This invention relates to planes for use in woodworking. Background Art

Woodworking planes of various types are well known. For example, the conventional hand-held plane comprises a body having a sole plate with an opening therein, and a cutter blade adjustably mounted on the body with its cutting edge projecting through the opening in the sole plate. Forward movement of the plane results in the blade cutting and smoothing the surface of the work piece. Electric planes are also known, which similarly comprise a body having a sole plate comprising an infeed table and an outfeed table with an opening therebetween. A rotary cutter driven by an electric motor has a cutting section projecting through the opening. The plane is still moved to and fro by hand, but the drive to the cutter is from the motor rather than relying on manual effort. The infeed table may be adjusted to alter the depth of cut.

Both the hand-held and the electric plane are effective and efficient tools in smoothing the surface of a work piece. However, there is also a requirement for thicknessing planes- that is to say tools capable of uniformly cutting an elongated work piece to a required thickness, either across the whole surface of the work piece or in a predetermined band of the work piece. The only effective types of thicknessing plane currently in use are large and expensive power-driven pieces of equipment dedicated to that particular function. It would be of advantage if the conventional small hand or electric plane was able to perform a thicknessing operation, and the invention seeks to provide a plane which will perform such function. Disclosure Of Invention

According to the invention a plane comprises a body having a sole plate, a cutter mounted on the body and projecting through an opening in the sole plate, and two skids mounted on the body and spaced apart transversely of the sole plate, each skid having a support surface lying in a plane parallel to the plane of the sole plate.

A plane in accordance with the invention may thus be used to thickness a work piece so that the finished work piece has a thickness equal to the perpendicular distance between the plane of the cutting part of the blade and the plane of the skids. If the skids are co-planar then the work piece will be finished in a plane parallel to the plane of a support on which the skids rest; if the skids are not co-planar then the work piece may be finished to a plane lying at an angle to the plane of such support.Thus, the plane according to the invention may be produced to give any desired result.

Preferably each skid is adjustable relative to the sole plate in order to adjust the perpendicular distance between the plane of the sole plate and the plane of the support surface of the respective skid. By calibrating the adjustment of the skids, thicknessing to required dimensions may readily be achieved.

In one embodiment of the invention the skids may be mounted at opposite sides of the body, whereas in an alternative embodiment the skids may be mounted apart at the same side of the body, being cantilevered out from the body. The first embodiment readily allows thicknessing of a work piece lying between the skids, whereas the second embodiment allows thicknessing of a work piece lying to that side of one skid which is opposite to the side on which the other skid lies. In this latter embodiment thicknessing or rebating of a section only of a work piece may be effected. Conveniently each skid is mounted on the body by way

of a parallelogram guide system that ensures that in all positions of adjustment the plane of the skid is parallel to the plane of the sole plate. A simple method of mounting each skid is to mount it on a support bar secured 5 to the body, and if a parallelogram guide system is used that may then extend between the support bar and the skid. Adjustment may then simply be effected by an adjusting screw operating between the support bar and the skid. Such screw may be calibrated, preferably with direct calibration

10 to indicate work piece thickness, and may suitably be of the micrometer type threaded in the support bar and having an enlarged head that is rotatable relative to, and captive in, a groove formed in the upper surface of the skid.

Alternatively, each end of each skid is connected to

15 be axially captive on one end of a threaded bolt supported for axial movement relative to the body, and a nut is in threaded engagement with the bolt and is supported for rotation relative to the bolt and the body but to be axially fixed relative to the body. In this case, each

20 skid may have an associated support bar secured to the body, each bolt passing through a bore in the support bar, and each nut being axially captive on the support bar.

In either embodiment, each support bar may be directly secured to the body of the plane, or may be secured to one

25 or more rods or other guides extending from the body. In the latter case the rods or guides may be adjustable so that skids may be fitted thereto either to lie one to each side of the body or both to lie to the same side of the body.

30 Brief Description Of Drawings

Figure 1 is a side elevation of a hand plane according to the invention;

Figure 2 is a front elevation of the plane of Figure

1; 35 Figure 3 is an enlarged view of part of the plane of

Figure 1, with parts thereof in different positions;

Figure 4 is a section on the line IV-IV of Figure 3; Figure 5 is a side elevation of part of a second embodiment of hand plane; Figure 6 is a plan view corresponding to Figure 5; Figure 7 is a side elevation of an electric plane according to the invention;

Figure 8 is a plan of the plane of Figure 7; and Figures 9 and 10 show alternative ways in which the plane of Figures 7 and 8 may be employed. Modes For Carrying Out The Invention

Referring now to Figures 1 to 3 these show a hand plane having a body 1 with a sole plate 2 and forward and rear handles 3 and 4. A blade 5 is mounted on the plane and projects through an opening (not shown) in the sole plate in conventional manner. The blade 5 may be secured relative to the body in any manner suitable for a hand plane, for example by an adjusting screw 6. At each side of the body of the plane a support bar 7 is secured by screws to the body, and each support bar has associated therewith a skid 8. Two angled guides 9 and 10 which lie parallel to one another have internal slots which engage pins 11 and 12 on the support bar and pins 13 and 14 on the skid. The pins, guides, support bars and skids form a parallelogram linkage. The lower surface of the support bar and the upper and lower surface of the skids each lie parallel to the plane of the sole plate 2, and the parallelogram linkage thus constrains each skid to move so that its lower surface always retains its parallel relationship to the sole plate. The perpendicular distance between the support bar and the skid, and thus the perpendicular distance between the lower surface of the skid and the lower surface of the sole plate may be adjusted by a micrometer screw 15 extending through a

correspondingly threaded bore 15a in the support bar. The lower end of the screw has an enlarged head 16 which is captive in a groove 17 formed in the upper surface of the skid 8. Rotation of the screw will thus move the skid upwardly or downwardly relative to the support bar and thus to the sole plate, the skid being always retained in its parallel relationship to the sole plate. An enlarged section 18 at one end of the groove 17 allows assembly of the parts. The screw 15 is suitably calibrated on a scale that represents the distance between the sole plate and the lower surface of the skid.

The assembly of the skids at the two sides of the plane is identical. Accordingly, it will readily be seen that if the two skids are set at identical settings they may run on a plane surface 19 and will support the sole plate parallel to that surface and at a predetermined distance above that surface. If a work piece is now supported and held in position on that surface between the skids the plane may be operated so that the blade will cut material from the exposed surface of the work piece and will eventually smooth and thickness the work piece so that it has a substantially uniform thickness equal to the perpendicular distance between the plane of the sole plate and the plane of the lower surfaces of the skids. For example. Figure 2 shows a perpendicular distance d_ between the planes of the sole plate and the skids, and a workpiece may thus be planed to have a uniform thickness d_. A very accurate result may be obtained.

If the skids are adjusted to different distances from the sole plate it will then be seen that the blade will lie at an angle to the support surface, and a work piece may then be finished to a required angle and thickness.

Figures 5 and 6 show an alternative form of skid assembly that may be secured on each side of a hand plane, in a manner similar to that illustrated in Figure 1. Each

skid assembly includes a support bar 20 secured to the respective side of the plane by screws such as 21. Below the support bar there is a skid 22 having a planar lower surface 23 that will be arranged to be parallel to the plane of the lower surface 24 of the sole plate of the plane. The support bar has bores 25, 26 at its forward and rearward ends, through which pass threaded bolts 27, 28 respectively. The lower end of each bolt terminates in a thrust plate 29, 30 respectively, beyond which reduced diameter extensions of the bolt extend downwardly through bores in the skid 22. Each extension terminates in an enlarged head 31, 32 respectively and the skid is held axially captive on the bolt by circlips 33, 34 engaging grooves on the extensions of the bolts. Each bolt has an associated nut 35, 36 having a groove into which extend fingers 37, 38 of keeper plates 39, 40 secured by screws to the support bar. The keeper plates hold the respective screws axially relative to the support bar, while allowing the screws to rotate relative to the support bar. The upper ends of the bolts are covered by protective plastics caps 41, 42. Each of the screws 35, 36 has a calibrated upper surface 43, 44 as seen in Figure 6, ^• and pointer-elements 45, 46 are secured by screws to respective ends of the support bar 20. It will be seen that the skids may be adjusted relative to the support bars, and thus relative to the sole plate by rotation of the nuts 35, 36, such rotation causing axial movement of the bolts 27, 28 and thus movement of the skids. Using the calibrated surfaces of the nuts in conjunction with the pointers it is a simple matter to achieve any required adjustment of the skids, and to ensure that the lower surfaces of the skids are parallel to the lower surface of the sole plate. Thus, the plane may be used in the manner already described with reference to the plane of Figure 1.

Figures 7 and 8 illustrate an electric plane having similarities to the hand plane shown in Figure 1, but with the blade replaced by a rotatable cutter 50 driven by a suitable electric motor supplied with power by a cable 51. The cutter 50 is mounted for rotation on the plane body 52 and forward and rearward handles 53 and 54 are provided in known manner. The rotary cutter projects below an infeed table 55 to the level of an outfeed table 56, the two tables together forming a sole plate. In this embodiment the plane body has two transversely extending bores such as 57 through which pass respective rods 58 and 59, the rods projecting to each side of the body. At each end, each of the rods is secured to a support bar, 60 and 61 respectively. The connection between the rods and support bar may be a releasable and adjustable connection so that the support bars may be adjusted in their lateral position relative to the body of the plane, or the connection may be a fixed connection. Each support bar has an associated skid 62, 63 respectively connected to the support bar by a parallelogram linkage incorporating guides such as 64, 65 similar to the guides 9, 10 shown in Figure 1. Each skid may thus be adjusted relative to its respective support bar, while maintaining a parallel relationship between the lower surface of the skid and the sole plate of the plane. An adjusting screw 66, preferably a calibrated micrometer screw is provided between the support bar and the respective skid for effecting this adjustment.

It will be apparent that an electric plane could equally well be fitted with skid arrangements such as those shown in Figures 5 and 6, rather than with parallelogram linkage skids.

Figure 9 shows one way in which the plane of Figures 7 and 8 may be used to thickness a work piece 67 located between the skids 62 and 63. The skids rest on a support surface 68 which also supports the work piece and use of

the plane until the skids both run flat on the surface of the support surface 68 will cause the cutter 50 to cut the work piece to a preset thickness equal to the perpendicular spacing between the plane of the cutting part of the blade and the plane of the lower surfaces of the skids.

Figure 10 shows an alternative use, with the rods 58 and 59 or adjusted to lie principally to one side of the body 52 of the plane, with both skids 61 and 62 lying to the same side of the plane. The plane may thus work along one edge only of the work piece 66 supported on the surface 67 in order to rebate a section of the work piece to a thickness equal to the perpendicular distance between the sole plate and the plane of the lower surfaces of the skids. The skids on the planes shown in the Figures have rounded leading edges in order that they may clear the stop that is conventionally provided for the work piece to rest against. It will be appreciated, however, that this is not essential. It will also be understood that many modifications may be made to the planes shown in the drawings, and that the methods of skid mounting described are only examples of many methods that may be used. For example, the lower surfaces of the skids may project downwardly beneath the sole plate and the skids may be connected to the body by simple screws which may be released and tightened at will. Setting to a desired thickness may then readily be achieved by inserting a uniform thickness shim between the skid and the sole plate and securing the skid to the body with the shim firmly clamped in position, if calibrated adjusting means on the plane body are required, then these may be provided in ways other than the simple micrometer screw described. It will further be understood that the invention may be applied to any type of hand plane or small electric plane and those shown are merely illustrative.

Industrial Applicability

The invention provides planes which may be used for accurately planing a workpiece to a predetermined thickness. Furthermore, an existing plane may be modified by securing skid assemblies such as those shown to the body of the plane, and it is contemplated that kits for the self-assembly of the skids may be provided. It is also possible to modify an existing plane by mounting it securely in a cradle that is provided with skids similar to those described herein, those skids being adjustable relative to the cradle body by a parallelogram linkage or by any other suitable adjustment system.