member on which the workbench is to be carried.

In this case the spring may be positioned on a toggle linkage or other over-centre configuration such that it can be snapped into an open or a closed position by operation of a control lever.

As mentioned above it is preferred that the adjustable legs are telescopic in the sense that each adjustable leg has a component which is slidable adjustably within another leg component and can be fixed in a selected relative position. The adjustable legs may be the longer pair of legs or the shorter pair of legs (it being appreciated that for any inclined surface one pair of the legs must necessarily be longer than the other pair).

The workbench of the present invention may be variously equipped with appropriate holding members and/or working tools for performing the operations necessary during construction of a roof. In particular, it is envisaged that the working platform may removably or otherwise carry a vice by means of which workpieces can be gripped, and that there may further be provided a slate-cutting guillotine, removably attachable to the working platform. There may likewise further be provided a subsidary platform for the operator, lying in a plane generally parallel to that of the working platform. The operator may then stand on the subsidiary platform at a predetermined height in relation to the working platform, and this may either be "uphill" or "downhill" of the working platform with respect to the inclined surface on which the workbench is placed.The subsidiary platform may be articulated to the collapsible frame to allow it to be folded away when not in use. The workbench of the present invention may further be provided with a seat for the operator, again conveniently articulated to the collapsible frame for the comfort and convenience of the operator. This may also be considered as a safety feature in that the seat can be used for the operator to gain a safe rest position when such may be needed.

In detail, the working platform may be provided with two dependent lugs from which the two pairs of legs are pivotally mounted, one leg from each pair being attached to each lug. Such a construction makes it possible for the legs to be collapsible so as to lie substantially parallel to the working platform in the collapsed state. At least one pair of legs is preferably braced by means of diagl braces in order to achieve a strong and rigid structure, although if all fou. lags were provided with trippers for attachment to corresponding parts of a roof structure such braces may possibly be dispensed with.

The legs are preferably positioned nearer one edge of the working platform than the other, again so that the platform can be folded flat against the two pairs of legs which are then themselves folded flat against each other.

Preferably a further support strut extends from a point midway along each shorter leg to a point adjacent the edge of the working platform remote from the said one edge. This strut may, itself, also be adjustable in order to facilitate level adjustments of the working platform, although this strut may alternatively be of fixed length with the level adjustments being made only by adjustment to the length of the adjustable legs.

The said further support struts are preferably pivotally carried on -untc- to the underside of the working platform and releasably connected by an attachment to the said shorter legs.

Embodiments of the present invention may also be provided with a removable tray removably attachable to the legs so as to lie in a position generally parallel to that of the working platform.

Retainer means may be provided for retaining the assembly of legs and working platform in the collapsed position, such retainer means being in the form of, for example resilient clips or other snap-engaging detent means.

According to another aspect of the invention a slate cutting tool, which may be adapted for use with the work bench defined above but which is not exclusively for such use, comprises a pair of parallel, spaced jaws having a separation gap approximately equal to, but slightly larger than, the thickness of a shear-loading member capable of applying a shear force to a sheet-like member placed over the jaws to span the separation gap between them.

Preferably, the shear-loading member is pivoted at one end to the jaws. In this case the shear-loading member may be provided with a handle at the free end remote from the pivoted end.

The jaws may be formed as reinforced edges of a slot in a work piece support frame, and the shear-loading member may be pivoted to the work piece support frame. This latter may be formed as a separate element, removably attachable to the working platform 12 of the workbench, or may, in face, be formed as part of the working platform itself by the appropriate provision of a slot reinforced, perhaps by inlaid steel strips, to make the edges of the slot effective as shear agents.

The present invention also comprehends the combination of a workbench as hereinabove defined with a slate-cutting tool as described above.

One embodiment of the present invention will now be more particularly described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of the embodiment shown in its erected position; Figure 2 is a side view of the embodiment illustrated in Figure 1.; and Figure 3 is a sectional view taken on the line III-III of Figure 2.

eèrriìg now to the drawings çhe workbench shown, generally indicated with the reference numeral 11, comprises a working platform 12 of rectangular form having two parallel longer edges 13, 14 and two parallel shorter edges 15, 16. From the shorter edges 15, 16 depend two parallel lugs 17 at a position along the edges 15, 15 nearer the edge 14 than the edge 13. Pivotally attached to the lugs 17 are two pairs of legs 18, 19 and 20, 21, the legs 18, 19 comprising a longer pair and being pivotally attached to the lugs 17 at pivot points 22 nearer the edge 14 than pict dints 3 by which the legs 20, 21 are attached to the lugs 17.Moreover, the longer legs 18, 19 are pivoted on the inside faces of the lugs 17, that is the faces directed towards the opposite lug, whilst the legs 20, 21 are pivoted on the outside faces of the lugs 17 so that they can both be folded about their pivots 22, 23 to a position substantially parallel to the working platform 12.

The longer legs 18, 19 are telescopically adjustable, and comprise upper outer tBtb lar parts 1 Ra, 19a within which slide inner, telescopically adjustable lower parts 18b, 19b. The telescopic adjustment of each of the legs 18, 19 can be fixed by means of respective clamping screws 25, 26 threadedly engaged in the upper, outer tubular part 18a, 19a respectively and engageable with, for example, a rounded inner end (not shown) against the telescopically adjustable inner leg part 18b, 19b. Alternatively, (although not shown) the lower telescopic leg parts 18b, 19b may be provided with a series of holes at pre-fixed distances from one another, and the clamping screws 25, 26 may be replaced with pins, perhaps springloaded, which can be engaged in selected holes to determine the adjustment of the telescopic legs.In an alternative embodiment (not shown) all four legs may be made telescopic and adjustable so that a wide range of inclinations of the surface can be accommodated.

Each of the legs 18, 19, 20, 21 has a gripper foot at its lower end, and since these are all identical only the gripper foot on the leg 18 will be described in detail. This comprises a generally U-shape bracket 24 having two parallel side arms 27, 28 joined by a base portion 29 from which project two parallel lugs 30 pivotally attached by a pivot 31 to the lower end of the telescopic leg portion 18b. The leg 28 of the U-shape bracket 24 has a screw threaded clamping member 32 with a manually turnable knob by which it can be tightened or released, for example onto a batten 33 as illustrated in Figures 1 and 2. Similar gripper feet on the legs 19, 20, 21 enable the workbench to be securely fixed to a pair of battens 33, 34 to be retained securely in position.In an alternative embodiment (not shown) the gripper feet 24 are provided with the further possibility of swivelling about an axis orthogonal to the pivot axis 31 to enable the gripper feet to be attached to members extending orthogonally of the battens 33, 34, for example roof joists or boat ribs.

The longer, telescopic legs 18, 19 are braced by means of two diagonal braces 35, 36 so that the two legs 18, 19 can turn about the pivot 22 on each lug 17 as a generally planar frame. Likewise, the two shorter legs 20, 21 are spanned by a reinforcing brace 37.

Additional bracing, useful for example when the bench is used on rough or sloping ground rather than on a roof, may be provided in the form of a brace 50, like the strut 38, but spanning the two legs 18, 20. The brace 50 is pivoted to the leg 18 by a pivot 52 on a bracket 51 affording the necessary lateral spacing, and is adjustably clamped to the leg 20 by the clamp 42 passing through a slot 53 in the brace 50 corresponding to the slot 41 in the strut 38.

As mentioned above, the lugs 17 are positioned closer to one long edge '4 of tha working rlatfcrr 1 than the other to facilitate collapsing of the structure. In order to hold the working platform 12 rigidly in its working position, however, it is further provided with two reinforcing struts 38, 39 which are respectively pivoted to depending lugs 40 on the working platform 12, lying parallel to the edges 15, 16 and adjacent to the longer edge 13 opposite the long edge 14 adjacent which the lugs 17 lie.The reinforcing strut 38 has a slot 41 which can be engaged by a screw clamp 42 located at a mid position along the length of the rear leg 20 and a similar cla.ing structure is provided Although such cannot be seen) for the leg 21 and the strut 39. The clamp 42 is made in such a way that it can easily be released to separate the legs 20 and 21 from the struts 38 and 39 to facilitate the folding of the structure upon collapse, and is further adjustable to allow fine adjustment to the inclination of the platform 12 to be made once the clamping feet 24 have been secured to the battens 33, 34 and the major adjustment to the inclination of the platform 12 has been made by varying the length of the telescopic legs 18, 19.

Tn addit on, .he working platform 12 may be provided with a vice 45 and with a slate guillotine 46 useful for cutting or trimming slates to size and/or shape in use. The slate guillotine 46 comprises a workpiece support plane 47 having a slot 48 reinforced with metal strips 49, 50 in this example in the form of angle-iron strips inset into appropriately shaped rebates in the support plane 47 adjacent the slot 48. At one end of the slot 48 are two upstanding supports 61, 62 for a pivot 52 which pivotally connects one end of the bar 51 in alignment with the slot 48. The bar 51 has a handle 60 at its free end and, in this example, is curved (although in other embodiments a straight bar 51 may be used) and acts as a shear-loading member.The right-hand edge of the platform 47 is supported with an underlying reinforcement structure 63 so that the slot 48 is free and unobstructed and can receive the shear-loading member 51. In use, a slate to be cut or trimmed is placed on the platform 47 with the desired line of cut overlying the slot 48 and the handle 50 is then drawn down to shear the slate along the line of the slot 48. By providing support on both sides of the line of cut ensures that the slate is supported and requires no downward pressure by the operator when the relatively high forces for shearing it are applied via the cutting bar 51.

In an alternative embodiment (not shown) the support plane 47 may, in fact, be constituted by the working platform 12.

When collapsed to its folded configuration the workbench 11 occupies very little space and lies in substantially a single plane with the two pairs of legs 18, 19 and 20, 21 lying parallel to one another (the legs 20, 21 lying outwardly of the legs 18, 19 but otherwise in substantially the same plane) and flat against the working platform 12. This makes it easy for the workbench 11 to be carried to and from the work site.

Although described hereinabove specifically for use on roofs, it will be understood that the asymmetric bench of the present invention can be used on any sloping surface, in particular on a staircase. Again, although not described hereinabove, the present invention may also be provided with rollers on the feet 24 in order to facilitate moving the bench along the battens 33, 34, it being understood that these are reasonably accurately parallel and the gripper flanges of the feet themselves would in any case serve to guide the feet along the battens in the manner of rails. In place of the screw clamps 32 a toggle linkage or over-centre mechanism may be employed to enable quick-acting clamping to be achieved, and the operating lever for such mechanism may be specifically adapted to be operated by the user's foot.

Claims

1. A workbench for an inclined surface having a working platform supported on a collapsible frame having two pairs of legs, the legs of at least one pair of which are longer than the others such that the working platform is held substantially horizontally or at a selected inclination when the workbench is placed on an inclined surface.

2. A workbench as claimed in Claim 1, in which the legs of one pair thereof are adjustable in length whereby to adjust the inclination of the working platform with respect to a support surface on which the workbench is positioned.

3. A workbench as claimed in Claim 1 or Claim 2, in which the ends of the legs are provided with engagement means for engaging against ridges or other surface asperities on an inclined surface on which the workbench may be positioned.

4. A workbench as claimed in any of Claims 1 to 3, in which the ends of at least one of the legs has a gripper foot operable to grip a fixed part of an inclined surface whereby to retain the work bench in position on an inclined surface.

5. A workbench as claimed in Claim 4, in which the said gripper foot comprises a clamping member having screw operated clamping means.

5. A workbench as claimed inClaim 4 or claim 5, in which the gripper foot comprises jaws which can be brought together to effect gripping of a projection from the inclined surface.

7. A workbench as claimed in Claim 6, in which the jaws are spring-loaded to a closed position.

8. A workbench as claimed in Claim 7, in which the spring is positioned on a toggle linkage or other over-centre configuration such that it can be snapped into an open or a closed position by operation of a control lever.

A l workbench as claimed n any of Claims 2 to 8, in which the adjustable legs are telescopic.

10. A workbench as claimed in any of Claims 2 to 9, in which the adjustable legs are members of the shorter pair of legs of the support frame.

11. A workbench as claimed in any preceding Claim, in which the working platform is provided with holding means by which a workpiece can be held in a fixed position on the workbench.

12. A workbench as claimed in any preceding Claim, in which the working platform is provided with a slate-cutting guillotine.

13. A workbench as claimed in any preceding Claim, in which the working platform has two dependent lugs on which the two pairs of legs of the support frame are pivotally mounted, one leg from each pair being attached to each lug.

14 A workbench as claimed in any preceding Claim, in which at least one pair of legs of the support frame is braced by means of diagonal braces extending from one leg to the other of the pair.

15. A workbench as claimed in Claim 13 or Claim 14, in which the lugs are positioned nearer one edge of the working platform than the other so that the platform can be folded flat against the two pairs of legs which are themselves foldable flat against each other.

16. A workbench as claimed in Claim 15, in which a further support strut extends from a point mid-way along each shorter leg to a point adjacent the edge of the working platform remote from the said one edge.

17. A workbench as claimed in Claim 16, in which the said further support struts are pivotally carried on mounts to the underside of the working platform and releasably connectable by an attachment to the said shorter legs.

18. A workbench as claimed in any preceding Claim, in which there is provided a container or tray removably attachable to the legs of the support frame in such a way as to lie in a position generally parallel to that of the working platform.

19. A workbench as claimed in any precedingClaim, in which there are provided retainers for retaining the assembly of legs and the working platform in the collapsed position.

20. A workbench as claimed in any of Claims 12 to 19, in which the slate-guillotine comprises a pair of parallel spaced jaws having a separation gap approximately equal to, but slightly larger than the thickness of a shear loading member capable of applying a shear force to a shelf life member placed over the jaws to span the separation gap between them.

21. A workbench as claimed in Claim 20, in which the shearloading member is pivoted at one end to the jaws.

22. A workbench as claimed in Claim 20 or Claim 21, in which the jaws are formed as reinforced edges of a slot in a workpiece support plane and the shear-loading member is pivoted to the workpiece support plane.

23. A workbench for use on sloping or rough ground comprising a working platform having a working surfae, the platform being supported on a collapsible frame having two pairs of legs each pair defining a plane a.ld aii lag being independently length adjustable wheeby to support the working platform at a selected inclination or horizontal when position on any sloping or rough ground.

24. A workbench for an inclined surface having a working platform supported on a collapsible frame having two pairs of legs one pair of which are adjustable to be made longer than the other with the working pltform substantially horizontal when the workbench is placed on an inclined surface, in which there are feet at the lower end of at least one pair of legs incorporating rollers allowing the workbench to be moved in at least one direction by rolling theeon.

25. A workbench as claimed in Claim 24, in which the feet incorporate clamp means for clamping onto upstanding ribs or battens.

26. A workbench as claimed in Claim 24 or Claim 25, in which the feet are provided on all four legs and are inverted generally U-shae members having the roller located in the bight portion tnereof.

27. A workbench as claimed in any preceding Claim, in which at least two of the legs are provided with means for inserting the tip portion thereof onto soft soil.

28. A workbench as claimed in any preceding claim, in which there is further provided a subsidiary platform for the operator lying in a plane generally parallel to that of the working platform.

29. A workbench as claimed in Claim 28, in which the subsidary platform is articulated to the collapsible frame to allow folding away when not in use.

30. A workbench for an inclined surface substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.