GB2523582A

GB2523582A - Saw-action carpentry plane

Info

Publication number: GB2523582A
Application number: GB1403554.7A
Authority: GB
Inventors: John Edmund Poynton
Original assignee: Individual
Current assignee: Individual
Priority date: 2014-02-28
Filing date: 2014-02-28
Publication date: 2015-09-02
Also published as: GB201403554D0

Abstract

A plane has a substantially flat base (1, figure 1) and a rotatable circular saw blade 4 set into the base, wherein the blade is arranged to be substantially coplanar with the base. The plane preferably comprises an electrically powered motor (5, figure 5) for driving the blade. A cradle may be provided to support the blade within the plane and to allow the position of the blade relative to the plane to be adjusted. Preferably the tilt of the blade and the lateral position of the blade relative to a side edge of the plane may be adjusted. The plane may comprise two or more counter-rotating blades.

Description

Patent Specification

Title: Saw-action Carpentry Plane

Description:

The idea for this plane came about a couple of years ago when I was building some decking at the rear of our house. I had not done any carpentry work for some time, and so dug out my old Stanley plane I had purchased in the late 1950s. It just got bunged up in no time, so I perused the internet to see if electric planes had been invented. They had, so I went down to our local DIV shop to have a look at one. There were models available from a variety of manufacturers, and I saw that they all used the same roller-blade function. So I bought one.

It was not a success. Not only is it heavy and cumbersome to use, but it also has a habit of taking a great chunk out of the wood as it falls over' the end.

For many of the pieces I wanted to plane, some of them at odd angles on fairly small pieces, I ended up using the side of the circular saw on my work bench. This worked brilliantly as the hardened teeth on the saw are quite wide and have right-angled sides to them as well. I was able to get a perfectly smooth finish as well as finesse shapes to fit as required very easily.

I have therefore invented an alternative plane that uses a circular saw blade set into a metal base that can be otherwise similar to that of a classic Stanley plane. This is defined in the attached claims.

A plane according to the invention is shown in the figures by way of example, as follows:- Drawing No.1 shows a side view of the plane; the following key applies:- 1. Metal base plate * 2. Lateral adjustmentscrew 3. Toggle On/Off switch securing button 4. Hard plastic handle S...

* 5. Electric cable * . . * " 6. Circular saw with square-profiled hardened teeth 7. Retractable front safety stand with contacts on top 8. Forward guiding handle 9. Side grip 10. Vertical adjustment wheel 11. Tilt adjustment wheel 12. Trigger switch.

Drawing No.2 shows the base plate profile; the following key applies:- 1. Base plate bottom 2. Handle assembly fits in between flanges, and is secured by countersunk screws in base.

Drawing No.3 shows the plane from beneath; the following key applies:-1. Front 2. Curled up 3. Retractable safety stand in slot 4. Saw, shown at maximum lateral adjustment to the left, protruding by about 1mm from the side.

5. Handle assembly countersunk fixing screws.

Drawing No.4 shows the motor and saw assembly; the following key applies:- 1. Motor housing 2. Armature flange 3. Saw 4. Fixing screws 5. Screwed rod for vertical adjustment, fixed over armature housing 4** 6. Collar with side screw hole for tilt adjustment (rotated 900 for illustration) 7. Holes or sheaths for cradle. e. *. * . * * *

Drawing No.5 shows a vertical section through the centre of the plane; the following key applies:-**** * **** * 1.Saw 2. Armature flange 3. Base plate fore and aft of saw 4. Base plate inner flanges 5. Motor is reversible for left-handed use -details of armature and screwed rod fixings not shown but latter screws on around former.

6. Lateral and securing screws 7. Clutch plates 8. Motor housing 9. Part of handle assembly in location 10. Screwed rod for vertical adjustment.

Drawing No.6 shows the cradle for the motor/saw assembly; the following key applies:- 1. Four rods slot through holes/sheaths in motor housing. Circular plates at each end pack up against housing to ensure no lateral play.

2. Rods can screw into one end plate, but will require circlip or similar fixing at the other once the motor is on. Circular rubber pads may be necessary (fitting inside the circlip) glued on both sides of the plates.

3. Outer surfaces of end-plates are rough so that they can act as a clutch against similar plates attached to screw adjusters in the plane base plate sides. This provides for tilt adjustment before tightening to hold motor assembly firmly in use. The screw adjusters used in tandem also provide lateral adjustment of the saw position relative to the plane sides.

Drawing No.7 shows the inside view of the baseplate with the saw fully retracted; the following key applies:- 1. Motor cradle end plate OS. * n C aW

3. Flange indent to take handle moulding 4. U-shaped indent to take cradle inserted from the top.

Drawing No.8 shows the retractable safety bar and contacts; the following key applies:-S...

S

". : Safety Bar 2. Contacts 3. Coil springs are fitted around both retraction cable ends between the safety bar and the top of its recess in the housing to hold weight of the plane when off (not shown) 4. Retraction cable to trigger switch in rear part of handle housing 5. Electric cable from rear 6. Electric cable to motor 7. Front section of plastic housing 8. Collar to keep retraction cable above hooks 9. Metal bar which retraction cable pulls around 10. Metal Base Plate 11. Housing moulding also guides safety bar fore and aft (not shown).

Drawing No.9 shows the inside view of one side of the rear handle mounting; the following key applies:- 1. Push button toggle securing/release switch (mechanism not shown) 2. Metal pole to reverse switch cable direction 3. Conduit to one side for electrIc cables 4. Trigger switch shown fully depressed and secured 5. Rear view at this section showing ventilation for motor 6. Collar 7. Top of motor housing with contacts 8. Knurled wheels for vertical and tilt adjustment -note elongated retainer slots for each to allow for the other's movement 9. Holes in front casing to one side as conduits for cables. Note switch cable must be centred by metal poles in the front section. Space must also be left for tension to be adjusted after assembly. This can be done by swinging the tilt wheel out on its collar to reach the :r male/female adjustor behind. en...

* The layout can be seen in Drawing No.1, which shows the side view. The plane consists of the metal base, with a curled-up front like a ski (but unlike the classic plane) to place the plane onto the work more accurately. The centre is raised to hold the mechanism and then falls away again towards the rear. Small flanges on either side provide a locator for the upper handle *2. assembly and countersunk screws through the base secure the upper assembly to it. Drawing No.2 provides a rear view of these flanges in the

S

base plate. There is a gap half way along the base on either side to allow the saw blade to protrude slightly. This enables a clean right-angled cut to be achieved when required. The upper assembly does not protrude beyond the metal sides at any point so that it does not foul the work in such situations.

The plane can be made in a variety of sizes to suit varying needs from builders to model makers. I envisage that the full-sized plane will use mains electricity, whilst smaller models will require external adaptors. Because the smaller planes will use smaller saws with finer teeth, the power required will be correspondingly lower.

The cable enters the handle at the rear below a lip in the handle moulding, which is made out of a hard plastic as two sides bolted together, which enables the heel of the hand to maintain a downwards pressure to keep the plane on the work right to the end of the planing stroke. The wires are threaded through conduit holes inside the handle to the front safety-bar assembly. This is a plastic bar that protrudes through the base of the plane just in front of the saw's leading edge to keep the blade clear of any surface when it is switched off or is running down after being switched off.

The safety bar is held out by a spring, reasonably stiff as it has to hold the weight of the plane plus any inadvertent pressure added on top, at the centre, but is retracted by a cable link to the trigger switch in the handle.

This cable is lopped around the trigger switch so that each end is attached to one end of the safety bar, and has a male/female length adjustment on one side (inside the handle, which would have to be detached for this adjustment). The contacts are situated on the top of the bar so that the plane only starts when the bar is fully retracted. The trigger switch has a toggle button to enable it to be fixed in the "on" position so that the plane * can then be guided either by a light two-handed action, the sawing action requiring very little effort, or one handed so the tool can be used tofinesse edges, ends and convex curves while the other hand holds the work. The handle moulding has flat or recessed sides at the centre to enable a secure one-handed grip on top forward of the handle. The plane can be held up by *:*. the front handle when operating the toggle switch.

It is envisaged that the saw will rotate in a clockwise direction as seen from above. This will ensure that for a right-handed worker viewing the cutting line from the side will have the sawdust ejected away from him. Left-handed planes can be produced by inverting the motor and saw blade.

Drawing No.3 shows the underside of the plane, with a circular recess in the base plate to accommodate the saw. The position of the saw in the base plate is adjustable in three dimensions by screw adjustors, thereby giving very precise settings, which enables the tool to be used also for fine skimming and paint removal. To enable this the motor and saw assembly is housed in a cradle which is held by the base plate but attached to the handle assembly via screw adjustors. The amount of adjustment in each case is quite small. The vertical adjustment allows the blade to travel between full retraction and the width of a tooth. The lateral movement enables a protrusion of up to 1mm on either side, the saw diameter being the same as the width of the base. The third dimension is a forwards tilt so that the front edge of the saw protrudes whilst the rear is retracted, to avoid inadvertent cuts when moving the plane around. The recess in the base plate must allow for the tilt and lateral movements but otherwise fit closely to avoid misalignment with the work surface.

Drawing No.4 shows the motor and saw assembly. The saw is attached directly onto the armature flange by countersunk screws. It is necessary to detach the saw from this flange to disassemble the plane since the saw will not fit through the base plate flanges just above, as shown in Drawing No.5. The motor housing has four sleeves the width of the motor, one at each corner (or alternatively eight eye-holes set at the cubic corners of the housing), so that it can be held firmly by the cradle) shown in Drawing No. , which consists of two discs connected by four rods which thread through the sleeve holes in the motor housing. The outer surfaces of the discs are rough.

The cradle sits in the base plate flanges described above which protrude inwards above the saw blade. Drawing No. 7 shows the U-shaped indent in these flanges at an inside view, into which the cradle discs slide from the top. When the handle moulding is secured to the base plate the cradle cannot move vertically more that required for adjustment, the moulding having a semi-circular matching profile over the cradle discs which also slides down into the U-shaped recesses in the base plate flanges. The cradle can thus rotate slightly to produce the tilt) and be raised to withdraw the saw into the plane. The cradle discs can also slide laterally a couple of millimetres within the flanges so that the saw can protrude from the side of the base plate by up to 1mm on either side as described above.

The lateral movement of the cradle is adjusted by screwing and unscrewing two flush screws, one either side of the plane set into the raised part of the base plate. These screws have a wide diameter, and on the inner end of each a further disc is fitted and secured by a small countersunk screw into the axis of the wide screw. The outer surface of this disc is also rough. Thus as the two side screws are tightened at the desired lateral position of the saw, the discs pairs act as a clutch to hold the cradle tightly in position.

Vertical and tilt adjustments can only be made whilst the lateral screws are loosened. These are then made using knurled wheels set into the handle moulding so that they cannot move axially. A fixed screwed rod is attached to the top of the motor housing, in line with the armature, and threads through the top wheel thus providing the vertical adjustment. A collar on this rod, below the wheel, has a thread just to one side so that a second screwed rod at right-angles to it can thread through it and the front knurled wheel, where it is fixed, providing the tilt adjustment. Alternatively the tilt rod can be fixed at the collar end and left loose in the wheel. Each of the screwed rods can move laterally in slots in the handle moulding either side of their wheels to provide for adjustment in the other.

The handle moulding is made in three with a single front section containing the retractable safety bar and electric contacts, and the top and rear made in two halves. The front guiding handle could also be integral with the front 0***e * section. Drawing No.8 shows a cross-section of the safety bar and contacts mechanism. The cable comprises three sections, like the brake mechanism on a bicycle, so that both sides of the bar lift evenly. The rear part of the cable comprises two parts joined by the male/female tension *.r adjustor, which also enables the parts to be assembled separately.

Drawing No. 9 shows one half of the rear section, in which the retraction cable loops around another metal bar to create the pull effect when the trigger is squeezed, the size of the trigger extension inside the handle matching in length the travel required in the safety bar. This part contains locators for all the mechanisms inside the handle, as well as the various cables, so that the second part can be bolted on to complete the assembly.

C *. .. * . . * *

S S... * S

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Claims

Claims: 1. A plane having a generally flat base, and a rotatable circular saw blade set into the base, the blade being arranged substantially coplanar with the base.
2. A plane according to claim 1 in which the blade is driven.
3. A plane according to claim 2 further comprising an electrically powered motor which drives the blade.
4. A plane according to any one of the preceding claims, further comprising a cradle supporting the blade within the plane, thereby to allow the position of the blade relative to the remainder of the plane to be adjusted.
S. A plane according to claim 4 as dependent on claim 3 in which the cradle also supports the motor.
6. A plane according to claim 4 or claim 5 in which the cradle allows the depth of cut to be adjusted.
7. A plane according to any one of claims 4 to 6 in which the cradle allows the tilt of the blade to be adjusted.
8. A plane according to any one of claims 4 to 7 in which the cradle allows the lateral position of the blade relative to a side edge of the plane to be adjusted.
9. A plane according to any one of the preceding claims further comprising a safety bar set into the base of the plane which retracts when the plane is in use but which protrudes below the base of the plane to hold the cutting edge of the blade clear of the surface when not powered.
10. A plane according to any one of the preceding claims which comprises two or more counter-rotating blades to limit the torque snatch when the plane is started or in use.Amendments to the cbims have been made as follows Claims: 1. A plane having a generally flat base, and a rotatable circular saw blade set into the base, the blade being arranged substantially coplanar with the base, and having hardened teeth such as those with tungsten carbide tips and which have a right-angled profile standing proud of the blade body so that the side of each tooth is coplanar with the base, so as to provide a smooth finish to the work surface It is the nature and profile of the teeth that makes this invention unique.2. A plane according to claim 1. in which the blade is driven.3. A plane according to claim 2 further comprising an electrically powered to motor which drives the blade.4. A plane according to any one of the preceding claims, further comprising a cradle supporting the blade within the plane, thereby to 0 allow the position of the blade relative to the remainder of the plane to be adjusted.O 5. A plane according to claim 4 as dependent on claim 3 in which the cradle also supports the motor.6. A plane according to claim 4 or claim 5 in which the cradle allows the depth of cut to be adjusted.7. A plane according to any one of claims 4 to S in which the cradle allows the tilt of the blade to be adjusted.8. A plane according to any one of claims 4 to 7 in which the cradle allows the lateral position of the blade relative to a side edge of the plane to be adjusted.9. A plane according to any one of the preceding claims further comprising a safety bar set into the base of the plane which retracts when the plane is in use but which protrudes below the base of the plane to hold the cutting edge of the blade clear of the surface when not powered.10. A plane according to any one of the preceding claims which comprises two or more counter-rotating blades to limit the torque snatch when the plane is started or in use. IC) a)