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 (1) 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 groove-shaped profile (1) extending in the longitudinal direction of the workpiece with at least two contact surfaces for the workpiece (20), • the workpiece support 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 support body 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 the workpiece support for the workpiece (20) together define at least one horizontal and / or 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, in order 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 too narrow both 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 repeat accuracy. To make matters worse, these mitre boxes, particularly when 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 out the guide surfaces. The publication DE000008236932U1 describes a mitre box with replaceable sliding surfaces for the saw blade which are nevertheless subject to wear from the interlocking saw teeth.A further disadvantage is that these mitre 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 movement does not result in further inaccuracies.

[0003] 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.

[0004] 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 (1) 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 groove-shaped profile (1) extending in the longitudinal direction of the workpiece with at least two contact surfaces for the workpiece (20), • the workpiece support 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 support body 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 the workpiece support for the workpiece (20) together define at least one horizontal and / or 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.

[0005] Further embodiments emerge from the dependent claims and from the following description.

[0006] 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 sawing 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 multifunctional tables or tool transport cases with perforated panels; this means that no additional clamping is necessary. 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.

[0007] 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 lateral 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 a metallic workpiece, makes sense for the workpiece guide.

[0008] A further embodiment of the invention provides that the workpiece can also be fixed 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.

[0009] 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 support bodies that complement a first support body. Magnetically attaching the additional support bodies to the first support body is an advantageous solution.

[0010] A further advantageous embodiment results from the use of an at least partially transparent support body which enables 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.

[0011] Furthermore, it is intended that the support body can alternatively be used with a workpiece support that is placed on top of 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 which is fastened to the side with which the support body otherwise rests against 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 against a workpiece with this contact surface formed from the profile and rests 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, specifically 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.

[0012] As an alternative to mounting the fixture in holes in worktops or other suitable surfaces with holes, 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.

[0013] 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.

[0014] 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.

[0015] An embodiment of the invention is described below with reference to Fig. 1-6 explained. Fig. Figure 1 shows a top view of a U-shaped profile 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 U-profile rests on a worktop (30) with bores (31). Fig. Figure 2 shows a sectional view of the U-shaped profile (1) with the countersunk hole (4) in the profile base, as well as a bolt with an internal thread (6) attached to the underside of the profile via the countersunk hole (4) – the fastening screw is not shown here. 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. Figure 4 shows a sectional view of the U-shaped profile (1) which is inserted or fastened in the bore (31) of the worktop (30) by means of the bolt (6), a workpiece (20) lying in the profile, and the support body (10) which is fastened to a profile wall by means of the eccentric clamp (14) through one of the fastening slots (5). Furthermore, two magnets (11) fastened in the support body (10) are shown, which in turn are covered by the sliding layer (12) (the magnets in the second contact surface which are behind it from this perspective are not shown here). The sliding layer (12) is flatter than the support body (10) and is fastened centrally on the support body (10), resulting in a bevel (17) below and a bevel (17) above. Fig. 5 shows a top view of the U-shaped 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), whereby 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 for the workpiece (20).

[0016] The device can be operated as follows: First, at least two bolts (9) are loosely attached to the underside of the U-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). The U-profile with the bolts (9) is then inserted into the worktop (30), finely adjusting the bolt spacing if necessary. The bolts are then finally screwed to the profile.

[0017] A thin wooden base (not shown) is then inserted into the U-shaped profile as a sacrificial layer and to protect the saw teeth. The workpiece (20) is then placed on top of the base, 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.

[0018] The support body (10) is then placed on 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 on and 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, possibly 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.

[0019] The saw blade is now inserted into the slots (2) of the U-profile that match 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 flat to the sliding layer (12) while remaining movable parallel to it. This allows the sawing movement but avoids angular errors. Because the sliding layer (12) does not extend to the lower edge of the support body (10), a fold-like recess is created for the laterally protruding saw teeth and the sliding layer (12) is not damaged during sawing.

[0020] If workpieces are to be sawn that are too wide for the U-profile (e.g. beams), the support body (10) can alternatively be fastened to the L-shaped workpiece stop (18) using 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 sawing 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 in such a way that the support body (10) is pulled against the workpiece (20) with the workpiece stop (18). One idea here is, for example, one or more vertical holes 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 which in this case is guided in an abutment that is attached to the support body. List of reference symbols 1 workpiece support / U-profile 2 slots for saw blade 3 Slotted 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 / L-profile 20 workpiece 30 worktop 31 Hole in the worktop 40 saw 41 saw blade QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 000008236932U1

[0002]

Claims

[1] Device for guiding a saw blade (41) of a hand saw (40) during sawing, comprising a workpiece support (1) 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 groove-shaped profile (1) extending in the longitudinal direction of the workpiece with at least two contact surfaces for the workpiece (20), • the workpiece support 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 support body 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 the workpiece support for the workpiece (20) together define at least one horizontal and / or 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 by that the groove-shaped profile (1) 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 workpiece support (1) is prepared to be fastened in the holes (31) of worktops (30) or lids of tool boxes (30), whereby the fastening can be effected by means of bolts (6) which are fastened to the underside of the workpiece support (1) and engage or are inserted into the holes (31), whereby their distance from one another can be adjustable. [4] Device according to one of the preceding claims, characterized by that the support body (10) in interaction with the workpiece support defines a vertical sawing angle of 90° in relation to the bottom of the profile (1) and a horizontal sawing angle of also 90° and / or 45° (15 / 16) in relation to at least one side wall 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 by that 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 positively guided at a defined angle between the profile base and the contact surface during the height adjustment. [7] Device for guiding a saw blade (41) of a hand saw (40) during sawing, comprising means for guiding the saw blade (41) in a predetermined position relative to a workpiece edge of a workpiece (20) characterized by , that • the saw blade (41) is guided by a support body (10) having a system (12) for the saw blade (41), • the support body (10) is prepared to be placed on the workpiece and has a workpiece stop (18) for aligning the support body relative to a workpiece edge, • the support body (10) with the support (12) for the saw blade (41) and the workpiece stop (18) together define at least one horizontal and / or 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) and / or the fold (17) is formed by a sliding surface (12) fastened to the support body (10) on the saw blade side. [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 upper side of the workpiece, in particular on the sawing 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 workpiece stop (18) or the support body (10). [10] Device for guiding a saw blade (41) of a hand saw (40) during sawing, comprising a workpiece support (1) 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 (1) is formed from a profile extending in the longitudinal direction of the workpiece with at least two contact surfaces for the workpiece (20), • that the workpiece support (20) is prepared to be fastened in the holes (31) of worktops (30) or lids of tool boxes with a plurality of holes (30), • that the fastening is carried out by mounting fasteners attached to the workpiece support (1) into a selection of the holes (31) in the worktop (30).

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