CN1248192A

CN1248192A - Manually operated electric sawing machine

Info

Publication number: CN1248192A
Application number: CN 98802689
Authority: CN
Inventors: 沃尔夫冈·富克斯; 爱德华·甘泽尔; 乌韦·恩格尔弗里德
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1997-12-19
Filing date: 1998-10-22
Publication date: 2000-03-22
Anticipated expiration: 2018-10-22
Also published as: GB2336128B; CN1100637C; GB2336128A; WO1999032250A1; JP2001512377A; GB9917548D0; DE19756765A1; TW434070B

Abstract

The invention relates to a manually operated sawing machine, especially a precision saw, comprising a machine housing (10), a replaceable saw blade (12) and an electric drive mechanism (11) for driving the saw blade (12) in an oscillating sawing movement, back and forth. The aim of the invention is to considerably simplify the construction of the saw blade drive mechanism (11). To this end, the saw blade (12) is accommodated in a guide mechanism (44) which is variably fixed to the machine housing (10). The saw blade is able to move lengthways, and is directly driven by a drive mechanism (11) in an oscillating movement in said guide mechanism (44).

Description

Electric hand saw cutter

Level of skill

The present invention relates to an electric hand-held sawing machine, in particular a fine-cut saw, of the kind defined in the preamble of claim 1.

In a hand-held saw cutting machine of the type referred to above (DE19625081a1), it has been proposed, in order to allow a quick change of the saw blade without using auxiliary tools, on an oscillating plate which is guided in the machine housing and is driven in an oscillating manner, to mount two chucks on the oscillating plate at a distance from one another in the oscillation direction of the oscillating plate, which chucks can be moved relative to one another in order to change the distance. The two chucks are connected to each other by a connecting device which can be manually operated in order to move at least one of the chucks. The oscillating plate is formed by a U-shaped tool support plate, the legs of which extend between the legs of a U-shaped ball support plate fixed to the machine tool housing. Bearing steel balls are mounted between the mutually opposite legs of the tool support plate and the ball support plate.

THE ADVANTAGES OF THE PRESENT INVENTION

The advantage of the electric hand saw-cutting machine according to the invention with the features of claim 1 is that the use of a saw blade guide independent of the machine and the direct operation of the saw blade by the electric drive results in a greatly simplified saw blade drive, a reduced manufacturing expenditure, a compact machine construction and a reduced height. The complex guide of the oscillating plate slide with the roller bearings is eliminated and replaced by a saw base of very flat construction consisting of the guide and the saw blade, which can be formed as a separate component. The saw base is simply placed and pressed onto the clamping device of the hand-held saw-cutting machine, where the elastic locking provided in the clamping device automatically secures the saw base. In this case, the saw blade is automatically coupled to the electric drive after the saw base has been inserted into the clamping device and the hand-held saw cutter has been switched on or the saw blade has been moved manually in the guide. The saw base changing process can be carried out very quickly and without auxiliary tools, which reduces the auxiliary time.

The electric hand-held saw cutting machine specified in claim 1 can be further advantageously constructed and improved by the measures described in the other claims.

According to a preferred embodiment of the invention, the guide device has a guide rail which at least partially overlaps the blade back of the saw blade facing away from the saw teeth, and two guide legs on each side of the saw blade. The guide rail has a clamping element for inserting the clamping device and has an elongated hole in at least one guide leg extending parallel to the saw blade back, the length of the hole exceeding the sawing stroke. An opening for the positive insertion of a drive pin of an electric drive is formed in the saw blade in line with the at least one elongated hole. The guide rail with the two guide legs can be formed in one piece by a 180 ° bend. In this case, the inside curve is not rounded, but has a missing corner, so that the blade back facing away from the saw teeth does not run against the radius of curvature, thereby avoiding wear and high friction and the consequent heat generation. In another embodiment, the guide rail can also be made in two parts. Here, each guide leg is manufactured separately, and the two guide legs are riveted to each other along the leg edges. The advantage of the two-part solution for the guide rail is a higher process reliability, since no bending is necessary and each guide leg can be individually trimmed. For the free travel of the drive pin, which is inserted in a form-fitting manner into the blade opening, a longitudinal bore in the guide leg, which is aligned in a straight line, is sufficient. However, due to manufacturing tolerances and the possibility of placing the saw base on the clamping device with a 180 ° rotation, at least one elongated hole is provided in each guide leg, wherein the two elongated holes are aligned coaxially, to be precise, arranged one above the other.

According to an advantageous embodiment of the invention, the saw blade is held and guided in the guide rail by means of at least one pin/slot connection, wherein each pin/slot connection has a slot parallel to the back of the saw blade, the slot length exceeding the sawing path, and a pin fixed to at least one leg or a web bent out of the leg, the pin or web projecting into the slot. In the case of a bent-out guide web, the precision of the upper edge of the web to the bent edge must be determined very precisely and must be matched to the saw blade in order to minimize the height play of the saw blade in the guide rail. The guide webs are formed by only one guide leg, so that the height tolerance can be better controlled, the saw blade does not run in the joint between the two guide webs, and the offset of the two guide legs does not play a role. The pin/slot connection makes it possible to limit the travel of the saw blade in the guide rail in the state of being detached from the machine. This is important in order to ensure automatic insertion of the drive pin into the blade opening. The pin/slot connection also limits the vertical clearance of the saw blade in the guide rail.

According to an advantageous embodiment of the invention, a projection and/or a rib projects from the inner surface of each guide leg of the guide rail facing the saw blade, on which the saw blade rests. These projections and ribs minimize the blade friction and ensure a defined, virtually play-free guidance of the saw blade over the entire length of its guide rail. The height of the projections and ribs can be adjusted during manufacture so that saw blades of different thicknesses can be used in the same configuration of the guide rail.

According to an advantageous embodiment of the invention, the guide legs of the guide rail are connected to one another in one piece by a curved edge running parallel to the saw blade back. In the region of the free longitudinal edge of the guide leg facing away from the bent edge, at least one guide section, preferably two guide sections arranged one behind the other at a distance in the sawing direction, is formed by a guide leg, which guide section or guide sections is/are in contact with the other guide leg and is/are fixedly connected thereto, in particular by welding. The saw blade itself here has an opening extending parallel to its blade back, the outlet of which opening is open on the rear blade edge extending transversely to the blade back, the width of the opening being slightly greater than the width of the guide section. The guide device, which is formed by the guide sections on the guide legs and the guide openings in the saw blade and is additionally provided for the pin/slot connection, greatly improves the guiding of the saw blade, in particular when a so-called saw-cutting blade (durchsaegelaette) is used, since in this case the saw blade overlaps the guide rail only over a short region of its blade back. The open mouth of the longitudinally extending opening at the rear transverse edge of the saw blade allows the saw blade to be pushed into the guide rail from the front, and then subsequently to be fixed in the guide rail by bending out the guide webs into the saw blade slots, a limited movement in the sawing direction is possible. The guide rail is welded at four points to the guide section, preventing the guide rail from splitting, in particular at the front transverse edge of the guide rail from which the saw blade projects. The tolerance between the upper edge of at least one guide section and the bottom spacing of the curved edge of the guide rail is the same as the size of the spacing between the upper edge of the saw blade guide opening and the saw blade back, and is small in order to minimize the height play of the saw blade. The two guide sections are formed by only one guide leg, which has the advantage that the saw blade does not run on the joint between the guide sections, the offset of the two bending legs does not play a role, and the height tolerances can be better controlled. Instead of a guide section formed by one guide leg, an intermediate plate of the same width can also be fixed to the inner surface of the guide leg by spot welding.

According to a further embodiment of the invention, the guide rail consists of two separately produced guide legs, wherein either one guide leg is held at a distance by bending and is connected to the other guide leg by welding at the bend, or, in order to achieve a distance between the guide legs, a plate is inserted between the flat and symmetrically constructed guide legs, which plate is welded together with the two guide legs.

According to an advantageous embodiment of the invention, a bag filled with grease is inserted into the bottom of the curved edge in the region of the front transverse edge of the guide rail, from which the saw blade projects and which extends transversely to the curved edge. The pressed-in grease pocket constitutes a grease reservoir from which grease is supplied during the sawing process to the front transverse edge of the guide rail, which constitutes the starting edge of the saw blade, so that friction between the saw blade and the guide rail is minimized. In order not to impair this effect, the starting edge is completely burr-free at least at the two inner edges of the two guide legs facing the saw blade.

According to an advantageous embodiment of the invention, the clamping device has a fastening plate which is fastened to the machine housing and has two locking elements which are arranged at a distance from one another in the sawing stroke direction, one of the locking elements being designed as a suspension hook and the other as a resilient stop plate with an insertion opening. The clamping element on the guide rail has at least one pair of webs, which project from the outside of at least one guide rail and which correspond to the locking elements and are preferably bent away from the guide rail. This results in a very simple, easy-to-handle clamping device which works on the principle of snowboard connection, i.e. front hook and rear hook. If, according to a further embodiment of the invention, a pair of rail webs is provided, which are symmetrical with respect to the center line, the saw blade can be inserted into the clamping device by rotating it through 180 ° in the plane of the saw blade. By means of this, a sawing operation which is flush to the left and right is possible, for which the saw blade with its saw back is completely inserted into the guide rail and is bent in such a way that the saw blade back and the saw tooth bar lie in two planes which are parallel to one another.

If the saw blade according to an advantageous embodiment of the invention is placed with its back only partially in a short guide rail, the sawing depth in the front region of the saw blade can be unlimited. The guide rail has a pair of webs on each guide leg which are adapted to the locking elements of the clamping device and which are arranged symmetrically with respect to the plane of the saw blade. The guide rail is inserted into the clamping device with the web on one guide leg and with the web on the other guide leg, by means of which the saw blade can be turned. Thus, the hand saw cutter operates well with both the left and right hands when working at corners that are difficult to access. When a pair of connecting pieces on one guide leg is omitted, the saw blade can be used for sawing in a right or left flush manner.

According to an advantageous embodiment of the invention, a pin projects from the underside of the fastening plate of the clamping device, which pin, after clamping the saw base in the clamping device, is inserted into mutually aligned bores in the guide legs of the guide rail and projects into an elongated bore of the saw blade, which bore has a length exceeding the sawing stroke and is coaxial with the bore in the guide leg. The pin prevents the guide rail from twisting in the clamping device and the saw blade in the guide rail, in particular when using a saw blade which is only partially located in the guide rail. Furthermore, the pin prevents forces from acting on the stop plate of the clamping device during sawing and thus inadvertently loosening the saw base. In order to insert the pin reliably when the saw base is inserted into the clamping device, the hole in the guide leg is formed as an elongated hole, wherein the clear width thereof in the sawing direction is larger, for example slightly larger, than the diameter of the pin.

According to an advantageous embodiment of the invention, the connection of the pin to the fastening plate is effected by resistance welding or heat riveting. Both methods have the advantage that the high surface hardness of the pin is not influenced to an external extent.

According to an advantageous embodiment of the invention, the drive pin extends substantially at right angles to the plane of the saw base clamped in the clamping device and is guided axially movably and is spring-loaded in the direction of the saw base. The axial guidance of the drive pin, which is of predominantly cylindrical design, takes place in the clamping device fastening plate and in a connecting rod of the drive device, wherein the drive pin has a flange which overlaps a guide element in the connecting rod on the side facing away from the clamping device. The spring, which is designed as a leaf spring and serves for axially loading the drive pin, is prevented from moving axially on the connecting rod by means of a clamping ring.

According to an advantageous embodiment of the invention, the drive pin is guided in the connecting rod in a form-fitting manner and in the fastening plate parallel to the sawing direction, for which purpose an elongated hole is provided in the fastening plate, the length of which exceeds the sawing path and is surrounded by a flange, and the elongated hole is covered by a cover plate surrounding the drive pin. Here, the cover is placed on a felt gasket surrounding the elongate hole flange, which is mainly impregnated with silicone. The advantage of impregnating with silicone is that the felt does not swell and thus the prestress between the cover plate and the fastening plate is kept within calculable limits, which makes it possible to keep the friction generated within limits. The cover plate prevents oil from flowing out through the elongated hole in the fixing plate. Due to the axial displaceability of the drive pin and its spring loading by the leaf spring, the position of the drive pin relative to the saw blade is not important when replacing or placing in the saw holder. If the drive pin does not find a form-fitting opening in the saw blade, it is moved against the leaf spring force. When the electric drive is switched on, the drive pin then runs over the saw blade and automatically enters the saw blade opening under the action of the leaf spring.

According to an advantageous embodiment of the invention, the connecting rod, which is articulated to the disk crank seated on the driven shaft of the drive without relative rotation, is guided on both sides of the front part of its guide drive pin on two bearings, for example guide plates, which are fixed to the machine housing. Therefore, the link cannot be shifted in the front range, so that the saw blade is driven straight precisely. The connecting rod is articulated to the crank by means of a rolling bearing, mainly a needle bearing, and a snap ring placed in a shaft groove prevents the connecting rod from sliding off the driven shaft of the transmission.

According to an advantageous embodiment of the invention, the vibrations caused by the saw blade are reduced by means of a counterweight, which is coordinated in particular with moving objects, i.e. saw blades, connecting rods, drive pins, etc. The counterweight is mounted in the machine housing so as to be longitudinally displaceable and is driven by a connecting rod for an oscillating movement, which is rotatably mounted on an eccentric wheel fixedly connected to the driven shaft of the gearbox.

In order to reduce the temperature, according to an advantageous embodiment of the invention, butter bags are inserted at the circumference and bottom of the eccentric. The lubricating film formed is improved by this and the butter is added from the butter bags.

According to an advantageous embodiment of the invention, the connecting rod is axially fixed by means of an annular shoulder on the eccentric and a disk which abuts on its one side against the disk crank. This prevents the connecting rod from tilting during the transmission.

According to an advantageous embodiment of the invention, the counterweight has a projecting pin which is slidably received in a connecting rod bore, wherein the connecting rod bore has a lead-through projecting in the direction of the counterweight. By means of this lead-through, the guide length or engagement length between the connecting rod and the pin of the counterweight is greater, the point of force action being closer to the counterweight and the occurring moment being reduced.

According to an advantageous embodiment of the invention, the guiding of the counterweight is performed by means of a fixing spring mounted in the machine housing, which fixing spring overlaps the upper and lower side of the counterweight with its two spring legs. At the same time, the fixing spring also guides the counterweight on its side edges. The counterweight can be secured against linear movement by fixing it transversely to the sawing direction. The retaining spring is preferably inserted into the housing of the machine tool and is fixed in the machine tool housing by means of a hook. The spring can be fixed to ensure tolerance compensation between the parts and thus gapless operation of the counterweight.

In a further embodiment of the invention, the guiding of the counterweight is performed by four U-shaped bent parts inserted into the housing instead of the fastening spring. For axial guidance, instead of four U-shaped bends, four needle rollers can be used, wherein the height guidance is provided by ribs of the housing.

Drawings

The invention is explained in detail in the following description with the aid of embodiments illustrated in the drawings. Wherein,

FIG. 1: a longitudinal cross-sectional view of the electric power hand-held machine saw,

FIG. 2: a cross-sectional view taken along line II-II in figure 1,

FIG. 3: according to figure 1a perspective view of a part of a machine housing with a counterweight,

FIG. 4: a bottom view of an eccentric in the machine tool according to fig. 1 in the direction of the arrow IV in fig. 5,

FIG. 5: a cross-sectional view taken along line V-V in figure 4,

FIG. 6: a top view of one of the links of the machine tool of figure 1 in the direction of arrow VI in figure 7,

FIG. 7: a cross-sectional view taken along line VII-VII in figure 6,

FIG. 8: figure 1 is a bottom perspective view of a saw base of the machine tool,

FIG. 9: in figure 8 a top perspective view of the saw base,

FIG. 10: a cross-sectional view along line X-X of the saw base in figure 8,

FIG. 11: a view of part XI of the saw base of figure 9 shown in longitudinal section,

FIG. 12: a partial view of the saw base of figure 9 shown in longitudinal section,

FIG. 13: along the section line XIII-XIII in figure 9,

FIG. 14: according to another embodiment a saw base with saw blade is provided with a perspective view,

FIG. 15: the saw cutting machine of figure 1 is provided with the saw base of figure 14 and has an enlarged part view,

FIG. 16: figures 1 and 15 are enlarged perspective views of the stop plate,

FIG. 17: a schematic view of the modified saw base with saw blade as in figure 14,

FIG. 18: figure 17 is a top view of the saw base guide rail,

FIG. 19: a cross-sectional view along line XIX-XIX of figure 18,

FIG. 20: figure 19 is an enlarged schematic view of part XX,

FIG. 21: in a cross-sectional view taken along line XXI-XXI in FIG. 19,

FIG. 22: figure 21 is an enlarged schematic view of detail XXII,

FIG. 23: fig. 17 is a top view of a saw blade of the saw base.

Description of the embodiments

The electric hand-held saw cutting machine shown in longitudinal section in fig. 1 and in cross section in fig. 2 has a machine housing 10, an electric drive 11 accommodated in the machine housing, and a replaceable saw blade 12 which can be driven by the electric drive 11 into an oscillating reciprocating sawing movement, wherein the saw blade performs a predetermined sawing stroke. The electric drive 11 has a motor 13, which is designed as a commutator motor and has a motor shaft 14, on which a fan wheel 15 is mounted in a rotationally fixed manner, and a bevel gear drive 16, the output shaft 17 of which is at right angles to the motor shaft 14. The motor shaft 14 has a spur gear 18 on the end side, which meshes with a crown gear fixedly connected to the output shaft 17. Thus, a large tolerance is allowed in the axial movement of the motor shaft 14, which can reduce the manufacturing cost of the drive device. An eccentric 20 and a disk-shaped crank 21 are fixedly mounted on the driven shaft 17 with the driven shaft. A connecting rod 22 is articulated to the crank 21, and a drive pin 23 for the saw blade 12 is accommodated in the region of the front end of the connecting rod in an axially displaceable manner. For the articulation of the connecting rod 22, a bearing pin 24 extending parallel to the output shaft 17 is fixed in the crank 21, which bearing pin stands at right angles from the crank 21. The connecting rod 22 is mounted on the bearing pin 24 with a bearing bush 25 and is prevented from sliding out axially by means of a snap ring 26 which is inserted into a shaft recess, wherein the snap ring 26 can optionally also be omitted. Rolling elements 27 (needle bearings) are interposed between the bearing pin 24 and the bearing bush 25. Sliding bearings may also be used instead of rolling bearings. The connecting rod 22 is guided on both sides in its front section, which receives the drive pin 23, in two guide plates 28 (fig. 2) which are fixed to the machine housing 10, so that the drive pin 23 is moved precisely in a straight line and the connecting rod 22 is not deflected upwards.

The eccentric 20 shown enlarged in fig. 4 and 5 has a connecting rod 29 mounted on its outer circumference for the oscillating drive of a counterweight 30. The connecting rod 29 runs on an upper annular shoulder 201 of the eccentric 20 and on a disk 31 arranged between the eccentric 20 and the counterweight 30. As can be seen in fig. 4, grease pockets 202 are introduced on the underside of the eccentric 20 facing the washer 31, by means of which the lubricating film formed is improved and grease is added from these grease pockets 202. The link 29 is prevented from tilting during transmission by the annular shoulder 201 and the washer 31. The blind hole 203 in the underside of the eccentric 20 and the pin 301 on the crank 21, which is inserted into the hole 203, ensure that the eccentric 20 is mounted in the correct position, so that the counterweight 30 works exactly in balance with the saw blade 12. The link 29, shown enlarged in fig. 6 and 7, slidably receives a pin 302 (fig. 1 and 3) extending from the counterweight 30 within a bore 291 in its forward portion, the pin 302 being configured to be integral with the counterweight 30 or pressed into the counterweight 30. As can be seen in fig. 7, the bore 291 has a lead-through 292 which projects in the direction of the counterweight 30, by means of which the guide length or the engagement length between the connecting rod bore 291 and the counterweight 30 pin 302 is greater, and by means of which the force application point is also close to the counterweight 30, the occurring torque is reduced.

The counterweight 30 is mounted in the machine housing 10 axially displaceable in the sawing direction. If the x-coordinate coincides with the sawing direction, the counterweight is supported not only in the z-coordinate but also in the y-coordinate, as can be seen from the perspective view in fig. 3. Here, the support is provided by means of 4 fastening springs 32 which are pressed into the machine housing shell 101 and fastened in the machine housing 10 by means of hooks 321. The position of the holding spring 32 is limited precisely in the y direction by the contact surface formed in the machine housing 10. The holding spring 32 overlaps the counterweight 30 on its upper and lower side with two spring legs 322 and bears with bias against this. By means of these fastening springs 32, not only is tolerance compensation ensured between the components, but also play-free operation of the counterweight 30 is ensured. The counterweight 30 surrounds the disk crank 21 with an oval opening 57.

In order to clamp the saw blade 12 in an exchangeable manner, a clamping device 33 is formed on the machine housing 10. The clamping device 33 has a fastening plate 34, which is shown enlarged in fig. 15, and is fastened to the machine tool housing 10. On the lower side facing away from the machine housing 10, on the fastening plate 34, two locking elements are arranged at a distance from one another in the sawing stroke direction, one of which is designed as a suspension hook 35 and the other as a resilient stop plate 36 (halfblech) with an insertion opening 361 (fig. 16). The stop plate 36 is movably inserted into a hole 341 formed in the fixed plate 34 and is loaded in the direction of the hook 35 by a spring 37 supported on the stop plate 36 and the fixed plate 34. The stop plate 36 has a freely projecting leg 362, by means of which the stop plate 36 can be pivoted in the direction of the arrow 38 in fig. 15 against the force of the spring 37. A pin 39 projects from the underside of the fastening plate 34, which pin is inserted into a bore of the fastening plate 34 and is connected to the fastening plate 34 by resistance welding or hot riveting. The function of the pin 39 having a high surface hardness will be described below.

As can be seen from fig. 2, the drive pin 23 driving the saw blade 12 is guided in the hole 221 of the connecting rod 22 and the elongated hole 40 in the fixing plate 34. Here, the elongated hole 40 (fig. 15) has a length that exceeds the sawing stroke, so that the oscillating reciprocating movement of the drive pin 23 is not hindered by the fixed plate 34. The elongated hole 40 is surrounded by a flange 342 (fig. 15) bent out of the fixing plate 34, on which a felt gasket 41 (fig. 1 and 2) impregnated with silicone is placed. The elongate hole 40 is sealed by a circular cover plate 42 which surrounds the drive pin 23 and moves linearly therewith. Here, the cover plate 42 slides over the felt seal 41, thus sealing the hand-held saw from the outside. By impregnating with silicone, the felt sealing ring 41 can be given a dimensionally precise thickness and, by this, a stress-free arrangement of the connecting rod 22.

For the operation of the hand-held saw-cutting machine, two saw blades 12 are mounted on it, a flush saw blade (fig. 8 and 9), which is bent in such a way that the blade back 121 and its toothed rack 122 lie in two planes parallel to one another, and a so-called saw-cutting blade (durchsaegblatt) (fig. 14 and 15 or 17), which is designed to be flat. The saw blade 12 is mounted in a longitudinally displaceable manner in a guide rail and forms a separate, in particular inseparable assembly with it, hereinafter referred to as saw blade holder or saw base 43, which is designed to be clamped into the clamping device 33 of the machine housing 10. Fig. 8 and 9 show the saw base 43 for left and right flush saws, and fig. 14, 15 and 17 show the saw base for sawing off the saw blade, respectively.

In the embodiment of fig. 8 and 9, the guide means are formed by a guide rail 44 which overlaps the blade back 121 of the saw blade 12 over the entire length of the saw blade and which has two

guide legs

441 and 442 on each blade side. In the embodiment shown, the guide rail 44 is integral, and the two

guide legs

441, 442 are connected to each other by a curved edge 443. The two guide

legs

441, 442 may alternatively be manufactured as separate parts and subsequently joined to each other along the longitudinal edges, for example by riveting, welding or the like. The saw blade 12 is fixed in the guide rail 44 by means of two pin/slot connections arranged symmetrically with respect to the center line 60 of the saw base 43 and is guided in a limited longitudinally displaceable manner. Each pin/slot connection is composed of a slot 58 (see fig. 23) in the saw blade 12, which is shown here by dashed lines, which extends parallel to the blade back 121, and a guide web 45 which is bent out of the spring leg 441 and into the slot 58. This pin/slot connection limits the travel that the saw blade 12 can travel within the guide track 44 in the removed condition of the hand saw cutter, and also limits the vertical clearance of the saw blade 12 within the guide track 44. The slot length of the two slots 58 in the saw blade 12 is here chosen to be slightly longer than the sawing stroke of the saw blade 12. As can be seen from the sectional view in fig. 10, projections 46 and ribs 47 project on the inner surface of the guide legs 441, on which the saw blade 12 rests. The same is true of the inner surface of the guide leg 442. The height of the projections 46 and ribs 47 are adjustable during manufacture so that different thicknesses of the saw blade 12 can be accommodated using the same guide 44. The cams 46 and ribs 47 minimize the friction of the saw blade 12 in the guide rails 44 and ensure a defined, virtually play-free guidance of the saw blade 12 over its entire length. In order to avoid rubbing of the saw blade 12 against the curved edge 443, the corner of the curved circle in the curved edge 443 is omitted (freigespart), so that the edge of the blade back 121 runs unloaded over the radius of curvature of the curved edge 443. The omitted corners are designated 59 in fig. 13. Fig. 13 also shows that instead of the cam 46 and the rib 47, an intermediate plate 56 can also be fastened to the inner surfaces of the

guide legs

441 and 442, respectively, which intermediate plate can assume a sliding function for the saw blade 12. Proper selection of the material for the intermediate plate 56 minimizes blade friction and reduces wear.

In the two

guide legs

441, 442, two pairs of

elongated holes

48, 49, which are aligned with one another and have a length which exceeds the sawing stroke, are formed parallel to the blade back 121. Here, the

elongated hole

48 or 49 in each

guide leg

441, 442 is again arranged symmetrically with respect to the center line 60. In the saw blade 12, an opening 50 for the form-fitting insertion of the drive pin 23 is formed in line with each pair of oblong holes 48, 49 (see fig. 2). The two openings 50 in the blade 12 are again symmetrically disposed about the centerline 60. Furthermore, two holes 51 are arranged in the guide leg 441 symmetrically to the center line 60 and two holes 52 are arranged in the guide leg 442, which are coaxial with the holes 51. The

holes

51 and 52 are intended to receive the pins 39 (fig. 15) projecting on the fixed plate 34 when the saw holder 43 is inserted in the clamping device 33. To ensure that the pin 39 is inserted without problems, the clear width of the

holes

51, 52 in the sawing direction is slightly larger than the diameter of the pin 39, so that the

holes

51, 52 are slightly oval. In the region of the

holes

51, 52, in each case an elongated hole 53 is formed in the saw blade, the length of which exceeds the sawing stroke (fig. 12 and 23), so that the sawing stroke is not impeded by the pins 39 inserted into the

holes

51, 52.

In order to clamp the saw base 43 in the clamping device 33 of the hand-held saw cutting machine, a clamping element is formed on the guide rail 44. In the embodiment of fig. 8-10, the clamping element has two pairs of

coupling tabs

54, 55, which are arranged symmetrically with respect to the center line 60 on the guide legs 441. Here, each connecting piece 54 is bent at the end of the guide leg 441 and each connecting piece 55 is cut out and bent out of the guide leg 441 near the center line. The clamping device 33 operates on the ski-to-board principle, as shown in fig. 15 by the dashed lines, in which the saw base 43 is suspended by a web 55 in the hook 35, and the associated web 54 is pushed downward into its insertion opening 361 by the spring-out action of the stop plate 36. After the spring-back of the stop plate 36, the saw base 43 is positively fixed to the lower side of the fixed plate 34 by the hook 35 and the stop plate 36. The pins 39, which are inserted into the

openings

51 and 52 on the underside of the fastening plate 34, prevent the guide rail 44 and the saw blade 12 from twisting in the guide rail 44, in particular when a sawing blade is used, and prevent a force from acting on the stop plate 36 during sawing and pressing it out in the direction of releasing the clamping device 33. By rotating the saw base 43 in the plane of the saw blade 12, it is possible to cut the saw base 43 according to fig. 8 and 9 flush to the right and left, for which purpose a pair of

webs

54, 55 and a further pair of

webs

54, 55 on the guide legs 441 of the guide rail 44 are suspended in the clamping device 33. Since all the

necessary holes

51, 52,

elongated holes

48, 49, openings 50 and elongated holes 53 are arranged in the saw base 43 in two positions, i.e. symmetrically with respect to the center line 60, the saw base 43 works in the same way with the hand-held saw cutter in both pivoting positions.

When using the saw base 43 with the saw blade 12 shown in fig. 14 and 15, the saw blade 12 is not bent, but rather is designed to be flat, but rather with its blade back 121 partially inserted into the guide rail 44. There is only one of the

elongated holes

48, 49 and 51, 52 in the

guide legs

441, 442 and the opening 50 and the elongated hole 53 in the saw blade 12. A pair of

webs

54, 55 is always formed on each

guide leg

441 and 442, so that the saw base 43 can be inserted into the clamping device 33 with the guide leg 441 on the one hand and with the guide leg 442 on the other hand. Thus, the hand saw can be operated optimally with both left and right hands in corners that are difficult to access. The other structure of the saw base 43 is the same as described above.

In fig. 17-23, a saw base 43 is illustrated with a saw blade 12, which is an improvement over the saw base 43 of fig. 14 and 15. The saw blade 12 is guided in an axially limited movement in the guide track 44 between the

guide legs

441, 442 which are connected to one another by a bent edge 443. Since the guide rail 44 only partially overlaps the back 121 of the saw blade 12, in order to improve the guidance of the saw blade 12 in the guide rail 44, two further guide sections 64 are formed on the guide leg 441, which are arranged one behind the other in the sawing direction at a distance from one another, in addition to the pin/slot connection consisting of the slot 58 in the saw blade 12 and the guide web 45 bent out of the guide leg 441. Here, it is configured in such a way that the guide section 64 rests against the inner surface of the other guide leg 442. Each guide section 64 is welded to a guide leg 442 with two weld points. This welding of the guide rail 44 ensures that the guide rail 44 does not split at its two sides facing away from the bent edge 443, mainly at the outgoing front part of the saw blade. The guide section 64 formed from the spring leg 441 can be seen in particular in the enlarged views of fig. 19 and 20. In order to prevent the saw blade 12 from running in the region of the joint between the guide sections 64 and the guide webs 45, the two guide sections 64 together with the guide webs 45 are formed by identical guide legs 441, the possible offset of which does not play a role and the height tolerance of the saw blade 12 in the guide rail 44 can be better controlled. An opening 65 (fig. 23) in the saw blade 12 interacts with two guide sections 64, which opening extends parallel to the blade back 121 and in order to insert the saw blade 12 into the guide rail 44, the rear blade edge 123 extending transversely to the blade back 121 is free. The width of the opening 65 is slightly greater than the width of the guide section 64 so that the saw blade 12 has clearance on both sides of the guide section 64. The spacing of the upper edge of the opening 65 from the blade back 121 and the spacing between the upper edge of the guide section 64 and the bottom of the curved edge 443 of the guide track 43 must be precisely determined to minimize the height clearance of the saw blade 12 in the guide track 44. Through the open free rearward exit, the saw blade 12 can be pushed from the front into the finished guide 44. The saw blade 12 is longitudinally displaceably fixed in the guide rail 44 by bending the guide webs 45 into the slots 58 in the saw blade 12 next to the guide legs 441.

In a further variant embodiment of the saw base 43, which is not shown, the guide segments 64 are replaced by at least one intermediate plate which rests against the inner surfaces of the two

guide legs

441, 442 and is fixed thereto by means of weld points and forms a bearing surface or guide for the saw blade 12. By means of this intermediate plate, the height play with respect to each saw blade can be adjusted during the mounting process and by means of its free material selection, a higher guide stiffness can be adjusted compared to the saw blade 12.

As with the saw base shown in fig. 8 and 9 and 14, the saw blade 12 rests with its blade surface on ribs 47 (fig. 21) which are formed from the

guide legs

441, 442 and which project on the inner surfaces of the

guide legs

441, 442, within the guide rail 44. The height of the ribs 47 is adjustable during manufacture so that the same guide rail 44 can be used to accommodate saw blades 12 of different thicknesses. The ribs 47 can minimize the friction of the saw blade 12 in the guide 44, in order to avoid a high friction of the saw blade 12 on the curved edge 443, in which case the corners of the curved circle in the curved edge 443 are also freely omitted. Thus, the sides of the blade back 121 are not loaded within the bend radius of the curved sides 443. The blanking is performed in the same manner as shown in fig. 13. To further reduce friction, a bag 66 filled with grease is placed in the bottom of the curved edge 443 (fig. 22) of the guide track 44 at the location of the front transverse edge 444 of the guide track 44 extending transversely to the curved edge 443, which transverse edge 444 constitutes the so-called starting edge for the saw blade 12 and from which the saw blade 12 projects. The grease reservoir in the grease bag supplies grease to the front transverse edge 444 of the guide rail 44 during the sawing process and is responsible for good lubrication between the saw blade 12 and the

guide legs

441, 442. It is necessary here that the front transverse edge 444 is completely burr-free at least at the inner edges of the

guide legs

441, 442 facing the saw blade 12.

In order to clamp the saw base 43 in the clamping device 33 on the hand-held saw cutting machine, the clamping lugs 54 and 55 are again formed in the same manner on the two

guide legs

441, 442, so that the saw base 43 can be inserted into the clamping device 33 with the guide leg 441 on the one hand and with the guide leg 442 on the other hand turned through 180 °. For flush sawing, the saw holder 43 has a pair of clamping lugs 54 and 55. Depending on which guide

leg

441 or 442 of the guide rail 44 the web pair is to be removed, a right-or left-hand flush sawing can be carried out.

As explained in the saw base 43 described in fig. 8 and 9, in the saw base shown in fig. 14 or 17, the guide rail 44 can also consist of two guide

legs

441 and 442 which are produced separately, for which purpose, for example, in order to produce a gap between the

guide legs

441 and 442 for accommodating the saw blade 12, one guide leg is bent flat near the guide rail back, with its bent portion abutting against the other guide leg and is connected to this guide leg inseparably by means of a welding point. The advantage of such a two-part guide rail 44 is that the overall process is highly reliable, since on the one hand the bends made in the one-piece guide rail 44 are dispensed with and on the other hand each guide leg can be adjusted itself. In contrast, a one-piece guideway with curved edges 443 has the advantage of low installation costs and all functions are concentrated on one component and is the best solution in terms of ergonomics and appearance.

In the two-part guide 44 described above, the two

guide legs

441 and 442 can also be made as flat, symmetrical half-plates. In this case, in order to create a spacing between the

guide legs

441 and 442, at least one narrow plate is inserted in the guide rail back region at the upper part between the

guide legs

441 and 442 and welded together with the

guide legs

441 and 442. The inward longitudinal edges of the plate then form the upper support points or guides for the saw blade, which can be optimized by the free choice of the material of the plate to be welded in. For the lower guidance of the saw blade 12 through its opening 65, at least one lower plate is placed between the two

guide legs

441 and 442 at a suitable distance from the upper plate and welded together with them. The guidance of the saw blade 12 can also be optimized here by a free choice of the material of the plate.

Claims

1. An electric hand-held saw cutting machine, in particular a precision cutting saw, having a machine tool housing (10), a replaceable saw blade (12) and a drive (11) accommodated in the machine tool housing (10) for driving the saw blade in an oscillating, reciprocating sawing movement (sawing stroke), characterized in that,

the saw blade (12) is accommodated so as to be longitudinally displaceable in a guide device which is exchangeably fastened to the machine housing (10), the drive device (11) acting directly on the saw blade (12).

2. The hand-held saw cutter of claim 1,

the saw blade (12) and the guide form a single, in particular indivisible, component (saw base 43) which is designed to be clamped in a clamping device (33) fixed to the machine housing (10).

3. The hand-held saw cutter of claim 2,

the guide device has a guide rail (44) which overlaps at least partially a blade back (121) of the saw blade (12) facing away from the sawtooth web (122), the guide rail (44) having two guide legs (441, 442) on each side of the saw blade, the guide rail (44) having a clamping element for insertion into the clamping device (33) and at least one elongated hole (48, 49) which extends parallel to the blade back (121) on at least one of the guide legs (441, 442) and whose hole length exceeds the sawing path, at least one opening (50) for the form-fitting insertion of a drive pin (23) of the drive device (11) being formed in the saw blade (12) in line with the at least one elongated hole (48, 49).

4. The hand-held saw cutter of claim 3,

the saw blade (12) is fixed in the guide rail (44) by means of at least one pin/slot connection and is guided in a longitudinally displaceable manner, wherein the pin/slot connection has a slot (58) extending parallel to the saw blade back (121) and having a slot length exceeding the sawing path, and a pin fixed to at least one guide leg (441, 442) or a web (45) bent out of one guide leg (441) and inserted into the slot (58).

5. A hand-held saw cutting machine according to claim 3 or 4, wherein,

on the inner surface of each guide leg (441, 442) facing the saw blade (12), a projection (46) and/or a rib (47) is/are raised, on which the saw blade (12) rests.

6. A hand-held saw cutting machine according to claim 4 or 5,

the guide legs (441, 442) of the guide rail (44) are held at a distance by a bend of at least one guide leg running parallel to the saw blade back (121) or an insert or a bent edge (443) between the guide legs and are connected to each other at their contact points by welding or integrally, in the region of the free longitudinal edges of the guide legs (441, 442), at least one guide section (64) is formed by one guide leg (441) or at least one guide intermediate plate is fixed, which rests on the other guide leg (442), and is fixedly connected with the guide leg especially by welding points, the saw blade (12) is provided with a longitudinal opening (65) extending parallel to the saw blade back (121), the opening is freely open at a rear blade edge (123) extending transversely to the blade back (121), the width of the guide plate is slightly wider than the width of at least one guide section (64) or guide intermediate plate.

7. A hand-held saw cutting machine according to any one of claims 2 to 6 wherein,

the clamping device (33) has a fastening plate (34) which is fastened to the machine housing (10) and has two locking elements which are spaced apart from one another in the sawing direction, one of the locking elements being designed as a suspension hook (35) and the other as a resilient stop plate (36) having an insertion opening (361). The clamping element on the guide rail (44) has at least one pair of webs (54, 55) which project from the outer side of at least one guide leg (441, 442) of the guide rail (44) and which are adapted to the locking element and which are bent out of the at least one guide leg (441, 442) in particular in one piece.

8. The hand-held saw cutter of claim 7,

the stop plate (36) is movably inserted into a hole (341) formed in the fastening plate (34) and is acted upon by a spring (37) supported on the stop plate (36) and the fastening plate (34) in the direction of the hook (35).

9. A hand-held saw cutting machine according to claim 7 or 8,

the arrangement of the locking element on the fastening plate (34) and the arrangement of the at least one pair of coupling lugs (54, 55) on the at least one guide leg (441, 442) are coordinated in such a way that after one coupling lug (55) has been inserted into the hook (35), the other coupling lug (54) can engage into its receptacle (361) under the elastic retraction of the locking plate (36).

10. The hand saw cutter of any one of claims 7 to 9,

a pin (39) projects from the underside of the fastening plate (34) and, after the saw base (43) has been clamped in the clamping device (33), is inserted into the aligned holes (51, 52) in the guide legs (441, 442) and into an elongated hole (53) in the saw blade (12) which is coaxial with the holes (51, 52), in particular, the clear width of the holes (51, 52) in the sawing direction being slightly greater than the diameter of the pin (39).