Circular saw

A circular saw, the saw blade of which is adapted to be moved horizontally across a table at a horizontally movable carriage or slide and to be lifted into a position above the material to be sawed comprises a horizontal cantilever beam one end of which is guided by a vertical guide means at a single vertical support member and the other end of which is unsupported and therefore offers free access for handling of the material to be sawed or sawed, respectively, and for controlling the saw movements from a space adjacent said other end.

The invention relates to a circular saw, in particular for sawing bars or 
billets of light metal, such as aluminium, the saw blade of which is 
adapted to be moved horizontally across a table at a carriage or slide and 
to be lifted into a position above the material to be sawed, the carriage 
or slide being displaceable along a horizontal guide means. 
In a known circular saw of this kind (German Application Print 2 035 050) 
the saw slide is disposed on a horizontal guide beam adapted be be lifted 
along vertical guide columns by support bearings provided at both its ends 
with the aid of lifting cylinders operating under synchronized control. 
This design is complicated and expensive. The table hardly offers access 
in the area of the circular saw. 
In a further known circular saw (German Patent Application Print No. 26 31 
767) a horizontal cantilever beam which carriers and horizontally guides 
the carriage or slide of the saw may be adjusted by hand in different 
vertical positions at a vertical support member using a screw spindle for 
the adjustment istself and an additional clamping screw for fixing the 
adjusted position at the vertical support member. This does not allow for 
a lifting and lowering of the saw in use during each sawing step. 
Another known construction provides for a protective hood covering the saw 
blade (French patent No. 1 366 911). 
It is an object of the invention to provide a circular saw which overcomes 
the disadvantages mentioned. 
It is a further object of the invention to provide a circular saw which 
permits quick sawing by allowing controlled horizontal and lifting or 
lowering movement of the saw blade during each sawing step. 
Still another object of the invention is to provide a circular saw which 
offers good access to a worker and at the same time protecting the worker 
from being injured by the saw blade. 
A further object of the invention is to provide a circular saw of simple 
structure. 
According to the invention it is provided that the horizontal guide means 
is disposed at a horizontal cantilever beam, one end of which is guided by 
a vertical guide means at a single vertical support member which is fixed 
at least in lifting direction, and the other end of which is unsupported 
and offers free access for handling of the material sawed or to be sawed, 
respectively, and for controlling the saw from the space adjacent of said 
other end. 
According to a further aspect of the invention the horizontal guide means 
is arranged at a horizontal cantilever beam of a support structure 
including a vertical column which is fixed at least in lifting direction, 
the cantilever beam being connected rigidly to said column, and a guide 
means for the lifting movement of the saw blade is provided at the slide 
or carriage. 
The invention provides an improvement of the accessibility of the saw by 
virtue of the cantilever beam construction since the operating side can be 
located at the free end of the horizontal cantilever beam. At the same 
time the lifting movement and its guidance are facilitated, as compared to 
the known circular saw, because both embodiments of the invention require 
only one drive means for the lifting movement instead of two drives 
controlled in synchronism, and only one guide means for the lifting 
movement. 
In accordance with a further aspect of the invention the guidance of the 
lifting movement preferably is also designed similar to the horizontal 
guide means and is embodied in particular in the form of a rectilinear 
roller guide means. However, it is obvious that the lifting movement may 
also be generated by pivoting movement of the saw blade with sawing drive 
relative to the slide. 
In accordance with the invention the lifting movement and the horizontal 
movement may either be effected separately or at the same time. 
The drives of the longitudinal movement and of the lifting movements 
conveniently are realized by separate pressure fluid cylinders. A basic 
adjustment of the lifting movement can be obtained in simple manner by 
connecting the pressure fluid cylinder for the lifting movement to an 
element which is adjustable in height, such as the spindle of a height 
adjustment device, for example, a worm drive adapted to be driven by a 
hand wheel. 
With the circular saw according to the invention the saw blade 
automatically generates a force which presses the material to be sawed 
against the surface of the table and against the abutment. And yet at 
least one additional hold down device is provided for safety 
considerations. It is adapted to be pressed against the material being cut 
by means of its own pressure fluid cylinder, independently of the lifting 
movement of the saw blade. This is preferred over a likewise conceivable 
arrangement with which the hold down device is mounted on the carrier 
which is raised and lowered because in that case the hold down effect 
would be cancelled upon lifting of the saw blade, an effect not always 
desired. 
An important contribution toward increased saftey of the circular saw 
according to the invention resides in the fact that a fixed protective 
hood covering the saw blade in its lowered as well as in its raised 
operating positions is mounted on the table or its support. 
The circular saw according to the invention may also be designed as a 
so-called "flying saw" which means that the otherwise fixed members, such 
as table and support elements are movable together with the material to be 
sawed at the advance speed thereof.

Of the circular saw only the table 1, the saw blade 2 in four positions I, 
II, III, and IV, a longitudinal abutment member 3, a crosscut stop member 
4, and in phantom outline (discontinuous lines) a protective hood 5 are 
shown in the perspective diagrammatic view of FIG. 1. Furthermore, an 
elongated slot 6 may be seen in the table. During the cutting process the 
lower edge of the saw blade 2 enters into this slot. The material to be 
sawed is marked by reference numeral 7. 
With reference to FIG. 1 it will now be described how the novel circular 
saw is put to work: 
Upon infeed of the material to be sawed, in the direction of arrow T, and 
aligning against abutment member 3 and stop member 4 the saw blade is 
caused to rotate in the direction of arrow R and is moved in translatory 
sense from its rest position I in the direction of arrow A parallel to the 
table top 8. During its movement the saw blade 2 completely severs the 
material 7 to be sawed because the lower edge of the saw blade is disposed 
somewhat deeper than the underside of the material 7 to be sawed since it 
is immersed in slot 6. The sawing process is continued until saw blade 2 
has reached position II. Then the material 7 to be sawed is fully severed 
and, for instance, cut to a length 1 which is predetermined by the 
position of the adjustable crosscut stop member 4. Subsequently saw blade 
2 is moved vertically upwards in the direction of arrow B into an elevated 
position III, in which position the lower edge of the saw blade is free of 
the surface of the workpiece or material 7. At this height or elevation 
the saw blade 2 is again moved in translatory sense parallel to the table 
surface from position III into a position Iv which is located beyond the 
longitudinal abutment member 3, as seen from the operator's place shown 
diagrammatically in FIG. 1. During this return motion the operator can 
remove the cut-off part 7' of the material 7 and align new material on 
table 1 to be cut subsequently. It will be appreciated that the saw blade 
is fully covered by protective hood 5, particularly during the return 
motion (arrow C), so that optimum accident protection of the operator is 
obtained when he carries out his work under the protective hood 5. 
The saw blade is then lowered in the direction of arrow D from position IV 
into the rest position I in which it is ready for further operation. 
The embodiment now to be described with reference to FIGS. 2 to 4 is a 
preferred, particularly elegant realization of extremely simple structure 
of the circular saw, the operation of which was explained above with 
reference to FIG. 1. For the sake of simplicity the same reference 
numerals are used for corresponding elements. 
The circular saw shown in FIGS. 2 to 4 again comprises a table 1 with a 
table top 8 and support 9 and an elongated slot 6, a saw blade 2 entering 
into said slot upon sawing and being shown in discontinuous lines in FIG. 
2 in its four positions I to IV, a longitudinal abutment member 3 for the 
material 7 to be sawed, and a stationary protective hood 5 which 
completely covers the saw blade in its raised positions III, IV. 
In FIG. 2 the place of the operator indicated in FIG. 1 is at the left 
side. It will be appreciated that the operator has free access to the 
table top 8 and to the material 7 to be sawed without being unnecessarily 
exposed to any danger from the saw blade which is largely covered by the 
protective hood 5 during operation as well. The good accessibility, among 
others, is afforded by the cantilever type structure of the saw support 
means which is open towards the operator's side and will be described in 
more detail below. 
It may be gathered from FIGS. 2 and 3 that the drive motor 10 of the saw 
blade is arranged coaxially with the saw blade and that the sawing unit 
composed of drive motor 10 and saw blade 2 is supported on a horizontally 
movable carriage 11. The stroke or height of lift by which the saw blade 2 
is to be raised above the surface of the table results from the following 
equation: 
EQU h=x+c+b 
wherein h=height of lift, x=maximum sawing depth (or thickness of the 
material being cut), c=a minor clearance of motion between the underside 
of the drive motor 10 and the surface of the material to be sawed, b=the 
depth of immersion of the saw blade 2 below the surface of the table. 
The radius of the saw blade 2 is determined according to the following 
equation: 
EQU r=h+d 
wherein d=the motor radius in vertical, downwardly oriented direction. The 
useful portion h of the saw blade radius r is as large as can be and much 
greater, for instance, than with a saw having its saw blade arranged under 
the table. 
The circular saw shown in the figures comprises a horizontal cantilever 
beam 12 along which the carriage 11 is horizontally movable together with 
the sawing unit 2, 10. This permits generation of the movements in the 
direction of arrows A and C. The cantilever beam 12 is firmly connected to 
a column 14 which in turn is vertically displaceable in a support member 
15. This permits generation of the movements of the saw blade in the 
direction of arrows B and D. In both cases pressure fluid cylinders are 
employed to produce the movements, one pressure fluid cylinder 16 
generating the vertical movements and one pressure fluid cylinder 17 
(FIGS. 3 and 4) generating the horizontal movements of the saw blade 2. 
The foot of cylinder 16 is firmly connected to the spindle 18 of a worm 
drive 19 provided with a driving worm 20. Rotation of the worm 20 by means 
of a handwheel (not shown) permits adjustment of the basic level of the 
hydraulic cylinder 16 and thus of column 14 to a desired value. As shown 
particularly in FIG. 3, the piston rod 21 of cylinder 16 engages column 
14, designed as a I-beam, by way of a transverse bar 22. Roller pairs 
comprising upper rollers 25 and lower rollers 26 are rotatably supported 
at two different heights on the legs 24 of column 14. The corresponding 
guide rails are formed by round rods 27 fixed at the inner sides of legs 
28 of oppositely arranged U-shaped profiles 29 of support member 15. The 
rollers 25, 26 have rounded recesses 30 to adapt them to the rods 27. 
Also cantilever beam 12 is made from sectional material and in particular 
has a U-shaped profile 32 with its opening oriented downwards, round rods 
34 being secured to the inner sides of its legs 33 in the same manner as 
with the guide means of column 14. The rods 34 serve as rails for roller 
pairs comprising front rollers 35 and rear rollers 36 of carriage 11. 
The guide structure described above is of simple design and permits 
noiseless and maintenance-free guidance of low wear of column 14 inside 
support member 15 and of a carriage 11 in cantilever beam 12. 
The circular saw shown comprises another structural group embodied by two 
devices for holding down the material to be sawed. They each comprise a 
pivotable angular bracket 40 shaped like a gallows. For the sake of 
clarity FIG. 2 shows only parts of the horizontal leg 41 and of the 
vertical leg 42 of said bracket. Each angular bracket is adapted to be 
raised and lowered by means of a pneumatic lifting cylinder 43 (FIG. 3). 
At the free end of the horizontal leg 41 a hold down jaw 44 is arranged so 
as to be adjustable in height by means of a guide bar 45 which is secured 
against rotation. 
It will be appreciated that because of their independent drive the hold 
down devices are operable completely independently of the saw blade 
movement, especially the lifting movement of the saw blade. However, it is 
also possible to couple the operation of the hold down devices with the 
lifting movement of the cantilever beam 12, for example, in such manner 
that the cylinders 43 are operated automatically to lift the hold down 
jaws 44 and thus release the material 7 being sawed when the saw blade 2 
has reached a certain position, such as position II after cutting. 
Another feature of the circular saw shown resides in a chip suction device 
disposed under the table adjacent the work path of the saw and comprising 
a chip suction channel 50 as well as chip discharge passages 51 and 52. 
These discharge passages communicate with a ventilator (not shown) and a 
cyclone separator (likewise not shown). 
The saw as illustrated operates safely and silently as described in 
connection with FIG. 1. The sawing time is reduced by the period of time 
required for the return movement of the saw blade 2 from position III into 
position I because during that period of time the operator can carry out 
other work, such as removing the material cut to the desired length and 
arranging new material to be cut in preparation of the next sawing cycle. 
In the embodiment according to FIG. 5, in which the same reference numerals 
are used for elements corresponding to those of FIGS. 1 to 4, the vertical 
column 14 of the cantilever beam 12 is supported stationarily, thus 
providing increased rigidity of the structure. Whereas in this case, too, 
horizontal guide rails 34 are arranged at the cantilever beam 12 to guide 
the slide or carriage 11 along the cantilever beam 12, vertical guide 
rails 27 are provided at the carriage 11. The sawing unit composed of 
drive motor and saw blade 2 is vertically displaceable along these guide 
rails, for instance, by means of a pressure fluid cylinder (not shown) 
which acts between the carriage 11 and the sawing unit. To realize a 
"flying saw" one should take support member 15 of FIG. 2 or column 14 of 
FIG. 5 as being movable in a direction vertical to the plane of the 
drawing, i.e. in the infeed direction of the material to be sawed at a 
speed corresponding to the advance speed of the material being sawed, 
instead of being stationary. 
Though the above-described embodiments are preferred, many other 
modifications and refinements which do not depart from the true spirit and 
scope of the invention may be conceived by those or ordinary skill in the 
art. It is intended that all such modifications and refinements be covered 
by the following claims.