The present invention relates to a flip over saw according to the preamble of claim 1 including a main body having a saw blade driven to rotate and a table at which the main body is held movable up and down, and a base at which the table and the main body are held rotatable 180 degrees. The flip over saw can be used as a miter saw when the main body is positioned over the table, and can be used as a table saw when the main body is positioned under the table protruding the saw blade over the table.

A conventional flip over saw has a rectangular mounting base on which a table is horizontally supported rotatable 180 degrees around a center portion of the table and capable of being secured even if either one or the other surface of the table faces upwardly. Moreover, on one side of the table a main body is pivotally mounted movable up and down, and the main body has a saw blade which rotates driven by a motor. With this configuration, the flip over saw can be used as a miter saw when the main body is positioned over the table, in which the main body is lowered to cut a workpiece disposed on the table. On the other hand, the flip over saw can be used as a table saw when the main body is positioned under the table by rotating the table with a condition that the saw blade is secured at a bottom dead center to penetrate the table downwardly. In a table saw mode, a workpiece on the table can be slid with respect to the saw blade and cutting is conducted. As this kind of flip over saw, the U. S. Patent No. 5787779 discloses a well-known structure.

In such a flip over saw as described in the above patent, a heavyweight motor is located at the rear side of the table when it is used as a miter saw, so that the table is unbalanced and prone to rotate. With this configuration, malfunctional table rotation might damage the table and the main body. In addition, the reverse operation of the table becomes hard since the center of gravity of the table being far from the center of rotation generates a large centrifugal force in reversing, thereby lowering operability.

US 4,531,441, US 3,570,564 and EP 0 271 755 A1 disclose flip over saws which are a combined table and miter saw. By rotating a horizontal table supported on a base the saw can be switched from a miter saw mode to a table saw mode. A main body is supported by a support arm provided on one side of the table and has a saw blade driven to rotate by a motor. The motor is respectively disposed behind the center of rotation of the table with respect to the base when regarded in a cutting direction in the miter saw mode and at a top dead center of the main body.

EP 0 586 172 A2 which forms the preamble of claim 1 discloses a pivoting power tool with a table. The table is pivotable about an axis with respect to a frame, which axis moves along an arc between two end positions which it assumes in the miter saw mode and the table saw mode, respectively. In the miter saw mode and at the top dead center of the main body, the motor which is provided on a support arm is positioned behind the center of rotation.

In order to overcome the above problems, an object of the present invention is to provide a flip over saw which prevents the table's accidental rotation while excellent operability in reversing the table is secured.

In order to achieve the above object, a flip over saw comprising the features of claim 1 is provided. Preferred embodiments are defined by the dependent claims. The present invention is characterized in that

the center of motor is located in front of the center of rotation of the table with the main body being at the top dead center in a miter saw mode in order to prevent the accidental rotation of the table more effectively.

In addition, preferably the main body is pivotally mounted on a support arm via a support shaft rotatably in the upper and lower direction. Then, the distance between the center of rotation of the table and the center of motor is shorter than that between the center of rotation of the table and the center of the support shaft with the main body being at a bottom dead center in a miter saw mode in order to obtain excellent operability in reversing the table from the miter saw mode position to the table saw mode position.

According to the present invention, since the table is well-balanced in the miter saw mode, the table is protected from being reversed even if locking of the table is released by malfunction. As a result, damage to the table and the main body caused by accidental reverse of the table can be prevented. In addition, since the center of gravity is positioned near the center of rotation, the table's reverse operation becomes easier, thereby improving operability.

According to a preferred embodiment of the present invention, reversing of the table for conversion to the table saw mode is conducted by flipping up the front part of the table upwardly. By doing this, the center of gravity is positioned to the front, thereby preventing the accidental reverse of the table from the miter saw mode more effectively.

According to the present invention, since the motor is closer to the center of rotation of the table the moment of inertia in reversing becomes small, so that reversing can be conducted easily with a light pressure. Therefore, an excellent operability can be achieved in reversing the table upon conversion from the miter saw mode to the table saw mode.

• Fig. 1 is an overall view of a flip over saw (in the miter saw mode).
• Fig. 2 is a plain view of the flip over saw.
• Fig. 3 is an explanation view showing a locking state at the bottom dead center.
• Fig. 4 is an explanation view of a flip over saw (in the table saw mode).
• Fig. 5 is an explanation view showing a positional relationship between a motor and a rotating shaft.

Hereinafter, embodiments of the present invention will be explained with reference to the drawings.

Fig. 1 is an overall view showing an example of a flip over saw and Fig. 2 is a plain view thereof. A flip over saw 1 has a base 2 which is a mounting in rectangular shape in a plain view and a table 3 placed on the base 2, and a saw blade unit 4 mounted on the table 3. The table 3 is held rotatable 180 degrees around the rotating shafts 5, 5 extending in the lateral direction (in Figs. 1 and 2, the right is forward). Moreover, the table 3 can be secured in a horizontal state by a stopper mechanism 6 even if either one or the other surface of table 3 faces upwardly. The table 3 also has a circular turntable 7 which is horizontally turnable, and a guide fence 8 parallel to the rotating shaft 5 so as to transverse on the turntable 7.

The saw blade unit 4 has a support arm 9 standing at the rear part of the turntable 7 and a main body 11 held to be movable up and down by a support shaft 10 at the upper end of the support arm 9. At the left side of a blade cover 12 which is a housing of the main body 11, a motor 13 and a handle 14 are provided. In the blade cover 12, a circular saw blade 15 driven to rotate by the motor 13 is provided. The main body 11 is urged toward the top dead center as shown in Fig. 1 by a torsion spring (not shown) provided on the support shaft 10. As shown in Fig. 3, the main body 11 is lowered to the bottom dead center where it penetrates a slit (not shown) provided at the center of the turntable 7 when a handle 14 is held down. Then a workpiece on the turntable 7 can be cut by the rotating saw blade 15. In this way, the flip over saw can be used as a miter saw. The reference number 16 denotes a safety cover which is at the position of covering the saw blade 15 when the main body 11 is at the top dead center and rotated to expose the saw blade 15 in accordance with lowering of the main body 11.

The support arm 9 can be tilted with the main body 11 in the right direction (the lower direction of Fig. 2) on the turntable 7. Fixing the tilted support arm 9 and the main body 11 by a lever 17 at an arbitrary tilting position provides the saw blade 15 with an angle in the perpendicular direction. With the tilt of the main body 11, bevel cutting can be conducted with respect to the workpiece on the turntable 7. Moreover, the turntable 7 can turn in a horizontal direction with the main body 11 when a handle 14 is held down. In accordance with the selected angle of the horizontal turn of the turntable 7, orthogonal cutting and miter cutting can be conducted. In the orthogonal cutting, the saw blade 15 is perpendicular to the guide fence 8. On the other hand, in the miter cutting the saw blade 15 is horizontally slanted from the perpendicular position.

The main body 11 can be secured at the bottom dead center as shown in Fig. 3 by means of a locking mechanism 18 provided between the support arm 9 and the main body 11. As shown in Fig. 4, by reversing the table 3 with this secured condition of the main body 11, a table saw mode can be obtained wherein only the saw blade 15 protrudes above the table 3 on which a workpiece is slid for cutting. In this table saw mode, the rotating shaft 5 corresponds to the center of rotation of the table 3. Here, L1 is defined as the distance between the center of axle O of the rotating shaft 5 and the center O1 of the motor 13, and L2 is defined as the distance between the center of axle O of the rotating shaft 5 and the center 02 of the support shaft 10. Then, L1 is set to be shorter than L2.

In the miter saw mode, the rotating shafts 5, 5 of the table 3 are positioned on the table 3, so that there is a difference in height of the table 3 between at the first rotating position as shown in Figs. 1-3 (the miter saw mode) and at the second rotating position as shown in Fig. 4 (the table saw mode). (The table 3 in the table saw mode is higher.)

Moreover, in order to allow the table 3 to rotate, an opening 19 is provided at the center of the base 2 in the longitudinal direction. In the inner lateral edges of this opening 19, a pair of first stopper rubbers 20, 20 which support the lower surface of the table 3 at the first rotating position are provided on the front side of the opening 19. On the other hand, a pair of second stopper rubbers 21, 21 are provided on the rear side of the opening 19. The second stopper rubbers 21, 21 are positioned on the table 3 at the first rotating position, and support the lower surface of the table 3 at the second rotating position.

With this configuration, the table 3 can be reversed only in the direction where the front part of the table is flipped up (the direction of an arrow in Fig. 3) in converting from the miter saw mode to the table saw mode. On the other hand, the table 3 can be reversed only in the direction in which the rear part of the table is flipped up (the direction of an arrow of Fig. 4) in converting from the table saw mode to the miter saw mode. It should be noted that the rotating shafts 5, 5 are not positioned at the center of the table 3 in the longitudinal direction, but instead at a slightly rearward position in the first rotating position, so that the table 3 does not interfere with the first stopper rubbers 20, 20 upon conversion from the miter saw mode to the table saw mode.

As shown in Fig. 5, in this flip over saw 1, a motor 13 is located adjacent to the upper side of the rotating shafts 5, 5 of the table 3 with the main body being at the top dead center in a miter saw mode where the main body 11 is positioned above the table. According to the invention, the motor's location adjacent to the upper side of the rotating shafts 5, 5 is achieved as follows. When the main body is at the top dead center, the center O1 of the motor 13 is located at the area slightly forward from the vertical surface S penetrating the center of axle O of the rotating shafts 5, 5 of the table 3. Then, the horizontal distance H between the center O1 and the vertical surface S is set to be smaller.

In the flip over saw configured as described above, in the miter saw mode the table 3 is secured by means of a stopper mechanism 6 with the saw blade unit 4 raised as shown in Figs. 1-3. Then the handle 14 is held to lower the main body 11 in which the blade saw 15 is rotating, so that a workpiece disposed on the turntable 7 can be cut, specifically, the bevel cutting by tilting the main body 11 and the miter cutting by horizontally turning the turntable 7 are achieved.

Here, because of the location of the motor 13, the center of gravity of the main body 11 is substantially positioned at the center of the table 3 in the longitudinal direction (that is, adjacent to the rotating shaft 5). Therefore, the accidental reverse of the table 3 can be prevented even if the stopper mechanism 6 is released by malfunction and so on.

On the other hand, conversion into the table saw mode is conducted as follows. First, the main body 11 is lowered to the bottom dead center to be secured by the locking mechanism 18. Then the stopper mechanism 6 is released and the table 3 is turned 180 degrees in the direction where the front part of the table is flipped up until the table 3 is stopped at the reverse position abutting the second stopper rubbers 21, 21. Likewise, upon conversion into the miter saw mode, the table 3 is turned 180 degrees in the direction where the rear part of the table is flipped up until the table 3 is stopped at the reverse position abutting the first stopper rubbers 20, 20. In these reverse operations, the motor 13 of the main body 11 locked at the bottom dead center is further closer to the rotating shaft 5 in addition to above-described location. Consequently, the moment of inertia upon reversing becomes smaller, so that the reverse can be conducted easily with a light pressure.

Since the table 3 is well-balanced even in the miter saw mode, the table 3 is protected from reversing even if the stopper mechanism 6 is released by malfunction. As a result, damage to the table 3 and the main body 11 caused by accidental reverse can be prevented. In addition, since the center of gravity is closer to the center of rotation, reverse operation of the table 3 becomes easier, thereby improving operability.

Moreover, when the main body 11 is at the top dead center in the miter saw mode, the center of gravity is positioned forward since the motor 13's center O1 is positioned in front of the table 3's center of rotation O. As a result, the accidental reverse of the table 3 from the miter saw mode can be prevented more effectively.

On the other hand, when the main body 11 is at the bottom dead center in the miter saw mode, the distance between the table 3's rotating center O and the motor 13's center O1 is shorter than that between the rotating center O and the support shaft 10's center 02. Consequently, the moment of inertia becomes small in reversing the table 3, so that reverse can be conducted easily with a light pressure. Therefore, an excellent operability can be achieved upon reverse of the table 3 to convert from the miter saw mode to the table saw mode.

Further, the structure of the flip over saw is not limited to the above embodiments. The main body capable of tilting to both sides may be applicable to the present invention, and on the contrary, the structure excluding bevel cutting or miter cutting may also be applicable.