Device for precise angle guidance of a handsaw

Abstract

Device for guiding a saw blade (41) of a hand saw (40) during sawing with a workpiece support and means for guiding the saw blade in a predetermined position relative to a workpiece edge of a workpiece (20), characterized in that • that the workpiece support is formed from a profile (1) extending in the longitudinal direction of the workpiece with at least one horizontally and one vertically oriented contact surface for the workpiece (20), • the profile (1) has one or more slots (2) in the profile wall(s) for inserting the saw blade (41) during sawing, • the saw blade (41) is guided by a support body (10) having a system (12) for the saw blade (41) which can be aligned relative to at least one side of the profile (1) and can be adjusted in height and / or fixed, • the support body (10) with the support (12) for the saw blade (41) and at least one support surface of the profile (1) for the workpiece (20) together define at least one horizontal and / or one vertical saw angle (15 / 16), which is fixed or adjustable, • magnetically acting means (11) integrated with the support body (10) are provided, which exert an adhesive force on the saw blade (41) guided along the system (12) during sawing, • the support body (10) has a cut such as a bevel or a fold (17) running in the sawing direction and facing the saw blade (41) and the workpiece (20), wherein the fold (17) can be formed in particular by a sliding surface (12) fastened to the support body (10) on the saw blade side.

Description

[0001] The present invention lies in the technical field of sawing devices, in particular those used for processing wood.

[0002] When sawing, there is usually a desire to maintain defined cutting angles. For example, to cut a rod-shaped workpiece at a right angle using a handsaw, it is necessary for the saw blade to be guided at a right angle to the workpiece both horizontally and vertically throughout the entire cut. While appropriately trained people, such as qualified carpenters, can achieve a sufficiently high level of angular accuracy for typical carpentry work without aids, this is difficult for inexperienced users. For this reason, so-called miter boxes are commonly available on the market. These usually have settings for horizontal angles of 90° and 45°, while the vertical angle is usually 90°. The problem with these solutions, however, is that the saw blade is usually only guided horizontally and vertically.the vertical and horizontal cutting angles are not guided without play, which results in correspondingly inaccurate absolute cutting angles and also does not allow for acceptable repeatability. To make matters worse, these miter boxes, particularly those made of wood, are subject to considerable wear, i.e. the work results deteriorate with increasing use. This is essentially because the saw blade is guided over the entire cutting height and the interlocking saw teeth inevitably wear down the guide surfaces. The publication DE000008236932U1 describes a miter box with replaceable sliding surfaces for the saw blade which are nevertheless subject to wear from the interlocking saw teeth.

[0003] A further disadvantage is that these miter boxes must either be held by hand on a work surface or clamped to it so that the movement of the device caused by the sawing motion does not result in further inaccuracies.

[0004] The document DE 12 56 397 A describes a handsaw guide that is pivotably mounted on a column for sawing at any angle.

[0005] The document EP 0 015 731 A1 describes a hand saw guide that is placed on a workpiece.

[0006] The document DE 295 03 580 U1 describes a miter box for cutting profiles with a holding device for the profile to be cut.

[0007] The document JP H11- 58 306 A also describes a guide device for a saw to be placed on the workpiece.

[0008] The document DE 203 05 242 U1 describes a device for the simultaneous sawing of two workpieces at 45° angles, in particular for the construction of frames.

[0009] The document US 2010 / 0 224 046 A1 also describes a guide device for a saw to be placed on the workpiece.

[0010] The publication DE 20 2007 016 558 U1 describes a bevel with adjustable legs for adjusting the saw angle, e.g. of a miter saw.

[0011] None of the above-mentioned documents discloses the combination of features in claim 1 of the submitted application.

[0012] The present invention is therefore based on the object of providing a device which allows high absolute and reproducible accuracies when sawing preferably rod-shaped workpieces and is ideally subject to no or only minimal wear during use and enables easy handling.

[0013] The object is achieved according to the invention in the form of a first solution by a device having the features listed in claim 1, ie by a: Device for guiding a saw blade (41) of a hand saw (40) during sawing with a workpiece support and means for guiding the saw blade in a predetermined position relative to a workpiece edge of a workpiece (20), characterized in that • that the workpiece support is formed from a profile (1) extending in the longitudinal direction of the workpiece with at least one horizontally and one vertically oriented contact surface for the workpiece (20), • the profile (1) has one or more slots (2) in the profile wall(s) for inserting the saw blade (41) during sawing, • the saw blade (41) is guided by a support body (10) having a system (12) for the saw blade (41) which can be aligned relative to at least one side of the profile (1) and can be adjusted in height and / or fixed, • the support body (10) with the support (12) for the saw blade (41) and at least one support surface of the profile (1) for the workpiece (20) together define at least one horizontal and / or one vertical saw angle (15 / 16), which is fixed or adjustable, • magnetically acting means (11) integrated with the support body (10) are provided, which exert an adhesive force on the saw blade (41) guided along the system (12) during sawing, • the support body (10) has a cut such as a bevel or a fold (17) running in the sawing direction and facing the saw blade (41) and the workpiece (20), wherein the fold (17) can be formed in particular by a sliding surface (12) fastened to the support body (10) on the saw blade side.

[0014] Further embodiments emerge from the dependent claims and from the following description.

[0015] The essential inventive ideas underlying the first solution are: • The saw blade is guided by a magnetic holding force along a support surface, which in turn is precisely aligned to a workpiece edge or two long sides of the workpiece. This prevents or greatly minimizes angular errors for the horizontal and vertical saw angle. • The support body with the contact surface for the saw blade is placed on top of the workpiece. In combination with a recess for the saw blade, e.g., in the form of a rebate, which is dimensioned according to the height and interlacing of the saw teeth and which can also be realized with a replaceable sliding layer applied to the support body, damage to the saw blade guide by the saw teeth is prevented. • By turning the support body, it is possible to observe the saw blade on both sides while sawing. • The saw bed can be easily attached to the now widely used workbenches and multi-function tables or tool transport cases with perforated panels; this means that no additional clamping is required. For this purpose, it is particularly intended that bolts are attached to the underside of the workpiece support which have a diameter corresponding to the holes in the worktop (usually 20mm or ¾ inch) or are slightly smaller, so that a fit with little or no play is achieved. The interchangeability of the bolts is advantageous here, so that worktops / perforated panels or workbenches with different hole diameters can be used. It is sensible to design the bolts so that they have a continuous internal thread so that they can be attached from the top side of the profile base, in particular with countersunk screws, and if necessary also with knurled screws, for example, from the underside of the worktop.This is particularly useful for use with tool cases with a hole pattern on the lid, as it prevents the device from accidentally coming loose when opening the lid or transporting the tool case. It is also planned to mount at least one of the bolts so that it can be moved longitudinally along the profile, allowing for adaptability to different hole spacings on the worktop / hole pattern panel.

[0016] Overall, the guide for the saw blade is structurally separate from the guide for the workpiece, which is not the case with a conventional miter box, for example, where the side slots in the usually square U-profile both specify the cutting angle and guide the saw blade at the same time. This means that both parts can be optimized for their specific task. An L-profile could also be used as a profile; this would place fewer restrictions on the width of the workpiece. An upright V-profile is also conceivable for special applications. A material that is low-wear and has low friction values, such as polyoxymethylene, is suitable for the saw blade guide, while an absolutely wear-free and rigid material, such as metal, makes sense for the workpiece guide.

[0017] A further embodiment of the invention provides that it is also possible to fix the workpiece in or on the workpiece support or the support body; this can benefit the accuracy of the saw cut and also simplify handling, e.g. if the device is not fixed to a base but has to be held by the operator. In particular, it is provided that one of the slots in the profile wall of the workpiece support that is not used for the saw blade or for fastening the support body can be used to accommodate a suitable clamping device, such as a knurled screw with a pressure body that presses against the workpiece and a holder for the knurled screw, which is height-adjustable in the slot and transfers the pressure forces to the profile wall.

[0018] In principle, the device is designed for horizontal sawing angles of 45° and 90°, with a vertical sawing angle of 90°. These can be easily achieved with a triangular support body (see example). Additional angles can be achieved using different, interchangeable support bodies and / or with additional contact bodies that complement a first support body. Magnetically attaching the additional contact bodies to the first support body is an advantageous solution.

[0019] A further advantageous embodiment results from the use of an at least partially transparent support body which enables simultaneous observation of the saw teeth of the saw blade and the desired cutting line which may be marked on the workpiece, in particular when aligning the saw blade relative to the workpiece before sawing, also on the side facing the support body.

[0020] It is also intended that the support body can be used with a workpiece stop that is placed on the workpiece instead of the channel-like workpiece support (e.g. a U-profile) into which the workpiece is placed. In particular, it is advisable to provide the support body with an L-profile that is fastened to the side with which the support body otherwise rests on the profile wall. The fastening can also be carried out using the eccentric clamp and the profile projects upwards or downwards over the support body. The support body can be placed on a workpiece with this contact surface formed from the profile, resting on the workpiece with its top or bottom, depending on whether the L-profile is mounted with the open end pointing upwards or downwards.Alternatively, a plate can be attached to the support body, especially so that it extends beyond both the top and bottom of the support body, so that the workpiece stop does not have to be repositioned when the support body is turned. Accordingly, the workpiece stop, together with the shape of the support body, defines the horizontal sawing angle, while the vertical sawing angle is determined by the angle of the contact surfaces for the saw blade relative to the bottom and top of the support body.

[0021] As an alternative to mounting the fixture in holes in worktops or other suitable surfaces with bores, it is also conceivable to mount an additional profile, for example with an L-shaped cross-section, on the underside of the workpiece support, which would allow the fixture to be easily clamped in vices or workbench clamps. The same holes in the profile base could be used as for attaching the bolts, allowing the bolts to be exchanged for the additional profile depending on the desired clamping situation.

[0022] For reasons of dimensional stability, it makes sense to manufacture the profile from a metallic material, particularly aluminum. To protect the saw teeth after cutting through the workpiece, it is proposed to insert a replaceable strip of wood-based material into the profile and then place the workpiece on top. This has the additional advantage that the underside of the workpiece is less frayed by the sawblade when cutting through it than with a conventional miter box, where the base of the profile is permanently recessed after some use and offers no support for the workpiece at the saw cut point. This sacrificial layer can be easily replaced as it wears out by moving further along the profile or by turning it over and, of course, replacing it.

[0023] In summary, the main advantage of the invention is that it enables very precise saw cuts with repeatably high absolute angular accuracies and that the construction is not subject to the usual wear and tear.

[0024] An embodiment of the invention is described below with reference to Fig. 1-6 explained. Fig. 1 shows a top view of a (here U-shaped) profile 1 with elongated holes 3 and a bore 4 in the profile base (each for countersunk screws), as well as fastening slots 5 and slots for the saw blade 2 in the profile walls. The profile rests on a worktop 30 with bores 31. Fig. Figure 2 shows a sectional view of profile 1 with countersunk hole 4 in the profile base and a bolt with an internal thread 6 attached to the underside of the profile via countersunk hole 4—the fastening screw is not shown here. Furthermore, the worktop 30 with a hole 31 is also shown in a sectional view. Fig. 3 shows a plan view of a triangular support body 10 with magnets 11 embedded in two side walls forming the contact surfaces for the saw blade and overlying sliding layers 12 as well as a threaded bore 13 in which an eccentric clamp 14 is mounted as well as a first saw angle 15 and a second saw angle 16. Fig. 4 shows a sectional view of profile 1, which is inserted or fastened with bolt 6 in bore 31 of worktop 30, furthermore a workpiece 20 lying in profile 1, and the support body 10 fastened to a profile wall with eccentric clamp 14 through one of the fastening slots 5. Furthermore, two magnets 11 fastened in support body 10 are shown, which in turn are covered by sliding layer 12 (the magnets in the second contact surface, which are behind them from this perspective, are not shown here). Sliding layer 12 is flatter than support body 10 and fastened centrally to support body 10, resulting in a bottom and a top bevel 17. Fig. 5 shows in plan view the profile 1 with the inserted workpiece 20, the support body 10 fastened to the lower profile wall with the eccentric clamp 14 and a saw blade 41 of a saw 40 resting on a support of the support body 10, wherein the saw blade 41 is guided through two of the slots 2 located opposite one another in the profile walls and the profile rests on the worktop 30 or is fastened therein (the fastening with the bolts is not shown here - see Fig. 4). Fig. 6 shows a sectional view of the support body 10 with the magnets 11 and the sliding layer 12 as well as an L-shaped profile 18 which is fastened to the support body 10 with the eccentric clamp 14, wherein the underside of the support body 10 together with the part of the L-shaped profile 18 projecting downwards beyond the support body forms a support or workpiece stop for the workpiece 20.

[0025] The device can be operated as follows: First, at least two bolts 9 are loosely attached to the underside of profile 1 using countersunk screws. The distance between the bolts is adjusted using one of the elongated holes so that it roughly corresponds to the hole spacing of the worktop 30. Profile 1 with the bolts 9 is then inserted into the worktop 30, with fine adjustment of the bolt spacing if necessary. The bolts are then finally screwed to the profile.

[0026] A thin wooden shim (not shown) is then inserted into the profile as a sacrificial layer and to protect the saw teeth. The workpiece 20 is then placed on top of the shim, aligning or placing it against one of the two profile walls. Depending on whether a saw is used that operates in tension or compression, the workpiece 20 is preferably aligned with the profile wall against which it will later be pressed by the sawing motion.

[0027] The support body 10 is then placed onto the workpiece 20, with the screw of the eccentric clamp 14 being passed through the fastening slot 5 in one of the profile walls. By turning the support body 10, the saw blade 41 can be guided either to the right or left of the support body 10. This typically depends on which side of the workpiece 20 the waste piece is located on or whether the operator is right-handed or left-handed. As a rule, the user of the device will prefer to observe the saw blade on the side of the workpiece that will continue to be used, if necessary together with a marking applied there, in order to align the saw blade and workpiece. If the support body 10 is transparent, the saw blade can be observed on both sides.The saw blade is then inserted into the slots 2 of the profile corresponding to the selected sawing angle 15 or 16 and brought up to the sliding layer on the selected side of the support body 10 and the top of the workpiece. The workpiece 20 is now attracted by the magnets 11, and the saw blade 41 adheres flatly to the sliding layer 12, while remaining movable parallel to it. This allows the sawing movement to be carried out, but angle errors are avoided. Since the sliding layer 12 does not extend to the lower edge of the support body 10, a groove-like recess is created for the laterally protruding saw teeth, and the sliding layer 12 is not damaged during sawing.

[0028] If workpieces are to be sawn for which a U-shaped profile is too wide (e.g. beams), the support body 10 can alternatively be fastened to the L-shaped workpiece stop 18 with the eccentric clamp 14 and then placed on the workpiece 20. The L-shaped workpiece stop 18 also has a slot for this purpose, i.e. it is fastened in the same way as the support body 10 is fastened to the profile wall of the U-shaped workpiece support. The L-profile can be mounted with the short leg resting on the top or bottom, depending on which saw angle 15 or 16 is to be sawn, or on which side of the support body the waste side of the workpiece 20 is to be located, or depending on whether the operator is right- or left-handed.For this application, it is advantageous if the support body also has an integrated or integrable clamping mechanism with which the support body can be fixed to the workpiece, in particular such that the support body 10 is pulled against the workpiece 20 with the workpiece stop 18. One possibility here is, for example, one or more vertical bores in the support body into which a horizontal clamping element is inserted. Alternatively, it is also conceivable to use the same clamping element that is also proposed for the U-shaped workpiece support; i.e., a knurled screw that, in this case, is guided in an abutment that is attached to the support body. List of reference symbols 1 profile 2 slots for saw blade 3 Long hole with countersink 4 countersunk hole 5 Mounting slot for support body 6 bolts 10 support bodies 11 Magnet 12 Sliding surface / system for saw blade 13 threaded hole 14 eccentric clamps 15 saw angle 1 16 saw angle 2 17 fold 18 Workpiece stop 20 workpiece 30 worktop 31 Hole in the worktop 40 saw 41 saw blade

Claims

[1] Device for guiding a saw blade (41) of a hand saw (40) during sawing, comprising a workpiece support and means for guiding the saw blade in a predetermined position relative to a workpiece edge of a workpiece (20) characterized by , • that the workpiece support is formed from a profile (1) extending in the longitudinal direction of the workpiece with at least one horizontally and one vertically oriented contact surface for the workpiece (20), • the profile (1) has one or more slots (2) in the profile wall(s) for inserting the saw blade (41) during sawing, • the saw blade (41) is guided by a support body (10) having a system (12) for the saw blade (41) which can be aligned relative to at least one side of the profile (1) and can be adjusted in height and / or fixed, • the support body (10) with the support (12) for the saw blade (41) and at least one support surface of the profile (1) for the workpiece (20) together define at least one horizontal and / or one vertical saw angle (15 / 16), which is fixed or adjustable, • magnetically acting means (11) integrated with the support body (10) are provided, which exert an adhesive force on the saw blade (41) guided along the system (12) during sawing, • the support body (10) has a cut such as a bevel or a fold (17) running in the sawing direction and facing the saw blade (41) and the workpiece (20), wherein the fold (17) can be formed in particular by a sliding surface (12) fastened to the support body (10) on the saw blade side. [2] Device according to claim 1, characterized bythat the profile (1) forming the workpiece support and extending in the longitudinal direction of the workpiece has a substantially U-shaped or L-shaped or V-shaped cross-section. [3] Device according to one of the preceding claims, characterized by that the device is prepared to be fastened in holes (31) of worktops (30) or lids of tool boxes (30), wherein the fastening is carried out by mounting connecting means to be fastened to the profile (1) in a selection of the holes (31) of the worktop (30), and wherein the connecting means can be cylindrical bolts whose distance from one another can be adjustable. [4] Device according to one of the preceding claims, characterized bythat the support body (10) in interaction with the profile (1) defines a vertical sawing angle of 90° in relation to a horizontal contact surface of the profile (1) and a horizontal sawing angle of also 90° and / or 45° (15 / 16) in relation to at least one vertically oriented contact surface of the profile (1), wherein the profile walls each have corresponding notches for the saw blade (41) to these sawing angles (15 / 16). [5] Device according to one of the preceding claims, characterized by that the support body (10) is replaceable and / or can be supplemented by further systems (12) for the saw blade (41) forming defined sawing angles and / or pivotable to achieve different horizontal (15 / 16) and / or vertical sawing angles. [6] Device according to one of the preceding claims, characterized bythat the support body (10) is reversible, in particular so that the saw blade (41) is guided either on the right or left side of the support body (10) from the operator's point of view and / or the support body (10) is forcibly guided during the height adjustment at a defined angle existing between a horizontal contact surface of the profile (1) and the contact surface (12) for the saw blade. [7] Device according to one of the preceding claims characterized by that the support body (10) is separable from the profile (1) and is prepared to be placed on a workpiece in such a way that it can serve as a guide for a handsaw relative to a selected workpiece edge, and wherein the support body (10) has an integrated or integrable workpiece stop (18) for aligning the support body relative to the selected workpiece edge at least one horizontal 90° and / or 45° angle. [8] Device according to one of the preceding claims, characterized by that the support body (10) is made entirely or partially of a transparent material and allows simultaneous observation of the saw teeth on the side of the saw blade (41) facing the system (12) and the top side of the workpiece, in particular on the saw line. [9] Device according to one of the preceding claims, characterized by that the device has means for fixing the workpiece (20) to the workpiece support (1) or the support body (10). [10] Device according to claim 7, characterized by that the device has means for fixing the workpiece (20) to the workpiece stop (18) or the support body (10).

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