GB2317851A - Worktable fence support - Google Patents

Abstract

A worktable includes a rigid frame (2, 3, 4, 5, 6). Tracks (15, 16) are rigidly mounted on the frame and telescopically receive arms (17, 18) supporting a ripping fence (24). The ripping fence is capable of being positioned over a work supporting table (7) or beyond the work supporting table (7), the tracks (15, 16) being open ended so that the arms can be inserted in either end of the tracks 10 position the ripping fence (24) on either side of the saw or other tool supported by the table. Clamping means (23, 24) clamp the arms (17, 18) in the tracks (15, 16). The fence 25 is pivoted to the arms and can hence be reversed to present its sloping face towards the saw.

Description

IMPROVED WORSTABLE FOR SAWS AN9D OTHER TOOlS Field ofthe !nveritiqn This invention relates to improvements in worktables for saws and other tools.

Backgrond of the Invention Most table saws have a calibrated arm affixed to the front, and sometirnes to the rear, of the work support table or to the supporting base below it. The rip fence is substantially elongate, and is clamped by means associated with the calibrated arm. Most saws have a rear clamp to anchor the back of the fencc to the rear of the table, and this is normally applied by the user actuating a lever aftcr having locked the front of the fencc at the desired position for cutting.

The accuracy of this clamping method in terms of achieving a fence setting which is exactly parallel to the saw blade is questionable, and depends on the design, precision of manufacture, and the alignment of the calibrated arm, the clamping means at the front of the fence, and the damp at the rear. Poor design or manufacture, wear and tear, a sharp knock, or even a build-up of sawdust can result in a slightly out-of-parallel fence when the front clamp is tightened. The vicar clamp normally clamps the back of the fence to the table at whatever position is determined by the front clamp. This can lead to potentially unsafe operations, especially if the blade and the fence converge towards the back of the blade.

As well, most table saws suffer from limited rip width capacity because they are not dcsigned to have the rip fence overhang the edges of the work support table. The fence is often clamped directly to the table, as is the caste with the table described in U.S. Patent 402,518 Lenin. This has the limitation that the fence cannot overhang the table, and the maximum rip capacity is therefore limitcd by the width of the table.

Proposals have been made in the patent Iiterature to increase the ripping capacity of a worktable beyond the width of the table, and examples may be found in US patents nos. 2744549 Johnson, 232DQ8o Tautz, 1938548 Tautz and 4174100 Estess. Each of these examples suffers from the disadvantage that they include fixed supporting rails for the rip fence which pennanently extend beyond the edges of the table thereby requiring additional space and creating an undesirable obstruction in the workshop, obstructing movement around the table, and rendering the table much less portable and storable.

Surnmarv of Invention and Object lt is an object of this invention to achieve a range of fence adjustment greater than that provided by the dimensions of the table, without requiring an increase in the size of the table or its base.

Secondary objects which flow from the means of achieving the above primary objcct include the provision of a simple yet reliable means of fitting a reversible rip fence to a table saw to achieve a high degree of accuracy and security in parallel fence setting, and a fence which can be used on the left hand side or the right hand side of the saw or other tool element.

The invention provides a worktable for saws and other tools comprising a work supporting table mounted on a rigid frame, means for supporting the saw or other tool so as to expose a working clement of the saw or tool through the work supporting table, track means rigidly mounted with respect to the work supporting table, said track means having a length not substantially greater than the width of the work supporting table, a ripping fence having ends, arm means attached to the fence at or near the ends of the fence, said arm means being telescopically received in said tracks to enable said ripping fence to be positioncd over the table or remote from the table to thereby increase the ripping capacity of the worktable without any substantial increase in the size of the table.

By attaching the tracks rigidly to the supporting frame, rather than having slots in the work supporting member itself, or having tracks extending beyond the table dimensions, as in the prior art discussed above, the above described outboard location of the fence can be achieved without compromising the design parameters of the worktable. Further, by having arms attached at either ends of the fence, both ends of the fence can be accurately set and hcld according w fixed scales associated with the tracks with the fence being dead parallel provided datum marks associated with the tracks are accurate in their relationship to the working element The track means are preferably open ended and capable of accepting said arm means from either end of the tracks to enable the fence to be prcsentcd on either side of the saw or other tool.

The arms are preferably pivotably attached to the fence to facilitate reversal of the direction of said arms with respect to the fence as well as stowage of the arms when the fence is not in use.

The pivoting of the arms to the fence is preferably locatcd on the longitudinal centre line of the fence, so that when the arms are reversed to present the other side of the fence towards the working element, any datum scales associated with the arms will still read accurately in relation to any datum marks on the tracks.

One of the arm pivots preferably has a small amount of guided longitudinal movement in the working direction of the fence. This allows the pivot to UfloatH so that fence adjustments are easy. Instead of having to always move the fence parallel to the blade, the front and the rear of the fence can be independently set and there is no tendency for the fence arms to jam up in the tracks.

The fence preferably has opposed high and low perpendicular guide faces, to accommodate a tilted saw blade, the low face being presented rovvard the working element by reversing the direction of the anns about the pivots.

The fence preferably has one perpendicular face and also has a 459 bevel face which can be used to support workpieces for bevel ripping and chamfering. A low perpendicular guide face is preferably provided at the lower edge of the bevel face.

The hypotenuse face is preferably provided with tracks which receive workpiece supports for supporting the lower edge of the workpiece above the table during bevel ripping and chamfering operations. These supports are preferably Iongitudinally positionable to provide maximum support to workpieces in front of and behind the working element and behind any overhead guard support for the working element.

The arms and the tracks are calibrated and datum referenced to accurately locate each arm with respect to the working element and clamping means are associated with each arm and track to securely clamp each arm in its track when its position with respect to the working eIernent has been achieved. The calibrations preferably include two sets of calibration scales and two sets of datum marks at cach end of the worktable to enable accurate extension of the arms and the fence from a first ripping range predominantly inboard of the table, to a second ripping range predominantly outboard of the table.

The clamping means preferably comprises one or more clamping bolts at each end of the worktable, the hcads of which are slidably captive inside the arm, preferably in association with a clamping strip. A cam-type mechanism is associated with each clamping bolt whcrcby the clamping bolt forces the arm down against a face which has a profile which co-operates with a profile on the underside of the arm, to achieve greater contact area and accurate guidancc.

The profile preferably comprises v-grooves on the base of the calibrated arms and co-operating offset v-grooves in the clamping tracks to achieve a guided and rigid locking arrangement which allows the fence to overhang the edge of the worktable, despite only being damped by the outer ends of the arms. This greatly increases the rip capacity, without significantly diminishing the ri-idity of the fence.

If desired, the fence has at least one internal track running parallel to the vertical working face which can be used for mounting of adjustable sub-fences, workstops, captive push-sticks or pressure wheels, as well as providing a handy stowage position for the overhead guard and support.

The above definitions apply to the currently preferred embodiment of the invention, which is a multirurpose worktable for a saw. In the case of a dedicated saw bench in which conversion from table saw mode to cross-cut mode is not required, it is not essential for the tracks to be secured to the frame means. They could rather be fitted to the ends of the table, thereby providing an even greater adjustment range through the use of lengthened arms.

Bnef Description of lhe l:)rawinga In order that the invention may be more readily understood, a presently preferred embodiment of the invention will now be described with reference to the accompanying drawings in which: Figure 1 is a perspective view from one end of a worktable embodying the present invention showing the various parts assembled; Figure 2 is a plan view of the worktable of Figure 1; Figure 3 is an exploded view showing the mechanism for locking of the fence arms in the tracks at the ends of the table of Figures 1 and 2; Figure 4 is a schematic exploded view of the floating pivot means for attaching at least one of the arms to the fence; Figure 5A and 5B are schematic views of the table showing the means by which the extended rip capacity is achieved without permanently increasing the size of the table; Figure SC is a similar schematic view of the table showing the manner in which the rip and bevel fence is able to be reversed; Figure 6 is a perspective view of the rip and bevel fence; Figures 7A to 7C are schematic end views of the fence showing the bevel guides attached thereto and illustrating the different modes of operation, and Figures 8 and 9 illustrate the means by which guidance of the protractor strip is achieved in the protractor slot track Description of Preferred Embodiment Referring firstly to Figure 1. of the drawings, the worktable embodying the invention comprises a front end panel 1, and a rear end panel 2 connected by horizontal channel members 3 and 4 and spaced bearing channel 5, and an overlying table 7 having a central saw slot 8 and spaced parallel protractor guide tracks 9 and 10. Legs 11, 12, 13 and 14 are pivotally attached to supporting flanges on the front and rear end panels 11 2, and these legs support the table at an appropriate elevated position and are foldable for storage and transport.

The front and rear end panels 1 and 2 each have a track 15, 16 rigidly mounted thereon by means of bolts (not shown) so that the tracks 15, 16 are rigidly fixed with respect to the supporting frame structure comprising the end panels 1 and 2, the base channels 3 and 4 and the bearing channels 5 and 6 and each track has a flange 15', 16' (Figure 3) which supports the edges of the table 7. Each track has two spaced datum marks 1513 and may have further datum marks applied by the user if desired.

As shown in greater detail in Figure 3 of the drawings, each track 15, 16 is defined by an open-ended channel member having inwardly directed narrow lips 15A, 16A, with each channel member telescopically receiving a rip-fence supporting arm 17, 1S formed with ribs 17A. 18A which engage under the lips 15A, 16A to hold the arms 17, 18 captive within the tracks 15, 16 with the upper face of each arm 17, 18 exposed as shown. Each ann 17, 18 is formed with inwardly directed base flanges l7BX 18B defining a central slot 17C, 18C, and the lower surfaces of the flanges 1X, 18B are formed with v-shaped locating ribs 17D, 7SD. The base of each track 15, 16 is formed with upstanding v-shaped ribs 15B, 16B defining grooves 15C, 16C extending the length of each track 15, 36 and with which the ribs 17I 18D mate to ensure proper location of the arms 17, 18 and smooth guidance within the tracks 15, 16.

The arms 17, 18 are provided with pars of offset calibration scales 19, which are visible through tops of the tracks 15, 16, and which enable the arms to be accurately set to the alternative rip capacity settings of 0 to 320mm and 320 to 620mm, using the datum marks 15C on the tracks 15, 16, or an alternative datum mark 15D (Fig. SA) near the other end of the tracks 15, 16.

Each track 15, 16 houses a pair of elongate clamping strips 20, 21 which engage the upper surfaces of the flanged clements 1713, 18E3 and are held in place by one or more bolts 22 which pass through the central slot 17C, 18C to engage cam lever locking mcchanisms 23, (Figure 3) each of which include a top cam plate 23A, having a lower cam surface 23B, a cam lever B C, carrying a nylon cam insert 23D and a cam rctainer plate 23E, each of which has a central hole receiving the bolt 22 which in turn is engaged by a lock nut 22A to hold the locking mechanisms 23 in housing cavities 23F in each of the front and rear end panels 1 and 2. By rotating the cam lever in the appropriate direction, the clamping strips 20, 21 are drawn by the bolt 22 to engage the flanges 17B, 18B of the arms 17, 18 to securely locl; the arms 17 13 at any selected position within the tracks IS, 16. The arms 17, 18 can be released by reversing the movement of the cam lever 2313 of the clamping mechanism 23 when desired.

Each arm 17, 18 supports one end of a rip and bevel fence 24 having a perpendicular workpiece guiding face 25 and a 45" hypotenuse or bevel face 26 formed with parallel guide receiving tracks 27, 28 (Figure 6), with the lowcr track 28 adaptcd to receive bevel guides 29 positioned to support a lower edge of the workpicce for bevel ripping, as shown in Figure 6 of the drawings. The fence 24 has a low perpendicular guiding face 26A at the lover edge of the bevel face 26. The arms 17, 18 are sccured to the fence 24 by pivotal connections located on the longitudinal centre lines of the arms and of the fence 24. One of the pivots is provided with a small amount of guided longitudinal movement itt the working direction of the fence, as illustrated schematically in Figure 4. This arrangement allows the pivot to "noat" so that fence adjustments are easy In this way, instead of having to always move the fence parallel to the blade, the front and the rear of the fence can be independently set and there is no tendency for the fence arms to jam up in its tracks, provided the difference between the front and rear fence settings is less than about 300mum. The pivotal attachment of the arms 17, 18 to the fence 24 allows the direction of the arms to be reversed, as schematically illustrated in Figures 5B and 5C of the drawings, to present the bevel face 26, and the low perpendicular face 26A, of the fence 24 towards the saw blade S.

Referring to Figures 5 and SA of the drawings, the alternative modes of positioning the rip and bevel fence are illustrated. In the first illustration of Figure 5, the fence 24 is position.ed to the left of the saw blade S and the arms 17, 18 engage the tracks and project from the right of the table to provide from G to 320mm rip capacity using the right hand datum mark 1zB on the front panel 1. m the second illustration of Figure 5A, the arms 17, 18 extend laterally from the side of the worktable and the fence 24 is rigidly and securely supported by the arms at a position remote from the table 7, as clearly illustrated, and the rip capacity of The table is extended from 320 to 620mm using the second datum 15B associated with the tracks 15, 16 or the left hand side of the front panel l. It will bc appreciated that if desired the fence 24 can be positioned, in either of its modes, on the other side of the saw blade S.

Each af the tracks 8, 9 and 10 in the table 7 have the shape and crosssectional configuration as shown in Figure 8 of the drawings, and the tracks can support a protractor strip having thc configuration illustrated in Figure 9 of the drawings. Each track (Figure 8) has pairs of spaced downwardly extending guiding lips 30, 31, one or the other of which engages a slot 32 in the protractor strip of Figure 9, to guide the protractor strip in the manner illustrated schematicaIiy in Figure 7 of the drawings. The advantage of the extrusion profile illustrated in Figure 8 is that each of the guiding lips 30, 31 presents a stable dimension when formed as an aluminium extrusion and can therefore be used to accurately guide the protractor relative to the position of the saw blade S as determined by its fitting to the table 7. The downward direction of the guiding lip reduces sawdust fouling of this guidance mechanism.

It will be appreciated that the central track 8, which is slotted to receive the saw blade S, may support an overhead guard G of the type illustrated in Figure 1, and the power driven saw is fitted underneath the table 7 after attachmcnt to a saw slide chassis C, illustrated schematically in Figure 1 of the drawings, which engages the bearing channels 5,6. The overhead guard & is clamped in position within the central track 8 by means of a simple locking mechanism IL which spreads a avo- picce metal element to firmly engage the sides of the track 8 when the locking element L is pushed down to the locked position.

The table can be converted from the illustrated ripping mode to a cross cut mode, in a manner similar to that shown in U.S. Patent 4,502,518, by removing the overhead guard assembly G and moving aside or removing the rip fence 24, removing the table 7 adjusting the height of the table support rails 33 (Figure 2) on the front and rear panels 1 and 2 by means of the flange nuts 34 to suit the saw size in question, slide the table 7 in frorn the side until the central slot is directly below the blade and secure the table by pushing the table latches fully home into the cutauts jn the table support rails A cross-cut fence (not shown) is thcn fitted to the table 7 by means of T-shaped holes 7a, 7b, 7c and 7d, (Figure 1) to provide the necessary guidance for cross-cut operation. When the fence 24 is removed, the arms 17, 18 are pivoted inwardly and the fence 24 is stowed using the angle supports A illustrated in Figure 1 of the drawings.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination. of the steps of any method or process so disclosed.

Claims (17)

THE CLAIMS DEFIN1NG T INVENTION ARE AS FOLLOWS:

1. A worktable for saws and other tools comprising a work supporting table mounted on a rigid frame. means for supporting the saw or other tool so as to expose a working element of the saw or tool through the work supporting table, track means rigidly attached to the frame, said track means having a length not substantially greater than the width of tht work supporting table, a ripping fence having ends, ann means attached to the fence at or near the ends of the fence, said arms being tetescopically received in said tracks to enable said ripping fence to be positioned over the table or remote from the table to thereby increase the ripping capacity of the worktable without any substantial increase in the size of the table.

2. The workable of claim 1, wherein said track means are open ended to accept said arm means from either end to enable the fence to be presented on either side of the working element, said track means being slotted at the top to expose an upper face of said arm means within said track means.

3. The worktable of claim 1 or 2, wherein said arm means are pivotally attached to the fence to enable reversal of the direction of the arms with respect to the fence.

4, The worktable of claim 3, wherein the pivotal attachment of one of the arm means has a small amount of guided longitudinal movernent in the working direction of the fence to allow the pivot to float so that movement of the arm means in the track means is relatively free.

5. The worktable of claim 3 or 4, wherein the pivot attachment of the arm means to the fence coincides with the longitudinal centre line of the fence such that when the arm means are reversed any datum marks or scales on the arm means will still read accurately in relation to any datum marks on the track means.

6. The worktable of any preceding claim, wherein said fence has opposed high and low perpendicular guide faces.

7. The worktable of any one of claims 1 to 5, wherein said fence has one perpendicular face and a 45" hypotenuse ar bevel face which can be used to support work pieces for bevel ripping and chamfering.

S. The workable of claim 7, wherein said fence has opposed high and low perpendicular guide faces, said bevel face extending from said low perpendicular guide face.

9. The worktable af any preceding claim, wherein said arm means and said track means have calibration marks and datum reference marks to accurately locate each arm means with respect to the working element

10. The worktable of claim 8, wherein the calibration marks on said arm means include t'vo sets of calibration scales and the datum marks on said track means include two sets of datum marks at each end of the worktable to enable accurate extension of the arms and the fence from a first ripping range inboard of the table to a second ripping range outboarcl of the table.

11. The worktable of any preceding claim further including clamping means associated with each arm means and track means to securely clamp each arm means in its track means when the desired position with respect to the working element has been reached.

12. The worktable of claim 10, wherein the clamping means includes one or more clamping bolts at each end of the worktable, the bolts having heads of which are slideably captive inside each arm means in engagement with a clamping strip, a cam mechanism associated with each clamping bolt and arranged to force the arm means down against a guide face of said track means to hold the arm means in position within the track means.

13. The worlitable of any preceding claim, wherein each track means has a bottom face which is profiled to cooperate with a similar profile on an underside of each ann means to achieve greater contact area and accurate guidance berween the track means and the arrn means.

14. The worktable of claim 13, wherein each arm means has v-grooves on its underside and the track means have co-operating offset v-grooves to produce a guided and rigid locking arrangement which allows the fence to ovcrhang the edge of the worktable despite only being clamped by the outer ends of the arms.

15. The worktable of any preceding claim, wherein said work supporting table includes at least one guide track for receiving a protractor aftachment, including a guide slot defined by at Icast one downwardly extending guiding lip adapted to engage a similarly dimensioned groove in a protractor strip.

16. The worktable of claim 16, wherein the slot is defined by a pair of downwardly extending guiding lips each capable of engaging the slot in the protractor strip.

17. A worktable for saws and other tools constructed and arranged substantially as herein described, with reference to the accompanying drawings.