EP2244868A1

EP2244868A1 - Miter saw having a pendulum protective cover

Info

Publication number: EP2244868A1
Application number: EP08871391A
Authority: EP
Inventors: Reiner Schulz
Original assignee: Metabowerke GmbH and Co
Current assignee: Metabowerke GmbH and Co
Priority date: 2008-01-21
Filing date: 2008-11-15
Publication date: 2010-11-03
Also published as: WO2009092411A1; DE202008000873U1

Abstract

The invention relates to a miter saw having a carrier (1) of a mounting (3), and a saw unit (4), wherein the saw unit (4) is attached on the mounting (3) pivotally about a transverse axis (5) and can be pivoted from a raised idle position into a lowered sawing position and vice versa, wherein the saw unit (4) has a saw blade (8), a fixed protective cover (9) encasing the saw blade (8) from the top on part of the circumference thereof, and a pendulum protective cover (10) that can be pivoted about the axis (7) relative to the fixed protective cover (9), encasing the saw blade (8) on part of the circumference thereof from the bottom, and assuming the raised idle position without any manual intervention, preferably under spring force, wherein the pendulum protective cover (10) is in the closing position in the idle position of the saw unit (4) and is pivoted from the idle position into the saw position into an opening position releasing the saw blade (8) on part of the circumference thereof by pivoting the saw unit (4). A control curve (11) is located on the pendulum protective cover (10) on the side of the axis (7) facing away from the mounting (3), said curve interacting with a control lever (14) in order to move the pendulum protective cover (10).

Description

Chop saw with swing protection hood

The invention relates to a chop saw with a swing guard with the features of the preamble of claim 1.

5

Cross-cut saws of the type in question have been known for decades (DE-A-28 29 297, EP-A-1 557 231). They are used to process all types of materials. A special field of application are chop saws in woodworking. But they can also be found for plastics processing and metalworking.

A typical chop saw has a saw unit mounted pivotably about a transverse axis, the saw blade of which is pivotable from a raised rest position into a lowered saw position and vice versa. With this movement of the saw blade, a workpiece located on a workpiece support surface can be cut off - cut off.

However, chop saws are known not only with a saw unit pivotally mounted about a transverse axis, but also with a saw unit which can be pulled longitudinally over the workpiece support surface as so-called radial arm saws.

A cross-cut saw combines the advantages of a pivotable chop saw with those of a radial saw. Moreover, 5 chop saws are usually designed so that they can also execute miter cuts. Details of this can be found in the previously mentioned reference to the prior art, to which reference is hereby made in its entirety. 0 The saw unit of a chop saw of the type in question is normally biased in the direction of the rest position, ie upwards. This is usually done by a spring arrangement, in older chop saws by a kind of counterweight. Contrary to this biasing force, the saw unit is pivoted downwardly on a handle for performing the saw cut until the workpiece located on the workpiece support surface is completely severed. For safety reasons, each miter saw has a pendulum protection cover, which covers the part of the saw blade circumferentially, with which the saw cut is performed in the workpiece when lowering the saw unit. When lowering the saw unit from the rest position in the sawing the pendulum guard 5 is forcibly swung so far that it is opened with a seated on the workpiece support on further lowering the saw unit in the desired extent further. As a result, the best possible security against touching the ring gear of the saw blade is brought about.

l o There is a wealth of solutions for the forced control of the pendulum guard of a chop saw when lowering the saw unit. It is always about ensuring on the one hand the rapid opening of the pendulum hood, on the other to ensure a safe closing of the pendulum hood when pivoting the saw unit and finally the forces

15 as small and uniform as possible.

The initially explained, long-known chop saw has a cable pull control (DE-A-28 29 297). Here, the restoring force for the pendulum guard is applied by a helical tension spring, while the Öffhungsbewegung the 0 pendulum guard is caused by a lever operation. It is not a forced control. In contrast, in the chop saw from which the invention proceeds (EP-A-I 557 231), the Öffhungsbewegung the pendulum guard caused by the swinging down of the saw unit in the sawing. 5

The teaching is based on the problem, a cross-cut saw of the type in question in such a way and further develop that the control of the pendulum protection hood is as even as possible. The above-indicated problem is solved in a chop saw with the features of the preamble of claim 1 by the features of the characterizing part of claim 1.

The control of the pendulum protection hood takes place in the invention Kapp-5 saw in the opening direction, ie from the closed position to the Öffhungsstellung, by the interaction of the control lever with the control cam. Contrary to this movement, the spring element acts.

The spring element according to the invention is arranged so that not only pulls its own spring force the pendulum protection hood in the closed position. For this purpose, the spring element is not simply fixed to the saw unit, but it attacks at its free end between the bearing axis and the axis of the pendulum guard on the control lever. The bearing axis of the control lever is offset relative to the transverse axis of the saw unit arranged so that there is a relative movement of the point of engagement of the spring element on the control lever with respect to the axis of the pendulum guard. This point migrates when pivoting the saw unit in the direction of the rest position away from the axis of the pendulum guard. The pendulum protection hood is thus actively drawn not only by the spring force of the spring element, but also by this removal movement of the point of application of the spring element.

The result is a particularly uniform force curve, which makes working with this chop saw very pleasant.

Preferred embodiments and further developments of the teaching of the invention described above are the subject of the dependent claims.

According to a particularly preferred teaching, it is provided that the bearing axis of the control lever is arranged offset relative to the transverse axis below and towards the axis on the holder. This arrangement of the bearing axis relative to the transverse axis ensures the kinematic conditions that are required for the teaching of the invention. Since the bearing axis is closer to the axis of the pendulum guard than the transverse axis, the pivot radius of each point on the pivot lever is always smaller than the pivot radius of a corresponding point on Sägeag- regreg. The effect achieved is further enhanced by the reduction of the bearing axis relative to the transverse axis. This also results in an angular offset of the pivoting paths. Both together leads to a significant shift of the point of the spring element on the control lever away from the axis of the pendulum guard when pivoting the saw unit. This migration of the point of application supports the tensile function of the spring element with respect to the pendulum protection hood. The pendulum protective hood closes - -

fast and with even force. In the opposite direction, so when opening the swing guard, the force curve is also particularly uniform, because the point of application of the spring element on the control lever moves a little with the spring element.

A particularly expedient positioning of the point of application of the spring element on the control lever is the subject of claim 4.

According to a preferred teaching, it is provided that the control lever rests on the control cam only on one side on the inside. This measure known per se (DE-A-10 2006 002 684) ensures that the pendulum protective hood can be opened manually without hindrance. The control lever then releases its end simply from the control cam.

Another particularly preferred embodiment of the chop saw according to the invention has a control lever equipped with an additional contour. This contour has the effect that initially results in a very fast opening movement of the pendulum guard. The support sits on the rise of the saddle-shaped contour, so that even a slight angular movement of the Sägeaggrega- tes when swinging down from the rest position has a considerable movement of the control lever and its engaging with the cam end result. The pendulum protection hood opens very quickly at first.

In the following the invention will be explained in more detail with reference to a drawing showing only one embodiment. In the drawing shows

1 is a schematic representation of a chop saw,

Fig. 2 shows an exemplary embodiment of a chop saw according to the invention with the saw unit in the raised rest position and

Fig. 3, the chop saw of Fig. 2 with the saw unit in the lowered

Sawing position. Shown in Fig. 1 is a chop saw with a carrier 1, which forms a workpiece support 2. Hatched on the workpiece support surface 2 can be seen here a workpiece, such as a wooden strip. On the carrier 1, a holder 3 is attached, which lies behind the rear of the workpiece support surface 2. This is indicated schematically. The illustrated embodiment shows on the holder 3, a tilt adjustment 3 ', so that miter cuts can also be performed with this chop saw. The introduction to the description and the references cited therein, in which the circumstances of cross-cut saws are described in detail, may be pointed out here.

In the illustrated and preferred embodiment, this is pivotable about a transverse axis 5 and is located above the workpiece support surface 2. In a crosscut and saw the saw unit 4 can in the representation of FIG 1 extending from left to right drawbars, which cantilever from the bracket 3 project over the workpiece support surface 2, are pulled radially, so that the saw cut is longer.

In the illustrated chop saw the saw unit 4 is pivoted about the transverse axis 5 from a raised rest position, which is not shown in Fig. 1, in a lowered saw position, which is shown in Fig. 1, and vice versa.

The saw unit 4 here has a drive motor 6, - a driven by the drive motor 6, on a shaft (geometrically equal to a transverse axis 5 parallel axis 7) mounted saw blade 8, a saw blade 8 from above about half covering fixed protective cover. 9 , A pendulum protection hood 10, which covers the rest, the lower part of the sprocket of the saw blade 8 exposed in FIG.

In Fig. 2 and 3, the saw blade 8 has been omitted in order to better work out the construction of the swing guard 10 can.

2 and 3 show to some extent the "inner life" of the saw unit 4 of the chop saw. Half of the swing hood 10, which is above the plane of the drawing - O -

has been taken away to be able to see inside the chop saw.

It can be seen first that on the pendulum protection hood 10 on the side facing away from the holder 3 side of the axis 7, a control cam 1 1 is arranged. The course of the control cam 11 results from the desired movement of the pendulum guard 10. That may look very different depending on the design of the chop saw. In the illustrated preferred embodiment, it is provided that the cam 11 extends from an axis 7 near the inner end 12 arcuate to a much further away from the axis 7 outer end 13.

To the control cam 1 1 corresponds to a control lever 14 which is hinged to the bracket 3 to a bearing axis 15 pivotally. This extends from the bearing axis 15 to beyond the axis 7 of the pendulum guard 10 to the control cam 11 out. With its end, the control lever 14 is in engagement with the control cam 11. More on that later.

In order to keep the control lever 14 aligned relative to the saw unit 4 in a certain way, a support 16 supporting the control lever 14 is arranged on the saw unit 4, here and according to a preferred embodiment on its fixed protective hood 9. On this is the control lever 14, but this is freely adjustable in the longitudinal direction. In the illustrated embodiment, this edition 16 is a role.

From a comparison of Fig. 2 and Fig. 3 shows the function of the control lever 14 in conjunction with the cam 11. Since the control lever 14 rests on the support 16 and at its in the figures right end by means of the bearing axis 15 on the bracket 3, the swinging down of the saw unit 4 from the recognizable in Fig. 2 rest position leads to the recognizable in Fig. 3 sawing to the fact that the end of the control lever 14, the control cam 1 1 pushes upwards and sideways. This causes the pendulum guard 10 carries out the same movement, which means nothing more than that it is pivoted about the axis 7. The Öffhungsbewegung the pendulum guard 10 takes place against the spring force of this pendulum guard 10 in the direction of the closed position pulling spring element 17. This engages with one end to the pendulum guard 10 below the axis 7, directly or, as here, indirectly via an intermediate power transmission element. With the other end, the spring element 17 engages, again directly or indirectly, on the control lever 14, in an area between the bearing axis 15 and the axis 7. It is important that the spring element 17 according to the invention between the axis 7 and the control lever fourteenth acts. This provides an additional degree of freedom of movement for the end connected to the control lever 14 - point 18 - of the spring element 17th

If the spring element 17 were fastened with the abovementioned end on the saw unit 4 itself, then only the spring force of the spring element 17 would be there to retract the pendulum protective hood 10 into the closed position. Due to the other connection to the control lever 14 results in a superimposed movement of this point 18, which supports the closing movement of the pendulum guard 10.

For this purpose, it is provided in the illustrated embodiment that the bearing axis 15 of the control lever 14 relative to the transverse axis 5 of the saw unit 4 is arranged so that the point 18 of the spring element 17 on the control lever 14 in the rest position of the saw unit 4 is closer to the transverse axis 5 than in the Sawing the saw unit 4.

The previously described conditions are inventively realized in that the bearing axis 15 of the control lever 14 relative to the transverse axis 5 below and to the axis 7 offset towards the holder 3 is arranged. There are other possibilities of arrangement of the bearing axis 15. The arrangement described here has proved to be particularly useful in terms of design and strength.

The illustrated and preferred embodiment shows that the point 18 of the spring element 17 on the control lever 14 here specifically at about 1/3 to 1/5, preferably at about 1/4 of the total distance between the bearing shaft 15 and the with the control cam 11 in engagement standing end of the control lever - o -

14 lies. This position of the point 18 is particularly useful in practice.

Already in the general part of the description has been pointed out that the pendulum guard 10 should be able to be pivoted by hand. This is inventively realized in that the control lever 14 rests against the control cam 11 only on one side on the inside. So you only have a one-sided control of the cam 11th

In the illustrated and preferred embodiment, it is also provided that the control lever 14 at the end of an engaging element 19, in particular a roller, which comes to rest on the control cam 11. Rolling friction is particularly low, so a role at this point is particularly useful.

Also already been explained in the general part of the description is a particular embodiment of the chop saw according to the invention, which can also be seen in the drawing. The control lever 14 has on its underside in the vicinity of the support 16 no straight course, but a kind of wave. Namely, it is provided that the control lever 14, where it rests on in the raised rest position sawing unit 4 on the support 16, a longitudinally in the direction of the transverse axis 5 towards saddle-shaped extending contour 20, with which the control lever 14 during lowering of the saw unit 4 is supported on the support 16. Due to the steep rise of the contour 20 next to the support 16 in FIG. 2, a particularly rapid initial opening movement of the swing protection hood 10 is ensured. At a low angle of the swiveling of the saw unit 4 from the rest position, a large swivel angle of the swing guard 10 is already realized. This ensures a quick opening of the swing guard 10.

The illustrated and preferred embodiment shows that the control lever 14 in the region of the axis 7 of the saw unit 4 is bent like a hook upwards. Thus, the control lever 14 comes in a simple manner on the axis 7 of the saw unit 4 over.

The illustrated embodiment shows the present invention essential spring element 17 as a tension spring, here as a coil spring. This is shown in set and preferred embodiment of the pendulum guard 10 out by means of a bendable connection element, here and according to preferred teaching by means of a connecting strip 21 made of plastic, connected. The terminal strip 21, which could also be described as a kind of band, but also quite a chain or the like. could be in the area of the axis 7 when swinging down the saw unit 4 wound a piece and unwound again when pivoting. For this purpose, it is provided here that the pendulum protection hood 10 has a concentric with the axis 7 arranged ring T on which the terminal strip 21 during the lowering of the saw unit 4 can be wound up. This can be seen in a comparison of FIGS. 2 and 3.

The construction of the invention provides a particularly uniform force curve when pivoting down the saw unit 4 and the subsequent pivoting back into the rest position insofar as the pendulum guard 10 is concerned.

Claims

- Patent claims:

1. Miter saw with a carrier (1) which forms a workpiece support surface (2), a holder (3) on the carrier (1) and one on the holder (3) above the workpiece support surface (2) arranged sawing unit (4), wherein the Saw unit (4) on the holder (3) about a transverse axis (5) pivotally mounted and from a raised rest position in a lowered sawing position and vice versa is pivotable, the saw unit (4) a drive motor (6), one from the drive motor ( 6) about a to the transverse axis (4) parallel axis (7) rotatably driven saw blade (8), a saw blade (8) from above on a part of its circumference encompassing fixed guard (9) and one with respect to the fixed guard (9) about the axis (7) pivotable, in its closed position, the saw blade (8) on a part of its circumference from below encompassing pendulum protection hood (10) and without manual intervention, preferably under spring force, the raised Ruhestellu ng occupies, the pendulum guard (10) in the rest position of the saw unit (4) is in the closed position and pivoted by pivoting the saw unit (4) from the rest position into the saw position in a saw blade (8) on a portion of its circumference releasing opening position is, characterized in that on the pendulum guard (10) on the side facing away from the holder (3) side of the axis (7) a control cam (11) is arranged that on the holder (3) a control lever (14) on a bearing axis (15) is articulated pivotally, which extends beyond the axis (7) to the control cam (11) and is at its end with the control cam (11) in engagement that on the saw unit (4), in particular on its fixed protective hood ( 9), a control lever (14) supporting support (16) is arranged, on which the control lever (14) rests freely adjustable in the longitudinal direction, that pull the pendulum protection hood (10) in the direction of the closed position ndes spring element (17) is provided, which engages one end of the pendulum protection hood (10) below the axis (7) and the other end between the bearing axis (15) and the axis (7) on the control lever (14) engages, and - -

that the bearing axis (15) of the control lever (14) relative to the transverse axis (5) of the saw unit (4) is arranged so that the point (18) of the spring element (17) on the control lever (14) in the rest position of the saw unit (4) closer to the transverse axis (5) than in the sawing of the saw unit (4).

2. Chop saw according to claim 1, characterized in that the control cam (11) from one of the axis (7) near the inner end (12) extends arcuately to one of the axis (7) substantially further away outer end (13).

3. Chop saw according to claim 1 or 2, characterized in that the bearing axis (15) of the control lever (14) relative to the transverse axis (5) below and to the axis (7) offset towards the holder (3) is arranged.

4. chop saw according to one of claims 1 to 3, characterized in that the engagement point (18) of the spring element (17) on the control lever (14) at about 1/3 to 1/5, preferably at about 1/4 of the total distance between the bearing axis (15) and with the control cam (11) engaged end of the control lever (14).

5. chop saw according to one of claims 1 to 4, characterized in that the control lever (14) rests against the control cam (11) only on one side on the inside thereof.

6. chop saw according to one of claims 1 to 5, characterized in that the control lever (14) at the end of an engagement element (19), in particular a roller, which comes to rest on the control cam (11).

7. Chop saw according to one of claims 1 to 6, characterized in that the control lever (14), where it rests in befindlichem in the raised rest position saw unit (4) on the support (16), a longitudinally in the direction of the transverse axis ( 5) towards saddle-shaped extending contour (20), with which the control lever (14) during lowering of the saw unit (4) on the support (16) is supported. - -

8. chop saw according to one of claims 1 to 7, characterized in that the control lever (14) in the region of the axis (7) of the saw unit (4) is bent like a hook upwards.

9. chop saw according to one of claims 1 to 8, characterized in that the spring element (17) is designed as a tension spring, in particular as a helical tension spring.

10. Chop saw according to one of claims 1 to 9, characterized in that the spring element (17) to the pendulum protection hood (10) out by means of a bendable connecting element, in particular a connecting strip (21) is connected.

11. Chop saw according to claim 10, characterized in that the pendulum protective hood (10) has a concentric to the axis (7) arranged ring (7 ¹ ) on which the terminal strip (21) during lowering of the saw unit (4) can be wound.