GB2393675A - Drilling apparatus - Google Patents

Abstract

A portable power drill A1 comprises a housing for a drill chuck A6 and a motor, which is slidably mounted on two or more supports A5. The supports are carried on a base plate B1 provided with an aperture B2, and the housing is movable toward or away from the baseplate in line with a drill bit held in the chuck. The axis of the drill passes through the aperture, and locating means are provided which are associated with the other face of the baseplate for positioning a workpiece relative to the aperture. The supports are arranged to enable a mark on the workpiece to be visually aligned in the aperture when desired.

Description

( DRILLING APPARATUS

Background

If a craftsman were to cut a length of wood of square section, say 2"x2" in half, set out and drill a 1/2" hole 1" deep into the centre of one end of each piece of wood, and then rejoin them using a piece of 1/2" dowel, he would be unlikely to be able to revolve one piece in relation to the other In 90 degree increments and expect the edges to align smoothly. Maybe once in twenty attempts.

The invention of this power tool (hereafter referred to as the Device) was suggested by a wish to circumvent the limitations that are placed on the speed, accuracy and scope of my woodworking by my inability to drill holes that are accurately located and perpendicularly bored with conventional power drills.

I shall explain how the Device might solve some of the problems that craftsmen face firstly by describing the difficulties and Implications of two (of many possible) such situations, then by allusion to such solutions,and their hmitations, as are currently available, and lastly by a description of my

invention and some of the ways in which it might be used.

A carpenter hanging windows and doors on site today has to insert all kinds of security, weather and I fireproofing devices mto holes, slots and mortices of one shape or another. Since he cannot, for example, easily drill a 20mm hole perpendicularly 70mm into the end-grain at the top of a door stile, he drills it oversize and relies for a secure fixing of the lock on the screws attaching the face-plate. He might claim that this did not matter since the results look the same - what he wants to do is hang as many doors in a day as he can. However he also spends much rime actually setting out the holes that he is going to drill. Only when that is done can he attempt to locate the tip of the bit on the pomt he has marked and then bore the hole as perpendicularly as he Is able. If the drill he was using not only guaranteed a perpendicular hole but located itself on the correct spot for drilling then would be working faster, more accurately, and with less glitches to subsequently resolve by compensating elsewhere for his Inaccuracy. He would furthermore be able to drill similar holes in other doors with no setting out required at all.

Owing to both necessity and choice furnture-makers are increasingly making use of man-made sheet materials In an environment ever more preoccupied with savings In labour and transportation costs.

One result of this has been a proliferahon of clever items of hardware that enable the production of furniture (whether tradhonal in appearance or not) the "modern" way, which might further imply assembly by the enduser Great accuracy might be required to effect this successfully many sheet materials are faced with melamine or some such and therefore may not be trimmed, moreover if the items are for user-assembly then the parts must be constructed with joints that align correctly in the first place, rather than by being pre-assembled m the workshop, taken apart. packed as an independent entity, and re-assembled by the user (this example from my own experience). Perusal of a comprehensive furniture- fittings catalogue will reveal an enormous variety of items which have to be inserted precisely in the faces, edges, and ends of workpieces, many of which can only be used effectively by those with large, sophsucated and very expensive computensed borers Setting out and drilling holes accurately in the edges of cupboard (let alone multiple matching rows) is extremely difficult with a hand-held tool A visit to a good tool shop will turn up a number of devices that address, or attempt to address, some of these and other similar problems: There are available cheap stands that do hold the users own drills fairly vertically. They may only be located manually on flat surfaces equal to or exceeding the dimensions of their base-plates, their downward travel is Inaccurate (partly as a consequence of the handle of the conventional drill not

(:;L being in line with the drill bit) they cannot in any circumstances be used on edges or ends their depth stops are ineffective and their baseplates were not designed for use with templates (which would have represented the only means of accurate location had this not been so).

It is possible to buy guide-bushes from specialist suppliers These are available in limited sizes for limited types of drill bit must be built into Jigs and are not an option wilhngly adopted Bushes are generally used in the manufacture of specialized jigs supplied at considerable cost for the insertion of specific items of hardware (user-assembly "knock- down" fittings in particular). Neither these nor dowelltng jigs (extinct apparently) can be used for anything other than their specific function Pillar drills are intended for metal-workers and have almost no application in woodwork.

Electric routers are versatile tools for which vast ranges of accessories are available. They are capable of drilling beautifully crisp holes but with limitations on their use as drilling devices too serious for them to constitute an effective solution to problems relating to holes: I) They are intended for use as moving tools - not for the static operation Implied by the word "hole".

2) They can only be used vertically on top of the workpiece - not horizontally.

3) They have a limited vertical travel (to my knowledge no router cutter longer than 50mm is available) 4) They require the use of router cutters (rather than ones normal drill bits) which are expensive break easily if thin and used to their full depth and which are very aggressive if the tool should be wobbled while working at depth This latter possibility is exacerbated by the point of rotation of the wobble being the base-plate of the tool - not the cuttmg edge of the much gentler drill bit. Furthermore router cutters have no leading point for guiding the main body of the cutter. Not only does this prevent them trying to guide themselves straight but it makes it difficult to locate the tool immediately above a proposed hole.

5) The latter problem is compounded by the sprung supports of the tool being in-line with the cutter.

This means that when drilling holes using the fence under the base-plate (the usual means of guiding or steadying the machine) one cannot align the bit with any lines marked perpendicular to the edge against which the fence is rested.

6) They are designed for two-handed operation. Unless used with templates (for the static use of which their base-plates are often not well designed) they can only be used with the hand that Is applying the downward pressure far from the ofI/on switch since pressure must be applied centrally and ones other hand is securing the base-plate.

7) They have fences but no lateral stop and therefore no means of fixing a static location other than by the use of a jig or template A well-known woodworking book advises craftsmen to adapt a pillar-drill to work horizontally in order to drill accurately into edges and ends Aside from the problems encountered by woodworkers attempting the metalwork involved in this the resulting contraption would be extremely cumbersome and tmeconsuming to use effectively Apart from these suggestions we are left with either the acquisition of a huge CNC borer or with setting out and drilling manually I now suggest an alternative: General description of my invention

In accordance with my Inventor a drill assembly has an apertured base plate. On one face of the base plate two or more supports such as pillars perpendicular to the plate are arranged and these carry slidably mounted thereon a housing for a drilling unit for example consisting of a motor with a drill chuck mounted on its shaft either directly or via appropriate gearing. The housing can be moved towards or away from the aperture on the supports on which it can slide and the direction of movement

( is precisely aligned with the axis of a drill bit held In the drill chuck and perpendicular to the face of the base plate opposite the face to which the supports are attached The arrangement is such that, by pushing the housing to make a drill bit held in the chuck pass through the aperture, it does so precisely in the direction of its own axis and perpendicular to the surface of a workpiece, such as a piece of wood, which Is abutted against the underside of the base plate.

By arranging the supports so that they do not lie, e.g.diametrically opposite the aperture, it is possible to align a workpece relative to the aperture so that the drill will penetrate a precisely desired point.

The location of the workpiece is ensured by providing locating means which are mounted on the base plate and which serve to locate a workpiece in the desired position.

Such an arrangement is much better than the devices known up till now and it enables an accurately perpendicular hole to be drilled in a workpiece surface. By using suitable short stops or long stops which are attachable to the base plate In appropriate positions, a very wide variety of shapes and sizes or workpiece may be easily accomodated and precisely located.

The housing and base plate may have some form of interactive adjustable stop means so that the housing cannot be asdvanced towards the base plate more than a certain limit This means that the drill cannot project from the aperture in the base plate note than a certain amount, i.e it acts as a depth gauge for the hole that Is being drilled.

Further details of how this invention can be put into practice are evident from the accompanying drawings which show some examples of how the invention may be applied.

Introduction to the drawings

Drw. I Fig. 1: General view of basic device, inactive, without additional means of location.

Drw 2 Fig.2: General view of device active Depressed, and located by template (depth/height stops not included) Drw.3 Fig 3 Plan view of baseplate with all means of location attached.

Drw.4 Fig.4: General view of baseplate with 2 fences set for work on edges (transverse guidance) Fig 5 General view of baseplate with 2 fences set for work on faces ( ") Fig 6. Side view of Figure I Fig 7. Side view of Figure 2 Fig.8: Front view of Figure I Drw 5 Fig.9: General view of baseplate with one of 2 short-stops extended (lateral location) Figl O. Side view of short stops In both stored and active positions Fig I I. Front view of range of short stops In normal position Fig. 12 Front view of range of short stops in inverted position Drw.6 Fig. 13: General view of baseplate with 2 long stops and a collar fitted (lateral location) Fig 14 Detail of long stop and collar mounted on bar Fig. 15 Side view of long stop Fig 16 Front view of long stop.

All general views depict the same aspect of the front and left side of the device.

Identical features in a symmetrical arrangement are usually only numbered in one instance.

All part numbers are preceded by a letter. This refers to the feature or function described on a particular page of drawings, and is intended to simplify comprehension.

The word "guidance" means that the device is retained with mobon along one axis possible, and "location" that no mobon is possible.

Drawing I Figure I

( At Here the motor contained in casing (Al) Is inactive and pushed upwards by the four sprung supports (A5) to the maximum extent of its perpendicular travel. The motor may be electric (powered or cordless) or driven by compressed air. The electric version would have a speed control (not shown). In this mode ( without additional means of guidance or location fitted) the device may be used freehand, merely to achieve perpendicular holes, or held against a straughtedge affixed to the workpece for guidance. All functions of the device may be used with equal facility by left or right handed persons. One hand secures the baseplate (B I) while the other controls the on/off switch (A2) and applies downward pressure Should the user wish to increase his pressure (perhaps he is using a blunt drill bit) he may spread his fingers over the switch and press on the top of the casing. This is an unusual type of switch for a power tool - should there be an objection on the grounds of safety, a more standard fitting might be adopted. The chuck (drill bit holder) is as supplied with conventional power drills and deploys the same bits.

The depth stop (A3) controls the extent of downward travel. The height limiter (A4) controls the extent to which the drill ascends. The latter firstly facilitates setting up by freeing the users hands from the need to retain the tip of the drill bit near the work surface against the pressure of the springs, and secondly saves labour when using short bits. No further reference will be made to either of these two features as they are standard on many power tools (B I) is the baseplate by which all the separate functions of the device are brought together. The l aperture (B2) through which the drill bit passes is centrally located. It is shown in all figures of all drawings (except 6/14) and is not denoted again. Lmes (B6) are marked vertically across all four edges l of the baseplate as well as on the same axes in the aperture (B2) and are to assist location of the device. It will be seen that parts prefaced by (A) are features of the motor casing and those by (B) of the baseplate. Parts prefaced by (C) (D) or (E) are to be associated with, in this order, the fence(s), the short stop system and the long stop system. These will be explauned shortly.

Drawing 2 Figure 2 Here the device is pictured active, depressed and located on the workplace by a template - which might prove the best means of boring multiple holes on faces, particularly where repetition Is Involved.

A square punch that when laid on a thm sheet material and struck will cut through (or at any rate cut) the positions of the corners corresponding to those of the baseplate might be usefully supplied with the device to assist in the manufacture of templates Drawing 3 Figure 3 This is a plan view of the baseplate (B 1). The three principal means of guidance or location are all represented In basic form here, and will be expanded upon in the three following drawings (4-6). This drawing might most usefully be examined in conjunction with the latter as it serves as a plan view In all cases (B3) and (B4) represent the areas occupied by the depth stop and height limiter assemblies respectively. (B5) are holes through the baseplate that are countersunk on the top surface and which allow the user to attach the device to Jigs in unusual circumstances.

Drawing 4

( The primary means of guiding the device on faces and the only means on edges and ends is by means of one or two fences (C2a/b/c in their various forms). In most cases two fences are used in preference to one simply for assured accuracy however if either side of the baseplate has been positioned on a face against a straightedge (as suggested m Drawing I paragraph 1) then these fences might be used to afford lateral location for drilhng either one or two points It must be noted that the bars (C3) that unite the fence(s) with the baseplate (and which are of the same section as that used for the long stop (E) assembly) should be supphed in different lengths for convenience of use Without very long bars large workplaces might preclude the use of two fences The collars (E2) that will be described In Drawmg 6 might also be used to enable removal and precise relocation of the two bars with one fence attached.

Figure 4 The device is here set to be laterally guided on an edge in a fixed transverse position. Positive location might additionally be obtained by the use of long or short stops (D or E) the use of which will be explained shortly.

The fences (C2) are in their "b" form - produced either by screwing flanges to the basic C2 mounting or preferably for user convenience supplied as a pair in this form It should be noted that the ends of the fences which project beyond the sides of the baseplate do so only as far as effective use of the maximum extension of the short stops (D) will permit. The user pmches these projecting ends onto the workpiece with thumb and middle finger - the index resting on the top surface of the baseplate. Thus may a firm location be obtained.

Parts (C I) are the lugs through which the fence bars (C3) pass bemg retained by bolts (here depicted in "butterfly" form) Figure 5 Here the fences(C2) are being used to achieve similar ends on the face of a panel. The fence pictured on the right Is in its "a" form which will extend beneath the baseplate and is most convenient for use on the faces of smaller panels The "c" form on the left (which is the "a" form reversed on the bars) is best for larger panels since it makes fuller use of the span of the bars (C3) as well as sitting on the edge of the panel - thus obviating any tendency for long bars to sag when used at their greater extensions Both C2a and c permit work to be carried out on thin panels lymg flat on a surface The dotted sem'-circle on the right-hand fence shows the fomm to be taken by an additional type of fence (supplied singly) which will allow drilling across an edge provided a suitable (Forstner or similar) bit be used.

Figure 6 is a side view of figure 4 Figure 7 is a side view of Figure 5.

Figure 8 Is a front view of Figure 4.

Drawing 5 This Illustrates the short stop system (D). Like the long stop (E) this can only be used as an adjunct to the (C) fence(s). It is to secure lateral location on edges or ends that have a length less than that of the fence(s) (C2b). There are two stops (D I) - one to each side of the drill aperture and running from left to right in a groove that traverses the underside of the baseplate. Each has three possible basic positions: inactive/stored and active with either maximum or minimum extension Unlike functions (C) and (E) which are commonly found on woodworking equipment feature (D) is to my knowledge

G unique to this device Figure 9 is a general view of the baseplate with short stop (D 1) in its active position of maximum extension. Figure 10 A side view of the stop both active and stored that is with the locating stub(D3) housed In a hole(D2) near the edge of the underside of the baseplate. The stop is secured In this and other positions by the tightening of screw (D5). Despite the advantages of extending the range of these stops by extending the adjushnent slots (D6) in the baseplate I consider it best to house the stubs (D3) In a separate hole -

in the event of the screw (D5) becoming loose while the device is in use with other means of guidance the stop will not be permitted to drift towards the revolving drill bit. The screw should have a milled edge so that it may be adjusted to finger-hghtness but must also have a deep slot so that it may be secured firmly with a screwdriver. The stop has three threaded holes that allow it to be fixed by the screw in a variety of positrons.

Figure 11 A front view of the range of travel of the stop in its "normal" position of maximum extension Figure 12 A front view of the range of travel of the stop in its Inverted position. This is for use on very small ends - indeed the small projection of the drilled bar of the stop that extends a short way behind the stub will allow the device to operate on ends of smaller dimensions than the drill aperture(B2). To drill the for the dowel as suggested in the opening paragraph of this description one would use

functions (C) and (D) - and a number of pieces of wood of the same section for the process of trial and error necessary to set up the device sufficiently accurately for t}us purpose.

Drawing 6 This illustrates the long stop system (E) - the usual means of fixing lateral location. The required number of stops (E I) and if required collar (E2) are secured onto the bar (E3) by means of bolts (E6).

This assembly Is then inserted at least halfway through the hole (E4) that passes through the baseplate so that it may be secured by bolt (E5).

For the greatest versatility of use the stops (E I) should be constructed so that they might revolve around the bar (E3) while maintaining their position along its length.Should this not be feasible then two forms of stop should be supplied: one through which the bar (E3) may pass and one through which it will not. The latter is to be positioned at an end of the bar and may be removed from and restored to the same position Collar (E2) determines the position of the bar carrying the stops relative to the baseplate - into which it may be inserted from either side thus preserving the distance between the drill bit and the stops. It may be noted that a stop might equally fulfill the function of a collar.

Figure 13 is a general view of the assembly as described above.

Figure 14 shows a stop (E I) and a collar (E2) mounted on a bar (E3) Figure 15 is a side view of this feature Figure 16 Is a front view of the bar (E3) passing through the hole in the baseplate (E4) and secured by bolt (E5).

To conclude I shall briefly return to the example posited in paragraph 5 of this Descriphon: A furniture-maker wishing to manufacture a userassembly wardrobe is using drilled cam finings to

( connect, say, the top panel to the side panels. A minimum of two cams along each joint will be required. First he clamps the top panel vertically m a woodworker's vice so that one end is uppermost. He places the Device on the end with the two fences (C2b) straddling the workpiece as illustrated in Drawing 4 Figures 4 and 6. He adjusts the traverse position of the drill bit (perhaps first making use of a test-

piece to this end) and tightens all relevant bolts when satisfied.

He now has available various options for the setting of the stops in order to secure the lateral location of these two holes He may fit one long stop on either side of the Device equidistant to the baseplate (and to the drill bit) so that he might bore one hole with one stop engaging the front edge of the panel and then, moving the Device, bore the second hole with the second stop engaging the rear edge. If he has not set the stops equidistant from the baseplate he will have to set up again to bore the opposite end of the panel.

If, however, he were to mount two stops and a collar on a bar extending only to one side of the Device (as pictured in Drawing 6 Figure 13) he could bore the first hole with one stop engaging the front edge and then the second with the other stop also engaging the same edge. He may therefore move the bar with the stops and collar attached to the other side of the Device when boring identical holes into the other end of the same panel. In this instance any variation In the width of the panel would be Immaterial since he is always locating from the same (front) edge.

He retains the position of the stops and collar on the bar when he comes to bore the matching holes in the sides of the wardrobe, although he will have to remove one of the fences from the device since he will now be working on the face of the panel.

Claims (1)

1. g ( CLAIMS

   I) A drill assembly comprising a baseplate with an aperture, one face of the baseplate carrying two or more supports, a housing for a motor and a drill chuck slidably mounted on the supports such that the housmg may be moved toward or away from the baseplate in line with a drill held in the chuck, the axis of the drill passing through the aperture and, associated with the other face of the baseplate locating means for positioning a workpece relative to the aperture, and wherein the supports are arranged to enable a mark on the workspace to be visually ahgned In the aperture where desired 2) A drill assembly according to claim 1, wherein the assembly has an adjustable depth gauge to limit the distance the housing may be moved towards the aperture 3) A drill assembly according to claim 1 or claim 2, wherein the locating means include at least one groove in the other face of the baseplate in which a short stop member may slide, and an attachment means for securing the short stop member in a fixed position 4) A drill assembly according to claim 3, wherein the short stop member has a plurality of threaded holes. 5) A drill assembly according to claim 4, wherein the attachment means comprises an adjustment slot on the one face of the baseplate communicating with a groove on the other face of the baseplate, and a screw which can fit through the slot and engage a threaded hole in the short stop member to secure it in position against the baseplate.

   6) A drill assembly substantially as hereinbefore described with reference to the accompanying drawings.